gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "tree.h"
  33 #include "langhooks.h"
  34 #include "c-tree.h"
  35 #include "c-lang.h"
  36 #include "flags.h"
  37 #include "output.h"
  38 #include "toplev.h"
  39 #include "intl.h"
  40 #include "target.h"
  41 #include "tree-iterator.h"
  42 #include "bitmap.h"
  43 #include "gimple.h"
  44
  45 /* Possible cases of implicit bad conversions.  Used to select
  46    diagnostic messages in convert_for_assignment.  */
  47 enum impl_conv {
  48   ic_argpass,
  49   ic_assign,
  50   ic_init,
  51   ic_return
  52 };
  53
  54 /* The level of nesting inside "__alignof__".  */
  55 int in_alignof;
  56
  57 /* The level of nesting inside "sizeof".  */
  58 int in_sizeof;
  59
  60 /* The level of nesting inside "typeof".  */
  61 int in_typeof;
  62
  63 /* Nonzero if we've already printed a "missing braces around initializer"
  64    message within this initializer.  */
  65 static int missing_braces_mentioned;
  66
  67 static int require_constant_value;
  68 static int require_constant_elements;
  69
  70 static bool null_pointer_constant_p (const_tree);
  71 static tree qualify_type (tree, tree);
  72 static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *,
  73                                          bool *);
  74 static int comp_target_types (location_t, tree, tree);
  75 static int function_types_compatible_p (const_tree, const_tree, bool *,
  76                                         bool *);
  77 static int type_lists_compatible_p (const_tree, const_tree, bool *, bool *);
  78 static tree lookup_field (tree, tree);
  79 static int convert_arguments (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
  80                               tree);
  81 static tree pointer_diff (location_t, tree, tree);
  82 static tree convert_for_assignment (location_t, tree, tree, tree,
  83                                     enum impl_conv, bool, tree, tree, int);
  84 static tree valid_compound_expr_initializer (tree, tree);
  85 static void push_string (const char *);
  86 static void push_member_name (tree);
  87 static int spelling_length (void);
  88 static char *print_spelling (char *);
  89 static void warning_init (int, const char *);
  90 static tree digest_init (location_t, tree, tree, tree, bool, bool, int);
  91 static void output_init_element (tree, tree, bool, tree, tree, int, bool,
  92                                  struct obstack *);
  93 static void output_pending_init_elements (int, struct obstack *);
  94 static int set_designator (int, struct obstack *);
  95 static void push_range_stack (tree, struct obstack *);
  96 static void add_pending_init (tree, tree, tree, bool, struct obstack *);
  97 static void set_nonincremental_init (struct obstack *);
  98 static void set_nonincremental_init_from_string (tree, struct obstack *);
  99 static tree find_init_member (tree, struct obstack *);
 100 static void readonly_error (tree, enum lvalue_use);
 101 static void readonly_warning (tree, enum lvalue_use);
 102 static int lvalue_or_else (const_tree, enum lvalue_use);
 103 static void record_maybe_used_decl (tree);
 104 static int comptypes_internal (const_tree, const_tree, bool *, bool *);
 105 \f
 106 /* Return true if EXP is a null pointer constant, false otherwise.  */
 107
 108 static bool
 109 null_pointer_constant_p (const_tree expr)
 110 {
 111   /* This should really operate on c_expr structures, but they aren't
 112      yet available everywhere required.  */
 113   tree type = TREE_TYPE (expr);
 114   return (TREE_CODE (expr) == INTEGER_CST
 115           && !TREE_OVERFLOW (expr)
 116           && integer_zerop (expr)
 117           && (INTEGRAL_TYPE_P (type)
 118               || (TREE_CODE (type) == POINTER_TYPE
 119                   && VOID_TYPE_P (TREE_TYPE (type))
 120                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 121 }
 122
 123 /* EXPR may appear in an unevaluated part of an integer constant
 124    expression, but not in an evaluated part.  Wrap it in a
 125    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 126    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 127
 128 static tree
 129 note_integer_operands (tree expr)
 130 {
 131   tree ret;
 132   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 133     {
 134       ret = copy_node (expr);
 135       TREE_OVERFLOW (ret) = 1;
 136     }
 137   else
 138     {
 139       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 140       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 141     }
 142   return ret;
 143 }
 144
 145 /* Having checked whether EXPR may appear in an unevaluated part of an
 146    integer constant expression and found that it may, remove any
 147    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 148    expression.  */
 149
 150 static inline tree
 151 remove_c_maybe_const_expr (tree expr)
 152 {
 153   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 154     return C_MAYBE_CONST_EXPR_EXPR (expr);
 155   else
 156     return expr;
 157 }
 158
 159 \f/* This is a cache to hold if two types are compatible or not.  */
 160
 161 struct tagged_tu_seen_cache {
 162   const struct tagged_tu_seen_cache * next;
 163   const_tree t1;
 164   const_tree t2;
 165   /* The return value of tagged_types_tu_compatible_p if we had seen
 166      these two types already.  */
 167   int val;
 168 };
 169
 170 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 171 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 172
 173 /* Do `exp = require_complete_type (exp);' to make sure exp
 174    does not have an incomplete type.  (That includes void types.)  */
 175
 176 tree
 177 require_complete_type (tree value)
 178 {
 179   tree type = TREE_TYPE (value);
 180
 181   if (value == error_mark_node || type == error_mark_node)
 182     return error_mark_node;
 183
 184   /* First, detect a valid value with a complete type.  */
 185   if (COMPLETE_TYPE_P (type))
 186     return value;
 187
 188   c_incomplete_type_error (value, type);
 189   return error_mark_node;
 190 }
 191
 192 /* Print an error message for invalid use of an incomplete type.
 193    VALUE is the expression that was used (or 0 if that isn't known)
 194    and TYPE is the type that was invalid.  */
 195
 196 void
 197 c_incomplete_type_error (const_tree value, const_tree type)
 198 {
 199   const char *type_code_string;
 200
 201   /* Avoid duplicate error message.  */
 202   if (TREE_CODE (type) == ERROR_MARK)
 203     return;
 204
 205   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 206                      || TREE_CODE (value) == PARM_DECL))
 207     error ("%qD has an incomplete type", value);
 208   else
 209     {
 210     retry:
 211       /* We must print an error message.  Be clever about what it says.  */
 212
 213       switch (TREE_CODE (type))
 214         {
 215         case RECORD_TYPE:
 216           type_code_string = "struct";
 217           break;
 218
 219         case UNION_TYPE:
 220           type_code_string = "union";
 221           break;
 222
 223         case ENUMERAL_TYPE:
 224           type_code_string = "enum";
 225           break;
 226
 227         case VOID_TYPE:
 228           error ("invalid use of void expression");
 229           return;
 230
 231         case ARRAY_TYPE:
 232           if (TYPE_DOMAIN (type))
 233             {
 234               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 235                 {
 236                   error ("invalid use of flexible array member");
 237                   return;
 238                 }
 239               type = TREE_TYPE (type);
 240               goto retry;
 241             }
 242           error ("invalid use of array with unspecified bounds");
 243           return;
 244
 245         default:
 246           gcc_unreachable ();
 247         }
 248
 249       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 250         error ("invalid use of undefined type %<%s %E%>",
 251                type_code_string, TYPE_NAME (type));
 252       else
 253         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 254         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 255     }
 256 }
 257
 258 /* Given a type, apply default promotions wrt unnamed function
 259    arguments and return the new type.  */
 260
 261 tree
 262 c_type_promotes_to (tree type)
 263 {
 264   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 265     return double_type_node;
 266
 267   if (c_promoting_integer_type_p (type))
 268     {
 269       /* Preserve unsignedness if not really getting any wider.  */
 270       if (TYPE_UNSIGNED (type)
 271           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 272         return unsigned_type_node;
 273       return integer_type_node;
 274     }
 275
 276   return type;
 277 }
 278
 279 /* Return true if between two named address spaces, whether there is a superset
 280    named address space that encompasses both address spaces.  If there is a
 281    superset, return which address space is the superset.  */
 282
 283 static bool
 284 addr_space_superset (addr_space_t as1, addr_space_t as2, addr_space_t *common)
 285 {
 286   if (as1 == as2)
 287     {
 288       *common = as1;
 289       return true;
 290     }
 291   else if (targetm.addr_space.subset_p (as1, as2))
 292     {
 293       *common = as2;
 294       return true;
 295     }
 296   else if (targetm.addr_space.subset_p (as2, as1))
 297     {
 298       *common = as1;
 299       return true;
 300     }
 301   else
 302     return false;
 303 }
 304
 305 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 306    as well as those of TYPE.  */
 307
 308 static tree
 309 qualify_type (tree type, tree like)
 310 {
 311   addr_space_t as_type = TYPE_ADDR_SPACE (type);
 312   addr_space_t as_like = TYPE_ADDR_SPACE (like);
 313   addr_space_t as_common;
 314
 315   /* If the two named address spaces are different, determine the common
 316      superset address space.  If there isn't one, raise an error.  */
 317   if (!addr_space_superset (as_type, as_like, &as_common))
 318     {
 319       as_common = as_type;
 320       error ("%qT and %qT are in disjoint named address spaces",
 321              type, like);
 322     }
 323
 324   return c_build_qualified_type (type,
 325                                  TYPE_QUALS_NO_ADDR_SPACE (type)
 326                                  | TYPE_QUALS_NO_ADDR_SPACE (like)
 327                                  | ENCODE_QUAL_ADDR_SPACE (as_common));
 328 }
 329
 330 /* Return true iff the given tree T is a variable length array.  */
 331
 332 bool
 333 c_vla_type_p (const_tree t)
 334 {
 335   if (TREE_CODE (t) == ARRAY_TYPE
 336       && C_TYPE_VARIABLE_SIZE (t))
 337     return true;
 338   return false;
 339 }
 340 \f
 341 /* Return the composite type of two compatible types.
 342
 343    We assume that comptypes has already been done and returned
 344    nonzero; if that isn't so, this may crash.  In particular, we
 345    assume that qualifiers match.  */
 346
 347 tree
 348 composite_type (tree t1, tree t2)
 349 {
 350   enum tree_code code1;
 351   enum tree_code code2;
 352   tree attributes;
 353
 354   /* Save time if the two types are the same.  */
 355
 356   if (t1 == t2) return t1;
 357
 358   /* If one type is nonsense, use the other.  */
 359   if (t1 == error_mark_node)
 360     return t2;
 361   if (t2 == error_mark_node)
 362     return t1;
 363
 364   code1 = TREE_CODE (t1);
 365   code2 = TREE_CODE (t2);
 366
 367   /* Merge the attributes.  */
 368   attributes = targetm.merge_type_attributes (t1, t2);
 369
 370   /* If one is an enumerated type and the other is the compatible
 371      integer type, the composite type might be either of the two
 372      (DR#013 question 3).  For consistency, use the enumerated type as
 373      the composite type.  */
 374
 375   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 376     return t1;
 377   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 378     return t2;
 379
 380   gcc_assert (code1 == code2);
 381
 382   switch (code1)
 383     {
 384     case POINTER_TYPE:
 385       /* For two pointers, do this recursively on the target type.  */
 386       {
 387         tree pointed_to_1 = TREE_TYPE (t1);
 388         tree pointed_to_2 = TREE_TYPE (t2);
 389         tree target = composite_type (pointed_to_1, pointed_to_2);
 390         t1 = build_pointer_type (target);
 391         t1 = build_type_attribute_variant (t1, attributes);
 392         return qualify_type (t1, t2);
 393       }
 394
 395     case ARRAY_TYPE:
 396       {
 397         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 398         int quals;
 399         tree unqual_elt;
 400         tree d1 = TYPE_DOMAIN (t1);
 401         tree d2 = TYPE_DOMAIN (t2);
 402         bool d1_variable, d2_variable;
 403         bool d1_zero, d2_zero;
 404         bool t1_complete, t2_complete;
 405
 406         /* We should not have any type quals on arrays at all.  */
 407         gcc_assert (!TYPE_QUALS_NO_ADDR_SPACE (t1)
 408                     && !TYPE_QUALS_NO_ADDR_SPACE (t2));
 409
 410         t1_complete = COMPLETE_TYPE_P (t1);
 411         t2_complete = COMPLETE_TYPE_P (t2);
 412
 413         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 414         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 415
 416         d1_variable = (!d1_zero
 417                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 418                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 419         d2_variable = (!d2_zero
 420                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 421                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 422         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 423         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 424
 425         /* Save space: see if the result is identical to one of the args.  */
 426         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 427             && (d2_variable || d2_zero || !d1_variable))
 428           return build_type_attribute_variant (t1, attributes);
 429         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 430             && (d1_variable || d1_zero || !d2_variable))
 431           return build_type_attribute_variant (t2, attributes);
 432
 433         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 434           return build_type_attribute_variant (t1, attributes);
 435         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 436           return build_type_attribute_variant (t2, attributes);
 437
 438         /* Merge the element types, and have a size if either arg has
 439            one.  We may have qualifiers on the element types.  To set
 440            up TYPE_MAIN_VARIANT correctly, we need to form the
 441            composite of the unqualified types and add the qualifiers
 442            back at the end.  */
 443         quals = TYPE_QUALS (strip_array_types (elt));
 444         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 445         t1 = build_array_type (unqual_elt,
 446                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 447                                              && (d2_variable
 448                                                  || d2_zero
 449                                                  || !d1_variable))
 450                                             ? t1
 451                                             : t2));
 452         /* Ensure a composite type involving a zero-length array type
 453            is a zero-length type not an incomplete type.  */
 454         if (d1_zero && d2_zero
 455             && (t1_complete || t2_complete)
 456             && !COMPLETE_TYPE_P (t1))
 457           {
 458             TYPE_SIZE (t1) = bitsize_zero_node;
 459             TYPE_SIZE_UNIT (t1) = size_zero_node;
 460           }
 461         t1 = c_build_qualified_type (t1, quals);
 462         return build_type_attribute_variant (t1, attributes);
 463       }
 464
 465     case ENUMERAL_TYPE:
 466     case RECORD_TYPE:
 467     case UNION_TYPE:
 468       if (attributes != NULL)
 469         {
 470           /* Try harder not to create a new aggregate type.  */
 471           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 472             return t1;
 473           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 474             return t2;
 475         }
 476       return build_type_attribute_variant (t1, attributes);
 477
 478     case FUNCTION_TYPE:
 479       /* Function types: prefer the one that specified arg types.
 480          If both do, merge the arg types.  Also merge the return types.  */
 481       {
 482         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 483         tree p1 = TYPE_ARG_TYPES (t1);
 484         tree p2 = TYPE_ARG_TYPES (t2);
 485         int len;
 486         tree newargs, n;
 487         int i;
 488
 489         /* Save space: see if the result is identical to one of the args.  */
 490         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 491           return build_type_attribute_variant (t1, attributes);
 492         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 493           return build_type_attribute_variant (t2, attributes);
 494
 495         /* Simple way if one arg fails to specify argument types.  */
 496         if (TYPE_ARG_TYPES (t1) == 0)
 497          {
 498             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 499             t1 = build_type_attribute_variant (t1, attributes);
 500             return qualify_type (t1, t2);
 501          }
 502         if (TYPE_ARG_TYPES (t2) == 0)
 503          {
 504            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 505            t1 = build_type_attribute_variant (t1, attributes);
 506            return qualify_type (t1, t2);
 507          }
 508
 509         /* If both args specify argument types, we must merge the two
 510            lists, argument by argument.  */
 511         /* Tell global_bindings_p to return false so that variable_size
 512            doesn't die on VLAs in parameter types.  */
 513         c_override_global_bindings_to_false = true;
 514
 515         len = list_length (p1);
 516         newargs = 0;
 517
 518         for (i = 0; i < len; i++)
 519           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 520
 521         n = newargs;
 522
 523         for (; p1;
 524              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 525           {
 526             /* A null type means arg type is not specified.
 527                Take whatever the other function type has.  */
 528             if (TREE_VALUE (p1) == 0)
 529               {
 530                 TREE_VALUE (n) = TREE_VALUE (p2);
 531                 goto parm_done;
 532               }
 533             if (TREE_VALUE (p2) == 0)
 534               {
 535                 TREE_VALUE (n) = TREE_VALUE (p1);
 536                 goto parm_done;
 537               }
 538
 539             /* Given  wait (union {union wait *u; int *i} *)
 540                and  wait (union wait *),
 541                prefer  union wait *  as type of parm.  */
 542             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 543                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 544               {
 545                 tree memb;
 546                 tree mv2 = TREE_VALUE (p2);
 547                 if (mv2 && mv2 != error_mark_node
 548                     && TREE_CODE (mv2) != ARRAY_TYPE)
 549                   mv2 = TYPE_MAIN_VARIANT (mv2);
 550                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 551                      memb; memb = DECL_CHAIN (memb))
 552                   {
 553                     tree mv3 = TREE_TYPE (memb);
 554                     if (mv3 && mv3 != error_mark_node
 555                         && TREE_CODE (mv3) != ARRAY_TYPE)
 556                       mv3 = TYPE_MAIN_VARIANT (mv3);
 557                     if (comptypes (mv3, mv2))
 558                       {
 559                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 560                                                          TREE_VALUE (p2));
 561                         pedwarn (input_location, OPT_pedantic,
 562                                  "function types not truly compatible in ISO C");
 563                         goto parm_done;
 564                       }
 565                   }
 566               }
 567             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 568                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 569               {
 570                 tree memb;
 571                 tree mv1 = TREE_VALUE (p1);
 572                 if (mv1 && mv1 != error_mark_node
 573                     && TREE_CODE (mv1) != ARRAY_TYPE)
 574                   mv1 = TYPE_MAIN_VARIANT (mv1);
 575                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 576                      memb; memb = DECL_CHAIN (memb))
 577                   {
 578                     tree mv3 = TREE_TYPE (memb);
 579                     if (mv3 && mv3 != error_mark_node
 580                         && TREE_CODE (mv3) != ARRAY_TYPE)
 581                       mv3 = TYPE_MAIN_VARIANT (mv3);
 582                     if (comptypes (mv3, mv1))
 583                       {
 584                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 585                                                          TREE_VALUE (p1));
 586                         pedwarn (input_location, OPT_pedantic,
 587                                  "function types not truly compatible in ISO C");
 588                         goto parm_done;
 589                       }
 590                   }
 591               }
 592             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 593           parm_done: ;
 594           }
 595
 596         c_override_global_bindings_to_false = false;
 597         t1 = build_function_type (valtype, newargs);
 598         t1 = qualify_type (t1, t2);
 599         /* ... falls through ...  */
 600       }
 601
 602     default:
 603       return build_type_attribute_variant (t1, attributes);
 604     }
 605
 606 }
 607
 608 /* Return the type of a conditional expression between pointers to
 609    possibly differently qualified versions of compatible types.
 610
 611    We assume that comp_target_types has already been done and returned
 612    nonzero; if that isn't so, this may crash.  */
 613
 614 static tree
 615 common_pointer_type (tree t1, tree t2)
 616 {
 617   tree attributes;
 618   tree pointed_to_1, mv1;
 619   tree pointed_to_2, mv2;
 620   tree target;
 621   unsigned target_quals;
 622   addr_space_t as1, as2, as_common;
 623   int quals1, quals2;
 624
 625   /* Save time if the two types are the same.  */
 626
 627   if (t1 == t2) return t1;
 628
 629   /* If one type is nonsense, use the other.  */
 630   if (t1 == error_mark_node)
 631     return t2;
 632   if (t2 == error_mark_node)
 633     return t1;
 634
 635   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 636               && TREE_CODE (t2) == POINTER_TYPE);
 637
 638   /* Merge the attributes.  */
 639   attributes = targetm.merge_type_attributes (t1, t2);
 640
 641   /* Find the composite type of the target types, and combine the
 642      qualifiers of the two types' targets.  Do not lose qualifiers on
 643      array element types by taking the TYPE_MAIN_VARIANT.  */
 644   mv1 = pointed_to_1 = TREE_TYPE (t1);
 645   mv2 = pointed_to_2 = TREE_TYPE (t2);
 646   if (TREE_CODE (mv1) != ARRAY_TYPE)
 647     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 648   if (TREE_CODE (mv2) != ARRAY_TYPE)
 649     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 650   target = composite_type (mv1, mv2);
 651
 652   /* For function types do not merge const qualifiers, but drop them
 653      if used inconsistently.  The middle-end uses these to mark const
 654      and noreturn functions.  */
 655   quals1 = TYPE_QUALS_NO_ADDR_SPACE (pointed_to_1);
 656   quals2 = TYPE_QUALS_NO_ADDR_SPACE (pointed_to_2);
 657
 658   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 659     target_quals = (quals1 & quals2);
 660   else
 661     target_quals = (quals1 | quals2);
 662
 663   /* If the two named address spaces are different, determine the common
 664      superset address space.  This is guaranteed to exist due to the
 665      assumption that comp_target_type returned non-zero.  */
 666   as1 = TYPE_ADDR_SPACE (pointed_to_1);
 667   as2 = TYPE_ADDR_SPACE (pointed_to_2);
 668   if (!addr_space_superset (as1, as2, &as_common))
 669     gcc_unreachable ();
 670
 671   target_quals |= ENCODE_QUAL_ADDR_SPACE (as_common);
 672
 673   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 674   return build_type_attribute_variant (t1, attributes);
 675 }
 676
 677 /* Return the common type for two arithmetic types under the usual
 678    arithmetic conversions.  The default conversions have already been
 679    applied, and enumerated types converted to their compatible integer
 680    types.  The resulting type is unqualified and has no attributes.
 681
 682    This is the type for the result of most arithmetic operations
 683    if the operands have the given two types.  */
 684
 685 static tree
 686 c_common_type (tree t1, tree t2)
 687 {
 688   enum tree_code code1;
 689   enum tree_code code2;
 690
 691   /* If one type is nonsense, use the other.  */
 692   if (t1 == error_mark_node)
 693     return t2;
 694   if (t2 == error_mark_node)
 695     return t1;
 696
 697   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 698     t1 = TYPE_MAIN_VARIANT (t1);
 699
 700   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 701     t2 = TYPE_MAIN_VARIANT (t2);
 702
 703   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 704     t1 = build_type_attribute_variant (t1, NULL_TREE);
 705
 706   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 707     t2 = build_type_attribute_variant (t2, NULL_TREE);
 708
 709   /* Save time if the two types are the same.  */
 710
 711   if (t1 == t2) return t1;
 712
 713   code1 = TREE_CODE (t1);
 714   code2 = TREE_CODE (t2);
 715
 716   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 717               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 718               || code1 == INTEGER_TYPE);
 719   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 720               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 721               || code2 == INTEGER_TYPE);
 722
 723   /* When one operand is a decimal float type, the other operand cannot be
 724      a generic float type or a complex type.  We also disallow vector types
 725      here.  */
 726   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 727       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 728     {
 729       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 730         {
 731           error ("can%'t mix operands of decimal float and vector types");
 732           return error_mark_node;
 733         }
 734       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 735         {
 736           error ("can%'t mix operands of decimal float and complex types");
 737           return error_mark_node;
 738         }
 739       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 740         {
 741           error ("can%'t mix operands of decimal float and other float types");
 742           return error_mark_node;
 743         }
 744     }
 745
 746   /* If one type is a vector type, return that type.  (How the usual
 747      arithmetic conversions apply to the vector types extension is not
 748      precisely specified.)  */
 749   if (code1 == VECTOR_TYPE)
 750     return t1;
 751
 752   if (code2 == VECTOR_TYPE)
 753     return t2;
 754
 755   /* If one type is complex, form the common type of the non-complex
 756      components, then make that complex.  Use T1 or T2 if it is the
 757      required type.  */
 758   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 759     {
 760       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 761       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 762       tree subtype = c_common_type (subtype1, subtype2);
 763
 764       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 765         return t1;
 766       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 767         return t2;
 768       else
 769         return build_complex_type (subtype);
 770     }
 771
 772   /* If only one is real, use it as the result.  */
 773
 774   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 775     return t1;
 776
 777   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 778     return t2;
 779
 780   /* If both are real and either are decimal floating point types, use
 781      the decimal floating point type with the greater precision. */
 782
 783   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 784     {
 785       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 786           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 787         return dfloat128_type_node;
 788       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 789                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 790         return dfloat64_type_node;
 791       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 792                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 793         return dfloat32_type_node;
 794     }
 795
 796   /* Deal with fixed-point types.  */
 797   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 798     {
 799       unsigned int unsignedp = 0, satp = 0;
 800       enum machine_mode m1, m2;
 801       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 802
 803       m1 = TYPE_MODE (t1);
 804       m2 = TYPE_MODE (t2);
 805
 806       /* If one input type is saturating, the result type is saturating.  */
 807       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 808         satp = 1;
 809
 810       /* If both fixed-point types are unsigned, the result type is unsigned.
 811          When mixing fixed-point and integer types, follow the sign of the
 812          fixed-point type.
 813          Otherwise, the result type is signed.  */
 814       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 815            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 816           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 817               && TYPE_UNSIGNED (t1))
 818           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 819               && TYPE_UNSIGNED (t2)))
 820         unsignedp = 1;
 821
 822       /* The result type is signed.  */
 823       if (unsignedp == 0)
 824         {
 825           /* If the input type is unsigned, we need to convert to the
 826              signed type.  */
 827           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 828             {
 829               enum mode_class mclass = (enum mode_class) 0;
 830               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 831                 mclass = MODE_FRACT;
 832               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 833                 mclass = MODE_ACCUM;
 834               else
 835                 gcc_unreachable ();
 836               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 837             }
 838           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 839             {
 840               enum mode_class mclass = (enum mode_class) 0;
 841               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 842                 mclass = MODE_FRACT;
 843               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 844                 mclass = MODE_ACCUM;
 845               else
 846                 gcc_unreachable ();
 847               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 848             }
 849         }
 850
 851       if (code1 == FIXED_POINT_TYPE)
 852         {
 853           fbit1 = GET_MODE_FBIT (m1);
 854           ibit1 = GET_MODE_IBIT (m1);
 855         }
 856       else
 857         {
 858           fbit1 = 0;
 859           /* Signed integers need to subtract one sign bit.  */
 860           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 861         }
 862
 863       if (code2 == FIXED_POINT_TYPE)
 864         {
 865           fbit2 = GET_MODE_FBIT (m2);
 866           ibit2 = GET_MODE_IBIT (m2);
 867         }
 868       else
 869         {
 870           fbit2 = 0;
 871           /* Signed integers need to subtract one sign bit.  */
 872           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 873         }
 874
 875       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 876       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 877       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 878                                                  satp);
 879     }
 880
 881   /* Both real or both integers; use the one with greater precision.  */
 882
 883   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 884     return t1;
 885   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 886     return t2;
 887
 888   /* Same precision.  Prefer long longs to longs to ints when the
 889      same precision, following the C99 rules on integer type rank
 890      (which are equivalent to the C90 rules for C90 types).  */
 891
 892   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 893       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 894     return long_long_unsigned_type_node;
 895
 896   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 897       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 898     {
 899       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 900         return long_long_unsigned_type_node;
 901       else
 902         return long_long_integer_type_node;
 903     }
 904
 905   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 906       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 907     return long_unsigned_type_node;
 908
 909   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 910       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 911     {
 912       /* But preserve unsignedness from the other type,
 913          since long cannot hold all the values of an unsigned int.  */
 914       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 915         return long_unsigned_type_node;
 916       else
 917         return long_integer_type_node;
 918     }
 919
 920   /* Likewise, prefer long double to double even if same size.  */
 921   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 922       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 923     return long_double_type_node;
 924
 925   /* Otherwise prefer the unsigned one.  */
 926
 927   if (TYPE_UNSIGNED (t1))
 928     return t1;
 929   else
 930     return t2;
 931 }
 932 \f
 933 /* Wrapper around c_common_type that is used by c-common.c and other
 934    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 935    are allowed here and are converted to their compatible integer types.
 936    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 937    preferably a non-Boolean type as the common type.  */
 938 tree
 939 common_type (tree t1, tree t2)
 940 {
 941   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 942     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 943   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 944     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 945
 946   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 947   if (TREE_CODE (t1) == BOOLEAN_TYPE
 948       && TREE_CODE (t2) == BOOLEAN_TYPE)
 949     return boolean_type_node;
 950
 951   /* If either type is BOOLEAN_TYPE, then return the other.  */
 952   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 953     return t2;
 954   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 955     return t1;
 956
 957   return c_common_type (t1, t2);
 958 }
 959
 960 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 961    or various other operations.  Return 2 if they are compatible
 962    but a warning may be needed if you use them together.  */
 963
 964 int
 965 comptypes (tree type1, tree type2)
 966 {
 967   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 968   int val;
 969
 970   val = comptypes_internal (type1, type2, NULL, NULL);
 971   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 972
 973   return val;
 974 }
 975
 976 /* Like comptypes, but if it returns non-zero because enum and int are
 977    compatible, it sets *ENUM_AND_INT_P to true.  */
 978
 979 static int
 980 comptypes_check_enum_int (tree type1, tree type2, bool *enum_and_int_p)
 981 {
 982   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 983   int val;
 984
 985   val = comptypes_internal (type1, type2, enum_and_int_p, NULL);
 986   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 987
 988   return val;
 989 }
 990
 991 /* Like comptypes, but if it returns nonzero for different types, it
 992    sets *DIFFERENT_TYPES_P to true.  */
 993
 994 int
 995 comptypes_check_different_types (tree type1, tree type2,
 996                                  bool *different_types_p)
 997 {
 998   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 999   int val;
1000
1001   val = comptypes_internal (type1, type2, NULL, different_types_p);
1002   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
1003
1004   return val;
1005 }
1006 \f
1007 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
1008    or various other operations.  Return 2 if they are compatible
1009    but a warning may be needed if you use them together.  If
1010    ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
1011    compatible integer type, then this sets *ENUM_AND_INT_P to true;
1012    *ENUM_AND_INT_P is never set to false.  If DIFFERENT_TYPES_P is not
1013    NULL, and the types are compatible but different enough not to be
1014    permitted in C1X typedef redeclarations, then this sets
1015    *DIFFERENT_TYPES_P to true; *DIFFERENT_TYPES_P is never set to
1016    false, but may or may not be set if the types are incompatible.
1017    This differs from comptypes, in that we don't free the seen
1018    types.  */
1019
1020 static int
1021 comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
1022                     bool *different_types_p)
1023 {
1024   const_tree t1 = type1;
1025   const_tree t2 = type2;
1026   int attrval, val;
1027
1028   /* Suppress errors caused by previously reported errors.  */
1029
1030   if (t1 == t2 || !t1 || !t2
1031       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
1032     return 1;
1033
1034   /* Enumerated types are compatible with integer types, but this is
1035      not transitive: two enumerated types in the same translation unit
1036      are compatible with each other only if they are the same type.  */
1037
1038   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
1039     {
1040       t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
1041       if (TREE_CODE (t2) != VOID_TYPE)
1042         {
1043           if (enum_and_int_p != NULL)
1044             *enum_and_int_p = true;
1045           if (different_types_p != NULL)
1046             *different_types_p = true;
1047         }
1048     }
1049   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
1050     {
1051       t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
1052       if (TREE_CODE (t1) != VOID_TYPE)
1053         {
1054           if (enum_and_int_p != NULL)
1055             *enum_and_int_p = true;
1056           if (different_types_p != NULL)
1057             *different_types_p = true;
1058         }
1059     }
1060
1061   if (t1 == t2)
1062     return 1;
1063
1064   /* Different classes of types can't be compatible.  */
1065
1066   if (TREE_CODE (t1) != TREE_CODE (t2))
1067     return 0;
1068
1069   /* Qualifiers must match. C99 6.7.3p9 */
1070
1071   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
1072     return 0;
1073
1074   /* Allow for two different type nodes which have essentially the same
1075      definition.  Note that we already checked for equality of the type
1076      qualifiers (just above).  */
1077
1078   if (TREE_CODE (t1) != ARRAY_TYPE
1079       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
1080     return 1;
1081
1082   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1083   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
1084      return 0;
1085
1086   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1087   val = 0;
1088
1089   switch (TREE_CODE (t1))
1090     {
1091     case POINTER_TYPE:
1092       /* Do not remove mode or aliasing information.  */
1093       if (TYPE_MODE (t1) != TYPE_MODE (t2)
1094           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
1095         break;
1096       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1097              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1098                                        enum_and_int_p, different_types_p));
1099       break;
1100
1101     case FUNCTION_TYPE:
1102       val = function_types_compatible_p (t1, t2, enum_and_int_p,
1103                                          different_types_p);
1104       break;
1105
1106     case ARRAY_TYPE:
1107       {
1108         tree d1 = TYPE_DOMAIN (t1);
1109         tree d2 = TYPE_DOMAIN (t2);
1110         bool d1_variable, d2_variable;
1111         bool d1_zero, d2_zero;
1112         val = 1;
1113
1114         /* Target types must match incl. qualifiers.  */
1115         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1116             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1117                                                enum_and_int_p,
1118                                                different_types_p)))
1119           return 0;
1120
1121         if (different_types_p != NULL
1122             && (d1 == 0) != (d2 == 0))
1123           *different_types_p = true;
1124         /* Sizes must match unless one is missing or variable.  */
1125         if (d1 == 0 || d2 == 0 || d1 == d2)
1126           break;
1127
1128         d1_zero = !TYPE_MAX_VALUE (d1);
1129         d2_zero = !TYPE_MAX_VALUE (d2);
1130
1131         d1_variable = (!d1_zero
1132                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1133                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1134         d2_variable = (!d2_zero
1135                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1136                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1137         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1138         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1139
1140         if (different_types_p != NULL
1141             && d1_variable != d2_variable)
1142           *different_types_p = true;
1143         if (d1_variable || d2_variable)
1144           break;
1145         if (d1_zero && d2_zero)
1146           break;
1147         if (d1_zero || d2_zero
1148             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1149             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1150           val = 0;
1151
1152         break;
1153       }
1154
1155     case ENUMERAL_TYPE:
1156     case RECORD_TYPE:
1157     case UNION_TYPE:
1158       if (val != 1 && !same_translation_unit_p (t1, t2))
1159         {
1160           tree a1 = TYPE_ATTRIBUTES (t1);
1161           tree a2 = TYPE_ATTRIBUTES (t2);
1162
1163           if (! attribute_list_contained (a1, a2)
1164               && ! attribute_list_contained (a2, a1))
1165             break;
1166
1167           if (attrval != 2)
1168             return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p,
1169                                                  different_types_p);
1170           val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p,
1171                                               different_types_p);
1172         }
1173       break;
1174
1175     case VECTOR_TYPE:
1176       val = (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1177              && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1178                                     enum_and_int_p, different_types_p));
1179       break;
1180
1181     default:
1182       break;
1183     }
1184   return attrval == 2 && val == 1 ? 2 : val;
1185 }
1186
1187 /* Return 1 if TTL and TTR are pointers to types that are equivalent, ignoring
1188    their qualifiers, except for named address spaces.  If the pointers point to
1189    different named addresses, then we must determine if one address space is a
1190    subset of the other.  */
1191
1192 static int
1193 comp_target_types (location_t location, tree ttl, tree ttr)
1194 {
1195   int val;
1196   tree mvl = TREE_TYPE (ttl);
1197   tree mvr = TREE_TYPE (ttr);
1198   addr_space_t asl = TYPE_ADDR_SPACE (mvl);
1199   addr_space_t asr = TYPE_ADDR_SPACE (mvr);
1200   addr_space_t as_common;
1201   bool enum_and_int_p;
1202
1203   /* Fail if pointers point to incompatible address spaces.  */
1204   if (!addr_space_superset (asl, asr, &as_common))
1205     return 0;
1206
1207   /* Do not lose qualifiers on element types of array types that are
1208      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1209   if (TREE_CODE (mvl) != ARRAY_TYPE)
1210     mvl = TYPE_MAIN_VARIANT (mvl);
1211   if (TREE_CODE (mvr) != ARRAY_TYPE)
1212     mvr = TYPE_MAIN_VARIANT (mvr);
1213   enum_and_int_p = false;
1214   val = comptypes_check_enum_int (mvl, mvr, &enum_and_int_p);
1215
1216   if (val == 2)
1217     pedwarn (location, OPT_pedantic, "types are not quite compatible");
1218
1219   if (val == 1 && enum_and_int_p && warn_cxx_compat)
1220     warning_at (location, OPT_Wc___compat,
1221                 "pointer target types incompatible in C++");
1222
1223   return val;
1224 }
1225 \f
1226 /* Subroutines of `comptypes'.  */
1227
1228 /* Determine whether two trees derive from the same translation unit.
1229    If the CONTEXT chain ends in a null, that tree's context is still
1230    being parsed, so if two trees have context chains ending in null,
1231    they're in the same translation unit.  */
1232 int
1233 same_translation_unit_p (const_tree t1, const_tree t2)
1234 {
1235   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1236     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1237       {
1238       case tcc_declaration:
1239         t1 = DECL_CONTEXT (t1); break;
1240       case tcc_type:
1241         t1 = TYPE_CONTEXT (t1); break;
1242       case tcc_exceptional:
1243         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1244       default: gcc_unreachable ();
1245       }
1246
1247   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1248     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1249       {
1250       case tcc_declaration:
1251         t2 = DECL_CONTEXT (t2); break;
1252       case tcc_type:
1253         t2 = TYPE_CONTEXT (t2); break;
1254       case tcc_exceptional:
1255         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1256       default: gcc_unreachable ();
1257       }
1258
1259   return t1 == t2;
1260 }
1261
1262 /* Allocate the seen two types, assuming that they are compatible. */
1263
1264 static struct tagged_tu_seen_cache *
1265 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1266 {
1267   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1268   tu->next = tagged_tu_seen_base;
1269   tu->t1 = t1;
1270   tu->t2 = t2;
1271
1272   tagged_tu_seen_base = tu;
1273
1274   /* The C standard says that two structures in different translation
1275      units are compatible with each other only if the types of their
1276      fields are compatible (among other things).  We assume that they
1277      are compatible until proven otherwise when building the cache.
1278      An example where this can occur is:
1279      struct a
1280      {
1281        struct a *next;
1282      };
1283      If we are comparing this against a similar struct in another TU,
1284      and did not assume they were compatible, we end up with an infinite
1285      loop.  */
1286   tu->val = 1;
1287   return tu;
1288 }
1289
1290 /* Free the seen types until we get to TU_TIL. */
1291
1292 static void
1293 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1294 {
1295   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1296   while (tu != tu_til)
1297     {
1298       const struct tagged_tu_seen_cache *const tu1
1299         = (const struct tagged_tu_seen_cache *) tu;
1300       tu = tu1->next;
1301       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1302     }
1303   tagged_tu_seen_base = tu_til;
1304 }
1305
1306 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1307    compatible.  If the two types are not the same (which has been
1308    checked earlier), this can only happen when multiple translation
1309    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1310    rules.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
1311    comptypes_internal.  */
1312
1313 static int
1314 tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
1315                               bool *enum_and_int_p, bool *different_types_p)
1316 {
1317   tree s1, s2;
1318   bool needs_warning = false;
1319
1320   /* We have to verify that the tags of the types are the same.  This
1321      is harder than it looks because this may be a typedef, so we have
1322      to go look at the original type.  It may even be a typedef of a
1323      typedef...
1324      In the case of compiler-created builtin structs the TYPE_DECL
1325      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1326   while (TYPE_NAME (t1)
1327          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1328          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1329     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1330
1331   while (TYPE_NAME (t2)
1332          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1333          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1334     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1335
1336   /* C90 didn't have the requirement that the two tags be the same.  */
1337   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1338     return 0;
1339
1340   /* C90 didn't say what happened if one or both of the types were
1341      incomplete; we choose to follow C99 rules here, which is that they
1342      are compatible.  */
1343   if (TYPE_SIZE (t1) == NULL
1344       || TYPE_SIZE (t2) == NULL)
1345     return 1;
1346
1347   {
1348     const struct tagged_tu_seen_cache * tts_i;
1349     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1350       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1351         return tts_i->val;
1352   }
1353
1354   switch (TREE_CODE (t1))
1355     {
1356     case ENUMERAL_TYPE:
1357       {
1358         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1359         /* Speed up the case where the type values are in the same order.  */
1360         tree tv1 = TYPE_VALUES (t1);
1361         tree tv2 = TYPE_VALUES (t2);
1362
1363         if (tv1 == tv2)
1364           {
1365             return 1;
1366           }
1367
1368         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1369           {
1370             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1371               break;
1372             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1373               {
1374                 tu->val = 0;
1375                 return 0;
1376               }
1377           }
1378
1379         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1380           {
1381             return 1;
1382           }
1383         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1384           {
1385             tu->val = 0;
1386             return 0;
1387           }
1388
1389         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1390           {
1391             tu->val = 0;
1392             return 0;
1393           }
1394
1395         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1396           {
1397             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1398             if (s2 == NULL
1399                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1400               {
1401                 tu->val = 0;
1402                 return 0;
1403               }
1404           }
1405         return 1;
1406       }
1407
1408     case UNION_TYPE:
1409       {
1410         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1411         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1412           {
1413             tu->val = 0;
1414             return 0;
1415           }
1416
1417         /*  Speed up the common case where the fields are in the same order. */
1418         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1419              s1 = DECL_CHAIN (s1), s2 = DECL_CHAIN (s2))
1420           {
1421             int result;
1422
1423             if (DECL_NAME (s1) != DECL_NAME (s2))
1424               break;
1425             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1426                                          enum_and_int_p, different_types_p);
1427
1428             if (result != 1 && !DECL_NAME (s1))
1429               break;
1430             if (result == 0)
1431               {
1432                 tu->val = 0;
1433                 return 0;
1434               }
1435             if (result == 2)
1436               needs_warning = true;
1437
1438             if (TREE_CODE (s1) == FIELD_DECL
1439                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1440                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1441               {
1442                 tu->val = 0;
1443                 return 0;
1444               }
1445           }
1446         if (!s1 && !s2)
1447           {
1448             tu->val = needs_warning ? 2 : 1;
1449             return tu->val;
1450           }
1451
1452         for (s1 = TYPE_FIELDS (t1); s1; s1 = DECL_CHAIN (s1))
1453           {
1454             bool ok = false;
1455
1456             for (s2 = TYPE_FIELDS (t2); s2; s2 = DECL_CHAIN (s2))
1457               if (DECL_NAME (s1) == DECL_NAME (s2))
1458                 {
1459                   int result;
1460
1461                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1462                                                enum_and_int_p,
1463                                                different_types_p);
1464
1465                   if (result != 1 && !DECL_NAME (s1))
1466                     continue;
1467                   if (result == 0)
1468                     {
1469                       tu->val = 0;
1470                       return 0;
1471                     }
1472                   if (result == 2)
1473                     needs_warning = true;
1474
1475                   if (TREE_CODE (s1) == FIELD_DECL
1476                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1477                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1478                     break;
1479
1480                   ok = true;
1481                   break;
1482                 }
1483             if (!ok)
1484               {
1485                 tu->val = 0;
1486                 return 0;
1487               }
1488           }
1489         tu->val = needs_warning ? 2 : 10;
1490         return tu->val;
1491       }
1492
1493     case RECORD_TYPE:
1494       {
1495         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1496
1497         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1498              s1 && s2;
1499              s1 = DECL_CHAIN (s1), s2 = DECL_CHAIN (s2))
1500           {
1501             int result;
1502             if (TREE_CODE (s1) != TREE_CODE (s2)
1503                 || DECL_NAME (s1) != DECL_NAME (s2))
1504               break;
1505             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1506                                          enum_and_int_p, different_types_p);
1507             if (result == 0)
1508               break;
1509             if (result == 2)
1510               needs_warning = true;
1511
1512             if (TREE_CODE (s1) == FIELD_DECL
1513                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1514                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1515               break;
1516           }
1517         if (s1 && s2)
1518           tu->val = 0;
1519         else
1520           tu->val = needs_warning ? 2 : 1;
1521         return tu->val;
1522       }
1523
1524     default:
1525       gcc_unreachable ();
1526     }
1527 }
1528
1529 /* Return 1 if two function types F1 and F2 are compatible.
1530    If either type specifies no argument types,
1531    the other must specify a fixed number of self-promoting arg types.
1532    Otherwise, if one type specifies only the number of arguments,
1533    the other must specify that number of self-promoting arg types.
1534    Otherwise, the argument types must match.
1535    ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in comptypes_internal.  */
1536
1537 static int
1538 function_types_compatible_p (const_tree f1, const_tree f2,
1539                              bool *enum_and_int_p, bool *different_types_p)
1540 {
1541   tree args1, args2;
1542   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1543   int val = 1;
1544   int val1;
1545   tree ret1, ret2;
1546
1547   ret1 = TREE_TYPE (f1);
1548   ret2 = TREE_TYPE (f2);
1549
1550   /* 'volatile' qualifiers on a function's return type used to mean
1551      the function is noreturn.  */
1552   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1553     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1554   if (TYPE_VOLATILE (ret1))
1555     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1556                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1557   if (TYPE_VOLATILE (ret2))
1558     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1559                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1560   val = comptypes_internal (ret1, ret2, enum_and_int_p, different_types_p);
1561   if (val == 0)
1562     return 0;
1563
1564   args1 = TYPE_ARG_TYPES (f1);
1565   args2 = TYPE_ARG_TYPES (f2);
1566
1567   if (different_types_p != NULL
1568       && (args1 == 0) != (args2 == 0))
1569     *different_types_p = true;
1570
1571   /* An unspecified parmlist matches any specified parmlist
1572      whose argument types don't need default promotions.  */
1573
1574   if (args1 == 0)
1575     {
1576       if (!self_promoting_args_p (args2))
1577         return 0;
1578       /* If one of these types comes from a non-prototype fn definition,
1579          compare that with the other type's arglist.
1580          If they don't match, ask for a warning (but no error).  */
1581       if (TYPE_ACTUAL_ARG_TYPES (f1)
1582           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
1583                                            enum_and_int_p, different_types_p))
1584         val = 2;
1585       return val;
1586     }
1587   if (args2 == 0)
1588     {
1589       if (!self_promoting_args_p (args1))
1590         return 0;
1591       if (TYPE_ACTUAL_ARG_TYPES (f2)
1592           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
1593                                            enum_and_int_p, different_types_p))
1594         val = 2;
1595       return val;
1596     }
1597
1598   /* Both types have argument lists: compare them and propagate results.  */
1599   val1 = type_lists_compatible_p (args1, args2, enum_and_int_p,
1600                                   different_types_p);
1601   return val1 != 1 ? val1 : val;
1602 }
1603
1604 /* Check two lists of types for compatibility, returning 0 for
1605    incompatible, 1 for compatible, or 2 for compatible with
1606    warning.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
1607    comptypes_internal.  */
1608
1609 static int
1610 type_lists_compatible_p (const_tree args1, const_tree args2,
1611                          bool *enum_and_int_p, bool *different_types_p)
1612 {
1613   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1614   int val = 1;
1615   int newval = 0;
1616
1617   while (1)
1618     {
1619       tree a1, mv1, a2, mv2;
1620       if (args1 == 0 && args2 == 0)
1621         return val;
1622       /* If one list is shorter than the other,
1623          they fail to match.  */
1624       if (args1 == 0 || args2 == 0)
1625         return 0;
1626       mv1 = a1 = TREE_VALUE (args1);
1627       mv2 = a2 = TREE_VALUE (args2);
1628       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1629         mv1 = TYPE_MAIN_VARIANT (mv1);
1630       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1631         mv2 = TYPE_MAIN_VARIANT (mv2);
1632       /* A null pointer instead of a type
1633          means there is supposed to be an argument
1634          but nothing is specified about what type it has.
1635          So match anything that self-promotes.  */
1636       if (different_types_p != NULL
1637           && (a1 == 0) != (a2 == 0))
1638         *different_types_p = true;
1639       if (a1 == 0)
1640         {
1641           if (c_type_promotes_to (a2) != a2)
1642             return 0;
1643         }
1644       else if (a2 == 0)
1645         {
1646           if (c_type_promotes_to (a1) != a1)
1647             return 0;
1648         }
1649       /* If one of the lists has an error marker, ignore this arg.  */
1650       else if (TREE_CODE (a1) == ERROR_MARK
1651                || TREE_CODE (a2) == ERROR_MARK)
1652         ;
1653       else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p,
1654                                               different_types_p)))
1655         {
1656           if (different_types_p != NULL)
1657             *different_types_p = true;
1658           /* Allow  wait (union {union wait *u; int *i} *)
1659              and  wait (union wait *)  to be compatible.  */
1660           if (TREE_CODE (a1) == UNION_TYPE
1661               && (TYPE_NAME (a1) == 0
1662                   || TYPE_TRANSPARENT_AGGR (a1))
1663               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1664               && tree_int_cst_equal (TYPE_SIZE (a1),
1665                                      TYPE_SIZE (a2)))
1666             {
1667               tree memb;
1668               for (memb = TYPE_FIELDS (a1);
1669                    memb; memb = DECL_CHAIN (memb))
1670                 {
1671                   tree mv3 = TREE_TYPE (memb);
1672                   if (mv3 && mv3 != error_mark_node
1673                       && TREE_CODE (mv3) != ARRAY_TYPE)
1674                     mv3 = TYPE_MAIN_VARIANT (mv3);
1675                   if (comptypes_internal (mv3, mv2, enum_and_int_p,
1676                                           different_types_p))
1677                     break;
1678                 }
1679               if (memb == 0)
1680                 return 0;
1681             }
1682           else if (TREE_CODE (a2) == UNION_TYPE
1683                    && (TYPE_NAME (a2) == 0
1684                        || TYPE_TRANSPARENT_AGGR (a2))
1685                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1686                    && tree_int_cst_equal (TYPE_SIZE (a2),
1687                                           TYPE_SIZE (a1)))
1688             {
1689               tree memb;
1690               for (memb = TYPE_FIELDS (a2);
1691                    memb; memb = DECL_CHAIN (memb))
1692                 {
1693                   tree mv3 = TREE_TYPE (memb);
1694                   if (mv3 && mv3 != error_mark_node
1695                       && TREE_CODE (mv3) != ARRAY_TYPE)
1696                     mv3 = TYPE_MAIN_VARIANT (mv3);
1697                   if (comptypes_internal (mv3, mv1, enum_and_int_p,
1698                                           different_types_p))
1699                     break;
1700                 }
1701               if (memb == 0)
1702                 return 0;
1703             }
1704           else
1705             return 0;
1706         }
1707
1708       /* comptypes said ok, but record if it said to warn.  */
1709       if (newval > val)
1710         val = newval;
1711
1712       args1 = TREE_CHAIN (args1);
1713       args2 = TREE_CHAIN (args2);
1714     }
1715 }
1716 \f
1717 /* Compute the size to increment a pointer by.  */
1718
1719 static tree
1720 c_size_in_bytes (const_tree type)
1721 {
1722   enum tree_code code = TREE_CODE (type);
1723
1724   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1725     return size_one_node;
1726
1727   if (!COMPLETE_OR_VOID_TYPE_P (type))
1728     {
1729       error ("arithmetic on pointer to an incomplete type");
1730       return size_one_node;
1731     }
1732
1733   /* Convert in case a char is more than one unit.  */
1734   return size_binop_loc (input_location, CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1735                          size_int (TYPE_PRECISION (char_type_node)
1736                                    / BITS_PER_UNIT));
1737 }
1738 \f
1739 /* Return either DECL or its known constant value (if it has one).  */
1740
1741 tree
1742 decl_constant_value (tree decl)
1743 {
1744   if (/* Don't change a variable array bound or initial value to a constant
1745          in a place where a variable is invalid.  Note that DECL_INITIAL
1746          isn't valid for a PARM_DECL.  */
1747       current_function_decl != 0
1748       && TREE_CODE (decl) != PARM_DECL
1749       && !TREE_THIS_VOLATILE (decl)
1750       && TREE_READONLY (decl)
1751       && DECL_INITIAL (decl) != 0
1752       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1753       /* This is invalid if initial value is not constant.
1754          If it has either a function call, a memory reference,
1755          or a variable, then re-evaluating it could give different results.  */
1756       && TREE_CONSTANT (DECL_INITIAL (decl))
1757       /* Check for cases where this is sub-optimal, even though valid.  */
1758       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1759     return DECL_INITIAL (decl);
1760   return decl;
1761 }
1762
1763 /* Convert the array expression EXP to a pointer.  */
1764 static tree
1765 array_to_pointer_conversion (location_t loc, tree exp)
1766 {
1767   tree orig_exp = exp;
1768   tree type = TREE_TYPE (exp);
1769   tree adr;
1770   tree restype = TREE_TYPE (type);
1771   tree ptrtype;
1772
1773   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1774
1775   STRIP_TYPE_NOPS (exp);
1776
1777   if (TREE_NO_WARNING (orig_exp))
1778     TREE_NO_WARNING (exp) = 1;
1779
1780   ptrtype = build_pointer_type (restype);
1781
1782   if (TREE_CODE (exp) == INDIRECT_REF)
1783     return convert (ptrtype, TREE_OPERAND (exp, 0));
1784
1785   adr = build_unary_op (loc, ADDR_EXPR, exp, 1);
1786   return convert (ptrtype, adr);
1787 }
1788
1789 /* Convert the function expression EXP to a pointer.  */
1790 static tree
1791 function_to_pointer_conversion (location_t loc, tree exp)
1792 {
1793   tree orig_exp = exp;
1794
1795   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1796
1797   STRIP_TYPE_NOPS (exp);
1798
1799   if (TREE_NO_WARNING (orig_exp))
1800     TREE_NO_WARNING (exp) = 1;
1801
1802   return build_unary_op (loc, ADDR_EXPR, exp, 0);
1803 }
1804
1805 /* Mark EXP as read, not just set, for set but not used -Wunused
1806    warning purposes.  */
1807
1808 void
1809 mark_exp_read (tree exp)
1810 {
1811   switch (TREE_CODE (exp))
1812     {
1813     case VAR_DECL:
1814     case PARM_DECL:
1815       DECL_READ_P (exp) = 1;
1816       break;
1817     case ARRAY_REF:
1818     case COMPONENT_REF:
1819     case MODIFY_EXPR:
1820     case REALPART_EXPR:
1821     case IMAGPART_EXPR:
1822     CASE_CONVERT:
1823     case ADDR_EXPR:
1824       mark_exp_read (TREE_OPERAND (exp, 0));
1825       break;
1826     case COMPOUND_EXPR:
1827     case C_MAYBE_CONST_EXPR:
1828       mark_exp_read (TREE_OPERAND (exp, 1));
1829       break;
1830     default:
1831       break;
1832     }
1833 }
1834
1835 /* Perform the default conversion of arrays and functions to pointers.
1836    Return the result of converting EXP.  For any other expression, just
1837    return EXP.
1838
1839    LOC is the location of the expression.  */
1840
1841 struct c_expr
1842 default_function_array_conversion (location_t loc, struct c_expr exp)
1843 {
1844   tree orig_exp = exp.value;
1845   tree type = TREE_TYPE (exp.value);
1846   enum tree_code code = TREE_CODE (type);
1847
1848   switch (code)
1849     {
1850     case ARRAY_TYPE:
1851       {
1852         bool not_lvalue = false;
1853         bool lvalue_array_p;
1854
1855         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1856                 || CONVERT_EXPR_P (exp.value))
1857                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1858           {
1859             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1860               not_lvalue = true;
1861             exp.value = TREE_OPERAND (exp.value, 0);
1862           }
1863
1864         if (TREE_NO_WARNING (orig_exp))
1865           TREE_NO_WARNING (exp.value) = 1;
1866
1867         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1868         if (!flag_isoc99 && !lvalue_array_p)
1869           {
1870             /* Before C99, non-lvalue arrays do not decay to pointers.
1871                Normally, using such an array would be invalid; but it can
1872                be used correctly inside sizeof or as a statement expression.
1873                Thus, do not give an error here; an error will result later.  */
1874             return exp;
1875           }
1876
1877         exp.value = array_to_pointer_conversion (loc, exp.value);
1878       }
1879       break;
1880     case FUNCTION_TYPE:
1881       exp.value = function_to_pointer_conversion (loc, exp.value);
1882       break;
1883     default:
1884       break;
1885     }
1886
1887   return exp;
1888 }
1889
1890 struct c_expr
1891 default_function_array_read_conversion (location_t loc, struct c_expr exp)
1892 {
1893   mark_exp_read (exp.value);
1894   return default_function_array_conversion (loc, exp);
1895 }
1896
1897 /* EXP is an expression of integer type.  Apply the integer promotions
1898    to it and return the promoted value.  */
1899
1900 tree
1901 perform_integral_promotions (tree exp)
1902 {
1903   tree type = TREE_TYPE (exp);
1904   enum tree_code code = TREE_CODE (type);
1905
1906   gcc_assert (INTEGRAL_TYPE_P (type));
1907
1908   /* Normally convert enums to int,
1909      but convert wide enums to something wider.  */
1910   if (code == ENUMERAL_TYPE)
1911     {
1912       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1913                                           TYPE_PRECISION (integer_type_node)),
1914                                      ((TYPE_PRECISION (type)
1915                                        >= TYPE_PRECISION (integer_type_node))
1916                                       && TYPE_UNSIGNED (type)));
1917
1918       return convert (type, exp);
1919     }
1920
1921   /* ??? This should no longer be needed now bit-fields have their
1922      proper types.  */
1923   if (TREE_CODE (exp) == COMPONENT_REF
1924       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1925       /* If it's thinner than an int, promote it like a
1926          c_promoting_integer_type_p, otherwise leave it alone.  */
1927       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1928                                TYPE_PRECISION (integer_type_node)))
1929     return convert (integer_type_node, exp);
1930
1931   if (c_promoting_integer_type_p (type))
1932     {
1933       /* Preserve unsignedness if not really getting any wider.  */
1934       if (TYPE_UNSIGNED (type)
1935           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1936         return convert (unsigned_type_node, exp);
1937
1938       return convert (integer_type_node, exp);
1939     }
1940
1941   return exp;
1942 }
1943
1944
1945 /* Perform default promotions for C data used in expressions.
1946    Enumeral types or short or char are converted to int.
1947    In addition, manifest constants symbols are replaced by their values.  */
1948
1949 tree
1950 default_conversion (tree exp)
1951 {
1952   tree orig_exp;
1953   tree type = TREE_TYPE (exp);
1954   enum tree_code code = TREE_CODE (type);
1955   tree promoted_type;
1956
1957   mark_exp_read (exp);
1958
1959   /* Functions and arrays have been converted during parsing.  */
1960   gcc_assert (code != FUNCTION_TYPE);
1961   if (code == ARRAY_TYPE)
1962     return exp;
1963
1964   /* Constants can be used directly unless they're not loadable.  */
1965   if (TREE_CODE (exp) == CONST_DECL)
1966     exp = DECL_INITIAL (exp);
1967
1968   /* Strip no-op conversions.  */
1969   orig_exp = exp;
1970   STRIP_TYPE_NOPS (exp);
1971
1972   if (TREE_NO_WARNING (orig_exp))
1973     TREE_NO_WARNING (exp) = 1;
1974
1975   if (code == VOID_TYPE)
1976     {
1977       error ("void value not ignored as it ought to be");
1978       return error_mark_node;
1979     }
1980
1981   exp = require_complete_type (exp);
1982   if (exp == error_mark_node)
1983     return error_mark_node;
1984
1985   promoted_type = targetm.promoted_type (type);
1986   if (promoted_type)
1987     return convert (promoted_type, exp);
1988
1989   if (INTEGRAL_TYPE_P (type))
1990     return perform_integral_promotions (exp);
1991
1992   return exp;
1993 }
1994 \f
1995 /* Look up COMPONENT in a structure or union TYPE.
1996
1997    If the component name is not found, returns NULL_TREE.  Otherwise,
1998    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1999    stepping down the chain to the component, which is in the last
2000    TREE_VALUE of the list.  Normally the list is of length one, but if
2001    the component is embedded within (nested) anonymous structures or
2002    unions, the list steps down the chain to the component.  */
2003
2004 static tree
2005 lookup_field (tree type, tree component)
2006 {
2007   tree field;
2008
2009   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
2010      to the field elements.  Use a binary search on this array to quickly
2011      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
2012      will always be set for structures which have many elements.  */
2013
2014   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
2015     {
2016       int bot, top, half;
2017       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
2018
2019       field = TYPE_FIELDS (type);
2020       bot = 0;
2021       top = TYPE_LANG_SPECIFIC (type)->s->len;
2022       while (top - bot > 1)
2023         {
2024           half = (top - bot + 1) >> 1;
2025           field = field_array[bot+half];
2026
2027           if (DECL_NAME (field) == NULL_TREE)
2028             {
2029               /* Step through all anon unions in linear fashion.  */
2030               while (DECL_NAME (field_array[bot]) == NULL_TREE)
2031                 {
2032                   field = field_array[bot++];
2033                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
2034                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
2035                     {
2036                       tree anon = lookup_field (TREE_TYPE (field), component);
2037
2038                       if (anon)
2039                         return tree_cons (NULL_TREE, field, anon);
2040
2041                       /* The Plan 9 compiler permits referring
2042                          directly to an anonymous struct/union field
2043                          using a typedef name.  */
2044                       if (flag_plan9_extensions
2045                           && TYPE_NAME (TREE_TYPE (field)) != NULL_TREE
2046                           && (TREE_CODE (TYPE_NAME (TREE_TYPE (field)))
2047                               == TYPE_DECL)
2048                           && (DECL_NAME (TYPE_NAME (TREE_TYPE (field)))
2049                               == component))
2050                         break;
2051                     }
2052                 }
2053
2054               /* Entire record is only anon unions.  */
2055               if (bot > top)
2056                 return NULL_TREE;
2057
2058               /* Restart the binary search, with new lower bound.  */
2059               continue;
2060             }
2061
2062           if (DECL_NAME (field) == component)
2063             break;
2064           if (DECL_NAME (field) < component)
2065             bot += half;
2066           else
2067             top = bot + half;
2068         }
2069
2070       if (DECL_NAME (field_array[bot]) == component)
2071         field = field_array[bot];
2072       else if (DECL_NAME (field) != component)
2073         return NULL_TREE;
2074     }
2075   else
2076     {
2077       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
2078         {
2079           if (DECL_NAME (field) == NULL_TREE
2080               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
2081                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
2082             {
2083               tree anon = lookup_field (TREE_TYPE (field), component);
2084
2085               if (anon)
2086                 return tree_cons (NULL_TREE, field, anon);
2087
2088               /* The Plan 9 compiler permits referring directly to an
2089                  anonymous struct/union field using a typedef
2090                  name.  */
2091               if (flag_plan9_extensions
2092                   && TYPE_NAME (TREE_TYPE (field)) != NULL_TREE
2093                   && TREE_CODE (TYPE_NAME (TREE_TYPE (field))) == TYPE_DECL
2094                   && (DECL_NAME (TYPE_NAME (TREE_TYPE (field)))
2095                       == component))
2096                 break;
2097             }
2098
2099           if (DECL_NAME (field) == component)
2100             break;
2101         }
2102
2103       if (field == NULL_TREE)
2104         return NULL_TREE;
2105     }
2106
2107   return tree_cons (NULL_TREE, field, NULL_TREE);
2108 }
2109
2110 /* Make an expression to refer to the COMPONENT field of structure or
2111    union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  LOC is the
2112    location of the COMPONENT_REF.  */
2113
2114 tree
2115 build_component_ref (location_t loc, tree datum, tree component)
2116 {
2117   tree type = TREE_TYPE (datum);
2118   enum tree_code code = TREE_CODE (type);
2119   tree field = NULL;
2120   tree ref;
2121   bool datum_lvalue = lvalue_p (datum);
2122
2123   if (!objc_is_public (datum, component))
2124     return error_mark_node;
2125
2126   /* Detect Objective-C property syntax object.property.  */
2127   if (c_dialect_objc ()
2128       && (ref = objc_maybe_build_component_ref (datum, component)))
2129     return ref;
2130
2131   /* See if there is a field or component with name COMPONENT.  */
2132
2133   if (code == RECORD_TYPE || code == UNION_TYPE)
2134     {
2135       if (!COMPLETE_TYPE_P (type))
2136         {
2137           c_incomplete_type_error (NULL_TREE, type);
2138           return error_mark_node;
2139         }
2140
2141       field = lookup_field (type, component);
2142
2143       if (!field)
2144         {
2145           error_at (loc, "%qT has no member named %qE", type, component);
2146           return error_mark_node;
2147         }
2148
2149       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
2150          This might be better solved in future the way the C++ front
2151          end does it - by giving the anonymous entities each a
2152          separate name and type, and then have build_component_ref
2153          recursively call itself.  We can't do that here.  */
2154       do
2155         {
2156           tree subdatum = TREE_VALUE (field);
2157           int quals;
2158           tree subtype;
2159           bool use_datum_quals;
2160
2161           if (TREE_TYPE (subdatum) == error_mark_node)
2162             return error_mark_node;
2163
2164           /* If this is an rvalue, it does not have qualifiers in C
2165              standard terms and we must avoid propagating such
2166              qualifiers down to a non-lvalue array that is then
2167              converted to a pointer.  */
2168           use_datum_quals = (datum_lvalue
2169                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
2170
2171           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
2172           if (use_datum_quals)
2173             quals |= TYPE_QUALS (TREE_TYPE (datum));
2174           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
2175
2176           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
2177                         NULL_TREE);
2178           SET_EXPR_LOCATION (ref, loc);
2179           if (TREE_READONLY (subdatum)
2180               || (use_datum_quals && TREE_READONLY (datum)))
2181             TREE_READONLY (ref) = 1;
2182           if (TREE_THIS_VOLATILE (subdatum)
2183               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
2184             TREE_THIS_VOLATILE (ref) = 1;
2185
2186           if (TREE_DEPRECATED (subdatum))
2187             warn_deprecated_use (subdatum, NULL_TREE);
2188
2189           datum = ref;
2190
2191           field = TREE_CHAIN (field);
2192         }
2193       while (field);
2194
2195       return ref;
2196     }
2197   else if (code != ERROR_MARK)
2198     error_at (loc,
2199               "request for member %qE in something not a structure or union",
2200               component);
2201
2202   return error_mark_node;
2203 }
2204 \f
2205 /* Given an expression PTR for a pointer, return an expression
2206    for the value pointed to.
2207    ERRORSTRING is the name of the operator to appear in error messages.
2208
2209    LOC is the location to use for the generated tree.  */
2210
2211 tree
2212 build_indirect_ref (location_t loc, tree ptr, ref_operator errstring)
2213 {
2214   tree pointer = default_conversion (ptr);
2215   tree type = TREE_TYPE (pointer);
2216   tree ref;
2217
2218   if (TREE_CODE (type) == POINTER_TYPE)
2219     {
2220       if (CONVERT_EXPR_P (pointer)
2221           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2222         {
2223           /* If a warning is issued, mark it to avoid duplicates from
2224              the backend.  This only needs to be done at
2225              warn_strict_aliasing > 2.  */
2226           if (warn_strict_aliasing > 2)
2227             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2228                                          type, TREE_OPERAND (pointer, 0)))
2229               TREE_NO_WARNING (pointer) = 1;
2230         }
2231
2232       if (TREE_CODE (pointer) == ADDR_EXPR
2233           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2234               == TREE_TYPE (type)))
2235         {
2236           ref = TREE_OPERAND (pointer, 0);
2237           protected_set_expr_location (ref, loc);
2238           return ref;
2239         }
2240       else
2241         {
2242           tree t = TREE_TYPE (type);
2243
2244           ref = build1 (INDIRECT_REF, t, pointer);
2245
2246           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2247             {
2248               error_at (loc, "dereferencing pointer to incomplete type");
2249               return error_mark_node;
2250             }
2251           if (VOID_TYPE_P (t) && c_inhibit_evaluation_warnings == 0)
2252             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2253
2254           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2255              so that we get the proper error message if the result is used
2256              to assign to.  Also, &* is supposed to be a no-op.
2257              And ANSI C seems to specify that the type of the result
2258              should be the const type.  */
2259           /* A de-reference of a pointer to const is not a const.  It is valid
2260              to change it via some other pointer.  */
2261           TREE_READONLY (ref) = TYPE_READONLY (t);
2262           TREE_SIDE_EFFECTS (ref)
2263             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2264           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2265           protected_set_expr_location (ref, loc);
2266           return ref;
2267         }
2268     }
2269   else if (TREE_CODE (pointer) != ERROR_MARK)
2270     switch (errstring)
2271       {
2272          case RO_ARRAY_INDEXING:
2273            error_at (loc,
2274                      "invalid type argument of array indexing (have %qT)",
2275                      type);
2276            break;
2277          case RO_UNARY_STAR:
2278            error_at (loc,
2279                      "invalid type argument of unary %<*%> (have %qT)",
2280                      type);
2281            break;
2282          case RO_ARROW:
2283            error_at (loc,
2284                      "invalid type argument of %<->%> (have %qT)",
2285                      type);
2286            break;
2287          default:
2288            gcc_unreachable ();
2289       }
2290   return error_mark_node;
2291 }
2292
2293 /* This handles expressions of the form "a[i]", which denotes
2294    an array reference.
2295
2296    This is logically equivalent in C to *(a+i), but we may do it differently.
2297    If A is a variable or a member, we generate a primitive ARRAY_REF.
2298    This avoids forcing the array out of registers, and can work on
2299    arrays that are not lvalues (for example, members of structures returned
2300    by functions).
2301
2302    For vector types, allow vector[i] but not i[vector], and create
2303    *(((type*)&vectortype) + i) for the expression.
2304
2305    LOC is the location to use for the returned expression.  */
2306
2307 tree
2308 build_array_ref (location_t loc, tree array, tree index)
2309 {
2310   tree ret;
2311   bool swapped = false;
2312   if (TREE_TYPE (array) == error_mark_node
2313       || TREE_TYPE (index) == error_mark_node)
2314     return error_mark_node;
2315
2316   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2317       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE
2318       /* Allow vector[index] but not index[vector].  */
2319       && TREE_CODE (TREE_TYPE (array)) != VECTOR_TYPE)
2320     {
2321       tree temp;
2322       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2323           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2324         {
2325           error_at (loc,
2326             "subscripted value is neither array nor pointer nor vector");
2327
2328           return error_mark_node;
2329         }
2330       temp = array;
2331       array = index;
2332       index = temp;
2333       swapped = true;
2334     }
2335
2336   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2337     {
2338       error_at (loc, "array subscript is not an integer");
2339       return error_mark_node;
2340     }
2341
2342   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2343     {
2344       error_at (loc, "subscripted value is pointer to function");
2345       return error_mark_node;
2346     }
2347
2348   /* ??? Existing practice has been to warn only when the char
2349      index is syntactically the index, not for char[array].  */
2350   if (!swapped)
2351      warn_array_subscript_with_type_char (index);
2352
2353   /* Apply default promotions *after* noticing character types.  */
2354   index = default_conversion (index);
2355
2356   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2357
2358   /* For vector[index], convert the vector to a
2359      pointer of the underlying type.  */
2360   if (TREE_CODE (TREE_TYPE (array)) == VECTOR_TYPE)
2361     {
2362       tree type = TREE_TYPE (array);
2363       tree type1;
2364
2365       if (TREE_CODE (index) == INTEGER_CST)
2366         if (!host_integerp (index, 1)
2367             || ((unsigned HOST_WIDE_INT) tree_low_cst (index, 1)
2368                >= TYPE_VECTOR_SUBPARTS (TREE_TYPE (array))))
2369           warning_at (loc, OPT_Warray_bounds, "index value is out of bound");
2370
2371       c_common_mark_addressable_vec (array);
2372       type = build_qualified_type (TREE_TYPE (type), TYPE_QUALS (type));
2373       type = build_pointer_type (type);
2374       type1 = build_pointer_type (TREE_TYPE (array));
2375       array = build1 (ADDR_EXPR, type1, array);
2376       array = convert (type, array);
2377     }
2378
2379   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2380     {
2381       tree rval, type;
2382
2383       /* An array that is indexed by a non-constant
2384          cannot be stored in a register; we must be able to do
2385          address arithmetic on its address.
2386          Likewise an array of elements of variable size.  */
2387       if (TREE_CODE (index) != INTEGER_CST
2388           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2389               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2390         {
2391           if (!c_mark_addressable (array))
2392             return error_mark_node;
2393         }
2394       /* An array that is indexed by a constant value which is not within
2395          the array bounds cannot be stored in a register either; because we
2396          would get a crash in store_bit_field/extract_bit_field when trying
2397          to access a non-existent part of the register.  */
2398       if (TREE_CODE (index) == INTEGER_CST
2399           && TYPE_DOMAIN (TREE_TYPE (array))
2400           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2401         {
2402           if (!c_mark_addressable (array))
2403             return error_mark_node;
2404         }
2405
2406       if (pedantic)
2407         {
2408           tree foo = array;
2409           while (TREE_CODE (foo) == COMPONENT_REF)
2410             foo = TREE_OPERAND (foo, 0);
2411           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2412             pedwarn (loc, OPT_pedantic,
2413                      "ISO C forbids subscripting %<register%> array");
2414           else if (!flag_isoc99 && !lvalue_p (foo))
2415             pedwarn (loc, OPT_pedantic,
2416                      "ISO C90 forbids subscripting non-lvalue array");
2417         }
2418
2419       type = TREE_TYPE (TREE_TYPE (array));
2420       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2421       /* Array ref is const/volatile if the array elements are
2422          or if the array is.  */
2423       TREE_READONLY (rval)
2424         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2425             | TREE_READONLY (array));
2426       TREE_SIDE_EFFECTS (rval)
2427         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2428             | TREE_SIDE_EFFECTS (array));
2429       TREE_THIS_VOLATILE (rval)
2430         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2431             /* This was added by rms on 16 Nov 91.
2432                It fixes  vol struct foo *a;  a->elts[1]
2433                in an inline function.
2434                Hope it doesn't break something else.  */
2435             | TREE_THIS_VOLATILE (array));
2436       ret = require_complete_type (rval);
2437       protected_set_expr_location (ret, loc);
2438       return ret;
2439     }
2440   else
2441     {
2442       tree ar = default_conversion (array);
2443
2444       if (ar == error_mark_node)
2445         return ar;
2446
2447       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2448       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2449
2450       return build_indirect_ref
2451         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2452          RO_ARRAY_INDEXING);
2453     }
2454 }
2455 \f
2456 /* Build an external reference to identifier ID.  FUN indicates
2457    whether this will be used for a function call.  LOC is the source
2458    location of the identifier.  This sets *TYPE to the type of the
2459    identifier, which is not the same as the type of the returned value
2460    for CONST_DECLs defined as enum constants.  If the type of the
2461    identifier is not available, *TYPE is set to NULL.  */
2462 tree
2463 build_external_ref (location_t loc, tree id, int fun, tree *type)
2464 {
2465   tree ref;
2466   tree decl = lookup_name (id);
2467
2468   /* In Objective-C, an instance variable (ivar) may be preferred to
2469      whatever lookup_name() found.  */
2470   decl = objc_lookup_ivar (decl, id);
2471
2472   *type = NULL;
2473   if (decl && decl != error_mark_node)
2474     {
2475       ref = decl;
2476       *type = TREE_TYPE (ref);
2477     }
2478   else if (fun)
2479     /* Implicit function declaration.  */
2480     ref = implicitly_declare (loc, id);
2481   else if (decl == error_mark_node)
2482     /* Don't complain about something that's already been
2483        complained about.  */
2484     return error_mark_node;
2485   else
2486     {
2487       undeclared_variable (loc, id);
2488       return error_mark_node;
2489     }
2490
2491   if (TREE_TYPE (ref) == error_mark_node)
2492     return error_mark_node;
2493
2494   if (TREE_DEPRECATED (ref))
2495     warn_deprecated_use (ref, NULL_TREE);
2496
2497   /* Recursive call does not count as usage.  */
2498   if (ref != current_function_decl)
2499     {
2500       TREE_USED (ref) = 1;
2501     }
2502
2503   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2504     {
2505       if (!in_sizeof && !in_typeof)
2506         C_DECL_USED (ref) = 1;
2507       else if (DECL_INITIAL (ref) == 0
2508                && DECL_EXTERNAL (ref)
2509                && !TREE_PUBLIC (ref))
2510         record_maybe_used_decl (ref);
2511     }
2512
2513   if (TREE_CODE (ref) == CONST_DECL)
2514     {
2515       used_types_insert (TREE_TYPE (ref));
2516
2517       if (warn_cxx_compat
2518           && TREE_CODE (TREE_TYPE (ref)) == ENUMERAL_TYPE
2519           && C_TYPE_DEFINED_IN_STRUCT (TREE_TYPE (ref)))
2520         {
2521           warning_at (loc, OPT_Wc___compat,
2522                       ("enum constant defined in struct or union "
2523                        "is not visible in C++"));
2524           inform (DECL_SOURCE_LOCATION (ref), "enum constant defined here");
2525         }
2526
2527       ref = DECL_INITIAL (ref);
2528       TREE_CONSTANT (ref) = 1;
2529     }
2530   else if (current_function_decl != 0
2531            && !DECL_FILE_SCOPE_P (current_function_decl)
2532            && (TREE_CODE (ref) == VAR_DECL
2533                || TREE_CODE (ref) == PARM_DECL
2534                || TREE_CODE (ref) == FUNCTION_DECL))
2535     {
2536       tree context = decl_function_context (ref);
2537
2538       if (context != 0 && context != current_function_decl)
2539         DECL_NONLOCAL (ref) = 1;
2540     }
2541   /* C99 6.7.4p3: An inline definition of a function with external
2542      linkage ... shall not contain a reference to an identifier with
2543      internal linkage.  */
2544   else if (current_function_decl != 0
2545            && DECL_DECLARED_INLINE_P (current_function_decl)
2546            && DECL_EXTERNAL (current_function_decl)
2547            && VAR_OR_FUNCTION_DECL_P (ref)
2548            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2549            && ! TREE_PUBLIC (ref)
2550            && DECL_CONTEXT (ref) != current_function_decl)
2551     record_inline_static (loc, current_function_decl, ref,
2552                           csi_internal);
2553
2554   return ref;
2555 }
2556
2557 /* Record details of decls possibly used inside sizeof or typeof.  */
2558 struct maybe_used_decl
2559 {
2560   /* The decl.  */
2561   tree decl;
2562   /* The level seen at (in_sizeof + in_typeof).  */
2563   int level;
2564   /* The next one at this level or above, or NULL.  */
2565   struct maybe_used_decl *next;
2566 };
2567
2568 static struct maybe_used_decl *maybe_used_decls;
2569
2570 /* Record that DECL, an undefined static function reference seen
2571    inside sizeof or typeof, might be used if the operand of sizeof is
2572    a VLA type or the operand of typeof is a variably modified
2573    type.  */
2574
2575 static void
2576 record_maybe_used_decl (tree decl)
2577 {
2578   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2579   t->decl = decl;
2580   t->level = in_sizeof + in_typeof;
2581   t->next = maybe_used_decls;
2582   maybe_used_decls = t;
2583 }
2584
2585 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2586    USED is false, just discard them.  If it is true, mark them used
2587    (if no longer inside sizeof or typeof) or move them to the next
2588    level up (if still inside sizeof or typeof).  */
2589
2590 void
2591 pop_maybe_used (bool used)
2592 {
2593   struct maybe_used_decl *p = maybe_used_decls;
2594   int cur_level = in_sizeof + in_typeof;
2595   while (p && p->level > cur_level)
2596     {
2597       if (used)
2598         {
2599           if (cur_level == 0)
2600             C_DECL_USED (p->decl) = 1;
2601           else
2602             p->level = cur_level;
2603         }
2604       p = p->next;
2605     }
2606   if (!used || cur_level == 0)
2607     maybe_used_decls = p;
2608 }
2609
2610 /* Return the result of sizeof applied to EXPR.  */
2611
2612 struct c_expr
2613 c_expr_sizeof_expr (location_t loc, struct c_expr expr)
2614 {
2615   struct c_expr ret;
2616   if (expr.value == error_mark_node)
2617     {
2618       ret.value = error_mark_node;
2619       ret.original_code = ERROR_MARK;
2620       ret.original_type = NULL;
2621       pop_maybe_used (false);
2622     }
2623   else
2624     {
2625       bool expr_const_operands = true;
2626       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2627                                        &expr_const_operands);
2628       ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));
2629       ret.original_code = ERROR_MARK;
2630       ret.original_type = NULL;
2631       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2632         {
2633           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2634           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2635                               folded_expr, ret.value);
2636           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2637           SET_EXPR_LOCATION (ret.value, loc);
2638         }
2639       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2640     }
2641   return ret;
2642 }
2643
2644 /* Return the result of sizeof applied to T, a structure for the type
2645    name passed to sizeof (rather than the type itself).  LOC is the
2646    location of the original expression.  */
2647
2648 struct c_expr
2649 c_expr_sizeof_type (location_t loc, struct c_type_name *t)
2650 {
2651   tree type;
2652   struct c_expr ret;
2653   tree type_expr = NULL_TREE;
2654   bool type_expr_const = true;
2655   type = groktypename (t, &type_expr, &type_expr_const);
2656   ret.value = c_sizeof (loc, type);
2657   ret.original_code = ERROR_MARK;
2658   ret.original_type = NULL;
2659   if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST)
2660       && c_vla_type_p (type))
2661     {
2662       /* If the type is a [*] array, it is a VLA but is represented as
2663          having a size of zero.  In such a case we must ensure that
2664          the result of sizeof does not get folded to a constant by
2665          c_fully_fold, because if the size is evaluated the result is
2666          not constant and so constraints on zero or negative size
2667          arrays must not be applied when this sizeof call is inside
2668          another array declarator.  */
2669       if (!type_expr)
2670         type_expr = integer_zero_node;
2671       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2672                           type_expr, ret.value);
2673       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2674     }
2675   pop_maybe_used (type != error_mark_node
2676                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2677   return ret;
2678 }
2679
2680 /* Build a function call to function FUNCTION with parameters PARAMS.
2681    The function call is at LOC.
2682    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2683    TREE_VALUE of each node is a parameter-expression.
2684    FUNCTION's data type may be a function type or a pointer-to-function.  */
2685
2686 tree
2687 build_function_call (location_t loc, tree function, tree params)
2688 {
2689   VEC(tree,gc) *vec;
2690   tree ret;
2691
2692   vec = VEC_alloc (tree, gc, list_length (params));
2693   for (; params; params = TREE_CHAIN (params))
2694     VEC_quick_push (tree, vec, TREE_VALUE (params));
2695   ret = build_function_call_vec (loc, function, vec, NULL);
2696   VEC_free (tree, gc, vec);
2697   return ret;
2698 }
2699
2700 /* Build a function call to function FUNCTION with parameters PARAMS.
2701    ORIGTYPES, if not NULL, is a vector of types; each element is
2702    either NULL or the original type of the corresponding element in
2703    PARAMS.  The original type may differ from TREE_TYPE of the
2704    parameter for enums.  FUNCTION's data type may be a function type
2705    or pointer-to-function.  This function changes the elements of
2706    PARAMS.  */
2707
2708 tree
2709 build_function_call_vec (location_t loc, tree function, VEC(tree,gc) *params,
2710                          VEC(tree,gc) *origtypes)
2711 {
2712   tree fntype, fundecl = 0;
2713   tree name = NULL_TREE, result;
2714   tree tem;
2715   int nargs;
2716   tree *argarray;
2717
2718
2719   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2720   STRIP_TYPE_NOPS (function);
2721
2722   /* Convert anything with function type to a pointer-to-function.  */
2723   if (TREE_CODE (function) == FUNCTION_DECL)
2724     {
2725       /* Implement type-directed function overloading for builtins.
2726          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2727          handle all the type checking.  The result is a complete expression
2728          that implements this function call.  */
2729       tem = resolve_overloaded_builtin (loc, function, params);
2730       if (tem)
2731         return tem;
2732
2733       name = DECL_NAME (function);
2734       fundecl = function;
2735     }
2736   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2737     function = function_to_pointer_conversion (loc, function);
2738
2739   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2740      expressions, like those used for ObjC messenger dispatches.  */
2741   if (!VEC_empty (tree, params))
2742     function = objc_rewrite_function_call (function,
2743                                            VEC_index (tree, params, 0));
2744
2745   function = c_fully_fold (function, false, NULL);
2746
2747   fntype = TREE_TYPE (function);
2748
2749   if (TREE_CODE (fntype) == ERROR_MARK)
2750     return error_mark_node;
2751
2752   if (!(TREE_CODE (fntype) == POINTER_TYPE
2753         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2754     {
2755       error_at (loc, "called object %qE is not a function", function);
2756       return error_mark_node;
2757     }
2758
2759   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2760     current_function_returns_abnormally = 1;
2761
2762   /* fntype now gets the type of function pointed to.  */
2763   fntype = TREE_TYPE (fntype);
2764
2765   /* Convert the parameters to the types declared in the
2766      function prototype, or apply default promotions.  */
2767
2768   nargs = convert_arguments (TYPE_ARG_TYPES (fntype), params, origtypes,
2769                              function, fundecl);
2770   if (nargs < 0)
2771     return error_mark_node;
2772
2773   /* Check that the function is called through a compatible prototype.
2774      If it is not, replace the call by a trap, wrapped up in a compound
2775      expression if necessary.  This has the nice side-effect to prevent
2776      the tree-inliner from generating invalid assignment trees which may
2777      blow up in the RTL expander later.  */
2778   if (CONVERT_EXPR_P (function)
2779       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2780       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2781       && !comptypes (fntype, TREE_TYPE (tem)))
2782     {
2783       tree return_type = TREE_TYPE (fntype);
2784       tree trap = build_function_call (loc, built_in_decls[BUILT_IN_TRAP],
2785                                        NULL_TREE);
2786       int i;
2787
2788       /* This situation leads to run-time undefined behavior.  We can't,
2789          therefore, simply error unless we can prove that all possible
2790          executions of the program must execute the code.  */
2791       if (warning_at (loc, 0, "function called through a non-compatible type"))
2792         /* We can, however, treat "undefined" any way we please.
2793            Call abort to encourage the user to fix the program.  */
2794         inform (loc, "if this code is reached, the program will abort");
2795       /* Before the abort, allow the function arguments to exit or
2796          call longjmp.  */
2797       for (i = 0; i < nargs; i++)
2798         trap = build2 (COMPOUND_EXPR, void_type_node,
2799                        VEC_index (tree, params, i), trap);
2800
2801       if (VOID_TYPE_P (return_type))
2802         {
2803           if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
2804             pedwarn (loc, 0,
2805                      "function with qualified void return type called");
2806           return trap;
2807         }
2808       else
2809         {
2810           tree rhs;
2811
2812           if (AGGREGATE_TYPE_P (return_type))
2813             rhs = build_compound_literal (loc, return_type,
2814                                           build_constructor (return_type, 0),
2815                                           false);
2816           else
2817             rhs = build_zero_cst (return_type);
2818
2819           return require_complete_type (build2 (COMPOUND_EXPR, return_type,
2820                                                 trap, rhs));
2821         }
2822     }
2823
2824   argarray = VEC_address (tree, params);
2825
2826   /* Check that arguments to builtin functions match the expectations.  */
2827   if (fundecl
2828       && DECL_BUILT_IN (fundecl)
2829       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2830       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2831     return error_mark_node;
2832
2833   /* Check that the arguments to the function are valid.  */
2834   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2835                             TYPE_ARG_TYPES (fntype));
2836
2837   if (name != NULL_TREE
2838       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2839     {
2840       if (require_constant_value)
2841         result =
2842           fold_build_call_array_initializer_loc (loc, TREE_TYPE (fntype),
2843                                                  function, nargs, argarray);
2844       else
2845         result = fold_build_call_array_loc (loc, TREE_TYPE (fntype),
2846                                             function, nargs, argarray);
2847       if (TREE_CODE (result) == NOP_EXPR
2848           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2849         STRIP_TYPE_NOPS (result);
2850     }
2851   else
2852     result = build_call_array_loc (loc, TREE_TYPE (fntype),
2853                                    function, nargs, argarray);
2854
2855   if (VOID_TYPE_P (TREE_TYPE (result)))
2856     {
2857       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)
2858         pedwarn (loc, 0,
2859                  "function with qualified void return type called");
2860       return result;
2861     }
2862   return require_complete_type (result);
2863 }
2864 \f
2865 /* Convert the argument expressions in the vector VALUES
2866    to the types in the list TYPELIST.
2867
2868    If TYPELIST is exhausted, or when an element has NULL as its type,
2869    perform the default conversions.
2870
2871    ORIGTYPES is the original types of the expressions in VALUES.  This
2872    holds the type of enum values which have been converted to integral
2873    types.  It may be NULL.
2874
2875    FUNCTION is a tree for the called function.  It is used only for
2876    error messages, where it is formatted with %qE.
2877
2878    This is also where warnings about wrong number of args are generated.
2879
2880    Returns the actual number of arguments processed (which may be less
2881    than the length of VALUES in some error situations), or -1 on
2882    failure.  */
2883
2884 static int
2885 convert_arguments (tree typelist, VEC(tree,gc) *values,
2886                    VEC(tree,gc) *origtypes, tree function, tree fundecl)
2887 {
2888   tree typetail, val;
2889   unsigned int parmnum;
2890   bool error_args = false;
2891   const bool type_generic = fundecl
2892     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2893   bool type_generic_remove_excess_precision = false;
2894   tree selector;
2895
2896   /* Change pointer to function to the function itself for
2897      diagnostics.  */
2898   if (TREE_CODE (function) == ADDR_EXPR
2899       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2900     function = TREE_OPERAND (function, 0);
2901
2902   /* Handle an ObjC selector specially for diagnostics.  */
2903   selector = objc_message_selector ();
2904
2905   /* For type-generic built-in functions, determine whether excess
2906      precision should be removed (classification) or not
2907      (comparison).  */
2908   if (type_generic
2909       && DECL_BUILT_IN (fundecl)
2910       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2911     {
2912       switch (DECL_FUNCTION_CODE (fundecl))
2913         {
2914         case BUILT_IN_ISFINITE:
2915         case BUILT_IN_ISINF:
2916         case BUILT_IN_ISINF_SIGN:
2917         case BUILT_IN_ISNAN:
2918         case BUILT_IN_ISNORMAL:
2919         case BUILT_IN_FPCLASSIFY:
2920           type_generic_remove_excess_precision = true;
2921           break;
2922
2923         default:
2924           type_generic_remove_excess_precision = false;
2925           break;
2926         }
2927     }
2928
2929   /* Scan the given expressions and types, producing individual
2930      converted arguments.  */
2931
2932   for (typetail = typelist, parmnum = 0;
2933        VEC_iterate (tree, values, parmnum, val);
2934        ++parmnum)
2935     {
2936       tree type = typetail ? TREE_VALUE (typetail) : 0;
2937       tree valtype = TREE_TYPE (val);
2938       tree rname = function;
2939       int argnum = parmnum + 1;
2940       const char *invalid_func_diag;
2941       bool excess_precision = false;
2942       bool npc;
2943       tree parmval;
2944
2945       if (type == void_type_node)
2946         {
2947           if (selector)
2948             error_at (input_location,
2949                       "too many arguments to method %qE", selector);
2950           else
2951             error_at (input_location,
2952                       "too many arguments to function %qE", function);
2953
2954           if (fundecl && !DECL_BUILT_IN (fundecl))
2955             inform (DECL_SOURCE_LOCATION (fundecl), "declared here");
2956           return parmnum;
2957         }
2958
2959       if (selector && argnum > 2)
2960         {
2961           rname = selector;
2962           argnum -= 2;
2963         }
2964
2965       npc = null_pointer_constant_p (val);
2966
2967       /* If there is excess precision and a prototype, convert once to
2968          the required type rather than converting via the semantic
2969          type.  Likewise without a prototype a float value represented
2970          as long double should be converted once to double.  But for
2971          type-generic classification functions excess precision must
2972          be removed here.  */
2973       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2974           && (type || !type_generic || !type_generic_remove_excess_precision))
2975         {
2976           val = TREE_OPERAND (val, 0);
2977           excess_precision = true;
2978         }
2979       val = c_fully_fold (val, false, NULL);
2980       STRIP_TYPE_NOPS (val);
2981
2982       val = require_complete_type (val);
2983
2984       if (type != 0)
2985         {
2986           /* Formal parm type is specified by a function prototype.  */
2987
2988           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2989             {
2990               error ("type of formal parameter %d is incomplete", parmnum + 1);
2991               parmval = val;
2992             }
2993           else
2994             {
2995               tree origtype;
2996
2997               /* Optionally warn about conversions that
2998                  differ from the default conversions.  */
2999               if (warn_traditional_conversion || warn_traditional)
3000                 {
3001                   unsigned int formal_prec = TYPE_PRECISION (type);
3002
3003                   if (INTEGRAL_TYPE_P (type)
3004                       && TREE_CODE (valtype) == REAL_TYPE)
3005                     warning (0, "passing argument %d of %qE as integer "
3006                              "rather than floating due to prototype",
3007                              argnum, rname);
3008                   if (INTEGRAL_TYPE_P (type)
3009                       && TREE_CODE (valtype) == COMPLEX_TYPE)
3010                     warning (0, "passing argument %d of %qE as integer "
3011                              "rather than complex due to prototype",
3012                              argnum, rname);
3013                   else if (TREE_CODE (type) == COMPLEX_TYPE
3014                            && TREE_CODE (valtype) == REAL_TYPE)
3015                     warning (0, "passing argument %d of %qE as complex "
3016                              "rather than floating due to prototype",
3017                              argnum, rname);
3018                   else if (TREE_CODE (type) == REAL_TYPE
3019                            && INTEGRAL_TYPE_P (valtype))
3020                     warning (0, "passing argument %d of %qE as floating "
3021                              "rather than integer due to prototype",
3022                              argnum, rname);
3023                   else if (TREE_CODE (type) == COMPLEX_TYPE
3024                            && INTEGRAL_TYPE_P (valtype))
3025                     warning (0, "passing argument %d of %qE as complex "
3026                              "rather than integer due to prototype",
3027                              argnum, rname);
3028                   else if (TREE_CODE (type) == REAL_TYPE
3029                            && TREE_CODE (valtype) == COMPLEX_TYPE)
3030                     warning (0, "passing argument %d of %qE as floating "
3031                              "rather than complex due to prototype",
3032                              argnum, rname);
3033                   /* ??? At some point, messages should be written about
3034                      conversions between complex types, but that's too messy
3035                      to do now.  */
3036                   else if (TREE_CODE (type) == REAL_TYPE
3037                            && TREE_CODE (valtype) == REAL_TYPE)
3038                     {
3039                       /* Warn if any argument is passed as `float',
3040                          since without a prototype it would be `double'.  */
3041                       if (formal_prec == TYPE_PRECISION (float_type_node)
3042                           && type != dfloat32_type_node)
3043                         warning (0, "passing argument %d of %qE as %<float%> "
3044                                  "rather than %<double%> due to prototype",
3045                                  argnum, rname);
3046
3047                       /* Warn if mismatch between argument and prototype
3048                          for decimal float types.  Warn of conversions with
3049                          binary float types and of precision narrowing due to
3050                          prototype. */
3051                       else if (type != valtype
3052                                && (type == dfloat32_type_node
3053                                    || type == dfloat64_type_node
3054                                    || type == dfloat128_type_node
3055                                    || valtype == dfloat32_type_node
3056                                    || valtype == dfloat64_type_node
3057                                    || valtype == dfloat128_type_node)
3058                                && (formal_prec
3059                                    <= TYPE_PRECISION (valtype)
3060                                    || (type == dfloat128_type_node
3061                                        && (valtype
3062                                            != dfloat64_type_node
3063                                            && (valtype
3064                                                != dfloat32_type_node)))
3065                                    || (type == dfloat64_type_node
3066                                        && (valtype
3067                                            != dfloat32_type_node))))
3068                         warning (0, "passing argument %d of %qE as %qT "
3069                                  "rather than %qT due to prototype",
3070                                  argnum, rname, type, valtype);
3071
3072                     }
3073                   /* Detect integer changing in width or signedness.
3074                      These warnings are only activated with
3075                      -Wtraditional-conversion, not with -Wtraditional.  */
3076                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
3077                            && INTEGRAL_TYPE_P (valtype))
3078                     {
3079                       tree would_have_been = default_conversion (val);
3080                       tree type1 = TREE_TYPE (would_have_been);
3081
3082                       if (TREE_CODE (type) == ENUMERAL_TYPE
3083                           && (TYPE_MAIN_VARIANT (type)
3084                               == TYPE_MAIN_VARIANT (valtype)))
3085                         /* No warning if function asks for enum
3086                            and the actual arg is that enum type.  */
3087                         ;
3088                       else if (formal_prec != TYPE_PRECISION (type1))
3089                         warning (OPT_Wtraditional_conversion,
3090                                  "passing argument %d of %qE "
3091                                  "with different width due to prototype",
3092                                  argnum, rname);
3093                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
3094                         ;
3095                       /* Don't complain if the formal parameter type
3096                          is an enum, because we can't tell now whether
3097                          the value was an enum--even the same enum.  */
3098                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
3099                         ;
3100                       else if (TREE_CODE (val) == INTEGER_CST
3101                                && int_fits_type_p (val, type))
3102                         /* Change in signedness doesn't matter
3103                            if a constant value is unaffected.  */
3104                         ;
3105                       /* If the value is extended from a narrower
3106                          unsigned type, it doesn't matter whether we
3107                          pass it as signed or unsigned; the value
3108                          certainly is the same either way.  */
3109                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
3110                                && TYPE_UNSIGNED (valtype))
3111                         ;
3112                       else if (TYPE_UNSIGNED (type))
3113                         warning (OPT_Wtraditional_conversion,
3114                                  "passing argument %d of %qE "
3115                                  "as unsigned due to prototype",
3116                                  argnum, rname);
3117                       else
3118                         warning (OPT_Wtraditional_conversion,
3119                                  "passing argument %d of %qE "
3120                                  "as signed due to prototype", argnum, rname);
3121                     }
3122                 }
3123
3124               /* Possibly restore an EXCESS_PRECISION_EXPR for the
3125                  sake of better warnings from convert_and_check.  */
3126               if (excess_precision)
3127                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
3128               origtype = (origtypes == NULL
3129                           ? NULL_TREE
3130                           : VEC_index (tree, origtypes, parmnum));
3131               parmval = convert_for_assignment (input_location, type, val,
3132                                                 origtype, ic_argpass, npc,
3133                                                 fundecl, function,
3134                                                 parmnum + 1);
3135
3136               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
3137                   && INTEGRAL_TYPE_P (type)
3138                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3139                 parmval = default_conversion (parmval);
3140             }
3141         }
3142       else if (TREE_CODE (valtype) == REAL_TYPE
3143                && (TYPE_PRECISION (valtype)
3144                    < TYPE_PRECISION (double_type_node))
3145                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
3146         {
3147           if (type_generic)
3148             parmval = val;
3149           else
3150             {
3151               /* Convert `float' to `double'.  */
3152               if (warn_double_promotion && !c_inhibit_evaluation_warnings)
3153                 warning (OPT_Wdouble_promotion,
3154                          "implicit conversion from %qT to %qT when passing "
3155                          "argument to function",
3156                          valtype, double_type_node);
3157               parmval = convert (double_type_node, val);
3158             }
3159         }
3160       else if (excess_precision && !type_generic)
3161         /* A "double" argument with excess precision being passed
3162            without a prototype or in variable arguments.  */
3163         parmval = convert (valtype, val);
3164       else if ((invalid_func_diag =
3165                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
3166         {
3167           error (invalid_func_diag);
3168           return -1;
3169         }
3170       else
3171         /* Convert `short' and `char' to full-size `int'.  */
3172         parmval = default_conversion (val);
3173
3174       VEC_replace (tree, values, parmnum, parmval);
3175       if (parmval == error_mark_node)
3176         error_args = true;
3177
3178       if (typetail)
3179         typetail = TREE_CHAIN (typetail);
3180     }
3181
3182   gcc_assert (parmnum == VEC_length (tree, values));
3183
3184   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
3185     {
3186       error_at (input_location,
3187                 "too few arguments to function %qE", function);
3188       if (fundecl && !DECL_BUILT_IN (fundecl))
3189         inform (DECL_SOURCE_LOCATION (fundecl), "declared here");
3190       return -1;
3191     }
3192
3193   return error_args ? -1 : (int) parmnum;
3194 }
3195 \f
3196 /* This is the entry point used by the parser to build unary operators
3197    in the input.  CODE, a tree_code, specifies the unary operator, and
3198    ARG is the operand.  For unary plus, the C parser currently uses
3199    CONVERT_EXPR for code.
3200
3201    LOC is the location to use for the tree generated.
3202 */
3203
3204 struct c_expr
3205 parser_build_unary_op (location_t loc, enum tree_code code, struct c_expr arg)
3206 {
3207   struct c_expr result;
3208
3209   result.value = build_unary_op (loc, code, arg.value, 0);
3210   result.original_code = code;
3211   result.original_type = NULL;
3212
3213   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
3214     overflow_warning (loc, result.value);
3215
3216   return result;
3217 }
3218
3219 /* This is the entry point used by the parser to build binary operators
3220    in the input.  CODE, a tree_code, specifies the binary operator, and
3221    ARG1 and ARG2 are the operands.  In addition to constructing the
3222    expression, we check for operands that were written with other binary
3223    operators in a way that is likely to confuse the user.
3224
3225    LOCATION is the location of the binary operator.  */
3226
3227 struct c_expr
3228 parser_build_binary_op (location_t location, enum tree_code code,
3229                         struct c_expr arg1, struct c_expr arg2)
3230 {
3231   struct c_expr result;
3232
3233   enum tree_code code1 = arg1.original_code;
3234   enum tree_code code2 = arg2.original_code;
3235   tree type1 = (arg1.original_type
3236                 ? arg1.original_type
3237                 : TREE_TYPE (arg1.value));
3238   tree type2 = (arg2.original_type
3239                 ? arg2.original_type
3240                 : TREE_TYPE (arg2.value));
3241
3242   result.value = build_binary_op (location, code,
3243                                   arg1.value, arg2.value, 1);
3244   result.original_code = code;
3245   result.original_type = NULL;
3246
3247   if (TREE_CODE (result.value) == ERROR_MARK)
3248     return result;
3249
3250   if (location != UNKNOWN_LOCATION)
3251     protected_set_expr_location (result.value, location);
3252
3253   /* Check for cases such as x+y<<z which users are likely
3254      to misinterpret.  */
3255   if (warn_parentheses)
3256     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
3257
3258   if (warn_logical_op)
3259     warn_logical_operator (input_location, code, TREE_TYPE (result.value),
3260                            code1, arg1.value, code2, arg2.value);
3261
3262   /* Warn about comparisons against string literals, with the exception
3263      of testing for equality or inequality of a string literal with NULL.  */
3264   if (code == EQ_EXPR || code == NE_EXPR)
3265     {
3266       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
3267           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
3268         warning_at (location, OPT_Waddress,
3269                     "comparison with string literal results in unspecified behavior");
3270     }
3271   else if (TREE_CODE_CLASS (code) == tcc_comparison
3272            && (code1 == STRING_CST || code2 == STRING_CST))
3273     warning_at (location, OPT_Waddress,
3274                 "comparison with string literal results in unspecified behavior");
3275
3276   if (TREE_OVERFLOW_P (result.value)
3277       && !TREE_OVERFLOW_P (arg1.value)
3278       && !TREE_OVERFLOW_P (arg2.value))
3279     overflow_warning (location, result.value);
3280
3281   /* Warn about comparisons of different enum types.  */
3282   if (warn_enum_compare
3283       && TREE_CODE_CLASS (code) == tcc_comparison
3284       && TREE_CODE (type1) == ENUMERAL_TYPE
3285       && TREE_CODE (type2) == ENUMERAL_TYPE
3286       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
3287     warning_at (location, OPT_Wenum_compare,
3288                 "comparison between %qT and %qT",
3289                 type1, type2);
3290
3291   return result;
3292 }
3293 \f
3294 /* Return a tree for the difference of pointers OP0 and OP1.
3295    The resulting tree has type int.  */
3296
3297 static tree
3298 pointer_diff (location_t loc, tree op0, tree op1)
3299 {
3300   tree restype = ptrdiff_type_node;
3301   tree result, inttype;
3302
3303   addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op0)));
3304   addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op1)));
3305   tree target_type = TREE_TYPE (TREE_TYPE (op0));
3306   tree con0, con1, lit0, lit1;
3307   tree orig_op1 = op1;
3308
3309   /* If the operands point into different address spaces, we need to
3310      explicitly convert them to pointers into the common address space
3311      before we can subtract the numerical address values.  */
3312   if (as0 != as1)
3313     {
3314       addr_space_t as_common;
3315       tree common_type;
3316
3317       /* Determine the common superset address space.  This is guaranteed
3318          to exist because the caller verified that comp_target_types
3319          returned non-zero.  */
3320       if (!addr_space_superset (as0, as1, &as_common))
3321         gcc_unreachable ();
3322
3323       common_type = common_pointer_type (TREE_TYPE (op0), TREE_TYPE (op1));
3324       op0 = convert (common_type, op0);
3325       op1 = convert (common_type, op1);
3326     }
3327
3328   /* Determine integer type to perform computations in.  This will usually
3329      be the same as the result type (ptrdiff_t), but may need to be a wider
3330      type if pointers for the address space are wider than ptrdiff_t.  */
3331   if (TYPE_PRECISION (restype) < TYPE_PRECISION (TREE_TYPE (op0)))
3332     inttype = lang_hooks.types.type_for_size
3333                 (TYPE_PRECISION (TREE_TYPE (op0)), 0);
3334   else
3335     inttype = restype;
3336
3337
3338   if (TREE_CODE (target_type) == VOID_TYPE)
3339     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3340              "pointer of type %<void *%> used in subtraction");
3341   if (TREE_CODE (target_type) == FUNCTION_TYPE)
3342     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3343              "pointer to a function used in subtraction");
3344
3345   /* If the conversion to ptrdiff_type does anything like widening or
3346      converting a partial to an integral mode, we get a convert_expression
3347      that is in the way to do any simplifications.
3348      (fold-const.c doesn't know that the extra bits won't be needed.
3349      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
3350      different mode in place.)
3351      So first try to find a common term here 'by hand'; we want to cover
3352      at least the cases that occur in legal static initializers.  */
3353   if (CONVERT_EXPR_P (op0)
3354       && (TYPE_PRECISION (TREE_TYPE (op0))
3355           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
3356     con0 = TREE_OPERAND (op0, 0);
3357   else
3358     con0 = op0;
3359   if (CONVERT_EXPR_P (op1)
3360       && (TYPE_PRECISION (TREE_TYPE (op1))
3361           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
3362     con1 = TREE_OPERAND (op1, 0);
3363   else
3364     con1 = op1;
3365
3366   if (TREE_CODE (con0) == PLUS_EXPR)
3367     {
3368       lit0 = TREE_OPERAND (con0, 1);
3369       con0 = TREE_OPERAND (con0, 0);
3370     }
3371   else
3372     lit0 = integer_zero_node;
3373
3374   if (TREE_CODE (con1) == PLUS_EXPR)
3375     {
3376       lit1 = TREE_OPERAND (con1, 1);
3377       con1 = TREE_OPERAND (con1, 0);
3378     }
3379   else
3380     lit1 = integer_zero_node;
3381
3382   if (operand_equal_p (con0, con1, 0))
3383     {
3384       op0 = lit0;
3385       op1 = lit1;
3386     }
3387
3388
3389   /* First do the subtraction as integers;
3390      then drop through to build the divide operator.
3391      Do not do default conversions on the minus operator
3392      in case restype is a short type.  */
3393
3394   op0 = build_binary_op (loc,
3395                          MINUS_EXPR, convert (inttype, op0),
3396                          convert (inttype, op1), 0);
3397   /* This generates an error if op1 is pointer to incomplete type.  */
3398   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3399     error_at (loc, "arithmetic on pointer to an incomplete type");
3400
3401   /* This generates an error if op0 is pointer to incomplete type.  */
3402   op1 = c_size_in_bytes (target_type);
3403
3404   /* Divide by the size, in easiest possible way.  */
3405   result = fold_build2_loc (loc, EXACT_DIV_EXPR, inttype,
3406                             op0, convert (inttype, op1));
3407
3408   /* Convert to final result type if necessary.  */
3409   return convert (restype, result);
3410 }
3411 \f
3412 /* Construct and perhaps optimize a tree representation
3413    for a unary operation.  CODE, a tree_code, specifies the operation
3414    and XARG is the operand.
3415    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3416    the default promotions (such as from short to int).
3417    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3418    allows non-lvalues; this is only used to handle conversion of non-lvalue
3419    arrays to pointers in C99.
3420
3421    LOCATION is the location of the operator.  */
3422
3423 tree
3424 build_unary_op (location_t location,
3425                 enum tree_code code, tree xarg, int flag)
3426 {
3427   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3428   tree arg = xarg;
3429   tree argtype = 0;
3430   enum tree_code typecode;
3431   tree val;
3432   tree ret = error_mark_node;
3433   tree eptype = NULL_TREE;
3434   int noconvert = flag;
3435   const char *invalid_op_diag;
3436   bool int_operands;
3437
3438   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3439   if (int_operands)
3440     arg = remove_c_maybe_const_expr (arg);
3441
3442   if (code != ADDR_EXPR)
3443     arg = require_complete_type (arg);
3444
3445   typecode = TREE_CODE (TREE_TYPE (arg));
3446   if (typecode == ERROR_MARK)
3447     return error_mark_node;
3448   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3449     typecode = INTEGER_TYPE;
3450
3451   if ((invalid_op_diag
3452        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3453     {
3454       error_at (location, invalid_op_diag);
3455       return error_mark_node;
3456     }
3457
3458   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3459     {
3460       eptype = TREE_TYPE (arg);
3461       arg = TREE_OPERAND (arg, 0);
3462     }
3463
3464   switch (code)
3465     {
3466     case CONVERT_EXPR:
3467       /* This is used for unary plus, because a CONVERT_EXPR
3468          is enough to prevent anybody from looking inside for
3469          associativity, but won't generate any code.  */
3470       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3471             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3472             || typecode == VECTOR_TYPE))
3473         {
3474           error_at (location, "wrong type argument to unary plus");
3475           return error_mark_node;
3476         }
3477       else if (!noconvert)
3478         arg = default_conversion (arg);
3479       arg = non_lvalue_loc (location, arg);
3480       break;
3481
3482     case NEGATE_EXPR:
3483       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3484             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3485             || typecode == VECTOR_TYPE))
3486         {
3487           error_at (location, "wrong type argument to unary minus");
3488           return error_mark_node;
3489         }
3490       else if (!noconvert)
3491         arg = default_conversion (arg);
3492       break;
3493
3494     case BIT_NOT_EXPR:
3495       /* ~ works on integer types and non float vectors. */
3496       if (typecode == INTEGER_TYPE
3497           || (typecode == VECTOR_TYPE
3498               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3499         {
3500           if (!noconvert)
3501             arg = default_conversion (arg);
3502         }
3503       else if (typecode == COMPLEX_TYPE)
3504         {
3505           code = CONJ_EXPR;
3506           pedwarn (location, OPT_pedantic,
3507                    "ISO C does not support %<~%> for complex conjugation");
3508           if (!noconvert)
3509             arg = default_conversion (arg);
3510         }
3511       else
3512         {
3513           error_at (location, "wrong type argument to bit-complement");
3514           return error_mark_node;
3515         }
3516       break;
3517
3518     case ABS_EXPR:
3519       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3520         {
3521           error_at (location, "wrong type argument to abs");
3522           return error_mark_node;
3523         }
3524       else if (!noconvert)
3525         arg = default_conversion (arg);
3526       break;
3527
3528     case CONJ_EXPR:
3529       /* Conjugating a real value is a no-op, but allow it anyway.  */
3530       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3531             || typecode == COMPLEX_TYPE))
3532         {
3533           error_at (location, "wrong type argument to conjugation");
3534           return error_mark_node;
3535         }
3536       else if (!noconvert)
3537         arg = default_conversion (arg);
3538       break;
3539
3540     case TRUTH_NOT_EXPR:
3541       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3542           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3543           && typecode != COMPLEX_TYPE)
3544         {
3545           error_at (location,
3546                     "wrong type argument to unary exclamation mark");
3547           return error_mark_node;
3548         }
3549       arg = c_objc_common_truthvalue_conversion (location, arg);
3550       ret = invert_truthvalue_loc (location, arg);
3551       /* If the TRUTH_NOT_EXPR has been folded, reset the location.  */
3552       if (EXPR_P (ret) && EXPR_HAS_LOCATION (ret))
3553         location = EXPR_LOCATION (ret);
3554       goto return_build_unary_op;
3555
3556     case REALPART_EXPR:
3557     case IMAGPART_EXPR:
3558       ret = build_real_imag_expr (location, code, arg);
3559       if (ret == error_mark_node)
3560         return error_mark_node;
3561       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3562         eptype = TREE_TYPE (eptype);
3563       goto return_build_unary_op;
3564
3565     case PREINCREMENT_EXPR:
3566     case POSTINCREMENT_EXPR:
3567     case PREDECREMENT_EXPR:
3568     case POSTDECREMENT_EXPR:
3569
3570       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3571         {
3572           tree inner = build_unary_op (location, code,
3573                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3574           if (inner == error_mark_node)
3575             return error_mark_node;
3576           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3577                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3578           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3579           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3580           goto return_build_unary_op;
3581         }
3582
3583       /* Complain about anything that is not a true lvalue.  In
3584          Objective-C, skip this check for property_refs.  */
3585       if (!objc_is_property_ref (arg)
3586           && !lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3587                                      || code == POSTINCREMENT_EXPR)
3588                                     ? lv_increment
3589                                     : lv_decrement)))
3590         return error_mark_node;
3591
3592       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3593         {
3594           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3595             warning_at (location, OPT_Wc___compat,
3596                         "increment of enumeration value is invalid in C++");
3597           else
3598             warning_at (location, OPT_Wc___compat,
3599                         "decrement of enumeration value is invalid in C++");
3600         }
3601
3602       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3603       arg = c_fully_fold (arg, false, NULL);
3604
3605       /* Increment or decrement the real part of the value,
3606          and don't change the imaginary part.  */
3607       if (typecode == COMPLEX_TYPE)
3608         {
3609           tree real, imag;
3610
3611           pedwarn (location, OPT_pedantic,
3612                    "ISO C does not support %<++%> and %<--%> on complex types");
3613
3614           arg = stabilize_reference (arg);
3615           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3616           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3617           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3618           if (real == error_mark_node || imag == error_mark_node)
3619             return error_mark_node;
3620           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3621                         real, imag);
3622           goto return_build_unary_op;
3623         }
3624
3625       /* Report invalid types.  */
3626
3627       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3628           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3629         {
3630           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3631             error_at (location, "wrong type argument to increment");
3632           else
3633             error_at (location, "wrong type argument to decrement");
3634
3635           return error_mark_node;
3636         }
3637
3638       {
3639         tree inc;
3640
3641         argtype = TREE_TYPE (arg);
3642
3643         /* Compute the increment.  */
3644
3645         if (typecode == POINTER_TYPE)
3646           {
3647             /* If pointer target is an undefined struct,
3648                we just cannot know how to do the arithmetic.  */
3649             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3650               {
3651                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3652                   error_at (location,
3653                             "increment of pointer to unknown structure");
3654                 else
3655                   error_at (location,
3656                             "decrement of pointer to unknown structure");
3657               }
3658             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3659                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3660               {
3661                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3662                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3663                            "wrong type argument to increment");
3664                 else
3665                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3666                            "wrong type argument to decrement");
3667               }
3668
3669             inc = c_size_in_bytes (TREE_TYPE (argtype));
3670             inc = fold_convert_loc (location, sizetype, inc);
3671           }
3672         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3673           {
3674             /* For signed fract types, we invert ++ to -- or
3675                -- to ++, and change inc from 1 to -1, because
3676                it is not possible to represent 1 in signed fract constants.
3677                For unsigned fract types, the result always overflows and
3678                we get an undefined (original) or the maximum value.  */
3679             if (code == PREINCREMENT_EXPR)
3680               code = PREDECREMENT_EXPR;
3681             else if (code == PREDECREMENT_EXPR)
3682               code = PREINCREMENT_EXPR;
3683             else if (code == POSTINCREMENT_EXPR)
3684               code = POSTDECREMENT_EXPR;
3685             else /* code == POSTDECREMENT_EXPR  */
3686               code = POSTINCREMENT_EXPR;
3687
3688             inc = integer_minus_one_node;
3689             inc = convert (argtype, inc);
3690           }
3691         else
3692           {
3693             inc = integer_one_node;
3694             inc = convert (argtype, inc);
3695           }
3696
3697         /* If 'arg' is an Objective-C PROPERTY_REF expression, then we
3698            need to ask Objective-C to build the increment or decrement
3699            expression for it.  */
3700         if (objc_is_property_ref (arg))
3701           return objc_build_incr_expr_for_property_ref (location, code,
3702                                                         arg, inc);
3703
3704         /* Report a read-only lvalue.  */
3705         if (TYPE_READONLY (argtype))
3706           {
3707             readonly_error (arg,
3708                             ((code == PREINCREMENT_EXPR
3709                               || code == POSTINCREMENT_EXPR)
3710                              ? lv_increment : lv_decrement));
3711             return error_mark_node;
3712           }
3713         else if (TREE_READONLY (arg))
3714           readonly_warning (arg,
3715                             ((code == PREINCREMENT_EXPR
3716                               || code == POSTINCREMENT_EXPR)
3717                              ? lv_increment : lv_decrement));
3718
3719         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3720           val = boolean_increment (code, arg);
3721         else
3722           val = build2 (code, TREE_TYPE (arg), arg, inc);
3723         TREE_SIDE_EFFECTS (val) = 1;
3724         if (TREE_CODE (val) != code)
3725           TREE_NO_WARNING (val) = 1;
3726         ret = val;
3727         goto return_build_unary_op;
3728       }
3729
3730     case ADDR_EXPR:
3731       /* Note that this operation never does default_conversion.  */
3732
3733       /* The operand of unary '&' must be an lvalue (which excludes
3734          expressions of type void), or, in C99, the result of a [] or
3735          unary '*' operator.  */
3736       if (VOID_TYPE_P (TREE_TYPE (arg))
3737           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3738           && (TREE_CODE (arg) != INDIRECT_REF
3739               || !flag_isoc99))
3740         pedwarn (location, 0, "taking address of expression of type %<void%>");
3741
3742       /* Let &* cancel out to simplify resulting code.  */
3743       if (TREE_CODE (arg) == INDIRECT_REF)
3744         {
3745           /* Don't let this be an lvalue.  */
3746           if (lvalue_p (TREE_OPERAND (arg, 0)))
3747             return non_lvalue_loc (location, TREE_OPERAND (arg, 0));
3748           ret = TREE_OPERAND (arg, 0);
3749           goto return_build_unary_op;
3750         }
3751
3752       /* For &x[y], return x+y */
3753       if (TREE_CODE (arg) == ARRAY_REF)
3754         {
3755           tree op0 = TREE_OPERAND (arg, 0);
3756           if (!c_mark_addressable (op0))
3757             return error_mark_node;
3758           return build_binary_op (location, PLUS_EXPR,
3759                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3760                                    ? array_to_pointer_conversion (location,
3761                                                                   op0)
3762                                    : op0),
3763                                   TREE_OPERAND (arg, 1), 1);
3764         }
3765
3766       /* Anything not already handled and not a true memory reference
3767          or a non-lvalue array is an error.  */
3768       else if (typecode != FUNCTION_TYPE && !flag
3769                && !lvalue_or_else (arg, lv_addressof))
3770         return error_mark_node;
3771
3772       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3773          folding later.  */
3774       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3775         {
3776           tree inner = build_unary_op (location, code,
3777                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3778           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3779                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3780           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3781           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3782             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3783           goto return_build_unary_op;
3784         }
3785
3786       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3787       argtype = TREE_TYPE (arg);
3788
3789       /* If the lvalue is const or volatile, merge that into the type
3790          to which the address will point.  This should only be needed
3791          for function types.  */
3792       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3793           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3794         {
3795           int orig_quals = TYPE_QUALS (strip_array_types (argtype));
3796           int quals = orig_quals;
3797
3798           if (TREE_READONLY (arg))
3799             quals |= TYPE_QUAL_CONST;
3800           if (TREE_THIS_VOLATILE (arg))
3801             quals |= TYPE_QUAL_VOLATILE;
3802
3803           gcc_assert (quals == orig_quals
3804                       || TREE_CODE (argtype) == FUNCTION_TYPE);
3805
3806           argtype = c_build_qualified_type (argtype, quals);
3807         }
3808
3809       if (!c_mark_addressable (arg))
3810         return error_mark_node;
3811
3812       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3813                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3814
3815       argtype = build_pointer_type (argtype);
3816
3817       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3818          when we have proper support for integer constant expressions.  */
3819       val = get_base_address (arg);
3820       if (val && TREE_CODE (val) == INDIRECT_REF
3821           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3822         {
3823           tree op0 = fold_convert_loc (location, sizetype,
3824                                        fold_offsetof (arg, val)), op1;
3825
3826           op1 = fold_convert_loc (location, argtype, TREE_OPERAND (val, 0));
3827           ret = fold_build2_loc (location, POINTER_PLUS_EXPR, argtype, op1, op0);
3828           goto return_build_unary_op;
3829         }
3830
3831       val = build1 (ADDR_EXPR, argtype, arg);
3832
3833       ret = val;
3834       goto return_build_unary_op;
3835
3836     default:
3837       gcc_unreachable ();
3838     }
3839
3840   if (argtype == 0)
3841     argtype = TREE_TYPE (arg);
3842   if (TREE_CODE (arg) == INTEGER_CST)
3843     ret = (require_constant_value
3844            ? fold_build1_initializer_loc (location, code, argtype, arg)
3845            : fold_build1_loc (location, code, argtype, arg));
3846   else
3847     ret = build1 (code, argtype, arg);
3848  return_build_unary_op:
3849   gcc_assert (ret != error_mark_node);
3850   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3851       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3852     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3853   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3854     ret = note_integer_operands (ret);
3855   if (eptype)
3856     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3857   protected_set_expr_location (ret, location);
3858   return ret;
3859 }
3860
3861 /* Return nonzero if REF is an lvalue valid for this language.
3862    Lvalues can be assigned, unless their type has TYPE_READONLY.
3863    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3864
3865 bool
3866 lvalue_p (const_tree ref)
3867 {
3868   const enum tree_code code = TREE_CODE (ref);
3869
3870   switch (code)
3871     {
3872     case REALPART_EXPR:
3873     case IMAGPART_EXPR:
3874     case COMPONENT_REF:
3875       return lvalue_p (TREE_OPERAND (ref, 0));
3876
3877     case C_MAYBE_CONST_EXPR:
3878       return lvalue_p (TREE_OPERAND (ref, 1));
3879
3880     case COMPOUND_LITERAL_EXPR:
3881     case STRING_CST:
3882       return 1;
3883
3884     case INDIRECT_REF:
3885     case ARRAY_REF:
3886     case VAR_DECL:
3887     case PARM_DECL:
3888     case RESULT_DECL:
3889     case ERROR_MARK:
3890       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3891               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3892
3893     case BIND_EXPR:
3894       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3895
3896     default:
3897       return 0;
3898     }
3899 }
3900 \f
3901 /* Give an error for storing in something that is 'const'.  */
3902
3903 static void
3904 readonly_error (tree arg, enum lvalue_use use)
3905 {
3906   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3907               || use == lv_asm);
3908   /* Using this macro rather than (for example) arrays of messages
3909      ensures that all the format strings are checked at compile
3910      time.  */
3911 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3912                                    : (use == lv_increment ? (I)         \
3913                                    : (use == lv_decrement ? (D) : (AS))))
3914   if (TREE_CODE (arg) == COMPONENT_REF)
3915     {
3916       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3917         readonly_error (TREE_OPERAND (arg, 0), use);
3918       else
3919         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3920                              G_("increment of read-only member %qD"),
3921                              G_("decrement of read-only member %qD"),
3922                              G_("read-only member %qD used as %<asm%> output")),
3923                TREE_OPERAND (arg, 1));
3924     }
3925   else if (TREE_CODE (arg) == VAR_DECL)
3926     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3927                          G_("increment of read-only variable %qD"),
3928                          G_("decrement of read-only variable %qD"),
3929                          G_("read-only variable %qD used as %<asm%> output")),
3930            arg);
3931   else
3932     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3933                          G_("increment of read-only location %qE"),
3934                          G_("decrement of read-only location %qE"),
3935                          G_("read-only location %qE used as %<asm%> output")),
3936            arg);
3937 }
3938
3939 /* Give a warning for storing in something that is read-only in GCC
3940    terms but not const in ISO C terms.  */
3941
3942 static void
3943 readonly_warning (tree arg, enum lvalue_use use)
3944 {
3945   switch (use)
3946     {
3947     case lv_assign:
3948       warning (0, "assignment of read-only location %qE", arg);
3949       break;
3950     case lv_increment:
3951       warning (0, "increment of read-only location %qE", arg);
3952       break;
3953     case lv_decrement:
3954       warning (0, "decrement of read-only location %qE", arg);
3955       break;
3956     default:
3957       gcc_unreachable ();
3958     }
3959   return;
3960 }
3961
3962
3963 /* Return nonzero if REF is an lvalue valid for this language;
3964    otherwise, print an error message and return zero.  USE says
3965    how the lvalue is being used and so selects the error message.  */
3966
3967 static int
3968 lvalue_or_else (const_tree ref, enum lvalue_use use)
3969 {
3970   int win = lvalue_p (ref);
3971
3972   if (!win)
3973     lvalue_error (use);
3974
3975   return win;
3976 }
3977 \f
3978 /* Mark EXP saying that we need to be able to take the
3979    address of it; it should not be allocated in a register.
3980    Returns true if successful.  */
3981
3982 bool
3983 c_mark_addressable (tree exp)
3984 {
3985   tree x = exp;
3986
3987   while (1)
3988     switch (TREE_CODE (x))
3989       {
3990       case COMPONENT_REF:
3991         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3992           {
3993             error
3994               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3995             return false;
3996           }
3997
3998         /* ... fall through ...  */
3999
4000       case ADDR_EXPR:
4001       case ARRAY_REF:
4002       case REALPART_EXPR:
4003       case IMAGPART_EXPR:
4004         x = TREE_OPERAND (x, 0);
4005         break;
4006
4007       case COMPOUND_LITERAL_EXPR:
4008       case CONSTRUCTOR:
4009         TREE_ADDRESSABLE (x) = 1;
4010         return true;
4011
4012       case VAR_DECL:
4013       case CONST_DECL:
4014       case PARM_DECL:
4015       case RESULT_DECL:
4016         if (C_DECL_REGISTER (x)
4017             && DECL_NONLOCAL (x))
4018           {
4019             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
4020               {
4021                 error
4022                   ("global register variable %qD used in nested function", x);
4023                 return false;
4024               }
4025             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
4026           }
4027         else if (C_DECL_REGISTER (x))
4028           {
4029             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
4030               error ("address of global register variable %qD requested", x);
4031             else
4032               error ("address of register variable %qD requested", x);
4033             return false;
4034           }
4035
4036         /* drops in */
4037       case FUNCTION_DECL:
4038         TREE_ADDRESSABLE (x) = 1;
4039         /* drops out */
4040       default:
4041         return true;
4042     }
4043 }
4044 \f
4045 /* Convert EXPR to TYPE, warning about conversion problems with
4046    constants.  SEMANTIC_TYPE is the type this conversion would use
4047    without excess precision. If SEMANTIC_TYPE is NULL, this function
4048    is equivalent to convert_and_check. This function is a wrapper that
4049    handles conversions that may be different than
4050    the usual ones because of excess precision.  */
4051
4052 static tree
4053 ep_convert_and_check (tree type, tree expr, tree semantic_type)
4054 {
4055   if (TREE_TYPE (expr) == type)
4056     return expr;
4057
4058   if (!semantic_type)
4059     return convert_and_check (type, expr);
4060
4061   if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
4062       && TREE_TYPE (expr) != semantic_type)
4063     {
4064       /* For integers, we need to check the real conversion, not
4065          the conversion to the excess precision type.  */
4066       expr = convert_and_check (semantic_type, expr);
4067     }
4068   /* Result type is the excess precision type, which should be
4069      large enough, so do not check.  */
4070   return convert (type, expr);
4071 }
4072
4073 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
4074    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
4075    if folded to an integer constant then the unselected half may
4076    contain arbitrary operations not normally permitted in constant
4077    expressions.  Set the location of the expression to LOC.  */
4078
4079 tree
4080 build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
4081                         tree op1, tree op1_original_type, tree op2,
4082                         tree op2_original_type)
4083 {
4084   tree type1;
4085   tree type2;
4086   enum tree_code code1;
4087   enum tree_code code2;
4088   tree result_type = NULL;
4089   tree semantic_result_type = NULL;
4090   tree orig_op1 = op1, orig_op2 = op2;
4091   bool int_const, op1_int_operands, op2_int_operands, int_operands;
4092   bool ifexp_int_operands;
4093   tree ret;
4094
4095   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
4096   if (op1_int_operands)
4097     op1 = remove_c_maybe_const_expr (op1);
4098   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
4099   if (op2_int_operands)
4100     op2 = remove_c_maybe_const_expr (op2);
4101   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
4102   if (ifexp_int_operands)
4103     ifexp = remove_c_maybe_const_expr (ifexp);
4104
4105   /* Promote both alternatives.  */
4106
4107   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
4108     op1 = default_conversion (op1);
4109   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
4110     op2 = default_conversion (op2);
4111
4112   if (TREE_CODE (ifexp) == ERROR_MARK
4113       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
4114       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
4115     return error_mark_node;
4116
4117   type1 = TREE_TYPE (op1);
4118   code1 = TREE_CODE (type1);
4119   type2 = TREE_TYPE (op2);
4120   code2 = TREE_CODE (type2);
4121
4122   /* C90 does not permit non-lvalue arrays in conditional expressions.
4123      In C99 they will be pointers by now.  */
4124   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
4125     {
4126       error_at (colon_loc, "non-lvalue array in conditional expression");
4127       return error_mark_node;
4128     }
4129
4130   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
4131        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
4132       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
4133           || code1 == COMPLEX_TYPE)
4134       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
4135           || code2 == COMPLEX_TYPE))
4136     {
4137       semantic_result_type = c_common_type (type1, type2);
4138       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
4139         {
4140           op1 = TREE_OPERAND (op1, 0);
4141           type1 = TREE_TYPE (op1);
4142           gcc_assert (TREE_CODE (type1) == code1);
4143         }
4144       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
4145         {
4146           op2 = TREE_OPERAND (op2, 0);
4147           type2 = TREE_TYPE (op2);
4148           gcc_assert (TREE_CODE (type2) == code2);
4149         }
4150     }
4151
4152   if (warn_cxx_compat)
4153     {
4154       tree t1 = op1_original_type ? op1_original_type : TREE_TYPE (orig_op1);
4155       tree t2 = op2_original_type ? op2_original_type : TREE_TYPE (orig_op2);
4156
4157       if (TREE_CODE (t1) == ENUMERAL_TYPE
4158           && TREE_CODE (t2) == ENUMERAL_TYPE
4159           && TYPE_MAIN_VARIANT (t1) != TYPE_MAIN_VARIANT (t2))
4160         warning_at (colon_loc, OPT_Wc___compat,
4161                     ("different enum types in conditional is "
4162                      "invalid in C++: %qT vs %qT"),
4163                     t1, t2);
4164     }
4165
4166   /* Quickly detect the usual case where op1 and op2 have the same type
4167      after promotion.  */
4168   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
4169     {
4170       if (type1 == type2)
4171         result_type = type1;
4172       else
4173         result_type = TYPE_MAIN_VARIANT (type1);
4174     }
4175   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
4176             || code1 == COMPLEX_TYPE)
4177            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
4178                || code2 == COMPLEX_TYPE))
4179     {
4180       result_type = c_common_type (type1, type2);
4181       do_warn_double_promotion (result_type, type1, type2,
4182                                 "implicit conversion from %qT to %qT to "
4183                                 "match other result of conditional",
4184                                 colon_loc);
4185
4186       /* If -Wsign-compare, warn here if type1 and type2 have
4187          different signedness.  We'll promote the signed to unsigned
4188          and later code won't know it used to be different.
4189          Do this check on the original types, so that explicit casts
4190          will be considered, but default promotions won't.  */
4191       if (c_inhibit_evaluation_warnings == 0)
4192         {
4193           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
4194           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
4195
4196           if (unsigned_op1 ^ unsigned_op2)
4197             {
4198               bool ovf;
4199
4200               /* Do not warn if the result type is signed, since the
4201                  signed type will only be chosen if it can represent
4202                  all the values of the unsigned type.  */
4203               if (!TYPE_UNSIGNED (result_type))
4204                 /* OK */;
4205               else
4206                 {
4207                   bool op1_maybe_const = true;
4208                   bool op2_maybe_const = true;
4209
4210                   /* Do not warn if the signed quantity is an
4211                      unsuffixed integer literal (or some static
4212                      constant expression involving such literals) and
4213                      it is non-negative.  This warning requires the
4214                      operands to be folded for best results, so do
4215                      that folding in this case even without
4216                      warn_sign_compare to avoid warning options
4217                      possibly affecting code generation.  */
4218                   c_inhibit_evaluation_warnings
4219                     += (ifexp == truthvalue_false_node);
4220                   op1 = c_fully_fold (op1, require_constant_value,
4221                                       &op1_maybe_const);
4222                   c_inhibit_evaluation_warnings
4223                     -= (ifexp == truthvalue_false_node);
4224
4225                   c_inhibit_evaluation_warnings
4226                     += (ifexp == truthvalue_true_node);
4227                   op2 = c_fully_fold (op2, require_constant_value,
4228                                       &op2_maybe_const);
4229                   c_inhibit_evaluation_warnings
4230                     -= (ifexp == truthvalue_true_node);
4231
4232                   if (warn_sign_compare)
4233                     {
4234                       if ((unsigned_op2
4235                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
4236                           || (unsigned_op1
4237                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
4238                         /* OK */;
4239                       else
4240                         warning_at (colon_loc, OPT_Wsign_compare,
4241                                     ("signed and unsigned type in "
4242                                      "conditional expression"));
4243                     }
4244                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
4245                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
4246                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
4247                     op2 = c_wrap_maybe_const (op2, !op2_maybe_const);
4248                 }
4249             }
4250         }
4251     }
4252   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
4253     {
4254       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
4255         pedwarn (colon_loc, OPT_pedantic,
4256                  "ISO C forbids conditional expr with only one void side");
4257       result_type = void_type_node;
4258     }
4259   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
4260     {
4261       addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
4262       addr_space_t as2 = TYPE_ADDR_SPACE (TREE_TYPE (type2));
4263       addr_space_t as_common;
4264
4265       if (comp_target_types (colon_loc, type1, type2))
4266         result_type = common_pointer_type (type1, type2);
4267       else if (null_pointer_constant_p (orig_op1))
4268         result_type = type2;
4269       else if (null_pointer_constant_p (orig_op2))
4270         result_type = type1;
4271       else if (!addr_space_superset (as1, as2, &as_common))
4272         {
4273           error_at (colon_loc, "pointers to disjoint address spaces "
4274                     "used in conditional expression");
4275           return error_mark_node;
4276         }
4277       else if (VOID_TYPE_P (TREE_TYPE (type1)))
4278         {
4279           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
4280             pedwarn (colon_loc, OPT_pedantic,
4281                      "ISO C forbids conditional expr between "
4282                      "%<void *%> and function pointer");
4283           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
4284                                                           TREE_TYPE (type2)));
4285         }
4286       else if (VOID_TYPE_P (TREE_TYPE (type2)))
4287         {
4288           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
4289             pedwarn (colon_loc, OPT_pedantic,
4290                      "ISO C forbids conditional expr between "
4291                      "%<void *%> and function pointer");
4292           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
4293                                                           TREE_TYPE (type1)));
4294         }
4295       /* Objective-C pointer comparisons are a bit more lenient.  */
4296       else if (objc_have_common_type (type1, type2, -3, NULL_TREE))
4297         result_type = objc_common_type (type1, type2);
4298       else
4299         {
4300           int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
4301
4302           pedwarn (colon_loc, 0,
4303                    "pointer type mismatch in conditional expression");
4304           result_type = build_pointer_type
4305                           (build_qualified_type (void_type_node, qual));
4306         }
4307     }
4308   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
4309     {
4310       if (!null_pointer_constant_p (orig_op2))
4311         pedwarn (colon_loc, 0,
4312                  "pointer/integer type mismatch in conditional expression");
4313       else
4314         {
4315           op2 = null_pointer_node;
4316         }
4317       result_type = type1;
4318     }
4319   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
4320     {
4321       if (!null_pointer_constant_p (orig_op1))
4322         pedwarn (colon_loc, 0,
4323                  "pointer/integer type mismatch in conditional expression");
4324       else
4325         {
4326           op1 = null_pointer_node;
4327         }
4328       result_type = type2;
4329     }
4330
4331   if (!result_type)
4332     {
4333       if (flag_cond_mismatch)
4334         result_type = void_type_node;
4335       else
4336         {
4337           error_at (colon_loc, "type mismatch in conditional expression");
4338           return error_mark_node;
4339         }
4340     }
4341
4342   /* Merge const and volatile flags of the incoming types.  */
4343   result_type
4344     = build_type_variant (result_type,
4345                           TYPE_READONLY (type1) || TYPE_READONLY (type2),
4346                           TYPE_VOLATILE (type1) || TYPE_VOLATILE (type2));
4347
4348   op1 = ep_convert_and_check (result_type, op1, semantic_result_type);
4349   op2 = ep_convert_and_check (result_type, op2, semantic_result_type);
4350
4351   if (ifexp_bcp && ifexp == truthvalue_true_node)
4352     {
4353       op2_int_operands = true;
4354       op1 = c_fully_fold (op1, require_constant_value, NULL);
4355     }
4356   if (ifexp_bcp && ifexp == truthvalue_false_node)
4357     {
4358       op1_int_operands = true;
4359       op2 = c_fully_fold (op2, require_constant_value, NULL);
4360     }
4361   int_const = int_operands = (ifexp_int_operands
4362                               && op1_int_operands
4363                               && op2_int_operands);
4364   if (int_operands)
4365     {
4366       int_const = ((ifexp == truthvalue_true_node
4367                     && TREE_CODE (orig_op1) == INTEGER_CST
4368                     && !TREE_OVERFLOW (orig_op1))
4369                    || (ifexp == truthvalue_false_node
4370                        && TREE_CODE (orig_op2) == INTEGER_CST
4371                        && !TREE_OVERFLOW (orig_op2)));
4372     }
4373   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
4374     ret = fold_build3_loc (colon_loc, COND_EXPR, result_type, ifexp, op1, op2);
4375   else
4376     {
4377       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
4378       if (int_operands)
4379         ret = note_integer_operands (ret);
4380     }
4381   if (semantic_result_type)
4382     ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
4383
4384   protected_set_expr_location (ret, colon_loc);
4385   return ret;
4386 }
4387 \f
4388 /* Return a compound expression that performs two expressions and
4389    returns the value of the second of them.
4390
4391    LOC is the location of the COMPOUND_EXPR.  */
4392
4393 tree
4394 build_compound_expr (location_t loc, tree expr1, tree expr2)
4395 {
4396   bool expr1_int_operands, expr2_int_operands;
4397   tree eptype = NULL_TREE;
4398   tree ret;
4399
4400   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4401   if (expr1_int_operands)
4402     expr1 = remove_c_maybe_const_expr (expr1);
4403   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4404   if (expr2_int_operands)
4405     expr2 = remove_c_maybe_const_expr (expr2);
4406
4407   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4408     expr1 = TREE_OPERAND (expr1, 0);
4409   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4410     {
4411       eptype = TREE_TYPE (expr2);
4412       expr2 = TREE_OPERAND (expr2, 0);
4413     }
4414
4415   if (!TREE_SIDE_EFFECTS (expr1))
4416     {
4417       /* The left-hand operand of a comma expression is like an expression
4418          statement: with -Wunused, we should warn if it doesn't have
4419          any side-effects, unless it was explicitly cast to (void).  */
4420       if (warn_unused_value)
4421         {
4422           if (VOID_TYPE_P (TREE_TYPE (expr1))
4423               && CONVERT_EXPR_P (expr1))
4424             ; /* (void) a, b */
4425           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4426                    && TREE_CODE (expr1) == COMPOUND_EXPR
4427                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4428             ; /* (void) a, (void) b, c */
4429           else
4430             warning_at (loc, OPT_Wunused_value,
4431                         "left-hand operand of comma expression has no effect");
4432         }
4433     }
4434
4435   /* With -Wunused, we should also warn if the left-hand operand does have
4436      side-effects, but computes a value which is not used.  For example, in
4437      `foo() + bar(), baz()' the result of the `+' operator is not used,
4438      so we should issue a warning.  */
4439   else if (warn_unused_value)
4440     warn_if_unused_value (expr1, loc);
4441
4442   if (expr2 == error_mark_node)
4443     return error_mark_node;
4444
4445   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4446
4447   if (flag_isoc99
4448       && expr1_int_operands
4449       && expr2_int_operands)
4450     ret = note_integer_operands (ret);
4451
4452   if (eptype)
4453     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4454
4455   protected_set_expr_location (ret, loc);
4456   return ret;
4457 }
4458
4459 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4460    which we are casting.  OTYPE is the type of the expression being
4461    cast.  Both TYPE and OTYPE are pointer types.  LOC is the location
4462    of the cast.  -Wcast-qual appeared on the command line.  Named
4463    address space qualifiers are not handled here, because they result
4464    in different warnings.  */
4465
4466 static void
4467 handle_warn_cast_qual (location_t loc, tree type, tree otype)
4468 {
4469   tree in_type = type;
4470   tree in_otype = otype;
4471   int added = 0;
4472   int discarded = 0;
4473   bool is_const;
4474
4475   /* Check that the qualifiers on IN_TYPE are a superset of the
4476      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4477      nodes is uninteresting and we stop as soon as we hit a
4478      non-POINTER_TYPE node on either type.  */
4479   do
4480     {
4481       in_otype = TREE_TYPE (in_otype);
4482       in_type = TREE_TYPE (in_type);
4483
4484       /* GNU C allows cv-qualified function types.  'const' means the
4485          function is very pure, 'volatile' means it can't return.  We
4486          need to warn when such qualifiers are added, not when they're
4487          taken away.  */
4488       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4489           && TREE_CODE (in_type) == FUNCTION_TYPE)
4490         added |= (TYPE_QUALS_NO_ADDR_SPACE (in_type)
4491                   & ~TYPE_QUALS_NO_ADDR_SPACE (in_otype));
4492       else
4493         discarded |= (TYPE_QUALS_NO_ADDR_SPACE (in_otype)
4494                       & ~TYPE_QUALS_NO_ADDR_SPACE (in_type));
4495     }
4496   while (TREE_CODE (in_type) == POINTER_TYPE
4497          && TREE_CODE (in_otype) == POINTER_TYPE);
4498
4499   if (added)
4500     warning_at (loc, OPT_Wcast_qual,
4501                 "cast adds %q#v qualifier to function type", added);
4502
4503   if (discarded)
4504     /* There are qualifiers present in IN_OTYPE that are not present
4505        in IN_TYPE.  */
4506     warning_at (loc, OPT_Wcast_qual,
4507                 "cast discards %q#v qualifier from pointer target type",
4508                 discarded);
4509
4510   if (added || discarded)
4511     return;
4512
4513   /* A cast from **T to const **T is unsafe, because it can cause a
4514      const value to be changed with no additional warning.  We only
4515      issue this warning if T is the same on both sides, and we only
4516      issue the warning if there are the same number of pointers on
4517      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4518      cast is unsafe when a qualifier is added at one level and const
4519      is not present at all outer levels.
4520
4521      To issue this warning, we check at each level whether the cast
4522      adds new qualifiers not already seen.  We don't need to special
4523      case function types, as they won't have the same
4524      TYPE_MAIN_VARIANT.  */
4525
4526   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4527     return;
4528   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4529     return;
4530
4531   in_type = type;
4532   in_otype = otype;
4533   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4534   do
4535     {
4536       in_type = TREE_TYPE (in_type);
4537       in_otype = TREE_TYPE (in_otype);
4538       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4539           && !is_const)
4540         {
4541           warning_at (loc, OPT_Wcast_qual,
4542                       "to be safe all intermediate pointers in cast from "
4543                       "%qT to %qT must be %<const%> qualified",
4544                       otype, type);
4545           break;
4546         }
4547       if (is_const)
4548         is_const = TYPE_READONLY (in_type);
4549     }
4550   while (TREE_CODE (in_type) == POINTER_TYPE);
4551 }
4552
4553 /* Build an expression representing a cast to type TYPE of expression EXPR.
4554    LOC is the location of the cast-- typically the open paren of the cast.  */
4555
4556 tree
4557 build_c_cast (location_t loc, tree type, tree expr)
4558 {
4559   tree value;
4560
4561   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4562     expr = TREE_OPERAND (expr, 0);
4563
4564   value = expr;
4565
4566   if (type == error_mark_node || expr == error_mark_node)
4567     return error_mark_node;
4568
4569   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4570      only in <protocol> qualifications.  But when constructing cast expressions,
4571      the protocols do matter and must be kept around.  */
4572   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4573     return build1 (NOP_EXPR, type, expr);
4574
4575   type = TYPE_MAIN_VARIANT (type);
4576
4577   if (TREE_CODE (type) == ARRAY_TYPE)
4578     {
4579       error_at (loc, "cast specifies array type");
4580       return error_mark_node;
4581     }
4582
4583   if (TREE_CODE (type) == FUNCTION_TYPE)
4584     {
4585       error_at (loc, "cast specifies function type");
4586       return error_mark_node;
4587     }
4588
4589   if (!VOID_TYPE_P (type))
4590     {
4591       value = require_complete_type (value);
4592       if (value == error_mark_node)
4593         return error_mark_node;
4594     }
4595
4596   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4597     {
4598       if (TREE_CODE (type) == RECORD_TYPE
4599           || TREE_CODE (type) == UNION_TYPE)
4600         pedwarn (loc, OPT_pedantic,
4601                  "ISO C forbids casting nonscalar to the same type");
4602     }
4603   else if (TREE_CODE (type) == UNION_TYPE)
4604     {
4605       tree field;
4606
4607       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
4608         if (TREE_TYPE (field) != error_mark_node
4609             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4610                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4611           break;
4612
4613       if (field)
4614         {
4615           tree t;
4616           bool maybe_const = true;
4617
4618           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4619           t = c_fully_fold (value, false, &maybe_const);
4620           t = build_constructor_single (type, field, t);
4621           if (!maybe_const)
4622             t = c_wrap_maybe_const (t, true);
4623           t = digest_init (loc, type, t,
4624                            NULL_TREE, false, true, 0);
4625           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4626           return t;
4627         }
4628       error_at (loc, "cast to union type from type not present in union");
4629       return error_mark_node;
4630     }
4631   else
4632     {
4633       tree otype, ovalue;
4634
4635       if (type == void_type_node)
4636         {
4637           tree t = build1 (CONVERT_EXPR, type, value);
4638           SET_EXPR_LOCATION (t, loc);
4639           return t;
4640         }
4641
4642       otype = TREE_TYPE (value);
4643
4644       /* Optionally warn about potentially worrisome casts.  */
4645       if (warn_cast_qual
4646           && TREE_CODE (type) == POINTER_TYPE
4647           && TREE_CODE (otype) == POINTER_TYPE)
4648         handle_warn_cast_qual (loc, type, otype);
4649
4650       /* Warn about conversions between pointers to disjoint
4651          address spaces.  */
4652       if (TREE_CODE (type) == POINTER_TYPE
4653           && TREE_CODE (otype) == POINTER_TYPE
4654           && !null_pointer_constant_p (value))
4655         {
4656           addr_space_t as_to = TYPE_ADDR_SPACE (TREE_TYPE (type));
4657           addr_space_t as_from = TYPE_ADDR_SPACE (TREE_TYPE (otype));
4658           addr_space_t as_common;
4659
4660           if (!addr_space_superset (as_to, as_from, &as_common))
4661             {
4662               if (ADDR_SPACE_GENERIC_P (as_from))
4663                 warning_at (loc, 0, "cast to %s address space pointer "
4664                             "from disjoint generic address space pointer",
4665                             c_addr_space_name (as_to));
4666
4667               else if (ADDR_SPACE_GENERIC_P (as_to))
4668                 warning_at (loc, 0, "cast to generic address space pointer "
4669                             "from disjoint %s address space pointer",
4670                             c_addr_space_name (as_from));
4671
4672               else
4673                 warning_at (loc, 0, "cast to %s address space pointer "
4674                             "from disjoint %s address space pointer",
4675                             c_addr_space_name (as_to),
4676                             c_addr_space_name (as_from));
4677             }
4678         }
4679
4680       /* Warn about possible alignment problems.  */
4681       if (STRICT_ALIGNMENT
4682           && TREE_CODE (type) == POINTER_TYPE
4683           && TREE_CODE (otype) == POINTER_TYPE
4684           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4685           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4686           /* Don't warn about opaque types, where the actual alignment
4687              restriction is unknown.  */
4688           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4689                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4690                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4691           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4692         warning_at (loc, OPT_Wcast_align,
4693                     "cast increases required alignment of target type");
4694
4695       if (TREE_CODE (type) == INTEGER_TYPE
4696           && TREE_CODE (otype) == POINTER_TYPE
4697           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4698       /* Unlike conversion of integers to pointers, where the
4699          warning is disabled for converting constants because
4700          of cases such as SIG_*, warn about converting constant
4701          pointers to integers. In some cases it may cause unwanted
4702          sign extension, and a warning is appropriate.  */
4703         warning_at (loc, OPT_Wpointer_to_int_cast,
4704                     "cast from pointer to integer of different size");
4705
4706       if (TREE_CODE (value) == CALL_EXPR
4707           && TREE_CODE (type) != TREE_CODE (otype))
4708         warning_at (loc, OPT_Wbad_function_cast,
4709                     "cast from function call of type %qT "
4710                     "to non-matching type %qT", otype, type);
4711
4712       if (TREE_CODE (type) == POINTER_TYPE
4713           && TREE_CODE (otype) == INTEGER_TYPE
4714           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4715           /* Don't warn about converting any constant.  */
4716           && !TREE_CONSTANT (value))
4717         warning_at (loc,
4718                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4719                     "of different size");
4720
4721       if (warn_strict_aliasing <= 2)
4722         strict_aliasing_warning (otype, type, expr);
4723
4724       /* If pedantic, warn for conversions between function and object
4725          pointer types, except for converting a null pointer constant
4726          to function pointer type.  */
4727       if (pedantic
4728           && TREE_CODE (type) == POINTER_TYPE
4729           && TREE_CODE (otype) == POINTER_TYPE
4730           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4731           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4732         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4733                  "conversion of function pointer to object pointer type");
4734
4735       if (pedantic
4736           && TREE_CODE (type) == POINTER_TYPE
4737           && TREE_CODE (otype) == POINTER_TYPE
4738           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4739           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4740           && !null_pointer_constant_p (value))
4741         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4742                  "conversion of object pointer to function pointer type");
4743
4744       ovalue = value;
4745       value = convert (type, value);
4746
4747       /* Ignore any integer overflow caused by the cast.  */
4748       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4749         {
4750           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4751             {
4752               if (!TREE_OVERFLOW (value))
4753                 {
4754                   /* Avoid clobbering a shared constant.  */
4755                   value = copy_node (value);
4756                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4757                 }
4758             }
4759           else if (TREE_OVERFLOW (value))
4760             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4761             value = build_int_cst_wide (TREE_TYPE (value),
4762                                         TREE_INT_CST_LOW (value),
4763                                         TREE_INT_CST_HIGH (value));
4764         }
4765     }
4766
4767   /* Don't let a cast be an lvalue.  */
4768   if (value == expr)
4769     value = non_lvalue_loc (loc, value);
4770
4771   /* Don't allow the results of casting to floating-point or complex
4772      types be confused with actual constants, or casts involving
4773      integer and pointer types other than direct integer-to-integer
4774      and integer-to-pointer be confused with integer constant
4775      expressions and null pointer constants.  */
4776   if (TREE_CODE (value) == REAL_CST
4777       || TREE_CODE (value) == COMPLEX_CST
4778       || (TREE_CODE (value) == INTEGER_CST
4779           && !((TREE_CODE (expr) == INTEGER_CST
4780                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4781                || TREE_CODE (expr) == REAL_CST
4782                || TREE_CODE (expr) == COMPLEX_CST)))
4783       value = build1 (NOP_EXPR, type, value);
4784
4785   if (CAN_HAVE_LOCATION_P (value))
4786     SET_EXPR_LOCATION (value, loc);
4787   return value;
4788 }
4789
4790 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4791    location of the open paren of the cast, or the position of the cast
4792    expr.  */
4793 tree
4794 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4795 {
4796   tree type;
4797   tree type_expr = NULL_TREE;
4798   bool type_expr_const = true;
4799   tree ret;
4800   int saved_wsp = warn_strict_prototypes;
4801
4802   /* This avoids warnings about unprototyped casts on
4803      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4804   if (TREE_CODE (expr) == INTEGER_CST)
4805     warn_strict_prototypes = 0;
4806   type = groktypename (type_name, &type_expr, &type_expr_const);
4807   warn_strict_prototypes = saved_wsp;
4808
4809   ret = build_c_cast (loc, type, expr);
4810   if (type_expr)
4811     {
4812       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4813       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4814       SET_EXPR_LOCATION (ret, loc);
4815     }
4816
4817   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4818     SET_EXPR_LOCATION (ret, loc);
4819
4820   /* C++ does not permits types to be defined in a cast, but it
4821      allows references to incomplete types.  */
4822   if (warn_cxx_compat && type_name->specs->typespec_kind == ctsk_tagdef)
4823     warning_at (loc, OPT_Wc___compat,
4824                 "defining a type in a cast is invalid in C++");
4825
4826   return ret;
4827 }
4828 \f
4829 /* Build an assignment expression of lvalue LHS from value RHS.
4830    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4831    may differ from TREE_TYPE (LHS) for an enum bitfield.
4832    MODIFYCODE is the code for a binary operator that we use
4833    to combine the old value of LHS with RHS to get the new value.
4834    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4835    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4836    which may differ from TREE_TYPE (RHS) for an enum value.
4837
4838    LOCATION is the location of the MODIFYCODE operator.
4839    RHS_LOC is the location of the RHS.  */
4840
4841 tree
4842 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4843                    enum tree_code modifycode,
4844                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4845 {
4846   tree result;
4847   tree newrhs;
4848   tree rhs_semantic_type = NULL_TREE;
4849   tree lhstype = TREE_TYPE (lhs);
4850   tree olhstype = lhstype;
4851   bool npc;
4852
4853   /* Types that aren't fully specified cannot be used in assignments.  */
4854   lhs = require_complete_type (lhs);
4855
4856   /* Avoid duplicate error messages from operands that had errors.  */
4857   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4858     return error_mark_node;
4859
4860   /* For ObjC properties, defer this check.  */
4861   if (!objc_is_property_ref (lhs) && !lvalue_or_else (lhs, lv_assign))
4862     return error_mark_node;
4863
4864   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4865     {
4866       rhs_semantic_type = TREE_TYPE (rhs);
4867       rhs = TREE_OPERAND (rhs, 0);
4868     }
4869
4870   newrhs = rhs;
4871
4872   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4873     {
4874       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4875                                       lhs_origtype, modifycode, rhs_loc, rhs,
4876                                       rhs_origtype);
4877       if (inner == error_mark_node)
4878         return error_mark_node;
4879       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4880                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4881       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4882       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4883       protected_set_expr_location (result, location);
4884       return result;
4885     }
4886
4887   /* If a binary op has been requested, combine the old LHS value with the RHS
4888      producing the value we should actually store into the LHS.  */
4889
4890   if (modifycode != NOP_EXPR)
4891     {
4892       lhs = c_fully_fold (lhs, false, NULL);
4893       lhs = stabilize_reference (lhs);
4894       newrhs = build_binary_op (location,
4895                                 modifycode, lhs, rhs, 1);
4896
4897       /* The original type of the right hand side is no longer
4898          meaningful.  */
4899       rhs_origtype = NULL_TREE;
4900     }
4901
4902   if (c_dialect_objc ())
4903     {
4904       /* Check if we are modifying an Objective-C property reference;
4905          if so, we need to generate setter calls.  */
4906       result = objc_maybe_build_modify_expr (lhs, newrhs);
4907       if (result)
4908         return result;
4909
4910       /* Else, do the check that we postponed for Objective-C.  */
4911       if (!lvalue_or_else (lhs, lv_assign))
4912         return error_mark_node;
4913     }
4914
4915   /* Give an error for storing in something that is 'const'.  */
4916
4917   if (TYPE_READONLY (lhstype)
4918       || ((TREE_CODE (lhstype) == RECORD_TYPE
4919            || TREE_CODE (lhstype) == UNION_TYPE)
4920           && C_TYPE_FIELDS_READONLY (lhstype)))
4921     {
4922       readonly_error (lhs, lv_assign);
4923       return error_mark_node;
4924     }
4925   else if (TREE_READONLY (lhs))
4926     readonly_warning (lhs, lv_assign);
4927
4928   /* If storing into a structure or union member,
4929      it has probably been given type `int'.
4930      Compute the type that would go with
4931      the actual amount of storage the member occupies.  */
4932
4933   if (TREE_CODE (lhs) == COMPONENT_REF
4934       && (TREE_CODE (lhstype) == INTEGER_TYPE
4935           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4936           || TREE_CODE (lhstype) == REAL_TYPE
4937           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4938     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4939
4940   /* If storing in a field that is in actuality a short or narrower than one,
4941      we must store in the field in its actual type.  */
4942
4943   if (lhstype != TREE_TYPE (lhs))
4944     {
4945       lhs = copy_node (lhs);
4946       TREE_TYPE (lhs) = lhstype;
4947     }
4948
4949   /* Issue -Wc++-compat warnings about an assignment to an enum type
4950      when LHS does not have its original type.  This happens for,
4951      e.g., an enum bitfield in a struct.  */
4952   if (warn_cxx_compat
4953       && lhs_origtype != NULL_TREE
4954       && lhs_origtype != lhstype
4955       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4956     {
4957       tree checktype = (rhs_origtype != NULL_TREE
4958                         ? rhs_origtype
4959                         : TREE_TYPE (rhs));
4960       if (checktype != error_mark_node
4961           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4962         warning_at (location, OPT_Wc___compat,
4963                     "enum conversion in assignment is invalid in C++");
4964     }
4965
4966   /* Convert new value to destination type.  Fold it first, then
4967      restore any excess precision information, for the sake of
4968      conversion warnings.  */
4969
4970   npc = null_pointer_constant_p (newrhs);
4971   newrhs = c_fully_fold (newrhs, false, NULL);
4972   if (rhs_semantic_type)
4973     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4974   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4975                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4976   if (TREE_CODE (newrhs) == ERROR_MARK)
4977     return error_mark_node;
4978
4979   /* Emit ObjC write barrier, if necessary.  */
4980   if (c_dialect_objc () && flag_objc_gc)
4981     {
4982       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4983       if (result)
4984         {
4985           protected_set_expr_location (result, location);
4986           return result;
4987         }
4988     }
4989
4990   /* Scan operands.  */
4991
4992   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4993   TREE_SIDE_EFFECTS (result) = 1;
4994   protected_set_expr_location (result, location);
4995
4996   /* If we got the LHS in a different type for storing in,
4997      convert the result back to the nominal type of LHS
4998      so that the value we return always has the same type
4999      as the LHS argument.  */
5000
5001   if (olhstype == TREE_TYPE (result))
5002     return result;
5003
5004   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
5005                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
5006   protected_set_expr_location (result, location);
5007   return result;
5008 }
5009 \f
5010 /* Return whether STRUCT_TYPE has an anonymous field with type TYPE.
5011    This is used to implement -fplan9-extensions.  */
5012
5013 static bool
5014 find_anonymous_field_with_type (tree struct_type, tree type)
5015 {
5016   tree field;
5017   bool found;
5018
5019   gcc_assert (TREE_CODE (struct_type) == RECORD_TYPE
5020               || TREE_CODE (struct_type) == UNION_TYPE);
5021   found = false;
5022   for (field = TYPE_FIELDS (struct_type);
5023        field != NULL_TREE;
5024        field = TREE_CHAIN (field))
5025     {
5026       if (DECL_NAME (field) == NULL
5027           && comptypes (type, TYPE_MAIN_VARIANT (TREE_TYPE (field))))
5028         {
5029           if (found)
5030             return false;
5031           found = true;
5032         }
5033       else if (DECL_NAME (field) == NULL
5034                && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
5035                    || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5036                && find_anonymous_field_with_type (TREE_TYPE (field), type))
5037         {
5038           if (found)
5039             return false;
5040           found = true;
5041         }
5042     }
5043   return found;
5044 }
5045
5046 /* RHS is an expression whose type is pointer to struct.  If there is
5047    an anonymous field in RHS with type TYPE, then return a pointer to
5048    that field in RHS.  This is used with -fplan9-extensions.  This
5049    returns NULL if no conversion could be found.  */
5050
5051 static tree
5052 convert_to_anonymous_field (location_t location, tree type, tree rhs)
5053 {
5054   tree rhs_struct_type, lhs_main_type;
5055   tree field, found_field;
5056   bool found_sub_field;
5057   tree ret;
5058
5059   gcc_assert (POINTER_TYPE_P (TREE_TYPE (rhs)));
5060   rhs_struct_type = TREE_TYPE (TREE_TYPE (rhs));
5061   gcc_assert (TREE_CODE (rhs_struct_type) == RECORD_TYPE
5062               || TREE_CODE (rhs_struct_type) == UNION_TYPE);
5063
5064   gcc_assert (POINTER_TYPE_P (type));
5065   lhs_main_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5066
5067   found_field = NULL_TREE;
5068   found_sub_field = false;
5069   for (field = TYPE_FIELDS (rhs_struct_type);
5070        field != NULL_TREE;
5071        field = TREE_CHAIN (field))
5072     {
5073       if (DECL_NAME (field) != NULL_TREE
5074           || (TREE_CODE (TREE_TYPE (field)) != RECORD_TYPE
5075               && TREE_CODE (TREE_TYPE (field)) != UNION_TYPE))
5076         continue;
5077       if (comptypes (lhs_main_type, TYPE_MAIN_VARIANT (TREE_TYPE (field))))
5078         {
5079           if (found_field != NULL_TREE)
5080             return NULL_TREE;
5081           found_field = field;
5082         }
5083       else if (find_anonymous_field_with_type (TREE_TYPE (field),
5084                                                lhs_main_type))
5085         {
5086           if (found_field != NULL_TREE)
5087             return NULL_TREE;
5088           found_field = field;
5089           found_sub_field = true;
5090         }
5091     }
5092
5093   if (found_field == NULL_TREE)
5094     return NULL_TREE;
5095
5096   ret = fold_build3_loc (location, COMPONENT_REF, TREE_TYPE (found_field),
5097                          build_fold_indirect_ref (rhs), found_field,
5098                          NULL_TREE);
5099   ret = build_fold_addr_expr_loc (location, ret);
5100
5101   if (found_sub_field)
5102     {
5103       ret = convert_to_anonymous_field (location, type, ret);
5104       gcc_assert (ret != NULL_TREE);
5105     }
5106
5107   return ret;
5108 }
5109
5110 /* Convert value RHS to type TYPE as preparation for an assignment to
5111    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
5112    original type of RHS; this differs from TREE_TYPE (RHS) for enum
5113    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
5114    constant before any folding.
5115    The real work of conversion is done by `convert'.
5116    The purpose of this function is to generate error messages
5117    for assignments that are not allowed in C.
5118    ERRTYPE says whether it is argument passing, assignment,
5119    initialization or return.
5120
5121    LOCATION is the location of the RHS.
5122    FUNCTION is a tree for the function being called.
5123    PARMNUM is the number of the argument, for printing in error messages.  */
5124
5125 static tree
5126 convert_for_assignment (location_t location, tree type, tree rhs,
5127                         tree origtype, enum impl_conv errtype,
5128                         bool null_pointer_constant, tree fundecl,
5129                         tree function, int parmnum)
5130 {
5131   enum tree_code codel = TREE_CODE (type);
5132   tree orig_rhs = rhs;
5133   tree rhstype;
5134   enum tree_code coder;
5135   tree rname = NULL_TREE;
5136   bool objc_ok = false;
5137
5138   if (errtype == ic_argpass)
5139     {
5140       tree selector;
5141       /* Change pointer to function to the function itself for
5142          diagnostics.  */
5143       if (TREE_CODE (function) == ADDR_EXPR
5144           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
5145         function = TREE_OPERAND (function, 0);
5146
5147       /* Handle an ObjC selector specially for diagnostics.  */
5148       selector = objc_message_selector ();
5149       rname = function;
5150       if (selector && parmnum > 2)
5151         {
5152           rname = selector;
5153           parmnum -= 2;
5154         }
5155     }
5156
5157   /* This macro is used to emit diagnostics to ensure that all format
5158      strings are complete sentences, visible to gettext and checked at
5159      compile time.  */
5160 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
5161   do {                                                                   \
5162     switch (errtype)                                                     \
5163       {                                                                  \
5164       case ic_argpass:                                                   \
5165         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
5166           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
5167                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
5168                   "expected %qT but argument is of type %qT",            \
5169                   type, rhstype);                                        \
5170         break;                                                           \
5171       case ic_assign:                                                    \
5172         pedwarn (LOCATION, OPT, AS);                                     \
5173         break;                                                           \
5174       case ic_init:                                                      \
5175         pedwarn_init (LOCATION, OPT, IN);                                \
5176         break;                                                           \
5177       case ic_return:                                                    \
5178         pedwarn (LOCATION, OPT, RE);                                     \
5179         break;                                                           \
5180       default:                                                           \
5181         gcc_unreachable ();                                              \
5182       }                                                                  \
5183   } while (0)
5184
5185   /* This macro is used to emit diagnostics to ensure that all format
5186      strings are complete sentences, visible to gettext and checked at
5187      compile time.  It is the same as WARN_FOR_ASSIGNMENT but with an
5188      extra parameter to enumerate qualifiers.  */
5189
5190 #define WARN_FOR_QUALIFIERS(LOCATION, OPT, AR, AS, IN, RE, QUALS)        \
5191   do {                                                                   \
5192     switch (errtype)                                                     \
5193       {                                                                  \
5194       case ic_argpass:                                                   \
5195         if (pedwarn (LOCATION, OPT, AR, parmnum, rname, QUALS))          \
5196           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
5197                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
5198                   "expected %qT but argument is of type %qT",            \
5199                   type, rhstype);                                        \
5200         break;                                                           \
5201       case ic_assign:                                                    \
5202         pedwarn (LOCATION, OPT, AS, QUALS);                          \
5203         break;                                                           \
5204       case ic_init:                                                      \
5205         pedwarn (LOCATION, OPT, IN, QUALS);                          \
5206         break;                                                           \
5207       case ic_return:                                                    \
5208         pedwarn (LOCATION, OPT, RE, QUALS);                              \
5209         break;                                                           \
5210       default:                                                           \
5211         gcc_unreachable ();                                              \
5212       }                                                                  \
5213   } while (0)
5214
5215   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
5216     rhs = TREE_OPERAND (rhs, 0);
5217
5218   rhstype = TREE_TYPE (rhs);
5219   coder = TREE_CODE (rhstype);
5220
5221   if (coder == ERROR_MARK)
5222     return error_mark_node;
5223
5224   if (c_dialect_objc ())
5225     {
5226       int parmno;
5227
5228       switch (errtype)
5229         {
5230         case ic_return:
5231           parmno = 0;
5232           break;
5233
5234         case ic_assign:
5235           parmno = -1;
5236           break;
5237
5238         case ic_init:
5239           parmno = -2;
5240           break;
5241
5242         default:
5243           parmno = parmnum;
5244           break;
5245         }
5246
5247       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
5248     }
5249
5250   if (warn_cxx_compat)
5251     {
5252       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
5253       if (checktype != error_mark_node
5254           && TREE_CODE (type) == ENUMERAL_TYPE
5255           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
5256         {
5257           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
5258                                G_("enum conversion when passing argument "
5259                                   "%d of %qE is invalid in C++"),
5260                                G_("enum conversion in assignment is "
5261                                   "invalid in C++"),
5262                                G_("enum conversion in initialization is "
5263                                   "invalid in C++"),
5264                                G_("enum conversion in return is "
5265                                   "invalid in C++"));
5266         }
5267     }
5268
5269   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
5270     return rhs;
5271
5272   if (coder == VOID_TYPE)
5273     {
5274       /* Except for passing an argument to an unprototyped function,
5275          this is a constraint violation.  When passing an argument to
5276          an unprototyped function, it is compile-time undefined;
5277          making it a constraint in that case was rejected in
5278          DR#252.  */
5279       error_at (location, "void value not ignored as it ought to be");
5280       return error_mark_node;
5281     }
5282   rhs = require_complete_type (rhs);
5283   if (rhs == error_mark_node)
5284     return error_mark_node;
5285   /* A type converts to a reference to it.
5286      This code doesn't fully support references, it's just for the
5287      special case of va_start and va_copy.  */
5288   if (codel == REFERENCE_TYPE
5289       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
5290     {
5291       if (!lvalue_p (rhs))
5292         {
5293           error_at (location, "cannot pass rvalue to reference parameter");
5294           return error_mark_node;
5295         }
5296       if (!c_mark_addressable (rhs))
5297         return error_mark_node;
5298       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
5299       SET_EXPR_LOCATION (rhs, location);
5300
5301       /* We already know that these two types are compatible, but they
5302          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
5303          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
5304          likely to be va_list, a typedef to __builtin_va_list, which
5305          is different enough that it will cause problems later.  */
5306       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
5307         {
5308           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
5309           SET_EXPR_LOCATION (rhs, location);
5310         }
5311
5312       rhs = build1 (NOP_EXPR, type, rhs);
5313       SET_EXPR_LOCATION (rhs, location);
5314       return rhs;
5315     }
5316   /* Some types can interconvert without explicit casts.  */
5317   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
5318            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
5319     return convert (type, rhs);
5320   /* Arithmetic types all interconvert, and enum is treated like int.  */
5321   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
5322             || codel == FIXED_POINT_TYPE
5323             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
5324             || codel == BOOLEAN_TYPE)
5325            && (coder == INTEGER_TYPE || coder == REAL_TYPE
5326                || coder == FIXED_POINT_TYPE
5327                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
5328                || coder == BOOLEAN_TYPE))
5329     {
5330       tree ret;
5331       bool save = in_late_binary_op;
5332       if (codel == BOOLEAN_TYPE)
5333         in_late_binary_op = true;
5334       ret = convert_and_check (type, orig_rhs);
5335       if (codel == BOOLEAN_TYPE)
5336         in_late_binary_op = save;
5337       return ret;
5338     }
5339
5340   /* Aggregates in different TUs might need conversion.  */
5341   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
5342       && codel == coder
5343       && comptypes (type, rhstype))
5344     return convert_and_check (type, rhs);
5345
5346   /* Conversion to a transparent union or record from its member types.
5347      This applies only to function arguments.  */
5348   if (((codel == UNION_TYPE || codel == RECORD_TYPE)
5349       && TYPE_TRANSPARENT_AGGR (type))
5350       && errtype == ic_argpass)
5351     {
5352       tree memb, marginal_memb = NULL_TREE;
5353
5354       for (memb = TYPE_FIELDS (type); memb ; memb = DECL_CHAIN (memb))
5355         {
5356           tree memb_type = TREE_TYPE (memb);
5357
5358           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
5359                          TYPE_MAIN_VARIANT (rhstype)))
5360             break;
5361
5362           if (TREE_CODE (memb_type) != POINTER_TYPE)
5363             continue;
5364
5365           if (coder == POINTER_TYPE)
5366             {
5367               tree ttl = TREE_TYPE (memb_type);
5368               tree ttr = TREE_TYPE (rhstype);
5369
5370               /* Any non-function converts to a [const][volatile] void *
5371                  and vice versa; otherwise, targets must be the same.
5372                  Meanwhile, the lhs target must have all the qualifiers of
5373                  the rhs.  */
5374               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5375                   || comp_target_types (location, memb_type, rhstype))
5376                 {
5377                   /* If this type won't generate any warnings, use it.  */
5378                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
5379                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
5380                            && TREE_CODE (ttl) == FUNCTION_TYPE)
5381                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5382                              == TYPE_QUALS (ttr))
5383                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5384                              == TYPE_QUALS (ttl))))
5385                     break;
5386
5387                   /* Keep looking for a better type, but remember this one.  */
5388                   if (!marginal_memb)
5389                     marginal_memb = memb;
5390                 }
5391             }
5392
5393           /* Can convert integer zero to any pointer type.  */
5394           if (null_pointer_constant)
5395             {
5396               rhs = null_pointer_node;
5397               break;
5398             }
5399         }
5400
5401       if (memb || marginal_memb)
5402         {
5403           if (!memb)
5404             {
5405               /* We have only a marginally acceptable member type;
5406                  it needs a warning.  */
5407               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
5408               tree ttr = TREE_TYPE (rhstype);
5409
5410               /* Const and volatile mean something different for function
5411                  types, so the usual warnings are not appropriate.  */
5412               if (TREE_CODE (ttr) == FUNCTION_TYPE
5413                   && TREE_CODE (ttl) == FUNCTION_TYPE)
5414                 {
5415                   /* Because const and volatile on functions are
5416                      restrictions that say the function will not do
5417                      certain things, it is okay to use a const or volatile
5418                      function where an ordinary one is wanted, but not
5419                      vice-versa.  */
5420                   if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5421                       & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5422                     WARN_FOR_QUALIFIERS (location, 0,
5423                                          G_("passing argument %d of %qE "
5424                                             "makes %q#v qualified function "
5425                                             "pointer from unqualified"),
5426                                          G_("assignment makes %q#v qualified "
5427                                             "function pointer from "
5428                                             "unqualified"),
5429                                          G_("initialization makes %q#v qualified "
5430                                             "function pointer from "
5431                                             "unqualified"),
5432                                          G_("return makes %q#v qualified function "
5433                                             "pointer from unqualified"),
5434                                          TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr));
5435                 }
5436               else if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5437                        & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5438                 WARN_FOR_QUALIFIERS (location, 0,
5439                                      G_("passing argument %d of %qE discards "
5440                                         "%qv qualifier from pointer target type"),
5441                                      G_("assignment discards %qv qualifier "
5442                                         "from pointer target type"),
5443                                      G_("initialization discards %qv qualifier "
5444                                         "from pointer target type"),
5445                                      G_("return discards %qv qualifier from "
5446                                         "pointer target type"),
5447                                      TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
5448
5449               memb = marginal_memb;
5450             }
5451
5452           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
5453             pedwarn (location, OPT_pedantic,
5454                      "ISO C prohibits argument conversion to union type");
5455
5456           rhs = fold_convert_loc (location, TREE_TYPE (memb), rhs);
5457           return build_constructor_single (type, memb, rhs);
5458         }
5459     }
5460
5461   /* Conversions among pointers */
5462   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
5463            && (coder == codel))
5464     {
5465       tree ttl = TREE_TYPE (type);
5466       tree ttr = TREE_TYPE (rhstype);
5467       tree mvl = ttl;
5468       tree mvr = ttr;
5469       bool is_opaque_pointer;
5470       int target_cmp = 0;   /* Cache comp_target_types () result.  */
5471       addr_space_t asl;
5472       addr_space_t asr;
5473
5474       if (TREE_CODE (mvl) != ARRAY_TYPE)
5475         mvl = TYPE_MAIN_VARIANT (mvl);
5476       if (TREE_CODE (mvr) != ARRAY_TYPE)
5477         mvr = TYPE_MAIN_VARIANT (mvr);
5478       /* Opaque pointers are treated like void pointers.  */
5479       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
5480
5481       /* The Plan 9 compiler permits a pointer to a struct to be
5482          automatically converted into a pointer to an anonymous field
5483          within the struct.  */
5484       if (flag_plan9_extensions
5485           && (TREE_CODE (mvl) == RECORD_TYPE || TREE_CODE(mvl) == UNION_TYPE)
5486           && (TREE_CODE (mvr) == RECORD_TYPE || TREE_CODE(mvr) == UNION_TYPE)
5487           && mvl != mvr)
5488         {
5489           tree new_rhs = convert_to_anonymous_field (location, type, rhs);
5490           if (new_rhs != NULL_TREE)
5491             {
5492               rhs = new_rhs;
5493               rhstype = TREE_TYPE (rhs);
5494               coder = TREE_CODE (rhstype);
5495               ttr = TREE_TYPE (rhstype);
5496               mvr = TYPE_MAIN_VARIANT (ttr);
5497             }
5498         }
5499
5500       /* C++ does not allow the implicit conversion void* -> T*.  However,
5501          for the purpose of reducing the number of false positives, we
5502          tolerate the special case of
5503
5504                 int *p = NULL;
5505
5506          where NULL is typically defined in C to be '(void *) 0'.  */
5507       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
5508         warning_at (location, OPT_Wc___compat,
5509                     "request for implicit conversion "
5510                     "from %qT to %qT not permitted in C++", rhstype, type);
5511
5512       /* See if the pointers point to incompatible address spaces.  */
5513       asl = TYPE_ADDR_SPACE (ttl);
5514       asr = TYPE_ADDR_SPACE (ttr);
5515       if (!null_pointer_constant_p (rhs)
5516           && asr != asl && !targetm.addr_space.subset_p (asr, asl))
5517         {
5518           switch (errtype)
5519             {
5520             case ic_argpass:
5521               error_at (location, "passing argument %d of %qE from pointer to "
5522                         "non-enclosed address space", parmnum, rname);
5523               break;
5524             case ic_assign:
5525               error_at (location, "assignment from pointer to "
5526                         "non-enclosed address space");
5527               break;
5528             case ic_init:
5529               error_at (location, "initialization from pointer to "
5530                         "non-enclosed address space");
5531               break;
5532             case ic_return:
5533               error_at (location, "return from pointer to "
5534                         "non-enclosed address space");
5535               break;
5536             default:
5537               gcc_unreachable ();
5538             }
5539           return error_mark_node;
5540         }
5541
5542       /* Check if the right-hand side has a format attribute but the
5543          left-hand side doesn't.  */
5544       if (warn_missing_format_attribute
5545           && check_missing_format_attribute (type, rhstype))
5546         {
5547           switch (errtype)
5548           {
5549           case ic_argpass:
5550             warning_at (location, OPT_Wmissing_format_attribute,
5551                         "argument %d of %qE might be "
5552                         "a candidate for a format attribute",
5553                         parmnum, rname);
5554             break;
5555           case ic_assign:
5556             warning_at (location, OPT_Wmissing_format_attribute,
5557                         "assignment left-hand side might be "
5558                         "a candidate for a format attribute");
5559             break;
5560           case ic_init:
5561             warning_at (location, OPT_Wmissing_format_attribute,
5562                         "initialization left-hand side might be "
5563                         "a candidate for a format attribute");
5564             break;
5565           case ic_return:
5566             warning_at (location, OPT_Wmissing_format_attribute,
5567                         "return type might be "
5568                         "a candidate for a format attribute");
5569             break;
5570           default:
5571             gcc_unreachable ();
5572           }
5573         }
5574
5575       /* Any non-function converts to a [const][volatile] void *
5576          and vice versa; otherwise, targets must be the same.
5577          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5578       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5579           || (target_cmp = comp_target_types (location, type, rhstype))
5580           || is_opaque_pointer
5581           || (c_common_unsigned_type (mvl)
5582               == c_common_unsigned_type (mvr)))
5583         {
5584           if (pedantic
5585               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5586                   ||
5587                   (VOID_TYPE_P (ttr)
5588                    && !null_pointer_constant
5589                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5590             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5591                                  G_("ISO C forbids passing argument %d of "
5592                                     "%qE between function pointer "
5593                                     "and %<void *%>"),
5594                                  G_("ISO C forbids assignment between "
5595                                     "function pointer and %<void *%>"),
5596                                  G_("ISO C forbids initialization between "
5597                                     "function pointer and %<void *%>"),
5598                                  G_("ISO C forbids return between function "
5599                                     "pointer and %<void *%>"));
5600           /* Const and volatile mean something different for function types,
5601              so the usual warnings are not appropriate.  */
5602           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5603                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5604             {
5605               if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5606                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5607                 {
5608                   /* Types differing only by the presence of the 'volatile'
5609                      qualifier are acceptable if the 'volatile' has been added
5610                      in by the Objective-C EH machinery.  */
5611                   if (!objc_type_quals_match (ttl, ttr))
5612                     WARN_FOR_QUALIFIERS (location, 0,
5613                                          G_("passing argument %d of %qE discards "
5614                                             "%qv qualifier from pointer target type"),
5615                                          G_("assignment discards %qv qualifier "
5616                                             "from pointer target type"),
5617                                          G_("initialization discards %qv qualifier "
5618                                             "from pointer target type"),
5619                                          G_("return discards %qv qualifier from "
5620                                             "pointer target type"),
5621                                          TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
5622                 }
5623               /* If this is not a case of ignoring a mismatch in signedness,
5624                  no warning.  */
5625               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5626                        || target_cmp)
5627                 ;
5628               /* If there is a mismatch, do warn.  */
5629               else if (warn_pointer_sign)
5630                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5631                                      G_("pointer targets in passing argument "
5632                                         "%d of %qE differ in signedness"),
5633                                      G_("pointer targets in assignment "
5634                                         "differ in signedness"),
5635                                      G_("pointer targets in initialization "
5636                                         "differ in signedness"),
5637                                      G_("pointer targets in return differ "
5638                                         "in signedness"));
5639             }
5640           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5641                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5642             {
5643               /* Because const and volatile on functions are restrictions
5644                  that say the function will not do certain things,
5645                  it is okay to use a const or volatile function
5646                  where an ordinary one is wanted, but not vice-versa.  */
5647               if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5648                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5649                 WARN_FOR_QUALIFIERS (location, 0,
5650                                      G_("passing argument %d of %qE makes "
5651                                         "%q#v qualified function pointer "
5652                                         "from unqualified"),
5653                                      G_("assignment makes %q#v qualified function "
5654                                         "pointer from unqualified"),
5655                                      G_("initialization makes %q#v qualified "
5656                                         "function pointer from unqualified"),
5657                                      G_("return makes %q#v qualified function "
5658                                         "pointer from unqualified"),
5659                                      TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr));
5660             }
5661         }
5662       else
5663         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5664         if (!objc_ok)
5665           WARN_FOR_ASSIGNMENT (location, 0,
5666                                G_("passing argument %d of %qE from "
5667                                   "incompatible pointer type"),
5668                                G_("assignment from incompatible pointer type"),
5669                                G_("initialization from incompatible "
5670                                   "pointer type"),
5671                                G_("return from incompatible pointer type"));
5672
5673       return convert (type, rhs);
5674     }
5675   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5676     {
5677       /* ??? This should not be an error when inlining calls to
5678          unprototyped functions.  */
5679       error_at (location, "invalid use of non-lvalue array");
5680       return error_mark_node;
5681     }
5682   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5683     {
5684       /* An explicit constant 0 can convert to a pointer,
5685          or one that results from arithmetic, even including
5686          a cast to integer type.  */
5687       if (!null_pointer_constant)
5688         WARN_FOR_ASSIGNMENT (location, 0,
5689                              G_("passing argument %d of %qE makes "
5690                                 "pointer from integer without a cast"),
5691                              G_("assignment makes pointer from integer "
5692                                 "without a cast"),
5693                              G_("initialization makes pointer from "
5694                                 "integer without a cast"),
5695                              G_("return makes pointer from integer "
5696                                 "without a cast"));
5697
5698       return convert (type, rhs);
5699     }
5700   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5701     {
5702       WARN_FOR_ASSIGNMENT (location, 0,
5703                            G_("passing argument %d of %qE makes integer "
5704                               "from pointer without a cast"),
5705                            G_("assignment makes integer from pointer "
5706                               "without a cast"),
5707                            G_("initialization makes integer from pointer "
5708                               "without a cast"),
5709                            G_("return makes integer from pointer "
5710                               "without a cast"));
5711       return convert (type, rhs);
5712     }
5713   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5714     {
5715       tree ret;
5716       bool save = in_late_binary_op;
5717       in_late_binary_op = true;
5718       ret = convert (type, rhs);
5719       in_late_binary_op = save;
5720       return ret;
5721     }
5722
5723   switch (errtype)
5724     {
5725     case ic_argpass:
5726       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5727       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5728               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5729               "expected %qT but argument is of type %qT", type, rhstype);
5730       break;
5731     case ic_assign:
5732       error_at (location, "incompatible types when assigning to type %qT from "
5733                 "type %qT", type, rhstype);
5734       break;
5735     case ic_init:
5736       error_at (location,
5737                 "incompatible types when initializing type %qT using type %qT",
5738                 type, rhstype);
5739       break;
5740     case ic_return:
5741       error_at (location,
5742                 "incompatible types when returning type %qT but %qT was "
5743                 "expected", rhstype, type);
5744       break;
5745     default:
5746       gcc_unreachable ();
5747     }
5748
5749   return error_mark_node;
5750 }
5751 \f
5752 /* If VALUE is a compound expr all of whose expressions are constant, then
5753    return its value.  Otherwise, return error_mark_node.
5754
5755    This is for handling COMPOUND_EXPRs as initializer elements
5756    which is allowed with a warning when -pedantic is specified.  */
5757
5758 static tree
5759 valid_compound_expr_initializer (tree value, tree endtype)
5760 {
5761   if (TREE_CODE (value) == COMPOUND_EXPR)
5762     {
5763       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5764           == error_mark_node)
5765         return error_mark_node;
5766       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5767                                               endtype);
5768     }
5769   else if (!initializer_constant_valid_p (value, endtype))
5770     return error_mark_node;
5771   else
5772     return value;
5773 }
5774 \f
5775 /* Perform appropriate conversions on the initial value of a variable,
5776    store it in the declaration DECL,
5777    and print any error messages that are appropriate.
5778    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5779    If the init is invalid, store an ERROR_MARK.
5780
5781    INIT_LOC is the location of the initial value.  */
5782
5783 void
5784 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5785 {
5786   tree value, type;
5787   bool npc = false;
5788
5789   /* If variable's type was invalidly declared, just ignore it.  */
5790
5791   type = TREE_TYPE (decl);
5792   if (TREE_CODE (type) == ERROR_MARK)
5793     return;
5794
5795   /* Digest the specified initializer into an expression.  */
5796
5797   if (init)
5798     npc = null_pointer_constant_p (init);
5799   value = digest_init (init_loc, type, init, origtype, npc,
5800                        true, TREE_STATIC (decl));
5801
5802   /* Store the expression if valid; else report error.  */
5803
5804   if (!in_system_header
5805       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5806     warning (OPT_Wtraditional, "traditional C rejects automatic "
5807              "aggregate initialization");
5808
5809   DECL_INITIAL (decl) = value;
5810
5811   /* ANSI wants warnings about out-of-range constant initializers.  */
5812   STRIP_TYPE_NOPS (value);
5813   if (TREE_STATIC (decl))
5814     constant_expression_warning (value);
5815
5816   /* Check if we need to set array size from compound literal size.  */
5817   if (TREE_CODE (type) == ARRAY_TYPE
5818       && TYPE_DOMAIN (type) == 0
5819       && value != error_mark_node)
5820     {
5821       tree inside_init = init;
5822
5823       STRIP_TYPE_NOPS (inside_init);
5824       inside_init = fold (inside_init);
5825
5826       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5827         {
5828           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5829
5830           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5831             {
5832               /* For int foo[] = (int [3]){1}; we need to set array size
5833                  now since later on array initializer will be just the
5834                  brace enclosed list of the compound literal.  */
5835               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5836               TREE_TYPE (decl) = type;
5837               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5838               layout_type (type);
5839               layout_decl (cldecl, 0);
5840             }
5841         }
5842     }
5843 }
5844 \f
5845 /* Methods for storing and printing names for error messages.  */
5846
5847 /* Implement a spelling stack that allows components of a name to be pushed
5848    and popped.  Each element on the stack is this structure.  */
5849
5850 struct spelling
5851 {
5852   int kind;
5853   union
5854     {
5855       unsigned HOST_WIDE_INT i;
5856       const char *s;
5857     } u;
5858 };
5859
5860 #define SPELLING_STRING 1
5861 #define SPELLING_MEMBER 2
5862 #define SPELLING_BOUNDS 3
5863
5864 static struct spelling *spelling;       /* Next stack element (unused).  */
5865 static struct spelling *spelling_base;  /* Spelling stack base.  */
5866 static int spelling_size;               /* Size of the spelling stack.  */
5867
5868 /* Macros to save and restore the spelling stack around push_... functions.
5869    Alternative to SAVE_SPELLING_STACK.  */
5870
5871 #define SPELLING_DEPTH() (spelling - spelling_base)
5872 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5873
5874 /* Push an element on the spelling stack with type KIND and assign VALUE
5875    to MEMBER.  */
5876
5877 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5878 {                                                                       \
5879   int depth = SPELLING_DEPTH ();                                        \
5880                                                                         \
5881   if (depth >= spelling_size)                                           \
5882     {                                                                   \
5883       spelling_size += 10;                                              \
5884       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5885                                   spelling_size);                       \
5886       RESTORE_SPELLING_DEPTH (depth);                                   \
5887     }                                                                   \
5888                                                                         \
5889   spelling->kind = (KIND);                                              \
5890   spelling->MEMBER = (VALUE);                                           \
5891   spelling++;                                                           \
5892 }
5893
5894 /* Push STRING on the stack.  Printed literally.  */
5895
5896 static void
5897 push_string (const char *string)
5898 {
5899   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5900 }
5901
5902 /* Push a member name on the stack.  Printed as '.' STRING.  */
5903
5904 static void
5905 push_member_name (tree decl)
5906 {
5907   const char *const string
5908     = (DECL_NAME (decl)
5909        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5910        : _("<anonymous>"));
5911   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5912 }
5913
5914 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5915
5916 static void
5917 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5918 {
5919   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5920 }
5921
5922 /* Compute the maximum size in bytes of the printed spelling.  */
5923
5924 static int
5925 spelling_length (void)
5926 {
5927   int size = 0;
5928   struct spelling *p;
5929
5930   for (p = spelling_base; p < spelling; p++)
5931     {
5932       if (p->kind == SPELLING_BOUNDS)
5933         size += 25;
5934       else
5935         size += strlen (p->u.s) + 1;
5936     }
5937
5938   return size;
5939 }
5940
5941 /* Print the spelling to BUFFER and return it.  */
5942
5943 static char *
5944 print_spelling (char *buffer)
5945 {
5946   char *d = buffer;
5947   struct spelling *p;
5948
5949   for (p = spelling_base; p < spelling; p++)
5950     if (p->kind == SPELLING_BOUNDS)
5951       {
5952         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5953         d += strlen (d);
5954       }
5955     else
5956       {
5957         const char *s;
5958         if (p->kind == SPELLING_MEMBER)
5959           *d++ = '.';
5960         for (s = p->u.s; (*d = *s++); d++)
5961           ;
5962       }
5963   *d++ = '\0';
5964   return buffer;
5965 }
5966
5967 /* Issue an error message for a bad initializer component.
5968    GMSGID identifies the message.
5969    The component name is taken from the spelling stack.  */
5970
5971 void
5972 error_init (const char *gmsgid)
5973 {
5974   char *ofwhat;
5975
5976   /* The gmsgid may be a format string with %< and %>. */
5977   error (gmsgid);
5978   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5979   if (*ofwhat)
5980     error ("(near initialization for %qs)", ofwhat);
5981 }
5982
5983 /* Issue a pedantic warning for a bad initializer component.  OPT is
5984    the option OPT_* (from options.h) controlling this warning or 0 if
5985    it is unconditionally given.  GMSGID identifies the message.  The
5986    component name is taken from the spelling stack.  */
5987
5988 void
5989 pedwarn_init (location_t location, int opt, const char *gmsgid)
5990 {
5991   char *ofwhat;
5992
5993   /* The gmsgid may be a format string with %< and %>. */
5994   pedwarn (location, opt, gmsgid);
5995   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5996   if (*ofwhat)
5997     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5998 }
5999
6000 /* Issue a warning for a bad initializer component.
6001
6002    OPT is the OPT_W* value corresponding to the warning option that
6003    controls this warning.  GMSGID identifies the message.  The
6004    component name is taken from the spelling stack.  */
6005
6006 static void
6007 warning_init (int opt, const char *gmsgid)
6008 {
6009   char *ofwhat;
6010
6011   /* The gmsgid may be a format string with %< and %>. */
6012   warning (opt, gmsgid);
6013   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
6014   if (*ofwhat)
6015     warning (opt, "(near initialization for %qs)", ofwhat);
6016 }
6017 \f
6018 /* If TYPE is an array type and EXPR is a parenthesized string
6019    constant, warn if pedantic that EXPR is being used to initialize an
6020    object of type TYPE.  */
6021
6022 void
6023 maybe_warn_string_init (tree type, struct c_expr expr)
6024 {
6025   if (pedantic
6026       && TREE_CODE (type) == ARRAY_TYPE
6027       && TREE_CODE (expr.value) == STRING_CST
6028       && expr.original_code != STRING_CST)
6029     pedwarn_init (input_location, OPT_pedantic,
6030                   "array initialized from parenthesized string constant");
6031 }
6032
6033 /* Digest the parser output INIT as an initializer for type TYPE.
6034    Return a C expression of type TYPE to represent the initial value.
6035
6036    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
6037
6038    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
6039
6040    If INIT is a string constant, STRICT_STRING is true if it is
6041    unparenthesized or we should not warn here for it being parenthesized.
6042    For other types of INIT, STRICT_STRING is not used.
6043
6044    INIT_LOC is the location of the INIT.
6045
6046    REQUIRE_CONSTANT requests an error if non-constant initializers or
6047    elements are seen.  */
6048
6049 static tree
6050 digest_init (location_t init_loc, tree type, tree init, tree origtype,
6051              bool null_pointer_constant, bool strict_string,
6052              int require_constant)
6053 {
6054   enum tree_code code = TREE_CODE (type);
6055   tree inside_init = init;
6056   tree semantic_type = NULL_TREE;
6057   bool maybe_const = true;
6058
6059   if (type == error_mark_node
6060       || !init
6061       || init == error_mark_node
6062       || TREE_TYPE (init) == error_mark_node)
6063     return error_mark_node;
6064
6065   STRIP_TYPE_NOPS (inside_init);
6066
6067   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
6068     {
6069       semantic_type = TREE_TYPE (inside_init);
6070       inside_init = TREE_OPERAND (inside_init, 0);
6071     }
6072   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
6073   inside_init = decl_constant_value_for_optimization (inside_init);
6074
6075   /* Initialization of an array of chars from a string constant
6076      optionally enclosed in braces.  */
6077
6078   if (code == ARRAY_TYPE && inside_init
6079       && TREE_CODE (inside_init) == STRING_CST)
6080     {
6081       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
6082       /* Note that an array could be both an array of character type
6083          and an array of wchar_t if wchar_t is signed char or unsigned
6084          char.  */
6085       bool char_array = (typ1 == char_type_node
6086                          || typ1 == signed_char_type_node
6087                          || typ1 == unsigned_char_type_node);
6088       bool wchar_array = !!comptypes (typ1, wchar_type_node);
6089       bool char16_array = !!comptypes (typ1, char16_type_node);
6090       bool char32_array = !!comptypes (typ1, char32_type_node);
6091
6092       if (char_array || wchar_array || char16_array || char32_array)
6093         {
6094           struct c_expr expr;
6095           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
6096           expr.value = inside_init;
6097           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
6098           expr.original_type = NULL;
6099           maybe_warn_string_init (type, expr);
6100
6101           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
6102             pedwarn_init (init_loc, OPT_pedantic,
6103                           "initialization of a flexible array member");
6104
6105           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6106                          TYPE_MAIN_VARIANT (type)))
6107             return inside_init;
6108
6109           if (char_array)
6110             {
6111               if (typ2 != char_type_node)
6112                 {
6113                   error_init ("char-array initialized from wide string");
6114                   return error_mark_node;
6115                 }
6116             }
6117           else
6118             {
6119               if (typ2 == char_type_node)
6120                 {
6121                   error_init ("wide character array initialized from non-wide "
6122                               "string");
6123                   return error_mark_node;
6124                 }
6125               else if (!comptypes(typ1, typ2))
6126                 {
6127                   error_init ("wide character array initialized from "
6128                               "incompatible wide string");
6129                   return error_mark_node;
6130                 }
6131             }
6132
6133           TREE_TYPE (inside_init) = type;
6134           if (TYPE_DOMAIN (type) != 0
6135               && TYPE_SIZE (type) != 0
6136               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
6137             {
6138               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
6139
6140               /* Subtract the size of a single (possibly wide) character
6141                  because it's ok to ignore the terminating null char
6142                  that is counted in the length of the constant.  */
6143               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
6144                                         (len
6145                                          - (TYPE_PRECISION (typ1)
6146                                             / BITS_PER_UNIT))))
6147                 pedwarn_init (init_loc, 0,
6148                               ("initializer-string for array of chars "
6149                                "is too long"));
6150               else if (warn_cxx_compat
6151                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
6152                 warning_at (init_loc, OPT_Wc___compat,
6153                             ("initializer-string for array chars "
6154                              "is too long for C++"));
6155             }
6156
6157           return inside_init;
6158         }
6159       else if (INTEGRAL_TYPE_P (typ1))
6160         {
6161           error_init ("array of inappropriate type initialized "
6162                       "from string constant");
6163           return error_mark_node;
6164         }
6165     }
6166
6167   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
6168      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
6169      below and handle as a constructor.  */
6170   if (code == VECTOR_TYPE
6171       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
6172       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
6173       && TREE_CONSTANT (inside_init))
6174     {
6175       if (TREE_CODE (inside_init) == VECTOR_CST
6176           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6177                         TYPE_MAIN_VARIANT (type)))
6178         return inside_init;
6179
6180       if (TREE_CODE (inside_init) == CONSTRUCTOR)
6181         {
6182           unsigned HOST_WIDE_INT ix;
6183           tree value;
6184           bool constant_p = true;
6185
6186           /* Iterate through elements and check if all constructor
6187              elements are *_CSTs.  */
6188           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
6189             if (!CONSTANT_CLASS_P (value))
6190               {
6191                 constant_p = false;
6192                 break;
6193               }
6194
6195           if (constant_p)
6196             return build_vector_from_ctor (type,
6197                                            CONSTRUCTOR_ELTS (inside_init));
6198         }
6199     }
6200
6201   if (warn_sequence_point)
6202     verify_sequence_points (inside_init);
6203
6204   /* Any type can be initialized
6205      from an expression of the same type, optionally with braces.  */
6206
6207   if (inside_init && TREE_TYPE (inside_init) != 0
6208       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6209                      TYPE_MAIN_VARIANT (type))
6210           || (code == ARRAY_TYPE
6211               && comptypes (TREE_TYPE (inside_init), type))
6212           || (code == VECTOR_TYPE
6213               && comptypes (TREE_TYPE (inside_init), type))
6214           || (code == POINTER_TYPE
6215               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
6216               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
6217                             TREE_TYPE (type)))))
6218     {
6219       if (code == POINTER_TYPE)
6220         {
6221           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
6222             {
6223               if (TREE_CODE (inside_init) == STRING_CST
6224                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
6225                 inside_init = array_to_pointer_conversion
6226                   (init_loc, inside_init);
6227               else
6228                 {
6229                   error_init ("invalid use of non-lvalue array");
6230                   return error_mark_node;
6231                 }
6232             }
6233         }
6234
6235       if (code == VECTOR_TYPE)
6236         /* Although the types are compatible, we may require a
6237            conversion.  */
6238         inside_init = convert (type, inside_init);
6239
6240       if (require_constant
6241           && (code == VECTOR_TYPE || !flag_isoc99)
6242           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
6243         {
6244           /* As an extension, allow initializing objects with static storage
6245              duration with compound literals (which are then treated just as
6246              the brace enclosed list they contain).  Also allow this for
6247              vectors, as we can only assign them with compound literals.  */
6248           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
6249           inside_init = DECL_INITIAL (decl);
6250         }
6251
6252       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
6253           && TREE_CODE (inside_init) != CONSTRUCTOR)
6254         {
6255           error_init ("array initialized from non-constant array expression");
6256           return error_mark_node;
6257         }
6258
6259       /* Compound expressions can only occur here if -pedantic or
6260          -pedantic-errors is specified.  In the later case, we always want
6261          an error.  In the former case, we simply want a warning.  */
6262       if (require_constant && pedantic
6263           && TREE_CODE (inside_init) == COMPOUND_EXPR)
6264         {
6265           inside_init
6266             = valid_compound_expr_initializer (inside_init,
6267                                                TREE_TYPE (inside_init));
6268           if (inside_init == error_mark_node)
6269             error_init ("initializer element is not constant");
6270           else
6271             pedwarn_init (init_loc, OPT_pedantic,
6272                           "initializer element is not constant");
6273           if (flag_pedantic_errors)
6274             inside_init = error_mark_node;
6275         }
6276       else if (require_constant
6277                && !initializer_constant_valid_p (inside_init,
6278                                                  TREE_TYPE (inside_init)))
6279         {
6280           error_init ("initializer element is not constant");
6281           inside_init = error_mark_node;
6282         }
6283       else if (require_constant && !maybe_const)
6284         pedwarn_init (init_loc, 0,
6285                       "initializer element is not a constant expression");
6286
6287       /* Added to enable additional -Wmissing-format-attribute warnings.  */
6288       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
6289         inside_init = convert_for_assignment (init_loc, type, inside_init,
6290                                               origtype,
6291                                               ic_init, null_pointer_constant,
6292                                               NULL_TREE, NULL_TREE, 0);
6293       return inside_init;
6294     }
6295
6296   /* Handle scalar types, including conversions.  */
6297
6298   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
6299       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
6300       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
6301     {
6302       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
6303           && (TREE_CODE (init) == STRING_CST
6304               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
6305         inside_init = init = array_to_pointer_conversion (init_loc, init);
6306       if (semantic_type)
6307         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
6308                               inside_init);
6309       inside_init
6310         = convert_for_assignment (init_loc, type, inside_init, origtype,
6311                                   ic_init, null_pointer_constant,
6312                                   NULL_TREE, NULL_TREE, 0);
6313
6314       /* Check to see if we have already given an error message.  */
6315       if (inside_init == error_mark_node)
6316         ;
6317       else if (require_constant && !TREE_CONSTANT (inside_init))
6318         {
6319           error_init ("initializer element is not constant");
6320           inside_init = error_mark_node;
6321         }
6322       else if (require_constant
6323                && !initializer_constant_valid_p (inside_init,
6324                                                  TREE_TYPE (inside_init)))
6325         {
6326           error_init ("initializer element is not computable at load time");
6327           inside_init = error_mark_node;
6328         }
6329       else if (require_constant && !maybe_const)
6330         pedwarn_init (init_loc, 0,
6331                       "initializer element is not a constant expression");
6332
6333       return inside_init;
6334     }
6335
6336   /* Come here only for records and arrays.  */
6337
6338   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
6339     {
6340       error_init ("variable-sized object may not be initialized");
6341       return error_mark_node;
6342     }
6343
6344   error_init ("invalid initializer");
6345   return error_mark_node;
6346 }
6347 \f
6348 /* Handle initializers that use braces.  */
6349
6350 /* Type of object we are accumulating a constructor for.
6351    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
6352 static tree constructor_type;
6353
6354 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
6355    left to fill.  */
6356 static tree constructor_fields;
6357
6358 /* For an ARRAY_TYPE, this is the specified index
6359    at which to store the next element we get.  */
6360 static tree constructor_index;
6361
6362 /* For an ARRAY_TYPE, this is the maximum index.  */
6363 static tree constructor_max_index;
6364
6365 /* For a RECORD_TYPE, this is the first field not yet written out.  */
6366 static tree constructor_unfilled_fields;
6367
6368 /* For an ARRAY_TYPE, this is the index of the first element
6369    not yet written out.  */
6370 static tree constructor_unfilled_index;
6371
6372 /* In a RECORD_TYPE, the byte index of the next consecutive field.
6373    This is so we can generate gaps between fields, when appropriate.  */
6374 static tree constructor_bit_index;
6375
6376 /* If we are saving up the elements rather than allocating them,
6377    this is the list of elements so far (in reverse order,
6378    most recent first).  */
6379 static VEC(constructor_elt,gc) *constructor_elements;
6380
6381 /* 1 if constructor should be incrementally stored into a constructor chain,
6382    0 if all the elements should be kept in AVL tree.  */
6383 static int constructor_incremental;
6384
6385 /* 1 if so far this constructor's elements are all compile-time constants.  */
6386 static int constructor_constant;
6387
6388 /* 1 if so far this constructor's elements are all valid address constants.  */
6389 static int constructor_simple;
6390
6391 /* 1 if this constructor has an element that cannot be part of a
6392    constant expression.  */
6393 static int constructor_nonconst;
6394
6395 /* 1 if this constructor is erroneous so far.  */
6396 static int constructor_erroneous;
6397
6398 /* Structure for managing pending initializer elements, organized as an
6399    AVL tree.  */
6400
6401 struct init_node
6402 {
6403   struct init_node *left, *right;
6404   struct init_node *parent;
6405   int balance;
6406   tree purpose;
6407   tree value;
6408   tree origtype;
6409 };
6410
6411 /* Tree of pending elements at this constructor level.
6412    These are elements encountered out of order
6413    which belong at places we haven't reached yet in actually
6414    writing the output.
6415    Will never hold tree nodes across GC runs.  */
6416 static struct init_node *constructor_pending_elts;
6417
6418 /* The SPELLING_DEPTH of this constructor.  */
6419 static int constructor_depth;
6420
6421 /* DECL node for which an initializer is being read.
6422    0 means we are reading a constructor expression
6423    such as (struct foo) {...}.  */
6424 static tree constructor_decl;
6425
6426 /* Nonzero if this is an initializer for a top-level decl.  */
6427 static int constructor_top_level;
6428
6429 /* Nonzero if there were any member designators in this initializer.  */
6430 static int constructor_designated;
6431
6432 /* Nesting depth of designator list.  */
6433 static int designator_depth;
6434
6435 /* Nonzero if there were diagnosed errors in this designator list.  */
6436 static int designator_erroneous;
6437
6438 \f
6439 /* This stack has a level for each implicit or explicit level of
6440    structuring in the initializer, including the outermost one.  It
6441    saves the values of most of the variables above.  */
6442
6443 struct constructor_range_stack;
6444
6445 struct constructor_stack
6446 {
6447   struct constructor_stack *next;
6448   tree type;
6449   tree fields;
6450   tree index;
6451   tree max_index;
6452   tree unfilled_index;
6453   tree unfilled_fields;
6454   tree bit_index;
6455   VEC(constructor_elt,gc) *elements;
6456   struct init_node *pending_elts;
6457   int offset;
6458   int depth;
6459   /* If value nonzero, this value should replace the entire
6460      constructor at this level.  */
6461   struct c_expr replacement_value;
6462   struct constructor_range_stack *range_stack;
6463   char constant;
6464   char simple;
6465   char nonconst;
6466   char implicit;
6467   char erroneous;
6468   char outer;
6469   char incremental;
6470   char designated;
6471 };
6472
6473 static struct constructor_stack *constructor_stack;
6474
6475 /* This stack represents designators from some range designator up to
6476    the last designator in the list.  */
6477
6478 struct constructor_range_stack
6479 {
6480   struct constructor_range_stack *next, *prev;
6481   struct constructor_stack *stack;
6482   tree range_start;
6483   tree index;
6484   tree range_end;
6485   tree fields;
6486 };
6487
6488 static struct constructor_range_stack *constructor_range_stack;
6489
6490 /* This stack records separate initializers that are nested.
6491    Nested initializers can't happen in ANSI C, but GNU C allows them
6492    in cases like { ... (struct foo) { ... } ... }.  */
6493
6494 struct initializer_stack
6495 {
6496   struct initializer_stack *next;
6497   tree decl;
6498   struct constructor_stack *constructor_stack;
6499   struct constructor_range_stack *constructor_range_stack;
6500   VEC(constructor_elt,gc) *elements;
6501   struct spelling *spelling;
6502   struct spelling *spelling_base;
6503   int spelling_size;
6504   char top_level;
6505   char require_constant_value;
6506   char require_constant_elements;
6507 };
6508
6509 static struct initializer_stack *initializer_stack;
6510 \f
6511 /* Prepare to parse and output the initializer for variable DECL.  */
6512
6513 void
6514 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
6515 {
6516   const char *locus;
6517   struct initializer_stack *p = XNEW (struct initializer_stack);
6518
6519   p->decl = constructor_decl;
6520   p->require_constant_value = require_constant_value;
6521   p->require_constant_elements = require_constant_elements;
6522   p->constructor_stack = constructor_stack;
6523   p->constructor_range_stack = constructor_range_stack;
6524   p->elements = constructor_elements;
6525   p->spelling = spelling;
6526   p->spelling_base = spelling_base;
6527   p->spelling_size = spelling_size;
6528   p->top_level = constructor_top_level;
6529   p->next = initializer_stack;
6530   initializer_stack = p;
6531
6532   constructor_decl = decl;
6533   constructor_designated = 0;
6534   constructor_top_level = top_level;
6535
6536   if (decl != 0 && decl != error_mark_node)
6537     {
6538       require_constant_value = TREE_STATIC (decl);
6539       require_constant_elements
6540         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
6541            /* For a scalar, you can always use any value to initialize,
6542               even within braces.  */
6543            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
6544                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
6545                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
6546                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
6547       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
6548     }
6549   else
6550     {
6551       require_constant_value = 0;
6552       require_constant_elements = 0;
6553       locus = _("(anonymous)");
6554     }
6555
6556   constructor_stack = 0;
6557   constructor_range_stack = 0;
6558
6559   missing_braces_mentioned = 0;
6560
6561   spelling_base = 0;
6562   spelling_size = 0;
6563   RESTORE_SPELLING_DEPTH (0);
6564
6565   if (locus)
6566     push_string (locus);
6567 }
6568
6569 void
6570 finish_init (void)
6571 {
6572   struct initializer_stack *p = initializer_stack;
6573
6574   /* Free the whole constructor stack of this initializer.  */
6575   while (constructor_stack)
6576     {
6577       struct constructor_stack *q = constructor_stack;
6578       constructor_stack = q->next;
6579       free (q);
6580     }
6581
6582   gcc_assert (!constructor_range_stack);
6583
6584   /* Pop back to the data of the outer initializer (if any).  */
6585   free (spelling_base);
6586
6587   constructor_decl = p->decl;
6588   require_constant_value = p->require_constant_value;
6589   require_constant_elements = p->require_constant_elements;
6590   constructor_stack = p->constructor_stack;
6591   constructor_range_stack = p->constructor_range_stack;
6592   constructor_elements = p->elements;
6593   spelling = p->spelling;
6594   spelling_base = p->spelling_base;
6595   spelling_size = p->spelling_size;
6596   constructor_top_level = p->top_level;
6597   initializer_stack = p->next;
6598   free (p);
6599 }
6600 \f
6601 /* Call here when we see the initializer is surrounded by braces.
6602    This is instead of a call to push_init_level;
6603    it is matched by a call to pop_init_level.
6604
6605    TYPE is the type to initialize, for a constructor expression.
6606    For an initializer for a decl, TYPE is zero.  */
6607
6608 void
6609 really_start_incremental_init (tree type)
6610 {
6611   struct constructor_stack *p = XNEW (struct constructor_stack);
6612
6613   if (type == 0)
6614     type = TREE_TYPE (constructor_decl);
6615
6616   if (TREE_CODE (type) == VECTOR_TYPE
6617       && TYPE_VECTOR_OPAQUE (type))
6618     error ("opaque vector types cannot be initialized");
6619
6620   p->type = constructor_type;
6621   p->fields = constructor_fields;
6622   p->index = constructor_index;
6623   p->max_index = constructor_max_index;
6624   p->unfilled_index = constructor_unfilled_index;
6625   p->unfilled_fields = constructor_unfilled_fields;
6626   p->bit_index = constructor_bit_index;
6627   p->elements = constructor_elements;
6628   p->constant = constructor_constant;
6629   p->simple = constructor_simple;
6630   p->nonconst = constructor_nonconst;
6631   p->erroneous = constructor_erroneous;
6632   p->pending_elts = constructor_pending_elts;
6633   p->depth = constructor_depth;
6634   p->replacement_value.value = 0;
6635   p->replacement_value.original_code = ERROR_MARK;
6636   p->replacement_value.original_type = NULL;
6637   p->implicit = 0;
6638   p->range_stack = 0;
6639   p->outer = 0;
6640   p->incremental = constructor_incremental;
6641   p->designated = constructor_designated;
6642   p->next = 0;
6643   constructor_stack = p;
6644
6645   constructor_constant = 1;
6646   constructor_simple = 1;
6647   constructor_nonconst = 0;
6648   constructor_depth = SPELLING_DEPTH ();
6649   constructor_elements = 0;
6650   constructor_pending_elts = 0;
6651   constructor_type = type;
6652   constructor_incremental = 1;
6653   constructor_designated = 0;
6654   designator_depth = 0;
6655   designator_erroneous = 0;
6656
6657   if (TREE_CODE (constructor_type) == RECORD_TYPE
6658       || TREE_CODE (constructor_type) == UNION_TYPE)
6659     {
6660       constructor_fields = TYPE_FIELDS (constructor_type);
6661       /* Skip any nameless bit fields at the beginning.  */
6662       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6663              && DECL_NAME (constructor_fields) == 0)
6664         constructor_fields = DECL_CHAIN (constructor_fields);
6665
6666       constructor_unfilled_fields = constructor_fields;
6667       constructor_bit_index = bitsize_zero_node;
6668     }
6669   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6670     {
6671       if (TYPE_DOMAIN (constructor_type))
6672         {
6673           constructor_max_index
6674             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6675
6676           /* Detect non-empty initializations of zero-length arrays.  */
6677           if (constructor_max_index == NULL_TREE
6678               && TYPE_SIZE (constructor_type))
6679             constructor_max_index = integer_minus_one_node;
6680
6681           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6682              to initialize VLAs will cause a proper error; avoid tree
6683              checking errors as well by setting a safe value.  */
6684           if (constructor_max_index
6685               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6686             constructor_max_index = integer_minus_one_node;
6687
6688           constructor_index
6689             = convert (bitsizetype,
6690                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6691         }
6692       else
6693         {
6694           constructor_index = bitsize_zero_node;
6695           constructor_max_index = NULL_TREE;
6696         }
6697
6698       constructor_unfilled_index = constructor_index;
6699     }
6700   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6701     {
6702       /* Vectors are like simple fixed-size arrays.  */
6703       constructor_max_index =
6704         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6705       constructor_index = bitsize_zero_node;
6706       constructor_unfilled_index = constructor_index;
6707     }
6708   else
6709     {
6710       /* Handle the case of int x = {5}; */
6711       constructor_fields = constructor_type;
6712       constructor_unfilled_fields = constructor_type;
6713     }
6714 }
6715 \f
6716 /* Push down into a subobject, for initialization.
6717    If this is for an explicit set of braces, IMPLICIT is 0.
6718    If it is because the next element belongs at a lower level,
6719    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6720
6721 void
6722 push_init_level (int implicit, struct obstack * braced_init_obstack)
6723 {
6724   struct constructor_stack *p;
6725   tree value = NULL_TREE;
6726
6727   /* If we've exhausted any levels that didn't have braces,
6728      pop them now.  If implicit == 1, this will have been done in
6729      process_init_element; do not repeat it here because in the case
6730      of excess initializers for an empty aggregate this leads to an
6731      infinite cycle of popping a level and immediately recreating
6732      it.  */
6733   if (implicit != 1)
6734     {
6735       while (constructor_stack->implicit)
6736         {
6737           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6738                || TREE_CODE (constructor_type) == UNION_TYPE)
6739               && constructor_fields == 0)
6740             process_init_element (pop_init_level (1, braced_init_obstack),
6741                                   true, braced_init_obstack);
6742           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6743                    && constructor_max_index
6744                    && tree_int_cst_lt (constructor_max_index,
6745                                        constructor_index))
6746             process_init_element (pop_init_level (1, braced_init_obstack),
6747                                   true, braced_init_obstack);
6748           else
6749             break;
6750         }
6751     }
6752
6753   /* Unless this is an explicit brace, we need to preserve previous
6754      content if any.  */
6755   if (implicit)
6756     {
6757       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6758            || TREE_CODE (constructor_type) == UNION_TYPE)
6759           && constructor_fields)
6760         value = find_init_member (constructor_fields, braced_init_obstack);
6761       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6762         value = find_init_member (constructor_index, braced_init_obstack);
6763     }
6764
6765   p = XNEW (struct constructor_stack);
6766   p->type = constructor_type;
6767   p->fields = constructor_fields;
6768   p->index = constructor_index;
6769   p->max_index = constructor_max_index;
6770   p->unfilled_index = constructor_unfilled_index;
6771   p->unfilled_fields = constructor_unfilled_fields;
6772   p->bit_index = constructor_bit_index;
6773   p->elements = constructor_elements;
6774   p->constant = constructor_constant;
6775   p->simple = constructor_simple;
6776   p->nonconst = constructor_nonconst;
6777   p->erroneous = constructor_erroneous;
6778   p->pending_elts = constructor_pending_elts;
6779   p->depth = constructor_depth;
6780   p->replacement_value.value = 0;
6781   p->replacement_value.original_code = ERROR_MARK;
6782   p->replacement_value.original_type = NULL;
6783   p->implicit = implicit;
6784   p->outer = 0;
6785   p->incremental = constructor_incremental;
6786   p->designated = constructor_designated;
6787   p->next = constructor_stack;
6788   p->range_stack = 0;
6789   constructor_stack = p;
6790
6791   constructor_constant = 1;
6792   constructor_simple = 1;
6793   constructor_nonconst = 0;
6794   constructor_depth = SPELLING_DEPTH ();
6795   constructor_elements = 0;
6796   constructor_incremental = 1;
6797   constructor_designated = 0;
6798   constructor_pending_elts = 0;
6799   if (!implicit)
6800     {
6801       p->range_stack = constructor_range_stack;
6802       constructor_range_stack = 0;
6803       designator_depth = 0;
6804       designator_erroneous = 0;
6805     }
6806
6807   /* Don't die if an entire brace-pair level is superfluous
6808      in the containing level.  */
6809   if (constructor_type == 0)
6810     ;
6811   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6812            || TREE_CODE (constructor_type) == UNION_TYPE)
6813     {
6814       /* Don't die if there are extra init elts at the end.  */
6815       if (constructor_fields == 0)
6816         constructor_type = 0;
6817       else
6818         {
6819           constructor_type = TREE_TYPE (constructor_fields);
6820           push_member_name (constructor_fields);
6821           constructor_depth++;
6822         }
6823     }
6824   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6825     {
6826       constructor_type = TREE_TYPE (constructor_type);
6827       push_array_bounds (tree_low_cst (constructor_index, 1));
6828       constructor_depth++;
6829     }
6830
6831   if (constructor_type == 0)
6832     {
6833       error_init ("extra brace group at end of initializer");
6834       constructor_fields = 0;
6835       constructor_unfilled_fields = 0;
6836       return;
6837     }
6838
6839   if (value && TREE_CODE (value) == CONSTRUCTOR)
6840     {
6841       constructor_constant = TREE_CONSTANT (value);
6842       constructor_simple = TREE_STATIC (value);
6843       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6844       constructor_elements = CONSTRUCTOR_ELTS (value);
6845       if (!VEC_empty (constructor_elt, constructor_elements)
6846           && (TREE_CODE (constructor_type) == RECORD_TYPE
6847               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6848         set_nonincremental_init (braced_init_obstack);
6849     }
6850
6851   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6852     {
6853       missing_braces_mentioned = 1;
6854       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6855     }
6856
6857   if (TREE_CODE (constructor_type) == RECORD_TYPE
6858            || TREE_CODE (constructor_type) == UNION_TYPE)
6859     {
6860       constructor_fields = TYPE_FIELDS (constructor_type);
6861       /* Skip any nameless bit fields at the beginning.  */
6862       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6863              && DECL_NAME (constructor_fields) == 0)
6864         constructor_fields = DECL_CHAIN (constructor_fields);
6865
6866       constructor_unfilled_fields = constructor_fields;
6867       constructor_bit_index = bitsize_zero_node;
6868     }
6869   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6870     {
6871       /* Vectors are like simple fixed-size arrays.  */
6872       constructor_max_index =
6873         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6874       constructor_index = convert (bitsizetype, integer_zero_node);
6875       constructor_unfilled_index = constructor_index;
6876     }
6877   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6878     {
6879       if (TYPE_DOMAIN (constructor_type))
6880         {
6881           constructor_max_index
6882             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6883
6884           /* Detect non-empty initializations of zero-length arrays.  */
6885           if (constructor_max_index == NULL_TREE
6886               && TYPE_SIZE (constructor_type))
6887             constructor_max_index = integer_minus_one_node;
6888
6889           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6890              to initialize VLAs will cause a proper error; avoid tree
6891              checking errors as well by setting a safe value.  */
6892           if (constructor_max_index
6893               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6894             constructor_max_index = integer_minus_one_node;
6895
6896           constructor_index
6897             = convert (bitsizetype,
6898                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6899         }
6900       else
6901         constructor_index = bitsize_zero_node;
6902
6903       constructor_unfilled_index = constructor_index;
6904       if (value && TREE_CODE (value) == STRING_CST)
6905         {
6906           /* We need to split the char/wchar array into individual
6907              characters, so that we don't have to special case it
6908              everywhere.  */
6909           set_nonincremental_init_from_string (value, braced_init_obstack);
6910         }
6911     }
6912   else
6913     {
6914       if (constructor_type != error_mark_node)
6915         warning_init (0, "braces around scalar initializer");
6916       constructor_fields = constructor_type;
6917       constructor_unfilled_fields = constructor_type;
6918     }
6919 }
6920
6921 /* At the end of an implicit or explicit brace level,
6922    finish up that level of constructor.  If a single expression
6923    with redundant braces initialized that level, return the
6924    c_expr structure for that expression.  Otherwise, the original_code
6925    element is set to ERROR_MARK.
6926    If we were outputting the elements as they are read, return 0 as the value
6927    from inner levels (process_init_element ignores that),
6928    but return error_mark_node as the value from the outermost level
6929    (that's what we want to put in DECL_INITIAL).
6930    Otherwise, return a CONSTRUCTOR expression as the value.  */
6931
6932 struct c_expr
6933 pop_init_level (int implicit, struct obstack * braced_init_obstack)
6934 {
6935   struct constructor_stack *p;
6936   struct c_expr ret;
6937   ret.value = 0;
6938   ret.original_code = ERROR_MARK;
6939   ret.original_type = NULL;
6940
6941   if (implicit == 0)
6942     {
6943       /* When we come to an explicit close brace,
6944          pop any inner levels that didn't have explicit braces.  */
6945       while (constructor_stack->implicit)
6946         {
6947           process_init_element (pop_init_level (1, braced_init_obstack),
6948                                 true, braced_init_obstack);
6949         }
6950       gcc_assert (!constructor_range_stack);
6951     }
6952
6953   /* Now output all pending elements.  */
6954   constructor_incremental = 1;
6955   output_pending_init_elements (1, braced_init_obstack);
6956
6957   p = constructor_stack;
6958
6959   /* Error for initializing a flexible array member, or a zero-length
6960      array member in an inappropriate context.  */
6961   if (constructor_type && constructor_fields
6962       && TREE_CODE (constructor_type) == ARRAY_TYPE
6963       && TYPE_DOMAIN (constructor_type)
6964       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6965     {
6966       /* Silently discard empty initializations.  The parser will
6967          already have pedwarned for empty brackets.  */
6968       if (integer_zerop (constructor_unfilled_index))
6969         constructor_type = NULL_TREE;
6970       else
6971         {
6972           gcc_assert (!TYPE_SIZE (constructor_type));
6973
6974           if (constructor_depth > 2)
6975             error_init ("initialization of flexible array member in a nested context");
6976           else
6977             pedwarn_init (input_location, OPT_pedantic,
6978                           "initialization of a flexible array member");
6979
6980           /* We have already issued an error message for the existence
6981              of a flexible array member not at the end of the structure.
6982              Discard the initializer so that we do not die later.  */
6983           if (DECL_CHAIN (constructor_fields) != NULL_TREE)
6984             constructor_type = NULL_TREE;
6985         }
6986     }
6987
6988   /* Warn when some struct elements are implicitly initialized to zero.  */
6989   if (warn_missing_field_initializers
6990       && constructor_type
6991       && TREE_CODE (constructor_type) == RECORD_TYPE
6992       && constructor_unfilled_fields)
6993     {
6994         /* Do not warn for flexible array members or zero-length arrays.  */
6995         while (constructor_unfilled_fields
6996                && (!DECL_SIZE (constructor_unfilled_fields)
6997                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6998           constructor_unfilled_fields = DECL_CHAIN (constructor_unfilled_fields);
6999
7000         /* Do not warn if this level of the initializer uses member
7001            designators; it is likely to be deliberate.  */
7002         if (constructor_unfilled_fields && !constructor_designated)
7003           {
7004             push_member_name (constructor_unfilled_fields);
7005             warning_init (OPT_Wmissing_field_initializers,
7006                           "missing initializer");
7007             RESTORE_SPELLING_DEPTH (constructor_depth);
7008           }
7009     }
7010
7011   /* Pad out the end of the structure.  */
7012   if (p->replacement_value.value)
7013     /* If this closes a superfluous brace pair,
7014        just pass out the element between them.  */
7015     ret = p->replacement_value;
7016   else if (constructor_type == 0)
7017     ;
7018   else if (TREE_CODE (constructor_type) != RECORD_TYPE
7019            && TREE_CODE (constructor_type) != UNION_TYPE
7020            && TREE_CODE (constructor_type) != ARRAY_TYPE
7021            && TREE_CODE (constructor_type) != VECTOR_TYPE)
7022     {
7023       /* A nonincremental scalar initializer--just return
7024          the element, after verifying there is just one.  */
7025       if (VEC_empty (constructor_elt,constructor_elements))
7026         {
7027           if (!constructor_erroneous)
7028             error_init ("empty scalar initializer");
7029           ret.value = error_mark_node;
7030         }
7031       else if (VEC_length (constructor_elt,constructor_elements) != 1)
7032         {
7033           error_init ("extra elements in scalar initializer");
7034           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
7035         }
7036       else
7037         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
7038     }
7039   else
7040     {
7041       if (constructor_erroneous)
7042         ret.value = error_mark_node;
7043       else
7044         {
7045           ret.value = build_constructor (constructor_type,
7046                                          constructor_elements);
7047           if (constructor_constant)
7048             TREE_CONSTANT (ret.value) = 1;
7049           if (constructor_constant && constructor_simple)
7050             TREE_STATIC (ret.value) = 1;
7051           if (constructor_nonconst)
7052             CONSTRUCTOR_NON_CONST (ret.value) = 1;
7053         }
7054     }
7055
7056   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
7057     {
7058       if (constructor_nonconst)
7059         ret.original_code = C_MAYBE_CONST_EXPR;
7060       else if (ret.original_code == C_MAYBE_CONST_EXPR)
7061         ret.original_code = ERROR_MARK;
7062     }
7063
7064   constructor_type = p->type;
7065   constructor_fields = p->fields;
7066   constructor_index = p->index;
7067   constructor_max_index = p->max_index;
7068   constructor_unfilled_index = p->unfilled_index;
7069   constructor_unfilled_fields = p->unfilled_fields;
7070   constructor_bit_index = p->bit_index;
7071   constructor_elements = p->elements;
7072   constructor_constant = p->constant;
7073   constructor_simple = p->simple;
7074   constructor_nonconst = p->nonconst;
7075   constructor_erroneous = p->erroneous;
7076   constructor_incremental = p->incremental;
7077   constructor_designated = p->designated;
7078   constructor_pending_elts = p->pending_elts;
7079   constructor_depth = p->depth;
7080   if (!p->implicit)
7081     constructor_range_stack = p->range_stack;
7082   RESTORE_SPELLING_DEPTH (constructor_depth);
7083
7084   constructor_stack = p->next;
7085   free (p);
7086
7087   if (ret.value == 0 && constructor_stack == 0)
7088     ret.value = error_mark_node;
7089   return ret;
7090 }
7091
7092 /* Common handling for both array range and field name designators.
7093    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
7094
7095 static int
7096 set_designator (int array, struct obstack * braced_init_obstack)
7097 {
7098   tree subtype;
7099   enum tree_code subcode;
7100
7101   /* Don't die if an entire brace-pair level is superfluous
7102      in the containing level.  */
7103   if (constructor_type == 0)
7104     return 1;
7105
7106   /* If there were errors in this designator list already, bail out
7107      silently.  */
7108   if (designator_erroneous)
7109     return 1;
7110
7111   if (!designator_depth)
7112     {
7113       gcc_assert (!constructor_range_stack);
7114
7115       /* Designator list starts at the level of closest explicit
7116          braces.  */
7117       while (constructor_stack->implicit)
7118         {
7119           process_init_element (pop_init_level (1, braced_init_obstack),
7120                                 true, braced_init_obstack);
7121         }
7122       constructor_designated = 1;
7123       return 0;
7124     }
7125
7126   switch (TREE_CODE (constructor_type))
7127     {
7128     case  RECORD_TYPE:
7129     case  UNION_TYPE:
7130       subtype = TREE_TYPE (constructor_fields);
7131       if (subtype != error_mark_node)
7132         subtype = TYPE_MAIN_VARIANT (subtype);
7133       break;
7134     case ARRAY_TYPE:
7135       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7136       break;
7137     default:
7138       gcc_unreachable ();
7139     }
7140
7141   subcode = TREE_CODE (subtype);
7142   if (array && subcode != ARRAY_TYPE)
7143     {
7144       error_init ("array index in non-array initializer");
7145       return 1;
7146     }
7147   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
7148     {
7149       error_init ("field name not in record or union initializer");
7150       return 1;
7151     }
7152
7153   constructor_designated = 1;
7154   push_init_level (2, braced_init_obstack);
7155   return 0;
7156 }
7157
7158 /* If there are range designators in designator list, push a new designator
7159    to constructor_range_stack.  RANGE_END is end of such stack range or
7160    NULL_TREE if there is no range designator at this level.  */
7161
7162 static void
7163 push_range_stack (tree range_end, struct obstack * braced_init_obstack)
7164 {
7165   struct constructor_range_stack *p;
7166
7167   p = (struct constructor_range_stack *)
7168     obstack_alloc (braced_init_obstack,
7169                    sizeof (struct constructor_range_stack));
7170   p->prev = constructor_range_stack;
7171   p->next = 0;
7172   p->fields = constructor_fields;
7173   p->range_start = constructor_index;
7174   p->index = constructor_index;
7175   p->stack = constructor_stack;
7176   p->range_end = range_end;
7177   if (constructor_range_stack)
7178     constructor_range_stack->next = p;
7179   constructor_range_stack = p;
7180 }
7181
7182 /* Within an array initializer, specify the next index to be initialized.
7183    FIRST is that index.  If LAST is nonzero, then initialize a range
7184    of indices, running from FIRST through LAST.  */
7185
7186 void
7187 set_init_index (tree first, tree last,
7188                 struct obstack * braced_init_obstack)
7189 {
7190   if (set_designator (1, braced_init_obstack))
7191     return;
7192
7193   designator_erroneous = 1;
7194
7195   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
7196       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
7197     {
7198       error_init ("array index in initializer not of integer type");
7199       return;
7200     }
7201
7202   if (TREE_CODE (first) != INTEGER_CST)
7203     {
7204       first = c_fully_fold (first, false, NULL);
7205       if (TREE_CODE (first) == INTEGER_CST)
7206         pedwarn_init (input_location, OPT_pedantic,
7207                       "array index in initializer is not "
7208                       "an integer constant expression");
7209     }
7210
7211   if (last && TREE_CODE (last) != INTEGER_CST)
7212     {
7213       last = c_fully_fold (last, false, NULL);
7214       if (TREE_CODE (last) == INTEGER_CST)
7215         pedwarn_init (input_location, OPT_pedantic,
7216                       "array index in initializer is not "
7217                       "an integer constant expression");
7218     }
7219
7220   if (TREE_CODE (first) != INTEGER_CST)
7221     error_init ("nonconstant array index in initializer");
7222   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
7223     error_init ("nonconstant array index in initializer");
7224   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
7225     error_init ("array index in non-array initializer");
7226   else if (tree_int_cst_sgn (first) == -1)
7227     error_init ("array index in initializer exceeds array bounds");
7228   else if (constructor_max_index
7229            && tree_int_cst_lt (constructor_max_index, first))
7230     error_init ("array index in initializer exceeds array bounds");
7231   else
7232     {
7233       constant_expression_warning (first);
7234       if (last)
7235         constant_expression_warning (last);
7236       constructor_index = convert (bitsizetype, first);
7237
7238       if (last)
7239         {
7240           if (tree_int_cst_equal (first, last))
7241             last = 0;
7242           else if (tree_int_cst_lt (last, first))
7243             {
7244               error_init ("empty index range in initializer");
7245               last = 0;
7246             }
7247           else
7248             {
7249               last = convert (bitsizetype, last);
7250               if (constructor_max_index != 0
7251                   && tree_int_cst_lt (constructor_max_index, last))
7252                 {
7253                   error_init ("array index range in initializer exceeds array bounds");
7254                   last = 0;
7255                 }
7256             }
7257         }
7258
7259       designator_depth++;
7260       designator_erroneous = 0;
7261       if (constructor_range_stack || last)
7262         push_range_stack (last, braced_init_obstack);
7263     }
7264 }
7265
7266 /* Within a struct initializer, specify the next field to be initialized.  */
7267
7268 void
7269 set_init_label (tree fieldname, struct obstack * braced_init_obstack)
7270 {
7271   tree field;
7272
7273   if (set_designator (0, braced_init_obstack))
7274     return;
7275
7276   designator_erroneous = 1;
7277
7278   if (TREE_CODE (constructor_type) != RECORD_TYPE
7279       && TREE_CODE (constructor_type) != UNION_TYPE)
7280     {
7281       error_init ("field name not in record or union initializer");
7282       return;
7283     }
7284
7285   field = lookup_field (constructor_type, fieldname);
7286
7287   if (field == 0)
7288     error ("unknown field %qE specified in initializer", fieldname);
7289   else
7290     do
7291       {
7292         constructor_fields = TREE_VALUE (field);
7293         designator_depth++;
7294         designator_erroneous = 0;
7295         if (constructor_range_stack)
7296           push_range_stack (NULL_TREE, braced_init_obstack);
7297         field = TREE_CHAIN (field);
7298         if (field)
7299           {
7300             if (set_designator (0, braced_init_obstack))
7301               return;
7302           }
7303       }
7304     while (field != NULL_TREE);
7305 }
7306 \f
7307 /* Add a new initializer to the tree of pending initializers.  PURPOSE
7308    identifies the initializer, either array index or field in a structure.
7309    VALUE is the value of that index or field.  If ORIGTYPE is not
7310    NULL_TREE, it is the original type of VALUE.
7311
7312    IMPLICIT is true if value comes from pop_init_level (1),
7313    the new initializer has been merged with the existing one
7314    and thus no warnings should be emitted about overriding an
7315    existing initializer.  */
7316
7317 static void
7318 add_pending_init (tree purpose, tree value, tree origtype, bool implicit,
7319                   struct obstack * braced_init_obstack)
7320 {
7321   struct init_node *p, **q, *r;
7322
7323   q = &constructor_pending_elts;
7324   p = 0;
7325
7326   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7327     {
7328       while (*q != 0)
7329         {
7330           p = *q;
7331           if (tree_int_cst_lt (purpose, p->purpose))
7332             q = &p->left;
7333           else if (tree_int_cst_lt (p->purpose, purpose))
7334             q = &p->right;
7335           else
7336             {
7337               if (!implicit)
7338                 {
7339                   if (TREE_SIDE_EFFECTS (p->value))
7340                     warning_init (0, "initialized field with side-effects overwritten");
7341                   else if (warn_override_init)
7342                     warning_init (OPT_Woverride_init, "initialized field overwritten");
7343                 }
7344               p->value = value;
7345               p->origtype = origtype;
7346               return;
7347             }
7348         }
7349     }
7350   else
7351     {
7352       tree bitpos;
7353
7354       bitpos = bit_position (purpose);
7355       while (*q != NULL)
7356         {
7357           p = *q;
7358           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7359             q = &p->left;
7360           else if (p->purpose != purpose)
7361             q = &p->right;
7362           else
7363             {
7364               if (!implicit)
7365                 {
7366                   if (TREE_SIDE_EFFECTS (p->value))
7367                     warning_init (0, "initialized field with side-effects overwritten");
7368                   else if (warn_override_init)
7369                     warning_init (OPT_Woverride_init, "initialized field overwritten");
7370                 }
7371               p->value = value;
7372               p->origtype = origtype;
7373               return;
7374             }
7375         }
7376     }
7377
7378   r = (struct init_node *) obstack_alloc (braced_init_obstack,
7379                                           sizeof (struct init_node));
7380   r->purpose = purpose;
7381   r->value = value;
7382   r->origtype = origtype;
7383
7384   *q = r;
7385   r->parent = p;
7386   r->left = 0;
7387   r->right = 0;
7388   r->balance = 0;
7389
7390   while (p)
7391     {
7392       struct init_node *s;
7393
7394       if (r == p->left)
7395         {
7396           if (p->balance == 0)
7397             p->balance = -1;
7398           else if (p->balance < 0)
7399             {
7400               if (r->balance < 0)
7401                 {
7402                   /* L rotation.  */
7403                   p->left = r->right;
7404                   if (p->left)
7405                     p->left->parent = p;
7406                   r->right = p;
7407
7408                   p->balance = 0;
7409                   r->balance = 0;
7410
7411                   s = p->parent;
7412                   p->parent = r;
7413                   r->parent = s;
7414                   if (s)
7415                     {
7416                       if (s->left == p)
7417                         s->left = r;
7418                       else
7419                         s->right = r;
7420                     }
7421                   else
7422                     constructor_pending_elts = r;
7423                 }
7424               else
7425                 {
7426                   /* LR rotation.  */
7427                   struct init_node *t = r->right;
7428
7429                   r->right = t->left;
7430                   if (r->right)
7431                     r->right->parent = r;
7432                   t->left = r;
7433
7434                   p->left = t->right;
7435                   if (p->left)
7436                     p->left->parent = p;
7437                   t->right = p;
7438
7439                   p->balance = t->balance < 0;
7440                   r->balance = -(t->balance > 0);
7441                   t->balance = 0;
7442
7443                   s = p->parent;
7444                   p->parent = t;
7445                   r->parent = t;
7446                   t->parent = s;
7447                   if (s)
7448                     {
7449                       if (s->left == p)
7450                         s->left = t;
7451                       else
7452                         s->right = t;
7453                     }
7454                   else
7455                     constructor_pending_elts = t;
7456                 }
7457               break;
7458             }
7459           else
7460             {
7461               /* p->balance == +1; growth of left side balances the node.  */
7462               p->balance = 0;
7463               break;
7464             }
7465         }
7466       else /* r == p->right */
7467         {
7468           if (p->balance == 0)
7469             /* Growth propagation from right side.  */
7470             p->balance++;
7471           else if (p->balance > 0)
7472             {
7473               if (r->balance > 0)
7474                 {
7475                   /* R rotation.  */
7476                   p->right = r->left;
7477                   if (p->right)
7478                     p->right->parent = p;
7479                   r->left = p;
7480
7481                   p->balance = 0;
7482                   r->balance = 0;
7483
7484                   s = p->parent;
7485                   p->parent = r;
7486                   r->parent = s;
7487                   if (s)
7488                     {
7489                       if (s->left == p)
7490                         s->left = r;
7491                       else
7492                         s->right = r;
7493                     }
7494                   else
7495                     constructor_pending_elts = r;
7496                 }
7497               else /* r->balance == -1 */
7498                 {
7499                   /* RL rotation */
7500                   struct init_node *t = r->left;
7501
7502                   r->left = t->right;
7503                   if (r->left)
7504                     r->left->parent = r;
7505                   t->right = r;
7506
7507                   p->right = t->left;
7508                   if (p->right)
7509                     p->right->parent = p;
7510                   t->left = p;
7511
7512                   r->balance = (t->balance < 0);
7513                   p->balance = -(t->balance > 0);
7514                   t->balance = 0;
7515
7516                   s = p->parent;
7517                   p->parent = t;
7518                   r->parent = t;
7519                   t->parent = s;
7520                   if (s)
7521                     {
7522                       if (s->left == p)
7523                         s->left = t;
7524                       else
7525                         s->right = t;
7526                     }
7527                   else
7528                     constructor_pending_elts = t;
7529                 }
7530               break;
7531             }
7532           else
7533             {
7534               /* p->balance == -1; growth of right side balances the node.  */
7535               p->balance = 0;
7536               break;
7537             }
7538         }
7539
7540       r = p;
7541       p = p->parent;
7542     }
7543 }
7544
7545 /* Build AVL tree from a sorted chain.  */
7546
7547 static void
7548 set_nonincremental_init (struct obstack * braced_init_obstack)
7549 {
7550   unsigned HOST_WIDE_INT ix;
7551   tree index, value;
7552
7553   if (TREE_CODE (constructor_type) != RECORD_TYPE
7554       && TREE_CODE (constructor_type) != ARRAY_TYPE)
7555     return;
7556
7557   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
7558     {
7559       add_pending_init (index, value, NULL_TREE, false,
7560                         braced_init_obstack);
7561     }
7562   constructor_elements = 0;
7563   if (TREE_CODE (constructor_type) == RECORD_TYPE)
7564     {
7565       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
7566       /* Skip any nameless bit fields at the beginning.  */
7567       while (constructor_unfilled_fields != 0
7568              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7569              && DECL_NAME (constructor_unfilled_fields) == 0)
7570         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
7571
7572     }
7573   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7574     {
7575       if (TYPE_DOMAIN (constructor_type))
7576         constructor_unfilled_index
7577             = convert (bitsizetype,
7578                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
7579       else
7580         constructor_unfilled_index = bitsize_zero_node;
7581     }
7582   constructor_incremental = 0;
7583 }
7584
7585 /* Build AVL tree from a string constant.  */
7586
7587 static void
7588 set_nonincremental_init_from_string (tree str,
7589                                      struct obstack * braced_init_obstack)
7590 {
7591   tree value, purpose, type;
7592   HOST_WIDE_INT val[2];
7593   const char *p, *end;
7594   int byte, wchar_bytes, charwidth, bitpos;
7595
7596   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7597
7598   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7599   charwidth = TYPE_PRECISION (char_type_node);
7600   type = TREE_TYPE (constructor_type);
7601   p = TREE_STRING_POINTER (str);
7602   end = p + TREE_STRING_LENGTH (str);
7603
7604   for (purpose = bitsize_zero_node;
7605        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7606        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7607     {
7608       if (wchar_bytes == 1)
7609         {
7610           val[1] = (unsigned char) *p++;
7611           val[0] = 0;
7612         }
7613       else
7614         {
7615           val[0] = 0;
7616           val[1] = 0;
7617           for (byte = 0; byte < wchar_bytes; byte++)
7618             {
7619               if (BYTES_BIG_ENDIAN)
7620                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7621               else
7622                 bitpos = byte * charwidth;
7623               val[bitpos < HOST_BITS_PER_WIDE_INT]
7624                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7625                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7626             }
7627         }
7628
7629       if (!TYPE_UNSIGNED (type))
7630         {
7631           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7632           if (bitpos < HOST_BITS_PER_WIDE_INT)
7633             {
7634               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7635                 {
7636                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7637                   val[0] = -1;
7638                 }
7639             }
7640           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7641             {
7642               if (val[1] < 0)
7643                 val[0] = -1;
7644             }
7645           else if (val[0] & (((HOST_WIDE_INT) 1)
7646                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7647             val[0] |= ((HOST_WIDE_INT) -1)
7648                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7649         }
7650
7651       value = build_int_cst_wide (type, val[1], val[0]);
7652       add_pending_init (purpose, value, NULL_TREE, false,
7653                         braced_init_obstack);
7654     }
7655
7656   constructor_incremental = 0;
7657 }
7658
7659 /* Return value of FIELD in pending initializer or zero if the field was
7660    not initialized yet.  */
7661
7662 static tree
7663 find_init_member (tree field, struct obstack * braced_init_obstack)
7664 {
7665   struct init_node *p;
7666
7667   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7668     {
7669       if (constructor_incremental
7670           && tree_int_cst_lt (field, constructor_unfilled_index))
7671         set_nonincremental_init (braced_init_obstack);
7672
7673       p = constructor_pending_elts;
7674       while (p)
7675         {
7676           if (tree_int_cst_lt (field, p->purpose))
7677             p = p->left;
7678           else if (tree_int_cst_lt (p->purpose, field))
7679             p = p->right;
7680           else
7681             return p->value;
7682         }
7683     }
7684   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7685     {
7686       tree bitpos = bit_position (field);
7687
7688       if (constructor_incremental
7689           && (!constructor_unfilled_fields
7690               || tree_int_cst_lt (bitpos,
7691                                   bit_position (constructor_unfilled_fields))))
7692         set_nonincremental_init (braced_init_obstack);
7693
7694       p = constructor_pending_elts;
7695       while (p)
7696         {
7697           if (field == p->purpose)
7698             return p->value;
7699           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7700             p = p->left;
7701           else
7702             p = p->right;
7703         }
7704     }
7705   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7706     {
7707       if (!VEC_empty (constructor_elt, constructor_elements)
7708           && (VEC_last (constructor_elt, constructor_elements)->index
7709               == field))
7710         return VEC_last (constructor_elt, constructor_elements)->value;
7711     }
7712   return 0;
7713 }
7714
7715 /* "Output" the next constructor element.
7716    At top level, really output it to assembler code now.
7717    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7718    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7719    TYPE is the data type that the containing data type wants here.
7720    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7721    If VALUE is a string constant, STRICT_STRING is true if it is
7722    unparenthesized or we should not warn here for it being parenthesized.
7723    For other types of VALUE, STRICT_STRING is not used.
7724
7725    PENDING if non-nil means output pending elements that belong
7726    right after this element.  (PENDING is normally 1;
7727    it is 0 while outputting pending elements, to avoid recursion.)
7728
7729    IMPLICIT is true if value comes from pop_init_level (1),
7730    the new initializer has been merged with the existing one
7731    and thus no warnings should be emitted about overriding an
7732    existing initializer.  */
7733
7734 static void
7735 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7736                      tree field, int pending, bool implicit,
7737                      struct obstack * braced_init_obstack)
7738 {
7739   tree semantic_type = NULL_TREE;
7740   constructor_elt *celt;
7741   bool maybe_const = true;
7742   bool npc;
7743
7744   if (type == error_mark_node || value == error_mark_node)
7745     {
7746       constructor_erroneous = 1;
7747       return;
7748     }
7749   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7750       && (TREE_CODE (value) == STRING_CST
7751           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7752       && !(TREE_CODE (value) == STRING_CST
7753            && TREE_CODE (type) == ARRAY_TYPE
7754            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7755       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7756                      TYPE_MAIN_VARIANT (type)))
7757     value = array_to_pointer_conversion (input_location, value);
7758
7759   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7760       && require_constant_value && !flag_isoc99 && pending)
7761     {
7762       /* As an extension, allow initializing objects with static storage
7763          duration with compound literals (which are then treated just as
7764          the brace enclosed list they contain).  */
7765       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7766       value = DECL_INITIAL (decl);
7767     }
7768
7769   npc = null_pointer_constant_p (value);
7770   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7771     {
7772       semantic_type = TREE_TYPE (value);
7773       value = TREE_OPERAND (value, 0);
7774     }
7775   value = c_fully_fold (value, require_constant_value, &maybe_const);
7776
7777   if (value == error_mark_node)
7778     constructor_erroneous = 1;
7779   else if (!TREE_CONSTANT (value))
7780     constructor_constant = 0;
7781   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7782            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7783                 || TREE_CODE (constructor_type) == UNION_TYPE)
7784                && DECL_C_BIT_FIELD (field)
7785                && TREE_CODE (value) != INTEGER_CST))
7786     constructor_simple = 0;
7787   if (!maybe_const)
7788     constructor_nonconst = 1;
7789
7790   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7791     {
7792       if (require_constant_value)
7793         {
7794           error_init ("initializer element is not constant");
7795           value = error_mark_node;
7796         }
7797       else if (require_constant_elements)
7798         pedwarn (input_location, 0,
7799                  "initializer element is not computable at load time");
7800     }
7801   else if (!maybe_const
7802            && (require_constant_value || require_constant_elements))
7803     pedwarn_init (input_location, 0,
7804                   "initializer element is not a constant expression");
7805
7806   /* Issue -Wc++-compat warnings about initializing a bitfield with
7807      enum type.  */
7808   if (warn_cxx_compat
7809       && field != NULL_TREE
7810       && TREE_CODE (field) == FIELD_DECL
7811       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7812       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7813           != TYPE_MAIN_VARIANT (type))
7814       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7815     {
7816       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7817       if (checktype != error_mark_node
7818           && (TYPE_MAIN_VARIANT (checktype)
7819               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7820         warning_init (OPT_Wc___compat,
7821                       "enum conversion in initialization is invalid in C++");
7822     }
7823
7824   /* If this field is empty (and not at the end of structure),
7825      don't do anything other than checking the initializer.  */
7826   if (field
7827       && (TREE_TYPE (field) == error_mark_node
7828           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7829               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7830               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7831                   || DECL_CHAIN (field)))))
7832     return;
7833
7834   if (semantic_type)
7835     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7836   value = digest_init (input_location, type, value, origtype, npc,
7837                        strict_string, require_constant_value);
7838   if (value == error_mark_node)
7839     {
7840       constructor_erroneous = 1;
7841       return;
7842     }
7843   if (require_constant_value || require_constant_elements)
7844     constant_expression_warning (value);
7845
7846   /* If this element doesn't come next in sequence,
7847      put it on constructor_pending_elts.  */
7848   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7849       && (!constructor_incremental
7850           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7851     {
7852       if (constructor_incremental
7853           && tree_int_cst_lt (field, constructor_unfilled_index))
7854         set_nonincremental_init (braced_init_obstack);
7855
7856       add_pending_init (field, value, origtype, implicit,
7857                         braced_init_obstack);
7858       return;
7859     }
7860   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7861            && (!constructor_incremental
7862                || field != constructor_unfilled_fields))
7863     {
7864       /* We do this for records but not for unions.  In a union,
7865          no matter which field is specified, it can be initialized
7866          right away since it starts at the beginning of the union.  */
7867       if (constructor_incremental)
7868         {
7869           if (!constructor_unfilled_fields)
7870             set_nonincremental_init (braced_init_obstack);
7871           else
7872             {
7873               tree bitpos, unfillpos;
7874
7875               bitpos = bit_position (field);
7876               unfillpos = bit_position (constructor_unfilled_fields);
7877
7878               if (tree_int_cst_lt (bitpos, unfillpos))
7879                 set_nonincremental_init (braced_init_obstack);
7880             }
7881         }
7882
7883       add_pending_init (field, value, origtype, implicit,
7884                         braced_init_obstack);
7885       return;
7886     }
7887   else if (TREE_CODE (constructor_type) == UNION_TYPE
7888            && !VEC_empty (constructor_elt, constructor_elements))
7889     {
7890       if (!implicit)
7891         {
7892           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7893                                            constructor_elements)->value))
7894             warning_init (0,
7895                           "initialized field with side-effects overwritten");
7896           else if (warn_override_init)
7897             warning_init (OPT_Woverride_init, "initialized field overwritten");
7898         }
7899
7900       /* We can have just one union field set.  */
7901       constructor_elements = 0;
7902     }
7903
7904   /* Otherwise, output this element either to
7905      constructor_elements or to the assembler file.  */
7906
7907   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7908   celt->index = field;
7909   celt->value = value;
7910
7911   /* Advance the variable that indicates sequential elements output.  */
7912   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7913     constructor_unfilled_index
7914       = size_binop_loc (input_location, PLUS_EXPR, constructor_unfilled_index,
7915                         bitsize_one_node);
7916   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7917     {
7918       constructor_unfilled_fields
7919         = DECL_CHAIN (constructor_unfilled_fields);
7920
7921       /* Skip any nameless bit fields.  */
7922       while (constructor_unfilled_fields != 0
7923              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7924              && DECL_NAME (constructor_unfilled_fields) == 0)
7925         constructor_unfilled_fields =
7926           DECL_CHAIN (constructor_unfilled_fields);
7927     }
7928   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7929     constructor_unfilled_fields = 0;
7930
7931   /* Now output any pending elements which have become next.  */
7932   if (pending)
7933     output_pending_init_elements (0, braced_init_obstack);
7934 }
7935
7936 /* Output any pending elements which have become next.
7937    As we output elements, constructor_unfilled_{fields,index}
7938    advances, which may cause other elements to become next;
7939    if so, they too are output.
7940
7941    If ALL is 0, we return when there are
7942    no more pending elements to output now.
7943
7944    If ALL is 1, we output space as necessary so that
7945    we can output all the pending elements.  */
7946 static void
7947 output_pending_init_elements (int all, struct obstack * braced_init_obstack)
7948 {
7949   struct init_node *elt = constructor_pending_elts;
7950   tree next;
7951
7952  retry:
7953
7954   /* Look through the whole pending tree.
7955      If we find an element that should be output now,
7956      output it.  Otherwise, set NEXT to the element
7957      that comes first among those still pending.  */
7958
7959   next = 0;
7960   while (elt)
7961     {
7962       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7963         {
7964           if (tree_int_cst_equal (elt->purpose,
7965                                   constructor_unfilled_index))
7966             output_init_element (elt->value, elt->origtype, true,
7967                                  TREE_TYPE (constructor_type),
7968                                  constructor_unfilled_index, 0, false,
7969                                  braced_init_obstack);
7970           else if (tree_int_cst_lt (constructor_unfilled_index,
7971                                     elt->purpose))
7972             {
7973               /* Advance to the next smaller node.  */
7974               if (elt->left)
7975                 elt = elt->left;
7976               else
7977                 {
7978                   /* We have reached the smallest node bigger than the
7979                      current unfilled index.  Fill the space first.  */
7980                   next = elt->purpose;
7981                   break;
7982                 }
7983             }
7984           else
7985             {
7986               /* Advance to the next bigger node.  */
7987               if (elt->right)
7988                 elt = elt->right;
7989               else
7990                 {
7991                   /* We have reached the biggest node in a subtree.  Find
7992                      the parent of it, which is the next bigger node.  */
7993                   while (elt->parent && elt->parent->right == elt)
7994                     elt = elt->parent;
7995                   elt = elt->parent;
7996                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7997                                               elt->purpose))
7998                     {
7999                       next = elt->purpose;
8000                       break;
8001                     }
8002                 }
8003             }
8004         }
8005       else if (TREE_CODE (constructor_type) == RECORD_TYPE
8006                || TREE_CODE (constructor_type) == UNION_TYPE)
8007         {
8008           tree ctor_unfilled_bitpos, elt_bitpos;
8009
8010           /* If the current record is complete we are done.  */
8011           if (constructor_unfilled_fields == 0)
8012             break;
8013
8014           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
8015           elt_bitpos = bit_position (elt->purpose);
8016           /* We can't compare fields here because there might be empty
8017              fields in between.  */
8018           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
8019             {
8020               constructor_unfilled_fields = elt->purpose;
8021               output_init_element (elt->value, elt->origtype, true,
8022                                    TREE_TYPE (elt->purpose),
8023                                    elt->purpose, 0, false,
8024                                    braced_init_obstack);
8025             }
8026           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
8027             {
8028               /* Advance to the next smaller node.  */
8029               if (elt->left)
8030                 elt = elt->left;
8031               else
8032                 {
8033                   /* We have reached the smallest node bigger than the
8034                      current unfilled field.  Fill the space first.  */
8035                   next = elt->purpose;
8036                   break;
8037                 }
8038             }
8039           else
8040             {
8041               /* Advance to the next bigger node.  */
8042               if (elt->right)
8043                 elt = elt->right;
8044               else
8045                 {
8046                   /* We have reached the biggest node in a subtree.  Find
8047                      the parent of it, which is the next bigger node.  */
8048                   while (elt->parent && elt->parent->right == elt)
8049                     elt = elt->parent;
8050                   elt = elt->parent;
8051                   if (elt
8052                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
8053                                            bit_position (elt->purpose))))
8054                     {
8055                       next = elt->purpose;
8056                       break;
8057                     }
8058                 }
8059             }
8060         }
8061     }
8062
8063   /* Ordinarily return, but not if we want to output all
8064      and there are elements left.  */
8065   if (!(all && next != 0))
8066     return;
8067
8068   /* If it's not incremental, just skip over the gap, so that after
8069      jumping to retry we will output the next successive element.  */
8070   if (TREE_CODE (constructor_type) == RECORD_TYPE
8071       || TREE_CODE (constructor_type) == UNION_TYPE)
8072     constructor_unfilled_fields = next;
8073   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
8074     constructor_unfilled_index = next;
8075
8076   /* ELT now points to the node in the pending tree with the next
8077      initializer to output.  */
8078   goto retry;
8079 }
8080 \f
8081 /* Add one non-braced element to the current constructor level.
8082    This adjusts the current position within the constructor's type.
8083    This may also start or terminate implicit levels
8084    to handle a partly-braced initializer.
8085
8086    Once this has found the correct level for the new element,
8087    it calls output_init_element.
8088
8089    IMPLICIT is true if value comes from pop_init_level (1),
8090    the new initializer has been merged with the existing one
8091    and thus no warnings should be emitted about overriding an
8092    existing initializer.  */
8093
8094 void
8095 process_init_element (struct c_expr value, bool implicit,
8096                       struct obstack * braced_init_obstack)
8097 {
8098   tree orig_value = value.value;
8099   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
8100   bool strict_string = value.original_code == STRING_CST;
8101
8102   designator_depth = 0;
8103   designator_erroneous = 0;
8104
8105   /* Handle superfluous braces around string cst as in
8106      char x[] = {"foo"}; */
8107   if (string_flag
8108       && constructor_type
8109       && TREE_CODE (constructor_type) == ARRAY_TYPE
8110       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
8111       && integer_zerop (constructor_unfilled_index))
8112     {
8113       if (constructor_stack->replacement_value.value)
8114         error_init ("excess elements in char array initializer");
8115       constructor_stack->replacement_value = value;
8116       return;
8117     }
8118
8119   if (constructor_stack->replacement_value.value != 0)
8120     {
8121       error_init ("excess elements in struct initializer");
8122       return;
8123     }
8124
8125   /* Ignore elements of a brace group if it is entirely superfluous
8126      and has already been diagnosed.  */
8127   if (constructor_type == 0)
8128     return;
8129
8130   /* If we've exhausted any levels that didn't have braces,
8131      pop them now.  */
8132   while (constructor_stack->implicit)
8133     {
8134       if ((TREE_CODE (constructor_type) == RECORD_TYPE
8135            || TREE_CODE (constructor_type) == UNION_TYPE)
8136           && constructor_fields == 0)
8137         process_init_element (pop_init_level (1, braced_init_obstack),
8138                               true, braced_init_obstack);
8139       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
8140                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
8141                && (constructor_max_index == 0
8142                    || tree_int_cst_lt (constructor_max_index,
8143                                        constructor_index)))
8144         process_init_element (pop_init_level (1, braced_init_obstack),
8145                               true, braced_init_obstack);
8146       else
8147         break;
8148     }
8149
8150   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
8151   if (constructor_range_stack)
8152     {
8153       /* If value is a compound literal and we'll be just using its
8154          content, don't put it into a SAVE_EXPR.  */
8155       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
8156           || !require_constant_value
8157           || flag_isoc99)
8158         {
8159           tree semantic_type = NULL_TREE;
8160           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
8161             {
8162               semantic_type = TREE_TYPE (value.value);
8163               value.value = TREE_OPERAND (value.value, 0);
8164             }
8165           value.value = c_save_expr (value.value);
8166           if (semantic_type)
8167             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
8168                                   value.value);
8169         }
8170     }
8171
8172   while (1)
8173     {
8174       if (TREE_CODE (constructor_type) == RECORD_TYPE)
8175         {
8176           tree fieldtype;
8177           enum tree_code fieldcode;
8178
8179           if (constructor_fields == 0)
8180             {
8181               pedwarn_init (input_location, 0,
8182                             "excess elements in struct initializer");
8183               break;
8184             }
8185
8186           fieldtype = TREE_TYPE (constructor_fields);
8187           if (fieldtype != error_mark_node)
8188             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
8189           fieldcode = TREE_CODE (fieldtype);
8190
8191           /* Error for non-static initialization of a flexible array member.  */
8192           if (fieldcode == ARRAY_TYPE
8193               && !require_constant_value
8194               && TYPE_SIZE (fieldtype) == NULL_TREE
8195               && DECL_CHAIN (constructor_fields) == NULL_TREE)
8196             {
8197               error_init ("non-static initialization of a flexible array member");
8198               break;
8199             }
8200
8201           /* Accept a string constant to initialize a subarray.  */
8202           if (value.value != 0
8203               && fieldcode == ARRAY_TYPE
8204               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
8205               && string_flag)
8206             value.value = orig_value;
8207           /* Otherwise, if we have come to a subaggregate,
8208              and we don't have an element of its type, push into it.  */
8209           else if (value.value != 0
8210                    && value.value != error_mark_node
8211                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
8212                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
8213                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
8214             {
8215               push_init_level (1, braced_init_obstack);
8216               continue;
8217             }
8218
8219           if (value.value)
8220             {
8221               push_member_name (constructor_fields);
8222               output_init_element (value.value, value.original_type,
8223                                    strict_string, fieldtype,
8224                                    constructor_fields, 1, implicit,
8225                                    braced_init_obstack);
8226               RESTORE_SPELLING_DEPTH (constructor_depth);
8227             }
8228           else
8229             /* Do the bookkeeping for an element that was
8230                directly output as a constructor.  */
8231             {
8232               /* For a record, keep track of end position of last field.  */
8233               if (DECL_SIZE (constructor_fields))
8234                 constructor_bit_index
8235                   = size_binop_loc (input_location, PLUS_EXPR,
8236                                     bit_position (constructor_fields),
8237                                     DECL_SIZE (constructor_fields));
8238
8239               /* If the current field was the first one not yet written out,
8240                  it isn't now, so update.  */
8241               if (constructor_unfilled_fields == constructor_fields)
8242                 {
8243                   constructor_unfilled_fields = DECL_CHAIN (constructor_fields);
8244                   /* Skip any nameless bit fields.  */
8245                   while (constructor_unfilled_fields != 0
8246                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
8247                          && DECL_NAME (constructor_unfilled_fields) == 0)
8248                     constructor_unfilled_fields =
8249                       DECL_CHAIN (constructor_unfilled_fields);
8250                 }
8251             }
8252
8253           constructor_fields = DECL_CHAIN (constructor_fields);
8254           /* Skip any nameless bit fields at the beginning.  */
8255           while (constructor_fields != 0
8256                  && DECL_C_BIT_FIELD (constructor_fields)
8257                  && DECL_NAME (constructor_fields) == 0)
8258             constructor_fields = DECL_CHAIN (constructor_fields);
8259         }
8260       else if (TREE_CODE (constructor_type) == UNION_TYPE)
8261         {
8262           tree fieldtype;
8263           enum tree_code fieldcode;
8264
8265           if (constructor_fields == 0)
8266             {
8267               pedwarn_init (input_location, 0,
8268                             "excess elements in union initializer");
8269               break;
8270             }
8271
8272           fieldtype = TREE_TYPE (constructor_fields);
8273           if (fieldtype != error_mark_node)
8274             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
8275           fieldcode = TREE_CODE (fieldtype);
8276
8277           /* Warn that traditional C rejects initialization of unions.
8278              We skip the warning if the value is zero.  This is done
8279              under the assumption that the zero initializer in user
8280              code appears conditioned on e.g. __STDC__ to avoid
8281              "missing initializer" warnings and relies on default
8282              initialization to zero in the traditional C case.
8283              We also skip the warning if the initializer is designated,
8284              again on the assumption that this must be conditional on
8285              __STDC__ anyway (and we've already complained about the
8286              member-designator already).  */
8287           if (!in_system_header && !constructor_designated
8288               && !(value.value && (integer_zerop (value.value)
8289                                    || real_zerop (value.value))))
8290             warning (OPT_Wtraditional, "traditional C rejects initialization "
8291                      "of unions");
8292
8293           /* Accept a string constant to initialize a subarray.  */
8294           if (value.value != 0
8295               && fieldcode == ARRAY_TYPE
8296               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
8297               && string_flag)
8298             value.value = orig_value;
8299           /* Otherwise, if we have come to a subaggregate,
8300              and we don't have an element of its type, push into it.  */
8301           else if (value.value != 0
8302                    && value.value != error_mark_node
8303                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
8304                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
8305                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
8306             {
8307               push_init_level (1, braced_init_obstack);
8308               continue;
8309             }
8310
8311           if (value.value)
8312             {
8313               push_member_name (constructor_fields);
8314               output_init_element (value.value, value.original_type,
8315                                    strict_string, fieldtype,
8316                                    constructor_fields, 1, implicit,
8317                                    braced_init_obstack);
8318               RESTORE_SPELLING_DEPTH (constructor_depth);
8319             }
8320           else
8321             /* Do the bookkeeping for an element that was
8322                directly output as a constructor.  */
8323             {
8324               constructor_bit_index = DECL_SIZE (constructor_fields);
8325               constructor_unfilled_fields = DECL_CHAIN (constructor_fields);
8326             }
8327
8328           constructor_fields = 0;
8329         }
8330       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
8331         {
8332           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
8333           enum tree_code eltcode = TREE_CODE (elttype);
8334
8335           /* Accept a string constant to initialize a subarray.  */
8336           if (value.value != 0
8337               && eltcode == ARRAY_TYPE
8338               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
8339               && string_flag)
8340             value.value = orig_value;
8341           /* Otherwise, if we have come to a subaggregate,
8342              and we don't have an element of its type, push into it.  */
8343           else if (value.value != 0
8344                    && value.value != error_mark_node
8345                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
8346                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
8347                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
8348             {
8349               push_init_level (1, braced_init_obstack);
8350               continue;
8351             }
8352
8353           if (constructor_max_index != 0
8354               && (tree_int_cst_lt (constructor_max_index, constructor_index)
8355                   || integer_all_onesp (constructor_max_index)))
8356             {
8357               pedwarn_init (input_location, 0,
8358                             "excess elements in array initializer");
8359               break;
8360             }
8361
8362           /* Now output the actual element.  */
8363           if (value.value)
8364             {
8365               push_array_bounds (tree_low_cst (constructor_index, 1));
8366               output_init_element (value.value, value.original_type,
8367                                    strict_string, elttype,
8368                                    constructor_index, 1, implicit,
8369                                    braced_init_obstack);
8370               RESTORE_SPELLING_DEPTH (constructor_depth);
8371             }
8372
8373           constructor_index
8374             = size_binop_loc (input_location, PLUS_EXPR,
8375                               constructor_index, bitsize_one_node);
8376
8377           if (!value.value)
8378             /* If we are doing the bookkeeping for an element that was
8379                directly output as a constructor, we must update
8380                constructor_unfilled_index.  */
8381             constructor_unfilled_index = constructor_index;
8382         }
8383       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
8384         {
8385           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
8386
8387          /* Do a basic check of initializer size.  Note that vectors
8388             always have a fixed size derived from their type.  */
8389           if (tree_int_cst_lt (constructor_max_index, constructor_index))
8390             {
8391               pedwarn_init (input_location, 0,
8392                             "excess elements in vector initializer");
8393               break;
8394             }
8395
8396           /* Now output the actual element.  */
8397           if (value.value)
8398             {
8399               if (TREE_CODE (value.value) == VECTOR_CST)
8400                 elttype = TYPE_MAIN_VARIANT (constructor_type);
8401               output_init_element (value.value, value.original_type,
8402                                    strict_string, elttype,
8403                                    constructor_index, 1, implicit,
8404                                    braced_init_obstack);
8405             }
8406
8407           constructor_index
8408             = size_binop_loc (input_location,
8409                               PLUS_EXPR, constructor_index, bitsize_one_node);
8410
8411           if (!value.value)
8412             /* If we are doing the bookkeeping for an element that was
8413                directly output as a constructor, we must update
8414                constructor_unfilled_index.  */
8415             constructor_unfilled_index = constructor_index;
8416         }
8417
8418       /* Handle the sole element allowed in a braced initializer
8419          for a scalar variable.  */
8420       else if (constructor_type != error_mark_node
8421                && constructor_fields == 0)
8422         {
8423           pedwarn_init (input_location, 0,
8424                         "excess elements in scalar initializer");
8425           break;
8426         }
8427       else
8428         {
8429           if (value.value)
8430             output_init_element (value.value, value.original_type,
8431                                  strict_string, constructor_type,
8432                                  NULL_TREE, 1, implicit,
8433                                  braced_init_obstack);
8434           constructor_fields = 0;
8435         }
8436
8437       /* Handle range initializers either at this level or anywhere higher
8438          in the designator stack.  */
8439       if (constructor_range_stack)
8440         {
8441           struct constructor_range_stack *p, *range_stack;
8442           int finish = 0;
8443
8444           range_stack = constructor_range_stack;
8445           constructor_range_stack = 0;
8446           while (constructor_stack != range_stack->stack)
8447             {
8448               gcc_assert (constructor_stack->implicit);
8449               process_init_element (pop_init_level (1,
8450                                                     braced_init_obstack),
8451                                     true, braced_init_obstack);
8452             }
8453           for (p = range_stack;
8454                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
8455                p = p->prev)
8456             {
8457               gcc_assert (constructor_stack->implicit);
8458               process_init_element (pop_init_level (1, braced_init_obstack),
8459                                     true, braced_init_obstack);
8460             }
8461
8462           p->index = size_binop_loc (input_location,
8463                                      PLUS_EXPR, p->index, bitsize_one_node);
8464           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
8465             finish = 1;
8466
8467           while (1)
8468             {
8469               constructor_index = p->index;
8470               constructor_fields = p->fields;
8471               if (finish && p->range_end && p->index == p->range_start)
8472                 {
8473                   finish = 0;
8474                   p->prev = 0;
8475                 }
8476               p = p->next;
8477               if (!p)
8478                 break;
8479               push_init_level (2, braced_init_obstack);
8480               p->stack = constructor_stack;
8481               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
8482                 p->index = p->range_start;
8483             }
8484
8485           if (!finish)
8486             constructor_range_stack = range_stack;
8487           continue;
8488         }
8489
8490       break;
8491     }
8492
8493   constructor_range_stack = 0;
8494 }
8495 \f
8496 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
8497    (guaranteed to be 'volatile' or null) and ARGS (represented using
8498    an ASM_EXPR node).  */
8499 tree
8500 build_asm_stmt (tree cv_qualifier, tree args)
8501 {
8502   if (!ASM_VOLATILE_P (args) && cv_qualifier)
8503     ASM_VOLATILE_P (args) = 1;
8504   return add_stmt (args);
8505 }
8506
8507 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
8508    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
8509    SIMPLE indicates whether there was anything at all after the
8510    string in the asm expression -- asm("blah") and asm("blah" : )
8511    are subtly different.  We use a ASM_EXPR node to represent this.  */
8512 tree
8513 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
8514                 tree clobbers, tree labels, bool simple)
8515 {
8516   tree tail;
8517   tree args;
8518   int i;
8519   const char *constraint;
8520   const char **oconstraints;
8521   bool allows_mem, allows_reg, is_inout;
8522   int ninputs, noutputs;
8523
8524   ninputs = list_length (inputs);
8525   noutputs = list_length (outputs);
8526   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
8527
8528   string = resolve_asm_operand_names (string, outputs, inputs, labels);
8529
8530   /* Remove output conversions that change the type but not the mode.  */
8531   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
8532     {
8533       tree output = TREE_VALUE (tail);
8534
8535       /* ??? Really, this should not be here.  Users should be using a
8536          proper lvalue, dammit.  But there's a long history of using casts
8537          in the output operands.  In cases like longlong.h, this becomes a
8538          primitive form of typechecking -- if the cast can be removed, then
8539          the output operand had a type of the proper width; otherwise we'll
8540          get an error.  Gross, but ...  */
8541       STRIP_NOPS (output);
8542
8543       if (!lvalue_or_else (output, lv_asm))
8544         output = error_mark_node;
8545
8546       if (output != error_mark_node
8547           && (TREE_READONLY (output)
8548               || TYPE_READONLY (TREE_TYPE (output))
8549               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
8550                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
8551                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
8552         readonly_error (output, lv_asm);
8553
8554       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8555       oconstraints[i] = constraint;
8556
8557       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
8558                                    &allows_mem, &allows_reg, &is_inout))
8559         {
8560           /* If the operand is going to end up in memory,
8561              mark it addressable.  */
8562           if (!allows_reg && !c_mark_addressable (output))
8563             output = error_mark_node;
8564         }
8565       else
8566         output = error_mark_node;
8567
8568       TREE_VALUE (tail) = output;
8569     }
8570
8571   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
8572     {
8573       tree input;
8574
8575       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8576       input = TREE_VALUE (tail);
8577
8578       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
8579                                   oconstraints, &allows_mem, &allows_reg))
8580         {
8581           /* If the operand is going to end up in memory,
8582              mark it addressable.  */
8583           if (!allows_reg && allows_mem)
8584             {
8585               /* Strip the nops as we allow this case.  FIXME, this really
8586                  should be rejected or made deprecated.  */
8587               STRIP_NOPS (input);
8588               if (!c_mark_addressable (input))
8589                 input = error_mark_node;
8590           }
8591         }
8592       else
8593         input = error_mark_node;
8594
8595       TREE_VALUE (tail) = input;
8596     }
8597
8598   /* ASMs with labels cannot have outputs.  This should have been
8599      enforced by the parser.  */
8600   gcc_assert (outputs == NULL || labels == NULL);
8601
8602   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers, labels);
8603
8604   /* asm statements without outputs, including simple ones, are treated
8605      as volatile.  */
8606   ASM_INPUT_P (args) = simple;
8607   ASM_VOLATILE_P (args) = (noutputs == 0);
8608
8609   return args;
8610 }
8611 \f
8612 /* Generate a goto statement to LABEL.  LOC is the location of the
8613    GOTO.  */
8614
8615 tree
8616 c_finish_goto_label (location_t loc, tree label)
8617 {
8618   tree decl = lookup_label_for_goto (loc, label);
8619   if (!decl)
8620     return NULL_TREE;
8621   TREE_USED (decl) = 1;
8622   {
8623     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8624     SET_EXPR_LOCATION (t, loc);
8625     return add_stmt (t);
8626   }
8627 }
8628
8629 /* Generate a computed goto statement to EXPR.  LOC is the location of
8630    the GOTO.  */
8631
8632 tree
8633 c_finish_goto_ptr (location_t loc, tree expr)
8634 {
8635   tree t;
8636   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8637   expr = c_fully_fold (expr, false, NULL);
8638   expr = convert (ptr_type_node, expr);
8639   t = build1 (GOTO_EXPR, void_type_node, expr);
8640   SET_EXPR_LOCATION (t, loc);
8641   return add_stmt (t);
8642 }
8643
8644 /* Generate a C `return' statement.  RETVAL is the expression for what
8645    to return, or a null pointer for `return;' with no value.  LOC is
8646    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8647    is the original type of RETVAL.  */
8648
8649 tree
8650 c_finish_return (location_t loc, tree retval, tree origtype)
8651 {
8652   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8653   bool no_warning = false;
8654   bool npc = false;
8655
8656   if (TREE_THIS_VOLATILE (current_function_decl))
8657     warning_at (loc, 0,
8658                 "function declared %<noreturn%> has a %<return%> statement");
8659
8660   if (retval)
8661     {
8662       tree semantic_type = NULL_TREE;
8663       npc = null_pointer_constant_p (retval);
8664       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8665         {
8666           semantic_type = TREE_TYPE (retval);
8667           retval = TREE_OPERAND (retval, 0);
8668         }
8669       retval = c_fully_fold (retval, false, NULL);
8670       if (semantic_type)
8671         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8672     }
8673
8674   if (!retval)
8675     {
8676       current_function_returns_null = 1;
8677       if ((warn_return_type || flag_isoc99)
8678           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8679         {
8680           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8681                        "%<return%> with no value, in "
8682                        "function returning non-void");
8683           no_warning = true;
8684         }
8685     }
8686   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8687     {
8688       current_function_returns_null = 1;
8689       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8690         pedwarn (loc, 0,
8691                  "%<return%> with a value, in function returning void");
8692       else
8693         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8694                  "%<return%> with expression, in function returning void");
8695     }
8696   else
8697     {
8698       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8699                                        ic_return,
8700                                        npc, NULL_TREE, NULL_TREE, 0);
8701       tree res = DECL_RESULT (current_function_decl);
8702       tree inner;
8703
8704       current_function_returns_value = 1;
8705       if (t == error_mark_node)
8706         return NULL_TREE;
8707
8708       inner = t = convert (TREE_TYPE (res), t);
8709
8710       /* Strip any conversions, additions, and subtractions, and see if
8711          we are returning the address of a local variable.  Warn if so.  */
8712       while (1)
8713         {
8714           switch (TREE_CODE (inner))
8715             {
8716             CASE_CONVERT:
8717             case NON_LVALUE_EXPR:
8718             case PLUS_EXPR:
8719             case POINTER_PLUS_EXPR:
8720               inner = TREE_OPERAND (inner, 0);
8721               continue;
8722
8723             case MINUS_EXPR:
8724               /* If the second operand of the MINUS_EXPR has a pointer
8725                  type (or is converted from it), this may be valid, so
8726                  don't give a warning.  */
8727               {
8728                 tree op1 = TREE_OPERAND (inner, 1);
8729
8730                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8731                        && (CONVERT_EXPR_P (op1)
8732                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8733                   op1 = TREE_OPERAND (op1, 0);
8734
8735                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8736                   break;
8737
8738                 inner = TREE_OPERAND (inner, 0);
8739                 continue;
8740               }
8741
8742             case ADDR_EXPR:
8743               inner = TREE_OPERAND (inner, 0);
8744
8745               while (REFERENCE_CLASS_P (inner)
8746                      && TREE_CODE (inner) != INDIRECT_REF)
8747                 inner = TREE_OPERAND (inner, 0);
8748
8749               if (DECL_P (inner)
8750                   && !DECL_EXTERNAL (inner)
8751                   && !TREE_STATIC (inner)
8752                   && DECL_CONTEXT (inner) == current_function_decl)
8753                 warning_at (loc,
8754                             0, "function returns address of local variable");
8755               break;
8756
8757             default:
8758               break;
8759             }
8760
8761           break;
8762         }
8763
8764       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8765       SET_EXPR_LOCATION (retval, loc);
8766
8767       if (warn_sequence_point)
8768         verify_sequence_points (retval);
8769     }
8770
8771   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8772   TREE_NO_WARNING (ret_stmt) |= no_warning;
8773   return add_stmt (ret_stmt);
8774 }
8775 \f
8776 struct c_switch {
8777   /* The SWITCH_EXPR being built.  */
8778   tree switch_expr;
8779
8780   /* The original type of the testing expression, i.e. before the
8781      default conversion is applied.  */
8782   tree orig_type;
8783
8784   /* A splay-tree mapping the low element of a case range to the high
8785      element, or NULL_TREE if there is no high element.  Used to
8786      determine whether or not a new case label duplicates an old case
8787      label.  We need a tree, rather than simply a hash table, because
8788      of the GNU case range extension.  */
8789   splay_tree cases;
8790
8791   /* The bindings at the point of the switch.  This is used for
8792      warnings crossing decls when branching to a case label.  */
8793   struct c_spot_bindings *bindings;
8794
8795   /* The next node on the stack.  */
8796   struct c_switch *next;
8797 };
8798
8799 /* A stack of the currently active switch statements.  The innermost
8800    switch statement is on the top of the stack.  There is no need to
8801    mark the stack for garbage collection because it is only active
8802    during the processing of the body of a function, and we never
8803    collect at that point.  */
8804
8805 struct c_switch *c_switch_stack;
8806
8807 /* Start a C switch statement, testing expression EXP.  Return the new
8808    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8809    SWITCH_COND_LOC is the location of the switch's condition.  */
8810
8811 tree
8812 c_start_case (location_t switch_loc,
8813               location_t switch_cond_loc,
8814               tree exp)
8815 {
8816   tree orig_type = error_mark_node;
8817   struct c_switch *cs;
8818
8819   if (exp != error_mark_node)
8820     {
8821       orig_type = TREE_TYPE (exp);
8822
8823       if (!INTEGRAL_TYPE_P (orig_type))
8824         {
8825           if (orig_type != error_mark_node)
8826             {
8827               error_at (switch_cond_loc, "switch quantity not an integer");
8828               orig_type = error_mark_node;
8829             }
8830           exp = integer_zero_node;
8831         }
8832       else
8833         {
8834           tree type = TYPE_MAIN_VARIANT (orig_type);
8835
8836           if (!in_system_header
8837               && (type == long_integer_type_node
8838                   || type == long_unsigned_type_node))
8839             warning_at (switch_cond_loc,
8840                         OPT_Wtraditional, "%<long%> switch expression not "
8841                         "converted to %<int%> in ISO C");
8842
8843           exp = c_fully_fold (exp, false, NULL);
8844           exp = default_conversion (exp);
8845
8846           if (warn_sequence_point)
8847             verify_sequence_points (exp);
8848         }
8849     }
8850
8851   /* Add this new SWITCH_EXPR to the stack.  */
8852   cs = XNEW (struct c_switch);
8853   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8854   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8855   cs->orig_type = orig_type;
8856   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8857   cs->bindings = c_get_switch_bindings ();
8858   cs->next = c_switch_stack;
8859   c_switch_stack = cs;
8860
8861   return add_stmt (cs->switch_expr);
8862 }
8863
8864 /* Process a case label at location LOC.  */
8865
8866 tree
8867 do_case (location_t loc, tree low_value, tree high_value)
8868 {
8869   tree label = NULL_TREE;
8870
8871   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8872     {
8873       low_value = c_fully_fold (low_value, false, NULL);
8874       if (TREE_CODE (low_value) == INTEGER_CST)
8875         pedwarn (input_location, OPT_pedantic,
8876                  "case label is not an integer constant expression");
8877     }
8878
8879   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8880     {
8881       high_value = c_fully_fold (high_value, false, NULL);
8882       if (TREE_CODE (high_value) == INTEGER_CST)
8883         pedwarn (input_location, OPT_pedantic,
8884                  "case label is not an integer constant expression");
8885     }
8886
8887   if (c_switch_stack == NULL)
8888     {
8889       if (low_value)
8890         error_at (loc, "case label not within a switch statement");
8891       else
8892         error_at (loc, "%<default%> label not within a switch statement");
8893       return NULL_TREE;
8894     }
8895
8896   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8897                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8898                                     loc))
8899     return NULL_TREE;
8900
8901   label = c_add_case_label (loc, c_switch_stack->cases,
8902                             SWITCH_COND (c_switch_stack->switch_expr),
8903                             c_switch_stack->orig_type,
8904                             low_value, high_value);
8905   if (label == error_mark_node)
8906     label = NULL_TREE;
8907   return label;
8908 }
8909
8910 /* Finish the switch statement.  */
8911
8912 void
8913 c_finish_case (tree body)
8914 {
8915   struct c_switch *cs = c_switch_stack;
8916   location_t switch_location;
8917
8918   SWITCH_BODY (cs->switch_expr) = body;
8919
8920   /* Emit warnings as needed.  */
8921   switch_location = EXPR_LOCATION (cs->switch_expr);
8922   c_do_switch_warnings (cs->cases, switch_location,
8923                         TREE_TYPE (cs->switch_expr),
8924                         SWITCH_COND (cs->switch_expr));
8925
8926   /* Pop the stack.  */
8927   c_switch_stack = cs->next;
8928   splay_tree_delete (cs->cases);
8929   c_release_switch_bindings (cs->bindings);
8930   XDELETE (cs);
8931 }
8932 \f
8933 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8934    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8935    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8936    statement, and was not surrounded with parenthesis.  */
8937
8938 void
8939 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8940                   tree else_block, bool nested_if)
8941 {
8942   tree stmt;
8943
8944   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8945   if (warn_parentheses && nested_if && else_block == NULL)
8946     {
8947       tree inner_if = then_block;
8948
8949       /* We know from the grammar productions that there is an IF nested
8950          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8951          it might not be exactly THEN_BLOCK, but should be the last
8952          non-container statement within.  */
8953       while (1)
8954         switch (TREE_CODE (inner_if))
8955           {
8956           case COND_EXPR:
8957             goto found;
8958           case BIND_EXPR:
8959             inner_if = BIND_EXPR_BODY (inner_if);
8960             break;
8961           case STATEMENT_LIST:
8962             inner_if = expr_last (then_block);
8963             break;
8964           case TRY_FINALLY_EXPR:
8965           case TRY_CATCH_EXPR:
8966             inner_if = TREE_OPERAND (inner_if, 0);
8967             break;
8968           default:
8969             gcc_unreachable ();
8970           }
8971     found:
8972
8973       if (COND_EXPR_ELSE (inner_if))
8974          warning_at (if_locus, OPT_Wparentheses,
8975                      "suggest explicit braces to avoid ambiguous %<else%>");
8976     }
8977
8978   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8979   SET_EXPR_LOCATION (stmt, if_locus);
8980   add_stmt (stmt);
8981 }
8982
8983 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8984    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8985    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8986    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8987    the continue label.  Everything is allowed to be NULL.  */
8988
8989 void
8990 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8991                tree blab, tree clab, bool cond_is_first)
8992 {
8993   tree entry = NULL, exit = NULL, t;
8994
8995   /* If the condition is zero don't generate a loop construct.  */
8996   if (cond && integer_zerop (cond))
8997     {
8998       if (cond_is_first)
8999         {
9000           t = build_and_jump (&blab);
9001           SET_EXPR_LOCATION (t, start_locus);
9002           add_stmt (t);
9003         }
9004     }
9005   else
9006     {
9007       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
9008
9009       /* If we have an exit condition, then we build an IF with gotos either
9010          out of the loop, or to the top of it.  If there's no exit condition,
9011          then we just build a jump back to the top.  */
9012       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
9013
9014       if (cond && !integer_nonzerop (cond))
9015         {
9016           /* Canonicalize the loop condition to the end.  This means
9017              generating a branch to the loop condition.  Reuse the
9018              continue label, if possible.  */
9019           if (cond_is_first)
9020             {
9021               if (incr || !clab)
9022                 {
9023                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
9024                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
9025                 }
9026               else
9027                 t = build1 (GOTO_EXPR, void_type_node, clab);
9028               SET_EXPR_LOCATION (t, start_locus);
9029               add_stmt (t);
9030             }
9031
9032           t = build_and_jump (&blab);
9033           if (cond_is_first)
9034             exit = fold_build3_loc (start_locus,
9035                                 COND_EXPR, void_type_node, cond, exit, t);
9036           else
9037             exit = fold_build3_loc (input_location,
9038                                 COND_EXPR, void_type_node, cond, exit, t);
9039         }
9040
9041       add_stmt (top);
9042     }
9043
9044   if (body)
9045     add_stmt (body);
9046   if (clab)
9047     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
9048   if (incr)
9049     add_stmt (incr);
9050   if (entry)
9051     add_stmt (entry);
9052   if (exit)
9053     add_stmt (exit);
9054   if (blab)
9055     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
9056 }
9057
9058 tree
9059 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
9060 {
9061   bool skip;
9062   tree label = *label_p;
9063
9064   /* In switch statements break is sometimes stylistically used after
9065      a return statement.  This can lead to spurious warnings about
9066      control reaching the end of a non-void function when it is
9067      inlined.  Note that we are calling block_may_fallthru with
9068      language specific tree nodes; this works because
9069      block_may_fallthru returns true when given something it does not
9070      understand.  */
9071   skip = !block_may_fallthru (cur_stmt_list);
9072
9073   if (!label)
9074     {
9075       if (!skip)
9076         *label_p = label = create_artificial_label (loc);
9077     }
9078   else if (TREE_CODE (label) == LABEL_DECL)
9079     ;
9080   else switch (TREE_INT_CST_LOW (label))
9081     {
9082     case 0:
9083       if (is_break)
9084         error_at (loc, "break statement not within loop or switch");
9085       else
9086         error_at (loc, "continue statement not within a loop");
9087       return NULL_TREE;
9088
9089     case 1:
9090       gcc_assert (is_break);
9091       error_at (loc, "break statement used with OpenMP for loop");
9092       return NULL_TREE;
9093
9094     default:
9095       gcc_unreachable ();
9096     }
9097
9098   if (skip)
9099     return NULL_TREE;
9100
9101   if (!is_break)
9102     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
9103
9104   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
9105 }
9106
9107 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
9108
9109 static void
9110 emit_side_effect_warnings (location_t loc, tree expr)
9111 {
9112   if (expr == error_mark_node)
9113     ;
9114   else if (!TREE_SIDE_EFFECTS (expr))
9115     {
9116       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
9117         warning_at (loc, OPT_Wunused_value, "statement with no effect");
9118     }
9119   else
9120     warn_if_unused_value (expr, loc);
9121 }
9122
9123 /* Process an expression as if it were a complete statement.  Emit
9124    diagnostics, but do not call ADD_STMT.  LOC is the location of the
9125    statement.  */
9126
9127 tree
9128 c_process_expr_stmt (location_t loc, tree expr)
9129 {
9130   tree exprv;
9131
9132   if (!expr)
9133     return NULL_TREE;
9134
9135   expr = c_fully_fold (expr, false, NULL);
9136
9137   if (warn_sequence_point)
9138     verify_sequence_points (expr);
9139
9140   if (TREE_TYPE (expr) != error_mark_node
9141       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
9142       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
9143     error_at (loc, "expression statement has incomplete type");
9144
9145   /* If we're not processing a statement expression, warn about unused values.
9146      Warnings for statement expressions will be emitted later, once we figure
9147      out which is the result.  */
9148   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
9149       && warn_unused_value)
9150     emit_side_effect_warnings (loc, expr);
9151
9152   exprv = expr;
9153   while (TREE_CODE (exprv) == COMPOUND_EXPR)
9154     exprv = TREE_OPERAND (exprv, 1);
9155   if (DECL_P (exprv) || handled_component_p (exprv))
9156     mark_exp_read (exprv);
9157
9158   /* If the expression is not of a type to which we cannot assign a line
9159      number, wrap the thing in a no-op NOP_EXPR.  */
9160   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
9161     {
9162       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9163       SET_EXPR_LOCATION (expr, loc);
9164     }
9165
9166   return expr;
9167 }
9168
9169 /* Emit an expression as a statement.  LOC is the location of the
9170    expression.  */
9171
9172 tree
9173 c_finish_expr_stmt (location_t loc, tree expr)
9174 {
9175   if (expr)
9176     return add_stmt (c_process_expr_stmt (loc, expr));
9177   else
9178     return NULL;
9179 }
9180
9181 /* Do the opposite and emit a statement as an expression.  To begin,
9182    create a new binding level and return it.  */
9183
9184 tree
9185 c_begin_stmt_expr (void)
9186 {
9187   tree ret;
9188
9189   /* We must force a BLOCK for this level so that, if it is not expanded
9190      later, there is a way to turn off the entire subtree of blocks that
9191      are contained in it.  */
9192   keep_next_level ();
9193   ret = c_begin_compound_stmt (true);
9194
9195   c_bindings_start_stmt_expr (c_switch_stack == NULL
9196                               ? NULL
9197                               : c_switch_stack->bindings);
9198
9199   /* Mark the current statement list as belonging to a statement list.  */
9200   STATEMENT_LIST_STMT_EXPR (ret) = 1;
9201
9202   return ret;
9203 }
9204
9205 /* LOC is the location of the compound statement to which this body
9206    belongs.  */
9207
9208 tree
9209 c_finish_stmt_expr (location_t loc, tree body)
9210 {
9211   tree last, type, tmp, val;
9212   tree *last_p;
9213
9214   body = c_end_compound_stmt (loc, body, true);
9215
9216   c_bindings_end_stmt_expr (c_switch_stack == NULL
9217                             ? NULL
9218                             : c_switch_stack->bindings);
9219
9220   /* Locate the last statement in BODY.  See c_end_compound_stmt
9221      about always returning a BIND_EXPR.  */
9222   last_p = &BIND_EXPR_BODY (body);
9223   last = BIND_EXPR_BODY (body);
9224
9225  continue_searching:
9226   if (TREE_CODE (last) == STATEMENT_LIST)
9227     {
9228       tree_stmt_iterator i;
9229
9230       /* This can happen with degenerate cases like ({ }).  No value.  */
9231       if (!TREE_SIDE_EFFECTS (last))
9232         return body;
9233
9234       /* If we're supposed to generate side effects warnings, process
9235          all of the statements except the last.  */
9236       if (warn_unused_value)
9237         {
9238           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
9239             {
9240               location_t tloc;
9241               tree t = tsi_stmt (i);
9242
9243               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
9244               emit_side_effect_warnings (tloc, t);
9245             }
9246         }
9247       else
9248         i = tsi_last (last);
9249       last_p = tsi_stmt_ptr (i);
9250       last = *last_p;
9251     }
9252
9253   /* If the end of the list is exception related, then the list was split
9254      by a call to push_cleanup.  Continue searching.  */
9255   if (TREE_CODE (last) == TRY_FINALLY_EXPR
9256       || TREE_CODE (last) == TRY_CATCH_EXPR)
9257     {
9258       last_p = &TREE_OPERAND (last, 0);
9259       last = *last_p;
9260       goto continue_searching;
9261     }
9262
9263   if (last == error_mark_node)
9264     return last;
9265
9266   /* In the case that the BIND_EXPR is not necessary, return the
9267      expression out from inside it.  */
9268   if (last == BIND_EXPR_BODY (body)
9269       && BIND_EXPR_VARS (body) == NULL)
9270     {
9271       /* Even if this looks constant, do not allow it in a constant
9272          expression.  */
9273       last = c_wrap_maybe_const (last, true);
9274       /* Do not warn if the return value of a statement expression is
9275          unused.  */
9276       TREE_NO_WARNING (last) = 1;
9277       return last;
9278     }
9279
9280   /* Extract the type of said expression.  */
9281   type = TREE_TYPE (last);
9282
9283   /* If we're not returning a value at all, then the BIND_EXPR that
9284      we already have is a fine expression to return.  */
9285   if (!type || VOID_TYPE_P (type))
9286     return body;
9287
9288   /* Now that we've located the expression containing the value, it seems
9289      silly to make voidify_wrapper_expr repeat the process.  Create a
9290      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
9291   tmp = create_tmp_var_raw (type, NULL);
9292
9293   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
9294      tree_expr_nonnegative_p giving up immediately.  */
9295   val = last;
9296   if (TREE_CODE (val) == NOP_EXPR
9297       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
9298     val = TREE_OPERAND (val, 0);
9299
9300   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
9301   SET_EXPR_LOCATION (*last_p, EXPR_LOCATION (last));
9302
9303   {
9304     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
9305     SET_EXPR_LOCATION (t, loc);
9306     return t;
9307   }
9308 }
9309 \f
9310 /* Begin and end compound statements.  This is as simple as pushing
9311    and popping new statement lists from the tree.  */
9312
9313 tree
9314 c_begin_compound_stmt (bool do_scope)
9315 {
9316   tree stmt = push_stmt_list ();
9317   if (do_scope)
9318     push_scope ();
9319   return stmt;
9320 }
9321
9322 /* End a compound statement.  STMT is the statement.  LOC is the
9323    location of the compound statement-- this is usually the location
9324    of the opening brace.  */
9325
9326 tree
9327 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
9328 {
9329   tree block = NULL;
9330
9331   if (do_scope)
9332     {
9333       if (c_dialect_objc ())
9334         objc_clear_super_receiver ();
9335       block = pop_scope ();
9336     }
9337
9338   stmt = pop_stmt_list (stmt);
9339   stmt = c_build_bind_expr (loc, block, stmt);
9340
9341   /* If this compound statement is nested immediately inside a statement
9342      expression, then force a BIND_EXPR to be created.  Otherwise we'll
9343      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
9344      STATEMENT_LISTs merge, and thus we can lose track of what statement
9345      was really last.  */
9346   if (cur_stmt_list
9347       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
9348       && TREE_CODE (stmt) != BIND_EXPR)
9349     {
9350       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
9351       TREE_SIDE_EFFECTS (stmt) = 1;
9352       SET_EXPR_LOCATION (stmt, loc);
9353     }
9354
9355   return stmt;
9356 }
9357
9358 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
9359    when the current scope is exited.  EH_ONLY is true when this is not
9360    meant to apply to normal control flow transfer.  */
9361
9362 void
9363 push_cleanup (tree decl, tree cleanup, bool eh_only)
9364 {
9365   enum tree_code code;
9366   tree stmt, list;
9367   bool stmt_expr;
9368
9369   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
9370   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
9371   add_stmt (stmt);
9372   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
9373   list = push_stmt_list ();
9374   TREE_OPERAND (stmt, 0) = list;
9375   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
9376 }
9377 \f
9378 /* Build a binary-operation expression without default conversions.
9379    CODE is the kind of expression to build.
9380    LOCATION is the operator's location.
9381    This function differs from `build' in several ways:
9382    the data type of the result is computed and recorded in it,
9383    warnings are generated if arg data types are invalid,
9384    special handling for addition and subtraction of pointers is known,
9385    and some optimization is done (operations on narrow ints
9386    are done in the narrower type when that gives the same result).
9387    Constant folding is also done before the result is returned.
9388
9389    Note that the operands will never have enumeral types, or function
9390    or array types, because either they will have the default conversions
9391    performed or they have both just been converted to some other type in which
9392    the arithmetic is to be done.  */
9393
9394 tree
9395 build_binary_op (location_t location, enum tree_code code,
9396                  tree orig_op0, tree orig_op1, int convert_p)
9397 {
9398   tree type0, type1, orig_type0, orig_type1;
9399   tree eptype;
9400   enum tree_code code0, code1;
9401   tree op0, op1;
9402   tree ret = error_mark_node;
9403   const char *invalid_op_diag;
9404   bool op0_int_operands, op1_int_operands;
9405   bool int_const, int_const_or_overflow, int_operands;
9406
9407   /* Expression code to give to the expression when it is built.
9408      Normally this is CODE, which is what the caller asked for,
9409      but in some special cases we change it.  */
9410   enum tree_code resultcode = code;
9411
9412   /* Data type in which the computation is to be performed.
9413      In the simplest cases this is the common type of the arguments.  */
9414   tree result_type = NULL;
9415
9416   /* When the computation is in excess precision, the type of the
9417      final EXCESS_PRECISION_EXPR.  */
9418   tree semantic_result_type = NULL;
9419
9420   /* Nonzero means operands have already been type-converted
9421      in whatever way is necessary.
9422      Zero means they need to be converted to RESULT_TYPE.  */
9423   int converted = 0;
9424
9425   /* Nonzero means create the expression with this type, rather than
9426      RESULT_TYPE.  */
9427   tree build_type = 0;
9428
9429   /* Nonzero means after finally constructing the expression
9430      convert it to this type.  */
9431   tree final_type = 0;
9432
9433   /* Nonzero if this is an operation like MIN or MAX which can
9434      safely be computed in short if both args are promoted shorts.
9435      Also implies COMMON.
9436      -1 indicates a bitwise operation; this makes a difference
9437      in the exact conditions for when it is safe to do the operation
9438      in a narrower mode.  */
9439   int shorten = 0;
9440
9441   /* Nonzero if this is a comparison operation;
9442      if both args are promoted shorts, compare the original shorts.
9443      Also implies COMMON.  */
9444   int short_compare = 0;
9445
9446   /* Nonzero if this is a right-shift operation, which can be computed on the
9447      original short and then promoted if the operand is a promoted short.  */
9448   int short_shift = 0;
9449
9450   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
9451   int common = 0;
9452
9453   /* True means types are compatible as far as ObjC is concerned.  */
9454   bool objc_ok;
9455
9456   /* True means this is an arithmetic operation that may need excess
9457      precision.  */
9458   bool may_need_excess_precision;
9459
9460   /* True means this is a boolean operation that converts both its
9461      operands to truth-values.  */
9462   bool boolean_op = false;
9463
9464   if (location == UNKNOWN_LOCATION)
9465     location = input_location;
9466
9467   op0 = orig_op0;
9468   op1 = orig_op1;
9469
9470   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
9471   if (op0_int_operands)
9472     op0 = remove_c_maybe_const_expr (op0);
9473   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
9474   if (op1_int_operands)
9475     op1 = remove_c_maybe_const_expr (op1);
9476   int_operands = (op0_int_operands && op1_int_operands);
9477   if (int_operands)
9478     {
9479       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
9480                                && TREE_CODE (orig_op1) == INTEGER_CST);
9481       int_const = (int_const_or_overflow
9482                    && !TREE_OVERFLOW (orig_op0)
9483                    && !TREE_OVERFLOW (orig_op1));
9484     }
9485   else
9486     int_const = int_const_or_overflow = false;
9487
9488   if (convert_p)
9489     {
9490       op0 = default_conversion (op0);
9491       op1 = default_conversion (op1);
9492     }
9493
9494   orig_type0 = type0 = TREE_TYPE (op0);
9495   orig_type1 = type1 = TREE_TYPE (op1);
9496
9497   /* The expression codes of the data types of the arguments tell us
9498      whether the arguments are integers, floating, pointers, etc.  */
9499   code0 = TREE_CODE (type0);
9500   code1 = TREE_CODE (type1);
9501
9502   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
9503   STRIP_TYPE_NOPS (op0);
9504   STRIP_TYPE_NOPS (op1);
9505
9506   /* If an error was already reported for one of the arguments,
9507      avoid reporting another error.  */
9508
9509   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9510     return error_mark_node;
9511
9512   if ((invalid_op_diag
9513        = targetm.invalid_binary_op (code, type0, type1)))
9514     {
9515       error_at (location, invalid_op_diag);
9516       return error_mark_node;
9517     }
9518
9519   switch (code)
9520     {
9521     case PLUS_EXPR:
9522     case MINUS_EXPR:
9523     case MULT_EXPR:
9524     case TRUNC_DIV_EXPR:
9525     case CEIL_DIV_EXPR:
9526     case FLOOR_DIV_EXPR:
9527     case ROUND_DIV_EXPR:
9528     case EXACT_DIV_EXPR:
9529       may_need_excess_precision = true;
9530       break;
9531     default:
9532       may_need_excess_precision = false;
9533       break;
9534     }
9535   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
9536     {
9537       op0 = TREE_OPERAND (op0, 0);
9538       type0 = TREE_TYPE (op0);
9539     }
9540   else if (may_need_excess_precision
9541            && (eptype = excess_precision_type (type0)) != NULL_TREE)
9542     {
9543       type0 = eptype;
9544       op0 = convert (eptype, op0);
9545     }
9546   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
9547     {
9548       op1 = TREE_OPERAND (op1, 0);
9549       type1 = TREE_TYPE (op1);
9550     }
9551   else if (may_need_excess_precision
9552            && (eptype = excess_precision_type (type1)) != NULL_TREE)
9553     {
9554       type1 = eptype;
9555       op1 = convert (eptype, op1);
9556     }
9557
9558   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
9559
9560   switch (code)
9561     {
9562     case PLUS_EXPR:
9563       /* Handle the pointer + int case.  */
9564       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9565         {
9566           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
9567           goto return_build_binary_op;
9568         }
9569       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
9570         {
9571           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
9572           goto return_build_binary_op;
9573         }
9574       else
9575         common = 1;
9576       break;
9577
9578     case MINUS_EXPR:
9579       /* Subtraction of two similar pointers.
9580          We must subtract them as integers, then divide by object size.  */
9581       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
9582           && comp_target_types (location, type0, type1))
9583         {
9584           ret = pointer_diff (location, op0, op1);
9585           goto return_build_binary_op;
9586         }
9587       /* Handle pointer minus int.  Just like pointer plus int.  */
9588       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9589         {
9590           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
9591           goto return_build_binary_op;
9592         }
9593       else
9594         common = 1;
9595       break;
9596
9597     case MULT_EXPR:
9598       common = 1;
9599       break;
9600
9601     case TRUNC_DIV_EXPR:
9602     case CEIL_DIV_EXPR:
9603     case FLOOR_DIV_EXPR:
9604     case ROUND_DIV_EXPR:
9605     case EXACT_DIV_EXPR:
9606       warn_for_div_by_zero (location, op1);
9607
9608       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9609            || code0 == FIXED_POINT_TYPE
9610            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9611           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9612               || code1 == FIXED_POINT_TYPE
9613               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9614         {
9615           enum tree_code tcode0 = code0, tcode1 = code1;
9616
9617           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9618             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9619           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9620             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9621
9622           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9623               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9624             resultcode = RDIV_EXPR;
9625           else
9626             /* Although it would be tempting to shorten always here, that
9627                loses on some targets, since the modulo instruction is
9628                undefined if the quotient can't be represented in the
9629                computation mode.  We shorten only if unsigned or if
9630                dividing by something we know != -1.  */
9631             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9632                        || (TREE_CODE (op1) == INTEGER_CST
9633                            && !integer_all_onesp (op1)));
9634           common = 1;
9635         }
9636       break;
9637
9638     case BIT_AND_EXPR:
9639     case BIT_IOR_EXPR:
9640     case BIT_XOR_EXPR:
9641       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9642         shorten = -1;
9643       /* Allow vector types which are not floating point types.   */
9644       else if (code0 == VECTOR_TYPE
9645                && code1 == VECTOR_TYPE
9646                && !VECTOR_FLOAT_TYPE_P (type0)
9647                && !VECTOR_FLOAT_TYPE_P (type1))
9648         common = 1;
9649       break;
9650
9651     case TRUNC_MOD_EXPR:
9652     case FLOOR_MOD_EXPR:
9653       warn_for_div_by_zero (location, op1);
9654
9655       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9656           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9657           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9658         common = 1;
9659       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9660         {
9661           /* Although it would be tempting to shorten always here, that loses
9662              on some targets, since the modulo instruction is undefined if the
9663              quotient can't be represented in the computation mode.  We shorten
9664              only if unsigned or if dividing by something we know != -1.  */
9665           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9666                      || (TREE_CODE (op1) == INTEGER_CST
9667                          && !integer_all_onesp (op1)));
9668           common = 1;
9669         }
9670       break;
9671
9672     case TRUTH_ANDIF_EXPR:
9673     case TRUTH_ORIF_EXPR:
9674     case TRUTH_AND_EXPR:
9675     case TRUTH_OR_EXPR:
9676     case TRUTH_XOR_EXPR:
9677       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9678            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9679            || code0 == FIXED_POINT_TYPE)
9680           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9681               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9682               || code1 == FIXED_POINT_TYPE))
9683         {
9684           /* Result of these operations is always an int,
9685              but that does not mean the operands should be
9686              converted to ints!  */
9687           result_type = integer_type_node;
9688           op0 = c_common_truthvalue_conversion (location, op0);
9689           op1 = c_common_truthvalue_conversion (location, op1);
9690           converted = 1;
9691           boolean_op = true;
9692         }
9693       if (code == TRUTH_ANDIF_EXPR)
9694         {
9695           int_const_or_overflow = (int_operands
9696                                    && TREE_CODE (orig_op0) == INTEGER_CST
9697                                    && (op0 == truthvalue_false_node
9698                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9699           int_const = (int_const_or_overflow
9700                        && !TREE_OVERFLOW (orig_op0)
9701                        && (op0 == truthvalue_false_node
9702                            || !TREE_OVERFLOW (orig_op1)));
9703         }
9704       else if (code == TRUTH_ORIF_EXPR)
9705         {
9706           int_const_or_overflow = (int_operands
9707                                    && TREE_CODE (orig_op0) == INTEGER_CST
9708                                    && (op0 == truthvalue_true_node
9709                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9710           int_const = (int_const_or_overflow
9711                        && !TREE_OVERFLOW (orig_op0)
9712                        && (op0 == truthvalue_true_node
9713                            || !TREE_OVERFLOW (orig_op1)));
9714         }
9715       break;
9716
9717       /* Shift operations: result has same type as first operand;
9718          always convert second operand to int.
9719          Also set SHORT_SHIFT if shifting rightward.  */
9720
9721     case RSHIFT_EXPR:
9722       if (code0 == VECTOR_TYPE && code1 == INTEGER_TYPE
9723           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE)
9724         {
9725           result_type = type0;
9726           converted = 1;
9727         }
9728       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9729           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9730           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE
9731           && TYPE_VECTOR_SUBPARTS (type0) == TYPE_VECTOR_SUBPARTS (type1))
9732         {
9733           result_type = type0;
9734           converted = 1;
9735         }
9736       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9737           && code1 == INTEGER_TYPE)
9738         {
9739           if (TREE_CODE (op1) == INTEGER_CST)
9740             {
9741               if (tree_int_cst_sgn (op1) < 0)
9742                 {
9743                   int_const = false;
9744                   if (c_inhibit_evaluation_warnings == 0)
9745                     warning (0, "right shift count is negative");
9746                 }
9747               else
9748                 {
9749                   if (!integer_zerop (op1))
9750                     short_shift = 1;
9751
9752                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9753                     {
9754                       int_const = false;
9755                       if (c_inhibit_evaluation_warnings == 0)
9756                         warning (0, "right shift count >= width of type");
9757                     }
9758                 }
9759             }
9760
9761           /* Use the type of the value to be shifted.  */
9762           result_type = type0;
9763           /* Convert the non vector shift-count to an integer, regardless
9764              of size of value being shifted.  */
9765           if (TREE_CODE (TREE_TYPE (op1)) != VECTOR_TYPE
9766               && TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9767             op1 = convert (integer_type_node, op1);
9768           /* Avoid converting op1 to result_type later.  */
9769           converted = 1;
9770         }
9771       break;
9772
9773     case LSHIFT_EXPR:
9774       if (code0 == VECTOR_TYPE && code1 == INTEGER_TYPE
9775           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE)
9776         {
9777           result_type = type0;
9778           converted = 1;
9779         }
9780       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9781           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9782           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE
9783           && TYPE_VECTOR_SUBPARTS (type0) == TYPE_VECTOR_SUBPARTS (type1))
9784         {
9785           result_type = type0;
9786           converted = 1;
9787         }
9788       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9789           && code1 == INTEGER_TYPE)
9790         {
9791           if (TREE_CODE (op1) == INTEGER_CST)
9792             {
9793               if (tree_int_cst_sgn (op1) < 0)
9794                 {
9795                   int_const = false;
9796                   if (c_inhibit_evaluation_warnings == 0)
9797                     warning (0, "left shift count is negative");
9798                 }
9799
9800               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9801                 {
9802                   int_const = false;
9803                   if (c_inhibit_evaluation_warnings == 0)
9804                     warning (0, "left shift count >= width of type");
9805                 }
9806             }
9807
9808           /* Use the type of the value to be shifted.  */
9809           result_type = type0;
9810           /* Convert the non vector shift-count to an integer, regardless
9811              of size of value being shifted.  */
9812           if (TREE_CODE (TREE_TYPE (op1)) != VECTOR_TYPE
9813               && TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9814             op1 = convert (integer_type_node, op1);
9815           /* Avoid converting op1 to result_type later.  */
9816           converted = 1;
9817         }
9818       break;
9819
9820     case EQ_EXPR:
9821     case NE_EXPR:
9822       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9823         warning_at (location,
9824                     OPT_Wfloat_equal,
9825                     "comparing floating point with == or != is unsafe");
9826       /* Result of comparison is always int,
9827          but don't convert the args to int!  */
9828       build_type = integer_type_node;
9829       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9830            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9831           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9832               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9833         short_compare = 1;
9834       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9835         {
9836           if (TREE_CODE (op0) == ADDR_EXPR
9837               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9838             {
9839               if (code == EQ_EXPR)
9840                 warning_at (location,
9841                             OPT_Waddress,
9842                             "the comparison will always evaluate as %<false%> "
9843                             "for the address of %qD will never be NULL",
9844                             TREE_OPERAND (op0, 0));
9845               else
9846                 warning_at (location,
9847                             OPT_Waddress,
9848                             "the comparison will always evaluate as %<true%> "
9849                             "for the address of %qD will never be NULL",
9850                             TREE_OPERAND (op0, 0));
9851             }
9852           result_type = type0;
9853         }
9854       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9855         {
9856           if (TREE_CODE (op1) == ADDR_EXPR
9857               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9858             {
9859               if (code == EQ_EXPR)
9860                 warning_at (location,
9861                             OPT_Waddress,
9862                             "the comparison will always evaluate as %<false%> "
9863                             "for the address of %qD will never be NULL",
9864                             TREE_OPERAND (op1, 0));
9865               else
9866                 warning_at (location,
9867                             OPT_Waddress,
9868                             "the comparison will always evaluate as %<true%> "
9869                             "for the address of %qD will never be NULL",
9870                             TREE_OPERAND (op1, 0));
9871             }
9872           result_type = type1;
9873         }
9874       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9875         {
9876           tree tt0 = TREE_TYPE (type0);
9877           tree tt1 = TREE_TYPE (type1);
9878           addr_space_t as0 = TYPE_ADDR_SPACE (tt0);
9879           addr_space_t as1 = TYPE_ADDR_SPACE (tt1);
9880           addr_space_t as_common = ADDR_SPACE_GENERIC;
9881
9882           /* Anything compares with void *.  void * compares with anything.
9883              Otherwise, the targets must be compatible
9884              and both must be object or both incomplete.  */
9885           if (comp_target_types (location, type0, type1))
9886             result_type = common_pointer_type (type0, type1);
9887           else if (!addr_space_superset (as0, as1, &as_common))
9888             {
9889               error_at (location, "comparison of pointers to "
9890                         "disjoint address spaces");
9891               return error_mark_node;
9892             }
9893           else if (VOID_TYPE_P (tt0))
9894             {
9895               if (pedantic && TREE_CODE (tt1) == FUNCTION_TYPE)
9896                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9897                          "comparison of %<void *%> with function pointer");
9898             }
9899           else if (VOID_TYPE_P (tt1))
9900             {
9901               if (pedantic && TREE_CODE (tt0) == FUNCTION_TYPE)
9902                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9903                          "comparison of %<void *%> with function pointer");
9904             }
9905           else
9906             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9907             if (!objc_ok)
9908               pedwarn (location, 0,
9909                        "comparison of distinct pointer types lacks a cast");
9910
9911           if (result_type == NULL_TREE)
9912             {
9913               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9914               result_type = build_pointer_type
9915                               (build_qualified_type (void_type_node, qual));
9916             }
9917         }
9918       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9919         {
9920           result_type = type0;
9921           pedwarn (location, 0, "comparison between pointer and integer");
9922         }
9923       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9924         {
9925           result_type = type1;
9926           pedwarn (location, 0, "comparison between pointer and integer");
9927         }
9928       break;
9929
9930     case LE_EXPR:
9931     case GE_EXPR:
9932     case LT_EXPR:
9933     case GT_EXPR:
9934       build_type = integer_type_node;
9935       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9936            || code0 == FIXED_POINT_TYPE)
9937           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9938               || code1 == FIXED_POINT_TYPE))
9939         short_compare = 1;
9940       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9941         {
9942           addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (type0));
9943           addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
9944           addr_space_t as_common;
9945
9946           if (comp_target_types (location, type0, type1))
9947             {
9948               result_type = common_pointer_type (type0, type1);
9949               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9950                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9951                 pedwarn (location, 0,
9952                          "comparison of complete and incomplete pointers");
9953               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9954                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9955                          "ordered comparisons of pointers to functions");
9956               else if (null_pointer_constant_p (orig_op0)
9957                        || null_pointer_constant_p (orig_op1))
9958                 warning_at (location, OPT_Wextra,
9959                             "ordered comparison of pointer with null pointer");
9960
9961             }
9962           else if (!addr_space_superset (as0, as1, &as_common))
9963             {
9964               error_at (location, "comparison of pointers to "
9965                         "disjoint address spaces");
9966               return error_mark_node;
9967             }
9968           else
9969             {
9970               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9971               result_type = build_pointer_type
9972                               (build_qualified_type (void_type_node, qual));
9973               pedwarn (location, 0,
9974                        "comparison of distinct pointer types lacks a cast");
9975             }
9976         }
9977       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9978         {
9979           result_type = type0;
9980           if (pedantic)
9981             pedwarn (location, OPT_pedantic,
9982                      "ordered comparison of pointer with integer zero");
9983           else if (extra_warnings)
9984             warning_at (location, OPT_Wextra,
9985                         "ordered comparison of pointer with integer zero");
9986         }
9987       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9988         {
9989           result_type = type1;
9990           if (pedantic)
9991             pedwarn (location, OPT_pedantic,
9992                      "ordered comparison of pointer with integer zero");
9993           else if (extra_warnings)
9994             warning_at (location, OPT_Wextra,
9995                         "ordered comparison of pointer with integer zero");
9996         }
9997       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9998         {
9999           result_type = type0;
10000           pedwarn (location, 0, "comparison between pointer and integer");
10001         }
10002       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
10003         {
10004           result_type = type1;
10005           pedwarn (location, 0, "comparison between pointer and integer");
10006         }
10007       break;
10008
10009     default:
10010       gcc_unreachable ();
10011     }
10012
10013   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
10014     return error_mark_node;
10015
10016   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
10017       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
10018           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
10019                                                     TREE_TYPE (type1))))
10020     {
10021       binary_op_error (location, code, type0, type1);
10022       return error_mark_node;
10023     }
10024
10025   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
10026        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
10027       &&
10028       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
10029        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
10030     {
10031       bool first_complex = (code0 == COMPLEX_TYPE);
10032       bool second_complex = (code1 == COMPLEX_TYPE);
10033       int none_complex = (!first_complex && !second_complex);
10034
10035       if (shorten || common || short_compare)
10036         {
10037           result_type = c_common_type (type0, type1);
10038           do_warn_double_promotion (result_type, type0, type1,
10039                                     "implicit conversion from %qT to %qT "
10040                                     "to match other operand of binary "
10041                                     "expression",
10042                                     location);
10043           if (result_type == error_mark_node)
10044             return error_mark_node;
10045         }
10046
10047       if (first_complex != second_complex
10048           && (code == PLUS_EXPR
10049               || code == MINUS_EXPR
10050               || code == MULT_EXPR
10051               || (code == TRUNC_DIV_EXPR && first_complex))
10052           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
10053           && flag_signed_zeros)
10054         {
10055           /* An operation on mixed real/complex operands must be
10056              handled specially, but the language-independent code can
10057              more easily optimize the plain complex arithmetic if
10058              -fno-signed-zeros.  */
10059           tree real_type = TREE_TYPE (result_type);
10060           tree real, imag;
10061           if (type0 != orig_type0 || type1 != orig_type1)
10062             {
10063               gcc_assert (may_need_excess_precision && common);
10064               semantic_result_type = c_common_type (orig_type0, orig_type1);
10065             }
10066           if (first_complex)
10067             {
10068               if (TREE_TYPE (op0) != result_type)
10069                 op0 = convert_and_check (result_type, op0);
10070               if (TREE_TYPE (op1) != real_type)
10071                 op1 = convert_and_check (real_type, op1);
10072             }
10073           else
10074             {
10075               if (TREE_TYPE (op0) != real_type)
10076                 op0 = convert_and_check (real_type, op0);
10077               if (TREE_TYPE (op1) != result_type)
10078                 op1 = convert_and_check (result_type, op1);
10079             }
10080           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
10081             return error_mark_node;
10082           if (first_complex)
10083             {
10084               op0 = c_save_expr (op0);
10085               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
10086                                      op0, 1);
10087               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
10088                                      op0, 1);
10089               switch (code)
10090                 {
10091                 case MULT_EXPR:
10092                 case TRUNC_DIV_EXPR:
10093                   imag = build2 (resultcode, real_type, imag, op1);
10094                   /* Fall through.  */
10095                 case PLUS_EXPR:
10096                 case MINUS_EXPR:
10097                   real = build2 (resultcode, real_type, real, op1);
10098                   break;
10099                 default:
10100                   gcc_unreachable();
10101                 }
10102             }
10103           else
10104             {
10105               op1 = c_save_expr (op1);
10106               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
10107                                      op1, 1);
10108               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
10109                                      op1, 1);
10110               switch (code)
10111                 {
10112                 case MULT_EXPR:
10113                   imag = build2 (resultcode, real_type, op0, imag);
10114                   /* Fall through.  */
10115                 case PLUS_EXPR:
10116                   real = build2 (resultcode, real_type, op0, real);
10117                   break;
10118                 case MINUS_EXPR:
10119                   real = build2 (resultcode, real_type, op0, real);
10120                   imag = build1 (NEGATE_EXPR, real_type, imag);
10121                   break;
10122                 default:
10123                   gcc_unreachable();
10124                 }
10125             }
10126           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
10127           goto return_build_binary_op;
10128         }
10129
10130       /* For certain operations (which identify themselves by shorten != 0)
10131          if both args were extended from the same smaller type,
10132          do the arithmetic in that type and then extend.
10133
10134          shorten !=0 and !=1 indicates a bitwise operation.
10135          For them, this optimization is safe only if
10136          both args are zero-extended or both are sign-extended.
10137          Otherwise, we might change the result.
10138          Eg, (short)-1 | (unsigned short)-1 is (int)-1
10139          but calculated in (unsigned short) it would be (unsigned short)-1.  */
10140
10141       if (shorten && none_complex)
10142         {
10143           final_type = result_type;
10144           result_type = shorten_binary_op (result_type, op0, op1,
10145                                            shorten == -1);
10146         }
10147
10148       /* Shifts can be shortened if shifting right.  */
10149
10150       if (short_shift)
10151         {
10152           int unsigned_arg;
10153           tree arg0 = get_narrower (op0, &unsigned_arg);
10154
10155           final_type = result_type;
10156
10157           if (arg0 == op0 && final_type == TREE_TYPE (op0))
10158             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
10159
10160           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
10161               && tree_int_cst_sgn (op1) > 0
10162               /* We can shorten only if the shift count is less than the
10163                  number of bits in the smaller type size.  */
10164               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
10165               /* We cannot drop an unsigned shift after sign-extension.  */
10166               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
10167             {
10168               /* Do an unsigned shift if the operand was zero-extended.  */
10169               result_type
10170                 = c_common_signed_or_unsigned_type (unsigned_arg,
10171                                                     TREE_TYPE (arg0));
10172               /* Convert value-to-be-shifted to that type.  */
10173               if (TREE_TYPE (op0) != result_type)
10174                 op0 = convert (result_type, op0);
10175               converted = 1;
10176             }
10177         }
10178
10179       /* Comparison operations are shortened too but differently.
10180          They identify themselves by setting short_compare = 1.  */
10181
10182       if (short_compare)
10183         {
10184           /* Don't write &op0, etc., because that would prevent op0
10185              from being kept in a register.
10186              Instead, make copies of the our local variables and
10187              pass the copies by reference, then copy them back afterward.  */
10188           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
10189           enum tree_code xresultcode = resultcode;
10190           tree val
10191             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
10192
10193           if (val != 0)
10194             {
10195               ret = val;
10196               goto return_build_binary_op;
10197             }
10198
10199           op0 = xop0, op1 = xop1;
10200           converted = 1;
10201           resultcode = xresultcode;
10202
10203           if (c_inhibit_evaluation_warnings == 0)
10204             {
10205               bool op0_maybe_const = true;
10206               bool op1_maybe_const = true;
10207               tree orig_op0_folded, orig_op1_folded;
10208
10209               if (in_late_binary_op)
10210                 {
10211                   orig_op0_folded = orig_op0;
10212                   orig_op1_folded = orig_op1;
10213                 }
10214               else
10215                 {
10216                   /* Fold for the sake of possible warnings, as in
10217                      build_conditional_expr.  This requires the
10218                      "original" values to be folded, not just op0 and
10219                      op1.  */
10220                   c_inhibit_evaluation_warnings++;
10221                   op0 = c_fully_fold (op0, require_constant_value,
10222                                       &op0_maybe_const);
10223                   op1 = c_fully_fold (op1, require_constant_value,
10224                                       &op1_maybe_const);
10225                   c_inhibit_evaluation_warnings--;
10226                   orig_op0_folded = c_fully_fold (orig_op0,
10227                                                   require_constant_value,
10228                                                   NULL);
10229                   orig_op1_folded = c_fully_fold (orig_op1,
10230                                                   require_constant_value,
10231                                                   NULL);
10232                 }
10233
10234               if (warn_sign_compare)
10235                 warn_for_sign_compare (location, orig_op0_folded,
10236                                        orig_op1_folded, op0, op1,
10237                                        result_type, resultcode);
10238               if (!in_late_binary_op)
10239                 {
10240                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
10241                     op0 = c_wrap_maybe_const (op0, !op0_maybe_const);
10242                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
10243                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
10244                 }
10245             }
10246         }
10247     }
10248
10249   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
10250      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
10251      Then the expression will be built.
10252      It will be given type FINAL_TYPE if that is nonzero;
10253      otherwise, it will be given type RESULT_TYPE.  */
10254
10255   if (!result_type)
10256     {
10257       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
10258       return error_mark_node;
10259     }
10260
10261   if (build_type == NULL_TREE)
10262     {
10263       build_type = result_type;
10264       if ((type0 != orig_type0 || type1 != orig_type1)
10265           && !boolean_op)
10266         {
10267           gcc_assert (may_need_excess_precision && common);
10268           semantic_result_type = c_common_type (orig_type0, orig_type1);
10269         }
10270     }
10271
10272   if (!converted)
10273     {
10274       op0 = ep_convert_and_check (result_type, op0, semantic_result_type);
10275       op1 = ep_convert_and_check (result_type, op1, semantic_result_type);
10276
10277       /* This can happen if one operand has a vector type, and the other
10278          has a different type.  */
10279       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
10280         return error_mark_node;
10281     }
10282
10283   /* Treat expressions in initializers specially as they can't trap.  */
10284   if (int_const_or_overflow)
10285     ret = (require_constant_value
10286            ? fold_build2_initializer_loc (location, resultcode, build_type,
10287                                           op0, op1)
10288            : fold_build2_loc (location, resultcode, build_type, op0, op1));
10289   else
10290     ret = build2 (resultcode, build_type, op0, op1);
10291   if (final_type != 0)
10292     ret = convert (final_type, ret);
10293
10294  return_build_binary_op:
10295   gcc_assert (ret != error_mark_node);
10296   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
10297     ret = (int_operands
10298            ? note_integer_operands (ret)
10299            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
10300   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
10301            && !in_late_binary_op)
10302     ret = note_integer_operands (ret);
10303   if (semantic_result_type)
10304     ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
10305   protected_set_expr_location (ret, location);
10306   return ret;
10307 }
10308
10309
10310 /* Convert EXPR to be a truth-value, validating its type for this
10311    purpose.  LOCATION is the source location for the expression.  */
10312
10313 tree
10314 c_objc_common_truthvalue_conversion (location_t location, tree expr)
10315 {
10316   bool int_const, int_operands;
10317
10318   switch (TREE_CODE (TREE_TYPE (expr)))
10319     {
10320     case ARRAY_TYPE:
10321       error_at (location, "used array that cannot be converted to pointer where scalar is required");
10322       return error_mark_node;
10323
10324     case RECORD_TYPE:
10325       error_at (location, "used struct type value where scalar is required");
10326       return error_mark_node;
10327
10328     case UNION_TYPE:
10329       error_at (location, "used union type value where scalar is required");
10330       return error_mark_node;
10331
10332     case FUNCTION_TYPE:
10333       gcc_unreachable ();
10334
10335     default:
10336       break;
10337     }
10338
10339   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
10340   int_operands = EXPR_INT_CONST_OPERANDS (expr);
10341   if (int_operands)
10342     expr = remove_c_maybe_const_expr (expr);
10343
10344   /* ??? Should we also give an error for void and vectors rather than
10345      leaving those to give errors later?  */
10346   expr = c_common_truthvalue_conversion (location, expr);
10347
10348   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
10349     {
10350       if (TREE_OVERFLOW (expr))
10351         return expr;
10352       else
10353         return note_integer_operands (expr);
10354     }
10355   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
10356     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
10357   return expr;
10358 }
10359 \f
10360
10361 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
10362    required.  */
10363
10364 tree
10365 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
10366 {
10367   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
10368     {
10369       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
10370       /* Executing a compound literal inside a function reinitializes
10371          it.  */
10372       if (!TREE_STATIC (decl))
10373         *se = true;
10374       return decl;
10375     }
10376   else
10377     return expr;
10378 }
10379 \f
10380 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
10381
10382 tree
10383 c_begin_omp_parallel (void)
10384 {
10385   tree block;
10386
10387   keep_next_level ();
10388   block = c_begin_compound_stmt (true);
10389
10390   return block;
10391 }
10392
10393 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
10394    statement.  LOC is the location of the OMP_PARALLEL.  */
10395
10396 tree
10397 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
10398 {
10399   tree stmt;
10400
10401   block = c_end_compound_stmt (loc, block, true);
10402
10403   stmt = make_node (OMP_PARALLEL);
10404   TREE_TYPE (stmt) = void_type_node;
10405   OMP_PARALLEL_CLAUSES (stmt) = clauses;
10406   OMP_PARALLEL_BODY (stmt) = block;
10407   SET_EXPR_LOCATION (stmt, loc);
10408
10409   return add_stmt (stmt);
10410 }
10411
10412 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
10413
10414 tree
10415 c_begin_omp_task (void)
10416 {
10417   tree block;
10418
10419   keep_next_level ();
10420   block = c_begin_compound_stmt (true);
10421
10422   return block;
10423 }
10424
10425 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
10426    statement.  LOC is the location of the #pragma.  */
10427
10428 tree
10429 c_finish_omp_task (location_t loc, tree clauses, tree block)
10430 {
10431   tree stmt;
10432
10433   block = c_end_compound_stmt (loc, block, true);
10434
10435   stmt = make_node (OMP_TASK);
10436   TREE_TYPE (stmt) = void_type_node;
10437   OMP_TASK_CLAUSES (stmt) = clauses;
10438   OMP_TASK_BODY (stmt) = block;
10439   SET_EXPR_LOCATION (stmt, loc);
10440
10441   return add_stmt (stmt);
10442 }
10443
10444 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
10445    Remove any elements from the list that are invalid.  */
10446
10447 tree
10448 c_finish_omp_clauses (tree clauses)
10449 {
10450   bitmap_head generic_head, firstprivate_head, lastprivate_head;
10451   tree c, t, *pc = &clauses;
10452   const char *name;
10453
10454   bitmap_obstack_initialize (NULL);
10455   bitmap_initialize (&generic_head, &bitmap_default_obstack);
10456   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
10457   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
10458
10459   for (pc = &clauses, c = clauses; c ; c = *pc)
10460     {
10461       bool remove = false;
10462       bool need_complete = false;
10463       bool need_implicitly_determined = false;
10464
10465       switch (OMP_CLAUSE_CODE (c))
10466         {
10467         case OMP_CLAUSE_SHARED:
10468           name = "shared";
10469           need_implicitly_determined = true;
10470           goto check_dup_generic;
10471
10472         case OMP_CLAUSE_PRIVATE:
10473           name = "private";
10474           need_complete = true;
10475           need_implicitly_determined = true;
10476           goto check_dup_generic;
10477
10478         case OMP_CLAUSE_REDUCTION:
10479           name = "reduction";
10480           need_implicitly_determined = true;
10481           t = OMP_CLAUSE_DECL (c);
10482           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
10483               || POINTER_TYPE_P (TREE_TYPE (t)))
10484             {
10485               error_at (OMP_CLAUSE_LOCATION (c),
10486                         "%qE has invalid type for %<reduction%>", t);
10487               remove = true;
10488             }
10489           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
10490             {
10491               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
10492               const char *r_name = NULL;
10493
10494               switch (r_code)
10495                 {
10496                 case PLUS_EXPR:
10497                 case MULT_EXPR:
10498                 case MINUS_EXPR:
10499                   break;
10500                 case BIT_AND_EXPR:
10501                   r_name = "&";
10502                   break;
10503                 case BIT_XOR_EXPR:
10504                   r_name = "^";
10505                   break;
10506                 case BIT_IOR_EXPR:
10507                   r_name = "|";
10508                   break;
10509                 case TRUTH_ANDIF_EXPR:
10510                   r_name = "&&";
10511                   break;
10512                 case TRUTH_ORIF_EXPR:
10513                   r_name = "||";
10514                   break;
10515                 default:
10516                   gcc_unreachable ();
10517                 }
10518               if (r_name)
10519                 {
10520                   error_at (OMP_CLAUSE_LOCATION (c),
10521                             "%qE has invalid type for %<reduction(%s)%>",
10522                             t, r_name);
10523                   remove = true;
10524                 }
10525             }
10526           goto check_dup_generic;
10527
10528         case OMP_CLAUSE_COPYPRIVATE:
10529           name = "copyprivate";
10530           goto check_dup_generic;
10531
10532         case OMP_CLAUSE_COPYIN:
10533           name = "copyin";
10534           t = OMP_CLAUSE_DECL (c);
10535           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
10536             {
10537               error_at (OMP_CLAUSE_LOCATION (c),
10538                         "%qE must be %<threadprivate%> for %<copyin%>", t);
10539               remove = true;
10540             }
10541           goto check_dup_generic;
10542
10543         check_dup_generic:
10544           t = OMP_CLAUSE_DECL (c);
10545           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10546             {
10547               error_at (OMP_CLAUSE_LOCATION (c),
10548                         "%qE is not a variable in clause %qs", t, name);
10549               remove = true;
10550             }
10551           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10552                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
10553                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10554             {
10555               error_at (OMP_CLAUSE_LOCATION (c),
10556                         "%qE appears more than once in data clauses", t);
10557               remove = true;
10558             }
10559           else
10560             bitmap_set_bit (&generic_head, DECL_UID (t));
10561           break;
10562
10563         case OMP_CLAUSE_FIRSTPRIVATE:
10564           name = "firstprivate";
10565           t = OMP_CLAUSE_DECL (c);
10566           need_complete = true;
10567           need_implicitly_determined = true;
10568           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10569             {
10570               error_at (OMP_CLAUSE_LOCATION (c),
10571                         "%qE is not a variable in clause %<firstprivate%>", t);
10572               remove = true;
10573             }
10574           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10575                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
10576             {
10577               error_at (OMP_CLAUSE_LOCATION (c),
10578                         "%qE appears more than once in data clauses", t);
10579               remove = true;
10580             }
10581           else
10582             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
10583           break;
10584
10585         case OMP_CLAUSE_LASTPRIVATE:
10586           name = "lastprivate";
10587           t = OMP_CLAUSE_DECL (c);
10588           need_complete = true;
10589           need_implicitly_determined = true;
10590           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10591             {
10592               error_at (OMP_CLAUSE_LOCATION (c),
10593                         "%qE is not a variable in clause %<lastprivate%>", t);
10594               remove = true;
10595             }
10596           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10597                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10598             {
10599               error_at (OMP_CLAUSE_LOCATION (c),
10600                      "%qE appears more than once in data clauses", t);
10601               remove = true;
10602             }
10603           else
10604             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
10605           break;
10606
10607         case OMP_CLAUSE_IF:
10608         case OMP_CLAUSE_NUM_THREADS:
10609         case OMP_CLAUSE_SCHEDULE:
10610         case OMP_CLAUSE_NOWAIT:
10611         case OMP_CLAUSE_ORDERED:
10612         case OMP_CLAUSE_DEFAULT:
10613         case OMP_CLAUSE_UNTIED:
10614         case OMP_CLAUSE_COLLAPSE:
10615           pc = &OMP_CLAUSE_CHAIN (c);
10616           continue;
10617
10618         default:
10619           gcc_unreachable ();
10620         }
10621
10622       if (!remove)
10623         {
10624           t = OMP_CLAUSE_DECL (c);
10625
10626           if (need_complete)
10627             {
10628               t = require_complete_type (t);
10629               if (t == error_mark_node)
10630                 remove = true;
10631             }
10632
10633           if (need_implicitly_determined)
10634             {
10635               const char *share_name = NULL;
10636
10637               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
10638                 share_name = "threadprivate";
10639               else switch (c_omp_predetermined_sharing (t))
10640                 {
10641                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
10642                   break;
10643                 case OMP_CLAUSE_DEFAULT_SHARED:
10644                   share_name = "shared";
10645                   break;
10646                 case OMP_CLAUSE_DEFAULT_PRIVATE:
10647                   share_name = "private";
10648                   break;
10649                 default:
10650                   gcc_unreachable ();
10651                 }
10652               if (share_name)
10653                 {
10654                   error_at (OMP_CLAUSE_LOCATION (c),
10655                             "%qE is predetermined %qs for %qs",
10656                             t, share_name, name);
10657                   remove = true;
10658                 }
10659             }
10660         }
10661
10662       if (remove)
10663         *pc = OMP_CLAUSE_CHAIN (c);
10664       else
10665         pc = &OMP_CLAUSE_CHAIN (c);
10666     }
10667
10668   bitmap_obstack_release (NULL);
10669   return clauses;
10670 }
10671
10672 /* Make a variant type in the proper way for C/C++, propagating qualifiers
10673    down to the element type of an array.  */
10674
10675 tree
10676 c_build_qualified_type (tree type, int type_quals)
10677 {
10678   if (type == error_mark_node)
10679     return type;
10680
10681   if (TREE_CODE (type) == ARRAY_TYPE)
10682     {
10683       tree t;
10684       tree element_type = c_build_qualified_type (TREE_TYPE (type),
10685                                                   type_quals);
10686
10687       /* See if we already have an identically qualified type.  */
10688       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
10689         {
10690           if (TYPE_QUALS (strip_array_types (t)) == type_quals
10691               && TYPE_NAME (t) == TYPE_NAME (type)
10692               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
10693               && attribute_list_equal (TYPE_ATTRIBUTES (t),
10694                                        TYPE_ATTRIBUTES (type)))
10695             break;
10696         }
10697       if (!t)
10698         {
10699           tree domain = TYPE_DOMAIN (type);
10700
10701           t = build_variant_type_copy (type);
10702           TREE_TYPE (t) = element_type;
10703
10704           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
10705               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10706             SET_TYPE_STRUCTURAL_EQUALITY (t);
10707           else if (TYPE_CANONICAL (element_type) != element_type
10708                    || (domain && TYPE_CANONICAL (domain) != domain))
10709             {
10710               tree unqualified_canon
10711                 = build_array_type (TYPE_CANONICAL (element_type),
10712                                     domain? TYPE_CANONICAL (domain)
10713                                           : NULL_TREE);
10714               TYPE_CANONICAL (t)
10715                 = c_build_qualified_type (unqualified_canon, type_quals);
10716             }
10717           else
10718             TYPE_CANONICAL (t) = t;
10719         }
10720       return t;
10721     }
10722
10723   /* A restrict-qualified pointer type must be a pointer to object or
10724      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10725      REFERENCE_TYPEs, which is appropriate for C++.  */
10726   if ((type_quals & TYPE_QUAL_RESTRICT)
10727       && (!POINTER_TYPE_P (type)
10728           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10729     {
10730       error ("invalid use of %<restrict%>");
10731       type_quals &= ~TYPE_QUAL_RESTRICT;
10732     }
10733
10734   return build_qualified_type (type, type_quals);
10735 }
10736
10737 /* Build a VA_ARG_EXPR for the C parser.  */
10738
10739 tree
10740 c_build_va_arg (location_t loc, tree expr, tree type)
10741 {
10742   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10743     warning_at (loc, OPT_Wc___compat,
10744                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10745   return build_va_arg (loc, expr, type);
10746 }