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
   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 "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_assign,
  53   ic_init,
  54   ic_return
  55 };
  56
  57 /* The level of nesting inside "__alignof__".  */
  58 int in_alignof;
  59
  60 /* The level of nesting inside "sizeof".  */
  61 int in_sizeof;
  62
  63 /* The level of nesting inside "typeof".  */
  64 int in_typeof;
  65
  66 struct c_label_context_se *label_context_stack_se;
  67 struct c_label_context_vm *label_context_stack_vm;
  68
  69 /* Nonzero if we've already printed a "missing braces around initializer"
  70    message within this initializer.  */
  71 static int missing_braces_mentioned;
  72
  73 static int require_constant_value;
  74 static int require_constant_elements;
  75
  76 static bool null_pointer_constant_p (const_tree);
  77 static tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (const_tree, const_tree);
  81 static int type_lists_compatible_p (const_tree, const_tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static int spelling_length (void);
  92 static char *print_spelling (char *);
  93 static void warning_init (int, const char *);
  94 static tree digest_init (tree, tree, bool, int);
  95 static void output_init_element (tree, bool, tree, tree, int, bool);
  96 static void output_pending_init_elements (int);
  97 static int set_designator (int);
  98 static void push_range_stack (tree);
  99 static void add_pending_init (tree, tree, bool);
 100 static void set_nonincremental_init (void);
 101 static void set_nonincremental_init_from_string (tree);
 102 static tree find_init_member (tree);
 103 static void readonly_error (tree, enum lvalue_use);
 104 static int lvalue_or_else (const_tree, enum lvalue_use);
 105 static int lvalue_p (const_tree);
 106 static void record_maybe_used_decl (tree);
 107 static int comptypes_internal (const_tree, const_tree);
 108 \f
 109 /* Return true if EXP is a null pointer constant, false otherwise.  */
 110
 111 static bool
 112 null_pointer_constant_p (const_tree expr)
 113 {
 114   /* This should really operate on c_expr structures, but they aren't
 115      yet available everywhere required.  */
 116   tree type = TREE_TYPE (expr);
 117   return (TREE_CODE (expr) == INTEGER_CST
 118           && !TREE_OVERFLOW (expr)
 119           && integer_zerop (expr)
 120           && (INTEGRAL_TYPE_P (type)
 121               || (TREE_CODE (type) == POINTER_TYPE
 122                   && VOID_TYPE_P (TREE_TYPE (type))
 123                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 124 }
 125 \f/* This is a cache to hold if two types are compatible or not.  */
 126
 127 struct tagged_tu_seen_cache {
 128   const struct tagged_tu_seen_cache * next;
 129   const_tree t1;
 130   const_tree t2;
 131   /* The return value of tagged_types_tu_compatible_p if we had seen
 132      these two types already.  */
 133   int val;
 134 };
 135
 136 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 137 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 138
 139 /* Do `exp = require_complete_type (exp);' to make sure exp
 140    does not have an incomplete type.  (That includes void types.)  */
 141
 142 tree
 143 require_complete_type (tree value)
 144 {
 145   tree type = TREE_TYPE (value);
 146
 147   if (value == error_mark_node || type == error_mark_node)
 148     return error_mark_node;
 149
 150   /* First, detect a valid value with a complete type.  */
 151   if (COMPLETE_TYPE_P (type))
 152     return value;
 153
 154   c_incomplete_type_error (value, type);
 155   return error_mark_node;
 156 }
 157
 158 /* Print an error message for invalid use of an incomplete type.
 159    VALUE is the expression that was used (or 0 if that isn't known)
 160    and TYPE is the type that was invalid.  */
 161
 162 void
 163 c_incomplete_type_error (const_tree value, const_tree type)
 164 {
 165   const char *type_code_string;
 166
 167   /* Avoid duplicate error message.  */
 168   if (TREE_CODE (type) == ERROR_MARK)
 169     return;
 170
 171   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 172                      || TREE_CODE (value) == PARM_DECL))
 173     error ("%qD has an incomplete type", value);
 174   else
 175     {
 176     retry:
 177       /* We must print an error message.  Be clever about what it says.  */
 178
 179       switch (TREE_CODE (type))
 180         {
 181         case RECORD_TYPE:
 182           type_code_string = "struct";
 183           break;
 184
 185         case UNION_TYPE:
 186           type_code_string = "union";
 187           break;
 188
 189         case ENUMERAL_TYPE:
 190           type_code_string = "enum";
 191           break;
 192
 193         case VOID_TYPE:
 194           error ("invalid use of void expression");
 195           return;
 196
 197         case ARRAY_TYPE:
 198           if (TYPE_DOMAIN (type))
 199             {
 200               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 201                 {
 202                   error ("invalid use of flexible array member");
 203                   return;
 204                 }
 205               type = TREE_TYPE (type);
 206               goto retry;
 207             }
 208           error ("invalid use of array with unspecified bounds");
 209           return;
 210
 211         default:
 212           gcc_unreachable ();
 213         }
 214
 215       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 216         error ("invalid use of undefined type %<%s %E%>",
 217                type_code_string, TYPE_NAME (type));
 218       else
 219         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 220         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 221     }
 222 }
 223
 224 /* Given a type, apply default promotions wrt unnamed function
 225    arguments and return the new type.  */
 226
 227 tree
 228 c_type_promotes_to (tree type)
 229 {
 230   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 231     return double_type_node;
 232
 233   if (c_promoting_integer_type_p (type))
 234     {
 235       /* Preserve unsignedness if not really getting any wider.  */
 236       if (TYPE_UNSIGNED (type)
 237           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 238         return unsigned_type_node;
 239       return integer_type_node;
 240     }
 241
 242   return type;
 243 }
 244
 245 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 246    as well as those of TYPE.  */
 247
 248 static tree
 249 qualify_type (tree type, tree like)
 250 {
 251   return c_build_qualified_type (type,
 252                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 253 }
 254
 255 /* Return true iff the given tree T is a variable length array.  */
 256
 257 bool
 258 c_vla_type_p (const_tree t)
 259 {
 260   if (TREE_CODE (t) == ARRAY_TYPE
 261       && C_TYPE_VARIABLE_SIZE (t))
 262     return true;
 263   return false;
 264 }
 265 \f
 266 /* Return the composite type of two compatible types.
 267
 268    We assume that comptypes has already been done and returned
 269    nonzero; if that isn't so, this may crash.  In particular, we
 270    assume that qualifiers match.  */
 271
 272 tree
 273 composite_type (tree t1, tree t2)
 274 {
 275   enum tree_code code1;
 276   enum tree_code code2;
 277   tree attributes;
 278
 279   /* Save time if the two types are the same.  */
 280
 281   if (t1 == t2) return t1;
 282
 283   /* If one type is nonsense, use the other.  */
 284   if (t1 == error_mark_node)
 285     return t2;
 286   if (t2 == error_mark_node)
 287     return t1;
 288
 289   code1 = TREE_CODE (t1);
 290   code2 = TREE_CODE (t2);
 291
 292   /* Merge the attributes.  */
 293   attributes = targetm.merge_type_attributes (t1, t2);
 294
 295   /* If one is an enumerated type and the other is the compatible
 296      integer type, the composite type might be either of the two
 297      (DR#013 question 3).  For consistency, use the enumerated type as
 298      the composite type.  */
 299
 300   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 301     return t1;
 302   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 303     return t2;
 304
 305   gcc_assert (code1 == code2);
 306
 307   switch (code1)
 308     {
 309     case POINTER_TYPE:
 310       /* For two pointers, do this recursively on the target type.  */
 311       {
 312         tree pointed_to_1 = TREE_TYPE (t1);
 313         tree pointed_to_2 = TREE_TYPE (t2);
 314         tree target = composite_type (pointed_to_1, pointed_to_2);
 315         t1 = build_pointer_type (target);
 316         t1 = build_type_attribute_variant (t1, attributes);
 317         return qualify_type (t1, t2);
 318       }
 319
 320     case ARRAY_TYPE:
 321       {
 322         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 323         int quals;
 324         tree unqual_elt;
 325         tree d1 = TYPE_DOMAIN (t1);
 326         tree d2 = TYPE_DOMAIN (t2);
 327         bool d1_variable, d2_variable;
 328         bool d1_zero, d2_zero;
 329
 330         /* We should not have any type quals on arrays at all.  */
 331         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 332
 333         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 334         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 335
 336         d1_variable = (!d1_zero
 337                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 338                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 339         d2_variable = (!d2_zero
 340                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 341                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 342         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 343         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 344
 345         /* Save space: see if the result is identical to one of the args.  */
 346         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 347             && (d2_variable || d2_zero || !d1_variable))
 348           return build_type_attribute_variant (t1, attributes);
 349         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 350             && (d1_variable || d1_zero || !d2_variable))
 351           return build_type_attribute_variant (t2, attributes);
 352
 353         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 354           return build_type_attribute_variant (t1, attributes);
 355         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 356           return build_type_attribute_variant (t2, attributes);
 357
 358         /* Merge the element types, and have a size if either arg has
 359            one.  We may have qualifiers on the element types.  To set
 360            up TYPE_MAIN_VARIANT correctly, we need to form the
 361            composite of the unqualified types and add the qualifiers
 362            back at the end.  */
 363         quals = TYPE_QUALS (strip_array_types (elt));
 364         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 365         t1 = build_array_type (unqual_elt,
 366                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 367                                              && (d2_variable
 368                                                  || d2_zero
 369                                                  || !d1_variable))
 370                                             ? t1
 371                                             : t2));
 372         t1 = c_build_qualified_type (t1, quals);
 373         return build_type_attribute_variant (t1, attributes);
 374       }
 375
 376     case ENUMERAL_TYPE:
 377     case RECORD_TYPE:
 378     case UNION_TYPE:
 379       if (attributes != NULL)
 380         {
 381           /* Try harder not to create a new aggregate type.  */
 382           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 383             return t1;
 384           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 385             return t2;
 386         }
 387       return build_type_attribute_variant (t1, attributes);
 388
 389     case FUNCTION_TYPE:
 390       /* Function types: prefer the one that specified arg types.
 391          If both do, merge the arg types.  Also merge the return types.  */
 392       {
 393         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 394         tree p1 = TYPE_ARG_TYPES (t1);
 395         tree p2 = TYPE_ARG_TYPES (t2);
 396         int len;
 397         tree newargs, n;
 398         int i;
 399
 400         /* Save space: see if the result is identical to one of the args.  */
 401         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 402           return build_type_attribute_variant (t1, attributes);
 403         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 404           return build_type_attribute_variant (t2, attributes);
 405
 406         /* Simple way if one arg fails to specify argument types.  */
 407         if (TYPE_ARG_TYPES (t1) == 0)
 408          {
 409             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 410             t1 = build_type_attribute_variant (t1, attributes);
 411             return qualify_type (t1, t2);
 412          }
 413         if (TYPE_ARG_TYPES (t2) == 0)
 414          {
 415            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 416            t1 = build_type_attribute_variant (t1, attributes);
 417            return qualify_type (t1, t2);
 418          }
 419
 420         /* If both args specify argument types, we must merge the two
 421            lists, argument by argument.  */
 422         /* Tell global_bindings_p to return false so that variable_size
 423            doesn't die on VLAs in parameter types.  */
 424         c_override_global_bindings_to_false = true;
 425
 426         len = list_length (p1);
 427         newargs = 0;
 428
 429         for (i = 0; i < len; i++)
 430           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 431
 432         n = newargs;
 433
 434         for (; p1;
 435              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 436           {
 437             /* A null type means arg type is not specified.
 438                Take whatever the other function type has.  */
 439             if (TREE_VALUE (p1) == 0)
 440               {
 441                 TREE_VALUE (n) = TREE_VALUE (p2);
 442                 goto parm_done;
 443               }
 444             if (TREE_VALUE (p2) == 0)
 445               {
 446                 TREE_VALUE (n) = TREE_VALUE (p1);
 447                 goto parm_done;
 448               }
 449
 450             /* Given  wait (union {union wait *u; int *i} *)
 451                and  wait (union wait *),
 452                prefer  union wait *  as type of parm.  */
 453             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 454                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 455               {
 456                 tree memb;
 457                 tree mv2 = TREE_VALUE (p2);
 458                 if (mv2 && mv2 != error_mark_node
 459                     && TREE_CODE (mv2) != ARRAY_TYPE)
 460                   mv2 = TYPE_MAIN_VARIANT (mv2);
 461                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 462                      memb; memb = TREE_CHAIN (memb))
 463                   {
 464                     tree mv3 = TREE_TYPE (memb);
 465                     if (mv3 && mv3 != error_mark_node
 466                         && TREE_CODE (mv3) != ARRAY_TYPE)
 467                       mv3 = TYPE_MAIN_VARIANT (mv3);
 468                     if (comptypes (mv3, mv2))
 469                       {
 470                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 471                                                          TREE_VALUE (p2));
 472                         pedwarn (input_location, OPT_pedantic,
 473                                  "function types not truly compatible in ISO C");
 474                         goto parm_done;
 475                       }
 476                   }
 477               }
 478             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 479                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 480               {
 481                 tree memb;
 482                 tree mv1 = TREE_VALUE (p1);
 483                 if (mv1 && mv1 != error_mark_node
 484                     && TREE_CODE (mv1) != ARRAY_TYPE)
 485                   mv1 = TYPE_MAIN_VARIANT (mv1);
 486                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 487                      memb; memb = TREE_CHAIN (memb))
 488                   {
 489                     tree mv3 = TREE_TYPE (memb);
 490                     if (mv3 && mv3 != error_mark_node
 491                         && TREE_CODE (mv3) != ARRAY_TYPE)
 492                       mv3 = TYPE_MAIN_VARIANT (mv3);
 493                     if (comptypes (mv3, mv1))
 494                       {
 495                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 496                                                          TREE_VALUE (p1));
 497                         pedwarn (input_location, OPT_pedantic,
 498                                  "function types not truly compatible in ISO C");
 499                         goto parm_done;
 500                       }
 501                   }
 502               }
 503             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 504           parm_done: ;
 505           }
 506
 507         c_override_global_bindings_to_false = false;
 508         t1 = build_function_type (valtype, newargs);
 509         t1 = qualify_type (t1, t2);
 510         /* ... falls through ...  */
 511       }
 512
 513     default:
 514       return build_type_attribute_variant (t1, attributes);
 515     }
 516
 517 }
 518
 519 /* Return the type of a conditional expression between pointers to
 520    possibly differently qualified versions of compatible types.
 521
 522    We assume that comp_target_types has already been done and returned
 523    nonzero; if that isn't so, this may crash.  */
 524
 525 static tree
 526 common_pointer_type (tree t1, tree t2)
 527 {
 528   tree attributes;
 529   tree pointed_to_1, mv1;
 530   tree pointed_to_2, mv2;
 531   tree target;
 532   unsigned target_quals;
 533
 534   /* Save time if the two types are the same.  */
 535
 536   if (t1 == t2) return t1;
 537
 538   /* If one type is nonsense, use the other.  */
 539   if (t1 == error_mark_node)
 540     return t2;
 541   if (t2 == error_mark_node)
 542     return t1;
 543
 544   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 545               && TREE_CODE (t2) == POINTER_TYPE);
 546
 547   /* Merge the attributes.  */
 548   attributes = targetm.merge_type_attributes (t1, t2);
 549
 550   /* Find the composite type of the target types, and combine the
 551      qualifiers of the two types' targets.  Do not lose qualifiers on
 552      array element types by taking the TYPE_MAIN_VARIANT.  */
 553   mv1 = pointed_to_1 = TREE_TYPE (t1);
 554   mv2 = pointed_to_2 = TREE_TYPE (t2);
 555   if (TREE_CODE (mv1) != ARRAY_TYPE)
 556     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 557   if (TREE_CODE (mv2) != ARRAY_TYPE)
 558     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 559   target = composite_type (mv1, mv2);
 560
 561   /* For function types do not merge const qualifiers, but drop them
 562      if used inconsistently.  The middle-end uses these to mark const
 563      and noreturn functions.  */
 564   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 565     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 566   else
 567     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 568   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 569   return build_type_attribute_variant (t1, attributes);
 570 }
 571
 572 /* Return the common type for two arithmetic types under the usual
 573    arithmetic conversions.  The default conversions have already been
 574    applied, and enumerated types converted to their compatible integer
 575    types.  The resulting type is unqualified and has no attributes.
 576
 577    This is the type for the result of most arithmetic operations
 578    if the operands have the given two types.  */
 579
 580 static tree
 581 c_common_type (tree t1, tree t2)
 582 {
 583   enum tree_code code1;
 584   enum tree_code code2;
 585
 586   /* If one type is nonsense, use the other.  */
 587   if (t1 == error_mark_node)
 588     return t2;
 589   if (t2 == error_mark_node)
 590     return t1;
 591
 592   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 593     t1 = TYPE_MAIN_VARIANT (t1);
 594
 595   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 596     t2 = TYPE_MAIN_VARIANT (t2);
 597
 598   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 599     t1 = build_type_attribute_variant (t1, NULL_TREE);
 600
 601   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 602     t2 = build_type_attribute_variant (t2, NULL_TREE);
 603
 604   /* Save time if the two types are the same.  */
 605
 606   if (t1 == t2) return t1;
 607
 608   code1 = TREE_CODE (t1);
 609   code2 = TREE_CODE (t2);
 610
 611   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 612               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 613               || code1 == INTEGER_TYPE);
 614   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 615               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 616               || code2 == INTEGER_TYPE);
 617
 618   /* When one operand is a decimal float type, the other operand cannot be
 619      a generic float type or a complex type.  We also disallow vector types
 620      here.  */
 621   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 622       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 623     {
 624       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 625         {
 626           error ("can%'t mix operands of decimal float and vector types");
 627           return error_mark_node;
 628         }
 629       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 630         {
 631           error ("can%'t mix operands of decimal float and complex types");
 632           return error_mark_node;
 633         }
 634       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 635         {
 636           error ("can%'t mix operands of decimal float and other float types");
 637           return error_mark_node;
 638         }
 639     }
 640
 641   /* If one type is a vector type, return that type.  (How the usual
 642      arithmetic conversions apply to the vector types extension is not
 643      precisely specified.)  */
 644   if (code1 == VECTOR_TYPE)
 645     return t1;
 646
 647   if (code2 == VECTOR_TYPE)
 648     return t2;
 649
 650   /* If one type is complex, form the common type of the non-complex
 651      components, then make that complex.  Use T1 or T2 if it is the
 652      required type.  */
 653   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 654     {
 655       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 656       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 657       tree subtype = c_common_type (subtype1, subtype2);
 658
 659       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 660         return t1;
 661       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 662         return t2;
 663       else
 664         return build_complex_type (subtype);
 665     }
 666
 667   /* If only one is real, use it as the result.  */
 668
 669   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 670     return t1;
 671
 672   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 673     return t2;
 674
 675   /* If both are real and either are decimal floating point types, use
 676      the decimal floating point type with the greater precision. */
 677
 678   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 679     {
 680       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 681           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 682         return dfloat128_type_node;
 683       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 684                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 685         return dfloat64_type_node;
 686       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 687                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 688         return dfloat32_type_node;
 689     }
 690
 691   /* Deal with fixed-point types.  */
 692   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 693     {
 694       unsigned int unsignedp = 0, satp = 0;
 695       enum machine_mode m1, m2;
 696       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 697
 698       m1 = TYPE_MODE (t1);
 699       m2 = TYPE_MODE (t2);
 700
 701       /* If one input type is saturating, the result type is saturating.  */
 702       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 703         satp = 1;
 704
 705       /* If both fixed-point types are unsigned, the result type is unsigned.
 706          When mixing fixed-point and integer types, follow the sign of the
 707          fixed-point type.
 708          Otherwise, the result type is signed.  */
 709       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 710            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 711           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 712               && TYPE_UNSIGNED (t1))
 713           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 714               && TYPE_UNSIGNED (t2)))
 715         unsignedp = 1;
 716
 717       /* The result type is signed.  */
 718       if (unsignedp == 0)
 719         {
 720           /* If the input type is unsigned, we need to convert to the
 721              signed type.  */
 722           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 723             {
 724               enum mode_class mclass = (enum mode_class) 0;
 725               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 726                 mclass = MODE_FRACT;
 727               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 728                 mclass = MODE_ACCUM;
 729               else
 730                 gcc_unreachable ();
 731               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 732             }
 733           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 734             {
 735               enum mode_class mclass = (enum mode_class) 0;
 736               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 737                 mclass = MODE_FRACT;
 738               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 739                 mclass = MODE_ACCUM;
 740               else
 741                 gcc_unreachable ();
 742               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 743             }
 744         }
 745
 746       if (code1 == FIXED_POINT_TYPE)
 747         {
 748           fbit1 = GET_MODE_FBIT (m1);
 749           ibit1 = GET_MODE_IBIT (m1);
 750         }
 751       else
 752         {
 753           fbit1 = 0;
 754           /* Signed integers need to subtract one sign bit.  */
 755           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 756         }
 757
 758       if (code2 == FIXED_POINT_TYPE)
 759         {
 760           fbit2 = GET_MODE_FBIT (m2);
 761           ibit2 = GET_MODE_IBIT (m2);
 762         }
 763       else
 764         {
 765           fbit2 = 0;
 766           /* Signed integers need to subtract one sign bit.  */
 767           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 768         }
 769
 770       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 771       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 772       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 773                                                  satp);
 774     }
 775
 776   /* Both real or both integers; use the one with greater precision.  */
 777
 778   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 779     return t1;
 780   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 781     return t2;
 782
 783   /* Same precision.  Prefer long longs to longs to ints when the
 784      same precision, following the C99 rules on integer type rank
 785      (which are equivalent to the C90 rules for C90 types).  */
 786
 787   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 788       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 789     return long_long_unsigned_type_node;
 790
 791   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 792       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 793     {
 794       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 795         return long_long_unsigned_type_node;
 796       else
 797         return long_long_integer_type_node;
 798     }
 799
 800   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 801       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 802     return long_unsigned_type_node;
 803
 804   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 805       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 806     {
 807       /* But preserve unsignedness from the other type,
 808          since long cannot hold all the values of an unsigned int.  */
 809       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 810         return long_unsigned_type_node;
 811       else
 812         return long_integer_type_node;
 813     }
 814
 815   /* Likewise, prefer long double to double even if same size.  */
 816   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 817       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 818     return long_double_type_node;
 819
 820   /* Otherwise prefer the unsigned one.  */
 821
 822   if (TYPE_UNSIGNED (t1))
 823     return t1;
 824   else
 825     return t2;
 826 }
 827 \f
 828 /* Wrapper around c_common_type that is used by c-common.c and other
 829    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 830    are allowed here and are converted to their compatible integer types.
 831    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 832    preferably a non-Boolean type as the common type.  */
 833 tree
 834 common_type (tree t1, tree t2)
 835 {
 836   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 837     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 838   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 839     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 840
 841   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 842   if (TREE_CODE (t1) == BOOLEAN_TYPE
 843       && TREE_CODE (t2) == BOOLEAN_TYPE)
 844     return boolean_type_node;
 845
 846   /* If either type is BOOLEAN_TYPE, then return the other.  */
 847   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 848     return t2;
 849   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 850     return t1;
 851
 852   return c_common_type (t1, t2);
 853 }
 854
 855 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 856    or various other operations.  Return 2 if they are compatible
 857    but a warning may be needed if you use them together.  */
 858
 859 int
 860 comptypes (tree type1, tree type2)
 861 {
 862   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 863   int val;
 864
 865   val = comptypes_internal (type1, type2);
 866   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 867
 868   return val;
 869 }
 870 \f
 871 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 872    or various other operations.  Return 2 if they are compatible
 873    but a warning may be needed if you use them together.  This
 874    differs from comptypes, in that we don't free the seen types.  */
 875
 876 static int
 877 comptypes_internal (const_tree type1, const_tree type2)
 878 {
 879   const_tree t1 = type1;
 880   const_tree t2 = type2;
 881   int attrval, val;
 882
 883   /* Suppress errors caused by previously reported errors.  */
 884
 885   if (t1 == t2 || !t1 || !t2
 886       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 887     return 1;
 888
 889   /* If either type is the internal version of sizetype, return the
 890      language version.  */
 891   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 892       && TYPE_ORIG_SIZE_TYPE (t1))
 893     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 894
 895   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 896       && TYPE_ORIG_SIZE_TYPE (t2))
 897     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 898
 899
 900   /* Enumerated types are compatible with integer types, but this is
 901      not transitive: two enumerated types in the same translation unit
 902      are compatible with each other only if they are the same type.  */
 903
 904   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 905     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 906   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 907     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 908
 909   if (t1 == t2)
 910     return 1;
 911
 912   /* Different classes of types can't be compatible.  */
 913
 914   if (TREE_CODE (t1) != TREE_CODE (t2))
 915     return 0;
 916
 917   /* Qualifiers must match. C99 6.7.3p9 */
 918
 919   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 920     return 0;
 921
 922   /* Allow for two different type nodes which have essentially the same
 923      definition.  Note that we already checked for equality of the type
 924      qualifiers (just above).  */
 925
 926   if (TREE_CODE (t1) != ARRAY_TYPE
 927       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 928     return 1;
 929
 930   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 931   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 932      return 0;
 933
 934   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 935   val = 0;
 936
 937   switch (TREE_CODE (t1))
 938     {
 939     case POINTER_TYPE:
 940       /* Do not remove mode or aliasing information.  */
 941       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 942           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 943         break;
 944       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 945              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 946       break;
 947
 948     case FUNCTION_TYPE:
 949       val = function_types_compatible_p (t1, t2);
 950       break;
 951
 952     case ARRAY_TYPE:
 953       {
 954         tree d1 = TYPE_DOMAIN (t1);
 955         tree d2 = TYPE_DOMAIN (t2);
 956         bool d1_variable, d2_variable;
 957         bool d1_zero, d2_zero;
 958         val = 1;
 959
 960         /* Target types must match incl. qualifiers.  */
 961         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 962             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 963           return 0;
 964
 965         /* Sizes must match unless one is missing or variable.  */
 966         if (d1 == 0 || d2 == 0 || d1 == d2)
 967           break;
 968
 969         d1_zero = !TYPE_MAX_VALUE (d1);
 970         d2_zero = !TYPE_MAX_VALUE (d2);
 971
 972         d1_variable = (!d1_zero
 973                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 974                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 975         d2_variable = (!d2_zero
 976                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 977                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 978         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 979         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 980
 981         if (d1_variable || d2_variable)
 982           break;
 983         if (d1_zero && d2_zero)
 984           break;
 985         if (d1_zero || d2_zero
 986             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 987             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 988           val = 0;
 989
 990         break;
 991       }
 992
 993     case ENUMERAL_TYPE:
 994     case RECORD_TYPE:
 995     case UNION_TYPE:
 996       if (val != 1 && !same_translation_unit_p (t1, t2))
 997         {
 998           tree a1 = TYPE_ATTRIBUTES (t1);
 999           tree a2 = TYPE_ATTRIBUTES (t2);
1000
1001           if (! attribute_list_contained (a1, a2)
1002               && ! attribute_list_contained (a2, a1))
1003             break;
1004
1005           if (attrval != 2)
1006             return tagged_types_tu_compatible_p (t1, t2);
1007           val = tagged_types_tu_compatible_p (t1, t2);
1008         }
1009       break;
1010
1011     case VECTOR_TYPE:
1012       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1013             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1014       break;
1015
1016     default:
1017       break;
1018     }
1019   return attrval == 2 && val == 1 ? 2 : val;
1020 }
1021
1022 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1023    ignoring their qualifiers.  */
1024
1025 static int
1026 comp_target_types (tree ttl, tree ttr)
1027 {
1028   int val;
1029   tree mvl, mvr;
1030
1031   /* Do not lose qualifiers on element types of array types that are
1032      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1033   mvl = TREE_TYPE (ttl);
1034   mvr = TREE_TYPE (ttr);
1035   if (TREE_CODE (mvl) != ARRAY_TYPE)
1036     mvl = TYPE_MAIN_VARIANT (mvl);
1037   if (TREE_CODE (mvr) != ARRAY_TYPE)
1038     mvr = TYPE_MAIN_VARIANT (mvr);
1039   val = comptypes (mvl, mvr);
1040
1041   if (val == 2)
1042     pedwarn (input_location, OPT_pedantic, "types are not quite compatible");
1043   return val;
1044 }
1045 \f
1046 /* Subroutines of `comptypes'.  */
1047
1048 /* Determine whether two trees derive from the same translation unit.
1049    If the CONTEXT chain ends in a null, that tree's context is still
1050    being parsed, so if two trees have context chains ending in null,
1051    they're in the same translation unit.  */
1052 int
1053 same_translation_unit_p (const_tree t1, const_tree t2)
1054 {
1055   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1056     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1057       {
1058       case tcc_declaration:
1059         t1 = DECL_CONTEXT (t1); break;
1060       case tcc_type:
1061         t1 = TYPE_CONTEXT (t1); break;
1062       case tcc_exceptional:
1063         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1064       default: gcc_unreachable ();
1065       }
1066
1067   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1068     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1069       {
1070       case tcc_declaration:
1071         t2 = DECL_CONTEXT (t2); break;
1072       case tcc_type:
1073         t2 = TYPE_CONTEXT (t2); break;
1074       case tcc_exceptional:
1075         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1076       default: gcc_unreachable ();
1077       }
1078
1079   return t1 == t2;
1080 }
1081
1082 /* Allocate the seen two types, assuming that they are compatible. */
1083
1084 static struct tagged_tu_seen_cache *
1085 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1086 {
1087   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1088   tu->next = tagged_tu_seen_base;
1089   tu->t1 = t1;
1090   tu->t2 = t2;
1091
1092   tagged_tu_seen_base = tu;
1093
1094   /* The C standard says that two structures in different translation
1095      units are compatible with each other only if the types of their
1096      fields are compatible (among other things).  We assume that they
1097      are compatible until proven otherwise when building the cache.
1098      An example where this can occur is:
1099      struct a
1100      {
1101        struct a *next;
1102      };
1103      If we are comparing this against a similar struct in another TU,
1104      and did not assume they were compatible, we end up with an infinite
1105      loop.  */
1106   tu->val = 1;
1107   return tu;
1108 }
1109
1110 /* Free the seen types until we get to TU_TIL. */
1111
1112 static void
1113 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1114 {
1115   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1116   while (tu != tu_til)
1117     {
1118       const struct tagged_tu_seen_cache *const tu1
1119         = (const struct tagged_tu_seen_cache *) tu;
1120       tu = tu1->next;
1121       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1122     }
1123   tagged_tu_seen_base = tu_til;
1124 }
1125
1126 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1127    compatible.  If the two types are not the same (which has been
1128    checked earlier), this can only happen when multiple translation
1129    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1130    rules.  */
1131
1132 static int
1133 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1134 {
1135   tree s1, s2;
1136   bool needs_warning = false;
1137
1138   /* We have to verify that the tags of the types are the same.  This
1139      is harder than it looks because this may be a typedef, so we have
1140      to go look at the original type.  It may even be a typedef of a
1141      typedef...
1142      In the case of compiler-created builtin structs the TYPE_DECL
1143      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1144   while (TYPE_NAME (t1)
1145          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1146          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1147     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1148
1149   while (TYPE_NAME (t2)
1150          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1151          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1152     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1153
1154   /* C90 didn't have the requirement that the two tags be the same.  */
1155   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1156     return 0;
1157
1158   /* C90 didn't say what happened if one or both of the types were
1159      incomplete; we choose to follow C99 rules here, which is that they
1160      are compatible.  */
1161   if (TYPE_SIZE (t1) == NULL
1162       || TYPE_SIZE (t2) == NULL)
1163     return 1;
1164
1165   {
1166     const struct tagged_tu_seen_cache * tts_i;
1167     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1168       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1169         return tts_i->val;
1170   }
1171
1172   switch (TREE_CODE (t1))
1173     {
1174     case ENUMERAL_TYPE:
1175       {
1176         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1177         /* Speed up the case where the type values are in the same order.  */
1178         tree tv1 = TYPE_VALUES (t1);
1179         tree tv2 = TYPE_VALUES (t2);
1180
1181         if (tv1 == tv2)
1182           {
1183             return 1;
1184           }
1185
1186         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1187           {
1188             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1189               break;
1190             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1191               {
1192                 tu->val = 0;
1193                 return 0;
1194               }
1195           }
1196
1197         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1198           {
1199             return 1;
1200           }
1201         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1202           {
1203             tu->val = 0;
1204             return 0;
1205           }
1206
1207         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1208           {
1209             tu->val = 0;
1210             return 0;
1211           }
1212
1213         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1214           {
1215             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1216             if (s2 == NULL
1217                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1218               {
1219                 tu->val = 0;
1220                 return 0;
1221               }
1222           }
1223         return 1;
1224       }
1225
1226     case UNION_TYPE:
1227       {
1228         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1229         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1230           {
1231             tu->val = 0;
1232             return 0;
1233           }
1234
1235         /*  Speed up the common case where the fields are in the same order. */
1236         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1237              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1238           {
1239             int result;
1240
1241             if (DECL_NAME (s1) != DECL_NAME (s2))
1242               break;
1243             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1244
1245             if (result != 1 && !DECL_NAME (s1))
1246               break;
1247             if (result == 0)
1248               {
1249                 tu->val = 0;
1250                 return 0;
1251               }
1252             if (result == 2)
1253               needs_warning = true;
1254
1255             if (TREE_CODE (s1) == FIELD_DECL
1256                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1257                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1258               {
1259                 tu->val = 0;
1260                 return 0;
1261               }
1262           }
1263         if (!s1 && !s2)
1264           {
1265             tu->val = needs_warning ? 2 : 1;
1266             return tu->val;
1267           }
1268
1269         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1270           {
1271             bool ok = false;
1272
1273             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1274               if (DECL_NAME (s1) == DECL_NAME (s2))
1275                 {
1276                   int result;
1277
1278                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1279
1280                   if (result != 1 && !DECL_NAME (s1))
1281                     continue;
1282                   if (result == 0)
1283                     {
1284                       tu->val = 0;
1285                       return 0;
1286                     }
1287                   if (result == 2)
1288                     needs_warning = true;
1289
1290                   if (TREE_CODE (s1) == FIELD_DECL
1291                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1292                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1293                     break;
1294
1295                   ok = true;
1296                   break;
1297                 }
1298             if (!ok)
1299               {
1300                 tu->val = 0;
1301                 return 0;
1302               }
1303           }
1304         tu->val = needs_warning ? 2 : 10;
1305         return tu->val;
1306       }
1307
1308     case RECORD_TYPE:
1309       {
1310         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1311
1312         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1313              s1 && s2;
1314              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1315           {
1316             int result;
1317             if (TREE_CODE (s1) != TREE_CODE (s2)
1318                 || DECL_NAME (s1) != DECL_NAME (s2))
1319               break;
1320             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1321             if (result == 0)
1322               break;
1323             if (result == 2)
1324               needs_warning = true;
1325
1326             if (TREE_CODE (s1) == FIELD_DECL
1327                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1328                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1329               break;
1330           }
1331         if (s1 && s2)
1332           tu->val = 0;
1333         else
1334           tu->val = needs_warning ? 2 : 1;
1335         return tu->val;
1336       }
1337
1338     default:
1339       gcc_unreachable ();
1340     }
1341 }
1342
1343 /* Return 1 if two function types F1 and F2 are compatible.
1344    If either type specifies no argument types,
1345    the other must specify a fixed number of self-promoting arg types.
1346    Otherwise, if one type specifies only the number of arguments,
1347    the other must specify that number of self-promoting arg types.
1348    Otherwise, the argument types must match.  */
1349
1350 static int
1351 function_types_compatible_p (const_tree f1, const_tree f2)
1352 {
1353   tree args1, args2;
1354   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1355   int val = 1;
1356   int val1;
1357   tree ret1, ret2;
1358
1359   ret1 = TREE_TYPE (f1);
1360   ret2 = TREE_TYPE (f2);
1361
1362   /* 'volatile' qualifiers on a function's return type used to mean
1363      the function is noreturn.  */
1364   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1365     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1366   if (TYPE_VOLATILE (ret1))
1367     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1368                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1369   if (TYPE_VOLATILE (ret2))
1370     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1371                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1372   val = comptypes_internal (ret1, ret2);
1373   if (val == 0)
1374     return 0;
1375
1376   args1 = TYPE_ARG_TYPES (f1);
1377   args2 = TYPE_ARG_TYPES (f2);
1378
1379   /* An unspecified parmlist matches any specified parmlist
1380      whose argument types don't need default promotions.  */
1381
1382   if (args1 == 0)
1383     {
1384       if (!self_promoting_args_p (args2))
1385         return 0;
1386       /* If one of these types comes from a non-prototype fn definition,
1387          compare that with the other type's arglist.
1388          If they don't match, ask for a warning (but no error).  */
1389       if (TYPE_ACTUAL_ARG_TYPES (f1)
1390           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1391         val = 2;
1392       return val;
1393     }
1394   if (args2 == 0)
1395     {
1396       if (!self_promoting_args_p (args1))
1397         return 0;
1398       if (TYPE_ACTUAL_ARG_TYPES (f2)
1399           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1400         val = 2;
1401       return val;
1402     }
1403
1404   /* Both types have argument lists: compare them and propagate results.  */
1405   val1 = type_lists_compatible_p (args1, args2);
1406   return val1 != 1 ? val1 : val;
1407 }
1408
1409 /* Check two lists of types for compatibility,
1410    returning 0 for incompatible, 1 for compatible,
1411    or 2 for compatible with warning.  */
1412
1413 static int
1414 type_lists_compatible_p (const_tree args1, const_tree args2)
1415 {
1416   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1417   int val = 1;
1418   int newval = 0;
1419
1420   while (1)
1421     {
1422       tree a1, mv1, a2, mv2;
1423       if (args1 == 0 && args2 == 0)
1424         return val;
1425       /* If one list is shorter than the other,
1426          they fail to match.  */
1427       if (args1 == 0 || args2 == 0)
1428         return 0;
1429       mv1 = a1 = TREE_VALUE (args1);
1430       mv2 = a2 = TREE_VALUE (args2);
1431       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1432         mv1 = TYPE_MAIN_VARIANT (mv1);
1433       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1434         mv2 = TYPE_MAIN_VARIANT (mv2);
1435       /* A null pointer instead of a type
1436          means there is supposed to be an argument
1437          but nothing is specified about what type it has.
1438          So match anything that self-promotes.  */
1439       if (a1 == 0)
1440         {
1441           if (c_type_promotes_to (a2) != a2)
1442             return 0;
1443         }
1444       else if (a2 == 0)
1445         {
1446           if (c_type_promotes_to (a1) != a1)
1447             return 0;
1448         }
1449       /* If one of the lists has an error marker, ignore this arg.  */
1450       else if (TREE_CODE (a1) == ERROR_MARK
1451                || TREE_CODE (a2) == ERROR_MARK)
1452         ;
1453       else if (!(newval = comptypes_internal (mv1, mv2)))
1454         {
1455           /* Allow  wait (union {union wait *u; int *i} *)
1456              and  wait (union wait *)  to be compatible.  */
1457           if (TREE_CODE (a1) == UNION_TYPE
1458               && (TYPE_NAME (a1) == 0
1459                   || TYPE_TRANSPARENT_UNION (a1))
1460               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1461               && tree_int_cst_equal (TYPE_SIZE (a1),
1462                                      TYPE_SIZE (a2)))
1463             {
1464               tree memb;
1465               for (memb = TYPE_FIELDS (a1);
1466                    memb; memb = TREE_CHAIN (memb))
1467                 {
1468                   tree mv3 = TREE_TYPE (memb);
1469                   if (mv3 && mv3 != error_mark_node
1470                       && TREE_CODE (mv3) != ARRAY_TYPE)
1471                     mv3 = TYPE_MAIN_VARIANT (mv3);
1472                   if (comptypes_internal (mv3, mv2))
1473                     break;
1474                 }
1475               if (memb == 0)
1476                 return 0;
1477             }
1478           else if (TREE_CODE (a2) == UNION_TYPE
1479                    && (TYPE_NAME (a2) == 0
1480                        || TYPE_TRANSPARENT_UNION (a2))
1481                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1482                    && tree_int_cst_equal (TYPE_SIZE (a2),
1483                                           TYPE_SIZE (a1)))
1484             {
1485               tree memb;
1486               for (memb = TYPE_FIELDS (a2);
1487                    memb; memb = TREE_CHAIN (memb))
1488                 {
1489                   tree mv3 = TREE_TYPE (memb);
1490                   if (mv3 && mv3 != error_mark_node
1491                       && TREE_CODE (mv3) != ARRAY_TYPE)
1492                     mv3 = TYPE_MAIN_VARIANT (mv3);
1493                   if (comptypes_internal (mv3, mv1))
1494                     break;
1495                 }
1496               if (memb == 0)
1497                 return 0;
1498             }
1499           else
1500             return 0;
1501         }
1502
1503       /* comptypes said ok, but record if it said to warn.  */
1504       if (newval > val)
1505         val = newval;
1506
1507       args1 = TREE_CHAIN (args1);
1508       args2 = TREE_CHAIN (args2);
1509     }
1510 }
1511 \f
1512 /* Compute the size to increment a pointer by.  */
1513
1514 static tree
1515 c_size_in_bytes (const_tree type)
1516 {
1517   enum tree_code code = TREE_CODE (type);
1518
1519   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1520     return size_one_node;
1521
1522   if (!COMPLETE_OR_VOID_TYPE_P (type))
1523     {
1524       error ("arithmetic on pointer to an incomplete type");
1525       return size_one_node;
1526     }
1527
1528   /* Convert in case a char is more than one unit.  */
1529   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1530                      size_int (TYPE_PRECISION (char_type_node)
1531                                / BITS_PER_UNIT));
1532 }
1533 \f
1534 /* Return either DECL or its known constant value (if it has one).  */
1535
1536 tree
1537 decl_constant_value (tree decl)
1538 {
1539   if (/* Don't change a variable array bound or initial value to a constant
1540          in a place where a variable is invalid.  Note that DECL_INITIAL
1541          isn't valid for a PARM_DECL.  */
1542       current_function_decl != 0
1543       && TREE_CODE (decl) != PARM_DECL
1544       && !TREE_THIS_VOLATILE (decl)
1545       && TREE_READONLY (decl)
1546       && DECL_INITIAL (decl) != 0
1547       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1548       /* This is invalid if initial value is not constant.
1549          If it has either a function call, a memory reference,
1550          or a variable, then re-evaluating it could give different results.  */
1551       && TREE_CONSTANT (DECL_INITIAL (decl))
1552       /* Check for cases where this is sub-optimal, even though valid.  */
1553       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1554     return DECL_INITIAL (decl);
1555   return decl;
1556 }
1557
1558 /* Return either DECL or its known constant value (if it has one), but
1559    return DECL if pedantic or DECL has mode BLKmode.  This is for
1560    bug-compatibility with the old behavior of decl_constant_value
1561    (before GCC 3.0); every use of this function is a bug and it should
1562    be removed before GCC 3.1.  It is not appropriate to use pedantic
1563    in a way that affects optimization, and BLKmode is probably not the
1564    right test for avoiding misoptimizations either.  */
1565
1566 static tree
1567 decl_constant_value_for_broken_optimization (tree decl)
1568 {
1569   tree ret;
1570
1571   if (pedantic || DECL_MODE (decl) == BLKmode)
1572     return decl;
1573
1574   ret = decl_constant_value (decl);
1575   /* Avoid unwanted tree sharing between the initializer and current
1576      function's body where the tree can be modified e.g. by the
1577      gimplifier.  */
1578   if (ret != decl && TREE_STATIC (decl))
1579     ret = unshare_expr (ret);
1580   return ret;
1581 }
1582
1583 /* Convert the array expression EXP to a pointer.  */
1584 static tree
1585 array_to_pointer_conversion (tree exp)
1586 {
1587   tree orig_exp = exp;
1588   tree type = TREE_TYPE (exp);
1589   tree adr;
1590   tree restype = TREE_TYPE (type);
1591   tree ptrtype;
1592
1593   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1594
1595   STRIP_TYPE_NOPS (exp);
1596
1597   if (TREE_NO_WARNING (orig_exp))
1598     TREE_NO_WARNING (exp) = 1;
1599
1600   ptrtype = build_pointer_type (restype);
1601
1602   if (TREE_CODE (exp) == INDIRECT_REF)
1603     return convert (ptrtype, TREE_OPERAND (exp, 0));
1604
1605   if (TREE_CODE (exp) == VAR_DECL)
1606     {
1607       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1608          ADDR_EXPR because it's the best way of representing what
1609          happens in C when we take the address of an array and place
1610          it in a pointer to the element type.  */
1611       adr = build1 (ADDR_EXPR, ptrtype, exp);
1612       if (!c_mark_addressable (exp))
1613         return error_mark_node;
1614       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1615       return adr;
1616     }
1617
1618   /* This way is better for a COMPONENT_REF since it can
1619      simplify the offset for a component.  */
1620   adr = build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 1);
1621   return convert (ptrtype, adr);
1622 }
1623
1624 /* Convert the function expression EXP to a pointer.  */
1625 static tree
1626 function_to_pointer_conversion (tree exp)
1627 {
1628   tree orig_exp = exp;
1629
1630   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1631
1632   STRIP_TYPE_NOPS (exp);
1633
1634   if (TREE_NO_WARNING (orig_exp))
1635     TREE_NO_WARNING (exp) = 1;
1636
1637   return build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 0);
1638 }
1639
1640 /* Perform the default conversion of arrays and functions to pointers.
1641    Return the result of converting EXP.  For any other expression, just
1642    return EXP after removing NOPs.  */
1643
1644 struct c_expr
1645 default_function_array_conversion (struct c_expr exp)
1646 {
1647   tree orig_exp = exp.value;
1648   tree type = TREE_TYPE (exp.value);
1649   enum tree_code code = TREE_CODE (type);
1650
1651   switch (code)
1652     {
1653     case ARRAY_TYPE:
1654       {
1655         bool not_lvalue = false;
1656         bool lvalue_array_p;
1657
1658         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1659                 || CONVERT_EXPR_P (exp.value))
1660                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1661           {
1662             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1663               not_lvalue = true;
1664             exp.value = TREE_OPERAND (exp.value, 0);
1665           }
1666
1667         if (TREE_NO_WARNING (orig_exp))
1668           TREE_NO_WARNING (exp.value) = 1;
1669
1670         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1671         if (!flag_isoc99 && !lvalue_array_p)
1672           {
1673             /* Before C99, non-lvalue arrays do not decay to pointers.
1674                Normally, using such an array would be invalid; but it can
1675                be used correctly inside sizeof or as a statement expression.
1676                Thus, do not give an error here; an error will result later.  */
1677             return exp;
1678           }
1679
1680         exp.value = array_to_pointer_conversion (exp.value);
1681       }
1682       break;
1683     case FUNCTION_TYPE:
1684       exp.value = function_to_pointer_conversion (exp.value);
1685       break;
1686     default:
1687       STRIP_TYPE_NOPS (exp.value);
1688       if (TREE_NO_WARNING (orig_exp))
1689         TREE_NO_WARNING (exp.value) = 1;
1690       break;
1691     }
1692
1693   return exp;
1694 }
1695
1696
1697 /* EXP is an expression of integer type.  Apply the integer promotions
1698    to it and return the promoted value.  */
1699
1700 tree
1701 perform_integral_promotions (tree exp)
1702 {
1703   tree type = TREE_TYPE (exp);
1704   enum tree_code code = TREE_CODE (type);
1705
1706   gcc_assert (INTEGRAL_TYPE_P (type));
1707
1708   /* Normally convert enums to int,
1709      but convert wide enums to something wider.  */
1710   if (code == ENUMERAL_TYPE)
1711     {
1712       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1713                                           TYPE_PRECISION (integer_type_node)),
1714                                      ((TYPE_PRECISION (type)
1715                                        >= TYPE_PRECISION (integer_type_node))
1716                                       && TYPE_UNSIGNED (type)));
1717
1718       return convert (type, exp);
1719     }
1720
1721   /* ??? This should no longer be needed now bit-fields have their
1722      proper types.  */
1723   if (TREE_CODE (exp) == COMPONENT_REF
1724       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1725       /* If it's thinner than an int, promote it like a
1726          c_promoting_integer_type_p, otherwise leave it alone.  */
1727       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1728                                TYPE_PRECISION (integer_type_node)))
1729     return convert (integer_type_node, exp);
1730
1731   if (c_promoting_integer_type_p (type))
1732     {
1733       /* Preserve unsignedness if not really getting any wider.  */
1734       if (TYPE_UNSIGNED (type)
1735           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1736         return convert (unsigned_type_node, exp);
1737
1738       return convert (integer_type_node, exp);
1739     }
1740
1741   return exp;
1742 }
1743
1744
1745 /* Perform default promotions for C data used in expressions.
1746    Enumeral types or short or char are converted to int.
1747    In addition, manifest constants symbols are replaced by their values.  */
1748
1749 tree
1750 default_conversion (tree exp)
1751 {
1752   tree orig_exp;
1753   tree type = TREE_TYPE (exp);
1754   enum tree_code code = TREE_CODE (type);
1755
1756   /* Functions and arrays have been converted during parsing.  */
1757   gcc_assert (code != FUNCTION_TYPE);
1758   if (code == ARRAY_TYPE)
1759     return exp;
1760
1761   /* Constants can be used directly unless they're not loadable.  */
1762   if (TREE_CODE (exp) == CONST_DECL)
1763     exp = DECL_INITIAL (exp);
1764
1765   /* Replace a nonvolatile const static variable with its value unless
1766      it is an array, in which case we must be sure that taking the
1767      address of the array produces consistent results.  */
1768   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1769     {
1770       exp = decl_constant_value_for_broken_optimization (exp);
1771       type = TREE_TYPE (exp);
1772     }
1773
1774   /* Strip no-op conversions.  */
1775   orig_exp = exp;
1776   STRIP_TYPE_NOPS (exp);
1777
1778   if (TREE_NO_WARNING (orig_exp))
1779     TREE_NO_WARNING (exp) = 1;
1780
1781   if (code == VOID_TYPE)
1782     {
1783       error ("void value not ignored as it ought to be");
1784       return error_mark_node;
1785     }
1786
1787   exp = require_complete_type (exp);
1788   if (exp == error_mark_node)
1789     return error_mark_node;
1790
1791   if (INTEGRAL_TYPE_P (type))
1792     return perform_integral_promotions (exp);
1793
1794   return exp;
1795 }
1796 \f
1797 /* Look up COMPONENT in a structure or union DECL.
1798
1799    If the component name is not found, returns NULL_TREE.  Otherwise,
1800    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1801    stepping down the chain to the component, which is in the last
1802    TREE_VALUE of the list.  Normally the list is of length one, but if
1803    the component is embedded within (nested) anonymous structures or
1804    unions, the list steps down the chain to the component.  */
1805
1806 static tree
1807 lookup_field (tree decl, tree component)
1808 {
1809   tree type = TREE_TYPE (decl);
1810   tree field;
1811
1812   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1813      to the field elements.  Use a binary search on this array to quickly
1814      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1815      will always be set for structures which have many elements.  */
1816
1817   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1818     {
1819       int bot, top, half;
1820       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1821
1822       field = TYPE_FIELDS (type);
1823       bot = 0;
1824       top = TYPE_LANG_SPECIFIC (type)->s->len;
1825       while (top - bot > 1)
1826         {
1827           half = (top - bot + 1) >> 1;
1828           field = field_array[bot+half];
1829
1830           if (DECL_NAME (field) == NULL_TREE)
1831             {
1832               /* Step through all anon unions in linear fashion.  */
1833               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1834                 {
1835                   field = field_array[bot++];
1836                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1837                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1838                     {
1839                       tree anon = lookup_field (field, component);
1840
1841                       if (anon)
1842                         return tree_cons (NULL_TREE, field, anon);
1843                     }
1844                 }
1845
1846               /* Entire record is only anon unions.  */
1847               if (bot > top)
1848                 return NULL_TREE;
1849
1850               /* Restart the binary search, with new lower bound.  */
1851               continue;
1852             }
1853
1854           if (DECL_NAME (field) == component)
1855             break;
1856           if (DECL_NAME (field) < component)
1857             bot += half;
1858           else
1859             top = bot + half;
1860         }
1861
1862       if (DECL_NAME (field_array[bot]) == component)
1863         field = field_array[bot];
1864       else if (DECL_NAME (field) != component)
1865         return NULL_TREE;
1866     }
1867   else
1868     {
1869       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1870         {
1871           if (DECL_NAME (field) == NULL_TREE
1872               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1873                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1874             {
1875               tree anon = lookup_field (field, component);
1876
1877               if (anon)
1878                 return tree_cons (NULL_TREE, field, anon);
1879             }
1880
1881           if (DECL_NAME (field) == component)
1882             break;
1883         }
1884
1885       if (field == NULL_TREE)
1886         return NULL_TREE;
1887     }
1888
1889   return tree_cons (NULL_TREE, field, NULL_TREE);
1890 }
1891
1892 /* Make an expression to refer to the COMPONENT field of
1893    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1894
1895 tree
1896 build_component_ref (tree datum, tree component)
1897 {
1898   tree type = TREE_TYPE (datum);
1899   enum tree_code code = TREE_CODE (type);
1900   tree field = NULL;
1901   tree ref;
1902
1903   if (!objc_is_public (datum, component))
1904     return error_mark_node;
1905
1906   /* See if there is a field or component with name COMPONENT.  */
1907
1908   if (code == RECORD_TYPE || code == UNION_TYPE)
1909     {
1910       if (!COMPLETE_TYPE_P (type))
1911         {
1912           c_incomplete_type_error (NULL_TREE, type);
1913           return error_mark_node;
1914         }
1915
1916       field = lookup_field (datum, component);
1917
1918       if (!field)
1919         {
1920           error ("%qT has no member named %qE", type, component);
1921           return error_mark_node;
1922         }
1923
1924       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1925          This might be better solved in future the way the C++ front
1926          end does it - by giving the anonymous entities each a
1927          separate name and type, and then have build_component_ref
1928          recursively call itself.  We can't do that here.  */
1929       do
1930         {
1931           tree subdatum = TREE_VALUE (field);
1932           int quals;
1933           tree subtype;
1934
1935           if (TREE_TYPE (subdatum) == error_mark_node)
1936             return error_mark_node;
1937
1938           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1939           quals |= TYPE_QUALS (TREE_TYPE (datum));
1940           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1941
1942           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1943                         NULL_TREE);
1944           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1945             TREE_READONLY (ref) = 1;
1946           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1947             TREE_THIS_VOLATILE (ref) = 1;
1948
1949           if (TREE_DEPRECATED (subdatum))
1950             warn_deprecated_use (subdatum);
1951
1952           datum = ref;
1953
1954           field = TREE_CHAIN (field);
1955         }
1956       while (field);
1957
1958       return ref;
1959     }
1960   else if (code != ERROR_MARK)
1961     error ("request for member %qE in something not a structure or union",
1962            component);
1963
1964   return error_mark_node;
1965 }
1966 \f
1967 /* Given an expression PTR for a pointer, return an expression
1968    for the value pointed to.
1969    ERRORSTRING is the name of the operator to appear in error messages.
1970
1971    LOC is the location to use for the generated tree.  */
1972
1973 tree
1974 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
1975 {
1976   tree pointer = default_conversion (ptr);
1977   tree type = TREE_TYPE (pointer);
1978   tree ref;
1979
1980   if (TREE_CODE (type) == POINTER_TYPE)
1981     {
1982       if (CONVERT_EXPR_P (pointer)
1983           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1984         {
1985           /* If a warning is issued, mark it to avoid duplicates from
1986              the backend.  This only needs to be done at
1987              warn_strict_aliasing > 2.  */
1988           if (warn_strict_aliasing > 2)
1989             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1990                                          type, TREE_OPERAND (pointer, 0)))
1991               TREE_NO_WARNING (pointer) = 1;
1992         }
1993
1994       if (TREE_CODE (pointer) == ADDR_EXPR
1995           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1996               == TREE_TYPE (type)))
1997         {
1998           ref = TREE_OPERAND (pointer, 0);
1999           protected_set_expr_location (ref, loc);
2000           return ref;
2001         }
2002       else
2003         {
2004           tree t = TREE_TYPE (type);
2005
2006           ref = build1 (INDIRECT_REF, t, pointer);
2007
2008           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2009             {
2010               error_at (loc, "dereferencing pointer to incomplete type");
2011               return error_mark_node;
2012             }
2013           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2014             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2015
2016           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2017              so that we get the proper error message if the result is used
2018              to assign to.  Also, &* is supposed to be a no-op.
2019              And ANSI C seems to specify that the type of the result
2020              should be the const type.  */
2021           /* A de-reference of a pointer to const is not a const.  It is valid
2022              to change it via some other pointer.  */
2023           TREE_READONLY (ref) = TYPE_READONLY (t);
2024           TREE_SIDE_EFFECTS (ref)
2025             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2026           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2027           protected_set_expr_location (ref, loc);
2028           return ref;
2029         }
2030     }
2031   else if (TREE_CODE (pointer) != ERROR_MARK)
2032     error_at (loc,
2033               "invalid type argument of %qs (have %qT)", errorstring, type);
2034   return error_mark_node;
2035 }
2036
2037 /* This handles expressions of the form "a[i]", which denotes
2038    an array reference.
2039
2040    This is logically equivalent in C to *(a+i), but we may do it differently.
2041    If A is a variable or a member, we generate a primitive ARRAY_REF.
2042    This avoids forcing the array out of registers, and can work on
2043    arrays that are not lvalues (for example, members of structures returned
2044    by functions).
2045
2046    LOC is the location to use for the returned expression.  */
2047
2048 tree
2049 build_array_ref (tree array, tree index, location_t loc)
2050 {
2051   tree ret;
2052   bool swapped = false;
2053   if (TREE_TYPE (array) == error_mark_node
2054       || TREE_TYPE (index) == error_mark_node)
2055     return error_mark_node;
2056
2057   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2058       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2059     {
2060       tree temp;
2061       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2062           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2063         {
2064           error_at (loc, "subscripted value is neither array nor pointer");
2065           return error_mark_node;
2066         }
2067       temp = array;
2068       array = index;
2069       index = temp;
2070       swapped = true;
2071     }
2072
2073   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2074     {
2075       error_at (loc, "array subscript is not an integer");
2076       return error_mark_node;
2077     }
2078
2079   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2080     {
2081       error_at (loc, "subscripted value is pointer to function");
2082       return error_mark_node;
2083     }
2084
2085   /* ??? Existing practice has been to warn only when the char
2086      index is syntactically the index, not for char[array].  */
2087   if (!swapped)
2088      warn_array_subscript_with_type_char (index);
2089
2090   /* Apply default promotions *after* noticing character types.  */
2091   index = default_conversion (index);
2092
2093   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2094
2095   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2096     {
2097       tree rval, type;
2098
2099       /* An array that is indexed by a non-constant
2100          cannot be stored in a register; we must be able to do
2101          address arithmetic on its address.
2102          Likewise an array of elements of variable size.  */
2103       if (TREE_CODE (index) != INTEGER_CST
2104           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2105               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2106         {
2107           if (!c_mark_addressable (array))
2108             return error_mark_node;
2109         }
2110       /* An array that is indexed by a constant value which is not within
2111          the array bounds cannot be stored in a register either; because we
2112          would get a crash in store_bit_field/extract_bit_field when trying
2113          to access a non-existent part of the register.  */
2114       if (TREE_CODE (index) == INTEGER_CST
2115           && TYPE_DOMAIN (TREE_TYPE (array))
2116           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2117         {
2118           if (!c_mark_addressable (array))
2119             return error_mark_node;
2120         }
2121
2122       if (pedantic)
2123         {
2124           tree foo = array;
2125           while (TREE_CODE (foo) == COMPONENT_REF)
2126             foo = TREE_OPERAND (foo, 0);
2127           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2128             pedwarn (loc, OPT_pedantic,
2129                      "ISO C forbids subscripting %<register%> array");
2130           else if (!flag_isoc99 && !lvalue_p (foo))
2131             pedwarn (loc, OPT_pedantic,
2132                      "ISO C90 forbids subscripting non-lvalue array");
2133         }
2134
2135       type = TREE_TYPE (TREE_TYPE (array));
2136       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2137       /* Array ref is const/volatile if the array elements are
2138          or if the array is.  */
2139       TREE_READONLY (rval)
2140         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2141             | TREE_READONLY (array));
2142       TREE_SIDE_EFFECTS (rval)
2143         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2144             | TREE_SIDE_EFFECTS (array));
2145       TREE_THIS_VOLATILE (rval)
2146         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2147             /* This was added by rms on 16 Nov 91.
2148                It fixes  vol struct foo *a;  a->elts[1]
2149                in an inline function.
2150                Hope it doesn't break something else.  */
2151             | TREE_THIS_VOLATILE (array));
2152       ret = require_complete_type (fold (rval));
2153       protected_set_expr_location (ret, loc);
2154       return ret;
2155     }
2156   else
2157     {
2158       tree ar = default_conversion (array);
2159
2160       if (ar == error_mark_node)
2161         return ar;
2162
2163       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2164       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2165
2166       return build_indirect_ref
2167         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2168          "array indexing");
2169     }
2170 }
2171 \f
2172 /* Build an external reference to identifier ID.  FUN indicates
2173    whether this will be used for a function call.  LOC is the source
2174    location of the identifier.  */
2175 tree
2176 build_external_ref (tree id, int fun, location_t loc)
2177 {
2178   tree ref;
2179   tree decl = lookup_name (id);
2180
2181   /* In Objective-C, an instance variable (ivar) may be preferred to
2182      whatever lookup_name() found.  */
2183   decl = objc_lookup_ivar (decl, id);
2184
2185   if (decl && decl != error_mark_node)
2186     ref = decl;
2187   else if (fun)
2188     /* Implicit function declaration.  */
2189     ref = implicitly_declare (id);
2190   else if (decl == error_mark_node)
2191     /* Don't complain about something that's already been
2192        complained about.  */
2193     return error_mark_node;
2194   else
2195     {
2196       undeclared_variable (id, loc);
2197       return error_mark_node;
2198     }
2199
2200   if (TREE_TYPE (ref) == error_mark_node)
2201     return error_mark_node;
2202
2203   if (TREE_DEPRECATED (ref))
2204     warn_deprecated_use (ref);
2205
2206   /* Recursive call does not count as usage.  */
2207   if (ref != current_function_decl)
2208     {
2209       TREE_USED (ref) = 1;
2210     }
2211
2212   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2213     {
2214       if (!in_sizeof && !in_typeof)
2215         C_DECL_USED (ref) = 1;
2216       else if (DECL_INITIAL (ref) == 0
2217                && DECL_EXTERNAL (ref)
2218                && !TREE_PUBLIC (ref))
2219         record_maybe_used_decl (ref);
2220     }
2221
2222   if (TREE_CODE (ref) == CONST_DECL)
2223     {
2224       used_types_insert (TREE_TYPE (ref));
2225       ref = DECL_INITIAL (ref);
2226       TREE_CONSTANT (ref) = 1;
2227     }
2228   else if (current_function_decl != 0
2229            && !DECL_FILE_SCOPE_P (current_function_decl)
2230            && (TREE_CODE (ref) == VAR_DECL
2231                || TREE_CODE (ref) == PARM_DECL
2232                || TREE_CODE (ref) == FUNCTION_DECL))
2233     {
2234       tree context = decl_function_context (ref);
2235
2236       if (context != 0 && context != current_function_decl)
2237         DECL_NONLOCAL (ref) = 1;
2238     }
2239   /* C99 6.7.4p3: An inline definition of a function with external
2240      linkage ... shall not contain a reference to an identifier with
2241      internal linkage.  */
2242   else if (current_function_decl != 0
2243            && DECL_DECLARED_INLINE_P (current_function_decl)
2244            && DECL_EXTERNAL (current_function_decl)
2245            && VAR_OR_FUNCTION_DECL_P (ref)
2246            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2247            && ! TREE_PUBLIC (ref)
2248            && DECL_CONTEXT (ref) != current_function_decl)
2249     pedwarn (loc, 0, "%qD is static but used in inline function %qD "
2250              "which is not static", ref, current_function_decl);
2251
2252   return ref;
2253 }
2254
2255 /* Record details of decls possibly used inside sizeof or typeof.  */
2256 struct maybe_used_decl
2257 {
2258   /* The decl.  */
2259   tree decl;
2260   /* The level seen at (in_sizeof + in_typeof).  */
2261   int level;
2262   /* The next one at this level or above, or NULL.  */
2263   struct maybe_used_decl *next;
2264 };
2265
2266 static struct maybe_used_decl *maybe_used_decls;
2267
2268 /* Record that DECL, an undefined static function reference seen
2269    inside sizeof or typeof, might be used if the operand of sizeof is
2270    a VLA type or the operand of typeof is a variably modified
2271    type.  */
2272
2273 static void
2274 record_maybe_used_decl (tree decl)
2275 {
2276   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2277   t->decl = decl;
2278   t->level = in_sizeof + in_typeof;
2279   t->next = maybe_used_decls;
2280   maybe_used_decls = t;
2281 }
2282
2283 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2284    USED is false, just discard them.  If it is true, mark them used
2285    (if no longer inside sizeof or typeof) or move them to the next
2286    level up (if still inside sizeof or typeof).  */
2287
2288 void
2289 pop_maybe_used (bool used)
2290 {
2291   struct maybe_used_decl *p = maybe_used_decls;
2292   int cur_level = in_sizeof + in_typeof;
2293   while (p && p->level > cur_level)
2294     {
2295       if (used)
2296         {
2297           if (cur_level == 0)
2298             C_DECL_USED (p->decl) = 1;
2299           else
2300             p->level = cur_level;
2301         }
2302       p = p->next;
2303     }
2304   if (!used || cur_level == 0)
2305     maybe_used_decls = p;
2306 }
2307
2308 /* Return the result of sizeof applied to EXPR.  */
2309
2310 struct c_expr
2311 c_expr_sizeof_expr (struct c_expr expr)
2312 {
2313   struct c_expr ret;
2314   if (expr.value == error_mark_node)
2315     {
2316       ret.value = error_mark_node;
2317       ret.original_code = ERROR_MARK;
2318       pop_maybe_used (false);
2319     }
2320   else
2321     {
2322       ret.value = c_sizeof (TREE_TYPE (expr.value));
2323       ret.original_code = ERROR_MARK;
2324       if (c_vla_type_p (TREE_TYPE (expr.value)))
2325         {
2326           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2327           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2328         }
2329       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2330     }
2331   return ret;
2332 }
2333
2334 /* Return the result of sizeof applied to T, a structure for the type
2335    name passed to sizeof (rather than the type itself).  */
2336
2337 struct c_expr
2338 c_expr_sizeof_type (struct c_type_name *t)
2339 {
2340   tree type;
2341   struct c_expr ret;
2342   type = groktypename (t);
2343   ret.value = c_sizeof (type);
2344   ret.original_code = ERROR_MARK;
2345   pop_maybe_used (type != error_mark_node
2346                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2347   return ret;
2348 }
2349
2350 /* Build a function call to function FUNCTION with parameters PARAMS.
2351    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2352    TREE_VALUE of each node is a parameter-expression.
2353    FUNCTION's data type may be a function type or a pointer-to-function.  */
2354
2355 tree
2356 build_function_call (tree function, tree params)
2357 {
2358   tree fntype, fundecl = 0;
2359   tree name = NULL_TREE, result;
2360   tree tem;
2361   int nargs;
2362   tree *argarray;
2363
2364
2365   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2366   STRIP_TYPE_NOPS (function);
2367
2368   /* Convert anything with function type to a pointer-to-function.  */
2369   if (TREE_CODE (function) == FUNCTION_DECL)
2370     {
2371       /* Implement type-directed function overloading for builtins.
2372          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2373          handle all the type checking.  The result is a complete expression
2374          that implements this function call.  */
2375       tem = resolve_overloaded_builtin (function, params);
2376       if (tem)
2377         return tem;
2378
2379       name = DECL_NAME (function);
2380       fundecl = function;
2381     }
2382   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2383     function = function_to_pointer_conversion (function);
2384
2385   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2386      expressions, like those used for ObjC messenger dispatches.  */
2387   function = objc_rewrite_function_call (function, params);
2388
2389   fntype = TREE_TYPE (function);
2390
2391   if (TREE_CODE (fntype) == ERROR_MARK)
2392     return error_mark_node;
2393
2394   if (!(TREE_CODE (fntype) == POINTER_TYPE
2395         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2396     {
2397       error ("called object %qE is not a function", function);
2398       return error_mark_node;
2399     }
2400
2401   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2402     current_function_returns_abnormally = 1;
2403
2404   /* fntype now gets the type of function pointed to.  */
2405   fntype = TREE_TYPE (fntype);
2406
2407   /* Check that the function is called through a compatible prototype.
2408      If it is not, replace the call by a trap, wrapped up in a compound
2409      expression if necessary.  This has the nice side-effect to prevent
2410      the tree-inliner from generating invalid assignment trees which may
2411      blow up in the RTL expander later.  */
2412   if (CONVERT_EXPR_P (function)
2413       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2414       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2415       && !comptypes (fntype, TREE_TYPE (tem)))
2416     {
2417       tree return_type = TREE_TYPE (fntype);
2418       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2419                                        NULL_TREE);
2420
2421       /* This situation leads to run-time undefined behavior.  We can't,
2422          therefore, simply error unless we can prove that all possible
2423          executions of the program must execute the code.  */
2424       if (warning (0, "function called through a non-compatible type"))
2425         /* We can, however, treat "undefined" any way we please.
2426            Call abort to encourage the user to fix the program.  */
2427         inform (input_location, "if this code is reached, the program will abort");
2428
2429       if (VOID_TYPE_P (return_type))
2430         return trap;
2431       else
2432         {
2433           tree rhs;
2434
2435           if (AGGREGATE_TYPE_P (return_type))
2436             rhs = build_compound_literal (return_type,
2437                                           build_constructor (return_type, 0));
2438           else
2439             rhs = fold_convert (return_type, integer_zero_node);
2440
2441           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2442         }
2443     }
2444
2445   /* Convert the parameters to the types declared in the
2446      function prototype, or apply default promotions.  */
2447
2448   nargs = list_length (params);
2449   argarray = (tree *) alloca (nargs * sizeof (tree));
2450   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2451                              params, function, fundecl);
2452   if (nargs < 0)
2453     return error_mark_node;
2454
2455   /* Check that arguments to builtin functions match the expectations.  */
2456   if (fundecl
2457       && DECL_BUILT_IN (fundecl)
2458       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2459       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2460     return error_mark_node;
2461
2462   /* Check that the arguments to the function are valid.  */
2463   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2464                             TYPE_ARG_TYPES (fntype));
2465
2466   if (require_constant_value)
2467     {
2468       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2469                                                   function, nargs, argarray);
2470       if (TREE_CONSTANT (result)
2471           && (name == NULL_TREE
2472               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2473         pedwarn_init (input_location, 0, "initializer element is not constant");
2474     }
2475   else
2476     result = fold_build_call_array (TREE_TYPE (fntype),
2477                                     function, nargs, argarray);
2478
2479   if (VOID_TYPE_P (TREE_TYPE (result)))
2480     return result;
2481   return require_complete_type (result);
2482 }
2483 \f
2484 /* Convert the argument expressions in the list VALUES
2485    to the types in the list TYPELIST.  The resulting arguments are
2486    stored in the array ARGARRAY which has size NARGS.
2487
2488    If TYPELIST is exhausted, or when an element has NULL as its type,
2489    perform the default conversions.
2490
2491    PARMLIST is the chain of parm decls for the function being called.
2492    It may be 0, if that info is not available.
2493    It is used only for generating error messages.
2494
2495    FUNCTION is a tree for the called function.  It is used only for
2496    error messages, where it is formatted with %qE.
2497
2498    This is also where warnings about wrong number of args are generated.
2499
2500    VALUES is a chain of TREE_LIST nodes with the elements of the list
2501    in the TREE_VALUE slots of those nodes.
2502
2503    Returns the actual number of arguments processed (which may be less
2504    than NARGS in some error situations), or -1 on failure.  */
2505
2506 static int
2507 convert_arguments (int nargs, tree *argarray,
2508                    tree typelist, tree values, tree function, tree fundecl)
2509 {
2510   tree typetail, valtail;
2511   int parmnum;
2512   const bool type_generic = fundecl
2513     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2514   tree selector;
2515
2516   /* Change pointer to function to the function itself for
2517      diagnostics.  */
2518   if (TREE_CODE (function) == ADDR_EXPR
2519       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2520     function = TREE_OPERAND (function, 0);
2521
2522   /* Handle an ObjC selector specially for diagnostics.  */
2523   selector = objc_message_selector ();
2524
2525   /* Scan the given expressions and types, producing individual
2526      converted arguments and storing them in ARGARRAY.  */
2527
2528   for (valtail = values, typetail = typelist, parmnum = 0;
2529        valtail;
2530        valtail = TREE_CHAIN (valtail), parmnum++)
2531     {
2532       tree type = typetail ? TREE_VALUE (typetail) : 0;
2533       tree val = TREE_VALUE (valtail);
2534       tree rname = function;
2535       int argnum = parmnum + 1;
2536       const char *invalid_func_diag;
2537
2538       if (type == void_type_node)
2539         {
2540           error ("too many arguments to function %qE", function);
2541           return parmnum;
2542         }
2543
2544       if (selector && argnum > 2)
2545         {
2546           rname = selector;
2547           argnum -= 2;
2548         }
2549
2550       STRIP_TYPE_NOPS (val);
2551
2552       val = require_complete_type (val);
2553
2554       if (type != 0)
2555         {
2556           /* Formal parm type is specified by a function prototype.  */
2557           tree parmval;
2558
2559           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2560             {
2561               error ("type of formal parameter %d is incomplete", parmnum + 1);
2562               parmval = val;
2563             }
2564           else
2565             {
2566               /* Optionally warn about conversions that
2567                  differ from the default conversions.  */
2568               if (warn_traditional_conversion || warn_traditional)
2569                 {
2570                   unsigned int formal_prec = TYPE_PRECISION (type);
2571
2572                   if (INTEGRAL_TYPE_P (type)
2573                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2574                     warning (0, "passing argument %d of %qE as integer "
2575                              "rather than floating due to prototype",
2576                              argnum, rname);
2577                   if (INTEGRAL_TYPE_P (type)
2578                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2579                     warning (0, "passing argument %d of %qE as integer "
2580                              "rather than complex due to prototype",
2581                              argnum, rname);
2582                   else if (TREE_CODE (type) == COMPLEX_TYPE
2583                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2584                     warning (0, "passing argument %d of %qE as complex "
2585                              "rather than floating due to prototype",
2586                              argnum, rname);
2587                   else if (TREE_CODE (type) == REAL_TYPE
2588                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2589                     warning (0, "passing argument %d of %qE as floating "
2590                              "rather than integer due to prototype",
2591                              argnum, rname);
2592                   else if (TREE_CODE (type) == COMPLEX_TYPE
2593                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2594                     warning (0, "passing argument %d of %qE as complex "
2595                              "rather than integer due to prototype",
2596                              argnum, rname);
2597                   else if (TREE_CODE (type) == REAL_TYPE
2598                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2599                     warning (0, "passing argument %d of %qE as floating "
2600                              "rather than complex due to prototype",
2601                              argnum, rname);
2602                   /* ??? At some point, messages should be written about
2603                      conversions between complex types, but that's too messy
2604                      to do now.  */
2605                   else if (TREE_CODE (type) == REAL_TYPE
2606                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2607                     {
2608                       /* Warn if any argument is passed as `float',
2609                          since without a prototype it would be `double'.  */
2610                       if (formal_prec == TYPE_PRECISION (float_type_node)
2611                           && type != dfloat32_type_node)
2612                         warning (0, "passing argument %d of %qE as %<float%> "
2613                                  "rather than %<double%> due to prototype",
2614                                  argnum, rname);
2615
2616                       /* Warn if mismatch between argument and prototype
2617                          for decimal float types.  Warn of conversions with
2618                          binary float types and of precision narrowing due to
2619                          prototype. */
2620                       else if (type != TREE_TYPE (val)
2621                                && (type == dfloat32_type_node
2622                                    || type == dfloat64_type_node
2623                                    || type == dfloat128_type_node
2624                                    || TREE_TYPE (val) == dfloat32_type_node
2625                                    || TREE_TYPE (val) == dfloat64_type_node
2626                                    || TREE_TYPE (val) == dfloat128_type_node)
2627                                && (formal_prec
2628                                    <= TYPE_PRECISION (TREE_TYPE (val))
2629                                    || (type == dfloat128_type_node
2630                                        && (TREE_TYPE (val)
2631                                            != dfloat64_type_node
2632                                            && (TREE_TYPE (val)
2633                                                != dfloat32_type_node)))
2634                                    || (type == dfloat64_type_node
2635                                        && (TREE_TYPE (val)
2636                                            != dfloat32_type_node))))
2637                         warning (0, "passing argument %d of %qE as %qT "
2638                                  "rather than %qT due to prototype",
2639                                  argnum, rname, type, TREE_TYPE (val));
2640
2641                     }
2642                   /* Detect integer changing in width or signedness.
2643                      These warnings are only activated with
2644                      -Wtraditional-conversion, not with -Wtraditional.  */
2645                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2646                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2647                     {
2648                       tree would_have_been = default_conversion (val);
2649                       tree type1 = TREE_TYPE (would_have_been);
2650
2651                       if (TREE_CODE (type) == ENUMERAL_TYPE
2652                           && (TYPE_MAIN_VARIANT (type)
2653                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2654                         /* No warning if function asks for enum
2655                            and the actual arg is that enum type.  */
2656                         ;
2657                       else if (formal_prec != TYPE_PRECISION (type1))
2658                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2659                                  "with different width due to prototype",
2660                                  argnum, rname);
2661                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2662                         ;
2663                       /* Don't complain if the formal parameter type
2664                          is an enum, because we can't tell now whether
2665                          the value was an enum--even the same enum.  */
2666                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2667                         ;
2668                       else if (TREE_CODE (val) == INTEGER_CST
2669                                && int_fits_type_p (val, type))
2670                         /* Change in signedness doesn't matter
2671                            if a constant value is unaffected.  */
2672                         ;
2673                       /* If the value is extended from a narrower
2674                          unsigned type, it doesn't matter whether we
2675                          pass it as signed or unsigned; the value
2676                          certainly is the same either way.  */
2677                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2678                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2679                         ;
2680                       else if (TYPE_UNSIGNED (type))
2681                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2682                                  "as unsigned due to prototype",
2683                                  argnum, rname);
2684                       else
2685                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2686                                  "as signed due to prototype", argnum, rname);
2687                     }
2688                 }
2689
2690               parmval = convert_for_assignment (type, val, ic_argpass,
2691                                                 fundecl, function,
2692                                                 parmnum + 1);
2693
2694               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2695                   && INTEGRAL_TYPE_P (type)
2696                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2697                 parmval = default_conversion (parmval);
2698             }
2699           argarray[parmnum] = parmval;
2700         }
2701       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2702                && (TYPE_PRECISION (TREE_TYPE (val))
2703                    < TYPE_PRECISION (double_type_node))
2704                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2705         {
2706           if (type_generic)
2707             argarray[parmnum] = val;
2708           else
2709             /* Convert `float' to `double'.  */
2710             argarray[parmnum] = convert (double_type_node, val);
2711         }
2712       else if ((invalid_func_diag =
2713                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2714         {
2715           error (invalid_func_diag);
2716           return -1;
2717         }
2718       else
2719         /* Convert `short' and `char' to full-size `int'.  */
2720         argarray[parmnum] = default_conversion (val);
2721
2722       if (typetail)
2723         typetail = TREE_CHAIN (typetail);
2724     }
2725
2726   gcc_assert (parmnum == nargs);
2727
2728   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2729     {
2730       error ("too few arguments to function %qE", function);
2731       return -1;
2732     }
2733
2734   return parmnum;
2735 }
2736 \f
2737 /* This is the entry point used by the parser to build unary operators
2738    in the input.  CODE, a tree_code, specifies the unary operator, and
2739    ARG is the operand.  For unary plus, the C parser currently uses
2740    CONVERT_EXPR for code.
2741
2742    LOC is the location to use for the tree generated.
2743 */
2744
2745 struct c_expr
2746 parser_build_unary_op (enum tree_code code, struct c_expr arg, location_t loc)
2747 {
2748   struct c_expr result;
2749
2750   result.value = build_unary_op (loc, code, arg.value, 0);
2751   result.original_code = code;
2752
2753   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2754     overflow_warning (result.value);
2755
2756   return result;
2757 }
2758
2759 /* This is the entry point used by the parser to build binary operators
2760    in the input.  CODE, a tree_code, specifies the binary operator, and
2761    ARG1 and ARG2 are the operands.  In addition to constructing the
2762    expression, we check for operands that were written with other binary
2763    operators in a way that is likely to confuse the user.
2764
2765    LOCATION is the location of the binary operator.  */
2766
2767 struct c_expr
2768 parser_build_binary_op (location_t location, enum tree_code code,
2769                         struct c_expr arg1, struct c_expr arg2)
2770 {
2771   struct c_expr result;
2772
2773   enum tree_code code1 = arg1.original_code;
2774   enum tree_code code2 = arg2.original_code;
2775
2776   result.value = build_binary_op (location, code,
2777                                   arg1.value, arg2.value, 1);
2778   result.original_code = code;
2779
2780   if (TREE_CODE (result.value) == ERROR_MARK)
2781     return result;
2782
2783   if (location != UNKNOWN_LOCATION)
2784     protected_set_expr_location (result.value, location);
2785
2786   /* Check for cases such as x+y<<z which users are likely
2787      to misinterpret.  */
2788   if (warn_parentheses)
2789     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
2790
2791   if (TREE_CODE_CLASS (code1) != tcc_comparison)
2792     warn_logical_operator (code, arg1.value, arg2.value);
2793
2794   /* Warn about comparisons against string literals, with the exception
2795      of testing for equality or inequality of a string literal with NULL.  */
2796   if (code == EQ_EXPR || code == NE_EXPR)
2797     {
2798       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2799           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2800         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2801     }
2802   else if (TREE_CODE_CLASS (code) == tcc_comparison
2803            && (code1 == STRING_CST || code2 == STRING_CST))
2804     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2805
2806   if (TREE_OVERFLOW_P (result.value)
2807       && !TREE_OVERFLOW_P (arg1.value)
2808       && !TREE_OVERFLOW_P (arg2.value))
2809     overflow_warning (result.value);
2810
2811   return result;
2812 }
2813 \f
2814 /* Return a tree for the difference of pointers OP0 and OP1.
2815    The resulting tree has type int.  */
2816
2817 static tree
2818 pointer_diff (tree op0, tree op1)
2819 {
2820   tree restype = ptrdiff_type_node;
2821
2822   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2823   tree con0, con1, lit0, lit1;
2824   tree orig_op1 = op1;
2825
2826   if (TREE_CODE (target_type) == VOID_TYPE)
2827     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2828              "pointer of type %<void *%> used in subtraction");
2829   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2830     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2831              "pointer to a function used in subtraction");
2832
2833   /* If the conversion to ptrdiff_type does anything like widening or
2834      converting a partial to an integral mode, we get a convert_expression
2835      that is in the way to do any simplifications.
2836      (fold-const.c doesn't know that the extra bits won't be needed.
2837      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2838      different mode in place.)
2839      So first try to find a common term here 'by hand'; we want to cover
2840      at least the cases that occur in legal static initializers.  */
2841   if (CONVERT_EXPR_P (op0)
2842       && (TYPE_PRECISION (TREE_TYPE (op0))
2843           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2844     con0 = TREE_OPERAND (op0, 0);
2845   else
2846     con0 = op0;
2847   if (CONVERT_EXPR_P (op1)
2848       && (TYPE_PRECISION (TREE_TYPE (op1))
2849           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2850     con1 = TREE_OPERAND (op1, 0);
2851   else
2852     con1 = op1;
2853
2854   if (TREE_CODE (con0) == PLUS_EXPR)
2855     {
2856       lit0 = TREE_OPERAND (con0, 1);
2857       con0 = TREE_OPERAND (con0, 0);
2858     }
2859   else
2860     lit0 = integer_zero_node;
2861
2862   if (TREE_CODE (con1) == PLUS_EXPR)
2863     {
2864       lit1 = TREE_OPERAND (con1, 1);
2865       con1 = TREE_OPERAND (con1, 0);
2866     }
2867   else
2868     lit1 = integer_zero_node;
2869
2870   if (operand_equal_p (con0, con1, 0))
2871     {
2872       op0 = lit0;
2873       op1 = lit1;
2874     }
2875
2876
2877   /* First do the subtraction as integers;
2878      then drop through to build the divide operator.
2879      Do not do default conversions on the minus operator
2880      in case restype is a short type.  */
2881
2882   op0 = build_binary_op (input_location,
2883                          MINUS_EXPR, convert (restype, op0),
2884                          convert (restype, op1), 0);
2885   /* This generates an error if op1 is pointer to incomplete type.  */
2886   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2887     error ("arithmetic on pointer to an incomplete type");
2888
2889   /* This generates an error if op0 is pointer to incomplete type.  */
2890   op1 = c_size_in_bytes (target_type);
2891
2892   /* Divide by the size, in easiest possible way.  */
2893   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2894 }
2895 \f
2896 /* Construct and perhaps optimize a tree representation
2897    for a unary operation.  CODE, a tree_code, specifies the operation
2898    and XARG is the operand.
2899    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2900    the default promotions (such as from short to int).
2901    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2902    allows non-lvalues; this is only used to handle conversion of non-lvalue
2903    arrays to pointers in C99.
2904
2905    LOCATION is the location of the operator.  */
2906
2907 tree
2908 build_unary_op (location_t location,
2909                 enum tree_code code, tree xarg, int flag)
2910 {
2911   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2912   tree arg = xarg;
2913   tree argtype = 0;
2914   enum tree_code typecode;
2915   tree val;
2916   tree ret = error_mark_node;
2917   int noconvert = flag;
2918   const char *invalid_op_diag;
2919
2920   if (code != ADDR_EXPR)
2921     arg = require_complete_type (arg);
2922
2923   typecode = TREE_CODE (TREE_TYPE (arg));
2924   if (typecode == ERROR_MARK)
2925     return error_mark_node;
2926   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2927     typecode = INTEGER_TYPE;
2928
2929   if ((invalid_op_diag
2930        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2931     {
2932       error_at (location, invalid_op_diag);
2933       return error_mark_node;
2934     }
2935
2936   switch (code)
2937     {
2938     case CONVERT_EXPR:
2939       /* This is used for unary plus, because a CONVERT_EXPR
2940          is enough to prevent anybody from looking inside for
2941          associativity, but won't generate any code.  */
2942       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2943             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2944             || typecode == VECTOR_TYPE))
2945         {
2946           error_at (location, "wrong type argument to unary plus");
2947           return error_mark_node;
2948         }
2949       else if (!noconvert)
2950         arg = default_conversion (arg);
2951       arg = non_lvalue (arg);
2952       break;
2953
2954     case NEGATE_EXPR:
2955       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2956             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2957             || typecode == VECTOR_TYPE))
2958         {
2959           error_at (location, "wrong type argument to unary minus");
2960           return error_mark_node;
2961         }
2962       else if (!noconvert)
2963         arg = default_conversion (arg);
2964       break;
2965
2966     case BIT_NOT_EXPR:
2967       /* ~ works on integer types and non float vectors. */
2968       if (typecode == INTEGER_TYPE
2969           || (typecode == VECTOR_TYPE
2970               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2971         {
2972           if (!noconvert)
2973             arg = default_conversion (arg);
2974         }
2975       else if (typecode == COMPLEX_TYPE)
2976         {
2977           code = CONJ_EXPR;
2978           pedwarn (location, OPT_pedantic,
2979                    "ISO C does not support %<~%> for complex conjugation");
2980           if (!noconvert)
2981             arg = default_conversion (arg);
2982         }
2983       else
2984         {
2985           error_at (location, "wrong type argument to bit-complement");
2986           return error_mark_node;
2987         }
2988       break;
2989
2990     case ABS_EXPR:
2991       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2992         {
2993           error_at (location, "wrong type argument to abs");
2994           return error_mark_node;
2995         }
2996       else if (!noconvert)
2997         arg = default_conversion (arg);
2998       break;
2999
3000     case CONJ_EXPR:
3001       /* Conjugating a real value is a no-op, but allow it anyway.  */
3002       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3003             || typecode == COMPLEX_TYPE))
3004         {
3005           error_at (location, "wrong type argument to conjugation");
3006           return error_mark_node;
3007         }
3008       else if (!noconvert)
3009         arg = default_conversion (arg);
3010       break;
3011
3012     case TRUTH_NOT_EXPR:
3013       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3014           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3015           && typecode != COMPLEX_TYPE)
3016         {
3017           error_at (location,
3018                     "wrong type argument to unary exclamation mark");
3019           return error_mark_node;
3020         }
3021       arg = c_objc_common_truthvalue_conversion (location, arg);
3022       ret = invert_truthvalue (arg);
3023       goto return_build_unary_op;
3024
3025     case REALPART_EXPR:
3026       if (TREE_CODE (arg) == COMPLEX_CST)
3027         ret = TREE_REALPART (arg);
3028       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3029         ret = fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3030       else
3031         ret = arg;
3032       goto return_build_unary_op;
3033
3034     case IMAGPART_EXPR:
3035       if (TREE_CODE (arg) == COMPLEX_CST)
3036         ret = TREE_IMAGPART (arg);
3037       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3038         ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3039       else
3040         ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
3041       goto return_build_unary_op;
3042
3043     case PREINCREMENT_EXPR:
3044     case POSTINCREMENT_EXPR:
3045     case PREDECREMENT_EXPR:
3046     case POSTDECREMENT_EXPR:
3047
3048       /* Increment or decrement the real part of the value,
3049          and don't change the imaginary part.  */
3050       if (typecode == COMPLEX_TYPE)
3051         {
3052           tree real, imag;
3053
3054           pedwarn (location, OPT_pedantic,
3055                    "ISO C does not support %<++%> and %<--%> on complex types");
3056
3057           arg = stabilize_reference (arg);
3058           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3059           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3060           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3061           if (real == error_mark_node || imag == error_mark_node)
3062             return error_mark_node;
3063           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3064                         real, imag);
3065           goto return_build_unary_op;
3066         }
3067
3068       /* Report invalid types.  */
3069
3070       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3071           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3072         {
3073           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3074             error_at (location, "wrong type argument to increment");
3075           else
3076             error_at (location, "wrong type argument to decrement");
3077
3078           return error_mark_node;
3079         }
3080
3081       {
3082         tree inc;
3083
3084         argtype = TREE_TYPE (arg);
3085
3086         /* Compute the increment.  */
3087
3088         if (typecode == POINTER_TYPE)
3089           {
3090             /* If pointer target is an undefined struct,
3091                we just cannot know how to do the arithmetic.  */
3092             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3093               {
3094                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3095                   error_at (location,
3096                             "increment of pointer to unknown structure");
3097                 else
3098                   error_at (location,
3099                             "decrement of pointer to unknown structure");
3100               }
3101             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3102                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3103               {
3104                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3105                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3106                            "wrong type argument to increment");
3107                 else
3108                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3109                            "wrong type argument to decrement");
3110               }
3111
3112             inc = c_size_in_bytes (TREE_TYPE (argtype));
3113             inc = fold_convert (sizetype, inc);
3114           }
3115         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3116           {
3117             /* For signed fract types, we invert ++ to -- or
3118                -- to ++, and change inc from 1 to -1, because
3119                it is not possible to represent 1 in signed fract constants.
3120                For unsigned fract types, the result always overflows and
3121                we get an undefined (original) or the maximum value.  */
3122             if (code == PREINCREMENT_EXPR)
3123               code = PREDECREMENT_EXPR;
3124             else if (code == PREDECREMENT_EXPR)
3125               code = PREINCREMENT_EXPR;
3126             else if (code == POSTINCREMENT_EXPR)
3127               code = POSTDECREMENT_EXPR;
3128             else /* code == POSTDECREMENT_EXPR  */
3129               code = POSTINCREMENT_EXPR;
3130
3131             inc = integer_minus_one_node;
3132             inc = convert (argtype, inc);
3133           }
3134         else
3135           {
3136             inc = integer_one_node;
3137             inc = convert (argtype, inc);
3138           }
3139
3140         /* Complain about anything else that is not a true lvalue.  */
3141         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3142                                     || code == POSTINCREMENT_EXPR)
3143                                    ? lv_increment
3144                                    : lv_decrement)))
3145           return error_mark_node;
3146
3147         /* Report a read-only lvalue.  */
3148         if (TREE_READONLY (arg))
3149           {
3150             readonly_error (arg,
3151                             ((code == PREINCREMENT_EXPR
3152                               || code == POSTINCREMENT_EXPR)
3153                              ? lv_increment : lv_decrement));
3154             return error_mark_node;
3155           }
3156
3157         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3158           val = boolean_increment (code, arg);
3159         else
3160           val = build2 (code, TREE_TYPE (arg), arg, inc);
3161         TREE_SIDE_EFFECTS (val) = 1;
3162         if (TREE_CODE (val) != code)
3163           TREE_NO_WARNING (val) = 1;
3164         ret = val;
3165         goto return_build_unary_op;
3166       }
3167
3168     case ADDR_EXPR:
3169       /* Note that this operation never does default_conversion.  */
3170
3171       /* Let &* cancel out to simplify resulting code.  */
3172       if (TREE_CODE (arg) == INDIRECT_REF)
3173         {
3174           /* Don't let this be an lvalue.  */
3175           if (lvalue_p (TREE_OPERAND (arg, 0)))
3176             return non_lvalue (TREE_OPERAND (arg, 0));
3177           ret = TREE_OPERAND (arg, 0);
3178           goto return_build_unary_op;
3179         }
3180
3181       /* For &x[y], return x+y */
3182       if (TREE_CODE (arg) == ARRAY_REF)
3183         {
3184           tree op0 = TREE_OPERAND (arg, 0);
3185           if (!c_mark_addressable (op0))
3186             return error_mark_node;
3187           return build_binary_op (location, PLUS_EXPR,
3188                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3189                                    ? array_to_pointer_conversion (op0)
3190                                    : op0),
3191                                   TREE_OPERAND (arg, 1), 1);
3192         }
3193
3194       /* Anything not already handled and not a true memory reference
3195          or a non-lvalue array is an error.  */
3196       else if (typecode != FUNCTION_TYPE && !flag
3197                && !lvalue_or_else (arg, lv_addressof))
3198         return error_mark_node;
3199
3200       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3201       argtype = TREE_TYPE (arg);
3202
3203       /* If the lvalue is const or volatile, merge that into the type
3204          to which the address will point.  Note that you can't get a
3205          restricted pointer by taking the address of something, so we
3206          only have to deal with `const' and `volatile' here.  */
3207       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3208           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3209           argtype = c_build_type_variant (argtype,
3210                                           TREE_READONLY (arg),
3211                                           TREE_THIS_VOLATILE (arg));
3212
3213       if (!c_mark_addressable (arg))
3214         return error_mark_node;
3215
3216       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3217                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3218
3219       argtype = build_pointer_type (argtype);
3220
3221       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3222          when we have proper support for integer constant expressions.  */
3223       val = get_base_address (arg);
3224       if (val && TREE_CODE (val) == INDIRECT_REF
3225           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3226         {
3227           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3228
3229           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3230           ret = fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3231           goto return_build_unary_op;
3232         }
3233
3234       val = build1 (ADDR_EXPR, argtype, arg);
3235
3236       ret = val;
3237       goto return_build_unary_op;
3238
3239     default:
3240       gcc_unreachable ();
3241     }
3242
3243   if (argtype == 0)
3244     argtype = TREE_TYPE (arg);
3245   ret = require_constant_value ? fold_build1_initializer (code, argtype, arg)
3246                                : fold_build1 (code, argtype, arg);
3247  return_build_unary_op:
3248   gcc_assert (ret != error_mark_node);
3249   protected_set_expr_location (ret, location);
3250   return ret;
3251 }
3252
3253 /* Return nonzero if REF is an lvalue valid for this language.
3254    Lvalues can be assigned, unless their type has TYPE_READONLY.
3255    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3256
3257 static int
3258 lvalue_p (const_tree ref)
3259 {
3260   const enum tree_code code = TREE_CODE (ref);
3261
3262   switch (code)
3263     {
3264     case REALPART_EXPR:
3265     case IMAGPART_EXPR:
3266     case COMPONENT_REF:
3267       return lvalue_p (TREE_OPERAND (ref, 0));
3268
3269     case COMPOUND_LITERAL_EXPR:
3270     case STRING_CST:
3271       return 1;
3272
3273     case INDIRECT_REF:
3274     case ARRAY_REF:
3275     case VAR_DECL:
3276     case PARM_DECL:
3277     case RESULT_DECL:
3278     case ERROR_MARK:
3279       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3280               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3281
3282     case BIND_EXPR:
3283       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3284
3285     default:
3286       return 0;
3287     }
3288 }
3289 \f
3290 /* Give an error for storing in something that is 'const'.  */
3291
3292 static void
3293 readonly_error (tree arg, enum lvalue_use use)
3294 {
3295   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3296               || use == lv_asm);
3297   /* Using this macro rather than (for example) arrays of messages
3298      ensures that all the format strings are checked at compile
3299      time.  */
3300 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3301                                    : (use == lv_increment ? (I)         \
3302                                    : (use == lv_decrement ? (D) : (AS))))
3303   if (TREE_CODE (arg) == COMPONENT_REF)
3304     {
3305       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3306         readonly_error (TREE_OPERAND (arg, 0), use);
3307       else
3308         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3309                              G_("increment of read-only member %qD"),
3310                              G_("decrement of read-only member %qD"),
3311                              G_("read-only member %qD used as %<asm%> output")),
3312                TREE_OPERAND (arg, 1));
3313     }
3314   else if (TREE_CODE (arg) == VAR_DECL)
3315     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3316                          G_("increment of read-only variable %qD"),
3317                          G_("decrement of read-only variable %qD"),
3318                          G_("read-only variable %qD used as %<asm%> output")),
3319            arg);
3320   else
3321     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3322                          G_("increment of read-only location %qE"),
3323                          G_("decrement of read-only location %qE"),
3324                          G_("read-only location %qE used as %<asm%> output")),
3325            arg);
3326 }
3327
3328
3329 /* Return nonzero if REF is an lvalue valid for this language;
3330    otherwise, print an error message and return zero.  USE says
3331    how the lvalue is being used and so selects the error message.  */
3332
3333 static int
3334 lvalue_or_else (const_tree ref, enum lvalue_use use)
3335 {
3336   int win = lvalue_p (ref);
3337
3338   if (!win)
3339     lvalue_error (use);
3340
3341   return win;
3342 }
3343 \f
3344 /* Mark EXP saying that we need to be able to take the
3345    address of it; it should not be allocated in a register.
3346    Returns true if successful.  */
3347
3348 bool
3349 c_mark_addressable (tree exp)
3350 {
3351   tree x = exp;
3352
3353   while (1)
3354     switch (TREE_CODE (x))
3355       {
3356       case COMPONENT_REF:
3357         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3358           {
3359             error
3360               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3361             return false;
3362           }
3363
3364         /* ... fall through ...  */
3365
3366       case ADDR_EXPR:
3367       case ARRAY_REF:
3368       case REALPART_EXPR:
3369       case IMAGPART_EXPR:
3370         x = TREE_OPERAND (x, 0);
3371         break;
3372
3373       case COMPOUND_LITERAL_EXPR:
3374       case CONSTRUCTOR:
3375         TREE_ADDRESSABLE (x) = 1;
3376         return true;
3377
3378       case VAR_DECL:
3379       case CONST_DECL:
3380       case PARM_DECL:
3381       case RESULT_DECL:
3382         if (C_DECL_REGISTER (x)
3383             && DECL_NONLOCAL (x))
3384           {
3385             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3386               {
3387                 error
3388                   ("global register variable %qD used in nested function", x);
3389                 return false;
3390               }
3391             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3392           }
3393         else if (C_DECL_REGISTER (x))
3394           {
3395             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3396               error ("address of global register variable %qD requested", x);
3397             else
3398               error ("address of register variable %qD requested", x);
3399             return false;
3400           }
3401
3402         /* drops in */
3403       case FUNCTION_DECL:
3404         TREE_ADDRESSABLE (x) = 1;
3405         /* drops out */
3406       default:
3407         return true;
3408     }
3409 }
3410 \f
3411 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3412
3413 tree
3414 build_conditional_expr (tree ifexp, tree op1, tree op2)
3415 {
3416   tree type1;
3417   tree type2;
3418   enum tree_code code1;
3419   enum tree_code code2;
3420   tree result_type = NULL;
3421   tree orig_op1 = op1, orig_op2 = op2;
3422
3423   /* Promote both alternatives.  */
3424
3425   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3426     op1 = default_conversion (op1);
3427   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3428     op2 = default_conversion (op2);
3429
3430   if (TREE_CODE (ifexp) == ERROR_MARK
3431       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3432       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3433     return error_mark_node;
3434
3435   type1 = TREE_TYPE (op1);
3436   code1 = TREE_CODE (type1);
3437   type2 = TREE_TYPE (op2);
3438   code2 = TREE_CODE (type2);
3439
3440   /* C90 does not permit non-lvalue arrays in conditional expressions.
3441      In C99 they will be pointers by now.  */
3442   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3443     {
3444       error ("non-lvalue array in conditional expression");
3445       return error_mark_node;
3446     }
3447
3448   /* Quickly detect the usual case where op1 and op2 have the same type
3449      after promotion.  */
3450   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3451     {
3452       if (type1 == type2)
3453         result_type = type1;
3454       else
3455         result_type = TYPE_MAIN_VARIANT (type1);
3456     }
3457   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3458             || code1 == COMPLEX_TYPE)
3459            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3460                || code2 == COMPLEX_TYPE))
3461     {
3462       result_type = c_common_type (type1, type2);
3463
3464       /* If -Wsign-compare, warn here if type1 and type2 have
3465          different signedness.  We'll promote the signed to unsigned
3466          and later code won't know it used to be different.
3467          Do this check on the original types, so that explicit casts
3468          will be considered, but default promotions won't.  */
3469       if (warn_sign_compare && !skip_evaluation)
3470         {
3471           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3472           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3473
3474           if (unsigned_op1 ^ unsigned_op2)
3475             {
3476               bool ovf;
3477
3478               /* Do not warn if the result type is signed, since the
3479                  signed type will only be chosen if it can represent
3480                  all the values of the unsigned type.  */
3481               if (!TYPE_UNSIGNED (result_type))
3482                 /* OK */;
3483               /* Do not warn if the signed quantity is an unsuffixed
3484                  integer literal (or some static constant expression
3485                  involving such literals) and it is non-negative.  */
3486               else if ((unsigned_op2
3487                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3488                        || (unsigned_op1
3489                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3490                 /* OK */;
3491               else
3492                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3493             }
3494         }
3495     }
3496   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3497     {
3498       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3499         pedwarn (input_location, OPT_pedantic,
3500                  "ISO C forbids conditional expr with only one void side");
3501       result_type = void_type_node;
3502     }
3503   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3504     {
3505       if (comp_target_types (type1, type2))
3506         result_type = common_pointer_type (type1, type2);
3507       else if (null_pointer_constant_p (orig_op1))
3508         result_type = qualify_type (type2, type1);
3509       else if (null_pointer_constant_p (orig_op2))
3510         result_type = qualify_type (type1, type2);
3511       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3512         {
3513           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3514             pedwarn (input_location, OPT_pedantic,
3515                      "ISO C forbids conditional expr between "
3516                      "%<void *%> and function pointer");
3517           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3518                                                           TREE_TYPE (type2)));
3519         }
3520       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3521         {
3522           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3523             pedwarn (input_location, OPT_pedantic,
3524                      "ISO C forbids conditional expr between "
3525                      "%<void *%> and function pointer");
3526           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3527                                                           TREE_TYPE (type1)));
3528         }
3529       else
3530         {
3531           pedwarn (input_location, 0,
3532                    "pointer type mismatch in conditional expression");
3533           result_type = build_pointer_type (void_type_node);
3534         }
3535     }
3536   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3537     {
3538       if (!null_pointer_constant_p (orig_op2))
3539         pedwarn (input_location, 0,
3540                  "pointer/integer type mismatch in conditional expression");
3541       else
3542         {
3543           op2 = null_pointer_node;
3544         }
3545       result_type = type1;
3546     }
3547   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3548     {
3549       if (!null_pointer_constant_p (orig_op1))
3550         pedwarn (input_location, 0,
3551                  "pointer/integer type mismatch in conditional expression");
3552       else
3553         {
3554           op1 = null_pointer_node;
3555         }
3556       result_type = type2;
3557     }
3558
3559   if (!result_type)
3560     {
3561       if (flag_cond_mismatch)
3562         result_type = void_type_node;
3563       else
3564         {
3565           error ("type mismatch in conditional expression");
3566           return error_mark_node;
3567         }
3568     }
3569
3570   /* Merge const and volatile flags of the incoming types.  */
3571   result_type
3572     = build_type_variant (result_type,
3573                           TREE_READONLY (op1) || TREE_READONLY (op2),
3574                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3575
3576   if (result_type != TREE_TYPE (op1))
3577     op1 = convert_and_check (result_type, op1);
3578   if (result_type != TREE_TYPE (op2))
3579     op2 = convert_and_check (result_type, op2);
3580
3581   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3582 }
3583 \f
3584 /* Return a compound expression that performs two expressions and
3585    returns the value of the second of them.  */
3586
3587 tree
3588 build_compound_expr (tree expr1, tree expr2)
3589 {
3590   if (!TREE_SIDE_EFFECTS (expr1))
3591     {
3592       /* The left-hand operand of a comma expression is like an expression
3593          statement: with -Wunused, we should warn if it doesn't have
3594          any side-effects, unless it was explicitly cast to (void).  */
3595       if (warn_unused_value)
3596         {
3597           if (VOID_TYPE_P (TREE_TYPE (expr1))
3598               && CONVERT_EXPR_P (expr1))
3599             ; /* (void) a, b */
3600           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3601                    && TREE_CODE (expr1) == COMPOUND_EXPR
3602                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3603             ; /* (void) a, (void) b, c */
3604           else
3605             warning (OPT_Wunused_value,
3606                      "left-hand operand of comma expression has no effect");
3607         }
3608     }
3609
3610   /* With -Wunused, we should also warn if the left-hand operand does have
3611      side-effects, but computes a value which is not used.  For example, in
3612      `foo() + bar(), baz()' the result of the `+' operator is not used,
3613      so we should issue a warning.  */
3614   else if (warn_unused_value)
3615     warn_if_unused_value (expr1, input_location);
3616
3617   if (expr2 == error_mark_node)
3618     return error_mark_node;
3619
3620   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3621 }
3622
3623 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3624
3625 tree
3626 build_c_cast (tree type, tree expr)
3627 {
3628   tree value = expr;
3629
3630   if (type == error_mark_node || expr == error_mark_node)
3631     return error_mark_node;
3632
3633   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3634      only in <protocol> qualifications.  But when constructing cast expressions,
3635      the protocols do matter and must be kept around.  */
3636   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3637     return build1 (NOP_EXPR, type, expr);
3638
3639   type = TYPE_MAIN_VARIANT (type);
3640
3641   if (TREE_CODE (type) == ARRAY_TYPE)
3642     {
3643       error ("cast specifies array type");
3644       return error_mark_node;
3645     }
3646
3647   if (TREE_CODE (type) == FUNCTION_TYPE)
3648     {
3649       error ("cast specifies function type");
3650       return error_mark_node;
3651     }
3652
3653   if (!VOID_TYPE_P (type))
3654     {
3655       value = require_complete_type (value);
3656       if (value == error_mark_node)
3657         return error_mark_node;
3658     }
3659
3660   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3661     {
3662       if (TREE_CODE (type) == RECORD_TYPE
3663           || TREE_CODE (type) == UNION_TYPE)
3664         pedwarn (input_location, OPT_pedantic,
3665                  "ISO C forbids casting nonscalar to the same type");
3666     }
3667   else if (TREE_CODE (type) == UNION_TYPE)
3668     {
3669       tree field;
3670
3671       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3672         if (TREE_TYPE (field) != error_mark_node
3673             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3674                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3675           break;
3676
3677       if (field)
3678         {
3679           tree t;
3680
3681           pedwarn (input_location, OPT_pedantic,
3682                    "ISO C forbids casts to union type");
3683           t = digest_init (type,
3684                            build_constructor_single (type, field, value),
3685                            true, 0);
3686           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3687           return t;
3688         }
3689       error ("cast to union type from type not present in union");
3690       return error_mark_node;
3691     }
3692   else
3693     {
3694       tree otype, ovalue;
3695
3696       if (type == void_type_node)
3697         return build1 (CONVERT_EXPR, type, value);
3698
3699       otype = TREE_TYPE (value);
3700
3701       /* Optionally warn about potentially worrisome casts.  */
3702
3703       if (warn_cast_qual
3704           && TREE_CODE (type) == POINTER_TYPE
3705           && TREE_CODE (otype) == POINTER_TYPE)
3706         {
3707           tree in_type = type;
3708           tree in_otype = otype;
3709           int added = 0;
3710           int discarded = 0;
3711
3712           /* Check that the qualifiers on IN_TYPE are a superset of
3713              the qualifiers of IN_OTYPE.  The outermost level of
3714              POINTER_TYPE nodes is uninteresting and we stop as soon
3715              as we hit a non-POINTER_TYPE node on either type.  */
3716           do
3717             {
3718               in_otype = TREE_TYPE (in_otype);
3719               in_type = TREE_TYPE (in_type);
3720
3721               /* GNU C allows cv-qualified function types.  'const'
3722                  means the function is very pure, 'volatile' means it
3723                  can't return.  We need to warn when such qualifiers
3724                  are added, not when they're taken away.  */
3725               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3726                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3727                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3728               else
3729                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3730             }
3731           while (TREE_CODE (in_type) == POINTER_TYPE
3732                  && TREE_CODE (in_otype) == POINTER_TYPE);
3733
3734           if (added)
3735             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3736
3737           if (discarded)
3738             /* There are qualifiers present in IN_OTYPE that are not
3739                present in IN_TYPE.  */
3740             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3741         }
3742
3743       /* Warn about possible alignment problems.  */
3744       if (STRICT_ALIGNMENT
3745           && TREE_CODE (type) == POINTER_TYPE
3746           && TREE_CODE (otype) == POINTER_TYPE
3747           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3748           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3749           /* Don't warn about opaque types, where the actual alignment
3750              restriction is unknown.  */
3751           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3752                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3753                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3754           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3755         warning (OPT_Wcast_align,
3756                  "cast increases required alignment of target type");
3757
3758       if (TREE_CODE (type) == INTEGER_TYPE
3759           && TREE_CODE (otype) == POINTER_TYPE
3760           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3761       /* Unlike conversion of integers to pointers, where the
3762          warning is disabled for converting constants because
3763          of cases such as SIG_*, warn about converting constant
3764          pointers to integers. In some cases it may cause unwanted
3765          sign extension, and a warning is appropriate.  */
3766         warning (OPT_Wpointer_to_int_cast,
3767                  "cast from pointer to integer of different size");
3768
3769       if (TREE_CODE (value) == CALL_EXPR
3770           && TREE_CODE (type) != TREE_CODE (otype))
3771         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3772                  "to non-matching type %qT", otype, type);
3773
3774       if (TREE_CODE (type) == POINTER_TYPE
3775           && TREE_CODE (otype) == INTEGER_TYPE
3776           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3777           /* Don't warn about converting any constant.  */
3778           && !TREE_CONSTANT (value))
3779         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3780                  "of different size");
3781
3782       if (warn_strict_aliasing <= 2)
3783         strict_aliasing_warning (otype, type, expr);
3784
3785       /* If pedantic, warn for conversions between function and object
3786          pointer types, except for converting a null pointer constant
3787          to function pointer type.  */
3788       if (pedantic
3789           && TREE_CODE (type) == POINTER_TYPE
3790           && TREE_CODE (otype) == POINTER_TYPE
3791           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3792           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3793         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3794                  "conversion of function pointer to object pointer type");
3795
3796       if (pedantic
3797           && TREE_CODE (type) == POINTER_TYPE
3798           && TREE_CODE (otype) == POINTER_TYPE
3799           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3800           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3801           && !null_pointer_constant_p (value))
3802         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3803                  "conversion of object pointer to function pointer type");
3804
3805       ovalue = value;
3806       value = convert (type, value);
3807
3808       /* Ignore any integer overflow caused by the cast.  */
3809       if (TREE_CODE (value) == INTEGER_CST)
3810         {
3811           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3812             {
3813               if (!TREE_OVERFLOW (value))
3814                 {
3815                   /* Avoid clobbering a shared constant.  */
3816                   value = copy_node (value);
3817                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3818                 }
3819             }
3820           else if (TREE_OVERFLOW (value))
3821             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3822             value = build_int_cst_wide (TREE_TYPE (value),
3823                                         TREE_INT_CST_LOW (value),
3824                                         TREE_INT_CST_HIGH (value));
3825         }
3826     }
3827
3828   /* Don't let a cast be an lvalue.  */
3829   if (value == expr)
3830     value = non_lvalue (value);
3831
3832   return value;
3833 }
3834
3835 /* Interpret a cast of expression EXPR to type TYPE.  */
3836 tree
3837 c_cast_expr (struct c_type_name *type_name, tree expr)
3838 {
3839   tree type;
3840   int saved_wsp = warn_strict_prototypes;
3841
3842   /* This avoids warnings about unprototyped casts on
3843      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3844   if (TREE_CODE (expr) == INTEGER_CST)
3845     warn_strict_prototypes = 0;
3846   type = groktypename (type_name);
3847   warn_strict_prototypes = saved_wsp;
3848
3849   return build_c_cast (type, expr);
3850 }
3851 \f
3852 /* Build an assignment expression of lvalue LHS from value RHS.
3853    MODIFYCODE is the code for a binary operator that we use
3854    to combine the old value of LHS with RHS to get the new value.
3855    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
3856
3857    LOCATION is the location of the MODIFYCODE operator.  */
3858
3859 tree
3860 build_modify_expr (location_t location,
3861                    tree lhs, enum tree_code modifycode, tree rhs)
3862 {
3863   tree result;
3864   tree newrhs;
3865   tree lhstype = TREE_TYPE (lhs);
3866   tree olhstype = lhstype;
3867
3868   /* Types that aren't fully specified cannot be used in assignments.  */
3869   lhs = require_complete_type (lhs);
3870
3871   /* Avoid duplicate error messages from operands that had errors.  */
3872   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3873     return error_mark_node;
3874
3875   if (!lvalue_or_else (lhs, lv_assign))
3876     return error_mark_node;
3877
3878   STRIP_TYPE_NOPS (rhs);
3879
3880   newrhs = rhs;
3881
3882   /* If a binary op has been requested, combine the old LHS value with the RHS
3883      producing the value we should actually store into the LHS.  */
3884
3885   if (modifycode != NOP_EXPR)
3886     {
3887       lhs = stabilize_reference (lhs);
3888       newrhs = build_binary_op (location,
3889                                 modifycode, lhs, rhs, 1);
3890     }
3891
3892   /* Give an error for storing in something that is 'const'.  */
3893
3894   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3895       || ((TREE_CODE (lhstype) == RECORD_TYPE
3896            || TREE_CODE (lhstype) == UNION_TYPE)
3897           && C_TYPE_FIELDS_READONLY (lhstype)))
3898     {
3899       readonly_error (lhs, lv_assign);
3900       return error_mark_node;
3901     }
3902
3903   /* If storing into a structure or union member,
3904      it has probably been given type `int'.
3905      Compute the type that would go with
3906      the actual amount of storage the member occupies.  */
3907
3908   if (TREE_CODE (lhs) == COMPONENT_REF
3909       && (TREE_CODE (lhstype) == INTEGER_TYPE
3910           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3911           || TREE_CODE (lhstype) == REAL_TYPE
3912           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3913     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3914
3915   /* If storing in a field that is in actuality a short or narrower than one,
3916      we must store in the field in its actual type.  */
3917
3918   if (lhstype != TREE_TYPE (lhs))
3919     {
3920       lhs = copy_node (lhs);
3921       TREE_TYPE (lhs) = lhstype;
3922     }
3923
3924   /* Convert new value to destination type.  */
3925
3926   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3927                                    NULL_TREE, NULL_TREE, 0);
3928   if (TREE_CODE (newrhs) == ERROR_MARK)
3929     return error_mark_node;
3930
3931   /* Emit ObjC write barrier, if necessary.  */
3932   if (c_dialect_objc () && flag_objc_gc)
3933     {
3934       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3935       if (result)
3936         {
3937           protected_set_expr_location (result, location);
3938           return result;
3939         }
3940     }
3941
3942   /* Scan operands.  */
3943
3944   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3945   TREE_SIDE_EFFECTS (result) = 1;
3946   protected_set_expr_location (result, location);
3947
3948   /* If we got the LHS in a different type for storing in,
3949      convert the result back to the nominal type of LHS
3950      so that the value we return always has the same type
3951      as the LHS argument.  */
3952
3953   if (olhstype == TREE_TYPE (result))
3954     return result;
3955
3956   result = convert_for_assignment (olhstype, result, ic_assign,
3957                                    NULL_TREE, NULL_TREE, 0);
3958   protected_set_expr_location (result, location);
3959   return result;
3960 }
3961 \f
3962 /* Convert value RHS to type TYPE as preparation for an assignment
3963    to an lvalue of type TYPE.
3964    The real work of conversion is done by `convert'.
3965    The purpose of this function is to generate error messages
3966    for assignments that are not allowed in C.
3967    ERRTYPE says whether it is argument passing, assignment,
3968    initialization or return.
3969
3970    FUNCTION is a tree for the function being called.
3971    PARMNUM is the number of the argument, for printing in error messages.  */
3972
3973 static tree
3974 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3975                         tree fundecl, tree function, int parmnum)
3976 {
3977   enum tree_code codel = TREE_CODE (type);
3978   tree rhstype;
3979   enum tree_code coder;
3980   tree rname = NULL_TREE;
3981   bool objc_ok = false;
3982
3983   if (errtype == ic_argpass)
3984     {
3985       tree selector;
3986       /* Change pointer to function to the function itself for
3987          diagnostics.  */
3988       if (TREE_CODE (function) == ADDR_EXPR
3989           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3990         function = TREE_OPERAND (function, 0);
3991
3992       /* Handle an ObjC selector specially for diagnostics.  */
3993       selector = objc_message_selector ();
3994       rname = function;
3995       if (selector && parmnum > 2)
3996         {
3997           rname = selector;
3998           parmnum -= 2;
3999         }
4000     }
4001
4002   /* This macro is used to emit diagnostics to ensure that all format
4003      strings are complete sentences, visible to gettext and checked at
4004      compile time.  */
4005 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4006   do {                                                                   \
4007     switch (errtype)                                                     \
4008       {                                                                  \
4009       case ic_argpass:                                                   \
4010         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4011           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4012                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4013                   "expected %qT but argument is of type %qT",            \
4014                   type, rhstype);                                        \
4015         break;                                                           \
4016       case ic_assign:                                                    \
4017         pedwarn (LOCATION, OPT, AS);                                     \
4018         break;                                                           \
4019       case ic_init:                                                      \
4020         pedwarn (LOCATION, OPT, IN);                                     \
4021         break;                                                           \
4022       case ic_return:                                                    \
4023         pedwarn (LOCATION, OPT, RE);                                     \
4024         break;                                                           \
4025       default:                                                           \
4026         gcc_unreachable ();                                              \
4027       }                                                                  \
4028   } while (0)
4029
4030   STRIP_TYPE_NOPS (rhs);
4031
4032   if (optimize && TREE_CODE (rhs) == VAR_DECL
4033            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
4034     rhs = decl_constant_value_for_broken_optimization (rhs);
4035
4036   rhstype = TREE_TYPE (rhs);
4037   coder = TREE_CODE (rhstype);
4038
4039   if (coder == ERROR_MARK)
4040     return error_mark_node;
4041
4042   if (c_dialect_objc ())
4043     {
4044       int parmno;
4045
4046       switch (errtype)
4047         {
4048         case ic_return:
4049           parmno = 0;
4050           break;
4051
4052         case ic_assign:
4053           parmno = -1;
4054           break;
4055
4056         case ic_init:
4057           parmno = -2;
4058           break;
4059
4060         default:
4061           parmno = parmnum;
4062           break;
4063         }
4064
4065       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4066     }
4067
4068   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4069     return rhs;
4070
4071   if (coder == VOID_TYPE)
4072     {
4073       /* Except for passing an argument to an unprototyped function,
4074          this is a constraint violation.  When passing an argument to
4075          an unprototyped function, it is compile-time undefined;
4076          making it a constraint in that case was rejected in
4077          DR#252.  */
4078       error ("void value not ignored as it ought to be");
4079       return error_mark_node;
4080     }
4081   rhs = require_complete_type (rhs);
4082   if (rhs == error_mark_node)
4083     return error_mark_node;
4084   /* A type converts to a reference to it.
4085      This code doesn't fully support references, it's just for the
4086      special case of va_start and va_copy.  */
4087   if (codel == REFERENCE_TYPE
4088       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4089     {
4090       if (!lvalue_p (rhs))
4091         {
4092           error ("cannot pass rvalue to reference parameter");
4093           return error_mark_node;
4094         }
4095       if (!c_mark_addressable (rhs))
4096         return error_mark_node;
4097       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4098
4099       /* We already know that these two types are compatible, but they
4100          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4101          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4102          likely to be va_list, a typedef to __builtin_va_list, which
4103          is different enough that it will cause problems later.  */
4104       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4105         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4106
4107       rhs = build1 (NOP_EXPR, type, rhs);
4108       return rhs;
4109     }
4110   /* Some types can interconvert without explicit casts.  */
4111   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4112            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4113     return convert (type, rhs);
4114   /* Arithmetic types all interconvert, and enum is treated like int.  */
4115   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4116             || codel == FIXED_POINT_TYPE
4117             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4118             || codel == BOOLEAN_TYPE)
4119            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4120                || coder == FIXED_POINT_TYPE
4121                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4122                || coder == BOOLEAN_TYPE))
4123     return convert_and_check (type, rhs);
4124
4125   /* Aggregates in different TUs might need conversion.  */
4126   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4127       && codel == coder
4128       && comptypes (type, rhstype))
4129     return convert_and_check (type, rhs);
4130
4131   /* Conversion to a transparent union from its member types.
4132      This applies only to function arguments.  */
4133   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4134       && errtype == ic_argpass)
4135     {
4136       tree memb, marginal_memb = NULL_TREE;
4137
4138       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4139         {
4140           tree memb_type = TREE_TYPE (memb);
4141
4142           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4143                          TYPE_MAIN_VARIANT (rhstype)))
4144             break;
4145
4146           if (TREE_CODE (memb_type) != POINTER_TYPE)
4147             continue;
4148
4149           if (coder == POINTER_TYPE)
4150             {
4151               tree ttl = TREE_TYPE (memb_type);
4152               tree ttr = TREE_TYPE (rhstype);
4153
4154               /* Any non-function converts to a [const][volatile] void *
4155                  and vice versa; otherwise, targets must be the same.
4156                  Meanwhile, the lhs target must have all the qualifiers of
4157                  the rhs.  */
4158               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4159                   || comp_target_types (memb_type, rhstype))
4160                 {
4161                   /* If this type won't generate any warnings, use it.  */
4162                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4163                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4164                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4165                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4166                              == TYPE_QUALS (ttr))
4167                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4168                              == TYPE_QUALS (ttl))))
4169                     break;
4170
4171                   /* Keep looking for a better type, but remember this one.  */
4172                   if (!marginal_memb)
4173                     marginal_memb = memb;
4174                 }
4175             }
4176
4177           /* Can convert integer zero to any pointer type.  */
4178           if (null_pointer_constant_p (rhs))
4179             {
4180               rhs = null_pointer_node;
4181               break;
4182             }
4183         }
4184
4185       if (memb || marginal_memb)
4186         {
4187           if (!memb)
4188             {
4189               /* We have only a marginally acceptable member type;
4190                  it needs a warning.  */
4191               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4192               tree ttr = TREE_TYPE (rhstype);
4193
4194               /* Const and volatile mean something different for function
4195                  types, so the usual warnings are not appropriate.  */
4196               if (TREE_CODE (ttr) == FUNCTION_TYPE
4197                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4198                 {
4199                   /* Because const and volatile on functions are
4200                      restrictions that say the function will not do
4201                      certain things, it is okay to use a const or volatile
4202                      function where an ordinary one is wanted, but not
4203                      vice-versa.  */
4204                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4205                     WARN_FOR_ASSIGNMENT (input_location, 0,
4206                                          G_("passing argument %d of %qE "
4207                                             "makes qualified function "
4208                                             "pointer from unqualified"),
4209                                          G_("assignment makes qualified "
4210                                             "function pointer from "
4211                                             "unqualified"),
4212                                          G_("initialization makes qualified "
4213                                             "function pointer from "
4214                                             "unqualified"),
4215                                          G_("return makes qualified function "
4216                                             "pointer from unqualified"));
4217                 }
4218               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4219                 WARN_FOR_ASSIGNMENT (input_location, 0,
4220                                      G_("passing argument %d of %qE discards "
4221                                         "qualifiers from pointer target type"),
4222                                      G_("assignment discards qualifiers "
4223                                         "from pointer target type"),
4224                                      G_("initialization discards qualifiers "
4225                                         "from pointer target type"),
4226                                      G_("return discards qualifiers from "
4227                                         "pointer target type"));
4228
4229               memb = marginal_memb;
4230             }
4231
4232           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4233             pedwarn (input_location, OPT_pedantic,
4234                      "ISO C prohibits argument conversion to union type");
4235
4236           rhs = fold_convert (TREE_TYPE (memb), rhs);
4237           return build_constructor_single (type, memb, rhs);
4238         }
4239     }
4240
4241   /* Conversions among pointers */
4242   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4243            && (coder == codel))
4244     {
4245       tree ttl = TREE_TYPE (type);
4246       tree ttr = TREE_TYPE (rhstype);
4247       tree mvl = ttl;
4248       tree mvr = ttr;
4249       bool is_opaque_pointer;
4250       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4251
4252       if (TREE_CODE (mvl) != ARRAY_TYPE)
4253         mvl = TYPE_MAIN_VARIANT (mvl);
4254       if (TREE_CODE (mvr) != ARRAY_TYPE)
4255         mvr = TYPE_MAIN_VARIANT (mvr);
4256       /* Opaque pointers are treated like void pointers.  */
4257       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4258
4259       /* C++ does not allow the implicit conversion void* -> T*.  However,
4260          for the purpose of reducing the number of false positives, we
4261          tolerate the special case of
4262
4263                 int *p = NULL;
4264
4265          where NULL is typically defined in C to be '(void *) 0'.  */
4266       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4267         warning (OPT_Wc___compat, "request for implicit conversion from "
4268                  "%qT to %qT not permitted in C++", rhstype, type);
4269
4270       /* Check if the right-hand side has a format attribute but the
4271          left-hand side doesn't.  */
4272       if (warn_missing_format_attribute
4273           && check_missing_format_attribute (type, rhstype))
4274         {
4275           switch (errtype)
4276           {
4277           case ic_argpass:
4278             warning (OPT_Wmissing_format_attribute,
4279                      "argument %d of %qE might be "
4280                      "a candidate for a format attribute",
4281                      parmnum, rname);
4282             break;
4283           case ic_assign:
4284             warning (OPT_Wmissing_format_attribute,
4285                      "assignment left-hand side might be "
4286                      "a candidate for a format attribute");
4287             break;
4288           case ic_init:
4289             warning (OPT_Wmissing_format_attribute,
4290                      "initialization left-hand side might be "
4291                      "a candidate for a format attribute");
4292             break;
4293           case ic_return:
4294             warning (OPT_Wmissing_format_attribute,
4295                      "return type might be "
4296                      "a candidate for a format attribute");
4297             break;
4298           default:
4299             gcc_unreachable ();
4300           }
4301         }
4302
4303       /* Any non-function converts to a [const][volatile] void *
4304          and vice versa; otherwise, targets must be the same.
4305          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4306       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4307           || (target_cmp = comp_target_types (type, rhstype))
4308           || is_opaque_pointer
4309           || (c_common_unsigned_type (mvl)
4310               == c_common_unsigned_type (mvr)))
4311         {
4312           if (pedantic
4313               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4314                   ||
4315                   (VOID_TYPE_P (ttr)
4316                    && !null_pointer_constant_p (rhs)
4317                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4318             WARN_FOR_ASSIGNMENT (input_location, OPT_pedantic,
4319                                  G_("ISO C forbids passing argument %d of "
4320                                     "%qE between function pointer "
4321                                     "and %<void *%>"),
4322                                  G_("ISO C forbids assignment between "
4323                                     "function pointer and %<void *%>"),
4324                                  G_("ISO C forbids initialization between "
4325                                     "function pointer and %<void *%>"),
4326                                  G_("ISO C forbids return between function "
4327                                     "pointer and %<void *%>"));
4328           /* Const and volatile mean something different for function types,
4329              so the usual warnings are not appropriate.  */
4330           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4331                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4332             {
4333               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4334                 {
4335                   /* Types differing only by the presence of the 'volatile'
4336                      qualifier are acceptable if the 'volatile' has been added
4337                      in by the Objective-C EH machinery.  */
4338                   if (!objc_type_quals_match (ttl, ttr))
4339                     WARN_FOR_ASSIGNMENT (input_location, 0,
4340                                          G_("passing argument %d of %qE discards "
4341                                             "qualifiers from pointer target type"),
4342                                          G_("assignment discards qualifiers "
4343                                             "from pointer target type"),
4344                                          G_("initialization discards qualifiers "
4345                                             "from pointer target type"),
4346                                          G_("return discards qualifiers from "
4347                                             "pointer target type"));
4348                 }
4349               /* If this is not a case of ignoring a mismatch in signedness,
4350                  no warning.  */
4351               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4352                        || target_cmp)
4353                 ;
4354               /* If there is a mismatch, do warn.  */
4355               else if (warn_pointer_sign)
4356                 WARN_FOR_ASSIGNMENT (input_location, OPT_Wpointer_sign,
4357                                      G_("pointer targets in passing argument "
4358                                         "%d of %qE differ in signedness"),
4359                                      G_("pointer targets in assignment "
4360                                         "differ in signedness"),
4361                                      G_("pointer targets in initialization "
4362                                         "differ in signedness"),
4363                                      G_("pointer targets in return differ "
4364                                         "in signedness"));
4365             }
4366           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4367                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4368             {
4369               /* Because const and volatile on functions are restrictions
4370                  that say the function will not do certain things,
4371                  it is okay to use a const or volatile function
4372                  where an ordinary one is wanted, but not vice-versa.  */
4373               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4374                 WARN_FOR_ASSIGNMENT (input_location, 0,
4375                                      G_("passing argument %d of %qE makes "
4376                                         "qualified function pointer "
4377                                         "from unqualified"),
4378                                      G_("assignment makes qualified function "
4379                                         "pointer from unqualified"),
4380                                      G_("initialization makes qualified "
4381                                         "function pointer from unqualified"),
4382                                      G_("return makes qualified function "
4383                                         "pointer from unqualified"));
4384             }
4385         }
4386       else
4387         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4388         if (!objc_ok)
4389           WARN_FOR_ASSIGNMENT (input_location, 0,
4390                                G_("passing argument %d of %qE from "
4391                                   "incompatible pointer type"),
4392                                G_("assignment from incompatible pointer type"),
4393                                G_("initialization from incompatible "
4394                                   "pointer type"),
4395                                G_("return from incompatible pointer type"));
4396
4397       return convert (type, rhs);
4398     }
4399   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4400     {
4401       /* ??? This should not be an error when inlining calls to
4402          unprototyped functions.  */
4403       error ("invalid use of non-lvalue array");
4404       return error_mark_node;
4405     }
4406   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4407     {
4408       /* An explicit constant 0 can convert to a pointer,
4409          or one that results from arithmetic, even including
4410          a cast to integer type.  */
4411       if (!null_pointer_constant_p (rhs))
4412         WARN_FOR_ASSIGNMENT (input_location, 0,
4413                              G_("passing argument %d of %qE makes "
4414                                 "pointer from integer without a cast"),
4415                              G_("assignment makes pointer from integer "
4416                                 "without a cast"),
4417                              G_("initialization makes pointer from "
4418                                 "integer without a cast"),
4419                              G_("return makes pointer from integer "
4420                                 "without a cast"));
4421
4422       return convert (type, rhs);
4423     }
4424   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4425     {
4426       WARN_FOR_ASSIGNMENT (input_location, 0,
4427                            G_("passing argument %d of %qE makes integer "
4428                               "from pointer without a cast"),
4429                            G_("assignment makes integer from pointer "
4430                               "without a cast"),
4431                            G_("initialization makes integer from pointer "
4432                               "without a cast"),
4433                            G_("return makes integer from pointer "
4434                               "without a cast"));
4435       return convert (type, rhs);
4436     }
4437   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4438     return convert (type, rhs);
4439
4440   switch (errtype)
4441     {
4442     case ic_argpass:
4443       error ("incompatible type for argument %d of %qE", parmnum, rname);
4444       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
4445               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
4446               "expected %qT but argument is of type %qT", type, rhstype);
4447       break;
4448     case ic_assign:
4449       error ("incompatible types when assigning to type %qT from type %qT",
4450              type, rhstype);
4451       break;
4452     case ic_init:
4453       error ("incompatible types when initializing type %qT using type %qT",
4454              type, rhstype);
4455       break;
4456     case ic_return:
4457       error ("incompatible types when returning type %qT but %qT was expected",
4458              rhstype, type);
4459       break;
4460     default:
4461       gcc_unreachable ();
4462     }
4463
4464   return error_mark_node;
4465 }
4466 \f
4467 /* If VALUE is a compound expr all of whose expressions are constant, then
4468    return its value.  Otherwise, return error_mark_node.
4469
4470    This is for handling COMPOUND_EXPRs as initializer elements
4471    which is allowed with a warning when -pedantic is specified.  */
4472
4473 static tree
4474 valid_compound_expr_initializer (tree value, tree endtype)
4475 {
4476   if (TREE_CODE (value) == COMPOUND_EXPR)
4477     {
4478       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4479           == error_mark_node)
4480         return error_mark_node;
4481       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4482                                               endtype);
4483     }
4484   else if (!initializer_constant_valid_p (value, endtype))
4485     return error_mark_node;
4486   else
4487     return value;
4488 }
4489 \f
4490 /* Perform appropriate conversions on the initial value of a variable,
4491    store it in the declaration DECL,
4492    and print any error messages that are appropriate.
4493    If the init is invalid, store an ERROR_MARK.  */
4494
4495 void
4496 store_init_value (tree decl, tree init)
4497 {
4498   tree value, type;
4499
4500   /* If variable's type was invalidly declared, just ignore it.  */
4501
4502   type = TREE_TYPE (decl);
4503   if (TREE_CODE (type) == ERROR_MARK)
4504     return;
4505
4506   /* Digest the specified initializer into an expression.  */
4507
4508   value = digest_init (type, init, true, TREE_STATIC (decl));
4509
4510   /* Store the expression if valid; else report error.  */
4511
4512   if (!in_system_header
4513       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4514     warning (OPT_Wtraditional, "traditional C rejects automatic "
4515              "aggregate initialization");
4516
4517   DECL_INITIAL (decl) = value;
4518
4519   /* ANSI wants warnings about out-of-range constant initializers.  */
4520   STRIP_TYPE_NOPS (value);
4521   if (TREE_STATIC (decl))
4522     constant_expression_warning (value);
4523
4524   /* Check if we need to set array size from compound literal size.  */
4525   if (TREE_CODE (type) == ARRAY_TYPE
4526       && TYPE_DOMAIN (type) == 0
4527       && value != error_mark_node)
4528     {
4529       tree inside_init = init;
4530
4531       STRIP_TYPE_NOPS (inside_init);
4532       inside_init = fold (inside_init);
4533
4534       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4535         {
4536           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4537
4538           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4539             {
4540               /* For int foo[] = (int [3]){1}; we need to set array size
4541                  now since later on array initializer will be just the
4542                  brace enclosed list of the compound literal.  */
4543               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4544               TREE_TYPE (decl) = type;
4545               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4546               layout_type (type);
4547               layout_decl (cldecl, 0);
4548             }
4549         }
4550     }
4551 }
4552 \f
4553 /* Methods for storing and printing names for error messages.  */
4554
4555 /* Implement a spelling stack that allows components of a name to be pushed
4556    and popped.  Each element on the stack is this structure.  */
4557
4558 struct spelling
4559 {
4560   int kind;
4561   union
4562     {
4563       unsigned HOST_WIDE_INT i;
4564       const char *s;
4565     } u;
4566 };
4567
4568 #define SPELLING_STRING 1
4569 #define SPELLING_MEMBER 2
4570 #define SPELLING_BOUNDS 3
4571
4572 static struct spelling *spelling;       /* Next stack element (unused).  */
4573 static struct spelling *spelling_base;  /* Spelling stack base.  */
4574 static int spelling_size;               /* Size of the spelling stack.  */
4575
4576 /* Macros to save and restore the spelling stack around push_... functions.
4577    Alternative to SAVE_SPELLING_STACK.  */
4578
4579 #define SPELLING_DEPTH() (spelling - spelling_base)
4580 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4581
4582 /* Push an element on the spelling stack with type KIND and assign VALUE
4583    to MEMBER.  */
4584
4585 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4586 {                                                                       \
4587   int depth = SPELLING_DEPTH ();                                        \
4588                                                                         \
4589   if (depth >= spelling_size)                                           \
4590     {                                                                   \
4591       spelling_size += 10;                                              \
4592       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4593                                   spelling_size);                       \
4594       RESTORE_SPELLING_DEPTH (depth);                                   \
4595     }                                                                   \
4596                                                                         \
4597   spelling->kind = (KIND);                                              \
4598   spelling->MEMBER = (VALUE);                                           \
4599   spelling++;                                                           \
4600 }
4601
4602 /* Push STRING on the stack.  Printed literally.  */
4603
4604 static void
4605 push_string (const char *string)
4606 {
4607   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4608 }
4609
4610 /* Push a member name on the stack.  Printed as '.' STRING.  */
4611
4612 static void
4613 push_member_name (tree decl)
4614 {
4615   const char *const string
4616     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4617   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4618 }
4619
4620 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4621
4622 static void
4623 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4624 {
4625   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4626 }
4627
4628 /* Compute the maximum size in bytes of the printed spelling.  */
4629
4630 static int
4631 spelling_length (void)
4632 {
4633   int size = 0;
4634   struct spelling *p;
4635
4636   for (p = spelling_base; p < spelling; p++)
4637     {
4638       if (p->kind == SPELLING_BOUNDS)
4639         size += 25;
4640       else
4641         size += strlen (p->u.s) + 1;
4642     }
4643
4644   return size;
4645 }
4646
4647 /* Print the spelling to BUFFER and return it.  */
4648
4649 static char *
4650 print_spelling (char *buffer)
4651 {
4652   char *d = buffer;
4653   struct spelling *p;
4654
4655   for (p = spelling_base; p < spelling; p++)
4656     if (p->kind == SPELLING_BOUNDS)
4657       {
4658         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4659         d += strlen (d);
4660       }
4661     else
4662       {
4663         const char *s;
4664         if (p->kind == SPELLING_MEMBER)
4665           *d++ = '.';
4666         for (s = p->u.s; (*d = *s++); d++)
4667           ;
4668       }
4669   *d++ = '\0';
4670   return buffer;
4671 }
4672
4673 /* Issue an error message for a bad initializer component.
4674    MSGID identifies the message.
4675    The component name is taken from the spelling stack.  */
4676
4677 void
4678 error_init (const char *msgid)
4679 {
4680   char *ofwhat;
4681
4682   error ("%s", _(msgid));
4683   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4684   if (*ofwhat)
4685     error ("(near initialization for %qs)", ofwhat);
4686 }
4687
4688 /* Issue a pedantic warning for a bad initializer component.  OPT is
4689    the option OPT_* (from options.h) controlling this warning or 0 if
4690    it is unconditionally given.  MSGID identifies the message.  The
4691    component name is taken from the spelling stack.  */
4692
4693 void
4694 pedwarn_init (location_t location, int opt, const char *msgid)
4695 {
4696   char *ofwhat;
4697
4698   pedwarn (location, opt, "%s", _(msgid));
4699   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4700   if (*ofwhat)
4701     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
4702 }
4703
4704 /* Issue a warning for a bad initializer component.
4705
4706    OPT is the OPT_W* value corresponding to the warning option that
4707    controls this warning.  MSGID identifies the message.  The
4708    component name is taken from the spelling stack.  */
4709
4710 static void
4711 warning_init (int opt, const char *msgid)
4712 {
4713   char *ofwhat;
4714
4715   warning (opt, "%s", _(msgid));
4716   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4717   if (*ofwhat)
4718     warning (opt, "(near initialization for %qs)", ofwhat);
4719 }
4720 \f
4721 /* If TYPE is an array type and EXPR is a parenthesized string
4722    constant, warn if pedantic that EXPR is being used to initialize an
4723    object of type TYPE.  */
4724
4725 void
4726 maybe_warn_string_init (tree type, struct c_expr expr)
4727 {
4728   if (pedantic
4729       && TREE_CODE (type) == ARRAY_TYPE
4730       && TREE_CODE (expr.value) == STRING_CST
4731       && expr.original_code != STRING_CST)
4732     pedwarn_init (input_location, OPT_pedantic,
4733                   "array initialized from parenthesized string constant");
4734 }
4735
4736 /* Digest the parser output INIT as an initializer for type TYPE.
4737    Return a C expression of type TYPE to represent the initial value.
4738
4739    If INIT is a string constant, STRICT_STRING is true if it is
4740    unparenthesized or we should not warn here for it being parenthesized.
4741    For other types of INIT, STRICT_STRING is not used.
4742
4743    REQUIRE_CONSTANT requests an error if non-constant initializers or
4744    elements are seen.  */
4745
4746 static tree
4747 digest_init (tree type, tree init, bool strict_string, int require_constant)
4748 {
4749   enum tree_code code = TREE_CODE (type);
4750   tree inside_init = init;
4751
4752   if (type == error_mark_node
4753       || !init
4754       || init == error_mark_node
4755       || TREE_TYPE (init) == error_mark_node)
4756     return error_mark_node;
4757
4758   STRIP_TYPE_NOPS (inside_init);
4759
4760   inside_init = fold (inside_init);
4761
4762   /* Initialization of an array of chars from a string constant
4763      optionally enclosed in braces.  */
4764
4765   if (code == ARRAY_TYPE && inside_init
4766       && TREE_CODE (inside_init) == STRING_CST)
4767     {
4768       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4769       /* Note that an array could be both an array of character type
4770          and an array of wchar_t if wchar_t is signed char or unsigned
4771          char.  */
4772       bool char_array = (typ1 == char_type_node
4773                          || typ1 == signed_char_type_node
4774                          || typ1 == unsigned_char_type_node);
4775       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4776       bool char16_array = !!comptypes (typ1, char16_type_node);
4777       bool char32_array = !!comptypes (typ1, char32_type_node);
4778
4779       if (char_array || wchar_array || char16_array || char32_array)
4780         {
4781           struct c_expr expr;
4782           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
4783           expr.value = inside_init;
4784           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4785           maybe_warn_string_init (type, expr);
4786
4787           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4788                          TYPE_MAIN_VARIANT (type)))
4789             return inside_init;
4790
4791           if (char_array)
4792             {
4793               if (typ2 != char_type_node)
4794                 {
4795                   error_init ("char-array initialized from wide string");
4796                   return error_mark_node;
4797                 }
4798             }
4799           else
4800             {
4801               if (typ2 == char_type_node)
4802                 {
4803                   error_init ("wide character array initialized from non-wide "
4804                               "string");
4805                   return error_mark_node;
4806                 }
4807               else if (!comptypes(typ1, typ2))
4808                 {
4809                   error_init ("wide character array initialized from "
4810                               "incompatible wide string");
4811                   return error_mark_node;
4812                 }
4813             }
4814
4815           TREE_TYPE (inside_init) = type;
4816           if (TYPE_DOMAIN (type) != 0
4817               && TYPE_SIZE (type) != 0
4818               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4819               /* Subtract the size of a single (possibly wide) character
4820                  because it's ok to ignore the terminating null char
4821                  that is counted in the length of the constant.  */
4822               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4823                                        TREE_STRING_LENGTH (inside_init)
4824                                        - (TYPE_PRECISION (typ1)
4825                                           / BITS_PER_UNIT)))
4826             pedwarn_init (input_location, 0,
4827                           "initializer-string for array of chars is too long");
4828
4829           return inside_init;
4830         }
4831       else if (INTEGRAL_TYPE_P (typ1))
4832         {
4833           error_init ("array of inappropriate type initialized "
4834                       "from string constant");
4835           return error_mark_node;
4836         }
4837     }
4838
4839   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4840      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4841      below and handle as a constructor.  */
4842   if (code == VECTOR_TYPE
4843       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4844       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4845       && TREE_CONSTANT (inside_init))
4846     {
4847       if (TREE_CODE (inside_init) == VECTOR_CST
4848           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4849                         TYPE_MAIN_VARIANT (type)))
4850         return inside_init;
4851
4852       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4853         {
4854           unsigned HOST_WIDE_INT ix;
4855           tree value;
4856           bool constant_p = true;
4857
4858           /* Iterate through elements and check if all constructor
4859              elements are *_CSTs.  */
4860           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4861             if (!CONSTANT_CLASS_P (value))
4862               {
4863                 constant_p = false;
4864                 break;
4865               }
4866
4867           if (constant_p)
4868             return build_vector_from_ctor (type,
4869                                            CONSTRUCTOR_ELTS (inside_init));
4870         }
4871     }
4872
4873   if (warn_sequence_point)
4874     verify_sequence_points (inside_init);
4875
4876   /* Any type can be initialized
4877      from an expression of the same type, optionally with braces.  */
4878
4879   if (inside_init && TREE_TYPE (inside_init) != 0
4880       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4881                      TYPE_MAIN_VARIANT (type))
4882           || (code == ARRAY_TYPE
4883               && comptypes (TREE_TYPE (inside_init), type))
4884           || (code == VECTOR_TYPE
4885               && comptypes (TREE_TYPE (inside_init), type))
4886           || (code == POINTER_TYPE
4887               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4888               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4889                             TREE_TYPE (type)))))
4890     {
4891       if (code == POINTER_TYPE)
4892         {
4893           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4894             {
4895               if (TREE_CODE (inside_init) == STRING_CST
4896                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4897                 inside_init = array_to_pointer_conversion (inside_init);
4898               else
4899                 {
4900                   error_init ("invalid use of non-lvalue array");
4901                   return error_mark_node;
4902                 }
4903             }
4904         }
4905
4906       if (code == VECTOR_TYPE)
4907         /* Although the types are compatible, we may require a
4908            conversion.  */
4909         inside_init = convert (type, inside_init);
4910
4911       if (require_constant
4912           && (code == VECTOR_TYPE || !flag_isoc99)
4913           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4914         {
4915           /* As an extension, allow initializing objects with static storage
4916              duration with compound literals (which are then treated just as
4917              the brace enclosed list they contain).  Also allow this for
4918              vectors, as we can only assign them with compound literals.  */
4919           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4920           inside_init = DECL_INITIAL (decl);
4921         }
4922
4923       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4924           && TREE_CODE (inside_init) != CONSTRUCTOR)
4925         {
4926           error_init ("array initialized from non-constant array expression");
4927           return error_mark_node;
4928         }
4929
4930       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4931         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4932
4933       /* Compound expressions can only occur here if -pedantic or
4934          -pedantic-errors is specified.  In the later case, we always want
4935          an error.  In the former case, we simply want a warning.  */
4936       if (require_constant && pedantic
4937           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4938         {
4939           inside_init
4940             = valid_compound_expr_initializer (inside_init,
4941                                                TREE_TYPE (inside_init));
4942           if (inside_init == error_mark_node)
4943             error_init ("initializer element is not constant");
4944           else
4945             pedwarn_init (input_location, OPT_pedantic,
4946                           "initializer element is not constant");
4947           if (flag_pedantic_errors)
4948             inside_init = error_mark_node;
4949         }
4950       else if (require_constant
4951                && !initializer_constant_valid_p (inside_init,
4952                                                  TREE_TYPE (inside_init)))
4953         {
4954           error_init ("initializer element is not constant");
4955           inside_init = error_mark_node;
4956         }
4957
4958       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4959       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4960         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4961                                               NULL_TREE, 0);
4962       return inside_init;
4963     }
4964
4965   /* Handle scalar types, including conversions.  */
4966
4967   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4968       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4969       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4970     {
4971       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4972           && (TREE_CODE (init) == STRING_CST
4973               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4974         init = array_to_pointer_conversion (init);
4975       inside_init
4976         = convert_for_assignment (type, init, ic_init,
4977                                   NULL_TREE, NULL_TREE, 0);
4978
4979       /* Check to see if we have already given an error message.  */
4980       if (inside_init == error_mark_node)
4981         ;
4982       else if (require_constant && !TREE_CONSTANT (inside_init))
4983         {
4984           error_init ("initializer element is not constant");
4985           inside_init = error_mark_node;
4986         }
4987       else if (require_constant
4988                && !initializer_constant_valid_p (inside_init,
4989                                                  TREE_TYPE (inside_init)))
4990         {
4991           error_init ("initializer element is not computable at load time");
4992           inside_init = error_mark_node;
4993         }
4994
4995       return inside_init;
4996     }
4997
4998   /* Come here only for records and arrays.  */
4999
5000   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5001     {
5002       error_init ("variable-sized object may not be initialized");
5003       return error_mark_node;
5004     }
5005
5006   error_init ("invalid initializer");
5007   return error_mark_node;
5008 }
5009 \f
5010 /* Handle initializers that use braces.  */
5011
5012 /* Type of object we are accumulating a constructor for.
5013    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5014 static tree constructor_type;
5015
5016 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5017    left to fill.  */
5018 static tree constructor_fields;
5019
5020 /* For an ARRAY_TYPE, this is the specified index
5021    at which to store the next element we get.  */
5022 static tree constructor_index;
5023
5024 /* For an ARRAY_TYPE, this is the maximum index.  */
5025 static tree constructor_max_index;
5026
5027 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5028 static tree constructor_unfilled_fields;
5029
5030 /* For an ARRAY_TYPE, this is the index of the first element
5031    not yet written out.  */
5032 static tree constructor_unfilled_index;
5033
5034 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5035    This is so we can generate gaps between fields, when appropriate.  */
5036 static tree constructor_bit_index;
5037
5038 /* If we are saving up the elements rather than allocating them,
5039    this is the list of elements so far (in reverse order,
5040    most recent first).  */
5041 static VEC(constructor_elt,gc) *constructor_elements;
5042
5043 /* 1 if constructor should be incrementally stored into a constructor chain,
5044    0 if all the elements should be kept in AVL tree.  */
5045 static int constructor_incremental;
5046
5047 /* 1 if so far this constructor's elements are all compile-time constants.  */
5048 static int constructor_constant;
5049
5050 /* 1 if so far this constructor's elements are all valid address constants.  */
5051 static int constructor_simple;
5052
5053 /* 1 if this constructor is erroneous so far.  */
5054 static int constructor_erroneous;
5055
5056 /* Structure for managing pending initializer elements, organized as an
5057    AVL tree.  */
5058
5059 struct init_node
5060 {
5061   struct init_node *left, *right;
5062   struct init_node *parent;
5063   int balance;
5064   tree purpose;
5065   tree value;
5066 };
5067
5068 /* Tree of pending elements at this constructor level.
5069    These are elements encountered out of order
5070    which belong at places we haven't reached yet in actually
5071    writing the output.
5072    Will never hold tree nodes across GC runs.  */
5073 static struct init_node *constructor_pending_elts;
5074
5075 /* The SPELLING_DEPTH of this constructor.  */
5076 static int constructor_depth;
5077
5078 /* DECL node for which an initializer is being read.
5079    0 means we are reading a constructor expression
5080    such as (struct foo) {...}.  */
5081 static tree constructor_decl;
5082
5083 /* Nonzero if this is an initializer for a top-level decl.  */
5084 static int constructor_top_level;
5085
5086 /* Nonzero if there were any member designators in this initializer.  */
5087 static int constructor_designated;
5088
5089 /* Nesting depth of designator list.  */
5090 static int designator_depth;
5091
5092 /* Nonzero if there were diagnosed errors in this designator list.  */
5093 static int designator_erroneous;
5094
5095 \f
5096 /* This stack has a level for each implicit or explicit level of
5097    structuring in the initializer, including the outermost one.  It
5098    saves the values of most of the variables above.  */
5099
5100 struct constructor_range_stack;
5101
5102 struct constructor_stack
5103 {
5104   struct constructor_stack *next;
5105   tree type;
5106   tree fields;
5107   tree index;
5108   tree max_index;
5109   tree unfilled_index;
5110   tree unfilled_fields;
5111   tree bit_index;
5112   VEC(constructor_elt,gc) *elements;
5113   struct init_node *pending_elts;
5114   int offset;
5115   int depth;
5116   /* If value nonzero, this value should replace the entire
5117      constructor at this level.  */
5118   struct c_expr replacement_value;
5119   struct constructor_range_stack *range_stack;
5120   char constant;
5121   char simple;
5122   char implicit;
5123   char erroneous;
5124   char outer;
5125   char incremental;
5126   char designated;
5127 };
5128
5129 static struct constructor_stack *constructor_stack;
5130
5131 /* This stack represents designators from some range designator up to
5132    the last designator in the list.  */
5133
5134 struct constructor_range_stack
5135 {
5136   struct constructor_range_stack *next, *prev;
5137   struct constructor_stack *stack;
5138   tree range_start;
5139   tree index;
5140   tree range_end;
5141   tree fields;
5142 };
5143
5144 static struct constructor_range_stack *constructor_range_stack;
5145
5146 /* This stack records separate initializers that are nested.
5147    Nested initializers can't happen in ANSI C, but GNU C allows them
5148    in cases like { ... (struct foo) { ... } ... }.  */
5149
5150 struct initializer_stack
5151 {
5152   struct initializer_stack *next;
5153   tree decl;
5154   struct constructor_stack *constructor_stack;
5155   struct constructor_range_stack *constructor_range_stack;
5156   VEC(constructor_elt,gc) *elements;
5157   struct spelling *spelling;
5158   struct spelling *spelling_base;
5159   int spelling_size;
5160   char top_level;
5161   char require_constant_value;
5162   char require_constant_elements;
5163 };
5164
5165 static struct initializer_stack *initializer_stack;
5166 \f
5167 /* Prepare to parse and output the initializer for variable DECL.  */
5168
5169 void
5170 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5171 {
5172   const char *locus;
5173   struct initializer_stack *p = XNEW (struct initializer_stack);
5174
5175   p->decl = constructor_decl;
5176   p->require_constant_value = require_constant_value;
5177   p->require_constant_elements = require_constant_elements;
5178   p->constructor_stack = constructor_stack;
5179   p->constructor_range_stack = constructor_range_stack;
5180   p->elements = constructor_elements;
5181   p->spelling = spelling;
5182   p->spelling_base = spelling_base;
5183   p->spelling_size = spelling_size;
5184   p->top_level = constructor_top_level;
5185   p->next = initializer_stack;
5186   initializer_stack = p;
5187
5188   constructor_decl = decl;
5189   constructor_designated = 0;
5190   constructor_top_level = top_level;
5191
5192   if (decl != 0 && decl != error_mark_node)
5193     {
5194       require_constant_value = TREE_STATIC (decl);
5195       require_constant_elements
5196         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5197            /* For a scalar, you can always use any value to initialize,
5198               even within braces.  */
5199            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5200                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5201                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5202                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5203       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5204     }
5205   else
5206     {
5207       require_constant_value = 0;
5208       require_constant_elements = 0;
5209       locus = "(anonymous)";
5210     }
5211
5212   constructor_stack = 0;
5213   constructor_range_stack = 0;
5214
5215   missing_braces_mentioned = 0;
5216
5217   spelling_base = 0;
5218   spelling_size = 0;
5219   RESTORE_SPELLING_DEPTH (0);
5220
5221   if (locus)
5222     push_string (locus);
5223 }
5224
5225 void
5226 finish_init (void)
5227 {
5228   struct initializer_stack *p = initializer_stack;
5229
5230   /* Free the whole constructor stack of this initializer.  */
5231   while (constructor_stack)
5232     {
5233       struct constructor_stack *q = constructor_stack;
5234       constructor_stack = q->next;
5235       free (q);
5236     }
5237
5238   gcc_assert (!constructor_range_stack);
5239
5240   /* Pop back to the data of the outer initializer (if any).  */
5241   free (spelling_base);
5242
5243   constructor_decl = p->decl;
5244   require_constant_value = p->require_constant_value;
5245   require_constant_elements = p->require_constant_elements;
5246   constructor_stack = p->constructor_stack;
5247   constructor_range_stack = p->constructor_range_stack;
5248   constructor_elements = p->elements;
5249   spelling = p->spelling;
5250   spelling_base = p->spelling_base;
5251   spelling_size = p->spelling_size;
5252   constructor_top_level = p->top_level;
5253   initializer_stack = p->next;
5254   free (p);
5255 }
5256 \f
5257 /* Call here when we see the initializer is surrounded by braces.
5258    This is instead of a call to push_init_level;
5259    it is matched by a call to pop_init_level.
5260
5261    TYPE is the type to initialize, for a constructor expression.
5262    For an initializer for a decl, TYPE is zero.  */
5263
5264 void
5265 really_start_incremental_init (tree type)
5266 {
5267   struct constructor_stack *p = XNEW (struct constructor_stack);
5268
5269   if (type == 0)
5270     type = TREE_TYPE (constructor_decl);
5271
5272   if (targetm.vector_opaque_p (type))
5273     error ("opaque vector types cannot be initialized");
5274
5275   p->type = constructor_type;
5276   p->fields = constructor_fields;
5277   p->index = constructor_index;
5278   p->max_index = constructor_max_index;
5279   p->unfilled_index = constructor_unfilled_index;
5280   p->unfilled_fields = constructor_unfilled_fields;
5281   p->bit_index = constructor_bit_index;
5282   p->elements = constructor_elements;
5283   p->constant = constructor_constant;
5284   p->simple = constructor_simple;
5285   p->erroneous = constructor_erroneous;
5286   p->pending_elts = constructor_pending_elts;
5287   p->depth = constructor_depth;
5288   p->replacement_value.value = 0;
5289   p->replacement_value.original_code = ERROR_MARK;
5290   p->implicit = 0;
5291   p->range_stack = 0;
5292   p->outer = 0;
5293   p->incremental = constructor_incremental;
5294   p->designated = constructor_designated;
5295   p->next = 0;
5296   constructor_stack = p;
5297
5298   constructor_constant = 1;
5299   constructor_simple = 1;
5300   constructor_depth = SPELLING_DEPTH ();
5301   constructor_elements = 0;
5302   constructor_pending_elts = 0;
5303   constructor_type = type;
5304   constructor_incremental = 1;
5305   constructor_designated = 0;
5306   designator_depth = 0;
5307   designator_erroneous = 0;
5308
5309   if (TREE_CODE (constructor_type) == RECORD_TYPE
5310       || TREE_CODE (constructor_type) == UNION_TYPE)
5311     {
5312       constructor_fields = TYPE_FIELDS (constructor_type);
5313       /* Skip any nameless bit fields at the beginning.  */
5314       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5315              && DECL_NAME (constructor_fields) == 0)
5316         constructor_fields = TREE_CHAIN (constructor_fields);
5317
5318       constructor_unfilled_fields = constructor_fields;
5319       constructor_bit_index = bitsize_zero_node;
5320     }
5321   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5322     {
5323       if (TYPE_DOMAIN (constructor_type))
5324         {
5325           constructor_max_index
5326             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5327
5328           /* Detect non-empty initializations of zero-length arrays.  */
5329           if (constructor_max_index == NULL_TREE
5330               && TYPE_SIZE (constructor_type))
5331             constructor_max_index = build_int_cst (NULL_TREE, -1);
5332
5333           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5334              to initialize VLAs will cause a proper error; avoid tree
5335              checking errors as well by setting a safe value.  */
5336           if (constructor_max_index
5337               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5338             constructor_max_index = build_int_cst (NULL_TREE, -1);
5339
5340           constructor_index
5341             = convert (bitsizetype,
5342                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5343         }
5344       else
5345         {
5346           constructor_index = bitsize_zero_node;
5347           constructor_max_index = NULL_TREE;
5348         }
5349
5350       constructor_unfilled_index = constructor_index;
5351     }
5352   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5353     {
5354       /* Vectors are like simple fixed-size arrays.  */
5355       constructor_max_index =
5356         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5357       constructor_index = bitsize_zero_node;
5358       constructor_unfilled_index = constructor_index;
5359     }
5360   else
5361     {
5362       /* Handle the case of int x = {5}; */
5363       constructor_fields = constructor_type;
5364       constructor_unfilled_fields = constructor_type;
5365     }
5366 }
5367 \f
5368 /* Push down into a subobject, for initialization.
5369    If this is for an explicit set of braces, IMPLICIT is 0.
5370    If it is because the next element belongs at a lower level,
5371    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5372
5373 void
5374 push_init_level (int implicit)
5375 {
5376   struct constructor_stack *p;
5377   tree value = NULL_TREE;
5378
5379   /* If we've exhausted any levels that didn't have braces,
5380      pop them now.  If implicit == 1, this will have been done in
5381      process_init_element; do not repeat it here because in the case
5382      of excess initializers for an empty aggregate this leads to an
5383      infinite cycle of popping a level and immediately recreating
5384      it.  */
5385   if (implicit != 1)
5386     {
5387       while (constructor_stack->implicit)
5388         {
5389           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5390                || TREE_CODE (constructor_type) == UNION_TYPE)
5391               && constructor_fields == 0)
5392             process_init_element (pop_init_level (1), true);
5393           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5394                    && constructor_max_index
5395                    && tree_int_cst_lt (constructor_max_index,
5396                                        constructor_index))
5397             process_init_element (pop_init_level (1), true);
5398           else
5399             break;
5400         }
5401     }
5402
5403   /* Unless this is an explicit brace, we need to preserve previous
5404      content if any.  */
5405   if (implicit)
5406     {
5407       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5408            || TREE_CODE (constructor_type) == UNION_TYPE)
5409           && constructor_fields)
5410         value = find_init_member (constructor_fields);
5411       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5412         value = find_init_member (constructor_index);
5413     }
5414
5415   p = XNEW (struct constructor_stack);
5416   p->type = constructor_type;
5417   p->fields = constructor_fields;
5418   p->index = constructor_index;
5419   p->max_index = constructor_max_index;
5420   p->unfilled_index = constructor_unfilled_index;
5421   p->unfilled_fields = constructor_unfilled_fields;
5422   p->bit_index = constructor_bit_index;
5423   p->elements = constructor_elements;
5424   p->constant = constructor_constant;
5425   p->simple = constructor_simple;
5426   p->erroneous = constructor_erroneous;
5427   p->pending_elts = constructor_pending_elts;
5428   p->depth = constructor_depth;
5429   p->replacement_value.value = 0;
5430   p->replacement_value.original_code = ERROR_MARK;
5431   p->implicit = implicit;
5432   p->outer = 0;
5433   p->incremental = constructor_incremental;
5434   p->designated = constructor_designated;
5435   p->next = constructor_stack;
5436   p->range_stack = 0;
5437   constructor_stack = p;
5438
5439   constructor_constant = 1;
5440   constructor_simple = 1;
5441   constructor_depth = SPELLING_DEPTH ();
5442   constructor_elements = 0;
5443   constructor_incremental = 1;
5444   constructor_designated = 0;
5445   constructor_pending_elts = 0;
5446   if (!implicit)
5447     {
5448       p->range_stack = constructor_range_stack;
5449       constructor_range_stack = 0;
5450       designator_depth = 0;
5451       designator_erroneous = 0;
5452     }
5453
5454   /* Don't die if an entire brace-pair level is superfluous
5455      in the containing level.  */
5456   if (constructor_type == 0)
5457     ;
5458   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5459            || TREE_CODE (constructor_type) == UNION_TYPE)
5460     {
5461       /* Don't die if there are extra init elts at the end.  */
5462       if (constructor_fields == 0)
5463         constructor_type = 0;
5464       else
5465         {
5466           constructor_type = TREE_TYPE (constructor_fields);
5467           push_member_name (constructor_fields);
5468           constructor_depth++;
5469         }
5470     }
5471   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5472     {
5473       constructor_type = TREE_TYPE (constructor_type);
5474       push_array_bounds (tree_low_cst (constructor_index, 1));
5475       constructor_depth++;
5476     }
5477
5478   if (constructor_type == 0)
5479     {
5480       error_init ("extra brace group at end of initializer");
5481       constructor_fields = 0;
5482       constructor_unfilled_fields = 0;
5483       return;
5484     }
5485
5486   if (value && TREE_CODE (value) == CONSTRUCTOR)
5487     {
5488       constructor_constant = TREE_CONSTANT (value);
5489       constructor_simple = TREE_STATIC (value);
5490       constructor_elements = CONSTRUCTOR_ELTS (value);
5491       if (!VEC_empty (constructor_elt, constructor_elements)
5492           && (TREE_CODE (constructor_type) == RECORD_TYPE
5493               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5494         set_nonincremental_init ();
5495     }
5496
5497   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5498     {
5499       missing_braces_mentioned = 1;
5500       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5501     }
5502
5503   if (TREE_CODE (constructor_type) == RECORD_TYPE
5504            || TREE_CODE (constructor_type) == UNION_TYPE)
5505     {
5506       constructor_fields = TYPE_FIELDS (constructor_type);
5507       /* Skip any nameless bit fields at the beginning.  */
5508       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5509              && DECL_NAME (constructor_fields) == 0)
5510         constructor_fields = TREE_CHAIN (constructor_fields);
5511
5512       constructor_unfilled_fields = constructor_fields;
5513       constructor_bit_index = bitsize_zero_node;
5514     }
5515   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5516     {
5517       /* Vectors are like simple fixed-size arrays.  */
5518       constructor_max_index =
5519         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5520       constructor_index = convert (bitsizetype, integer_zero_node);
5521       constructor_unfilled_index = constructor_index;
5522     }
5523   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5524     {
5525       if (TYPE_DOMAIN (constructor_type))
5526         {
5527           constructor_max_index
5528             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5529
5530           /* Detect non-empty initializations of zero-length arrays.  */
5531           if (constructor_max_index == NULL_TREE
5532               && TYPE_SIZE (constructor_type))
5533             constructor_max_index = build_int_cst (NULL_TREE, -1);
5534
5535           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5536              to initialize VLAs will cause a proper error; avoid tree
5537              checking errors as well by setting a safe value.  */
5538           if (constructor_max_index
5539               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5540             constructor_max_index = build_int_cst (NULL_TREE, -1);
5541
5542           constructor_index
5543             = convert (bitsizetype,
5544                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5545         }
5546       else
5547         constructor_index = bitsize_zero_node;
5548
5549       constructor_unfilled_index = constructor_index;
5550       if (value && TREE_CODE (value) == STRING_CST)
5551         {
5552           /* We need to split the char/wchar array into individual
5553              characters, so that we don't have to special case it
5554              everywhere.  */
5555           set_nonincremental_init_from_string (value);
5556         }
5557     }
5558   else
5559     {
5560       if (constructor_type != error_mark_node)
5561         warning_init (0, "braces around scalar initializer");
5562       constructor_fields = constructor_type;
5563       constructor_unfilled_fields = constructor_type;
5564     }
5565 }
5566
5567 /* At the end of an implicit or explicit brace level,
5568    finish up that level of constructor.  If a single expression
5569    with redundant braces initialized that level, return the
5570    c_expr structure for that expression.  Otherwise, the original_code
5571    element is set to ERROR_MARK.
5572    If we were outputting the elements as they are read, return 0 as the value
5573    from inner levels (process_init_element ignores that),
5574    but return error_mark_node as the value from the outermost level
5575    (that's what we want to put in DECL_INITIAL).
5576    Otherwise, return a CONSTRUCTOR expression as the value.  */
5577
5578 struct c_expr
5579 pop_init_level (int implicit)
5580 {
5581   struct constructor_stack *p;
5582   struct c_expr ret;
5583   ret.value = 0;
5584   ret.original_code = ERROR_MARK;
5585
5586   if (implicit == 0)
5587     {
5588       /* When we come to an explicit close brace,
5589          pop any inner levels that didn't have explicit braces.  */
5590       while (constructor_stack->implicit)
5591         process_init_element (pop_init_level (1), true);
5592
5593       gcc_assert (!constructor_range_stack);
5594     }
5595
5596   /* Now output all pending elements.  */
5597   constructor_incremental = 1;
5598   output_pending_init_elements (1);
5599
5600   p = constructor_stack;
5601
5602   /* Error for initializing a flexible array member, or a zero-length
5603      array member in an inappropriate context.  */
5604   if (constructor_type && constructor_fields
5605       && TREE_CODE (constructor_type) == ARRAY_TYPE
5606       && TYPE_DOMAIN (constructor_type)
5607       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5608     {
5609       /* Silently discard empty initializations.  The parser will
5610          already have pedwarned for empty brackets.  */
5611       if (integer_zerop (constructor_unfilled_index))
5612         constructor_type = NULL_TREE;
5613       else
5614         {
5615           gcc_assert (!TYPE_SIZE (constructor_type));
5616
5617           if (constructor_depth > 2)
5618             error_init ("initialization of flexible array member in a nested context");
5619           else
5620             pedwarn_init (input_location, OPT_pedantic,
5621                           "initialization of a flexible array member");
5622
5623           /* We have already issued an error message for the existence
5624              of a flexible array member not at the end of the structure.
5625              Discard the initializer so that we do not die later.  */
5626           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5627             constructor_type = NULL_TREE;
5628         }
5629     }
5630
5631   /* Warn when some struct elements are implicitly initialized to zero.  */
5632   if (warn_missing_field_initializers
5633       && constructor_type
5634       && TREE_CODE (constructor_type) == RECORD_TYPE
5635       && constructor_unfilled_fields)
5636     {
5637         /* Do not warn for flexible array members or zero-length arrays.  */
5638         while (constructor_unfilled_fields
5639                && (!DECL_SIZE (constructor_unfilled_fields)
5640                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5641           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5642
5643         /* Do not warn if this level of the initializer uses member
5644            designators; it is likely to be deliberate.  */
5645         if (constructor_unfilled_fields && !constructor_designated)
5646           {
5647             push_member_name (constructor_unfilled_fields);
5648             warning_init (OPT_Wmissing_field_initializers,
5649                           "missing initializer");
5650             RESTORE_SPELLING_DEPTH (constructor_depth);
5651           }
5652     }
5653
5654   /* Pad out the end of the structure.  */
5655   if (p->replacement_value.value)
5656     /* If this closes a superfluous brace pair,
5657        just pass out the element between them.  */
5658     ret = p->replacement_value;
5659   else if (constructor_type == 0)
5660     ;
5661   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5662            && TREE_CODE (constructor_type) != UNION_TYPE
5663            && TREE_CODE (constructor_type) != ARRAY_TYPE
5664            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5665     {
5666       /* A nonincremental scalar initializer--just return
5667          the element, after verifying there is just one.  */
5668       if (VEC_empty (constructor_elt,constructor_elements))
5669         {
5670           if (!constructor_erroneous)
5671             error_init ("empty scalar initializer");
5672           ret.value = error_mark_node;
5673         }
5674       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5675         {
5676           error_init ("extra elements in scalar initializer");
5677           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5678         }
5679       else
5680         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5681     }
5682   else
5683     {
5684       if (constructor_erroneous)
5685         ret.value = error_mark_node;
5686       else
5687         {
5688           ret.value = build_constructor (constructor_type,
5689                                          constructor_elements);
5690           if (constructor_constant)
5691             TREE_CONSTANT (ret.value) = 1;
5692           if (constructor_constant && constructor_simple)
5693             TREE_STATIC (ret.value) = 1;
5694         }
5695     }
5696
5697   constructor_type = p->type;
5698   constructor_fields = p->fields;
5699   constructor_index = p->index;
5700   constructor_max_index = p->max_index;
5701   constructor_unfilled_index = p->unfilled_index;
5702   constructor_unfilled_fields = p->unfilled_fields;
5703   constructor_bit_index = p->bit_index;
5704   constructor_elements = p->elements;
5705   constructor_constant = p->constant;
5706   constructor_simple = p->simple;
5707   constructor_erroneous = p->erroneous;
5708   constructor_incremental = p->incremental;
5709   constructor_designated = p->designated;
5710   constructor_pending_elts = p->pending_elts;
5711   constructor_depth = p->depth;
5712   if (!p->implicit)
5713     constructor_range_stack = p->range_stack;
5714   RESTORE_SPELLING_DEPTH (constructor_depth);
5715
5716   constructor_stack = p->next;
5717   free (p);
5718
5719   if (ret.value == 0 && constructor_stack == 0)
5720     ret.value = error_mark_node;
5721   return ret;
5722 }
5723
5724 /* Common handling for both array range and field name designators.
5725    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5726
5727 static int
5728 set_designator (int array)
5729 {
5730   tree subtype;
5731   enum tree_code subcode;
5732
5733   /* Don't die if an entire brace-pair level is superfluous
5734      in the containing level.  */
5735   if (constructor_type == 0)
5736     return 1;
5737
5738   /* If there were errors in this designator list already, bail out
5739      silently.  */
5740   if (designator_erroneous)
5741     return 1;
5742
5743   if (!designator_depth)
5744     {
5745       gcc_assert (!constructor_range_stack);
5746
5747       /* Designator list starts at the level of closest explicit
5748          braces.  */
5749       while (constructor_stack->implicit)
5750         process_init_element (pop_init_level (1), true);
5751       constructor_designated = 1;
5752       return 0;
5753     }
5754
5755   switch (TREE_CODE (constructor_type))
5756     {
5757     case  RECORD_TYPE:
5758     case  UNION_TYPE:
5759       subtype = TREE_TYPE (constructor_fields);
5760       if (subtype != error_mark_node)
5761         subtype = TYPE_MAIN_VARIANT (subtype);
5762       break;
5763     case ARRAY_TYPE:
5764       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5765       break;
5766     default:
5767       gcc_unreachable ();
5768     }
5769
5770   subcode = TREE_CODE (subtype);
5771   if (array && subcode != ARRAY_TYPE)
5772     {
5773       error_init ("array index in non-array initializer");
5774       return 1;
5775     }
5776   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5777     {
5778       error_init ("field name not in record or union initializer");
5779       return 1;
5780     }
5781
5782   constructor_designated = 1;
5783   push_init_level (2);
5784   return 0;
5785 }
5786
5787 /* If there are range designators in designator list, push a new designator
5788    to constructor_range_stack.  RANGE_END is end of such stack range or
5789    NULL_TREE if there is no range designator at this level.  */
5790
5791 static void
5792 push_range_stack (tree range_end)
5793 {
5794   struct constructor_range_stack *p;
5795
5796   p = GGC_NEW (struct constructor_range_stack);
5797   p->prev = constructor_range_stack;
5798   p->next = 0;
5799   p->fields = constructor_fields;
5800   p->range_start = constructor_index;
5801   p->index = constructor_index;
5802   p->stack = constructor_stack;
5803   p->range_end = range_end;
5804   if (constructor_range_stack)
5805     constructor_range_stack->next = p;
5806   constructor_range_stack = p;
5807 }
5808
5809 /* Within an array initializer, specify the next index to be initialized.
5810    FIRST is that index.  If LAST is nonzero, then initialize a range
5811    of indices, running from FIRST through LAST.  */
5812
5813 void
5814 set_init_index (tree first, tree last)
5815 {
5816   if (set_designator (1))
5817     return;
5818
5819   designator_erroneous = 1;
5820
5821   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5822       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5823     {
5824       error_init ("array index in initializer not of integer type");
5825       return;
5826     }
5827
5828   if (TREE_CODE (first) != INTEGER_CST)
5829     error_init ("nonconstant array index in initializer");
5830   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5831     error_init ("nonconstant array index in initializer");
5832   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5833     error_init ("array index in non-array initializer");
5834   else if (tree_int_cst_sgn (first) == -1)
5835     error_init ("array index in initializer exceeds array bounds");
5836   else if (constructor_max_index
5837            && tree_int_cst_lt (constructor_max_index, first))
5838     error_init ("array index in initializer exceeds array bounds");
5839   else
5840     {
5841       constructor_index = convert (bitsizetype, first);
5842
5843       if (last)
5844         {
5845           if (tree_int_cst_equal (first, last))
5846             last = 0;
5847           else if (tree_int_cst_lt (last, first))
5848             {
5849               error_init ("empty index range in initializer");
5850               last = 0;
5851             }
5852           else
5853             {
5854               last = convert (bitsizetype, last);
5855               if (constructor_max_index != 0
5856                   && tree_int_cst_lt (constructor_max_index, last))
5857                 {
5858                   error_init ("array index range in initializer exceeds array bounds");
5859                   last = 0;
5860                 }
5861             }
5862         }
5863
5864       designator_depth++;
5865       designator_erroneous = 0;
5866       if (constructor_range_stack || last)
5867         push_range_stack (last);
5868     }
5869 }
5870
5871 /* Within a struct initializer, specify the next field to be initialized.  */
5872
5873 void
5874 set_init_label (tree fieldname)
5875 {
5876   tree tail;
5877
5878   if (set_designator (0))
5879     return;
5880
5881   designator_erroneous = 1;
5882
5883   if (TREE_CODE (constructor_type) != RECORD_TYPE
5884       && TREE_CODE (constructor_type) != UNION_TYPE)
5885     {
5886       error_init ("field name not in record or union initializer");
5887       return;
5888     }
5889
5890   for (tail = TYPE_FIELDS (constructor_type); tail;
5891        tail = TREE_CHAIN (tail))
5892     {
5893       if (DECL_NAME (tail) == fieldname)
5894         break;
5895     }
5896
5897   if (tail == 0)
5898     error ("unknown field %qE specified in initializer", fieldname);
5899   else
5900     {
5901       constructor_fields = tail;
5902       designator_depth++;
5903       designator_erroneous = 0;
5904       if (constructor_range_stack)
5905         push_range_stack (NULL_TREE);
5906     }
5907 }
5908 \f
5909 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5910    identifies the initializer, either array index or field in a structure.
5911    VALUE is the value of that index or field.
5912
5913    IMPLICIT is true if value comes from pop_init_level (1),
5914    the new initializer has been merged with the existing one
5915    and thus no warnings should be emitted about overriding an
5916    existing initializer.  */
5917
5918 static void
5919 add_pending_init (tree purpose, tree value, bool implicit)
5920 {
5921   struct init_node *p, **q, *r;
5922
5923   q = &constructor_pending_elts;
5924   p = 0;
5925
5926   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5927     {
5928       while (*q != 0)
5929         {
5930           p = *q;
5931           if (tree_int_cst_lt (purpose, p->purpose))
5932             q = &p->left;
5933           else if (tree_int_cst_lt (p->purpose, purpose))
5934             q = &p->right;
5935           else
5936             {
5937               if (!implicit)
5938                 {
5939                   if (TREE_SIDE_EFFECTS (p->value))
5940                     warning_init (0, "initialized field with side-effects overwritten");
5941                   else if (warn_override_init)
5942                     warning_init (OPT_Woverride_init, "initialized field overwritten");
5943                 }
5944               p->value = value;
5945               return;
5946             }
5947         }
5948     }
5949   else
5950     {
5951       tree bitpos;
5952
5953       bitpos = bit_position (purpose);
5954       while (*q != NULL)
5955         {
5956           p = *q;
5957           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5958             q = &p->left;
5959           else if (p->purpose != purpose)
5960             q = &p->right;
5961           else
5962             {
5963               if (!implicit)
5964                 {
5965                   if (TREE_SIDE_EFFECTS (p->value))
5966                     warning_init (0, "initialized field with side-effects overwritten");
5967                   else if (warn_override_init)
5968                     warning_init (OPT_Woverride_init, "initialized field overwritten");
5969                 }
5970               p->value = value;
5971               return;
5972             }
5973         }
5974     }
5975
5976   r = GGC_NEW (struct init_node);
5977   r->purpose = purpose;
5978   r->value = value;
5979
5980   *q = r;
5981   r->parent = p;
5982   r->left = 0;
5983   r->right = 0;
5984   r->balance = 0;
5985
5986   while (p)
5987     {
5988       struct init_node *s;
5989
5990       if (r == p->left)
5991         {
5992           if (p->balance == 0)
5993             p->balance = -1;
5994           else if (p->balance < 0)
5995             {
5996               if (r->balance < 0)
5997                 {
5998                   /* L rotation.  */
5999                   p->left = r->right;
6000                   if (p->left)
6001                     p->left->parent = p;
6002                   r->right = p;
6003
6004                   p->balance = 0;
6005                   r->balance = 0;
6006
6007                   s = p->parent;
6008                   p->parent = r;
6009                   r->parent = s;
6010                   if (s)
6011                     {
6012                       if (s->left == p)
6013                         s->left = r;
6014                       else
6015                         s->right = r;
6016                     }
6017                   else
6018                     constructor_pending_elts = r;
6019                 }
6020               else
6021                 {
6022                   /* LR rotation.  */
6023                   struct init_node *t = r->right;
6024
6025                   r->right = t->left;
6026                   if (r->right)
6027                     r->right->parent = r;
6028                   t->left = r;
6029
6030                   p->left = t->right;
6031                   if (p->left)
6032                     p->left->parent = p;
6033                   t->right = p;
6034
6035                   p->balance = t->balance < 0;
6036                   r->balance = -(t->balance > 0);
6037                   t->balance = 0;
6038
6039                   s = p->parent;
6040                   p->parent = t;
6041                   r->parent = t;
6042                   t->parent = s;
6043                   if (s)
6044                     {
6045                       if (s->left == p)
6046                         s->left = t;
6047                       else
6048                         s->right = t;
6049                     }
6050                   else
6051                     constructor_pending_elts = t;
6052                 }
6053               break;
6054             }
6055           else
6056             {
6057               /* p->balance == +1; growth of left side balances the node.  */
6058               p->balance = 0;
6059               break;
6060             }
6061         }
6062       else /* r == p->right */
6063         {
6064           if (p->balance == 0)
6065             /* Growth propagation from right side.  */
6066             p->balance++;
6067           else if (p->balance > 0)
6068             {
6069               if (r->balance > 0)
6070                 {
6071                   /* R rotation.  */
6072                   p->right = r->left;
6073                   if (p->right)
6074                     p->right->parent = p;
6075                   r->left = p;
6076
6077                   p->balance = 0;
6078                   r->balance = 0;
6079
6080                   s = p->parent;
6081                   p->parent = r;
6082                   r->parent = s;
6083                   if (s)
6084                     {
6085                       if (s->left == p)
6086                         s->left = r;
6087                       else
6088                         s->right = r;
6089                     }
6090                   else
6091                     constructor_pending_elts = r;
6092                 }
6093               else /* r->balance == -1 */
6094                 {
6095                   /* RL rotation */
6096                   struct init_node *t = r->left;
6097
6098                   r->left = t->right;
6099                   if (r->left)
6100                     r->left->parent = r;
6101                   t->right = r;
6102
6103                   p->right = t->left;
6104                   if (p->right)
6105                     p->right->parent = p;
6106                   t->left = p;
6107
6108                   r->balance = (t->balance < 0);
6109                   p->balance = -(t->balance > 0);
6110                   t->balance = 0;
6111
6112                   s = p->parent;
6113                   p->parent = t;
6114                   r->parent = t;
6115                   t->parent = s;
6116                   if (s)
6117                     {
6118                       if (s->left == p)
6119                         s->left = t;
6120                       else
6121                         s->right = t;
6122                     }
6123                   else
6124                     constructor_pending_elts = t;
6125                 }
6126               break;
6127             }
6128           else
6129             {
6130               /* p->balance == -1; growth of right side balances the node.  */
6131               p->balance = 0;
6132               break;
6133             }
6134         }
6135
6136       r = p;
6137       p = p->parent;
6138     }
6139 }
6140
6141 /* Build AVL tree from a sorted chain.  */
6142
6143 static void
6144 set_nonincremental_init (void)
6145 {
6146   unsigned HOST_WIDE_INT ix;
6147   tree index, value;
6148
6149   if (TREE_CODE (constructor_type) != RECORD_TYPE
6150       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6151     return;
6152
6153   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6154     add_pending_init (index, value, false);
6155   constructor_elements = 0;
6156   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6157     {
6158       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6159       /* Skip any nameless bit fields at the beginning.  */
6160       while (constructor_unfilled_fields != 0
6161              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6162              && DECL_NAME (constructor_unfilled_fields) == 0)
6163         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6164
6165     }
6166   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6167     {
6168       if (TYPE_DOMAIN (constructor_type))
6169         constructor_unfilled_index
6170             = convert (bitsizetype,
6171                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6172       else
6173         constructor_unfilled_index = bitsize_zero_node;
6174     }
6175   constructor_incremental = 0;
6176 }
6177
6178 /* Build AVL tree from a string constant.  */
6179
6180 static void
6181 set_nonincremental_init_from_string (tree str)
6182 {
6183   tree value, purpose, type;
6184   HOST_WIDE_INT val[2];
6185   const char *p, *end;
6186   int byte, wchar_bytes, charwidth, bitpos;
6187
6188   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6189
6190   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6191   charwidth = TYPE_PRECISION (char_type_node);
6192   type = TREE_TYPE (constructor_type);
6193   p = TREE_STRING_POINTER (str);
6194   end = p + TREE_STRING_LENGTH (str);
6195
6196   for (purpose = bitsize_zero_node;
6197        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6198        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6199     {
6200       if (wchar_bytes == 1)
6201         {
6202           val[1] = (unsigned char) *p++;
6203           val[0] = 0;
6204         }
6205       else
6206         {
6207           val[0] = 0;
6208           val[1] = 0;
6209           for (byte = 0; byte < wchar_bytes; byte++)
6210             {
6211               if (BYTES_BIG_ENDIAN)
6212                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6213               else
6214                 bitpos = byte * charwidth;
6215               val[bitpos < HOST_BITS_PER_WIDE_INT]
6216                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6217                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6218             }
6219         }
6220
6221       if (!TYPE_UNSIGNED (type))
6222         {
6223           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6224           if (bitpos < HOST_BITS_PER_WIDE_INT)
6225             {
6226               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6227                 {
6228                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6229                   val[0] = -1;
6230                 }
6231             }
6232           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6233             {
6234               if (val[1] < 0)
6235                 val[0] = -1;
6236             }
6237           else if (val[0] & (((HOST_WIDE_INT) 1)
6238                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6239             val[0] |= ((HOST_WIDE_INT) -1)
6240                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6241         }
6242
6243       value = build_int_cst_wide (type, val[1], val[0]);
6244       add_pending_init (purpose, value, false);
6245     }
6246
6247   constructor_incremental = 0;
6248 }
6249
6250 /* Return value of FIELD in pending initializer or zero if the field was
6251    not initialized yet.  */
6252
6253 static tree
6254 find_init_member (tree field)
6255 {
6256   struct init_node *p;
6257
6258   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6259     {
6260       if (constructor_incremental
6261           && tree_int_cst_lt (field, constructor_unfilled_index))
6262         set_nonincremental_init ();
6263
6264       p = constructor_pending_elts;
6265       while (p)
6266         {
6267           if (tree_int_cst_lt (field, p->purpose))
6268             p = p->left;
6269           else if (tree_int_cst_lt (p->purpose, field))
6270             p = p->right;
6271           else
6272             return p->value;
6273         }
6274     }
6275   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6276     {
6277       tree bitpos = bit_position (field);
6278
6279       if (constructor_incremental
6280           && (!constructor_unfilled_fields
6281               || tree_int_cst_lt (bitpos,
6282                                   bit_position (constructor_unfilled_fields))))
6283         set_nonincremental_init ();
6284
6285       p = constructor_pending_elts;
6286       while (p)
6287         {
6288           if (field == p->purpose)
6289             return p->value;
6290           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6291             p = p->left;
6292           else
6293             p = p->right;
6294         }
6295     }
6296   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6297     {
6298       if (!VEC_empty (constructor_elt, constructor_elements)
6299           && (VEC_last (constructor_elt, constructor_elements)->index
6300               == field))
6301         return VEC_last (constructor_elt, constructor_elements)->value;
6302     }
6303   return 0;
6304 }
6305
6306 /* "Output" the next constructor element.
6307    At top level, really output it to assembler code now.
6308    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6309    TYPE is the data type that the containing data type wants here.
6310    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6311    If VALUE is a string constant, STRICT_STRING is true if it is
6312    unparenthesized or we should not warn here for it being parenthesized.
6313    For other types of VALUE, STRICT_STRING is not used.
6314
6315    PENDING if non-nil means output pending elements that belong
6316    right after this element.  (PENDING is normally 1;
6317    it is 0 while outputting pending elements, to avoid recursion.)
6318
6319    IMPLICIT is true if value comes from pop_init_level (1),
6320    the new initializer has been merged with the existing one
6321    and thus no warnings should be emitted about overriding an
6322    existing initializer.  */
6323
6324 static void
6325 output_init_element (tree value, bool strict_string, tree type, tree field,
6326                      int pending, bool implicit)
6327 {
6328   constructor_elt *celt;
6329
6330   if (type == error_mark_node || value == error_mark_node)
6331     {
6332       constructor_erroneous = 1;
6333       return;
6334     }
6335   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6336       && (TREE_CODE (value) == STRING_CST
6337           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6338       && !(TREE_CODE (value) == STRING_CST
6339            && TREE_CODE (type) == ARRAY_TYPE
6340            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6341       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6342                      TYPE_MAIN_VARIANT (type)))
6343     value = array_to_pointer_conversion (value);
6344
6345   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6346       && require_constant_value && !flag_isoc99 && pending)
6347     {
6348       /* As an extension, allow initializing objects with static storage
6349          duration with compound literals (which are then treated just as
6350          the brace enclosed list they contain).  */
6351       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6352       value = DECL_INITIAL (decl);
6353     }
6354
6355   if (value == error_mark_node)
6356     constructor_erroneous = 1;
6357   else if (!TREE_CONSTANT (value))
6358     constructor_constant = 0;
6359   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6360            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6361                 || TREE_CODE (constructor_type) == UNION_TYPE)
6362                && DECL_C_BIT_FIELD (field)
6363                && TREE_CODE (value) != INTEGER_CST))
6364     constructor_simple = 0;
6365
6366   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6367     {
6368       if (require_constant_value)
6369         {
6370           error_init ("initializer element is not constant");
6371           value = error_mark_node;
6372         }
6373       else if (require_constant_elements)
6374         pedwarn (input_location, 0,
6375                  "initializer element is not computable at load time");
6376     }
6377
6378   /* If this field is empty (and not at the end of structure),
6379      don't do anything other than checking the initializer.  */
6380   if (field
6381       && (TREE_TYPE (field) == error_mark_node
6382           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6383               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6384               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6385                   || TREE_CHAIN (field)))))
6386     return;
6387
6388   value = digest_init (type, value, strict_string, require_constant_value);
6389   if (value == error_mark_node)
6390     {
6391       constructor_erroneous = 1;
6392       return;
6393     }
6394
6395   /* If this element doesn't come next in sequence,
6396      put it on constructor_pending_elts.  */
6397   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6398       && (!constructor_incremental
6399           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6400     {
6401       if (constructor_incremental
6402           && tree_int_cst_lt (field, constructor_unfilled_index))
6403         set_nonincremental_init ();
6404
6405       add_pending_init (field, value, implicit);
6406       return;
6407     }
6408   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6409            && (!constructor_incremental
6410                || field != constructor_unfilled_fields))
6411     {
6412       /* We do this for records but not for unions.  In a union,
6413          no matter which field is specified, it can be initialized
6414          right away since it starts at the beginning of the union.  */
6415       if (constructor_incremental)
6416         {
6417           if (!constructor_unfilled_fields)
6418             set_nonincremental_init ();
6419           else
6420             {
6421               tree bitpos, unfillpos;
6422
6423               bitpos = bit_position (field);
6424               unfillpos = bit_position (constructor_unfilled_fields);
6425
6426               if (tree_int_cst_lt (bitpos, unfillpos))
6427                 set_nonincremental_init ();
6428             }
6429         }
6430
6431       add_pending_init (field, value, implicit);
6432       return;
6433     }
6434   else if (TREE_CODE (constructor_type) == UNION_TYPE
6435            && !VEC_empty (constructor_elt, constructor_elements))
6436     {
6437       if (!implicit)
6438         {
6439           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6440                                            constructor_elements)->value))
6441             warning_init (0,
6442                           "initialized field with side-effects overwritten");
6443           else if (warn_override_init)
6444             warning_init (OPT_Woverride_init, "initialized field overwritten");
6445         }
6446
6447       /* We can have just one union field set.  */
6448       constructor_elements = 0;
6449     }
6450
6451   /* Otherwise, output this element either to
6452      constructor_elements or to the assembler file.  */
6453
6454   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6455   celt->index = field;
6456   celt->value = value;
6457
6458   /* Advance the variable that indicates sequential elements output.  */
6459   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6460     constructor_unfilled_index
6461       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6462                     bitsize_one_node);
6463   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6464     {
6465       constructor_unfilled_fields
6466         = TREE_CHAIN (constructor_unfilled_fields);
6467
6468       /* Skip any nameless bit fields.  */
6469       while (constructor_unfilled_fields != 0
6470              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6471              && DECL_NAME (constructor_unfilled_fields) == 0)
6472         constructor_unfilled_fields =
6473           TREE_CHAIN (constructor_unfilled_fields);
6474     }
6475   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6476     constructor_unfilled_fields = 0;
6477
6478   /* Now output any pending elements which have become next.  */
6479   if (pending)
6480     output_pending_init_elements (0);
6481 }
6482
6483 /* Output any pending elements which have become next.
6484    As we output elements, constructor_unfilled_{fields,index}
6485    advances, which may cause other elements to become next;
6486    if so, they too are output.
6487
6488    If ALL is 0, we return when there are
6489    no more pending elements to output now.
6490
6491    If ALL is 1, we output space as necessary so that
6492    we can output all the pending elements.  */
6493
6494 static void
6495 output_pending_init_elements (int all)
6496 {
6497   struct init_node *elt = constructor_pending_elts;
6498   tree next;
6499
6500  retry:
6501
6502   /* Look through the whole pending tree.
6503      If we find an element that should be output now,
6504      output it.  Otherwise, set NEXT to the element
6505      that comes first among those still pending.  */
6506
6507   next = 0;
6508   while (elt)
6509     {
6510       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6511         {
6512           if (tree_int_cst_equal (elt->purpose,
6513                                   constructor_unfilled_index))
6514             output_init_element (elt->value, true,
6515                                  TREE_TYPE (constructor_type),
6516                                  constructor_unfilled_index, 0, false);
6517           else if (tree_int_cst_lt (constructor_unfilled_index,
6518                                     elt->purpose))
6519             {
6520               /* Advance to the next smaller node.  */
6521               if (elt->left)
6522                 elt = elt->left;
6523               else
6524                 {
6525                   /* We have reached the smallest node bigger than the
6526                      current unfilled index.  Fill the space first.  */
6527                   next = elt->purpose;
6528                   break;
6529                 }
6530             }
6531           else
6532             {
6533               /* Advance to the next bigger node.  */
6534               if (elt->right)
6535                 elt = elt->right;
6536               else
6537                 {
6538                   /* We have reached the biggest node in a subtree.  Find
6539                      the parent of it, which is the next bigger node.  */
6540                   while (elt->parent && elt->parent->right == elt)
6541                     elt = elt->parent;
6542                   elt = elt->parent;
6543                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6544                                               elt->purpose))
6545                     {
6546                       next = elt->purpose;
6547                       break;
6548                     }
6549                 }
6550             }
6551         }
6552       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6553                || TREE_CODE (constructor_type) == UNION_TYPE)
6554         {
6555           tree ctor_unfilled_bitpos, elt_bitpos;
6556
6557           /* If the current record is complete we are done.  */
6558           if (constructor_unfilled_fields == 0)
6559             break;
6560
6561           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6562           elt_bitpos = bit_position (elt->purpose);
6563           /* We can't compare fields here because there might be empty
6564              fields in between.  */
6565           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6566             {
6567               constructor_unfilled_fields = elt->purpose;
6568               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6569                                    elt->purpose, 0, false);
6570             }
6571           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6572             {
6573               /* Advance to the next smaller node.  */
6574               if (elt->left)
6575                 elt = elt->left;
6576               else
6577                 {
6578                   /* We have reached the smallest node bigger than the
6579                      current unfilled field.  Fill the space first.  */
6580                   next = elt->purpose;
6581                   break;
6582                 }
6583             }
6584           else
6585             {
6586               /* Advance to the next bigger node.  */
6587               if (elt->right)
6588                 elt = elt->right;
6589               else
6590                 {
6591                   /* We have reached the biggest node in a subtree.  Find
6592                      the parent of it, which is the next bigger node.  */
6593                   while (elt->parent && elt->parent->right == elt)
6594                     elt = elt->parent;
6595                   elt = elt->parent;
6596                   if (elt
6597                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6598                                            bit_position (elt->purpose))))
6599                     {
6600                       next = elt->purpose;
6601                       break;
6602                     }
6603                 }
6604             }
6605         }
6606     }
6607
6608   /* Ordinarily return, but not if we want to output all
6609      and there are elements left.  */
6610   if (!(all && next != 0))
6611     return;
6612
6613   /* If it's not incremental, just skip over the gap, so that after
6614      jumping to retry we will output the next successive element.  */
6615   if (TREE_CODE (constructor_type) == RECORD_TYPE
6616       || TREE_CODE (constructor_type) == UNION_TYPE)
6617     constructor_unfilled_fields = next;
6618   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6619     constructor_unfilled_index = next;
6620
6621   /* ELT now points to the node in the pending tree with the next
6622      initializer to output.  */
6623   goto retry;
6624 }
6625 \f
6626 /* Add one non-braced element to the current constructor level.
6627    This adjusts the current position within the constructor's type.
6628    This may also start or terminate implicit levels
6629    to handle a partly-braced initializer.
6630
6631    Once this has found the correct level for the new element,
6632    it calls output_init_element.
6633
6634    IMPLICIT is true if value comes from pop_init_level (1),
6635    the new initializer has been merged with the existing one
6636    and thus no warnings should be emitted about overriding an
6637    existing initializer.  */
6638
6639 void
6640 process_init_element (struct c_expr value, bool implicit)
6641 {
6642   tree orig_value = value.value;
6643   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6644   bool strict_string = value.original_code == STRING_CST;
6645
6646   designator_depth = 0;
6647   designator_erroneous = 0;
6648
6649   /* Handle superfluous braces around string cst as in
6650      char x[] = {"foo"}; */
6651   if (string_flag
6652       && constructor_type
6653       && TREE_CODE (constructor_type) == ARRAY_TYPE
6654       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6655       && integer_zerop (constructor_unfilled_index))
6656     {
6657       if (constructor_stack->replacement_value.value)
6658         error_init ("excess elements in char array initializer");
6659       constructor_stack->replacement_value = value;
6660       return;
6661     }
6662
6663   if (constructor_stack->replacement_value.value != 0)
6664     {
6665       error_init ("excess elements in struct initializer");
6666       return;
6667     }
6668
6669   /* Ignore elements of a brace group if it is entirely superfluous
6670      and has already been diagnosed.  */
6671   if (constructor_type == 0)
6672     return;
6673
6674   /* If we've exhausted any levels that didn't have braces,
6675      pop them now.  */
6676   while (constructor_stack->implicit)
6677     {
6678       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6679            || TREE_CODE (constructor_type) == UNION_TYPE)
6680           && constructor_fields == 0)
6681         process_init_element (pop_init_level (1), true);
6682       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6683                && (constructor_max_index == 0
6684                    || tree_int_cst_lt (constructor_max_index,
6685                                        constructor_index)))
6686         process_init_element (pop_init_level (1), true);
6687       else
6688         break;
6689     }
6690
6691   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6692   if (constructor_range_stack)
6693     {
6694       /* If value is a compound literal and we'll be just using its
6695          content, don't put it into a SAVE_EXPR.  */
6696       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6697           || !require_constant_value
6698           || flag_isoc99)
6699         value.value = save_expr (value.value);
6700     }
6701
6702   while (1)
6703     {
6704       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6705         {
6706           tree fieldtype;
6707           enum tree_code fieldcode;
6708
6709           if (constructor_fields == 0)
6710             {
6711               pedwarn_init (input_location, 0,
6712                             "excess elements in struct initializer");
6713               break;
6714             }
6715
6716           fieldtype = TREE_TYPE (constructor_fields);
6717           if (fieldtype != error_mark_node)
6718             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6719           fieldcode = TREE_CODE (fieldtype);
6720
6721           /* Error for non-static initialization of a flexible array member.  */
6722           if (fieldcode == ARRAY_TYPE
6723               && !require_constant_value
6724               && TYPE_SIZE (fieldtype) == NULL_TREE
6725               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6726             {
6727               error_init ("non-static initialization of a flexible array member");
6728               break;
6729             }
6730
6731           /* Accept a string constant to initialize a subarray.  */
6732           if (value.value != 0
6733               && fieldcode == ARRAY_TYPE
6734               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6735               && string_flag)
6736             value.value = orig_value;
6737           /* Otherwise, if we have come to a subaggregate,
6738              and we don't have an element of its type, push into it.  */
6739           else if (value.value != 0
6740                    && value.value != error_mark_node
6741                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6742                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6743                        || fieldcode == UNION_TYPE))
6744             {
6745               push_init_level (1);
6746               continue;
6747             }
6748
6749           if (value.value)
6750             {
6751               push_member_name (constructor_fields);
6752               output_init_element (value.value, strict_string,
6753                                    fieldtype, constructor_fields, 1, implicit);
6754               RESTORE_SPELLING_DEPTH (constructor_depth);
6755             }
6756           else
6757             /* Do the bookkeeping for an element that was
6758                directly output as a constructor.  */
6759             {
6760               /* For a record, keep track of end position of last field.  */
6761               if (DECL_SIZE (constructor_fields))
6762                 constructor_bit_index
6763                   = size_binop (PLUS_EXPR,
6764                                 bit_position (constructor_fields),
6765                                 DECL_SIZE (constructor_fields));
6766
6767               /* If the current field was the first one not yet written out,
6768                  it isn't now, so update.  */
6769               if (constructor_unfilled_fields == constructor_fields)
6770                 {
6771                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6772                   /* Skip any nameless bit fields.  */
6773                   while (constructor_unfilled_fields != 0
6774                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6775                          && DECL_NAME (constructor_unfilled_fields) == 0)
6776                     constructor_unfilled_fields =
6777                       TREE_CHAIN (constructor_unfilled_fields);
6778                 }
6779             }
6780
6781           constructor_fields = TREE_CHAIN (constructor_fields);
6782           /* Skip any nameless bit fields at the beginning.  */
6783           while (constructor_fields != 0
6784                  && DECL_C_BIT_FIELD (constructor_fields)
6785                  && DECL_NAME (constructor_fields) == 0)
6786             constructor_fields = TREE_CHAIN (constructor_fields);
6787         }
6788       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6789         {
6790           tree fieldtype;
6791           enum tree_code fieldcode;
6792
6793           if (constructor_fields == 0)
6794             {
6795               pedwarn_init (input_location, 0,
6796                             "excess elements in union initializer");
6797               break;
6798             }
6799
6800           fieldtype = TREE_TYPE (constructor_fields);
6801           if (fieldtype != error_mark_node)
6802             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6803           fieldcode = TREE_CODE (fieldtype);
6804
6805           /* Warn that traditional C rejects initialization of unions.
6806              We skip the warning if the value is zero.  This is done
6807              under the assumption that the zero initializer in user
6808              code appears conditioned on e.g. __STDC__ to avoid
6809              "missing initializer" warnings and relies on default
6810              initialization to zero in the traditional C case.
6811              We also skip the warning if the initializer is designated,
6812              again on the assumption that this must be conditional on
6813              __STDC__ anyway (and we've already complained about the
6814              member-designator already).  */
6815           if (!in_system_header && !constructor_designated
6816               && !(value.value && (integer_zerop (value.value)
6817                                    || real_zerop (value.value))))
6818             warning (OPT_Wtraditional, "traditional C rejects initialization "
6819                      "of unions");
6820
6821           /* Accept a string constant to initialize a subarray.  */
6822           if (value.value != 0
6823               && fieldcode == ARRAY_TYPE
6824               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6825               && string_flag)
6826             value.value = orig_value;
6827           /* Otherwise, if we have come to a subaggregate,
6828              and we don't have an element of its type, push into it.  */
6829           else if (value.value != 0
6830                    && value.value != error_mark_node
6831                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6832                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6833                        || fieldcode == UNION_TYPE))
6834             {
6835               push_init_level (1);
6836               continue;
6837             }
6838
6839           if (value.value)
6840             {
6841               push_member_name (constructor_fields);
6842               output_init_element (value.value, strict_string,
6843                                    fieldtype, constructor_fields, 1, implicit);
6844               RESTORE_SPELLING_DEPTH (constructor_depth);
6845             }
6846           else
6847             /* Do the bookkeeping for an element that was
6848                directly output as a constructor.  */
6849             {
6850               constructor_bit_index = DECL_SIZE (constructor_fields);
6851               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6852             }
6853
6854           constructor_fields = 0;
6855         }
6856       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6857         {
6858           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6859           enum tree_code eltcode = TREE_CODE (elttype);
6860
6861           /* Accept a string constant to initialize a subarray.  */
6862           if (value.value != 0
6863               && eltcode == ARRAY_TYPE
6864               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6865               && string_flag)
6866             value.value = orig_value;
6867           /* Otherwise, if we have come to a subaggregate,
6868              and we don't have an element of its type, push into it.  */
6869           else if (value.value != 0
6870                    && value.value != error_mark_node
6871                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6872                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6873                        || eltcode == UNION_TYPE))
6874             {
6875               push_init_level (1);
6876               continue;
6877             }
6878
6879           if (constructor_max_index != 0
6880               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6881                   || integer_all_onesp (constructor_max_index)))
6882             {
6883               pedwarn_init (input_location, 0,
6884                             "excess elements in array initializer");
6885               break;
6886             }
6887
6888           /* Now output the actual element.  */
6889           if (value.value)
6890             {
6891               push_array_bounds (tree_low_cst (constructor_index, 1));
6892               output_init_element (value.value, strict_string,
6893                                    elttype, constructor_index, 1, implicit);
6894               RESTORE_SPELLING_DEPTH (constructor_depth);
6895             }
6896
6897           constructor_index
6898             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6899
6900           if (!value.value)
6901             /* If we are doing the bookkeeping for an element that was
6902                directly output as a constructor, we must update
6903                constructor_unfilled_index.  */
6904             constructor_unfilled_index = constructor_index;
6905         }
6906       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6907         {
6908           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6909
6910          /* Do a basic check of initializer size.  Note that vectors
6911             always have a fixed size derived from their type.  */
6912           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6913             {
6914               pedwarn_init (input_location, 0,
6915                             "excess elements in vector initializer");
6916               break;
6917             }
6918
6919           /* Now output the actual element.  */
6920           if (value.value)
6921             output_init_element (value.value, strict_string,
6922                                  elttype, constructor_index, 1, implicit);
6923
6924           constructor_index
6925             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6926
6927           if (!value.value)
6928             /* If we are doing the bookkeeping for an element that was
6929                directly output as a constructor, we must update
6930                constructor_unfilled_index.  */
6931             constructor_unfilled_index = constructor_index;
6932         }
6933
6934       /* Handle the sole element allowed in a braced initializer
6935          for a scalar variable.  */
6936       else if (constructor_type != error_mark_node
6937                && constructor_fields == 0)
6938         {
6939           pedwarn_init (input_location, 0,
6940                         "excess elements in scalar initializer");
6941           break;
6942         }
6943       else
6944         {
6945           if (value.value)
6946             output_init_element (value.value, strict_string,
6947                                  constructor_type, NULL_TREE, 1, implicit);
6948           constructor_fields = 0;
6949         }
6950
6951       /* Handle range initializers either at this level or anywhere higher
6952          in the designator stack.  */
6953       if (constructor_range_stack)
6954         {
6955           struct constructor_range_stack *p, *range_stack;
6956           int finish = 0;
6957
6958           range_stack = constructor_range_stack;
6959           constructor_range_stack = 0;
6960           while (constructor_stack != range_stack->stack)
6961             {
6962               gcc_assert (constructor_stack->implicit);
6963               process_init_element (pop_init_level (1), true);
6964             }
6965           for (p = range_stack;
6966                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6967                p = p->prev)
6968             {
6969               gcc_assert (constructor_stack->implicit);
6970               process_init_element (pop_init_level (1), true);
6971             }
6972
6973           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6974           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6975             finish = 1;
6976
6977           while (1)
6978             {
6979               constructor_index = p->index;
6980               constructor_fields = p->fields;
6981               if (finish && p->range_end && p->index == p->range_start)
6982                 {
6983                   finish = 0;
6984                   p->prev = 0;
6985                 }
6986               p = p->next;
6987               if (!p)
6988                 break;
6989               push_init_level (2);
6990               p->stack = constructor_stack;
6991               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6992                 p->index = p->range_start;
6993             }
6994
6995           if (!finish)
6996             constructor_range_stack = range_stack;
6997           continue;
6998         }
6999
7000       break;
7001     }
7002
7003   constructor_range_stack = 0;
7004 }
7005 \f
7006 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
7007    (guaranteed to be 'volatile' or null) and ARGS (represented using
7008    an ASM_EXPR node).  */
7009 tree
7010 build_asm_stmt (tree cv_qualifier, tree args)
7011 {
7012   if (!ASM_VOLATILE_P (args) && cv_qualifier)
7013     ASM_VOLATILE_P (args) = 1;
7014   return add_stmt (args);
7015 }
7016
7017 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
7018    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
7019    SIMPLE indicates whether there was anything at all after the
7020    string in the asm expression -- asm("blah") and asm("blah" : )
7021    are subtly different.  We use a ASM_EXPR node to represent this.  */
7022 tree
7023 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
7024                 bool simple)
7025 {
7026   tree tail;
7027   tree args;
7028   int i;
7029   const char *constraint;
7030   const char **oconstraints;
7031   bool allows_mem, allows_reg, is_inout;
7032   int ninputs, noutputs;
7033
7034   ninputs = list_length (inputs);
7035   noutputs = list_length (outputs);
7036   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7037
7038   string = resolve_asm_operand_names (string, outputs, inputs);
7039
7040   /* Remove output conversions that change the type but not the mode.  */
7041   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7042     {
7043       tree output = TREE_VALUE (tail);
7044
7045       /* ??? Really, this should not be here.  Users should be using a
7046          proper lvalue, dammit.  But there's a long history of using casts
7047          in the output operands.  In cases like longlong.h, this becomes a
7048          primitive form of typechecking -- if the cast can be removed, then
7049          the output operand had a type of the proper width; otherwise we'll
7050          get an error.  Gross, but ...  */
7051       STRIP_NOPS (output);
7052
7053       if (!lvalue_or_else (output, lv_asm))
7054         output = error_mark_node;
7055
7056       if (output != error_mark_node
7057           && (TREE_READONLY (output)
7058               || TYPE_READONLY (TREE_TYPE (output))
7059               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7060                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7061                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7062         readonly_error (output, lv_asm);
7063
7064       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7065       oconstraints[i] = constraint;
7066
7067       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7068                                    &allows_mem, &allows_reg, &is_inout))
7069         {
7070           /* If the operand is going to end up in memory,
7071              mark it addressable.  */
7072           if (!allows_reg && !c_mark_addressable (output))
7073             output = error_mark_node;
7074         }
7075       else
7076         output = error_mark_node;
7077
7078       TREE_VALUE (tail) = output;
7079     }
7080
7081   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7082     {
7083       tree input;
7084
7085       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7086       input = TREE_VALUE (tail);
7087
7088       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7089                                   oconstraints, &allows_mem, &allows_reg))
7090         {
7091           /* If the operand is going to end up in memory,
7092              mark it addressable.  */
7093           if (!allows_reg && allows_mem)
7094             {
7095               /* Strip the nops as we allow this case.  FIXME, this really
7096                  should be rejected or made deprecated.  */
7097               STRIP_NOPS (input);
7098               if (!c_mark_addressable (input))
7099                 input = error_mark_node;
7100           }
7101         }
7102       else
7103         input = error_mark_node;
7104
7105       TREE_VALUE (tail) = input;
7106     }
7107
7108   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7109
7110   /* asm statements without outputs, including simple ones, are treated
7111      as volatile.  */
7112   ASM_INPUT_P (args) = simple;
7113   ASM_VOLATILE_P (args) = (noutputs == 0);
7114
7115   return args;
7116 }
7117 \f
7118 /* Generate a goto statement to LABEL.  */
7119
7120 tree
7121 c_finish_goto_label (tree label)
7122 {
7123   tree decl = lookup_label (label);
7124   if (!decl)
7125     return NULL_TREE;
7126
7127   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7128     {
7129       error ("jump into statement expression");
7130       return NULL_TREE;
7131     }
7132
7133   if (C_DECL_UNJUMPABLE_VM (decl))
7134     {
7135       error ("jump into scope of identifier with variably modified type");
7136       return NULL_TREE;
7137     }
7138
7139   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7140     {
7141       /* No jump from outside this statement expression context, so
7142          record that there is a jump from within this context.  */
7143       struct c_label_list *nlist;
7144       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7145       nlist->next = label_context_stack_se->labels_used;
7146       nlist->label = decl;
7147       label_context_stack_se->labels_used = nlist;
7148     }
7149
7150   if (!C_DECL_UNDEFINABLE_VM (decl))
7151     {
7152       /* No jump from outside this context context of identifiers with
7153          variably modified type, so record that there is a jump from
7154          within this context.  */
7155       struct c_label_list *nlist;
7156       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7157       nlist->next = label_context_stack_vm->labels_used;
7158       nlist->label = decl;
7159       label_context_stack_vm->labels_used = nlist;
7160     }
7161
7162   TREE_USED (decl) = 1;
7163   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7164 }
7165
7166 /* Generate a computed goto statement to EXPR.  */
7167
7168 tree
7169 c_finish_goto_ptr (tree expr)
7170 {
7171   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7172   expr = convert (ptr_type_node, expr);
7173   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7174 }
7175
7176 /* Generate a C `return' statement.  RETVAL is the expression for what
7177    to return, or a null pointer for `return;' with no value.  */
7178
7179 tree
7180 c_finish_return (tree retval)
7181 {
7182   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7183   bool no_warning = false;
7184
7185   if (TREE_THIS_VOLATILE (current_function_decl))
7186     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7187
7188   if (!retval)
7189     {
7190       current_function_returns_null = 1;
7191       if ((warn_return_type || flag_isoc99)
7192           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7193         {
7194           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7195                        "%<return%> with no value, in "
7196                        "function returning non-void");
7197           no_warning = true;
7198         }
7199     }
7200   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7201     {
7202       current_function_returns_null = 1;
7203       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7204         pedwarn (input_location, 0,
7205                  "%<return%> with a value, in function returning void");
7206       else
7207         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7208                  "%<return%> with expression, in function returning void");
7209     }
7210   else
7211     {
7212       tree t = convert_for_assignment (valtype, retval, ic_return,
7213                                        NULL_TREE, NULL_TREE, 0);
7214       tree res = DECL_RESULT (current_function_decl);
7215       tree inner;
7216
7217       current_function_returns_value = 1;
7218       if (t == error_mark_node)
7219         return NULL_TREE;
7220
7221       inner = t = convert (TREE_TYPE (res), t);
7222
7223       /* Strip any conversions, additions, and subtractions, and see if
7224          we are returning the address of a local variable.  Warn if so.  */
7225       while (1)
7226         {
7227           switch (TREE_CODE (inner))
7228             {
7229             CASE_CONVERT:   case NON_LVALUE_EXPR:
7230             case PLUS_EXPR:
7231               inner = TREE_OPERAND (inner, 0);
7232               continue;
7233
7234             case MINUS_EXPR:
7235               /* If the second operand of the MINUS_EXPR has a pointer
7236                  type (or is converted from it), this may be valid, so
7237                  don't give a warning.  */
7238               {
7239                 tree op1 = TREE_OPERAND (inner, 1);
7240
7241                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7242                        && (CONVERT_EXPR_P (op1)
7243                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7244                   op1 = TREE_OPERAND (op1, 0);
7245
7246                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7247                   break;
7248
7249                 inner = TREE_OPERAND (inner, 0);
7250                 continue;
7251               }
7252
7253             case ADDR_EXPR:
7254               inner = TREE_OPERAND (inner, 0);
7255
7256               while (REFERENCE_CLASS_P (inner)
7257                      && TREE_CODE (inner) != INDIRECT_REF)
7258                 inner = TREE_OPERAND (inner, 0);
7259
7260               if (DECL_P (inner)
7261                   && !DECL_EXTERNAL (inner)
7262                   && !TREE_STATIC (inner)
7263                   && DECL_CONTEXT (inner) == current_function_decl)
7264                 warning (0, "function returns address of local variable");
7265               break;
7266
7267             default:
7268               break;
7269             }
7270
7271           break;
7272         }
7273
7274       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7275
7276       if (warn_sequence_point)
7277         verify_sequence_points (retval);
7278     }
7279
7280   ret_stmt = build_stmt (RETURN_EXPR, retval);
7281   TREE_NO_WARNING (ret_stmt) |= no_warning;
7282   return add_stmt (ret_stmt);
7283 }
7284 \f
7285 struct c_switch {
7286   /* The SWITCH_EXPR being built.  */
7287   tree switch_expr;
7288
7289   /* The original type of the testing expression, i.e. before the
7290      default conversion is applied.  */
7291   tree orig_type;
7292
7293   /* A splay-tree mapping the low element of a case range to the high
7294      element, or NULL_TREE if there is no high element.  Used to
7295      determine whether or not a new case label duplicates an old case
7296      label.  We need a tree, rather than simply a hash table, because
7297      of the GNU case range extension.  */
7298   splay_tree cases;
7299
7300   /* Number of nested statement expressions within this switch
7301      statement; if nonzero, case and default labels may not
7302      appear.  */
7303   unsigned int blocked_stmt_expr;
7304
7305   /* Scope of outermost declarations of identifiers with variably
7306      modified type within this switch statement; if nonzero, case and
7307      default labels may not appear.  */
7308   unsigned int blocked_vm;
7309
7310   /* The next node on the stack.  */
7311   struct c_switch *next;
7312 };
7313
7314 /* A stack of the currently active switch statements.  The innermost
7315    switch statement is on the top of the stack.  There is no need to
7316    mark the stack for garbage collection because it is only active
7317    during the processing of the body of a function, and we never
7318    collect at that point.  */
7319
7320 struct c_switch *c_switch_stack;
7321
7322 /* Start a C switch statement, testing expression EXP.  Return the new
7323    SWITCH_EXPR.  */
7324
7325 tree
7326 c_start_case (tree exp)
7327 {
7328   tree orig_type = error_mark_node;
7329   struct c_switch *cs;
7330
7331   if (exp != error_mark_node)
7332     {
7333       orig_type = TREE_TYPE (exp);
7334
7335       if (!INTEGRAL_TYPE_P (orig_type))
7336         {
7337           if (orig_type != error_mark_node)
7338             {
7339               error ("switch quantity not an integer");
7340               orig_type = error_mark_node;
7341             }
7342           exp = integer_zero_node;
7343         }
7344       else
7345         {
7346           tree type = TYPE_MAIN_VARIANT (orig_type);
7347
7348           if (!in_system_header
7349               && (type == long_integer_type_node
7350                   || type == long_unsigned_type_node))
7351             warning (OPT_Wtraditional, "%<long%> switch expression not "
7352                      "converted to %<int%> in ISO C");
7353
7354           exp = default_conversion (exp);
7355
7356           if (warn_sequence_point)
7357             verify_sequence_points (exp);
7358         }
7359     }
7360
7361   /* Add this new SWITCH_EXPR to the stack.  */
7362   cs = XNEW (struct c_switch);
7363   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7364   cs->orig_type = orig_type;
7365   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7366   cs->blocked_stmt_expr = 0;
7367   cs->blocked_vm = 0;
7368   cs->next = c_switch_stack;
7369   c_switch_stack = cs;
7370
7371   return add_stmt (cs->switch_expr);
7372 }
7373
7374 /* Process a case label.  */
7375
7376 tree
7377 do_case (tree low_value, tree high_value)
7378 {
7379   tree label = NULL_TREE;
7380
7381   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7382       && !c_switch_stack->blocked_vm)
7383     {
7384       label = c_add_case_label (c_switch_stack->cases,
7385                                 SWITCH_COND (c_switch_stack->switch_expr),
7386                                 c_switch_stack->orig_type,
7387                                 low_value, high_value);
7388       if (label == error_mark_node)
7389         label = NULL_TREE;
7390     }
7391   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7392     {
7393       if (low_value)
7394         error ("case label in statement expression not containing "
7395                "enclosing switch statement");
7396       else
7397         error ("%<default%> label in statement expression not containing "
7398                "enclosing switch statement");
7399     }
7400   else if (c_switch_stack && c_switch_stack->blocked_vm)
7401     {
7402       if (low_value)
7403         error ("case label in scope of identifier with variably modified "
7404                "type not containing enclosing switch statement");
7405       else
7406         error ("%<default%> label in scope of identifier with variably "
7407                "modified type not containing enclosing switch statement");
7408     }
7409   else if (low_value)
7410     error ("case label not within a switch statement");
7411   else
7412     error ("%<default%> label not within a switch statement");
7413
7414   return label;
7415 }
7416
7417 /* Finish the switch statement.  */
7418
7419 void
7420 c_finish_case (tree body)
7421 {
7422   struct c_switch *cs = c_switch_stack;
7423   location_t switch_location;
7424
7425   SWITCH_BODY (cs->switch_expr) = body;
7426
7427   /* We must not be within a statement expression nested in the switch
7428      at this point; we might, however, be within the scope of an
7429      identifier with variably modified type nested in the switch.  */
7430   gcc_assert (!cs->blocked_stmt_expr);
7431
7432   /* Emit warnings as needed.  */
7433   if (EXPR_HAS_LOCATION (cs->switch_expr))
7434     switch_location = EXPR_LOCATION (cs->switch_expr);
7435   else
7436     switch_location = input_location;
7437   c_do_switch_warnings (cs->cases, switch_location,
7438                         TREE_TYPE (cs->switch_expr),
7439                         SWITCH_COND (cs->switch_expr));
7440
7441   /* Pop the stack.  */
7442   c_switch_stack = cs->next;
7443   splay_tree_delete (cs->cases);
7444   XDELETE (cs);
7445 }
7446 \f
7447 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7448    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7449    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7450    statement, and was not surrounded with parenthesis.  */
7451
7452 void
7453 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7454                   tree else_block, bool nested_if)
7455 {
7456   tree stmt;
7457
7458   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7459   if (warn_parentheses && nested_if && else_block == NULL)
7460     {
7461       tree inner_if = then_block;
7462
7463       /* We know from the grammar productions that there is an IF nested
7464          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7465          it might not be exactly THEN_BLOCK, but should be the last
7466          non-container statement within.  */
7467       while (1)
7468         switch (TREE_CODE (inner_if))
7469           {
7470           case COND_EXPR:
7471             goto found;
7472           case BIND_EXPR:
7473             inner_if = BIND_EXPR_BODY (inner_if);
7474             break;
7475           case STATEMENT_LIST:
7476             inner_if = expr_last (then_block);
7477             break;
7478           case TRY_FINALLY_EXPR:
7479           case TRY_CATCH_EXPR:
7480             inner_if = TREE_OPERAND (inner_if, 0);
7481             break;
7482           default:
7483             gcc_unreachable ();
7484           }
7485     found:
7486
7487       if (COND_EXPR_ELSE (inner_if))
7488          warning (OPT_Wparentheses,
7489                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7490                   &if_locus);
7491     }
7492
7493   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7494   SET_EXPR_LOCATION (stmt, if_locus);
7495   add_stmt (stmt);
7496 }
7497
7498 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7499    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7500    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7501    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7502    the continue label.  Everything is allowed to be NULL.  */
7503
7504 void
7505 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7506                tree blab, tree clab, bool cond_is_first)
7507 {
7508   tree entry = NULL, exit = NULL, t;
7509
7510   /* If the condition is zero don't generate a loop construct.  */
7511   if (cond && integer_zerop (cond))
7512     {
7513       if (cond_is_first)
7514         {
7515           t = build_and_jump (&blab);
7516           SET_EXPR_LOCATION (t, start_locus);
7517           add_stmt (t);
7518         }
7519     }
7520   else
7521     {
7522       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7523
7524       /* If we have an exit condition, then we build an IF with gotos either
7525          out of the loop, or to the top of it.  If there's no exit condition,
7526          then we just build a jump back to the top.  */
7527       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7528
7529       if (cond && !integer_nonzerop (cond))
7530         {
7531           /* Canonicalize the loop condition to the end.  This means
7532              generating a branch to the loop condition.  Reuse the
7533              continue label, if possible.  */
7534           if (cond_is_first)
7535             {
7536               if (incr || !clab)
7537                 {
7538                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7539                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7540                 }
7541               else
7542                 t = build1 (GOTO_EXPR, void_type_node, clab);
7543               SET_EXPR_LOCATION (t, start_locus);
7544               add_stmt (t);
7545             }
7546
7547           t = build_and_jump (&blab);
7548           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7549           if (cond_is_first)
7550             SET_EXPR_LOCATION (exit, start_locus);
7551           else
7552             SET_EXPR_LOCATION (exit, input_location);
7553         }
7554
7555       add_stmt (top);
7556     }
7557
7558   if (body)
7559     add_stmt (body);
7560   if (clab)
7561     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7562   if (incr)
7563     add_stmt (incr);
7564   if (entry)
7565     add_stmt (entry);
7566   if (exit)
7567     add_stmt (exit);
7568   if (blab)
7569     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7570 }
7571
7572 tree
7573 c_finish_bc_stmt (tree *label_p, bool is_break)
7574 {
7575   bool skip;
7576   tree label = *label_p;
7577
7578   /* In switch statements break is sometimes stylistically used after
7579      a return statement.  This can lead to spurious warnings about
7580      control reaching the end of a non-void function when it is
7581      inlined.  Note that we are calling block_may_fallthru with
7582      language specific tree nodes; this works because
7583      block_may_fallthru returns true when given something it does not
7584      understand.  */
7585   skip = !block_may_fallthru (cur_stmt_list);
7586
7587   if (!label)
7588     {
7589       if (!skip)
7590         *label_p = label = create_artificial_label ();
7591     }
7592   else if (TREE_CODE (label) == LABEL_DECL)
7593     ;
7594   else switch (TREE_INT_CST_LOW (label))
7595     {
7596     case 0:
7597       if (is_break)
7598         error ("break statement not within loop or switch");
7599       else
7600         error ("continue statement not within a loop");
7601       return NULL_TREE;
7602
7603     case 1:
7604       gcc_assert (is_break);
7605       error ("break statement used with OpenMP for loop");
7606       return NULL_TREE;
7607
7608     default:
7609       gcc_unreachable ();
7610     }
7611
7612   if (skip)
7613     return NULL_TREE;
7614
7615   if (!is_break)
7616     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7617
7618   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7619 }
7620
7621 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7622
7623 static void
7624 emit_side_effect_warnings (tree expr)
7625 {
7626   if (expr == error_mark_node)
7627     ;
7628   else if (!TREE_SIDE_EFFECTS (expr))
7629     {
7630       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7631         warning (OPT_Wunused_value, "%Hstatement with no effect",
7632                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7633     }
7634   else
7635     warn_if_unused_value (expr, input_location);
7636 }
7637
7638 /* Process an expression as if it were a complete statement.  Emit
7639    diagnostics, but do not call ADD_STMT.  */
7640
7641 tree
7642 c_process_expr_stmt (tree expr)
7643 {
7644   if (!expr)
7645     return NULL_TREE;
7646
7647   if (warn_sequence_point)
7648     verify_sequence_points (expr);
7649
7650   if (TREE_TYPE (expr) != error_mark_node
7651       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7652       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7653     error ("expression statement has incomplete type");
7654
7655   /* If we're not processing a statement expression, warn about unused values.
7656      Warnings for statement expressions will be emitted later, once we figure
7657      out which is the result.  */
7658   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7659       && warn_unused_value)
7660     emit_side_effect_warnings (expr);
7661
7662   /* If the expression is not of a type to which we cannot assign a line
7663      number, wrap the thing in a no-op NOP_EXPR.  */
7664   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7665     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7666
7667   if (CAN_HAVE_LOCATION_P (expr))
7668     SET_EXPR_LOCATION (expr, input_location);
7669
7670   return expr;
7671 }
7672
7673 /* Emit an expression as a statement.  */
7674
7675 tree
7676 c_finish_expr_stmt (tree expr)
7677 {
7678   if (expr)
7679     return add_stmt (c_process_expr_stmt (expr));
7680   else
7681     return NULL;
7682 }
7683
7684 /* Do the opposite and emit a statement as an expression.  To begin,
7685    create a new binding level and return it.  */
7686
7687 tree
7688 c_begin_stmt_expr (void)
7689 {
7690   tree ret;
7691   struct c_label_context_se *nstack;
7692   struct c_label_list *glist;
7693
7694   /* We must force a BLOCK for this level so that, if it is not expanded
7695      later, there is a way to turn off the entire subtree of blocks that
7696      are contained in it.  */
7697   keep_next_level ();
7698   ret = c_begin_compound_stmt (true);
7699   if (c_switch_stack)
7700     {
7701       c_switch_stack->blocked_stmt_expr++;
7702       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7703     }
7704   for (glist = label_context_stack_se->labels_used;
7705        glist != NULL;
7706        glist = glist->next)
7707     {
7708       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7709     }
7710   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7711   nstack->labels_def = NULL;
7712   nstack->labels_used = NULL;
7713   nstack->next = label_context_stack_se;
7714   label_context_stack_se = nstack;
7715
7716   /* Mark the current statement list as belonging to a statement list.  */
7717   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7718
7719   return ret;
7720 }
7721
7722 tree
7723 c_finish_stmt_expr (tree body)
7724 {
7725   tree last, type, tmp, val;
7726   tree *last_p;
7727   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7728
7729   body = c_end_compound_stmt (body, true);
7730   if (c_switch_stack)
7731     {
7732       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7733       c_switch_stack->blocked_stmt_expr--;
7734     }
7735   /* It is no longer possible to jump to labels defined within this
7736      statement expression.  */
7737   for (dlist = label_context_stack_se->labels_def;
7738        dlist != NULL;
7739        dlist = dlist->next)
7740     {
7741       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7742     }
7743   /* It is again possible to define labels with a goto just outside
7744      this statement expression.  */
7745   for (glist = label_context_stack_se->next->labels_used;
7746        glist != NULL;
7747        glist = glist->next)
7748     {
7749       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7750       glist_prev = glist;
7751     }
7752   if (glist_prev != NULL)
7753     glist_prev->next = label_context_stack_se->labels_used;
7754   else
7755     label_context_stack_se->next->labels_used
7756       = label_context_stack_se->labels_used;
7757   label_context_stack_se = label_context_stack_se->next;
7758
7759   /* Locate the last statement in BODY.  See c_end_compound_stmt
7760      about always returning a BIND_EXPR.  */
7761   last_p = &BIND_EXPR_BODY (body);
7762   last = BIND_EXPR_BODY (body);
7763
7764  continue_searching:
7765   if (TREE_CODE (last) == STATEMENT_LIST)
7766     {
7767       tree_stmt_iterator i;
7768
7769       /* This can happen with degenerate cases like ({ }).  No value.  */
7770       if (!TREE_SIDE_EFFECTS (last))
7771         return body;
7772
7773       /* If we're supposed to generate side effects warnings, process
7774          all of the statements except the last.  */
7775       if (warn_unused_value)
7776         {
7777           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7778             emit_side_effect_warnings (tsi_stmt (i));
7779         }
7780       else
7781         i = tsi_last (last);
7782       last_p = tsi_stmt_ptr (i);
7783       last = *last_p;
7784     }
7785
7786   /* If the end of the list is exception related, then the list was split
7787      by a call to push_cleanup.  Continue searching.  */
7788   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7789       || TREE_CODE (last) == TRY_CATCH_EXPR)
7790     {
7791       last_p = &TREE_OPERAND (last, 0);
7792       last = *last_p;
7793       goto continue_searching;
7794     }
7795
7796   /* In the case that the BIND_EXPR is not necessary, return the
7797      expression out from inside it.  */
7798   if (last == error_mark_node
7799       || (last == BIND_EXPR_BODY (body)
7800           && BIND_EXPR_VARS (body) == NULL))
7801     {
7802       /* Do not warn if the return value of a statement expression is
7803          unused.  */
7804       if (CAN_HAVE_LOCATION_P (last))
7805         TREE_NO_WARNING (last) = 1;
7806       return last;
7807     }
7808
7809   /* Extract the type of said expression.  */
7810   type = TREE_TYPE (last);
7811
7812   /* If we're not returning a value at all, then the BIND_EXPR that
7813      we already have is a fine expression to return.  */
7814   if (!type || VOID_TYPE_P (type))
7815     return body;
7816
7817   /* Now that we've located the expression containing the value, it seems
7818      silly to make voidify_wrapper_expr repeat the process.  Create a
7819      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7820   tmp = create_tmp_var_raw (type, NULL);
7821
7822   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7823      tree_expr_nonnegative_p giving up immediately.  */
7824   val = last;
7825   if (TREE_CODE (val) == NOP_EXPR
7826       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7827     val = TREE_OPERAND (val, 0);
7828
7829   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7830   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7831
7832   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7833 }
7834
7835 /* Begin the scope of an identifier of variably modified type, scope
7836    number SCOPE.  Jumping from outside this scope to inside it is not
7837    permitted.  */
7838
7839 void
7840 c_begin_vm_scope (unsigned int scope)
7841 {
7842   struct c_label_context_vm *nstack;
7843   struct c_label_list *glist;
7844
7845   gcc_assert (scope > 0);
7846
7847   /* At file_scope, we don't have to do any processing.  */
7848   if (label_context_stack_vm == NULL)
7849     return;
7850
7851   if (c_switch_stack && !c_switch_stack->blocked_vm)
7852     c_switch_stack->blocked_vm = scope;
7853   for (glist = label_context_stack_vm->labels_used;
7854        glist != NULL;
7855        glist = glist->next)
7856     {
7857       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7858     }
7859   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7860   nstack->labels_def = NULL;
7861   nstack->labels_used = NULL;
7862   nstack->scope = scope;
7863   nstack->next = label_context_stack_vm;
7864   label_context_stack_vm = nstack;
7865 }
7866
7867 /* End a scope which may contain identifiers of variably modified
7868    type, scope number SCOPE.  */
7869
7870 void
7871 c_end_vm_scope (unsigned int scope)
7872 {
7873   if (label_context_stack_vm == NULL)
7874     return;
7875   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7876     c_switch_stack->blocked_vm = 0;
7877   /* We may have a number of nested scopes of identifiers with
7878      variably modified type, all at this depth.  Pop each in turn.  */
7879   while (label_context_stack_vm->scope == scope)
7880     {
7881       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7882
7883       /* It is no longer possible to jump to labels defined within this
7884          scope.  */
7885       for (dlist = label_context_stack_vm->labels_def;
7886            dlist != NULL;
7887            dlist = dlist->next)
7888         {
7889           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7890         }
7891       /* It is again possible to define labels with a goto just outside
7892          this scope.  */
7893       for (glist = label_context_stack_vm->next->labels_used;
7894            glist != NULL;
7895            glist = glist->next)
7896         {
7897           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7898           glist_prev = glist;
7899         }
7900       if (glist_prev != NULL)
7901         glist_prev->next = label_context_stack_vm->labels_used;
7902       else
7903         label_context_stack_vm->next->labels_used
7904           = label_context_stack_vm->labels_used;
7905       label_context_stack_vm = label_context_stack_vm->next;
7906     }
7907 }
7908 \f
7909 /* Begin and end compound statements.  This is as simple as pushing
7910    and popping new statement lists from the tree.  */
7911
7912 tree
7913 c_begin_compound_stmt (bool do_scope)
7914 {
7915   tree stmt = push_stmt_list ();
7916   if (do_scope)
7917     push_scope ();
7918   return stmt;
7919 }
7920
7921 tree
7922 c_end_compound_stmt (tree stmt, bool do_scope)
7923 {
7924   tree block = NULL;
7925
7926   if (do_scope)
7927     {
7928       if (c_dialect_objc ())
7929         objc_clear_super_receiver ();
7930       block = pop_scope ();
7931     }
7932
7933   stmt = pop_stmt_list (stmt);
7934   stmt = c_build_bind_expr (block, stmt);
7935
7936   /* If this compound statement is nested immediately inside a statement
7937      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7938      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7939      STATEMENT_LISTs merge, and thus we can lose track of what statement
7940      was really last.  */
7941   if (cur_stmt_list
7942       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7943       && TREE_CODE (stmt) != BIND_EXPR)
7944     {
7945       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7946       TREE_SIDE_EFFECTS (stmt) = 1;
7947     }
7948
7949   return stmt;
7950 }
7951
7952 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7953    when the current scope is exited.  EH_ONLY is true when this is not
7954    meant to apply to normal control flow transfer.  */
7955
7956 void
7957 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7958 {
7959   enum tree_code code;
7960   tree stmt, list;
7961   bool stmt_expr;
7962
7963   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7964   stmt = build_stmt (code, NULL, cleanup);
7965   add_stmt (stmt);
7966   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7967   list = push_stmt_list ();
7968   TREE_OPERAND (stmt, 0) = list;
7969   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7970 }
7971 \f
7972 /* Build a binary-operation expression without default conversions.
7973    CODE is the kind of expression to build.
7974    LOCATION is the operator's location.
7975    This function differs from `build' in several ways:
7976    the data type of the result is computed and recorded in it,
7977    warnings are generated if arg data types are invalid,
7978    special handling for addition and subtraction of pointers is known,
7979    and some optimization is done (operations on narrow ints
7980    are done in the narrower type when that gives the same result).
7981    Constant folding is also done before the result is returned.
7982
7983    Note that the operands will never have enumeral types, or function
7984    or array types, because either they will have the default conversions
7985    performed or they have both just been converted to some other type in which
7986    the arithmetic is to be done.  */
7987
7988 tree
7989 build_binary_op (location_t location, enum tree_code code,
7990                  tree orig_op0, tree orig_op1, int convert_p)
7991 {
7992   tree type0, type1;
7993   enum tree_code code0, code1;
7994   tree op0, op1;
7995   tree ret = error_mark_node;
7996   const char *invalid_op_diag;
7997
7998   /* Expression code to give to the expression when it is built.
7999      Normally this is CODE, which is what the caller asked for,
8000      but in some special cases we change it.  */
8001   enum tree_code resultcode = code;
8002
8003   /* Data type in which the computation is to be performed.
8004      In the simplest cases this is the common type of the arguments.  */
8005   tree result_type = NULL;
8006
8007   /* Nonzero means operands have already been type-converted
8008      in whatever way is necessary.
8009      Zero means they need to be converted to RESULT_TYPE.  */
8010   int converted = 0;
8011
8012   /* Nonzero means create the expression with this type, rather than
8013      RESULT_TYPE.  */
8014   tree build_type = 0;
8015
8016   /* Nonzero means after finally constructing the expression
8017      convert it to this type.  */
8018   tree final_type = 0;
8019
8020   /* Nonzero if this is an operation like MIN or MAX which can
8021      safely be computed in short if both args are promoted shorts.
8022      Also implies COMMON.
8023      -1 indicates a bitwise operation; this makes a difference
8024      in the exact conditions for when it is safe to do the operation
8025      in a narrower mode.  */
8026   int shorten = 0;
8027
8028   /* Nonzero if this is a comparison operation;
8029      if both args are promoted shorts, compare the original shorts.
8030      Also implies COMMON.  */
8031   int short_compare = 0;
8032
8033   /* Nonzero if this is a right-shift operation, which can be computed on the
8034      original short and then promoted if the operand is a promoted short.  */
8035   int short_shift = 0;
8036
8037   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8038   int common = 0;
8039
8040   /* True means types are compatible as far as ObjC is concerned.  */
8041   bool objc_ok;
8042
8043   if (location == UNKNOWN_LOCATION)
8044     location = input_location;
8045
8046   if (convert_p)
8047     {
8048       op0 = default_conversion (orig_op0);
8049       op1 = default_conversion (orig_op1);
8050     }
8051   else
8052     {
8053       op0 = orig_op0;
8054       op1 = orig_op1;
8055     }
8056
8057   type0 = TREE_TYPE (op0);
8058   type1 = TREE_TYPE (op1);
8059
8060   /* The expression codes of the data types of the arguments tell us
8061      whether the arguments are integers, floating, pointers, etc.  */
8062   code0 = TREE_CODE (type0);
8063   code1 = TREE_CODE (type1);
8064
8065   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8066   STRIP_TYPE_NOPS (op0);
8067   STRIP_TYPE_NOPS (op1);
8068
8069   /* If an error was already reported for one of the arguments,
8070      avoid reporting another error.  */
8071
8072   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8073     return error_mark_node;
8074
8075   if ((invalid_op_diag
8076        = targetm.invalid_binary_op (code, type0, type1)))
8077     {
8078       error_at (location, invalid_op_diag);
8079       return error_mark_node;
8080     }
8081
8082   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8083
8084   switch (code)
8085     {
8086     case PLUS_EXPR:
8087       /* Handle the pointer + int case.  */
8088       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8089         {
8090           ret = pointer_int_sum (PLUS_EXPR, op0, op1);
8091           goto return_build_binary_op;
8092         }
8093       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8094         {
8095           ret = pointer_int_sum (PLUS_EXPR, op1, op0);
8096           goto return_build_binary_op;
8097         }
8098       else
8099         common = 1;
8100       break;
8101
8102     case MINUS_EXPR:
8103       /* Subtraction of two similar pointers.
8104          We must subtract them as integers, then divide by object size.  */
8105       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8106           && comp_target_types (type0, type1))
8107         {
8108           ret = pointer_diff (op0, op1);
8109           goto return_build_binary_op;
8110         }
8111       /* Handle pointer minus int.  Just like pointer plus int.  */
8112       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8113         {
8114           ret = pointer_int_sum (MINUS_EXPR, op0, op1);
8115           goto return_build_binary_op;
8116         }
8117       else
8118         common = 1;
8119       break;
8120
8121     case MULT_EXPR:
8122       common = 1;
8123       break;
8124
8125     case TRUNC_DIV_EXPR:
8126     case CEIL_DIV_EXPR:
8127     case FLOOR_DIV_EXPR:
8128     case ROUND_DIV_EXPR:
8129     case EXACT_DIV_EXPR:
8130       warn_for_div_by_zero (location, op1);
8131
8132       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8133            || code0 == FIXED_POINT_TYPE
8134            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8135           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8136               || code1 == FIXED_POINT_TYPE
8137               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8138         {
8139           enum tree_code tcode0 = code0, tcode1 = code1;
8140
8141           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8142             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8143           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8144             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8145
8146           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8147               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8148             resultcode = RDIV_EXPR;
8149           else
8150             /* Although it would be tempting to shorten always here, that
8151                loses on some targets, since the modulo instruction is
8152                undefined if the quotient can't be represented in the
8153                computation mode.  We shorten only if unsigned or if
8154                dividing by something we know != -1.  */
8155             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8156                        || (TREE_CODE (op1) == INTEGER_CST
8157                            && !integer_all_onesp (op1)));
8158           common = 1;
8159         }
8160       break;
8161
8162     case BIT_AND_EXPR:
8163     case BIT_IOR_EXPR:
8164     case BIT_XOR_EXPR:
8165       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8166         shorten = -1;
8167       /* Allow vector types which are not floating point types.   */
8168       else if (code0 == VECTOR_TYPE
8169                && code1 == VECTOR_TYPE
8170                && !VECTOR_FLOAT_TYPE_P (type0)
8171                && !VECTOR_FLOAT_TYPE_P (type1))
8172         common = 1;
8173       break;
8174
8175     case TRUNC_MOD_EXPR:
8176     case FLOOR_MOD_EXPR:
8177       warn_for_div_by_zero (location, op1);
8178
8179       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8180         {
8181           /* Although it would be tempting to shorten always here, that loses
8182              on some targets, since the modulo instruction is undefined if the
8183              quotient can't be represented in the computation mode.  We shorten
8184              only if unsigned or if dividing by something we know != -1.  */
8185           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8186                      || (TREE_CODE (op1) == INTEGER_CST
8187                          && !integer_all_onesp (op1)));
8188           common = 1;
8189         }
8190       break;
8191
8192     case TRUTH_ANDIF_EXPR:
8193     case TRUTH_ORIF_EXPR:
8194     case TRUTH_AND_EXPR:
8195     case TRUTH_OR_EXPR:
8196     case TRUTH_XOR_EXPR:
8197       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8198            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8199            || code0 == FIXED_POINT_TYPE)
8200           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8201               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8202               || code1 == FIXED_POINT_TYPE))
8203         {
8204           /* Result of these operations is always an int,
8205              but that does not mean the operands should be
8206              converted to ints!  */
8207           result_type = integer_type_node;
8208           op0 = c_common_truthvalue_conversion (location, op0);
8209           op1 = c_common_truthvalue_conversion (location, op1);
8210           converted = 1;
8211         }
8212       break;
8213
8214       /* Shift operations: result has same type as first operand;
8215          always convert second operand to int.
8216          Also set SHORT_SHIFT if shifting rightward.  */
8217
8218     case RSHIFT_EXPR:
8219       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8220           && code1 == INTEGER_TYPE)
8221         {
8222           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8223             {
8224               if (tree_int_cst_sgn (op1) < 0)
8225                 warning (0, "right shift count is negative");
8226               else
8227                 {
8228                   if (!integer_zerop (op1))
8229                     short_shift = 1;
8230
8231                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8232                     warning (0, "right shift count >= width of type");
8233                 }
8234             }
8235
8236           /* Use the type of the value to be shifted.  */
8237           result_type = type0;
8238           /* Convert the shift-count to an integer, regardless of size
8239              of value being shifted.  */
8240           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8241             op1 = convert (integer_type_node, op1);
8242           /* Avoid converting op1 to result_type later.  */
8243           converted = 1;
8244         }
8245       break;
8246
8247     case LSHIFT_EXPR:
8248       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8249           && code1 == INTEGER_TYPE)
8250         {
8251           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8252             {
8253               if (tree_int_cst_sgn (op1) < 0)
8254                 warning (0, "left shift count is negative");
8255
8256               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8257                 warning (0, "left shift count >= width of type");
8258             }
8259
8260           /* Use the type of the value to be shifted.  */
8261           result_type = type0;
8262           /* Convert the shift-count to an integer, regardless of size
8263              of value being shifted.  */
8264           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8265             op1 = convert (integer_type_node, op1);
8266           /* Avoid converting op1 to result_type later.  */
8267           converted = 1;
8268         }
8269       break;
8270
8271     case EQ_EXPR:
8272     case NE_EXPR:
8273       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8274         warning_at (location,
8275                     OPT_Wfloat_equal,
8276                     "comparing floating point with == or != is unsafe");
8277       /* Result of comparison is always int,
8278          but don't convert the args to int!  */
8279       build_type = integer_type_node;
8280       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8281            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8282           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8283               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8284         short_compare = 1;
8285       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8286         {
8287           tree tt0 = TREE_TYPE (type0);
8288           tree tt1 = TREE_TYPE (type1);
8289           /* Anything compares with void *.  void * compares with anything.
8290              Otherwise, the targets must be compatible
8291              and both must be object or both incomplete.  */
8292           if (comp_target_types (type0, type1))
8293             result_type = common_pointer_type (type0, type1);
8294           else if (VOID_TYPE_P (tt0))
8295             {
8296               /* op0 != orig_op0 detects the case of something
8297                  whose value is 0 but which isn't a valid null ptr const.  */
8298               if (pedantic && !null_pointer_constant_p (orig_op0)
8299                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8300                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8301                          "comparison of %<void *%> with function pointer");
8302             }
8303           else if (VOID_TYPE_P (tt1))
8304             {
8305               if (pedantic && !null_pointer_constant_p (orig_op1)
8306                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8307                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8308                          "comparison of %<void *%> with function pointer");
8309             }
8310           else
8311             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8312             if (!objc_ok)
8313               pedwarn (location, 0,
8314                        "comparison of distinct pointer types lacks a cast");
8315
8316           if (result_type == NULL_TREE)
8317             result_type = ptr_type_node;
8318         }
8319       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8320         {
8321           if (TREE_CODE (op0) == ADDR_EXPR
8322               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8323             warning_at (location,
8324                         OPT_Waddress, "the address of %qD will never be NULL",
8325                         TREE_OPERAND (op0, 0));
8326           result_type = type0;
8327         }
8328       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8329         {
8330           if (TREE_CODE (op1) == ADDR_EXPR
8331               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8332             warning_at (location,
8333                         OPT_Waddress, "the address of %qD will never be NULL",
8334                         TREE_OPERAND (op1, 0));
8335           result_type = type1;
8336         }
8337       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8338         {
8339           result_type = type0;
8340           pedwarn (location, 0, "comparison between pointer and integer");
8341         }
8342       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8343         {
8344           result_type = type1;
8345           pedwarn (location, 0, "comparison between pointer and integer");
8346         }
8347       break;
8348
8349     case LE_EXPR:
8350     case GE_EXPR:
8351     case LT_EXPR:
8352     case GT_EXPR:
8353       build_type = integer_type_node;
8354       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8355            || code0 == FIXED_POINT_TYPE)
8356           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8357               || code1 == FIXED_POINT_TYPE))
8358         short_compare = 1;
8359       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8360         {
8361           if (comp_target_types (type0, type1))
8362             {
8363               result_type = common_pointer_type (type0, type1);
8364               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8365                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8366                 pedwarn (location, 0,
8367                          "comparison of complete and incomplete pointers");
8368               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8369                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8370                          "ordered comparisons of pointers to functions");
8371             }
8372           else
8373             {
8374               result_type = ptr_type_node;
8375               pedwarn (location, 0,
8376                        "comparison of distinct pointer types lacks a cast");
8377             }
8378         }
8379       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8380         {
8381           result_type = type0;
8382           if (pedantic)
8383             pedwarn (location, OPT_pedantic,
8384                      "ordered comparison of pointer with integer zero");
8385           else if (extra_warnings)
8386             warning_at (location, OPT_Wextra,
8387                      "ordered comparison of pointer with integer zero");
8388         }
8389       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8390         {
8391           result_type = type1;
8392           pedwarn (location, OPT_pedantic,
8393                    "ordered comparison of pointer with integer zero");
8394         }
8395       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8396         {
8397           result_type = type0;
8398           pedwarn (location, 0, "comparison between pointer and integer");
8399         }
8400       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8401         {
8402           result_type = type1;
8403           pedwarn (location, 0, "comparison between pointer and integer");
8404         }
8405       break;
8406
8407     default:
8408       gcc_unreachable ();
8409     }
8410
8411   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8412     return error_mark_node;
8413
8414   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8415       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8416           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8417                                                     TREE_TYPE (type1))))
8418     {
8419       binary_op_error (location, code, type0, type1);
8420       return error_mark_node;
8421     }
8422
8423   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8424        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8425       &&
8426       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8427        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8428     {
8429       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8430
8431       if (shorten || common || short_compare)
8432         {
8433           result_type = c_common_type (type0, type1);
8434           if (result_type == error_mark_node)
8435             return error_mark_node;
8436         }
8437
8438       /* For certain operations (which identify themselves by shorten != 0)
8439          if both args were extended from the same smaller type,
8440          do the arithmetic in that type and then extend.
8441
8442          shorten !=0 and !=1 indicates a bitwise operation.
8443          For them, this optimization is safe only if
8444          both args are zero-extended or both are sign-extended.
8445          Otherwise, we might change the result.
8446          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8447          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8448
8449       if (shorten && none_complex)
8450         {
8451           final_type = result_type;
8452           result_type = shorten_binary_op (result_type, op0, op1,
8453                                            shorten == -1);
8454         }
8455
8456       /* Shifts can be shortened if shifting right.  */
8457
8458       if (short_shift)
8459         {
8460           int unsigned_arg;
8461           tree arg0 = get_narrower (op0, &unsigned_arg);
8462
8463           final_type = result_type;
8464
8465           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8466             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8467
8468           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8469               /* We can shorten only if the shift count is less than the
8470                  number of bits in the smaller type size.  */
8471               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8472               /* We cannot drop an unsigned shift after sign-extension.  */
8473               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8474             {
8475               /* Do an unsigned shift if the operand was zero-extended.  */
8476               result_type
8477                 = c_common_signed_or_unsigned_type (unsigned_arg,
8478                                                     TREE_TYPE (arg0));
8479               /* Convert value-to-be-shifted to that type.  */
8480               if (TREE_TYPE (op0) != result_type)
8481                 op0 = convert (result_type, op0);
8482               converted = 1;
8483             }
8484         }
8485
8486       /* Comparison operations are shortened too but differently.
8487          They identify themselves by setting short_compare = 1.  */
8488
8489       if (short_compare)
8490         {
8491           /* Don't write &op0, etc., because that would prevent op0
8492              from being kept in a register.
8493              Instead, make copies of the our local variables and
8494              pass the copies by reference, then copy them back afterward.  */
8495           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8496           enum tree_code xresultcode = resultcode;
8497           tree val
8498             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8499
8500           if (val != 0)
8501             {
8502               ret = val;
8503               goto return_build_binary_op;
8504             }
8505
8506           op0 = xop0, op1 = xop1;
8507           converted = 1;
8508           resultcode = xresultcode;
8509
8510           if (warn_sign_compare && !skip_evaluation)
8511             {
8512               warn_for_sign_compare (location, orig_op0, orig_op1, op0, op1,
8513                                      result_type, resultcode);
8514             }
8515         }
8516     }
8517
8518   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8519      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8520      Then the expression will be built.
8521      It will be given type FINAL_TYPE if that is nonzero;
8522      otherwise, it will be given type RESULT_TYPE.  */
8523
8524   if (!result_type)
8525     {
8526       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
8527       return error_mark_node;
8528     }
8529
8530   if (!converted)
8531     {
8532       if (TREE_TYPE (op0) != result_type)
8533         op0 = convert_and_check (result_type, op0);
8534       if (TREE_TYPE (op1) != result_type)
8535         op1 = convert_and_check (result_type, op1);
8536
8537       /* This can happen if one operand has a vector type, and the other
8538          has a different type.  */
8539       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8540         return error_mark_node;
8541     }
8542
8543   if (build_type == NULL_TREE)
8544     build_type = result_type;
8545
8546   /* Treat expressions in initializers specially as they can't trap.  */
8547   ret = require_constant_value ? fold_build2_initializer (resultcode,
8548                                                           build_type,
8549                                                           op0, op1)
8550                                : fold_build2 (resultcode, build_type,
8551                                               op0, op1);
8552   if (final_type != 0)
8553     ret = convert (final_type, ret);
8554
8555  return_build_binary_op:
8556   gcc_assert (ret != error_mark_node);
8557   protected_set_expr_location (ret, location);
8558   return ret;
8559 }
8560
8561
8562 /* Convert EXPR to be a truth-value, validating its type for this
8563    purpose.  LOCATION is the source location for the expression.  */
8564
8565 tree
8566 c_objc_common_truthvalue_conversion (location_t location, tree expr)
8567 {
8568   switch (TREE_CODE (TREE_TYPE (expr)))
8569     {
8570     case ARRAY_TYPE:
8571       error_at (location, "used array that cannot be converted to pointer where scalar is required");
8572       return error_mark_node;
8573
8574     case RECORD_TYPE:
8575       error_at (location, "used struct type value where scalar is required");
8576       return error_mark_node;
8577
8578     case UNION_TYPE:
8579       error_at (location, "used union type value where scalar is required");
8580       return error_mark_node;
8581
8582     case FUNCTION_TYPE:
8583       gcc_unreachable ();
8584
8585     default:
8586       break;
8587     }
8588
8589   /* ??? Should we also give an error for void and vectors rather than
8590      leaving those to give errors later?  */
8591   return c_common_truthvalue_conversion (location, expr);
8592 }
8593 \f
8594
8595 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8596    required.  */
8597
8598 tree
8599 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8600 {
8601   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8602     {
8603       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8604       /* Executing a compound literal inside a function reinitializes
8605          it.  */
8606       if (!TREE_STATIC (decl))
8607         *se = true;
8608       return decl;
8609     }
8610   else
8611     return expr;
8612 }
8613 \f
8614 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8615
8616 tree
8617 c_begin_omp_parallel (void)
8618 {
8619   tree block;
8620
8621   keep_next_level ();
8622   block = c_begin_compound_stmt (true);
8623
8624   return block;
8625 }
8626
8627 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8628
8629 tree
8630 c_finish_omp_parallel (tree clauses, tree block)
8631 {
8632   tree stmt;
8633
8634   block = c_end_compound_stmt (block, true);
8635
8636   stmt = make_node (OMP_PARALLEL);
8637   TREE_TYPE (stmt) = void_type_node;
8638   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8639   OMP_PARALLEL_BODY (stmt) = block;
8640
8641   return add_stmt (stmt);
8642 }
8643
8644 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8645
8646 tree
8647 c_begin_omp_task (void)
8648 {
8649   tree block;
8650
8651   keep_next_level ();
8652   block = c_begin_compound_stmt (true);
8653
8654   return block;
8655 }
8656
8657 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8658
8659 tree
8660 c_finish_omp_task (tree clauses, tree block)
8661 {
8662   tree stmt;
8663
8664   block = c_end_compound_stmt (block, true);
8665
8666   stmt = make_node (OMP_TASK);
8667   TREE_TYPE (stmt) = void_type_node;
8668   OMP_TASK_CLAUSES (stmt) = clauses;
8669   OMP_TASK_BODY (stmt) = block;
8670
8671   return add_stmt (stmt);
8672 }
8673
8674 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8675    Remove any elements from the list that are invalid.  */
8676
8677 tree
8678 c_finish_omp_clauses (tree clauses)
8679 {
8680   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8681   tree c, t, *pc = &clauses;
8682   const char *name;
8683
8684   bitmap_obstack_initialize (NULL);
8685   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8686   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8687   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8688
8689   for (pc = &clauses, c = clauses; c ; c = *pc)
8690     {
8691       bool remove = false;
8692       bool need_complete = false;
8693       bool need_implicitly_determined = false;
8694
8695       switch (OMP_CLAUSE_CODE (c))
8696         {
8697         case OMP_CLAUSE_SHARED:
8698           name = "shared";
8699           need_implicitly_determined = true;
8700           goto check_dup_generic;
8701
8702         case OMP_CLAUSE_PRIVATE:
8703           name = "private";
8704           need_complete = true;
8705           need_implicitly_determined = true;
8706           goto check_dup_generic;
8707
8708         case OMP_CLAUSE_REDUCTION:
8709           name = "reduction";
8710           need_implicitly_determined = true;
8711           t = OMP_CLAUSE_DECL (c);
8712           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8713               || POINTER_TYPE_P (TREE_TYPE (t)))
8714             {
8715               error ("%qE has invalid type for %<reduction%>", t);
8716               remove = true;
8717             }
8718           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8719             {
8720               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8721               const char *r_name = NULL;
8722
8723               switch (r_code)
8724                 {
8725                 case PLUS_EXPR:
8726                 case MULT_EXPR:
8727                 case MINUS_EXPR:
8728                   break;
8729                 case BIT_AND_EXPR:
8730                   r_name = "&";
8731                   break;
8732                 case BIT_XOR_EXPR:
8733                   r_name = "^";
8734                   break;
8735                 case BIT_IOR_EXPR:
8736                   r_name = "|";
8737                   break;
8738                 case TRUTH_ANDIF_EXPR:
8739                   r_name = "&&";
8740                   break;
8741                 case TRUTH_ORIF_EXPR:
8742                   r_name = "||";
8743                   break;
8744                 default:
8745                   gcc_unreachable ();
8746                 }
8747               if (r_name)
8748                 {
8749                   error ("%qE has invalid type for %<reduction(%s)%>",
8750                          t, r_name);
8751                   remove = true;
8752                 }
8753             }
8754           goto check_dup_generic;
8755
8756         case OMP_CLAUSE_COPYPRIVATE:
8757           name = "copyprivate";
8758           goto check_dup_generic;
8759
8760         case OMP_CLAUSE_COPYIN:
8761           name = "copyin";
8762           t = OMP_CLAUSE_DECL (c);
8763           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8764             {
8765               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8766               remove = true;
8767             }
8768           goto check_dup_generic;
8769
8770         check_dup_generic:
8771           t = OMP_CLAUSE_DECL (c);
8772           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8773             {
8774               error ("%qE is not a variable in clause %qs", t, name);
8775               remove = true;
8776             }
8777           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8778                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8779                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8780             {
8781               error ("%qE appears more than once in data clauses", t);
8782               remove = true;
8783             }
8784           else
8785             bitmap_set_bit (&generic_head, DECL_UID (t));
8786           break;
8787
8788         case OMP_CLAUSE_FIRSTPRIVATE:
8789           name = "firstprivate";
8790           t = OMP_CLAUSE_DECL (c);
8791           need_complete = true;
8792           need_implicitly_determined = true;
8793           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8794             {
8795               error ("%qE is not a variable in clause %<firstprivate%>", t);
8796               remove = true;
8797             }
8798           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8799                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8800             {
8801               error ("%qE appears more than once in data clauses", t);
8802               remove = true;
8803             }
8804           else
8805             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8806           break;
8807
8808         case OMP_CLAUSE_LASTPRIVATE:
8809           name = "lastprivate";
8810           t = OMP_CLAUSE_DECL (c);
8811           need_complete = true;
8812           need_implicitly_determined = true;
8813           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8814             {
8815               error ("%qE is not a variable in clause %<lastprivate%>", t);
8816               remove = true;
8817             }
8818           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8819                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8820             {
8821               error ("%qE appears more than once in data clauses", t);
8822               remove = true;
8823             }
8824           else
8825             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8826           break;
8827
8828         case OMP_CLAUSE_IF:
8829         case OMP_CLAUSE_NUM_THREADS:
8830         case OMP_CLAUSE_SCHEDULE:
8831         case OMP_CLAUSE_NOWAIT:
8832         case OMP_CLAUSE_ORDERED:
8833         case OMP_CLAUSE_DEFAULT:
8834         case OMP_CLAUSE_UNTIED:
8835         case OMP_CLAUSE_COLLAPSE:
8836           pc = &OMP_CLAUSE_CHAIN (c);
8837           continue;
8838
8839         default:
8840           gcc_unreachable ();
8841         }
8842
8843       if (!remove)
8844         {
8845           t = OMP_CLAUSE_DECL (c);
8846
8847           if (need_complete)
8848             {
8849               t = require_complete_type (t);
8850               if (t == error_mark_node)
8851                 remove = true;
8852             }
8853
8854           if (need_implicitly_determined)
8855             {
8856               const char *share_name = NULL;
8857
8858               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8859                 share_name = "threadprivate";
8860               else switch (c_omp_predetermined_sharing (t))
8861                 {
8862                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8863                   break;
8864                 case OMP_CLAUSE_DEFAULT_SHARED:
8865                   share_name = "shared";
8866                   break;
8867                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8868                   share_name = "private";
8869                   break;
8870                 default:
8871                   gcc_unreachable ();
8872                 }
8873               if (share_name)
8874                 {
8875                   error ("%qE is predetermined %qs for %qs",
8876                          t, share_name, name);
8877                   remove = true;
8878                 }
8879             }
8880         }
8881
8882       if (remove)
8883         *pc = OMP_CLAUSE_CHAIN (c);
8884       else
8885         pc = &OMP_CLAUSE_CHAIN (c);
8886     }
8887
8888   bitmap_obstack_release (NULL);
8889   return clauses;
8890 }
8891
8892 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8893    down to the element type of an array.  */
8894
8895 tree
8896 c_build_qualified_type (tree type, int type_quals)
8897 {
8898   if (type == error_mark_node)
8899     return type;
8900
8901   if (TREE_CODE (type) == ARRAY_TYPE)
8902     {
8903       tree t;
8904       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8905                                                   type_quals);
8906
8907       /* See if we already have an identically qualified type.  */
8908       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8909         {
8910           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8911               && TYPE_NAME (t) == TYPE_NAME (type)
8912               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8913               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8914                                        TYPE_ATTRIBUTES (type)))
8915             break;
8916         }
8917       if (!t)
8918         {
8919           tree domain = TYPE_DOMAIN (type);
8920
8921           t = build_variant_type_copy (type);
8922           TREE_TYPE (t) = element_type;
8923
8924           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8925               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8926             SET_TYPE_STRUCTURAL_EQUALITY (t);
8927           else if (TYPE_CANONICAL (element_type) != element_type
8928                    || (domain && TYPE_CANONICAL (domain) != domain))
8929             {
8930               tree unqualified_canon
8931                 = build_array_type (TYPE_CANONICAL (element_type),
8932                                     domain? TYPE_CANONICAL (domain)
8933                                           : NULL_TREE);
8934               TYPE_CANONICAL (t)
8935                 = c_build_qualified_type (unqualified_canon, type_quals);
8936             }
8937           else
8938             TYPE_CANONICAL (t) = t;
8939         }
8940       return t;
8941     }
8942
8943   /* A restrict-qualified pointer type must be a pointer to object or
8944      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8945      REFERENCE_TYPEs, which is appropriate for C++.  */
8946   if ((type_quals & TYPE_QUAL_RESTRICT)
8947       && (!POINTER_TYPE_P (type)
8948           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8949     {
8950       error ("invalid use of %<restrict%>");
8951       type_quals &= ~TYPE_QUAL_RESTRICT;
8952     }
8953
8954   return build_qualified_type (type, type_quals);
8955 }