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
   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 "tree-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_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static bool null_pointer_constant_p (const_tree);
  78 static tree qualify_type (tree, tree);
  79 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  80 static int comp_target_types (tree, tree);
  81 static int function_types_compatible_p (const_tree, const_tree);
  82 static int type_lists_compatible_p (const_tree, const_tree);
  83 static tree decl_constant_value_for_broken_optimization (tree);
  84 static tree lookup_field (tree, tree);
  85 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  86 static tree pointer_diff (tree, tree);
  87 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  88                                     int);
  89 static tree valid_compound_expr_initializer (tree, tree);
  90 static void push_string (const char *);
  91 static void push_member_name (tree);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (const_tree, enum lvalue_use);
 106 static int lvalue_p (const_tree);
 107 static void record_maybe_used_decl (tree);
 108 static int comptypes_internal (const_tree, const_tree);
 109 \f
 110 /* Return true if EXP is a null pointer constant, false otherwise.  */
 111
 112 static bool
 113 null_pointer_constant_p (const_tree expr)
 114 {
 115   /* This should really operate on c_expr structures, but they aren't
 116      yet available everywhere required.  */
 117   tree type = TREE_TYPE (expr);
 118   return (TREE_CODE (expr) == INTEGER_CST
 119           && !TREE_OVERFLOW (expr)
 120           && integer_zerop (expr)
 121           && (INTEGRAL_TYPE_P (type)
 122               || (TREE_CODE (type) == POINTER_TYPE
 123                   && VOID_TYPE_P (TREE_TYPE (type))
 124                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 125 }
 126 \f/* This is a cache to hold if two types are compatible or not.  */
 127
 128 struct tagged_tu_seen_cache {
 129   const struct tagged_tu_seen_cache * next;
 130   const_tree t1;
 131   const_tree t2;
 132   /* The return value of tagged_types_tu_compatible_p if we had seen
 133      these two types already.  */
 134   int val;
 135 };
 136
 137 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 138 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 139
 140 /* Do `exp = require_complete_type (exp);' to make sure exp
 141    does not have an incomplete type.  (That includes void types.)  */
 142
 143 tree
 144 require_complete_type (tree value)
 145 {
 146   tree type = TREE_TYPE (value);
 147
 148   if (value == error_mark_node || type == error_mark_node)
 149     return error_mark_node;
 150
 151   /* First, detect a valid value with a complete type.  */
 152   if (COMPLETE_TYPE_P (type))
 153     return value;
 154
 155   c_incomplete_type_error (value, type);
 156   return error_mark_node;
 157 }
 158
 159 /* Print an error message for invalid use of an incomplete type.
 160    VALUE is the expression that was used (or 0 if that isn't known)
 161    and TYPE is the type that was invalid.  */
 162
 163 void
 164 c_incomplete_type_error (const_tree value, const_tree type)
 165 {
 166   const char *type_code_string;
 167
 168   /* Avoid duplicate error message.  */
 169   if (TREE_CODE (type) == ERROR_MARK)
 170     return;
 171
 172   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 173                      || TREE_CODE (value) == PARM_DECL))
 174     error ("%qD has an incomplete type", value);
 175   else
 176     {
 177     retry:
 178       /* We must print an error message.  Be clever about what it says.  */
 179
 180       switch (TREE_CODE (type))
 181         {
 182         case RECORD_TYPE:
 183           type_code_string = "struct";
 184           break;
 185
 186         case UNION_TYPE:
 187           type_code_string = "union";
 188           break;
 189
 190         case ENUMERAL_TYPE:
 191           type_code_string = "enum";
 192           break;
 193
 194         case VOID_TYPE:
 195           error ("invalid use of void expression");
 196           return;
 197
 198         case ARRAY_TYPE:
 199           if (TYPE_DOMAIN (type))
 200             {
 201               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 202                 {
 203                   error ("invalid use of flexible array member");
 204                   return;
 205                 }
 206               type = TREE_TYPE (type);
 207               goto retry;
 208             }
 209           error ("invalid use of array with unspecified bounds");
 210           return;
 211
 212         default:
 213           gcc_unreachable ();
 214         }
 215
 216       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 217         error ("invalid use of undefined type %<%s %E%>",
 218                type_code_string, TYPE_NAME (type));
 219       else
 220         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 221         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 222     }
 223 }
 224
 225 /* Given a type, apply default promotions wrt unnamed function
 226    arguments and return the new type.  */
 227
 228 tree
 229 c_type_promotes_to (tree type)
 230 {
 231   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 232     return double_type_node;
 233
 234   if (c_promoting_integer_type_p (type))
 235     {
 236       /* Preserve unsignedness if not really getting any wider.  */
 237       if (TYPE_UNSIGNED (type)
 238           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 239         return unsigned_type_node;
 240       return integer_type_node;
 241     }
 242
 243   return type;
 244 }
 245
 246 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 247    as well as those of TYPE.  */
 248
 249 static tree
 250 qualify_type (tree type, tree like)
 251 {
 252   return c_build_qualified_type (type,
 253                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 254 }
 255
 256 /* Return true iff the given tree T is a variable length array.  */
 257
 258 bool
 259 c_vla_type_p (const_tree t)
 260 {
 261   if (TREE_CODE (t) == ARRAY_TYPE
 262       && C_TYPE_VARIABLE_SIZE (t))
 263     return true;
 264   return false;
 265 }
 266 \f
 267 /* Return the composite type of two compatible types.
 268
 269    We assume that comptypes has already been done and returned
 270    nonzero; if that isn't so, this may crash.  In particular, we
 271    assume that qualifiers match.  */
 272
 273 tree
 274 composite_type (tree t1, tree t2)
 275 {
 276   enum tree_code code1;
 277   enum tree_code code2;
 278   tree attributes;
 279
 280   /* Save time if the two types are the same.  */
 281
 282   if (t1 == t2) return t1;
 283
 284   /* If one type is nonsense, use the other.  */
 285   if (t1 == error_mark_node)
 286     return t2;
 287   if (t2 == error_mark_node)
 288     return t1;
 289
 290   code1 = TREE_CODE (t1);
 291   code2 = TREE_CODE (t2);
 292
 293   /* Merge the attributes.  */
 294   attributes = targetm.merge_type_attributes (t1, t2);
 295
 296   /* If one is an enumerated type and the other is the compatible
 297      integer type, the composite type might be either of the two
 298      (DR#013 question 3).  For consistency, use the enumerated type as
 299      the composite type.  */
 300
 301   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 302     return t1;
 303   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 304     return t2;
 305
 306   gcc_assert (code1 == code2);
 307
 308   switch (code1)
 309     {
 310     case POINTER_TYPE:
 311       /* For two pointers, do this recursively on the target type.  */
 312       {
 313         tree pointed_to_1 = TREE_TYPE (t1);
 314         tree pointed_to_2 = TREE_TYPE (t2);
 315         tree target = composite_type (pointed_to_1, pointed_to_2);
 316         t1 = build_pointer_type (target);
 317         t1 = build_type_attribute_variant (t1, attributes);
 318         return qualify_type (t1, t2);
 319       }
 320
 321     case ARRAY_TYPE:
 322       {
 323         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 324         int quals;
 325         tree unqual_elt;
 326         tree d1 = TYPE_DOMAIN (t1);
 327         tree d2 = TYPE_DOMAIN (t2);
 328         bool d1_variable, d2_variable;
 329         bool d1_zero, d2_zero;
 330
 331         /* We should not have any type quals on arrays at all.  */
 332         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 333
 334         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 335         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 336
 337         d1_variable = (!d1_zero
 338                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 339                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 340         d2_variable = (!d2_zero
 341                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 342                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 343         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 344         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 345
 346         /* Save space: see if the result is identical to one of the args.  */
 347         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 348             && (d2_variable || d2_zero || !d1_variable))
 349           return build_type_attribute_variant (t1, attributes);
 350         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 351             && (d1_variable || d1_zero || !d2_variable))
 352           return build_type_attribute_variant (t2, attributes);
 353
 354         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 355           return build_type_attribute_variant (t1, attributes);
 356         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 357           return build_type_attribute_variant (t2, attributes);
 358
 359         /* Merge the element types, and have a size if either arg has
 360            one.  We may have qualifiers on the element types.  To set
 361            up TYPE_MAIN_VARIANT correctly, we need to form the
 362            composite of the unqualified types and add the qualifiers
 363            back at the end.  */
 364         quals = TYPE_QUALS (strip_array_types (elt));
 365         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 366         t1 = build_array_type (unqual_elt,
 367                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 368                                              && (d2_variable
 369                                                  || d2_zero
 370                                                  || !d1_variable))
 371                                             ? t1
 372                                             : t2));
 373         t1 = c_build_qualified_type (t1, quals);
 374         return build_type_attribute_variant (t1, attributes);
 375       }
 376
 377     case ENUMERAL_TYPE:
 378     case RECORD_TYPE:
 379     case UNION_TYPE:
 380       if (attributes != NULL)
 381         {
 382           /* Try harder not to create a new aggregate type.  */
 383           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 384             return t1;
 385           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 386             return t2;
 387         }
 388       return build_type_attribute_variant (t1, attributes);
 389
 390     case FUNCTION_TYPE:
 391       /* Function types: prefer the one that specified arg types.
 392          If both do, merge the arg types.  Also merge the return types.  */
 393       {
 394         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 395         tree p1 = TYPE_ARG_TYPES (t1);
 396         tree p2 = TYPE_ARG_TYPES (t2);
 397         int len;
 398         tree newargs, n;
 399         int i;
 400
 401         /* Save space: see if the result is identical to one of the args.  */
 402         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 403           return build_type_attribute_variant (t1, attributes);
 404         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 405           return build_type_attribute_variant (t2, attributes);
 406
 407         /* Simple way if one arg fails to specify argument types.  */
 408         if (TYPE_ARG_TYPES (t1) == 0)
 409          {
 410             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 411             t1 = build_type_attribute_variant (t1, attributes);
 412             return qualify_type (t1, t2);
 413          }
 414         if (TYPE_ARG_TYPES (t2) == 0)
 415          {
 416            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 417            t1 = build_type_attribute_variant (t1, attributes);
 418            return qualify_type (t1, t2);
 419          }
 420
 421         /* If both args specify argument types, we must merge the two
 422            lists, argument by argument.  */
 423         /* Tell global_bindings_p to return false so that variable_size
 424            doesn't die on VLAs in parameter types.  */
 425         c_override_global_bindings_to_false = true;
 426
 427         len = list_length (p1);
 428         newargs = 0;
 429
 430         for (i = 0; i < len; i++)
 431           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 432
 433         n = newargs;
 434
 435         for (; p1;
 436              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 437           {
 438             /* A null type means arg type is not specified.
 439                Take whatever the other function type has.  */
 440             if (TREE_VALUE (p1) == 0)
 441               {
 442                 TREE_VALUE (n) = TREE_VALUE (p2);
 443                 goto parm_done;
 444               }
 445             if (TREE_VALUE (p2) == 0)
 446               {
 447                 TREE_VALUE (n) = TREE_VALUE (p1);
 448                 goto parm_done;
 449               }
 450
 451             /* Given  wait (union {union wait *u; int *i} *)
 452                and  wait (union wait *),
 453                prefer  union wait *  as type of parm.  */
 454             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 455                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 456               {
 457                 tree memb;
 458                 tree mv2 = TREE_VALUE (p2);
 459                 if (mv2 && mv2 != error_mark_node
 460                     && TREE_CODE (mv2) != ARRAY_TYPE)
 461                   mv2 = TYPE_MAIN_VARIANT (mv2);
 462                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 463                      memb; memb = TREE_CHAIN (memb))
 464                   {
 465                     tree mv3 = TREE_TYPE (memb);
 466                     if (mv3 && mv3 != error_mark_node
 467                         && TREE_CODE (mv3) != ARRAY_TYPE)
 468                       mv3 = TYPE_MAIN_VARIANT (mv3);
 469                     if (comptypes (mv3, mv2))
 470                       {
 471                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 472                                                          TREE_VALUE (p2));
 473                         if (pedantic)
 474                           pedwarn ("function types not truly compatible in ISO C");
 475                         goto parm_done;
 476                       }
 477                   }
 478               }
 479             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 480                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 481               {
 482                 tree memb;
 483                 tree mv1 = TREE_VALUE (p1);
 484                 if (mv1 && mv1 != error_mark_node
 485                     && TREE_CODE (mv1) != ARRAY_TYPE)
 486                   mv1 = TYPE_MAIN_VARIANT (mv1);
 487                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 488                      memb; memb = TREE_CHAIN (memb))
 489                   {
 490                     tree mv3 = TREE_TYPE (memb);
 491                     if (mv3 && mv3 != error_mark_node
 492                         && TREE_CODE (mv3) != ARRAY_TYPE)
 493                       mv3 = TYPE_MAIN_VARIANT (mv3);
 494                     if (comptypes (mv3, mv1))
 495                       {
 496                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 497                                                          TREE_VALUE (p1));
 498                         if (pedantic)
 499                           pedwarn ("function types not truly compatible in ISO C");
 500                         goto parm_done;
 501                       }
 502                   }
 503               }
 504             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 505           parm_done: ;
 506           }
 507
 508         c_override_global_bindings_to_false = false;
 509         t1 = build_function_type (valtype, newargs);
 510         t1 = qualify_type (t1, t2);
 511         /* ... falls through ...  */
 512       }
 513
 514     default:
 515       return build_type_attribute_variant (t1, attributes);
 516     }
 517
 518 }
 519
 520 /* Return the type of a conditional expression between pointers to
 521    possibly differently qualified versions of compatible types.
 522
 523    We assume that comp_target_types has already been done and returned
 524    nonzero; if that isn't so, this may crash.  */
 525
 526 static tree
 527 common_pointer_type (tree t1, tree t2)
 528 {
 529   tree attributes;
 530   tree pointed_to_1, mv1;
 531   tree pointed_to_2, mv2;
 532   tree target;
 533   unsigned target_quals;
 534
 535   /* Save time if the two types are the same.  */
 536
 537   if (t1 == t2) return t1;
 538
 539   /* If one type is nonsense, use the other.  */
 540   if (t1 == error_mark_node)
 541     return t2;
 542   if (t2 == error_mark_node)
 543     return t1;
 544
 545   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 546               && TREE_CODE (t2) == POINTER_TYPE);
 547
 548   /* Merge the attributes.  */
 549   attributes = targetm.merge_type_attributes (t1, t2);
 550
 551   /* Find the composite type of the target types, and combine the
 552      qualifiers of the two types' targets.  Do not lose qualifiers on
 553      array element types by taking the TYPE_MAIN_VARIANT.  */
 554   mv1 = pointed_to_1 = TREE_TYPE (t1);
 555   mv2 = pointed_to_2 = TREE_TYPE (t2);
 556   if (TREE_CODE (mv1) != ARRAY_TYPE)
 557     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 558   if (TREE_CODE (mv2) != ARRAY_TYPE)
 559     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 560   target = composite_type (mv1, mv2);
 561
 562   /* For function types do not merge const qualifiers, but drop them
 563      if used inconsistently.  The middle-end uses these to mark const
 564      and noreturn functions.  */
 565   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 566     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 567   else
 568     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 569   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 570   return build_type_attribute_variant (t1, attributes);
 571 }
 572
 573 /* Return the common type for two arithmetic types under the usual
 574    arithmetic conversions.  The default conversions have already been
 575    applied, and enumerated types converted to their compatible integer
 576    types.  The resulting type is unqualified and has no attributes.
 577
 578    This is the type for the result of most arithmetic operations
 579    if the operands have the given two types.  */
 580
 581 static tree
 582 c_common_type (tree t1, tree t2)
 583 {
 584   enum tree_code code1;
 585   enum tree_code code2;
 586
 587   /* If one type is nonsense, use the other.  */
 588   if (t1 == error_mark_node)
 589     return t2;
 590   if (t2 == error_mark_node)
 591     return t1;
 592
 593   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 594     t1 = TYPE_MAIN_VARIANT (t1);
 595
 596   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 597     t2 = TYPE_MAIN_VARIANT (t2);
 598
 599   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 600     t1 = build_type_attribute_variant (t1, NULL_TREE);
 601
 602   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 603     t2 = build_type_attribute_variant (t2, NULL_TREE);
 604
 605   /* Save time if the two types are the same.  */
 606
 607   if (t1 == t2) return t1;
 608
 609   code1 = TREE_CODE (t1);
 610   code2 = TREE_CODE (t2);
 611
 612   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 613               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 614               || code1 == INTEGER_TYPE);
 615   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 616               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 617               || code2 == INTEGER_TYPE);
 618
 619   /* When one operand is a decimal float type, the other operand cannot be
 620      a generic float type or a complex type.  We also disallow vector types
 621      here.  */
 622   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 623       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 624     {
 625       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 626         {
 627           error ("can%'t mix operands of decimal float and vector types");
 628           return error_mark_node;
 629         }
 630       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 631         {
 632           error ("can%'t mix operands of decimal float and complex types");
 633           return error_mark_node;
 634         }
 635       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 636         {
 637           error ("can%'t mix operands of decimal float and other float types");
 638           return error_mark_node;
 639         }
 640     }
 641
 642   /* If one type is a vector type, return that type.  (How the usual
 643      arithmetic conversions apply to the vector types extension is not
 644      precisely specified.)  */
 645   if (code1 == VECTOR_TYPE)
 646     return t1;
 647
 648   if (code2 == VECTOR_TYPE)
 649     return t2;
 650
 651   /* If one type is complex, form the common type of the non-complex
 652      components, then make that complex.  Use T1 or T2 if it is the
 653      required type.  */
 654   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 655     {
 656       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 657       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 658       tree subtype = c_common_type (subtype1, subtype2);
 659
 660       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 661         return t1;
 662       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 663         return t2;
 664       else
 665         return build_complex_type (subtype);
 666     }
 667
 668   /* If only one is real, use it as the result.  */
 669
 670   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 671     return t1;
 672
 673   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 674     return t2;
 675
 676   /* If both are real and either are decimal floating point types, use
 677      the decimal floating point type with the greater precision. */
 678
 679   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 680     {
 681       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 682           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 683         return dfloat128_type_node;
 684       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 685                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 686         return dfloat64_type_node;
 687       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 688                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 689         return dfloat32_type_node;
 690     }
 691
 692   /* Deal with fixed-point types.  */
 693   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 694     {
 695       unsigned int unsignedp = 0, satp = 0;
 696       enum machine_mode m1, m2;
 697       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 698
 699       m1 = TYPE_MODE (t1);
 700       m2 = TYPE_MODE (t2);
 701
 702       /* If one input type is saturating, the result type is saturating.  */
 703       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 704         satp = 1;
 705
 706       /* If both fixed-point types are unsigned, the result type is unsigned.
 707          When mixing fixed-point and integer types, follow the sign of the
 708          fixed-point type.
 709          Otherwise, the result type is signed.  */
 710       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 711            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 712           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 713               && TYPE_UNSIGNED (t1))
 714           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 715               && TYPE_UNSIGNED (t2)))
 716         unsignedp = 1;
 717
 718       /* The result type is signed.  */
 719       if (unsignedp == 0)
 720         {
 721           /* If the input type is unsigned, we need to convert to the
 722              signed type.  */
 723           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 724             {
 725               unsigned char mclass = 0;
 726               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 727                 mclass = MODE_FRACT;
 728               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 729                 mclass = MODE_ACCUM;
 730               else
 731                 gcc_unreachable ();
 732               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 733             }
 734           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 735             {
 736               unsigned char mclass = 0;
 737               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 738                 mclass = MODE_FRACT;
 739               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 740                 mclass = MODE_ACCUM;
 741               else
 742                 gcc_unreachable ();
 743               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 744             }
 745         }
 746
 747       if (code1 == FIXED_POINT_TYPE)
 748         {
 749           fbit1 = GET_MODE_FBIT (m1);
 750           ibit1 = GET_MODE_IBIT (m1);
 751         }
 752       else
 753         {
 754           fbit1 = 0;
 755           /* Signed integers need to subtract one sign bit.  */
 756           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 757         }
 758
 759       if (code2 == FIXED_POINT_TYPE)
 760         {
 761           fbit2 = GET_MODE_FBIT (m2);
 762           ibit2 = GET_MODE_IBIT (m2);
 763         }
 764       else
 765         {
 766           fbit2 = 0;
 767           /* Signed integers need to subtract one sign bit.  */
 768           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 769         }
 770
 771       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 772       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 773       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 774                                                  satp);
 775     }
 776
 777   /* Both real or both integers; use the one with greater precision.  */
 778
 779   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 780     return t1;
 781   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 782     return t2;
 783
 784   /* Same precision.  Prefer long longs to longs to ints when the
 785      same precision, following the C99 rules on integer type rank
 786      (which are equivalent to the C90 rules for C90 types).  */
 787
 788   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 789       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 790     return long_long_unsigned_type_node;
 791
 792   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 793       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 794     {
 795       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 796         return long_long_unsigned_type_node;
 797       else
 798         return long_long_integer_type_node;
 799     }
 800
 801   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 802       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 803     return long_unsigned_type_node;
 804
 805   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 806       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 807     {
 808       /* But preserve unsignedness from the other type,
 809          since long cannot hold all the values of an unsigned int.  */
 810       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 811         return long_unsigned_type_node;
 812       else
 813         return long_integer_type_node;
 814     }
 815
 816   /* Likewise, prefer long double to double even if same size.  */
 817   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 818       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 819     return long_double_type_node;
 820
 821   /* Otherwise prefer the unsigned one.  */
 822
 823   if (TYPE_UNSIGNED (t1))
 824     return t1;
 825   else
 826     return t2;
 827 }
 828 \f
 829 /* Wrapper around c_common_type that is used by c-common.c and other
 830    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 831    are allowed here and are converted to their compatible integer types.
 832    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 833    preferably a non-Boolean type as the common type.  */
 834 tree
 835 common_type (tree t1, tree t2)
 836 {
 837   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 838     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 839   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 840     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 841
 842   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 843   if (TREE_CODE (t1) == BOOLEAN_TYPE
 844       && TREE_CODE (t2) == BOOLEAN_TYPE)
 845     return boolean_type_node;
 846
 847   /* If either type is BOOLEAN_TYPE, then return the other.  */
 848   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 849     return t2;
 850   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 851     return t1;
 852
 853   return c_common_type (t1, t2);
 854 }
 855
 856 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 857    or various other operations.  Return 2 if they are compatible
 858    but a warning may be needed if you use them together.  */
 859
 860 int
 861 comptypes (tree type1, tree type2)
 862 {
 863   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 864   int val;
 865
 866   val = comptypes_internal (type1, type2);
 867   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 868
 869   return val;
 870 }
 871 \f
 872 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 873    or various other operations.  Return 2 if they are compatible
 874    but a warning may be needed if you use them together.  This
 875    differs from comptypes, in that we don't free the seen types.  */
 876
 877 static int
 878 comptypes_internal (const_tree type1, const_tree type2)
 879 {
 880   const_tree t1 = type1;
 881   const_tree t2 = type2;
 882   int attrval, val;
 883
 884   /* Suppress errors caused by previously reported errors.  */
 885
 886   if (t1 == t2 || !t1 || !t2
 887       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 888     return 1;
 889
 890   /* If either type is the internal version of sizetype, return the
 891      language version.  */
 892   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 893       && TYPE_ORIG_SIZE_TYPE (t1))
 894     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 895
 896   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 897       && TYPE_ORIG_SIZE_TYPE (t2))
 898     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 899
 900
 901   /* Enumerated types are compatible with integer types, but this is
 902      not transitive: two enumerated types in the same translation unit
 903      are compatible with each other only if they are the same type.  */
 904
 905   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 906     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 907   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 908     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 909
 910   if (t1 == t2)
 911     return 1;
 912
 913   /* Different classes of types can't be compatible.  */
 914
 915   if (TREE_CODE (t1) != TREE_CODE (t2))
 916     return 0;
 917
 918   /* Qualifiers must match. C99 6.7.3p9 */
 919
 920   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 921     return 0;
 922
 923   /* Allow for two different type nodes which have essentially the same
 924      definition.  Note that we already checked for equality of the type
 925      qualifiers (just above).  */
 926
 927   if (TREE_CODE (t1) != ARRAY_TYPE
 928       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 929     return 1;
 930
 931   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 932   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 933      return 0;
 934
 935   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 936   val = 0;
 937
 938   switch (TREE_CODE (t1))
 939     {
 940     case POINTER_TYPE:
 941       /* Do not remove mode or aliasing information.  */
 942       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 943           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 944         break;
 945       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 946              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 947       break;
 948
 949     case FUNCTION_TYPE:
 950       val = function_types_compatible_p (t1, t2);
 951       break;
 952
 953     case ARRAY_TYPE:
 954       {
 955         tree d1 = TYPE_DOMAIN (t1);
 956         tree d2 = TYPE_DOMAIN (t2);
 957         bool d1_variable, d2_variable;
 958         bool d1_zero, d2_zero;
 959         val = 1;
 960
 961         /* Target types must match incl. qualifiers.  */
 962         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 963             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 964           return 0;
 965
 966         /* Sizes must match unless one is missing or variable.  */
 967         if (d1 == 0 || d2 == 0 || d1 == d2)
 968           break;
 969
 970         d1_zero = !TYPE_MAX_VALUE (d1);
 971         d2_zero = !TYPE_MAX_VALUE (d2);
 972
 973         d1_variable = (!d1_zero
 974                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 975                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 976         d2_variable = (!d2_zero
 977                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 978                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 979         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 980         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 981
 982         if (d1_variable || d2_variable)
 983           break;
 984         if (d1_zero && d2_zero)
 985           break;
 986         if (d1_zero || d2_zero
 987             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 988             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 989           val = 0;
 990
 991         break;
 992       }
 993
 994     case ENUMERAL_TYPE:
 995     case RECORD_TYPE:
 996     case UNION_TYPE:
 997       if (val != 1 && !same_translation_unit_p (t1, t2))
 998         {
 999           tree a1 = TYPE_ATTRIBUTES (t1);
1000           tree a2 = TYPE_ATTRIBUTES (t2);
1001
1002           if (! attribute_list_contained (a1, a2)
1003               && ! attribute_list_contained (a2, a1))
1004             break;
1005
1006           if (attrval != 2)
1007             return tagged_types_tu_compatible_p (t1, t2);
1008           val = tagged_types_tu_compatible_p (t1, t2);
1009         }
1010       break;
1011
1012     case VECTOR_TYPE:
1013       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1014             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1015       break;
1016
1017     default:
1018       break;
1019     }
1020   return attrval == 2 && val == 1 ? 2 : val;
1021 }
1022
1023 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1024    ignoring their qualifiers.  */
1025
1026 static int
1027 comp_target_types (tree ttl, tree ttr)
1028 {
1029   int val;
1030   tree mvl, mvr;
1031
1032   /* Do not lose qualifiers on element types of array types that are
1033      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1034   mvl = TREE_TYPE (ttl);
1035   mvr = TREE_TYPE (ttr);
1036   if (TREE_CODE (mvl) != ARRAY_TYPE)
1037     mvl = TYPE_MAIN_VARIANT (mvl);
1038   if (TREE_CODE (mvr) != ARRAY_TYPE)
1039     mvr = TYPE_MAIN_VARIANT (mvr);
1040   val = comptypes (mvl, mvr);
1041
1042   if (val == 2 && pedantic)
1043     pedwarn ("types are not quite compatible");
1044   return val;
1045 }
1046 \f
1047 /* Subroutines of `comptypes'.  */
1048
1049 /* Determine whether two trees derive from the same translation unit.
1050    If the CONTEXT chain ends in a null, that tree's context is still
1051    being parsed, so if two trees have context chains ending in null,
1052    they're in the same translation unit.  */
1053 int
1054 same_translation_unit_p (const_tree t1, const_tree t2)
1055 {
1056   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1057     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1058       {
1059       case tcc_declaration:
1060         t1 = DECL_CONTEXT (t1); break;
1061       case tcc_type:
1062         t1 = TYPE_CONTEXT (t1); break;
1063       case tcc_exceptional:
1064         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1065       default: gcc_unreachable ();
1066       }
1067
1068   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1069     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1070       {
1071       case tcc_declaration:
1072         t2 = DECL_CONTEXT (t2); break;
1073       case tcc_type:
1074         t2 = TYPE_CONTEXT (t2); break;
1075       case tcc_exceptional:
1076         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1077       default: gcc_unreachable ();
1078       }
1079
1080   return t1 == t2;
1081 }
1082
1083 /* Allocate the seen two types, assuming that they are compatible. */
1084
1085 static struct tagged_tu_seen_cache *
1086 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1087 {
1088   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1089   tu->next = tagged_tu_seen_base;
1090   tu->t1 = t1;
1091   tu->t2 = t2;
1092
1093   tagged_tu_seen_base = tu;
1094
1095   /* The C standard says that two structures in different translation
1096      units are compatible with each other only if the types of their
1097      fields are compatible (among other things).  We assume that they
1098      are compatible until proven otherwise when building the cache.
1099      An example where this can occur is:
1100      struct a
1101      {
1102        struct a *next;
1103      };
1104      If we are comparing this against a similar struct in another TU,
1105      and did not assume they were compatible, we end up with an infinite
1106      loop.  */
1107   tu->val = 1;
1108   return tu;
1109 }
1110
1111 /* Free the seen types until we get to TU_TIL. */
1112
1113 static void
1114 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1115 {
1116   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1117   while (tu != tu_til)
1118     {
1119       const struct tagged_tu_seen_cache *const tu1
1120         = (const struct tagged_tu_seen_cache *) tu;
1121       tu = tu1->next;
1122       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1123     }
1124   tagged_tu_seen_base = tu_til;
1125 }
1126
1127 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1128    compatible.  If the two types are not the same (which has been
1129    checked earlier), this can only happen when multiple translation
1130    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1131    rules.  */
1132
1133 static int
1134 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1135 {
1136   tree s1, s2;
1137   bool needs_warning = false;
1138
1139   /* We have to verify that the tags of the types are the same.  This
1140      is harder than it looks because this may be a typedef, so we have
1141      to go look at the original type.  It may even be a typedef of a
1142      typedef...
1143      In the case of compiler-created builtin structs the TYPE_DECL
1144      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1145   while (TYPE_NAME (t1)
1146          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1147          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1148     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1149
1150   while (TYPE_NAME (t2)
1151          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1152          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1153     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1154
1155   /* C90 didn't have the requirement that the two tags be the same.  */
1156   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1157     return 0;
1158
1159   /* C90 didn't say what happened if one or both of the types were
1160      incomplete; we choose to follow C99 rules here, which is that they
1161      are compatible.  */
1162   if (TYPE_SIZE (t1) == NULL
1163       || TYPE_SIZE (t2) == NULL)
1164     return 1;
1165
1166   {
1167     const struct tagged_tu_seen_cache * tts_i;
1168     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1169       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1170         return tts_i->val;
1171   }
1172
1173   switch (TREE_CODE (t1))
1174     {
1175     case ENUMERAL_TYPE:
1176       {
1177         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1178         /* Speed up the case where the type values are in the same order.  */
1179         tree tv1 = TYPE_VALUES (t1);
1180         tree tv2 = TYPE_VALUES (t2);
1181
1182         if (tv1 == tv2)
1183           {
1184             return 1;
1185           }
1186
1187         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1188           {
1189             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1190               break;
1191             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1192               {
1193                 tu->val = 0;
1194                 return 0;
1195               }
1196           }
1197
1198         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1199           {
1200             return 1;
1201           }
1202         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1203           {
1204             tu->val = 0;
1205             return 0;
1206           }
1207
1208         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1209           {
1210             tu->val = 0;
1211             return 0;
1212           }
1213
1214         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1215           {
1216             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1217             if (s2 == NULL
1218                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1219               {
1220                 tu->val = 0;
1221                 return 0;
1222               }
1223           }
1224         return 1;
1225       }
1226
1227     case UNION_TYPE:
1228       {
1229         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1230         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1231           {
1232             tu->val = 0;
1233             return 0;
1234           }
1235
1236         /*  Speed up the common case where the fields are in the same order. */
1237         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1238              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1239           {
1240             int result;
1241
1242             if (DECL_NAME (s1) != DECL_NAME (s2))
1243               break;
1244             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1245
1246             if (result != 1 && !DECL_NAME (s1))
1247               break;
1248             if (result == 0)
1249               {
1250                 tu->val = 0;
1251                 return 0;
1252               }
1253             if (result == 2)
1254               needs_warning = true;
1255
1256             if (TREE_CODE (s1) == FIELD_DECL
1257                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1258                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1259               {
1260                 tu->val = 0;
1261                 return 0;
1262               }
1263           }
1264         if (!s1 && !s2)
1265           {
1266             tu->val = needs_warning ? 2 : 1;
1267             return tu->val;
1268           }
1269
1270         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1271           {
1272             bool ok = false;
1273
1274             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1275               if (DECL_NAME (s1) == DECL_NAME (s2))
1276                 {
1277                   int result;
1278
1279                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1280
1281                   if (result != 1 && !DECL_NAME (s1))
1282                     continue;
1283                   if (result == 0)
1284                     {
1285                       tu->val = 0;
1286                       return 0;
1287                     }
1288                   if (result == 2)
1289                     needs_warning = true;
1290
1291                   if (TREE_CODE (s1) == FIELD_DECL
1292                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1293                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1294                     break;
1295
1296                   ok = true;
1297                   break;
1298                 }
1299             if (!ok)
1300               {
1301                 tu->val = 0;
1302                 return 0;
1303               }
1304           }
1305         tu->val = needs_warning ? 2 : 10;
1306         return tu->val;
1307       }
1308
1309     case RECORD_TYPE:
1310       {
1311         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1312
1313         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1314              s1 && s2;
1315              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1316           {
1317             int result;
1318             if (TREE_CODE (s1) != TREE_CODE (s2)
1319                 || DECL_NAME (s1) != DECL_NAME (s2))
1320               break;
1321             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1322             if (result == 0)
1323               break;
1324             if (result == 2)
1325               needs_warning = true;
1326
1327             if (TREE_CODE (s1) == FIELD_DECL
1328                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1329                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1330               break;
1331           }
1332         if (s1 && s2)
1333           tu->val = 0;
1334         else
1335           tu->val = needs_warning ? 2 : 1;
1336         return tu->val;
1337       }
1338
1339     default:
1340       gcc_unreachable ();
1341     }
1342 }
1343
1344 /* Return 1 if two function types F1 and F2 are compatible.
1345    If either type specifies no argument types,
1346    the other must specify a fixed number of self-promoting arg types.
1347    Otherwise, if one type specifies only the number of arguments,
1348    the other must specify that number of self-promoting arg types.
1349    Otherwise, the argument types must match.  */
1350
1351 static int
1352 function_types_compatible_p (const_tree f1, const_tree f2)
1353 {
1354   tree args1, args2;
1355   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1356   int val = 1;
1357   int val1;
1358   tree ret1, ret2;
1359
1360   ret1 = TREE_TYPE (f1);
1361   ret2 = TREE_TYPE (f2);
1362
1363   /* 'volatile' qualifiers on a function's return type used to mean
1364      the function is noreturn.  */
1365   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1366     pedwarn ("function return types not compatible due to %<volatile%>");
1367   if (TYPE_VOLATILE (ret1))
1368     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1369                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1370   if (TYPE_VOLATILE (ret2))
1371     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1372                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1373   val = comptypes_internal (ret1, ret2);
1374   if (val == 0)
1375     return 0;
1376
1377   args1 = TYPE_ARG_TYPES (f1);
1378   args2 = TYPE_ARG_TYPES (f2);
1379
1380   /* An unspecified parmlist matches any specified parmlist
1381      whose argument types don't need default promotions.  */
1382
1383   if (args1 == 0)
1384     {
1385       if (!self_promoting_args_p (args2))
1386         return 0;
1387       /* If one of these types comes from a non-prototype fn definition,
1388          compare that with the other type's arglist.
1389          If they don't match, ask for a warning (but no error).  */
1390       if (TYPE_ACTUAL_ARG_TYPES (f1)
1391           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1392         val = 2;
1393       return val;
1394     }
1395   if (args2 == 0)
1396     {
1397       if (!self_promoting_args_p (args1))
1398         return 0;
1399       if (TYPE_ACTUAL_ARG_TYPES (f2)
1400           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1401         val = 2;
1402       return val;
1403     }
1404
1405   /* Both types have argument lists: compare them and propagate results.  */
1406   val1 = type_lists_compatible_p (args1, args2);
1407   return val1 != 1 ? val1 : val;
1408 }
1409
1410 /* Check two lists of types for compatibility,
1411    returning 0 for incompatible, 1 for compatible,
1412    or 2 for compatible with warning.  */
1413
1414 static int
1415 type_lists_compatible_p (const_tree args1, const_tree args2)
1416 {
1417   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1418   int val = 1;
1419   int newval = 0;
1420
1421   while (1)
1422     {
1423       tree a1, mv1, a2, mv2;
1424       if (args1 == 0 && args2 == 0)
1425         return val;
1426       /* If one list is shorter than the other,
1427          they fail to match.  */
1428       if (args1 == 0 || args2 == 0)
1429         return 0;
1430       mv1 = a1 = TREE_VALUE (args1);
1431       mv2 = a2 = TREE_VALUE (args2);
1432       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1433         mv1 = TYPE_MAIN_VARIANT (mv1);
1434       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1435         mv2 = TYPE_MAIN_VARIANT (mv2);
1436       /* A null pointer instead of a type
1437          means there is supposed to be an argument
1438          but nothing is specified about what type it has.
1439          So match anything that self-promotes.  */
1440       if (a1 == 0)
1441         {
1442           if (c_type_promotes_to (a2) != a2)
1443             return 0;
1444         }
1445       else if (a2 == 0)
1446         {
1447           if (c_type_promotes_to (a1) != a1)
1448             return 0;
1449         }
1450       /* If one of the lists has an error marker, ignore this arg.  */
1451       else if (TREE_CODE (a1) == ERROR_MARK
1452                || TREE_CODE (a2) == ERROR_MARK)
1453         ;
1454       else if (!(newval = comptypes_internal (mv1, mv2)))
1455         {
1456           /* Allow  wait (union {union wait *u; int *i} *)
1457              and  wait (union wait *)  to be compatible.  */
1458           if (TREE_CODE (a1) == UNION_TYPE
1459               && (TYPE_NAME (a1) == 0
1460                   || TYPE_TRANSPARENT_UNION (a1))
1461               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1462               && tree_int_cst_equal (TYPE_SIZE (a1),
1463                                      TYPE_SIZE (a2)))
1464             {
1465               tree memb;
1466               for (memb = TYPE_FIELDS (a1);
1467                    memb; memb = TREE_CHAIN (memb))
1468                 {
1469                   tree mv3 = TREE_TYPE (memb);
1470                   if (mv3 && mv3 != error_mark_node
1471                       && TREE_CODE (mv3) != ARRAY_TYPE)
1472                     mv3 = TYPE_MAIN_VARIANT (mv3);
1473                   if (comptypes_internal (mv3, mv2))
1474                     break;
1475                 }
1476               if (memb == 0)
1477                 return 0;
1478             }
1479           else if (TREE_CODE (a2) == UNION_TYPE
1480                    && (TYPE_NAME (a2) == 0
1481                        || TYPE_TRANSPARENT_UNION (a2))
1482                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1483                    && tree_int_cst_equal (TYPE_SIZE (a2),
1484                                           TYPE_SIZE (a1)))
1485             {
1486               tree memb;
1487               for (memb = TYPE_FIELDS (a2);
1488                    memb; memb = TREE_CHAIN (memb))
1489                 {
1490                   tree mv3 = TREE_TYPE (memb);
1491                   if (mv3 && mv3 != error_mark_node
1492                       && TREE_CODE (mv3) != ARRAY_TYPE)
1493                     mv3 = TYPE_MAIN_VARIANT (mv3);
1494                   if (comptypes_internal (mv3, mv1))
1495                     break;
1496                 }
1497               if (memb == 0)
1498                 return 0;
1499             }
1500           else
1501             return 0;
1502         }
1503
1504       /* comptypes said ok, but record if it said to warn.  */
1505       if (newval > val)
1506         val = newval;
1507
1508       args1 = TREE_CHAIN (args1);
1509       args2 = TREE_CHAIN (args2);
1510     }
1511 }
1512 \f
1513 /* Compute the size to increment a pointer by.  */
1514
1515 static tree
1516 c_size_in_bytes (const_tree type)
1517 {
1518   enum tree_code code = TREE_CODE (type);
1519
1520   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1521     return size_one_node;
1522
1523   if (!COMPLETE_OR_VOID_TYPE_P (type))
1524     {
1525       error ("arithmetic on pointer to an incomplete type");
1526       return size_one_node;
1527     }
1528
1529   /* Convert in case a char is more than one unit.  */
1530   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1531                      size_int (TYPE_PRECISION (char_type_node)
1532                                / BITS_PER_UNIT));
1533 }
1534 \f
1535 /* Return either DECL or its known constant value (if it has one).  */
1536
1537 tree
1538 decl_constant_value (tree decl)
1539 {
1540   if (/* Don't change a variable array bound or initial value to a constant
1541          in a place where a variable is invalid.  Note that DECL_INITIAL
1542          isn't valid for a PARM_DECL.  */
1543       current_function_decl != 0
1544       && TREE_CODE (decl) != PARM_DECL
1545       && !TREE_THIS_VOLATILE (decl)
1546       && TREE_READONLY (decl)
1547       && DECL_INITIAL (decl) != 0
1548       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1549       /* This is invalid if initial value is not constant.
1550          If it has either a function call, a memory reference,
1551          or a variable, then re-evaluating it could give different results.  */
1552       && TREE_CONSTANT (DECL_INITIAL (decl))
1553       /* Check for cases where this is sub-optimal, even though valid.  */
1554       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1555     return DECL_INITIAL (decl);
1556   return decl;
1557 }
1558
1559 /* Return either DECL or its known constant value (if it has one), but
1560    return DECL if pedantic or DECL has mode BLKmode.  This is for
1561    bug-compatibility with the old behavior of decl_constant_value
1562    (before GCC 3.0); every use of this function is a bug and it should
1563    be removed before GCC 3.1.  It is not appropriate to use pedantic
1564    in a way that affects optimization, and BLKmode is probably not the
1565    right test for avoiding misoptimizations either.  */
1566
1567 static tree
1568 decl_constant_value_for_broken_optimization (tree decl)
1569 {
1570   tree ret;
1571
1572   if (pedantic || DECL_MODE (decl) == BLKmode)
1573     return decl;
1574
1575   ret = decl_constant_value (decl);
1576   /* Avoid unwanted tree sharing between the initializer and current
1577      function's body where the tree can be modified e.g. by the
1578      gimplifier.  */
1579   if (ret != decl && TREE_STATIC (decl))
1580     ret = unshare_expr (ret);
1581   return ret;
1582 }
1583
1584 /* Convert the array expression EXP to a pointer.  */
1585 static tree
1586 array_to_pointer_conversion (tree exp)
1587 {
1588   tree orig_exp = exp;
1589   tree type = TREE_TYPE (exp);
1590   tree adr;
1591   tree restype = TREE_TYPE (type);
1592   tree ptrtype;
1593
1594   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1595
1596   STRIP_TYPE_NOPS (exp);
1597
1598   if (TREE_NO_WARNING (orig_exp))
1599     TREE_NO_WARNING (exp) = 1;
1600
1601   ptrtype = build_pointer_type (restype);
1602
1603   if (TREE_CODE (exp) == INDIRECT_REF)
1604     return convert (ptrtype, TREE_OPERAND (exp, 0));
1605
1606   if (TREE_CODE (exp) == VAR_DECL)
1607     {
1608       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1609          ADDR_EXPR because it's the best way of representing what
1610          happens in C when we take the address of an array and place
1611          it in a pointer to the element type.  */
1612       adr = build1 (ADDR_EXPR, ptrtype, exp);
1613       if (!c_mark_addressable (exp))
1614         return error_mark_node;
1615       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1616       return adr;
1617     }
1618
1619   /* This way is better for a COMPONENT_REF since it can
1620      simplify the offset for a component.  */
1621   adr = build_unary_op (ADDR_EXPR, exp, 1);
1622   return convert (ptrtype, adr);
1623 }
1624
1625 /* Convert the function expression EXP to a pointer.  */
1626 static tree
1627 function_to_pointer_conversion (tree exp)
1628 {
1629   tree orig_exp = exp;
1630
1631   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1632
1633   STRIP_TYPE_NOPS (exp);
1634
1635   if (TREE_NO_WARNING (orig_exp))
1636     TREE_NO_WARNING (exp) = 1;
1637
1638   return build_unary_op (ADDR_EXPR, exp, 0);
1639 }
1640
1641 /* Perform the default conversion of arrays and functions to pointers.
1642    Return the result of converting EXP.  For any other expression, just
1643    return EXP after removing NOPs.  */
1644
1645 struct c_expr
1646 default_function_array_conversion (struct c_expr exp)
1647 {
1648   tree orig_exp = exp.value;
1649   tree type = TREE_TYPE (exp.value);
1650   enum tree_code code = TREE_CODE (type);
1651
1652   switch (code)
1653     {
1654     case ARRAY_TYPE:
1655       {
1656         bool not_lvalue = false;
1657         bool lvalue_array_p;
1658
1659         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1660                 || TREE_CODE (exp.value) == NOP_EXPR
1661                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1662                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1663           {
1664             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1665               not_lvalue = true;
1666             exp.value = TREE_OPERAND (exp.value, 0);
1667           }
1668
1669         if (TREE_NO_WARNING (orig_exp))
1670           TREE_NO_WARNING (exp.value) = 1;
1671
1672         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1673         if (!flag_isoc99 && !lvalue_array_p)
1674           {
1675             /* Before C99, non-lvalue arrays do not decay to pointers.
1676                Normally, using such an array would be invalid; but it can
1677                be used correctly inside sizeof or as a statement expression.
1678                Thus, do not give an error here; an error will result later.  */
1679             return exp;
1680           }
1681
1682         exp.value = array_to_pointer_conversion (exp.value);
1683       }
1684       break;
1685     case FUNCTION_TYPE:
1686       exp.value = function_to_pointer_conversion (exp.value);
1687       break;
1688     default:
1689       STRIP_TYPE_NOPS (exp.value);
1690       if (TREE_NO_WARNING (orig_exp))
1691         TREE_NO_WARNING (exp.value) = 1;
1692       break;
1693     }
1694
1695   return exp;
1696 }
1697
1698
1699 /* EXP is an expression of integer type.  Apply the integer promotions
1700    to it and return the promoted value.  */
1701
1702 tree
1703 perform_integral_promotions (tree exp)
1704 {
1705   tree type = TREE_TYPE (exp);
1706   enum tree_code code = TREE_CODE (type);
1707
1708   gcc_assert (INTEGRAL_TYPE_P (type));
1709
1710   /* Normally convert enums to int,
1711      but convert wide enums to something wider.  */
1712   if (code == ENUMERAL_TYPE)
1713     {
1714       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1715                                           TYPE_PRECISION (integer_type_node)),
1716                                      ((TYPE_PRECISION (type)
1717                                        >= TYPE_PRECISION (integer_type_node))
1718                                       && TYPE_UNSIGNED (type)));
1719
1720       return convert (type, exp);
1721     }
1722
1723   /* ??? This should no longer be needed now bit-fields have their
1724      proper types.  */
1725   if (TREE_CODE (exp) == COMPONENT_REF
1726       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1727       /* If it's thinner than an int, promote it like a
1728          c_promoting_integer_type_p, otherwise leave it alone.  */
1729       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1730                                TYPE_PRECISION (integer_type_node)))
1731     return convert (integer_type_node, exp);
1732
1733   if (c_promoting_integer_type_p (type))
1734     {
1735       /* Preserve unsignedness if not really getting any wider.  */
1736       if (TYPE_UNSIGNED (type)
1737           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1738         return convert (unsigned_type_node, exp);
1739
1740       return convert (integer_type_node, exp);
1741     }
1742
1743   return exp;
1744 }
1745
1746
1747 /* Perform default promotions for C data used in expressions.
1748    Enumeral types or short or char are converted to int.
1749    In addition, manifest constants symbols are replaced by their values.  */
1750
1751 tree
1752 default_conversion (tree exp)
1753 {
1754   tree orig_exp;
1755   tree type = TREE_TYPE (exp);
1756   enum tree_code code = TREE_CODE (type);
1757
1758   /* Functions and arrays have been converted during parsing.  */
1759   gcc_assert (code != FUNCTION_TYPE);
1760   if (code == ARRAY_TYPE)
1761     return exp;
1762
1763   /* Constants can be used directly unless they're not loadable.  */
1764   if (TREE_CODE (exp) == CONST_DECL)
1765     exp = DECL_INITIAL (exp);
1766
1767   /* Replace a nonvolatile const static variable with its value unless
1768      it is an array, in which case we must be sure that taking the
1769      address of the array produces consistent results.  */
1770   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1771     {
1772       exp = decl_constant_value_for_broken_optimization (exp);
1773       type = TREE_TYPE (exp);
1774     }
1775
1776   /* Strip no-op conversions.  */
1777   orig_exp = exp;
1778   STRIP_TYPE_NOPS (exp);
1779
1780   if (TREE_NO_WARNING (orig_exp))
1781     TREE_NO_WARNING (exp) = 1;
1782
1783   if (code == VOID_TYPE)
1784     {
1785       error ("void value not ignored as it ought to be");
1786       return error_mark_node;
1787     }
1788
1789   exp = require_complete_type (exp);
1790   if (exp == error_mark_node)
1791     return error_mark_node;
1792
1793   if (INTEGRAL_TYPE_P (type))
1794     return perform_integral_promotions (exp);
1795
1796   return exp;
1797 }
1798 \f
1799 /* Look up COMPONENT in a structure or union DECL.
1800
1801    If the component name is not found, returns NULL_TREE.  Otherwise,
1802    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1803    stepping down the chain to the component, which is in the last
1804    TREE_VALUE of the list.  Normally the list is of length one, but if
1805    the component is embedded within (nested) anonymous structures or
1806    unions, the list steps down the chain to the component.  */
1807
1808 static tree
1809 lookup_field (tree decl, tree component)
1810 {
1811   tree type = TREE_TYPE (decl);
1812   tree field;
1813
1814   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1815      to the field elements.  Use a binary search on this array to quickly
1816      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1817      will always be set for structures which have many elements.  */
1818
1819   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1820     {
1821       int bot, top, half;
1822       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1823
1824       field = TYPE_FIELDS (type);
1825       bot = 0;
1826       top = TYPE_LANG_SPECIFIC (type)->s->len;
1827       while (top - bot > 1)
1828         {
1829           half = (top - bot + 1) >> 1;
1830           field = field_array[bot+half];
1831
1832           if (DECL_NAME (field) == NULL_TREE)
1833             {
1834               /* Step through all anon unions in linear fashion.  */
1835               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1836                 {
1837                   field = field_array[bot++];
1838                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1839                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1840                     {
1841                       tree anon = lookup_field (field, component);
1842
1843                       if (anon)
1844                         return tree_cons (NULL_TREE, field, anon);
1845                     }
1846                 }
1847
1848               /* Entire record is only anon unions.  */
1849               if (bot > top)
1850                 return NULL_TREE;
1851
1852               /* Restart the binary search, with new lower bound.  */
1853               continue;
1854             }
1855
1856           if (DECL_NAME (field) == component)
1857             break;
1858           if (DECL_NAME (field) < component)
1859             bot += half;
1860           else
1861             top = bot + half;
1862         }
1863
1864       if (DECL_NAME (field_array[bot]) == component)
1865         field = field_array[bot];
1866       else if (DECL_NAME (field) != component)
1867         return NULL_TREE;
1868     }
1869   else
1870     {
1871       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1872         {
1873           if (DECL_NAME (field) == NULL_TREE
1874               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1875                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1876             {
1877               tree anon = lookup_field (field, component);
1878
1879               if (anon)
1880                 return tree_cons (NULL_TREE, field, anon);
1881             }
1882
1883           if (DECL_NAME (field) == component)
1884             break;
1885         }
1886
1887       if (field == NULL_TREE)
1888         return NULL_TREE;
1889     }
1890
1891   return tree_cons (NULL_TREE, field, NULL_TREE);
1892 }
1893
1894 /* Make an expression to refer to the COMPONENT field of
1895    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1896
1897 tree
1898 build_component_ref (tree datum, tree component)
1899 {
1900   tree type = TREE_TYPE (datum);
1901   enum tree_code code = TREE_CODE (type);
1902   tree field = NULL;
1903   tree ref;
1904
1905   if (!objc_is_public (datum, component))
1906     return error_mark_node;
1907
1908   /* See if there is a field or component with name COMPONENT.  */
1909
1910   if (code == RECORD_TYPE || code == UNION_TYPE)
1911     {
1912       if (!COMPLETE_TYPE_P (type))
1913         {
1914           c_incomplete_type_error (NULL_TREE, type);
1915           return error_mark_node;
1916         }
1917
1918       field = lookup_field (datum, component);
1919
1920       if (!field)
1921         {
1922           error ("%qT has no member named %qE", type, component);
1923           return error_mark_node;
1924         }
1925
1926       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1927          This might be better solved in future the way the C++ front
1928          end does it - by giving the anonymous entities each a
1929          separate name and type, and then have build_component_ref
1930          recursively call itself.  We can't do that here.  */
1931       do
1932         {
1933           tree subdatum = TREE_VALUE (field);
1934           int quals;
1935           tree subtype;
1936
1937           if (TREE_TYPE (subdatum) == error_mark_node)
1938             return error_mark_node;
1939
1940           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1941           quals |= TYPE_QUALS (TREE_TYPE (datum));
1942           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1943
1944           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1945                         NULL_TREE);
1946           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1947             TREE_READONLY (ref) = 1;
1948           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1949             TREE_THIS_VOLATILE (ref) = 1;
1950
1951           if (TREE_DEPRECATED (subdatum))
1952             warn_deprecated_use (subdatum);
1953
1954           datum = ref;
1955
1956           field = TREE_CHAIN (field);
1957         }
1958       while (field);
1959
1960       return ref;
1961     }
1962   else if (code != ERROR_MARK)
1963     error ("request for member %qE in something not a structure or union",
1964            component);
1965
1966   return error_mark_node;
1967 }
1968 \f
1969 /* Given an expression PTR for a pointer, return an expression
1970    for the value pointed to.
1971    ERRORSTRING is the name of the operator to appear in error messages.  */
1972
1973 tree
1974 build_indirect_ref (tree ptr, const char *errorstring)
1975 {
1976   tree pointer = default_conversion (ptr);
1977   tree type = TREE_TYPE (pointer);
1978
1979   if (TREE_CODE (type) == POINTER_TYPE)
1980     {
1981       if (TREE_CODE (pointer) == CONVERT_EXPR
1982           || TREE_CODE (pointer) == NOP_EXPR
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         return TREE_OPERAND (pointer, 0);
1998       else
1999         {
2000           tree t = TREE_TYPE (type);
2001           tree ref;
2002
2003           ref = build1 (INDIRECT_REF, t, pointer);
2004
2005           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2006             {
2007               error ("dereferencing pointer to incomplete type");
2008               return error_mark_node;
2009             }
2010           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2011             warning (0, "dereferencing %<void *%> pointer");
2012
2013           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2014              so that we get the proper error message if the result is used
2015              to assign to.  Also, &* is supposed to be a no-op.
2016              And ANSI C seems to specify that the type of the result
2017              should be the const type.  */
2018           /* A de-reference of a pointer to const is not a const.  It is valid
2019              to change it via some other pointer.  */
2020           TREE_READONLY (ref) = TYPE_READONLY (t);
2021           TREE_SIDE_EFFECTS (ref)
2022             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2023           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2024           return ref;
2025         }
2026     }
2027   else if (TREE_CODE (pointer) != ERROR_MARK)
2028     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2029   return error_mark_node;
2030 }
2031
2032 /* This handles expressions of the form "a[i]", which denotes
2033    an array reference.
2034
2035    This is logically equivalent in C to *(a+i), but we may do it differently.
2036    If A is a variable or a member, we generate a primitive ARRAY_REF.
2037    This avoids forcing the array out of registers, and can work on
2038    arrays that are not lvalues (for example, members of structures returned
2039    by functions).  */
2040
2041 tree
2042 build_array_ref (tree array, tree index)
2043 {
2044   bool swapped = false;
2045   if (TREE_TYPE (array) == error_mark_node
2046       || TREE_TYPE (index) == error_mark_node)
2047     return error_mark_node;
2048
2049   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2050       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2051     {
2052       tree temp;
2053       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2054           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2055         {
2056           error ("subscripted value is neither array nor pointer");
2057           return error_mark_node;
2058         }
2059       temp = array;
2060       array = index;
2061       index = temp;
2062       swapped = true;
2063     }
2064
2065   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2066     {
2067       error ("array subscript is not an integer");
2068       return error_mark_node;
2069     }
2070
2071   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2072     {
2073       error ("subscripted value is pointer to function");
2074       return error_mark_node;
2075     }
2076
2077   /* ??? Existing practice has been to warn only when the char
2078      index is syntactically the index, not for char[array].  */
2079   if (!swapped)
2080      warn_array_subscript_with_type_char (index);
2081
2082   /* Apply default promotions *after* noticing character types.  */
2083   index = default_conversion (index);
2084
2085   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2086
2087   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2088     {
2089       tree rval, type;
2090
2091       /* An array that is indexed by a non-constant
2092          cannot be stored in a register; we must be able to do
2093          address arithmetic on its address.
2094          Likewise an array of elements of variable size.  */
2095       if (TREE_CODE (index) != INTEGER_CST
2096           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2097               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2098         {
2099           if (!c_mark_addressable (array))
2100             return error_mark_node;
2101         }
2102       /* An array that is indexed by a constant value which is not within
2103          the array bounds cannot be stored in a register either; because we
2104          would get a crash in store_bit_field/extract_bit_field when trying
2105          to access a non-existent part of the register.  */
2106       if (TREE_CODE (index) == INTEGER_CST
2107           && TYPE_DOMAIN (TREE_TYPE (array))
2108           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2109         {
2110           if (!c_mark_addressable (array))
2111             return error_mark_node;
2112         }
2113
2114       if (pedantic)
2115         {
2116           tree foo = array;
2117           while (TREE_CODE (foo) == COMPONENT_REF)
2118             foo = TREE_OPERAND (foo, 0);
2119           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2120             pedwarn ("ISO C forbids subscripting %<register%> array");
2121           else if (!flag_isoc99 && !lvalue_p (foo))
2122             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2123         }
2124
2125       type = TREE_TYPE (TREE_TYPE (array));
2126       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2127       /* Array ref is const/volatile if the array elements are
2128          or if the array is.  */
2129       TREE_READONLY (rval)
2130         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2131             | TREE_READONLY (array));
2132       TREE_SIDE_EFFECTS (rval)
2133         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2134             | TREE_SIDE_EFFECTS (array));
2135       TREE_THIS_VOLATILE (rval)
2136         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2137             /* This was added by rms on 16 Nov 91.
2138                It fixes  vol struct foo *a;  a->elts[1]
2139                in an inline function.
2140                Hope it doesn't break something else.  */
2141             | TREE_THIS_VOLATILE (array));
2142       return require_complete_type (fold (rval));
2143     }
2144   else
2145     {
2146       tree ar = default_conversion (array);
2147
2148       if (ar == error_mark_node)
2149         return ar;
2150
2151       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2152       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2153
2154       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2155                                  "array indexing");
2156     }
2157 }
2158 \f
2159 /* Build an external reference to identifier ID.  FUN indicates
2160    whether this will be used for a function call.  LOC is the source
2161    location of the identifier.  */
2162 tree
2163 build_external_ref (tree id, int fun, location_t loc)
2164 {
2165   tree ref;
2166   tree decl = lookup_name (id);
2167
2168   /* In Objective-C, an instance variable (ivar) may be preferred to
2169      whatever lookup_name() found.  */
2170   decl = objc_lookup_ivar (decl, id);
2171
2172   if (decl && decl != error_mark_node)
2173     ref = decl;
2174   else if (fun)
2175     /* Implicit function declaration.  */
2176     ref = implicitly_declare (id);
2177   else if (decl == error_mark_node)
2178     /* Don't complain about something that's already been
2179        complained about.  */
2180     return error_mark_node;
2181   else
2182     {
2183       undeclared_variable (id, loc);
2184       return error_mark_node;
2185     }
2186
2187   if (TREE_TYPE (ref) == error_mark_node)
2188     return error_mark_node;
2189
2190   if (TREE_DEPRECATED (ref))
2191     warn_deprecated_use (ref);
2192
2193   /* Recursive call does not count as usage.  */
2194   if (ref != current_function_decl)
2195     {
2196       if (!skip_evaluation)
2197         assemble_external (ref);
2198       TREE_USED (ref) = 1;
2199     }
2200
2201   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2202     {
2203       if (!in_sizeof && !in_typeof)
2204         C_DECL_USED (ref) = 1;
2205       else if (DECL_INITIAL (ref) == 0
2206                && DECL_EXTERNAL (ref)
2207                && !TREE_PUBLIC (ref))
2208         record_maybe_used_decl (ref);
2209     }
2210
2211   if (TREE_CODE (ref) == CONST_DECL)
2212     {
2213       used_types_insert (TREE_TYPE (ref));
2214       ref = DECL_INITIAL (ref);
2215       TREE_CONSTANT (ref) = 1;
2216       TREE_INVARIANT (ref) = 1;
2217     }
2218   else if (current_function_decl != 0
2219            && !DECL_FILE_SCOPE_P (current_function_decl)
2220            && (TREE_CODE (ref) == VAR_DECL
2221                || TREE_CODE (ref) == PARM_DECL
2222                || TREE_CODE (ref) == FUNCTION_DECL))
2223     {
2224       tree context = decl_function_context (ref);
2225
2226       if (context != 0 && context != current_function_decl)
2227         DECL_NONLOCAL (ref) = 1;
2228     }
2229   /* C99 6.7.4p3: An inline definition of a function with external
2230      linkage ... shall not contain a reference to an identifier with
2231      internal linkage.  */
2232   else if (current_function_decl != 0
2233            && DECL_DECLARED_INLINE_P (current_function_decl)
2234            && DECL_EXTERNAL (current_function_decl)
2235            && VAR_OR_FUNCTION_DECL_P (ref)
2236            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2237            && ! TREE_PUBLIC (ref))
2238     pedwarn ("%H%qD is static but used in inline function %qD "
2239              "which is not static", &loc, ref, current_function_decl);
2240
2241   return ref;
2242 }
2243
2244 /* Record details of decls possibly used inside sizeof or typeof.  */
2245 struct maybe_used_decl
2246 {
2247   /* The decl.  */
2248   tree decl;
2249   /* The level seen at (in_sizeof + in_typeof).  */
2250   int level;
2251   /* The next one at this level or above, or NULL.  */
2252   struct maybe_used_decl *next;
2253 };
2254
2255 static struct maybe_used_decl *maybe_used_decls;
2256
2257 /* Record that DECL, an undefined static function reference seen
2258    inside sizeof or typeof, might be used if the operand of sizeof is
2259    a VLA type or the operand of typeof is a variably modified
2260    type.  */
2261
2262 static void
2263 record_maybe_used_decl (tree decl)
2264 {
2265   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2266   t->decl = decl;
2267   t->level = in_sizeof + in_typeof;
2268   t->next = maybe_used_decls;
2269   maybe_used_decls = t;
2270 }
2271
2272 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2273    USED is false, just discard them.  If it is true, mark them used
2274    (if no longer inside sizeof or typeof) or move them to the next
2275    level up (if still inside sizeof or typeof).  */
2276
2277 void
2278 pop_maybe_used (bool used)
2279 {
2280   struct maybe_used_decl *p = maybe_used_decls;
2281   int cur_level = in_sizeof + in_typeof;
2282   while (p && p->level > cur_level)
2283     {
2284       if (used)
2285         {
2286           if (cur_level == 0)
2287             C_DECL_USED (p->decl) = 1;
2288           else
2289             p->level = cur_level;
2290         }
2291       p = p->next;
2292     }
2293   if (!used || cur_level == 0)
2294     maybe_used_decls = p;
2295 }
2296
2297 /* Return the result of sizeof applied to EXPR.  */
2298
2299 struct c_expr
2300 c_expr_sizeof_expr (struct c_expr expr)
2301 {
2302   struct c_expr ret;
2303   if (expr.value == error_mark_node)
2304     {
2305       ret.value = error_mark_node;
2306       ret.original_code = ERROR_MARK;
2307       pop_maybe_used (false);
2308     }
2309   else
2310     {
2311       ret.value = c_sizeof (TREE_TYPE (expr.value));
2312       ret.original_code = ERROR_MARK;
2313       if (c_vla_type_p (TREE_TYPE (expr.value)))
2314         {
2315           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2316           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2317         }
2318       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2319     }
2320   return ret;
2321 }
2322
2323 /* Return the result of sizeof applied to T, a structure for the type
2324    name passed to sizeof (rather than the type itself).  */
2325
2326 struct c_expr
2327 c_expr_sizeof_type (struct c_type_name *t)
2328 {
2329   tree type;
2330   struct c_expr ret;
2331   type = groktypename (t);
2332   ret.value = c_sizeof (type);
2333   ret.original_code = ERROR_MARK;
2334   pop_maybe_used (type != error_mark_node
2335                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2336   return ret;
2337 }
2338
2339 /* Build a function call to function FUNCTION with parameters PARAMS.
2340    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2341    TREE_VALUE of each node is a parameter-expression.
2342    FUNCTION's data type may be a function type or a pointer-to-function.  */
2343
2344 tree
2345 build_function_call (tree function, tree params)
2346 {
2347   tree fntype, fundecl = 0;
2348   tree name = NULL_TREE, result;
2349   tree tem;
2350   int nargs;
2351   tree *argarray;
2352
2353
2354   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2355   STRIP_TYPE_NOPS (function);
2356
2357   /* Convert anything with function type to a pointer-to-function.  */
2358   if (TREE_CODE (function) == FUNCTION_DECL)
2359     {
2360       /* Implement type-directed function overloading for builtins.
2361          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2362          handle all the type checking.  The result is a complete expression
2363          that implements this function call.  */
2364       tem = resolve_overloaded_builtin (function, params);
2365       if (tem)
2366         return tem;
2367
2368       name = DECL_NAME (function);
2369       fundecl = function;
2370     }
2371   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2372     function = function_to_pointer_conversion (function);
2373
2374   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2375      expressions, like those used for ObjC messenger dispatches.  */
2376   function = objc_rewrite_function_call (function, params);
2377
2378   fntype = TREE_TYPE (function);
2379
2380   if (TREE_CODE (fntype) == ERROR_MARK)
2381     return error_mark_node;
2382
2383   if (!(TREE_CODE (fntype) == POINTER_TYPE
2384         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2385     {
2386       error ("called object %qE is not a function", function);
2387       return error_mark_node;
2388     }
2389
2390   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2391     current_function_returns_abnormally = 1;
2392
2393   /* fntype now gets the type of function pointed to.  */
2394   fntype = TREE_TYPE (fntype);
2395
2396   /* Check that the function is called through a compatible prototype.
2397      If it is not, replace the call by a trap, wrapped up in a compound
2398      expression if necessary.  This has the nice side-effect to prevent
2399      the tree-inliner from generating invalid assignment trees which may
2400      blow up in the RTL expander later.  */
2401   if ((TREE_CODE (function) == NOP_EXPR
2402        || TREE_CODE (function) == CONVERT_EXPR)
2403       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2404       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2405       && !comptypes (fntype, TREE_TYPE (tem)))
2406     {
2407       tree return_type = TREE_TYPE (fntype);
2408       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2409                                        NULL_TREE);
2410
2411       /* This situation leads to run-time undefined behavior.  We can't,
2412          therefore, simply error unless we can prove that all possible
2413          executions of the program must execute the code.  */
2414       warning (0, "function called through a non-compatible type");
2415
2416       /* We can, however, treat "undefined" any way we please.
2417          Call abort to encourage the user to fix the program.  */
2418       inform ("if this code is reached, the program will abort");
2419
2420       if (VOID_TYPE_P (return_type))
2421         return trap;
2422       else
2423         {
2424           tree rhs;
2425
2426           if (AGGREGATE_TYPE_P (return_type))
2427             rhs = build_compound_literal (return_type,
2428                                           build_constructor (return_type, 0));
2429           else
2430             rhs = fold_convert (return_type, integer_zero_node);
2431
2432           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2433         }
2434     }
2435
2436   /* Convert the parameters to the types declared in the
2437      function prototype, or apply default promotions.  */
2438
2439   nargs = list_length (params);
2440   argarray = (tree *) alloca (nargs * sizeof (tree));
2441   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2442                              params, function, fundecl);
2443   if (nargs < 0)
2444     return error_mark_node;
2445
2446   /* Check that the arguments to the function are valid.  */
2447
2448   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2449                             TYPE_ARG_TYPES (fntype));
2450
2451   if (require_constant_value)
2452     {
2453       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2454                                                   function, nargs, argarray);
2455       if (TREE_CONSTANT (result)
2456           && (name == NULL_TREE
2457               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2458         pedwarn_init ("initializer element is not constant");
2459     }
2460   else
2461     result = fold_build_call_array (TREE_TYPE (fntype),
2462                                     function, nargs, argarray);
2463
2464   if (VOID_TYPE_P (TREE_TYPE (result)))
2465     return result;
2466   return require_complete_type (result);
2467 }
2468 \f
2469 /* Convert the argument expressions in the list VALUES
2470    to the types in the list TYPELIST.  The resulting arguments are
2471    stored in the array ARGARRAY which has size NARGS.
2472
2473    If TYPELIST is exhausted, or when an element has NULL as its type,
2474    perform the default conversions.
2475
2476    PARMLIST is the chain of parm decls for the function being called.
2477    It may be 0, if that info is not available.
2478    It is used only for generating error messages.
2479
2480    FUNCTION is a tree for the called function.  It is used only for
2481    error messages, where it is formatted with %qE.
2482
2483    This is also where warnings about wrong number of args are generated.
2484
2485    VALUES is a chain of TREE_LIST nodes with the elements of the list
2486    in the TREE_VALUE slots of those nodes.
2487
2488    Returns the actual number of arguments processed (which may be less
2489    than NARGS in some error situations), or -1 on failure.  */
2490
2491 static int
2492 convert_arguments (int nargs, tree *argarray,
2493                    tree typelist, tree values, tree function, tree fundecl)
2494 {
2495   tree typetail, valtail;
2496   int parmnum;
2497   const bool type_generic = fundecl
2498     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2499   tree selector;
2500
2501   /* Change pointer to function to the function itself for
2502      diagnostics.  */
2503   if (TREE_CODE (function) == ADDR_EXPR
2504       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2505     function = TREE_OPERAND (function, 0);
2506
2507   /* Handle an ObjC selector specially for diagnostics.  */
2508   selector = objc_message_selector ();
2509
2510   /* Scan the given expressions and types, producing individual
2511      converted arguments and storing them in ARGARRAY.  */
2512
2513   for (valtail = values, typetail = typelist, parmnum = 0;
2514        valtail;
2515        valtail = TREE_CHAIN (valtail), parmnum++)
2516     {
2517       tree type = typetail ? TREE_VALUE (typetail) : 0;
2518       tree val = TREE_VALUE (valtail);
2519       tree rname = function;
2520       int argnum = parmnum + 1;
2521       const char *invalid_func_diag;
2522
2523       if (type == void_type_node)
2524         {
2525           error ("too many arguments to function %qE", function);
2526           return parmnum;
2527         }
2528
2529       if (selector && argnum > 2)
2530         {
2531           rname = selector;
2532           argnum -= 2;
2533         }
2534
2535       STRIP_TYPE_NOPS (val);
2536
2537       val = require_complete_type (val);
2538
2539       if (type != 0)
2540         {
2541           /* Formal parm type is specified by a function prototype.  */
2542           tree parmval;
2543
2544           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2545             {
2546               error ("type of formal parameter %d is incomplete", parmnum + 1);
2547               parmval = val;
2548             }
2549           else
2550             {
2551               /* Optionally warn about conversions that
2552                  differ from the default conversions.  */
2553               if (warn_traditional_conversion || warn_traditional)
2554                 {
2555                   unsigned int formal_prec = TYPE_PRECISION (type);
2556
2557                   if (INTEGRAL_TYPE_P (type)
2558                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2559                     warning (0, "passing argument %d of %qE as integer "
2560                              "rather than floating due to prototype",
2561                              argnum, rname);
2562                   if (INTEGRAL_TYPE_P (type)
2563                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2564                     warning (0, "passing argument %d of %qE as integer "
2565                              "rather than complex due to prototype",
2566                              argnum, rname);
2567                   else if (TREE_CODE (type) == COMPLEX_TYPE
2568                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2569                     warning (0, "passing argument %d of %qE as complex "
2570                              "rather than floating due to prototype",
2571                              argnum, rname);
2572                   else if (TREE_CODE (type) == REAL_TYPE
2573                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2574                     warning (0, "passing argument %d of %qE as floating "
2575                              "rather than integer due to prototype",
2576                              argnum, rname);
2577                   else if (TREE_CODE (type) == COMPLEX_TYPE
2578                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2579                     warning (0, "passing argument %d of %qE as complex "
2580                              "rather than integer due to prototype",
2581                              argnum, rname);
2582                   else if (TREE_CODE (type) == REAL_TYPE
2583                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2584                     warning (0, "passing argument %d of %qE as floating "
2585                              "rather than complex due to prototype",
2586                              argnum, rname);
2587                   /* ??? At some point, messages should be written about
2588                      conversions between complex types, but that's too messy
2589                      to do now.  */
2590                   else if (TREE_CODE (type) == REAL_TYPE
2591                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2592                     {
2593                       /* Warn if any argument is passed as `float',
2594                          since without a prototype it would be `double'.  */
2595                       if (formal_prec == TYPE_PRECISION (float_type_node)
2596                           && type != dfloat32_type_node)
2597                         warning (0, "passing argument %d of %qE as %<float%> "
2598                                  "rather than %<double%> due to prototype",
2599                                  argnum, rname);
2600
2601                       /* Warn if mismatch between argument and prototype
2602                          for decimal float types.  Warn of conversions with
2603                          binary float types and of precision narrowing due to
2604                          prototype. */
2605                       else if (type != TREE_TYPE (val)
2606                                && (type == dfloat32_type_node
2607                                    || type == dfloat64_type_node
2608                                    || type == dfloat128_type_node
2609                                    || TREE_TYPE (val) == dfloat32_type_node
2610                                    || TREE_TYPE (val) == dfloat64_type_node
2611                                    || TREE_TYPE (val) == dfloat128_type_node)
2612                                && (formal_prec
2613                                    <= TYPE_PRECISION (TREE_TYPE (val))
2614                                    || (type == dfloat128_type_node
2615                                        && (TREE_TYPE (val)
2616                                            != dfloat64_type_node
2617                                            && (TREE_TYPE (val)
2618                                                != dfloat32_type_node)))
2619                                    || (type == dfloat64_type_node
2620                                        && (TREE_TYPE (val)
2621                                            != dfloat32_type_node))))
2622                         warning (0, "passing argument %d of %qE as %qT "
2623                                  "rather than %qT due to prototype",
2624                                  argnum, rname, type, TREE_TYPE (val));
2625
2626                     }
2627                   /* Detect integer changing in width or signedness.
2628                      These warnings are only activated with
2629                      -Wtraditional-conversion, not with -Wtraditional.  */
2630                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2631                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2632                     {
2633                       tree would_have_been = default_conversion (val);
2634                       tree type1 = TREE_TYPE (would_have_been);
2635
2636                       if (TREE_CODE (type) == ENUMERAL_TYPE
2637                           && (TYPE_MAIN_VARIANT (type)
2638                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2639                         /* No warning if function asks for enum
2640                            and the actual arg is that enum type.  */
2641                         ;
2642                       else if (formal_prec != TYPE_PRECISION (type1))
2643                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2644                                  "with different width due to prototype",
2645                                  argnum, rname);
2646                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2647                         ;
2648                       /* Don't complain if the formal parameter type
2649                          is an enum, because we can't tell now whether
2650                          the value was an enum--even the same enum.  */
2651                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2652                         ;
2653                       else if (TREE_CODE (val) == INTEGER_CST
2654                                && int_fits_type_p (val, type))
2655                         /* Change in signedness doesn't matter
2656                            if a constant value is unaffected.  */
2657                         ;
2658                       /* If the value is extended from a narrower
2659                          unsigned type, it doesn't matter whether we
2660                          pass it as signed or unsigned; the value
2661                          certainly is the same either way.  */
2662                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2663                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2664                         ;
2665                       else if (TYPE_UNSIGNED (type))
2666                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2667                                  "as unsigned due to prototype",
2668                                  argnum, rname);
2669                       else
2670                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2671                                  "as signed due to prototype", argnum, rname);
2672                     }
2673                 }
2674
2675               parmval = convert_for_assignment (type, val, ic_argpass,
2676                                                 fundecl, function,
2677                                                 parmnum + 1);
2678
2679               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2680                   && INTEGRAL_TYPE_P (type)
2681                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2682                 parmval = default_conversion (parmval);
2683             }
2684           argarray[parmnum] = parmval;
2685         }
2686       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2687                && (TYPE_PRECISION (TREE_TYPE (val))
2688                    < TYPE_PRECISION (double_type_node))
2689                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2690         {
2691           if (type_generic)
2692             argarray[parmnum] = val;
2693           else
2694             /* Convert `float' to `double'.  */
2695             argarray[parmnum] = convert (double_type_node, val);
2696         }
2697       else if ((invalid_func_diag =
2698                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2699         {
2700           error (invalid_func_diag);
2701           return -1;
2702         }
2703       else
2704         /* Convert `short' and `char' to full-size `int'.  */
2705         argarray[parmnum] = default_conversion (val);
2706
2707       if (typetail)
2708         typetail = TREE_CHAIN (typetail);
2709     }
2710
2711   gcc_assert (parmnum == nargs);
2712
2713   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2714     {
2715       error ("too few arguments to function %qE", function);
2716       return -1;
2717     }
2718
2719   return parmnum;
2720 }
2721 \f
2722 /* This is the entry point used by the parser to build unary operators
2723    in the input.  CODE, a tree_code, specifies the unary operator, and
2724    ARG is the operand.  For unary plus, the C parser currently uses
2725    CONVERT_EXPR for code.  */
2726
2727 struct c_expr
2728 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2729 {
2730   struct c_expr result;
2731
2732   result.original_code = ERROR_MARK;
2733   result.value = build_unary_op (code, arg.value, 0);
2734
2735   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2736     overflow_warning (result.value);
2737
2738   return result;
2739 }
2740
2741 /* This is the entry point used by the parser to build binary operators
2742    in the input.  CODE, a tree_code, specifies the binary operator, and
2743    ARG1 and ARG2 are the operands.  In addition to constructing the
2744    expression, we check for operands that were written with other binary
2745    operators in a way that is likely to confuse the user.  */
2746
2747 struct c_expr
2748 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2749                         struct c_expr arg2)
2750 {
2751   struct c_expr result;
2752
2753   enum tree_code code1 = arg1.original_code;
2754   enum tree_code code2 = arg2.original_code;
2755
2756   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2757   result.original_code = code;
2758
2759   if (TREE_CODE (result.value) == ERROR_MARK)
2760     return result;
2761
2762   /* Check for cases such as x+y<<z which users are likely
2763      to misinterpret.  */
2764   if (warn_parentheses)
2765     warn_about_parentheses (code, code1, code2);
2766
2767   if (code1 != tcc_comparison)
2768     warn_logical_operator (code, arg1.value, arg2.value);
2769
2770   /* Warn about comparisons against string literals, with the exception
2771      of testing for equality or inequality of a string literal with NULL.  */
2772   if (code == EQ_EXPR || code == NE_EXPR)
2773     {
2774       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2775           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2776         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2777     }
2778   else if (TREE_CODE_CLASS (code) == tcc_comparison
2779            && (code1 == STRING_CST || code2 == STRING_CST))
2780     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2781
2782   if (TREE_OVERFLOW_P (result.value)
2783       && !TREE_OVERFLOW_P (arg1.value)
2784       && !TREE_OVERFLOW_P (arg2.value))
2785     overflow_warning (result.value);
2786
2787   return result;
2788 }
2789 \f
2790 /* Return a tree for the difference of pointers OP0 and OP1.
2791    The resulting tree has type int.  */
2792
2793 static tree
2794 pointer_diff (tree op0, tree op1)
2795 {
2796   tree restype = ptrdiff_type_node;
2797
2798   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2799   tree con0, con1, lit0, lit1;
2800   tree orig_op1 = op1;
2801
2802   if (pedantic || warn_pointer_arith)
2803     {
2804       if (TREE_CODE (target_type) == VOID_TYPE)
2805         pedwarn ("pointer of type %<void *%> used in subtraction");
2806       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2807         pedwarn ("pointer to a function used in subtraction");
2808     }
2809
2810   /* If the conversion to ptrdiff_type does anything like widening or
2811      converting a partial to an integral mode, we get a convert_expression
2812      that is in the way to do any simplifications.
2813      (fold-const.c doesn't know that the extra bits won't be needed.
2814      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2815      different mode in place.)
2816      So first try to find a common term here 'by hand'; we want to cover
2817      at least the cases that occur in legal static initializers.  */
2818   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2819       && (TYPE_PRECISION (TREE_TYPE (op0))
2820           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2821     con0 = TREE_OPERAND (op0, 0);
2822   else
2823     con0 = op0;
2824   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2825       && (TYPE_PRECISION (TREE_TYPE (op1))
2826           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2827     con1 = TREE_OPERAND (op1, 0);
2828   else
2829     con1 = op1;
2830
2831   if (TREE_CODE (con0) == PLUS_EXPR)
2832     {
2833       lit0 = TREE_OPERAND (con0, 1);
2834       con0 = TREE_OPERAND (con0, 0);
2835     }
2836   else
2837     lit0 = integer_zero_node;
2838
2839   if (TREE_CODE (con1) == PLUS_EXPR)
2840     {
2841       lit1 = TREE_OPERAND (con1, 1);
2842       con1 = TREE_OPERAND (con1, 0);
2843     }
2844   else
2845     lit1 = integer_zero_node;
2846
2847   if (operand_equal_p (con0, con1, 0))
2848     {
2849       op0 = lit0;
2850       op1 = lit1;
2851     }
2852
2853
2854   /* First do the subtraction as integers;
2855      then drop through to build the divide operator.
2856      Do not do default conversions on the minus operator
2857      in case restype is a short type.  */
2858
2859   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2860                          convert (restype, op1), 0);
2861   /* This generates an error if op1 is pointer to incomplete type.  */
2862   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2863     error ("arithmetic on pointer to an incomplete type");
2864
2865   /* This generates an error if op0 is pointer to incomplete type.  */
2866   op1 = c_size_in_bytes (target_type);
2867
2868   /* Divide by the size, in easiest possible way.  */
2869   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2870 }
2871 \f
2872 /* Construct and perhaps optimize a tree representation
2873    for a unary operation.  CODE, a tree_code, specifies the operation
2874    and XARG is the operand.
2875    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2876    the default promotions (such as from short to int).
2877    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2878    allows non-lvalues; this is only used to handle conversion of non-lvalue
2879    arrays to pointers in C99.  */
2880
2881 tree
2882 build_unary_op (enum tree_code code, tree xarg, int flag)
2883 {
2884   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2885   tree arg = xarg;
2886   tree argtype = 0;
2887   enum tree_code typecode;
2888   tree val;
2889   int noconvert = flag;
2890   const char *invalid_op_diag;
2891
2892   if (code != ADDR_EXPR)
2893     arg = require_complete_type (arg);
2894
2895   typecode = TREE_CODE (TREE_TYPE (arg));
2896   if (typecode == ERROR_MARK)
2897     return error_mark_node;
2898   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2899     typecode = INTEGER_TYPE;
2900
2901   if ((invalid_op_diag
2902        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2903     {
2904       error (invalid_op_diag);
2905       return error_mark_node;
2906     }
2907
2908   switch (code)
2909     {
2910     case CONVERT_EXPR:
2911       /* This is used for unary plus, because a CONVERT_EXPR
2912          is enough to prevent anybody from looking inside for
2913          associativity, but won't generate any code.  */
2914       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2915             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2916             || typecode == VECTOR_TYPE))
2917         {
2918           error ("wrong type argument to unary plus");
2919           return error_mark_node;
2920         }
2921       else if (!noconvert)
2922         arg = default_conversion (arg);
2923       arg = non_lvalue (arg);
2924       break;
2925
2926     case NEGATE_EXPR:
2927       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2928             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2929             || typecode == VECTOR_TYPE))
2930         {
2931           error ("wrong type argument to unary minus");
2932           return error_mark_node;
2933         }
2934       else if (!noconvert)
2935         arg = default_conversion (arg);
2936       break;
2937
2938     case BIT_NOT_EXPR:
2939       /* ~ works on integer types and non float vectors. */
2940       if (typecode == INTEGER_TYPE
2941           || (typecode == VECTOR_TYPE
2942               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2943         {
2944           if (!noconvert)
2945             arg = default_conversion (arg);
2946         }
2947       else if (typecode == COMPLEX_TYPE)
2948         {
2949           code = CONJ_EXPR;
2950           if (pedantic)
2951             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2952           if (!noconvert)
2953             arg = default_conversion (arg);
2954         }
2955       else
2956         {
2957           error ("wrong type argument to bit-complement");
2958           return error_mark_node;
2959         }
2960       break;
2961
2962     case ABS_EXPR:
2963       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2964         {
2965           error ("wrong type argument to abs");
2966           return error_mark_node;
2967         }
2968       else if (!noconvert)
2969         arg = default_conversion (arg);
2970       break;
2971
2972     case CONJ_EXPR:
2973       /* Conjugating a real value is a no-op, but allow it anyway.  */
2974       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2975             || typecode == COMPLEX_TYPE))
2976         {
2977           error ("wrong type argument to conjugation");
2978           return error_mark_node;
2979         }
2980       else if (!noconvert)
2981         arg = default_conversion (arg);
2982       break;
2983
2984     case TRUTH_NOT_EXPR:
2985       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
2986           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2987           && typecode != COMPLEX_TYPE)
2988         {
2989           error ("wrong type argument to unary exclamation mark");
2990           return error_mark_node;
2991         }
2992       arg = c_objc_common_truthvalue_conversion (arg);
2993       return invert_truthvalue (arg);
2994
2995     case REALPART_EXPR:
2996       if (TREE_CODE (arg) == COMPLEX_CST)
2997         return TREE_REALPART (arg);
2998       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2999         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3000       else
3001         return arg;
3002
3003     case IMAGPART_EXPR:
3004       if (TREE_CODE (arg) == COMPLEX_CST)
3005         return TREE_IMAGPART (arg);
3006       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3007         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3008       else
3009         return convert (TREE_TYPE (arg), integer_zero_node);
3010
3011     case PREINCREMENT_EXPR:
3012     case POSTINCREMENT_EXPR:
3013     case PREDECREMENT_EXPR:
3014     case POSTDECREMENT_EXPR:
3015
3016       /* Increment or decrement the real part of the value,
3017          and don't change the imaginary part.  */
3018       if (typecode == COMPLEX_TYPE)
3019         {
3020           tree real, imag;
3021
3022           if (pedantic)
3023             pedwarn ("ISO C does not support %<++%> and %<--%>"
3024                      " on complex types");
3025
3026           arg = stabilize_reference (arg);
3027           real = build_unary_op (REALPART_EXPR, arg, 1);
3028           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3029           real = build_unary_op (code, real, 1);
3030           if (real == error_mark_node || imag == error_mark_node)
3031             return error_mark_node;
3032           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3033                          real, imag);
3034         }
3035
3036       /* Report invalid types.  */
3037
3038       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3039           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3040         {
3041           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3042             error ("wrong type argument to increment");
3043           else
3044             error ("wrong type argument to decrement");
3045
3046           return error_mark_node;
3047         }
3048
3049       {
3050         tree inc;
3051         tree result_type = TREE_TYPE (arg);
3052
3053         arg = get_unwidened (arg, 0);
3054         argtype = TREE_TYPE (arg);
3055
3056         /* Compute the increment.  */
3057
3058         if (typecode == POINTER_TYPE)
3059           {
3060             /* If pointer target is an undefined struct,
3061                we just cannot know how to do the arithmetic.  */
3062             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3063               {
3064                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3065                   error ("increment of pointer to unknown structure");
3066                 else
3067                   error ("decrement of pointer to unknown structure");
3068               }
3069             else if ((pedantic || warn_pointer_arith)
3070                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3071                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
3072               {
3073                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3074                   pedwarn ("wrong type argument to increment");
3075                 else
3076                   pedwarn ("wrong type argument to decrement");
3077               }
3078
3079             inc = c_size_in_bytes (TREE_TYPE (result_type));
3080             inc = fold_convert (sizetype, inc);
3081           }
3082         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3083           {
3084             /* For signed fract types, we invert ++ to -- or
3085                -- to ++, and change inc from 1 to -1, because
3086                it is not possible to represent 1 in signed fract constants.
3087                For unsigned fract types, the result always overflows and
3088                we get an undefined (original) or the maximum value.  */
3089             if (code == PREINCREMENT_EXPR)
3090               code = PREDECREMENT_EXPR;
3091             else if (code == PREDECREMENT_EXPR)
3092               code = PREINCREMENT_EXPR;
3093             else if (code == POSTINCREMENT_EXPR)
3094               code = POSTDECREMENT_EXPR;
3095             else /* code == POSTDECREMENT_EXPR  */
3096               code = POSTINCREMENT_EXPR;
3097
3098             inc = integer_minus_one_node;
3099             inc = convert (argtype, inc);
3100           }
3101         else
3102           {
3103             inc = integer_one_node;
3104             inc = convert (argtype, inc);
3105           }
3106
3107         /* Complain about anything else that is not a true lvalue.  */
3108         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3109                                     || code == POSTINCREMENT_EXPR)
3110                                    ? lv_increment
3111                                    : lv_decrement)))
3112           return error_mark_node;
3113
3114         /* Report a read-only lvalue.  */
3115         if (TREE_READONLY (arg))
3116           {
3117             readonly_error (arg,
3118                             ((code == PREINCREMENT_EXPR
3119                               || code == POSTINCREMENT_EXPR)
3120                              ? lv_increment : lv_decrement));
3121             return error_mark_node;
3122           }
3123
3124         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3125           val = boolean_increment (code, arg);
3126         else
3127           val = build2 (code, TREE_TYPE (arg), arg, inc);
3128         TREE_SIDE_EFFECTS (val) = 1;
3129         val = convert (result_type, val);
3130         if (TREE_CODE (val) != code)
3131           TREE_NO_WARNING (val) = 1;
3132         return val;
3133       }
3134
3135     case ADDR_EXPR:
3136       /* Note that this operation never does default_conversion.  */
3137
3138       /* Let &* cancel out to simplify resulting code.  */
3139       if (TREE_CODE (arg) == INDIRECT_REF)
3140         {
3141           /* Don't let this be an lvalue.  */
3142           if (lvalue_p (TREE_OPERAND (arg, 0)))
3143             return non_lvalue (TREE_OPERAND (arg, 0));
3144           return TREE_OPERAND (arg, 0);
3145         }
3146
3147       /* For &x[y], return x+y */
3148       if (TREE_CODE (arg) == ARRAY_REF)
3149         {
3150           tree op0 = TREE_OPERAND (arg, 0);
3151           if (!c_mark_addressable (op0))
3152             return error_mark_node;
3153           return build_binary_op (PLUS_EXPR,
3154                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3155                                    ? array_to_pointer_conversion (op0)
3156                                    : op0),
3157                                   TREE_OPERAND (arg, 1), 1);
3158         }
3159
3160       /* Anything not already handled and not a true memory reference
3161          or a non-lvalue array is an error.  */
3162       else if (typecode != FUNCTION_TYPE && !flag
3163                && !lvalue_or_else (arg, lv_addressof))
3164         return error_mark_node;
3165
3166       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3167       argtype = TREE_TYPE (arg);
3168
3169       /* If the lvalue is const or volatile, merge that into the type
3170          to which the address will point.  Note that you can't get a
3171          restricted pointer by taking the address of something, so we
3172          only have to deal with `const' and `volatile' here.  */
3173       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3174           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3175           argtype = c_build_type_variant (argtype,
3176                                           TREE_READONLY (arg),
3177                                           TREE_THIS_VOLATILE (arg));
3178
3179       if (!c_mark_addressable (arg))
3180         return error_mark_node;
3181
3182       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3183                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3184
3185       argtype = build_pointer_type (argtype);
3186
3187       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3188          when we have proper support for integer constant expressions.  */
3189       val = get_base_address (arg);
3190       if (val && TREE_CODE (val) == INDIRECT_REF
3191           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3192         {
3193           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3194
3195           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3196           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3197         }
3198
3199       val = build1 (ADDR_EXPR, argtype, arg);
3200
3201       return val;
3202
3203     default:
3204       gcc_unreachable ();
3205     }
3206
3207   if (argtype == 0)
3208     argtype = TREE_TYPE (arg);
3209   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3210                                 : fold_build1 (code, argtype, arg);
3211 }
3212
3213 /* Return nonzero if REF is an lvalue valid for this language.
3214    Lvalues can be assigned, unless their type has TYPE_READONLY.
3215    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3216
3217 static int
3218 lvalue_p (const_tree ref)
3219 {
3220   const enum tree_code code = TREE_CODE (ref);
3221
3222   switch (code)
3223     {
3224     case REALPART_EXPR:
3225     case IMAGPART_EXPR:
3226     case COMPONENT_REF:
3227       return lvalue_p (TREE_OPERAND (ref, 0));
3228
3229     case COMPOUND_LITERAL_EXPR:
3230     case STRING_CST:
3231       return 1;
3232
3233     case INDIRECT_REF:
3234     case ARRAY_REF:
3235     case VAR_DECL:
3236     case PARM_DECL:
3237     case RESULT_DECL:
3238     case ERROR_MARK:
3239       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3240               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3241
3242     case BIND_EXPR:
3243       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3244
3245     default:
3246       return 0;
3247     }
3248 }
3249 \f
3250 /* Give an error for storing in something that is 'const'.  */
3251
3252 static void
3253 readonly_error (tree arg, enum lvalue_use use)
3254 {
3255   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3256               || use == lv_asm);
3257   /* Using this macro rather than (for example) arrays of messages
3258      ensures that all the format strings are checked at compile
3259      time.  */
3260 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3261                                    : (use == lv_increment ? (I)         \
3262                                    : (use == lv_decrement ? (D) : (AS))))
3263   if (TREE_CODE (arg) == COMPONENT_REF)
3264     {
3265       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3266         readonly_error (TREE_OPERAND (arg, 0), use);
3267       else
3268         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3269                              G_("increment of read-only member %qD"),
3270                              G_("decrement of read-only member %qD"),
3271                              G_("read-only member %qD used as %<asm%> output")),
3272                TREE_OPERAND (arg, 1));
3273     }
3274   else if (TREE_CODE (arg) == VAR_DECL)
3275     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3276                          G_("increment of read-only variable %qD"),
3277                          G_("decrement of read-only variable %qD"),
3278                          G_("read-only variable %qD used as %<asm%> output")),
3279            arg);
3280   else
3281     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3282                          G_("increment of read-only location %qE"),
3283                          G_("decrement of read-only location %qE"),
3284                          G_("read-only location %qE used as %<asm%> output")),
3285            arg);
3286 }
3287
3288
3289 /* Return nonzero if REF is an lvalue valid for this language;
3290    otherwise, print an error message and return zero.  USE says
3291    how the lvalue is being used and so selects the error message.  */
3292
3293 static int
3294 lvalue_or_else (const_tree ref, enum lvalue_use use)
3295 {
3296   int win = lvalue_p (ref);
3297
3298   if (!win)
3299     lvalue_error (use);
3300
3301   return win;
3302 }
3303 \f
3304 /* Mark EXP saying that we need to be able to take the
3305    address of it; it should not be allocated in a register.
3306    Returns true if successful.  */
3307
3308 bool
3309 c_mark_addressable (tree exp)
3310 {
3311   tree x = exp;
3312
3313   while (1)
3314     switch (TREE_CODE (x))
3315       {
3316       case COMPONENT_REF:
3317         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3318           {
3319             error
3320               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3321             return false;
3322           }
3323
3324         /* ... fall through ...  */
3325
3326       case ADDR_EXPR:
3327       case ARRAY_REF:
3328       case REALPART_EXPR:
3329       case IMAGPART_EXPR:
3330         x = TREE_OPERAND (x, 0);
3331         break;
3332
3333       case COMPOUND_LITERAL_EXPR:
3334       case CONSTRUCTOR:
3335         TREE_ADDRESSABLE (x) = 1;
3336         return true;
3337
3338       case VAR_DECL:
3339       case CONST_DECL:
3340       case PARM_DECL:
3341       case RESULT_DECL:
3342         if (C_DECL_REGISTER (x)
3343             && DECL_NONLOCAL (x))
3344           {
3345             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3346               {
3347                 error
3348                   ("global register variable %qD used in nested function", x);
3349                 return false;
3350               }
3351             pedwarn ("register variable %qD used in nested function", x);
3352           }
3353         else if (C_DECL_REGISTER (x))
3354           {
3355             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3356               error ("address of global register variable %qD requested", x);
3357             else
3358               error ("address of register variable %qD requested", x);
3359             return false;
3360           }
3361
3362         /* drops in */
3363       case FUNCTION_DECL:
3364         TREE_ADDRESSABLE (x) = 1;
3365         /* drops out */
3366       default:
3367         return true;
3368     }
3369 }
3370 \f
3371 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3372
3373 tree
3374 build_conditional_expr (tree ifexp, tree op1, tree op2)
3375 {
3376   tree type1;
3377   tree type2;
3378   enum tree_code code1;
3379   enum tree_code code2;
3380   tree result_type = NULL;
3381   tree orig_op1 = op1, orig_op2 = op2;
3382
3383   /* Promote both alternatives.  */
3384
3385   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3386     op1 = default_conversion (op1);
3387   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3388     op2 = default_conversion (op2);
3389
3390   if (TREE_CODE (ifexp) == ERROR_MARK
3391       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3392       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3393     return error_mark_node;
3394
3395   type1 = TREE_TYPE (op1);
3396   code1 = TREE_CODE (type1);
3397   type2 = TREE_TYPE (op2);
3398   code2 = TREE_CODE (type2);
3399
3400   /* C90 does not permit non-lvalue arrays in conditional expressions.
3401      In C99 they will be pointers by now.  */
3402   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3403     {
3404       error ("non-lvalue array in conditional expression");
3405       return error_mark_node;
3406     }
3407
3408   /* Quickly detect the usual case where op1 and op2 have the same type
3409      after promotion.  */
3410   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3411     {
3412       if (type1 == type2)
3413         result_type = type1;
3414       else
3415         result_type = TYPE_MAIN_VARIANT (type1);
3416     }
3417   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3418             || code1 == COMPLEX_TYPE)
3419            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3420                || code2 == COMPLEX_TYPE))
3421     {
3422       result_type = c_common_type (type1, type2);
3423
3424       /* If -Wsign-compare, warn here if type1 and type2 have
3425          different signedness.  We'll promote the signed to unsigned
3426          and later code won't know it used to be different.
3427          Do this check on the original types, so that explicit casts
3428          will be considered, but default promotions won't.  */
3429       if (warn_sign_compare && !skip_evaluation)
3430         {
3431           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3432           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3433
3434           if (unsigned_op1 ^ unsigned_op2)
3435             {
3436               bool ovf;
3437
3438               /* Do not warn if the result type is signed, since the
3439                  signed type will only be chosen if it can represent
3440                  all the values of the unsigned type.  */
3441               if (!TYPE_UNSIGNED (result_type))
3442                 /* OK */;
3443               /* Do not warn if the signed quantity is an unsuffixed
3444                  integer literal (or some static constant expression
3445                  involving such literals) and it is non-negative.  */
3446               else if ((unsigned_op2
3447                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3448                        || (unsigned_op1
3449                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3450                 /* OK */;
3451               else
3452                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3453             }
3454         }
3455     }
3456   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3457     {
3458       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3459         pedwarn ("ISO C forbids conditional expr with only one void side");
3460       result_type = void_type_node;
3461     }
3462   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3463     {
3464       if (comp_target_types (type1, type2))
3465         result_type = common_pointer_type (type1, type2);
3466       else if (null_pointer_constant_p (orig_op1))
3467         result_type = qualify_type (type2, type1);
3468       else if (null_pointer_constant_p (orig_op2))
3469         result_type = qualify_type (type1, type2);
3470       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3471         {
3472           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3473             pedwarn ("ISO C forbids conditional expr between "
3474                      "%<void *%> and function pointer");
3475           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3476                                                           TREE_TYPE (type2)));
3477         }
3478       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3479         {
3480           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3481             pedwarn ("ISO C forbids conditional expr between "
3482                      "%<void *%> and function pointer");
3483           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3484                                                           TREE_TYPE (type1)));
3485         }
3486       else
3487         {
3488           pedwarn ("pointer type mismatch in conditional expression");
3489           result_type = build_pointer_type (void_type_node);
3490         }
3491     }
3492   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3493     {
3494       if (!null_pointer_constant_p (orig_op2))
3495         pedwarn ("pointer/integer type mismatch in conditional expression");
3496       else
3497         {
3498           op2 = null_pointer_node;
3499         }
3500       result_type = type1;
3501     }
3502   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3503     {
3504       if (!null_pointer_constant_p (orig_op1))
3505         pedwarn ("pointer/integer type mismatch in conditional expression");
3506       else
3507         {
3508           op1 = null_pointer_node;
3509         }
3510       result_type = type2;
3511     }
3512
3513   if (!result_type)
3514     {
3515       if (flag_cond_mismatch)
3516         result_type = void_type_node;
3517       else
3518         {
3519           error ("type mismatch in conditional expression");
3520           return error_mark_node;
3521         }
3522     }
3523
3524   /* Merge const and volatile flags of the incoming types.  */
3525   result_type
3526     = build_type_variant (result_type,
3527                           TREE_READONLY (op1) || TREE_READONLY (op2),
3528                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3529
3530   if (result_type != TREE_TYPE (op1))
3531     op1 = convert_and_check (result_type, op1);
3532   if (result_type != TREE_TYPE (op2))
3533     op2 = convert_and_check (result_type, op2);
3534
3535   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3536 }
3537 \f
3538 /* Return a compound expression that performs two expressions and
3539    returns the value of the second of them.  */
3540
3541 tree
3542 build_compound_expr (tree expr1, tree expr2)
3543 {
3544   if (!TREE_SIDE_EFFECTS (expr1))
3545     {
3546       /* The left-hand operand of a comma expression is like an expression
3547          statement: with -Wunused, we should warn if it doesn't have
3548          any side-effects, unless it was explicitly cast to (void).  */
3549       if (warn_unused_value)
3550         {
3551           if (VOID_TYPE_P (TREE_TYPE (expr1))
3552               && (TREE_CODE (expr1) == NOP_EXPR
3553                   || TREE_CODE (expr1) == CONVERT_EXPR))
3554             ; /* (void) a, b */
3555           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3556                    && TREE_CODE (expr1) == COMPOUND_EXPR
3557                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3558                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3559             ; /* (void) a, (void) b, c */
3560           else
3561             warning (OPT_Wunused_value,
3562                      "left-hand operand of comma expression has no effect");
3563         }
3564     }
3565
3566   /* With -Wunused, we should also warn if the left-hand operand does have
3567      side-effects, but computes a value which is not used.  For example, in
3568      `foo() + bar(), baz()' the result of the `+' operator is not used,
3569      so we should issue a warning.  */
3570   else if (warn_unused_value)
3571     warn_if_unused_value (expr1, input_location);
3572
3573   if (expr2 == error_mark_node)
3574     return error_mark_node;
3575
3576   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3577 }
3578
3579 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3580
3581 tree
3582 build_c_cast (tree type, tree expr)
3583 {
3584   tree value = expr;
3585
3586   if (type == error_mark_node || expr == error_mark_node)
3587     return error_mark_node;
3588
3589   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3590      only in <protocol> qualifications.  But when constructing cast expressions,
3591      the protocols do matter and must be kept around.  */
3592   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3593     return build1 (NOP_EXPR, type, expr);
3594
3595   type = TYPE_MAIN_VARIANT (type);
3596
3597   if (TREE_CODE (type) == ARRAY_TYPE)
3598     {
3599       error ("cast specifies array type");
3600       return error_mark_node;
3601     }
3602
3603   if (TREE_CODE (type) == FUNCTION_TYPE)
3604     {
3605       error ("cast specifies function type");
3606       return error_mark_node;
3607     }
3608
3609   if (!VOID_TYPE_P (type))
3610     {
3611       value = require_complete_type (value);
3612       if (value == error_mark_node)
3613         return error_mark_node;
3614     }
3615
3616   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3617     {
3618       if (pedantic)
3619         {
3620           if (TREE_CODE (type) == RECORD_TYPE
3621               || TREE_CODE (type) == UNION_TYPE)
3622             pedwarn ("ISO C forbids casting nonscalar to the same type");
3623         }
3624     }
3625   else if (TREE_CODE (type) == UNION_TYPE)
3626     {
3627       tree field;
3628
3629       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3630         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3631                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3632           break;
3633
3634       if (field)
3635         {
3636           tree t;
3637
3638           if (pedantic)
3639             pedwarn ("ISO C forbids casts to union type");
3640           t = digest_init (type,
3641                            build_constructor_single (type, field, value),
3642                            true, 0);
3643           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3644           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3645           return t;
3646         }
3647       error ("cast to union type from type not present in union");
3648       return error_mark_node;
3649     }
3650   else
3651     {
3652       tree otype, ovalue;
3653
3654       if (type == void_type_node)
3655         return build1 (CONVERT_EXPR, type, value);
3656
3657       otype = TREE_TYPE (value);
3658
3659       /* Optionally warn about potentially worrisome casts.  */
3660
3661       if (warn_cast_qual
3662           && TREE_CODE (type) == POINTER_TYPE
3663           && TREE_CODE (otype) == POINTER_TYPE)
3664         {
3665           tree in_type = type;
3666           tree in_otype = otype;
3667           int added = 0;
3668           int discarded = 0;
3669
3670           /* Check that the qualifiers on IN_TYPE are a superset of
3671              the qualifiers of IN_OTYPE.  The outermost level of
3672              POINTER_TYPE nodes is uninteresting and we stop as soon
3673              as we hit a non-POINTER_TYPE node on either type.  */
3674           do
3675             {
3676               in_otype = TREE_TYPE (in_otype);
3677               in_type = TREE_TYPE (in_type);
3678
3679               /* GNU C allows cv-qualified function types.  'const'
3680                  means the function is very pure, 'volatile' means it
3681                  can't return.  We need to warn when such qualifiers
3682                  are added, not when they're taken away.  */
3683               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3684                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3685                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3686               else
3687                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3688             }
3689           while (TREE_CODE (in_type) == POINTER_TYPE
3690                  && TREE_CODE (in_otype) == POINTER_TYPE);
3691
3692           if (added)
3693             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3694
3695           if (discarded)
3696             /* There are qualifiers present in IN_OTYPE that are not
3697                present in IN_TYPE.  */
3698             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3699         }
3700
3701       /* Warn about possible alignment problems.  */
3702       if (STRICT_ALIGNMENT
3703           && TREE_CODE (type) == POINTER_TYPE
3704           && TREE_CODE (otype) == POINTER_TYPE
3705           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3706           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3707           /* Don't warn about opaque types, where the actual alignment
3708              restriction is unknown.  */
3709           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3710                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3711                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3712           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3713         warning (OPT_Wcast_align,
3714                  "cast increases required alignment of target type");
3715
3716       if (TREE_CODE (type) == INTEGER_TYPE
3717           && TREE_CODE (otype) == POINTER_TYPE
3718           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3719       /* Unlike conversion of integers to pointers, where the
3720          warning is disabled for converting constants because
3721          of cases such as SIG_*, warn about converting constant
3722          pointers to integers. In some cases it may cause unwanted
3723          sign extension, and a warning is appropriate.  */
3724         warning (OPT_Wpointer_to_int_cast,
3725                  "cast from pointer to integer of different size");
3726
3727       if (TREE_CODE (value) == CALL_EXPR
3728           && TREE_CODE (type) != TREE_CODE (otype))
3729         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3730                  "to non-matching type %qT", otype, type);
3731
3732       if (TREE_CODE (type) == POINTER_TYPE
3733           && TREE_CODE (otype) == INTEGER_TYPE
3734           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3735           /* Don't warn about converting any constant.  */
3736           && !TREE_CONSTANT (value))
3737         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3738                  "of different size");
3739
3740       if (warn_strict_aliasing <= 2)
3741         strict_aliasing_warning (otype, type, expr);
3742
3743       /* If pedantic, warn for conversions between function and object
3744          pointer types, except for converting a null pointer constant
3745          to function pointer type.  */
3746       if (pedantic
3747           && TREE_CODE (type) == POINTER_TYPE
3748           && TREE_CODE (otype) == POINTER_TYPE
3749           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3750           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3751         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3752
3753       if (pedantic
3754           && TREE_CODE (type) == POINTER_TYPE
3755           && TREE_CODE (otype) == POINTER_TYPE
3756           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3757           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3758           && !null_pointer_constant_p (value))
3759         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3760
3761       ovalue = value;
3762       value = convert (type, value);
3763
3764       /* Ignore any integer overflow caused by the cast.  */
3765       if (TREE_CODE (value) == INTEGER_CST)
3766         {
3767           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3768             {
3769               if (!TREE_OVERFLOW (value))
3770                 {
3771                   /* Avoid clobbering a shared constant.  */
3772                   value = copy_node (value);
3773                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3774                 }
3775             }
3776           else if (TREE_OVERFLOW (value))
3777             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3778             value = build_int_cst_wide (TREE_TYPE (value),
3779                                         TREE_INT_CST_LOW (value),
3780                                         TREE_INT_CST_HIGH (value));
3781         }
3782     }
3783
3784   /* Don't let a cast be an lvalue.  */
3785   if (value == expr)
3786     value = non_lvalue (value);
3787
3788   return value;
3789 }
3790
3791 /* Interpret a cast of expression EXPR to type TYPE.  */
3792 tree
3793 c_cast_expr (struct c_type_name *type_name, tree expr)
3794 {
3795   tree type;
3796   int saved_wsp = warn_strict_prototypes;
3797
3798   /* This avoids warnings about unprototyped casts on
3799      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3800   if (TREE_CODE (expr) == INTEGER_CST)
3801     warn_strict_prototypes = 0;
3802   type = groktypename (type_name);
3803   warn_strict_prototypes = saved_wsp;
3804
3805   return build_c_cast (type, expr);
3806 }
3807 \f
3808 /* Build an assignment expression of lvalue LHS from value RHS.
3809    MODIFYCODE is the code for a binary operator that we use
3810    to combine the old value of LHS with RHS to get the new value.
3811    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3812
3813 tree
3814 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3815 {
3816   tree result;
3817   tree newrhs;
3818   tree lhstype = TREE_TYPE (lhs);
3819   tree olhstype = lhstype;
3820
3821   /* Types that aren't fully specified cannot be used in assignments.  */
3822   lhs = require_complete_type (lhs);
3823
3824   /* Avoid duplicate error messages from operands that had errors.  */
3825   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3826     return error_mark_node;
3827
3828   if (!lvalue_or_else (lhs, lv_assign))
3829     return error_mark_node;
3830
3831   STRIP_TYPE_NOPS (rhs);
3832
3833   newrhs = rhs;
3834
3835   /* If a binary op has been requested, combine the old LHS value with the RHS
3836      producing the value we should actually store into the LHS.  */
3837
3838   if (modifycode != NOP_EXPR)
3839     {
3840       lhs = stabilize_reference (lhs);
3841       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3842     }
3843
3844   /* Give an error for storing in something that is 'const'.  */
3845
3846   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3847       || ((TREE_CODE (lhstype) == RECORD_TYPE
3848            || TREE_CODE (lhstype) == UNION_TYPE)
3849           && C_TYPE_FIELDS_READONLY (lhstype)))
3850     {
3851       readonly_error (lhs, lv_assign);
3852       return error_mark_node;
3853     }
3854
3855   /* If storing into a structure or union member,
3856      it has probably been given type `int'.
3857      Compute the type that would go with
3858      the actual amount of storage the member occupies.  */
3859
3860   if (TREE_CODE (lhs) == COMPONENT_REF
3861       && (TREE_CODE (lhstype) == INTEGER_TYPE
3862           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3863           || TREE_CODE (lhstype) == REAL_TYPE
3864           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3865     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3866
3867   /* If storing in a field that is in actuality a short or narrower than one,
3868      we must store in the field in its actual type.  */
3869
3870   if (lhstype != TREE_TYPE (lhs))
3871     {
3872       lhs = copy_node (lhs);
3873       TREE_TYPE (lhs) = lhstype;
3874     }
3875
3876   /* Convert new value to destination type.  */
3877
3878   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3879                                    NULL_TREE, NULL_TREE, 0);
3880   if (TREE_CODE (newrhs) == ERROR_MARK)
3881     return error_mark_node;
3882
3883   /* Emit ObjC write barrier, if necessary.  */
3884   if (c_dialect_objc () && flag_objc_gc)
3885     {
3886       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3887       if (result)
3888         return result;
3889     }
3890
3891   /* Scan operands.  */
3892
3893   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3894   TREE_SIDE_EFFECTS (result) = 1;
3895
3896   /* If we got the LHS in a different type for storing in,
3897      convert the result back to the nominal type of LHS
3898      so that the value we return always has the same type
3899      as the LHS argument.  */
3900
3901   if (olhstype == TREE_TYPE (result))
3902     return result;
3903   return convert_for_assignment (olhstype, result, ic_assign,
3904                                  NULL_TREE, NULL_TREE, 0);
3905 }
3906 \f
3907 /* Convert value RHS to type TYPE as preparation for an assignment
3908    to an lvalue of type TYPE.
3909    The real work of conversion is done by `convert'.
3910    The purpose of this function is to generate error messages
3911    for assignments that are not allowed in C.
3912    ERRTYPE says whether it is argument passing, assignment,
3913    initialization or return.
3914
3915    FUNCTION is a tree for the function being called.
3916    PARMNUM is the number of the argument, for printing in error messages.  */
3917
3918 static tree
3919 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3920                         tree fundecl, tree function, int parmnum)
3921 {
3922   enum tree_code codel = TREE_CODE (type);
3923   tree rhstype;
3924   enum tree_code coder;
3925   tree rname = NULL_TREE;
3926   bool objc_ok = false;
3927
3928   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3929     {
3930       tree selector;
3931       /* Change pointer to function to the function itself for
3932          diagnostics.  */
3933       if (TREE_CODE (function) == ADDR_EXPR
3934           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3935         function = TREE_OPERAND (function, 0);
3936
3937       /* Handle an ObjC selector specially for diagnostics.  */
3938       selector = objc_message_selector ();
3939       rname = function;
3940       if (selector && parmnum > 2)
3941         {
3942           rname = selector;
3943           parmnum -= 2;
3944         }
3945     }
3946
3947   /* This macro is used to emit diagnostics to ensure that all format
3948      strings are complete sentences, visible to gettext and checked at
3949      compile time.  */
3950 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3951   do {                                          \
3952     switch (errtype)                            \
3953       {                                         \
3954       case ic_argpass:                          \
3955         pedwarn (AR, parmnum, rname);           \
3956         break;                                  \
3957       case ic_argpass_nonproto:                 \
3958         warning (0, AR, parmnum, rname);                \
3959         break;                                  \
3960       case ic_assign:                           \
3961         pedwarn (AS);                           \
3962         break;                                  \
3963       case ic_init:                             \
3964         pedwarn (IN);                           \
3965         break;                                  \
3966       case ic_return:                           \
3967         pedwarn (RE);                           \
3968         break;                                  \
3969       default:                                  \
3970         gcc_unreachable ();                     \
3971       }                                         \
3972   } while (0)
3973
3974   STRIP_TYPE_NOPS (rhs);
3975
3976   if (optimize && TREE_CODE (rhs) == VAR_DECL
3977            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3978     rhs = decl_constant_value_for_broken_optimization (rhs);
3979
3980   rhstype = TREE_TYPE (rhs);
3981   coder = TREE_CODE (rhstype);
3982
3983   if (coder == ERROR_MARK)
3984     return error_mark_node;
3985
3986   if (c_dialect_objc ())
3987     {
3988       int parmno;
3989
3990       switch (errtype)
3991         {
3992         case ic_return:
3993           parmno = 0;
3994           break;
3995
3996         case ic_assign:
3997           parmno = -1;
3998           break;
3999
4000         case ic_init:
4001           parmno = -2;
4002           break;
4003
4004         default:
4005           parmno = parmnum;
4006           break;
4007         }
4008
4009       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4010     }
4011
4012   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4013     return rhs;
4014
4015   if (coder == VOID_TYPE)
4016     {
4017       /* Except for passing an argument to an unprototyped function,
4018          this is a constraint violation.  When passing an argument to
4019          an unprototyped function, it is compile-time undefined;
4020          making it a constraint in that case was rejected in
4021          DR#252.  */
4022       error ("void value not ignored as it ought to be");
4023       return error_mark_node;
4024     }
4025   rhs = require_complete_type (rhs);
4026   if (rhs == error_mark_node)
4027     return error_mark_node;
4028   /* A type converts to a reference to it.
4029      This code doesn't fully support references, it's just for the
4030      special case of va_start and va_copy.  */
4031   if (codel == REFERENCE_TYPE
4032       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4033     {
4034       if (!lvalue_p (rhs))
4035         {
4036           error ("cannot pass rvalue to reference parameter");
4037           return error_mark_node;
4038         }
4039       if (!c_mark_addressable (rhs))
4040         return error_mark_node;
4041       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4042
4043       /* We already know that these two types are compatible, but they
4044          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4045          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4046          likely to be va_list, a typedef to __builtin_va_list, which
4047          is different enough that it will cause problems later.  */
4048       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4049         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4050
4051       rhs = build1 (NOP_EXPR, type, rhs);
4052       return rhs;
4053     }
4054   /* Some types can interconvert without explicit casts.  */
4055   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4056            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4057     return convert (type, rhs);
4058   /* Arithmetic types all interconvert, and enum is treated like int.  */
4059   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4060             || codel == FIXED_POINT_TYPE
4061             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4062             || codel == BOOLEAN_TYPE)
4063            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4064                || coder == FIXED_POINT_TYPE
4065                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4066                || coder == BOOLEAN_TYPE))
4067     return convert_and_check (type, rhs);
4068
4069   /* Aggregates in different TUs might need conversion.  */
4070   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4071       && codel == coder
4072       && comptypes (type, rhstype))
4073     return convert_and_check (type, rhs);
4074
4075   /* Conversion to a transparent union from its member types.
4076      This applies only to function arguments.  */
4077   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4078       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4079     {
4080       tree memb, marginal_memb = NULL_TREE;
4081
4082       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4083         {
4084           tree memb_type = TREE_TYPE (memb);
4085
4086           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4087                          TYPE_MAIN_VARIANT (rhstype)))
4088             break;
4089
4090           if (TREE_CODE (memb_type) != POINTER_TYPE)
4091             continue;
4092
4093           if (coder == POINTER_TYPE)
4094             {
4095               tree ttl = TREE_TYPE (memb_type);
4096               tree ttr = TREE_TYPE (rhstype);
4097
4098               /* Any non-function converts to a [const][volatile] void *
4099                  and vice versa; otherwise, targets must be the same.
4100                  Meanwhile, the lhs target must have all the qualifiers of
4101                  the rhs.  */
4102               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4103                   || comp_target_types (memb_type, rhstype))
4104                 {
4105                   /* If this type won't generate any warnings, use it.  */
4106                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4107                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4108                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4109                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4110                              == TYPE_QUALS (ttr))
4111                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4112                              == TYPE_QUALS (ttl))))
4113                     break;
4114
4115                   /* Keep looking for a better type, but remember this one.  */
4116                   if (!marginal_memb)
4117                     marginal_memb = memb;
4118                 }
4119             }
4120
4121           /* Can convert integer zero to any pointer type.  */
4122           if (null_pointer_constant_p (rhs))
4123             {
4124               rhs = null_pointer_node;
4125               break;
4126             }
4127         }
4128
4129       if (memb || marginal_memb)
4130         {
4131           if (!memb)
4132             {
4133               /* We have only a marginally acceptable member type;
4134                  it needs a warning.  */
4135               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4136               tree ttr = TREE_TYPE (rhstype);
4137
4138               /* Const and volatile mean something different for function
4139                  types, so the usual warnings are not appropriate.  */
4140               if (TREE_CODE (ttr) == FUNCTION_TYPE
4141                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4142                 {
4143                   /* Because const and volatile on functions are
4144                      restrictions that say the function will not do
4145                      certain things, it is okay to use a const or volatile
4146                      function where an ordinary one is wanted, but not
4147                      vice-versa.  */
4148                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4149                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4150                                             "makes qualified function "
4151                                             "pointer from unqualified"),
4152                                          G_("assignment makes qualified "
4153                                             "function pointer from "
4154                                             "unqualified"),
4155                                          G_("initialization makes qualified "
4156                                             "function pointer from "
4157                                             "unqualified"),
4158                                          G_("return makes qualified function "
4159                                             "pointer from unqualified"));
4160                 }
4161               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4162                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4163                                         "qualifiers from pointer target type"),
4164                                      G_("assignment discards qualifiers "
4165                                         "from pointer target type"),
4166                                      G_("initialization discards qualifiers "
4167                                         "from pointer target type"),
4168                                      G_("return discards qualifiers from "
4169                                         "pointer target type"));
4170
4171               memb = marginal_memb;
4172             }
4173
4174           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4175             pedwarn ("ISO C prohibits argument conversion to union type");
4176
4177           rhs = fold_convert (TREE_TYPE (memb), rhs);
4178           return build_constructor_single (type, memb, rhs);
4179         }
4180     }
4181
4182   /* Conversions among pointers */
4183   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4184            && (coder == codel))
4185     {
4186       tree ttl = TREE_TYPE (type);
4187       tree ttr = TREE_TYPE (rhstype);
4188       tree mvl = ttl;
4189       tree mvr = ttr;
4190       bool is_opaque_pointer;
4191       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4192
4193       if (TREE_CODE (mvl) != ARRAY_TYPE)
4194         mvl = TYPE_MAIN_VARIANT (mvl);
4195       if (TREE_CODE (mvr) != ARRAY_TYPE)
4196         mvr = TYPE_MAIN_VARIANT (mvr);
4197       /* Opaque pointers are treated like void pointers.  */
4198       is_opaque_pointer = (targetm.vector_opaque_p (type)
4199                            || targetm.vector_opaque_p (rhstype))
4200         && TREE_CODE (ttl) == VECTOR_TYPE
4201         && TREE_CODE (ttr) == VECTOR_TYPE;
4202
4203       /* C++ does not allow the implicit conversion void* -> T*.  However,
4204          for the purpose of reducing the number of false positives, we
4205          tolerate the special case of
4206
4207                 int *p = NULL;
4208
4209          where NULL is typically defined in C to be '(void *) 0'.  */
4210       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4211         warning (OPT_Wc___compat, "request for implicit conversion from "
4212                  "%qT to %qT not permitted in C++", rhstype, type);
4213
4214       /* Check if the right-hand side has a format attribute but the
4215          left-hand side doesn't.  */
4216       if (warn_missing_format_attribute
4217           && check_missing_format_attribute (type, rhstype))
4218         {
4219           switch (errtype)
4220           {
4221           case ic_argpass:
4222           case ic_argpass_nonproto:
4223             warning (OPT_Wmissing_format_attribute,
4224                      "argument %d of %qE might be "
4225                      "a candidate for a format attribute",
4226                      parmnum, rname);
4227             break;
4228           case ic_assign:
4229             warning (OPT_Wmissing_format_attribute,
4230                      "assignment left-hand side might be "
4231                      "a candidate for a format attribute");
4232             break;
4233           case ic_init:
4234             warning (OPT_Wmissing_format_attribute,
4235                      "initialization left-hand side might be "
4236                      "a candidate for a format attribute");
4237             break;
4238           case ic_return:
4239             warning (OPT_Wmissing_format_attribute,
4240                      "return type might be "
4241                      "a candidate for a format attribute");
4242             break;
4243           default:
4244             gcc_unreachable ();
4245           }
4246         }
4247
4248       /* Any non-function converts to a [const][volatile] void *
4249          and vice versa; otherwise, targets must be the same.
4250          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4251       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4252           || (target_cmp = comp_target_types (type, rhstype))
4253           || is_opaque_pointer
4254           || (c_common_unsigned_type (mvl)
4255               == c_common_unsigned_type (mvr)))
4256         {
4257           if (pedantic
4258               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4259                   ||
4260                   (VOID_TYPE_P (ttr)
4261                    && !null_pointer_constant_p (rhs)
4262                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4263             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4264                                     "%qE between function pointer "
4265                                     "and %<void *%>"),
4266                                  G_("ISO C forbids assignment between "
4267                                     "function pointer and %<void *%>"),
4268                                  G_("ISO C forbids initialization between "
4269                                     "function pointer and %<void *%>"),
4270                                  G_("ISO C forbids return between function "
4271                                     "pointer and %<void *%>"));
4272           /* Const and volatile mean something different for function types,
4273              so the usual warnings are not appropriate.  */
4274           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4275                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4276             {
4277               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4278                 {
4279                   /* Types differing only by the presence of the 'volatile'
4280                      qualifier are acceptable if the 'volatile' has been added
4281                      in by the Objective-C EH machinery.  */
4282                   if (!objc_type_quals_match (ttl, ttr))
4283                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4284                                             "qualifiers from pointer target type"),
4285                                          G_("assignment discards qualifiers "
4286                                             "from pointer target type"),
4287                                          G_("initialization discards qualifiers "
4288                                             "from pointer target type"),
4289                                          G_("return discards qualifiers from "
4290                                             "pointer target type"));
4291                 }
4292               /* If this is not a case of ignoring a mismatch in signedness,
4293                  no warning.  */
4294               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4295                        || target_cmp)
4296                 ;
4297               /* If there is a mismatch, do warn.  */
4298               else if (warn_pointer_sign)
4299                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4300                                         "%d of %qE differ in signedness"),
4301                                      G_("pointer targets in assignment "
4302                                         "differ in signedness"),
4303                                      G_("pointer targets in initialization "
4304                                         "differ in signedness"),
4305                                      G_("pointer targets in return differ "
4306                                         "in signedness"));
4307             }
4308           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4309                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4310             {
4311               /* Because const and volatile on functions are restrictions
4312                  that say the function will not do certain things,
4313                  it is okay to use a const or volatile function
4314                  where an ordinary one is wanted, but not vice-versa.  */
4315               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4316                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4317                                         "qualified function pointer "
4318                                         "from unqualified"),
4319                                      G_("assignment makes qualified function "
4320                                         "pointer from unqualified"),
4321                                      G_("initialization makes qualified "
4322                                         "function pointer from unqualified"),
4323                                      G_("return makes qualified function "
4324                                         "pointer from unqualified"));
4325             }
4326         }
4327       else
4328         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4329         if (!objc_ok)
4330           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4331                                   "incompatible pointer type"),
4332                                G_("assignment from incompatible pointer type"),
4333                                G_("initialization from incompatible "
4334                                   "pointer type"),
4335                                G_("return from incompatible pointer type"));
4336
4337       return convert (type, rhs);
4338     }
4339   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4340     {
4341       /* ??? This should not be an error when inlining calls to
4342          unprototyped functions.  */
4343       error ("invalid use of non-lvalue array");
4344       return error_mark_node;
4345     }
4346   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4347     {
4348       /* An explicit constant 0 can convert to a pointer,
4349          or one that results from arithmetic, even including
4350          a cast to integer type.  */
4351       if (!null_pointer_constant_p (rhs))
4352         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4353                                 "pointer from integer without a cast"),
4354                              G_("assignment makes pointer from integer "
4355                                 "without a cast"),
4356                              G_("initialization makes pointer from "
4357                                 "integer without a cast"),
4358                              G_("return makes pointer from integer "
4359                                 "without a cast"));
4360
4361       return convert (type, rhs);
4362     }
4363   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4364     {
4365       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4366                               "from pointer without a cast"),
4367                            G_("assignment makes integer from pointer "
4368                               "without a cast"),
4369                            G_("initialization makes integer from pointer "
4370                               "without a cast"),
4371                            G_("return makes integer from pointer "
4372                               "without a cast"));
4373       return convert (type, rhs);
4374     }
4375   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4376     return convert (type, rhs);
4377
4378   switch (errtype)
4379     {
4380     case ic_argpass:
4381     case ic_argpass_nonproto:
4382       /* ??? This should not be an error when inlining calls to
4383          unprototyped functions.  */
4384       error ("incompatible type for argument %d of %qE", parmnum, rname);
4385       break;
4386     case ic_assign:
4387       error ("incompatible types in assignment");
4388       break;
4389     case ic_init:
4390       error ("incompatible types in initialization");
4391       break;
4392     case ic_return:
4393       error ("incompatible types in return");
4394       break;
4395     default:
4396       gcc_unreachable ();
4397     }
4398
4399   return error_mark_node;
4400 }
4401 \f
4402 /* If VALUE is a compound expr all of whose expressions are constant, then
4403    return its value.  Otherwise, return error_mark_node.
4404
4405    This is for handling COMPOUND_EXPRs as initializer elements
4406    which is allowed with a warning when -pedantic is specified.  */
4407
4408 static tree
4409 valid_compound_expr_initializer (tree value, tree endtype)
4410 {
4411   if (TREE_CODE (value) == COMPOUND_EXPR)
4412     {
4413       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4414           == error_mark_node)
4415         return error_mark_node;
4416       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4417                                               endtype);
4418     }
4419   else if (!initializer_constant_valid_p (value, endtype))
4420     return error_mark_node;
4421   else
4422     return value;
4423 }
4424 \f
4425 /* Perform appropriate conversions on the initial value of a variable,
4426    store it in the declaration DECL,
4427    and print any error messages that are appropriate.
4428    If the init is invalid, store an ERROR_MARK.  */
4429
4430 void
4431 store_init_value (tree decl, tree init)
4432 {
4433   tree value, type;
4434
4435   /* If variable's type was invalidly declared, just ignore it.  */
4436
4437   type = TREE_TYPE (decl);
4438   if (TREE_CODE (type) == ERROR_MARK)
4439     return;
4440
4441   /* Digest the specified initializer into an expression.  */
4442
4443   value = digest_init (type, init, true, TREE_STATIC (decl));
4444
4445   /* Store the expression if valid; else report error.  */
4446
4447   if (!in_system_header
4448       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4449     warning (OPT_Wtraditional, "traditional C rejects automatic "
4450              "aggregate initialization");
4451
4452   DECL_INITIAL (decl) = value;
4453
4454   /* ANSI wants warnings about out-of-range constant initializers.  */
4455   STRIP_TYPE_NOPS (value);
4456   if (TREE_STATIC (decl))
4457     constant_expression_warning (value);
4458
4459   /* Check if we need to set array size from compound literal size.  */
4460   if (TREE_CODE (type) == ARRAY_TYPE
4461       && TYPE_DOMAIN (type) == 0
4462       && value != error_mark_node)
4463     {
4464       tree inside_init = init;
4465
4466       STRIP_TYPE_NOPS (inside_init);
4467       inside_init = fold (inside_init);
4468
4469       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4470         {
4471           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4472
4473           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4474             {
4475               /* For int foo[] = (int [3]){1}; we need to set array size
4476                  now since later on array initializer will be just the
4477                  brace enclosed list of the compound literal.  */
4478               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4479               TREE_TYPE (decl) = type;
4480               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4481               layout_type (type);
4482               layout_decl (cldecl, 0);
4483             }
4484         }
4485     }
4486 }
4487 \f
4488 /* Methods for storing and printing names for error messages.  */
4489
4490 /* Implement a spelling stack that allows components of a name to be pushed
4491    and popped.  Each element on the stack is this structure.  */
4492
4493 struct spelling
4494 {
4495   int kind;
4496   union
4497     {
4498       unsigned HOST_WIDE_INT i;
4499       const char *s;
4500     } u;
4501 };
4502
4503 #define SPELLING_STRING 1
4504 #define SPELLING_MEMBER 2
4505 #define SPELLING_BOUNDS 3
4506
4507 static struct spelling *spelling;       /* Next stack element (unused).  */
4508 static struct spelling *spelling_base;  /* Spelling stack base.  */
4509 static int spelling_size;               /* Size of the spelling stack.  */
4510
4511 /* Macros to save and restore the spelling stack around push_... functions.
4512    Alternative to SAVE_SPELLING_STACK.  */
4513
4514 #define SPELLING_DEPTH() (spelling - spelling_base)
4515 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4516
4517 /* Push an element on the spelling stack with type KIND and assign VALUE
4518    to MEMBER.  */
4519
4520 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4521 {                                                                       \
4522   int depth = SPELLING_DEPTH ();                                        \
4523                                                                         \
4524   if (depth >= spelling_size)                                           \
4525     {                                                                   \
4526       spelling_size += 10;                                              \
4527       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4528                                   spelling_size);                       \
4529       RESTORE_SPELLING_DEPTH (depth);                                   \
4530     }                                                                   \
4531                                                                         \
4532   spelling->kind = (KIND);                                              \
4533   spelling->MEMBER = (VALUE);                                           \
4534   spelling++;                                                           \
4535 }
4536
4537 /* Push STRING on the stack.  Printed literally.  */
4538
4539 static void
4540 push_string (const char *string)
4541 {
4542   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4543 }
4544
4545 /* Push a member name on the stack.  Printed as '.' STRING.  */
4546
4547 static void
4548 push_member_name (tree decl)
4549 {
4550   const char *const string
4551     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4552   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4553 }
4554
4555 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4556
4557 static void
4558 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4559 {
4560   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4561 }
4562
4563 /* Compute the maximum size in bytes of the printed spelling.  */
4564
4565 static int
4566 spelling_length (void)
4567 {
4568   int size = 0;
4569   struct spelling *p;
4570
4571   for (p = spelling_base; p < spelling; p++)
4572     {
4573       if (p->kind == SPELLING_BOUNDS)
4574         size += 25;
4575       else
4576         size += strlen (p->u.s) + 1;
4577     }
4578
4579   return size;
4580 }
4581
4582 /* Print the spelling to BUFFER and return it.  */
4583
4584 static char *
4585 print_spelling (char *buffer)
4586 {
4587   char *d = buffer;
4588   struct spelling *p;
4589
4590   for (p = spelling_base; p < spelling; p++)
4591     if (p->kind == SPELLING_BOUNDS)
4592       {
4593         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4594         d += strlen (d);
4595       }
4596     else
4597       {
4598         const char *s;
4599         if (p->kind == SPELLING_MEMBER)
4600           *d++ = '.';
4601         for (s = p->u.s; (*d = *s++); d++)
4602           ;
4603       }
4604   *d++ = '\0';
4605   return buffer;
4606 }
4607
4608 /* Issue an error message for a bad initializer component.
4609    MSGID identifies the message.
4610    The component name is taken from the spelling stack.  */
4611
4612 void
4613 error_init (const char *msgid)
4614 {
4615   char *ofwhat;
4616
4617   error ("%s", _(msgid));
4618   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4619   if (*ofwhat)
4620     error ("(near initialization for %qs)", ofwhat);
4621 }
4622
4623 /* Issue a pedantic warning for a bad initializer component.
4624    MSGID identifies the message.
4625    The component name is taken from the spelling stack.  */
4626
4627 void
4628 pedwarn_init (const char *msgid)
4629 {
4630   char *ofwhat;
4631
4632   pedwarn ("%s", _(msgid));
4633   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4634   if (*ofwhat)
4635     pedwarn ("(near initialization for %qs)", ofwhat);
4636 }
4637
4638 /* Issue a warning for a bad initializer component.
4639    MSGID identifies the message.
4640    The component name is taken from the spelling stack.  */
4641
4642 static void
4643 warning_init (const char *msgid)
4644 {
4645   char *ofwhat;
4646
4647   warning (0, "%s", _(msgid));
4648   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4649   if (*ofwhat)
4650     warning (0, "(near initialization for %qs)", ofwhat);
4651 }
4652 \f
4653 /* If TYPE is an array type and EXPR is a parenthesized string
4654    constant, warn if pedantic that EXPR is being used to initialize an
4655    object of type TYPE.  */
4656
4657 void
4658 maybe_warn_string_init (tree type, struct c_expr expr)
4659 {
4660   if (pedantic
4661       && TREE_CODE (type) == ARRAY_TYPE
4662       && TREE_CODE (expr.value) == STRING_CST
4663       && expr.original_code != STRING_CST)
4664     pedwarn_init ("array initialized from parenthesized string constant");
4665 }
4666
4667 /* Digest the parser output INIT as an initializer for type TYPE.
4668    Return a C expression of type TYPE to represent the initial value.
4669
4670    If INIT is a string constant, STRICT_STRING is true if it is
4671    unparenthesized or we should not warn here for it being parenthesized.
4672    For other types of INIT, STRICT_STRING is not used.
4673
4674    REQUIRE_CONSTANT requests an error if non-constant initializers or
4675    elements are seen.  */
4676
4677 static tree
4678 digest_init (tree type, tree init, bool strict_string, int require_constant)
4679 {
4680   enum tree_code code = TREE_CODE (type);
4681   tree inside_init = init;
4682
4683   if (type == error_mark_node
4684       || !init
4685       || init == error_mark_node
4686       || TREE_TYPE (init) == error_mark_node)
4687     return error_mark_node;
4688
4689   STRIP_TYPE_NOPS (inside_init);
4690
4691   inside_init = fold (inside_init);
4692
4693   /* Initialization of an array of chars from a string constant
4694      optionally enclosed in braces.  */
4695
4696   if (code == ARRAY_TYPE && inside_init
4697       && TREE_CODE (inside_init) == STRING_CST)
4698     {
4699       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4700       /* Note that an array could be both an array of character type
4701          and an array of wchar_t if wchar_t is signed char or unsigned
4702          char.  */
4703       bool char_array = (typ1 == char_type_node
4704                          || typ1 == signed_char_type_node
4705                          || typ1 == unsigned_char_type_node);
4706       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4707       if (char_array || wchar_array)
4708         {
4709           struct c_expr expr;
4710           bool char_string;
4711           expr.value = inside_init;
4712           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4713           maybe_warn_string_init (type, expr);
4714
4715           char_string
4716             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4717                == char_type_node);
4718
4719           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4720                          TYPE_MAIN_VARIANT (type)))
4721             return inside_init;
4722
4723           if (!wchar_array && !char_string)
4724             {
4725               error_init ("char-array initialized from wide string");
4726               return error_mark_node;
4727             }
4728           if (char_string && !char_array)
4729             {
4730               error_init ("wchar_t-array initialized from non-wide string");
4731               return error_mark_node;
4732             }
4733
4734           TREE_TYPE (inside_init) = type;
4735           if (TYPE_DOMAIN (type) != 0
4736               && TYPE_SIZE (type) != 0
4737               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4738               /* Subtract 1 (or sizeof (wchar_t))
4739                  because it's ok to ignore the terminating null char
4740                  that is counted in the length of the constant.  */
4741               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4742                                        TREE_STRING_LENGTH (inside_init)
4743                                        - ((TYPE_PRECISION (typ1)
4744                                            != TYPE_PRECISION (char_type_node))
4745                                           ? (TYPE_PRECISION (wchar_type_node)
4746                                              / BITS_PER_UNIT)
4747                                           : 1)))
4748             pedwarn_init ("initializer-string for array of chars is too long");
4749
4750           return inside_init;
4751         }
4752       else if (INTEGRAL_TYPE_P (typ1))
4753         {
4754           error_init ("array of inappropriate type initialized "
4755                       "from string constant");
4756           return error_mark_node;
4757         }
4758     }
4759
4760   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4761      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4762      below and handle as a constructor.  */
4763   if (code == VECTOR_TYPE
4764       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4765       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4766       && TREE_CONSTANT (inside_init))
4767     {
4768       if (TREE_CODE (inside_init) == VECTOR_CST
4769           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4770                         TYPE_MAIN_VARIANT (type)))
4771         return inside_init;
4772
4773       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4774         {
4775           unsigned HOST_WIDE_INT ix;
4776           tree value;
4777           bool constant_p = true;
4778
4779           /* Iterate through elements and check if all constructor
4780              elements are *_CSTs.  */
4781           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4782             if (!CONSTANT_CLASS_P (value))
4783               {
4784                 constant_p = false;
4785                 break;
4786               }
4787
4788           if (constant_p)
4789             return build_vector_from_ctor (type,
4790                                            CONSTRUCTOR_ELTS (inside_init));
4791         }
4792     }
4793
4794   /* Any type can be initialized
4795      from an expression of the same type, optionally with braces.  */
4796
4797   if (inside_init && TREE_TYPE (inside_init) != 0
4798       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4799                      TYPE_MAIN_VARIANT (type))
4800           || (code == ARRAY_TYPE
4801               && comptypes (TREE_TYPE (inside_init), type))
4802           || (code == VECTOR_TYPE
4803               && comptypes (TREE_TYPE (inside_init), type))
4804           || (code == POINTER_TYPE
4805               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4806               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4807                             TREE_TYPE (type)))))
4808     {
4809       if (code == POINTER_TYPE)
4810         {
4811           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4812             {
4813               if (TREE_CODE (inside_init) == STRING_CST
4814                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4815                 inside_init = array_to_pointer_conversion (inside_init);
4816               else
4817                 {
4818                   error_init ("invalid use of non-lvalue array");
4819                   return error_mark_node;
4820                 }
4821             }
4822         }
4823
4824       if (code == VECTOR_TYPE)
4825         /* Although the types are compatible, we may require a
4826            conversion.  */
4827         inside_init = convert (type, inside_init);
4828
4829       if (require_constant
4830           && (code == VECTOR_TYPE || !flag_isoc99)
4831           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4832         {
4833           /* As an extension, allow initializing objects with static storage
4834              duration with compound literals (which are then treated just as
4835              the brace enclosed list they contain).  Also allow this for
4836              vectors, as we can only assign them with compound literals.  */
4837           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4838           inside_init = DECL_INITIAL (decl);
4839         }
4840
4841       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4842           && TREE_CODE (inside_init) != CONSTRUCTOR)
4843         {
4844           error_init ("array initialized from non-constant array expression");
4845           return error_mark_node;
4846         }
4847
4848       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4849         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4850
4851       /* Compound expressions can only occur here if -pedantic or
4852          -pedantic-errors is specified.  In the later case, we always want
4853          an error.  In the former case, we simply want a warning.  */
4854       if (require_constant && pedantic
4855           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4856         {
4857           inside_init
4858             = valid_compound_expr_initializer (inside_init,
4859                                                TREE_TYPE (inside_init));
4860           if (inside_init == error_mark_node)
4861             error_init ("initializer element is not constant");
4862           else
4863             pedwarn_init ("initializer element is not constant");
4864           if (flag_pedantic_errors)
4865             inside_init = error_mark_node;
4866         }
4867       else if (require_constant
4868                && !initializer_constant_valid_p (inside_init,
4869                                                  TREE_TYPE (inside_init)))
4870         {
4871           error_init ("initializer element is not constant");
4872           inside_init = error_mark_node;
4873         }
4874
4875       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4876       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4877         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4878                                               NULL_TREE, 0);
4879       return inside_init;
4880     }
4881
4882   /* Handle scalar types, including conversions.  */
4883
4884   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4885       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4886       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4887     {
4888       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4889           && (TREE_CODE (init) == STRING_CST
4890               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4891         init = array_to_pointer_conversion (init);
4892       inside_init
4893         = convert_for_assignment (type, init, ic_init,
4894                                   NULL_TREE, NULL_TREE, 0);
4895
4896       /* Check to see if we have already given an error message.  */
4897       if (inside_init == error_mark_node)
4898         ;
4899       else if (require_constant && !TREE_CONSTANT (inside_init))
4900         {
4901           error_init ("initializer element is not constant");
4902           inside_init = error_mark_node;
4903         }
4904       else if (require_constant
4905                && !initializer_constant_valid_p (inside_init,
4906                                                  TREE_TYPE (inside_init)))
4907         {
4908           error_init ("initializer element is not computable at load time");
4909           inside_init = error_mark_node;
4910         }
4911
4912       return inside_init;
4913     }
4914
4915   /* Come here only for records and arrays.  */
4916
4917   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4918     {
4919       error_init ("variable-sized object may not be initialized");
4920       return error_mark_node;
4921     }
4922
4923   error_init ("invalid initializer");
4924   return error_mark_node;
4925 }
4926 \f
4927 /* Handle initializers that use braces.  */
4928
4929 /* Type of object we are accumulating a constructor for.
4930    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4931 static tree constructor_type;
4932
4933 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4934    left to fill.  */
4935 static tree constructor_fields;
4936
4937 /* For an ARRAY_TYPE, this is the specified index
4938    at which to store the next element we get.  */
4939 static tree constructor_index;
4940
4941 /* For an ARRAY_TYPE, this is the maximum index.  */
4942 static tree constructor_max_index;
4943
4944 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4945 static tree constructor_unfilled_fields;
4946
4947 /* For an ARRAY_TYPE, this is the index of the first element
4948    not yet written out.  */
4949 static tree constructor_unfilled_index;
4950
4951 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4952    This is so we can generate gaps between fields, when appropriate.  */
4953 static tree constructor_bit_index;
4954
4955 /* If we are saving up the elements rather than allocating them,
4956    this is the list of elements so far (in reverse order,
4957    most recent first).  */
4958 static VEC(constructor_elt,gc) *constructor_elements;
4959
4960 /* 1 if constructor should be incrementally stored into a constructor chain,
4961    0 if all the elements should be kept in AVL tree.  */
4962 static int constructor_incremental;
4963
4964 /* 1 if so far this constructor's elements are all compile-time constants.  */
4965 static int constructor_constant;
4966
4967 /* 1 if so far this constructor's elements are all valid address constants.  */
4968 static int constructor_simple;
4969
4970 /* 1 if this constructor is erroneous so far.  */
4971 static int constructor_erroneous;
4972
4973 /* Structure for managing pending initializer elements, organized as an
4974    AVL tree.  */
4975
4976 struct init_node
4977 {
4978   struct init_node *left, *right;
4979   struct init_node *parent;
4980   int balance;
4981   tree purpose;
4982   tree value;
4983 };
4984
4985 /* Tree of pending elements at this constructor level.
4986    These are elements encountered out of order
4987    which belong at places we haven't reached yet in actually
4988    writing the output.
4989    Will never hold tree nodes across GC runs.  */
4990 static struct init_node *constructor_pending_elts;
4991
4992 /* The SPELLING_DEPTH of this constructor.  */
4993 static int constructor_depth;
4994
4995 /* DECL node for which an initializer is being read.
4996    0 means we are reading a constructor expression
4997    such as (struct foo) {...}.  */
4998 static tree constructor_decl;
4999
5000 /* Nonzero if this is an initializer for a top-level decl.  */
5001 static int constructor_top_level;
5002
5003 /* Nonzero if there were any member designators in this initializer.  */
5004 static int constructor_designated;
5005
5006 /* Nesting depth of designator list.  */
5007 static int designator_depth;
5008
5009 /* Nonzero if there were diagnosed errors in this designator list.  */
5010 static int designator_erroneous;
5011
5012 \f
5013 /* This stack has a level for each implicit or explicit level of
5014    structuring in the initializer, including the outermost one.  It
5015    saves the values of most of the variables above.  */
5016
5017 struct constructor_range_stack;
5018
5019 struct constructor_stack
5020 {
5021   struct constructor_stack *next;
5022   tree type;
5023   tree fields;
5024   tree index;
5025   tree max_index;
5026   tree unfilled_index;
5027   tree unfilled_fields;
5028   tree bit_index;
5029   VEC(constructor_elt,gc) *elements;
5030   struct init_node *pending_elts;
5031   int offset;
5032   int depth;
5033   /* If value nonzero, this value should replace the entire
5034      constructor at this level.  */
5035   struct c_expr replacement_value;
5036   struct constructor_range_stack *range_stack;
5037   char constant;
5038   char simple;
5039   char implicit;
5040   char erroneous;
5041   char outer;
5042   char incremental;
5043   char designated;
5044 };
5045
5046 static struct constructor_stack *constructor_stack;
5047
5048 /* This stack represents designators from some range designator up to
5049    the last designator in the list.  */
5050
5051 struct constructor_range_stack
5052 {
5053   struct constructor_range_stack *next, *prev;
5054   struct constructor_stack *stack;
5055   tree range_start;
5056   tree index;
5057   tree range_end;
5058   tree fields;
5059 };
5060
5061 static struct constructor_range_stack *constructor_range_stack;
5062
5063 /* This stack records separate initializers that are nested.
5064    Nested initializers can't happen in ANSI C, but GNU C allows them
5065    in cases like { ... (struct foo) { ... } ... }.  */
5066
5067 struct initializer_stack
5068 {
5069   struct initializer_stack *next;
5070   tree decl;
5071   struct constructor_stack *constructor_stack;
5072   struct constructor_range_stack *constructor_range_stack;
5073   VEC(constructor_elt,gc) *elements;
5074   struct spelling *spelling;
5075   struct spelling *spelling_base;
5076   int spelling_size;
5077   char top_level;
5078   char require_constant_value;
5079   char require_constant_elements;
5080 };
5081
5082 static struct initializer_stack *initializer_stack;
5083 \f
5084 /* Prepare to parse and output the initializer for variable DECL.  */
5085
5086 void
5087 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5088 {
5089   const char *locus;
5090   struct initializer_stack *p = XNEW (struct initializer_stack);
5091
5092   p->decl = constructor_decl;
5093   p->require_constant_value = require_constant_value;
5094   p->require_constant_elements = require_constant_elements;
5095   p->constructor_stack = constructor_stack;
5096   p->constructor_range_stack = constructor_range_stack;
5097   p->elements = constructor_elements;
5098   p->spelling = spelling;
5099   p->spelling_base = spelling_base;
5100   p->spelling_size = spelling_size;
5101   p->top_level = constructor_top_level;
5102   p->next = initializer_stack;
5103   initializer_stack = p;
5104
5105   constructor_decl = decl;
5106   constructor_designated = 0;
5107   constructor_top_level = top_level;
5108
5109   if (decl != 0 && decl != error_mark_node)
5110     {
5111       require_constant_value = TREE_STATIC (decl);
5112       require_constant_elements
5113         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5114            /* For a scalar, you can always use any value to initialize,
5115               even within braces.  */
5116            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5117                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5118                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5119                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5120       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5121     }
5122   else
5123     {
5124       require_constant_value = 0;
5125       require_constant_elements = 0;
5126       locus = "(anonymous)";
5127     }
5128
5129   constructor_stack = 0;
5130   constructor_range_stack = 0;
5131
5132   missing_braces_mentioned = 0;
5133
5134   spelling_base = 0;
5135   spelling_size = 0;
5136   RESTORE_SPELLING_DEPTH (0);
5137
5138   if (locus)
5139     push_string (locus);
5140 }
5141
5142 void
5143 finish_init (void)
5144 {
5145   struct initializer_stack *p = initializer_stack;
5146
5147   /* Free the whole constructor stack of this initializer.  */
5148   while (constructor_stack)
5149     {
5150       struct constructor_stack *q = constructor_stack;
5151       constructor_stack = q->next;
5152       free (q);
5153     }
5154
5155   gcc_assert (!constructor_range_stack);
5156
5157   /* Pop back to the data of the outer initializer (if any).  */
5158   free (spelling_base);
5159
5160   constructor_decl = p->decl;
5161   require_constant_value = p->require_constant_value;
5162   require_constant_elements = p->require_constant_elements;
5163   constructor_stack = p->constructor_stack;
5164   constructor_range_stack = p->constructor_range_stack;
5165   constructor_elements = p->elements;
5166   spelling = p->spelling;
5167   spelling_base = p->spelling_base;
5168   spelling_size = p->spelling_size;
5169   constructor_top_level = p->top_level;
5170   initializer_stack = p->next;
5171   free (p);
5172 }
5173 \f
5174 /* Call here when we see the initializer is surrounded by braces.
5175    This is instead of a call to push_init_level;
5176    it is matched by a call to pop_init_level.
5177
5178    TYPE is the type to initialize, for a constructor expression.
5179    For an initializer for a decl, TYPE is zero.  */
5180
5181 void
5182 really_start_incremental_init (tree type)
5183 {
5184   struct constructor_stack *p = XNEW (struct constructor_stack);
5185
5186   if (type == 0)
5187     type = TREE_TYPE (constructor_decl);
5188
5189   if (targetm.vector_opaque_p (type))
5190     error ("opaque vector types cannot be initialized");
5191
5192   p->type = constructor_type;
5193   p->fields = constructor_fields;
5194   p->index = constructor_index;
5195   p->max_index = constructor_max_index;
5196   p->unfilled_index = constructor_unfilled_index;
5197   p->unfilled_fields = constructor_unfilled_fields;
5198   p->bit_index = constructor_bit_index;
5199   p->elements = constructor_elements;
5200   p->constant = constructor_constant;
5201   p->simple = constructor_simple;
5202   p->erroneous = constructor_erroneous;
5203   p->pending_elts = constructor_pending_elts;
5204   p->depth = constructor_depth;
5205   p->replacement_value.value = 0;
5206   p->replacement_value.original_code = ERROR_MARK;
5207   p->implicit = 0;
5208   p->range_stack = 0;
5209   p->outer = 0;
5210   p->incremental = constructor_incremental;
5211   p->designated = constructor_designated;
5212   p->next = 0;
5213   constructor_stack = p;
5214
5215   constructor_constant = 1;
5216   constructor_simple = 1;
5217   constructor_depth = SPELLING_DEPTH ();
5218   constructor_elements = 0;
5219   constructor_pending_elts = 0;
5220   constructor_type = type;
5221   constructor_incremental = 1;
5222   constructor_designated = 0;
5223   designator_depth = 0;
5224   designator_erroneous = 0;
5225
5226   if (TREE_CODE (constructor_type) == RECORD_TYPE
5227       || TREE_CODE (constructor_type) == UNION_TYPE)
5228     {
5229       constructor_fields = TYPE_FIELDS (constructor_type);
5230       /* Skip any nameless bit fields at the beginning.  */
5231       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5232              && DECL_NAME (constructor_fields) == 0)
5233         constructor_fields = TREE_CHAIN (constructor_fields);
5234
5235       constructor_unfilled_fields = constructor_fields;
5236       constructor_bit_index = bitsize_zero_node;
5237     }
5238   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5239     {
5240       if (TYPE_DOMAIN (constructor_type))
5241         {
5242           constructor_max_index
5243             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5244
5245           /* Detect non-empty initializations of zero-length arrays.  */
5246           if (constructor_max_index == NULL_TREE
5247               && TYPE_SIZE (constructor_type))
5248             constructor_max_index = build_int_cst (NULL_TREE, -1);
5249
5250           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5251              to initialize VLAs will cause a proper error; avoid tree
5252              checking errors as well by setting a safe value.  */
5253           if (constructor_max_index
5254               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5255             constructor_max_index = build_int_cst (NULL_TREE, -1);
5256
5257           constructor_index
5258             = convert (bitsizetype,
5259                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5260         }
5261       else
5262         {
5263           constructor_index = bitsize_zero_node;
5264           constructor_max_index = NULL_TREE;
5265         }
5266
5267       constructor_unfilled_index = constructor_index;
5268     }
5269   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5270     {
5271       /* Vectors are like simple fixed-size arrays.  */
5272       constructor_max_index =
5273         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5274       constructor_index = bitsize_zero_node;
5275       constructor_unfilled_index = constructor_index;
5276     }
5277   else
5278     {
5279       /* Handle the case of int x = {5}; */
5280       constructor_fields = constructor_type;
5281       constructor_unfilled_fields = constructor_type;
5282     }
5283 }
5284 \f
5285 /* Push down into a subobject, for initialization.
5286    If this is for an explicit set of braces, IMPLICIT is 0.
5287    If it is because the next element belongs at a lower level,
5288    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5289
5290 void
5291 push_init_level (int implicit)
5292 {
5293   struct constructor_stack *p;
5294   tree value = NULL_TREE;
5295
5296   /* If we've exhausted any levels that didn't have braces,
5297      pop them now.  If implicit == 1, this will have been done in
5298      process_init_element; do not repeat it here because in the case
5299      of excess initializers for an empty aggregate this leads to an
5300      infinite cycle of popping a level and immediately recreating
5301      it.  */
5302   if (implicit != 1)
5303     {
5304       while (constructor_stack->implicit)
5305         {
5306           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5307                || TREE_CODE (constructor_type) == UNION_TYPE)
5308               && constructor_fields == 0)
5309             process_init_element (pop_init_level (1));
5310           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5311                    && constructor_max_index
5312                    && tree_int_cst_lt (constructor_max_index,
5313                                        constructor_index))
5314             process_init_element (pop_init_level (1));
5315           else
5316             break;
5317         }
5318     }
5319
5320   /* Unless this is an explicit brace, we need to preserve previous
5321      content if any.  */
5322   if (implicit)
5323     {
5324       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5325            || TREE_CODE (constructor_type) == UNION_TYPE)
5326           && constructor_fields)
5327         value = find_init_member (constructor_fields);
5328       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5329         value = find_init_member (constructor_index);
5330     }
5331
5332   p = XNEW (struct constructor_stack);
5333   p->type = constructor_type;
5334   p->fields = constructor_fields;
5335   p->index = constructor_index;
5336   p->max_index = constructor_max_index;
5337   p->unfilled_index = constructor_unfilled_index;
5338   p->unfilled_fields = constructor_unfilled_fields;
5339   p->bit_index = constructor_bit_index;
5340   p->elements = constructor_elements;
5341   p->constant = constructor_constant;
5342   p->simple = constructor_simple;
5343   p->erroneous = constructor_erroneous;
5344   p->pending_elts = constructor_pending_elts;
5345   p->depth = constructor_depth;
5346   p->replacement_value.value = 0;
5347   p->replacement_value.original_code = ERROR_MARK;
5348   p->implicit = implicit;
5349   p->outer = 0;
5350   p->incremental = constructor_incremental;
5351   p->designated = constructor_designated;
5352   p->next = constructor_stack;
5353   p->range_stack = 0;
5354   constructor_stack = p;
5355
5356   constructor_constant = 1;
5357   constructor_simple = 1;
5358   constructor_depth = SPELLING_DEPTH ();
5359   constructor_elements = 0;
5360   constructor_incremental = 1;
5361   constructor_designated = 0;
5362   constructor_pending_elts = 0;
5363   if (!implicit)
5364     {
5365       p->range_stack = constructor_range_stack;
5366       constructor_range_stack = 0;
5367       designator_depth = 0;
5368       designator_erroneous = 0;
5369     }
5370
5371   /* Don't die if an entire brace-pair level is superfluous
5372      in the containing level.  */
5373   if (constructor_type == 0)
5374     ;
5375   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5376            || TREE_CODE (constructor_type) == UNION_TYPE)
5377     {
5378       /* Don't die if there are extra init elts at the end.  */
5379       if (constructor_fields == 0)
5380         constructor_type = 0;
5381       else
5382         {
5383           constructor_type = TREE_TYPE (constructor_fields);
5384           push_member_name (constructor_fields);
5385           constructor_depth++;
5386         }
5387     }
5388   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5389     {
5390       constructor_type = TREE_TYPE (constructor_type);
5391       push_array_bounds (tree_low_cst (constructor_index, 1));
5392       constructor_depth++;
5393     }
5394
5395   if (constructor_type == 0)
5396     {
5397       error_init ("extra brace group at end of initializer");
5398       constructor_fields = 0;
5399       constructor_unfilled_fields = 0;
5400       return;
5401     }
5402
5403   if (value && TREE_CODE (value) == CONSTRUCTOR)
5404     {
5405       constructor_constant = TREE_CONSTANT (value);
5406       constructor_simple = TREE_STATIC (value);
5407       constructor_elements = CONSTRUCTOR_ELTS (value);
5408       if (!VEC_empty (constructor_elt, constructor_elements)
5409           && (TREE_CODE (constructor_type) == RECORD_TYPE
5410               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5411         set_nonincremental_init ();
5412     }
5413
5414   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5415     {
5416       missing_braces_mentioned = 1;
5417       warning_init ("missing braces around initializer");
5418     }
5419
5420   if (TREE_CODE (constructor_type) == RECORD_TYPE
5421            || TREE_CODE (constructor_type) == UNION_TYPE)
5422     {
5423       constructor_fields = TYPE_FIELDS (constructor_type);
5424       /* Skip any nameless bit fields at the beginning.  */
5425       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5426              && DECL_NAME (constructor_fields) == 0)
5427         constructor_fields = TREE_CHAIN (constructor_fields);
5428
5429       constructor_unfilled_fields = constructor_fields;
5430       constructor_bit_index = bitsize_zero_node;
5431     }
5432   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5433     {
5434       /* Vectors are like simple fixed-size arrays.  */
5435       constructor_max_index =
5436         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5437       constructor_index = convert (bitsizetype, integer_zero_node);
5438       constructor_unfilled_index = constructor_index;
5439     }
5440   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5441     {
5442       if (TYPE_DOMAIN (constructor_type))
5443         {
5444           constructor_max_index
5445             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5446
5447           /* Detect non-empty initializations of zero-length arrays.  */
5448           if (constructor_max_index == NULL_TREE
5449               && TYPE_SIZE (constructor_type))
5450             constructor_max_index = build_int_cst (NULL_TREE, -1);
5451
5452           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5453              to initialize VLAs will cause a proper error; avoid tree
5454              checking errors as well by setting a safe value.  */
5455           if (constructor_max_index
5456               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5457             constructor_max_index = build_int_cst (NULL_TREE, -1);
5458
5459           constructor_index
5460             = convert (bitsizetype,
5461                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5462         }
5463       else
5464         constructor_index = bitsize_zero_node;
5465
5466       constructor_unfilled_index = constructor_index;
5467       if (value && TREE_CODE (value) == STRING_CST)
5468         {
5469           /* We need to split the char/wchar array into individual
5470              characters, so that we don't have to special case it
5471              everywhere.  */
5472           set_nonincremental_init_from_string (value);
5473         }
5474     }
5475   else
5476     {
5477       if (constructor_type != error_mark_node)
5478         warning_init ("braces around scalar initializer");
5479       constructor_fields = constructor_type;
5480       constructor_unfilled_fields = constructor_type;
5481     }
5482 }
5483
5484 /* At the end of an implicit or explicit brace level,
5485    finish up that level of constructor.  If a single expression
5486    with redundant braces initialized that level, return the
5487    c_expr structure for that expression.  Otherwise, the original_code
5488    element is set to ERROR_MARK.
5489    If we were outputting the elements as they are read, return 0 as the value
5490    from inner levels (process_init_element ignores that),
5491    but return error_mark_node as the value from the outermost level
5492    (that's what we want to put in DECL_INITIAL).
5493    Otherwise, return a CONSTRUCTOR expression as the value.  */
5494
5495 struct c_expr
5496 pop_init_level (int implicit)
5497 {
5498   struct constructor_stack *p;
5499   struct c_expr ret;
5500   ret.value = 0;
5501   ret.original_code = ERROR_MARK;
5502
5503   if (implicit == 0)
5504     {
5505       /* When we come to an explicit close brace,
5506          pop any inner levels that didn't have explicit braces.  */
5507       while (constructor_stack->implicit)
5508         process_init_element (pop_init_level (1));
5509
5510       gcc_assert (!constructor_range_stack);
5511     }
5512
5513   /* Now output all pending elements.  */
5514   constructor_incremental = 1;
5515   output_pending_init_elements (1);
5516
5517   p = constructor_stack;
5518
5519   /* Error for initializing a flexible array member, or a zero-length
5520      array member in an inappropriate context.  */
5521   if (constructor_type && constructor_fields
5522       && TREE_CODE (constructor_type) == ARRAY_TYPE
5523       && TYPE_DOMAIN (constructor_type)
5524       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5525     {
5526       /* Silently discard empty initializations.  The parser will
5527          already have pedwarned for empty brackets.  */
5528       if (integer_zerop (constructor_unfilled_index))
5529         constructor_type = NULL_TREE;
5530       else
5531         {
5532           gcc_assert (!TYPE_SIZE (constructor_type));
5533
5534           if (constructor_depth > 2)
5535             error_init ("initialization of flexible array member in a nested context");
5536           else if (pedantic)
5537             pedwarn_init ("initialization of a flexible array member");
5538
5539           /* We have already issued an error message for the existence
5540              of a flexible array member not at the end of the structure.
5541              Discard the initializer so that we do not die later.  */
5542           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5543             constructor_type = NULL_TREE;
5544         }
5545     }
5546
5547   /* Warn when some struct elements are implicitly initialized to zero.  */
5548   if (warn_missing_field_initializers
5549       && constructor_type
5550       && TREE_CODE (constructor_type) == RECORD_TYPE
5551       && constructor_unfilled_fields)
5552     {
5553         /* Do not warn for flexible array members or zero-length arrays.  */
5554         while (constructor_unfilled_fields
5555                && (!DECL_SIZE (constructor_unfilled_fields)
5556                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5557           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5558
5559         /* Do not warn if this level of the initializer uses member
5560            designators; it is likely to be deliberate.  */
5561         if (constructor_unfilled_fields && !constructor_designated)
5562           {
5563             push_member_name (constructor_unfilled_fields);
5564             warning_init ("missing initializer");
5565             RESTORE_SPELLING_DEPTH (constructor_depth);
5566           }
5567     }
5568
5569   /* Pad out the end of the structure.  */
5570   if (p->replacement_value.value)
5571     /* If this closes a superfluous brace pair,
5572        just pass out the element between them.  */
5573     ret = p->replacement_value;
5574   else if (constructor_type == 0)
5575     ;
5576   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5577            && TREE_CODE (constructor_type) != UNION_TYPE
5578            && TREE_CODE (constructor_type) != ARRAY_TYPE
5579            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5580     {
5581       /* A nonincremental scalar initializer--just return
5582          the element, after verifying there is just one.  */
5583       if (VEC_empty (constructor_elt,constructor_elements))
5584         {
5585           if (!constructor_erroneous)
5586             error_init ("empty scalar initializer");
5587           ret.value = error_mark_node;
5588         }
5589       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5590         {
5591           error_init ("extra elements in scalar initializer");
5592           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5593         }
5594       else
5595         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5596     }
5597   else
5598     {
5599       if (constructor_erroneous)
5600         ret.value = error_mark_node;
5601       else
5602         {
5603           ret.value = build_constructor (constructor_type,
5604                                          constructor_elements);
5605           if (constructor_constant)
5606             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5607           if (constructor_constant && constructor_simple)
5608             TREE_STATIC (ret.value) = 1;
5609         }
5610     }
5611
5612   constructor_type = p->type;
5613   constructor_fields = p->fields;
5614   constructor_index = p->index;
5615   constructor_max_index = p->max_index;
5616   constructor_unfilled_index = p->unfilled_index;
5617   constructor_unfilled_fields = p->unfilled_fields;
5618   constructor_bit_index = p->bit_index;
5619   constructor_elements = p->elements;
5620   constructor_constant = p->constant;
5621   constructor_simple = p->simple;
5622   constructor_erroneous = p->erroneous;
5623   constructor_incremental = p->incremental;
5624   constructor_designated = p->designated;
5625   constructor_pending_elts = p->pending_elts;
5626   constructor_depth = p->depth;
5627   if (!p->implicit)
5628     constructor_range_stack = p->range_stack;
5629   RESTORE_SPELLING_DEPTH (constructor_depth);
5630
5631   constructor_stack = p->next;
5632   free (p);
5633
5634   if (ret.value == 0 && constructor_stack == 0)
5635     ret.value = error_mark_node;
5636   return ret;
5637 }
5638
5639 /* Common handling for both array range and field name designators.
5640    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5641
5642 static int
5643 set_designator (int array)
5644 {
5645   tree subtype;
5646   enum tree_code subcode;
5647
5648   /* Don't die if an entire brace-pair level is superfluous
5649      in the containing level.  */
5650   if (constructor_type == 0)
5651     return 1;
5652
5653   /* If there were errors in this designator list already, bail out
5654      silently.  */
5655   if (designator_erroneous)
5656     return 1;
5657
5658   if (!designator_depth)
5659     {
5660       gcc_assert (!constructor_range_stack);
5661
5662       /* Designator list starts at the level of closest explicit
5663          braces.  */
5664       while (constructor_stack->implicit)
5665         process_init_element (pop_init_level (1));
5666       constructor_designated = 1;
5667       return 0;
5668     }
5669
5670   switch (TREE_CODE (constructor_type))
5671     {
5672     case  RECORD_TYPE:
5673     case  UNION_TYPE:
5674       subtype = TREE_TYPE (constructor_fields);
5675       if (subtype != error_mark_node)
5676         subtype = TYPE_MAIN_VARIANT (subtype);
5677       break;
5678     case ARRAY_TYPE:
5679       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5680       break;
5681     default:
5682       gcc_unreachable ();
5683     }
5684
5685   subcode = TREE_CODE (subtype);
5686   if (array && subcode != ARRAY_TYPE)
5687     {
5688       error_init ("array index in non-array initializer");
5689       return 1;
5690     }
5691   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5692     {
5693       error_init ("field name not in record or union initializer");
5694       return 1;
5695     }
5696
5697   constructor_designated = 1;
5698   push_init_level (2);
5699   return 0;
5700 }
5701
5702 /* If there are range designators in designator list, push a new designator
5703    to constructor_range_stack.  RANGE_END is end of such stack range or
5704    NULL_TREE if there is no range designator at this level.  */
5705
5706 static void
5707 push_range_stack (tree range_end)
5708 {
5709   struct constructor_range_stack *p;
5710
5711   p = GGC_NEW (struct constructor_range_stack);
5712   p->prev = constructor_range_stack;
5713   p->next = 0;
5714   p->fields = constructor_fields;
5715   p->range_start = constructor_index;
5716   p->index = constructor_index;
5717   p->stack = constructor_stack;
5718   p->range_end = range_end;
5719   if (constructor_range_stack)
5720     constructor_range_stack->next = p;
5721   constructor_range_stack = p;
5722 }
5723
5724 /* Within an array initializer, specify the next index to be initialized.
5725    FIRST is that index.  If LAST is nonzero, then initialize a range
5726    of indices, running from FIRST through LAST.  */
5727
5728 void
5729 set_init_index (tree first, tree last)
5730 {
5731   if (set_designator (1))
5732     return;
5733
5734   designator_erroneous = 1;
5735
5736   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5737       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5738     {
5739       error_init ("array index in initializer not of integer type");
5740       return;
5741     }
5742
5743   if (TREE_CODE (first) != INTEGER_CST)
5744     error_init ("nonconstant array index in initializer");
5745   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5746     error_init ("nonconstant array index in initializer");
5747   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5748     error_init ("array index in non-array initializer");
5749   else if (tree_int_cst_sgn (first) == -1)
5750     error_init ("array index in initializer exceeds array bounds");
5751   else if (constructor_max_index
5752            && tree_int_cst_lt (constructor_max_index, first))
5753     error_init ("array index in initializer exceeds array bounds");
5754   else
5755     {
5756       constructor_index = convert (bitsizetype, first);
5757
5758       if (last)
5759         {
5760           if (tree_int_cst_equal (first, last))
5761             last = 0;
5762           else if (tree_int_cst_lt (last, first))
5763             {
5764               error_init ("empty index range in initializer");
5765               last = 0;
5766             }
5767           else
5768             {
5769               last = convert (bitsizetype, last);
5770               if (constructor_max_index != 0
5771                   && tree_int_cst_lt (constructor_max_index, last))
5772                 {
5773                   error_init ("array index range in initializer exceeds array bounds");
5774                   last = 0;
5775                 }
5776             }
5777         }
5778
5779       designator_depth++;
5780       designator_erroneous = 0;
5781       if (constructor_range_stack || last)
5782         push_range_stack (last);
5783     }
5784 }
5785
5786 /* Within a struct initializer, specify the next field to be initialized.  */
5787
5788 void
5789 set_init_label (tree fieldname)
5790 {
5791   tree tail;
5792
5793   if (set_designator (0))
5794     return;
5795
5796   designator_erroneous = 1;
5797
5798   if (TREE_CODE (constructor_type) != RECORD_TYPE
5799       && TREE_CODE (constructor_type) != UNION_TYPE)
5800     {
5801       error_init ("field name not in record or union initializer");
5802       return;
5803     }
5804
5805   for (tail = TYPE_FIELDS (constructor_type); tail;
5806        tail = TREE_CHAIN (tail))
5807     {
5808       if (DECL_NAME (tail) == fieldname)
5809         break;
5810     }
5811
5812   if (tail == 0)
5813     error ("unknown field %qE specified in initializer", fieldname);
5814   else
5815     {
5816       constructor_fields = tail;
5817       designator_depth++;
5818       designator_erroneous = 0;
5819       if (constructor_range_stack)
5820         push_range_stack (NULL_TREE);
5821     }
5822 }
5823 \f
5824 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5825    identifies the initializer, either array index or field in a structure.
5826    VALUE is the value of that index or field.  */
5827
5828 static void
5829 add_pending_init (tree purpose, tree value)
5830 {
5831   struct init_node *p, **q, *r;
5832
5833   q = &constructor_pending_elts;
5834   p = 0;
5835
5836   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5837     {
5838       while (*q != 0)
5839         {
5840           p = *q;
5841           if (tree_int_cst_lt (purpose, p->purpose))
5842             q = &p->left;
5843           else if (tree_int_cst_lt (p->purpose, purpose))
5844             q = &p->right;
5845           else
5846             {
5847               if (TREE_SIDE_EFFECTS (p->value))
5848                 warning_init ("initialized field with side-effects overwritten");
5849               else if (warn_override_init)
5850                 warning_init ("initialized field overwritten");
5851               p->value = value;
5852               return;
5853             }
5854         }
5855     }
5856   else
5857     {
5858       tree bitpos;
5859
5860       bitpos = bit_position (purpose);
5861       while (*q != NULL)
5862         {
5863           p = *q;
5864           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5865             q = &p->left;
5866           else if (p->purpose != purpose)
5867             q = &p->right;
5868           else
5869             {
5870               if (TREE_SIDE_EFFECTS (p->value))
5871                 warning_init ("initialized field with side-effects overwritten");
5872               else if (warn_override_init)
5873                 warning_init ("initialized field overwritten");
5874               p->value = value;
5875               return;
5876             }
5877         }
5878     }
5879
5880   r = GGC_NEW (struct init_node);
5881   r->purpose = purpose;
5882   r->value = value;
5883
5884   *q = r;
5885   r->parent = p;
5886   r->left = 0;
5887   r->right = 0;
5888   r->balance = 0;
5889
5890   while (p)
5891     {
5892       struct init_node *s;
5893
5894       if (r == p->left)
5895         {
5896           if (p->balance == 0)
5897             p->balance = -1;
5898           else if (p->balance < 0)
5899             {
5900               if (r->balance < 0)
5901                 {
5902                   /* L rotation.  */
5903                   p->left = r->right;
5904                   if (p->left)
5905                     p->left->parent = p;
5906                   r->right = p;
5907
5908                   p->balance = 0;
5909                   r->balance = 0;
5910
5911                   s = p->parent;
5912                   p->parent = r;
5913                   r->parent = s;
5914                   if (s)
5915                     {
5916                       if (s->left == p)
5917                         s->left = r;
5918                       else
5919                         s->right = r;
5920                     }
5921                   else
5922                     constructor_pending_elts = r;
5923                 }
5924               else
5925                 {
5926                   /* LR rotation.  */
5927                   struct init_node *t = r->right;
5928
5929                   r->right = t->left;
5930                   if (r->right)
5931                     r->right->parent = r;
5932                   t->left = r;
5933
5934                   p->left = t->right;
5935                   if (p->left)
5936                     p->left->parent = p;
5937                   t->right = p;
5938
5939                   p->balance = t->balance < 0;
5940                   r->balance = -(t->balance > 0);
5941                   t->balance = 0;
5942
5943                   s = p->parent;
5944                   p->parent = t;
5945                   r->parent = t;
5946                   t->parent = s;
5947                   if (s)
5948                     {
5949                       if (s->left == p)
5950                         s->left = t;
5951                       else
5952                         s->right = t;
5953                     }
5954                   else
5955                     constructor_pending_elts = t;
5956                 }
5957               break;
5958             }
5959           else
5960             {
5961               /* p->balance == +1; growth of left side balances the node.  */
5962               p->balance = 0;
5963               break;
5964             }
5965         }
5966       else /* r == p->right */
5967         {
5968           if (p->balance == 0)
5969             /* Growth propagation from right side.  */
5970             p->balance++;
5971           else if (p->balance > 0)
5972             {
5973               if (r->balance > 0)
5974                 {
5975                   /* R rotation.  */
5976                   p->right = r->left;
5977                   if (p->right)
5978                     p->right->parent = p;
5979                   r->left = p;
5980
5981                   p->balance = 0;
5982                   r->balance = 0;
5983
5984                   s = p->parent;
5985                   p->parent = r;
5986                   r->parent = s;
5987                   if (s)
5988                     {
5989                       if (s->left == p)
5990                         s->left = r;
5991                       else
5992                         s->right = r;
5993                     }
5994                   else
5995                     constructor_pending_elts = r;
5996                 }
5997               else /* r->balance == -1 */
5998                 {
5999                   /* RL rotation */
6000                   struct init_node *t = r->left;
6001
6002                   r->left = t->right;
6003                   if (r->left)
6004                     r->left->parent = r;
6005                   t->right = r;
6006
6007                   p->right = t->left;
6008                   if (p->right)
6009                     p->right->parent = p;
6010                   t->left = p;
6011
6012                   r->balance = (t->balance < 0);
6013                   p->balance = -(t->balance > 0);
6014                   t->balance = 0;
6015
6016                   s = p->parent;
6017                   p->parent = t;
6018                   r->parent = t;
6019                   t->parent = s;
6020                   if (s)
6021                     {
6022                       if (s->left == p)
6023                         s->left = t;
6024                       else
6025                         s->right = t;
6026                     }
6027                   else
6028                     constructor_pending_elts = t;
6029                 }
6030               break;
6031             }
6032           else
6033             {
6034               /* p->balance == -1; growth of right side balances the node.  */
6035               p->balance = 0;
6036               break;
6037             }
6038         }
6039
6040       r = p;
6041       p = p->parent;
6042     }
6043 }
6044
6045 /* Build AVL tree from a sorted chain.  */
6046
6047 static void
6048 set_nonincremental_init (void)
6049 {
6050   unsigned HOST_WIDE_INT ix;
6051   tree index, value;
6052
6053   if (TREE_CODE (constructor_type) != RECORD_TYPE
6054       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6055     return;
6056
6057   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6058     add_pending_init (index, value);
6059   constructor_elements = 0;
6060   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6061     {
6062       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6063       /* Skip any nameless bit fields at the beginning.  */
6064       while (constructor_unfilled_fields != 0
6065              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6066              && DECL_NAME (constructor_unfilled_fields) == 0)
6067         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6068
6069     }
6070   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6071     {
6072       if (TYPE_DOMAIN (constructor_type))
6073         constructor_unfilled_index
6074             = convert (bitsizetype,
6075                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6076       else
6077         constructor_unfilled_index = bitsize_zero_node;
6078     }
6079   constructor_incremental = 0;
6080 }
6081
6082 /* Build AVL tree from a string constant.  */
6083
6084 static void
6085 set_nonincremental_init_from_string (tree str)
6086 {
6087   tree value, purpose, type;
6088   HOST_WIDE_INT val[2];
6089   const char *p, *end;
6090   int byte, wchar_bytes, charwidth, bitpos;
6091
6092   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6093
6094   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6095       == TYPE_PRECISION (char_type_node))
6096     wchar_bytes = 1;
6097   else
6098     {
6099       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6100                   == TYPE_PRECISION (wchar_type_node));
6101       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6102     }
6103   charwidth = TYPE_PRECISION (char_type_node);
6104   type = TREE_TYPE (constructor_type);
6105   p = TREE_STRING_POINTER (str);
6106   end = p + TREE_STRING_LENGTH (str);
6107
6108   for (purpose = bitsize_zero_node;
6109        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6110        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6111     {
6112       if (wchar_bytes == 1)
6113         {
6114           val[1] = (unsigned char) *p++;
6115           val[0] = 0;
6116         }
6117       else
6118         {
6119           val[0] = 0;
6120           val[1] = 0;
6121           for (byte = 0; byte < wchar_bytes; byte++)
6122             {
6123               if (BYTES_BIG_ENDIAN)
6124                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6125               else
6126                 bitpos = byte * charwidth;
6127               val[bitpos < HOST_BITS_PER_WIDE_INT]
6128                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6129                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6130             }
6131         }
6132
6133       if (!TYPE_UNSIGNED (type))
6134         {
6135           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6136           if (bitpos < HOST_BITS_PER_WIDE_INT)
6137             {
6138               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6139                 {
6140                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6141                   val[0] = -1;
6142                 }
6143             }
6144           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6145             {
6146               if (val[1] < 0)
6147                 val[0] = -1;
6148             }
6149           else if (val[0] & (((HOST_WIDE_INT) 1)
6150                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6151             val[0] |= ((HOST_WIDE_INT) -1)
6152                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6153         }
6154
6155       value = build_int_cst_wide (type, val[1], val[0]);
6156       add_pending_init (purpose, value);
6157     }
6158
6159   constructor_incremental = 0;
6160 }
6161
6162 /* Return value of FIELD in pending initializer or zero if the field was
6163    not initialized yet.  */
6164
6165 static tree
6166 find_init_member (tree field)
6167 {
6168   struct init_node *p;
6169
6170   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6171     {
6172       if (constructor_incremental
6173           && tree_int_cst_lt (field, constructor_unfilled_index))
6174         set_nonincremental_init ();
6175
6176       p = constructor_pending_elts;
6177       while (p)
6178         {
6179           if (tree_int_cst_lt (field, p->purpose))
6180             p = p->left;
6181           else if (tree_int_cst_lt (p->purpose, field))
6182             p = p->right;
6183           else
6184             return p->value;
6185         }
6186     }
6187   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6188     {
6189       tree bitpos = bit_position (field);
6190
6191       if (constructor_incremental
6192           && (!constructor_unfilled_fields
6193               || tree_int_cst_lt (bitpos,
6194                                   bit_position (constructor_unfilled_fields))))
6195         set_nonincremental_init ();
6196
6197       p = constructor_pending_elts;
6198       while (p)
6199         {
6200           if (field == p->purpose)
6201             return p->value;
6202           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6203             p = p->left;
6204           else
6205             p = p->right;
6206         }
6207     }
6208   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6209     {
6210       if (!VEC_empty (constructor_elt, constructor_elements)
6211           && (VEC_last (constructor_elt, constructor_elements)->index
6212               == field))
6213         return VEC_last (constructor_elt, constructor_elements)->value;
6214     }
6215   return 0;
6216 }
6217
6218 /* "Output" the next constructor element.
6219    At top level, really output it to assembler code now.
6220    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6221    TYPE is the data type that the containing data type wants here.
6222    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6223    If VALUE is a string constant, STRICT_STRING is true if it is
6224    unparenthesized or we should not warn here for it being parenthesized.
6225    For other types of VALUE, STRICT_STRING is not used.
6226
6227    PENDING if non-nil means output pending elements that belong
6228    right after this element.  (PENDING is normally 1;
6229    it is 0 while outputting pending elements, to avoid recursion.)  */
6230
6231 static void
6232 output_init_element (tree value, bool strict_string, tree type, tree field,
6233                      int pending)
6234 {
6235   constructor_elt *celt;
6236
6237   if (type == error_mark_node || value == error_mark_node)
6238     {
6239       constructor_erroneous = 1;
6240       return;
6241     }
6242   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6243       && (TREE_CODE (value) == STRING_CST
6244           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6245       && !(TREE_CODE (value) == STRING_CST
6246            && TREE_CODE (type) == ARRAY_TYPE
6247            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6248       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6249                      TYPE_MAIN_VARIANT (type)))
6250     value = array_to_pointer_conversion (value);
6251
6252   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6253       && require_constant_value && !flag_isoc99 && pending)
6254     {
6255       /* As an extension, allow initializing objects with static storage
6256          duration with compound literals (which are then treated just as
6257          the brace enclosed list they contain).  */
6258       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6259       value = DECL_INITIAL (decl);
6260     }
6261
6262   if (value == error_mark_node)
6263     constructor_erroneous = 1;
6264   else if (!TREE_CONSTANT (value))
6265     constructor_constant = 0;
6266   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6267            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6268                 || TREE_CODE (constructor_type) == UNION_TYPE)
6269                && DECL_C_BIT_FIELD (field)
6270                && TREE_CODE (value) != INTEGER_CST))
6271     constructor_simple = 0;
6272
6273   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6274     {
6275       if (require_constant_value)
6276         {
6277           error_init ("initializer element is not constant");
6278           value = error_mark_node;
6279         }
6280       else if (require_constant_elements)
6281         pedwarn ("initializer element is not computable at load time");
6282     }
6283
6284   /* If this field is empty (and not at the end of structure),
6285      don't do anything other than checking the initializer.  */
6286   if (field
6287       && (TREE_TYPE (field) == error_mark_node
6288           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6289               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6290               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6291                   || TREE_CHAIN (field)))))
6292     return;
6293
6294   value = digest_init (type, value, strict_string, require_constant_value);
6295   if (value == error_mark_node)
6296     {
6297       constructor_erroneous = 1;
6298       return;
6299     }
6300
6301   /* If this element doesn't come next in sequence,
6302      put it on constructor_pending_elts.  */
6303   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6304       && (!constructor_incremental
6305           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6306     {
6307       if (constructor_incremental
6308           && tree_int_cst_lt (field, constructor_unfilled_index))
6309         set_nonincremental_init ();
6310
6311       add_pending_init (field, value);
6312       return;
6313     }
6314   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6315            && (!constructor_incremental
6316                || field != constructor_unfilled_fields))
6317     {
6318       /* We do this for records but not for unions.  In a union,
6319          no matter which field is specified, it can be initialized
6320          right away since it starts at the beginning of the union.  */
6321       if (constructor_incremental)
6322         {
6323           if (!constructor_unfilled_fields)
6324             set_nonincremental_init ();
6325           else
6326             {
6327               tree bitpos, unfillpos;
6328
6329               bitpos = bit_position (field);
6330               unfillpos = bit_position (constructor_unfilled_fields);
6331
6332               if (tree_int_cst_lt (bitpos, unfillpos))
6333                 set_nonincremental_init ();
6334             }
6335         }
6336
6337       add_pending_init (field, value);
6338       return;
6339     }
6340   else if (TREE_CODE (constructor_type) == UNION_TYPE
6341            && !VEC_empty (constructor_elt, constructor_elements))
6342     {
6343       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6344                                        constructor_elements)->value))
6345         warning_init ("initialized field with side-effects overwritten");
6346       else if (warn_override_init)
6347         warning_init ("initialized field overwritten");
6348
6349       /* We can have just one union field set.  */
6350       constructor_elements = 0;
6351     }
6352
6353   /* Otherwise, output this element either to
6354      constructor_elements or to the assembler file.  */
6355
6356   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6357   celt->index = field;
6358   celt->value = value;
6359
6360   /* Advance the variable that indicates sequential elements output.  */
6361   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6362     constructor_unfilled_index
6363       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6364                     bitsize_one_node);
6365   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6366     {
6367       constructor_unfilled_fields
6368         = TREE_CHAIN (constructor_unfilled_fields);
6369
6370       /* Skip any nameless bit fields.  */
6371       while (constructor_unfilled_fields != 0
6372              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6373              && DECL_NAME (constructor_unfilled_fields) == 0)
6374         constructor_unfilled_fields =
6375           TREE_CHAIN (constructor_unfilled_fields);
6376     }
6377   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6378     constructor_unfilled_fields = 0;
6379
6380   /* Now output any pending elements which have become next.  */
6381   if (pending)
6382     output_pending_init_elements (0);
6383 }
6384
6385 /* Output any pending elements which have become next.
6386    As we output elements, constructor_unfilled_{fields,index}
6387    advances, which may cause other elements to become next;
6388    if so, they too are output.
6389
6390    If ALL is 0, we return when there are
6391    no more pending elements to output now.
6392
6393    If ALL is 1, we output space as necessary so that
6394    we can output all the pending elements.  */
6395
6396 static void
6397 output_pending_init_elements (int all)
6398 {
6399   struct init_node *elt = constructor_pending_elts;
6400   tree next;
6401
6402  retry:
6403
6404   /* Look through the whole pending tree.
6405      If we find an element that should be output now,
6406      output it.  Otherwise, set NEXT to the element
6407      that comes first among those still pending.  */
6408
6409   next = 0;
6410   while (elt)
6411     {
6412       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6413         {
6414           if (tree_int_cst_equal (elt->purpose,
6415                                   constructor_unfilled_index))
6416             output_init_element (elt->value, true,
6417                                  TREE_TYPE (constructor_type),
6418                                  constructor_unfilled_index, 0);
6419           else if (tree_int_cst_lt (constructor_unfilled_index,
6420                                     elt->purpose))
6421             {
6422               /* Advance to the next smaller node.  */
6423               if (elt->left)
6424                 elt = elt->left;
6425               else
6426                 {
6427                   /* We have reached the smallest node bigger than the
6428                      current unfilled index.  Fill the space first.  */
6429                   next = elt->purpose;
6430                   break;
6431                 }
6432             }
6433           else
6434             {
6435               /* Advance to the next bigger node.  */
6436               if (elt->right)
6437                 elt = elt->right;
6438               else
6439                 {
6440                   /* We have reached the biggest node in a subtree.  Find
6441                      the parent of it, which is the next bigger node.  */
6442                   while (elt->parent && elt->parent->right == elt)
6443                     elt = elt->parent;
6444                   elt = elt->parent;
6445                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6446                                               elt->purpose))
6447                     {
6448                       next = elt->purpose;
6449                       break;
6450                     }
6451                 }
6452             }
6453         }
6454       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6455                || TREE_CODE (constructor_type) == UNION_TYPE)
6456         {
6457           tree ctor_unfilled_bitpos, elt_bitpos;
6458
6459           /* If the current record is complete we are done.  */
6460           if (constructor_unfilled_fields == 0)
6461             break;
6462
6463           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6464           elt_bitpos = bit_position (elt->purpose);
6465           /* We can't compare fields here because there might be empty
6466              fields in between.  */
6467           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6468             {
6469               constructor_unfilled_fields = elt->purpose;
6470               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6471                                    elt->purpose, 0);
6472             }
6473           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6474             {
6475               /* Advance to the next smaller node.  */
6476               if (elt->left)
6477                 elt = elt->left;
6478               else
6479                 {
6480                   /* We have reached the smallest node bigger than the
6481                      current unfilled field.  Fill the space first.  */
6482                   next = elt->purpose;
6483                   break;
6484                 }
6485             }
6486           else
6487             {
6488               /* Advance to the next bigger node.  */
6489               if (elt->right)
6490                 elt = elt->right;
6491               else
6492                 {
6493                   /* We have reached the biggest node in a subtree.  Find
6494                      the parent of it, which is the next bigger node.  */
6495                   while (elt->parent && elt->parent->right == elt)
6496                     elt = elt->parent;
6497                   elt = elt->parent;
6498                   if (elt
6499                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6500                                            bit_position (elt->purpose))))
6501                     {
6502                       next = elt->purpose;
6503                       break;
6504                     }
6505                 }
6506             }
6507         }
6508     }
6509
6510   /* Ordinarily return, but not if we want to output all
6511      and there are elements left.  */
6512   if (!(all && next != 0))
6513     return;
6514
6515   /* If it's not incremental, just skip over the gap, so that after
6516      jumping to retry we will output the next successive element.  */
6517   if (TREE_CODE (constructor_type) == RECORD_TYPE
6518       || TREE_CODE (constructor_type) == UNION_TYPE)
6519     constructor_unfilled_fields = next;
6520   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6521     constructor_unfilled_index = next;
6522
6523   /* ELT now points to the node in the pending tree with the next
6524      initializer to output.  */
6525   goto retry;
6526 }
6527 \f
6528 /* Add one non-braced element to the current constructor level.
6529    This adjusts the current position within the constructor's type.
6530    This may also start or terminate implicit levels
6531    to handle a partly-braced initializer.
6532
6533    Once this has found the correct level for the new element,
6534    it calls output_init_element.  */
6535
6536 void
6537 process_init_element (struct c_expr value)
6538 {
6539   tree orig_value = value.value;
6540   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6541   bool strict_string = value.original_code == STRING_CST;
6542
6543   designator_depth = 0;
6544   designator_erroneous = 0;
6545
6546   /* Handle superfluous braces around string cst as in
6547      char x[] = {"foo"}; */
6548   if (string_flag
6549       && constructor_type
6550       && TREE_CODE (constructor_type) == ARRAY_TYPE
6551       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6552       && integer_zerop (constructor_unfilled_index))
6553     {
6554       if (constructor_stack->replacement_value.value)
6555         error_init ("excess elements in char array initializer");
6556       constructor_stack->replacement_value = value;
6557       return;
6558     }
6559
6560   if (constructor_stack->replacement_value.value != 0)
6561     {
6562       error_init ("excess elements in struct initializer");
6563       return;
6564     }
6565
6566   /* Ignore elements of a brace group if it is entirely superfluous
6567      and has already been diagnosed.  */
6568   if (constructor_type == 0)
6569     return;
6570
6571   /* If we've exhausted any levels that didn't have braces,
6572      pop them now.  */
6573   while (constructor_stack->implicit)
6574     {
6575       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6576            || TREE_CODE (constructor_type) == UNION_TYPE)
6577           && constructor_fields == 0)
6578         process_init_element (pop_init_level (1));
6579       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6580                && (constructor_max_index == 0
6581                    || tree_int_cst_lt (constructor_max_index,
6582                                        constructor_index)))
6583         process_init_element (pop_init_level (1));
6584       else
6585         break;
6586     }
6587
6588   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6589   if (constructor_range_stack)
6590     {
6591       /* If value is a compound literal and we'll be just using its
6592          content, don't put it into a SAVE_EXPR.  */
6593       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6594           || !require_constant_value
6595           || flag_isoc99)
6596         value.value = save_expr (value.value);
6597     }
6598
6599   while (1)
6600     {
6601       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6602         {
6603           tree fieldtype;
6604           enum tree_code fieldcode;
6605
6606           if (constructor_fields == 0)
6607             {
6608               pedwarn_init ("excess elements in struct initializer");
6609               break;
6610             }
6611
6612           fieldtype = TREE_TYPE (constructor_fields);
6613           if (fieldtype != error_mark_node)
6614             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6615           fieldcode = TREE_CODE (fieldtype);
6616
6617           /* Error for non-static initialization of a flexible array member.  */
6618           if (fieldcode == ARRAY_TYPE
6619               && !require_constant_value
6620               && TYPE_SIZE (fieldtype) == NULL_TREE
6621               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6622             {
6623               error_init ("non-static initialization of a flexible array member");
6624               break;
6625             }
6626
6627           /* Accept a string constant to initialize a subarray.  */
6628           if (value.value != 0
6629               && fieldcode == ARRAY_TYPE
6630               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6631               && string_flag)
6632             value.value = orig_value;
6633           /* Otherwise, if we have come to a subaggregate,
6634              and we don't have an element of its type, push into it.  */
6635           else if (value.value != 0
6636                    && value.value != error_mark_node
6637                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6638                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6639                        || fieldcode == UNION_TYPE))
6640             {
6641               push_init_level (1);
6642               continue;
6643             }
6644
6645           if (value.value)
6646             {
6647               push_member_name (constructor_fields);
6648               output_init_element (value.value, strict_string,
6649                                    fieldtype, constructor_fields, 1);
6650               RESTORE_SPELLING_DEPTH (constructor_depth);
6651             }
6652           else
6653             /* Do the bookkeeping for an element that was
6654                directly output as a constructor.  */
6655             {
6656               /* For a record, keep track of end position of last field.  */
6657               if (DECL_SIZE (constructor_fields))
6658                 constructor_bit_index
6659                   = size_binop (PLUS_EXPR,
6660                                 bit_position (constructor_fields),
6661                                 DECL_SIZE (constructor_fields));
6662
6663               /* If the current field was the first one not yet written out,
6664                  it isn't now, so update.  */
6665               if (constructor_unfilled_fields == constructor_fields)
6666                 {
6667                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6668                   /* Skip any nameless bit fields.  */
6669                   while (constructor_unfilled_fields != 0
6670                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6671                          && DECL_NAME (constructor_unfilled_fields) == 0)
6672                     constructor_unfilled_fields =
6673                       TREE_CHAIN (constructor_unfilled_fields);
6674                 }
6675             }
6676
6677           constructor_fields = TREE_CHAIN (constructor_fields);
6678           /* Skip any nameless bit fields at the beginning.  */
6679           while (constructor_fields != 0
6680                  && DECL_C_BIT_FIELD (constructor_fields)
6681                  && DECL_NAME (constructor_fields) == 0)
6682             constructor_fields = TREE_CHAIN (constructor_fields);
6683         }
6684       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6685         {
6686           tree fieldtype;
6687           enum tree_code fieldcode;
6688
6689           if (constructor_fields == 0)
6690             {
6691               pedwarn_init ("excess elements in union initializer");
6692               break;
6693             }
6694
6695           fieldtype = TREE_TYPE (constructor_fields);
6696           if (fieldtype != error_mark_node)
6697             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6698           fieldcode = TREE_CODE (fieldtype);
6699
6700           /* Warn that traditional C rejects initialization of unions.
6701              We skip the warning if the value is zero.  This is done
6702              under the assumption that the zero initializer in user
6703              code appears conditioned on e.g. __STDC__ to avoid
6704              "missing initializer" warnings and relies on default
6705              initialization to zero in the traditional C case.
6706              We also skip the warning if the initializer is designated,
6707              again on the assumption that this must be conditional on
6708              __STDC__ anyway (and we've already complained about the
6709              member-designator already).  */
6710           if (!in_system_header && !constructor_designated
6711               && !(value.value && (integer_zerop (value.value)
6712                                    || real_zerop (value.value))))
6713             warning (OPT_Wtraditional, "traditional C rejects initialization "
6714                      "of unions");
6715
6716           /* Accept a string constant to initialize a subarray.  */
6717           if (value.value != 0
6718               && fieldcode == ARRAY_TYPE
6719               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6720               && string_flag)
6721             value.value = orig_value;
6722           /* Otherwise, if we have come to a subaggregate,
6723              and we don't have an element of its type, push into it.  */
6724           else if (value.value != 0
6725                    && value.value != error_mark_node
6726                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6727                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6728                        || fieldcode == UNION_TYPE))
6729             {
6730               push_init_level (1);
6731               continue;
6732             }
6733
6734           if (value.value)
6735             {
6736               push_member_name (constructor_fields);
6737               output_init_element (value.value, strict_string,
6738                                    fieldtype, constructor_fields, 1);
6739               RESTORE_SPELLING_DEPTH (constructor_depth);
6740             }
6741           else
6742             /* Do the bookkeeping for an element that was
6743                directly output as a constructor.  */
6744             {
6745               constructor_bit_index = DECL_SIZE (constructor_fields);
6746               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6747             }
6748
6749           constructor_fields = 0;
6750         }
6751       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6752         {
6753           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6754           enum tree_code eltcode = TREE_CODE (elttype);
6755
6756           /* Accept a string constant to initialize a subarray.  */
6757           if (value.value != 0
6758               && eltcode == ARRAY_TYPE
6759               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6760               && string_flag)
6761             value.value = orig_value;
6762           /* Otherwise, if we have come to a subaggregate,
6763              and we don't have an element of its type, push into it.  */
6764           else if (value.value != 0
6765                    && value.value != error_mark_node
6766                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6767                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6768                        || eltcode == UNION_TYPE))
6769             {
6770               push_init_level (1);
6771               continue;
6772             }
6773
6774           if (constructor_max_index != 0
6775               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6776                   || integer_all_onesp (constructor_max_index)))
6777             {
6778               pedwarn_init ("excess elements in array initializer");
6779               break;
6780             }
6781
6782           /* Now output the actual element.  */
6783           if (value.value)
6784             {
6785               push_array_bounds (tree_low_cst (constructor_index, 1));
6786               output_init_element (value.value, strict_string,
6787                                    elttype, constructor_index, 1);
6788               RESTORE_SPELLING_DEPTH (constructor_depth);
6789             }
6790
6791           constructor_index
6792             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6793
6794           if (!value.value)
6795             /* If we are doing the bookkeeping for an element that was
6796                directly output as a constructor, we must update
6797                constructor_unfilled_index.  */
6798             constructor_unfilled_index = constructor_index;
6799         }
6800       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6801         {
6802           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6803
6804          /* Do a basic check of initializer size.  Note that vectors
6805             always have a fixed size derived from their type.  */
6806           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6807             {
6808               pedwarn_init ("excess elements in vector initializer");
6809               break;
6810             }
6811
6812           /* Now output the actual element.  */
6813           if (value.value)
6814             output_init_element (value.value, strict_string,
6815                                  elttype, constructor_index, 1);
6816
6817           constructor_index
6818             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6819
6820           if (!value.value)
6821             /* If we are doing the bookkeeping for an element that was
6822                directly output as a constructor, we must update
6823                constructor_unfilled_index.  */
6824             constructor_unfilled_index = constructor_index;
6825         }
6826
6827       /* Handle the sole element allowed in a braced initializer
6828          for a scalar variable.  */
6829       else if (constructor_type != error_mark_node
6830                && constructor_fields == 0)
6831         {
6832           pedwarn_init ("excess elements in scalar initializer");
6833           break;
6834         }
6835       else
6836         {
6837           if (value.value)
6838             output_init_element (value.value, strict_string,
6839                                  constructor_type, NULL_TREE, 1);
6840           constructor_fields = 0;
6841         }
6842
6843       /* Handle range initializers either at this level or anywhere higher
6844          in the designator stack.  */
6845       if (constructor_range_stack)
6846         {
6847           struct constructor_range_stack *p, *range_stack;
6848           int finish = 0;
6849
6850           range_stack = constructor_range_stack;
6851           constructor_range_stack = 0;
6852           while (constructor_stack != range_stack->stack)
6853             {
6854               gcc_assert (constructor_stack->implicit);
6855               process_init_element (pop_init_level (1));
6856             }
6857           for (p = range_stack;
6858                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6859                p = p->prev)
6860             {
6861               gcc_assert (constructor_stack->implicit);
6862               process_init_element (pop_init_level (1));
6863             }
6864
6865           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6866           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6867             finish = 1;
6868
6869           while (1)
6870             {
6871               constructor_index = p->index;
6872               constructor_fields = p->fields;
6873               if (finish && p->range_end && p->index == p->range_start)
6874                 {
6875                   finish = 0;
6876                   p->prev = 0;
6877                 }
6878               p = p->next;
6879               if (!p)
6880                 break;
6881               push_init_level (2);
6882               p->stack = constructor_stack;
6883               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6884                 p->index = p->range_start;
6885             }
6886
6887           if (!finish)
6888             constructor_range_stack = range_stack;
6889           continue;
6890         }
6891
6892       break;
6893     }
6894
6895   constructor_range_stack = 0;
6896 }
6897 \f
6898 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6899    (guaranteed to be 'volatile' or null) and ARGS (represented using
6900    an ASM_EXPR node).  */
6901 tree
6902 build_asm_stmt (tree cv_qualifier, tree args)
6903 {
6904   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6905     ASM_VOLATILE_P (args) = 1;
6906   return add_stmt (args);
6907 }
6908
6909 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6910    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6911    SIMPLE indicates whether there was anything at all after the
6912    string in the asm expression -- asm("blah") and asm("blah" : )
6913    are subtly different.  We use a ASM_EXPR node to represent this.  */
6914 tree
6915 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6916                 bool simple)
6917 {
6918   tree tail;
6919   tree args;
6920   int i;
6921   const char *constraint;
6922   const char **oconstraints;
6923   bool allows_mem, allows_reg, is_inout;
6924   int ninputs, noutputs;
6925
6926   ninputs = list_length (inputs);
6927   noutputs = list_length (outputs);
6928   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6929
6930   string = resolve_asm_operand_names (string, outputs, inputs);
6931
6932   /* Remove output conversions that change the type but not the mode.  */
6933   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6934     {
6935       tree output = TREE_VALUE (tail);
6936
6937       /* ??? Really, this should not be here.  Users should be using a
6938          proper lvalue, dammit.  But there's a long history of using casts
6939          in the output operands.  In cases like longlong.h, this becomes a
6940          primitive form of typechecking -- if the cast can be removed, then
6941          the output operand had a type of the proper width; otherwise we'll
6942          get an error.  Gross, but ...  */
6943       STRIP_NOPS (output);
6944
6945       if (!lvalue_or_else (output, lv_asm))
6946         output = error_mark_node;
6947
6948       if (output != error_mark_node
6949           && (TREE_READONLY (output)
6950               || TYPE_READONLY (TREE_TYPE (output))
6951               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6952                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6953                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6954         readonly_error (output, lv_asm);
6955
6956       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6957       oconstraints[i] = constraint;
6958
6959       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6960                                    &allows_mem, &allows_reg, &is_inout))
6961         {
6962           /* If the operand is going to end up in memory,
6963              mark it addressable.  */
6964           if (!allows_reg && !c_mark_addressable (output))
6965             output = error_mark_node;
6966         }
6967       else
6968         output = error_mark_node;
6969
6970       TREE_VALUE (tail) = output;
6971     }
6972
6973   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6974     {
6975       tree input;
6976
6977       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6978       input = TREE_VALUE (tail);
6979
6980       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6981                                   oconstraints, &allows_mem, &allows_reg))
6982         {
6983           /* If the operand is going to end up in memory,
6984              mark it addressable.  */
6985           if (!allows_reg && allows_mem)
6986             {
6987               /* Strip the nops as we allow this case.  FIXME, this really
6988                  should be rejected or made deprecated.  */
6989               STRIP_NOPS (input);
6990               if (!c_mark_addressable (input))
6991                 input = error_mark_node;
6992           }
6993         }
6994       else
6995         input = error_mark_node;
6996
6997       TREE_VALUE (tail) = input;
6998     }
6999
7000   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7001
7002   /* asm statements without outputs, including simple ones, are treated
7003      as volatile.  */
7004   ASM_INPUT_P (args) = simple;
7005   ASM_VOLATILE_P (args) = (noutputs == 0);
7006
7007   return args;
7008 }
7009 \f
7010 /* Generate a goto statement to LABEL.  */
7011
7012 tree
7013 c_finish_goto_label (tree label)
7014 {
7015   tree decl = lookup_label (label);
7016   if (!decl)
7017     return NULL_TREE;
7018
7019   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7020     {
7021       error ("jump into statement expression");
7022       return NULL_TREE;
7023     }
7024
7025   if (C_DECL_UNJUMPABLE_VM (decl))
7026     {
7027       error ("jump into scope of identifier with variably modified type");
7028       return NULL_TREE;
7029     }
7030
7031   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7032     {
7033       /* No jump from outside this statement expression context, so
7034          record that there is a jump from within this context.  */
7035       struct c_label_list *nlist;
7036       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7037       nlist->next = label_context_stack_se->labels_used;
7038       nlist->label = decl;
7039       label_context_stack_se->labels_used = nlist;
7040     }
7041
7042   if (!C_DECL_UNDEFINABLE_VM (decl))
7043     {
7044       /* No jump from outside this context context of identifiers with
7045          variably modified type, so record that there is a jump from
7046          within this context.  */
7047       struct c_label_list *nlist;
7048       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7049       nlist->next = label_context_stack_vm->labels_used;
7050       nlist->label = decl;
7051       label_context_stack_vm->labels_used = nlist;
7052     }
7053
7054   TREE_USED (decl) = 1;
7055   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7056 }
7057
7058 /* Generate a computed goto statement to EXPR.  */
7059
7060 tree
7061 c_finish_goto_ptr (tree expr)
7062 {
7063   if (pedantic)
7064     pedwarn ("ISO C forbids %<goto *expr;%>");
7065   expr = convert (ptr_type_node, expr);
7066   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7067 }
7068
7069 /* Generate a C `return' statement.  RETVAL is the expression for what
7070    to return, or a null pointer for `return;' with no value.  */
7071
7072 tree
7073 c_finish_return (tree retval)
7074 {
7075   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7076   bool no_warning = false;
7077
7078   if (TREE_THIS_VOLATILE (current_function_decl))
7079     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7080
7081   if (!retval)
7082     {
7083       current_function_returns_null = 1;
7084       if ((warn_return_type || flag_isoc99)
7085           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7086         {
7087           pedwarn_c99 ("%<return%> with no value, in "
7088                        "function returning non-void");
7089           no_warning = true;
7090         }
7091     }
7092   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7093     {
7094       current_function_returns_null = 1;
7095       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7096         pedwarn ("%<return%> with a value, in function returning void");
7097       else if (pedantic)
7098         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7099     }
7100   else
7101     {
7102       tree t = convert_for_assignment (valtype, retval, ic_return,
7103                                        NULL_TREE, NULL_TREE, 0);
7104       tree res = DECL_RESULT (current_function_decl);
7105       tree inner;
7106
7107       current_function_returns_value = 1;
7108       if (t == error_mark_node)
7109         return NULL_TREE;
7110
7111       inner = t = convert (TREE_TYPE (res), t);
7112
7113       /* Strip any conversions, additions, and subtractions, and see if
7114          we are returning the address of a local variable.  Warn if so.  */
7115       while (1)
7116         {
7117           switch (TREE_CODE (inner))
7118             {
7119             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
7120             case PLUS_EXPR:
7121               inner = TREE_OPERAND (inner, 0);
7122               continue;
7123
7124             case MINUS_EXPR:
7125               /* If the second operand of the MINUS_EXPR has a pointer
7126                  type (or is converted from it), this may be valid, so
7127                  don't give a warning.  */
7128               {
7129                 tree op1 = TREE_OPERAND (inner, 1);
7130
7131                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7132                        && (TREE_CODE (op1) == NOP_EXPR
7133                            || TREE_CODE (op1) == NON_LVALUE_EXPR
7134                            || TREE_CODE (op1) == CONVERT_EXPR))
7135                   op1 = TREE_OPERAND (op1, 0);
7136
7137                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7138                   break;
7139
7140                 inner = TREE_OPERAND (inner, 0);
7141                 continue;
7142               }
7143
7144             case ADDR_EXPR:
7145               inner = TREE_OPERAND (inner, 0);
7146
7147               while (REFERENCE_CLASS_P (inner)
7148                      && TREE_CODE (inner) != INDIRECT_REF)
7149                 inner = TREE_OPERAND (inner, 0);
7150
7151               if (DECL_P (inner)
7152                   && !DECL_EXTERNAL (inner)
7153                   && !TREE_STATIC (inner)
7154                   && DECL_CONTEXT (inner) == current_function_decl)
7155                 warning (0, "function returns address of local variable");
7156               break;
7157
7158             default:
7159               break;
7160             }
7161
7162           break;
7163         }
7164
7165       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7166     }
7167
7168   ret_stmt = build_stmt (RETURN_EXPR, retval);
7169   TREE_NO_WARNING (ret_stmt) |= no_warning;
7170   return add_stmt (ret_stmt);
7171 }
7172 \f
7173 struct c_switch {
7174   /* The SWITCH_EXPR being built.  */
7175   tree switch_expr;
7176
7177   /* The original type of the testing expression, i.e. before the
7178      default conversion is applied.  */
7179   tree orig_type;
7180
7181   /* A splay-tree mapping the low element of a case range to the high
7182      element, or NULL_TREE if there is no high element.  Used to
7183      determine whether or not a new case label duplicates an old case
7184      label.  We need a tree, rather than simply a hash table, because
7185      of the GNU case range extension.  */
7186   splay_tree cases;
7187
7188   /* Number of nested statement expressions within this switch
7189      statement; if nonzero, case and default labels may not
7190      appear.  */
7191   unsigned int blocked_stmt_expr;
7192
7193   /* Scope of outermost declarations of identifiers with variably
7194      modified type within this switch statement; if nonzero, case and
7195      default labels may not appear.  */
7196   unsigned int blocked_vm;
7197
7198   /* The next node on the stack.  */
7199   struct c_switch *next;
7200 };
7201
7202 /* A stack of the currently active switch statements.  The innermost
7203    switch statement is on the top of the stack.  There is no need to
7204    mark the stack for garbage collection because it is only active
7205    during the processing of the body of a function, and we never
7206    collect at that point.  */
7207
7208 struct c_switch *c_switch_stack;
7209
7210 /* Start a C switch statement, testing expression EXP.  Return the new
7211    SWITCH_EXPR.  */
7212
7213 tree
7214 c_start_case (tree exp)
7215 {
7216   tree orig_type = error_mark_node;
7217   struct c_switch *cs;
7218
7219   if (exp != error_mark_node)
7220     {
7221       orig_type = TREE_TYPE (exp);
7222
7223       if (!INTEGRAL_TYPE_P (orig_type))
7224         {
7225           if (orig_type != error_mark_node)
7226             {
7227               error ("switch quantity not an integer");
7228               orig_type = error_mark_node;
7229             }
7230           exp = integer_zero_node;
7231         }
7232       else
7233         {
7234           tree type = TYPE_MAIN_VARIANT (orig_type);
7235
7236           if (!in_system_header
7237               && (type == long_integer_type_node
7238                   || type == long_unsigned_type_node))
7239             warning (OPT_Wtraditional, "%<long%> switch expression not "
7240                      "converted to %<int%> in ISO C");
7241
7242           exp = default_conversion (exp);
7243         }
7244     }
7245
7246   /* Add this new SWITCH_EXPR to the stack.  */
7247   cs = XNEW (struct c_switch);
7248   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7249   cs->orig_type = orig_type;
7250   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7251   cs->blocked_stmt_expr = 0;
7252   cs->blocked_vm = 0;
7253   cs->next = c_switch_stack;
7254   c_switch_stack = cs;
7255
7256   return add_stmt (cs->switch_expr);
7257 }
7258
7259 /* Process a case label.  */
7260
7261 tree
7262 do_case (tree low_value, tree high_value)
7263 {
7264   tree label = NULL_TREE;
7265
7266   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7267       && !c_switch_stack->blocked_vm)
7268     {
7269       label = c_add_case_label (c_switch_stack->cases,
7270                                 SWITCH_COND (c_switch_stack->switch_expr),
7271                                 c_switch_stack->orig_type,
7272                                 low_value, high_value);
7273       if (label == error_mark_node)
7274         label = NULL_TREE;
7275     }
7276   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7277     {
7278       if (low_value)
7279         error ("case label in statement expression not containing "
7280                "enclosing switch statement");
7281       else
7282         error ("%<default%> label in statement expression not containing "
7283                "enclosing switch statement");
7284     }
7285   else if (c_switch_stack && c_switch_stack->blocked_vm)
7286     {
7287       if (low_value)
7288         error ("case label in scope of identifier with variably modified "
7289                "type not containing enclosing switch statement");
7290       else
7291         error ("%<default%> label in scope of identifier with variably "
7292                "modified type not containing enclosing switch statement");
7293     }
7294   else if (low_value)
7295     error ("case label not within a switch statement");
7296   else
7297     error ("%<default%> label not within a switch statement");
7298
7299   return label;
7300 }
7301
7302 /* Finish the switch statement.  */
7303
7304 void
7305 c_finish_case (tree body)
7306 {
7307   struct c_switch *cs = c_switch_stack;
7308   location_t switch_location;
7309
7310   SWITCH_BODY (cs->switch_expr) = body;
7311
7312   /* We must not be within a statement expression nested in the switch
7313      at this point; we might, however, be within the scope of an
7314      identifier with variably modified type nested in the switch.  */
7315   gcc_assert (!cs->blocked_stmt_expr);
7316
7317   /* Emit warnings as needed.  */
7318   if (EXPR_HAS_LOCATION (cs->switch_expr))
7319     switch_location = EXPR_LOCATION (cs->switch_expr);
7320   else
7321     switch_location = input_location;
7322   c_do_switch_warnings (cs->cases, switch_location,
7323                         TREE_TYPE (cs->switch_expr),
7324                         SWITCH_COND (cs->switch_expr));
7325
7326   /* Pop the stack.  */
7327   c_switch_stack = cs->next;
7328   splay_tree_delete (cs->cases);
7329   XDELETE (cs);
7330 }
7331 \f
7332 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7333    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7334    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7335    statement, and was not surrounded with parenthesis.  */
7336
7337 void
7338 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7339                   tree else_block, bool nested_if)
7340 {
7341   tree stmt;
7342
7343   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7344   if (warn_parentheses && nested_if && else_block == NULL)
7345     {
7346       tree inner_if = then_block;
7347
7348       /* We know from the grammar productions that there is an IF nested
7349          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7350          it might not be exactly THEN_BLOCK, but should be the last
7351          non-container statement within.  */
7352       while (1)
7353         switch (TREE_CODE (inner_if))
7354           {
7355           case COND_EXPR:
7356             goto found;
7357           case BIND_EXPR:
7358             inner_if = BIND_EXPR_BODY (inner_if);
7359             break;
7360           case STATEMENT_LIST:
7361             inner_if = expr_last (then_block);
7362             break;
7363           case TRY_FINALLY_EXPR:
7364           case TRY_CATCH_EXPR:
7365             inner_if = TREE_OPERAND (inner_if, 0);
7366             break;
7367           default:
7368             gcc_unreachable ();
7369           }
7370     found:
7371
7372       if (COND_EXPR_ELSE (inner_if))
7373          warning (OPT_Wparentheses,
7374                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7375                   &if_locus);
7376     }
7377
7378   empty_if_body_warning (then_block, else_block);
7379
7380   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7381   SET_EXPR_LOCATION (stmt, if_locus);
7382   add_stmt (stmt);
7383 }
7384
7385 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7386    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7387    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7388    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7389    the continue label.  Everything is allowed to be NULL.  */
7390
7391 void
7392 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7393                tree blab, tree clab, bool cond_is_first)
7394 {
7395   tree entry = NULL, exit = NULL, t;
7396
7397   /* If the condition is zero don't generate a loop construct.  */
7398   if (cond && integer_zerop (cond))
7399     {
7400       if (cond_is_first)
7401         {
7402           t = build_and_jump (&blab);
7403           SET_EXPR_LOCATION (t, start_locus);
7404           add_stmt (t);
7405         }
7406     }
7407   else
7408     {
7409       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7410
7411       /* If we have an exit condition, then we build an IF with gotos either
7412          out of the loop, or to the top of it.  If there's no exit condition,
7413          then we just build a jump back to the top.  */
7414       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7415
7416       if (cond && !integer_nonzerop (cond))
7417         {
7418           /* Canonicalize the loop condition to the end.  This means
7419              generating a branch to the loop condition.  Reuse the
7420              continue label, if possible.  */
7421           if (cond_is_first)
7422             {
7423               if (incr || !clab)
7424                 {
7425                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7426                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7427                 }
7428               else
7429                 t = build1 (GOTO_EXPR, void_type_node, clab);
7430               SET_EXPR_LOCATION (t, start_locus);
7431               add_stmt (t);
7432             }
7433
7434           t = build_and_jump (&blab);
7435           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7436           if (cond_is_first)
7437             SET_EXPR_LOCATION (exit, start_locus);
7438           else
7439             SET_EXPR_LOCATION (exit, input_location);
7440         }
7441
7442       add_stmt (top);
7443     }
7444
7445   if (body)
7446     add_stmt (body);
7447   if (clab)
7448     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7449   if (incr)
7450     add_stmt (incr);
7451   if (entry)
7452     add_stmt (entry);
7453   if (exit)
7454     add_stmt (exit);
7455   if (blab)
7456     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7457 }
7458
7459 tree
7460 c_finish_bc_stmt (tree *label_p, bool is_break)
7461 {
7462   bool skip;
7463   tree label = *label_p;
7464
7465   /* In switch statements break is sometimes stylistically used after
7466      a return statement.  This can lead to spurious warnings about
7467      control reaching the end of a non-void function when it is
7468      inlined.  Note that we are calling block_may_fallthru with
7469      language specific tree nodes; this works because
7470      block_may_fallthru returns true when given something it does not
7471      understand.  */
7472   skip = !block_may_fallthru (cur_stmt_list);
7473
7474   if (!label)
7475     {
7476       if (!skip)
7477         *label_p = label = create_artificial_label ();
7478     }
7479   else if (TREE_CODE (label) == LABEL_DECL)
7480     ;
7481   else switch (TREE_INT_CST_LOW (label))
7482     {
7483     case 0:
7484       if (is_break)
7485         error ("break statement not within loop or switch");
7486       else
7487         error ("continue statement not within a loop");
7488       return NULL_TREE;
7489
7490     case 1:
7491       gcc_assert (is_break);
7492       error ("break statement used with OpenMP for loop");
7493       return NULL_TREE;
7494
7495     default:
7496       gcc_unreachable ();
7497     }
7498
7499   if (skip)
7500     return NULL_TREE;
7501
7502   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7503 }
7504
7505 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7506
7507 static void
7508 emit_side_effect_warnings (tree expr)
7509 {
7510   if (expr == error_mark_node)
7511     ;
7512   else if (!TREE_SIDE_EFFECTS (expr))
7513     {
7514       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7515         warning (OPT_Wunused_value, "%Hstatement with no effect",
7516                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7517     }
7518   else
7519     warn_if_unused_value (expr, input_location);
7520 }
7521
7522 /* Process an expression as if it were a complete statement.  Emit
7523    diagnostics, but do not call ADD_STMT.  */
7524
7525 tree
7526 c_process_expr_stmt (tree expr)
7527 {
7528   if (!expr)
7529     return NULL_TREE;
7530
7531   if (warn_sequence_point)
7532     verify_sequence_points (expr);
7533
7534   if (TREE_TYPE (expr) != error_mark_node
7535       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7536       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7537     error ("expression statement has incomplete type");
7538
7539   /* If we're not processing a statement expression, warn about unused values.
7540      Warnings for statement expressions will be emitted later, once we figure
7541      out which is the result.  */
7542   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7543       && warn_unused_value)
7544     emit_side_effect_warnings (expr);
7545
7546   /* If the expression is not of a type to which we cannot assign a line
7547      number, wrap the thing in a no-op NOP_EXPR.  */
7548   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7549     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7550
7551   if (CAN_HAVE_LOCATION_P (expr))
7552     SET_EXPR_LOCATION (expr, input_location);
7553
7554   return expr;
7555 }
7556
7557 /* Emit an expression as a statement.  */
7558
7559 tree
7560 c_finish_expr_stmt (tree expr)
7561 {
7562   if (expr)
7563     return add_stmt (c_process_expr_stmt (expr));
7564   else
7565     return NULL;
7566 }
7567
7568 /* Do the opposite and emit a statement as an expression.  To begin,
7569    create a new binding level and return it.  */
7570
7571 tree
7572 c_begin_stmt_expr (void)
7573 {
7574   tree ret;
7575   struct c_label_context_se *nstack;
7576   struct c_label_list *glist;
7577
7578   /* We must force a BLOCK for this level so that, if it is not expanded
7579      later, there is a way to turn off the entire subtree of blocks that
7580      are contained in it.  */
7581   keep_next_level ();
7582   ret = c_begin_compound_stmt (true);
7583   if (c_switch_stack)
7584     {
7585       c_switch_stack->blocked_stmt_expr++;
7586       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7587     }
7588   for (glist = label_context_stack_se->labels_used;
7589        glist != NULL;
7590        glist = glist->next)
7591     {
7592       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7593     }
7594   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7595   nstack->labels_def = NULL;
7596   nstack->labels_used = NULL;
7597   nstack->next = label_context_stack_se;
7598   label_context_stack_se = nstack;
7599
7600   /* Mark the current statement list as belonging to a statement list.  */
7601   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7602
7603   return ret;
7604 }
7605
7606 tree
7607 c_finish_stmt_expr (tree body)
7608 {
7609   tree last, type, tmp, val;
7610   tree *last_p;
7611   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7612
7613   body = c_end_compound_stmt (body, true);
7614   if (c_switch_stack)
7615     {
7616       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7617       c_switch_stack->blocked_stmt_expr--;
7618     }
7619   /* It is no longer possible to jump to labels defined within this
7620      statement expression.  */
7621   for (dlist = label_context_stack_se->labels_def;
7622        dlist != NULL;
7623        dlist = dlist->next)
7624     {
7625       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7626     }
7627   /* It is again possible to define labels with a goto just outside
7628      this statement expression.  */
7629   for (glist = label_context_stack_se->next->labels_used;
7630        glist != NULL;
7631        glist = glist->next)
7632     {
7633       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7634       glist_prev = glist;
7635     }
7636   if (glist_prev != NULL)
7637     glist_prev->next = label_context_stack_se->labels_used;
7638   else
7639     label_context_stack_se->next->labels_used
7640       = label_context_stack_se->labels_used;
7641   label_context_stack_se = label_context_stack_se->next;
7642
7643   /* Locate the last statement in BODY.  See c_end_compound_stmt
7644      about always returning a BIND_EXPR.  */
7645   last_p = &BIND_EXPR_BODY (body);
7646   last = BIND_EXPR_BODY (body);
7647
7648  continue_searching:
7649   if (TREE_CODE (last) == STATEMENT_LIST)
7650     {
7651       tree_stmt_iterator i;
7652
7653       /* This can happen with degenerate cases like ({ }).  No value.  */
7654       if (!TREE_SIDE_EFFECTS (last))
7655         return body;
7656
7657       /* If we're supposed to generate side effects warnings, process
7658          all of the statements except the last.  */
7659       if (warn_unused_value)
7660         {
7661           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7662             emit_side_effect_warnings (tsi_stmt (i));
7663         }
7664       else
7665         i = tsi_last (last);
7666       last_p = tsi_stmt_ptr (i);
7667       last = *last_p;
7668     }
7669
7670   /* If the end of the list is exception related, then the list was split
7671      by a call to push_cleanup.  Continue searching.  */
7672   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7673       || TREE_CODE (last) == TRY_CATCH_EXPR)
7674     {
7675       last_p = &TREE_OPERAND (last, 0);
7676       last = *last_p;
7677       goto continue_searching;
7678     }
7679
7680   /* In the case that the BIND_EXPR is not necessary, return the
7681      expression out from inside it.  */
7682   if (last == error_mark_node
7683       || (last == BIND_EXPR_BODY (body)
7684           && BIND_EXPR_VARS (body) == NULL))
7685     {
7686       /* Do not warn if the return value of a statement expression is
7687          unused.  */
7688       if (CAN_HAVE_LOCATION_P (last))
7689         TREE_NO_WARNING (last) = 1;
7690       return last;
7691     }
7692
7693   /* Extract the type of said expression.  */
7694   type = TREE_TYPE (last);
7695
7696   /* If we're not returning a value at all, then the BIND_EXPR that
7697      we already have is a fine expression to return.  */
7698   if (!type || VOID_TYPE_P (type))
7699     return body;
7700
7701   /* Now that we've located the expression containing the value, it seems
7702      silly to make voidify_wrapper_expr repeat the process.  Create a
7703      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7704   tmp = create_tmp_var_raw (type, NULL);
7705
7706   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7707      tree_expr_nonnegative_p giving up immediately.  */
7708   val = last;
7709   if (TREE_CODE (val) == NOP_EXPR
7710       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7711     val = TREE_OPERAND (val, 0);
7712
7713   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7714   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7715
7716   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7717 }
7718
7719 /* Begin the scope of an identifier of variably modified type, scope
7720    number SCOPE.  Jumping from outside this scope to inside it is not
7721    permitted.  */
7722
7723 void
7724 c_begin_vm_scope (unsigned int scope)
7725 {
7726   struct c_label_context_vm *nstack;
7727   struct c_label_list *glist;
7728
7729   gcc_assert (scope > 0);
7730
7731   /* At file_scope, we don't have to do any processing.  */
7732   if (label_context_stack_vm == NULL)
7733     return;
7734
7735   if (c_switch_stack && !c_switch_stack->blocked_vm)
7736     c_switch_stack->blocked_vm = scope;
7737   for (glist = label_context_stack_vm->labels_used;
7738        glist != NULL;
7739        glist = glist->next)
7740     {
7741       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7742     }
7743   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7744   nstack->labels_def = NULL;
7745   nstack->labels_used = NULL;
7746   nstack->scope = scope;
7747   nstack->next = label_context_stack_vm;
7748   label_context_stack_vm = nstack;
7749 }
7750
7751 /* End a scope which may contain identifiers of variably modified
7752    type, scope number SCOPE.  */
7753
7754 void
7755 c_end_vm_scope (unsigned int scope)
7756 {
7757   if (label_context_stack_vm == NULL)
7758     return;
7759   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7760     c_switch_stack->blocked_vm = 0;
7761   /* We may have a number of nested scopes of identifiers with
7762      variably modified type, all at this depth.  Pop each in turn.  */
7763   while (label_context_stack_vm->scope == scope)
7764     {
7765       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7766
7767       /* It is no longer possible to jump to labels defined within this
7768          scope.  */
7769       for (dlist = label_context_stack_vm->labels_def;
7770            dlist != NULL;
7771            dlist = dlist->next)
7772         {
7773           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7774         }
7775       /* It is again possible to define labels with a goto just outside
7776          this scope.  */
7777       for (glist = label_context_stack_vm->next->labels_used;
7778            glist != NULL;
7779            glist = glist->next)
7780         {
7781           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7782           glist_prev = glist;
7783         }
7784       if (glist_prev != NULL)
7785         glist_prev->next = label_context_stack_vm->labels_used;
7786       else
7787         label_context_stack_vm->next->labels_used
7788           = label_context_stack_vm->labels_used;
7789       label_context_stack_vm = label_context_stack_vm->next;
7790     }
7791 }
7792 \f
7793 /* Begin and end compound statements.  This is as simple as pushing
7794    and popping new statement lists from the tree.  */
7795
7796 tree
7797 c_begin_compound_stmt (bool do_scope)
7798 {
7799   tree stmt = push_stmt_list ();
7800   if (do_scope)
7801     push_scope ();
7802   return stmt;
7803 }
7804
7805 tree
7806 c_end_compound_stmt (tree stmt, bool do_scope)
7807 {
7808   tree block = NULL;
7809
7810   if (do_scope)
7811     {
7812       if (c_dialect_objc ())
7813         objc_clear_super_receiver ();
7814       block = pop_scope ();
7815     }
7816
7817   stmt = pop_stmt_list (stmt);
7818   stmt = c_build_bind_expr (block, stmt);
7819
7820   /* If this compound statement is nested immediately inside a statement
7821      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7822      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7823      STATEMENT_LISTs merge, and thus we can lose track of what statement
7824      was really last.  */
7825   if (cur_stmt_list
7826       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7827       && TREE_CODE (stmt) != BIND_EXPR)
7828     {
7829       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7830       TREE_SIDE_EFFECTS (stmt) = 1;
7831     }
7832
7833   return stmt;
7834 }
7835
7836 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7837    when the current scope is exited.  EH_ONLY is true when this is not
7838    meant to apply to normal control flow transfer.  */
7839
7840 void
7841 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7842 {
7843   enum tree_code code;
7844   tree stmt, list;
7845   bool stmt_expr;
7846
7847   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7848   stmt = build_stmt (code, NULL, cleanup);
7849   add_stmt (stmt);
7850   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7851   list = push_stmt_list ();
7852   TREE_OPERAND (stmt, 0) = list;
7853   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7854 }
7855 \f
7856 /* Build a binary-operation expression without default conversions.
7857    CODE is the kind of expression to build.
7858    This function differs from `build' in several ways:
7859    the data type of the result is computed and recorded in it,
7860    warnings are generated if arg data types are invalid,
7861    special handling for addition and subtraction of pointers is known,
7862    and some optimization is done (operations on narrow ints
7863    are done in the narrower type when that gives the same result).
7864    Constant folding is also done before the result is returned.
7865
7866    Note that the operands will never have enumeral types, or function
7867    or array types, because either they will have the default conversions
7868    performed or they have both just been converted to some other type in which
7869    the arithmetic is to be done.  */
7870
7871 tree
7872 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7873                  int convert_p)
7874 {
7875   tree type0, type1;
7876   enum tree_code code0, code1;
7877   tree op0, op1;
7878   const char *invalid_op_diag;
7879
7880   /* Expression code to give to the expression when it is built.
7881      Normally this is CODE, which is what the caller asked for,
7882      but in some special cases we change it.  */
7883   enum tree_code resultcode = code;
7884
7885   /* Data type in which the computation is to be performed.
7886      In the simplest cases this is the common type of the arguments.  */
7887   tree result_type = NULL;
7888
7889   /* Nonzero means operands have already been type-converted
7890      in whatever way is necessary.
7891      Zero means they need to be converted to RESULT_TYPE.  */
7892   int converted = 0;
7893
7894   /* Nonzero means create the expression with this type, rather than
7895      RESULT_TYPE.  */
7896   tree build_type = 0;
7897
7898   /* Nonzero means after finally constructing the expression
7899      convert it to this type.  */
7900   tree final_type = 0;
7901
7902   /* Nonzero if this is an operation like MIN or MAX which can
7903      safely be computed in short if both args are promoted shorts.
7904      Also implies COMMON.
7905      -1 indicates a bitwise operation; this makes a difference
7906      in the exact conditions for when it is safe to do the operation
7907      in a narrower mode.  */
7908   int shorten = 0;
7909
7910   /* Nonzero if this is a comparison operation;
7911      if both args are promoted shorts, compare the original shorts.
7912      Also implies COMMON.  */
7913   int short_compare = 0;
7914
7915   /* Nonzero if this is a right-shift operation, which can be computed on the
7916      original short and then promoted if the operand is a promoted short.  */
7917   int short_shift = 0;
7918
7919   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7920   int common = 0;
7921
7922   /* True means types are compatible as far as ObjC is concerned.  */
7923   bool objc_ok;
7924
7925   if (convert_p)
7926     {
7927       op0 = default_conversion (orig_op0);
7928       op1 = default_conversion (orig_op1);
7929     }
7930   else
7931     {
7932       op0 = orig_op0;
7933       op1 = orig_op1;
7934     }
7935
7936   type0 = TREE_TYPE (op0);
7937   type1 = TREE_TYPE (op1);
7938
7939   /* The expression codes of the data types of the arguments tell us
7940      whether the arguments are integers, floating, pointers, etc.  */
7941   code0 = TREE_CODE (type0);
7942   code1 = TREE_CODE (type1);
7943
7944   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7945   STRIP_TYPE_NOPS (op0);
7946   STRIP_TYPE_NOPS (op1);
7947
7948   /* If an error was already reported for one of the arguments,
7949      avoid reporting another error.  */
7950
7951   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7952     return error_mark_node;
7953
7954   if ((invalid_op_diag
7955        = targetm.invalid_binary_op (code, type0, type1)))
7956     {
7957       error (invalid_op_diag);
7958       return error_mark_node;
7959     }
7960
7961   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7962
7963   switch (code)
7964     {
7965     case PLUS_EXPR:
7966       /* Handle the pointer + int case.  */
7967       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7968         return pointer_int_sum (PLUS_EXPR, op0, op1);
7969       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7970         return pointer_int_sum (PLUS_EXPR, op1, op0);
7971       else
7972         common = 1;
7973       break;
7974
7975     case MINUS_EXPR:
7976       /* Subtraction of two similar pointers.
7977          We must subtract them as integers, then divide by object size.  */
7978       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7979           && comp_target_types (type0, type1))
7980         return pointer_diff (op0, op1);
7981       /* Handle pointer minus int.  Just like pointer plus int.  */
7982       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7983         return pointer_int_sum (MINUS_EXPR, op0, op1);
7984       else
7985         common = 1;
7986       break;
7987
7988     case MULT_EXPR:
7989       common = 1;
7990       break;
7991
7992     case TRUNC_DIV_EXPR:
7993     case CEIL_DIV_EXPR:
7994     case FLOOR_DIV_EXPR:
7995     case ROUND_DIV_EXPR:
7996     case EXACT_DIV_EXPR:
7997       warn_for_div_by_zero (op1);
7998
7999       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8000            || code0 == FIXED_POINT_TYPE
8001            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8002           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8003               || code1 == FIXED_POINT_TYPE
8004               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8005         {
8006           enum tree_code tcode0 = code0, tcode1 = code1;
8007
8008           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8009             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8010           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8011             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8012
8013           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8014               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8015             resultcode = RDIV_EXPR;
8016           else
8017             /* Although it would be tempting to shorten always here, that
8018                loses on some targets, since the modulo instruction is
8019                undefined if the quotient can't be represented in the
8020                computation mode.  We shorten only if unsigned or if
8021                dividing by something we know != -1.  */
8022             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8023                        || (TREE_CODE (op1) == INTEGER_CST
8024                            && !integer_all_onesp (op1)));
8025           common = 1;
8026         }
8027       break;
8028
8029     case BIT_AND_EXPR:
8030     case BIT_IOR_EXPR:
8031     case BIT_XOR_EXPR:
8032       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8033         shorten = -1;
8034       /* Allow vector types which are not floating point types.   */
8035       else if (code0 == VECTOR_TYPE
8036                && code1 == VECTOR_TYPE
8037                && !VECTOR_FLOAT_TYPE_P (type0)
8038                && !VECTOR_FLOAT_TYPE_P (type1))
8039         common = 1;
8040       break;
8041
8042     case TRUNC_MOD_EXPR:
8043     case FLOOR_MOD_EXPR:
8044       warn_for_div_by_zero (op1);
8045
8046       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8047         {
8048           /* Although it would be tempting to shorten always here, that loses
8049              on some targets, since the modulo instruction is undefined if the
8050              quotient can't be represented in the computation mode.  We shorten
8051              only if unsigned or if dividing by something we know != -1.  */
8052           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8053                      || (TREE_CODE (op1) == INTEGER_CST
8054                          && !integer_all_onesp (op1)));
8055           common = 1;
8056         }
8057       break;
8058
8059     case TRUTH_ANDIF_EXPR:
8060     case TRUTH_ORIF_EXPR:
8061     case TRUTH_AND_EXPR:
8062     case TRUTH_OR_EXPR:
8063     case TRUTH_XOR_EXPR:
8064       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8065            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8066            || code0 == FIXED_POINT_TYPE)
8067           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8068               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8069               || code1 == FIXED_POINT_TYPE))
8070         {
8071           /* Result of these operations is always an int,
8072              but that does not mean the operands should be
8073              converted to ints!  */
8074           result_type = integer_type_node;
8075           op0 = c_common_truthvalue_conversion (op0);
8076           op1 = c_common_truthvalue_conversion (op1);
8077           converted = 1;
8078         }
8079       break;
8080
8081       /* Shift operations: result has same type as first operand;
8082          always convert second operand to int.
8083          Also set SHORT_SHIFT if shifting rightward.  */
8084
8085     case RSHIFT_EXPR:
8086       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8087           && code1 == INTEGER_TYPE)
8088         {
8089           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8090             {
8091               if (tree_int_cst_sgn (op1) < 0)
8092                 warning (0, "right shift count is negative");
8093               else
8094                 {
8095                   if (!integer_zerop (op1))
8096                     short_shift = 1;
8097
8098                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8099                     warning (0, "right shift count >= width of type");
8100                 }
8101             }
8102
8103           /* Use the type of the value to be shifted.  */
8104           result_type = type0;
8105           /* Convert the shift-count to an integer, regardless of size
8106              of value being shifted.  */
8107           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8108             op1 = convert (integer_type_node, op1);
8109           /* Avoid converting op1 to result_type later.  */
8110           converted = 1;
8111         }
8112       break;
8113
8114     case LSHIFT_EXPR:
8115       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8116           && code1 == INTEGER_TYPE)
8117         {
8118           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8119             {
8120               if (tree_int_cst_sgn (op1) < 0)
8121                 warning (0, "left shift count is negative");
8122
8123               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8124                 warning (0, "left shift count >= width of type");
8125             }
8126
8127           /* Use the type of the value to be shifted.  */
8128           result_type = type0;
8129           /* Convert the shift-count to an integer, regardless of size
8130              of value being shifted.  */
8131           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8132             op1 = convert (integer_type_node, op1);
8133           /* Avoid converting op1 to result_type later.  */
8134           converted = 1;
8135         }
8136       break;
8137
8138     case EQ_EXPR:
8139     case NE_EXPR:
8140       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
8141         warning (OPT_Wfloat_equal,
8142                  "comparing floating point with == or != is unsafe");
8143       /* Result of comparison is always int,
8144          but don't convert the args to int!  */
8145       build_type = integer_type_node;
8146       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8147            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8148           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8149               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8150         short_compare = 1;
8151       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8152         {
8153           tree tt0 = TREE_TYPE (type0);
8154           tree tt1 = TREE_TYPE (type1);
8155           /* Anything compares with void *.  void * compares with anything.
8156              Otherwise, the targets must be compatible
8157              and both must be object or both incomplete.  */
8158           if (comp_target_types (type0, type1))
8159             result_type = common_pointer_type (type0, type1);
8160           else if (VOID_TYPE_P (tt0))
8161             {
8162               /* op0 != orig_op0 detects the case of something
8163                  whose value is 0 but which isn't a valid null ptr const.  */
8164               if (pedantic && !null_pointer_constant_p (orig_op0)
8165                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8166                 pedwarn ("ISO C forbids comparison of %<void *%>"
8167                          " with function pointer");
8168             }
8169           else if (VOID_TYPE_P (tt1))
8170             {
8171               if (pedantic && !null_pointer_constant_p (orig_op1)
8172                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8173                 pedwarn ("ISO C forbids comparison of %<void *%>"
8174                          " with function pointer");
8175             }
8176           else
8177             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8178             if (!objc_ok)
8179               pedwarn ("comparison of distinct pointer types lacks a cast");
8180
8181           if (result_type == NULL_TREE)
8182             result_type = ptr_type_node;
8183         }
8184       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8185         {
8186           if (TREE_CODE (op0) == ADDR_EXPR
8187               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8188             warning (OPT_Waddress, "the address of %qD will never be NULL",
8189                      TREE_OPERAND (op0, 0));
8190           result_type = type0;
8191         }
8192       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8193         {
8194           if (TREE_CODE (op1) == ADDR_EXPR
8195               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8196             warning (OPT_Waddress, "the address of %qD will never be NULL",
8197                      TREE_OPERAND (op1, 0));
8198           result_type = type1;
8199         }
8200       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8201         {
8202           result_type = type0;
8203           pedwarn ("comparison between pointer and integer");
8204         }
8205       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8206         {
8207           result_type = type1;
8208           pedwarn ("comparison between pointer and integer");
8209         }
8210       break;
8211
8212     case LE_EXPR:
8213     case GE_EXPR:
8214     case LT_EXPR:
8215     case GT_EXPR:
8216       build_type = integer_type_node;
8217       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8218            || code0 == FIXED_POINT_TYPE)
8219           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8220               || code1 == FIXED_POINT_TYPE))
8221         short_compare = 1;
8222       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8223         {
8224           if (comp_target_types (type0, type1))
8225             {
8226               result_type = common_pointer_type (type0, type1);
8227               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8228                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8229                 pedwarn ("comparison of complete and incomplete pointers");
8230               else if (pedantic
8231                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8232                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8233             }
8234           else
8235             {
8236               result_type = ptr_type_node;
8237               pedwarn ("comparison of distinct pointer types lacks a cast");
8238             }
8239         }
8240       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8241         {
8242           result_type = type0;
8243           if (pedantic || extra_warnings)
8244             pedwarn ("ordered comparison of pointer with integer zero");
8245         }
8246       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8247         {
8248           result_type = type1;
8249           if (pedantic)
8250             pedwarn ("ordered comparison of pointer with integer zero");
8251         }
8252       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8253         {
8254           result_type = type0;
8255           pedwarn ("comparison between pointer and integer");
8256         }
8257       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8258         {
8259           result_type = type1;
8260           pedwarn ("comparison between pointer and integer");
8261         }
8262       break;
8263
8264     default:
8265       gcc_unreachable ();
8266     }
8267
8268   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8269     return error_mark_node;
8270
8271   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8272       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8273           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8274                                                     TREE_TYPE (type1))))
8275     {
8276       binary_op_error (code, type0, type1);
8277       return error_mark_node;
8278     }
8279
8280   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8281        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8282       &&
8283       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8284        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8285     {
8286       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8287
8288       if (shorten || common || short_compare)
8289         {
8290           result_type = c_common_type (type0, type1);
8291           if (result_type == error_mark_node)
8292             return error_mark_node;
8293         }
8294
8295       /* For certain operations (which identify themselves by shorten != 0)
8296          if both args were extended from the same smaller type,
8297          do the arithmetic in that type and then extend.
8298
8299          shorten !=0 and !=1 indicates a bitwise operation.
8300          For them, this optimization is safe only if
8301          both args are zero-extended or both are sign-extended.
8302          Otherwise, we might change the result.
8303          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8304          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8305
8306       if (shorten && none_complex)
8307         {
8308           int unsigned0, unsigned1;
8309           tree arg0, arg1;
8310           int uns;
8311           tree type;
8312
8313           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8314              excessive narrowing when we call get_narrower below.  For
8315              example, suppose that OP0 is of unsigned int extended
8316              from signed char and that RESULT_TYPE is long long int.
8317              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8318              like
8319
8320                (long long int) (unsigned int) signed_char
8321
8322              which get_narrower would narrow down to
8323
8324                (unsigned int) signed char
8325
8326              If we do not cast OP0 first, get_narrower would return
8327              signed_char, which is inconsistent with the case of the
8328              explicit cast.  */
8329           op0 = convert (result_type, op0);
8330           op1 = convert (result_type, op1);
8331
8332           arg0 = get_narrower (op0, &unsigned0);
8333           arg1 = get_narrower (op1, &unsigned1);
8334
8335           /* UNS is 1 if the operation to be done is an unsigned one.  */
8336           uns = TYPE_UNSIGNED (result_type);
8337
8338           final_type = result_type;
8339
8340           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8341              but it *requires* conversion to FINAL_TYPE.  */
8342
8343           if ((TYPE_PRECISION (TREE_TYPE (op0))
8344                == TYPE_PRECISION (TREE_TYPE (arg0)))
8345               && TREE_TYPE (op0) != final_type)
8346             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8347           if ((TYPE_PRECISION (TREE_TYPE (op1))
8348                == TYPE_PRECISION (TREE_TYPE (arg1)))
8349               && TREE_TYPE (op1) != final_type)
8350             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8351
8352           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8353
8354           /* For bitwise operations, signedness of nominal type
8355              does not matter.  Consider only how operands were extended.  */
8356           if (shorten == -1)
8357             uns = unsigned0;
8358
8359           /* Note that in all three cases below we refrain from optimizing
8360              an unsigned operation on sign-extended args.
8361              That would not be valid.  */
8362
8363           /* Both args variable: if both extended in same way
8364              from same width, do it in that width.
8365              Do it unsigned if args were zero-extended.  */
8366           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8367                < TYPE_PRECISION (result_type))
8368               && (TYPE_PRECISION (TREE_TYPE (arg1))
8369                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8370               && unsigned0 == unsigned1
8371               && (unsigned0 || !uns))
8372             result_type
8373               = c_common_signed_or_unsigned_type
8374               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8375           else if (TREE_CODE (arg0) == INTEGER_CST
8376                    && (unsigned1 || !uns)
8377                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8378                        < TYPE_PRECISION (result_type))
8379                    && (type
8380                        = c_common_signed_or_unsigned_type (unsigned1,
8381                                                            TREE_TYPE (arg1)))
8382                    && !POINTER_TYPE_P (type)
8383                    && int_fits_type_p (arg0, type))
8384             result_type = type;
8385           else if (TREE_CODE (arg1) == INTEGER_CST
8386                    && (unsigned0 || !uns)
8387                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8388                        < TYPE_PRECISION (result_type))
8389                    && (type
8390                        = c_common_signed_or_unsigned_type (unsigned0,
8391                                                            TREE_TYPE (arg0)))
8392                    && !POINTER_TYPE_P (type)
8393                    && int_fits_type_p (arg1, type))
8394             result_type = type;
8395         }
8396
8397       /* Shifts can be shortened if shifting right.  */
8398
8399       if (short_shift)
8400         {
8401           int unsigned_arg;
8402           tree arg0 = get_narrower (op0, &unsigned_arg);
8403
8404           final_type = result_type;
8405
8406           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8407             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8408
8409           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8410               /* We can shorten only if the shift count is less than the
8411                  number of bits in the smaller type size.  */
8412               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8413               /* We cannot drop an unsigned shift after sign-extension.  */
8414               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8415             {
8416               /* Do an unsigned shift if the operand was zero-extended.  */
8417               result_type
8418                 = c_common_signed_or_unsigned_type (unsigned_arg,
8419                                                     TREE_TYPE (arg0));
8420               /* Convert value-to-be-shifted to that type.  */
8421               if (TREE_TYPE (op0) != result_type)
8422                 op0 = convert (result_type, op0);
8423               converted = 1;
8424             }
8425         }
8426
8427       /* Comparison operations are shortened too but differently.
8428          They identify themselves by setting short_compare = 1.  */
8429
8430       if (short_compare)
8431         {
8432           /* Don't write &op0, etc., because that would prevent op0
8433              from being kept in a register.
8434              Instead, make copies of the our local variables and
8435              pass the copies by reference, then copy them back afterward.  */
8436           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8437           enum tree_code xresultcode = resultcode;
8438           tree val
8439             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8440
8441           if (val != 0)
8442             return val;
8443
8444           op0 = xop0, op1 = xop1;
8445           converted = 1;
8446           resultcode = xresultcode;
8447
8448           if (warn_sign_compare && skip_evaluation == 0)
8449             {
8450               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8451               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8452               int unsignedp0, unsignedp1;
8453               tree primop0 = get_narrower (op0, &unsignedp0);
8454               tree primop1 = get_narrower (op1, &unsignedp1);
8455
8456               xop0 = orig_op0;
8457               xop1 = orig_op1;
8458               STRIP_TYPE_NOPS (xop0);
8459               STRIP_TYPE_NOPS (xop1);
8460
8461               /* Give warnings for comparisons between signed and unsigned
8462                  quantities that may fail.
8463
8464                  Do the checking based on the original operand trees, so that
8465                  casts will be considered, but default promotions won't be.
8466
8467                  Do not warn if the comparison is being done in a signed type,
8468                  since the signed type will only be chosen if it can represent
8469                  all the values of the unsigned type.  */
8470               if (!TYPE_UNSIGNED (result_type))
8471                 /* OK */;
8472               /* Do not warn if both operands are the same signedness.  */
8473               else if (op0_signed == op1_signed)
8474                 /* OK */;
8475               else
8476                 {
8477                   tree sop, uop;
8478                   bool ovf;
8479
8480                   if (op0_signed)
8481                     sop = xop0, uop = xop1;
8482                   else
8483                     sop = xop1, uop = xop0;
8484
8485                   /* Do not warn if the signed quantity is an
8486                      unsuffixed integer literal (or some static
8487                      constant expression involving such literals or a
8488                      conditional expression involving such literals)
8489                      and it is non-negative.  */
8490                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8491                     /* OK */;
8492                   /* Do not warn if the comparison is an equality operation,
8493                      the unsigned quantity is an integral constant, and it
8494                      would fit in the result if the result were signed.  */
8495                   else if (TREE_CODE (uop) == INTEGER_CST
8496                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8497                            && int_fits_type_p
8498                            (uop, c_common_signed_type (result_type)))
8499                     /* OK */;
8500                   /* Do not warn if the unsigned quantity is an enumeration
8501                      constant and its maximum value would fit in the result
8502                      if the result were signed.  */
8503                   else if (TREE_CODE (uop) == INTEGER_CST
8504                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8505                            && int_fits_type_p
8506                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8507                             c_common_signed_type (result_type)))
8508                     /* OK */;
8509                   else
8510                     warning (OPT_Wsign_compare, "comparison between signed and unsigned");
8511                 }
8512
8513               /* Warn if two unsigned values are being compared in a size
8514                  larger than their original size, and one (and only one) is the
8515                  result of a `~' operator.  This comparison will always fail.
8516
8517                  Also warn if one operand is a constant, and the constant
8518                  does not have all bits set that are set in the ~ operand
8519                  when it is extended.  */
8520
8521               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8522                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8523                 {
8524                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8525                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8526                                             &unsignedp0);
8527                   else
8528                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8529                                             &unsignedp1);
8530
8531                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8532                     {
8533                       tree primop;
8534                       HOST_WIDE_INT constant, mask;
8535                       int unsignedp, bits;
8536
8537                       if (host_integerp (primop0, 0))
8538                         {
8539                           primop = primop1;
8540                           unsignedp = unsignedp1;
8541                           constant = tree_low_cst (primop0, 0);
8542                         }
8543                       else
8544                         {
8545                           primop = primop0;
8546                           unsignedp = unsignedp0;
8547                           constant = tree_low_cst (primop1, 0);
8548                         }
8549
8550                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8551                       if (bits < TYPE_PRECISION (result_type)
8552                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8553                         {
8554                           mask = (~(HOST_WIDE_INT) 0) << bits;
8555                           if ((mask & constant) != mask)
8556                             warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with constant");
8557                         }
8558                     }
8559                   else if (unsignedp0 && unsignedp1
8560                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8561                                < TYPE_PRECISION (result_type))
8562                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8563                                < TYPE_PRECISION (result_type)))
8564                     warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with unsigned");
8565                 }
8566             }
8567         }
8568     }
8569
8570   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8571      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8572      Then the expression will be built.
8573      It will be given type FINAL_TYPE if that is nonzero;
8574      otherwise, it will be given type RESULT_TYPE.  */
8575
8576   if (!result_type)
8577     {
8578       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8579       return error_mark_node;
8580     }
8581
8582   if (!converted)
8583     {
8584       if (TREE_TYPE (op0) != result_type)
8585         op0 = convert_and_check (result_type, op0);
8586       if (TREE_TYPE (op1) != result_type)
8587         op1 = convert_and_check (result_type, op1);
8588
8589       /* This can happen if one operand has a vector type, and the other
8590          has a different type.  */
8591       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8592         return error_mark_node;
8593     }
8594
8595   if (build_type == NULL_TREE)
8596     build_type = result_type;
8597
8598   {
8599     /* Treat expressions in initializers specially as they can't trap.  */
8600     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8601                                                                     build_type,
8602                                                                     op0, op1)
8603                                          : fold_build2 (resultcode, build_type,
8604                                                         op0, op1);
8605
8606     if (final_type != 0)
8607       result = convert (final_type, result);
8608     return result;
8609   }
8610 }
8611
8612
8613 /* Convert EXPR to be a truth-value, validating its type for this
8614    purpose.  */
8615
8616 tree
8617 c_objc_common_truthvalue_conversion (tree expr)
8618 {
8619   switch (TREE_CODE (TREE_TYPE (expr)))
8620     {
8621     case ARRAY_TYPE:
8622       error ("used array that cannot be converted to pointer where scalar is required");
8623       return error_mark_node;
8624
8625     case RECORD_TYPE:
8626       error ("used struct type value where scalar is required");
8627       return error_mark_node;
8628
8629     case UNION_TYPE:
8630       error ("used union type value where scalar is required");
8631       return error_mark_node;
8632
8633     case FUNCTION_TYPE:
8634       gcc_unreachable ();
8635
8636     default:
8637       break;
8638     }
8639
8640   /* ??? Should we also give an error for void and vectors rather than
8641      leaving those to give errors later?  */
8642   return c_common_truthvalue_conversion (expr);
8643 }
8644 \f
8645
8646 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8647    required.  */
8648
8649 tree
8650 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8651                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8652 {
8653   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8654     {
8655       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8656       /* Executing a compound literal inside a function reinitializes
8657          it.  */
8658       if (!TREE_STATIC (decl))
8659         *se = true;
8660       return decl;
8661     }
8662   else
8663     return expr;
8664 }
8665 \f
8666 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8667
8668 tree
8669 c_begin_omp_parallel (void)
8670 {
8671   tree block;
8672
8673   keep_next_level ();
8674   block = c_begin_compound_stmt (true);
8675
8676   return block;
8677 }
8678
8679 tree
8680 c_finish_omp_parallel (tree clauses, tree block)
8681 {
8682   tree stmt;
8683
8684   block = c_end_compound_stmt (block, true);
8685
8686   stmt = make_node (OMP_PARALLEL);
8687   TREE_TYPE (stmt) = void_type_node;
8688   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8689   OMP_PARALLEL_BODY (stmt) = block;
8690
8691   return add_stmt (stmt);
8692 }
8693
8694 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8695    Remove any elements from the list that are invalid.  */
8696
8697 tree
8698 c_finish_omp_clauses (tree clauses)
8699 {
8700   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8701   tree c, t, *pc = &clauses;
8702   const char *name;
8703
8704   bitmap_obstack_initialize (NULL);
8705   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8706   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8707   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8708
8709   for (pc = &clauses, c = clauses; c ; c = *pc)
8710     {
8711       bool remove = false;
8712       bool need_complete = false;
8713       bool need_implicitly_determined = false;
8714
8715       switch (OMP_CLAUSE_CODE (c))
8716         {
8717         case OMP_CLAUSE_SHARED:
8718           name = "shared";
8719           need_implicitly_determined = true;
8720           goto check_dup_generic;
8721
8722         case OMP_CLAUSE_PRIVATE:
8723           name = "private";
8724           need_complete = true;
8725           need_implicitly_determined = true;
8726           goto check_dup_generic;
8727
8728         case OMP_CLAUSE_REDUCTION:
8729           name = "reduction";
8730           need_implicitly_determined = true;
8731           t = OMP_CLAUSE_DECL (c);
8732           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8733               || POINTER_TYPE_P (TREE_TYPE (t)))
8734             {
8735               error ("%qE has invalid type for %<reduction%>", t);
8736               remove = true;
8737             }
8738           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8739             {
8740               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8741               const char *r_name = NULL;
8742
8743               switch (r_code)
8744                 {
8745                 case PLUS_EXPR:
8746                 case MULT_EXPR:
8747                 case MINUS_EXPR:
8748                   break;
8749                 case BIT_AND_EXPR:
8750                   r_name = "&";
8751                   break;
8752                 case BIT_XOR_EXPR:
8753                   r_name = "^";
8754                   break;
8755                 case BIT_IOR_EXPR:
8756                   r_name = "|";
8757                   break;
8758                 case TRUTH_ANDIF_EXPR:
8759                   r_name = "&&";
8760                   break;
8761                 case TRUTH_ORIF_EXPR:
8762                   r_name = "||";
8763                   break;
8764                 default:
8765                   gcc_unreachable ();
8766                 }
8767               if (r_name)
8768                 {
8769                   error ("%qE has invalid type for %<reduction(%s)%>",
8770                          t, r_name);
8771                   remove = true;
8772                 }
8773             }
8774           goto check_dup_generic;
8775
8776         case OMP_CLAUSE_COPYPRIVATE:
8777           name = "copyprivate";
8778           goto check_dup_generic;
8779
8780         case OMP_CLAUSE_COPYIN:
8781           name = "copyin";
8782           t = OMP_CLAUSE_DECL (c);
8783           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8784             {
8785               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8786               remove = true;
8787             }
8788           goto check_dup_generic;
8789
8790         check_dup_generic:
8791           t = OMP_CLAUSE_DECL (c);
8792           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8793             {
8794               error ("%qE is not a variable in clause %qs", t, name);
8795               remove = true;
8796             }
8797           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8798                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8799                    || bitmap_bit_p (&lastprivate_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 (&generic_head, DECL_UID (t));
8806           break;
8807
8808         case OMP_CLAUSE_FIRSTPRIVATE:
8809           name = "firstprivate";
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 %<firstprivate%>", t);
8816               remove = true;
8817             }
8818           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8819                    || bitmap_bit_p (&firstprivate_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 (&firstprivate_head, DECL_UID (t));
8826           break;
8827
8828         case OMP_CLAUSE_LASTPRIVATE:
8829           name = "lastprivate";
8830           t = OMP_CLAUSE_DECL (c);
8831           need_complete = true;
8832           need_implicitly_determined = true;
8833           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8834             {
8835               error ("%qE is not a variable in clause %<lastprivate%>", t);
8836               remove = true;
8837             }
8838           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8839                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8840             {
8841               error ("%qE appears more than once in data clauses", t);
8842               remove = true;
8843             }
8844           else
8845             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8846           break;
8847
8848         case OMP_CLAUSE_IF:
8849         case OMP_CLAUSE_NUM_THREADS:
8850         case OMP_CLAUSE_SCHEDULE:
8851         case OMP_CLAUSE_NOWAIT:
8852         case OMP_CLAUSE_ORDERED:
8853         case OMP_CLAUSE_DEFAULT:
8854           pc = &OMP_CLAUSE_CHAIN (c);
8855           continue;
8856
8857         default:
8858           gcc_unreachable ();
8859         }
8860
8861       if (!remove)
8862         {
8863           t = OMP_CLAUSE_DECL (c);
8864
8865           if (need_complete)
8866             {
8867               t = require_complete_type (t);
8868               if (t == error_mark_node)
8869                 remove = true;
8870             }
8871
8872           if (need_implicitly_determined)
8873             {
8874               const char *share_name = NULL;
8875
8876               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8877                 share_name = "threadprivate";
8878               else switch (c_omp_predetermined_sharing (t))
8879                 {
8880                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8881                   break;
8882                 case OMP_CLAUSE_DEFAULT_SHARED:
8883                   share_name = "shared";
8884                   break;
8885                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8886                   share_name = "private";
8887                   break;
8888                 default:
8889                   gcc_unreachable ();
8890                 }
8891               if (share_name)
8892                 {
8893                   error ("%qE is predetermined %qs for %qs",
8894                          t, share_name, name);
8895                   remove = true;
8896                 }
8897             }
8898         }
8899
8900       if (remove)
8901         *pc = OMP_CLAUSE_CHAIN (c);
8902       else
8903         pc = &OMP_CLAUSE_CHAIN (c);
8904     }
8905
8906   bitmap_obstack_release (NULL);
8907   return clauses;
8908 }
8909
8910 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8911    down to the element type of an array.  */
8912
8913 tree
8914 c_build_qualified_type (tree type, int type_quals)
8915 {
8916   if (type == error_mark_node)
8917     return type;
8918
8919   if (TREE_CODE (type) == ARRAY_TYPE)
8920     {
8921       tree t;
8922       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8923                                                   type_quals);
8924
8925       /* See if we already have an identically qualified type.  */
8926       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8927         {
8928           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8929               && TYPE_NAME (t) == TYPE_NAME (type)
8930               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8931               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8932                                        TYPE_ATTRIBUTES (type)))
8933             break;
8934         }
8935       if (!t)
8936         {
8937           tree domain = TYPE_DOMAIN (type);
8938
8939           t = build_variant_type_copy (type);
8940           TREE_TYPE (t) = element_type;
8941
8942           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8943               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8944             SET_TYPE_STRUCTURAL_EQUALITY (t);
8945           else if (TYPE_CANONICAL (element_type) != element_type
8946                    || (domain && TYPE_CANONICAL (domain) != domain))
8947             {
8948               tree unqualified_canon
8949                 = build_array_type (TYPE_CANONICAL (element_type),
8950                                     domain? TYPE_CANONICAL (domain)
8951                                           : NULL_TREE);
8952               TYPE_CANONICAL (t)
8953                 = c_build_qualified_type (unqualified_canon, type_quals);
8954             }
8955           else
8956             TYPE_CANONICAL (t) = t;
8957         }
8958       return t;
8959     }
8960
8961   /* A restrict-qualified pointer type must be a pointer to object or
8962      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8963      REFERENCE_TYPEs, which is appropriate for C++.  */
8964   if ((type_quals & TYPE_QUAL_RESTRICT)
8965       && (!POINTER_TYPE_P (type)
8966           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8967     {
8968       error ("invalid use of %<restrict%>");
8969       type_quals &= ~TYPE_QUAL_RESTRICT;
8970     }
8971
8972   return build_qualified_type (type, type_quals);
8973 }