gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "tree.h"
  33 #include "langhooks.h"
  34 #include "c-tree.h"
  35 #include "c-lang.h"
  36 #include "flags.h"
  37 #include "output.h"
  38 #include "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 (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 = targetm.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 (arg, ((code == PREINCREMENT_EXPR
3568                                      || code == POSTINCREMENT_EXPR)
3569                                     ? lv_increment
3570                                     : lv_decrement)))
3571         return error_mark_node;
3572
3573       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3574         {
3575           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3576             warning_at (location, OPT_Wc___compat,
3577                         "increment of enumeration value is invalid in C++");
3578           else
3579             warning_at (location, OPT_Wc___compat,
3580                         "decrement of enumeration value is invalid in C++");
3581         }
3582
3583       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3584       arg = c_fully_fold (arg, false, NULL);
3585
3586       /* Increment or decrement the real part of the value,
3587          and don't change the imaginary part.  */
3588       if (typecode == COMPLEX_TYPE)
3589         {
3590           tree real, imag;
3591
3592           pedwarn (location, OPT_pedantic,
3593                    "ISO C does not support %<++%> and %<--%> on complex types");
3594
3595           arg = stabilize_reference (arg);
3596           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3597           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3598           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3599           if (real == error_mark_node || imag == error_mark_node)
3600             return error_mark_node;
3601           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3602                         real, imag);
3603           goto return_build_unary_op;
3604         }
3605
3606       /* Report invalid types.  */
3607
3608       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3609           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3610         {
3611           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3612             error_at (location, "wrong type argument to increment");
3613           else
3614             error_at (location, "wrong type argument to decrement");
3615
3616           return error_mark_node;
3617         }
3618
3619       {
3620         tree inc;
3621
3622         argtype = TREE_TYPE (arg);
3623
3624         /* Compute the increment.  */
3625
3626         if (typecode == POINTER_TYPE)
3627           {
3628             /* If pointer target is an undefined struct,
3629                we just cannot know how to do the arithmetic.  */
3630             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3631               {
3632                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3633                   error_at (location,
3634                             "increment of pointer to unknown structure");
3635                 else
3636                   error_at (location,
3637                             "decrement of pointer to unknown structure");
3638               }
3639             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3640                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3641               {
3642                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3643                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3644                            "wrong type argument to increment");
3645                 else
3646                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3647                            "wrong type argument to decrement");
3648               }
3649
3650             inc = c_size_in_bytes (TREE_TYPE (argtype));
3651             inc = fold_convert_loc (location, sizetype, inc);
3652           }
3653         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3654           {
3655             /* For signed fract types, we invert ++ to -- or
3656                -- to ++, and change inc from 1 to -1, because
3657                it is not possible to represent 1 in signed fract constants.
3658                For unsigned fract types, the result always overflows and
3659                we get an undefined (original) or the maximum value.  */
3660             if (code == PREINCREMENT_EXPR)
3661               code = PREDECREMENT_EXPR;
3662             else if (code == PREDECREMENT_EXPR)
3663               code = PREINCREMENT_EXPR;
3664             else if (code == POSTINCREMENT_EXPR)
3665               code = POSTDECREMENT_EXPR;
3666             else /* code == POSTDECREMENT_EXPR  */
3667               code = POSTINCREMENT_EXPR;
3668
3669             inc = integer_minus_one_node;
3670             inc = convert (argtype, inc);
3671           }
3672         else
3673           {
3674             inc = integer_one_node;
3675             inc = convert (argtype, inc);
3676           }
3677
3678         /* If 'arg' is an Objective-C PROPERTY_REF expression, then we
3679            need to ask Objective-C to build the increment or decrement
3680            expression for it.  */
3681         if (objc_is_property_ref (arg))
3682           return objc_build_incr_expr_for_property_ref (location, code,
3683                                                         arg, inc);
3684
3685         /* Report a read-only lvalue.  */
3686         if (TYPE_READONLY (argtype))
3687           {
3688             readonly_error (arg,
3689                             ((code == PREINCREMENT_EXPR
3690                               || code == POSTINCREMENT_EXPR)
3691                              ? lv_increment : lv_decrement));
3692             return error_mark_node;
3693           }
3694         else if (TREE_READONLY (arg))
3695           readonly_warning (arg,
3696                             ((code == PREINCREMENT_EXPR
3697                               || code == POSTINCREMENT_EXPR)
3698                              ? lv_increment : lv_decrement));
3699
3700         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3701           val = boolean_increment (code, arg);
3702         else
3703           val = build2 (code, TREE_TYPE (arg), arg, inc);
3704         TREE_SIDE_EFFECTS (val) = 1;
3705         if (TREE_CODE (val) != code)
3706           TREE_NO_WARNING (val) = 1;
3707         ret = val;
3708         goto return_build_unary_op;
3709       }
3710
3711     case ADDR_EXPR:
3712       /* Note that this operation never does default_conversion.  */
3713
3714       /* The operand of unary '&' must be an lvalue (which excludes
3715          expressions of type void), or, in C99, the result of a [] or
3716          unary '*' operator.  */
3717       if (VOID_TYPE_P (TREE_TYPE (arg))
3718           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3719           && (TREE_CODE (arg) != INDIRECT_REF
3720               || !flag_isoc99))
3721         pedwarn (location, 0, "taking address of expression of type %<void%>");
3722
3723       /* Let &* cancel out to simplify resulting code.  */
3724       if (TREE_CODE (arg) == INDIRECT_REF)
3725         {
3726           /* Don't let this be an lvalue.  */
3727           if (lvalue_p (TREE_OPERAND (arg, 0)))
3728             return non_lvalue_loc (location, TREE_OPERAND (arg, 0));
3729           ret = TREE_OPERAND (arg, 0);
3730           goto return_build_unary_op;
3731         }
3732
3733       /* For &x[y], return x+y */
3734       if (TREE_CODE (arg) == ARRAY_REF)
3735         {
3736           tree op0 = TREE_OPERAND (arg, 0);
3737           if (!c_mark_addressable (op0))
3738             return error_mark_node;
3739           return build_binary_op (location, PLUS_EXPR,
3740                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3741                                    ? array_to_pointer_conversion (location,
3742                                                                   op0)
3743                                    : op0),
3744                                   TREE_OPERAND (arg, 1), 1);
3745         }
3746
3747       /* Anything not already handled and not a true memory reference
3748          or a non-lvalue array is an error.  */
3749       else if (typecode != FUNCTION_TYPE && !flag
3750                && !lvalue_or_else (arg, lv_addressof))
3751         return error_mark_node;
3752
3753       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3754          folding later.  */
3755       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3756         {
3757           tree inner = build_unary_op (location, code,
3758                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3759           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3760                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3761           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3762           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3763             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3764           goto return_build_unary_op;
3765         }
3766
3767       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3768       argtype = TREE_TYPE (arg);
3769
3770       /* If the lvalue is const or volatile, merge that into the type
3771          to which the address will point.  This should only be needed
3772          for function types.  */
3773       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3774           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3775         {
3776           int orig_quals = TYPE_QUALS (strip_array_types (argtype));
3777           int quals = orig_quals;
3778
3779           if (TREE_READONLY (arg))
3780             quals |= TYPE_QUAL_CONST;
3781           if (TREE_THIS_VOLATILE (arg))
3782             quals |= TYPE_QUAL_VOLATILE;
3783
3784           gcc_assert (quals == orig_quals
3785                       || TREE_CODE (argtype) == FUNCTION_TYPE);
3786
3787           argtype = c_build_qualified_type (argtype, quals);
3788         }
3789
3790       if (!c_mark_addressable (arg))
3791         return error_mark_node;
3792
3793       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3794                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3795
3796       argtype = build_pointer_type (argtype);
3797
3798       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3799          when we have proper support for integer constant expressions.  */
3800       val = get_base_address (arg);
3801       if (val && TREE_CODE (val) == INDIRECT_REF
3802           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3803         {
3804           tree op0 = fold_convert_loc (location, sizetype,
3805                                        fold_offsetof (arg, val)), op1;
3806
3807           op1 = fold_convert_loc (location, argtype, TREE_OPERAND (val, 0));
3808           ret = fold_build2_loc (location, POINTER_PLUS_EXPR, argtype, op1, op0);
3809           goto return_build_unary_op;
3810         }
3811
3812       val = build1 (ADDR_EXPR, argtype, arg);
3813
3814       ret = val;
3815       goto return_build_unary_op;
3816
3817     default:
3818       gcc_unreachable ();
3819     }
3820
3821   if (argtype == 0)
3822     argtype = TREE_TYPE (arg);
3823   if (TREE_CODE (arg) == INTEGER_CST)
3824     ret = (require_constant_value
3825            ? fold_build1_initializer_loc (location, code, argtype, arg)
3826            : fold_build1_loc (location, code, argtype, arg));
3827   else
3828     ret = build1 (code, argtype, arg);
3829  return_build_unary_op:
3830   gcc_assert (ret != error_mark_node);
3831   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3832       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3833     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3834   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3835     ret = note_integer_operands (ret);
3836   if (eptype)
3837     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3838   protected_set_expr_location (ret, location);
3839   return ret;
3840 }
3841
3842 /* Return nonzero if REF is an lvalue valid for this language.
3843    Lvalues can be assigned, unless their type has TYPE_READONLY.
3844    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3845
3846 bool
3847 lvalue_p (const_tree ref)
3848 {
3849   const enum tree_code code = TREE_CODE (ref);
3850
3851   switch (code)
3852     {
3853     case REALPART_EXPR:
3854     case IMAGPART_EXPR:
3855     case COMPONENT_REF:
3856       return lvalue_p (TREE_OPERAND (ref, 0));
3857
3858     case C_MAYBE_CONST_EXPR:
3859       return lvalue_p (TREE_OPERAND (ref, 1));
3860
3861     case COMPOUND_LITERAL_EXPR:
3862     case STRING_CST:
3863       return 1;
3864
3865     case INDIRECT_REF:
3866     case ARRAY_REF:
3867     case VAR_DECL:
3868     case PARM_DECL:
3869     case RESULT_DECL:
3870     case ERROR_MARK:
3871       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3872               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3873
3874     case BIND_EXPR:
3875       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3876
3877     default:
3878       return 0;
3879     }
3880 }
3881 \f
3882 /* Give a warning for storing in something that is read-only in GCC
3883    terms but not const in ISO C terms.  */
3884
3885 static void
3886 readonly_warning (tree arg, enum lvalue_use use)
3887 {
3888   switch (use)
3889     {
3890     case lv_assign:
3891       warning (0, "assignment of read-only location %qE", arg);
3892       break;
3893     case lv_increment:
3894       warning (0, "increment of read-only location %qE", arg);
3895       break;
3896     case lv_decrement:
3897       warning (0, "decrement of read-only location %qE", arg);
3898       break;
3899     default:
3900       gcc_unreachable ();
3901     }
3902   return;
3903 }
3904
3905
3906 /* Return nonzero if REF is an lvalue valid for this language;
3907    otherwise, print an error message and return zero.  USE says
3908    how the lvalue is being used and so selects the error message.  */
3909
3910 static int
3911 lvalue_or_else (const_tree ref, enum lvalue_use use)
3912 {
3913   int win = lvalue_p (ref);
3914
3915   if (!win)
3916     lvalue_error (use);
3917
3918   return win;
3919 }
3920 \f
3921 /* Mark EXP saying that we need to be able to take the
3922    address of it; it should not be allocated in a register.
3923    Returns true if successful.  */
3924
3925 bool
3926 c_mark_addressable (tree exp)
3927 {
3928   tree x = exp;
3929
3930   while (1)
3931     switch (TREE_CODE (x))
3932       {
3933       case COMPONENT_REF:
3934         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3935           {
3936             error
3937               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3938             return false;
3939           }
3940
3941         /* ... fall through ...  */
3942
3943       case ADDR_EXPR:
3944       case ARRAY_REF:
3945       case REALPART_EXPR:
3946       case IMAGPART_EXPR:
3947         x = TREE_OPERAND (x, 0);
3948         break;
3949
3950       case COMPOUND_LITERAL_EXPR:
3951       case CONSTRUCTOR:
3952         TREE_ADDRESSABLE (x) = 1;
3953         return true;
3954
3955       case VAR_DECL:
3956       case CONST_DECL:
3957       case PARM_DECL:
3958       case RESULT_DECL:
3959         if (C_DECL_REGISTER (x)
3960             && DECL_NONLOCAL (x))
3961           {
3962             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3963               {
3964                 error
3965                   ("global register variable %qD used in nested function", x);
3966                 return false;
3967               }
3968             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3969           }
3970         else if (C_DECL_REGISTER (x))
3971           {
3972             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3973               error ("address of global register variable %qD requested", x);
3974             else
3975               error ("address of register variable %qD requested", x);
3976             return false;
3977           }
3978
3979         /* drops in */
3980       case FUNCTION_DECL:
3981         TREE_ADDRESSABLE (x) = 1;
3982         /* drops out */
3983       default:
3984         return true;
3985     }
3986 }
3987 \f
3988 /* Convert EXPR to TYPE, warning about conversion problems with
3989    constants.  SEMANTIC_TYPE is the type this conversion would use
3990    without excess precision. If SEMANTIC_TYPE is NULL, this function
3991    is equivalent to convert_and_check. This function is a wrapper that
3992    handles conversions that may be different than
3993    the usual ones because of excess precision.  */
3994
3995 static tree
3996 ep_convert_and_check (tree type, tree expr, tree semantic_type)
3997 {
3998   if (TREE_TYPE (expr) == type)
3999     return expr;
4000
4001   if (!semantic_type)
4002     return convert_and_check (type, expr);
4003
4004   if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
4005       && TREE_TYPE (expr) != semantic_type)
4006     {
4007       /* For integers, we need to check the real conversion, not
4008          the conversion to the excess precision type.  */
4009       expr = convert_and_check (semantic_type, expr);
4010     }
4011   /* Result type is the excess precision type, which should be
4012      large enough, so do not check.  */
4013   return convert (type, expr);
4014 }
4015
4016 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
4017    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
4018    if folded to an integer constant then the unselected half may
4019    contain arbitrary operations not normally permitted in constant
4020    expressions.  Set the location of the expression to LOC.  */
4021
4022 tree
4023 build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
4024                         tree op1, tree op1_original_type, tree op2,
4025                         tree op2_original_type)
4026 {
4027   tree type1;
4028   tree type2;
4029   enum tree_code code1;
4030   enum tree_code code2;
4031   tree result_type = NULL;
4032   tree semantic_result_type = NULL;
4033   tree orig_op1 = op1, orig_op2 = op2;
4034   bool int_const, op1_int_operands, op2_int_operands, int_operands;
4035   bool ifexp_int_operands;
4036   tree ret;
4037
4038   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
4039   if (op1_int_operands)
4040     op1 = remove_c_maybe_const_expr (op1);
4041   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
4042   if (op2_int_operands)
4043     op2 = remove_c_maybe_const_expr (op2);
4044   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
4045   if (ifexp_int_operands)
4046     ifexp = remove_c_maybe_const_expr (ifexp);
4047
4048   /* Promote both alternatives.  */
4049
4050   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
4051     op1 = default_conversion (op1);
4052   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
4053     op2 = default_conversion (op2);
4054
4055   if (TREE_CODE (ifexp) == ERROR_MARK
4056       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
4057       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
4058     return error_mark_node;
4059
4060   type1 = TREE_TYPE (op1);
4061   code1 = TREE_CODE (type1);
4062   type2 = TREE_TYPE (op2);
4063   code2 = TREE_CODE (type2);
4064
4065   /* C90 does not permit non-lvalue arrays in conditional expressions.
4066      In C99 they will be pointers by now.  */
4067   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
4068     {
4069       error_at (colon_loc, "non-lvalue array in conditional expression");
4070       return error_mark_node;
4071     }
4072
4073   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
4074        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
4075       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
4076           || code1 == COMPLEX_TYPE)
4077       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
4078           || code2 == COMPLEX_TYPE))
4079     {
4080       semantic_result_type = c_common_type (type1, type2);
4081       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
4082         {
4083           op1 = TREE_OPERAND (op1, 0);
4084           type1 = TREE_TYPE (op1);
4085           gcc_assert (TREE_CODE (type1) == code1);
4086         }
4087       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
4088         {
4089           op2 = TREE_OPERAND (op2, 0);
4090           type2 = TREE_TYPE (op2);
4091           gcc_assert (TREE_CODE (type2) == code2);
4092         }
4093     }
4094
4095   if (warn_cxx_compat)
4096     {
4097       tree t1 = op1_original_type ? op1_original_type : TREE_TYPE (orig_op1);
4098       tree t2 = op2_original_type ? op2_original_type : TREE_TYPE (orig_op2);
4099
4100       if (TREE_CODE (t1) == ENUMERAL_TYPE
4101           && TREE_CODE (t2) == ENUMERAL_TYPE
4102           && TYPE_MAIN_VARIANT (t1) != TYPE_MAIN_VARIANT (t2))
4103         warning_at (colon_loc, OPT_Wc___compat,
4104                     ("different enum types in conditional is "
4105                      "invalid in C++: %qT vs %qT"),
4106                     t1, t2);
4107     }
4108
4109   /* Quickly detect the usual case where op1 and op2 have the same type
4110      after promotion.  */
4111   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
4112     {
4113       if (type1 == type2)
4114         result_type = type1;
4115       else
4116         result_type = TYPE_MAIN_VARIANT (type1);
4117     }
4118   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
4119             || code1 == COMPLEX_TYPE)
4120            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
4121                || code2 == COMPLEX_TYPE))
4122     {
4123       result_type = c_common_type (type1, type2);
4124       do_warn_double_promotion (result_type, type1, type2,
4125                                 "implicit conversion from %qT to %qT to "
4126                                 "match other result of conditional",
4127                                 colon_loc);
4128
4129       /* If -Wsign-compare, warn here if type1 and type2 have
4130          different signedness.  We'll promote the signed to unsigned
4131          and later code won't know it used to be different.
4132          Do this check on the original types, so that explicit casts
4133          will be considered, but default promotions won't.  */
4134       if (c_inhibit_evaluation_warnings == 0)
4135         {
4136           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
4137           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
4138
4139           if (unsigned_op1 ^ unsigned_op2)
4140             {
4141               bool ovf;
4142
4143               /* Do not warn if the result type is signed, since the
4144                  signed type will only be chosen if it can represent
4145                  all the values of the unsigned type.  */
4146               if (!TYPE_UNSIGNED (result_type))
4147                 /* OK */;
4148               else
4149                 {
4150                   bool op1_maybe_const = true;
4151                   bool op2_maybe_const = true;
4152
4153                   /* Do not warn if the signed quantity is an
4154                      unsuffixed integer literal (or some static
4155                      constant expression involving such literals) and
4156                      it is non-negative.  This warning requires the
4157                      operands to be folded for best results, so do
4158                      that folding in this case even without
4159                      warn_sign_compare to avoid warning options
4160                      possibly affecting code generation.  */
4161                   c_inhibit_evaluation_warnings
4162                     += (ifexp == truthvalue_false_node);
4163                   op1 = c_fully_fold (op1, require_constant_value,
4164                                       &op1_maybe_const);
4165                   c_inhibit_evaluation_warnings
4166                     -= (ifexp == truthvalue_false_node);
4167
4168                   c_inhibit_evaluation_warnings
4169                     += (ifexp == truthvalue_true_node);
4170                   op2 = c_fully_fold (op2, require_constant_value,
4171                                       &op2_maybe_const);
4172                   c_inhibit_evaluation_warnings
4173                     -= (ifexp == truthvalue_true_node);
4174
4175                   if (warn_sign_compare)
4176                     {
4177                       if ((unsigned_op2
4178                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
4179                           || (unsigned_op1
4180                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
4181                         /* OK */;
4182                       else
4183                         warning_at (colon_loc, OPT_Wsign_compare,
4184                                     ("signed and unsigned type in "
4185                                      "conditional expression"));
4186                     }
4187                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
4188                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
4189                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
4190                     op2 = c_wrap_maybe_const (op2, !op2_maybe_const);
4191                 }
4192             }
4193         }
4194     }
4195   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
4196     {
4197       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
4198         pedwarn (colon_loc, OPT_pedantic,
4199                  "ISO C forbids conditional expr with only one void side");
4200       result_type = void_type_node;
4201     }
4202   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
4203     {
4204       addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
4205       addr_space_t as2 = TYPE_ADDR_SPACE (TREE_TYPE (type2));
4206       addr_space_t as_common;
4207
4208       if (comp_target_types (colon_loc, type1, type2))
4209         result_type = common_pointer_type (type1, type2);
4210       else if (null_pointer_constant_p (orig_op1))
4211         result_type = type2;
4212       else if (null_pointer_constant_p (orig_op2))
4213         result_type = type1;
4214       else if (!addr_space_superset (as1, as2, &as_common))
4215         {
4216           error_at (colon_loc, "pointers to disjoint address spaces "
4217                     "used in conditional expression");
4218           return error_mark_node;
4219         }
4220       else if (VOID_TYPE_P (TREE_TYPE (type1)))
4221         {
4222           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
4223             pedwarn (colon_loc, OPT_pedantic,
4224                      "ISO C forbids conditional expr between "
4225                      "%<void *%> and function pointer");
4226           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
4227                                                           TREE_TYPE (type2)));
4228         }
4229       else if (VOID_TYPE_P (TREE_TYPE (type2)))
4230         {
4231           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
4232             pedwarn (colon_loc, OPT_pedantic,
4233                      "ISO C forbids conditional expr between "
4234                      "%<void *%> and function pointer");
4235           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
4236                                                           TREE_TYPE (type1)));
4237         }
4238       /* Objective-C pointer comparisons are a bit more lenient.  */
4239       else if (objc_have_common_type (type1, type2, -3, NULL_TREE))
4240         result_type = objc_common_type (type1, type2);
4241       else
4242         {
4243           int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
4244
4245           pedwarn (colon_loc, 0,
4246                    "pointer type mismatch in conditional expression");
4247           result_type = build_pointer_type
4248                           (build_qualified_type (void_type_node, qual));
4249         }
4250     }
4251   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
4252     {
4253       if (!null_pointer_constant_p (orig_op2))
4254         pedwarn (colon_loc, 0,
4255                  "pointer/integer type mismatch in conditional expression");
4256       else
4257         {
4258           op2 = null_pointer_node;
4259         }
4260       result_type = type1;
4261     }
4262   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
4263     {
4264       if (!null_pointer_constant_p (orig_op1))
4265         pedwarn (colon_loc, 0,
4266                  "pointer/integer type mismatch in conditional expression");
4267       else
4268         {
4269           op1 = null_pointer_node;
4270         }
4271       result_type = type2;
4272     }
4273
4274   if (!result_type)
4275     {
4276       if (flag_cond_mismatch)
4277         result_type = void_type_node;
4278       else
4279         {
4280           error_at (colon_loc, "type mismatch in conditional expression");
4281           return error_mark_node;
4282         }
4283     }
4284
4285   /* Merge const and volatile flags of the incoming types.  */
4286   result_type
4287     = build_type_variant (result_type,
4288                           TYPE_READONLY (type1) || TYPE_READONLY (type2),
4289                           TYPE_VOLATILE (type1) || TYPE_VOLATILE (type2));
4290
4291   op1 = ep_convert_and_check (result_type, op1, semantic_result_type);
4292   op2 = ep_convert_and_check (result_type, op2, semantic_result_type);
4293
4294   if (ifexp_bcp && ifexp == truthvalue_true_node)
4295     {
4296       op2_int_operands = true;
4297       op1 = c_fully_fold (op1, require_constant_value, NULL);
4298     }
4299   if (ifexp_bcp && ifexp == truthvalue_false_node)
4300     {
4301       op1_int_operands = true;
4302       op2 = c_fully_fold (op2, require_constant_value, NULL);
4303     }
4304   int_const = int_operands = (ifexp_int_operands
4305                               && op1_int_operands
4306                               && op2_int_operands);
4307   if (int_operands)
4308     {
4309       int_const = ((ifexp == truthvalue_true_node
4310                     && TREE_CODE (orig_op1) == INTEGER_CST
4311                     && !TREE_OVERFLOW (orig_op1))
4312                    || (ifexp == truthvalue_false_node
4313                        && TREE_CODE (orig_op2) == INTEGER_CST
4314                        && !TREE_OVERFLOW (orig_op2)));
4315     }
4316   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
4317     ret = fold_build3_loc (colon_loc, COND_EXPR, result_type, ifexp, op1, op2);
4318   else
4319     {
4320       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
4321       if (int_operands)
4322         ret = note_integer_operands (ret);
4323     }
4324   if (semantic_result_type)
4325     ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
4326
4327   protected_set_expr_location (ret, colon_loc);
4328   return ret;
4329 }
4330 \f
4331 /* Return a compound expression that performs two expressions and
4332    returns the value of the second of them.
4333
4334    LOC is the location of the COMPOUND_EXPR.  */
4335
4336 tree
4337 build_compound_expr (location_t loc, tree expr1, tree expr2)
4338 {
4339   bool expr1_int_operands, expr2_int_operands;
4340   tree eptype = NULL_TREE;
4341   tree ret;
4342
4343   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4344   if (expr1_int_operands)
4345     expr1 = remove_c_maybe_const_expr (expr1);
4346   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4347   if (expr2_int_operands)
4348     expr2 = remove_c_maybe_const_expr (expr2);
4349
4350   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4351     expr1 = TREE_OPERAND (expr1, 0);
4352   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4353     {
4354       eptype = TREE_TYPE (expr2);
4355       expr2 = TREE_OPERAND (expr2, 0);
4356     }
4357
4358   if (!TREE_SIDE_EFFECTS (expr1))
4359     {
4360       /* The left-hand operand of a comma expression is like an expression
4361          statement: with -Wunused, we should warn if it doesn't have
4362          any side-effects, unless it was explicitly cast to (void).  */
4363       if (warn_unused_value)
4364         {
4365           if (VOID_TYPE_P (TREE_TYPE (expr1))
4366               && CONVERT_EXPR_P (expr1))
4367             ; /* (void) a, b */
4368           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4369                    && TREE_CODE (expr1) == COMPOUND_EXPR
4370                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4371             ; /* (void) a, (void) b, c */
4372           else
4373             warning_at (loc, OPT_Wunused_value,
4374                         "left-hand operand of comma expression has no effect");
4375         }
4376     }
4377
4378   /* With -Wunused, we should also warn if the left-hand operand does have
4379      side-effects, but computes a value which is not used.  For example, in
4380      `foo() + bar(), baz()' the result of the `+' operator is not used,
4381      so we should issue a warning.  */
4382   else if (warn_unused_value)
4383     warn_if_unused_value (expr1, loc);
4384
4385   if (expr2 == error_mark_node)
4386     return error_mark_node;
4387
4388   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4389
4390   if (flag_isoc99
4391       && expr1_int_operands
4392       && expr2_int_operands)
4393     ret = note_integer_operands (ret);
4394
4395   if (eptype)
4396     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4397
4398   protected_set_expr_location (ret, loc);
4399   return ret;
4400 }
4401
4402 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4403    which we are casting.  OTYPE is the type of the expression being
4404    cast.  Both TYPE and OTYPE are pointer types.  LOC is the location
4405    of the cast.  -Wcast-qual appeared on the command line.  Named
4406    address space qualifiers are not handled here, because they result
4407    in different warnings.  */
4408
4409 static void
4410 handle_warn_cast_qual (location_t loc, tree type, tree otype)
4411 {
4412   tree in_type = type;
4413   tree in_otype = otype;
4414   int added = 0;
4415   int discarded = 0;
4416   bool is_const;
4417
4418   /* Check that the qualifiers on IN_TYPE are a superset of the
4419      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4420      nodes is uninteresting and we stop as soon as we hit a
4421      non-POINTER_TYPE node on either type.  */
4422   do
4423     {
4424       in_otype = TREE_TYPE (in_otype);
4425       in_type = TREE_TYPE (in_type);
4426
4427       /* GNU C allows cv-qualified function types.  'const' means the
4428          function is very pure, 'volatile' means it can't return.  We
4429          need to warn when such qualifiers are added, not when they're
4430          taken away.  */
4431       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4432           && TREE_CODE (in_type) == FUNCTION_TYPE)
4433         added |= (TYPE_QUALS_NO_ADDR_SPACE (in_type)
4434                   & ~TYPE_QUALS_NO_ADDR_SPACE (in_otype));
4435       else
4436         discarded |= (TYPE_QUALS_NO_ADDR_SPACE (in_otype)
4437                       & ~TYPE_QUALS_NO_ADDR_SPACE (in_type));
4438     }
4439   while (TREE_CODE (in_type) == POINTER_TYPE
4440          && TREE_CODE (in_otype) == POINTER_TYPE);
4441
4442   if (added)
4443     warning_at (loc, OPT_Wcast_qual,
4444                 "cast adds %q#v qualifier to function type", added);
4445
4446   if (discarded)
4447     /* There are qualifiers present in IN_OTYPE that are not present
4448        in IN_TYPE.  */
4449     warning_at (loc, OPT_Wcast_qual,
4450                 "cast discards %q#v qualifier from pointer target type",
4451                 discarded);
4452
4453   if (added || discarded)
4454     return;
4455
4456   /* A cast from **T to const **T is unsafe, because it can cause a
4457      const value to be changed with no additional warning.  We only
4458      issue this warning if T is the same on both sides, and we only
4459      issue the warning if there are the same number of pointers on
4460      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4461      cast is unsafe when a qualifier is added at one level and const
4462      is not present at all outer levels.
4463
4464      To issue this warning, we check at each level whether the cast
4465      adds new qualifiers not already seen.  We don't need to special
4466      case function types, as they won't have the same
4467      TYPE_MAIN_VARIANT.  */
4468
4469   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4470     return;
4471   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4472     return;
4473
4474   in_type = type;
4475   in_otype = otype;
4476   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4477   do
4478     {
4479       in_type = TREE_TYPE (in_type);
4480       in_otype = TREE_TYPE (in_otype);
4481       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4482           && !is_const)
4483         {
4484           warning_at (loc, OPT_Wcast_qual,
4485                       "to be safe all intermediate pointers in cast from "
4486                       "%qT to %qT must be %<const%> qualified",
4487                       otype, type);
4488           break;
4489         }
4490       if (is_const)
4491         is_const = TYPE_READONLY (in_type);
4492     }
4493   while (TREE_CODE (in_type) == POINTER_TYPE);
4494 }
4495
4496 /* Build an expression representing a cast to type TYPE of expression EXPR.
4497    LOC is the location of the cast-- typically the open paren of the cast.  */
4498
4499 tree
4500 build_c_cast (location_t loc, tree type, tree expr)
4501 {
4502   tree value;
4503
4504   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4505     expr = TREE_OPERAND (expr, 0);
4506
4507   value = expr;
4508
4509   if (type == error_mark_node || expr == error_mark_node)
4510     return error_mark_node;
4511
4512   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4513      only in <protocol> qualifications.  But when constructing cast expressions,
4514      the protocols do matter and must be kept around.  */
4515   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4516     return build1 (NOP_EXPR, type, expr);
4517
4518   type = TYPE_MAIN_VARIANT (type);
4519
4520   if (TREE_CODE (type) == ARRAY_TYPE)
4521     {
4522       error_at (loc, "cast specifies array type");
4523       return error_mark_node;
4524     }
4525
4526   if (TREE_CODE (type) == FUNCTION_TYPE)
4527     {
4528       error_at (loc, "cast specifies function type");
4529       return error_mark_node;
4530     }
4531
4532   if (!VOID_TYPE_P (type))
4533     {
4534       value = require_complete_type (value);
4535       if (value == error_mark_node)
4536         return error_mark_node;
4537     }
4538
4539   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4540     {
4541       if (TREE_CODE (type) == RECORD_TYPE
4542           || TREE_CODE (type) == UNION_TYPE)
4543         pedwarn (loc, OPT_pedantic,
4544                  "ISO C forbids casting nonscalar to the same type");
4545     }
4546   else if (TREE_CODE (type) == UNION_TYPE)
4547     {
4548       tree field;
4549
4550       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
4551         if (TREE_TYPE (field) != error_mark_node
4552             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4553                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4554           break;
4555
4556       if (field)
4557         {
4558           tree t;
4559           bool maybe_const = true;
4560
4561           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4562           t = c_fully_fold (value, false, &maybe_const);
4563           t = build_constructor_single (type, field, t);
4564           if (!maybe_const)
4565             t = c_wrap_maybe_const (t, true);
4566           t = digest_init (loc, type, t,
4567                            NULL_TREE, false, true, 0);
4568           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4569           return t;
4570         }
4571       error_at (loc, "cast to union type from type not present in union");
4572       return error_mark_node;
4573     }
4574   else
4575     {
4576       tree otype, ovalue;
4577
4578       if (type == void_type_node)
4579         {
4580           tree t = build1 (CONVERT_EXPR, type, value);
4581           SET_EXPR_LOCATION (t, loc);
4582           return t;
4583         }
4584
4585       otype = TREE_TYPE (value);
4586
4587       /* Optionally warn about potentially worrisome casts.  */
4588       if (warn_cast_qual
4589           && TREE_CODE (type) == POINTER_TYPE
4590           && TREE_CODE (otype) == POINTER_TYPE)
4591         handle_warn_cast_qual (loc, type, otype);
4592
4593       /* Warn about conversions between pointers to disjoint
4594          address spaces.  */
4595       if (TREE_CODE (type) == POINTER_TYPE
4596           && TREE_CODE (otype) == POINTER_TYPE
4597           && !null_pointer_constant_p (value))
4598         {
4599           addr_space_t as_to = TYPE_ADDR_SPACE (TREE_TYPE (type));
4600           addr_space_t as_from = TYPE_ADDR_SPACE (TREE_TYPE (otype));
4601           addr_space_t as_common;
4602
4603           if (!addr_space_superset (as_to, as_from, &as_common))
4604             {
4605               if (ADDR_SPACE_GENERIC_P (as_from))
4606                 warning_at (loc, 0, "cast to %s address space pointer "
4607                             "from disjoint generic address space pointer",
4608                             c_addr_space_name (as_to));
4609
4610               else if (ADDR_SPACE_GENERIC_P (as_to))
4611                 warning_at (loc, 0, "cast to generic address space pointer "
4612                             "from disjoint %s address space pointer",
4613                             c_addr_space_name (as_from));
4614
4615               else
4616                 warning_at (loc, 0, "cast to %s address space pointer "
4617                             "from disjoint %s address space pointer",
4618                             c_addr_space_name (as_to),
4619                             c_addr_space_name (as_from));
4620             }
4621         }
4622
4623       /* Warn about possible alignment problems.  */
4624       if (STRICT_ALIGNMENT
4625           && TREE_CODE (type) == POINTER_TYPE
4626           && TREE_CODE (otype) == POINTER_TYPE
4627           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4628           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4629           /* Don't warn about opaque types, where the actual alignment
4630              restriction is unknown.  */
4631           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4632                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4633                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4634           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4635         warning_at (loc, OPT_Wcast_align,
4636                     "cast increases required alignment of target type");
4637
4638       if (TREE_CODE (type) == INTEGER_TYPE
4639           && TREE_CODE (otype) == POINTER_TYPE
4640           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4641       /* Unlike conversion of integers to pointers, where the
4642          warning is disabled for converting constants because
4643          of cases such as SIG_*, warn about converting constant
4644          pointers to integers. In some cases it may cause unwanted
4645          sign extension, and a warning is appropriate.  */
4646         warning_at (loc, OPT_Wpointer_to_int_cast,
4647                     "cast from pointer to integer of different size");
4648
4649       if (TREE_CODE (value) == CALL_EXPR
4650           && TREE_CODE (type) != TREE_CODE (otype))
4651         warning_at (loc, OPT_Wbad_function_cast,
4652                     "cast from function call of type %qT "
4653                     "to non-matching type %qT", otype, type);
4654
4655       if (TREE_CODE (type) == POINTER_TYPE
4656           && TREE_CODE (otype) == INTEGER_TYPE
4657           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4658           /* Don't warn about converting any constant.  */
4659           && !TREE_CONSTANT (value))
4660         warning_at (loc,
4661                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4662                     "of different size");
4663
4664       if (warn_strict_aliasing <= 2)
4665         strict_aliasing_warning (otype, type, expr);
4666
4667       /* If pedantic, warn for conversions between function and object
4668          pointer types, except for converting a null pointer constant
4669          to function pointer type.  */
4670       if (pedantic
4671           && TREE_CODE (type) == POINTER_TYPE
4672           && TREE_CODE (otype) == POINTER_TYPE
4673           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4674           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4675         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4676                  "conversion of function pointer to object pointer type");
4677
4678       if (pedantic
4679           && TREE_CODE (type) == POINTER_TYPE
4680           && TREE_CODE (otype) == POINTER_TYPE
4681           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4682           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4683           && !null_pointer_constant_p (value))
4684         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4685                  "conversion of object pointer to function pointer type");
4686
4687       ovalue = value;
4688       value = convert (type, value);
4689
4690       /* Ignore any integer overflow caused by the cast.  */
4691       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4692         {
4693           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4694             {
4695               if (!TREE_OVERFLOW (value))
4696                 {
4697                   /* Avoid clobbering a shared constant.  */
4698                   value = copy_node (value);
4699                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4700                 }
4701             }
4702           else if (TREE_OVERFLOW (value))
4703             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4704             value = build_int_cst_wide (TREE_TYPE (value),
4705                                         TREE_INT_CST_LOW (value),
4706                                         TREE_INT_CST_HIGH (value));
4707         }
4708     }
4709
4710   /* Don't let a cast be an lvalue.  */
4711   if (value == expr)
4712     value = non_lvalue_loc (loc, value);
4713
4714   /* Don't allow the results of casting to floating-point or complex
4715      types be confused with actual constants, or casts involving
4716      integer and pointer types other than direct integer-to-integer
4717      and integer-to-pointer be confused with integer constant
4718      expressions and null pointer constants.  */
4719   if (TREE_CODE (value) == REAL_CST
4720       || TREE_CODE (value) == COMPLEX_CST
4721       || (TREE_CODE (value) == INTEGER_CST
4722           && !((TREE_CODE (expr) == INTEGER_CST
4723                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4724                || TREE_CODE (expr) == REAL_CST
4725                || TREE_CODE (expr) == COMPLEX_CST)))
4726       value = build1 (NOP_EXPR, type, value);
4727
4728   if (CAN_HAVE_LOCATION_P (value))
4729     SET_EXPR_LOCATION (value, loc);
4730   return value;
4731 }
4732
4733 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4734    location of the open paren of the cast, or the position of the cast
4735    expr.  */
4736 tree
4737 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4738 {
4739   tree type;
4740   tree type_expr = NULL_TREE;
4741   bool type_expr_const = true;
4742   tree ret;
4743   int saved_wsp = warn_strict_prototypes;
4744
4745   /* This avoids warnings about unprototyped casts on
4746      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4747   if (TREE_CODE (expr) == INTEGER_CST)
4748     warn_strict_prototypes = 0;
4749   type = groktypename (type_name, &type_expr, &type_expr_const);
4750   warn_strict_prototypes = saved_wsp;
4751
4752   ret = build_c_cast (loc, type, expr);
4753   if (type_expr)
4754     {
4755       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4756       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4757       SET_EXPR_LOCATION (ret, loc);
4758     }
4759
4760   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4761     SET_EXPR_LOCATION (ret, loc);
4762
4763   /* C++ does not permits types to be defined in a cast, but it
4764      allows references to incomplete types.  */
4765   if (warn_cxx_compat && type_name->specs->typespec_kind == ctsk_tagdef)
4766     warning_at (loc, OPT_Wc___compat,
4767                 "defining a type in a cast is invalid in C++");
4768
4769   return ret;
4770 }
4771 \f
4772 /* Build an assignment expression of lvalue LHS from value RHS.
4773    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4774    may differ from TREE_TYPE (LHS) for an enum bitfield.
4775    MODIFYCODE is the code for a binary operator that we use
4776    to combine the old value of LHS with RHS to get the new value.
4777    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4778    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4779    which may differ from TREE_TYPE (RHS) for an enum value.
4780
4781    LOCATION is the location of the MODIFYCODE operator.
4782    RHS_LOC is the location of the RHS.  */
4783
4784 tree
4785 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4786                    enum tree_code modifycode,
4787                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4788 {
4789   tree result;
4790   tree newrhs;
4791   tree rhs_semantic_type = NULL_TREE;
4792   tree lhstype = TREE_TYPE (lhs);
4793   tree olhstype = lhstype;
4794   bool npc;
4795
4796   /* Types that aren't fully specified cannot be used in assignments.  */
4797   lhs = require_complete_type (lhs);
4798
4799   /* Avoid duplicate error messages from operands that had errors.  */
4800   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4801     return error_mark_node;
4802
4803   /* For ObjC properties, defer this check.  */
4804   if (!objc_is_property_ref (lhs) && !lvalue_or_else (lhs, lv_assign))
4805     return error_mark_node;
4806
4807   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4808     {
4809       rhs_semantic_type = TREE_TYPE (rhs);
4810       rhs = TREE_OPERAND (rhs, 0);
4811     }
4812
4813   newrhs = rhs;
4814
4815   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4816     {
4817       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4818                                       lhs_origtype, modifycode, rhs_loc, rhs,
4819                                       rhs_origtype);
4820       if (inner == error_mark_node)
4821         return error_mark_node;
4822       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4823                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4824       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4825       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4826       protected_set_expr_location (result, location);
4827       return result;
4828     }
4829
4830   /* If a binary op has been requested, combine the old LHS value with the RHS
4831      producing the value we should actually store into the LHS.  */
4832
4833   if (modifycode != NOP_EXPR)
4834     {
4835       lhs = c_fully_fold (lhs, false, NULL);
4836       lhs = stabilize_reference (lhs);
4837       newrhs = build_binary_op (location,
4838                                 modifycode, lhs, rhs, 1);
4839
4840       /* The original type of the right hand side is no longer
4841          meaningful.  */
4842       rhs_origtype = NULL_TREE;
4843     }
4844
4845   if (c_dialect_objc ())
4846     {
4847       /* Check if we are modifying an Objective-C property reference;
4848          if so, we need to generate setter calls.  */
4849       result = objc_maybe_build_modify_expr (lhs, newrhs);
4850       if (result)
4851         return result;
4852
4853       /* Else, do the check that we postponed for Objective-C.  */
4854       if (!lvalue_or_else (lhs, lv_assign))
4855         return error_mark_node;
4856     }
4857
4858   /* Give an error for storing in something that is 'const'.  */
4859
4860   if (TYPE_READONLY (lhstype)
4861       || ((TREE_CODE (lhstype) == RECORD_TYPE
4862            || TREE_CODE (lhstype) == UNION_TYPE)
4863           && C_TYPE_FIELDS_READONLY (lhstype)))
4864     {
4865       readonly_error (lhs, lv_assign);
4866       return error_mark_node;
4867     }
4868   else if (TREE_READONLY (lhs))
4869     readonly_warning (lhs, lv_assign);
4870
4871   /* If storing into a structure or union member,
4872      it has probably been given type `int'.
4873      Compute the type that would go with
4874      the actual amount of storage the member occupies.  */
4875
4876   if (TREE_CODE (lhs) == COMPONENT_REF
4877       && (TREE_CODE (lhstype) == INTEGER_TYPE
4878           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4879           || TREE_CODE (lhstype) == REAL_TYPE
4880           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4881     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4882
4883   /* If storing in a field that is in actuality a short or narrower than one,
4884      we must store in the field in its actual type.  */
4885
4886   if (lhstype != TREE_TYPE (lhs))
4887     {
4888       lhs = copy_node (lhs);
4889       TREE_TYPE (lhs) = lhstype;
4890     }
4891
4892   /* Issue -Wc++-compat warnings about an assignment to an enum type
4893      when LHS does not have its original type.  This happens for,
4894      e.g., an enum bitfield in a struct.  */
4895   if (warn_cxx_compat
4896       && lhs_origtype != NULL_TREE
4897       && lhs_origtype != lhstype
4898       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4899     {
4900       tree checktype = (rhs_origtype != NULL_TREE
4901                         ? rhs_origtype
4902                         : TREE_TYPE (rhs));
4903       if (checktype != error_mark_node
4904           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4905         warning_at (location, OPT_Wc___compat,
4906                     "enum conversion in assignment is invalid in C++");
4907     }
4908
4909   /* Convert new value to destination type.  Fold it first, then
4910      restore any excess precision information, for the sake of
4911      conversion warnings.  */
4912
4913   npc = null_pointer_constant_p (newrhs);
4914   newrhs = c_fully_fold (newrhs, false, NULL);
4915   if (rhs_semantic_type)
4916     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4917   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4918                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4919   if (TREE_CODE (newrhs) == ERROR_MARK)
4920     return error_mark_node;
4921
4922   /* Emit ObjC write barrier, if necessary.  */
4923   if (c_dialect_objc () && flag_objc_gc)
4924     {
4925       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4926       if (result)
4927         {
4928           protected_set_expr_location (result, location);
4929           return result;
4930         }
4931     }
4932
4933   /* Scan operands.  */
4934
4935   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4936   TREE_SIDE_EFFECTS (result) = 1;
4937   protected_set_expr_location (result, location);
4938
4939   /* If we got the LHS in a different type for storing in,
4940      convert the result back to the nominal type of LHS
4941      so that the value we return always has the same type
4942      as the LHS argument.  */
4943
4944   if (olhstype == TREE_TYPE (result))
4945     return result;
4946
4947   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
4948                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
4949   protected_set_expr_location (result, location);
4950   return result;
4951 }
4952 \f
4953 /* Return whether STRUCT_TYPE has an anonymous field with type TYPE.
4954    This is used to implement -fplan9-extensions.  */
4955
4956 static bool
4957 find_anonymous_field_with_type (tree struct_type, tree type)
4958 {
4959   tree field;
4960   bool found;
4961
4962   gcc_assert (TREE_CODE (struct_type) == RECORD_TYPE
4963               || TREE_CODE (struct_type) == UNION_TYPE);
4964   found = false;
4965   for (field = TYPE_FIELDS (struct_type);
4966        field != NULL_TREE;
4967        field = TREE_CHAIN (field))
4968     {
4969       if (DECL_NAME (field) == NULL
4970           && comptypes (type, TYPE_MAIN_VARIANT (TREE_TYPE (field))))
4971         {
4972           if (found)
4973             return false;
4974           found = true;
4975         }
4976       else if (DECL_NAME (field) == NULL
4977                && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
4978                    || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4979                && find_anonymous_field_with_type (TREE_TYPE (field), type))
4980         {
4981           if (found)
4982             return false;
4983           found = true;
4984         }
4985     }
4986   return found;
4987 }
4988
4989 /* RHS is an expression whose type is pointer to struct.  If there is
4990    an anonymous field in RHS with type TYPE, then return a pointer to
4991    that field in RHS.  This is used with -fplan9-extensions.  This
4992    returns NULL if no conversion could be found.  */
4993
4994 static tree
4995 convert_to_anonymous_field (location_t location, tree type, tree rhs)
4996 {
4997   tree rhs_struct_type, lhs_main_type;
4998   tree field, found_field;
4999   bool found_sub_field;
5000   tree ret;
5001
5002   gcc_assert (POINTER_TYPE_P (TREE_TYPE (rhs)));
5003   rhs_struct_type = TREE_TYPE (TREE_TYPE (rhs));
5004   gcc_assert (TREE_CODE (rhs_struct_type) == RECORD_TYPE
5005               || TREE_CODE (rhs_struct_type) == UNION_TYPE);
5006
5007   gcc_assert (POINTER_TYPE_P (type));
5008   lhs_main_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5009
5010   found_field = NULL_TREE;
5011   found_sub_field = false;
5012   for (field = TYPE_FIELDS (rhs_struct_type);
5013        field != NULL_TREE;
5014        field = TREE_CHAIN (field))
5015     {
5016       if (DECL_NAME (field) != NULL_TREE
5017           || (TREE_CODE (TREE_TYPE (field)) != RECORD_TYPE
5018               && TREE_CODE (TREE_TYPE (field)) != UNION_TYPE))
5019         continue;
5020       if (comptypes (lhs_main_type, TYPE_MAIN_VARIANT (TREE_TYPE (field))))
5021         {
5022           if (found_field != NULL_TREE)
5023             return NULL_TREE;
5024           found_field = field;
5025         }
5026       else if (find_anonymous_field_with_type (TREE_TYPE (field),
5027                                                lhs_main_type))
5028         {
5029           if (found_field != NULL_TREE)
5030             return NULL_TREE;
5031           found_field = field;
5032           found_sub_field = true;
5033         }
5034     }
5035
5036   if (found_field == NULL_TREE)
5037     return NULL_TREE;
5038
5039   ret = fold_build3_loc (location, COMPONENT_REF, TREE_TYPE (found_field),
5040                          build_fold_indirect_ref (rhs), found_field,
5041                          NULL_TREE);
5042   ret = build_fold_addr_expr_loc (location, ret);
5043
5044   if (found_sub_field)
5045     {
5046       ret = convert_to_anonymous_field (location, type, ret);
5047       gcc_assert (ret != NULL_TREE);
5048     }
5049
5050   return ret;
5051 }
5052
5053 /* Convert value RHS to type TYPE as preparation for an assignment to
5054    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
5055    original type of RHS; this differs from TREE_TYPE (RHS) for enum
5056    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
5057    constant before any folding.
5058    The real work of conversion is done by `convert'.
5059    The purpose of this function is to generate error messages
5060    for assignments that are not allowed in C.
5061    ERRTYPE says whether it is argument passing, assignment,
5062    initialization or return.
5063
5064    LOCATION is the location of the RHS.
5065    FUNCTION is a tree for the function being called.
5066    PARMNUM is the number of the argument, for printing in error messages.  */
5067
5068 static tree
5069 convert_for_assignment (location_t location, tree type, tree rhs,
5070                         tree origtype, enum impl_conv errtype,
5071                         bool null_pointer_constant, tree fundecl,
5072                         tree function, int parmnum)
5073 {
5074   enum tree_code codel = TREE_CODE (type);
5075   tree orig_rhs = rhs;
5076   tree rhstype;
5077   enum tree_code coder;
5078   tree rname = NULL_TREE;
5079   bool objc_ok = false;
5080
5081   if (errtype == ic_argpass)
5082     {
5083       tree selector;
5084       /* Change pointer to function to the function itself for
5085          diagnostics.  */
5086       if (TREE_CODE (function) == ADDR_EXPR
5087           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
5088         function = TREE_OPERAND (function, 0);
5089
5090       /* Handle an ObjC selector specially for diagnostics.  */
5091       selector = objc_message_selector ();
5092       rname = function;
5093       if (selector && parmnum > 2)
5094         {
5095           rname = selector;
5096           parmnum -= 2;
5097         }
5098     }
5099
5100   /* This macro is used to emit diagnostics to ensure that all format
5101      strings are complete sentences, visible to gettext and checked at
5102      compile time.  */
5103 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
5104   do {                                                                   \
5105     switch (errtype)                                                     \
5106       {                                                                  \
5107       case ic_argpass:                                                   \
5108         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
5109           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
5110                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
5111                   "expected %qT but argument is of type %qT",            \
5112                   type, rhstype);                                        \
5113         break;                                                           \
5114       case ic_assign:                                                    \
5115         pedwarn (LOCATION, OPT, AS);                                     \
5116         break;                                                           \
5117       case ic_init:                                                      \
5118         pedwarn_init (LOCATION, OPT, IN);                                \
5119         break;                                                           \
5120       case ic_return:                                                    \
5121         pedwarn (LOCATION, OPT, RE);                                     \
5122         break;                                                           \
5123       default:                                                           \
5124         gcc_unreachable ();                                              \
5125       }                                                                  \
5126   } while (0)
5127
5128   /* This macro is used to emit diagnostics to ensure that all format
5129      strings are complete sentences, visible to gettext and checked at
5130      compile time.  It is the same as WARN_FOR_ASSIGNMENT but with an
5131      extra parameter to enumerate qualifiers.  */
5132
5133 #define WARN_FOR_QUALIFIERS(LOCATION, OPT, AR, AS, IN, RE, QUALS)        \
5134   do {                                                                   \
5135     switch (errtype)                                                     \
5136       {                                                                  \
5137       case ic_argpass:                                                   \
5138         if (pedwarn (LOCATION, OPT, AR, parmnum, rname, QUALS))          \
5139           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
5140                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
5141                   "expected %qT but argument is of type %qT",            \
5142                   type, rhstype);                                        \
5143         break;                                                           \
5144       case ic_assign:                                                    \
5145         pedwarn (LOCATION, OPT, AS, QUALS);                          \
5146         break;                                                           \
5147       case ic_init:                                                      \
5148         pedwarn (LOCATION, OPT, IN, QUALS);                          \
5149         break;                                                           \
5150       case ic_return:                                                    \
5151         pedwarn (LOCATION, OPT, RE, QUALS);                              \
5152         break;                                                           \
5153       default:                                                           \
5154         gcc_unreachable ();                                              \
5155       }                                                                  \
5156   } while (0)
5157
5158   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
5159     rhs = TREE_OPERAND (rhs, 0);
5160
5161   rhstype = TREE_TYPE (rhs);
5162   coder = TREE_CODE (rhstype);
5163
5164   if (coder == ERROR_MARK)
5165     return error_mark_node;
5166
5167   if (c_dialect_objc ())
5168     {
5169       int parmno;
5170
5171       switch (errtype)
5172         {
5173         case ic_return:
5174           parmno = 0;
5175           break;
5176
5177         case ic_assign:
5178           parmno = -1;
5179           break;
5180
5181         case ic_init:
5182           parmno = -2;
5183           break;
5184
5185         default:
5186           parmno = parmnum;
5187           break;
5188         }
5189
5190       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
5191     }
5192
5193   if (warn_cxx_compat)
5194     {
5195       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
5196       if (checktype != error_mark_node
5197           && TREE_CODE (type) == ENUMERAL_TYPE
5198           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
5199         {
5200           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
5201                                G_("enum conversion when passing argument "
5202                                   "%d of %qE is invalid in C++"),
5203                                G_("enum conversion in assignment is "
5204                                   "invalid in C++"),
5205                                G_("enum conversion in initialization is "
5206                                   "invalid in C++"),
5207                                G_("enum conversion in return is "
5208                                   "invalid in C++"));
5209         }
5210     }
5211
5212   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
5213     return rhs;
5214
5215   if (coder == VOID_TYPE)
5216     {
5217       /* Except for passing an argument to an unprototyped function,
5218          this is a constraint violation.  When passing an argument to
5219          an unprototyped function, it is compile-time undefined;
5220          making it a constraint in that case was rejected in
5221          DR#252.  */
5222       error_at (location, "void value not ignored as it ought to be");
5223       return error_mark_node;
5224     }
5225   rhs = require_complete_type (rhs);
5226   if (rhs == error_mark_node)
5227     return error_mark_node;
5228   /* A type converts to a reference to it.
5229      This code doesn't fully support references, it's just for the
5230      special case of va_start and va_copy.  */
5231   if (codel == REFERENCE_TYPE
5232       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
5233     {
5234       if (!lvalue_p (rhs))
5235         {
5236           error_at (location, "cannot pass rvalue to reference parameter");
5237           return error_mark_node;
5238         }
5239       if (!c_mark_addressable (rhs))
5240         return error_mark_node;
5241       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
5242       SET_EXPR_LOCATION (rhs, location);
5243
5244       /* We already know that these two types are compatible, but they
5245          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
5246          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
5247          likely to be va_list, a typedef to __builtin_va_list, which
5248          is different enough that it will cause problems later.  */
5249       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
5250         {
5251           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
5252           SET_EXPR_LOCATION (rhs, location);
5253         }
5254
5255       rhs = build1 (NOP_EXPR, type, rhs);
5256       SET_EXPR_LOCATION (rhs, location);
5257       return rhs;
5258     }
5259   /* Some types can interconvert without explicit casts.  */
5260   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
5261            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
5262     return convert (type, rhs);
5263   /* Arithmetic types all interconvert, and enum is treated like int.  */
5264   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
5265             || codel == FIXED_POINT_TYPE
5266             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
5267             || codel == BOOLEAN_TYPE)
5268            && (coder == INTEGER_TYPE || coder == REAL_TYPE
5269                || coder == FIXED_POINT_TYPE
5270                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
5271                || coder == BOOLEAN_TYPE))
5272     {
5273       tree ret;
5274       bool save = in_late_binary_op;
5275       if (codel == BOOLEAN_TYPE)
5276         in_late_binary_op = true;
5277       ret = convert_and_check (type, orig_rhs);
5278       if (codel == BOOLEAN_TYPE)
5279         in_late_binary_op = save;
5280       return ret;
5281     }
5282
5283   /* Aggregates in different TUs might need conversion.  */
5284   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
5285       && codel == coder
5286       && comptypes (type, rhstype))
5287     return convert_and_check (type, rhs);
5288
5289   /* Conversion to a transparent union or record from its member types.
5290      This applies only to function arguments.  */
5291   if (((codel == UNION_TYPE || codel == RECORD_TYPE)
5292       && TYPE_TRANSPARENT_AGGR (type))
5293       && errtype == ic_argpass)
5294     {
5295       tree memb, marginal_memb = NULL_TREE;
5296
5297       for (memb = TYPE_FIELDS (type); memb ; memb = DECL_CHAIN (memb))
5298         {
5299           tree memb_type = TREE_TYPE (memb);
5300
5301           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
5302                          TYPE_MAIN_VARIANT (rhstype)))
5303             break;
5304
5305           if (TREE_CODE (memb_type) != POINTER_TYPE)
5306             continue;
5307
5308           if (coder == POINTER_TYPE)
5309             {
5310               tree ttl = TREE_TYPE (memb_type);
5311               tree ttr = TREE_TYPE (rhstype);
5312
5313               /* Any non-function converts to a [const][volatile] void *
5314                  and vice versa; otherwise, targets must be the same.
5315                  Meanwhile, the lhs target must have all the qualifiers of
5316                  the rhs.  */
5317               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5318                   || comp_target_types (location, memb_type, rhstype))
5319                 {
5320                   /* If this type won't generate any warnings, use it.  */
5321                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
5322                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
5323                            && TREE_CODE (ttl) == FUNCTION_TYPE)
5324                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5325                              == TYPE_QUALS (ttr))
5326                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5327                              == TYPE_QUALS (ttl))))
5328                     break;
5329
5330                   /* Keep looking for a better type, but remember this one.  */
5331                   if (!marginal_memb)
5332                     marginal_memb = memb;
5333                 }
5334             }
5335
5336           /* Can convert integer zero to any pointer type.  */
5337           if (null_pointer_constant)
5338             {
5339               rhs = null_pointer_node;
5340               break;
5341             }
5342         }
5343
5344       if (memb || marginal_memb)
5345         {
5346           if (!memb)
5347             {
5348               /* We have only a marginally acceptable member type;
5349                  it needs a warning.  */
5350               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
5351               tree ttr = TREE_TYPE (rhstype);
5352
5353               /* Const and volatile mean something different for function
5354                  types, so the usual warnings are not appropriate.  */
5355               if (TREE_CODE (ttr) == FUNCTION_TYPE
5356                   && TREE_CODE (ttl) == FUNCTION_TYPE)
5357                 {
5358                   /* Because const and volatile on functions are
5359                      restrictions that say the function will not do
5360                      certain things, it is okay to use a const or volatile
5361                      function where an ordinary one is wanted, but not
5362                      vice-versa.  */
5363                   if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5364                       & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5365                     WARN_FOR_QUALIFIERS (location, 0,
5366                                          G_("passing argument %d of %qE "
5367                                             "makes %q#v qualified function "
5368                                             "pointer from unqualified"),
5369                                          G_("assignment makes %q#v qualified "
5370                                             "function pointer from "
5371                                             "unqualified"),
5372                                          G_("initialization makes %q#v qualified "
5373                                             "function pointer from "
5374                                             "unqualified"),
5375                                          G_("return makes %q#v qualified function "
5376                                             "pointer from unqualified"),
5377                                          TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr));
5378                 }
5379               else if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5380                        & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5381                 WARN_FOR_QUALIFIERS (location, 0,
5382                                      G_("passing argument %d of %qE discards "
5383                                         "%qv qualifier from pointer target type"),
5384                                      G_("assignment discards %qv qualifier "
5385                                         "from pointer target type"),
5386                                      G_("initialization discards %qv qualifier "
5387                                         "from pointer target type"),
5388                                      G_("return discards %qv qualifier from "
5389                                         "pointer target type"),
5390                                      TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
5391
5392               memb = marginal_memb;
5393             }
5394
5395           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
5396             pedwarn (location, OPT_pedantic,
5397                      "ISO C prohibits argument conversion to union type");
5398
5399           rhs = fold_convert_loc (location, TREE_TYPE (memb), rhs);
5400           return build_constructor_single (type, memb, rhs);
5401         }
5402     }
5403
5404   /* Conversions among pointers */
5405   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
5406            && (coder == codel))
5407     {
5408       tree ttl = TREE_TYPE (type);
5409       tree ttr = TREE_TYPE (rhstype);
5410       tree mvl = ttl;
5411       tree mvr = ttr;
5412       bool is_opaque_pointer;
5413       int target_cmp = 0;   /* Cache comp_target_types () result.  */
5414       addr_space_t asl;
5415       addr_space_t asr;
5416
5417       if (TREE_CODE (mvl) != ARRAY_TYPE)
5418         mvl = TYPE_MAIN_VARIANT (mvl);
5419       if (TREE_CODE (mvr) != ARRAY_TYPE)
5420         mvr = TYPE_MAIN_VARIANT (mvr);
5421       /* Opaque pointers are treated like void pointers.  */
5422       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
5423
5424       /* The Plan 9 compiler permits a pointer to a struct to be
5425          automatically converted into a pointer to an anonymous field
5426          within the struct.  */
5427       if (flag_plan9_extensions
5428           && (TREE_CODE (mvl) == RECORD_TYPE || TREE_CODE(mvl) == UNION_TYPE)
5429           && (TREE_CODE (mvr) == RECORD_TYPE || TREE_CODE(mvr) == UNION_TYPE)
5430           && mvl != mvr)
5431         {
5432           tree new_rhs = convert_to_anonymous_field (location, type, rhs);
5433           if (new_rhs != NULL_TREE)
5434             {
5435               rhs = new_rhs;
5436               rhstype = TREE_TYPE (rhs);
5437               coder = TREE_CODE (rhstype);
5438               ttr = TREE_TYPE (rhstype);
5439               mvr = TYPE_MAIN_VARIANT (ttr);
5440             }
5441         }
5442
5443       /* C++ does not allow the implicit conversion void* -> T*.  However,
5444          for the purpose of reducing the number of false positives, we
5445          tolerate the special case of
5446
5447                 int *p = NULL;
5448
5449          where NULL is typically defined in C to be '(void *) 0'.  */
5450       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
5451         warning_at (location, OPT_Wc___compat,
5452                     "request for implicit conversion "
5453                     "from %qT to %qT not permitted in C++", rhstype, type);
5454
5455       /* See if the pointers point to incompatible address spaces.  */
5456       asl = TYPE_ADDR_SPACE (ttl);
5457       asr = TYPE_ADDR_SPACE (ttr);
5458       if (!null_pointer_constant_p (rhs)
5459           && asr != asl && !targetm.addr_space.subset_p (asr, asl))
5460         {
5461           switch (errtype)
5462             {
5463             case ic_argpass:
5464               error_at (location, "passing argument %d of %qE from pointer to "
5465                         "non-enclosed address space", parmnum, rname);
5466               break;
5467             case ic_assign:
5468               error_at (location, "assignment from pointer to "
5469                         "non-enclosed address space");
5470               break;
5471             case ic_init:
5472               error_at (location, "initialization from pointer to "
5473                         "non-enclosed address space");
5474               break;
5475             case ic_return:
5476               error_at (location, "return from pointer to "
5477                         "non-enclosed address space");
5478               break;
5479             default:
5480               gcc_unreachable ();
5481             }
5482           return error_mark_node;
5483         }
5484
5485       /* Check if the right-hand side has a format attribute but the
5486          left-hand side doesn't.  */
5487       if (warn_missing_format_attribute
5488           && check_missing_format_attribute (type, rhstype))
5489         {
5490           switch (errtype)
5491           {
5492           case ic_argpass:
5493             warning_at (location, OPT_Wmissing_format_attribute,
5494                         "argument %d of %qE might be "
5495                         "a candidate for a format attribute",
5496                         parmnum, rname);
5497             break;
5498           case ic_assign:
5499             warning_at (location, OPT_Wmissing_format_attribute,
5500                         "assignment left-hand side might be "
5501                         "a candidate for a format attribute");
5502             break;
5503           case ic_init:
5504             warning_at (location, OPT_Wmissing_format_attribute,
5505                         "initialization left-hand side might be "
5506                         "a candidate for a format attribute");
5507             break;
5508           case ic_return:
5509             warning_at (location, OPT_Wmissing_format_attribute,
5510                         "return type might be "
5511                         "a candidate for a format attribute");
5512             break;
5513           default:
5514             gcc_unreachable ();
5515           }
5516         }
5517
5518       /* Any non-function converts to a [const][volatile] void *
5519          and vice versa; otherwise, targets must be the same.
5520          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5521       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5522           || (target_cmp = comp_target_types (location, type, rhstype))
5523           || is_opaque_pointer
5524           || (c_common_unsigned_type (mvl)
5525               == c_common_unsigned_type (mvr)))
5526         {
5527           if (pedantic
5528               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5529                   ||
5530                   (VOID_TYPE_P (ttr)
5531                    && !null_pointer_constant
5532                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5533             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5534                                  G_("ISO C forbids passing argument %d of "
5535                                     "%qE between function pointer "
5536                                     "and %<void *%>"),
5537                                  G_("ISO C forbids assignment between "
5538                                     "function pointer and %<void *%>"),
5539                                  G_("ISO C forbids initialization between "
5540                                     "function pointer and %<void *%>"),
5541                                  G_("ISO C forbids return between function "
5542                                     "pointer and %<void *%>"));
5543           /* Const and volatile mean something different for function types,
5544              so the usual warnings are not appropriate.  */
5545           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5546                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5547             {
5548               if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5549                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5550                 {
5551                   WARN_FOR_QUALIFIERS (location, 0,
5552                                        G_("passing argument %d of %qE discards "
5553                                           "%qv qualifier from pointer target type"),
5554                                        G_("assignment discards %qv qualifier "
5555                                           "from pointer target type"),
5556                                        G_("initialization discards %qv qualifier "
5557                                           "from pointer target type"),
5558                                        G_("return discards %qv qualifier from "
5559                                           "pointer target type"),
5560                                        TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
5561                 }
5562               /* If this is not a case of ignoring a mismatch in signedness,
5563                  no warning.  */
5564               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5565                        || target_cmp)
5566                 ;
5567               /* If there is a mismatch, do warn.  */
5568               else if (warn_pointer_sign)
5569                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5570                                      G_("pointer targets in passing argument "
5571                                         "%d of %qE differ in signedness"),
5572                                      G_("pointer targets in assignment "
5573                                         "differ in signedness"),
5574                                      G_("pointer targets in initialization "
5575                                         "differ in signedness"),
5576                                      G_("pointer targets in return differ "
5577                                         "in signedness"));
5578             }
5579           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5580                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5581             {
5582               /* Because const and volatile on functions are restrictions
5583                  that say the function will not do certain things,
5584                  it is okay to use a const or volatile function
5585                  where an ordinary one is wanted, but not vice-versa.  */
5586               if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5587                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5588                 WARN_FOR_QUALIFIERS (location, 0,
5589                                      G_("passing argument %d of %qE makes "
5590                                         "%q#v qualified function pointer "
5591                                         "from unqualified"),
5592                                      G_("assignment makes %q#v qualified function "
5593                                         "pointer from unqualified"),
5594                                      G_("initialization makes %q#v qualified "
5595                                         "function pointer from unqualified"),
5596                                      G_("return makes %q#v qualified function "
5597                                         "pointer from unqualified"),
5598                                      TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr));
5599             }
5600         }
5601       else
5602         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5603         if (!objc_ok)
5604           WARN_FOR_ASSIGNMENT (location, 0,
5605                                G_("passing argument %d of %qE from "
5606                                   "incompatible pointer type"),
5607                                G_("assignment from incompatible pointer type"),
5608                                G_("initialization from incompatible "
5609                                   "pointer type"),
5610                                G_("return from incompatible pointer type"));
5611
5612       return convert (type, rhs);
5613     }
5614   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5615     {
5616       /* ??? This should not be an error when inlining calls to
5617          unprototyped functions.  */
5618       error_at (location, "invalid use of non-lvalue array");
5619       return error_mark_node;
5620     }
5621   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5622     {
5623       /* An explicit constant 0 can convert to a pointer,
5624          or one that results from arithmetic, even including
5625          a cast to integer type.  */
5626       if (!null_pointer_constant)
5627         WARN_FOR_ASSIGNMENT (location, 0,
5628                              G_("passing argument %d of %qE makes "
5629                                 "pointer from integer without a cast"),
5630                              G_("assignment makes pointer from integer "
5631                                 "without a cast"),
5632                              G_("initialization makes pointer from "
5633                                 "integer without a cast"),
5634                              G_("return makes pointer from integer "
5635                                 "without a cast"));
5636
5637       return convert (type, rhs);
5638     }
5639   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5640     {
5641       WARN_FOR_ASSIGNMENT (location, 0,
5642                            G_("passing argument %d of %qE makes integer "
5643                               "from pointer without a cast"),
5644                            G_("assignment makes integer from pointer "
5645                               "without a cast"),
5646                            G_("initialization makes integer from pointer "
5647                               "without a cast"),
5648                            G_("return makes integer from pointer "
5649                               "without a cast"));
5650       return convert (type, rhs);
5651     }
5652   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5653     {
5654       tree ret;
5655       bool save = in_late_binary_op;
5656       in_late_binary_op = true;
5657       ret = convert (type, rhs);
5658       in_late_binary_op = save;
5659       return ret;
5660     }
5661
5662   switch (errtype)
5663     {
5664     case ic_argpass:
5665       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5666       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5667               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5668               "expected %qT but argument is of type %qT", type, rhstype);
5669       break;
5670     case ic_assign:
5671       error_at (location, "incompatible types when assigning to type %qT from "
5672                 "type %qT", type, rhstype);
5673       break;
5674     case ic_init:
5675       error_at (location,
5676                 "incompatible types when initializing type %qT using type %qT",
5677                 type, rhstype);
5678       break;
5679     case ic_return:
5680       error_at (location,
5681                 "incompatible types when returning type %qT but %qT was "
5682                 "expected", rhstype, type);
5683       break;
5684     default:
5685       gcc_unreachable ();
5686     }
5687
5688   return error_mark_node;
5689 }
5690 \f
5691 /* If VALUE is a compound expr all of whose expressions are constant, then
5692    return its value.  Otherwise, return error_mark_node.
5693
5694    This is for handling COMPOUND_EXPRs as initializer elements
5695    which is allowed with a warning when -pedantic is specified.  */
5696
5697 static tree
5698 valid_compound_expr_initializer (tree value, tree endtype)
5699 {
5700   if (TREE_CODE (value) == COMPOUND_EXPR)
5701     {
5702       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5703           == error_mark_node)
5704         return error_mark_node;
5705       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5706                                               endtype);
5707     }
5708   else if (!initializer_constant_valid_p (value, endtype))
5709     return error_mark_node;
5710   else
5711     return value;
5712 }
5713 \f
5714 /* Perform appropriate conversions on the initial value of a variable,
5715    store it in the declaration DECL,
5716    and print any error messages that are appropriate.
5717    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5718    If the init is invalid, store an ERROR_MARK.
5719
5720    INIT_LOC is the location of the initial value.  */
5721
5722 void
5723 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5724 {
5725   tree value, type;
5726   bool npc = false;
5727
5728   /* If variable's type was invalidly declared, just ignore it.  */
5729
5730   type = TREE_TYPE (decl);
5731   if (TREE_CODE (type) == ERROR_MARK)
5732     return;
5733
5734   /* Digest the specified initializer into an expression.  */
5735
5736   if (init)
5737     npc = null_pointer_constant_p (init);
5738   value = digest_init (init_loc, type, init, origtype, npc,
5739                        true, TREE_STATIC (decl));
5740
5741   /* Store the expression if valid; else report error.  */
5742
5743   if (!in_system_header
5744       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5745     warning (OPT_Wtraditional, "traditional C rejects automatic "
5746              "aggregate initialization");
5747
5748   DECL_INITIAL (decl) = value;
5749
5750   /* ANSI wants warnings about out-of-range constant initializers.  */
5751   STRIP_TYPE_NOPS (value);
5752   if (TREE_STATIC (decl))
5753     constant_expression_warning (value);
5754
5755   /* Check if we need to set array size from compound literal size.  */
5756   if (TREE_CODE (type) == ARRAY_TYPE
5757       && TYPE_DOMAIN (type) == 0
5758       && value != error_mark_node)
5759     {
5760       tree inside_init = init;
5761
5762       STRIP_TYPE_NOPS (inside_init);
5763       inside_init = fold (inside_init);
5764
5765       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5766         {
5767           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5768
5769           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5770             {
5771               /* For int foo[] = (int [3]){1}; we need to set array size
5772                  now since later on array initializer will be just the
5773                  brace enclosed list of the compound literal.  */
5774               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5775               TREE_TYPE (decl) = type;
5776               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5777               layout_type (type);
5778               layout_decl (cldecl, 0);
5779             }
5780         }
5781     }
5782 }
5783 \f
5784 /* Methods for storing and printing names for error messages.  */
5785
5786 /* Implement a spelling stack that allows components of a name to be pushed
5787    and popped.  Each element on the stack is this structure.  */
5788
5789 struct spelling
5790 {
5791   int kind;
5792   union
5793     {
5794       unsigned HOST_WIDE_INT i;
5795       const char *s;
5796     } u;
5797 };
5798
5799 #define SPELLING_STRING 1
5800 #define SPELLING_MEMBER 2
5801 #define SPELLING_BOUNDS 3
5802
5803 static struct spelling *spelling;       /* Next stack element (unused).  */
5804 static struct spelling *spelling_base;  /* Spelling stack base.  */
5805 static int spelling_size;               /* Size of the spelling stack.  */
5806
5807 /* Macros to save and restore the spelling stack around push_... functions.
5808    Alternative to SAVE_SPELLING_STACK.  */
5809
5810 #define SPELLING_DEPTH() (spelling - spelling_base)
5811 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5812
5813 /* Push an element on the spelling stack with type KIND and assign VALUE
5814    to MEMBER.  */
5815
5816 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5817 {                                                                       \
5818   int depth = SPELLING_DEPTH ();                                        \
5819                                                                         \
5820   if (depth >= spelling_size)                                           \
5821     {                                                                   \
5822       spelling_size += 10;                                              \
5823       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5824                                   spelling_size);                       \
5825       RESTORE_SPELLING_DEPTH (depth);                                   \
5826     }                                                                   \
5827                                                                         \
5828   spelling->kind = (KIND);                                              \
5829   spelling->MEMBER = (VALUE);                                           \
5830   spelling++;                                                           \
5831 }
5832
5833 /* Push STRING on the stack.  Printed literally.  */
5834
5835 static void
5836 push_string (const char *string)
5837 {
5838   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5839 }
5840
5841 /* Push a member name on the stack.  Printed as '.' STRING.  */
5842
5843 static void
5844 push_member_name (tree decl)
5845 {
5846   const char *const string
5847     = (DECL_NAME (decl)
5848        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5849        : _("<anonymous>"));
5850   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5851 }
5852
5853 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5854
5855 static void
5856 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5857 {
5858   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5859 }
5860
5861 /* Compute the maximum size in bytes of the printed spelling.  */
5862
5863 static int
5864 spelling_length (void)
5865 {
5866   int size = 0;
5867   struct spelling *p;
5868
5869   for (p = spelling_base; p < spelling; p++)
5870     {
5871       if (p->kind == SPELLING_BOUNDS)
5872         size += 25;
5873       else
5874         size += strlen (p->u.s) + 1;
5875     }
5876
5877   return size;
5878 }
5879
5880 /* Print the spelling to BUFFER and return it.  */
5881
5882 static char *
5883 print_spelling (char *buffer)
5884 {
5885   char *d = buffer;
5886   struct spelling *p;
5887
5888   for (p = spelling_base; p < spelling; p++)
5889     if (p->kind == SPELLING_BOUNDS)
5890       {
5891         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5892         d += strlen (d);
5893       }
5894     else
5895       {
5896         const char *s;
5897         if (p->kind == SPELLING_MEMBER)
5898           *d++ = '.';
5899         for (s = p->u.s; (*d = *s++); d++)
5900           ;
5901       }
5902   *d++ = '\0';
5903   return buffer;
5904 }
5905
5906 /* Issue an error message for a bad initializer component.
5907    GMSGID identifies the message.
5908    The component name is taken from the spelling stack.  */
5909
5910 void
5911 error_init (const char *gmsgid)
5912 {
5913   char *ofwhat;
5914
5915   /* The gmsgid may be a format string with %< and %>. */
5916   error (gmsgid);
5917   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5918   if (*ofwhat)
5919     error ("(near initialization for %qs)", ofwhat);
5920 }
5921
5922 /* Issue a pedantic warning for a bad initializer component.  OPT is
5923    the option OPT_* (from options.h) controlling this warning or 0 if
5924    it is unconditionally given.  GMSGID identifies the message.  The
5925    component name is taken from the spelling stack.  */
5926
5927 void
5928 pedwarn_init (location_t location, int opt, const char *gmsgid)
5929 {
5930   char *ofwhat;
5931
5932   /* The gmsgid may be a format string with %< and %>. */
5933   pedwarn (location, opt, gmsgid);
5934   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5935   if (*ofwhat)
5936     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5937 }
5938
5939 /* Issue a warning for a bad initializer component.
5940
5941    OPT is the OPT_W* value corresponding to the warning option that
5942    controls this warning.  GMSGID identifies the message.  The
5943    component name is taken from the spelling stack.  */
5944
5945 static void
5946 warning_init (int opt, const char *gmsgid)
5947 {
5948   char *ofwhat;
5949
5950   /* The gmsgid may be a format string with %< and %>. */
5951   warning (opt, gmsgid);
5952   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5953   if (*ofwhat)
5954     warning (opt, "(near initialization for %qs)", ofwhat);
5955 }
5956 \f
5957 /* If TYPE is an array type and EXPR is a parenthesized string
5958    constant, warn if pedantic that EXPR is being used to initialize an
5959    object of type TYPE.  */
5960
5961 void
5962 maybe_warn_string_init (tree type, struct c_expr expr)
5963 {
5964   if (pedantic
5965       && TREE_CODE (type) == ARRAY_TYPE
5966       && TREE_CODE (expr.value) == STRING_CST
5967       && expr.original_code != STRING_CST)
5968     pedwarn_init (input_location, OPT_pedantic,
5969                   "array initialized from parenthesized string constant");
5970 }
5971
5972 /* Digest the parser output INIT as an initializer for type TYPE.
5973    Return a C expression of type TYPE to represent the initial value.
5974
5975    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5976
5977    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5978
5979    If INIT is a string constant, STRICT_STRING is true if it is
5980    unparenthesized or we should not warn here for it being parenthesized.
5981    For other types of INIT, STRICT_STRING is not used.
5982
5983    INIT_LOC is the location of the INIT.
5984
5985    REQUIRE_CONSTANT requests an error if non-constant initializers or
5986    elements are seen.  */
5987
5988 static tree
5989 digest_init (location_t init_loc, tree type, tree init, tree origtype,
5990              bool null_pointer_constant, bool strict_string,
5991              int require_constant)
5992 {
5993   enum tree_code code = TREE_CODE (type);
5994   tree inside_init = init;
5995   tree semantic_type = NULL_TREE;
5996   bool maybe_const = true;
5997
5998   if (type == error_mark_node
5999       || !init
6000       || init == error_mark_node
6001       || TREE_TYPE (init) == error_mark_node)
6002     return error_mark_node;
6003
6004   STRIP_TYPE_NOPS (inside_init);
6005
6006   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
6007     {
6008       semantic_type = TREE_TYPE (inside_init);
6009       inside_init = TREE_OPERAND (inside_init, 0);
6010     }
6011   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
6012   inside_init = decl_constant_value_for_optimization (inside_init);
6013
6014   /* Initialization of an array of chars from a string constant
6015      optionally enclosed in braces.  */
6016
6017   if (code == ARRAY_TYPE && inside_init
6018       && TREE_CODE (inside_init) == STRING_CST)
6019     {
6020       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
6021       /* Note that an array could be both an array of character type
6022          and an array of wchar_t if wchar_t is signed char or unsigned
6023          char.  */
6024       bool char_array = (typ1 == char_type_node
6025                          || typ1 == signed_char_type_node
6026                          || typ1 == unsigned_char_type_node);
6027       bool wchar_array = !!comptypes (typ1, wchar_type_node);
6028       bool char16_array = !!comptypes (typ1, char16_type_node);
6029       bool char32_array = !!comptypes (typ1, char32_type_node);
6030
6031       if (char_array || wchar_array || char16_array || char32_array)
6032         {
6033           struct c_expr expr;
6034           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
6035           expr.value = inside_init;
6036           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
6037           expr.original_type = NULL;
6038           maybe_warn_string_init (type, expr);
6039
6040           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
6041             pedwarn_init (init_loc, OPT_pedantic,
6042                           "initialization of a flexible array member");
6043
6044           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6045                          TYPE_MAIN_VARIANT (type)))
6046             return inside_init;
6047
6048           if (char_array)
6049             {
6050               if (typ2 != char_type_node)
6051                 {
6052                   error_init ("char-array initialized from wide string");
6053                   return error_mark_node;
6054                 }
6055             }
6056           else
6057             {
6058               if (typ2 == char_type_node)
6059                 {
6060                   error_init ("wide character array initialized from non-wide "
6061                               "string");
6062                   return error_mark_node;
6063                 }
6064               else if (!comptypes(typ1, typ2))
6065                 {
6066                   error_init ("wide character array initialized from "
6067                               "incompatible wide string");
6068                   return error_mark_node;
6069                 }
6070             }
6071
6072           TREE_TYPE (inside_init) = type;
6073           if (TYPE_DOMAIN (type) != 0
6074               && TYPE_SIZE (type) != 0
6075               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
6076             {
6077               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
6078
6079               /* Subtract the size of a single (possibly wide) character
6080                  because it's ok to ignore the terminating null char
6081                  that is counted in the length of the constant.  */
6082               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
6083                                         (len
6084                                          - (TYPE_PRECISION (typ1)
6085                                             / BITS_PER_UNIT))))
6086                 pedwarn_init (init_loc, 0,
6087                               ("initializer-string for array of chars "
6088                                "is too long"));
6089               else if (warn_cxx_compat
6090                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
6091                 warning_at (init_loc, OPT_Wc___compat,
6092                             ("initializer-string for array chars "
6093                              "is too long for C++"));
6094             }
6095
6096           return inside_init;
6097         }
6098       else if (INTEGRAL_TYPE_P (typ1))
6099         {
6100           error_init ("array of inappropriate type initialized "
6101                       "from string constant");
6102           return error_mark_node;
6103         }
6104     }
6105
6106   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
6107      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
6108      below and handle as a constructor.  */
6109   if (code == VECTOR_TYPE
6110       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
6111       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
6112       && TREE_CONSTANT (inside_init))
6113     {
6114       if (TREE_CODE (inside_init) == VECTOR_CST
6115           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6116                         TYPE_MAIN_VARIANT (type)))
6117         return inside_init;
6118
6119       if (TREE_CODE (inside_init) == CONSTRUCTOR)
6120         {
6121           unsigned HOST_WIDE_INT ix;
6122           tree value;
6123           bool constant_p = true;
6124
6125           /* Iterate through elements and check if all constructor
6126              elements are *_CSTs.  */
6127           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
6128             if (!CONSTANT_CLASS_P (value))
6129               {
6130                 constant_p = false;
6131                 break;
6132               }
6133
6134           if (constant_p)
6135             return build_vector_from_ctor (type,
6136                                            CONSTRUCTOR_ELTS (inside_init));
6137         }
6138     }
6139
6140   if (warn_sequence_point)
6141     verify_sequence_points (inside_init);
6142
6143   /* Any type can be initialized
6144      from an expression of the same type, optionally with braces.  */
6145
6146   if (inside_init && TREE_TYPE (inside_init) != 0
6147       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
6148                      TYPE_MAIN_VARIANT (type))
6149           || (code == ARRAY_TYPE
6150               && comptypes (TREE_TYPE (inside_init), type))
6151           || (code == VECTOR_TYPE
6152               && comptypes (TREE_TYPE (inside_init), type))
6153           || (code == POINTER_TYPE
6154               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
6155               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
6156                             TREE_TYPE (type)))))
6157     {
6158       if (code == POINTER_TYPE)
6159         {
6160           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
6161             {
6162               if (TREE_CODE (inside_init) == STRING_CST
6163                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
6164                 inside_init = array_to_pointer_conversion
6165                   (init_loc, inside_init);
6166               else
6167                 {
6168                   error_init ("invalid use of non-lvalue array");
6169                   return error_mark_node;
6170                 }
6171             }
6172         }
6173
6174       if (code == VECTOR_TYPE)
6175         /* Although the types are compatible, we may require a
6176            conversion.  */
6177         inside_init = convert (type, inside_init);
6178
6179       if (require_constant
6180           && (code == VECTOR_TYPE || !flag_isoc99)
6181           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
6182         {
6183           /* As an extension, allow initializing objects with static storage
6184              duration with compound literals (which are then treated just as
6185              the brace enclosed list they contain).  Also allow this for
6186              vectors, as we can only assign them with compound literals.  */
6187           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
6188           inside_init = DECL_INITIAL (decl);
6189         }
6190
6191       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
6192           && TREE_CODE (inside_init) != CONSTRUCTOR)
6193         {
6194           error_init ("array initialized from non-constant array expression");
6195           return error_mark_node;
6196         }
6197
6198       /* Compound expressions can only occur here if -pedantic or
6199          -pedantic-errors is specified.  In the later case, we always want
6200          an error.  In the former case, we simply want a warning.  */
6201       if (require_constant && pedantic
6202           && TREE_CODE (inside_init) == COMPOUND_EXPR)
6203         {
6204           inside_init
6205             = valid_compound_expr_initializer (inside_init,
6206                                                TREE_TYPE (inside_init));
6207           if (inside_init == error_mark_node)
6208             error_init ("initializer element is not constant");
6209           else
6210             pedwarn_init (init_loc, OPT_pedantic,
6211                           "initializer element is not constant");
6212           if (flag_pedantic_errors)
6213             inside_init = error_mark_node;
6214         }
6215       else if (require_constant
6216                && !initializer_constant_valid_p (inside_init,
6217                                                  TREE_TYPE (inside_init)))
6218         {
6219           error_init ("initializer element is not constant");
6220           inside_init = error_mark_node;
6221         }
6222       else if (require_constant && !maybe_const)
6223         pedwarn_init (init_loc, 0,
6224                       "initializer element is not a constant expression");
6225
6226       /* Added to enable additional -Wmissing-format-attribute warnings.  */
6227       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
6228         inside_init = convert_for_assignment (init_loc, type, inside_init,
6229                                               origtype,
6230                                               ic_init, null_pointer_constant,
6231                                               NULL_TREE, NULL_TREE, 0);
6232       return inside_init;
6233     }
6234
6235   /* Handle scalar types, including conversions.  */
6236
6237   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
6238       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
6239       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
6240     {
6241       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
6242           && (TREE_CODE (init) == STRING_CST
6243               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
6244         inside_init = init = array_to_pointer_conversion (init_loc, init);
6245       if (semantic_type)
6246         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
6247                               inside_init);
6248       inside_init
6249         = convert_for_assignment (init_loc, type, inside_init, origtype,
6250                                   ic_init, null_pointer_constant,
6251                                   NULL_TREE, NULL_TREE, 0);
6252
6253       /* Check to see if we have already given an error message.  */
6254       if (inside_init == error_mark_node)
6255         ;
6256       else if (require_constant && !TREE_CONSTANT (inside_init))
6257         {
6258           error_init ("initializer element is not constant");
6259           inside_init = error_mark_node;
6260         }
6261       else if (require_constant
6262                && !initializer_constant_valid_p (inside_init,
6263                                                  TREE_TYPE (inside_init)))
6264         {
6265           error_init ("initializer element is not computable at load time");
6266           inside_init = error_mark_node;
6267         }
6268       else if (require_constant && !maybe_const)
6269         pedwarn_init (init_loc, 0,
6270                       "initializer element is not a constant expression");
6271
6272       return inside_init;
6273     }
6274
6275   /* Come here only for records and arrays.  */
6276
6277   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
6278     {
6279       error_init ("variable-sized object may not be initialized");
6280       return error_mark_node;
6281     }
6282
6283   error_init ("invalid initializer");
6284   return error_mark_node;
6285 }
6286 \f
6287 /* Handle initializers that use braces.  */
6288
6289 /* Type of object we are accumulating a constructor for.
6290    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
6291 static tree constructor_type;
6292
6293 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
6294    left to fill.  */
6295 static tree constructor_fields;
6296
6297 /* For an ARRAY_TYPE, this is the specified index
6298    at which to store the next element we get.  */
6299 static tree constructor_index;
6300
6301 /* For an ARRAY_TYPE, this is the maximum index.  */
6302 static tree constructor_max_index;
6303
6304 /* For a RECORD_TYPE, this is the first field not yet written out.  */
6305 static tree constructor_unfilled_fields;
6306
6307 /* For an ARRAY_TYPE, this is the index of the first element
6308    not yet written out.  */
6309 static tree constructor_unfilled_index;
6310
6311 /* In a RECORD_TYPE, the byte index of the next consecutive field.
6312    This is so we can generate gaps between fields, when appropriate.  */
6313 static tree constructor_bit_index;
6314
6315 /* If we are saving up the elements rather than allocating them,
6316    this is the list of elements so far (in reverse order,
6317    most recent first).  */
6318 static VEC(constructor_elt,gc) *constructor_elements;
6319
6320 /* 1 if constructor should be incrementally stored into a constructor chain,
6321    0 if all the elements should be kept in AVL tree.  */
6322 static int constructor_incremental;
6323
6324 /* 1 if so far this constructor's elements are all compile-time constants.  */
6325 static int constructor_constant;
6326
6327 /* 1 if so far this constructor's elements are all valid address constants.  */
6328 static int constructor_simple;
6329
6330 /* 1 if this constructor has an element that cannot be part of a
6331    constant expression.  */
6332 static int constructor_nonconst;
6333
6334 /* 1 if this constructor is erroneous so far.  */
6335 static int constructor_erroneous;
6336
6337 /* Structure for managing pending initializer elements, organized as an
6338    AVL tree.  */
6339
6340 struct init_node
6341 {
6342   struct init_node *left, *right;
6343   struct init_node *parent;
6344   int balance;
6345   tree purpose;
6346   tree value;
6347   tree origtype;
6348 };
6349
6350 /* Tree of pending elements at this constructor level.
6351    These are elements encountered out of order
6352    which belong at places we haven't reached yet in actually
6353    writing the output.
6354    Will never hold tree nodes across GC runs.  */
6355 static struct init_node *constructor_pending_elts;
6356
6357 /* The SPELLING_DEPTH of this constructor.  */
6358 static int constructor_depth;
6359
6360 /* DECL node for which an initializer is being read.
6361    0 means we are reading a constructor expression
6362    such as (struct foo) {...}.  */
6363 static tree constructor_decl;
6364
6365 /* Nonzero if this is an initializer for a top-level decl.  */
6366 static int constructor_top_level;
6367
6368 /* Nonzero if there were any member designators in this initializer.  */
6369 static int constructor_designated;
6370
6371 /* Nesting depth of designator list.  */
6372 static int designator_depth;
6373
6374 /* Nonzero if there were diagnosed errors in this designator list.  */
6375 static int designator_erroneous;
6376
6377 \f
6378 /* This stack has a level for each implicit or explicit level of
6379    structuring in the initializer, including the outermost one.  It
6380    saves the values of most of the variables above.  */
6381
6382 struct constructor_range_stack;
6383
6384 struct constructor_stack
6385 {
6386   struct constructor_stack *next;
6387   tree type;
6388   tree fields;
6389   tree index;
6390   tree max_index;
6391   tree unfilled_index;
6392   tree unfilled_fields;
6393   tree bit_index;
6394   VEC(constructor_elt,gc) *elements;
6395   struct init_node *pending_elts;
6396   int offset;
6397   int depth;
6398   /* If value nonzero, this value should replace the entire
6399      constructor at this level.  */
6400   struct c_expr replacement_value;
6401   struct constructor_range_stack *range_stack;
6402   char constant;
6403   char simple;
6404   char nonconst;
6405   char implicit;
6406   char erroneous;
6407   char outer;
6408   char incremental;
6409   char designated;
6410 };
6411
6412 static struct constructor_stack *constructor_stack;
6413
6414 /* This stack represents designators from some range designator up to
6415    the last designator in the list.  */
6416
6417 struct constructor_range_stack
6418 {
6419   struct constructor_range_stack *next, *prev;
6420   struct constructor_stack *stack;
6421   tree range_start;
6422   tree index;
6423   tree range_end;
6424   tree fields;
6425 };
6426
6427 static struct constructor_range_stack *constructor_range_stack;
6428
6429 /* This stack records separate initializers that are nested.
6430    Nested initializers can't happen in ANSI C, but GNU C allows them
6431    in cases like { ... (struct foo) { ... } ... }.  */
6432
6433 struct initializer_stack
6434 {
6435   struct initializer_stack *next;
6436   tree decl;
6437   struct constructor_stack *constructor_stack;
6438   struct constructor_range_stack *constructor_range_stack;
6439   VEC(constructor_elt,gc) *elements;
6440   struct spelling *spelling;
6441   struct spelling *spelling_base;
6442   int spelling_size;
6443   char top_level;
6444   char require_constant_value;
6445   char require_constant_elements;
6446 };
6447
6448 static struct initializer_stack *initializer_stack;
6449 \f
6450 /* Prepare to parse and output the initializer for variable DECL.  */
6451
6452 void
6453 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
6454 {
6455   const char *locus;
6456   struct initializer_stack *p = XNEW (struct initializer_stack);
6457
6458   p->decl = constructor_decl;
6459   p->require_constant_value = require_constant_value;
6460   p->require_constant_elements = require_constant_elements;
6461   p->constructor_stack = constructor_stack;
6462   p->constructor_range_stack = constructor_range_stack;
6463   p->elements = constructor_elements;
6464   p->spelling = spelling;
6465   p->spelling_base = spelling_base;
6466   p->spelling_size = spelling_size;
6467   p->top_level = constructor_top_level;
6468   p->next = initializer_stack;
6469   initializer_stack = p;
6470
6471   constructor_decl = decl;
6472   constructor_designated = 0;
6473   constructor_top_level = top_level;
6474
6475   if (decl != 0 && decl != error_mark_node)
6476     {
6477       require_constant_value = TREE_STATIC (decl);
6478       require_constant_elements
6479         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
6480            /* For a scalar, you can always use any value to initialize,
6481               even within braces.  */
6482            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
6483                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
6484                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
6485                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
6486       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
6487     }
6488   else
6489     {
6490       require_constant_value = 0;
6491       require_constant_elements = 0;
6492       locus = _("(anonymous)");
6493     }
6494
6495   constructor_stack = 0;
6496   constructor_range_stack = 0;
6497
6498   missing_braces_mentioned = 0;
6499
6500   spelling_base = 0;
6501   spelling_size = 0;
6502   RESTORE_SPELLING_DEPTH (0);
6503
6504   if (locus)
6505     push_string (locus);
6506 }
6507
6508 void
6509 finish_init (void)
6510 {
6511   struct initializer_stack *p = initializer_stack;
6512
6513   /* Free the whole constructor stack of this initializer.  */
6514   while (constructor_stack)
6515     {
6516       struct constructor_stack *q = constructor_stack;
6517       constructor_stack = q->next;
6518       free (q);
6519     }
6520
6521   gcc_assert (!constructor_range_stack);
6522
6523   /* Pop back to the data of the outer initializer (if any).  */
6524   free (spelling_base);
6525
6526   constructor_decl = p->decl;
6527   require_constant_value = p->require_constant_value;
6528   require_constant_elements = p->require_constant_elements;
6529   constructor_stack = p->constructor_stack;
6530   constructor_range_stack = p->constructor_range_stack;
6531   constructor_elements = p->elements;
6532   spelling = p->spelling;
6533   spelling_base = p->spelling_base;
6534   spelling_size = p->spelling_size;
6535   constructor_top_level = p->top_level;
6536   initializer_stack = p->next;
6537   free (p);
6538 }
6539 \f
6540 /* Call here when we see the initializer is surrounded by braces.
6541    This is instead of a call to push_init_level;
6542    it is matched by a call to pop_init_level.
6543
6544    TYPE is the type to initialize, for a constructor expression.
6545    For an initializer for a decl, TYPE is zero.  */
6546
6547 void
6548 really_start_incremental_init (tree type)
6549 {
6550   struct constructor_stack *p = XNEW (struct constructor_stack);
6551
6552   if (type == 0)
6553     type = TREE_TYPE (constructor_decl);
6554
6555   if (TREE_CODE (type) == VECTOR_TYPE
6556       && TYPE_VECTOR_OPAQUE (type))
6557     error ("opaque vector types cannot be initialized");
6558
6559   p->type = constructor_type;
6560   p->fields = constructor_fields;
6561   p->index = constructor_index;
6562   p->max_index = constructor_max_index;
6563   p->unfilled_index = constructor_unfilled_index;
6564   p->unfilled_fields = constructor_unfilled_fields;
6565   p->bit_index = constructor_bit_index;
6566   p->elements = constructor_elements;
6567   p->constant = constructor_constant;
6568   p->simple = constructor_simple;
6569   p->nonconst = constructor_nonconst;
6570   p->erroneous = constructor_erroneous;
6571   p->pending_elts = constructor_pending_elts;
6572   p->depth = constructor_depth;
6573   p->replacement_value.value = 0;
6574   p->replacement_value.original_code = ERROR_MARK;
6575   p->replacement_value.original_type = NULL;
6576   p->implicit = 0;
6577   p->range_stack = 0;
6578   p->outer = 0;
6579   p->incremental = constructor_incremental;
6580   p->designated = constructor_designated;
6581   p->next = 0;
6582   constructor_stack = p;
6583
6584   constructor_constant = 1;
6585   constructor_simple = 1;
6586   constructor_nonconst = 0;
6587   constructor_depth = SPELLING_DEPTH ();
6588   constructor_elements = 0;
6589   constructor_pending_elts = 0;
6590   constructor_type = type;
6591   constructor_incremental = 1;
6592   constructor_designated = 0;
6593   designator_depth = 0;
6594   designator_erroneous = 0;
6595
6596   if (TREE_CODE (constructor_type) == RECORD_TYPE
6597       || TREE_CODE (constructor_type) == UNION_TYPE)
6598     {
6599       constructor_fields = TYPE_FIELDS (constructor_type);
6600       /* Skip any nameless bit fields at the beginning.  */
6601       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6602              && DECL_NAME (constructor_fields) == 0)
6603         constructor_fields = DECL_CHAIN (constructor_fields);
6604
6605       constructor_unfilled_fields = constructor_fields;
6606       constructor_bit_index = bitsize_zero_node;
6607     }
6608   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6609     {
6610       if (TYPE_DOMAIN (constructor_type))
6611         {
6612           constructor_max_index
6613             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6614
6615           /* Detect non-empty initializations of zero-length arrays.  */
6616           if (constructor_max_index == NULL_TREE
6617               && TYPE_SIZE (constructor_type))
6618             constructor_max_index = integer_minus_one_node;
6619
6620           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6621              to initialize VLAs will cause a proper error; avoid tree
6622              checking errors as well by setting a safe value.  */
6623           if (constructor_max_index
6624               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6625             constructor_max_index = integer_minus_one_node;
6626
6627           constructor_index
6628             = convert (bitsizetype,
6629                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6630         }
6631       else
6632         {
6633           constructor_index = bitsize_zero_node;
6634           constructor_max_index = NULL_TREE;
6635         }
6636
6637       constructor_unfilled_index = constructor_index;
6638     }
6639   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6640     {
6641       /* Vectors are like simple fixed-size arrays.  */
6642       constructor_max_index =
6643         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6644       constructor_index = bitsize_zero_node;
6645       constructor_unfilled_index = constructor_index;
6646     }
6647   else
6648     {
6649       /* Handle the case of int x = {5}; */
6650       constructor_fields = constructor_type;
6651       constructor_unfilled_fields = constructor_type;
6652     }
6653 }
6654 \f
6655 /* Push down into a subobject, for initialization.
6656    If this is for an explicit set of braces, IMPLICIT is 0.
6657    If it is because the next element belongs at a lower level,
6658    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6659
6660 void
6661 push_init_level (int implicit, struct obstack * braced_init_obstack)
6662 {
6663   struct constructor_stack *p;
6664   tree value = NULL_TREE;
6665
6666   /* If we've exhausted any levels that didn't have braces,
6667      pop them now.  If implicit == 1, this will have been done in
6668      process_init_element; do not repeat it here because in the case
6669      of excess initializers for an empty aggregate this leads to an
6670      infinite cycle of popping a level and immediately recreating
6671      it.  */
6672   if (implicit != 1)
6673     {
6674       while (constructor_stack->implicit)
6675         {
6676           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6677                || TREE_CODE (constructor_type) == UNION_TYPE)
6678               && constructor_fields == 0)
6679             process_init_element (pop_init_level (1, braced_init_obstack),
6680                                   true, braced_init_obstack);
6681           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6682                    && constructor_max_index
6683                    && tree_int_cst_lt (constructor_max_index,
6684                                        constructor_index))
6685             process_init_element (pop_init_level (1, braced_init_obstack),
6686                                   true, braced_init_obstack);
6687           else
6688             break;
6689         }
6690     }
6691
6692   /* Unless this is an explicit brace, we need to preserve previous
6693      content if any.  */
6694   if (implicit)
6695     {
6696       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6697            || TREE_CODE (constructor_type) == UNION_TYPE)
6698           && constructor_fields)
6699         value = find_init_member (constructor_fields, braced_init_obstack);
6700       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6701         value = find_init_member (constructor_index, braced_init_obstack);
6702     }
6703
6704   p = XNEW (struct constructor_stack);
6705   p->type = constructor_type;
6706   p->fields = constructor_fields;
6707   p->index = constructor_index;
6708   p->max_index = constructor_max_index;
6709   p->unfilled_index = constructor_unfilled_index;
6710   p->unfilled_fields = constructor_unfilled_fields;
6711   p->bit_index = constructor_bit_index;
6712   p->elements = constructor_elements;
6713   p->constant = constructor_constant;
6714   p->simple = constructor_simple;
6715   p->nonconst = constructor_nonconst;
6716   p->erroneous = constructor_erroneous;
6717   p->pending_elts = constructor_pending_elts;
6718   p->depth = constructor_depth;
6719   p->replacement_value.value = 0;
6720   p->replacement_value.original_code = ERROR_MARK;
6721   p->replacement_value.original_type = NULL;
6722   p->implicit = implicit;
6723   p->outer = 0;
6724   p->incremental = constructor_incremental;
6725   p->designated = constructor_designated;
6726   p->next = constructor_stack;
6727   p->range_stack = 0;
6728   constructor_stack = p;
6729
6730   constructor_constant = 1;
6731   constructor_simple = 1;
6732   constructor_nonconst = 0;
6733   constructor_depth = SPELLING_DEPTH ();
6734   constructor_elements = 0;
6735   constructor_incremental = 1;
6736   constructor_designated = 0;
6737   constructor_pending_elts = 0;
6738   if (!implicit)
6739     {
6740       p->range_stack = constructor_range_stack;
6741       constructor_range_stack = 0;
6742       designator_depth = 0;
6743       designator_erroneous = 0;
6744     }
6745
6746   /* Don't die if an entire brace-pair level is superfluous
6747      in the containing level.  */
6748   if (constructor_type == 0)
6749     ;
6750   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6751            || TREE_CODE (constructor_type) == UNION_TYPE)
6752     {
6753       /* Don't die if there are extra init elts at the end.  */
6754       if (constructor_fields == 0)
6755         constructor_type = 0;
6756       else
6757         {
6758           constructor_type = TREE_TYPE (constructor_fields);
6759           push_member_name (constructor_fields);
6760           constructor_depth++;
6761         }
6762     }
6763   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6764     {
6765       constructor_type = TREE_TYPE (constructor_type);
6766       push_array_bounds (tree_low_cst (constructor_index, 1));
6767       constructor_depth++;
6768     }
6769
6770   if (constructor_type == 0)
6771     {
6772       error_init ("extra brace group at end of initializer");
6773       constructor_fields = 0;
6774       constructor_unfilled_fields = 0;
6775       return;
6776     }
6777
6778   if (value && TREE_CODE (value) == CONSTRUCTOR)
6779     {
6780       constructor_constant = TREE_CONSTANT (value);
6781       constructor_simple = TREE_STATIC (value);
6782       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6783       constructor_elements = CONSTRUCTOR_ELTS (value);
6784       if (!VEC_empty (constructor_elt, constructor_elements)
6785           && (TREE_CODE (constructor_type) == RECORD_TYPE
6786               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6787         set_nonincremental_init (braced_init_obstack);
6788     }
6789
6790   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6791     {
6792       missing_braces_mentioned = 1;
6793       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6794     }
6795
6796   if (TREE_CODE (constructor_type) == RECORD_TYPE
6797            || TREE_CODE (constructor_type) == UNION_TYPE)
6798     {
6799       constructor_fields = TYPE_FIELDS (constructor_type);
6800       /* Skip any nameless bit fields at the beginning.  */
6801       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6802              && DECL_NAME (constructor_fields) == 0)
6803         constructor_fields = DECL_CHAIN (constructor_fields);
6804
6805       constructor_unfilled_fields = constructor_fields;
6806       constructor_bit_index = bitsize_zero_node;
6807     }
6808   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6809     {
6810       /* Vectors are like simple fixed-size arrays.  */
6811       constructor_max_index =
6812         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6813       constructor_index = convert (bitsizetype, integer_zero_node);
6814       constructor_unfilled_index = constructor_index;
6815     }
6816   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6817     {
6818       if (TYPE_DOMAIN (constructor_type))
6819         {
6820           constructor_max_index
6821             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6822
6823           /* Detect non-empty initializations of zero-length arrays.  */
6824           if (constructor_max_index == NULL_TREE
6825               && TYPE_SIZE (constructor_type))
6826             constructor_max_index = integer_minus_one_node;
6827
6828           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6829              to initialize VLAs will cause a proper error; avoid tree
6830              checking errors as well by setting a safe value.  */
6831           if (constructor_max_index
6832               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6833             constructor_max_index = integer_minus_one_node;
6834
6835           constructor_index
6836             = convert (bitsizetype,
6837                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6838         }
6839       else
6840         constructor_index = bitsize_zero_node;
6841
6842       constructor_unfilled_index = constructor_index;
6843       if (value && TREE_CODE (value) == STRING_CST)
6844         {
6845           /* We need to split the char/wchar array into individual
6846              characters, so that we don't have to special case it
6847              everywhere.  */
6848           set_nonincremental_init_from_string (value, braced_init_obstack);
6849         }
6850     }
6851   else
6852     {
6853       if (constructor_type != error_mark_node)
6854         warning_init (0, "braces around scalar initializer");
6855       constructor_fields = constructor_type;
6856       constructor_unfilled_fields = constructor_type;
6857     }
6858 }
6859
6860 /* At the end of an implicit or explicit brace level,
6861    finish up that level of constructor.  If a single expression
6862    with redundant braces initialized that level, return the
6863    c_expr structure for that expression.  Otherwise, the original_code
6864    element is set to ERROR_MARK.
6865    If we were outputting the elements as they are read, return 0 as the value
6866    from inner levels (process_init_element ignores that),
6867    but return error_mark_node as the value from the outermost level
6868    (that's what we want to put in DECL_INITIAL).
6869    Otherwise, return a CONSTRUCTOR expression as the value.  */
6870
6871 struct c_expr
6872 pop_init_level (int implicit, struct obstack * braced_init_obstack)
6873 {
6874   struct constructor_stack *p;
6875   struct c_expr ret;
6876   ret.value = 0;
6877   ret.original_code = ERROR_MARK;
6878   ret.original_type = NULL;
6879
6880   if (implicit == 0)
6881     {
6882       /* When we come to an explicit close brace,
6883          pop any inner levels that didn't have explicit braces.  */
6884       while (constructor_stack->implicit)
6885         {
6886           process_init_element (pop_init_level (1, braced_init_obstack),
6887                                 true, braced_init_obstack);
6888         }
6889       gcc_assert (!constructor_range_stack);
6890     }
6891
6892   /* Now output all pending elements.  */
6893   constructor_incremental = 1;
6894   output_pending_init_elements (1, braced_init_obstack);
6895
6896   p = constructor_stack;
6897
6898   /* Error for initializing a flexible array member, or a zero-length
6899      array member in an inappropriate context.  */
6900   if (constructor_type && constructor_fields
6901       && TREE_CODE (constructor_type) == ARRAY_TYPE
6902       && TYPE_DOMAIN (constructor_type)
6903       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6904     {
6905       /* Silently discard empty initializations.  The parser will
6906          already have pedwarned for empty brackets.  */
6907       if (integer_zerop (constructor_unfilled_index))
6908         constructor_type = NULL_TREE;
6909       else
6910         {
6911           gcc_assert (!TYPE_SIZE (constructor_type));
6912
6913           if (constructor_depth > 2)
6914             error_init ("initialization of flexible array member in a nested context");
6915           else
6916             pedwarn_init (input_location, OPT_pedantic,
6917                           "initialization of a flexible array member");
6918
6919           /* We have already issued an error message for the existence
6920              of a flexible array member not at the end of the structure.
6921              Discard the initializer so that we do not die later.  */
6922           if (DECL_CHAIN (constructor_fields) != NULL_TREE)
6923             constructor_type = NULL_TREE;
6924         }
6925     }
6926
6927   /* Warn when some struct elements are implicitly initialized to zero.  */
6928   if (warn_missing_field_initializers
6929       && constructor_type
6930       && TREE_CODE (constructor_type) == RECORD_TYPE
6931       && constructor_unfilled_fields)
6932     {
6933         /* Do not warn for flexible array members or zero-length arrays.  */
6934         while (constructor_unfilled_fields
6935                && (!DECL_SIZE (constructor_unfilled_fields)
6936                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6937           constructor_unfilled_fields = DECL_CHAIN (constructor_unfilled_fields);
6938
6939         /* Do not warn if this level of the initializer uses member
6940            designators; it is likely to be deliberate.  */
6941         if (constructor_unfilled_fields && !constructor_designated)
6942           {
6943             push_member_name (constructor_unfilled_fields);
6944             warning_init (OPT_Wmissing_field_initializers,
6945                           "missing initializer");
6946             RESTORE_SPELLING_DEPTH (constructor_depth);
6947           }
6948     }
6949
6950   /* Pad out the end of the structure.  */
6951   if (p->replacement_value.value)
6952     /* If this closes a superfluous brace pair,
6953        just pass out the element between them.  */
6954     ret = p->replacement_value;
6955   else if (constructor_type == 0)
6956     ;
6957   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6958            && TREE_CODE (constructor_type) != UNION_TYPE
6959            && TREE_CODE (constructor_type) != ARRAY_TYPE
6960            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6961     {
6962       /* A nonincremental scalar initializer--just return
6963          the element, after verifying there is just one.  */
6964       if (VEC_empty (constructor_elt,constructor_elements))
6965         {
6966           if (!constructor_erroneous)
6967             error_init ("empty scalar initializer");
6968           ret.value = error_mark_node;
6969         }
6970       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6971         {
6972           error_init ("extra elements in scalar initializer");
6973           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6974         }
6975       else
6976         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6977     }
6978   else
6979     {
6980       if (constructor_erroneous)
6981         ret.value = error_mark_node;
6982       else
6983         {
6984           ret.value = build_constructor (constructor_type,
6985                                          constructor_elements);
6986           if (constructor_constant)
6987             TREE_CONSTANT (ret.value) = 1;
6988           if (constructor_constant && constructor_simple)
6989             TREE_STATIC (ret.value) = 1;
6990           if (constructor_nonconst)
6991             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6992         }
6993     }
6994
6995   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6996     {
6997       if (constructor_nonconst)
6998         ret.original_code = C_MAYBE_CONST_EXPR;
6999       else if (ret.original_code == C_MAYBE_CONST_EXPR)
7000         ret.original_code = ERROR_MARK;
7001     }
7002
7003   constructor_type = p->type;
7004   constructor_fields = p->fields;
7005   constructor_index = p->index;
7006   constructor_max_index = p->max_index;
7007   constructor_unfilled_index = p->unfilled_index;
7008   constructor_unfilled_fields = p->unfilled_fields;
7009   constructor_bit_index = p->bit_index;
7010   constructor_elements = p->elements;
7011   constructor_constant = p->constant;
7012   constructor_simple = p->simple;
7013   constructor_nonconst = p->nonconst;
7014   constructor_erroneous = p->erroneous;
7015   constructor_incremental = p->incremental;
7016   constructor_designated = p->designated;
7017   constructor_pending_elts = p->pending_elts;
7018   constructor_depth = p->depth;
7019   if (!p->implicit)
7020     constructor_range_stack = p->range_stack;
7021   RESTORE_SPELLING_DEPTH (constructor_depth);
7022
7023   constructor_stack = p->next;
7024   free (p);
7025
7026   if (ret.value == 0 && constructor_stack == 0)
7027     ret.value = error_mark_node;
7028   return ret;
7029 }
7030
7031 /* Common handling for both array range and field name designators.
7032    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
7033
7034 static int
7035 set_designator (int array, struct obstack * braced_init_obstack)
7036 {
7037   tree subtype;
7038   enum tree_code subcode;
7039
7040   /* Don't die if an entire brace-pair level is superfluous
7041      in the containing level.  */
7042   if (constructor_type == 0)
7043     return 1;
7044
7045   /* If there were errors in this designator list already, bail out
7046      silently.  */
7047   if (designator_erroneous)
7048     return 1;
7049
7050   if (!designator_depth)
7051     {
7052       gcc_assert (!constructor_range_stack);
7053
7054       /* Designator list starts at the level of closest explicit
7055          braces.  */
7056       while (constructor_stack->implicit)
7057         {
7058           process_init_element (pop_init_level (1, braced_init_obstack),
7059                                 true, braced_init_obstack);
7060         }
7061       constructor_designated = 1;
7062       return 0;
7063     }
7064
7065   switch (TREE_CODE (constructor_type))
7066     {
7067     case  RECORD_TYPE:
7068     case  UNION_TYPE:
7069       subtype = TREE_TYPE (constructor_fields);
7070       if (subtype != error_mark_node)
7071         subtype = TYPE_MAIN_VARIANT (subtype);
7072       break;
7073     case ARRAY_TYPE:
7074       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7075       break;
7076     default:
7077       gcc_unreachable ();
7078     }
7079
7080   subcode = TREE_CODE (subtype);
7081   if (array && subcode != ARRAY_TYPE)
7082     {
7083       error_init ("array index in non-array initializer");
7084       return 1;
7085     }
7086   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
7087     {
7088       error_init ("field name not in record or union initializer");
7089       return 1;
7090     }
7091
7092   constructor_designated = 1;
7093   push_init_level (2, braced_init_obstack);
7094   return 0;
7095 }
7096
7097 /* If there are range designators in designator list, push a new designator
7098    to constructor_range_stack.  RANGE_END is end of such stack range or
7099    NULL_TREE if there is no range designator at this level.  */
7100
7101 static void
7102 push_range_stack (tree range_end, struct obstack * braced_init_obstack)
7103 {
7104   struct constructor_range_stack *p;
7105
7106   p = (struct constructor_range_stack *)
7107     obstack_alloc (braced_init_obstack,
7108                    sizeof (struct constructor_range_stack));
7109   p->prev = constructor_range_stack;
7110   p->next = 0;
7111   p->fields = constructor_fields;
7112   p->range_start = constructor_index;
7113   p->index = constructor_index;
7114   p->stack = constructor_stack;
7115   p->range_end = range_end;
7116   if (constructor_range_stack)
7117     constructor_range_stack->next = p;
7118   constructor_range_stack = p;
7119 }
7120
7121 /* Within an array initializer, specify the next index to be initialized.
7122    FIRST is that index.  If LAST is nonzero, then initialize a range
7123    of indices, running from FIRST through LAST.  */
7124
7125 void
7126 set_init_index (tree first, tree last,
7127                 struct obstack * braced_init_obstack)
7128 {
7129   if (set_designator (1, braced_init_obstack))
7130     return;
7131
7132   designator_erroneous = 1;
7133
7134   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
7135       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
7136     {
7137       error_init ("array index in initializer not of integer type");
7138       return;
7139     }
7140
7141   if (TREE_CODE (first) != INTEGER_CST)
7142     {
7143       first = c_fully_fold (first, false, NULL);
7144       if (TREE_CODE (first) == INTEGER_CST)
7145         pedwarn_init (input_location, OPT_pedantic,
7146                       "array index in initializer is not "
7147                       "an integer constant expression");
7148     }
7149
7150   if (last && TREE_CODE (last) != INTEGER_CST)
7151     {
7152       last = c_fully_fold (last, false, NULL);
7153       if (TREE_CODE (last) == INTEGER_CST)
7154         pedwarn_init (input_location, OPT_pedantic,
7155                       "array index in initializer is not "
7156                       "an integer constant expression");
7157     }
7158
7159   if (TREE_CODE (first) != INTEGER_CST)
7160     error_init ("nonconstant array index in initializer");
7161   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
7162     error_init ("nonconstant array index in initializer");
7163   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
7164     error_init ("array index in non-array initializer");
7165   else if (tree_int_cst_sgn (first) == -1)
7166     error_init ("array index in initializer exceeds array bounds");
7167   else if (constructor_max_index
7168            && tree_int_cst_lt (constructor_max_index, first))
7169     error_init ("array index in initializer exceeds array bounds");
7170   else
7171     {
7172       constant_expression_warning (first);
7173       if (last)
7174         constant_expression_warning (last);
7175       constructor_index = convert (bitsizetype, first);
7176
7177       if (last)
7178         {
7179           if (tree_int_cst_equal (first, last))
7180             last = 0;
7181           else if (tree_int_cst_lt (last, first))
7182             {
7183               error_init ("empty index range in initializer");
7184               last = 0;
7185             }
7186           else
7187             {
7188               last = convert (bitsizetype, last);
7189               if (constructor_max_index != 0
7190                   && tree_int_cst_lt (constructor_max_index, last))
7191                 {
7192                   error_init ("array index range in initializer exceeds array bounds");
7193                   last = 0;
7194                 }
7195             }
7196         }
7197
7198       designator_depth++;
7199       designator_erroneous = 0;
7200       if (constructor_range_stack || last)
7201         push_range_stack (last, braced_init_obstack);
7202     }
7203 }
7204
7205 /* Within a struct initializer, specify the next field to be initialized.  */
7206
7207 void
7208 set_init_label (tree fieldname, struct obstack * braced_init_obstack)
7209 {
7210   tree field;
7211
7212   if (set_designator (0, braced_init_obstack))
7213     return;
7214
7215   designator_erroneous = 1;
7216
7217   if (TREE_CODE (constructor_type) != RECORD_TYPE
7218       && TREE_CODE (constructor_type) != UNION_TYPE)
7219     {
7220       error_init ("field name not in record or union initializer");
7221       return;
7222     }
7223
7224   field = lookup_field (constructor_type, fieldname);
7225
7226   if (field == 0)
7227     error ("unknown field %qE specified in initializer", fieldname);
7228   else
7229     do
7230       {
7231         constructor_fields = TREE_VALUE (field);
7232         designator_depth++;
7233         designator_erroneous = 0;
7234         if (constructor_range_stack)
7235           push_range_stack (NULL_TREE, braced_init_obstack);
7236         field = TREE_CHAIN (field);
7237         if (field)
7238           {
7239             if (set_designator (0, braced_init_obstack))
7240               return;
7241           }
7242       }
7243     while (field != NULL_TREE);
7244 }
7245 \f
7246 /* Add a new initializer to the tree of pending initializers.  PURPOSE
7247    identifies the initializer, either array index or field in a structure.
7248    VALUE is the value of that index or field.  If ORIGTYPE is not
7249    NULL_TREE, it is the original type of VALUE.
7250
7251    IMPLICIT is true if value comes from pop_init_level (1),
7252    the new initializer has been merged with the existing one
7253    and thus no warnings should be emitted about overriding an
7254    existing initializer.  */
7255
7256 static void
7257 add_pending_init (tree purpose, tree value, tree origtype, bool implicit,
7258                   struct obstack * braced_init_obstack)
7259 {
7260   struct init_node *p, **q, *r;
7261
7262   q = &constructor_pending_elts;
7263   p = 0;
7264
7265   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7266     {
7267       while (*q != 0)
7268         {
7269           p = *q;
7270           if (tree_int_cst_lt (purpose, p->purpose))
7271             q = &p->left;
7272           else if (tree_int_cst_lt (p->purpose, purpose))
7273             q = &p->right;
7274           else
7275             {
7276               if (!implicit)
7277                 {
7278                   if (TREE_SIDE_EFFECTS (p->value))
7279                     warning_init (0, "initialized field with side-effects overwritten");
7280                   else if (warn_override_init)
7281                     warning_init (OPT_Woverride_init, "initialized field overwritten");
7282                 }
7283               p->value = value;
7284               p->origtype = origtype;
7285               return;
7286             }
7287         }
7288     }
7289   else
7290     {
7291       tree bitpos;
7292
7293       bitpos = bit_position (purpose);
7294       while (*q != NULL)
7295         {
7296           p = *q;
7297           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7298             q = &p->left;
7299           else if (p->purpose != purpose)
7300             q = &p->right;
7301           else
7302             {
7303               if (!implicit)
7304                 {
7305                   if (TREE_SIDE_EFFECTS (p->value))
7306                     warning_init (0, "initialized field with side-effects overwritten");
7307                   else if (warn_override_init)
7308                     warning_init (OPT_Woverride_init, "initialized field overwritten");
7309                 }
7310               p->value = value;
7311               p->origtype = origtype;
7312               return;
7313             }
7314         }
7315     }
7316
7317   r = (struct init_node *) obstack_alloc (braced_init_obstack,
7318                                           sizeof (struct init_node));
7319   r->purpose = purpose;
7320   r->value = value;
7321   r->origtype = origtype;
7322
7323   *q = r;
7324   r->parent = p;
7325   r->left = 0;
7326   r->right = 0;
7327   r->balance = 0;
7328
7329   while (p)
7330     {
7331       struct init_node *s;
7332
7333       if (r == p->left)
7334         {
7335           if (p->balance == 0)
7336             p->balance = -1;
7337           else if (p->balance < 0)
7338             {
7339               if (r->balance < 0)
7340                 {
7341                   /* L rotation.  */
7342                   p->left = r->right;
7343                   if (p->left)
7344                     p->left->parent = p;
7345                   r->right = p;
7346
7347                   p->balance = 0;
7348                   r->balance = 0;
7349
7350                   s = p->parent;
7351                   p->parent = r;
7352                   r->parent = s;
7353                   if (s)
7354                     {
7355                       if (s->left == p)
7356                         s->left = r;
7357                       else
7358                         s->right = r;
7359                     }
7360                   else
7361                     constructor_pending_elts = r;
7362                 }
7363               else
7364                 {
7365                   /* LR rotation.  */
7366                   struct init_node *t = r->right;
7367
7368                   r->right = t->left;
7369                   if (r->right)
7370                     r->right->parent = r;
7371                   t->left = r;
7372
7373                   p->left = t->right;
7374                   if (p->left)
7375                     p->left->parent = p;
7376                   t->right = p;
7377
7378                   p->balance = t->balance < 0;
7379                   r->balance = -(t->balance > 0);
7380                   t->balance = 0;
7381
7382                   s = p->parent;
7383                   p->parent = t;
7384                   r->parent = t;
7385                   t->parent = s;
7386                   if (s)
7387                     {
7388                       if (s->left == p)
7389                         s->left = t;
7390                       else
7391                         s->right = t;
7392                     }
7393                   else
7394                     constructor_pending_elts = t;
7395                 }
7396               break;
7397             }
7398           else
7399             {
7400               /* p->balance == +1; growth of left side balances the node.  */
7401               p->balance = 0;
7402               break;
7403             }
7404         }
7405       else /* r == p->right */
7406         {
7407           if (p->balance == 0)
7408             /* Growth propagation from right side.  */
7409             p->balance++;
7410           else if (p->balance > 0)
7411             {
7412               if (r->balance > 0)
7413                 {
7414                   /* R rotation.  */
7415                   p->right = r->left;
7416                   if (p->right)
7417                     p->right->parent = p;
7418                   r->left = p;
7419
7420                   p->balance = 0;
7421                   r->balance = 0;
7422
7423                   s = p->parent;
7424                   p->parent = r;
7425                   r->parent = s;
7426                   if (s)
7427                     {
7428                       if (s->left == p)
7429                         s->left = r;
7430                       else
7431                         s->right = r;
7432                     }
7433                   else
7434                     constructor_pending_elts = r;
7435                 }
7436               else /* r->balance == -1 */
7437                 {
7438                   /* RL rotation */
7439                   struct init_node *t = r->left;
7440
7441                   r->left = t->right;
7442                   if (r->left)
7443                     r->left->parent = r;
7444                   t->right = r;
7445
7446                   p->right = t->left;
7447                   if (p->right)
7448                     p->right->parent = p;
7449                   t->left = p;
7450
7451                   r->balance = (t->balance < 0);
7452                   p->balance = -(t->balance > 0);
7453                   t->balance = 0;
7454
7455                   s = p->parent;
7456                   p->parent = t;
7457                   r->parent = t;
7458                   t->parent = s;
7459                   if (s)
7460                     {
7461                       if (s->left == p)
7462                         s->left = t;
7463                       else
7464                         s->right = t;
7465                     }
7466                   else
7467                     constructor_pending_elts = t;
7468                 }
7469               break;
7470             }
7471           else
7472             {
7473               /* p->balance == -1; growth of right side balances the node.  */
7474               p->balance = 0;
7475               break;
7476             }
7477         }
7478
7479       r = p;
7480       p = p->parent;
7481     }
7482 }
7483
7484 /* Build AVL tree from a sorted chain.  */
7485
7486 static void
7487 set_nonincremental_init (struct obstack * braced_init_obstack)
7488 {
7489   unsigned HOST_WIDE_INT ix;
7490   tree index, value;
7491
7492   if (TREE_CODE (constructor_type) != RECORD_TYPE
7493       && TREE_CODE (constructor_type) != ARRAY_TYPE)
7494     return;
7495
7496   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
7497     {
7498       add_pending_init (index, value, NULL_TREE, false,
7499                         braced_init_obstack);
7500     }
7501   constructor_elements = 0;
7502   if (TREE_CODE (constructor_type) == RECORD_TYPE)
7503     {
7504       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
7505       /* Skip any nameless bit fields at the beginning.  */
7506       while (constructor_unfilled_fields != 0
7507              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7508              && DECL_NAME (constructor_unfilled_fields) == 0)
7509         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
7510
7511     }
7512   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7513     {
7514       if (TYPE_DOMAIN (constructor_type))
7515         constructor_unfilled_index
7516             = convert (bitsizetype,
7517                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
7518       else
7519         constructor_unfilled_index = bitsize_zero_node;
7520     }
7521   constructor_incremental = 0;
7522 }
7523
7524 /* Build AVL tree from a string constant.  */
7525
7526 static void
7527 set_nonincremental_init_from_string (tree str,
7528                                      struct obstack * braced_init_obstack)
7529 {
7530   tree value, purpose, type;
7531   HOST_WIDE_INT val[2];
7532   const char *p, *end;
7533   int byte, wchar_bytes, charwidth, bitpos;
7534
7535   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7536
7537   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7538   charwidth = TYPE_PRECISION (char_type_node);
7539   type = TREE_TYPE (constructor_type);
7540   p = TREE_STRING_POINTER (str);
7541   end = p + TREE_STRING_LENGTH (str);
7542
7543   for (purpose = bitsize_zero_node;
7544        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7545        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7546     {
7547       if (wchar_bytes == 1)
7548         {
7549           val[1] = (unsigned char) *p++;
7550           val[0] = 0;
7551         }
7552       else
7553         {
7554           val[0] = 0;
7555           val[1] = 0;
7556           for (byte = 0; byte < wchar_bytes; byte++)
7557             {
7558               if (BYTES_BIG_ENDIAN)
7559                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7560               else
7561                 bitpos = byte * charwidth;
7562               val[bitpos < HOST_BITS_PER_WIDE_INT]
7563                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7564                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7565             }
7566         }
7567
7568       if (!TYPE_UNSIGNED (type))
7569         {
7570           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7571           if (bitpos < HOST_BITS_PER_WIDE_INT)
7572             {
7573               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7574                 {
7575                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7576                   val[0] = -1;
7577                 }
7578             }
7579           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7580             {
7581               if (val[1] < 0)
7582                 val[0] = -1;
7583             }
7584           else if (val[0] & (((HOST_WIDE_INT) 1)
7585                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7586             val[0] |= ((HOST_WIDE_INT) -1)
7587                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7588         }
7589
7590       value = build_int_cst_wide (type, val[1], val[0]);
7591       add_pending_init (purpose, value, NULL_TREE, false,
7592                         braced_init_obstack);
7593     }
7594
7595   constructor_incremental = 0;
7596 }
7597
7598 /* Return value of FIELD in pending initializer or zero if the field was
7599    not initialized yet.  */
7600
7601 static tree
7602 find_init_member (tree field, struct obstack * braced_init_obstack)
7603 {
7604   struct init_node *p;
7605
7606   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7607     {
7608       if (constructor_incremental
7609           && tree_int_cst_lt (field, constructor_unfilled_index))
7610         set_nonincremental_init (braced_init_obstack);
7611
7612       p = constructor_pending_elts;
7613       while (p)
7614         {
7615           if (tree_int_cst_lt (field, p->purpose))
7616             p = p->left;
7617           else if (tree_int_cst_lt (p->purpose, field))
7618             p = p->right;
7619           else
7620             return p->value;
7621         }
7622     }
7623   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7624     {
7625       tree bitpos = bit_position (field);
7626
7627       if (constructor_incremental
7628           && (!constructor_unfilled_fields
7629               || tree_int_cst_lt (bitpos,
7630                                   bit_position (constructor_unfilled_fields))))
7631         set_nonincremental_init (braced_init_obstack);
7632
7633       p = constructor_pending_elts;
7634       while (p)
7635         {
7636           if (field == p->purpose)
7637             return p->value;
7638           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7639             p = p->left;
7640           else
7641             p = p->right;
7642         }
7643     }
7644   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7645     {
7646       if (!VEC_empty (constructor_elt, constructor_elements)
7647           && (VEC_last (constructor_elt, constructor_elements)->index
7648               == field))
7649         return VEC_last (constructor_elt, constructor_elements)->value;
7650     }
7651   return 0;
7652 }
7653
7654 /* "Output" the next constructor element.
7655    At top level, really output it to assembler code now.
7656    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7657    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7658    TYPE is the data type that the containing data type wants here.
7659    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7660    If VALUE is a string constant, STRICT_STRING is true if it is
7661    unparenthesized or we should not warn here for it being parenthesized.
7662    For other types of VALUE, STRICT_STRING is not used.
7663
7664    PENDING if non-nil means output pending elements that belong
7665    right after this element.  (PENDING is normally 1;
7666    it is 0 while outputting pending elements, to avoid recursion.)
7667
7668    IMPLICIT is true if value comes from pop_init_level (1),
7669    the new initializer has been merged with the existing one
7670    and thus no warnings should be emitted about overriding an
7671    existing initializer.  */
7672
7673 static void
7674 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7675                      tree field, int pending, bool implicit,
7676                      struct obstack * braced_init_obstack)
7677 {
7678   tree semantic_type = NULL_TREE;
7679   constructor_elt *celt;
7680   bool maybe_const = true;
7681   bool npc;
7682
7683   if (type == error_mark_node || value == error_mark_node)
7684     {
7685       constructor_erroneous = 1;
7686       return;
7687     }
7688   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7689       && (TREE_CODE (value) == STRING_CST
7690           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7691       && !(TREE_CODE (value) == STRING_CST
7692            && TREE_CODE (type) == ARRAY_TYPE
7693            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7694       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7695                      TYPE_MAIN_VARIANT (type)))
7696     value = array_to_pointer_conversion (input_location, value);
7697
7698   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7699       && require_constant_value && !flag_isoc99 && pending)
7700     {
7701       /* As an extension, allow initializing objects with static storage
7702          duration with compound literals (which are then treated just as
7703          the brace enclosed list they contain).  */
7704       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7705       value = DECL_INITIAL (decl);
7706     }
7707
7708   npc = null_pointer_constant_p (value);
7709   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7710     {
7711       semantic_type = TREE_TYPE (value);
7712       value = TREE_OPERAND (value, 0);
7713     }
7714   value = c_fully_fold (value, require_constant_value, &maybe_const);
7715
7716   if (value == error_mark_node)
7717     constructor_erroneous = 1;
7718   else if (!TREE_CONSTANT (value))
7719     constructor_constant = 0;
7720   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7721            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7722                 || TREE_CODE (constructor_type) == UNION_TYPE)
7723                && DECL_C_BIT_FIELD (field)
7724                && TREE_CODE (value) != INTEGER_CST))
7725     constructor_simple = 0;
7726   if (!maybe_const)
7727     constructor_nonconst = 1;
7728
7729   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7730     {
7731       if (require_constant_value)
7732         {
7733           error_init ("initializer element is not constant");
7734           value = error_mark_node;
7735         }
7736       else if (require_constant_elements)
7737         pedwarn (input_location, 0,
7738                  "initializer element is not computable at load time");
7739     }
7740   else if (!maybe_const
7741            && (require_constant_value || require_constant_elements))
7742     pedwarn_init (input_location, 0,
7743                   "initializer element is not a constant expression");
7744
7745   /* Issue -Wc++-compat warnings about initializing a bitfield with
7746      enum type.  */
7747   if (warn_cxx_compat
7748       && field != NULL_TREE
7749       && TREE_CODE (field) == FIELD_DECL
7750       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7751       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7752           != TYPE_MAIN_VARIANT (type))
7753       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7754     {
7755       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7756       if (checktype != error_mark_node
7757           && (TYPE_MAIN_VARIANT (checktype)
7758               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7759         warning_init (OPT_Wc___compat,
7760                       "enum conversion in initialization is invalid in C++");
7761     }
7762
7763   /* If this field is empty (and not at the end of structure),
7764      don't do anything other than checking the initializer.  */
7765   if (field
7766       && (TREE_TYPE (field) == error_mark_node
7767           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7768               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7769               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7770                   || DECL_CHAIN (field)))))
7771     return;
7772
7773   if (semantic_type)
7774     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7775   value = digest_init (input_location, type, value, origtype, npc,
7776                        strict_string, require_constant_value);
7777   if (value == error_mark_node)
7778     {
7779       constructor_erroneous = 1;
7780       return;
7781     }
7782   if (require_constant_value || require_constant_elements)
7783     constant_expression_warning (value);
7784
7785   /* If this element doesn't come next in sequence,
7786      put it on constructor_pending_elts.  */
7787   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7788       && (!constructor_incremental
7789           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7790     {
7791       if (constructor_incremental
7792           && tree_int_cst_lt (field, constructor_unfilled_index))
7793         set_nonincremental_init (braced_init_obstack);
7794
7795       add_pending_init (field, value, origtype, implicit,
7796                         braced_init_obstack);
7797       return;
7798     }
7799   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7800            && (!constructor_incremental
7801                || field != constructor_unfilled_fields))
7802     {
7803       /* We do this for records but not for unions.  In a union,
7804          no matter which field is specified, it can be initialized
7805          right away since it starts at the beginning of the union.  */
7806       if (constructor_incremental)
7807         {
7808           if (!constructor_unfilled_fields)
7809             set_nonincremental_init (braced_init_obstack);
7810           else
7811             {
7812               tree bitpos, unfillpos;
7813
7814               bitpos = bit_position (field);
7815               unfillpos = bit_position (constructor_unfilled_fields);
7816
7817               if (tree_int_cst_lt (bitpos, unfillpos))
7818                 set_nonincremental_init (braced_init_obstack);
7819             }
7820         }
7821
7822       add_pending_init (field, value, origtype, implicit,
7823                         braced_init_obstack);
7824       return;
7825     }
7826   else if (TREE_CODE (constructor_type) == UNION_TYPE
7827            && !VEC_empty (constructor_elt, constructor_elements))
7828     {
7829       if (!implicit)
7830         {
7831           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7832                                            constructor_elements)->value))
7833             warning_init (0,
7834                           "initialized field with side-effects overwritten");
7835           else if (warn_override_init)
7836             warning_init (OPT_Woverride_init, "initialized field overwritten");
7837         }
7838
7839       /* We can have just one union field set.  */
7840       constructor_elements = 0;
7841     }
7842
7843   /* Otherwise, output this element either to
7844      constructor_elements or to the assembler file.  */
7845
7846   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7847   celt->index = field;
7848   celt->value = value;
7849
7850   /* Advance the variable that indicates sequential elements output.  */
7851   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7852     constructor_unfilled_index
7853       = size_binop_loc (input_location, PLUS_EXPR, constructor_unfilled_index,
7854                         bitsize_one_node);
7855   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7856     {
7857       constructor_unfilled_fields
7858         = DECL_CHAIN (constructor_unfilled_fields);
7859
7860       /* Skip any nameless bit fields.  */
7861       while (constructor_unfilled_fields != 0
7862              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7863              && DECL_NAME (constructor_unfilled_fields) == 0)
7864         constructor_unfilled_fields =
7865           DECL_CHAIN (constructor_unfilled_fields);
7866     }
7867   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7868     constructor_unfilled_fields = 0;
7869
7870   /* Now output any pending elements which have become next.  */
7871   if (pending)
7872     output_pending_init_elements (0, braced_init_obstack);
7873 }
7874
7875 /* Output any pending elements which have become next.
7876    As we output elements, constructor_unfilled_{fields,index}
7877    advances, which may cause other elements to become next;
7878    if so, they too are output.
7879
7880    If ALL is 0, we return when there are
7881    no more pending elements to output now.
7882
7883    If ALL is 1, we output space as necessary so that
7884    we can output all the pending elements.  */
7885 static void
7886 output_pending_init_elements (int all, struct obstack * braced_init_obstack)
7887 {
7888   struct init_node *elt = constructor_pending_elts;
7889   tree next;
7890
7891  retry:
7892
7893   /* Look through the whole pending tree.
7894      If we find an element that should be output now,
7895      output it.  Otherwise, set NEXT to the element
7896      that comes first among those still pending.  */
7897
7898   next = 0;
7899   while (elt)
7900     {
7901       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7902         {
7903           if (tree_int_cst_equal (elt->purpose,
7904                                   constructor_unfilled_index))
7905             output_init_element (elt->value, elt->origtype, true,
7906                                  TREE_TYPE (constructor_type),
7907                                  constructor_unfilled_index, 0, false,
7908                                  braced_init_obstack);
7909           else if (tree_int_cst_lt (constructor_unfilled_index,
7910                                     elt->purpose))
7911             {
7912               /* Advance to the next smaller node.  */
7913               if (elt->left)
7914                 elt = elt->left;
7915               else
7916                 {
7917                   /* We have reached the smallest node bigger than the
7918                      current unfilled index.  Fill the space first.  */
7919                   next = elt->purpose;
7920                   break;
7921                 }
7922             }
7923           else
7924             {
7925               /* Advance to the next bigger node.  */
7926               if (elt->right)
7927                 elt = elt->right;
7928               else
7929                 {
7930                   /* We have reached the biggest node in a subtree.  Find
7931                      the parent of it, which is the next bigger node.  */
7932                   while (elt->parent && elt->parent->right == elt)
7933                     elt = elt->parent;
7934                   elt = elt->parent;
7935                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7936                                               elt->purpose))
7937                     {
7938                       next = elt->purpose;
7939                       break;
7940                     }
7941                 }
7942             }
7943         }
7944       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7945                || TREE_CODE (constructor_type) == UNION_TYPE)
7946         {
7947           tree ctor_unfilled_bitpos, elt_bitpos;
7948
7949           /* If the current record is complete we are done.  */
7950           if (constructor_unfilled_fields == 0)
7951             break;
7952
7953           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7954           elt_bitpos = bit_position (elt->purpose);
7955           /* We can't compare fields here because there might be empty
7956              fields in between.  */
7957           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7958             {
7959               constructor_unfilled_fields = elt->purpose;
7960               output_init_element (elt->value, elt->origtype, true,
7961                                    TREE_TYPE (elt->purpose),
7962                                    elt->purpose, 0, false,
7963                                    braced_init_obstack);
7964             }
7965           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7966             {
7967               /* Advance to the next smaller node.  */
7968               if (elt->left)
7969                 elt = elt->left;
7970               else
7971                 {
7972                   /* We have reached the smallest node bigger than the
7973                      current unfilled field.  Fill the space first.  */
7974                   next = elt->purpose;
7975                   break;
7976                 }
7977             }
7978           else
7979             {
7980               /* Advance to the next bigger node.  */
7981               if (elt->right)
7982                 elt = elt->right;
7983               else
7984                 {
7985                   /* We have reached the biggest node in a subtree.  Find
7986                      the parent of it, which is the next bigger node.  */
7987                   while (elt->parent && elt->parent->right == elt)
7988                     elt = elt->parent;
7989                   elt = elt->parent;
7990                   if (elt
7991                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7992                                            bit_position (elt->purpose))))
7993                     {
7994                       next = elt->purpose;
7995                       break;
7996                     }
7997                 }
7998             }
7999         }
8000     }
8001
8002   /* Ordinarily return, but not if we want to output all
8003      and there are elements left.  */
8004   if (!(all && next != 0))
8005     return;
8006
8007   /* If it's not incremental, just skip over the gap, so that after
8008      jumping to retry we will output the next successive element.  */
8009   if (TREE_CODE (constructor_type) == RECORD_TYPE
8010       || TREE_CODE (constructor_type) == UNION_TYPE)
8011     constructor_unfilled_fields = next;
8012   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
8013     constructor_unfilled_index = next;
8014
8015   /* ELT now points to the node in the pending tree with the next
8016      initializer to output.  */
8017   goto retry;
8018 }
8019 \f
8020 /* Add one non-braced element to the current constructor level.
8021    This adjusts the current position within the constructor's type.
8022    This may also start or terminate implicit levels
8023    to handle a partly-braced initializer.
8024
8025    Once this has found the correct level for the new element,
8026    it calls output_init_element.
8027
8028    IMPLICIT is true if value comes from pop_init_level (1),
8029    the new initializer has been merged with the existing one
8030    and thus no warnings should be emitted about overriding an
8031    existing initializer.  */
8032
8033 void
8034 process_init_element (struct c_expr value, bool implicit,
8035                       struct obstack * braced_init_obstack)
8036 {
8037   tree orig_value = value.value;
8038   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
8039   bool strict_string = value.original_code == STRING_CST;
8040
8041   designator_depth = 0;
8042   designator_erroneous = 0;
8043
8044   /* Handle superfluous braces around string cst as in
8045      char x[] = {"foo"}; */
8046   if (string_flag
8047       && constructor_type
8048       && TREE_CODE (constructor_type) == ARRAY_TYPE
8049       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
8050       && integer_zerop (constructor_unfilled_index))
8051     {
8052       if (constructor_stack->replacement_value.value)
8053         error_init ("excess elements in char array initializer");
8054       constructor_stack->replacement_value = value;
8055       return;
8056     }
8057
8058   if (constructor_stack->replacement_value.value != 0)
8059     {
8060       error_init ("excess elements in struct initializer");
8061       return;
8062     }
8063
8064   /* Ignore elements of a brace group if it is entirely superfluous
8065      and has already been diagnosed.  */
8066   if (constructor_type == 0)
8067     return;
8068
8069   /* If we've exhausted any levels that didn't have braces,
8070      pop them now.  */
8071   while (constructor_stack->implicit)
8072     {
8073       if ((TREE_CODE (constructor_type) == RECORD_TYPE
8074            || TREE_CODE (constructor_type) == UNION_TYPE)
8075           && constructor_fields == 0)
8076         process_init_element (pop_init_level (1, braced_init_obstack),
8077                               true, braced_init_obstack);
8078       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
8079                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
8080                && (constructor_max_index == 0
8081                    || tree_int_cst_lt (constructor_max_index,
8082                                        constructor_index)))
8083         process_init_element (pop_init_level (1, braced_init_obstack),
8084                               true, braced_init_obstack);
8085       else
8086         break;
8087     }
8088
8089   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
8090   if (constructor_range_stack)
8091     {
8092       /* If value is a compound literal and we'll be just using its
8093          content, don't put it into a SAVE_EXPR.  */
8094       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
8095           || !require_constant_value
8096           || flag_isoc99)
8097         {
8098           tree semantic_type = NULL_TREE;
8099           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
8100             {
8101               semantic_type = TREE_TYPE (value.value);
8102               value.value = TREE_OPERAND (value.value, 0);
8103             }
8104           value.value = c_save_expr (value.value);
8105           if (semantic_type)
8106             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
8107                                   value.value);
8108         }
8109     }
8110
8111   while (1)
8112     {
8113       if (TREE_CODE (constructor_type) == RECORD_TYPE)
8114         {
8115           tree fieldtype;
8116           enum tree_code fieldcode;
8117
8118           if (constructor_fields == 0)
8119             {
8120               pedwarn_init (input_location, 0,
8121                             "excess elements in struct initializer");
8122               break;
8123             }
8124
8125           fieldtype = TREE_TYPE (constructor_fields);
8126           if (fieldtype != error_mark_node)
8127             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
8128           fieldcode = TREE_CODE (fieldtype);
8129
8130           /* Error for non-static initialization of a flexible array member.  */
8131           if (fieldcode == ARRAY_TYPE
8132               && !require_constant_value
8133               && TYPE_SIZE (fieldtype) == NULL_TREE
8134               && DECL_CHAIN (constructor_fields) == NULL_TREE)
8135             {
8136               error_init ("non-static initialization of a flexible array member");
8137               break;
8138             }
8139
8140           /* Accept a string constant to initialize a subarray.  */
8141           if (value.value != 0
8142               && fieldcode == ARRAY_TYPE
8143               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
8144               && string_flag)
8145             value.value = orig_value;
8146           /* Otherwise, if we have come to a subaggregate,
8147              and we don't have an element of its type, push into it.  */
8148           else if (value.value != 0
8149                    && value.value != error_mark_node
8150                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
8151                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
8152                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
8153             {
8154               push_init_level (1, braced_init_obstack);
8155               continue;
8156             }
8157
8158           if (value.value)
8159             {
8160               push_member_name (constructor_fields);
8161               output_init_element (value.value, value.original_type,
8162                                    strict_string, fieldtype,
8163                                    constructor_fields, 1, implicit,
8164                                    braced_init_obstack);
8165               RESTORE_SPELLING_DEPTH (constructor_depth);
8166             }
8167           else
8168             /* Do the bookkeeping for an element that was
8169                directly output as a constructor.  */
8170             {
8171               /* For a record, keep track of end position of last field.  */
8172               if (DECL_SIZE (constructor_fields))
8173                 constructor_bit_index
8174                   = size_binop_loc (input_location, PLUS_EXPR,
8175                                     bit_position (constructor_fields),
8176                                     DECL_SIZE (constructor_fields));
8177
8178               /* If the current field was the first one not yet written out,
8179                  it isn't now, so update.  */
8180               if (constructor_unfilled_fields == constructor_fields)
8181                 {
8182                   constructor_unfilled_fields = DECL_CHAIN (constructor_fields);
8183                   /* Skip any nameless bit fields.  */
8184                   while (constructor_unfilled_fields != 0
8185                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
8186                          && DECL_NAME (constructor_unfilled_fields) == 0)
8187                     constructor_unfilled_fields =
8188                       DECL_CHAIN (constructor_unfilled_fields);
8189                 }
8190             }
8191
8192           constructor_fields = DECL_CHAIN (constructor_fields);
8193           /* Skip any nameless bit fields at the beginning.  */
8194           while (constructor_fields != 0
8195                  && DECL_C_BIT_FIELD (constructor_fields)
8196                  && DECL_NAME (constructor_fields) == 0)
8197             constructor_fields = DECL_CHAIN (constructor_fields);
8198         }
8199       else if (TREE_CODE (constructor_type) == UNION_TYPE)
8200         {
8201           tree fieldtype;
8202           enum tree_code fieldcode;
8203
8204           if (constructor_fields == 0)
8205             {
8206               pedwarn_init (input_location, 0,
8207                             "excess elements in union initializer");
8208               break;
8209             }
8210
8211           fieldtype = TREE_TYPE (constructor_fields);
8212           if (fieldtype != error_mark_node)
8213             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
8214           fieldcode = TREE_CODE (fieldtype);
8215
8216           /* Warn that traditional C rejects initialization of unions.
8217              We skip the warning if the value is zero.  This is done
8218              under the assumption that the zero initializer in user
8219              code appears conditioned on e.g. __STDC__ to avoid
8220              "missing initializer" warnings and relies on default
8221              initialization to zero in the traditional C case.
8222              We also skip the warning if the initializer is designated,
8223              again on the assumption that this must be conditional on
8224              __STDC__ anyway (and we've already complained about the
8225              member-designator already).  */
8226           if (!in_system_header && !constructor_designated
8227               && !(value.value && (integer_zerop (value.value)
8228                                    || real_zerop (value.value))))
8229             warning (OPT_Wtraditional, "traditional C rejects initialization "
8230                      "of unions");
8231
8232           /* Accept a string constant to initialize a subarray.  */
8233           if (value.value != 0
8234               && fieldcode == ARRAY_TYPE
8235               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
8236               && string_flag)
8237             value.value = orig_value;
8238           /* Otherwise, if we have come to a subaggregate,
8239              and we don't have an element of its type, push into it.  */
8240           else if (value.value != 0
8241                    && value.value != error_mark_node
8242                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
8243                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
8244                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
8245             {
8246               push_init_level (1, braced_init_obstack);
8247               continue;
8248             }
8249
8250           if (value.value)
8251             {
8252               push_member_name (constructor_fields);
8253               output_init_element (value.value, value.original_type,
8254                                    strict_string, fieldtype,
8255                                    constructor_fields, 1, implicit,
8256                                    braced_init_obstack);
8257               RESTORE_SPELLING_DEPTH (constructor_depth);
8258             }
8259           else
8260             /* Do the bookkeeping for an element that was
8261                directly output as a constructor.  */
8262             {
8263               constructor_bit_index = DECL_SIZE (constructor_fields);
8264               constructor_unfilled_fields = DECL_CHAIN (constructor_fields);
8265             }
8266
8267           constructor_fields = 0;
8268         }
8269       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
8270         {
8271           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
8272           enum tree_code eltcode = TREE_CODE (elttype);
8273
8274           /* Accept a string constant to initialize a subarray.  */
8275           if (value.value != 0
8276               && eltcode == ARRAY_TYPE
8277               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
8278               && string_flag)
8279             value.value = orig_value;
8280           /* Otherwise, if we have come to a subaggregate,
8281              and we don't have an element of its type, push into it.  */
8282           else if (value.value != 0
8283                    && value.value != error_mark_node
8284                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
8285                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
8286                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
8287             {
8288               push_init_level (1, braced_init_obstack);
8289               continue;
8290             }
8291
8292           if (constructor_max_index != 0
8293               && (tree_int_cst_lt (constructor_max_index, constructor_index)
8294                   || integer_all_onesp (constructor_max_index)))
8295             {
8296               pedwarn_init (input_location, 0,
8297                             "excess elements in array initializer");
8298               break;
8299             }
8300
8301           /* Now output the actual element.  */
8302           if (value.value)
8303             {
8304               push_array_bounds (tree_low_cst (constructor_index, 1));
8305               output_init_element (value.value, value.original_type,
8306                                    strict_string, elttype,
8307                                    constructor_index, 1, implicit,
8308                                    braced_init_obstack);
8309               RESTORE_SPELLING_DEPTH (constructor_depth);
8310             }
8311
8312           constructor_index
8313             = size_binop_loc (input_location, PLUS_EXPR,
8314                               constructor_index, bitsize_one_node);
8315
8316           if (!value.value)
8317             /* If we are doing the bookkeeping for an element that was
8318                directly output as a constructor, we must update
8319                constructor_unfilled_index.  */
8320             constructor_unfilled_index = constructor_index;
8321         }
8322       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
8323         {
8324           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
8325
8326          /* Do a basic check of initializer size.  Note that vectors
8327             always have a fixed size derived from their type.  */
8328           if (tree_int_cst_lt (constructor_max_index, constructor_index))
8329             {
8330               pedwarn_init (input_location, 0,
8331                             "excess elements in vector initializer");
8332               break;
8333             }
8334
8335           /* Now output the actual element.  */
8336           if (value.value)
8337             {
8338               if (TREE_CODE (value.value) == VECTOR_CST)
8339                 elttype = TYPE_MAIN_VARIANT (constructor_type);
8340               output_init_element (value.value, value.original_type,
8341                                    strict_string, elttype,
8342                                    constructor_index, 1, implicit,
8343                                    braced_init_obstack);
8344             }
8345
8346           constructor_index
8347             = size_binop_loc (input_location,
8348                               PLUS_EXPR, constructor_index, bitsize_one_node);
8349
8350           if (!value.value)
8351             /* If we are doing the bookkeeping for an element that was
8352                directly output as a constructor, we must update
8353                constructor_unfilled_index.  */
8354             constructor_unfilled_index = constructor_index;
8355         }
8356
8357       /* Handle the sole element allowed in a braced initializer
8358          for a scalar variable.  */
8359       else if (constructor_type != error_mark_node
8360                && constructor_fields == 0)
8361         {
8362           pedwarn_init (input_location, 0,
8363                         "excess elements in scalar initializer");
8364           break;
8365         }
8366       else
8367         {
8368           if (value.value)
8369             output_init_element (value.value, value.original_type,
8370                                  strict_string, constructor_type,
8371                                  NULL_TREE, 1, implicit,
8372                                  braced_init_obstack);
8373           constructor_fields = 0;
8374         }
8375
8376       /* Handle range initializers either at this level or anywhere higher
8377          in the designator stack.  */
8378       if (constructor_range_stack)
8379         {
8380           struct constructor_range_stack *p, *range_stack;
8381           int finish = 0;
8382
8383           range_stack = constructor_range_stack;
8384           constructor_range_stack = 0;
8385           while (constructor_stack != range_stack->stack)
8386             {
8387               gcc_assert (constructor_stack->implicit);
8388               process_init_element (pop_init_level (1,
8389                                                     braced_init_obstack),
8390                                     true, braced_init_obstack);
8391             }
8392           for (p = range_stack;
8393                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
8394                p = p->prev)
8395             {
8396               gcc_assert (constructor_stack->implicit);
8397               process_init_element (pop_init_level (1, braced_init_obstack),
8398                                     true, braced_init_obstack);
8399             }
8400
8401           p->index = size_binop_loc (input_location,
8402                                      PLUS_EXPR, p->index, bitsize_one_node);
8403           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
8404             finish = 1;
8405
8406           while (1)
8407             {
8408               constructor_index = p->index;
8409               constructor_fields = p->fields;
8410               if (finish && p->range_end && p->index == p->range_start)
8411                 {
8412                   finish = 0;
8413                   p->prev = 0;
8414                 }
8415               p = p->next;
8416               if (!p)
8417                 break;
8418               push_init_level (2, braced_init_obstack);
8419               p->stack = constructor_stack;
8420               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
8421                 p->index = p->range_start;
8422             }
8423
8424           if (!finish)
8425             constructor_range_stack = range_stack;
8426           continue;
8427         }
8428
8429       break;
8430     }
8431
8432   constructor_range_stack = 0;
8433 }
8434 \f
8435 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
8436    (guaranteed to be 'volatile' or null) and ARGS (represented using
8437    an ASM_EXPR node).  */
8438 tree
8439 build_asm_stmt (tree cv_qualifier, tree args)
8440 {
8441   if (!ASM_VOLATILE_P (args) && cv_qualifier)
8442     ASM_VOLATILE_P (args) = 1;
8443   return add_stmt (args);
8444 }
8445
8446 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
8447    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
8448    SIMPLE indicates whether there was anything at all after the
8449    string in the asm expression -- asm("blah") and asm("blah" : )
8450    are subtly different.  We use a ASM_EXPR node to represent this.  */
8451 tree
8452 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
8453                 tree clobbers, tree labels, bool simple)
8454 {
8455   tree tail;
8456   tree args;
8457   int i;
8458   const char *constraint;
8459   const char **oconstraints;
8460   bool allows_mem, allows_reg, is_inout;
8461   int ninputs, noutputs;
8462
8463   ninputs = list_length (inputs);
8464   noutputs = list_length (outputs);
8465   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
8466
8467   string = resolve_asm_operand_names (string, outputs, inputs, labels);
8468
8469   /* Remove output conversions that change the type but not the mode.  */
8470   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
8471     {
8472       tree output = TREE_VALUE (tail);
8473
8474       /* ??? Really, this should not be here.  Users should be using a
8475          proper lvalue, dammit.  But there's a long history of using casts
8476          in the output operands.  In cases like longlong.h, this becomes a
8477          primitive form of typechecking -- if the cast can be removed, then
8478          the output operand had a type of the proper width; otherwise we'll
8479          get an error.  Gross, but ...  */
8480       STRIP_NOPS (output);
8481
8482       if (!lvalue_or_else (output, lv_asm))
8483         output = error_mark_node;
8484
8485       if (output != error_mark_node
8486           && (TREE_READONLY (output)
8487               || TYPE_READONLY (TREE_TYPE (output))
8488               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
8489                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
8490                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
8491         readonly_error (output, lv_asm);
8492
8493       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8494       oconstraints[i] = constraint;
8495
8496       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
8497                                    &allows_mem, &allows_reg, &is_inout))
8498         {
8499           /* If the operand is going to end up in memory,
8500              mark it addressable.  */
8501           if (!allows_reg && !c_mark_addressable (output))
8502             output = error_mark_node;
8503         }
8504       else
8505         output = error_mark_node;
8506
8507       TREE_VALUE (tail) = output;
8508     }
8509
8510   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
8511     {
8512       tree input;
8513
8514       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8515       input = TREE_VALUE (tail);
8516
8517       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
8518                                   oconstraints, &allows_mem, &allows_reg))
8519         {
8520           /* If the operand is going to end up in memory,
8521              mark it addressable.  */
8522           if (!allows_reg && allows_mem)
8523             {
8524               /* Strip the nops as we allow this case.  FIXME, this really
8525                  should be rejected or made deprecated.  */
8526               STRIP_NOPS (input);
8527               if (!c_mark_addressable (input))
8528                 input = error_mark_node;
8529           }
8530         }
8531       else
8532         input = error_mark_node;
8533
8534       TREE_VALUE (tail) = input;
8535     }
8536
8537   /* ASMs with labels cannot have outputs.  This should have been
8538      enforced by the parser.  */
8539   gcc_assert (outputs == NULL || labels == NULL);
8540
8541   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers, labels);
8542
8543   /* asm statements without outputs, including simple ones, are treated
8544      as volatile.  */
8545   ASM_INPUT_P (args) = simple;
8546   ASM_VOLATILE_P (args) = (noutputs == 0);
8547
8548   return args;
8549 }
8550 \f
8551 /* Generate a goto statement to LABEL.  LOC is the location of the
8552    GOTO.  */
8553
8554 tree
8555 c_finish_goto_label (location_t loc, tree label)
8556 {
8557   tree decl = lookup_label_for_goto (loc, label);
8558   if (!decl)
8559     return NULL_TREE;
8560   TREE_USED (decl) = 1;
8561   {
8562     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8563     SET_EXPR_LOCATION (t, loc);
8564     return add_stmt (t);
8565   }
8566 }
8567
8568 /* Generate a computed goto statement to EXPR.  LOC is the location of
8569    the GOTO.  */
8570
8571 tree
8572 c_finish_goto_ptr (location_t loc, tree expr)
8573 {
8574   tree t;
8575   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8576   expr = c_fully_fold (expr, false, NULL);
8577   expr = convert (ptr_type_node, expr);
8578   t = build1 (GOTO_EXPR, void_type_node, expr);
8579   SET_EXPR_LOCATION (t, loc);
8580   return add_stmt (t);
8581 }
8582
8583 /* Generate a C `return' statement.  RETVAL is the expression for what
8584    to return, or a null pointer for `return;' with no value.  LOC is
8585    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8586    is the original type of RETVAL.  */
8587
8588 tree
8589 c_finish_return (location_t loc, tree retval, tree origtype)
8590 {
8591   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8592   bool no_warning = false;
8593   bool npc = false;
8594
8595   if (TREE_THIS_VOLATILE (current_function_decl))
8596     warning_at (loc, 0,
8597                 "function declared %<noreturn%> has a %<return%> statement");
8598
8599   if (retval)
8600     {
8601       tree semantic_type = NULL_TREE;
8602       npc = null_pointer_constant_p (retval);
8603       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8604         {
8605           semantic_type = TREE_TYPE (retval);
8606           retval = TREE_OPERAND (retval, 0);
8607         }
8608       retval = c_fully_fold (retval, false, NULL);
8609       if (semantic_type)
8610         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8611     }
8612
8613   if (!retval)
8614     {
8615       current_function_returns_null = 1;
8616       if ((warn_return_type || flag_isoc99)
8617           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8618         {
8619           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8620                        "%<return%> with no value, in "
8621                        "function returning non-void");
8622           no_warning = true;
8623         }
8624     }
8625   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8626     {
8627       current_function_returns_null = 1;
8628       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8629         pedwarn (loc, 0,
8630                  "%<return%> with a value, in function returning void");
8631       else
8632         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8633                  "%<return%> with expression, in function returning void");
8634     }
8635   else
8636     {
8637       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8638                                        ic_return,
8639                                        npc, NULL_TREE, NULL_TREE, 0);
8640       tree res = DECL_RESULT (current_function_decl);
8641       tree inner;
8642
8643       current_function_returns_value = 1;
8644       if (t == error_mark_node)
8645         return NULL_TREE;
8646
8647       inner = t = convert (TREE_TYPE (res), t);
8648
8649       /* Strip any conversions, additions, and subtractions, and see if
8650          we are returning the address of a local variable.  Warn if so.  */
8651       while (1)
8652         {
8653           switch (TREE_CODE (inner))
8654             {
8655             CASE_CONVERT:
8656             case NON_LVALUE_EXPR:
8657             case PLUS_EXPR:
8658             case POINTER_PLUS_EXPR:
8659               inner = TREE_OPERAND (inner, 0);
8660               continue;
8661
8662             case MINUS_EXPR:
8663               /* If the second operand of the MINUS_EXPR has a pointer
8664                  type (or is converted from it), this may be valid, so
8665                  don't give a warning.  */
8666               {
8667                 tree op1 = TREE_OPERAND (inner, 1);
8668
8669                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8670                        && (CONVERT_EXPR_P (op1)
8671                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8672                   op1 = TREE_OPERAND (op1, 0);
8673
8674                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8675                   break;
8676
8677                 inner = TREE_OPERAND (inner, 0);
8678                 continue;
8679               }
8680
8681             case ADDR_EXPR:
8682               inner = TREE_OPERAND (inner, 0);
8683
8684               while (REFERENCE_CLASS_P (inner)
8685                      && TREE_CODE (inner) != INDIRECT_REF)
8686                 inner = TREE_OPERAND (inner, 0);
8687
8688               if (DECL_P (inner)
8689                   && !DECL_EXTERNAL (inner)
8690                   && !TREE_STATIC (inner)
8691                   && DECL_CONTEXT (inner) == current_function_decl)
8692                 warning_at (loc,
8693                             0, "function returns address of local variable");
8694               break;
8695
8696             default:
8697               break;
8698             }
8699
8700           break;
8701         }
8702
8703       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8704       SET_EXPR_LOCATION (retval, loc);
8705
8706       if (warn_sequence_point)
8707         verify_sequence_points (retval);
8708     }
8709
8710   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8711   TREE_NO_WARNING (ret_stmt) |= no_warning;
8712   return add_stmt (ret_stmt);
8713 }
8714 \f
8715 struct c_switch {
8716   /* The SWITCH_EXPR being built.  */
8717   tree switch_expr;
8718
8719   /* The original type of the testing expression, i.e. before the
8720      default conversion is applied.  */
8721   tree orig_type;
8722
8723   /* A splay-tree mapping the low element of a case range to the high
8724      element, or NULL_TREE if there is no high element.  Used to
8725      determine whether or not a new case label duplicates an old case
8726      label.  We need a tree, rather than simply a hash table, because
8727      of the GNU case range extension.  */
8728   splay_tree cases;
8729
8730   /* The bindings at the point of the switch.  This is used for
8731      warnings crossing decls when branching to a case label.  */
8732   struct c_spot_bindings *bindings;
8733
8734   /* The next node on the stack.  */
8735   struct c_switch *next;
8736 };
8737
8738 /* A stack of the currently active switch statements.  The innermost
8739    switch statement is on the top of the stack.  There is no need to
8740    mark the stack for garbage collection because it is only active
8741    during the processing of the body of a function, and we never
8742    collect at that point.  */
8743
8744 struct c_switch *c_switch_stack;
8745
8746 /* Start a C switch statement, testing expression EXP.  Return the new
8747    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8748    SWITCH_COND_LOC is the location of the switch's condition.  */
8749
8750 tree
8751 c_start_case (location_t switch_loc,
8752               location_t switch_cond_loc,
8753               tree exp)
8754 {
8755   tree orig_type = error_mark_node;
8756   struct c_switch *cs;
8757
8758   if (exp != error_mark_node)
8759     {
8760       orig_type = TREE_TYPE (exp);
8761
8762       if (!INTEGRAL_TYPE_P (orig_type))
8763         {
8764           if (orig_type != error_mark_node)
8765             {
8766               error_at (switch_cond_loc, "switch quantity not an integer");
8767               orig_type = error_mark_node;
8768             }
8769           exp = integer_zero_node;
8770         }
8771       else
8772         {
8773           tree type = TYPE_MAIN_VARIANT (orig_type);
8774
8775           if (!in_system_header
8776               && (type == long_integer_type_node
8777                   || type == long_unsigned_type_node))
8778             warning_at (switch_cond_loc,
8779                         OPT_Wtraditional, "%<long%> switch expression not "
8780                         "converted to %<int%> in ISO C");
8781
8782           exp = c_fully_fold (exp, false, NULL);
8783           exp = default_conversion (exp);
8784
8785           if (warn_sequence_point)
8786             verify_sequence_points (exp);
8787         }
8788     }
8789
8790   /* Add this new SWITCH_EXPR to the stack.  */
8791   cs = XNEW (struct c_switch);
8792   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8793   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8794   cs->orig_type = orig_type;
8795   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8796   cs->bindings = c_get_switch_bindings ();
8797   cs->next = c_switch_stack;
8798   c_switch_stack = cs;
8799
8800   return add_stmt (cs->switch_expr);
8801 }
8802
8803 /* Process a case label at location LOC.  */
8804
8805 tree
8806 do_case (location_t loc, tree low_value, tree high_value)
8807 {
8808   tree label = NULL_TREE;
8809
8810   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8811     {
8812       low_value = c_fully_fold (low_value, false, NULL);
8813       if (TREE_CODE (low_value) == INTEGER_CST)
8814         pedwarn (input_location, OPT_pedantic,
8815                  "case label is not an integer constant expression");
8816     }
8817
8818   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8819     {
8820       high_value = c_fully_fold (high_value, false, NULL);
8821       if (TREE_CODE (high_value) == INTEGER_CST)
8822         pedwarn (input_location, OPT_pedantic,
8823                  "case label is not an integer constant expression");
8824     }
8825
8826   if (c_switch_stack == NULL)
8827     {
8828       if (low_value)
8829         error_at (loc, "case label not within a switch statement");
8830       else
8831         error_at (loc, "%<default%> label not within a switch statement");
8832       return NULL_TREE;
8833     }
8834
8835   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8836                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8837                                     loc))
8838     return NULL_TREE;
8839
8840   label = c_add_case_label (loc, c_switch_stack->cases,
8841                             SWITCH_COND (c_switch_stack->switch_expr),
8842                             c_switch_stack->orig_type,
8843                             low_value, high_value);
8844   if (label == error_mark_node)
8845     label = NULL_TREE;
8846   return label;
8847 }
8848
8849 /* Finish the switch statement.  */
8850
8851 void
8852 c_finish_case (tree body)
8853 {
8854   struct c_switch *cs = c_switch_stack;
8855   location_t switch_location;
8856
8857   SWITCH_BODY (cs->switch_expr) = body;
8858
8859   /* Emit warnings as needed.  */
8860   switch_location = EXPR_LOCATION (cs->switch_expr);
8861   c_do_switch_warnings (cs->cases, switch_location,
8862                         TREE_TYPE (cs->switch_expr),
8863                         SWITCH_COND (cs->switch_expr));
8864
8865   /* Pop the stack.  */
8866   c_switch_stack = cs->next;
8867   splay_tree_delete (cs->cases);
8868   c_release_switch_bindings (cs->bindings);
8869   XDELETE (cs);
8870 }
8871 \f
8872 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8873    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8874    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8875    statement, and was not surrounded with parenthesis.  */
8876
8877 void
8878 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8879                   tree else_block, bool nested_if)
8880 {
8881   tree stmt;
8882
8883   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8884   if (warn_parentheses && nested_if && else_block == NULL)
8885     {
8886       tree inner_if = then_block;
8887
8888       /* We know from the grammar productions that there is an IF nested
8889          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8890          it might not be exactly THEN_BLOCK, but should be the last
8891          non-container statement within.  */
8892       while (1)
8893         switch (TREE_CODE (inner_if))
8894           {
8895           case COND_EXPR:
8896             goto found;
8897           case BIND_EXPR:
8898             inner_if = BIND_EXPR_BODY (inner_if);
8899             break;
8900           case STATEMENT_LIST:
8901             inner_if = expr_last (then_block);
8902             break;
8903           case TRY_FINALLY_EXPR:
8904           case TRY_CATCH_EXPR:
8905             inner_if = TREE_OPERAND (inner_if, 0);
8906             break;
8907           default:
8908             gcc_unreachable ();
8909           }
8910     found:
8911
8912       if (COND_EXPR_ELSE (inner_if))
8913          warning_at (if_locus, OPT_Wparentheses,
8914                      "suggest explicit braces to avoid ambiguous %<else%>");
8915     }
8916
8917   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8918   SET_EXPR_LOCATION (stmt, if_locus);
8919   add_stmt (stmt);
8920 }
8921
8922 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8923    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8924    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8925    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8926    the continue label.  Everything is allowed to be NULL.  */
8927
8928 void
8929 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8930                tree blab, tree clab, bool cond_is_first)
8931 {
8932   tree entry = NULL, exit = NULL, t;
8933
8934   /* If the condition is zero don't generate a loop construct.  */
8935   if (cond && integer_zerop (cond))
8936     {
8937       if (cond_is_first)
8938         {
8939           t = build_and_jump (&blab);
8940           SET_EXPR_LOCATION (t, start_locus);
8941           add_stmt (t);
8942         }
8943     }
8944   else
8945     {
8946       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8947
8948       /* If we have an exit condition, then we build an IF with gotos either
8949          out of the loop, or to the top of it.  If there's no exit condition,
8950          then we just build a jump back to the top.  */
8951       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8952
8953       if (cond && !integer_nonzerop (cond))
8954         {
8955           /* Canonicalize the loop condition to the end.  This means
8956              generating a branch to the loop condition.  Reuse the
8957              continue label, if possible.  */
8958           if (cond_is_first)
8959             {
8960               if (incr || !clab)
8961                 {
8962                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8963                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8964                 }
8965               else
8966                 t = build1 (GOTO_EXPR, void_type_node, clab);
8967               SET_EXPR_LOCATION (t, start_locus);
8968               add_stmt (t);
8969             }
8970
8971           t = build_and_jump (&blab);
8972           if (cond_is_first)
8973             exit = fold_build3_loc (start_locus,
8974                                 COND_EXPR, void_type_node, cond, exit, t);
8975           else
8976             exit = fold_build3_loc (input_location,
8977                                 COND_EXPR, void_type_node, cond, exit, t);
8978         }
8979
8980       add_stmt (top);
8981     }
8982
8983   if (body)
8984     add_stmt (body);
8985   if (clab)
8986     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8987   if (incr)
8988     add_stmt (incr);
8989   if (entry)
8990     add_stmt (entry);
8991   if (exit)
8992     add_stmt (exit);
8993   if (blab)
8994     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8995 }
8996
8997 tree
8998 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
8999 {
9000   bool skip;
9001   tree label = *label_p;
9002
9003   /* In switch statements break is sometimes stylistically used after
9004      a return statement.  This can lead to spurious warnings about
9005      control reaching the end of a non-void function when it is
9006      inlined.  Note that we are calling block_may_fallthru with
9007      language specific tree nodes; this works because
9008      block_may_fallthru returns true when given something it does not
9009      understand.  */
9010   skip = !block_may_fallthru (cur_stmt_list);
9011
9012   if (!label)
9013     {
9014       if (!skip)
9015         *label_p = label = create_artificial_label (loc);
9016     }
9017   else if (TREE_CODE (label) == LABEL_DECL)
9018     ;
9019   else switch (TREE_INT_CST_LOW (label))
9020     {
9021     case 0:
9022       if (is_break)
9023         error_at (loc, "break statement not within loop or switch");
9024       else
9025         error_at (loc, "continue statement not within a loop");
9026       return NULL_TREE;
9027
9028     case 1:
9029       gcc_assert (is_break);
9030       error_at (loc, "break statement used with OpenMP for loop");
9031       return NULL_TREE;
9032
9033     default:
9034       gcc_unreachable ();
9035     }
9036
9037   if (skip)
9038     return NULL_TREE;
9039
9040   if (!is_break)
9041     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
9042
9043   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
9044 }
9045
9046 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
9047
9048 static void
9049 emit_side_effect_warnings (location_t loc, tree expr)
9050 {
9051   if (expr == error_mark_node)
9052     ;
9053   else if (!TREE_SIDE_EFFECTS (expr))
9054     {
9055       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
9056         warning_at (loc, OPT_Wunused_value, "statement with no effect");
9057     }
9058   else
9059     warn_if_unused_value (expr, loc);
9060 }
9061
9062 /* Process an expression as if it were a complete statement.  Emit
9063    diagnostics, but do not call ADD_STMT.  LOC is the location of the
9064    statement.  */
9065
9066 tree
9067 c_process_expr_stmt (location_t loc, tree expr)
9068 {
9069   tree exprv;
9070
9071   if (!expr)
9072     return NULL_TREE;
9073
9074   expr = c_fully_fold (expr, false, NULL);
9075
9076   if (warn_sequence_point)
9077     verify_sequence_points (expr);
9078
9079   if (TREE_TYPE (expr) != error_mark_node
9080       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
9081       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
9082     error_at (loc, "expression statement has incomplete type");
9083
9084   /* If we're not processing a statement expression, warn about unused values.
9085      Warnings for statement expressions will be emitted later, once we figure
9086      out which is the result.  */
9087   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
9088       && warn_unused_value)
9089     emit_side_effect_warnings (loc, expr);
9090
9091   exprv = expr;
9092   while (TREE_CODE (exprv) == COMPOUND_EXPR)
9093     exprv = TREE_OPERAND (exprv, 1);
9094   if (DECL_P (exprv) || handled_component_p (exprv))
9095     mark_exp_read (exprv);
9096
9097   /* If the expression is not of a type to which we cannot assign a line
9098      number, wrap the thing in a no-op NOP_EXPR.  */
9099   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
9100     {
9101       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9102       SET_EXPR_LOCATION (expr, loc);
9103     }
9104
9105   return expr;
9106 }
9107
9108 /* Emit an expression as a statement.  LOC is the location of the
9109    expression.  */
9110
9111 tree
9112 c_finish_expr_stmt (location_t loc, tree expr)
9113 {
9114   if (expr)
9115     return add_stmt (c_process_expr_stmt (loc, expr));
9116   else
9117     return NULL;
9118 }
9119
9120 /* Do the opposite and emit a statement as an expression.  To begin,
9121    create a new binding level and return it.  */
9122
9123 tree
9124 c_begin_stmt_expr (void)
9125 {
9126   tree ret;
9127
9128   /* We must force a BLOCK for this level so that, if it is not expanded
9129      later, there is a way to turn off the entire subtree of blocks that
9130      are contained in it.  */
9131   keep_next_level ();
9132   ret = c_begin_compound_stmt (true);
9133
9134   c_bindings_start_stmt_expr (c_switch_stack == NULL
9135                               ? NULL
9136                               : c_switch_stack->bindings);
9137
9138   /* Mark the current statement list as belonging to a statement list.  */
9139   STATEMENT_LIST_STMT_EXPR (ret) = 1;
9140
9141   return ret;
9142 }
9143
9144 /* LOC is the location of the compound statement to which this body
9145    belongs.  */
9146
9147 tree
9148 c_finish_stmt_expr (location_t loc, tree body)
9149 {
9150   tree last, type, tmp, val;
9151   tree *last_p;
9152
9153   body = c_end_compound_stmt (loc, body, true);
9154
9155   c_bindings_end_stmt_expr (c_switch_stack == NULL
9156                             ? NULL
9157                             : c_switch_stack->bindings);
9158
9159   /* Locate the last statement in BODY.  See c_end_compound_stmt
9160      about always returning a BIND_EXPR.  */
9161   last_p = &BIND_EXPR_BODY (body);
9162   last = BIND_EXPR_BODY (body);
9163
9164  continue_searching:
9165   if (TREE_CODE (last) == STATEMENT_LIST)
9166     {
9167       tree_stmt_iterator i;
9168
9169       /* This can happen with degenerate cases like ({ }).  No value.  */
9170       if (!TREE_SIDE_EFFECTS (last))
9171         return body;
9172
9173       /* If we're supposed to generate side effects warnings, process
9174          all of the statements except the last.  */
9175       if (warn_unused_value)
9176         {
9177           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
9178             {
9179               location_t tloc;
9180               tree t = tsi_stmt (i);
9181
9182               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
9183               emit_side_effect_warnings (tloc, t);
9184             }
9185         }
9186       else
9187         i = tsi_last (last);
9188       last_p = tsi_stmt_ptr (i);
9189       last = *last_p;
9190     }
9191
9192   /* If the end of the list is exception related, then the list was split
9193      by a call to push_cleanup.  Continue searching.  */
9194   if (TREE_CODE (last) == TRY_FINALLY_EXPR
9195       || TREE_CODE (last) == TRY_CATCH_EXPR)
9196     {
9197       last_p = &TREE_OPERAND (last, 0);
9198       last = *last_p;
9199       goto continue_searching;
9200     }
9201
9202   if (last == error_mark_node)
9203     return last;
9204
9205   /* In the case that the BIND_EXPR is not necessary, return the
9206      expression out from inside it.  */
9207   if (last == BIND_EXPR_BODY (body)
9208       && BIND_EXPR_VARS (body) == NULL)
9209     {
9210       /* Even if this looks constant, do not allow it in a constant
9211          expression.  */
9212       last = c_wrap_maybe_const (last, true);
9213       /* Do not warn if the return value of a statement expression is
9214          unused.  */
9215       TREE_NO_WARNING (last) = 1;
9216       return last;
9217     }
9218
9219   /* Extract the type of said expression.  */
9220   type = TREE_TYPE (last);
9221
9222   /* If we're not returning a value at all, then the BIND_EXPR that
9223      we already have is a fine expression to return.  */
9224   if (!type || VOID_TYPE_P (type))
9225     return body;
9226
9227   /* Now that we've located the expression containing the value, it seems
9228      silly to make voidify_wrapper_expr repeat the process.  Create a
9229      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
9230   tmp = create_tmp_var_raw (type, NULL);
9231
9232   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
9233      tree_expr_nonnegative_p giving up immediately.  */
9234   val = last;
9235   if (TREE_CODE (val) == NOP_EXPR
9236       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
9237     val = TREE_OPERAND (val, 0);
9238
9239   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
9240   SET_EXPR_LOCATION (*last_p, EXPR_LOCATION (last));
9241
9242   {
9243     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
9244     SET_EXPR_LOCATION (t, loc);
9245     return t;
9246   }
9247 }
9248 \f
9249 /* Begin and end compound statements.  This is as simple as pushing
9250    and popping new statement lists from the tree.  */
9251
9252 tree
9253 c_begin_compound_stmt (bool do_scope)
9254 {
9255   tree stmt = push_stmt_list ();
9256   if (do_scope)
9257     push_scope ();
9258   return stmt;
9259 }
9260
9261 /* End a compound statement.  STMT is the statement.  LOC is the
9262    location of the compound statement-- this is usually the location
9263    of the opening brace.  */
9264
9265 tree
9266 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
9267 {
9268   tree block = NULL;
9269
9270   if (do_scope)
9271     {
9272       if (c_dialect_objc ())
9273         objc_clear_super_receiver ();
9274       block = pop_scope ();
9275     }
9276
9277   stmt = pop_stmt_list (stmt);
9278   stmt = c_build_bind_expr (loc, block, stmt);
9279
9280   /* If this compound statement is nested immediately inside a statement
9281      expression, then force a BIND_EXPR to be created.  Otherwise we'll
9282      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
9283      STATEMENT_LISTs merge, and thus we can lose track of what statement
9284      was really last.  */
9285   if (cur_stmt_list
9286       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
9287       && TREE_CODE (stmt) != BIND_EXPR)
9288     {
9289       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
9290       TREE_SIDE_EFFECTS (stmt) = 1;
9291       SET_EXPR_LOCATION (stmt, loc);
9292     }
9293
9294   return stmt;
9295 }
9296
9297 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
9298    when the current scope is exited.  EH_ONLY is true when this is not
9299    meant to apply to normal control flow transfer.  */
9300
9301 void
9302 push_cleanup (tree decl, tree cleanup, bool eh_only)
9303 {
9304   enum tree_code code;
9305   tree stmt, list;
9306   bool stmt_expr;
9307
9308   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
9309   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
9310   add_stmt (stmt);
9311   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
9312   list = push_stmt_list ();
9313   TREE_OPERAND (stmt, 0) = list;
9314   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
9315 }
9316 \f
9317 /* Build a binary-operation expression without default conversions.
9318    CODE is the kind of expression to build.
9319    LOCATION is the operator's location.
9320    This function differs from `build' in several ways:
9321    the data type of the result is computed and recorded in it,
9322    warnings are generated if arg data types are invalid,
9323    special handling for addition and subtraction of pointers is known,
9324    and some optimization is done (operations on narrow ints
9325    are done in the narrower type when that gives the same result).
9326    Constant folding is also done before the result is returned.
9327
9328    Note that the operands will never have enumeral types, or function
9329    or array types, because either they will have the default conversions
9330    performed or they have both just been converted to some other type in which
9331    the arithmetic is to be done.  */
9332
9333 tree
9334 build_binary_op (location_t location, enum tree_code code,
9335                  tree orig_op0, tree orig_op1, int convert_p)
9336 {
9337   tree type0, type1, orig_type0, orig_type1;
9338   tree eptype;
9339   enum tree_code code0, code1;
9340   tree op0, op1;
9341   tree ret = error_mark_node;
9342   const char *invalid_op_diag;
9343   bool op0_int_operands, op1_int_operands;
9344   bool int_const, int_const_or_overflow, int_operands;
9345
9346   /* Expression code to give to the expression when it is built.
9347      Normally this is CODE, which is what the caller asked for,
9348      but in some special cases we change it.  */
9349   enum tree_code resultcode = code;
9350
9351   /* Data type in which the computation is to be performed.
9352      In the simplest cases this is the common type of the arguments.  */
9353   tree result_type = NULL;
9354
9355   /* When the computation is in excess precision, the type of the
9356      final EXCESS_PRECISION_EXPR.  */
9357   tree semantic_result_type = NULL;
9358
9359   /* Nonzero means operands have already been type-converted
9360      in whatever way is necessary.
9361      Zero means they need to be converted to RESULT_TYPE.  */
9362   int converted = 0;
9363
9364   /* Nonzero means create the expression with this type, rather than
9365      RESULT_TYPE.  */
9366   tree build_type = 0;
9367
9368   /* Nonzero means after finally constructing the expression
9369      convert it to this type.  */
9370   tree final_type = 0;
9371
9372   /* Nonzero if this is an operation like MIN or MAX which can
9373      safely be computed in short if both args are promoted shorts.
9374      Also implies COMMON.
9375      -1 indicates a bitwise operation; this makes a difference
9376      in the exact conditions for when it is safe to do the operation
9377      in a narrower mode.  */
9378   int shorten = 0;
9379
9380   /* Nonzero if this is a comparison operation;
9381      if both args are promoted shorts, compare the original shorts.
9382      Also implies COMMON.  */
9383   int short_compare = 0;
9384
9385   /* Nonzero if this is a right-shift operation, which can be computed on the
9386      original short and then promoted if the operand is a promoted short.  */
9387   int short_shift = 0;
9388
9389   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
9390   int common = 0;
9391
9392   /* True means types are compatible as far as ObjC is concerned.  */
9393   bool objc_ok;
9394
9395   /* True means this is an arithmetic operation that may need excess
9396      precision.  */
9397   bool may_need_excess_precision;
9398
9399   /* True means this is a boolean operation that converts both its
9400      operands to truth-values.  */
9401   bool boolean_op = false;
9402
9403   if (location == UNKNOWN_LOCATION)
9404     location = input_location;
9405
9406   op0 = orig_op0;
9407   op1 = orig_op1;
9408
9409   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
9410   if (op0_int_operands)
9411     op0 = remove_c_maybe_const_expr (op0);
9412   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
9413   if (op1_int_operands)
9414     op1 = remove_c_maybe_const_expr (op1);
9415   int_operands = (op0_int_operands && op1_int_operands);
9416   if (int_operands)
9417     {
9418       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
9419                                && TREE_CODE (orig_op1) == INTEGER_CST);
9420       int_const = (int_const_or_overflow
9421                    && !TREE_OVERFLOW (orig_op0)
9422                    && !TREE_OVERFLOW (orig_op1));
9423     }
9424   else
9425     int_const = int_const_or_overflow = false;
9426
9427   if (convert_p)
9428     {
9429       op0 = default_conversion (op0);
9430       op1 = default_conversion (op1);
9431     }
9432
9433   orig_type0 = type0 = TREE_TYPE (op0);
9434   orig_type1 = type1 = TREE_TYPE (op1);
9435
9436   /* The expression codes of the data types of the arguments tell us
9437      whether the arguments are integers, floating, pointers, etc.  */
9438   code0 = TREE_CODE (type0);
9439   code1 = TREE_CODE (type1);
9440
9441   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
9442   STRIP_TYPE_NOPS (op0);
9443   STRIP_TYPE_NOPS (op1);
9444
9445   /* If an error was already reported for one of the arguments,
9446      avoid reporting another error.  */
9447
9448   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9449     return error_mark_node;
9450
9451   if ((invalid_op_diag
9452        = targetm.invalid_binary_op (code, type0, type1)))
9453     {
9454       error_at (location, invalid_op_diag);
9455       return error_mark_node;
9456     }
9457
9458   switch (code)
9459     {
9460     case PLUS_EXPR:
9461     case MINUS_EXPR:
9462     case MULT_EXPR:
9463     case TRUNC_DIV_EXPR:
9464     case CEIL_DIV_EXPR:
9465     case FLOOR_DIV_EXPR:
9466     case ROUND_DIV_EXPR:
9467     case EXACT_DIV_EXPR:
9468       may_need_excess_precision = true;
9469       break;
9470     default:
9471       may_need_excess_precision = false;
9472       break;
9473     }
9474   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
9475     {
9476       op0 = TREE_OPERAND (op0, 0);
9477       type0 = TREE_TYPE (op0);
9478     }
9479   else if (may_need_excess_precision
9480            && (eptype = excess_precision_type (type0)) != NULL_TREE)
9481     {
9482       type0 = eptype;
9483       op0 = convert (eptype, op0);
9484     }
9485   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
9486     {
9487       op1 = TREE_OPERAND (op1, 0);
9488       type1 = TREE_TYPE (op1);
9489     }
9490   else if (may_need_excess_precision
9491            && (eptype = excess_precision_type (type1)) != NULL_TREE)
9492     {
9493       type1 = eptype;
9494       op1 = convert (eptype, op1);
9495     }
9496
9497   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
9498
9499   switch (code)
9500     {
9501     case PLUS_EXPR:
9502       /* Handle the pointer + int case.  */
9503       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9504         {
9505           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
9506           goto return_build_binary_op;
9507         }
9508       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
9509         {
9510           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
9511           goto return_build_binary_op;
9512         }
9513       else
9514         common = 1;
9515       break;
9516
9517     case MINUS_EXPR:
9518       /* Subtraction of two similar pointers.
9519          We must subtract them as integers, then divide by object size.  */
9520       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
9521           && comp_target_types (location, type0, type1))
9522         {
9523           ret = pointer_diff (location, op0, op1);
9524           goto return_build_binary_op;
9525         }
9526       /* Handle pointer minus int.  Just like pointer plus int.  */
9527       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9528         {
9529           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
9530           goto return_build_binary_op;
9531         }
9532       else
9533         common = 1;
9534       break;
9535
9536     case MULT_EXPR:
9537       common = 1;
9538       break;
9539
9540     case TRUNC_DIV_EXPR:
9541     case CEIL_DIV_EXPR:
9542     case FLOOR_DIV_EXPR:
9543     case ROUND_DIV_EXPR:
9544     case EXACT_DIV_EXPR:
9545       warn_for_div_by_zero (location, op1);
9546
9547       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9548            || code0 == FIXED_POINT_TYPE
9549            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9550           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9551               || code1 == FIXED_POINT_TYPE
9552               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9553         {
9554           enum tree_code tcode0 = code0, tcode1 = code1;
9555
9556           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9557             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9558           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9559             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9560
9561           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9562               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9563             resultcode = RDIV_EXPR;
9564           else
9565             /* Although it would be tempting to shorten always here, that
9566                loses on some targets, since the modulo instruction is
9567                undefined if the quotient can't be represented in the
9568                computation mode.  We shorten only if unsigned or if
9569                dividing by something we know != -1.  */
9570             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9571                        || (TREE_CODE (op1) == INTEGER_CST
9572                            && !integer_all_onesp (op1)));
9573           common = 1;
9574         }
9575       break;
9576
9577     case BIT_AND_EXPR:
9578     case BIT_IOR_EXPR:
9579     case BIT_XOR_EXPR:
9580       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9581         shorten = -1;
9582       /* Allow vector types which are not floating point types.   */
9583       else if (code0 == VECTOR_TYPE
9584                && code1 == VECTOR_TYPE
9585                && !VECTOR_FLOAT_TYPE_P (type0)
9586                && !VECTOR_FLOAT_TYPE_P (type1))
9587         common = 1;
9588       break;
9589
9590     case TRUNC_MOD_EXPR:
9591     case FLOOR_MOD_EXPR:
9592       warn_for_div_by_zero (location, op1);
9593
9594       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9595           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9596           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9597         common = 1;
9598       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9599         {
9600           /* Although it would be tempting to shorten always here, that loses
9601              on some targets, since the modulo instruction is undefined if the
9602              quotient can't be represented in the computation mode.  We shorten
9603              only if unsigned or if dividing by something we know != -1.  */
9604           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9605                      || (TREE_CODE (op1) == INTEGER_CST
9606                          && !integer_all_onesp (op1)));
9607           common = 1;
9608         }
9609       break;
9610
9611     case TRUTH_ANDIF_EXPR:
9612     case TRUTH_ORIF_EXPR:
9613     case TRUTH_AND_EXPR:
9614     case TRUTH_OR_EXPR:
9615     case TRUTH_XOR_EXPR:
9616       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9617            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9618            || code0 == FIXED_POINT_TYPE)
9619           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9620               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9621               || code1 == FIXED_POINT_TYPE))
9622         {
9623           /* Result of these operations is always an int,
9624              but that does not mean the operands should be
9625              converted to ints!  */
9626           result_type = integer_type_node;
9627           op0 = c_common_truthvalue_conversion (location, op0);
9628           op1 = c_common_truthvalue_conversion (location, op1);
9629           converted = 1;
9630           boolean_op = true;
9631         }
9632       if (code == TRUTH_ANDIF_EXPR)
9633         {
9634           int_const_or_overflow = (int_operands
9635                                    && TREE_CODE (orig_op0) == INTEGER_CST
9636                                    && (op0 == truthvalue_false_node
9637                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9638           int_const = (int_const_or_overflow
9639                        && !TREE_OVERFLOW (orig_op0)
9640                        && (op0 == truthvalue_false_node
9641                            || !TREE_OVERFLOW (orig_op1)));
9642         }
9643       else if (code == TRUTH_ORIF_EXPR)
9644         {
9645           int_const_or_overflow = (int_operands
9646                                    && TREE_CODE (orig_op0) == INTEGER_CST
9647                                    && (op0 == truthvalue_true_node
9648                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9649           int_const = (int_const_or_overflow
9650                        && !TREE_OVERFLOW (orig_op0)
9651                        && (op0 == truthvalue_true_node
9652                            || !TREE_OVERFLOW (orig_op1)));
9653         }
9654       break;
9655
9656       /* Shift operations: result has same type as first operand;
9657          always convert second operand to int.
9658          Also set SHORT_SHIFT if shifting rightward.  */
9659
9660     case RSHIFT_EXPR:
9661       if (code0 == VECTOR_TYPE && code1 == INTEGER_TYPE
9662           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE)
9663         {
9664           result_type = type0;
9665           converted = 1;
9666         }
9667       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9668           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9669           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE
9670           && TYPE_VECTOR_SUBPARTS (type0) == TYPE_VECTOR_SUBPARTS (type1))
9671         {
9672           result_type = type0;
9673           converted = 1;
9674         }
9675       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9676           && code1 == INTEGER_TYPE)
9677         {
9678           if (TREE_CODE (op1) == INTEGER_CST)
9679             {
9680               if (tree_int_cst_sgn (op1) < 0)
9681                 {
9682                   int_const = false;
9683                   if (c_inhibit_evaluation_warnings == 0)
9684                     warning (0, "right shift count is negative");
9685                 }
9686               else
9687                 {
9688                   if (!integer_zerop (op1))
9689                     short_shift = 1;
9690
9691                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9692                     {
9693                       int_const = false;
9694                       if (c_inhibit_evaluation_warnings == 0)
9695                         warning (0, "right shift count >= width of type");
9696                     }
9697                 }
9698             }
9699
9700           /* Use the type of the value to be shifted.  */
9701           result_type = type0;
9702           /* Convert the non vector shift-count to an integer, regardless
9703              of size of value being shifted.  */
9704           if (TREE_CODE (TREE_TYPE (op1)) != VECTOR_TYPE
9705               && TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9706             op1 = convert (integer_type_node, op1);
9707           /* Avoid converting op1 to result_type later.  */
9708           converted = 1;
9709         }
9710       break;
9711
9712     case LSHIFT_EXPR:
9713       if (code0 == VECTOR_TYPE && code1 == INTEGER_TYPE
9714           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE)
9715         {
9716           result_type = type0;
9717           converted = 1;
9718         }
9719       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9720           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9721           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE
9722           && TYPE_VECTOR_SUBPARTS (type0) == TYPE_VECTOR_SUBPARTS (type1))
9723         {
9724           result_type = type0;
9725           converted = 1;
9726         }
9727       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9728           && code1 == INTEGER_TYPE)
9729         {
9730           if (TREE_CODE (op1) == INTEGER_CST)
9731             {
9732               if (tree_int_cst_sgn (op1) < 0)
9733                 {
9734                   int_const = false;
9735                   if (c_inhibit_evaluation_warnings == 0)
9736                     warning (0, "left shift count is negative");
9737                 }
9738
9739               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9740                 {
9741                   int_const = false;
9742                   if (c_inhibit_evaluation_warnings == 0)
9743                     warning (0, "left shift count >= width of type");
9744                 }
9745             }
9746
9747           /* Use the type of the value to be shifted.  */
9748           result_type = type0;
9749           /* Convert the non vector shift-count to an integer, regardless
9750              of size of value being shifted.  */
9751           if (TREE_CODE (TREE_TYPE (op1)) != VECTOR_TYPE
9752               && TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9753             op1 = convert (integer_type_node, op1);
9754           /* Avoid converting op1 to result_type later.  */
9755           converted = 1;
9756         }
9757       break;
9758
9759     case EQ_EXPR:
9760     case NE_EXPR:
9761       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9762         warning_at (location,
9763                     OPT_Wfloat_equal,
9764                     "comparing floating point with == or != is unsafe");
9765       /* Result of comparison is always int,
9766          but don't convert the args to int!  */
9767       build_type = integer_type_node;
9768       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9769            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9770           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9771               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9772         short_compare = 1;
9773       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9774         {
9775           if (TREE_CODE (op0) == ADDR_EXPR
9776               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9777             {
9778               if (code == EQ_EXPR)
9779                 warning_at (location,
9780                             OPT_Waddress,
9781                             "the comparison will always evaluate as %<false%> "
9782                             "for the address of %qD will never be NULL",
9783                             TREE_OPERAND (op0, 0));
9784               else
9785                 warning_at (location,
9786                             OPT_Waddress,
9787                             "the comparison will always evaluate as %<true%> "
9788                             "for the address of %qD will never be NULL",
9789                             TREE_OPERAND (op0, 0));
9790             }
9791           result_type = type0;
9792         }
9793       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9794         {
9795           if (TREE_CODE (op1) == ADDR_EXPR
9796               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9797             {
9798               if (code == EQ_EXPR)
9799                 warning_at (location,
9800                             OPT_Waddress,
9801                             "the comparison will always evaluate as %<false%> "
9802                             "for the address of %qD will never be NULL",
9803                             TREE_OPERAND (op1, 0));
9804               else
9805                 warning_at (location,
9806                             OPT_Waddress,
9807                             "the comparison will always evaluate as %<true%> "
9808                             "for the address of %qD will never be NULL",
9809                             TREE_OPERAND (op1, 0));
9810             }
9811           result_type = type1;
9812         }
9813       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9814         {
9815           tree tt0 = TREE_TYPE (type0);
9816           tree tt1 = TREE_TYPE (type1);
9817           addr_space_t as0 = TYPE_ADDR_SPACE (tt0);
9818           addr_space_t as1 = TYPE_ADDR_SPACE (tt1);
9819           addr_space_t as_common = ADDR_SPACE_GENERIC;
9820
9821           /* Anything compares with void *.  void * compares with anything.
9822              Otherwise, the targets must be compatible
9823              and both must be object or both incomplete.  */
9824           if (comp_target_types (location, type0, type1))
9825             result_type = common_pointer_type (type0, type1);
9826           else if (!addr_space_superset (as0, as1, &as_common))
9827             {
9828               error_at (location, "comparison of pointers to "
9829                         "disjoint address spaces");
9830               return error_mark_node;
9831             }
9832           else if (VOID_TYPE_P (tt0))
9833             {
9834               if (pedantic && TREE_CODE (tt1) == FUNCTION_TYPE)
9835                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9836                          "comparison of %<void *%> with function pointer");
9837             }
9838           else if (VOID_TYPE_P (tt1))
9839             {
9840               if (pedantic && TREE_CODE (tt0) == FUNCTION_TYPE)
9841                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9842                          "comparison of %<void *%> with function pointer");
9843             }
9844           else
9845             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9846             if (!objc_ok)
9847               pedwarn (location, 0,
9848                        "comparison of distinct pointer types lacks a cast");
9849
9850           if (result_type == NULL_TREE)
9851             {
9852               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9853               result_type = build_pointer_type
9854                               (build_qualified_type (void_type_node, qual));
9855             }
9856         }
9857       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9858         {
9859           result_type = type0;
9860           pedwarn (location, 0, "comparison between pointer and integer");
9861         }
9862       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9863         {
9864           result_type = type1;
9865           pedwarn (location, 0, "comparison between pointer and integer");
9866         }
9867       break;
9868
9869     case LE_EXPR:
9870     case GE_EXPR:
9871     case LT_EXPR:
9872     case GT_EXPR:
9873       build_type = integer_type_node;
9874       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9875            || code0 == FIXED_POINT_TYPE)
9876           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9877               || code1 == FIXED_POINT_TYPE))
9878         short_compare = 1;
9879       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9880         {
9881           addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (type0));
9882           addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
9883           addr_space_t as_common;
9884
9885           if (comp_target_types (location, type0, type1))
9886             {
9887               result_type = common_pointer_type (type0, type1);
9888               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9889                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9890                 pedwarn (location, 0,
9891                          "comparison of complete and incomplete pointers");
9892               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9893                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9894                          "ordered comparisons of pointers to functions");
9895               else if (null_pointer_constant_p (orig_op0)
9896                        || null_pointer_constant_p (orig_op1))
9897                 warning_at (location, OPT_Wextra,
9898                             "ordered comparison of pointer with null pointer");
9899
9900             }
9901           else if (!addr_space_superset (as0, as1, &as_common))
9902             {
9903               error_at (location, "comparison of pointers to "
9904                         "disjoint address spaces");
9905               return error_mark_node;
9906             }
9907           else
9908             {
9909               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9910               result_type = build_pointer_type
9911                               (build_qualified_type (void_type_node, qual));
9912               pedwarn (location, 0,
9913                        "comparison of distinct pointer types lacks a cast");
9914             }
9915         }
9916       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9917         {
9918           result_type = type0;
9919           if (pedantic)
9920             pedwarn (location, OPT_pedantic,
9921                      "ordered comparison of pointer with integer zero");
9922           else if (extra_warnings)
9923             warning_at (location, OPT_Wextra,
9924                         "ordered comparison of pointer with integer zero");
9925         }
9926       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9927         {
9928           result_type = type1;
9929           if (pedantic)
9930             pedwarn (location, OPT_pedantic,
9931                      "ordered comparison of pointer with integer zero");
9932           else if (extra_warnings)
9933             warning_at (location, OPT_Wextra,
9934                         "ordered comparison of pointer with integer zero");
9935         }
9936       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9937         {
9938           result_type = type0;
9939           pedwarn (location, 0, "comparison between pointer and integer");
9940         }
9941       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9942         {
9943           result_type = type1;
9944           pedwarn (location, 0, "comparison between pointer and integer");
9945         }
9946       break;
9947
9948     default:
9949       gcc_unreachable ();
9950     }
9951
9952   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9953     return error_mark_node;
9954
9955   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9956       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9957           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9958                                                     TREE_TYPE (type1))))
9959     {
9960       binary_op_error (location, code, type0, type1);
9961       return error_mark_node;
9962     }
9963
9964   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9965        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9966       &&
9967       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9968        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9969     {
9970       bool first_complex = (code0 == COMPLEX_TYPE);
9971       bool second_complex = (code1 == COMPLEX_TYPE);
9972       int none_complex = (!first_complex && !second_complex);
9973
9974       if (shorten || common || short_compare)
9975         {
9976           result_type = c_common_type (type0, type1);
9977           do_warn_double_promotion (result_type, type0, type1,
9978                                     "implicit conversion from %qT to %qT "
9979                                     "to match other operand of binary "
9980                                     "expression",
9981                                     location);
9982           if (result_type == error_mark_node)
9983             return error_mark_node;
9984         }
9985
9986       if (first_complex != second_complex
9987           && (code == PLUS_EXPR
9988               || code == MINUS_EXPR
9989               || code == MULT_EXPR
9990               || (code == TRUNC_DIV_EXPR && first_complex))
9991           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9992           && flag_signed_zeros)
9993         {
9994           /* An operation on mixed real/complex operands must be
9995              handled specially, but the language-independent code can
9996              more easily optimize the plain complex arithmetic if
9997              -fno-signed-zeros.  */
9998           tree real_type = TREE_TYPE (result_type);
9999           tree real, imag;
10000           if (type0 != orig_type0 || type1 != orig_type1)
10001             {
10002               gcc_assert (may_need_excess_precision && common);
10003               semantic_result_type = c_common_type (orig_type0, orig_type1);
10004             }
10005           if (first_complex)
10006             {
10007               if (TREE_TYPE (op0) != result_type)
10008                 op0 = convert_and_check (result_type, op0);
10009               if (TREE_TYPE (op1) != real_type)
10010                 op1 = convert_and_check (real_type, op1);
10011             }
10012           else
10013             {
10014               if (TREE_TYPE (op0) != real_type)
10015                 op0 = convert_and_check (real_type, op0);
10016               if (TREE_TYPE (op1) != result_type)
10017                 op1 = convert_and_check (result_type, op1);
10018             }
10019           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
10020             return error_mark_node;
10021           if (first_complex)
10022             {
10023               op0 = c_save_expr (op0);
10024               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
10025                                      op0, 1);
10026               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
10027                                      op0, 1);
10028               switch (code)
10029                 {
10030                 case MULT_EXPR:
10031                 case TRUNC_DIV_EXPR:
10032                   imag = build2 (resultcode, real_type, imag, op1);
10033                   /* Fall through.  */
10034                 case PLUS_EXPR:
10035                 case MINUS_EXPR:
10036                   real = build2 (resultcode, real_type, real, op1);
10037                   break;
10038                 default:
10039                   gcc_unreachable();
10040                 }
10041             }
10042           else
10043             {
10044               op1 = c_save_expr (op1);
10045               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
10046                                      op1, 1);
10047               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
10048                                      op1, 1);
10049               switch (code)
10050                 {
10051                 case MULT_EXPR:
10052                   imag = build2 (resultcode, real_type, op0, imag);
10053                   /* Fall through.  */
10054                 case PLUS_EXPR:
10055                   real = build2 (resultcode, real_type, op0, real);
10056                   break;
10057                 case MINUS_EXPR:
10058                   real = build2 (resultcode, real_type, op0, real);
10059                   imag = build1 (NEGATE_EXPR, real_type, imag);
10060                   break;
10061                 default:
10062                   gcc_unreachable();
10063                 }
10064             }
10065           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
10066           goto return_build_binary_op;
10067         }
10068
10069       /* For certain operations (which identify themselves by shorten != 0)
10070          if both args were extended from the same smaller type,
10071          do the arithmetic in that type and then extend.
10072
10073          shorten !=0 and !=1 indicates a bitwise operation.
10074          For them, this optimization is safe only if
10075          both args are zero-extended or both are sign-extended.
10076          Otherwise, we might change the result.
10077          Eg, (short)-1 | (unsigned short)-1 is (int)-1
10078          but calculated in (unsigned short) it would be (unsigned short)-1.  */
10079
10080       if (shorten && none_complex)
10081         {
10082           final_type = result_type;
10083           result_type = shorten_binary_op (result_type, op0, op1,
10084                                            shorten == -1);
10085         }
10086
10087       /* Shifts can be shortened if shifting right.  */
10088
10089       if (short_shift)
10090         {
10091           int unsigned_arg;
10092           tree arg0 = get_narrower (op0, &unsigned_arg);
10093
10094           final_type = result_type;
10095
10096           if (arg0 == op0 && final_type == TREE_TYPE (op0))
10097             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
10098
10099           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
10100               && tree_int_cst_sgn (op1) > 0
10101               /* We can shorten only if the shift count is less than the
10102                  number of bits in the smaller type size.  */
10103               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
10104               /* We cannot drop an unsigned shift after sign-extension.  */
10105               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
10106             {
10107               /* Do an unsigned shift if the operand was zero-extended.  */
10108               result_type
10109                 = c_common_signed_or_unsigned_type (unsigned_arg,
10110                                                     TREE_TYPE (arg0));
10111               /* Convert value-to-be-shifted to that type.  */
10112               if (TREE_TYPE (op0) != result_type)
10113                 op0 = convert (result_type, op0);
10114               converted = 1;
10115             }
10116         }
10117
10118       /* Comparison operations are shortened too but differently.
10119          They identify themselves by setting short_compare = 1.  */
10120
10121       if (short_compare)
10122         {
10123           /* Don't write &op0, etc., because that would prevent op0
10124              from being kept in a register.
10125              Instead, make copies of the our local variables and
10126              pass the copies by reference, then copy them back afterward.  */
10127           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
10128           enum tree_code xresultcode = resultcode;
10129           tree val
10130             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
10131
10132           if (val != 0)
10133             {
10134               ret = val;
10135               goto return_build_binary_op;
10136             }
10137
10138           op0 = xop0, op1 = xop1;
10139           converted = 1;
10140           resultcode = xresultcode;
10141
10142           if (c_inhibit_evaluation_warnings == 0)
10143             {
10144               bool op0_maybe_const = true;
10145               bool op1_maybe_const = true;
10146               tree orig_op0_folded, orig_op1_folded;
10147
10148               if (in_late_binary_op)
10149                 {
10150                   orig_op0_folded = orig_op0;
10151                   orig_op1_folded = orig_op1;
10152                 }
10153               else
10154                 {
10155                   /* Fold for the sake of possible warnings, as in
10156                      build_conditional_expr.  This requires the
10157                      "original" values to be folded, not just op0 and
10158                      op1.  */
10159                   c_inhibit_evaluation_warnings++;
10160                   op0 = c_fully_fold (op0, require_constant_value,
10161                                       &op0_maybe_const);
10162                   op1 = c_fully_fold (op1, require_constant_value,
10163                                       &op1_maybe_const);
10164                   c_inhibit_evaluation_warnings--;
10165                   orig_op0_folded = c_fully_fold (orig_op0,
10166                                                   require_constant_value,
10167                                                   NULL);
10168                   orig_op1_folded = c_fully_fold (orig_op1,
10169                                                   require_constant_value,
10170                                                   NULL);
10171                 }
10172
10173               if (warn_sign_compare)
10174                 warn_for_sign_compare (location, orig_op0_folded,
10175                                        orig_op1_folded, op0, op1,
10176                                        result_type, resultcode);
10177               if (!in_late_binary_op)
10178                 {
10179                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
10180                     op0 = c_wrap_maybe_const (op0, !op0_maybe_const);
10181                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
10182                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
10183                 }
10184             }
10185         }
10186     }
10187
10188   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
10189      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
10190      Then the expression will be built.
10191      It will be given type FINAL_TYPE if that is nonzero;
10192      otherwise, it will be given type RESULT_TYPE.  */
10193
10194   if (!result_type)
10195     {
10196       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
10197       return error_mark_node;
10198     }
10199
10200   if (build_type == NULL_TREE)
10201     {
10202       build_type = result_type;
10203       if ((type0 != orig_type0 || type1 != orig_type1)
10204           && !boolean_op)
10205         {
10206           gcc_assert (may_need_excess_precision && common);
10207           semantic_result_type = c_common_type (orig_type0, orig_type1);
10208         }
10209     }
10210
10211   if (!converted)
10212     {
10213       op0 = ep_convert_and_check (result_type, op0, semantic_result_type);
10214       op1 = ep_convert_and_check (result_type, op1, semantic_result_type);
10215
10216       /* This can happen if one operand has a vector type, and the other
10217          has a different type.  */
10218       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
10219         return error_mark_node;
10220     }
10221
10222   /* Treat expressions in initializers specially as they can't trap.  */
10223   if (int_const_or_overflow)
10224     ret = (require_constant_value
10225            ? fold_build2_initializer_loc (location, resultcode, build_type,
10226                                           op0, op1)
10227            : fold_build2_loc (location, resultcode, build_type, op0, op1));
10228   else
10229     ret = build2 (resultcode, build_type, op0, op1);
10230   if (final_type != 0)
10231     ret = convert (final_type, ret);
10232
10233  return_build_binary_op:
10234   gcc_assert (ret != error_mark_node);
10235   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
10236     ret = (int_operands
10237            ? note_integer_operands (ret)
10238            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
10239   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
10240            && !in_late_binary_op)
10241     ret = note_integer_operands (ret);
10242   if (semantic_result_type)
10243     ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
10244   protected_set_expr_location (ret, location);
10245   return ret;
10246 }
10247
10248
10249 /* Convert EXPR to be a truth-value, validating its type for this
10250    purpose.  LOCATION is the source location for the expression.  */
10251
10252 tree
10253 c_objc_common_truthvalue_conversion (location_t location, tree expr)
10254 {
10255   bool int_const, int_operands;
10256
10257   switch (TREE_CODE (TREE_TYPE (expr)))
10258     {
10259     case ARRAY_TYPE:
10260       error_at (location, "used array that cannot be converted to pointer where scalar is required");
10261       return error_mark_node;
10262
10263     case RECORD_TYPE:
10264       error_at (location, "used struct type value where scalar is required");
10265       return error_mark_node;
10266
10267     case UNION_TYPE:
10268       error_at (location, "used union type value where scalar is required");
10269       return error_mark_node;
10270
10271     case FUNCTION_TYPE:
10272       gcc_unreachable ();
10273
10274     default:
10275       break;
10276     }
10277
10278   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
10279   int_operands = EXPR_INT_CONST_OPERANDS (expr);
10280   if (int_operands)
10281     expr = remove_c_maybe_const_expr (expr);
10282
10283   /* ??? Should we also give an error for void and vectors rather than
10284      leaving those to give errors later?  */
10285   expr = c_common_truthvalue_conversion (location, expr);
10286
10287   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
10288     {
10289       if (TREE_OVERFLOW (expr))
10290         return expr;
10291       else
10292         return note_integer_operands (expr);
10293     }
10294   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
10295     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
10296   return expr;
10297 }
10298 \f
10299
10300 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
10301    required.  */
10302
10303 tree
10304 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
10305 {
10306   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
10307     {
10308       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
10309       /* Executing a compound literal inside a function reinitializes
10310          it.  */
10311       if (!TREE_STATIC (decl))
10312         *se = true;
10313       return decl;
10314     }
10315   else
10316     return expr;
10317 }
10318 \f
10319 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
10320
10321 tree
10322 c_begin_omp_parallel (void)
10323 {
10324   tree block;
10325
10326   keep_next_level ();
10327   block = c_begin_compound_stmt (true);
10328
10329   return block;
10330 }
10331
10332 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
10333    statement.  LOC is the location of the OMP_PARALLEL.  */
10334
10335 tree
10336 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
10337 {
10338   tree stmt;
10339
10340   block = c_end_compound_stmt (loc, block, true);
10341
10342   stmt = make_node (OMP_PARALLEL);
10343   TREE_TYPE (stmt) = void_type_node;
10344   OMP_PARALLEL_CLAUSES (stmt) = clauses;
10345   OMP_PARALLEL_BODY (stmt) = block;
10346   SET_EXPR_LOCATION (stmt, loc);
10347
10348   return add_stmt (stmt);
10349 }
10350
10351 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
10352
10353 tree
10354 c_begin_omp_task (void)
10355 {
10356   tree block;
10357
10358   keep_next_level ();
10359   block = c_begin_compound_stmt (true);
10360
10361   return block;
10362 }
10363
10364 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
10365    statement.  LOC is the location of the #pragma.  */
10366
10367 tree
10368 c_finish_omp_task (location_t loc, tree clauses, tree block)
10369 {
10370   tree stmt;
10371
10372   block = c_end_compound_stmt (loc, block, true);
10373
10374   stmt = make_node (OMP_TASK);
10375   TREE_TYPE (stmt) = void_type_node;
10376   OMP_TASK_CLAUSES (stmt) = clauses;
10377   OMP_TASK_BODY (stmt) = block;
10378   SET_EXPR_LOCATION (stmt, loc);
10379
10380   return add_stmt (stmt);
10381 }
10382
10383 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
10384    Remove any elements from the list that are invalid.  */
10385
10386 tree
10387 c_finish_omp_clauses (tree clauses)
10388 {
10389   bitmap_head generic_head, firstprivate_head, lastprivate_head;
10390   tree c, t, *pc = &clauses;
10391   const char *name;
10392
10393   bitmap_obstack_initialize (NULL);
10394   bitmap_initialize (&generic_head, &bitmap_default_obstack);
10395   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
10396   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
10397
10398   for (pc = &clauses, c = clauses; c ; c = *pc)
10399     {
10400       bool remove = false;
10401       bool need_complete = false;
10402       bool need_implicitly_determined = false;
10403
10404       switch (OMP_CLAUSE_CODE (c))
10405         {
10406         case OMP_CLAUSE_SHARED:
10407           name = "shared";
10408           need_implicitly_determined = true;
10409           goto check_dup_generic;
10410
10411         case OMP_CLAUSE_PRIVATE:
10412           name = "private";
10413           need_complete = true;
10414           need_implicitly_determined = true;
10415           goto check_dup_generic;
10416
10417         case OMP_CLAUSE_REDUCTION:
10418           name = "reduction";
10419           need_implicitly_determined = true;
10420           t = OMP_CLAUSE_DECL (c);
10421           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
10422               || POINTER_TYPE_P (TREE_TYPE (t)))
10423             {
10424               error_at (OMP_CLAUSE_LOCATION (c),
10425                         "%qE has invalid type for %<reduction%>", t);
10426               remove = true;
10427             }
10428           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
10429             {
10430               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
10431               const char *r_name = NULL;
10432
10433               switch (r_code)
10434                 {
10435                 case PLUS_EXPR:
10436                 case MULT_EXPR:
10437                 case MINUS_EXPR:
10438                   break;
10439                 case BIT_AND_EXPR:
10440                   r_name = "&";
10441                   break;
10442                 case BIT_XOR_EXPR:
10443                   r_name = "^";
10444                   break;
10445                 case BIT_IOR_EXPR:
10446                   r_name = "|";
10447                   break;
10448                 case TRUTH_ANDIF_EXPR:
10449                   r_name = "&&";
10450                   break;
10451                 case TRUTH_ORIF_EXPR:
10452                   r_name = "||";
10453                   break;
10454                 default:
10455                   gcc_unreachable ();
10456                 }
10457               if (r_name)
10458                 {
10459                   error_at (OMP_CLAUSE_LOCATION (c),
10460                             "%qE has invalid type for %<reduction(%s)%>",
10461                             t, r_name);
10462                   remove = true;
10463                 }
10464             }
10465           goto check_dup_generic;
10466
10467         case OMP_CLAUSE_COPYPRIVATE:
10468           name = "copyprivate";
10469           goto check_dup_generic;
10470
10471         case OMP_CLAUSE_COPYIN:
10472           name = "copyin";
10473           t = OMP_CLAUSE_DECL (c);
10474           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
10475             {
10476               error_at (OMP_CLAUSE_LOCATION (c),
10477                         "%qE must be %<threadprivate%> for %<copyin%>", t);
10478               remove = true;
10479             }
10480           goto check_dup_generic;
10481
10482         check_dup_generic:
10483           t = OMP_CLAUSE_DECL (c);
10484           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10485             {
10486               error_at (OMP_CLAUSE_LOCATION (c),
10487                         "%qE is not a variable in clause %qs", t, name);
10488               remove = true;
10489             }
10490           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10491                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
10492                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10493             {
10494               error_at (OMP_CLAUSE_LOCATION (c),
10495                         "%qE appears more than once in data clauses", t);
10496               remove = true;
10497             }
10498           else
10499             bitmap_set_bit (&generic_head, DECL_UID (t));
10500           break;
10501
10502         case OMP_CLAUSE_FIRSTPRIVATE:
10503           name = "firstprivate";
10504           t = OMP_CLAUSE_DECL (c);
10505           need_complete = true;
10506           need_implicitly_determined = true;
10507           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10508             {
10509               error_at (OMP_CLAUSE_LOCATION (c),
10510                         "%qE is not a variable in clause %<firstprivate%>", t);
10511               remove = true;
10512             }
10513           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10514                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
10515             {
10516               error_at (OMP_CLAUSE_LOCATION (c),
10517                         "%qE appears more than once in data clauses", t);
10518               remove = true;
10519             }
10520           else
10521             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
10522           break;
10523
10524         case OMP_CLAUSE_LASTPRIVATE:
10525           name = "lastprivate";
10526           t = OMP_CLAUSE_DECL (c);
10527           need_complete = true;
10528           need_implicitly_determined = true;
10529           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10530             {
10531               error_at (OMP_CLAUSE_LOCATION (c),
10532                         "%qE is not a variable in clause %<lastprivate%>", t);
10533               remove = true;
10534             }
10535           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10536                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10537             {
10538               error_at (OMP_CLAUSE_LOCATION (c),
10539                      "%qE appears more than once in data clauses", t);
10540               remove = true;
10541             }
10542           else
10543             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
10544           break;
10545
10546         case OMP_CLAUSE_IF:
10547         case OMP_CLAUSE_NUM_THREADS:
10548         case OMP_CLAUSE_SCHEDULE:
10549         case OMP_CLAUSE_NOWAIT:
10550         case OMP_CLAUSE_ORDERED:
10551         case OMP_CLAUSE_DEFAULT:
10552         case OMP_CLAUSE_UNTIED:
10553         case OMP_CLAUSE_COLLAPSE:
10554           pc = &OMP_CLAUSE_CHAIN (c);
10555           continue;
10556
10557         default:
10558           gcc_unreachable ();
10559         }
10560
10561       if (!remove)
10562         {
10563           t = OMP_CLAUSE_DECL (c);
10564
10565           if (need_complete)
10566             {
10567               t = require_complete_type (t);
10568               if (t == error_mark_node)
10569                 remove = true;
10570             }
10571
10572           if (need_implicitly_determined)
10573             {
10574               const char *share_name = NULL;
10575
10576               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
10577                 share_name = "threadprivate";
10578               else switch (c_omp_predetermined_sharing (t))
10579                 {
10580                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
10581                   break;
10582                 case OMP_CLAUSE_DEFAULT_SHARED:
10583                   share_name = "shared";
10584                   break;
10585                 case OMP_CLAUSE_DEFAULT_PRIVATE:
10586                   share_name = "private";
10587                   break;
10588                 default:
10589                   gcc_unreachable ();
10590                 }
10591               if (share_name)
10592                 {
10593                   error_at (OMP_CLAUSE_LOCATION (c),
10594                             "%qE is predetermined %qs for %qs",
10595                             t, share_name, name);
10596                   remove = true;
10597                 }
10598             }
10599         }
10600
10601       if (remove)
10602         *pc = OMP_CLAUSE_CHAIN (c);
10603       else
10604         pc = &OMP_CLAUSE_CHAIN (c);
10605     }
10606
10607   bitmap_obstack_release (NULL);
10608   return clauses;
10609 }
10610
10611 /* Make a variant type in the proper way for C/C++, propagating qualifiers
10612    down to the element type of an array.  */
10613
10614 tree
10615 c_build_qualified_type (tree type, int type_quals)
10616 {
10617   if (type == error_mark_node)
10618     return type;
10619
10620   if (TREE_CODE (type) == ARRAY_TYPE)
10621     {
10622       tree t;
10623       tree element_type = c_build_qualified_type (TREE_TYPE (type),
10624                                                   type_quals);
10625
10626       /* See if we already have an identically qualified type.  */
10627       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
10628         {
10629           if (TYPE_QUALS (strip_array_types (t)) == type_quals
10630               && TYPE_NAME (t) == TYPE_NAME (type)
10631               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
10632               && attribute_list_equal (TYPE_ATTRIBUTES (t),
10633                                        TYPE_ATTRIBUTES (type)))
10634             break;
10635         }
10636       if (!t)
10637         {
10638           tree domain = TYPE_DOMAIN (type);
10639
10640           t = build_variant_type_copy (type);
10641           TREE_TYPE (t) = element_type;
10642
10643           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
10644               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10645             SET_TYPE_STRUCTURAL_EQUALITY (t);
10646           else if (TYPE_CANONICAL (element_type) != element_type
10647                    || (domain && TYPE_CANONICAL (domain) != domain))
10648             {
10649               tree unqualified_canon
10650                 = build_array_type (TYPE_CANONICAL (element_type),
10651                                     domain? TYPE_CANONICAL (domain)
10652                                           : NULL_TREE);
10653               TYPE_CANONICAL (t)
10654                 = c_build_qualified_type (unqualified_canon, type_quals);
10655             }
10656           else
10657             TYPE_CANONICAL (t) = t;
10658         }
10659       return t;
10660     }
10661
10662   /* A restrict-qualified pointer type must be a pointer to object or
10663      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10664      REFERENCE_TYPEs, which is appropriate for C++.  */
10665   if ((type_quals & TYPE_QUAL_RESTRICT)
10666       && (!POINTER_TYPE_P (type)
10667           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10668     {
10669       error ("invalid use of %<restrict%>");
10670       type_quals &= ~TYPE_QUAL_RESTRICT;
10671     }
10672
10673   return build_qualified_type (type, type_quals);
10674 }
10675
10676 /* Build a VA_ARG_EXPR for the C parser.  */
10677
10678 tree
10679 c_build_va_arg (location_t loc, tree expr, tree type)
10680 {
10681   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10682     warning_at (loc, OPT_Wc___compat,
10683                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10684   return build_va_arg (loc, expr, type);
10685 }