gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   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 (int, 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                 || CONVERT_EXPR_P (exp.value))
1661                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1662           {
1663             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1664               not_lvalue = true;
1665             exp.value = TREE_OPERAND (exp.value, 0);
1666           }
1667
1668         if (TREE_NO_WARNING (orig_exp))
1669           TREE_NO_WARNING (exp.value) = 1;
1670
1671         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1672         if (!flag_isoc99 && !lvalue_array_p)
1673           {
1674             /* Before C99, non-lvalue arrays do not decay to pointers.
1675                Normally, using such an array would be invalid; but it can
1676                be used correctly inside sizeof or as a statement expression.
1677                Thus, do not give an error here; an error will result later.  */
1678             return exp;
1679           }
1680
1681         exp.value = array_to_pointer_conversion (exp.value);
1682       }
1683       break;
1684     case FUNCTION_TYPE:
1685       exp.value = function_to_pointer_conversion (exp.value);
1686       break;
1687     default:
1688       STRIP_TYPE_NOPS (exp.value);
1689       if (TREE_NO_WARNING (orig_exp))
1690         TREE_NO_WARNING (exp.value) = 1;
1691       break;
1692     }
1693
1694   return exp;
1695 }
1696
1697
1698 /* EXP is an expression of integer type.  Apply the integer promotions
1699    to it and return the promoted value.  */
1700
1701 tree
1702 perform_integral_promotions (tree exp)
1703 {
1704   tree type = TREE_TYPE (exp);
1705   enum tree_code code = TREE_CODE (type);
1706
1707   gcc_assert (INTEGRAL_TYPE_P (type));
1708
1709   /* Normally convert enums to int,
1710      but convert wide enums to something wider.  */
1711   if (code == ENUMERAL_TYPE)
1712     {
1713       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1714                                           TYPE_PRECISION (integer_type_node)),
1715                                      ((TYPE_PRECISION (type)
1716                                        >= TYPE_PRECISION (integer_type_node))
1717                                       && TYPE_UNSIGNED (type)));
1718
1719       return convert (type, exp);
1720     }
1721
1722   /* ??? This should no longer be needed now bit-fields have their
1723      proper types.  */
1724   if (TREE_CODE (exp) == COMPONENT_REF
1725       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1726       /* If it's thinner than an int, promote it like a
1727          c_promoting_integer_type_p, otherwise leave it alone.  */
1728       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1729                                TYPE_PRECISION (integer_type_node)))
1730     return convert (integer_type_node, exp);
1731
1732   if (c_promoting_integer_type_p (type))
1733     {
1734       /* Preserve unsignedness if not really getting any wider.  */
1735       if (TYPE_UNSIGNED (type)
1736           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1737         return convert (unsigned_type_node, exp);
1738
1739       return convert (integer_type_node, exp);
1740     }
1741
1742   return exp;
1743 }
1744
1745
1746 /* Perform default promotions for C data used in expressions.
1747    Enumeral types or short or char are converted to int.
1748    In addition, manifest constants symbols are replaced by their values.  */
1749
1750 tree
1751 default_conversion (tree exp)
1752 {
1753   tree orig_exp;
1754   tree type = TREE_TYPE (exp);
1755   enum tree_code code = TREE_CODE (type);
1756
1757   /* Functions and arrays have been converted during parsing.  */
1758   gcc_assert (code != FUNCTION_TYPE);
1759   if (code == ARRAY_TYPE)
1760     return exp;
1761
1762   /* Constants can be used directly unless they're not loadable.  */
1763   if (TREE_CODE (exp) == CONST_DECL)
1764     exp = DECL_INITIAL (exp);
1765
1766   /* Replace a nonvolatile const static variable with its value unless
1767      it is an array, in which case we must be sure that taking the
1768      address of the array produces consistent results.  */
1769   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1770     {
1771       exp = decl_constant_value_for_broken_optimization (exp);
1772       type = TREE_TYPE (exp);
1773     }
1774
1775   /* Strip no-op conversions.  */
1776   orig_exp = exp;
1777   STRIP_TYPE_NOPS (exp);
1778
1779   if (TREE_NO_WARNING (orig_exp))
1780     TREE_NO_WARNING (exp) = 1;
1781
1782   if (code == VOID_TYPE)
1783     {
1784       error ("void value not ignored as it ought to be");
1785       return error_mark_node;
1786     }
1787
1788   exp = require_complete_type (exp);
1789   if (exp == error_mark_node)
1790     return error_mark_node;
1791
1792   if (INTEGRAL_TYPE_P (type))
1793     return perform_integral_promotions (exp);
1794
1795   return exp;
1796 }
1797 \f
1798 /* Look up COMPONENT in a structure or union DECL.
1799
1800    If the component name is not found, returns NULL_TREE.  Otherwise,
1801    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1802    stepping down the chain to the component, which is in the last
1803    TREE_VALUE of the list.  Normally the list is of length one, but if
1804    the component is embedded within (nested) anonymous structures or
1805    unions, the list steps down the chain to the component.  */
1806
1807 static tree
1808 lookup_field (tree decl, tree component)
1809 {
1810   tree type = TREE_TYPE (decl);
1811   tree field;
1812
1813   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1814      to the field elements.  Use a binary search on this array to quickly
1815      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1816      will always be set for structures which have many elements.  */
1817
1818   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1819     {
1820       int bot, top, half;
1821       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1822
1823       field = TYPE_FIELDS (type);
1824       bot = 0;
1825       top = TYPE_LANG_SPECIFIC (type)->s->len;
1826       while (top - bot > 1)
1827         {
1828           half = (top - bot + 1) >> 1;
1829           field = field_array[bot+half];
1830
1831           if (DECL_NAME (field) == NULL_TREE)
1832             {
1833               /* Step through all anon unions in linear fashion.  */
1834               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1835                 {
1836                   field = field_array[bot++];
1837                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1838                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1839                     {
1840                       tree anon = lookup_field (field, component);
1841
1842                       if (anon)
1843                         return tree_cons (NULL_TREE, field, anon);
1844                     }
1845                 }
1846
1847               /* Entire record is only anon unions.  */
1848               if (bot > top)
1849                 return NULL_TREE;
1850
1851               /* Restart the binary search, with new lower bound.  */
1852               continue;
1853             }
1854
1855           if (DECL_NAME (field) == component)
1856             break;
1857           if (DECL_NAME (field) < component)
1858             bot += half;
1859           else
1860             top = bot + half;
1861         }
1862
1863       if (DECL_NAME (field_array[bot]) == component)
1864         field = field_array[bot];
1865       else if (DECL_NAME (field) != component)
1866         return NULL_TREE;
1867     }
1868   else
1869     {
1870       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1871         {
1872           if (DECL_NAME (field) == NULL_TREE
1873               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1874                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1875             {
1876               tree anon = lookup_field (field, component);
1877
1878               if (anon)
1879                 return tree_cons (NULL_TREE, field, anon);
1880             }
1881
1882           if (DECL_NAME (field) == component)
1883             break;
1884         }
1885
1886       if (field == NULL_TREE)
1887         return NULL_TREE;
1888     }
1889
1890   return tree_cons (NULL_TREE, field, NULL_TREE);
1891 }
1892
1893 /* Make an expression to refer to the COMPONENT field of
1894    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1895
1896 tree
1897 build_component_ref (tree datum, tree component)
1898 {
1899   tree type = TREE_TYPE (datum);
1900   enum tree_code code = TREE_CODE (type);
1901   tree field = NULL;
1902   tree ref;
1903
1904   if (!objc_is_public (datum, component))
1905     return error_mark_node;
1906
1907   /* See if there is a field or component with name COMPONENT.  */
1908
1909   if (code == RECORD_TYPE || code == UNION_TYPE)
1910     {
1911       if (!COMPLETE_TYPE_P (type))
1912         {
1913           c_incomplete_type_error (NULL_TREE, type);
1914           return error_mark_node;
1915         }
1916
1917       field = lookup_field (datum, component);
1918
1919       if (!field)
1920         {
1921           error ("%qT has no member named %qE", type, component);
1922           return error_mark_node;
1923         }
1924
1925       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1926          This might be better solved in future the way the C++ front
1927          end does it - by giving the anonymous entities each a
1928          separate name and type, and then have build_component_ref
1929          recursively call itself.  We can't do that here.  */
1930       do
1931         {
1932           tree subdatum = TREE_VALUE (field);
1933           int quals;
1934           tree subtype;
1935
1936           if (TREE_TYPE (subdatum) == error_mark_node)
1937             return error_mark_node;
1938
1939           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1940           quals |= TYPE_QUALS (TREE_TYPE (datum));
1941           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1942
1943           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1944                         NULL_TREE);
1945           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1946             TREE_READONLY (ref) = 1;
1947           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1948             TREE_THIS_VOLATILE (ref) = 1;
1949
1950           if (TREE_DEPRECATED (subdatum))
1951             warn_deprecated_use (subdatum);
1952
1953           datum = ref;
1954
1955           field = TREE_CHAIN (field);
1956         }
1957       while (field);
1958
1959       return ref;
1960     }
1961   else if (code != ERROR_MARK)
1962     error ("request for member %qE in something not a structure or union",
1963            component);
1964
1965   return error_mark_node;
1966 }
1967 \f
1968 /* Given an expression PTR for a pointer, return an expression
1969    for the value pointed to.
1970    ERRORSTRING is the name of the operator to appear in error messages.  */
1971
1972 tree
1973 build_indirect_ref (tree ptr, const char *errorstring)
1974 {
1975   tree pointer = default_conversion (ptr);
1976   tree type = TREE_TYPE (pointer);
1977
1978   if (TREE_CODE (type) == POINTER_TYPE)
1979     {
1980       if (CONVERT_EXPR_P (pointer)
1981           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1982         {
1983           /* If a warning is issued, mark it to avoid duplicates from
1984              the backend.  This only needs to be done at
1985              warn_strict_aliasing > 2.  */
1986           if (warn_strict_aliasing > 2)
1987             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1988                                          type, TREE_OPERAND (pointer, 0)))
1989               TREE_NO_WARNING (pointer) = 1;
1990         }
1991
1992       if (TREE_CODE (pointer) == ADDR_EXPR
1993           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1994               == TREE_TYPE (type)))
1995         return TREE_OPERAND (pointer, 0);
1996       else
1997         {
1998           tree t = TREE_TYPE (type);
1999           tree ref;
2000
2001           ref = build1 (INDIRECT_REF, t, pointer);
2002
2003           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2004             {
2005               error ("dereferencing pointer to incomplete type");
2006               return error_mark_node;
2007             }
2008           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2009             warning (0, "dereferencing %<void *%> pointer");
2010
2011           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2012              so that we get the proper error message if the result is used
2013              to assign to.  Also, &* is supposed to be a no-op.
2014              And ANSI C seems to specify that the type of the result
2015              should be the const type.  */
2016           /* A de-reference of a pointer to const is not a const.  It is valid
2017              to change it via some other pointer.  */
2018           TREE_READONLY (ref) = TYPE_READONLY (t);
2019           TREE_SIDE_EFFECTS (ref)
2020             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2021           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2022           return ref;
2023         }
2024     }
2025   else if (TREE_CODE (pointer) != ERROR_MARK)
2026     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2027   return error_mark_node;
2028 }
2029
2030 /* This handles expressions of the form "a[i]", which denotes
2031    an array reference.
2032
2033    This is logically equivalent in C to *(a+i), but we may do it differently.
2034    If A is a variable or a member, we generate a primitive ARRAY_REF.
2035    This avoids forcing the array out of registers, and can work on
2036    arrays that are not lvalues (for example, members of structures returned
2037    by functions).  */
2038
2039 tree
2040 build_array_ref (tree array, tree index)
2041 {
2042   bool swapped = false;
2043   if (TREE_TYPE (array) == error_mark_node
2044       || TREE_TYPE (index) == error_mark_node)
2045     return error_mark_node;
2046
2047   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2048       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2049     {
2050       tree temp;
2051       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2052           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2053         {
2054           error ("subscripted value is neither array nor pointer");
2055           return error_mark_node;
2056         }
2057       temp = array;
2058       array = index;
2059       index = temp;
2060       swapped = true;
2061     }
2062
2063   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2064     {
2065       error ("array subscript is not an integer");
2066       return error_mark_node;
2067     }
2068
2069   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2070     {
2071       error ("subscripted value is pointer to function");
2072       return error_mark_node;
2073     }
2074
2075   /* ??? Existing practice has been to warn only when the char
2076      index is syntactically the index, not for char[array].  */
2077   if (!swapped)
2078      warn_array_subscript_with_type_char (index);
2079
2080   /* Apply default promotions *after* noticing character types.  */
2081   index = default_conversion (index);
2082
2083   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2084
2085   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2086     {
2087       tree rval, type;
2088
2089       /* An array that is indexed by a non-constant
2090          cannot be stored in a register; we must be able to do
2091          address arithmetic on its address.
2092          Likewise an array of elements of variable size.  */
2093       if (TREE_CODE (index) != INTEGER_CST
2094           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2095               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2096         {
2097           if (!c_mark_addressable (array))
2098             return error_mark_node;
2099         }
2100       /* An array that is indexed by a constant value which is not within
2101          the array bounds cannot be stored in a register either; because we
2102          would get a crash in store_bit_field/extract_bit_field when trying
2103          to access a non-existent part of the register.  */
2104       if (TREE_CODE (index) == INTEGER_CST
2105           && TYPE_DOMAIN (TREE_TYPE (array))
2106           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2107         {
2108           if (!c_mark_addressable (array))
2109             return error_mark_node;
2110         }
2111
2112       if (pedantic)
2113         {
2114           tree foo = array;
2115           while (TREE_CODE (foo) == COMPONENT_REF)
2116             foo = TREE_OPERAND (foo, 0);
2117           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2118             pedwarn ("ISO C forbids subscripting %<register%> array");
2119           else if (!flag_isoc99 && !lvalue_p (foo))
2120             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2121         }
2122
2123       type = TREE_TYPE (TREE_TYPE (array));
2124       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2125       /* Array ref is const/volatile if the array elements are
2126          or if the array is.  */
2127       TREE_READONLY (rval)
2128         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2129             | TREE_READONLY (array));
2130       TREE_SIDE_EFFECTS (rval)
2131         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2132             | TREE_SIDE_EFFECTS (array));
2133       TREE_THIS_VOLATILE (rval)
2134         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2135             /* This was added by rms on 16 Nov 91.
2136                It fixes  vol struct foo *a;  a->elts[1]
2137                in an inline function.
2138                Hope it doesn't break something else.  */
2139             | TREE_THIS_VOLATILE (array));
2140       return require_complete_type (fold (rval));
2141     }
2142   else
2143     {
2144       tree ar = default_conversion (array);
2145
2146       if (ar == error_mark_node)
2147         return ar;
2148
2149       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2150       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2151
2152       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2153                                  "array indexing");
2154     }
2155 }
2156 \f
2157 /* Build an external reference to identifier ID.  FUN indicates
2158    whether this will be used for a function call.  LOC is the source
2159    location of the identifier.  */
2160 tree
2161 build_external_ref (tree id, int fun, location_t loc)
2162 {
2163   tree ref;
2164   tree decl = lookup_name (id);
2165
2166   /* In Objective-C, an instance variable (ivar) may be preferred to
2167      whatever lookup_name() found.  */
2168   decl = objc_lookup_ivar (decl, id);
2169
2170   if (decl && decl != error_mark_node)
2171     ref = decl;
2172   else if (fun)
2173     /* Implicit function declaration.  */
2174     ref = implicitly_declare (id);
2175   else if (decl == error_mark_node)
2176     /* Don't complain about something that's already been
2177        complained about.  */
2178     return error_mark_node;
2179   else
2180     {
2181       undeclared_variable (id, loc);
2182       return error_mark_node;
2183     }
2184
2185   if (TREE_TYPE (ref) == error_mark_node)
2186     return error_mark_node;
2187
2188   if (TREE_DEPRECATED (ref))
2189     warn_deprecated_use (ref);
2190
2191   /* Recursive call does not count as usage.  */
2192   if (ref != current_function_decl)
2193     {
2194       if (!skip_evaluation)
2195         assemble_external (ref);
2196       TREE_USED (ref) = 1;
2197     }
2198
2199   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2200     {
2201       if (!in_sizeof && !in_typeof)
2202         C_DECL_USED (ref) = 1;
2203       else if (DECL_INITIAL (ref) == 0
2204                && DECL_EXTERNAL (ref)
2205                && !TREE_PUBLIC (ref))
2206         record_maybe_used_decl (ref);
2207     }
2208
2209   if (TREE_CODE (ref) == CONST_DECL)
2210     {
2211       used_types_insert (TREE_TYPE (ref));
2212       ref = DECL_INITIAL (ref);
2213       TREE_CONSTANT (ref) = 1;
2214     }
2215   else if (current_function_decl != 0
2216            && !DECL_FILE_SCOPE_P (current_function_decl)
2217            && (TREE_CODE (ref) == VAR_DECL
2218                || TREE_CODE (ref) == PARM_DECL
2219                || TREE_CODE (ref) == FUNCTION_DECL))
2220     {
2221       tree context = decl_function_context (ref);
2222
2223       if (context != 0 && context != current_function_decl)
2224         DECL_NONLOCAL (ref) = 1;
2225     }
2226   /* C99 6.7.4p3: An inline definition of a function with external
2227      linkage ... shall not contain a reference to an identifier with
2228      internal linkage.  */
2229   else if (current_function_decl != 0
2230            && DECL_DECLARED_INLINE_P (current_function_decl)
2231            && DECL_EXTERNAL (current_function_decl)
2232            && VAR_OR_FUNCTION_DECL_P (ref)
2233            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2234            && ! TREE_PUBLIC (ref)
2235            && DECL_CONTEXT (ref) != current_function_decl)
2236     pedwarn ("%H%qD is static but used in inline function %qD "
2237              "which is not static", &loc, ref, current_function_decl);
2238
2239   return ref;
2240 }
2241
2242 /* Record details of decls possibly used inside sizeof or typeof.  */
2243 struct maybe_used_decl
2244 {
2245   /* The decl.  */
2246   tree decl;
2247   /* The level seen at (in_sizeof + in_typeof).  */
2248   int level;
2249   /* The next one at this level or above, or NULL.  */
2250   struct maybe_used_decl *next;
2251 };
2252
2253 static struct maybe_used_decl *maybe_used_decls;
2254
2255 /* Record that DECL, an undefined static function reference seen
2256    inside sizeof or typeof, might be used if the operand of sizeof is
2257    a VLA type or the operand of typeof is a variably modified
2258    type.  */
2259
2260 static void
2261 record_maybe_used_decl (tree decl)
2262 {
2263   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2264   t->decl = decl;
2265   t->level = in_sizeof + in_typeof;
2266   t->next = maybe_used_decls;
2267   maybe_used_decls = t;
2268 }
2269
2270 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2271    USED is false, just discard them.  If it is true, mark them used
2272    (if no longer inside sizeof or typeof) or move them to the next
2273    level up (if still inside sizeof or typeof).  */
2274
2275 void
2276 pop_maybe_used (bool used)
2277 {
2278   struct maybe_used_decl *p = maybe_used_decls;
2279   int cur_level = in_sizeof + in_typeof;
2280   while (p && p->level > cur_level)
2281     {
2282       if (used)
2283         {
2284           if (cur_level == 0)
2285             C_DECL_USED (p->decl) = 1;
2286           else
2287             p->level = cur_level;
2288         }
2289       p = p->next;
2290     }
2291   if (!used || cur_level == 0)
2292     maybe_used_decls = p;
2293 }
2294
2295 /* Return the result of sizeof applied to EXPR.  */
2296
2297 struct c_expr
2298 c_expr_sizeof_expr (struct c_expr expr)
2299 {
2300   struct c_expr ret;
2301   if (expr.value == error_mark_node)
2302     {
2303       ret.value = error_mark_node;
2304       ret.original_code = ERROR_MARK;
2305       pop_maybe_used (false);
2306     }
2307   else
2308     {
2309       ret.value = c_sizeof (TREE_TYPE (expr.value));
2310       ret.original_code = ERROR_MARK;
2311       if (c_vla_type_p (TREE_TYPE (expr.value)))
2312         {
2313           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2314           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2315         }
2316       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2317     }
2318   return ret;
2319 }
2320
2321 /* Return the result of sizeof applied to T, a structure for the type
2322    name passed to sizeof (rather than the type itself).  */
2323
2324 struct c_expr
2325 c_expr_sizeof_type (struct c_type_name *t)
2326 {
2327   tree type;
2328   struct c_expr ret;
2329   type = groktypename (t);
2330   ret.value = c_sizeof (type);
2331   ret.original_code = ERROR_MARK;
2332   pop_maybe_used (type != error_mark_node
2333                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2334   return ret;
2335 }
2336
2337 /* Build a function call to function FUNCTION with parameters PARAMS.
2338    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2339    TREE_VALUE of each node is a parameter-expression.
2340    FUNCTION's data type may be a function type or a pointer-to-function.  */
2341
2342 tree
2343 build_function_call (tree function, tree params)
2344 {
2345   tree fntype, fundecl = 0;
2346   tree name = NULL_TREE, result;
2347   tree tem;
2348   int nargs;
2349   tree *argarray;
2350
2351
2352   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2353   STRIP_TYPE_NOPS (function);
2354
2355   /* Convert anything with function type to a pointer-to-function.  */
2356   if (TREE_CODE (function) == FUNCTION_DECL)
2357     {
2358       /* Implement type-directed function overloading for builtins.
2359          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2360          handle all the type checking.  The result is a complete expression
2361          that implements this function call.  */
2362       tem = resolve_overloaded_builtin (function, params);
2363       if (tem)
2364         return tem;
2365
2366       name = DECL_NAME (function);
2367       fundecl = function;
2368     }
2369   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2370     function = function_to_pointer_conversion (function);
2371
2372   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2373      expressions, like those used for ObjC messenger dispatches.  */
2374   function = objc_rewrite_function_call (function, params);
2375
2376   fntype = TREE_TYPE (function);
2377
2378   if (TREE_CODE (fntype) == ERROR_MARK)
2379     return error_mark_node;
2380
2381   if (!(TREE_CODE (fntype) == POINTER_TYPE
2382         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2383     {
2384       error ("called object %qE is not a function", function);
2385       return error_mark_node;
2386     }
2387
2388   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2389     current_function_returns_abnormally = 1;
2390
2391   /* fntype now gets the type of function pointed to.  */
2392   fntype = TREE_TYPE (fntype);
2393
2394   /* Check that the function is called through a compatible prototype.
2395      If it is not, replace the call by a trap, wrapped up in a compound
2396      expression if necessary.  This has the nice side-effect to prevent
2397      the tree-inliner from generating invalid assignment trees which may
2398      blow up in the RTL expander later.  */
2399   if (CONVERT_EXPR_P (function)
2400       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2401       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2402       && !comptypes (fntype, TREE_TYPE (tem)))
2403     {
2404       tree return_type = TREE_TYPE (fntype);
2405       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2406                                        NULL_TREE);
2407
2408       /* This situation leads to run-time undefined behavior.  We can't,
2409          therefore, simply error unless we can prove that all possible
2410          executions of the program must execute the code.  */
2411       warning (0, "function called through a non-compatible type");
2412
2413       /* We can, however, treat "undefined" any way we please.
2414          Call abort to encourage the user to fix the program.  */
2415       inform ("if this code is reached, the program will abort");
2416
2417       if (VOID_TYPE_P (return_type))
2418         return trap;
2419       else
2420         {
2421           tree rhs;
2422
2423           if (AGGREGATE_TYPE_P (return_type))
2424             rhs = build_compound_literal (return_type,
2425                                           build_constructor (return_type, 0));
2426           else
2427             rhs = fold_convert (return_type, integer_zero_node);
2428
2429           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2430         }
2431     }
2432
2433   /* Convert the parameters to the types declared in the
2434      function prototype, or apply default promotions.  */
2435
2436   nargs = list_length (params);
2437   argarray = (tree *) alloca (nargs * sizeof (tree));
2438   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2439                              params, function, fundecl);
2440   if (nargs < 0)
2441     return error_mark_node;
2442
2443   /* Check that arguments to builtin functions match the expectations.  */
2444   if (fundecl
2445       && DECL_BUILT_IN (fundecl)
2446       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2447       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2448     return error_mark_node;
2449
2450   /* Check that the arguments to the function are valid.  */
2451   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2452                             TYPE_ARG_TYPES (fntype));
2453
2454   if (require_constant_value)
2455     {
2456       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2457                                                   function, nargs, argarray);
2458       if (TREE_CONSTANT (result)
2459           && (name == NULL_TREE
2460               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2461         pedwarn_init ("initializer element is not constant");
2462     }
2463   else
2464     result = fold_build_call_array (TREE_TYPE (fntype),
2465                                     function, nargs, argarray);
2466
2467   if (VOID_TYPE_P (TREE_TYPE (result)))
2468     return result;
2469   return require_complete_type (result);
2470 }
2471 \f
2472 /* Convert the argument expressions in the list VALUES
2473    to the types in the list TYPELIST.  The resulting arguments are
2474    stored in the array ARGARRAY which has size NARGS.
2475
2476    If TYPELIST is exhausted, or when an element has NULL as its type,
2477    perform the default conversions.
2478
2479    PARMLIST is the chain of parm decls for the function being called.
2480    It may be 0, if that info is not available.
2481    It is used only for generating error messages.
2482
2483    FUNCTION is a tree for the called function.  It is used only for
2484    error messages, where it is formatted with %qE.
2485
2486    This is also where warnings about wrong number of args are generated.
2487
2488    VALUES is a chain of TREE_LIST nodes with the elements of the list
2489    in the TREE_VALUE slots of those nodes.
2490
2491    Returns the actual number of arguments processed (which may be less
2492    than NARGS in some error situations), or -1 on failure.  */
2493
2494 static int
2495 convert_arguments (int nargs, tree *argarray,
2496                    tree typelist, tree values, tree function, tree fundecl)
2497 {
2498   tree typetail, valtail;
2499   int parmnum;
2500   const bool type_generic = fundecl
2501     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2502   tree selector;
2503
2504   /* Change pointer to function to the function itself for
2505      diagnostics.  */
2506   if (TREE_CODE (function) == ADDR_EXPR
2507       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2508     function = TREE_OPERAND (function, 0);
2509
2510   /* Handle an ObjC selector specially for diagnostics.  */
2511   selector = objc_message_selector ();
2512
2513   /* Scan the given expressions and types, producing individual
2514      converted arguments and storing them in ARGARRAY.  */
2515
2516   for (valtail = values, typetail = typelist, parmnum = 0;
2517        valtail;
2518        valtail = TREE_CHAIN (valtail), parmnum++)
2519     {
2520       tree type = typetail ? TREE_VALUE (typetail) : 0;
2521       tree val = TREE_VALUE (valtail);
2522       tree rname = function;
2523       int argnum = parmnum + 1;
2524       const char *invalid_func_diag;
2525
2526       if (type == void_type_node)
2527         {
2528           error ("too many arguments to function %qE", function);
2529           return parmnum;
2530         }
2531
2532       if (selector && argnum > 2)
2533         {
2534           rname = selector;
2535           argnum -= 2;
2536         }
2537
2538       STRIP_TYPE_NOPS (val);
2539
2540       val = require_complete_type (val);
2541
2542       if (type != 0)
2543         {
2544           /* Formal parm type is specified by a function prototype.  */
2545           tree parmval;
2546
2547           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2548             {
2549               error ("type of formal parameter %d is incomplete", parmnum + 1);
2550               parmval = val;
2551             }
2552           else
2553             {
2554               /* Optionally warn about conversions that
2555                  differ from the default conversions.  */
2556               if (warn_traditional_conversion || warn_traditional)
2557                 {
2558                   unsigned int formal_prec = TYPE_PRECISION (type);
2559
2560                   if (INTEGRAL_TYPE_P (type)
2561                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2562                     warning (0, "passing argument %d of %qE as integer "
2563                              "rather than floating due to prototype",
2564                              argnum, rname);
2565                   if (INTEGRAL_TYPE_P (type)
2566                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2567                     warning (0, "passing argument %d of %qE as integer "
2568                              "rather than complex due to prototype",
2569                              argnum, rname);
2570                   else if (TREE_CODE (type) == COMPLEX_TYPE
2571                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2572                     warning (0, "passing argument %d of %qE as complex "
2573                              "rather than floating due to prototype",
2574                              argnum, rname);
2575                   else if (TREE_CODE (type) == REAL_TYPE
2576                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2577                     warning (0, "passing argument %d of %qE as floating "
2578                              "rather than integer due to prototype",
2579                              argnum, rname);
2580                   else if (TREE_CODE (type) == COMPLEX_TYPE
2581                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2582                     warning (0, "passing argument %d of %qE as complex "
2583                              "rather than integer due to prototype",
2584                              argnum, rname);
2585                   else if (TREE_CODE (type) == REAL_TYPE
2586                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2587                     warning (0, "passing argument %d of %qE as floating "
2588                              "rather than complex due to prototype",
2589                              argnum, rname);
2590                   /* ??? At some point, messages should be written about
2591                      conversions between complex types, but that's too messy
2592                      to do now.  */
2593                   else if (TREE_CODE (type) == REAL_TYPE
2594                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2595                     {
2596                       /* Warn if any argument is passed as `float',
2597                          since without a prototype it would be `double'.  */
2598                       if (formal_prec == TYPE_PRECISION (float_type_node)
2599                           && type != dfloat32_type_node)
2600                         warning (0, "passing argument %d of %qE as %<float%> "
2601                                  "rather than %<double%> due to prototype",
2602                                  argnum, rname);
2603
2604                       /* Warn if mismatch between argument and prototype
2605                          for decimal float types.  Warn of conversions with
2606                          binary float types and of precision narrowing due to
2607                          prototype. */
2608                       else if (type != TREE_TYPE (val)
2609                                && (type == dfloat32_type_node
2610                                    || type == dfloat64_type_node
2611                                    || type == dfloat128_type_node
2612                                    || TREE_TYPE (val) == dfloat32_type_node
2613                                    || TREE_TYPE (val) == dfloat64_type_node
2614                                    || TREE_TYPE (val) == dfloat128_type_node)
2615                                && (formal_prec
2616                                    <= TYPE_PRECISION (TREE_TYPE (val))
2617                                    || (type == dfloat128_type_node
2618                                        && (TREE_TYPE (val)
2619                                            != dfloat64_type_node
2620                                            && (TREE_TYPE (val)
2621                                                != dfloat32_type_node)))
2622                                    || (type == dfloat64_type_node
2623                                        && (TREE_TYPE (val)
2624                                            != dfloat32_type_node))))
2625                         warning (0, "passing argument %d of %qE as %qT "
2626                                  "rather than %qT due to prototype",
2627                                  argnum, rname, type, TREE_TYPE (val));
2628
2629                     }
2630                   /* Detect integer changing in width or signedness.
2631                      These warnings are only activated with
2632                      -Wtraditional-conversion, not with -Wtraditional.  */
2633                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2634                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2635                     {
2636                       tree would_have_been = default_conversion (val);
2637                       tree type1 = TREE_TYPE (would_have_been);
2638
2639                       if (TREE_CODE (type) == ENUMERAL_TYPE
2640                           && (TYPE_MAIN_VARIANT (type)
2641                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2642                         /* No warning if function asks for enum
2643                            and the actual arg is that enum type.  */
2644                         ;
2645                       else if (formal_prec != TYPE_PRECISION (type1))
2646                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2647                                  "with different width due to prototype",
2648                                  argnum, rname);
2649                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2650                         ;
2651                       /* Don't complain if the formal parameter type
2652                          is an enum, because we can't tell now whether
2653                          the value was an enum--even the same enum.  */
2654                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2655                         ;
2656                       else if (TREE_CODE (val) == INTEGER_CST
2657                                && int_fits_type_p (val, type))
2658                         /* Change in signedness doesn't matter
2659                            if a constant value is unaffected.  */
2660                         ;
2661                       /* If the value is extended from a narrower
2662                          unsigned type, it doesn't matter whether we
2663                          pass it as signed or unsigned; the value
2664                          certainly is the same either way.  */
2665                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2666                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2667                         ;
2668                       else if (TYPE_UNSIGNED (type))
2669                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2670                                  "as unsigned due to prototype",
2671                                  argnum, rname);
2672                       else
2673                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2674                                  "as signed due to prototype", argnum, rname);
2675                     }
2676                 }
2677
2678               parmval = convert_for_assignment (type, val, ic_argpass,
2679                                                 fundecl, function,
2680                                                 parmnum + 1);
2681
2682               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2683                   && INTEGRAL_TYPE_P (type)
2684                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2685                 parmval = default_conversion (parmval);
2686             }
2687           argarray[parmnum] = parmval;
2688         }
2689       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2690                && (TYPE_PRECISION (TREE_TYPE (val))
2691                    < TYPE_PRECISION (double_type_node))
2692                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2693         {
2694           if (type_generic)
2695             argarray[parmnum] = val;
2696           else
2697             /* Convert `float' to `double'.  */
2698             argarray[parmnum] = convert (double_type_node, val);
2699         }
2700       else if ((invalid_func_diag =
2701                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2702         {
2703           error (invalid_func_diag);
2704           return -1;
2705         }
2706       else
2707         /* Convert `short' and `char' to full-size `int'.  */
2708         argarray[parmnum] = default_conversion (val);
2709
2710       if (typetail)
2711         typetail = TREE_CHAIN (typetail);
2712     }
2713
2714   gcc_assert (parmnum == nargs);
2715
2716   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2717     {
2718       error ("too few arguments to function %qE", function);
2719       return -1;
2720     }
2721
2722   return parmnum;
2723 }
2724 \f
2725 /* This is the entry point used by the parser to build unary operators
2726    in the input.  CODE, a tree_code, specifies the unary operator, and
2727    ARG is the operand.  For unary plus, the C parser currently uses
2728    CONVERT_EXPR for code.  */
2729
2730 struct c_expr
2731 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2732 {
2733   struct c_expr result;
2734
2735   result.original_code = ERROR_MARK;
2736   result.value = build_unary_op (code, arg.value, 0);
2737
2738   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2739     overflow_warning (result.value);
2740
2741   return result;
2742 }
2743
2744 /* This is the entry point used by the parser to build binary operators
2745    in the input.  CODE, a tree_code, specifies the binary operator, and
2746    ARG1 and ARG2 are the operands.  In addition to constructing the
2747    expression, we check for operands that were written with other binary
2748    operators in a way that is likely to confuse the user.  */
2749
2750 struct c_expr
2751 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2752                         struct c_expr arg2)
2753 {
2754   struct c_expr result;
2755
2756   enum tree_code code1 = arg1.original_code;
2757   enum tree_code code2 = arg2.original_code;
2758
2759   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2760   result.original_code = code;
2761
2762   if (TREE_CODE (result.value) == ERROR_MARK)
2763     return result;
2764
2765   /* Check for cases such as x+y<<z which users are likely
2766      to misinterpret.  */
2767   if (warn_parentheses)
2768     warn_about_parentheses (code, code1, code2);
2769
2770   if (code1 != tcc_comparison)
2771     warn_logical_operator (code, arg1.value, arg2.value);
2772
2773   /* Warn about comparisons against string literals, with the exception
2774      of testing for equality or inequality of a string literal with NULL.  */
2775   if (code == EQ_EXPR || code == NE_EXPR)
2776     {
2777       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2778           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2779         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2780     }
2781   else if (TREE_CODE_CLASS (code) == tcc_comparison
2782            && (code1 == STRING_CST || code2 == STRING_CST))
2783     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2784
2785   if (TREE_OVERFLOW_P (result.value)
2786       && !TREE_OVERFLOW_P (arg1.value)
2787       && !TREE_OVERFLOW_P (arg2.value))
2788     overflow_warning (result.value);
2789
2790   return result;
2791 }
2792 \f
2793 /* Return a tree for the difference of pointers OP0 and OP1.
2794    The resulting tree has type int.  */
2795
2796 static tree
2797 pointer_diff (tree op0, tree op1)
2798 {
2799   tree restype = ptrdiff_type_node;
2800
2801   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2802   tree con0, con1, lit0, lit1;
2803   tree orig_op1 = op1;
2804
2805   if (pedantic || warn_pointer_arith)
2806     {
2807       if (TREE_CODE (target_type) == VOID_TYPE)
2808         pedwarn ("pointer of type %<void *%> used in subtraction");
2809       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2810         pedwarn ("pointer to a function used in subtraction");
2811     }
2812
2813   /* If the conversion to ptrdiff_type does anything like widening or
2814      converting a partial to an integral mode, we get a convert_expression
2815      that is in the way to do any simplifications.
2816      (fold-const.c doesn't know that the extra bits won't be needed.
2817      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2818      different mode in place.)
2819      So first try to find a common term here 'by hand'; we want to cover
2820      at least the cases that occur in legal static initializers.  */
2821   if (CONVERT_EXPR_P (op0)
2822       && (TYPE_PRECISION (TREE_TYPE (op0))
2823           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2824     con0 = TREE_OPERAND (op0, 0);
2825   else
2826     con0 = op0;
2827   if (CONVERT_EXPR_P (op1)
2828       && (TYPE_PRECISION (TREE_TYPE (op1))
2829           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2830     con1 = TREE_OPERAND (op1, 0);
2831   else
2832     con1 = op1;
2833
2834   if (TREE_CODE (con0) == PLUS_EXPR)
2835     {
2836       lit0 = TREE_OPERAND (con0, 1);
2837       con0 = TREE_OPERAND (con0, 0);
2838     }
2839   else
2840     lit0 = integer_zero_node;
2841
2842   if (TREE_CODE (con1) == PLUS_EXPR)
2843     {
2844       lit1 = TREE_OPERAND (con1, 1);
2845       con1 = TREE_OPERAND (con1, 0);
2846     }
2847   else
2848     lit1 = integer_zero_node;
2849
2850   if (operand_equal_p (con0, con1, 0))
2851     {
2852       op0 = lit0;
2853       op1 = lit1;
2854     }
2855
2856
2857   /* First do the subtraction as integers;
2858      then drop through to build the divide operator.
2859      Do not do default conversions on the minus operator
2860      in case restype is a short type.  */
2861
2862   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2863                          convert (restype, op1), 0);
2864   /* This generates an error if op1 is pointer to incomplete type.  */
2865   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2866     error ("arithmetic on pointer to an incomplete type");
2867
2868   /* This generates an error if op0 is pointer to incomplete type.  */
2869   op1 = c_size_in_bytes (target_type);
2870
2871   /* Divide by the size, in easiest possible way.  */
2872   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2873 }
2874 \f
2875 /* Construct and perhaps optimize a tree representation
2876    for a unary operation.  CODE, a tree_code, specifies the operation
2877    and XARG is the operand.
2878    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2879    the default promotions (such as from short to int).
2880    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2881    allows non-lvalues; this is only used to handle conversion of non-lvalue
2882    arrays to pointers in C99.  */
2883
2884 tree
2885 build_unary_op (enum tree_code code, tree xarg, int flag)
2886 {
2887   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2888   tree arg = xarg;
2889   tree argtype = 0;
2890   enum tree_code typecode;
2891   tree val;
2892   int noconvert = flag;
2893   const char *invalid_op_diag;
2894
2895   if (code != ADDR_EXPR)
2896     arg = require_complete_type (arg);
2897
2898   typecode = TREE_CODE (TREE_TYPE (arg));
2899   if (typecode == ERROR_MARK)
2900     return error_mark_node;
2901   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2902     typecode = INTEGER_TYPE;
2903
2904   if ((invalid_op_diag
2905        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2906     {
2907       error (invalid_op_diag);
2908       return error_mark_node;
2909     }
2910
2911   switch (code)
2912     {
2913     case CONVERT_EXPR:
2914       /* This is used for unary plus, because a CONVERT_EXPR
2915          is enough to prevent anybody from looking inside for
2916          associativity, but won't generate any code.  */
2917       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2918             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2919             || typecode == VECTOR_TYPE))
2920         {
2921           error ("wrong type argument to unary plus");
2922           return error_mark_node;
2923         }
2924       else if (!noconvert)
2925         arg = default_conversion (arg);
2926       arg = non_lvalue (arg);
2927       break;
2928
2929     case NEGATE_EXPR:
2930       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2931             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2932             || typecode == VECTOR_TYPE))
2933         {
2934           error ("wrong type argument to unary minus");
2935           return error_mark_node;
2936         }
2937       else if (!noconvert)
2938         arg = default_conversion (arg);
2939       break;
2940
2941     case BIT_NOT_EXPR:
2942       /* ~ works on integer types and non float vectors. */
2943       if (typecode == INTEGER_TYPE
2944           || (typecode == VECTOR_TYPE
2945               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2946         {
2947           if (!noconvert)
2948             arg = default_conversion (arg);
2949         }
2950       else if (typecode == COMPLEX_TYPE)
2951         {
2952           code = CONJ_EXPR;
2953           if (pedantic)
2954             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2955           if (!noconvert)
2956             arg = default_conversion (arg);
2957         }
2958       else
2959         {
2960           error ("wrong type argument to bit-complement");
2961           return error_mark_node;
2962         }
2963       break;
2964
2965     case ABS_EXPR:
2966       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2967         {
2968           error ("wrong type argument to abs");
2969           return error_mark_node;
2970         }
2971       else if (!noconvert)
2972         arg = default_conversion (arg);
2973       break;
2974
2975     case CONJ_EXPR:
2976       /* Conjugating a real value is a no-op, but allow it anyway.  */
2977       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2978             || typecode == COMPLEX_TYPE))
2979         {
2980           error ("wrong type argument to conjugation");
2981           return error_mark_node;
2982         }
2983       else if (!noconvert)
2984         arg = default_conversion (arg);
2985       break;
2986
2987     case TRUTH_NOT_EXPR:
2988       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
2989           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2990           && typecode != COMPLEX_TYPE)
2991         {
2992           error ("wrong type argument to unary exclamation mark");
2993           return error_mark_node;
2994         }
2995       arg = c_objc_common_truthvalue_conversion (arg);
2996       return invert_truthvalue (arg);
2997
2998     case REALPART_EXPR:
2999       if (TREE_CODE (arg) == COMPLEX_CST)
3000         return TREE_REALPART (arg);
3001       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3002         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3003       else
3004         return arg;
3005
3006     case IMAGPART_EXPR:
3007       if (TREE_CODE (arg) == COMPLEX_CST)
3008         return TREE_IMAGPART (arg);
3009       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3010         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3011       else
3012         return convert (TREE_TYPE (arg), integer_zero_node);
3013
3014     case PREINCREMENT_EXPR:
3015     case POSTINCREMENT_EXPR:
3016     case PREDECREMENT_EXPR:
3017     case POSTDECREMENT_EXPR:
3018
3019       /* Increment or decrement the real part of the value,
3020          and don't change the imaginary part.  */
3021       if (typecode == COMPLEX_TYPE)
3022         {
3023           tree real, imag;
3024
3025           if (pedantic)
3026             pedwarn ("ISO C does not support %<++%> and %<--%>"
3027                      " on complex types");
3028
3029           arg = stabilize_reference (arg);
3030           real = build_unary_op (REALPART_EXPR, arg, 1);
3031           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3032           real = build_unary_op (code, real, 1);
3033           if (real == error_mark_node || imag == error_mark_node)
3034             return error_mark_node;
3035           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3036                          real, imag);
3037         }
3038
3039       /* Report invalid types.  */
3040
3041       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3042           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3043         {
3044           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3045             error ("wrong type argument to increment");
3046           else
3047             error ("wrong type argument to decrement");
3048
3049           return error_mark_node;
3050         }
3051
3052       {
3053         tree inc;
3054         tree result_type = TREE_TYPE (arg);
3055
3056         arg = get_unwidened (arg, 0);
3057         argtype = TREE_TYPE (arg);
3058
3059         /* Compute the increment.  */
3060
3061         if (typecode == POINTER_TYPE)
3062           {
3063             /* If pointer target is an undefined struct,
3064                we just cannot know how to do the arithmetic.  */
3065             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3066               {
3067                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3068                   error ("increment of pointer to unknown structure");
3069                 else
3070                   error ("decrement of pointer to unknown structure");
3071               }
3072             else if ((pedantic || warn_pointer_arith)
3073                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3074                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
3075               {
3076                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3077                   pedwarn ("wrong type argument to increment");
3078                 else
3079                   pedwarn ("wrong type argument to decrement");
3080               }
3081
3082             inc = c_size_in_bytes (TREE_TYPE (result_type));
3083             inc = fold_convert (sizetype, inc);
3084           }
3085         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3086           {
3087             /* For signed fract types, we invert ++ to -- or
3088                -- to ++, and change inc from 1 to -1, because
3089                it is not possible to represent 1 in signed fract constants.
3090                For unsigned fract types, the result always overflows and
3091                we get an undefined (original) or the maximum value.  */
3092             if (code == PREINCREMENT_EXPR)
3093               code = PREDECREMENT_EXPR;
3094             else if (code == PREDECREMENT_EXPR)
3095               code = PREINCREMENT_EXPR;
3096             else if (code == POSTINCREMENT_EXPR)
3097               code = POSTDECREMENT_EXPR;
3098             else /* code == POSTDECREMENT_EXPR  */
3099               code = POSTINCREMENT_EXPR;
3100
3101             inc = integer_minus_one_node;
3102             inc = convert (argtype, inc);
3103           }
3104         else
3105           {
3106             inc = integer_one_node;
3107             inc = convert (argtype, inc);
3108           }
3109
3110         /* Complain about anything else that is not a true lvalue.  */
3111         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3112                                     || code == POSTINCREMENT_EXPR)
3113                                    ? lv_increment
3114                                    : lv_decrement)))
3115           return error_mark_node;
3116
3117         /* Report a read-only lvalue.  */
3118         if (TREE_READONLY (arg))
3119           {
3120             readonly_error (arg,
3121                             ((code == PREINCREMENT_EXPR
3122                               || code == POSTINCREMENT_EXPR)
3123                              ? lv_increment : lv_decrement));
3124             return error_mark_node;
3125           }
3126
3127         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3128           val = boolean_increment (code, arg);
3129         else
3130           val = build2 (code, TREE_TYPE (arg), arg, inc);
3131         TREE_SIDE_EFFECTS (val) = 1;
3132         val = convert (result_type, val);
3133         if (TREE_CODE (val) != code)
3134           TREE_NO_WARNING (val) = 1;
3135         return val;
3136       }
3137
3138     case ADDR_EXPR:
3139       /* Note that this operation never does default_conversion.  */
3140
3141       /* Let &* cancel out to simplify resulting code.  */
3142       if (TREE_CODE (arg) == INDIRECT_REF)
3143         {
3144           /* Don't let this be an lvalue.  */
3145           if (lvalue_p (TREE_OPERAND (arg, 0)))
3146             return non_lvalue (TREE_OPERAND (arg, 0));
3147           return TREE_OPERAND (arg, 0);
3148         }
3149
3150       /* For &x[y], return x+y */
3151       if (TREE_CODE (arg) == ARRAY_REF)
3152         {
3153           tree op0 = TREE_OPERAND (arg, 0);
3154           if (!c_mark_addressable (op0))
3155             return error_mark_node;
3156           return build_binary_op (PLUS_EXPR,
3157                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3158                                    ? array_to_pointer_conversion (op0)
3159                                    : op0),
3160                                   TREE_OPERAND (arg, 1), 1);
3161         }
3162
3163       /* Anything not already handled and not a true memory reference
3164          or a non-lvalue array is an error.  */
3165       else if (typecode != FUNCTION_TYPE && !flag
3166                && !lvalue_or_else (arg, lv_addressof))
3167         return error_mark_node;
3168
3169       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3170       argtype = TREE_TYPE (arg);
3171
3172       /* If the lvalue is const or volatile, merge that into the type
3173          to which the address will point.  Note that you can't get a
3174          restricted pointer by taking the address of something, so we
3175          only have to deal with `const' and `volatile' here.  */
3176       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3177           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3178           argtype = c_build_type_variant (argtype,
3179                                           TREE_READONLY (arg),
3180                                           TREE_THIS_VOLATILE (arg));
3181
3182       if (!c_mark_addressable (arg))
3183         return error_mark_node;
3184
3185       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3186                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3187
3188       argtype = build_pointer_type (argtype);
3189
3190       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3191          when we have proper support for integer constant expressions.  */
3192       val = get_base_address (arg);
3193       if (val && TREE_CODE (val) == INDIRECT_REF
3194           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3195         {
3196           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3197
3198           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3199           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3200         }
3201
3202       val = build1 (ADDR_EXPR, argtype, arg);
3203
3204       return val;
3205
3206     default:
3207       gcc_unreachable ();
3208     }
3209
3210   if (argtype == 0)
3211     argtype = TREE_TYPE (arg);
3212   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3213                                 : fold_build1 (code, argtype, arg);
3214 }
3215
3216 /* Return nonzero if REF is an lvalue valid for this language.
3217    Lvalues can be assigned, unless their type has TYPE_READONLY.
3218    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3219
3220 static int
3221 lvalue_p (const_tree ref)
3222 {
3223   const enum tree_code code = TREE_CODE (ref);
3224
3225   switch (code)
3226     {
3227     case REALPART_EXPR:
3228     case IMAGPART_EXPR:
3229     case COMPONENT_REF:
3230       return lvalue_p (TREE_OPERAND (ref, 0));
3231
3232     case COMPOUND_LITERAL_EXPR:
3233     case STRING_CST:
3234       return 1;
3235
3236     case INDIRECT_REF:
3237     case ARRAY_REF:
3238     case VAR_DECL:
3239     case PARM_DECL:
3240     case RESULT_DECL:
3241     case ERROR_MARK:
3242       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3243               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3244
3245     case BIND_EXPR:
3246       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3247
3248     default:
3249       return 0;
3250     }
3251 }
3252 \f
3253 /* Give an error for storing in something that is 'const'.  */
3254
3255 static void
3256 readonly_error (tree arg, enum lvalue_use use)
3257 {
3258   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3259               || use == lv_asm);
3260   /* Using this macro rather than (for example) arrays of messages
3261      ensures that all the format strings are checked at compile
3262      time.  */
3263 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3264                                    : (use == lv_increment ? (I)         \
3265                                    : (use == lv_decrement ? (D) : (AS))))
3266   if (TREE_CODE (arg) == COMPONENT_REF)
3267     {
3268       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3269         readonly_error (TREE_OPERAND (arg, 0), use);
3270       else
3271         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3272                              G_("increment of read-only member %qD"),
3273                              G_("decrement of read-only member %qD"),
3274                              G_("read-only member %qD used as %<asm%> output")),
3275                TREE_OPERAND (arg, 1));
3276     }
3277   else if (TREE_CODE (arg) == VAR_DECL)
3278     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3279                          G_("increment of read-only variable %qD"),
3280                          G_("decrement of read-only variable %qD"),
3281                          G_("read-only variable %qD used as %<asm%> output")),
3282            arg);
3283   else
3284     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3285                          G_("increment of read-only location %qE"),
3286                          G_("decrement of read-only location %qE"),
3287                          G_("read-only location %qE used as %<asm%> output")),
3288            arg);
3289 }
3290
3291
3292 /* Return nonzero if REF is an lvalue valid for this language;
3293    otherwise, print an error message and return zero.  USE says
3294    how the lvalue is being used and so selects the error message.  */
3295
3296 static int
3297 lvalue_or_else (const_tree ref, enum lvalue_use use)
3298 {
3299   int win = lvalue_p (ref);
3300
3301   if (!win)
3302     lvalue_error (use);
3303
3304   return win;
3305 }
3306 \f
3307 /* Mark EXP saying that we need to be able to take the
3308    address of it; it should not be allocated in a register.
3309    Returns true if successful.  */
3310
3311 bool
3312 c_mark_addressable (tree exp)
3313 {
3314   tree x = exp;
3315
3316   while (1)
3317     switch (TREE_CODE (x))
3318       {
3319       case COMPONENT_REF:
3320         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3321           {
3322             error
3323               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3324             return false;
3325           }
3326
3327         /* ... fall through ...  */
3328
3329       case ADDR_EXPR:
3330       case ARRAY_REF:
3331       case REALPART_EXPR:
3332       case IMAGPART_EXPR:
3333         x = TREE_OPERAND (x, 0);
3334         break;
3335
3336       case COMPOUND_LITERAL_EXPR:
3337       case CONSTRUCTOR:
3338         TREE_ADDRESSABLE (x) = 1;
3339         return true;
3340
3341       case VAR_DECL:
3342       case CONST_DECL:
3343       case PARM_DECL:
3344       case RESULT_DECL:
3345         if (C_DECL_REGISTER (x)
3346             && DECL_NONLOCAL (x))
3347           {
3348             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3349               {
3350                 error
3351                   ("global register variable %qD used in nested function", x);
3352                 return false;
3353               }
3354             pedwarn ("register variable %qD used in nested function", x);
3355           }
3356         else if (C_DECL_REGISTER (x))
3357           {
3358             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3359               error ("address of global register variable %qD requested", x);
3360             else
3361               error ("address of register variable %qD requested", x);
3362             return false;
3363           }
3364
3365         /* drops in */
3366       case FUNCTION_DECL:
3367         TREE_ADDRESSABLE (x) = 1;
3368         /* drops out */
3369       default:
3370         return true;
3371     }
3372 }
3373 \f
3374 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3375
3376 tree
3377 build_conditional_expr (tree ifexp, tree op1, tree op2)
3378 {
3379   tree type1;
3380   tree type2;
3381   enum tree_code code1;
3382   enum tree_code code2;
3383   tree result_type = NULL;
3384   tree orig_op1 = op1, orig_op2 = op2;
3385
3386   /* Promote both alternatives.  */
3387
3388   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3389     op1 = default_conversion (op1);
3390   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3391     op2 = default_conversion (op2);
3392
3393   if (TREE_CODE (ifexp) == ERROR_MARK
3394       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3395       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3396     return error_mark_node;
3397
3398   type1 = TREE_TYPE (op1);
3399   code1 = TREE_CODE (type1);
3400   type2 = TREE_TYPE (op2);
3401   code2 = TREE_CODE (type2);
3402
3403   /* C90 does not permit non-lvalue arrays in conditional expressions.
3404      In C99 they will be pointers by now.  */
3405   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3406     {
3407       error ("non-lvalue array in conditional expression");
3408       return error_mark_node;
3409     }
3410
3411   /* Quickly detect the usual case where op1 and op2 have the same type
3412      after promotion.  */
3413   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3414     {
3415       if (type1 == type2)
3416         result_type = type1;
3417       else
3418         result_type = TYPE_MAIN_VARIANT (type1);
3419     }
3420   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3421             || code1 == COMPLEX_TYPE)
3422            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3423                || code2 == COMPLEX_TYPE))
3424     {
3425       result_type = c_common_type (type1, type2);
3426
3427       /* If -Wsign-compare, warn here if type1 and type2 have
3428          different signedness.  We'll promote the signed to unsigned
3429          and later code won't know it used to be different.
3430          Do this check on the original types, so that explicit casts
3431          will be considered, but default promotions won't.  */
3432       if (warn_sign_compare && !skip_evaluation)
3433         {
3434           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3435           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3436
3437           if (unsigned_op1 ^ unsigned_op2)
3438             {
3439               bool ovf;
3440
3441               /* Do not warn if the result type is signed, since the
3442                  signed type will only be chosen if it can represent
3443                  all the values of the unsigned type.  */
3444               if (!TYPE_UNSIGNED (result_type))
3445                 /* OK */;
3446               /* Do not warn if the signed quantity is an unsuffixed
3447                  integer literal (or some static constant expression
3448                  involving such literals) and it is non-negative.  */
3449               else if ((unsigned_op2
3450                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3451                        || (unsigned_op1
3452                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3453                 /* OK */;
3454               else
3455                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3456             }
3457         }
3458     }
3459   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3460     {
3461       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3462         pedwarn ("ISO C forbids conditional expr with only one void side");
3463       result_type = void_type_node;
3464     }
3465   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3466     {
3467       if (comp_target_types (type1, type2))
3468         result_type = common_pointer_type (type1, type2);
3469       else if (null_pointer_constant_p (orig_op1))
3470         result_type = qualify_type (type2, type1);
3471       else if (null_pointer_constant_p (orig_op2))
3472         result_type = qualify_type (type1, type2);
3473       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3474         {
3475           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3476             pedwarn ("ISO C forbids conditional expr between "
3477                      "%<void *%> and function pointer");
3478           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3479                                                           TREE_TYPE (type2)));
3480         }
3481       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3482         {
3483           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3484             pedwarn ("ISO C forbids conditional expr between "
3485                      "%<void *%> and function pointer");
3486           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3487                                                           TREE_TYPE (type1)));
3488         }
3489       else
3490         {
3491           pedwarn ("pointer type mismatch in conditional expression");
3492           result_type = build_pointer_type (void_type_node);
3493         }
3494     }
3495   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3496     {
3497       if (!null_pointer_constant_p (orig_op2))
3498         pedwarn ("pointer/integer type mismatch in conditional expression");
3499       else
3500         {
3501           op2 = null_pointer_node;
3502         }
3503       result_type = type1;
3504     }
3505   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3506     {
3507       if (!null_pointer_constant_p (orig_op1))
3508         pedwarn ("pointer/integer type mismatch in conditional expression");
3509       else
3510         {
3511           op1 = null_pointer_node;
3512         }
3513       result_type = type2;
3514     }
3515
3516   if (!result_type)
3517     {
3518       if (flag_cond_mismatch)
3519         result_type = void_type_node;
3520       else
3521         {
3522           error ("type mismatch in conditional expression");
3523           return error_mark_node;
3524         }
3525     }
3526
3527   /* Merge const and volatile flags of the incoming types.  */
3528   result_type
3529     = build_type_variant (result_type,
3530                           TREE_READONLY (op1) || TREE_READONLY (op2),
3531                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3532
3533   if (result_type != TREE_TYPE (op1))
3534     op1 = convert_and_check (result_type, op1);
3535   if (result_type != TREE_TYPE (op2))
3536     op2 = convert_and_check (result_type, op2);
3537
3538   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3539 }
3540 \f
3541 /* Return a compound expression that performs two expressions and
3542    returns the value of the second of them.  */
3543
3544 tree
3545 build_compound_expr (tree expr1, tree expr2)
3546 {
3547   if (!TREE_SIDE_EFFECTS (expr1))
3548     {
3549       /* The left-hand operand of a comma expression is like an expression
3550          statement: with -Wunused, we should warn if it doesn't have
3551          any side-effects, unless it was explicitly cast to (void).  */
3552       if (warn_unused_value)
3553         {
3554           if (VOID_TYPE_P (TREE_TYPE (expr1))
3555               && CONVERT_EXPR_P (expr1))
3556             ; /* (void) a, b */
3557           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3558                    && TREE_CODE (expr1) == COMPOUND_EXPR
3559                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3560             ; /* (void) a, (void) b, c */
3561           else
3562             warning (OPT_Wunused_value,
3563                      "left-hand operand of comma expression has no effect");
3564         }
3565     }
3566
3567   /* With -Wunused, we should also warn if the left-hand operand does have
3568      side-effects, but computes a value which is not used.  For example, in
3569      `foo() + bar(), baz()' the result of the `+' operator is not used,
3570      so we should issue a warning.  */
3571   else if (warn_unused_value)
3572     warn_if_unused_value (expr1, input_location);
3573
3574   if (expr2 == error_mark_node)
3575     return error_mark_node;
3576
3577   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3578 }
3579
3580 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3581
3582 tree
3583 build_c_cast (tree type, tree expr)
3584 {
3585   tree value = expr;
3586
3587   if (type == error_mark_node || expr == error_mark_node)
3588     return error_mark_node;
3589
3590   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3591      only in <protocol> qualifications.  But when constructing cast expressions,
3592      the protocols do matter and must be kept around.  */
3593   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3594     return build1 (NOP_EXPR, type, expr);
3595
3596   type = TYPE_MAIN_VARIANT (type);
3597
3598   if (TREE_CODE (type) == ARRAY_TYPE)
3599     {
3600       error ("cast specifies array type");
3601       return error_mark_node;
3602     }
3603
3604   if (TREE_CODE (type) == FUNCTION_TYPE)
3605     {
3606       error ("cast specifies function type");
3607       return error_mark_node;
3608     }
3609
3610   if (!VOID_TYPE_P (type))
3611     {
3612       value = require_complete_type (value);
3613       if (value == error_mark_node)
3614         return error_mark_node;
3615     }
3616
3617   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3618     {
3619       if (pedantic)
3620         {
3621           if (TREE_CODE (type) == RECORD_TYPE
3622               || TREE_CODE (type) == UNION_TYPE)
3623             pedwarn ("ISO C forbids casting nonscalar to the same type");
3624         }
3625     }
3626   else if (TREE_CODE (type) == UNION_TYPE)
3627     {
3628       tree field;
3629
3630       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3631         if (TREE_TYPE (field) != error_mark_node
3632             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3633                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3634           break;
3635
3636       if (field)
3637         {
3638           tree t;
3639
3640           if (pedantic)
3641             pedwarn ("ISO C forbids casts to union type");
3642           t = digest_init (type,
3643                            build_constructor_single (type, field, value),
3644                            true, 0);
3645           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3646           return t;
3647         }
3648       error ("cast to union type from type not present in union");
3649       return error_mark_node;
3650     }
3651   else
3652     {
3653       tree otype, ovalue;
3654
3655       if (type == void_type_node)
3656         return build1 (CONVERT_EXPR, type, value);
3657
3658       otype = TREE_TYPE (value);
3659
3660       /* Optionally warn about potentially worrisome casts.  */
3661
3662       if (warn_cast_qual
3663           && TREE_CODE (type) == POINTER_TYPE
3664           && TREE_CODE (otype) == POINTER_TYPE)
3665         {
3666           tree in_type = type;
3667           tree in_otype = otype;
3668           int added = 0;
3669           int discarded = 0;
3670
3671           /* Check that the qualifiers on IN_TYPE are a superset of
3672              the qualifiers of IN_OTYPE.  The outermost level of
3673              POINTER_TYPE nodes is uninteresting and we stop as soon
3674              as we hit a non-POINTER_TYPE node on either type.  */
3675           do
3676             {
3677               in_otype = TREE_TYPE (in_otype);
3678               in_type = TREE_TYPE (in_type);
3679
3680               /* GNU C allows cv-qualified function types.  'const'
3681                  means the function is very pure, 'volatile' means it
3682                  can't return.  We need to warn when such qualifiers
3683                  are added, not when they're taken away.  */
3684               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3685                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3686                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3687               else
3688                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3689             }
3690           while (TREE_CODE (in_type) == POINTER_TYPE
3691                  && TREE_CODE (in_otype) == POINTER_TYPE);
3692
3693           if (added)
3694             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3695
3696           if (discarded)
3697             /* There are qualifiers present in IN_OTYPE that are not
3698                present in IN_TYPE.  */
3699             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3700         }
3701
3702       /* Warn about possible alignment problems.  */
3703       if (STRICT_ALIGNMENT
3704           && TREE_CODE (type) == POINTER_TYPE
3705           && TREE_CODE (otype) == POINTER_TYPE
3706           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3707           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3708           /* Don't warn about opaque types, where the actual alignment
3709              restriction is unknown.  */
3710           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3711                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3712                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3713           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3714         warning (OPT_Wcast_align,
3715                  "cast increases required alignment of target type");
3716
3717       if (TREE_CODE (type) == INTEGER_TYPE
3718           && TREE_CODE (otype) == POINTER_TYPE
3719           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3720       /* Unlike conversion of integers to pointers, where the
3721          warning is disabled for converting constants because
3722          of cases such as SIG_*, warn about converting constant
3723          pointers to integers. In some cases it may cause unwanted
3724          sign extension, and a warning is appropriate.  */
3725         warning (OPT_Wpointer_to_int_cast,
3726                  "cast from pointer to integer of different size");
3727
3728       if (TREE_CODE (value) == CALL_EXPR
3729           && TREE_CODE (type) != TREE_CODE (otype))
3730         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3731                  "to non-matching type %qT", otype, type);
3732
3733       if (TREE_CODE (type) == POINTER_TYPE
3734           && TREE_CODE (otype) == INTEGER_TYPE
3735           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3736           /* Don't warn about converting any constant.  */
3737           && !TREE_CONSTANT (value))
3738         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3739                  "of different size");
3740
3741       if (warn_strict_aliasing <= 2)
3742         strict_aliasing_warning (otype, type, expr);
3743
3744       /* If pedantic, warn for conversions between function and object
3745          pointer types, except for converting a null pointer constant
3746          to function pointer type.  */
3747       if (pedantic
3748           && TREE_CODE (type) == POINTER_TYPE
3749           && TREE_CODE (otype) == POINTER_TYPE
3750           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3751           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3752         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3753
3754       if (pedantic
3755           && TREE_CODE (type) == POINTER_TYPE
3756           && TREE_CODE (otype) == POINTER_TYPE
3757           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3758           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3759           && !null_pointer_constant_p (value))
3760         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3761
3762       ovalue = value;
3763       value = convert (type, value);
3764
3765       /* Ignore any integer overflow caused by the cast.  */
3766       if (TREE_CODE (value) == INTEGER_CST)
3767         {
3768           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3769             {
3770               if (!TREE_OVERFLOW (value))
3771                 {
3772                   /* Avoid clobbering a shared constant.  */
3773                   value = copy_node (value);
3774                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3775                 }
3776             }
3777           else if (TREE_OVERFLOW (value))
3778             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3779             value = build_int_cst_wide (TREE_TYPE (value),
3780                                         TREE_INT_CST_LOW (value),
3781                                         TREE_INT_CST_HIGH (value));
3782         }
3783     }
3784
3785   /* Don't let a cast be an lvalue.  */
3786   if (value == expr)
3787     value = non_lvalue (value);
3788
3789   return value;
3790 }
3791
3792 /* Interpret a cast of expression EXPR to type TYPE.  */
3793 tree
3794 c_cast_expr (struct c_type_name *type_name, tree expr)
3795 {
3796   tree type;
3797   int saved_wsp = warn_strict_prototypes;
3798
3799   /* This avoids warnings about unprototyped casts on
3800      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3801   if (TREE_CODE (expr) == INTEGER_CST)
3802     warn_strict_prototypes = 0;
3803   type = groktypename (type_name);
3804   warn_strict_prototypes = saved_wsp;
3805
3806   return build_c_cast (type, expr);
3807 }
3808 \f
3809 /* Build an assignment expression of lvalue LHS from value RHS.
3810    MODIFYCODE is the code for a binary operator that we use
3811    to combine the old value of LHS with RHS to get the new value.
3812    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3813
3814 tree
3815 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3816 {
3817   tree result;
3818   tree newrhs;
3819   tree lhstype = TREE_TYPE (lhs);
3820   tree olhstype = lhstype;
3821
3822   /* Types that aren't fully specified cannot be used in assignments.  */
3823   lhs = require_complete_type (lhs);
3824
3825   /* Avoid duplicate error messages from operands that had errors.  */
3826   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3827     return error_mark_node;
3828
3829   if (!lvalue_or_else (lhs, lv_assign))
3830     return error_mark_node;
3831
3832   STRIP_TYPE_NOPS (rhs);
3833
3834   newrhs = rhs;
3835
3836   /* If a binary op has been requested, combine the old LHS value with the RHS
3837      producing the value we should actually store into the LHS.  */
3838
3839   if (modifycode != NOP_EXPR)
3840     {
3841       lhs = stabilize_reference (lhs);
3842       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3843     }
3844
3845   /* Give an error for storing in something that is 'const'.  */
3846
3847   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3848       || ((TREE_CODE (lhstype) == RECORD_TYPE
3849            || TREE_CODE (lhstype) == UNION_TYPE)
3850           && C_TYPE_FIELDS_READONLY (lhstype)))
3851     {
3852       readonly_error (lhs, lv_assign);
3853       return error_mark_node;
3854     }
3855
3856   /* If storing into a structure or union member,
3857      it has probably been given type `int'.
3858      Compute the type that would go with
3859      the actual amount of storage the member occupies.  */
3860
3861   if (TREE_CODE (lhs) == COMPONENT_REF
3862       && (TREE_CODE (lhstype) == INTEGER_TYPE
3863           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3864           || TREE_CODE (lhstype) == REAL_TYPE
3865           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3866     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3867
3868   /* If storing in a field that is in actuality a short or narrower than one,
3869      we must store in the field in its actual type.  */
3870
3871   if (lhstype != TREE_TYPE (lhs))
3872     {
3873       lhs = copy_node (lhs);
3874       TREE_TYPE (lhs) = lhstype;
3875     }
3876
3877   /* Convert new value to destination type.  */
3878
3879   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3880                                    NULL_TREE, NULL_TREE, 0);
3881   if (TREE_CODE (newrhs) == ERROR_MARK)
3882     return error_mark_node;
3883
3884   /* Emit ObjC write barrier, if necessary.  */
3885   if (c_dialect_objc () && flag_objc_gc)
3886     {
3887       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3888       if (result)
3889         return result;
3890     }
3891
3892   /* Scan operands.  */
3893
3894   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3895   TREE_SIDE_EFFECTS (result) = 1;
3896
3897   /* If we got the LHS in a different type for storing in,
3898      convert the result back to the nominal type of LHS
3899      so that the value we return always has the same type
3900      as the LHS argument.  */
3901
3902   if (olhstype == TREE_TYPE (result))
3903     return result;
3904   return convert_for_assignment (olhstype, result, ic_assign,
3905                                  NULL_TREE, NULL_TREE, 0);
3906 }
3907 \f
3908 /* Convert value RHS to type TYPE as preparation for an assignment
3909    to an lvalue of type TYPE.
3910    The real work of conversion is done by `convert'.
3911    The purpose of this function is to generate error messages
3912    for assignments that are not allowed in C.
3913    ERRTYPE says whether it is argument passing, assignment,
3914    initialization or return.
3915
3916    FUNCTION is a tree for the function being called.
3917    PARMNUM is the number of the argument, for printing in error messages.  */
3918
3919 static tree
3920 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3921                         tree fundecl, tree function, int parmnum)
3922 {
3923   enum tree_code codel = TREE_CODE (type);
3924   tree rhstype;
3925   enum tree_code coder;
3926   tree rname = NULL_TREE;
3927   bool objc_ok = false;
3928
3929   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3930     {
3931       tree selector;
3932       /* Change pointer to function to the function itself for
3933          diagnostics.  */
3934       if (TREE_CODE (function) == ADDR_EXPR
3935           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3936         function = TREE_OPERAND (function, 0);
3937
3938       /* Handle an ObjC selector specially for diagnostics.  */
3939       selector = objc_message_selector ();
3940       rname = function;
3941       if (selector && parmnum > 2)
3942         {
3943           rname = selector;
3944           parmnum -= 2;
3945         }
3946     }
3947
3948   /* This macro is used to emit diagnostics to ensure that all format
3949      strings are complete sentences, visible to gettext and checked at
3950      compile time.  */
3951 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3952   do {                                          \
3953     switch (errtype)                            \
3954       {                                         \
3955       case ic_argpass:                          \
3956         pedwarn (AR, parmnum, rname);           \
3957         break;                                  \
3958       case ic_argpass_nonproto:                 \
3959         warning (0, AR, parmnum, rname);                \
3960         break;                                  \
3961       case ic_assign:                           \
3962         pedwarn (AS);                           \
3963         break;                                  \
3964       case ic_init:                             \
3965         pedwarn (IN);                           \
3966         break;                                  \
3967       case ic_return:                           \
3968         pedwarn (RE);                           \
3969         break;                                  \
3970       default:                                  \
3971         gcc_unreachable ();                     \
3972       }                                         \
3973   } while (0)
3974
3975   STRIP_TYPE_NOPS (rhs);
3976
3977   if (optimize && TREE_CODE (rhs) == VAR_DECL
3978            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3979     rhs = decl_constant_value_for_broken_optimization (rhs);
3980
3981   rhstype = TREE_TYPE (rhs);
3982   coder = TREE_CODE (rhstype);
3983
3984   if (coder == ERROR_MARK)
3985     return error_mark_node;
3986
3987   if (c_dialect_objc ())
3988     {
3989       int parmno;
3990
3991       switch (errtype)
3992         {
3993         case ic_return:
3994           parmno = 0;
3995           break;
3996
3997         case ic_assign:
3998           parmno = -1;
3999           break;
4000
4001         case ic_init:
4002           parmno = -2;
4003           break;
4004
4005         default:
4006           parmno = parmnum;
4007           break;
4008         }
4009
4010       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4011     }
4012
4013   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4014     return rhs;
4015
4016   if (coder == VOID_TYPE)
4017     {
4018       /* Except for passing an argument to an unprototyped function,
4019          this is a constraint violation.  When passing an argument to
4020          an unprototyped function, it is compile-time undefined;
4021          making it a constraint in that case was rejected in
4022          DR#252.  */
4023       error ("void value not ignored as it ought to be");
4024       return error_mark_node;
4025     }
4026   rhs = require_complete_type (rhs);
4027   if (rhs == error_mark_node)
4028     return error_mark_node;
4029   /* A type converts to a reference to it.
4030      This code doesn't fully support references, it's just for the
4031      special case of va_start and va_copy.  */
4032   if (codel == REFERENCE_TYPE
4033       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4034     {
4035       if (!lvalue_p (rhs))
4036         {
4037           error ("cannot pass rvalue to reference parameter");
4038           return error_mark_node;
4039         }
4040       if (!c_mark_addressable (rhs))
4041         return error_mark_node;
4042       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4043
4044       /* We already know that these two types are compatible, but they
4045          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4046          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4047          likely to be va_list, a typedef to __builtin_va_list, which
4048          is different enough that it will cause problems later.  */
4049       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4050         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4051
4052       rhs = build1 (NOP_EXPR, type, rhs);
4053       return rhs;
4054     }
4055   /* Some types can interconvert without explicit casts.  */
4056   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4057            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4058     return convert (type, rhs);
4059   /* Arithmetic types all interconvert, and enum is treated like int.  */
4060   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4061             || codel == FIXED_POINT_TYPE
4062             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4063             || codel == BOOLEAN_TYPE)
4064            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4065                || coder == FIXED_POINT_TYPE
4066                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4067                || coder == BOOLEAN_TYPE))
4068     return convert_and_check (type, rhs);
4069
4070   /* Aggregates in different TUs might need conversion.  */
4071   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4072       && codel == coder
4073       && comptypes (type, rhstype))
4074     return convert_and_check (type, rhs);
4075
4076   /* Conversion to a transparent union from its member types.
4077      This applies only to function arguments.  */
4078   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4079       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4080     {
4081       tree memb, marginal_memb = NULL_TREE;
4082
4083       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4084         {
4085           tree memb_type = TREE_TYPE (memb);
4086
4087           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4088                          TYPE_MAIN_VARIANT (rhstype)))
4089             break;
4090
4091           if (TREE_CODE (memb_type) != POINTER_TYPE)
4092             continue;
4093
4094           if (coder == POINTER_TYPE)
4095             {
4096               tree ttl = TREE_TYPE (memb_type);
4097               tree ttr = TREE_TYPE (rhstype);
4098
4099               /* Any non-function converts to a [const][volatile] void *
4100                  and vice versa; otherwise, targets must be the same.
4101                  Meanwhile, the lhs target must have all the qualifiers of
4102                  the rhs.  */
4103               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4104                   || comp_target_types (memb_type, rhstype))
4105                 {
4106                   /* If this type won't generate any warnings, use it.  */
4107                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4108                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4109                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4110                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4111                              == TYPE_QUALS (ttr))
4112                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4113                              == TYPE_QUALS (ttl))))
4114                     break;
4115
4116                   /* Keep looking for a better type, but remember this one.  */
4117                   if (!marginal_memb)
4118                     marginal_memb = memb;
4119                 }
4120             }
4121
4122           /* Can convert integer zero to any pointer type.  */
4123           if (null_pointer_constant_p (rhs))
4124             {
4125               rhs = null_pointer_node;
4126               break;
4127             }
4128         }
4129
4130       if (memb || marginal_memb)
4131         {
4132           if (!memb)
4133             {
4134               /* We have only a marginally acceptable member type;
4135                  it needs a warning.  */
4136               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4137               tree ttr = TREE_TYPE (rhstype);
4138
4139               /* Const and volatile mean something different for function
4140                  types, so the usual warnings are not appropriate.  */
4141               if (TREE_CODE (ttr) == FUNCTION_TYPE
4142                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4143                 {
4144                   /* Because const and volatile on functions are
4145                      restrictions that say the function will not do
4146                      certain things, it is okay to use a const or volatile
4147                      function where an ordinary one is wanted, but not
4148                      vice-versa.  */
4149                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4150                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4151                                             "makes qualified function "
4152                                             "pointer from unqualified"),
4153                                          G_("assignment makes qualified "
4154                                             "function pointer from "
4155                                             "unqualified"),
4156                                          G_("initialization makes qualified "
4157                                             "function pointer from "
4158                                             "unqualified"),
4159                                          G_("return makes qualified function "
4160                                             "pointer from unqualified"));
4161                 }
4162               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4163                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4164                                         "qualifiers from pointer target type"),
4165                                      G_("assignment discards qualifiers "
4166                                         "from pointer target type"),
4167                                      G_("initialization discards qualifiers "
4168                                         "from pointer target type"),
4169                                      G_("return discards qualifiers from "
4170                                         "pointer target type"));
4171
4172               memb = marginal_memb;
4173             }
4174
4175           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4176             pedwarn ("ISO C prohibits argument conversion to union type");
4177
4178           rhs = fold_convert (TREE_TYPE (memb), rhs);
4179           return build_constructor_single (type, memb, rhs);
4180         }
4181     }
4182
4183   /* Conversions among pointers */
4184   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4185            && (coder == codel))
4186     {
4187       tree ttl = TREE_TYPE (type);
4188       tree ttr = TREE_TYPE (rhstype);
4189       tree mvl = ttl;
4190       tree mvr = ttr;
4191       bool is_opaque_pointer;
4192       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4193
4194       if (TREE_CODE (mvl) != ARRAY_TYPE)
4195         mvl = TYPE_MAIN_VARIANT (mvl);
4196       if (TREE_CODE (mvr) != ARRAY_TYPE)
4197         mvr = TYPE_MAIN_VARIANT (mvr);
4198       /* Opaque pointers are treated like void pointers.  */
4199       is_opaque_pointer = (targetm.vector_opaque_p (type)
4200                            || targetm.vector_opaque_p (rhstype))
4201         && TREE_CODE (ttl) == VECTOR_TYPE
4202         && TREE_CODE (ttr) == VECTOR_TYPE;
4203
4204       /* C++ does not allow the implicit conversion void* -> T*.  However,
4205          for the purpose of reducing the number of false positives, we
4206          tolerate the special case of
4207
4208                 int *p = NULL;
4209
4210          where NULL is typically defined in C to be '(void *) 0'.  */
4211       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4212         warning (OPT_Wc___compat, "request for implicit conversion from "
4213                  "%qT to %qT not permitted in C++", rhstype, type);
4214
4215       /* Check if the right-hand side has a format attribute but the
4216          left-hand side doesn't.  */
4217       if (warn_missing_format_attribute
4218           && check_missing_format_attribute (type, rhstype))
4219         {
4220           switch (errtype)
4221           {
4222           case ic_argpass:
4223           case ic_argpass_nonproto:
4224             warning (OPT_Wmissing_format_attribute,
4225                      "argument %d of %qE might be "
4226                      "a candidate for a format attribute",
4227                      parmnum, rname);
4228             break;
4229           case ic_assign:
4230             warning (OPT_Wmissing_format_attribute,
4231                      "assignment left-hand side might be "
4232                      "a candidate for a format attribute");
4233             break;
4234           case ic_init:
4235             warning (OPT_Wmissing_format_attribute,
4236                      "initialization left-hand side might be "
4237                      "a candidate for a format attribute");
4238             break;
4239           case ic_return:
4240             warning (OPT_Wmissing_format_attribute,
4241                      "return type might be "
4242                      "a candidate for a format attribute");
4243             break;
4244           default:
4245             gcc_unreachable ();
4246           }
4247         }
4248
4249       /* Any non-function converts to a [const][volatile] void *
4250          and vice versa; otherwise, targets must be the same.
4251          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4252       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4253           || (target_cmp = comp_target_types (type, rhstype))
4254           || is_opaque_pointer
4255           || (c_common_unsigned_type (mvl)
4256               == c_common_unsigned_type (mvr)))
4257         {
4258           if (pedantic
4259               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4260                   ||
4261                   (VOID_TYPE_P (ttr)
4262                    && !null_pointer_constant_p (rhs)
4263                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4264             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4265                                     "%qE between function pointer "
4266                                     "and %<void *%>"),
4267                                  G_("ISO C forbids assignment between "
4268                                     "function pointer and %<void *%>"),
4269                                  G_("ISO C forbids initialization between "
4270                                     "function pointer and %<void *%>"),
4271                                  G_("ISO C forbids return between function "
4272                                     "pointer and %<void *%>"));
4273           /* Const and volatile mean something different for function types,
4274              so the usual warnings are not appropriate.  */
4275           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4276                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4277             {
4278               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4279                 {
4280                   /* Types differing only by the presence of the 'volatile'
4281                      qualifier are acceptable if the 'volatile' has been added
4282                      in by the Objective-C EH machinery.  */
4283                   if (!objc_type_quals_match (ttl, ttr))
4284                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4285                                             "qualifiers from pointer target type"),
4286                                          G_("assignment discards qualifiers "
4287                                             "from pointer target type"),
4288                                          G_("initialization discards qualifiers "
4289                                             "from pointer target type"),
4290                                          G_("return discards qualifiers from "
4291                                             "pointer target type"));
4292                 }
4293               /* If this is not a case of ignoring a mismatch in signedness,
4294                  no warning.  */
4295               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4296                        || target_cmp)
4297                 ;
4298               /* If there is a mismatch, do warn.  */
4299               else if (warn_pointer_sign)
4300                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4301                                         "%d of %qE differ in signedness"),
4302                                      G_("pointer targets in assignment "
4303                                         "differ in signedness"),
4304                                      G_("pointer targets in initialization "
4305                                         "differ in signedness"),
4306                                      G_("pointer targets in return differ "
4307                                         "in signedness"));
4308             }
4309           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4310                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4311             {
4312               /* Because const and volatile on functions are restrictions
4313                  that say the function will not do certain things,
4314                  it is okay to use a const or volatile function
4315                  where an ordinary one is wanted, but not vice-versa.  */
4316               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4317                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4318                                         "qualified function pointer "
4319                                         "from unqualified"),
4320                                      G_("assignment makes qualified function "
4321                                         "pointer from unqualified"),
4322                                      G_("initialization makes qualified "
4323                                         "function pointer from unqualified"),
4324                                      G_("return makes qualified function "
4325                                         "pointer from unqualified"));
4326             }
4327         }
4328       else
4329         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4330         if (!objc_ok)
4331           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4332                                   "incompatible pointer type"),
4333                                G_("assignment from incompatible pointer type"),
4334                                G_("initialization from incompatible "
4335                                   "pointer type"),
4336                                G_("return from incompatible pointer type"));
4337
4338       return convert (type, rhs);
4339     }
4340   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4341     {
4342       /* ??? This should not be an error when inlining calls to
4343          unprototyped functions.  */
4344       error ("invalid use of non-lvalue array");
4345       return error_mark_node;
4346     }
4347   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4348     {
4349       /* An explicit constant 0 can convert to a pointer,
4350          or one that results from arithmetic, even including
4351          a cast to integer type.  */
4352       if (!null_pointer_constant_p (rhs))
4353         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4354                                 "pointer from integer without a cast"),
4355                              G_("assignment makes pointer from integer "
4356                                 "without a cast"),
4357                              G_("initialization makes pointer from "
4358                                 "integer without a cast"),
4359                              G_("return makes pointer from integer "
4360                                 "without a cast"));
4361
4362       return convert (type, rhs);
4363     }
4364   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4365     {
4366       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4367                               "from pointer without a cast"),
4368                            G_("assignment makes integer from pointer "
4369                               "without a cast"),
4370                            G_("initialization makes integer from pointer "
4371                               "without a cast"),
4372                            G_("return makes integer from pointer "
4373                               "without a cast"));
4374       return convert (type, rhs);
4375     }
4376   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4377     return convert (type, rhs);
4378
4379   switch (errtype)
4380     {
4381     case ic_argpass:
4382     case ic_argpass_nonproto:
4383       /* ??? This should not be an error when inlining calls to
4384          unprototyped functions.  */
4385       error ("incompatible type for argument %d of %qE", parmnum, rname);
4386       break;
4387     case ic_assign:
4388       error ("incompatible types in assignment");
4389       break;
4390     case ic_init:
4391       error ("incompatible types in initialization");
4392       break;
4393     case ic_return:
4394       error ("incompatible types in return");
4395       break;
4396     default:
4397       gcc_unreachable ();
4398     }
4399
4400   return error_mark_node;
4401 }
4402 \f
4403 /* If VALUE is a compound expr all of whose expressions are constant, then
4404    return its value.  Otherwise, return error_mark_node.
4405
4406    This is for handling COMPOUND_EXPRs as initializer elements
4407    which is allowed with a warning when -pedantic is specified.  */
4408
4409 static tree
4410 valid_compound_expr_initializer (tree value, tree endtype)
4411 {
4412   if (TREE_CODE (value) == COMPOUND_EXPR)
4413     {
4414       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4415           == error_mark_node)
4416         return error_mark_node;
4417       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4418                                               endtype);
4419     }
4420   else if (!initializer_constant_valid_p (value, endtype))
4421     return error_mark_node;
4422   else
4423     return value;
4424 }
4425 \f
4426 /* Perform appropriate conversions on the initial value of a variable,
4427    store it in the declaration DECL,
4428    and print any error messages that are appropriate.
4429    If the init is invalid, store an ERROR_MARK.  */
4430
4431 void
4432 store_init_value (tree decl, tree init)
4433 {
4434   tree value, type;
4435
4436   /* If variable's type was invalidly declared, just ignore it.  */
4437
4438   type = TREE_TYPE (decl);
4439   if (TREE_CODE (type) == ERROR_MARK)
4440     return;
4441
4442   /* Digest the specified initializer into an expression.  */
4443
4444   value = digest_init (type, init, true, TREE_STATIC (decl));
4445
4446   /* Store the expression if valid; else report error.  */
4447
4448   if (!in_system_header
4449       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4450     warning (OPT_Wtraditional, "traditional C rejects automatic "
4451              "aggregate initialization");
4452
4453   DECL_INITIAL (decl) = value;
4454
4455   /* ANSI wants warnings about out-of-range constant initializers.  */
4456   STRIP_TYPE_NOPS (value);
4457   if (TREE_STATIC (decl))
4458     constant_expression_warning (value);
4459
4460   /* Check if we need to set array size from compound literal size.  */
4461   if (TREE_CODE (type) == ARRAY_TYPE
4462       && TYPE_DOMAIN (type) == 0
4463       && value != error_mark_node)
4464     {
4465       tree inside_init = init;
4466
4467       STRIP_TYPE_NOPS (inside_init);
4468       inside_init = fold (inside_init);
4469
4470       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4471         {
4472           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4473
4474           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4475             {
4476               /* For int foo[] = (int [3]){1}; we need to set array size
4477                  now since later on array initializer will be just the
4478                  brace enclosed list of the compound literal.  */
4479               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4480               TREE_TYPE (decl) = type;
4481               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4482               layout_type (type);
4483               layout_decl (cldecl, 0);
4484             }
4485         }
4486     }
4487 }
4488 \f
4489 /* Methods for storing and printing names for error messages.  */
4490
4491 /* Implement a spelling stack that allows components of a name to be pushed
4492    and popped.  Each element on the stack is this structure.  */
4493
4494 struct spelling
4495 {
4496   int kind;
4497   union
4498     {
4499       unsigned HOST_WIDE_INT i;
4500       const char *s;
4501     } u;
4502 };
4503
4504 #define SPELLING_STRING 1
4505 #define SPELLING_MEMBER 2
4506 #define SPELLING_BOUNDS 3
4507
4508 static struct spelling *spelling;       /* Next stack element (unused).  */
4509 static struct spelling *spelling_base;  /* Spelling stack base.  */
4510 static int spelling_size;               /* Size of the spelling stack.  */
4511
4512 /* Macros to save and restore the spelling stack around push_... functions.
4513    Alternative to SAVE_SPELLING_STACK.  */
4514
4515 #define SPELLING_DEPTH() (spelling - spelling_base)
4516 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4517
4518 /* Push an element on the spelling stack with type KIND and assign VALUE
4519    to MEMBER.  */
4520
4521 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4522 {                                                                       \
4523   int depth = SPELLING_DEPTH ();                                        \
4524                                                                         \
4525   if (depth >= spelling_size)                                           \
4526     {                                                                   \
4527       spelling_size += 10;                                              \
4528       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4529                                   spelling_size);                       \
4530       RESTORE_SPELLING_DEPTH (depth);                                   \
4531     }                                                                   \
4532                                                                         \
4533   spelling->kind = (KIND);                                              \
4534   spelling->MEMBER = (VALUE);                                           \
4535   spelling++;                                                           \
4536 }
4537
4538 /* Push STRING on the stack.  Printed literally.  */
4539
4540 static void
4541 push_string (const char *string)
4542 {
4543   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4544 }
4545
4546 /* Push a member name on the stack.  Printed as '.' STRING.  */
4547
4548 static void
4549 push_member_name (tree decl)
4550 {
4551   const char *const string
4552     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4553   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4554 }
4555
4556 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4557
4558 static void
4559 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4560 {
4561   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4562 }
4563
4564 /* Compute the maximum size in bytes of the printed spelling.  */
4565
4566 static int
4567 spelling_length (void)
4568 {
4569   int size = 0;
4570   struct spelling *p;
4571
4572   for (p = spelling_base; p < spelling; p++)
4573     {
4574       if (p->kind == SPELLING_BOUNDS)
4575         size += 25;
4576       else
4577         size += strlen (p->u.s) + 1;
4578     }
4579
4580   return size;
4581 }
4582
4583 /* Print the spelling to BUFFER and return it.  */
4584
4585 static char *
4586 print_spelling (char *buffer)
4587 {
4588   char *d = buffer;
4589   struct spelling *p;
4590
4591   for (p = spelling_base; p < spelling; p++)
4592     if (p->kind == SPELLING_BOUNDS)
4593       {
4594         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4595         d += strlen (d);
4596       }
4597     else
4598       {
4599         const char *s;
4600         if (p->kind == SPELLING_MEMBER)
4601           *d++ = '.';
4602         for (s = p->u.s; (*d = *s++); d++)
4603           ;
4604       }
4605   *d++ = '\0';
4606   return buffer;
4607 }
4608
4609 /* Issue an error message for a bad initializer component.
4610    MSGID identifies the message.
4611    The component name is taken from the spelling stack.  */
4612
4613 void
4614 error_init (const char *msgid)
4615 {
4616   char *ofwhat;
4617
4618   error ("%s", _(msgid));
4619   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4620   if (*ofwhat)
4621     error ("(near initialization for %qs)", ofwhat);
4622 }
4623
4624 /* Issue a pedantic warning for a bad initializer component.
4625    MSGID identifies the message.
4626    The component name is taken from the spelling stack.  */
4627
4628 void
4629 pedwarn_init (const char *msgid)
4630 {
4631   char *ofwhat;
4632
4633   pedwarn ("%s", _(msgid));
4634   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4635   if (*ofwhat)
4636     pedwarn ("(near initialization for %qs)", ofwhat);
4637 }
4638
4639 /* Issue a warning for a bad initializer component.
4640
4641    OPT is the OPT_W* value corresponding to the warning option that
4642    controls this warning.  MSGID identifies the message.  The
4643    component name is taken from the spelling stack.  */
4644
4645 static void
4646 warning_init (int opt, const char *msgid)
4647 {
4648   char *ofwhat;
4649
4650   warning (opt, "%s", _(msgid));
4651   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4652   if (*ofwhat)
4653     warning (opt, "(near initialization for %qs)", ofwhat);
4654 }
4655 \f
4656 /* If TYPE is an array type and EXPR is a parenthesized string
4657    constant, warn if pedantic that EXPR is being used to initialize an
4658    object of type TYPE.  */
4659
4660 void
4661 maybe_warn_string_init (tree type, struct c_expr expr)
4662 {
4663   if (pedantic
4664       && TREE_CODE (type) == ARRAY_TYPE
4665       && TREE_CODE (expr.value) == STRING_CST
4666       && expr.original_code != STRING_CST)
4667     pedwarn_init ("array initialized from parenthesized string constant");
4668 }
4669
4670 /* Digest the parser output INIT as an initializer for type TYPE.
4671    Return a C expression of type TYPE to represent the initial value.
4672
4673    If INIT is a string constant, STRICT_STRING is true if it is
4674    unparenthesized or we should not warn here for it being parenthesized.
4675    For other types of INIT, STRICT_STRING is not used.
4676
4677    REQUIRE_CONSTANT requests an error if non-constant initializers or
4678    elements are seen.  */
4679
4680 static tree
4681 digest_init (tree type, tree init, bool strict_string, int require_constant)
4682 {
4683   enum tree_code code = TREE_CODE (type);
4684   tree inside_init = init;
4685
4686   if (type == error_mark_node
4687       || !init
4688       || init == error_mark_node
4689       || TREE_TYPE (init) == error_mark_node)
4690     return error_mark_node;
4691
4692   STRIP_TYPE_NOPS (inside_init);
4693
4694   inside_init = fold (inside_init);
4695
4696   /* Initialization of an array of chars from a string constant
4697      optionally enclosed in braces.  */
4698
4699   if (code == ARRAY_TYPE && inside_init
4700       && TREE_CODE (inside_init) == STRING_CST)
4701     {
4702       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4703       /* Note that an array could be both an array of character type
4704          and an array of wchar_t if wchar_t is signed char or unsigned
4705          char.  */
4706       bool char_array = (typ1 == char_type_node
4707                          || typ1 == signed_char_type_node
4708                          || typ1 == unsigned_char_type_node);
4709       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4710       if (char_array || wchar_array)
4711         {
4712           struct c_expr expr;
4713           bool char_string;
4714           expr.value = inside_init;
4715           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4716           maybe_warn_string_init (type, expr);
4717
4718           char_string
4719             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4720                == char_type_node);
4721
4722           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4723                          TYPE_MAIN_VARIANT (type)))
4724             return inside_init;
4725
4726           if (!wchar_array && !char_string)
4727             {
4728               error_init ("char-array initialized from wide string");
4729               return error_mark_node;
4730             }
4731           if (char_string && !char_array)
4732             {
4733               error_init ("wchar_t-array initialized from non-wide string");
4734               return error_mark_node;
4735             }
4736
4737           TREE_TYPE (inside_init) = type;
4738           if (TYPE_DOMAIN (type) != 0
4739               && TYPE_SIZE (type) != 0
4740               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4741               /* Subtract 1 (or sizeof (wchar_t))
4742                  because it's ok to ignore the terminating null char
4743                  that is counted in the length of the constant.  */
4744               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4745                                        TREE_STRING_LENGTH (inside_init)
4746                                        - ((TYPE_PRECISION (typ1)
4747                                            != TYPE_PRECISION (char_type_node))
4748                                           ? (TYPE_PRECISION (wchar_type_node)
4749                                              / BITS_PER_UNIT)
4750                                           : 1)))
4751             pedwarn_init ("initializer-string for array of chars is too long");
4752
4753           return inside_init;
4754         }
4755       else if (INTEGRAL_TYPE_P (typ1))
4756         {
4757           error_init ("array of inappropriate type initialized "
4758                       "from string constant");
4759           return error_mark_node;
4760         }
4761     }
4762
4763   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4764      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4765      below and handle as a constructor.  */
4766   if (code == VECTOR_TYPE
4767       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4768       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4769       && TREE_CONSTANT (inside_init))
4770     {
4771       if (TREE_CODE (inside_init) == VECTOR_CST
4772           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4773                         TYPE_MAIN_VARIANT (type)))
4774         return inside_init;
4775
4776       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4777         {
4778           unsigned HOST_WIDE_INT ix;
4779           tree value;
4780           bool constant_p = true;
4781
4782           /* Iterate through elements and check if all constructor
4783              elements are *_CSTs.  */
4784           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4785             if (!CONSTANT_CLASS_P (value))
4786               {
4787                 constant_p = false;
4788                 break;
4789               }
4790
4791           if (constant_p)
4792             return build_vector_from_ctor (type,
4793                                            CONSTRUCTOR_ELTS (inside_init));
4794         }
4795     }
4796
4797   /* Any type can be initialized
4798      from an expression of the same type, optionally with braces.  */
4799
4800   if (inside_init && TREE_TYPE (inside_init) != 0
4801       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4802                      TYPE_MAIN_VARIANT (type))
4803           || (code == ARRAY_TYPE
4804               && comptypes (TREE_TYPE (inside_init), type))
4805           || (code == VECTOR_TYPE
4806               && comptypes (TREE_TYPE (inside_init), type))
4807           || (code == POINTER_TYPE
4808               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4809               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4810                             TREE_TYPE (type)))))
4811     {
4812       if (code == POINTER_TYPE)
4813         {
4814           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4815             {
4816               if (TREE_CODE (inside_init) == STRING_CST
4817                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4818                 inside_init = array_to_pointer_conversion (inside_init);
4819               else
4820                 {
4821                   error_init ("invalid use of non-lvalue array");
4822                   return error_mark_node;
4823                 }
4824             }
4825         }
4826
4827       if (code == VECTOR_TYPE)
4828         /* Although the types are compatible, we may require a
4829            conversion.  */
4830         inside_init = convert (type, inside_init);
4831
4832       if (require_constant
4833           && (code == VECTOR_TYPE || !flag_isoc99)
4834           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4835         {
4836           /* As an extension, allow initializing objects with static storage
4837              duration with compound literals (which are then treated just as
4838              the brace enclosed list they contain).  Also allow this for
4839              vectors, as we can only assign them with compound literals.  */
4840           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4841           inside_init = DECL_INITIAL (decl);
4842         }
4843
4844       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4845           && TREE_CODE (inside_init) != CONSTRUCTOR)
4846         {
4847           error_init ("array initialized from non-constant array expression");
4848           return error_mark_node;
4849         }
4850
4851       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4852         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4853
4854       /* Compound expressions can only occur here if -pedantic or
4855          -pedantic-errors is specified.  In the later case, we always want
4856          an error.  In the former case, we simply want a warning.  */
4857       if (require_constant && pedantic
4858           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4859         {
4860           inside_init
4861             = valid_compound_expr_initializer (inside_init,
4862                                                TREE_TYPE (inside_init));
4863           if (inside_init == error_mark_node)
4864             error_init ("initializer element is not constant");
4865           else
4866             pedwarn_init ("initializer element is not constant");
4867           if (flag_pedantic_errors)
4868             inside_init = error_mark_node;
4869         }
4870       else if (require_constant
4871                && !initializer_constant_valid_p (inside_init,
4872                                                  TREE_TYPE (inside_init)))
4873         {
4874           error_init ("initializer element is not constant");
4875           inside_init = error_mark_node;
4876         }
4877
4878       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4879       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4880         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4881                                               NULL_TREE, 0);
4882       return inside_init;
4883     }
4884
4885   /* Handle scalar types, including conversions.  */
4886
4887   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4888       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4889       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4890     {
4891       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4892           && (TREE_CODE (init) == STRING_CST
4893               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4894         init = array_to_pointer_conversion (init);
4895       inside_init
4896         = convert_for_assignment (type, init, ic_init,
4897                                   NULL_TREE, NULL_TREE, 0);
4898
4899       /* Check to see if we have already given an error message.  */
4900       if (inside_init == error_mark_node)
4901         ;
4902       else if (require_constant && !TREE_CONSTANT (inside_init))
4903         {
4904           error_init ("initializer element is not constant");
4905           inside_init = error_mark_node;
4906         }
4907       else if (require_constant
4908                && !initializer_constant_valid_p (inside_init,
4909                                                  TREE_TYPE (inside_init)))
4910         {
4911           error_init ("initializer element is not computable at load time");
4912           inside_init = error_mark_node;
4913         }
4914
4915       return inside_init;
4916     }
4917
4918   /* Come here only for records and arrays.  */
4919
4920   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4921     {
4922       error_init ("variable-sized object may not be initialized");
4923       return error_mark_node;
4924     }
4925
4926   error_init ("invalid initializer");
4927   return error_mark_node;
4928 }
4929 \f
4930 /* Handle initializers that use braces.  */
4931
4932 /* Type of object we are accumulating a constructor for.
4933    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4934 static tree constructor_type;
4935
4936 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4937    left to fill.  */
4938 static tree constructor_fields;
4939
4940 /* For an ARRAY_TYPE, this is the specified index
4941    at which to store the next element we get.  */
4942 static tree constructor_index;
4943
4944 /* For an ARRAY_TYPE, this is the maximum index.  */
4945 static tree constructor_max_index;
4946
4947 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4948 static tree constructor_unfilled_fields;
4949
4950 /* For an ARRAY_TYPE, this is the index of the first element
4951    not yet written out.  */
4952 static tree constructor_unfilled_index;
4953
4954 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4955    This is so we can generate gaps between fields, when appropriate.  */
4956 static tree constructor_bit_index;
4957
4958 /* If we are saving up the elements rather than allocating them,
4959    this is the list of elements so far (in reverse order,
4960    most recent first).  */
4961 static VEC(constructor_elt,gc) *constructor_elements;
4962
4963 /* 1 if constructor should be incrementally stored into a constructor chain,
4964    0 if all the elements should be kept in AVL tree.  */
4965 static int constructor_incremental;
4966
4967 /* 1 if so far this constructor's elements are all compile-time constants.  */
4968 static int constructor_constant;
4969
4970 /* 1 if so far this constructor's elements are all valid address constants.  */
4971 static int constructor_simple;
4972
4973 /* 1 if this constructor is erroneous so far.  */
4974 static int constructor_erroneous;
4975
4976 /* Structure for managing pending initializer elements, organized as an
4977    AVL tree.  */
4978
4979 struct init_node
4980 {
4981   struct init_node *left, *right;
4982   struct init_node *parent;
4983   int balance;
4984   tree purpose;
4985   tree value;
4986 };
4987
4988 /* Tree of pending elements at this constructor level.
4989    These are elements encountered out of order
4990    which belong at places we haven't reached yet in actually
4991    writing the output.
4992    Will never hold tree nodes across GC runs.  */
4993 static struct init_node *constructor_pending_elts;
4994
4995 /* The SPELLING_DEPTH of this constructor.  */
4996 static int constructor_depth;
4997
4998 /* DECL node for which an initializer is being read.
4999    0 means we are reading a constructor expression
5000    such as (struct foo) {...}.  */
5001 static tree constructor_decl;
5002
5003 /* Nonzero if this is an initializer for a top-level decl.  */
5004 static int constructor_top_level;
5005
5006 /* Nonzero if there were any member designators in this initializer.  */
5007 static int constructor_designated;
5008
5009 /* Nesting depth of designator list.  */
5010 static int designator_depth;
5011
5012 /* Nonzero if there were diagnosed errors in this designator list.  */
5013 static int designator_erroneous;
5014
5015 \f
5016 /* This stack has a level for each implicit or explicit level of
5017    structuring in the initializer, including the outermost one.  It
5018    saves the values of most of the variables above.  */
5019
5020 struct constructor_range_stack;
5021
5022 struct constructor_stack
5023 {
5024   struct constructor_stack *next;
5025   tree type;
5026   tree fields;
5027   tree index;
5028   tree max_index;
5029   tree unfilled_index;
5030   tree unfilled_fields;
5031   tree bit_index;
5032   VEC(constructor_elt,gc) *elements;
5033   struct init_node *pending_elts;
5034   int offset;
5035   int depth;
5036   /* If value nonzero, this value should replace the entire
5037      constructor at this level.  */
5038   struct c_expr replacement_value;
5039   struct constructor_range_stack *range_stack;
5040   char constant;
5041   char simple;
5042   char implicit;
5043   char erroneous;
5044   char outer;
5045   char incremental;
5046   char designated;
5047 };
5048
5049 static struct constructor_stack *constructor_stack;
5050
5051 /* This stack represents designators from some range designator up to
5052    the last designator in the list.  */
5053
5054 struct constructor_range_stack
5055 {
5056   struct constructor_range_stack *next, *prev;
5057   struct constructor_stack *stack;
5058   tree range_start;
5059   tree index;
5060   tree range_end;
5061   tree fields;
5062 };
5063
5064 static struct constructor_range_stack *constructor_range_stack;
5065
5066 /* This stack records separate initializers that are nested.
5067    Nested initializers can't happen in ANSI C, but GNU C allows them
5068    in cases like { ... (struct foo) { ... } ... }.  */
5069
5070 struct initializer_stack
5071 {
5072   struct initializer_stack *next;
5073   tree decl;
5074   struct constructor_stack *constructor_stack;
5075   struct constructor_range_stack *constructor_range_stack;
5076   VEC(constructor_elt,gc) *elements;
5077   struct spelling *spelling;
5078   struct spelling *spelling_base;
5079   int spelling_size;
5080   char top_level;
5081   char require_constant_value;
5082   char require_constant_elements;
5083 };
5084
5085 static struct initializer_stack *initializer_stack;
5086 \f
5087 /* Prepare to parse and output the initializer for variable DECL.  */
5088
5089 void
5090 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5091 {
5092   const char *locus;
5093   struct initializer_stack *p = XNEW (struct initializer_stack);
5094
5095   p->decl = constructor_decl;
5096   p->require_constant_value = require_constant_value;
5097   p->require_constant_elements = require_constant_elements;
5098   p->constructor_stack = constructor_stack;
5099   p->constructor_range_stack = constructor_range_stack;
5100   p->elements = constructor_elements;
5101   p->spelling = spelling;
5102   p->spelling_base = spelling_base;
5103   p->spelling_size = spelling_size;
5104   p->top_level = constructor_top_level;
5105   p->next = initializer_stack;
5106   initializer_stack = p;
5107
5108   constructor_decl = decl;
5109   constructor_designated = 0;
5110   constructor_top_level = top_level;
5111
5112   if (decl != 0 && decl != error_mark_node)
5113     {
5114       require_constant_value = TREE_STATIC (decl);
5115       require_constant_elements
5116         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5117            /* For a scalar, you can always use any value to initialize,
5118               even within braces.  */
5119            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5120                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5121                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5122                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5123       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5124     }
5125   else
5126     {
5127       require_constant_value = 0;
5128       require_constant_elements = 0;
5129       locus = "(anonymous)";
5130     }
5131
5132   constructor_stack = 0;
5133   constructor_range_stack = 0;
5134
5135   missing_braces_mentioned = 0;
5136
5137   spelling_base = 0;
5138   spelling_size = 0;
5139   RESTORE_SPELLING_DEPTH (0);
5140
5141   if (locus)
5142     push_string (locus);
5143 }
5144
5145 void
5146 finish_init (void)
5147 {
5148   struct initializer_stack *p = initializer_stack;
5149
5150   /* Free the whole constructor stack of this initializer.  */
5151   while (constructor_stack)
5152     {
5153       struct constructor_stack *q = constructor_stack;
5154       constructor_stack = q->next;
5155       free (q);
5156     }
5157
5158   gcc_assert (!constructor_range_stack);
5159
5160   /* Pop back to the data of the outer initializer (if any).  */
5161   free (spelling_base);
5162
5163   constructor_decl = p->decl;
5164   require_constant_value = p->require_constant_value;
5165   require_constant_elements = p->require_constant_elements;
5166   constructor_stack = p->constructor_stack;
5167   constructor_range_stack = p->constructor_range_stack;
5168   constructor_elements = p->elements;
5169   spelling = p->spelling;
5170   spelling_base = p->spelling_base;
5171   spelling_size = p->spelling_size;
5172   constructor_top_level = p->top_level;
5173   initializer_stack = p->next;
5174   free (p);
5175 }
5176 \f
5177 /* Call here when we see the initializer is surrounded by braces.
5178    This is instead of a call to push_init_level;
5179    it is matched by a call to pop_init_level.
5180
5181    TYPE is the type to initialize, for a constructor expression.
5182    For an initializer for a decl, TYPE is zero.  */
5183
5184 void
5185 really_start_incremental_init (tree type)
5186 {
5187   struct constructor_stack *p = XNEW (struct constructor_stack);
5188
5189   if (type == 0)
5190     type = TREE_TYPE (constructor_decl);
5191
5192   if (targetm.vector_opaque_p (type))
5193     error ("opaque vector types cannot be initialized");
5194
5195   p->type = constructor_type;
5196   p->fields = constructor_fields;
5197   p->index = constructor_index;
5198   p->max_index = constructor_max_index;
5199   p->unfilled_index = constructor_unfilled_index;
5200   p->unfilled_fields = constructor_unfilled_fields;
5201   p->bit_index = constructor_bit_index;
5202   p->elements = constructor_elements;
5203   p->constant = constructor_constant;
5204   p->simple = constructor_simple;
5205   p->erroneous = constructor_erroneous;
5206   p->pending_elts = constructor_pending_elts;
5207   p->depth = constructor_depth;
5208   p->replacement_value.value = 0;
5209   p->replacement_value.original_code = ERROR_MARK;
5210   p->implicit = 0;
5211   p->range_stack = 0;
5212   p->outer = 0;
5213   p->incremental = constructor_incremental;
5214   p->designated = constructor_designated;
5215   p->next = 0;
5216   constructor_stack = p;
5217
5218   constructor_constant = 1;
5219   constructor_simple = 1;
5220   constructor_depth = SPELLING_DEPTH ();
5221   constructor_elements = 0;
5222   constructor_pending_elts = 0;
5223   constructor_type = type;
5224   constructor_incremental = 1;
5225   constructor_designated = 0;
5226   designator_depth = 0;
5227   designator_erroneous = 0;
5228
5229   if (TREE_CODE (constructor_type) == RECORD_TYPE
5230       || TREE_CODE (constructor_type) == UNION_TYPE)
5231     {
5232       constructor_fields = TYPE_FIELDS (constructor_type);
5233       /* Skip any nameless bit fields at the beginning.  */
5234       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5235              && DECL_NAME (constructor_fields) == 0)
5236         constructor_fields = TREE_CHAIN (constructor_fields);
5237
5238       constructor_unfilled_fields = constructor_fields;
5239       constructor_bit_index = bitsize_zero_node;
5240     }
5241   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5242     {
5243       if (TYPE_DOMAIN (constructor_type))
5244         {
5245           constructor_max_index
5246             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5247
5248           /* Detect non-empty initializations of zero-length arrays.  */
5249           if (constructor_max_index == NULL_TREE
5250               && TYPE_SIZE (constructor_type))
5251             constructor_max_index = build_int_cst (NULL_TREE, -1);
5252
5253           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5254              to initialize VLAs will cause a proper error; avoid tree
5255              checking errors as well by setting a safe value.  */
5256           if (constructor_max_index
5257               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5258             constructor_max_index = build_int_cst (NULL_TREE, -1);
5259
5260           constructor_index
5261             = convert (bitsizetype,
5262                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5263         }
5264       else
5265         {
5266           constructor_index = bitsize_zero_node;
5267           constructor_max_index = NULL_TREE;
5268         }
5269
5270       constructor_unfilled_index = constructor_index;
5271     }
5272   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5273     {
5274       /* Vectors are like simple fixed-size arrays.  */
5275       constructor_max_index =
5276         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5277       constructor_index = bitsize_zero_node;
5278       constructor_unfilled_index = constructor_index;
5279     }
5280   else
5281     {
5282       /* Handle the case of int x = {5}; */
5283       constructor_fields = constructor_type;
5284       constructor_unfilled_fields = constructor_type;
5285     }
5286 }
5287 \f
5288 /* Push down into a subobject, for initialization.
5289    If this is for an explicit set of braces, IMPLICIT is 0.
5290    If it is because the next element belongs at a lower level,
5291    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5292
5293 void
5294 push_init_level (int implicit)
5295 {
5296   struct constructor_stack *p;
5297   tree value = NULL_TREE;
5298
5299   /* If we've exhausted any levels that didn't have braces,
5300      pop them now.  If implicit == 1, this will have been done in
5301      process_init_element; do not repeat it here because in the case
5302      of excess initializers for an empty aggregate this leads to an
5303      infinite cycle of popping a level and immediately recreating
5304      it.  */
5305   if (implicit != 1)
5306     {
5307       while (constructor_stack->implicit)
5308         {
5309           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5310                || TREE_CODE (constructor_type) == UNION_TYPE)
5311               && constructor_fields == 0)
5312             process_init_element (pop_init_level (1));
5313           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5314                    && constructor_max_index
5315                    && tree_int_cst_lt (constructor_max_index,
5316                                        constructor_index))
5317             process_init_element (pop_init_level (1));
5318           else
5319             break;
5320         }
5321     }
5322
5323   /* Unless this is an explicit brace, we need to preserve previous
5324      content if any.  */
5325   if (implicit)
5326     {
5327       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5328            || TREE_CODE (constructor_type) == UNION_TYPE)
5329           && constructor_fields)
5330         value = find_init_member (constructor_fields);
5331       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5332         value = find_init_member (constructor_index);
5333     }
5334
5335   p = XNEW (struct constructor_stack);
5336   p->type = constructor_type;
5337   p->fields = constructor_fields;
5338   p->index = constructor_index;
5339   p->max_index = constructor_max_index;
5340   p->unfilled_index = constructor_unfilled_index;
5341   p->unfilled_fields = constructor_unfilled_fields;
5342   p->bit_index = constructor_bit_index;
5343   p->elements = constructor_elements;
5344   p->constant = constructor_constant;
5345   p->simple = constructor_simple;
5346   p->erroneous = constructor_erroneous;
5347   p->pending_elts = constructor_pending_elts;
5348   p->depth = constructor_depth;
5349   p->replacement_value.value = 0;
5350   p->replacement_value.original_code = ERROR_MARK;
5351   p->implicit = implicit;
5352   p->outer = 0;
5353   p->incremental = constructor_incremental;
5354   p->designated = constructor_designated;
5355   p->next = constructor_stack;
5356   p->range_stack = 0;
5357   constructor_stack = p;
5358
5359   constructor_constant = 1;
5360   constructor_simple = 1;
5361   constructor_depth = SPELLING_DEPTH ();
5362   constructor_elements = 0;
5363   constructor_incremental = 1;
5364   constructor_designated = 0;
5365   constructor_pending_elts = 0;
5366   if (!implicit)
5367     {
5368       p->range_stack = constructor_range_stack;
5369       constructor_range_stack = 0;
5370       designator_depth = 0;
5371       designator_erroneous = 0;
5372     }
5373
5374   /* Don't die if an entire brace-pair level is superfluous
5375      in the containing level.  */
5376   if (constructor_type == 0)
5377     ;
5378   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5379            || TREE_CODE (constructor_type) == UNION_TYPE)
5380     {
5381       /* Don't die if there are extra init elts at the end.  */
5382       if (constructor_fields == 0)
5383         constructor_type = 0;
5384       else
5385         {
5386           constructor_type = TREE_TYPE (constructor_fields);
5387           push_member_name (constructor_fields);
5388           constructor_depth++;
5389         }
5390     }
5391   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5392     {
5393       constructor_type = TREE_TYPE (constructor_type);
5394       push_array_bounds (tree_low_cst (constructor_index, 1));
5395       constructor_depth++;
5396     }
5397
5398   if (constructor_type == 0)
5399     {
5400       error_init ("extra brace group at end of initializer");
5401       constructor_fields = 0;
5402       constructor_unfilled_fields = 0;
5403       return;
5404     }
5405
5406   if (value && TREE_CODE (value) == CONSTRUCTOR)
5407     {
5408       constructor_constant = TREE_CONSTANT (value);
5409       constructor_simple = TREE_STATIC (value);
5410       constructor_elements = CONSTRUCTOR_ELTS (value);
5411       if (!VEC_empty (constructor_elt, constructor_elements)
5412           && (TREE_CODE (constructor_type) == RECORD_TYPE
5413               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5414         set_nonincremental_init ();
5415     }
5416
5417   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5418     {
5419       missing_braces_mentioned = 1;
5420       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5421     }
5422
5423   if (TREE_CODE (constructor_type) == RECORD_TYPE
5424            || TREE_CODE (constructor_type) == UNION_TYPE)
5425     {
5426       constructor_fields = TYPE_FIELDS (constructor_type);
5427       /* Skip any nameless bit fields at the beginning.  */
5428       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5429              && DECL_NAME (constructor_fields) == 0)
5430         constructor_fields = TREE_CHAIN (constructor_fields);
5431
5432       constructor_unfilled_fields = constructor_fields;
5433       constructor_bit_index = bitsize_zero_node;
5434     }
5435   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5436     {
5437       /* Vectors are like simple fixed-size arrays.  */
5438       constructor_max_index =
5439         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5440       constructor_index = convert (bitsizetype, integer_zero_node);
5441       constructor_unfilled_index = constructor_index;
5442     }
5443   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5444     {
5445       if (TYPE_DOMAIN (constructor_type))
5446         {
5447           constructor_max_index
5448             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5449
5450           /* Detect non-empty initializations of zero-length arrays.  */
5451           if (constructor_max_index == NULL_TREE
5452               && TYPE_SIZE (constructor_type))
5453             constructor_max_index = build_int_cst (NULL_TREE, -1);
5454
5455           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5456              to initialize VLAs will cause a proper error; avoid tree
5457              checking errors as well by setting a safe value.  */
5458           if (constructor_max_index
5459               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5460             constructor_max_index = build_int_cst (NULL_TREE, -1);
5461
5462           constructor_index
5463             = convert (bitsizetype,
5464                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5465         }
5466       else
5467         constructor_index = bitsize_zero_node;
5468
5469       constructor_unfilled_index = constructor_index;
5470       if (value && TREE_CODE (value) == STRING_CST)
5471         {
5472           /* We need to split the char/wchar array into individual
5473              characters, so that we don't have to special case it
5474              everywhere.  */
5475           set_nonincremental_init_from_string (value);
5476         }
5477     }
5478   else
5479     {
5480       if (constructor_type != error_mark_node)
5481         warning_init (0, "braces around scalar initializer");
5482       constructor_fields = constructor_type;
5483       constructor_unfilled_fields = constructor_type;
5484     }
5485 }
5486
5487 /* At the end of an implicit or explicit brace level,
5488    finish up that level of constructor.  If a single expression
5489    with redundant braces initialized that level, return the
5490    c_expr structure for that expression.  Otherwise, the original_code
5491    element is set to ERROR_MARK.
5492    If we were outputting the elements as they are read, return 0 as the value
5493    from inner levels (process_init_element ignores that),
5494    but return error_mark_node as the value from the outermost level
5495    (that's what we want to put in DECL_INITIAL).
5496    Otherwise, return a CONSTRUCTOR expression as the value.  */
5497
5498 struct c_expr
5499 pop_init_level (int implicit)
5500 {
5501   struct constructor_stack *p;
5502   struct c_expr ret;
5503   ret.value = 0;
5504   ret.original_code = ERROR_MARK;
5505
5506   if (implicit == 0)
5507     {
5508       /* When we come to an explicit close brace,
5509          pop any inner levels that didn't have explicit braces.  */
5510       while (constructor_stack->implicit)
5511         process_init_element (pop_init_level (1));
5512
5513       gcc_assert (!constructor_range_stack);
5514     }
5515
5516   /* Now output all pending elements.  */
5517   constructor_incremental = 1;
5518   output_pending_init_elements (1);
5519
5520   p = constructor_stack;
5521
5522   /* Error for initializing a flexible array member, or a zero-length
5523      array member in an inappropriate context.  */
5524   if (constructor_type && constructor_fields
5525       && TREE_CODE (constructor_type) == ARRAY_TYPE
5526       && TYPE_DOMAIN (constructor_type)
5527       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5528     {
5529       /* Silently discard empty initializations.  The parser will
5530          already have pedwarned for empty brackets.  */
5531       if (integer_zerop (constructor_unfilled_index))
5532         constructor_type = NULL_TREE;
5533       else
5534         {
5535           gcc_assert (!TYPE_SIZE (constructor_type));
5536
5537           if (constructor_depth > 2)
5538             error_init ("initialization of flexible array member in a nested context");
5539           else if (pedantic)
5540             pedwarn_init ("initialization of a flexible array member");
5541
5542           /* We have already issued an error message for the existence
5543              of a flexible array member not at the end of the structure.
5544              Discard the initializer so that we do not die later.  */
5545           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5546             constructor_type = NULL_TREE;
5547         }
5548     }
5549
5550   /* Warn when some struct elements are implicitly initialized to zero.  */
5551   if (warn_missing_field_initializers
5552       && constructor_type
5553       && TREE_CODE (constructor_type) == RECORD_TYPE
5554       && constructor_unfilled_fields)
5555     {
5556         /* Do not warn for flexible array members or zero-length arrays.  */
5557         while (constructor_unfilled_fields
5558                && (!DECL_SIZE (constructor_unfilled_fields)
5559                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5560           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5561
5562         /* Do not warn if this level of the initializer uses member
5563            designators; it is likely to be deliberate.  */
5564         if (constructor_unfilled_fields && !constructor_designated)
5565           {
5566             push_member_name (constructor_unfilled_fields);
5567             warning_init (OPT_Wmissing_field_initializers,
5568                           "missing initializer");
5569             RESTORE_SPELLING_DEPTH (constructor_depth);
5570           }
5571     }
5572
5573   /* Pad out the end of the structure.  */
5574   if (p->replacement_value.value)
5575     /* If this closes a superfluous brace pair,
5576        just pass out the element between them.  */
5577     ret = p->replacement_value;
5578   else if (constructor_type == 0)
5579     ;
5580   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5581            && TREE_CODE (constructor_type) != UNION_TYPE
5582            && TREE_CODE (constructor_type) != ARRAY_TYPE
5583            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5584     {
5585       /* A nonincremental scalar initializer--just return
5586          the element, after verifying there is just one.  */
5587       if (VEC_empty (constructor_elt,constructor_elements))
5588         {
5589           if (!constructor_erroneous)
5590             error_init ("empty scalar initializer");
5591           ret.value = error_mark_node;
5592         }
5593       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5594         {
5595           error_init ("extra elements in scalar initializer");
5596           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5597         }
5598       else
5599         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5600     }
5601   else
5602     {
5603       if (constructor_erroneous)
5604         ret.value = error_mark_node;
5605       else
5606         {
5607           ret.value = build_constructor (constructor_type,
5608                                          constructor_elements);
5609           if (constructor_constant)
5610             TREE_CONSTANT (ret.value) = 1;
5611           if (constructor_constant && constructor_simple)
5612             TREE_STATIC (ret.value) = 1;
5613         }
5614     }
5615
5616   constructor_type = p->type;
5617   constructor_fields = p->fields;
5618   constructor_index = p->index;
5619   constructor_max_index = p->max_index;
5620   constructor_unfilled_index = p->unfilled_index;
5621   constructor_unfilled_fields = p->unfilled_fields;
5622   constructor_bit_index = p->bit_index;
5623   constructor_elements = p->elements;
5624   constructor_constant = p->constant;
5625   constructor_simple = p->simple;
5626   constructor_erroneous = p->erroneous;
5627   constructor_incremental = p->incremental;
5628   constructor_designated = p->designated;
5629   constructor_pending_elts = p->pending_elts;
5630   constructor_depth = p->depth;
5631   if (!p->implicit)
5632     constructor_range_stack = p->range_stack;
5633   RESTORE_SPELLING_DEPTH (constructor_depth);
5634
5635   constructor_stack = p->next;
5636   free (p);
5637
5638   if (ret.value == 0 && constructor_stack == 0)
5639     ret.value = error_mark_node;
5640   return ret;
5641 }
5642
5643 /* Common handling for both array range and field name designators.
5644    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5645
5646 static int
5647 set_designator (int array)
5648 {
5649   tree subtype;
5650   enum tree_code subcode;
5651
5652   /* Don't die if an entire brace-pair level is superfluous
5653      in the containing level.  */
5654   if (constructor_type == 0)
5655     return 1;
5656
5657   /* If there were errors in this designator list already, bail out
5658      silently.  */
5659   if (designator_erroneous)
5660     return 1;
5661
5662   if (!designator_depth)
5663     {
5664       gcc_assert (!constructor_range_stack);
5665
5666       /* Designator list starts at the level of closest explicit
5667          braces.  */
5668       while (constructor_stack->implicit)
5669         process_init_element (pop_init_level (1));
5670       constructor_designated = 1;
5671       return 0;
5672     }
5673
5674   switch (TREE_CODE (constructor_type))
5675     {
5676     case  RECORD_TYPE:
5677     case  UNION_TYPE:
5678       subtype = TREE_TYPE (constructor_fields);
5679       if (subtype != error_mark_node)
5680         subtype = TYPE_MAIN_VARIANT (subtype);
5681       break;
5682     case ARRAY_TYPE:
5683       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5684       break;
5685     default:
5686       gcc_unreachable ();
5687     }
5688
5689   subcode = TREE_CODE (subtype);
5690   if (array && subcode != ARRAY_TYPE)
5691     {
5692       error_init ("array index in non-array initializer");
5693       return 1;
5694     }
5695   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5696     {
5697       error_init ("field name not in record or union initializer");
5698       return 1;
5699     }
5700
5701   constructor_designated = 1;
5702   push_init_level (2);
5703   return 0;
5704 }
5705
5706 /* If there are range designators in designator list, push a new designator
5707    to constructor_range_stack.  RANGE_END is end of such stack range or
5708    NULL_TREE if there is no range designator at this level.  */
5709
5710 static void
5711 push_range_stack (tree range_end)
5712 {
5713   struct constructor_range_stack *p;
5714
5715   p = GGC_NEW (struct constructor_range_stack);
5716   p->prev = constructor_range_stack;
5717   p->next = 0;
5718   p->fields = constructor_fields;
5719   p->range_start = constructor_index;
5720   p->index = constructor_index;
5721   p->stack = constructor_stack;
5722   p->range_end = range_end;
5723   if (constructor_range_stack)
5724     constructor_range_stack->next = p;
5725   constructor_range_stack = p;
5726 }
5727
5728 /* Within an array initializer, specify the next index to be initialized.
5729    FIRST is that index.  If LAST is nonzero, then initialize a range
5730    of indices, running from FIRST through LAST.  */
5731
5732 void
5733 set_init_index (tree first, tree last)
5734 {
5735   if (set_designator (1))
5736     return;
5737
5738   designator_erroneous = 1;
5739
5740   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5741       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5742     {
5743       error_init ("array index in initializer not of integer type");
5744       return;
5745     }
5746
5747   if (TREE_CODE (first) != INTEGER_CST)
5748     error_init ("nonconstant array index in initializer");
5749   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5750     error_init ("nonconstant array index in initializer");
5751   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5752     error_init ("array index in non-array initializer");
5753   else if (tree_int_cst_sgn (first) == -1)
5754     error_init ("array index in initializer exceeds array bounds");
5755   else if (constructor_max_index
5756            && tree_int_cst_lt (constructor_max_index, first))
5757     error_init ("array index in initializer exceeds array bounds");
5758   else
5759     {
5760       constructor_index = convert (bitsizetype, first);
5761
5762       if (last)
5763         {
5764           if (tree_int_cst_equal (first, last))
5765             last = 0;
5766           else if (tree_int_cst_lt (last, first))
5767             {
5768               error_init ("empty index range in initializer");
5769               last = 0;
5770             }
5771           else
5772             {
5773               last = convert (bitsizetype, last);
5774               if (constructor_max_index != 0
5775                   && tree_int_cst_lt (constructor_max_index, last))
5776                 {
5777                   error_init ("array index range in initializer exceeds array bounds");
5778                   last = 0;
5779                 }
5780             }
5781         }
5782
5783       designator_depth++;
5784       designator_erroneous = 0;
5785       if (constructor_range_stack || last)
5786         push_range_stack (last);
5787     }
5788 }
5789
5790 /* Within a struct initializer, specify the next field to be initialized.  */
5791
5792 void
5793 set_init_label (tree fieldname)
5794 {
5795   tree tail;
5796
5797   if (set_designator (0))
5798     return;
5799
5800   designator_erroneous = 1;
5801
5802   if (TREE_CODE (constructor_type) != RECORD_TYPE
5803       && TREE_CODE (constructor_type) != UNION_TYPE)
5804     {
5805       error_init ("field name not in record or union initializer");
5806       return;
5807     }
5808
5809   for (tail = TYPE_FIELDS (constructor_type); tail;
5810        tail = TREE_CHAIN (tail))
5811     {
5812       if (DECL_NAME (tail) == fieldname)
5813         break;
5814     }
5815
5816   if (tail == 0)
5817     error ("unknown field %qE specified in initializer", fieldname);
5818   else
5819     {
5820       constructor_fields = tail;
5821       designator_depth++;
5822       designator_erroneous = 0;
5823       if (constructor_range_stack)
5824         push_range_stack (NULL_TREE);
5825     }
5826 }
5827 \f
5828 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5829    identifies the initializer, either array index or field in a structure.
5830    VALUE is the value of that index or field.  */
5831
5832 static void
5833 add_pending_init (tree purpose, tree value)
5834 {
5835   struct init_node *p, **q, *r;
5836
5837   q = &constructor_pending_elts;
5838   p = 0;
5839
5840   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5841     {
5842       while (*q != 0)
5843         {
5844           p = *q;
5845           if (tree_int_cst_lt (purpose, p->purpose))
5846             q = &p->left;
5847           else if (tree_int_cst_lt (p->purpose, purpose))
5848             q = &p->right;
5849           else
5850             {
5851               if (TREE_SIDE_EFFECTS (p->value))
5852                 warning_init (0, "initialized field with side-effects overwritten");
5853               else if (warn_override_init)
5854                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5855               p->value = value;
5856               return;
5857             }
5858         }
5859     }
5860   else
5861     {
5862       tree bitpos;
5863
5864       bitpos = bit_position (purpose);
5865       while (*q != NULL)
5866         {
5867           p = *q;
5868           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5869             q = &p->left;
5870           else if (p->purpose != purpose)
5871             q = &p->right;
5872           else
5873             {
5874               if (TREE_SIDE_EFFECTS (p->value))
5875                 warning_init (0, "initialized field with side-effects overwritten");
5876               else if (warn_override_init)
5877                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5878               p->value = value;
5879               return;
5880             }
5881         }
5882     }
5883
5884   r = GGC_NEW (struct init_node);
5885   r->purpose = purpose;
5886   r->value = value;
5887
5888   *q = r;
5889   r->parent = p;
5890   r->left = 0;
5891   r->right = 0;
5892   r->balance = 0;
5893
5894   while (p)
5895     {
5896       struct init_node *s;
5897
5898       if (r == p->left)
5899         {
5900           if (p->balance == 0)
5901             p->balance = -1;
5902           else if (p->balance < 0)
5903             {
5904               if (r->balance < 0)
5905                 {
5906                   /* L rotation.  */
5907                   p->left = r->right;
5908                   if (p->left)
5909                     p->left->parent = p;
5910                   r->right = p;
5911
5912                   p->balance = 0;
5913                   r->balance = 0;
5914
5915                   s = p->parent;
5916                   p->parent = r;
5917                   r->parent = s;
5918                   if (s)
5919                     {
5920                       if (s->left == p)
5921                         s->left = r;
5922                       else
5923                         s->right = r;
5924                     }
5925                   else
5926                     constructor_pending_elts = r;
5927                 }
5928               else
5929                 {
5930                   /* LR rotation.  */
5931                   struct init_node *t = r->right;
5932
5933                   r->right = t->left;
5934                   if (r->right)
5935                     r->right->parent = r;
5936                   t->left = r;
5937
5938                   p->left = t->right;
5939                   if (p->left)
5940                     p->left->parent = p;
5941                   t->right = p;
5942
5943                   p->balance = t->balance < 0;
5944                   r->balance = -(t->balance > 0);
5945                   t->balance = 0;
5946
5947                   s = p->parent;
5948                   p->parent = t;
5949                   r->parent = t;
5950                   t->parent = s;
5951                   if (s)
5952                     {
5953                       if (s->left == p)
5954                         s->left = t;
5955                       else
5956                         s->right = t;
5957                     }
5958                   else
5959                     constructor_pending_elts = t;
5960                 }
5961               break;
5962             }
5963           else
5964             {
5965               /* p->balance == +1; growth of left side balances the node.  */
5966               p->balance = 0;
5967               break;
5968             }
5969         }
5970       else /* r == p->right */
5971         {
5972           if (p->balance == 0)
5973             /* Growth propagation from right side.  */
5974             p->balance++;
5975           else if (p->balance > 0)
5976             {
5977               if (r->balance > 0)
5978                 {
5979                   /* R rotation.  */
5980                   p->right = r->left;
5981                   if (p->right)
5982                     p->right->parent = p;
5983                   r->left = p;
5984
5985                   p->balance = 0;
5986                   r->balance = 0;
5987
5988                   s = p->parent;
5989                   p->parent = r;
5990                   r->parent = s;
5991                   if (s)
5992                     {
5993                       if (s->left == p)
5994                         s->left = r;
5995                       else
5996                         s->right = r;
5997                     }
5998                   else
5999                     constructor_pending_elts = r;
6000                 }
6001               else /* r->balance == -1 */
6002                 {
6003                   /* RL rotation */
6004                   struct init_node *t = r->left;
6005
6006                   r->left = t->right;
6007                   if (r->left)
6008                     r->left->parent = r;
6009                   t->right = r;
6010
6011                   p->right = t->left;
6012                   if (p->right)
6013                     p->right->parent = p;
6014                   t->left = p;
6015
6016                   r->balance = (t->balance < 0);
6017                   p->balance = -(t->balance > 0);
6018                   t->balance = 0;
6019
6020                   s = p->parent;
6021                   p->parent = t;
6022                   r->parent = t;
6023                   t->parent = s;
6024                   if (s)
6025                     {
6026                       if (s->left == p)
6027                         s->left = t;
6028                       else
6029                         s->right = t;
6030                     }
6031                   else
6032                     constructor_pending_elts = t;
6033                 }
6034               break;
6035             }
6036           else
6037             {
6038               /* p->balance == -1; growth of right side balances the node.  */
6039               p->balance = 0;
6040               break;
6041             }
6042         }
6043
6044       r = p;
6045       p = p->parent;
6046     }
6047 }
6048
6049 /* Build AVL tree from a sorted chain.  */
6050
6051 static void
6052 set_nonincremental_init (void)
6053 {
6054   unsigned HOST_WIDE_INT ix;
6055   tree index, value;
6056
6057   if (TREE_CODE (constructor_type) != RECORD_TYPE
6058       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6059     return;
6060
6061   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6062     add_pending_init (index, value);
6063   constructor_elements = 0;
6064   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6065     {
6066       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6067       /* Skip any nameless bit fields at the beginning.  */
6068       while (constructor_unfilled_fields != 0
6069              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6070              && DECL_NAME (constructor_unfilled_fields) == 0)
6071         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6072
6073     }
6074   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6075     {
6076       if (TYPE_DOMAIN (constructor_type))
6077         constructor_unfilled_index
6078             = convert (bitsizetype,
6079                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6080       else
6081         constructor_unfilled_index = bitsize_zero_node;
6082     }
6083   constructor_incremental = 0;
6084 }
6085
6086 /* Build AVL tree from a string constant.  */
6087
6088 static void
6089 set_nonincremental_init_from_string (tree str)
6090 {
6091   tree value, purpose, type;
6092   HOST_WIDE_INT val[2];
6093   const char *p, *end;
6094   int byte, wchar_bytes, charwidth, bitpos;
6095
6096   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6097
6098   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6099       == TYPE_PRECISION (char_type_node))
6100     wchar_bytes = 1;
6101   else
6102     {
6103       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6104                   == TYPE_PRECISION (wchar_type_node));
6105       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6106     }
6107   charwidth = TYPE_PRECISION (char_type_node);
6108   type = TREE_TYPE (constructor_type);
6109   p = TREE_STRING_POINTER (str);
6110   end = p + TREE_STRING_LENGTH (str);
6111
6112   for (purpose = bitsize_zero_node;
6113        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6114        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6115     {
6116       if (wchar_bytes == 1)
6117         {
6118           val[1] = (unsigned char) *p++;
6119           val[0] = 0;
6120         }
6121       else
6122         {
6123           val[0] = 0;
6124           val[1] = 0;
6125           for (byte = 0; byte < wchar_bytes; byte++)
6126             {
6127               if (BYTES_BIG_ENDIAN)
6128                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6129               else
6130                 bitpos = byte * charwidth;
6131               val[bitpos < HOST_BITS_PER_WIDE_INT]
6132                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6133                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6134             }
6135         }
6136
6137       if (!TYPE_UNSIGNED (type))
6138         {
6139           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6140           if (bitpos < HOST_BITS_PER_WIDE_INT)
6141             {
6142               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6143                 {
6144                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6145                   val[0] = -1;
6146                 }
6147             }
6148           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6149             {
6150               if (val[1] < 0)
6151                 val[0] = -1;
6152             }
6153           else if (val[0] & (((HOST_WIDE_INT) 1)
6154                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6155             val[0] |= ((HOST_WIDE_INT) -1)
6156                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6157         }
6158
6159       value = build_int_cst_wide (type, val[1], val[0]);
6160       add_pending_init (purpose, value);
6161     }
6162
6163   constructor_incremental = 0;
6164 }
6165
6166 /* Return value of FIELD in pending initializer or zero if the field was
6167    not initialized yet.  */
6168
6169 static tree
6170 find_init_member (tree field)
6171 {
6172   struct init_node *p;
6173
6174   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6175     {
6176       if (constructor_incremental
6177           && tree_int_cst_lt (field, constructor_unfilled_index))
6178         set_nonincremental_init ();
6179
6180       p = constructor_pending_elts;
6181       while (p)
6182         {
6183           if (tree_int_cst_lt (field, p->purpose))
6184             p = p->left;
6185           else if (tree_int_cst_lt (p->purpose, field))
6186             p = p->right;
6187           else
6188             return p->value;
6189         }
6190     }
6191   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6192     {
6193       tree bitpos = bit_position (field);
6194
6195       if (constructor_incremental
6196           && (!constructor_unfilled_fields
6197               || tree_int_cst_lt (bitpos,
6198                                   bit_position (constructor_unfilled_fields))))
6199         set_nonincremental_init ();
6200
6201       p = constructor_pending_elts;
6202       while (p)
6203         {
6204           if (field == p->purpose)
6205             return p->value;
6206           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6207             p = p->left;
6208           else
6209             p = p->right;
6210         }
6211     }
6212   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6213     {
6214       if (!VEC_empty (constructor_elt, constructor_elements)
6215           && (VEC_last (constructor_elt, constructor_elements)->index
6216               == field))
6217         return VEC_last (constructor_elt, constructor_elements)->value;
6218     }
6219   return 0;
6220 }
6221
6222 /* "Output" the next constructor element.
6223    At top level, really output it to assembler code now.
6224    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6225    TYPE is the data type that the containing data type wants here.
6226    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6227    If VALUE is a string constant, STRICT_STRING is true if it is
6228    unparenthesized or we should not warn here for it being parenthesized.
6229    For other types of VALUE, STRICT_STRING is not used.
6230
6231    PENDING if non-nil means output pending elements that belong
6232    right after this element.  (PENDING is normally 1;
6233    it is 0 while outputting pending elements, to avoid recursion.)  */
6234
6235 static void
6236 output_init_element (tree value, bool strict_string, tree type, tree field,
6237                      int pending)
6238 {
6239   constructor_elt *celt;
6240
6241   if (type == error_mark_node || value == error_mark_node)
6242     {
6243       constructor_erroneous = 1;
6244       return;
6245     }
6246   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6247       && (TREE_CODE (value) == STRING_CST
6248           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6249       && !(TREE_CODE (value) == STRING_CST
6250            && TREE_CODE (type) == ARRAY_TYPE
6251            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6252       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6253                      TYPE_MAIN_VARIANT (type)))
6254     value = array_to_pointer_conversion (value);
6255
6256   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6257       && require_constant_value && !flag_isoc99 && pending)
6258     {
6259       /* As an extension, allow initializing objects with static storage
6260          duration with compound literals (which are then treated just as
6261          the brace enclosed list they contain).  */
6262       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6263       value = DECL_INITIAL (decl);
6264     }
6265
6266   if (value == error_mark_node)
6267     constructor_erroneous = 1;
6268   else if (!TREE_CONSTANT (value))
6269     constructor_constant = 0;
6270   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6271            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6272                 || TREE_CODE (constructor_type) == UNION_TYPE)
6273                && DECL_C_BIT_FIELD (field)
6274                && TREE_CODE (value) != INTEGER_CST))
6275     constructor_simple = 0;
6276
6277   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6278     {
6279       if (require_constant_value)
6280         {
6281           error_init ("initializer element is not constant");
6282           value = error_mark_node;
6283         }
6284       else if (require_constant_elements)
6285         pedwarn ("initializer element is not computable at load time");
6286     }
6287
6288   /* If this field is empty (and not at the end of structure),
6289      don't do anything other than checking the initializer.  */
6290   if (field
6291       && (TREE_TYPE (field) == error_mark_node
6292           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6293               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6294               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6295                   || TREE_CHAIN (field)))))
6296     return;
6297
6298   value = digest_init (type, value, strict_string, require_constant_value);
6299   if (value == error_mark_node)
6300     {
6301       constructor_erroneous = 1;
6302       return;
6303     }
6304
6305   /* If this element doesn't come next in sequence,
6306      put it on constructor_pending_elts.  */
6307   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6308       && (!constructor_incremental
6309           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6310     {
6311       if (constructor_incremental
6312           && tree_int_cst_lt (field, constructor_unfilled_index))
6313         set_nonincremental_init ();
6314
6315       add_pending_init (field, value);
6316       return;
6317     }
6318   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6319            && (!constructor_incremental
6320                || field != constructor_unfilled_fields))
6321     {
6322       /* We do this for records but not for unions.  In a union,
6323          no matter which field is specified, it can be initialized
6324          right away since it starts at the beginning of the union.  */
6325       if (constructor_incremental)
6326         {
6327           if (!constructor_unfilled_fields)
6328             set_nonincremental_init ();
6329           else
6330             {
6331               tree bitpos, unfillpos;
6332
6333               bitpos = bit_position (field);
6334               unfillpos = bit_position (constructor_unfilled_fields);
6335
6336               if (tree_int_cst_lt (bitpos, unfillpos))
6337                 set_nonincremental_init ();
6338             }
6339         }
6340
6341       add_pending_init (field, value);
6342       return;
6343     }
6344   else if (TREE_CODE (constructor_type) == UNION_TYPE
6345            && !VEC_empty (constructor_elt, constructor_elements))
6346     {
6347       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6348                                        constructor_elements)->value))
6349         warning_init (0, "initialized field with side-effects overwritten");
6350       else if (warn_override_init)
6351         warning_init (OPT_Woverride_init, "initialized field overwritten");
6352
6353       /* We can have just one union field set.  */
6354       constructor_elements = 0;
6355     }
6356
6357   /* Otherwise, output this element either to
6358      constructor_elements or to the assembler file.  */
6359
6360   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6361   celt->index = field;
6362   celt->value = value;
6363
6364   /* Advance the variable that indicates sequential elements output.  */
6365   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6366     constructor_unfilled_index
6367       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6368                     bitsize_one_node);
6369   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6370     {
6371       constructor_unfilled_fields
6372         = TREE_CHAIN (constructor_unfilled_fields);
6373
6374       /* Skip any nameless bit fields.  */
6375       while (constructor_unfilled_fields != 0
6376              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6377              && DECL_NAME (constructor_unfilled_fields) == 0)
6378         constructor_unfilled_fields =
6379           TREE_CHAIN (constructor_unfilled_fields);
6380     }
6381   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6382     constructor_unfilled_fields = 0;
6383
6384   /* Now output any pending elements which have become next.  */
6385   if (pending)
6386     output_pending_init_elements (0);
6387 }
6388
6389 /* Output any pending elements which have become next.
6390    As we output elements, constructor_unfilled_{fields,index}
6391    advances, which may cause other elements to become next;
6392    if so, they too are output.
6393
6394    If ALL is 0, we return when there are
6395    no more pending elements to output now.
6396
6397    If ALL is 1, we output space as necessary so that
6398    we can output all the pending elements.  */
6399
6400 static void
6401 output_pending_init_elements (int all)
6402 {
6403   struct init_node *elt = constructor_pending_elts;
6404   tree next;
6405
6406  retry:
6407
6408   /* Look through the whole pending tree.
6409      If we find an element that should be output now,
6410      output it.  Otherwise, set NEXT to the element
6411      that comes first among those still pending.  */
6412
6413   next = 0;
6414   while (elt)
6415     {
6416       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6417         {
6418           if (tree_int_cst_equal (elt->purpose,
6419                                   constructor_unfilled_index))
6420             output_init_element (elt->value, true,
6421                                  TREE_TYPE (constructor_type),
6422                                  constructor_unfilled_index, 0);
6423           else if (tree_int_cst_lt (constructor_unfilled_index,
6424                                     elt->purpose))
6425             {
6426               /* Advance to the next smaller node.  */
6427               if (elt->left)
6428                 elt = elt->left;
6429               else
6430                 {
6431                   /* We have reached the smallest node bigger than the
6432                      current unfilled index.  Fill the space first.  */
6433                   next = elt->purpose;
6434                   break;
6435                 }
6436             }
6437           else
6438             {
6439               /* Advance to the next bigger node.  */
6440               if (elt->right)
6441                 elt = elt->right;
6442               else
6443                 {
6444                   /* We have reached the biggest node in a subtree.  Find
6445                      the parent of it, which is the next bigger node.  */
6446                   while (elt->parent && elt->parent->right == elt)
6447                     elt = elt->parent;
6448                   elt = elt->parent;
6449                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6450                                               elt->purpose))
6451                     {
6452                       next = elt->purpose;
6453                       break;
6454                     }
6455                 }
6456             }
6457         }
6458       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6459                || TREE_CODE (constructor_type) == UNION_TYPE)
6460         {
6461           tree ctor_unfilled_bitpos, elt_bitpos;
6462
6463           /* If the current record is complete we are done.  */
6464           if (constructor_unfilled_fields == 0)
6465             break;
6466
6467           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6468           elt_bitpos = bit_position (elt->purpose);
6469           /* We can't compare fields here because there might be empty
6470              fields in between.  */
6471           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6472             {
6473               constructor_unfilled_fields = elt->purpose;
6474               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6475                                    elt->purpose, 0);
6476             }
6477           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6478             {
6479               /* Advance to the next smaller node.  */
6480               if (elt->left)
6481                 elt = elt->left;
6482               else
6483                 {
6484                   /* We have reached the smallest node bigger than the
6485                      current unfilled field.  Fill the space first.  */
6486                   next = elt->purpose;
6487                   break;
6488                 }
6489             }
6490           else
6491             {
6492               /* Advance to the next bigger node.  */
6493               if (elt->right)
6494                 elt = elt->right;
6495               else
6496                 {
6497                   /* We have reached the biggest node in a subtree.  Find
6498                      the parent of it, which is the next bigger node.  */
6499                   while (elt->parent && elt->parent->right == elt)
6500                     elt = elt->parent;
6501                   elt = elt->parent;
6502                   if (elt
6503                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6504                                            bit_position (elt->purpose))))
6505                     {
6506                       next = elt->purpose;
6507                       break;
6508                     }
6509                 }
6510             }
6511         }
6512     }
6513
6514   /* Ordinarily return, but not if we want to output all
6515      and there are elements left.  */
6516   if (!(all && next != 0))
6517     return;
6518
6519   /* If it's not incremental, just skip over the gap, so that after
6520      jumping to retry we will output the next successive element.  */
6521   if (TREE_CODE (constructor_type) == RECORD_TYPE
6522       || TREE_CODE (constructor_type) == UNION_TYPE)
6523     constructor_unfilled_fields = next;
6524   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6525     constructor_unfilled_index = next;
6526
6527   /* ELT now points to the node in the pending tree with the next
6528      initializer to output.  */
6529   goto retry;
6530 }
6531 \f
6532 /* Add one non-braced element to the current constructor level.
6533    This adjusts the current position within the constructor's type.
6534    This may also start or terminate implicit levels
6535    to handle a partly-braced initializer.
6536
6537    Once this has found the correct level for the new element,
6538    it calls output_init_element.  */
6539
6540 void
6541 process_init_element (struct c_expr value)
6542 {
6543   tree orig_value = value.value;
6544   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6545   bool strict_string = value.original_code == STRING_CST;
6546
6547   designator_depth = 0;
6548   designator_erroneous = 0;
6549
6550   /* Handle superfluous braces around string cst as in
6551      char x[] = {"foo"}; */
6552   if (string_flag
6553       && constructor_type
6554       && TREE_CODE (constructor_type) == ARRAY_TYPE
6555       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6556       && integer_zerop (constructor_unfilled_index))
6557     {
6558       if (constructor_stack->replacement_value.value)
6559         error_init ("excess elements in char array initializer");
6560       constructor_stack->replacement_value = value;
6561       return;
6562     }
6563
6564   if (constructor_stack->replacement_value.value != 0)
6565     {
6566       error_init ("excess elements in struct initializer");
6567       return;
6568     }
6569
6570   /* Ignore elements of a brace group if it is entirely superfluous
6571      and has already been diagnosed.  */
6572   if (constructor_type == 0)
6573     return;
6574
6575   /* If we've exhausted any levels that didn't have braces,
6576      pop them now.  */
6577   while (constructor_stack->implicit)
6578     {
6579       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6580            || TREE_CODE (constructor_type) == UNION_TYPE)
6581           && constructor_fields == 0)
6582         process_init_element (pop_init_level (1));
6583       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6584                && (constructor_max_index == 0
6585                    || tree_int_cst_lt (constructor_max_index,
6586                                        constructor_index)))
6587         process_init_element (pop_init_level (1));
6588       else
6589         break;
6590     }
6591
6592   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6593   if (constructor_range_stack)
6594     {
6595       /* If value is a compound literal and we'll be just using its
6596          content, don't put it into a SAVE_EXPR.  */
6597       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6598           || !require_constant_value
6599           || flag_isoc99)
6600         value.value = save_expr (value.value);
6601     }
6602
6603   while (1)
6604     {
6605       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6606         {
6607           tree fieldtype;
6608           enum tree_code fieldcode;
6609
6610           if (constructor_fields == 0)
6611             {
6612               pedwarn_init ("excess elements in struct initializer");
6613               break;
6614             }
6615
6616           fieldtype = TREE_TYPE (constructor_fields);
6617           if (fieldtype != error_mark_node)
6618             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6619           fieldcode = TREE_CODE (fieldtype);
6620
6621           /* Error for non-static initialization of a flexible array member.  */
6622           if (fieldcode == ARRAY_TYPE
6623               && !require_constant_value
6624               && TYPE_SIZE (fieldtype) == NULL_TREE
6625               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6626             {
6627               error_init ("non-static initialization of a flexible array member");
6628               break;
6629             }
6630
6631           /* Accept a string constant to initialize a subarray.  */
6632           if (value.value != 0
6633               && fieldcode == ARRAY_TYPE
6634               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6635               && string_flag)
6636             value.value = orig_value;
6637           /* Otherwise, if we have come to a subaggregate,
6638              and we don't have an element of its type, push into it.  */
6639           else if (value.value != 0
6640                    && value.value != error_mark_node
6641                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6642                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6643                        || fieldcode == UNION_TYPE))
6644             {
6645               push_init_level (1);
6646               continue;
6647             }
6648
6649           if (value.value)
6650             {
6651               push_member_name (constructor_fields);
6652               output_init_element (value.value, strict_string,
6653                                    fieldtype, constructor_fields, 1);
6654               RESTORE_SPELLING_DEPTH (constructor_depth);
6655             }
6656           else
6657             /* Do the bookkeeping for an element that was
6658                directly output as a constructor.  */
6659             {
6660               /* For a record, keep track of end position of last field.  */
6661               if (DECL_SIZE (constructor_fields))
6662                 constructor_bit_index
6663                   = size_binop (PLUS_EXPR,
6664                                 bit_position (constructor_fields),
6665                                 DECL_SIZE (constructor_fields));
6666
6667               /* If the current field was the first one not yet written out,
6668                  it isn't now, so update.  */
6669               if (constructor_unfilled_fields == constructor_fields)
6670                 {
6671                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6672                   /* Skip any nameless bit fields.  */
6673                   while (constructor_unfilled_fields != 0
6674                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6675                          && DECL_NAME (constructor_unfilled_fields) == 0)
6676                     constructor_unfilled_fields =
6677                       TREE_CHAIN (constructor_unfilled_fields);
6678                 }
6679             }
6680
6681           constructor_fields = TREE_CHAIN (constructor_fields);
6682           /* Skip any nameless bit fields at the beginning.  */
6683           while (constructor_fields != 0
6684                  && DECL_C_BIT_FIELD (constructor_fields)
6685                  && DECL_NAME (constructor_fields) == 0)
6686             constructor_fields = TREE_CHAIN (constructor_fields);
6687         }
6688       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6689         {
6690           tree fieldtype;
6691           enum tree_code fieldcode;
6692
6693           if (constructor_fields == 0)
6694             {
6695               pedwarn_init ("excess elements in union initializer");
6696               break;
6697             }
6698
6699           fieldtype = TREE_TYPE (constructor_fields);
6700           if (fieldtype != error_mark_node)
6701             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6702           fieldcode = TREE_CODE (fieldtype);
6703
6704           /* Warn that traditional C rejects initialization of unions.
6705              We skip the warning if the value is zero.  This is done
6706              under the assumption that the zero initializer in user
6707              code appears conditioned on e.g. __STDC__ to avoid
6708              "missing initializer" warnings and relies on default
6709              initialization to zero in the traditional C case.
6710              We also skip the warning if the initializer is designated,
6711              again on the assumption that this must be conditional on
6712              __STDC__ anyway (and we've already complained about the
6713              member-designator already).  */
6714           if (!in_system_header && !constructor_designated
6715               && !(value.value && (integer_zerop (value.value)
6716                                    || real_zerop (value.value))))
6717             warning (OPT_Wtraditional, "traditional C rejects initialization "
6718                      "of unions");
6719
6720           /* Accept a string constant to initialize a subarray.  */
6721           if (value.value != 0
6722               && fieldcode == ARRAY_TYPE
6723               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6724               && string_flag)
6725             value.value = orig_value;
6726           /* Otherwise, if we have come to a subaggregate,
6727              and we don't have an element of its type, push into it.  */
6728           else if (value.value != 0
6729                    && value.value != error_mark_node
6730                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6731                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6732                        || fieldcode == UNION_TYPE))
6733             {
6734               push_init_level (1);
6735               continue;
6736             }
6737
6738           if (value.value)
6739             {
6740               push_member_name (constructor_fields);
6741               output_init_element (value.value, strict_string,
6742                                    fieldtype, constructor_fields, 1);
6743               RESTORE_SPELLING_DEPTH (constructor_depth);
6744             }
6745           else
6746             /* Do the bookkeeping for an element that was
6747                directly output as a constructor.  */
6748             {
6749               constructor_bit_index = DECL_SIZE (constructor_fields);
6750               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6751             }
6752
6753           constructor_fields = 0;
6754         }
6755       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6756         {
6757           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6758           enum tree_code eltcode = TREE_CODE (elttype);
6759
6760           /* Accept a string constant to initialize a subarray.  */
6761           if (value.value != 0
6762               && eltcode == ARRAY_TYPE
6763               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6764               && string_flag)
6765             value.value = orig_value;
6766           /* Otherwise, if we have come to a subaggregate,
6767              and we don't have an element of its type, push into it.  */
6768           else if (value.value != 0
6769                    && value.value != error_mark_node
6770                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6771                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6772                        || eltcode == UNION_TYPE))
6773             {
6774               push_init_level (1);
6775               continue;
6776             }
6777
6778           if (constructor_max_index != 0
6779               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6780                   || integer_all_onesp (constructor_max_index)))
6781             {
6782               pedwarn_init ("excess elements in array initializer");
6783               break;
6784             }
6785
6786           /* Now output the actual element.  */
6787           if (value.value)
6788             {
6789               push_array_bounds (tree_low_cst (constructor_index, 1));
6790               output_init_element (value.value, strict_string,
6791                                    elttype, constructor_index, 1);
6792               RESTORE_SPELLING_DEPTH (constructor_depth);
6793             }
6794
6795           constructor_index
6796             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6797
6798           if (!value.value)
6799             /* If we are doing the bookkeeping for an element that was
6800                directly output as a constructor, we must update
6801                constructor_unfilled_index.  */
6802             constructor_unfilled_index = constructor_index;
6803         }
6804       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6805         {
6806           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6807
6808          /* Do a basic check of initializer size.  Note that vectors
6809             always have a fixed size derived from their type.  */
6810           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6811             {
6812               pedwarn_init ("excess elements in vector initializer");
6813               break;
6814             }
6815
6816           /* Now output the actual element.  */
6817           if (value.value)
6818             output_init_element (value.value, strict_string,
6819                                  elttype, constructor_index, 1);
6820
6821           constructor_index
6822             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6823
6824           if (!value.value)
6825             /* If we are doing the bookkeeping for an element that was
6826                directly output as a constructor, we must update
6827                constructor_unfilled_index.  */
6828             constructor_unfilled_index = constructor_index;
6829         }
6830
6831       /* Handle the sole element allowed in a braced initializer
6832          for a scalar variable.  */
6833       else if (constructor_type != error_mark_node
6834                && constructor_fields == 0)
6835         {
6836           pedwarn_init ("excess elements in scalar initializer");
6837           break;
6838         }
6839       else
6840         {
6841           if (value.value)
6842             output_init_element (value.value, strict_string,
6843                                  constructor_type, NULL_TREE, 1);
6844           constructor_fields = 0;
6845         }
6846
6847       /* Handle range initializers either at this level or anywhere higher
6848          in the designator stack.  */
6849       if (constructor_range_stack)
6850         {
6851           struct constructor_range_stack *p, *range_stack;
6852           int finish = 0;
6853
6854           range_stack = constructor_range_stack;
6855           constructor_range_stack = 0;
6856           while (constructor_stack != range_stack->stack)
6857             {
6858               gcc_assert (constructor_stack->implicit);
6859               process_init_element (pop_init_level (1));
6860             }
6861           for (p = range_stack;
6862                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6863                p = p->prev)
6864             {
6865               gcc_assert (constructor_stack->implicit);
6866               process_init_element (pop_init_level (1));
6867             }
6868
6869           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6870           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6871             finish = 1;
6872
6873           while (1)
6874             {
6875               constructor_index = p->index;
6876               constructor_fields = p->fields;
6877               if (finish && p->range_end && p->index == p->range_start)
6878                 {
6879                   finish = 0;
6880                   p->prev = 0;
6881                 }
6882               p = p->next;
6883               if (!p)
6884                 break;
6885               push_init_level (2);
6886               p->stack = constructor_stack;
6887               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6888                 p->index = p->range_start;
6889             }
6890
6891           if (!finish)
6892             constructor_range_stack = range_stack;
6893           continue;
6894         }
6895
6896       break;
6897     }
6898
6899   constructor_range_stack = 0;
6900 }
6901 \f
6902 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6903    (guaranteed to be 'volatile' or null) and ARGS (represented using
6904    an ASM_EXPR node).  */
6905 tree
6906 build_asm_stmt (tree cv_qualifier, tree args)
6907 {
6908   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6909     ASM_VOLATILE_P (args) = 1;
6910   return add_stmt (args);
6911 }
6912
6913 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6914    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6915    SIMPLE indicates whether there was anything at all after the
6916    string in the asm expression -- asm("blah") and asm("blah" : )
6917    are subtly different.  We use a ASM_EXPR node to represent this.  */
6918 tree
6919 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6920                 bool simple)
6921 {
6922   tree tail;
6923   tree args;
6924   int i;
6925   const char *constraint;
6926   const char **oconstraints;
6927   bool allows_mem, allows_reg, is_inout;
6928   int ninputs, noutputs;
6929
6930   ninputs = list_length (inputs);
6931   noutputs = list_length (outputs);
6932   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6933
6934   string = resolve_asm_operand_names (string, outputs, inputs);
6935
6936   /* Remove output conversions that change the type but not the mode.  */
6937   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6938     {
6939       tree output = TREE_VALUE (tail);
6940
6941       /* ??? Really, this should not be here.  Users should be using a
6942          proper lvalue, dammit.  But there's a long history of using casts
6943          in the output operands.  In cases like longlong.h, this becomes a
6944          primitive form of typechecking -- if the cast can be removed, then
6945          the output operand had a type of the proper width; otherwise we'll
6946          get an error.  Gross, but ...  */
6947       STRIP_NOPS (output);
6948
6949       if (!lvalue_or_else (output, lv_asm))
6950         output = error_mark_node;
6951
6952       if (output != error_mark_node
6953           && (TREE_READONLY (output)
6954               || TYPE_READONLY (TREE_TYPE (output))
6955               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6956                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6957                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6958         readonly_error (output, lv_asm);
6959
6960       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6961       oconstraints[i] = constraint;
6962
6963       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6964                                    &allows_mem, &allows_reg, &is_inout))
6965         {
6966           /* If the operand is going to end up in memory,
6967              mark it addressable.  */
6968           if (!allows_reg && !c_mark_addressable (output))
6969             output = error_mark_node;
6970         }
6971       else
6972         output = error_mark_node;
6973
6974       TREE_VALUE (tail) = output;
6975     }
6976
6977   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6978     {
6979       tree input;
6980
6981       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6982       input = TREE_VALUE (tail);
6983
6984       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6985                                   oconstraints, &allows_mem, &allows_reg))
6986         {
6987           /* If the operand is going to end up in memory,
6988              mark it addressable.  */
6989           if (!allows_reg && allows_mem)
6990             {
6991               /* Strip the nops as we allow this case.  FIXME, this really
6992                  should be rejected or made deprecated.  */
6993               STRIP_NOPS (input);
6994               if (!c_mark_addressable (input))
6995                 input = error_mark_node;
6996           }
6997         }
6998       else
6999         input = error_mark_node;
7000
7001       TREE_VALUE (tail) = input;
7002     }
7003
7004   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7005
7006   /* asm statements without outputs, including simple ones, are treated
7007      as volatile.  */
7008   ASM_INPUT_P (args) = simple;
7009   ASM_VOLATILE_P (args) = (noutputs == 0);
7010
7011   return args;
7012 }
7013 \f
7014 /* Generate a goto statement to LABEL.  */
7015
7016 tree
7017 c_finish_goto_label (tree label)
7018 {
7019   tree decl = lookup_label (label);
7020   if (!decl)
7021     return NULL_TREE;
7022
7023   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7024     {
7025       error ("jump into statement expression");
7026       return NULL_TREE;
7027     }
7028
7029   if (C_DECL_UNJUMPABLE_VM (decl))
7030     {
7031       error ("jump into scope of identifier with variably modified type");
7032       return NULL_TREE;
7033     }
7034
7035   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7036     {
7037       /* No jump from outside this statement expression context, so
7038          record that there is a jump from within this context.  */
7039       struct c_label_list *nlist;
7040       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7041       nlist->next = label_context_stack_se->labels_used;
7042       nlist->label = decl;
7043       label_context_stack_se->labels_used = nlist;
7044     }
7045
7046   if (!C_DECL_UNDEFINABLE_VM (decl))
7047     {
7048       /* No jump from outside this context context of identifiers with
7049          variably modified type, so record that there is a jump from
7050          within this context.  */
7051       struct c_label_list *nlist;
7052       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7053       nlist->next = label_context_stack_vm->labels_used;
7054       nlist->label = decl;
7055       label_context_stack_vm->labels_used = nlist;
7056     }
7057
7058   TREE_USED (decl) = 1;
7059   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7060 }
7061
7062 /* Generate a computed goto statement to EXPR.  */
7063
7064 tree
7065 c_finish_goto_ptr (tree expr)
7066 {
7067   if (pedantic)
7068     pedwarn ("ISO C forbids %<goto *expr;%>");
7069   expr = convert (ptr_type_node, expr);
7070   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7071 }
7072
7073 /* Generate a C `return' statement.  RETVAL is the expression for what
7074    to return, or a null pointer for `return;' with no value.  */
7075
7076 tree
7077 c_finish_return (tree retval)
7078 {
7079   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7080   bool no_warning = false;
7081
7082   if (TREE_THIS_VOLATILE (current_function_decl))
7083     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7084
7085   if (!retval)
7086     {
7087       current_function_returns_null = 1;
7088       if ((warn_return_type || flag_isoc99)
7089           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7090         {
7091           pedwarn_c99 ("%<return%> with no value, in "
7092                        "function returning non-void");
7093           no_warning = true;
7094         }
7095     }
7096   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7097     {
7098       current_function_returns_null = 1;
7099       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7100         pedwarn ("%<return%> with a value, in function returning void");
7101       else if (pedantic)
7102         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7103     }
7104   else
7105     {
7106       tree t = convert_for_assignment (valtype, retval, ic_return,
7107                                        NULL_TREE, NULL_TREE, 0);
7108       tree res = DECL_RESULT (current_function_decl);
7109       tree inner;
7110
7111       current_function_returns_value = 1;
7112       if (t == error_mark_node)
7113         return NULL_TREE;
7114
7115       inner = t = convert (TREE_TYPE (res), t);
7116
7117       /* Strip any conversions, additions, and subtractions, and see if
7118          we are returning the address of a local variable.  Warn if so.  */
7119       while (1)
7120         {
7121           switch (TREE_CODE (inner))
7122             {
7123             CASE_CONVERT:   case NON_LVALUE_EXPR:
7124             case PLUS_EXPR:
7125               inner = TREE_OPERAND (inner, 0);
7126               continue;
7127
7128             case MINUS_EXPR:
7129               /* If the second operand of the MINUS_EXPR has a pointer
7130                  type (or is converted from it), this may be valid, so
7131                  don't give a warning.  */
7132               {
7133                 tree op1 = TREE_OPERAND (inner, 1);
7134
7135                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7136                        && (CONVERT_EXPR_P (op1)
7137                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7138                   op1 = TREE_OPERAND (op1, 0);
7139
7140                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7141                   break;
7142
7143                 inner = TREE_OPERAND (inner, 0);
7144                 continue;
7145               }
7146
7147             case ADDR_EXPR:
7148               inner = TREE_OPERAND (inner, 0);
7149
7150               while (REFERENCE_CLASS_P (inner)
7151                      && TREE_CODE (inner) != INDIRECT_REF)
7152                 inner = TREE_OPERAND (inner, 0);
7153
7154               if (DECL_P (inner)
7155                   && !DECL_EXTERNAL (inner)
7156                   && !TREE_STATIC (inner)
7157                   && DECL_CONTEXT (inner) == current_function_decl)
7158                 warning (0, "function returns address of local variable");
7159               break;
7160
7161             default:
7162               break;
7163             }
7164
7165           break;
7166         }
7167
7168       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7169     }
7170
7171   ret_stmt = build_stmt (RETURN_EXPR, retval);
7172   TREE_NO_WARNING (ret_stmt) |= no_warning;
7173   return add_stmt (ret_stmt);
7174 }
7175 \f
7176 struct c_switch {
7177   /* The SWITCH_EXPR being built.  */
7178   tree switch_expr;
7179
7180   /* The original type of the testing expression, i.e. before the
7181      default conversion is applied.  */
7182   tree orig_type;
7183
7184   /* A splay-tree mapping the low element of a case range to the high
7185      element, or NULL_TREE if there is no high element.  Used to
7186      determine whether or not a new case label duplicates an old case
7187      label.  We need a tree, rather than simply a hash table, because
7188      of the GNU case range extension.  */
7189   splay_tree cases;
7190
7191   /* Number of nested statement expressions within this switch
7192      statement; if nonzero, case and default labels may not
7193      appear.  */
7194   unsigned int blocked_stmt_expr;
7195
7196   /* Scope of outermost declarations of identifiers with variably
7197      modified type within this switch statement; if nonzero, case and
7198      default labels may not appear.  */
7199   unsigned int blocked_vm;
7200
7201   /* The next node on the stack.  */
7202   struct c_switch *next;
7203 };
7204
7205 /* A stack of the currently active switch statements.  The innermost
7206    switch statement is on the top of the stack.  There is no need to
7207    mark the stack for garbage collection because it is only active
7208    during the processing of the body of a function, and we never
7209    collect at that point.  */
7210
7211 struct c_switch *c_switch_stack;
7212
7213 /* Start a C switch statement, testing expression EXP.  Return the new
7214    SWITCH_EXPR.  */
7215
7216 tree
7217 c_start_case (tree exp)
7218 {
7219   tree orig_type = error_mark_node;
7220   struct c_switch *cs;
7221
7222   if (exp != error_mark_node)
7223     {
7224       orig_type = TREE_TYPE (exp);
7225
7226       if (!INTEGRAL_TYPE_P (orig_type))
7227         {
7228           if (orig_type != error_mark_node)
7229             {
7230               error ("switch quantity not an integer");
7231               orig_type = error_mark_node;
7232             }
7233           exp = integer_zero_node;
7234         }
7235       else
7236         {
7237           tree type = TYPE_MAIN_VARIANT (orig_type);
7238
7239           if (!in_system_header
7240               && (type == long_integer_type_node
7241                   || type == long_unsigned_type_node))
7242             warning (OPT_Wtraditional, "%<long%> switch expression not "
7243                      "converted to %<int%> in ISO C");
7244
7245           exp = default_conversion (exp);
7246         }
7247     }
7248
7249   /* Add this new SWITCH_EXPR to the stack.  */
7250   cs = XNEW (struct c_switch);
7251   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7252   cs->orig_type = orig_type;
7253   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7254   cs->blocked_stmt_expr = 0;
7255   cs->blocked_vm = 0;
7256   cs->next = c_switch_stack;
7257   c_switch_stack = cs;
7258
7259   return add_stmt (cs->switch_expr);
7260 }
7261
7262 /* Process a case label.  */
7263
7264 tree
7265 do_case (tree low_value, tree high_value)
7266 {
7267   tree label = NULL_TREE;
7268
7269   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7270       && !c_switch_stack->blocked_vm)
7271     {
7272       label = c_add_case_label (c_switch_stack->cases,
7273                                 SWITCH_COND (c_switch_stack->switch_expr),
7274                                 c_switch_stack->orig_type,
7275                                 low_value, high_value);
7276       if (label == error_mark_node)
7277         label = NULL_TREE;
7278     }
7279   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7280     {
7281       if (low_value)
7282         error ("case label in statement expression not containing "
7283                "enclosing switch statement");
7284       else
7285         error ("%<default%> label in statement expression not containing "
7286                "enclosing switch statement");
7287     }
7288   else if (c_switch_stack && c_switch_stack->blocked_vm)
7289     {
7290       if (low_value)
7291         error ("case label in scope of identifier with variably modified "
7292                "type not containing enclosing switch statement");
7293       else
7294         error ("%<default%> label in scope of identifier with variably "
7295                "modified type not containing enclosing switch statement");
7296     }
7297   else if (low_value)
7298     error ("case label not within a switch statement");
7299   else
7300     error ("%<default%> label not within a switch statement");
7301
7302   return label;
7303 }
7304
7305 /* Finish the switch statement.  */
7306
7307 void
7308 c_finish_case (tree body)
7309 {
7310   struct c_switch *cs = c_switch_stack;
7311   location_t switch_location;
7312
7313   SWITCH_BODY (cs->switch_expr) = body;
7314
7315   /* We must not be within a statement expression nested in the switch
7316      at this point; we might, however, be within the scope of an
7317      identifier with variably modified type nested in the switch.  */
7318   gcc_assert (!cs->blocked_stmt_expr);
7319
7320   /* Emit warnings as needed.  */
7321   if (EXPR_HAS_LOCATION (cs->switch_expr))
7322     switch_location = EXPR_LOCATION (cs->switch_expr);
7323   else
7324     switch_location = input_location;
7325   c_do_switch_warnings (cs->cases, switch_location,
7326                         TREE_TYPE (cs->switch_expr),
7327                         SWITCH_COND (cs->switch_expr));
7328
7329   /* Pop the stack.  */
7330   c_switch_stack = cs->next;
7331   splay_tree_delete (cs->cases);
7332   XDELETE (cs);
7333 }
7334 \f
7335 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7336    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7337    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7338    statement, and was not surrounded with parenthesis.  */
7339
7340 void
7341 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7342                   tree else_block, bool nested_if)
7343 {
7344   tree stmt;
7345
7346   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7347   if (warn_parentheses && nested_if && else_block == NULL)
7348     {
7349       tree inner_if = then_block;
7350
7351       /* We know from the grammar productions that there is an IF nested
7352          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7353          it might not be exactly THEN_BLOCK, but should be the last
7354          non-container statement within.  */
7355       while (1)
7356         switch (TREE_CODE (inner_if))
7357           {
7358           case COND_EXPR:
7359             goto found;
7360           case BIND_EXPR:
7361             inner_if = BIND_EXPR_BODY (inner_if);
7362             break;
7363           case STATEMENT_LIST:
7364             inner_if = expr_last (then_block);
7365             break;
7366           case TRY_FINALLY_EXPR:
7367           case TRY_CATCH_EXPR:
7368             inner_if = TREE_OPERAND (inner_if, 0);
7369             break;
7370           default:
7371             gcc_unreachable ();
7372           }
7373     found:
7374
7375       if (COND_EXPR_ELSE (inner_if))
7376          warning (OPT_Wparentheses,
7377                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7378                   &if_locus);
7379     }
7380
7381   empty_if_body_warning (then_block, else_block);
7382
7383   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7384   SET_EXPR_LOCATION (stmt, if_locus);
7385   add_stmt (stmt);
7386 }
7387
7388 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7389    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7390    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7391    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7392    the continue label.  Everything is allowed to be NULL.  */
7393
7394 void
7395 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7396                tree blab, tree clab, bool cond_is_first)
7397 {
7398   tree entry = NULL, exit = NULL, t;
7399
7400   /* If the condition is zero don't generate a loop construct.  */
7401   if (cond && integer_zerop (cond))
7402     {
7403       if (cond_is_first)
7404         {
7405           t = build_and_jump (&blab);
7406           SET_EXPR_LOCATION (t, start_locus);
7407           add_stmt (t);
7408         }
7409     }
7410   else
7411     {
7412       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7413
7414       /* If we have an exit condition, then we build an IF with gotos either
7415          out of the loop, or to the top of it.  If there's no exit condition,
7416          then we just build a jump back to the top.  */
7417       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7418
7419       if (cond && !integer_nonzerop (cond))
7420         {
7421           /* Canonicalize the loop condition to the end.  This means
7422              generating a branch to the loop condition.  Reuse the
7423              continue label, if possible.  */
7424           if (cond_is_first)
7425             {
7426               if (incr || !clab)
7427                 {
7428                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7429                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7430                 }
7431               else
7432                 t = build1 (GOTO_EXPR, void_type_node, clab);
7433               SET_EXPR_LOCATION (t, start_locus);
7434               add_stmt (t);
7435             }
7436
7437           t = build_and_jump (&blab);
7438           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7439           if (cond_is_first)
7440             SET_EXPR_LOCATION (exit, start_locus);
7441           else
7442             SET_EXPR_LOCATION (exit, input_location);
7443         }
7444
7445       add_stmt (top);
7446     }
7447
7448   if (body)
7449     add_stmt (body);
7450   if (clab)
7451     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7452   if (incr)
7453     add_stmt (incr);
7454   if (entry)
7455     add_stmt (entry);
7456   if (exit)
7457     add_stmt (exit);
7458   if (blab)
7459     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7460 }
7461
7462 tree
7463 c_finish_bc_stmt (tree *label_p, bool is_break)
7464 {
7465   bool skip;
7466   tree label = *label_p;
7467
7468   /* In switch statements break is sometimes stylistically used after
7469      a return statement.  This can lead to spurious warnings about
7470      control reaching the end of a non-void function when it is
7471      inlined.  Note that we are calling block_may_fallthru with
7472      language specific tree nodes; this works because
7473      block_may_fallthru returns true when given something it does not
7474      understand.  */
7475   skip = !block_may_fallthru (cur_stmt_list);
7476
7477   if (!label)
7478     {
7479       if (!skip)
7480         *label_p = label = create_artificial_label ();
7481     }
7482   else if (TREE_CODE (label) == LABEL_DECL)
7483     ;
7484   else switch (TREE_INT_CST_LOW (label))
7485     {
7486     case 0:
7487       if (is_break)
7488         error ("break statement not within loop or switch");
7489       else
7490         error ("continue statement not within a loop");
7491       return NULL_TREE;
7492
7493     case 1:
7494       gcc_assert (is_break);
7495       error ("break statement used with OpenMP for loop");
7496       return NULL_TREE;
7497
7498     default:
7499       gcc_unreachable ();
7500     }
7501
7502   if (skip)
7503     return NULL_TREE;
7504
7505   if (!is_break)
7506     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7507
7508   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7509 }
7510
7511 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7512
7513 static void
7514 emit_side_effect_warnings (tree expr)
7515 {
7516   if (expr == error_mark_node)
7517     ;
7518   else if (!TREE_SIDE_EFFECTS (expr))
7519     {
7520       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7521         warning (OPT_Wunused_value, "%Hstatement with no effect",
7522                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7523     }
7524   else
7525     warn_if_unused_value (expr, input_location);
7526 }
7527
7528 /* Process an expression as if it were a complete statement.  Emit
7529    diagnostics, but do not call ADD_STMT.  */
7530
7531 tree
7532 c_process_expr_stmt (tree expr)
7533 {
7534   if (!expr)
7535     return NULL_TREE;
7536
7537   if (warn_sequence_point)
7538     verify_sequence_points (expr);
7539
7540   if (TREE_TYPE (expr) != error_mark_node
7541       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7542       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7543     error ("expression statement has incomplete type");
7544
7545   /* If we're not processing a statement expression, warn about unused values.
7546      Warnings for statement expressions will be emitted later, once we figure
7547      out which is the result.  */
7548   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7549       && warn_unused_value)
7550     emit_side_effect_warnings (expr);
7551
7552   /* If the expression is not of a type to which we cannot assign a line
7553      number, wrap the thing in a no-op NOP_EXPR.  */
7554   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7555     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7556
7557   if (CAN_HAVE_LOCATION_P (expr))
7558     SET_EXPR_LOCATION (expr, input_location);
7559
7560   return expr;
7561 }
7562
7563 /* Emit an expression as a statement.  */
7564
7565 tree
7566 c_finish_expr_stmt (tree expr)
7567 {
7568   if (expr)
7569     return add_stmt (c_process_expr_stmt (expr));
7570   else
7571     return NULL;
7572 }
7573
7574 /* Do the opposite and emit a statement as an expression.  To begin,
7575    create a new binding level and return it.  */
7576
7577 tree
7578 c_begin_stmt_expr (void)
7579 {
7580   tree ret;
7581   struct c_label_context_se *nstack;
7582   struct c_label_list *glist;
7583
7584   /* We must force a BLOCK for this level so that, if it is not expanded
7585      later, there is a way to turn off the entire subtree of blocks that
7586      are contained in it.  */
7587   keep_next_level ();
7588   ret = c_begin_compound_stmt (true);
7589   if (c_switch_stack)
7590     {
7591       c_switch_stack->blocked_stmt_expr++;
7592       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7593     }
7594   for (glist = label_context_stack_se->labels_used;
7595        glist != NULL;
7596        glist = glist->next)
7597     {
7598       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7599     }
7600   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7601   nstack->labels_def = NULL;
7602   nstack->labels_used = NULL;
7603   nstack->next = label_context_stack_se;
7604   label_context_stack_se = nstack;
7605
7606   /* Mark the current statement list as belonging to a statement list.  */
7607   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7608
7609   return ret;
7610 }
7611
7612 tree
7613 c_finish_stmt_expr (tree body)
7614 {
7615   tree last, type, tmp, val;
7616   tree *last_p;
7617   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7618
7619   body = c_end_compound_stmt (body, true);
7620   if (c_switch_stack)
7621     {
7622       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7623       c_switch_stack->blocked_stmt_expr--;
7624     }
7625   /* It is no longer possible to jump to labels defined within this
7626      statement expression.  */
7627   for (dlist = label_context_stack_se->labels_def;
7628        dlist != NULL;
7629        dlist = dlist->next)
7630     {
7631       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7632     }
7633   /* It is again possible to define labels with a goto just outside
7634      this statement expression.  */
7635   for (glist = label_context_stack_se->next->labels_used;
7636        glist != NULL;
7637        glist = glist->next)
7638     {
7639       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7640       glist_prev = glist;
7641     }
7642   if (glist_prev != NULL)
7643     glist_prev->next = label_context_stack_se->labels_used;
7644   else
7645     label_context_stack_se->next->labels_used
7646       = label_context_stack_se->labels_used;
7647   label_context_stack_se = label_context_stack_se->next;
7648
7649   /* Locate the last statement in BODY.  See c_end_compound_stmt
7650      about always returning a BIND_EXPR.  */
7651   last_p = &BIND_EXPR_BODY (body);
7652   last = BIND_EXPR_BODY (body);
7653
7654  continue_searching:
7655   if (TREE_CODE (last) == STATEMENT_LIST)
7656     {
7657       tree_stmt_iterator i;
7658
7659       /* This can happen with degenerate cases like ({ }).  No value.  */
7660       if (!TREE_SIDE_EFFECTS (last))
7661         return body;
7662
7663       /* If we're supposed to generate side effects warnings, process
7664          all of the statements except the last.  */
7665       if (warn_unused_value)
7666         {
7667           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7668             emit_side_effect_warnings (tsi_stmt (i));
7669         }
7670       else
7671         i = tsi_last (last);
7672       last_p = tsi_stmt_ptr (i);
7673       last = *last_p;
7674     }
7675
7676   /* If the end of the list is exception related, then the list was split
7677      by a call to push_cleanup.  Continue searching.  */
7678   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7679       || TREE_CODE (last) == TRY_CATCH_EXPR)
7680     {
7681       last_p = &TREE_OPERAND (last, 0);
7682       last = *last_p;
7683       goto continue_searching;
7684     }
7685
7686   /* In the case that the BIND_EXPR is not necessary, return the
7687      expression out from inside it.  */
7688   if (last == error_mark_node
7689       || (last == BIND_EXPR_BODY (body)
7690           && BIND_EXPR_VARS (body) == NULL))
7691     {
7692       /* Do not warn if the return value of a statement expression is
7693          unused.  */
7694       if (CAN_HAVE_LOCATION_P (last))
7695         TREE_NO_WARNING (last) = 1;
7696       return last;
7697     }
7698
7699   /* Extract the type of said expression.  */
7700   type = TREE_TYPE (last);
7701
7702   /* If we're not returning a value at all, then the BIND_EXPR that
7703      we already have is a fine expression to return.  */
7704   if (!type || VOID_TYPE_P (type))
7705     return body;
7706
7707   /* Now that we've located the expression containing the value, it seems
7708      silly to make voidify_wrapper_expr repeat the process.  Create a
7709      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7710   tmp = create_tmp_var_raw (type, NULL);
7711
7712   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7713      tree_expr_nonnegative_p giving up immediately.  */
7714   val = last;
7715   if (TREE_CODE (val) == NOP_EXPR
7716       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7717     val = TREE_OPERAND (val, 0);
7718
7719   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7720   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7721
7722   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7723 }
7724
7725 /* Begin the scope of an identifier of variably modified type, scope
7726    number SCOPE.  Jumping from outside this scope to inside it is not
7727    permitted.  */
7728
7729 void
7730 c_begin_vm_scope (unsigned int scope)
7731 {
7732   struct c_label_context_vm *nstack;
7733   struct c_label_list *glist;
7734
7735   gcc_assert (scope > 0);
7736
7737   /* At file_scope, we don't have to do any processing.  */
7738   if (label_context_stack_vm == NULL)
7739     return;
7740
7741   if (c_switch_stack && !c_switch_stack->blocked_vm)
7742     c_switch_stack->blocked_vm = scope;
7743   for (glist = label_context_stack_vm->labels_used;
7744        glist != NULL;
7745        glist = glist->next)
7746     {
7747       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7748     }
7749   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7750   nstack->labels_def = NULL;
7751   nstack->labels_used = NULL;
7752   nstack->scope = scope;
7753   nstack->next = label_context_stack_vm;
7754   label_context_stack_vm = nstack;
7755 }
7756
7757 /* End a scope which may contain identifiers of variably modified
7758    type, scope number SCOPE.  */
7759
7760 void
7761 c_end_vm_scope (unsigned int scope)
7762 {
7763   if (label_context_stack_vm == NULL)
7764     return;
7765   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7766     c_switch_stack->blocked_vm = 0;
7767   /* We may have a number of nested scopes of identifiers with
7768      variably modified type, all at this depth.  Pop each in turn.  */
7769   while (label_context_stack_vm->scope == scope)
7770     {
7771       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7772
7773       /* It is no longer possible to jump to labels defined within this
7774          scope.  */
7775       for (dlist = label_context_stack_vm->labels_def;
7776            dlist != NULL;
7777            dlist = dlist->next)
7778         {
7779           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7780         }
7781       /* It is again possible to define labels with a goto just outside
7782          this scope.  */
7783       for (glist = label_context_stack_vm->next->labels_used;
7784            glist != NULL;
7785            glist = glist->next)
7786         {
7787           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7788           glist_prev = glist;
7789         }
7790       if (glist_prev != NULL)
7791         glist_prev->next = label_context_stack_vm->labels_used;
7792       else
7793         label_context_stack_vm->next->labels_used
7794           = label_context_stack_vm->labels_used;
7795       label_context_stack_vm = label_context_stack_vm->next;
7796     }
7797 }
7798 \f
7799 /* Begin and end compound statements.  This is as simple as pushing
7800    and popping new statement lists from the tree.  */
7801
7802 tree
7803 c_begin_compound_stmt (bool do_scope)
7804 {
7805   tree stmt = push_stmt_list ();
7806   if (do_scope)
7807     push_scope ();
7808   return stmt;
7809 }
7810
7811 tree
7812 c_end_compound_stmt (tree stmt, bool do_scope)
7813 {
7814   tree block = NULL;
7815
7816   if (do_scope)
7817     {
7818       if (c_dialect_objc ())
7819         objc_clear_super_receiver ();
7820       block = pop_scope ();
7821     }
7822
7823   stmt = pop_stmt_list (stmt);
7824   stmt = c_build_bind_expr (block, stmt);
7825
7826   /* If this compound statement is nested immediately inside a statement
7827      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7828      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7829      STATEMENT_LISTs merge, and thus we can lose track of what statement
7830      was really last.  */
7831   if (cur_stmt_list
7832       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7833       && TREE_CODE (stmt) != BIND_EXPR)
7834     {
7835       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7836       TREE_SIDE_EFFECTS (stmt) = 1;
7837     }
7838
7839   return stmt;
7840 }
7841
7842 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7843    when the current scope is exited.  EH_ONLY is true when this is not
7844    meant to apply to normal control flow transfer.  */
7845
7846 void
7847 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7848 {
7849   enum tree_code code;
7850   tree stmt, list;
7851   bool stmt_expr;
7852
7853   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7854   stmt = build_stmt (code, NULL, cleanup);
7855   add_stmt (stmt);
7856   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7857   list = push_stmt_list ();
7858   TREE_OPERAND (stmt, 0) = list;
7859   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7860 }
7861 \f
7862 /* Build a binary-operation expression without default conversions.
7863    CODE is the kind of expression to build.
7864    This function differs from `build' in several ways:
7865    the data type of the result is computed and recorded in it,
7866    warnings are generated if arg data types are invalid,
7867    special handling for addition and subtraction of pointers is known,
7868    and some optimization is done (operations on narrow ints
7869    are done in the narrower type when that gives the same result).
7870    Constant folding is also done before the result is returned.
7871
7872    Note that the operands will never have enumeral types, or function
7873    or array types, because either they will have the default conversions
7874    performed or they have both just been converted to some other type in which
7875    the arithmetic is to be done.  */
7876
7877 tree
7878 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7879                  int convert_p)
7880 {
7881   tree type0, type1;
7882   enum tree_code code0, code1;
7883   tree op0, op1;
7884   const char *invalid_op_diag;
7885
7886   /* Expression code to give to the expression when it is built.
7887      Normally this is CODE, which is what the caller asked for,
7888      but in some special cases we change it.  */
7889   enum tree_code resultcode = code;
7890
7891   /* Data type in which the computation is to be performed.
7892      In the simplest cases this is the common type of the arguments.  */
7893   tree result_type = NULL;
7894
7895   /* Nonzero means operands have already been type-converted
7896      in whatever way is necessary.
7897      Zero means they need to be converted to RESULT_TYPE.  */
7898   int converted = 0;
7899
7900   /* Nonzero means create the expression with this type, rather than
7901      RESULT_TYPE.  */
7902   tree build_type = 0;
7903
7904   /* Nonzero means after finally constructing the expression
7905      convert it to this type.  */
7906   tree final_type = 0;
7907
7908   /* Nonzero if this is an operation like MIN or MAX which can
7909      safely be computed in short if both args are promoted shorts.
7910      Also implies COMMON.
7911      -1 indicates a bitwise operation; this makes a difference
7912      in the exact conditions for when it is safe to do the operation
7913      in a narrower mode.  */
7914   int shorten = 0;
7915
7916   /* Nonzero if this is a comparison operation;
7917      if both args are promoted shorts, compare the original shorts.
7918      Also implies COMMON.  */
7919   int short_compare = 0;
7920
7921   /* Nonzero if this is a right-shift operation, which can be computed on the
7922      original short and then promoted if the operand is a promoted short.  */
7923   int short_shift = 0;
7924
7925   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7926   int common = 0;
7927
7928   /* True means types are compatible as far as ObjC is concerned.  */
7929   bool objc_ok;
7930
7931   if (convert_p)
7932     {
7933       op0 = default_conversion (orig_op0);
7934       op1 = default_conversion (orig_op1);
7935     }
7936   else
7937     {
7938       op0 = orig_op0;
7939       op1 = orig_op1;
7940     }
7941
7942   type0 = TREE_TYPE (op0);
7943   type1 = TREE_TYPE (op1);
7944
7945   /* The expression codes of the data types of the arguments tell us
7946      whether the arguments are integers, floating, pointers, etc.  */
7947   code0 = TREE_CODE (type0);
7948   code1 = TREE_CODE (type1);
7949
7950   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7951   STRIP_TYPE_NOPS (op0);
7952   STRIP_TYPE_NOPS (op1);
7953
7954   /* If an error was already reported for one of the arguments,
7955      avoid reporting another error.  */
7956
7957   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7958     return error_mark_node;
7959
7960   if ((invalid_op_diag
7961        = targetm.invalid_binary_op (code, type0, type1)))
7962     {
7963       error (invalid_op_diag);
7964       return error_mark_node;
7965     }
7966
7967   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7968
7969   switch (code)
7970     {
7971     case PLUS_EXPR:
7972       /* Handle the pointer + int case.  */
7973       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7974         return pointer_int_sum (PLUS_EXPR, op0, op1);
7975       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7976         return pointer_int_sum (PLUS_EXPR, op1, op0);
7977       else
7978         common = 1;
7979       break;
7980
7981     case MINUS_EXPR:
7982       /* Subtraction of two similar pointers.
7983          We must subtract them as integers, then divide by object size.  */
7984       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7985           && comp_target_types (type0, type1))
7986         return pointer_diff (op0, op1);
7987       /* Handle pointer minus int.  Just like pointer plus int.  */
7988       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7989         return pointer_int_sum (MINUS_EXPR, op0, op1);
7990       else
7991         common = 1;
7992       break;
7993
7994     case MULT_EXPR:
7995       common = 1;
7996       break;
7997
7998     case TRUNC_DIV_EXPR:
7999     case CEIL_DIV_EXPR:
8000     case FLOOR_DIV_EXPR:
8001     case ROUND_DIV_EXPR:
8002     case EXACT_DIV_EXPR:
8003       warn_for_div_by_zero (op1);
8004
8005       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8006            || code0 == FIXED_POINT_TYPE
8007            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8008           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8009               || code1 == FIXED_POINT_TYPE
8010               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8011         {
8012           enum tree_code tcode0 = code0, tcode1 = code1;
8013
8014           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8015             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8016           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8017             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8018
8019           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8020               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8021             resultcode = RDIV_EXPR;
8022           else
8023             /* Although it would be tempting to shorten always here, that
8024                loses on some targets, since the modulo instruction is
8025                undefined if the quotient can't be represented in the
8026                computation mode.  We shorten only if unsigned or if
8027                dividing by something we know != -1.  */
8028             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8029                        || (TREE_CODE (op1) == INTEGER_CST
8030                            && !integer_all_onesp (op1)));
8031           common = 1;
8032         }
8033       break;
8034
8035     case BIT_AND_EXPR:
8036     case BIT_IOR_EXPR:
8037     case BIT_XOR_EXPR:
8038       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8039         shorten = -1;
8040       /* Allow vector types which are not floating point types.   */
8041       else if (code0 == VECTOR_TYPE
8042                && code1 == VECTOR_TYPE
8043                && !VECTOR_FLOAT_TYPE_P (type0)
8044                && !VECTOR_FLOAT_TYPE_P (type1))
8045         common = 1;
8046       break;
8047
8048     case TRUNC_MOD_EXPR:
8049     case FLOOR_MOD_EXPR:
8050       warn_for_div_by_zero (op1);
8051
8052       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8053         {
8054           /* Although it would be tempting to shorten always here, that loses
8055              on some targets, since the modulo instruction is undefined if the
8056              quotient can't be represented in the computation mode.  We shorten
8057              only if unsigned or if dividing by something we know != -1.  */
8058           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8059                      || (TREE_CODE (op1) == INTEGER_CST
8060                          && !integer_all_onesp (op1)));
8061           common = 1;
8062         }
8063       break;
8064
8065     case TRUTH_ANDIF_EXPR:
8066     case TRUTH_ORIF_EXPR:
8067     case TRUTH_AND_EXPR:
8068     case TRUTH_OR_EXPR:
8069     case TRUTH_XOR_EXPR:
8070       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8071            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8072            || code0 == FIXED_POINT_TYPE)
8073           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8074               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8075               || code1 == FIXED_POINT_TYPE))
8076         {
8077           /* Result of these operations is always an int,
8078              but that does not mean the operands should be
8079              converted to ints!  */
8080           result_type = integer_type_node;
8081           op0 = c_common_truthvalue_conversion (op0);
8082           op1 = c_common_truthvalue_conversion (op1);
8083           converted = 1;
8084         }
8085       break;
8086
8087       /* Shift operations: result has same type as first operand;
8088          always convert second operand to int.
8089          Also set SHORT_SHIFT if shifting rightward.  */
8090
8091     case RSHIFT_EXPR:
8092       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8093           && code1 == INTEGER_TYPE)
8094         {
8095           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8096             {
8097               if (tree_int_cst_sgn (op1) < 0)
8098                 warning (0, "right shift count is negative");
8099               else
8100                 {
8101                   if (!integer_zerop (op1))
8102                     short_shift = 1;
8103
8104                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8105                     warning (0, "right shift count >= width of type");
8106                 }
8107             }
8108
8109           /* Use the type of the value to be shifted.  */
8110           result_type = type0;
8111           /* Convert the shift-count to an integer, regardless of size
8112              of value being shifted.  */
8113           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8114             op1 = convert (integer_type_node, op1);
8115           /* Avoid converting op1 to result_type later.  */
8116           converted = 1;
8117         }
8118       break;
8119
8120     case LSHIFT_EXPR:
8121       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8122           && code1 == INTEGER_TYPE)
8123         {
8124           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8125             {
8126               if (tree_int_cst_sgn (op1) < 0)
8127                 warning (0, "left shift count is negative");
8128
8129               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8130                 warning (0, "left shift count >= width of type");
8131             }
8132
8133           /* Use the type of the value to be shifted.  */
8134           result_type = type0;
8135           /* Convert the shift-count to an integer, regardless of size
8136              of value being shifted.  */
8137           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8138             op1 = convert (integer_type_node, op1);
8139           /* Avoid converting op1 to result_type later.  */
8140           converted = 1;
8141         }
8142       break;
8143
8144     case EQ_EXPR:
8145     case NE_EXPR:
8146       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8147         warning (OPT_Wfloat_equal,
8148                  "comparing floating point with == or != is unsafe");
8149       /* Result of comparison is always int,
8150          but don't convert the args to int!  */
8151       build_type = integer_type_node;
8152       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8153            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8154           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8155               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8156         short_compare = 1;
8157       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8158         {
8159           tree tt0 = TREE_TYPE (type0);
8160           tree tt1 = TREE_TYPE (type1);
8161           /* Anything compares with void *.  void * compares with anything.
8162              Otherwise, the targets must be compatible
8163              and both must be object or both incomplete.  */
8164           if (comp_target_types (type0, type1))
8165             result_type = common_pointer_type (type0, type1);
8166           else if (VOID_TYPE_P (tt0))
8167             {
8168               /* op0 != orig_op0 detects the case of something
8169                  whose value is 0 but which isn't a valid null ptr const.  */
8170               if (pedantic && !null_pointer_constant_p (orig_op0)
8171                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8172                 pedwarn ("ISO C forbids comparison of %<void *%>"
8173                          " with function pointer");
8174             }
8175           else if (VOID_TYPE_P (tt1))
8176             {
8177               if (pedantic && !null_pointer_constant_p (orig_op1)
8178                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8179                 pedwarn ("ISO C forbids comparison of %<void *%>"
8180                          " with function pointer");
8181             }
8182           else
8183             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8184             if (!objc_ok)
8185               pedwarn ("comparison of distinct pointer types lacks a cast");
8186
8187           if (result_type == NULL_TREE)
8188             result_type = ptr_type_node;
8189         }
8190       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8191         {
8192           if (TREE_CODE (op0) == ADDR_EXPR
8193               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8194             warning (OPT_Waddress, "the address of %qD will never be NULL",
8195                      TREE_OPERAND (op0, 0));
8196           result_type = type0;
8197         }
8198       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8199         {
8200           if (TREE_CODE (op1) == ADDR_EXPR
8201               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8202             warning (OPT_Waddress, "the address of %qD will never be NULL",
8203                      TREE_OPERAND (op1, 0));
8204           result_type = type1;
8205         }
8206       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8207         {
8208           result_type = type0;
8209           pedwarn ("comparison between pointer and integer");
8210         }
8211       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8212         {
8213           result_type = type1;
8214           pedwarn ("comparison between pointer and integer");
8215         }
8216       break;
8217
8218     case LE_EXPR:
8219     case GE_EXPR:
8220     case LT_EXPR:
8221     case GT_EXPR:
8222       build_type = integer_type_node;
8223       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8224            || code0 == FIXED_POINT_TYPE)
8225           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8226               || code1 == FIXED_POINT_TYPE))
8227         short_compare = 1;
8228       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8229         {
8230           if (comp_target_types (type0, type1))
8231             {
8232               result_type = common_pointer_type (type0, type1);
8233               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8234                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8235                 pedwarn ("comparison of complete and incomplete pointers");
8236               else if (pedantic
8237                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8238                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8239             }
8240           else
8241             {
8242               result_type = ptr_type_node;
8243               pedwarn ("comparison of distinct pointer types lacks a cast");
8244             }
8245         }
8246       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8247         {
8248           result_type = type0;
8249           if (pedantic || extra_warnings)
8250             pedwarn ("ordered comparison of pointer with integer zero");
8251         }
8252       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8253         {
8254           result_type = type1;
8255           if (pedantic)
8256             pedwarn ("ordered comparison of pointer with integer zero");
8257         }
8258       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8259         {
8260           result_type = type0;
8261           pedwarn ("comparison between pointer and integer");
8262         }
8263       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8264         {
8265           result_type = type1;
8266           pedwarn ("comparison between pointer and integer");
8267         }
8268       break;
8269
8270     default:
8271       gcc_unreachable ();
8272     }
8273
8274   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8275     return error_mark_node;
8276
8277   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8278       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8279           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8280                                                     TREE_TYPE (type1))))
8281     {
8282       binary_op_error (code, type0, type1);
8283       return error_mark_node;
8284     }
8285
8286   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8287        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8288       &&
8289       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8290        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8291     {
8292       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8293
8294       if (shorten || common || short_compare)
8295         {
8296           result_type = c_common_type (type0, type1);
8297           if (result_type == error_mark_node)
8298             return error_mark_node;
8299         }
8300
8301       /* For certain operations (which identify themselves by shorten != 0)
8302          if both args were extended from the same smaller type,
8303          do the arithmetic in that type and then extend.
8304
8305          shorten !=0 and !=1 indicates a bitwise operation.
8306          For them, this optimization is safe only if
8307          both args are zero-extended or both are sign-extended.
8308          Otherwise, we might change the result.
8309          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8310          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8311
8312       if (shorten && none_complex)
8313         {
8314           int unsigned0, unsigned1;
8315           tree arg0, arg1;
8316           int uns;
8317           tree type;
8318
8319           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8320              excessive narrowing when we call get_narrower below.  For
8321              example, suppose that OP0 is of unsigned int extended
8322              from signed char and that RESULT_TYPE is long long int.
8323              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8324              like
8325
8326                (long long int) (unsigned int) signed_char
8327
8328              which get_narrower would narrow down to
8329
8330                (unsigned int) signed char
8331
8332              If we do not cast OP0 first, get_narrower would return
8333              signed_char, which is inconsistent with the case of the
8334              explicit cast.  */
8335           op0 = convert (result_type, op0);
8336           op1 = convert (result_type, op1);
8337
8338           arg0 = get_narrower (op0, &unsigned0);
8339           arg1 = get_narrower (op1, &unsigned1);
8340
8341           /* UNS is 1 if the operation to be done is an unsigned one.  */
8342           uns = TYPE_UNSIGNED (result_type);
8343
8344           final_type = result_type;
8345
8346           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8347              but it *requires* conversion to FINAL_TYPE.  */
8348
8349           if ((TYPE_PRECISION (TREE_TYPE (op0))
8350                == TYPE_PRECISION (TREE_TYPE (arg0)))
8351               && TREE_TYPE (op0) != final_type)
8352             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8353           if ((TYPE_PRECISION (TREE_TYPE (op1))
8354                == TYPE_PRECISION (TREE_TYPE (arg1)))
8355               && TREE_TYPE (op1) != final_type)
8356             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8357
8358           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8359
8360           /* For bitwise operations, signedness of nominal type
8361              does not matter.  Consider only how operands were extended.  */
8362           if (shorten == -1)
8363             uns = unsigned0;
8364
8365           /* Note that in all three cases below we refrain from optimizing
8366              an unsigned operation on sign-extended args.
8367              That would not be valid.  */
8368
8369           /* Both args variable: if both extended in same way
8370              from same width, do it in that width.
8371              Do it unsigned if args were zero-extended.  */
8372           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8373                < TYPE_PRECISION (result_type))
8374               && (TYPE_PRECISION (TREE_TYPE (arg1))
8375                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8376               && unsigned0 == unsigned1
8377               && (unsigned0 || !uns))
8378             result_type
8379               = c_common_signed_or_unsigned_type
8380               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8381           else if (TREE_CODE (arg0) == INTEGER_CST
8382                    && (unsigned1 || !uns)
8383                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8384                        < TYPE_PRECISION (result_type))
8385                    && (type
8386                        = c_common_signed_or_unsigned_type (unsigned1,
8387                                                            TREE_TYPE (arg1)))
8388                    && !POINTER_TYPE_P (type)
8389                    && int_fits_type_p (arg0, type))
8390             result_type = type;
8391           else if (TREE_CODE (arg1) == INTEGER_CST
8392                    && (unsigned0 || !uns)
8393                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8394                        < TYPE_PRECISION (result_type))
8395                    && (type
8396                        = c_common_signed_or_unsigned_type (unsigned0,
8397                                                            TREE_TYPE (arg0)))
8398                    && !POINTER_TYPE_P (type)
8399                    && int_fits_type_p (arg1, type))
8400             result_type = type;
8401         }
8402
8403       /* Shifts can be shortened if shifting right.  */
8404
8405       if (short_shift)
8406         {
8407           int unsigned_arg;
8408           tree arg0 = get_narrower (op0, &unsigned_arg);
8409
8410           final_type = result_type;
8411
8412           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8413             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8414
8415           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8416               /* We can shorten only if the shift count is less than the
8417                  number of bits in the smaller type size.  */
8418               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8419               /* We cannot drop an unsigned shift after sign-extension.  */
8420               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8421             {
8422               /* Do an unsigned shift if the operand was zero-extended.  */
8423               result_type
8424                 = c_common_signed_or_unsigned_type (unsigned_arg,
8425                                                     TREE_TYPE (arg0));
8426               /* Convert value-to-be-shifted to that type.  */
8427               if (TREE_TYPE (op0) != result_type)
8428                 op0 = convert (result_type, op0);
8429               converted = 1;
8430             }
8431         }
8432
8433       /* Comparison operations are shortened too but differently.
8434          They identify themselves by setting short_compare = 1.  */
8435
8436       if (short_compare)
8437         {
8438           /* Don't write &op0, etc., because that would prevent op0
8439              from being kept in a register.
8440              Instead, make copies of the our local variables and
8441              pass the copies by reference, then copy them back afterward.  */
8442           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8443           enum tree_code xresultcode = resultcode;
8444           tree val
8445             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8446
8447           if (val != 0)
8448             return val;
8449
8450           op0 = xop0, op1 = xop1;
8451           converted = 1;
8452           resultcode = xresultcode;
8453
8454           if (warn_sign_compare && skip_evaluation == 0)
8455             {
8456               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8457               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8458               int unsignedp0, unsignedp1;
8459               tree primop0 = get_narrower (op0, &unsignedp0);
8460               tree primop1 = get_narrower (op1, &unsignedp1);
8461
8462               xop0 = orig_op0;
8463               xop1 = orig_op1;
8464               STRIP_TYPE_NOPS (xop0);
8465               STRIP_TYPE_NOPS (xop1);
8466
8467               /* Give warnings for comparisons between signed and unsigned
8468                  quantities that may fail.
8469
8470                  Do the checking based on the original operand trees, so that
8471                  casts will be considered, but default promotions won't be.
8472
8473                  Do not warn if the comparison is being done in a signed type,
8474                  since the signed type will only be chosen if it can represent
8475                  all the values of the unsigned type.  */
8476               if (!TYPE_UNSIGNED (result_type))
8477                 /* OK */;
8478               /* Do not warn if both operands are the same signedness.  */
8479               else if (op0_signed == op1_signed)
8480                 /* OK */;
8481               else
8482                 {
8483                   tree sop, uop;
8484                   bool ovf;
8485
8486                   if (op0_signed)
8487                     sop = xop0, uop = xop1;
8488                   else
8489                     sop = xop1, uop = xop0;
8490
8491                   /* Do not warn if the signed quantity is an
8492                      unsuffixed integer literal (or some static
8493                      constant expression involving such literals or a
8494                      conditional expression involving such literals)
8495                      and it is non-negative.  */
8496                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8497                     /* OK */;
8498                   /* Do not warn if the comparison is an equality operation,
8499                      the unsigned quantity is an integral constant, and it
8500                      would fit in the result if the result were signed.  */
8501                   else if (TREE_CODE (uop) == INTEGER_CST
8502                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8503                            && int_fits_type_p
8504                            (uop, c_common_signed_type (result_type)))
8505                     /* OK */;
8506                   /* Do not warn if the unsigned quantity is an enumeration
8507                      constant and its maximum value would fit in the result
8508                      if the result were signed.  */
8509                   else if (TREE_CODE (uop) == INTEGER_CST
8510                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8511                            && int_fits_type_p
8512                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8513                             c_common_signed_type (result_type)))
8514                     /* OK */;
8515                   else
8516                     warning (OPT_Wsign_compare, "comparison between signed and unsigned");
8517                 }
8518
8519               /* Warn if two unsigned values are being compared in a size
8520                  larger than their original size, and one (and only one) is the
8521                  result of a `~' operator.  This comparison will always fail.
8522
8523                  Also warn if one operand is a constant, and the constant
8524                  does not have all bits set that are set in the ~ operand
8525                  when it is extended.  */
8526
8527               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8528                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8529                 {
8530                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8531                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8532                                             &unsignedp0);
8533                   else
8534                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8535                                             &unsignedp1);
8536
8537                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8538                     {
8539                       tree primop;
8540                       HOST_WIDE_INT constant, mask;
8541                       int unsignedp, bits;
8542
8543                       if (host_integerp (primop0, 0))
8544                         {
8545                           primop = primop1;
8546                           unsignedp = unsignedp1;
8547                           constant = tree_low_cst (primop0, 0);
8548                         }
8549                       else
8550                         {
8551                           primop = primop0;
8552                           unsignedp = unsignedp0;
8553                           constant = tree_low_cst (primop1, 0);
8554                         }
8555
8556                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8557                       if (bits < TYPE_PRECISION (result_type)
8558                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8559                         {
8560                           mask = (~(HOST_WIDE_INT) 0) << bits;
8561                           if ((mask & constant) != mask)
8562                             warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with constant");
8563                         }
8564                     }
8565                   else if (unsignedp0 && unsignedp1
8566                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8567                                < TYPE_PRECISION (result_type))
8568                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8569                                < TYPE_PRECISION (result_type)))
8570                     warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with unsigned");
8571                 }
8572             }
8573         }
8574     }
8575
8576   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8577      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8578      Then the expression will be built.
8579      It will be given type FINAL_TYPE if that is nonzero;
8580      otherwise, it will be given type RESULT_TYPE.  */
8581
8582   if (!result_type)
8583     {
8584       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8585       return error_mark_node;
8586     }
8587
8588   if (!converted)
8589     {
8590       if (TREE_TYPE (op0) != result_type)
8591         op0 = convert_and_check (result_type, op0);
8592       if (TREE_TYPE (op1) != result_type)
8593         op1 = convert_and_check (result_type, op1);
8594
8595       /* This can happen if one operand has a vector type, and the other
8596          has a different type.  */
8597       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8598         return error_mark_node;
8599     }
8600
8601   if (build_type == NULL_TREE)
8602     build_type = result_type;
8603
8604   {
8605     /* Treat expressions in initializers specially as they can't trap.  */
8606     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8607                                                                     build_type,
8608                                                                     op0, op1)
8609                                          : fold_build2 (resultcode, build_type,
8610                                                         op0, op1);
8611
8612     if (final_type != 0)
8613       result = convert (final_type, result);
8614     return result;
8615   }
8616 }
8617
8618
8619 /* Convert EXPR to be a truth-value, validating its type for this
8620    purpose.  */
8621
8622 tree
8623 c_objc_common_truthvalue_conversion (tree expr)
8624 {
8625   switch (TREE_CODE (TREE_TYPE (expr)))
8626     {
8627     case ARRAY_TYPE:
8628       error ("used array that cannot be converted to pointer where scalar is required");
8629       return error_mark_node;
8630
8631     case RECORD_TYPE:
8632       error ("used struct type value where scalar is required");
8633       return error_mark_node;
8634
8635     case UNION_TYPE:
8636       error ("used union type value where scalar is required");
8637       return error_mark_node;
8638
8639     case FUNCTION_TYPE:
8640       gcc_unreachable ();
8641
8642     default:
8643       break;
8644     }
8645
8646   /* ??? Should we also give an error for void and vectors rather than
8647      leaving those to give errors later?  */
8648   return c_common_truthvalue_conversion (expr);
8649 }
8650 \f
8651
8652 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8653    required.  */
8654
8655 tree
8656 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8657 {
8658   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8659     {
8660       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8661       /* Executing a compound literal inside a function reinitializes
8662          it.  */
8663       if (!TREE_STATIC (decl))
8664         *se = true;
8665       return decl;
8666     }
8667   else
8668     return expr;
8669 }
8670 \f
8671 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8672
8673 tree
8674 c_begin_omp_parallel (void)
8675 {
8676   tree block;
8677
8678   keep_next_level ();
8679   block = c_begin_compound_stmt (true);
8680
8681   return block;
8682 }
8683
8684 tree
8685 c_finish_omp_parallel (tree clauses, tree block)
8686 {
8687   tree stmt;
8688
8689   block = c_end_compound_stmt (block, true);
8690
8691   stmt = make_node (OMP_PARALLEL);
8692   TREE_TYPE (stmt) = void_type_node;
8693   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8694   OMP_PARALLEL_BODY (stmt) = block;
8695
8696   return add_stmt (stmt);
8697 }
8698
8699 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8700    Remove any elements from the list that are invalid.  */
8701
8702 tree
8703 c_finish_omp_clauses (tree clauses)
8704 {
8705   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8706   tree c, t, *pc = &clauses;
8707   const char *name;
8708
8709   bitmap_obstack_initialize (NULL);
8710   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8711   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8712   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8713
8714   for (pc = &clauses, c = clauses; c ; c = *pc)
8715     {
8716       bool remove = false;
8717       bool need_complete = false;
8718       bool need_implicitly_determined = false;
8719
8720       switch (OMP_CLAUSE_CODE (c))
8721         {
8722         case OMP_CLAUSE_SHARED:
8723           name = "shared";
8724           need_implicitly_determined = true;
8725           goto check_dup_generic;
8726
8727         case OMP_CLAUSE_PRIVATE:
8728           name = "private";
8729           need_complete = true;
8730           need_implicitly_determined = true;
8731           goto check_dup_generic;
8732
8733         case OMP_CLAUSE_REDUCTION:
8734           name = "reduction";
8735           need_implicitly_determined = true;
8736           t = OMP_CLAUSE_DECL (c);
8737           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8738               || POINTER_TYPE_P (TREE_TYPE (t)))
8739             {
8740               error ("%qE has invalid type for %<reduction%>", t);
8741               remove = true;
8742             }
8743           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8744             {
8745               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8746               const char *r_name = NULL;
8747
8748               switch (r_code)
8749                 {
8750                 case PLUS_EXPR:
8751                 case MULT_EXPR:
8752                 case MINUS_EXPR:
8753                   break;
8754                 case BIT_AND_EXPR:
8755                   r_name = "&";
8756                   break;
8757                 case BIT_XOR_EXPR:
8758                   r_name = "^";
8759                   break;
8760                 case BIT_IOR_EXPR:
8761                   r_name = "|";
8762                   break;
8763                 case TRUTH_ANDIF_EXPR:
8764                   r_name = "&&";
8765                   break;
8766                 case TRUTH_ORIF_EXPR:
8767                   r_name = "||";
8768                   break;
8769                 default:
8770                   gcc_unreachable ();
8771                 }
8772               if (r_name)
8773                 {
8774                   error ("%qE has invalid type for %<reduction(%s)%>",
8775                          t, r_name);
8776                   remove = true;
8777                 }
8778             }
8779           goto check_dup_generic;
8780
8781         case OMP_CLAUSE_COPYPRIVATE:
8782           name = "copyprivate";
8783           goto check_dup_generic;
8784
8785         case OMP_CLAUSE_COPYIN:
8786           name = "copyin";
8787           t = OMP_CLAUSE_DECL (c);
8788           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8789             {
8790               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8791               remove = true;
8792             }
8793           goto check_dup_generic;
8794
8795         check_dup_generic:
8796           t = OMP_CLAUSE_DECL (c);
8797           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8798             {
8799               error ("%qE is not a variable in clause %qs", t, name);
8800               remove = true;
8801             }
8802           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8803                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8804                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8805             {
8806               error ("%qE appears more than once in data clauses", t);
8807               remove = true;
8808             }
8809           else
8810             bitmap_set_bit (&generic_head, DECL_UID (t));
8811           break;
8812
8813         case OMP_CLAUSE_FIRSTPRIVATE:
8814           name = "firstprivate";
8815           t = OMP_CLAUSE_DECL (c);
8816           need_complete = true;
8817           need_implicitly_determined = true;
8818           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8819             {
8820               error ("%qE is not a variable in clause %<firstprivate%>", t);
8821               remove = true;
8822             }
8823           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8824                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8825             {
8826               error ("%qE appears more than once in data clauses", t);
8827               remove = true;
8828             }
8829           else
8830             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8831           break;
8832
8833         case OMP_CLAUSE_LASTPRIVATE:
8834           name = "lastprivate";
8835           t = OMP_CLAUSE_DECL (c);
8836           need_complete = true;
8837           need_implicitly_determined = true;
8838           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8839             {
8840               error ("%qE is not a variable in clause %<lastprivate%>", t);
8841               remove = true;
8842             }
8843           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8844                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8845             {
8846               error ("%qE appears more than once in data clauses", t);
8847               remove = true;
8848             }
8849           else
8850             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8851           break;
8852
8853         case OMP_CLAUSE_IF:
8854         case OMP_CLAUSE_NUM_THREADS:
8855         case OMP_CLAUSE_SCHEDULE:
8856         case OMP_CLAUSE_NOWAIT:
8857         case OMP_CLAUSE_ORDERED:
8858         case OMP_CLAUSE_DEFAULT:
8859           pc = &OMP_CLAUSE_CHAIN (c);
8860           continue;
8861
8862         default:
8863           gcc_unreachable ();
8864         }
8865
8866       if (!remove)
8867         {
8868           t = OMP_CLAUSE_DECL (c);
8869
8870           if (need_complete)
8871             {
8872               t = require_complete_type (t);
8873               if (t == error_mark_node)
8874                 remove = true;
8875             }
8876
8877           if (need_implicitly_determined)
8878             {
8879               const char *share_name = NULL;
8880
8881               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8882                 share_name = "threadprivate";
8883               else switch (c_omp_predetermined_sharing (t))
8884                 {
8885                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8886                   break;
8887                 case OMP_CLAUSE_DEFAULT_SHARED:
8888                   share_name = "shared";
8889                   break;
8890                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8891                   share_name = "private";
8892                   break;
8893                 default:
8894                   gcc_unreachable ();
8895                 }
8896               if (share_name)
8897                 {
8898                   error ("%qE is predetermined %qs for %qs",
8899                          t, share_name, name);
8900                   remove = true;
8901                 }
8902             }
8903         }
8904
8905       if (remove)
8906         *pc = OMP_CLAUSE_CHAIN (c);
8907       else
8908         pc = &OMP_CLAUSE_CHAIN (c);
8909     }
8910
8911   bitmap_obstack_release (NULL);
8912   return clauses;
8913 }
8914
8915 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8916    down to the element type of an array.  */
8917
8918 tree
8919 c_build_qualified_type (tree type, int type_quals)
8920 {
8921   if (type == error_mark_node)
8922     return type;
8923
8924   if (TREE_CODE (type) == ARRAY_TYPE)
8925     {
8926       tree t;
8927       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8928                                                   type_quals);
8929
8930       /* See if we already have an identically qualified type.  */
8931       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8932         {
8933           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8934               && TYPE_NAME (t) == TYPE_NAME (type)
8935               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8936               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8937                                        TYPE_ATTRIBUTES (type)))
8938             break;
8939         }
8940       if (!t)
8941         {
8942           tree domain = TYPE_DOMAIN (type);
8943
8944           t = build_variant_type_copy (type);
8945           TREE_TYPE (t) = element_type;
8946
8947           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8948               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8949             SET_TYPE_STRUCTURAL_EQUALITY (t);
8950           else if (TYPE_CANONICAL (element_type) != element_type
8951                    || (domain && TYPE_CANONICAL (domain) != domain))
8952             {
8953               tree unqualified_canon
8954                 = build_array_type (TYPE_CANONICAL (element_type),
8955                                     domain? TYPE_CANONICAL (domain)
8956                                           : NULL_TREE);
8957               TYPE_CANONICAL (t)
8958                 = c_build_qualified_type (unqualified_canon, type_quals);
8959             }
8960           else
8961             TYPE_CANONICAL (t) = t;
8962         }
8963       return t;
8964     }
8965
8966   /* A restrict-qualified pointer type must be a pointer to object or
8967      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8968      REFERENCE_TYPEs, which is appropriate for C++.  */
8969   if ((type_quals & TYPE_QUAL_RESTRICT)
8970       && (!POINTER_TYPE_P (type)
8971           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8972     {
8973       error ("invalid use of %<restrict%>");
8974       type_quals &= ~TYPE_QUAL_RESTRICT;
8975     }
8976
8977   return build_qualified_type (type, type_quals);
8978 }