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