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               enum mode_class mclass = (enum mode_class) 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               enum mode_class mclass = (enum mode_class) 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 (TREE_CODE_CLASS (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 = vector_targets_convertible_p (ttl, ttr);
4200
4201       /* C++ does not allow the implicit conversion void* -> T*.  However,
4202          for the purpose of reducing the number of false positives, we
4203          tolerate the special case of
4204
4205                 int *p = NULL;
4206
4207          where NULL is typically defined in C to be '(void *) 0'.  */
4208       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4209         warning (OPT_Wc___compat, "request for implicit conversion from "
4210                  "%qT to %qT not permitted in C++", rhstype, type);
4211
4212       /* Check if the right-hand side has a format attribute but the
4213          left-hand side doesn't.  */
4214       if (warn_missing_format_attribute
4215           && check_missing_format_attribute (type, rhstype))
4216         {
4217           switch (errtype)
4218           {
4219           case ic_argpass:
4220           case ic_argpass_nonproto:
4221             warning (OPT_Wmissing_format_attribute,
4222                      "argument %d of %qE might be "
4223                      "a candidate for a format attribute",
4224                      parmnum, rname);
4225             break;
4226           case ic_assign:
4227             warning (OPT_Wmissing_format_attribute,
4228                      "assignment left-hand side might be "
4229                      "a candidate for a format attribute");
4230             break;
4231           case ic_init:
4232             warning (OPT_Wmissing_format_attribute,
4233                      "initialization left-hand side might be "
4234                      "a candidate for a format attribute");
4235             break;
4236           case ic_return:
4237             warning (OPT_Wmissing_format_attribute,
4238                      "return type might be "
4239                      "a candidate for a format attribute");
4240             break;
4241           default:
4242             gcc_unreachable ();
4243           }
4244         }
4245
4246       /* Any non-function converts to a [const][volatile] void *
4247          and vice versa; otherwise, targets must be the same.
4248          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4249       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4250           || (target_cmp = comp_target_types (type, rhstype))
4251           || is_opaque_pointer
4252           || (c_common_unsigned_type (mvl)
4253               == c_common_unsigned_type (mvr)))
4254         {
4255           if (pedantic
4256               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4257                   ||
4258                   (VOID_TYPE_P (ttr)
4259                    && !null_pointer_constant_p (rhs)
4260                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4261             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4262                                     "%qE between function pointer "
4263                                     "and %<void *%>"),
4264                                  G_("ISO C forbids assignment between "
4265                                     "function pointer and %<void *%>"),
4266                                  G_("ISO C forbids initialization between "
4267                                     "function pointer and %<void *%>"),
4268                                  G_("ISO C forbids return between function "
4269                                     "pointer and %<void *%>"));
4270           /* Const and volatile mean something different for function types,
4271              so the usual warnings are not appropriate.  */
4272           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4273                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4274             {
4275               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4276                 {
4277                   /* Types differing only by the presence of the 'volatile'
4278                      qualifier are acceptable if the 'volatile' has been added
4279                      in by the Objective-C EH machinery.  */
4280                   if (!objc_type_quals_match (ttl, ttr))
4281                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4282                                             "qualifiers from pointer target type"),
4283                                          G_("assignment discards qualifiers "
4284                                             "from pointer target type"),
4285                                          G_("initialization discards qualifiers "
4286                                             "from pointer target type"),
4287                                          G_("return discards qualifiers from "
4288                                             "pointer target type"));
4289                 }
4290               /* If this is not a case of ignoring a mismatch in signedness,
4291                  no warning.  */
4292               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4293                        || target_cmp)
4294                 ;
4295               /* If there is a mismatch, do warn.  */
4296               else if (warn_pointer_sign)
4297                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4298                                         "%d of %qE differ in signedness"),
4299                                      G_("pointer targets in assignment "
4300                                         "differ in signedness"),
4301                                      G_("pointer targets in initialization "
4302                                         "differ in signedness"),
4303                                      G_("pointer targets in return differ "
4304                                         "in signedness"));
4305             }
4306           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4307                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4308             {
4309               /* Because const and volatile on functions are restrictions
4310                  that say the function will not do certain things,
4311                  it is okay to use a const or volatile function
4312                  where an ordinary one is wanted, but not vice-versa.  */
4313               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4314                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4315                                         "qualified function pointer "
4316                                         "from unqualified"),
4317                                      G_("assignment makes qualified function "
4318                                         "pointer from unqualified"),
4319                                      G_("initialization makes qualified "
4320                                         "function pointer from unqualified"),
4321                                      G_("return makes qualified function "
4322                                         "pointer from unqualified"));
4323             }
4324         }
4325       else
4326         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4327         if (!objc_ok)
4328           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4329                                   "incompatible pointer type"),
4330                                G_("assignment from incompatible pointer type"),
4331                                G_("initialization from incompatible "
4332                                   "pointer type"),
4333                                G_("return from incompatible pointer type"));
4334
4335       return convert (type, rhs);
4336     }
4337   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4338     {
4339       /* ??? This should not be an error when inlining calls to
4340          unprototyped functions.  */
4341       error ("invalid use of non-lvalue array");
4342       return error_mark_node;
4343     }
4344   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4345     {
4346       /* An explicit constant 0 can convert to a pointer,
4347          or one that results from arithmetic, even including
4348          a cast to integer type.  */
4349       if (!null_pointer_constant_p (rhs))
4350         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4351                                 "pointer from integer without a cast"),
4352                              G_("assignment makes pointer from integer "
4353                                 "without a cast"),
4354                              G_("initialization makes pointer from "
4355                                 "integer without a cast"),
4356                              G_("return makes pointer from integer "
4357                                 "without a cast"));
4358
4359       return convert (type, rhs);
4360     }
4361   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4362     {
4363       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4364                               "from pointer without a cast"),
4365                            G_("assignment makes integer from pointer "
4366                               "without a cast"),
4367                            G_("initialization makes integer from pointer "
4368                               "without a cast"),
4369                            G_("return makes integer from pointer "
4370                               "without a cast"));
4371       return convert (type, rhs);
4372     }
4373   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4374     return convert (type, rhs);
4375
4376   switch (errtype)
4377     {
4378     case ic_argpass:
4379     case ic_argpass_nonproto:
4380       /* ??? This should not be an error when inlining calls to
4381          unprototyped functions.  */
4382       error ("incompatible type for argument %d of %qE", parmnum, rname);
4383       break;
4384     case ic_assign:
4385       error ("incompatible types in assignment");
4386       break;
4387     case ic_init:
4388       error ("incompatible types in initialization");
4389       break;
4390     case ic_return:
4391       error ("incompatible types in return");
4392       break;
4393     default:
4394       gcc_unreachable ();
4395     }
4396
4397   return error_mark_node;
4398 }
4399 \f
4400 /* If VALUE is a compound expr all of whose expressions are constant, then
4401    return its value.  Otherwise, return error_mark_node.
4402
4403    This is for handling COMPOUND_EXPRs as initializer elements
4404    which is allowed with a warning when -pedantic is specified.  */
4405
4406 static tree
4407 valid_compound_expr_initializer (tree value, tree endtype)
4408 {
4409   if (TREE_CODE (value) == COMPOUND_EXPR)
4410     {
4411       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4412           == error_mark_node)
4413         return error_mark_node;
4414       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4415                                               endtype);
4416     }
4417   else if (!initializer_constant_valid_p (value, endtype))
4418     return error_mark_node;
4419   else
4420     return value;
4421 }
4422 \f
4423 /* Perform appropriate conversions on the initial value of a variable,
4424    store it in the declaration DECL,
4425    and print any error messages that are appropriate.
4426    If the init is invalid, store an ERROR_MARK.  */
4427
4428 void
4429 store_init_value (tree decl, tree init)
4430 {
4431   tree value, type;
4432
4433   /* If variable's type was invalidly declared, just ignore it.  */
4434
4435   type = TREE_TYPE (decl);
4436   if (TREE_CODE (type) == ERROR_MARK)
4437     return;
4438
4439   /* Digest the specified initializer into an expression.  */
4440
4441   value = digest_init (type, init, true, TREE_STATIC (decl));
4442
4443   /* Store the expression if valid; else report error.  */
4444
4445   if (!in_system_header
4446       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4447     warning (OPT_Wtraditional, "traditional C rejects automatic "
4448              "aggregate initialization");
4449
4450   DECL_INITIAL (decl) = value;
4451
4452   /* ANSI wants warnings about out-of-range constant initializers.  */
4453   STRIP_TYPE_NOPS (value);
4454   if (TREE_STATIC (decl))
4455     constant_expression_warning (value);
4456
4457   /* Check if we need to set array size from compound literal size.  */
4458   if (TREE_CODE (type) == ARRAY_TYPE
4459       && TYPE_DOMAIN (type) == 0
4460       && value != error_mark_node)
4461     {
4462       tree inside_init = init;
4463
4464       STRIP_TYPE_NOPS (inside_init);
4465       inside_init = fold (inside_init);
4466
4467       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4468         {
4469           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4470
4471           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4472             {
4473               /* For int foo[] = (int [3]){1}; we need to set array size
4474                  now since later on array initializer will be just the
4475                  brace enclosed list of the compound literal.  */
4476               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4477               TREE_TYPE (decl) = type;
4478               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4479               layout_type (type);
4480               layout_decl (cldecl, 0);
4481             }
4482         }
4483     }
4484 }
4485 \f
4486 /* Methods for storing and printing names for error messages.  */
4487
4488 /* Implement a spelling stack that allows components of a name to be pushed
4489    and popped.  Each element on the stack is this structure.  */
4490
4491 struct spelling
4492 {
4493   int kind;
4494   union
4495     {
4496       unsigned HOST_WIDE_INT i;
4497       const char *s;
4498     } u;
4499 };
4500
4501 #define SPELLING_STRING 1
4502 #define SPELLING_MEMBER 2
4503 #define SPELLING_BOUNDS 3
4504
4505 static struct spelling *spelling;       /* Next stack element (unused).  */
4506 static struct spelling *spelling_base;  /* Spelling stack base.  */
4507 static int spelling_size;               /* Size of the spelling stack.  */
4508
4509 /* Macros to save and restore the spelling stack around push_... functions.
4510    Alternative to SAVE_SPELLING_STACK.  */
4511
4512 #define SPELLING_DEPTH() (spelling - spelling_base)
4513 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4514
4515 /* Push an element on the spelling stack with type KIND and assign VALUE
4516    to MEMBER.  */
4517
4518 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4519 {                                                                       \
4520   int depth = SPELLING_DEPTH ();                                        \
4521                                                                         \
4522   if (depth >= spelling_size)                                           \
4523     {                                                                   \
4524       spelling_size += 10;                                              \
4525       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4526                                   spelling_size);                       \
4527       RESTORE_SPELLING_DEPTH (depth);                                   \
4528     }                                                                   \
4529                                                                         \
4530   spelling->kind = (KIND);                                              \
4531   spelling->MEMBER = (VALUE);                                           \
4532   spelling++;                                                           \
4533 }
4534
4535 /* Push STRING on the stack.  Printed literally.  */
4536
4537 static void
4538 push_string (const char *string)
4539 {
4540   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4541 }
4542
4543 /* Push a member name on the stack.  Printed as '.' STRING.  */
4544
4545 static void
4546 push_member_name (tree decl)
4547 {
4548   const char *const string
4549     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4550   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4551 }
4552
4553 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4554
4555 static void
4556 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4557 {
4558   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4559 }
4560
4561 /* Compute the maximum size in bytes of the printed spelling.  */
4562
4563 static int
4564 spelling_length (void)
4565 {
4566   int size = 0;
4567   struct spelling *p;
4568
4569   for (p = spelling_base; p < spelling; p++)
4570     {
4571       if (p->kind == SPELLING_BOUNDS)
4572         size += 25;
4573       else
4574         size += strlen (p->u.s) + 1;
4575     }
4576
4577   return size;
4578 }
4579
4580 /* Print the spelling to BUFFER and return it.  */
4581
4582 static char *
4583 print_spelling (char *buffer)
4584 {
4585   char *d = buffer;
4586   struct spelling *p;
4587
4588   for (p = spelling_base; p < spelling; p++)
4589     if (p->kind == SPELLING_BOUNDS)
4590       {
4591         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4592         d += strlen (d);
4593       }
4594     else
4595       {
4596         const char *s;
4597         if (p->kind == SPELLING_MEMBER)
4598           *d++ = '.';
4599         for (s = p->u.s; (*d = *s++); d++)
4600           ;
4601       }
4602   *d++ = '\0';
4603   return buffer;
4604 }
4605
4606 /* Issue an error message for a bad initializer component.
4607    MSGID identifies the message.
4608    The component name is taken from the spelling stack.  */
4609
4610 void
4611 error_init (const char *msgid)
4612 {
4613   char *ofwhat;
4614
4615   error ("%s", _(msgid));
4616   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4617   if (*ofwhat)
4618     error ("(near initialization for %qs)", ofwhat);
4619 }
4620
4621 /* Issue a pedantic warning for a bad initializer component.
4622    MSGID identifies the message.
4623    The component name is taken from the spelling stack.  */
4624
4625 void
4626 pedwarn_init (const char *msgid)
4627 {
4628   char *ofwhat;
4629
4630   pedwarn ("%s", _(msgid));
4631   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4632   if (*ofwhat)
4633     pedwarn ("(near initialization for %qs)", ofwhat);
4634 }
4635
4636 /* Issue a warning for a bad initializer component.
4637
4638    OPT is the OPT_W* value corresponding to the warning option that
4639    controls this warning.  MSGID identifies the message.  The
4640    component name is taken from the spelling stack.  */
4641
4642 static void
4643 warning_init (int opt, const char *msgid)
4644 {
4645   char *ofwhat;
4646
4647   warning (opt, "%s", _(msgid));
4648   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4649   if (*ofwhat)
4650     warning (opt, "(near initialization for %qs)", ofwhat);
4651 }
4652 \f
4653 /* If TYPE is an array type and EXPR is a parenthesized string
4654    constant, warn if pedantic that EXPR is being used to initialize an
4655    object of type TYPE.  */
4656
4657 void
4658 maybe_warn_string_init (tree type, struct c_expr expr)
4659 {
4660   if (pedantic
4661       && TREE_CODE (type) == ARRAY_TYPE
4662       && TREE_CODE (expr.value) == STRING_CST
4663       && expr.original_code != STRING_CST)
4664     pedwarn_init ("array initialized from parenthesized string constant");
4665 }
4666
4667 /* Digest the parser output INIT as an initializer for type TYPE.
4668    Return a C expression of type TYPE to represent the initial value.
4669
4670    If INIT is a string constant, STRICT_STRING is true if it is
4671    unparenthesized or we should not warn here for it being parenthesized.
4672    For other types of INIT, STRICT_STRING is not used.
4673
4674    REQUIRE_CONSTANT requests an error if non-constant initializers or
4675    elements are seen.  */
4676
4677 static tree
4678 digest_init (tree type, tree init, bool strict_string, int require_constant)
4679 {
4680   enum tree_code code = TREE_CODE (type);
4681   tree inside_init = init;
4682
4683   if (type == error_mark_node
4684       || !init
4685       || init == error_mark_node
4686       || TREE_TYPE (init) == error_mark_node)
4687     return error_mark_node;
4688
4689   STRIP_TYPE_NOPS (inside_init);
4690
4691   inside_init = fold (inside_init);
4692
4693   /* Initialization of an array of chars from a string constant
4694      optionally enclosed in braces.  */
4695
4696   if (code == ARRAY_TYPE && inside_init
4697       && TREE_CODE (inside_init) == STRING_CST)
4698     {
4699       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4700       /* Note that an array could be both an array of character type
4701          and an array of wchar_t if wchar_t is signed char or unsigned
4702          char.  */
4703       bool char_array = (typ1 == char_type_node
4704                          || typ1 == signed_char_type_node
4705                          || typ1 == unsigned_char_type_node);
4706       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4707       if (char_array || wchar_array)
4708         {
4709           struct c_expr expr;
4710           bool char_string;
4711           expr.value = inside_init;
4712           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4713           maybe_warn_string_init (type, expr);
4714
4715           char_string
4716             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4717                == char_type_node);
4718
4719           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4720                          TYPE_MAIN_VARIANT (type)))
4721             return inside_init;
4722
4723           if (!wchar_array && !char_string)
4724             {
4725               error_init ("char-array initialized from wide string");
4726               return error_mark_node;
4727             }
4728           if (char_string && !char_array)
4729             {
4730               error_init ("wchar_t-array initialized from non-wide string");
4731               return error_mark_node;
4732             }
4733
4734           TREE_TYPE (inside_init) = type;
4735           if (TYPE_DOMAIN (type) != 0
4736               && TYPE_SIZE (type) != 0
4737               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4738               /* Subtract 1 (or sizeof (wchar_t))
4739                  because it's ok to ignore the terminating null char
4740                  that is counted in the length of the constant.  */
4741               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4742                                        TREE_STRING_LENGTH (inside_init)
4743                                        - ((TYPE_PRECISION (typ1)
4744                                            != TYPE_PRECISION (char_type_node))
4745                                           ? (TYPE_PRECISION (wchar_type_node)
4746                                              / BITS_PER_UNIT)
4747                                           : 1)))
4748             pedwarn_init ("initializer-string for array of chars is too long");
4749
4750           return inside_init;
4751         }
4752       else if (INTEGRAL_TYPE_P (typ1))
4753         {
4754           error_init ("array of inappropriate type initialized "
4755                       "from string constant");
4756           return error_mark_node;
4757         }
4758     }
4759
4760   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4761      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4762      below and handle as a constructor.  */
4763   if (code == VECTOR_TYPE
4764       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4765       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4766       && TREE_CONSTANT (inside_init))
4767     {
4768       if (TREE_CODE (inside_init) == VECTOR_CST
4769           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4770                         TYPE_MAIN_VARIANT (type)))
4771         return inside_init;
4772
4773       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4774         {
4775           unsigned HOST_WIDE_INT ix;
4776           tree value;
4777           bool constant_p = true;
4778
4779           /* Iterate through elements and check if all constructor
4780              elements are *_CSTs.  */
4781           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4782             if (!CONSTANT_CLASS_P (value))
4783               {
4784                 constant_p = false;
4785                 break;
4786               }
4787
4788           if (constant_p)
4789             return build_vector_from_ctor (type,
4790                                            CONSTRUCTOR_ELTS (inside_init));
4791         }
4792     }
4793
4794   /* Any type can be initialized
4795      from an expression of the same type, optionally with braces.  */
4796
4797   if (inside_init && TREE_TYPE (inside_init) != 0
4798       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4799                      TYPE_MAIN_VARIANT (type))
4800           || (code == ARRAY_TYPE
4801               && comptypes (TREE_TYPE (inside_init), type))
4802           || (code == VECTOR_TYPE
4803               && comptypes (TREE_TYPE (inside_init), type))
4804           || (code == POINTER_TYPE
4805               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4806               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4807                             TREE_TYPE (type)))))
4808     {
4809       if (code == POINTER_TYPE)
4810         {
4811           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4812             {
4813               if (TREE_CODE (inside_init) == STRING_CST
4814                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4815                 inside_init = array_to_pointer_conversion (inside_init);
4816               else
4817                 {
4818                   error_init ("invalid use of non-lvalue array");
4819                   return error_mark_node;
4820                 }
4821             }
4822         }
4823
4824       if (code == VECTOR_TYPE)
4825         /* Although the types are compatible, we may require a
4826            conversion.  */
4827         inside_init = convert (type, inside_init);
4828
4829       if (require_constant
4830           && (code == VECTOR_TYPE || !flag_isoc99)
4831           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4832         {
4833           /* As an extension, allow initializing objects with static storage
4834              duration with compound literals (which are then treated just as
4835              the brace enclosed list they contain).  Also allow this for
4836              vectors, as we can only assign them with compound literals.  */
4837           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4838           inside_init = DECL_INITIAL (decl);
4839         }
4840
4841       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4842           && TREE_CODE (inside_init) != CONSTRUCTOR)
4843         {
4844           error_init ("array initialized from non-constant array expression");
4845           return error_mark_node;
4846         }
4847
4848       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4849         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4850
4851       /* Compound expressions can only occur here if -pedantic or
4852          -pedantic-errors is specified.  In the later case, we always want
4853          an error.  In the former case, we simply want a warning.  */
4854       if (require_constant && pedantic
4855           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4856         {
4857           inside_init
4858             = valid_compound_expr_initializer (inside_init,
4859                                                TREE_TYPE (inside_init));
4860           if (inside_init == error_mark_node)
4861             error_init ("initializer element is not constant");
4862           else
4863             pedwarn_init ("initializer element is not constant");
4864           if (flag_pedantic_errors)
4865             inside_init = error_mark_node;
4866         }
4867       else if (require_constant
4868                && !initializer_constant_valid_p (inside_init,
4869                                                  TREE_TYPE (inside_init)))
4870         {
4871           error_init ("initializer element is not constant");
4872           inside_init = error_mark_node;
4873         }
4874
4875       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4876       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4877         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4878                                               NULL_TREE, 0);
4879       return inside_init;
4880     }
4881
4882   /* Handle scalar types, including conversions.  */
4883
4884   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4885       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4886       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4887     {
4888       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4889           && (TREE_CODE (init) == STRING_CST
4890               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4891         init = array_to_pointer_conversion (init);
4892       inside_init
4893         = convert_for_assignment (type, init, ic_init,
4894                                   NULL_TREE, NULL_TREE, 0);
4895
4896       /* Check to see if we have already given an error message.  */
4897       if (inside_init == error_mark_node)
4898         ;
4899       else if (require_constant && !TREE_CONSTANT (inside_init))
4900         {
4901           error_init ("initializer element is not constant");
4902           inside_init = error_mark_node;
4903         }
4904       else if (require_constant
4905                && !initializer_constant_valid_p (inside_init,
4906                                                  TREE_TYPE (inside_init)))
4907         {
4908           error_init ("initializer element is not computable at load time");
4909           inside_init = error_mark_node;
4910         }
4911
4912       return inside_init;
4913     }
4914
4915   /* Come here only for records and arrays.  */
4916
4917   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4918     {
4919       error_init ("variable-sized object may not be initialized");
4920       return error_mark_node;
4921     }
4922
4923   error_init ("invalid initializer");
4924   return error_mark_node;
4925 }
4926 \f
4927 /* Handle initializers that use braces.  */
4928
4929 /* Type of object we are accumulating a constructor for.
4930    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4931 static tree constructor_type;
4932
4933 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4934    left to fill.  */
4935 static tree constructor_fields;
4936
4937 /* For an ARRAY_TYPE, this is the specified index
4938    at which to store the next element we get.  */
4939 static tree constructor_index;
4940
4941 /* For an ARRAY_TYPE, this is the maximum index.  */
4942 static tree constructor_max_index;
4943
4944 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4945 static tree constructor_unfilled_fields;
4946
4947 /* For an ARRAY_TYPE, this is the index of the first element
4948    not yet written out.  */
4949 static tree constructor_unfilled_index;
4950
4951 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4952    This is so we can generate gaps between fields, when appropriate.  */
4953 static tree constructor_bit_index;
4954
4955 /* If we are saving up the elements rather than allocating them,
4956    this is the list of elements so far (in reverse order,
4957    most recent first).  */
4958 static VEC(constructor_elt,gc) *constructor_elements;
4959
4960 /* 1 if constructor should be incrementally stored into a constructor chain,
4961    0 if all the elements should be kept in AVL tree.  */
4962 static int constructor_incremental;
4963
4964 /* 1 if so far this constructor's elements are all compile-time constants.  */
4965 static int constructor_constant;
4966
4967 /* 1 if so far this constructor's elements are all valid address constants.  */
4968 static int constructor_simple;
4969
4970 /* 1 if this constructor is erroneous so far.  */
4971 static int constructor_erroneous;
4972
4973 /* Structure for managing pending initializer elements, organized as an
4974    AVL tree.  */
4975
4976 struct init_node
4977 {
4978   struct init_node *left, *right;
4979   struct init_node *parent;
4980   int balance;
4981   tree purpose;
4982   tree value;
4983 };
4984
4985 /* Tree of pending elements at this constructor level.
4986    These are elements encountered out of order
4987    which belong at places we haven't reached yet in actually
4988    writing the output.
4989    Will never hold tree nodes across GC runs.  */
4990 static struct init_node *constructor_pending_elts;
4991
4992 /* The SPELLING_DEPTH of this constructor.  */
4993 static int constructor_depth;
4994
4995 /* DECL node for which an initializer is being read.
4996    0 means we are reading a constructor expression
4997    such as (struct foo) {...}.  */
4998 static tree constructor_decl;
4999
5000 /* Nonzero if this is an initializer for a top-level decl.  */
5001 static int constructor_top_level;
5002
5003 /* Nonzero if there were any member designators in this initializer.  */
5004 static int constructor_designated;
5005
5006 /* Nesting depth of designator list.  */
5007 static int designator_depth;
5008
5009 /* Nonzero if there were diagnosed errors in this designator list.  */
5010 static int designator_erroneous;
5011
5012 \f
5013 /* This stack has a level for each implicit or explicit level of
5014    structuring in the initializer, including the outermost one.  It
5015    saves the values of most of the variables above.  */
5016
5017 struct constructor_range_stack;
5018
5019 struct constructor_stack
5020 {
5021   struct constructor_stack *next;
5022   tree type;
5023   tree fields;
5024   tree index;
5025   tree max_index;
5026   tree unfilled_index;
5027   tree unfilled_fields;
5028   tree bit_index;
5029   VEC(constructor_elt,gc) *elements;
5030   struct init_node *pending_elts;
5031   int offset;
5032   int depth;
5033   /* If value nonzero, this value should replace the entire
5034      constructor at this level.  */
5035   struct c_expr replacement_value;
5036   struct constructor_range_stack *range_stack;
5037   char constant;
5038   char simple;
5039   char implicit;
5040   char erroneous;
5041   char outer;
5042   char incremental;
5043   char designated;
5044 };
5045
5046 static struct constructor_stack *constructor_stack;
5047
5048 /* This stack represents designators from some range designator up to
5049    the last designator in the list.  */
5050
5051 struct constructor_range_stack
5052 {
5053   struct constructor_range_stack *next, *prev;
5054   struct constructor_stack *stack;
5055   tree range_start;
5056   tree index;
5057   tree range_end;
5058   tree fields;
5059 };
5060
5061 static struct constructor_range_stack *constructor_range_stack;
5062
5063 /* This stack records separate initializers that are nested.
5064    Nested initializers can't happen in ANSI C, but GNU C allows them
5065    in cases like { ... (struct foo) { ... } ... }.  */
5066
5067 struct initializer_stack
5068 {
5069   struct initializer_stack *next;
5070   tree decl;
5071   struct constructor_stack *constructor_stack;
5072   struct constructor_range_stack *constructor_range_stack;
5073   VEC(constructor_elt,gc) *elements;
5074   struct spelling *spelling;
5075   struct spelling *spelling_base;
5076   int spelling_size;
5077   char top_level;
5078   char require_constant_value;
5079   char require_constant_elements;
5080 };
5081
5082 static struct initializer_stack *initializer_stack;
5083 \f
5084 /* Prepare to parse and output the initializer for variable DECL.  */
5085
5086 void
5087 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5088 {
5089   const char *locus;
5090   struct initializer_stack *p = XNEW (struct initializer_stack);
5091
5092   p->decl = constructor_decl;
5093   p->require_constant_value = require_constant_value;
5094   p->require_constant_elements = require_constant_elements;
5095   p->constructor_stack = constructor_stack;
5096   p->constructor_range_stack = constructor_range_stack;
5097   p->elements = constructor_elements;
5098   p->spelling = spelling;
5099   p->spelling_base = spelling_base;
5100   p->spelling_size = spelling_size;
5101   p->top_level = constructor_top_level;
5102   p->next = initializer_stack;
5103   initializer_stack = p;
5104
5105   constructor_decl = decl;
5106   constructor_designated = 0;
5107   constructor_top_level = top_level;
5108
5109   if (decl != 0 && decl != error_mark_node)
5110     {
5111       require_constant_value = TREE_STATIC (decl);
5112       require_constant_elements
5113         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5114            /* For a scalar, you can always use any value to initialize,
5115               even within braces.  */
5116            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5117                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5118                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5119                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5120       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5121     }
5122   else
5123     {
5124       require_constant_value = 0;
5125       require_constant_elements = 0;
5126       locus = "(anonymous)";
5127     }
5128
5129   constructor_stack = 0;
5130   constructor_range_stack = 0;
5131
5132   missing_braces_mentioned = 0;
5133
5134   spelling_base = 0;
5135   spelling_size = 0;
5136   RESTORE_SPELLING_DEPTH (0);
5137
5138   if (locus)
5139     push_string (locus);
5140 }
5141
5142 void
5143 finish_init (void)
5144 {
5145   struct initializer_stack *p = initializer_stack;
5146
5147   /* Free the whole constructor stack of this initializer.  */
5148   while (constructor_stack)
5149     {
5150       struct constructor_stack *q = constructor_stack;
5151       constructor_stack = q->next;
5152       free (q);
5153     }
5154
5155   gcc_assert (!constructor_range_stack);
5156
5157   /* Pop back to the data of the outer initializer (if any).  */
5158   free (spelling_base);
5159
5160   constructor_decl = p->decl;
5161   require_constant_value = p->require_constant_value;
5162   require_constant_elements = p->require_constant_elements;
5163   constructor_stack = p->constructor_stack;
5164   constructor_range_stack = p->constructor_range_stack;
5165   constructor_elements = p->elements;
5166   spelling = p->spelling;
5167   spelling_base = p->spelling_base;
5168   spelling_size = p->spelling_size;
5169   constructor_top_level = p->top_level;
5170   initializer_stack = p->next;
5171   free (p);
5172 }
5173 \f
5174 /* Call here when we see the initializer is surrounded by braces.
5175    This is instead of a call to push_init_level;
5176    it is matched by a call to pop_init_level.
5177
5178    TYPE is the type to initialize, for a constructor expression.
5179    For an initializer for a decl, TYPE is zero.  */
5180
5181 void
5182 really_start_incremental_init (tree type)
5183 {
5184   struct constructor_stack *p = XNEW (struct constructor_stack);
5185
5186   if (type == 0)
5187     type = TREE_TYPE (constructor_decl);
5188
5189   if (targetm.vector_opaque_p (type))
5190     error ("opaque vector types cannot be initialized");
5191
5192   p->type = constructor_type;
5193   p->fields = constructor_fields;
5194   p->index = constructor_index;
5195   p->max_index = constructor_max_index;
5196   p->unfilled_index = constructor_unfilled_index;
5197   p->unfilled_fields = constructor_unfilled_fields;
5198   p->bit_index = constructor_bit_index;
5199   p->elements = constructor_elements;
5200   p->constant = constructor_constant;
5201   p->simple = constructor_simple;
5202   p->erroneous = constructor_erroneous;
5203   p->pending_elts = constructor_pending_elts;
5204   p->depth = constructor_depth;
5205   p->replacement_value.value = 0;
5206   p->replacement_value.original_code = ERROR_MARK;
5207   p->implicit = 0;
5208   p->range_stack = 0;
5209   p->outer = 0;
5210   p->incremental = constructor_incremental;
5211   p->designated = constructor_designated;
5212   p->next = 0;
5213   constructor_stack = p;
5214
5215   constructor_constant = 1;
5216   constructor_simple = 1;
5217   constructor_depth = SPELLING_DEPTH ();
5218   constructor_elements = 0;
5219   constructor_pending_elts = 0;
5220   constructor_type = type;
5221   constructor_incremental = 1;
5222   constructor_designated = 0;
5223   designator_depth = 0;
5224   designator_erroneous = 0;
5225
5226   if (TREE_CODE (constructor_type) == RECORD_TYPE
5227       || TREE_CODE (constructor_type) == UNION_TYPE)
5228     {
5229       constructor_fields = TYPE_FIELDS (constructor_type);
5230       /* Skip any nameless bit fields at the beginning.  */
5231       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5232              && DECL_NAME (constructor_fields) == 0)
5233         constructor_fields = TREE_CHAIN (constructor_fields);
5234
5235       constructor_unfilled_fields = constructor_fields;
5236       constructor_bit_index = bitsize_zero_node;
5237     }
5238   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5239     {
5240       if (TYPE_DOMAIN (constructor_type))
5241         {
5242           constructor_max_index
5243             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5244
5245           /* Detect non-empty initializations of zero-length arrays.  */
5246           if (constructor_max_index == NULL_TREE
5247               && TYPE_SIZE (constructor_type))
5248             constructor_max_index = build_int_cst (NULL_TREE, -1);
5249
5250           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5251              to initialize VLAs will cause a proper error; avoid tree
5252              checking errors as well by setting a safe value.  */
5253           if (constructor_max_index
5254               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5255             constructor_max_index = build_int_cst (NULL_TREE, -1);
5256
5257           constructor_index
5258             = convert (bitsizetype,
5259                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5260         }
5261       else
5262         {
5263           constructor_index = bitsize_zero_node;
5264           constructor_max_index = NULL_TREE;
5265         }
5266
5267       constructor_unfilled_index = constructor_index;
5268     }
5269   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5270     {
5271       /* Vectors are like simple fixed-size arrays.  */
5272       constructor_max_index =
5273         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5274       constructor_index = bitsize_zero_node;
5275       constructor_unfilled_index = constructor_index;
5276     }
5277   else
5278     {
5279       /* Handle the case of int x = {5}; */
5280       constructor_fields = constructor_type;
5281       constructor_unfilled_fields = constructor_type;
5282     }
5283 }
5284 \f
5285 /* Push down into a subobject, for initialization.
5286    If this is for an explicit set of braces, IMPLICIT is 0.
5287    If it is because the next element belongs at a lower level,
5288    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5289
5290 void
5291 push_init_level (int implicit)
5292 {
5293   struct constructor_stack *p;
5294   tree value = NULL_TREE;
5295
5296   /* If we've exhausted any levels that didn't have braces,
5297      pop them now.  If implicit == 1, this will have been done in
5298      process_init_element; do not repeat it here because in the case
5299      of excess initializers for an empty aggregate this leads to an
5300      infinite cycle of popping a level and immediately recreating
5301      it.  */
5302   if (implicit != 1)
5303     {
5304       while (constructor_stack->implicit)
5305         {
5306           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5307                || TREE_CODE (constructor_type) == UNION_TYPE)
5308               && constructor_fields == 0)
5309             process_init_element (pop_init_level (1));
5310           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5311                    && constructor_max_index
5312                    && tree_int_cst_lt (constructor_max_index,
5313                                        constructor_index))
5314             process_init_element (pop_init_level (1));
5315           else
5316             break;
5317         }
5318     }
5319
5320   /* Unless this is an explicit brace, we need to preserve previous
5321      content if any.  */
5322   if (implicit)
5323     {
5324       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5325            || TREE_CODE (constructor_type) == UNION_TYPE)
5326           && constructor_fields)
5327         value = find_init_member (constructor_fields);
5328       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5329         value = find_init_member (constructor_index);
5330     }
5331
5332   p = XNEW (struct constructor_stack);
5333   p->type = constructor_type;
5334   p->fields = constructor_fields;
5335   p->index = constructor_index;
5336   p->max_index = constructor_max_index;
5337   p->unfilled_index = constructor_unfilled_index;
5338   p->unfilled_fields = constructor_unfilled_fields;
5339   p->bit_index = constructor_bit_index;
5340   p->elements = constructor_elements;
5341   p->constant = constructor_constant;
5342   p->simple = constructor_simple;
5343   p->erroneous = constructor_erroneous;
5344   p->pending_elts = constructor_pending_elts;
5345   p->depth = constructor_depth;
5346   p->replacement_value.value = 0;
5347   p->replacement_value.original_code = ERROR_MARK;
5348   p->implicit = implicit;
5349   p->outer = 0;
5350   p->incremental = constructor_incremental;
5351   p->designated = constructor_designated;
5352   p->next = constructor_stack;
5353   p->range_stack = 0;
5354   constructor_stack = p;
5355
5356   constructor_constant = 1;
5357   constructor_simple = 1;
5358   constructor_depth = SPELLING_DEPTH ();
5359   constructor_elements = 0;
5360   constructor_incremental = 1;
5361   constructor_designated = 0;
5362   constructor_pending_elts = 0;
5363   if (!implicit)
5364     {
5365       p->range_stack = constructor_range_stack;
5366       constructor_range_stack = 0;
5367       designator_depth = 0;
5368       designator_erroneous = 0;
5369     }
5370
5371   /* Don't die if an entire brace-pair level is superfluous
5372      in the containing level.  */
5373   if (constructor_type == 0)
5374     ;
5375   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5376            || TREE_CODE (constructor_type) == UNION_TYPE)
5377     {
5378       /* Don't die if there are extra init elts at the end.  */
5379       if (constructor_fields == 0)
5380         constructor_type = 0;
5381       else
5382         {
5383           constructor_type = TREE_TYPE (constructor_fields);
5384           push_member_name (constructor_fields);
5385           constructor_depth++;
5386         }
5387     }
5388   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5389     {
5390       constructor_type = TREE_TYPE (constructor_type);
5391       push_array_bounds (tree_low_cst (constructor_index, 1));
5392       constructor_depth++;
5393     }
5394
5395   if (constructor_type == 0)
5396     {
5397       error_init ("extra brace group at end of initializer");
5398       constructor_fields = 0;
5399       constructor_unfilled_fields = 0;
5400       return;
5401     }
5402
5403   if (value && TREE_CODE (value) == CONSTRUCTOR)
5404     {
5405       constructor_constant = TREE_CONSTANT (value);
5406       constructor_simple = TREE_STATIC (value);
5407       constructor_elements = CONSTRUCTOR_ELTS (value);
5408       if (!VEC_empty (constructor_elt, constructor_elements)
5409           && (TREE_CODE (constructor_type) == RECORD_TYPE
5410               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5411         set_nonincremental_init ();
5412     }
5413
5414   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5415     {
5416       missing_braces_mentioned = 1;
5417       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5418     }
5419
5420   if (TREE_CODE (constructor_type) == RECORD_TYPE
5421            || TREE_CODE (constructor_type) == UNION_TYPE)
5422     {
5423       constructor_fields = TYPE_FIELDS (constructor_type);
5424       /* Skip any nameless bit fields at the beginning.  */
5425       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5426              && DECL_NAME (constructor_fields) == 0)
5427         constructor_fields = TREE_CHAIN (constructor_fields);
5428
5429       constructor_unfilled_fields = constructor_fields;
5430       constructor_bit_index = bitsize_zero_node;
5431     }
5432   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5433     {
5434       /* Vectors are like simple fixed-size arrays.  */
5435       constructor_max_index =
5436         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5437       constructor_index = convert (bitsizetype, integer_zero_node);
5438       constructor_unfilled_index = constructor_index;
5439     }
5440   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5441     {
5442       if (TYPE_DOMAIN (constructor_type))
5443         {
5444           constructor_max_index
5445             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5446
5447           /* Detect non-empty initializations of zero-length arrays.  */
5448           if (constructor_max_index == NULL_TREE
5449               && TYPE_SIZE (constructor_type))
5450             constructor_max_index = build_int_cst (NULL_TREE, -1);
5451
5452           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5453              to initialize VLAs will cause a proper error; avoid tree
5454              checking errors as well by setting a safe value.  */
5455           if (constructor_max_index
5456               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5457             constructor_max_index = build_int_cst (NULL_TREE, -1);
5458
5459           constructor_index
5460             = convert (bitsizetype,
5461                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5462         }
5463       else
5464         constructor_index = bitsize_zero_node;
5465
5466       constructor_unfilled_index = constructor_index;
5467       if (value && TREE_CODE (value) == STRING_CST)
5468         {
5469           /* We need to split the char/wchar array into individual
5470              characters, so that we don't have to special case it
5471              everywhere.  */
5472           set_nonincremental_init_from_string (value);
5473         }
5474     }
5475   else
5476     {
5477       if (constructor_type != error_mark_node)
5478         warning_init (0, "braces around scalar initializer");
5479       constructor_fields = constructor_type;
5480       constructor_unfilled_fields = constructor_type;
5481     }
5482 }
5483
5484 /* At the end of an implicit or explicit brace level,
5485    finish up that level of constructor.  If a single expression
5486    with redundant braces initialized that level, return the
5487    c_expr structure for that expression.  Otherwise, the original_code
5488    element is set to ERROR_MARK.
5489    If we were outputting the elements as they are read, return 0 as the value
5490    from inner levels (process_init_element ignores that),
5491    but return error_mark_node as the value from the outermost level
5492    (that's what we want to put in DECL_INITIAL).
5493    Otherwise, return a CONSTRUCTOR expression as the value.  */
5494
5495 struct c_expr
5496 pop_init_level (int implicit)
5497 {
5498   struct constructor_stack *p;
5499   struct c_expr ret;
5500   ret.value = 0;
5501   ret.original_code = ERROR_MARK;
5502
5503   if (implicit == 0)
5504     {
5505       /* When we come to an explicit close brace,
5506          pop any inner levels that didn't have explicit braces.  */
5507       while (constructor_stack->implicit)
5508         process_init_element (pop_init_level (1));
5509
5510       gcc_assert (!constructor_range_stack);
5511     }
5512
5513   /* Now output all pending elements.  */
5514   constructor_incremental = 1;
5515   output_pending_init_elements (1);
5516
5517   p = constructor_stack;
5518
5519   /* Error for initializing a flexible array member, or a zero-length
5520      array member in an inappropriate context.  */
5521   if (constructor_type && constructor_fields
5522       && TREE_CODE (constructor_type) == ARRAY_TYPE
5523       && TYPE_DOMAIN (constructor_type)
5524       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5525     {
5526       /* Silently discard empty initializations.  The parser will
5527          already have pedwarned for empty brackets.  */
5528       if (integer_zerop (constructor_unfilled_index))
5529         constructor_type = NULL_TREE;
5530       else
5531         {
5532           gcc_assert (!TYPE_SIZE (constructor_type));
5533
5534           if (constructor_depth > 2)
5535             error_init ("initialization of flexible array member in a nested context");
5536           else if (pedantic)
5537             pedwarn_init ("initialization of a flexible array member");
5538
5539           /* We have already issued an error message for the existence
5540              of a flexible array member not at the end of the structure.
5541              Discard the initializer so that we do not die later.  */
5542           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5543             constructor_type = NULL_TREE;
5544         }
5545     }
5546
5547   /* Warn when some struct elements are implicitly initialized to zero.  */
5548   if (warn_missing_field_initializers
5549       && constructor_type
5550       && TREE_CODE (constructor_type) == RECORD_TYPE
5551       && constructor_unfilled_fields)
5552     {
5553         /* Do not warn for flexible array members or zero-length arrays.  */
5554         while (constructor_unfilled_fields
5555                && (!DECL_SIZE (constructor_unfilled_fields)
5556                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5557           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5558
5559         /* Do not warn if this level of the initializer uses member
5560            designators; it is likely to be deliberate.  */
5561         if (constructor_unfilled_fields && !constructor_designated)
5562           {
5563             push_member_name (constructor_unfilled_fields);
5564             warning_init (OPT_Wmissing_field_initializers,
5565                           "missing initializer");
5566             RESTORE_SPELLING_DEPTH (constructor_depth);
5567           }
5568     }
5569
5570   /* Pad out the end of the structure.  */
5571   if (p->replacement_value.value)
5572     /* If this closes a superfluous brace pair,
5573        just pass out the element between them.  */
5574     ret = p->replacement_value;
5575   else if (constructor_type == 0)
5576     ;
5577   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5578            && TREE_CODE (constructor_type) != UNION_TYPE
5579            && TREE_CODE (constructor_type) != ARRAY_TYPE
5580            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5581     {
5582       /* A nonincremental scalar initializer--just return
5583          the element, after verifying there is just one.  */
5584       if (VEC_empty (constructor_elt,constructor_elements))
5585         {
5586           if (!constructor_erroneous)
5587             error_init ("empty scalar initializer");
5588           ret.value = error_mark_node;
5589         }
5590       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5591         {
5592           error_init ("extra elements in scalar initializer");
5593           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5594         }
5595       else
5596         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5597     }
5598   else
5599     {
5600       if (constructor_erroneous)
5601         ret.value = error_mark_node;
5602       else
5603         {
5604           ret.value = build_constructor (constructor_type,
5605                                          constructor_elements);
5606           if (constructor_constant)
5607             TREE_CONSTANT (ret.value) = 1;
5608           if (constructor_constant && constructor_simple)
5609             TREE_STATIC (ret.value) = 1;
5610         }
5611     }
5612
5613   constructor_type = p->type;
5614   constructor_fields = p->fields;
5615   constructor_index = p->index;
5616   constructor_max_index = p->max_index;
5617   constructor_unfilled_index = p->unfilled_index;
5618   constructor_unfilled_fields = p->unfilled_fields;
5619   constructor_bit_index = p->bit_index;
5620   constructor_elements = p->elements;
5621   constructor_constant = p->constant;
5622   constructor_simple = p->simple;
5623   constructor_erroneous = p->erroneous;
5624   constructor_incremental = p->incremental;
5625   constructor_designated = p->designated;
5626   constructor_pending_elts = p->pending_elts;
5627   constructor_depth = p->depth;
5628   if (!p->implicit)
5629     constructor_range_stack = p->range_stack;
5630   RESTORE_SPELLING_DEPTH (constructor_depth);
5631
5632   constructor_stack = p->next;
5633   free (p);
5634
5635   if (ret.value == 0 && constructor_stack == 0)
5636     ret.value = error_mark_node;
5637   return ret;
5638 }
5639
5640 /* Common handling for both array range and field name designators.
5641    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5642
5643 static int
5644 set_designator (int array)
5645 {
5646   tree subtype;
5647   enum tree_code subcode;
5648
5649   /* Don't die if an entire brace-pair level is superfluous
5650      in the containing level.  */
5651   if (constructor_type == 0)
5652     return 1;
5653
5654   /* If there were errors in this designator list already, bail out
5655      silently.  */
5656   if (designator_erroneous)
5657     return 1;
5658
5659   if (!designator_depth)
5660     {
5661       gcc_assert (!constructor_range_stack);
5662
5663       /* Designator list starts at the level of closest explicit
5664          braces.  */
5665       while (constructor_stack->implicit)
5666         process_init_element (pop_init_level (1));
5667       constructor_designated = 1;
5668       return 0;
5669     }
5670
5671   switch (TREE_CODE (constructor_type))
5672     {
5673     case  RECORD_TYPE:
5674     case  UNION_TYPE:
5675       subtype = TREE_TYPE (constructor_fields);
5676       if (subtype != error_mark_node)
5677         subtype = TYPE_MAIN_VARIANT (subtype);
5678       break;
5679     case ARRAY_TYPE:
5680       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5681       break;
5682     default:
5683       gcc_unreachable ();
5684     }
5685
5686   subcode = TREE_CODE (subtype);
5687   if (array && subcode != ARRAY_TYPE)
5688     {
5689       error_init ("array index in non-array initializer");
5690       return 1;
5691     }
5692   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5693     {
5694       error_init ("field name not in record or union initializer");
5695       return 1;
5696     }
5697
5698   constructor_designated = 1;
5699   push_init_level (2);
5700   return 0;
5701 }
5702
5703 /* If there are range designators in designator list, push a new designator
5704    to constructor_range_stack.  RANGE_END is end of such stack range or
5705    NULL_TREE if there is no range designator at this level.  */
5706
5707 static void
5708 push_range_stack (tree range_end)
5709 {
5710   struct constructor_range_stack *p;
5711
5712   p = GGC_NEW (struct constructor_range_stack);
5713   p->prev = constructor_range_stack;
5714   p->next = 0;
5715   p->fields = constructor_fields;
5716   p->range_start = constructor_index;
5717   p->index = constructor_index;
5718   p->stack = constructor_stack;
5719   p->range_end = range_end;
5720   if (constructor_range_stack)
5721     constructor_range_stack->next = p;
5722   constructor_range_stack = p;
5723 }
5724
5725 /* Within an array initializer, specify the next index to be initialized.
5726    FIRST is that index.  If LAST is nonzero, then initialize a range
5727    of indices, running from FIRST through LAST.  */
5728
5729 void
5730 set_init_index (tree first, tree last)
5731 {
5732   if (set_designator (1))
5733     return;
5734
5735   designator_erroneous = 1;
5736
5737   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5738       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5739     {
5740       error_init ("array index in initializer not of integer type");
5741       return;
5742     }
5743
5744   if (TREE_CODE (first) != INTEGER_CST)
5745     error_init ("nonconstant array index in initializer");
5746   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5747     error_init ("nonconstant array index in initializer");
5748   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5749     error_init ("array index in non-array initializer");
5750   else if (tree_int_cst_sgn (first) == -1)
5751     error_init ("array index in initializer exceeds array bounds");
5752   else if (constructor_max_index
5753            && tree_int_cst_lt (constructor_max_index, first))
5754     error_init ("array index in initializer exceeds array bounds");
5755   else
5756     {
5757       constructor_index = convert (bitsizetype, first);
5758
5759       if (last)
5760         {
5761           if (tree_int_cst_equal (first, last))
5762             last = 0;
5763           else if (tree_int_cst_lt (last, first))
5764             {
5765               error_init ("empty index range in initializer");
5766               last = 0;
5767             }
5768           else
5769             {
5770               last = convert (bitsizetype, last);
5771               if (constructor_max_index != 0
5772                   && tree_int_cst_lt (constructor_max_index, last))
5773                 {
5774                   error_init ("array index range in initializer exceeds array bounds");
5775                   last = 0;
5776                 }
5777             }
5778         }
5779
5780       designator_depth++;
5781       designator_erroneous = 0;
5782       if (constructor_range_stack || last)
5783         push_range_stack (last);
5784     }
5785 }
5786
5787 /* Within a struct initializer, specify the next field to be initialized.  */
5788
5789 void
5790 set_init_label (tree fieldname)
5791 {
5792   tree tail;
5793
5794   if (set_designator (0))
5795     return;
5796
5797   designator_erroneous = 1;
5798
5799   if (TREE_CODE (constructor_type) != RECORD_TYPE
5800       && TREE_CODE (constructor_type) != UNION_TYPE)
5801     {
5802       error_init ("field name not in record or union initializer");
5803       return;
5804     }
5805
5806   for (tail = TYPE_FIELDS (constructor_type); tail;
5807        tail = TREE_CHAIN (tail))
5808     {
5809       if (DECL_NAME (tail) == fieldname)
5810         break;
5811     }
5812
5813   if (tail == 0)
5814     error ("unknown field %qE specified in initializer", fieldname);
5815   else
5816     {
5817       constructor_fields = tail;
5818       designator_depth++;
5819       designator_erroneous = 0;
5820       if (constructor_range_stack)
5821         push_range_stack (NULL_TREE);
5822     }
5823 }
5824 \f
5825 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5826    identifies the initializer, either array index or field in a structure.
5827    VALUE is the value of that index or field.  */
5828
5829 static void
5830 add_pending_init (tree purpose, tree value)
5831 {
5832   struct init_node *p, **q, *r;
5833
5834   q = &constructor_pending_elts;
5835   p = 0;
5836
5837   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5838     {
5839       while (*q != 0)
5840         {
5841           p = *q;
5842           if (tree_int_cst_lt (purpose, p->purpose))
5843             q = &p->left;
5844           else if (tree_int_cst_lt (p->purpose, purpose))
5845             q = &p->right;
5846           else
5847             {
5848               if (TREE_SIDE_EFFECTS (p->value))
5849                 warning_init (0, "initialized field with side-effects overwritten");
5850               else if (warn_override_init)
5851                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5852               p->value = value;
5853               return;
5854             }
5855         }
5856     }
5857   else
5858     {
5859       tree bitpos;
5860
5861       bitpos = bit_position (purpose);
5862       while (*q != NULL)
5863         {
5864           p = *q;
5865           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5866             q = &p->left;
5867           else if (p->purpose != purpose)
5868             q = &p->right;
5869           else
5870             {
5871               if (TREE_SIDE_EFFECTS (p->value))
5872                 warning_init (0, "initialized field with side-effects overwritten");
5873               else if (warn_override_init)
5874                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5875               p->value = value;
5876               return;
5877             }
5878         }
5879     }
5880
5881   r = GGC_NEW (struct init_node);
5882   r->purpose = purpose;
5883   r->value = value;
5884
5885   *q = r;
5886   r->parent = p;
5887   r->left = 0;
5888   r->right = 0;
5889   r->balance = 0;
5890
5891   while (p)
5892     {
5893       struct init_node *s;
5894
5895       if (r == p->left)
5896         {
5897           if (p->balance == 0)
5898             p->balance = -1;
5899           else if (p->balance < 0)
5900             {
5901               if (r->balance < 0)
5902                 {
5903                   /* L rotation.  */
5904                   p->left = r->right;
5905                   if (p->left)
5906                     p->left->parent = p;
5907                   r->right = p;
5908
5909                   p->balance = 0;
5910                   r->balance = 0;
5911
5912                   s = p->parent;
5913                   p->parent = r;
5914                   r->parent = s;
5915                   if (s)
5916                     {
5917                       if (s->left == p)
5918                         s->left = r;
5919                       else
5920                         s->right = r;
5921                     }
5922                   else
5923                     constructor_pending_elts = r;
5924                 }
5925               else
5926                 {
5927                   /* LR rotation.  */
5928                   struct init_node *t = r->right;
5929
5930                   r->right = t->left;
5931                   if (r->right)
5932                     r->right->parent = r;
5933                   t->left = r;
5934
5935                   p->left = t->right;
5936                   if (p->left)
5937                     p->left->parent = p;
5938                   t->right = p;
5939
5940                   p->balance = t->balance < 0;
5941                   r->balance = -(t->balance > 0);
5942                   t->balance = 0;
5943
5944                   s = p->parent;
5945                   p->parent = t;
5946                   r->parent = t;
5947                   t->parent = s;
5948                   if (s)
5949                     {
5950                       if (s->left == p)
5951                         s->left = t;
5952                       else
5953                         s->right = t;
5954                     }
5955                   else
5956                     constructor_pending_elts = t;
5957                 }
5958               break;
5959             }
5960           else
5961             {
5962               /* p->balance == +1; growth of left side balances the node.  */
5963               p->balance = 0;
5964               break;
5965             }
5966         }
5967       else /* r == p->right */
5968         {
5969           if (p->balance == 0)
5970             /* Growth propagation from right side.  */
5971             p->balance++;
5972           else if (p->balance > 0)
5973             {
5974               if (r->balance > 0)
5975                 {
5976                   /* R rotation.  */
5977                   p->right = r->left;
5978                   if (p->right)
5979                     p->right->parent = p;
5980                   r->left = p;
5981
5982                   p->balance = 0;
5983                   r->balance = 0;
5984
5985                   s = p->parent;
5986                   p->parent = r;
5987                   r->parent = s;
5988                   if (s)
5989                     {
5990                       if (s->left == p)
5991                         s->left = r;
5992                       else
5993                         s->right = r;
5994                     }
5995                   else
5996                     constructor_pending_elts = r;
5997                 }
5998               else /* r->balance == -1 */
5999                 {
6000                   /* RL rotation */
6001                   struct init_node *t = r->left;
6002
6003                   r->left = t->right;
6004                   if (r->left)
6005                     r->left->parent = r;
6006                   t->right = r;
6007
6008                   p->right = t->left;
6009                   if (p->right)
6010                     p->right->parent = p;
6011                   t->left = p;
6012
6013                   r->balance = (t->balance < 0);
6014                   p->balance = -(t->balance > 0);
6015                   t->balance = 0;
6016
6017                   s = p->parent;
6018                   p->parent = t;
6019                   r->parent = t;
6020                   t->parent = s;
6021                   if (s)
6022                     {
6023                       if (s->left == p)
6024                         s->left = t;
6025                       else
6026                         s->right = t;
6027                     }
6028                   else
6029                     constructor_pending_elts = t;
6030                 }
6031               break;
6032             }
6033           else
6034             {
6035               /* p->balance == -1; growth of right side balances the node.  */
6036               p->balance = 0;
6037               break;
6038             }
6039         }
6040
6041       r = p;
6042       p = p->parent;
6043     }
6044 }
6045
6046 /* Build AVL tree from a sorted chain.  */
6047
6048 static void
6049 set_nonincremental_init (void)
6050 {
6051   unsigned HOST_WIDE_INT ix;
6052   tree index, value;
6053
6054   if (TREE_CODE (constructor_type) != RECORD_TYPE
6055       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6056     return;
6057
6058   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6059     add_pending_init (index, value);
6060   constructor_elements = 0;
6061   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6062     {
6063       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6064       /* Skip any nameless bit fields at the beginning.  */
6065       while (constructor_unfilled_fields != 0
6066              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6067              && DECL_NAME (constructor_unfilled_fields) == 0)
6068         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6069
6070     }
6071   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6072     {
6073       if (TYPE_DOMAIN (constructor_type))
6074         constructor_unfilled_index
6075             = convert (bitsizetype,
6076                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6077       else
6078         constructor_unfilled_index = bitsize_zero_node;
6079     }
6080   constructor_incremental = 0;
6081 }
6082
6083 /* Build AVL tree from a string constant.  */
6084
6085 static void
6086 set_nonincremental_init_from_string (tree str)
6087 {
6088   tree value, purpose, type;
6089   HOST_WIDE_INT val[2];
6090   const char *p, *end;
6091   int byte, wchar_bytes, charwidth, bitpos;
6092
6093   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6094
6095   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6096       == TYPE_PRECISION (char_type_node))
6097     wchar_bytes = 1;
6098   else
6099     {
6100       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6101                   == TYPE_PRECISION (wchar_type_node));
6102       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6103     }
6104   charwidth = TYPE_PRECISION (char_type_node);
6105   type = TREE_TYPE (constructor_type);
6106   p = TREE_STRING_POINTER (str);
6107   end = p + TREE_STRING_LENGTH (str);
6108
6109   for (purpose = bitsize_zero_node;
6110        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6111        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6112     {
6113       if (wchar_bytes == 1)
6114         {
6115           val[1] = (unsigned char) *p++;
6116           val[0] = 0;
6117         }
6118       else
6119         {
6120           val[0] = 0;
6121           val[1] = 0;
6122           for (byte = 0; byte < wchar_bytes; byte++)
6123             {
6124               if (BYTES_BIG_ENDIAN)
6125                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6126               else
6127                 bitpos = byte * charwidth;
6128               val[bitpos < HOST_BITS_PER_WIDE_INT]
6129                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6130                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6131             }
6132         }
6133
6134       if (!TYPE_UNSIGNED (type))
6135         {
6136           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6137           if (bitpos < HOST_BITS_PER_WIDE_INT)
6138             {
6139               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6140                 {
6141                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6142                   val[0] = -1;
6143                 }
6144             }
6145           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6146             {
6147               if (val[1] < 0)
6148                 val[0] = -1;
6149             }
6150           else if (val[0] & (((HOST_WIDE_INT) 1)
6151                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6152             val[0] |= ((HOST_WIDE_INT) -1)
6153                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6154         }
6155
6156       value = build_int_cst_wide (type, val[1], val[0]);
6157       add_pending_init (purpose, value);
6158     }
6159
6160   constructor_incremental = 0;
6161 }
6162
6163 /* Return value of FIELD in pending initializer or zero if the field was
6164    not initialized yet.  */
6165
6166 static tree
6167 find_init_member (tree field)
6168 {
6169   struct init_node *p;
6170
6171   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6172     {
6173       if (constructor_incremental
6174           && tree_int_cst_lt (field, constructor_unfilled_index))
6175         set_nonincremental_init ();
6176
6177       p = constructor_pending_elts;
6178       while (p)
6179         {
6180           if (tree_int_cst_lt (field, p->purpose))
6181             p = p->left;
6182           else if (tree_int_cst_lt (p->purpose, field))
6183             p = p->right;
6184           else
6185             return p->value;
6186         }
6187     }
6188   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6189     {
6190       tree bitpos = bit_position (field);
6191
6192       if (constructor_incremental
6193           && (!constructor_unfilled_fields
6194               || tree_int_cst_lt (bitpos,
6195                                   bit_position (constructor_unfilled_fields))))
6196         set_nonincremental_init ();
6197
6198       p = constructor_pending_elts;
6199       while (p)
6200         {
6201           if (field == p->purpose)
6202             return p->value;
6203           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6204             p = p->left;
6205           else
6206             p = p->right;
6207         }
6208     }
6209   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6210     {
6211       if (!VEC_empty (constructor_elt, constructor_elements)
6212           && (VEC_last (constructor_elt, constructor_elements)->index
6213               == field))
6214         return VEC_last (constructor_elt, constructor_elements)->value;
6215     }
6216   return 0;
6217 }
6218
6219 /* "Output" the next constructor element.
6220    At top level, really output it to assembler code now.
6221    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6222    TYPE is the data type that the containing data type wants here.
6223    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6224    If VALUE is a string constant, STRICT_STRING is true if it is
6225    unparenthesized or we should not warn here for it being parenthesized.
6226    For other types of VALUE, STRICT_STRING is not used.
6227
6228    PENDING if non-nil means output pending elements that belong
6229    right after this element.  (PENDING is normally 1;
6230    it is 0 while outputting pending elements, to avoid recursion.)  */
6231
6232 static void
6233 output_init_element (tree value, bool strict_string, tree type, tree field,
6234                      int pending)
6235 {
6236   constructor_elt *celt;
6237
6238   if (type == error_mark_node || value == error_mark_node)
6239     {
6240       constructor_erroneous = 1;
6241       return;
6242     }
6243   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6244       && (TREE_CODE (value) == STRING_CST
6245           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6246       && !(TREE_CODE (value) == STRING_CST
6247            && TREE_CODE (type) == ARRAY_TYPE
6248            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6249       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6250                      TYPE_MAIN_VARIANT (type)))
6251     value = array_to_pointer_conversion (value);
6252
6253   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6254       && require_constant_value && !flag_isoc99 && pending)
6255     {
6256       /* As an extension, allow initializing objects with static storage
6257          duration with compound literals (which are then treated just as
6258          the brace enclosed list they contain).  */
6259       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6260       value = DECL_INITIAL (decl);
6261     }
6262
6263   if (value == error_mark_node)
6264     constructor_erroneous = 1;
6265   else if (!TREE_CONSTANT (value))
6266     constructor_constant = 0;
6267   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6268            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6269                 || TREE_CODE (constructor_type) == UNION_TYPE)
6270                && DECL_C_BIT_FIELD (field)
6271                && TREE_CODE (value) != INTEGER_CST))
6272     constructor_simple = 0;
6273
6274   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6275     {
6276       if (require_constant_value)
6277         {
6278           error_init ("initializer element is not constant");
6279           value = error_mark_node;
6280         }
6281       else if (require_constant_elements)
6282         pedwarn ("initializer element is not computable at load time");
6283     }
6284
6285   /* If this field is empty (and not at the end of structure),
6286      don't do anything other than checking the initializer.  */
6287   if (field
6288       && (TREE_TYPE (field) == error_mark_node
6289           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6290               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6291               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6292                   || TREE_CHAIN (field)))))
6293     return;
6294
6295   value = digest_init (type, value, strict_string, require_constant_value);
6296   if (value == error_mark_node)
6297     {
6298       constructor_erroneous = 1;
6299       return;
6300     }
6301
6302   /* If this element doesn't come next in sequence,
6303      put it on constructor_pending_elts.  */
6304   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6305       && (!constructor_incremental
6306           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6307     {
6308       if (constructor_incremental
6309           && tree_int_cst_lt (field, constructor_unfilled_index))
6310         set_nonincremental_init ();
6311
6312       add_pending_init (field, value);
6313       return;
6314     }
6315   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6316            && (!constructor_incremental
6317                || field != constructor_unfilled_fields))
6318     {
6319       /* We do this for records but not for unions.  In a union,
6320          no matter which field is specified, it can be initialized
6321          right away since it starts at the beginning of the union.  */
6322       if (constructor_incremental)
6323         {
6324           if (!constructor_unfilled_fields)
6325             set_nonincremental_init ();
6326           else
6327             {
6328               tree bitpos, unfillpos;
6329
6330               bitpos = bit_position (field);
6331               unfillpos = bit_position (constructor_unfilled_fields);
6332
6333               if (tree_int_cst_lt (bitpos, unfillpos))
6334                 set_nonincremental_init ();
6335             }
6336         }
6337
6338       add_pending_init (field, value);
6339       return;
6340     }
6341   else if (TREE_CODE (constructor_type) == UNION_TYPE
6342            && !VEC_empty (constructor_elt, constructor_elements))
6343     {
6344       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6345                                        constructor_elements)->value))
6346         warning_init (0, "initialized field with side-effects overwritten");
6347       else if (warn_override_init)
6348         warning_init (OPT_Woverride_init, "initialized field overwritten");
6349
6350       /* We can have just one union field set.  */
6351       constructor_elements = 0;
6352     }
6353
6354   /* Otherwise, output this element either to
6355      constructor_elements or to the assembler file.  */
6356
6357   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6358   celt->index = field;
6359   celt->value = value;
6360
6361   /* Advance the variable that indicates sequential elements output.  */
6362   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6363     constructor_unfilled_index
6364       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6365                     bitsize_one_node);
6366   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6367     {
6368       constructor_unfilled_fields
6369         = TREE_CHAIN (constructor_unfilled_fields);
6370
6371       /* Skip any nameless bit fields.  */
6372       while (constructor_unfilled_fields != 0
6373              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6374              && DECL_NAME (constructor_unfilled_fields) == 0)
6375         constructor_unfilled_fields =
6376           TREE_CHAIN (constructor_unfilled_fields);
6377     }
6378   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6379     constructor_unfilled_fields = 0;
6380
6381   /* Now output any pending elements which have become next.  */
6382   if (pending)
6383     output_pending_init_elements (0);
6384 }
6385
6386 /* Output any pending elements which have become next.
6387    As we output elements, constructor_unfilled_{fields,index}
6388    advances, which may cause other elements to become next;
6389    if so, they too are output.
6390
6391    If ALL is 0, we return when there are
6392    no more pending elements to output now.
6393
6394    If ALL is 1, we output space as necessary so that
6395    we can output all the pending elements.  */
6396
6397 static void
6398 output_pending_init_elements (int all)
6399 {
6400   struct init_node *elt = constructor_pending_elts;
6401   tree next;
6402
6403  retry:
6404
6405   /* Look through the whole pending tree.
6406      If we find an element that should be output now,
6407      output it.  Otherwise, set NEXT to the element
6408      that comes first among those still pending.  */
6409
6410   next = 0;
6411   while (elt)
6412     {
6413       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6414         {
6415           if (tree_int_cst_equal (elt->purpose,
6416                                   constructor_unfilled_index))
6417             output_init_element (elt->value, true,
6418                                  TREE_TYPE (constructor_type),
6419                                  constructor_unfilled_index, 0);
6420           else if (tree_int_cst_lt (constructor_unfilled_index,
6421                                     elt->purpose))
6422             {
6423               /* Advance to the next smaller node.  */
6424               if (elt->left)
6425                 elt = elt->left;
6426               else
6427                 {
6428                   /* We have reached the smallest node bigger than the
6429                      current unfilled index.  Fill the space first.  */
6430                   next = elt->purpose;
6431                   break;
6432                 }
6433             }
6434           else
6435             {
6436               /* Advance to the next bigger node.  */
6437               if (elt->right)
6438                 elt = elt->right;
6439               else
6440                 {
6441                   /* We have reached the biggest node in a subtree.  Find
6442                      the parent of it, which is the next bigger node.  */
6443                   while (elt->parent && elt->parent->right == elt)
6444                     elt = elt->parent;
6445                   elt = elt->parent;
6446                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6447                                               elt->purpose))
6448                     {
6449                       next = elt->purpose;
6450                       break;
6451                     }
6452                 }
6453             }
6454         }
6455       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6456                || TREE_CODE (constructor_type) == UNION_TYPE)
6457         {
6458           tree ctor_unfilled_bitpos, elt_bitpos;
6459
6460           /* If the current record is complete we are done.  */
6461           if (constructor_unfilled_fields == 0)
6462             break;
6463
6464           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6465           elt_bitpos = bit_position (elt->purpose);
6466           /* We can't compare fields here because there might be empty
6467              fields in between.  */
6468           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6469             {
6470               constructor_unfilled_fields = elt->purpose;
6471               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6472                                    elt->purpose, 0);
6473             }
6474           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6475             {
6476               /* Advance to the next smaller node.  */
6477               if (elt->left)
6478                 elt = elt->left;
6479               else
6480                 {
6481                   /* We have reached the smallest node bigger than the
6482                      current unfilled field.  Fill the space first.  */
6483                   next = elt->purpose;
6484                   break;
6485                 }
6486             }
6487           else
6488             {
6489               /* Advance to the next bigger node.  */
6490               if (elt->right)
6491                 elt = elt->right;
6492               else
6493                 {
6494                   /* We have reached the biggest node in a subtree.  Find
6495                      the parent of it, which is the next bigger node.  */
6496                   while (elt->parent && elt->parent->right == elt)
6497                     elt = elt->parent;
6498                   elt = elt->parent;
6499                   if (elt
6500                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6501                                            bit_position (elt->purpose))))
6502                     {
6503                       next = elt->purpose;
6504                       break;
6505                     }
6506                 }
6507             }
6508         }
6509     }
6510
6511   /* Ordinarily return, but not if we want to output all
6512      and there are elements left.  */
6513   if (!(all && next != 0))
6514     return;
6515
6516   /* If it's not incremental, just skip over the gap, so that after
6517      jumping to retry we will output the next successive element.  */
6518   if (TREE_CODE (constructor_type) == RECORD_TYPE
6519       || TREE_CODE (constructor_type) == UNION_TYPE)
6520     constructor_unfilled_fields = next;
6521   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6522     constructor_unfilled_index = next;
6523
6524   /* ELT now points to the node in the pending tree with the next
6525      initializer to output.  */
6526   goto retry;
6527 }
6528 \f
6529 /* Add one non-braced element to the current constructor level.
6530    This adjusts the current position within the constructor's type.
6531    This may also start or terminate implicit levels
6532    to handle a partly-braced initializer.
6533
6534    Once this has found the correct level for the new element,
6535    it calls output_init_element.  */
6536
6537 void
6538 process_init_element (struct c_expr value)
6539 {
6540   tree orig_value = value.value;
6541   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6542   bool strict_string = value.original_code == STRING_CST;
6543
6544   designator_depth = 0;
6545   designator_erroneous = 0;
6546
6547   /* Handle superfluous braces around string cst as in
6548      char x[] = {"foo"}; */
6549   if (string_flag
6550       && constructor_type
6551       && TREE_CODE (constructor_type) == ARRAY_TYPE
6552       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6553       && integer_zerop (constructor_unfilled_index))
6554     {
6555       if (constructor_stack->replacement_value.value)
6556         error_init ("excess elements in char array initializer");
6557       constructor_stack->replacement_value = value;
6558       return;
6559     }
6560
6561   if (constructor_stack->replacement_value.value != 0)
6562     {
6563       error_init ("excess elements in struct initializer");
6564       return;
6565     }
6566
6567   /* Ignore elements of a brace group if it is entirely superfluous
6568      and has already been diagnosed.  */
6569   if (constructor_type == 0)
6570     return;
6571
6572   /* If we've exhausted any levels that didn't have braces,
6573      pop them now.  */
6574   while (constructor_stack->implicit)
6575     {
6576       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6577            || TREE_CODE (constructor_type) == UNION_TYPE)
6578           && constructor_fields == 0)
6579         process_init_element (pop_init_level (1));
6580       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6581                && (constructor_max_index == 0
6582                    || tree_int_cst_lt (constructor_max_index,
6583                                        constructor_index)))
6584         process_init_element (pop_init_level (1));
6585       else
6586         break;
6587     }
6588
6589   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6590   if (constructor_range_stack)
6591     {
6592       /* If value is a compound literal and we'll be just using its
6593          content, don't put it into a SAVE_EXPR.  */
6594       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6595           || !require_constant_value
6596           || flag_isoc99)
6597         value.value = save_expr (value.value);
6598     }
6599
6600   while (1)
6601     {
6602       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6603         {
6604           tree fieldtype;
6605           enum tree_code fieldcode;
6606
6607           if (constructor_fields == 0)
6608             {
6609               pedwarn_init ("excess elements in struct initializer");
6610               break;
6611             }
6612
6613           fieldtype = TREE_TYPE (constructor_fields);
6614           if (fieldtype != error_mark_node)
6615             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6616           fieldcode = TREE_CODE (fieldtype);
6617
6618           /* Error for non-static initialization of a flexible array member.  */
6619           if (fieldcode == ARRAY_TYPE
6620               && !require_constant_value
6621               && TYPE_SIZE (fieldtype) == NULL_TREE
6622               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6623             {
6624               error_init ("non-static initialization of a flexible array member");
6625               break;
6626             }
6627
6628           /* Accept a string constant to initialize a subarray.  */
6629           if (value.value != 0
6630               && fieldcode == ARRAY_TYPE
6631               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6632               && string_flag)
6633             value.value = orig_value;
6634           /* Otherwise, if we have come to a subaggregate,
6635              and we don't have an element of its type, push into it.  */
6636           else if (value.value != 0
6637                    && value.value != error_mark_node
6638                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6639                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6640                        || fieldcode == UNION_TYPE))
6641             {
6642               push_init_level (1);
6643               continue;
6644             }
6645
6646           if (value.value)
6647             {
6648               push_member_name (constructor_fields);
6649               output_init_element (value.value, strict_string,
6650                                    fieldtype, constructor_fields, 1);
6651               RESTORE_SPELLING_DEPTH (constructor_depth);
6652             }
6653           else
6654             /* Do the bookkeeping for an element that was
6655                directly output as a constructor.  */
6656             {
6657               /* For a record, keep track of end position of last field.  */
6658               if (DECL_SIZE (constructor_fields))
6659                 constructor_bit_index
6660                   = size_binop (PLUS_EXPR,
6661                                 bit_position (constructor_fields),
6662                                 DECL_SIZE (constructor_fields));
6663
6664               /* If the current field was the first one not yet written out,
6665                  it isn't now, so update.  */
6666               if (constructor_unfilled_fields == constructor_fields)
6667                 {
6668                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6669                   /* Skip any nameless bit fields.  */
6670                   while (constructor_unfilled_fields != 0
6671                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6672                          && DECL_NAME (constructor_unfilled_fields) == 0)
6673                     constructor_unfilled_fields =
6674                       TREE_CHAIN (constructor_unfilled_fields);
6675                 }
6676             }
6677
6678           constructor_fields = TREE_CHAIN (constructor_fields);
6679           /* Skip any nameless bit fields at the beginning.  */
6680           while (constructor_fields != 0
6681                  && DECL_C_BIT_FIELD (constructor_fields)
6682                  && DECL_NAME (constructor_fields) == 0)
6683             constructor_fields = TREE_CHAIN (constructor_fields);
6684         }
6685       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6686         {
6687           tree fieldtype;
6688           enum tree_code fieldcode;
6689
6690           if (constructor_fields == 0)
6691             {
6692               pedwarn_init ("excess elements in union initializer");
6693               break;
6694             }
6695
6696           fieldtype = TREE_TYPE (constructor_fields);
6697           if (fieldtype != error_mark_node)
6698             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6699           fieldcode = TREE_CODE (fieldtype);
6700
6701           /* Warn that traditional C rejects initialization of unions.
6702              We skip the warning if the value is zero.  This is done
6703              under the assumption that the zero initializer in user
6704              code appears conditioned on e.g. __STDC__ to avoid
6705              "missing initializer" warnings and relies on default
6706              initialization to zero in the traditional C case.
6707              We also skip the warning if the initializer is designated,
6708              again on the assumption that this must be conditional on
6709              __STDC__ anyway (and we've already complained about the
6710              member-designator already).  */
6711           if (!in_system_header && !constructor_designated
6712               && !(value.value && (integer_zerop (value.value)
6713                                    || real_zerop (value.value))))
6714             warning (OPT_Wtraditional, "traditional C rejects initialization "
6715                      "of unions");
6716
6717           /* Accept a string constant to initialize a subarray.  */
6718           if (value.value != 0
6719               && fieldcode == ARRAY_TYPE
6720               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6721               && string_flag)
6722             value.value = orig_value;
6723           /* Otherwise, if we have come to a subaggregate,
6724              and we don't have an element of its type, push into it.  */
6725           else if (value.value != 0
6726                    && value.value != error_mark_node
6727                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6728                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6729                        || fieldcode == UNION_TYPE))
6730             {
6731               push_init_level (1);
6732               continue;
6733             }
6734
6735           if (value.value)
6736             {
6737               push_member_name (constructor_fields);
6738               output_init_element (value.value, strict_string,
6739                                    fieldtype, constructor_fields, 1);
6740               RESTORE_SPELLING_DEPTH (constructor_depth);
6741             }
6742           else
6743             /* Do the bookkeeping for an element that was
6744                directly output as a constructor.  */
6745             {
6746               constructor_bit_index = DECL_SIZE (constructor_fields);
6747               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6748             }
6749
6750           constructor_fields = 0;
6751         }
6752       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6753         {
6754           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6755           enum tree_code eltcode = TREE_CODE (elttype);
6756
6757           /* Accept a string constant to initialize a subarray.  */
6758           if (value.value != 0
6759               && eltcode == ARRAY_TYPE
6760               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6761               && string_flag)
6762             value.value = orig_value;
6763           /* Otherwise, if we have come to a subaggregate,
6764              and we don't have an element of its type, push into it.  */
6765           else if (value.value != 0
6766                    && value.value != error_mark_node
6767                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6768                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6769                        || eltcode == UNION_TYPE))
6770             {
6771               push_init_level (1);
6772               continue;
6773             }
6774
6775           if (constructor_max_index != 0
6776               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6777                   || integer_all_onesp (constructor_max_index)))
6778             {
6779               pedwarn_init ("excess elements in array initializer");
6780               break;
6781             }
6782
6783           /* Now output the actual element.  */
6784           if (value.value)
6785             {
6786               push_array_bounds (tree_low_cst (constructor_index, 1));
6787               output_init_element (value.value, strict_string,
6788                                    elttype, constructor_index, 1);
6789               RESTORE_SPELLING_DEPTH (constructor_depth);
6790             }
6791
6792           constructor_index
6793             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6794
6795           if (!value.value)
6796             /* If we are doing the bookkeeping for an element that was
6797                directly output as a constructor, we must update
6798                constructor_unfilled_index.  */
6799             constructor_unfilled_index = constructor_index;
6800         }
6801       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6802         {
6803           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6804
6805          /* Do a basic check of initializer size.  Note that vectors
6806             always have a fixed size derived from their type.  */
6807           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6808             {
6809               pedwarn_init ("excess elements in vector initializer");
6810               break;
6811             }
6812
6813           /* Now output the actual element.  */
6814           if (value.value)
6815             output_init_element (value.value, strict_string,
6816                                  elttype, constructor_index, 1);
6817
6818           constructor_index
6819             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6820
6821           if (!value.value)
6822             /* If we are doing the bookkeeping for an element that was
6823                directly output as a constructor, we must update
6824                constructor_unfilled_index.  */
6825             constructor_unfilled_index = constructor_index;
6826         }
6827
6828       /* Handle the sole element allowed in a braced initializer
6829          for a scalar variable.  */
6830       else if (constructor_type != error_mark_node
6831                && constructor_fields == 0)
6832         {
6833           pedwarn_init ("excess elements in scalar initializer");
6834           break;
6835         }
6836       else
6837         {
6838           if (value.value)
6839             output_init_element (value.value, strict_string,
6840                                  constructor_type, NULL_TREE, 1);
6841           constructor_fields = 0;
6842         }
6843
6844       /* Handle range initializers either at this level or anywhere higher
6845          in the designator stack.  */
6846       if (constructor_range_stack)
6847         {
6848           struct constructor_range_stack *p, *range_stack;
6849           int finish = 0;
6850
6851           range_stack = constructor_range_stack;
6852           constructor_range_stack = 0;
6853           while (constructor_stack != range_stack->stack)
6854             {
6855               gcc_assert (constructor_stack->implicit);
6856               process_init_element (pop_init_level (1));
6857             }
6858           for (p = range_stack;
6859                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6860                p = p->prev)
6861             {
6862               gcc_assert (constructor_stack->implicit);
6863               process_init_element (pop_init_level (1));
6864             }
6865
6866           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6867           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6868             finish = 1;
6869
6870           while (1)
6871             {
6872               constructor_index = p->index;
6873               constructor_fields = p->fields;
6874               if (finish && p->range_end && p->index == p->range_start)
6875                 {
6876                   finish = 0;
6877                   p->prev = 0;
6878                 }
6879               p = p->next;
6880               if (!p)
6881                 break;
6882               push_init_level (2);
6883               p->stack = constructor_stack;
6884               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6885                 p->index = p->range_start;
6886             }
6887
6888           if (!finish)
6889             constructor_range_stack = range_stack;
6890           continue;
6891         }
6892
6893       break;
6894     }
6895
6896   constructor_range_stack = 0;
6897 }
6898 \f
6899 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6900    (guaranteed to be 'volatile' or null) and ARGS (represented using
6901    an ASM_EXPR node).  */
6902 tree
6903 build_asm_stmt (tree cv_qualifier, tree args)
6904 {
6905   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6906     ASM_VOLATILE_P (args) = 1;
6907   return add_stmt (args);
6908 }
6909
6910 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6911    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6912    SIMPLE indicates whether there was anything at all after the
6913    string in the asm expression -- asm("blah") and asm("blah" : )
6914    are subtly different.  We use a ASM_EXPR node to represent this.  */
6915 tree
6916 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6917                 bool simple)
6918 {
6919   tree tail;
6920   tree args;
6921   int i;
6922   const char *constraint;
6923   const char **oconstraints;
6924   bool allows_mem, allows_reg, is_inout;
6925   int ninputs, noutputs;
6926
6927   ninputs = list_length (inputs);
6928   noutputs = list_length (outputs);
6929   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6930
6931   string = resolve_asm_operand_names (string, outputs, inputs);
6932
6933   /* Remove output conversions that change the type but not the mode.  */
6934   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6935     {
6936       tree output = TREE_VALUE (tail);
6937
6938       /* ??? Really, this should not be here.  Users should be using a
6939          proper lvalue, dammit.  But there's a long history of using casts
6940          in the output operands.  In cases like longlong.h, this becomes a
6941          primitive form of typechecking -- if the cast can be removed, then
6942          the output operand had a type of the proper width; otherwise we'll
6943          get an error.  Gross, but ...  */
6944       STRIP_NOPS (output);
6945
6946       if (!lvalue_or_else (output, lv_asm))
6947         output = error_mark_node;
6948
6949       if (output != error_mark_node
6950           && (TREE_READONLY (output)
6951               || TYPE_READONLY (TREE_TYPE (output))
6952               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6953                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6954                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6955         readonly_error (output, lv_asm);
6956
6957       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6958       oconstraints[i] = constraint;
6959
6960       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6961                                    &allows_mem, &allows_reg, &is_inout))
6962         {
6963           /* If the operand is going to end up in memory,
6964              mark it addressable.  */
6965           if (!allows_reg && !c_mark_addressable (output))
6966             output = error_mark_node;
6967         }
6968       else
6969         output = error_mark_node;
6970
6971       TREE_VALUE (tail) = output;
6972     }
6973
6974   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6975     {
6976       tree input;
6977
6978       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6979       input = TREE_VALUE (tail);
6980
6981       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6982                                   oconstraints, &allows_mem, &allows_reg))
6983         {
6984           /* If the operand is going to end up in memory,
6985              mark it addressable.  */
6986           if (!allows_reg && allows_mem)
6987             {
6988               /* Strip the nops as we allow this case.  FIXME, this really
6989                  should be rejected or made deprecated.  */
6990               STRIP_NOPS (input);
6991               if (!c_mark_addressable (input))
6992                 input = error_mark_node;
6993           }
6994         }
6995       else
6996         input = error_mark_node;
6997
6998       TREE_VALUE (tail) = input;
6999     }
7000
7001   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7002
7003   /* asm statements without outputs, including simple ones, are treated
7004      as volatile.  */
7005   ASM_INPUT_P (args) = simple;
7006   ASM_VOLATILE_P (args) = (noutputs == 0);
7007
7008   return args;
7009 }
7010 \f
7011 /* Generate a goto statement to LABEL.  */
7012
7013 tree
7014 c_finish_goto_label (tree label)
7015 {
7016   tree decl = lookup_label (label);
7017   if (!decl)
7018     return NULL_TREE;
7019
7020   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7021     {
7022       error ("jump into statement expression");
7023       return NULL_TREE;
7024     }
7025
7026   if (C_DECL_UNJUMPABLE_VM (decl))
7027     {
7028       error ("jump into scope of identifier with variably modified type");
7029       return NULL_TREE;
7030     }
7031
7032   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7033     {
7034       /* No jump from outside this statement expression context, so
7035          record that there is a jump from within this context.  */
7036       struct c_label_list *nlist;
7037       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7038       nlist->next = label_context_stack_se->labels_used;
7039       nlist->label = decl;
7040       label_context_stack_se->labels_used = nlist;
7041     }
7042
7043   if (!C_DECL_UNDEFINABLE_VM (decl))
7044     {
7045       /* No jump from outside this context context of identifiers with
7046          variably modified type, so record that there is a jump from
7047          within this context.  */
7048       struct c_label_list *nlist;
7049       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7050       nlist->next = label_context_stack_vm->labels_used;
7051       nlist->label = decl;
7052       label_context_stack_vm->labels_used = nlist;
7053     }
7054
7055   TREE_USED (decl) = 1;
7056   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7057 }
7058
7059 /* Generate a computed goto statement to EXPR.  */
7060
7061 tree
7062 c_finish_goto_ptr (tree expr)
7063 {
7064   if (pedantic)
7065     pedwarn ("ISO C forbids %<goto *expr;%>");
7066   expr = convert (ptr_type_node, expr);
7067   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7068 }
7069
7070 /* Generate a C `return' statement.  RETVAL is the expression for what
7071    to return, or a null pointer for `return;' with no value.  */
7072
7073 tree
7074 c_finish_return (tree retval)
7075 {
7076   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7077   bool no_warning = false;
7078
7079   if (TREE_THIS_VOLATILE (current_function_decl))
7080     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7081
7082   if (!retval)
7083     {
7084       current_function_returns_null = 1;
7085       if ((warn_return_type || flag_isoc99)
7086           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7087         {
7088           pedwarn_c99 ("%<return%> with no value, in "
7089                        "function returning non-void");
7090           no_warning = true;
7091         }
7092     }
7093   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7094     {
7095       current_function_returns_null = 1;
7096       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7097         pedwarn ("%<return%> with a value, in function returning void");
7098       else if (pedantic)
7099         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7100     }
7101   else
7102     {
7103       tree t = convert_for_assignment (valtype, retval, ic_return,
7104                                        NULL_TREE, NULL_TREE, 0);
7105       tree res = DECL_RESULT (current_function_decl);
7106       tree inner;
7107
7108       current_function_returns_value = 1;
7109       if (t == error_mark_node)
7110         return NULL_TREE;
7111
7112       inner = t = convert (TREE_TYPE (res), t);
7113
7114       /* Strip any conversions, additions, and subtractions, and see if
7115          we are returning the address of a local variable.  Warn if so.  */
7116       while (1)
7117         {
7118           switch (TREE_CODE (inner))
7119             {
7120             CASE_CONVERT:   case NON_LVALUE_EXPR:
7121             case PLUS_EXPR:
7122               inner = TREE_OPERAND (inner, 0);
7123               continue;
7124
7125             case MINUS_EXPR:
7126               /* If the second operand of the MINUS_EXPR has a pointer
7127                  type (or is converted from it), this may be valid, so
7128                  don't give a warning.  */
7129               {
7130                 tree op1 = TREE_OPERAND (inner, 1);
7131
7132                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7133                        && (CONVERT_EXPR_P (op1)
7134                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7135                   op1 = TREE_OPERAND (op1, 0);
7136
7137                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7138                   break;
7139
7140                 inner = TREE_OPERAND (inner, 0);
7141                 continue;
7142               }
7143
7144             case ADDR_EXPR:
7145               inner = TREE_OPERAND (inner, 0);
7146
7147               while (REFERENCE_CLASS_P (inner)
7148                      && TREE_CODE (inner) != INDIRECT_REF)
7149                 inner = TREE_OPERAND (inner, 0);
7150
7151               if (DECL_P (inner)
7152                   && !DECL_EXTERNAL (inner)
7153                   && !TREE_STATIC (inner)
7154                   && DECL_CONTEXT (inner) == current_function_decl)
7155                 warning (0, "function returns address of local variable");
7156               break;
7157
7158             default:
7159               break;
7160             }
7161
7162           break;
7163         }
7164
7165       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7166     }
7167
7168   ret_stmt = build_stmt (RETURN_EXPR, retval);
7169   TREE_NO_WARNING (ret_stmt) |= no_warning;
7170   return add_stmt (ret_stmt);
7171 }
7172 \f
7173 struct c_switch {
7174   /* The SWITCH_EXPR being built.  */
7175   tree switch_expr;
7176
7177   /* The original type of the testing expression, i.e. before the
7178      default conversion is applied.  */
7179   tree orig_type;
7180
7181   /* A splay-tree mapping the low element of a case range to the high
7182      element, or NULL_TREE if there is no high element.  Used to
7183      determine whether or not a new case label duplicates an old case
7184      label.  We need a tree, rather than simply a hash table, because
7185      of the GNU case range extension.  */
7186   splay_tree cases;
7187
7188   /* Number of nested statement expressions within this switch
7189      statement; if nonzero, case and default labels may not
7190      appear.  */
7191   unsigned int blocked_stmt_expr;
7192
7193   /* Scope of outermost declarations of identifiers with variably
7194      modified type within this switch statement; if nonzero, case and
7195      default labels may not appear.  */
7196   unsigned int blocked_vm;
7197
7198   /* The next node on the stack.  */
7199   struct c_switch *next;
7200 };
7201
7202 /* A stack of the currently active switch statements.  The innermost
7203    switch statement is on the top of the stack.  There is no need to
7204    mark the stack for garbage collection because it is only active
7205    during the processing of the body of a function, and we never
7206    collect at that point.  */
7207
7208 struct c_switch *c_switch_stack;
7209
7210 /* Start a C switch statement, testing expression EXP.  Return the new
7211    SWITCH_EXPR.  */
7212
7213 tree
7214 c_start_case (tree exp)
7215 {
7216   tree orig_type = error_mark_node;
7217   struct c_switch *cs;
7218
7219   if (exp != error_mark_node)
7220     {
7221       orig_type = TREE_TYPE (exp);
7222
7223       if (!INTEGRAL_TYPE_P (orig_type))
7224         {
7225           if (orig_type != error_mark_node)
7226             {
7227               error ("switch quantity not an integer");
7228               orig_type = error_mark_node;
7229             }
7230           exp = integer_zero_node;
7231         }
7232       else
7233         {
7234           tree type = TYPE_MAIN_VARIANT (orig_type);
7235
7236           if (!in_system_header
7237               && (type == long_integer_type_node
7238                   || type == long_unsigned_type_node))
7239             warning (OPT_Wtraditional, "%<long%> switch expression not "
7240                      "converted to %<int%> in ISO C");
7241
7242           exp = default_conversion (exp);
7243         }
7244     }
7245
7246   /* Add this new SWITCH_EXPR to the stack.  */
7247   cs = XNEW (struct c_switch);
7248   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7249   cs->orig_type = orig_type;
7250   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7251   cs->blocked_stmt_expr = 0;
7252   cs->blocked_vm = 0;
7253   cs->next = c_switch_stack;
7254   c_switch_stack = cs;
7255
7256   return add_stmt (cs->switch_expr);
7257 }
7258
7259 /* Process a case label.  */
7260
7261 tree
7262 do_case (tree low_value, tree high_value)
7263 {
7264   tree label = NULL_TREE;
7265
7266   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7267       && !c_switch_stack->blocked_vm)
7268     {
7269       label = c_add_case_label (c_switch_stack->cases,
7270                                 SWITCH_COND (c_switch_stack->switch_expr),
7271                                 c_switch_stack->orig_type,
7272                                 low_value, high_value);
7273       if (label == error_mark_node)
7274         label = NULL_TREE;
7275     }
7276   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7277     {
7278       if (low_value)
7279         error ("case label in statement expression not containing "
7280                "enclosing switch statement");
7281       else
7282         error ("%<default%> label in statement expression not containing "
7283                "enclosing switch statement");
7284     }
7285   else if (c_switch_stack && c_switch_stack->blocked_vm)
7286     {
7287       if (low_value)
7288         error ("case label in scope of identifier with variably modified "
7289                "type not containing enclosing switch statement");
7290       else
7291         error ("%<default%> label in scope of identifier with variably "
7292                "modified type not containing enclosing switch statement");
7293     }
7294   else if (low_value)
7295     error ("case label not within a switch statement");
7296   else
7297     error ("%<default%> label not within a switch statement");
7298
7299   return label;
7300 }
7301
7302 /* Finish the switch statement.  */
7303
7304 void
7305 c_finish_case (tree body)
7306 {
7307   struct c_switch *cs = c_switch_stack;
7308   location_t switch_location;
7309
7310   SWITCH_BODY (cs->switch_expr) = body;
7311
7312   /* We must not be within a statement expression nested in the switch
7313      at this point; we might, however, be within the scope of an
7314      identifier with variably modified type nested in the switch.  */
7315   gcc_assert (!cs->blocked_stmt_expr);
7316
7317   /* Emit warnings as needed.  */
7318   if (EXPR_HAS_LOCATION (cs->switch_expr))
7319     switch_location = EXPR_LOCATION (cs->switch_expr);
7320   else
7321     switch_location = input_location;
7322   c_do_switch_warnings (cs->cases, switch_location,
7323                         TREE_TYPE (cs->switch_expr),
7324                         SWITCH_COND (cs->switch_expr));
7325
7326   /* Pop the stack.  */
7327   c_switch_stack = cs->next;
7328   splay_tree_delete (cs->cases);
7329   XDELETE (cs);
7330 }
7331 \f
7332 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7333    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7334    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7335    statement, and was not surrounded with parenthesis.  */
7336
7337 void
7338 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7339                   tree else_block, bool nested_if)
7340 {
7341   tree stmt;
7342
7343   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7344   if (warn_parentheses && nested_if && else_block == NULL)
7345     {
7346       tree inner_if = then_block;
7347
7348       /* We know from the grammar productions that there is an IF nested
7349          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7350          it might not be exactly THEN_BLOCK, but should be the last
7351          non-container statement within.  */
7352       while (1)
7353         switch (TREE_CODE (inner_if))
7354           {
7355           case COND_EXPR:
7356             goto found;
7357           case BIND_EXPR:
7358             inner_if = BIND_EXPR_BODY (inner_if);
7359             break;
7360           case STATEMENT_LIST:
7361             inner_if = expr_last (then_block);
7362             break;
7363           case TRY_FINALLY_EXPR:
7364           case TRY_CATCH_EXPR:
7365             inner_if = TREE_OPERAND (inner_if, 0);
7366             break;
7367           default:
7368             gcc_unreachable ();
7369           }
7370     found:
7371
7372       if (COND_EXPR_ELSE (inner_if))
7373          warning (OPT_Wparentheses,
7374                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7375                   &if_locus);
7376     }
7377
7378   empty_if_body_warning (then_block, else_block);
7379
7380   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7381   SET_EXPR_LOCATION (stmt, if_locus);
7382   add_stmt (stmt);
7383 }
7384
7385 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7386    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7387    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7388    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7389    the continue label.  Everything is allowed to be NULL.  */
7390
7391 void
7392 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7393                tree blab, tree clab, bool cond_is_first)
7394 {
7395   tree entry = NULL, exit = NULL, t;
7396
7397   /* If the condition is zero don't generate a loop construct.  */
7398   if (cond && integer_zerop (cond))
7399     {
7400       if (cond_is_first)
7401         {
7402           t = build_and_jump (&blab);
7403           SET_EXPR_LOCATION (t, start_locus);
7404           add_stmt (t);
7405         }
7406     }
7407   else
7408     {
7409       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7410
7411       /* If we have an exit condition, then we build an IF with gotos either
7412          out of the loop, or to the top of it.  If there's no exit condition,
7413          then we just build a jump back to the top.  */
7414       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7415
7416       if (cond && !integer_nonzerop (cond))
7417         {
7418           /* Canonicalize the loop condition to the end.  This means
7419              generating a branch to the loop condition.  Reuse the
7420              continue label, if possible.  */
7421           if (cond_is_first)
7422             {
7423               if (incr || !clab)
7424                 {
7425                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7426                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7427                 }
7428               else
7429                 t = build1 (GOTO_EXPR, void_type_node, clab);
7430               SET_EXPR_LOCATION (t, start_locus);
7431               add_stmt (t);
7432             }
7433
7434           t = build_and_jump (&blab);
7435           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7436           if (cond_is_first)
7437             SET_EXPR_LOCATION (exit, start_locus);
7438           else
7439             SET_EXPR_LOCATION (exit, input_location);
7440         }
7441
7442       add_stmt (top);
7443     }
7444
7445   if (body)
7446     add_stmt (body);
7447   if (clab)
7448     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7449   if (incr)
7450     add_stmt (incr);
7451   if (entry)
7452     add_stmt (entry);
7453   if (exit)
7454     add_stmt (exit);
7455   if (blab)
7456     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7457 }
7458
7459 tree
7460 c_finish_bc_stmt (tree *label_p, bool is_break)
7461 {
7462   bool skip;
7463   tree label = *label_p;
7464
7465   /* In switch statements break is sometimes stylistically used after
7466      a return statement.  This can lead to spurious warnings about
7467      control reaching the end of a non-void function when it is
7468      inlined.  Note that we are calling block_may_fallthru with
7469      language specific tree nodes; this works because
7470      block_may_fallthru returns true when given something it does not
7471      understand.  */
7472   skip = !block_may_fallthru (cur_stmt_list);
7473
7474   if (!label)
7475     {
7476       if (!skip)
7477         *label_p = label = create_artificial_label ();
7478     }
7479   else if (TREE_CODE (label) == LABEL_DECL)
7480     ;
7481   else switch (TREE_INT_CST_LOW (label))
7482     {
7483     case 0:
7484       if (is_break)
7485         error ("break statement not within loop or switch");
7486       else
7487         error ("continue statement not within a loop");
7488       return NULL_TREE;
7489
7490     case 1:
7491       gcc_assert (is_break);
7492       error ("break statement used with OpenMP for loop");
7493       return NULL_TREE;
7494
7495     default:
7496       gcc_unreachable ();
7497     }
7498
7499   if (skip)
7500     return NULL_TREE;
7501
7502   if (!is_break)
7503     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7504
7505   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7506 }
7507
7508 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7509
7510 static void
7511 emit_side_effect_warnings (tree expr)
7512 {
7513   if (expr == error_mark_node)
7514     ;
7515   else if (!TREE_SIDE_EFFECTS (expr))
7516     {
7517       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7518         warning (OPT_Wunused_value, "%Hstatement with no effect",
7519                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7520     }
7521   else
7522     warn_if_unused_value (expr, input_location);
7523 }
7524
7525 /* Process an expression as if it were a complete statement.  Emit
7526    diagnostics, but do not call ADD_STMT.  */
7527
7528 tree
7529 c_process_expr_stmt (tree expr)
7530 {
7531   if (!expr)
7532     return NULL_TREE;
7533
7534   if (warn_sequence_point)
7535     verify_sequence_points (expr);
7536
7537   if (TREE_TYPE (expr) != error_mark_node
7538       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7539       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7540     error ("expression statement has incomplete type");
7541
7542   /* If we're not processing a statement expression, warn about unused values.
7543      Warnings for statement expressions will be emitted later, once we figure
7544      out which is the result.  */
7545   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7546       && warn_unused_value)
7547     emit_side_effect_warnings (expr);
7548
7549   /* If the expression is not of a type to which we cannot assign a line
7550      number, wrap the thing in a no-op NOP_EXPR.  */
7551   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7552     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7553
7554   if (CAN_HAVE_LOCATION_P (expr))
7555     SET_EXPR_LOCATION (expr, input_location);
7556
7557   return expr;
7558 }
7559
7560 /* Emit an expression as a statement.  */
7561
7562 tree
7563 c_finish_expr_stmt (tree expr)
7564 {
7565   if (expr)
7566     return add_stmt (c_process_expr_stmt (expr));
7567   else
7568     return NULL;
7569 }
7570
7571 /* Do the opposite and emit a statement as an expression.  To begin,
7572    create a new binding level and return it.  */
7573
7574 tree
7575 c_begin_stmt_expr (void)
7576 {
7577   tree ret;
7578   struct c_label_context_se *nstack;
7579   struct c_label_list *glist;
7580
7581   /* We must force a BLOCK for this level so that, if it is not expanded
7582      later, there is a way to turn off the entire subtree of blocks that
7583      are contained in it.  */
7584   keep_next_level ();
7585   ret = c_begin_compound_stmt (true);
7586   if (c_switch_stack)
7587     {
7588       c_switch_stack->blocked_stmt_expr++;
7589       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7590     }
7591   for (glist = label_context_stack_se->labels_used;
7592        glist != NULL;
7593        glist = glist->next)
7594     {
7595       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7596     }
7597   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7598   nstack->labels_def = NULL;
7599   nstack->labels_used = NULL;
7600   nstack->next = label_context_stack_se;
7601   label_context_stack_se = nstack;
7602
7603   /* Mark the current statement list as belonging to a statement list.  */
7604   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7605
7606   return ret;
7607 }
7608
7609 tree
7610 c_finish_stmt_expr (tree body)
7611 {
7612   tree last, type, tmp, val;
7613   tree *last_p;
7614   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7615
7616   body = c_end_compound_stmt (body, true);
7617   if (c_switch_stack)
7618     {
7619       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7620       c_switch_stack->blocked_stmt_expr--;
7621     }
7622   /* It is no longer possible to jump to labels defined within this
7623      statement expression.  */
7624   for (dlist = label_context_stack_se->labels_def;
7625        dlist != NULL;
7626        dlist = dlist->next)
7627     {
7628       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7629     }
7630   /* It is again possible to define labels with a goto just outside
7631      this statement expression.  */
7632   for (glist = label_context_stack_se->next->labels_used;
7633        glist != NULL;
7634        glist = glist->next)
7635     {
7636       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7637       glist_prev = glist;
7638     }
7639   if (glist_prev != NULL)
7640     glist_prev->next = label_context_stack_se->labels_used;
7641   else
7642     label_context_stack_se->next->labels_used
7643       = label_context_stack_se->labels_used;
7644   label_context_stack_se = label_context_stack_se->next;
7645
7646   /* Locate the last statement in BODY.  See c_end_compound_stmt
7647      about always returning a BIND_EXPR.  */
7648   last_p = &BIND_EXPR_BODY (body);
7649   last = BIND_EXPR_BODY (body);
7650
7651  continue_searching:
7652   if (TREE_CODE (last) == STATEMENT_LIST)
7653     {
7654       tree_stmt_iterator i;
7655
7656       /* This can happen with degenerate cases like ({ }).  No value.  */
7657       if (!TREE_SIDE_EFFECTS (last))
7658         return body;
7659
7660       /* If we're supposed to generate side effects warnings, process
7661          all of the statements except the last.  */
7662       if (warn_unused_value)
7663         {
7664           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7665             emit_side_effect_warnings (tsi_stmt (i));
7666         }
7667       else
7668         i = tsi_last (last);
7669       last_p = tsi_stmt_ptr (i);
7670       last = *last_p;
7671     }
7672
7673   /* If the end of the list is exception related, then the list was split
7674      by a call to push_cleanup.  Continue searching.  */
7675   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7676       || TREE_CODE (last) == TRY_CATCH_EXPR)
7677     {
7678       last_p = &TREE_OPERAND (last, 0);
7679       last = *last_p;
7680       goto continue_searching;
7681     }
7682
7683   /* In the case that the BIND_EXPR is not necessary, return the
7684      expression out from inside it.  */
7685   if (last == error_mark_node
7686       || (last == BIND_EXPR_BODY (body)
7687           && BIND_EXPR_VARS (body) == NULL))
7688     {
7689       /* Do not warn if the return value of a statement expression is
7690          unused.  */
7691       if (CAN_HAVE_LOCATION_P (last))
7692         TREE_NO_WARNING (last) = 1;
7693       return last;
7694     }
7695
7696   /* Extract the type of said expression.  */
7697   type = TREE_TYPE (last);
7698
7699   /* If we're not returning a value at all, then the BIND_EXPR that
7700      we already have is a fine expression to return.  */
7701   if (!type || VOID_TYPE_P (type))
7702     return body;
7703
7704   /* Now that we've located the expression containing the value, it seems
7705      silly to make voidify_wrapper_expr repeat the process.  Create a
7706      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7707   tmp = create_tmp_var_raw (type, NULL);
7708
7709   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7710      tree_expr_nonnegative_p giving up immediately.  */
7711   val = last;
7712   if (TREE_CODE (val) == NOP_EXPR
7713       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7714     val = TREE_OPERAND (val, 0);
7715
7716   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7717   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7718
7719   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7720 }
7721
7722 /* Begin the scope of an identifier of variably modified type, scope
7723    number SCOPE.  Jumping from outside this scope to inside it is not
7724    permitted.  */
7725
7726 void
7727 c_begin_vm_scope (unsigned int scope)
7728 {
7729   struct c_label_context_vm *nstack;
7730   struct c_label_list *glist;
7731
7732   gcc_assert (scope > 0);
7733
7734   /* At file_scope, we don't have to do any processing.  */
7735   if (label_context_stack_vm == NULL)
7736     return;
7737
7738   if (c_switch_stack && !c_switch_stack->blocked_vm)
7739     c_switch_stack->blocked_vm = scope;
7740   for (glist = label_context_stack_vm->labels_used;
7741        glist != NULL;
7742        glist = glist->next)
7743     {
7744       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7745     }
7746   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7747   nstack->labels_def = NULL;
7748   nstack->labels_used = NULL;
7749   nstack->scope = scope;
7750   nstack->next = label_context_stack_vm;
7751   label_context_stack_vm = nstack;
7752 }
7753
7754 /* End a scope which may contain identifiers of variably modified
7755    type, scope number SCOPE.  */
7756
7757 void
7758 c_end_vm_scope (unsigned int scope)
7759 {
7760   if (label_context_stack_vm == NULL)
7761     return;
7762   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7763     c_switch_stack->blocked_vm = 0;
7764   /* We may have a number of nested scopes of identifiers with
7765      variably modified type, all at this depth.  Pop each in turn.  */
7766   while (label_context_stack_vm->scope == scope)
7767     {
7768       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7769
7770       /* It is no longer possible to jump to labels defined within this
7771          scope.  */
7772       for (dlist = label_context_stack_vm->labels_def;
7773            dlist != NULL;
7774            dlist = dlist->next)
7775         {
7776           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7777         }
7778       /* It is again possible to define labels with a goto just outside
7779          this scope.  */
7780       for (glist = label_context_stack_vm->next->labels_used;
7781            glist != NULL;
7782            glist = glist->next)
7783         {
7784           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7785           glist_prev = glist;
7786         }
7787       if (glist_prev != NULL)
7788         glist_prev->next = label_context_stack_vm->labels_used;
7789       else
7790         label_context_stack_vm->next->labels_used
7791           = label_context_stack_vm->labels_used;
7792       label_context_stack_vm = label_context_stack_vm->next;
7793     }
7794 }
7795 \f
7796 /* Begin and end compound statements.  This is as simple as pushing
7797    and popping new statement lists from the tree.  */
7798
7799 tree
7800 c_begin_compound_stmt (bool do_scope)
7801 {
7802   tree stmt = push_stmt_list ();
7803   if (do_scope)
7804     push_scope ();
7805   return stmt;
7806 }
7807
7808 tree
7809 c_end_compound_stmt (tree stmt, bool do_scope)
7810 {
7811   tree block = NULL;
7812
7813   if (do_scope)
7814     {
7815       if (c_dialect_objc ())
7816         objc_clear_super_receiver ();
7817       block = pop_scope ();
7818     }
7819
7820   stmt = pop_stmt_list (stmt);
7821   stmt = c_build_bind_expr (block, stmt);
7822
7823   /* If this compound statement is nested immediately inside a statement
7824      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7825      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7826      STATEMENT_LISTs merge, and thus we can lose track of what statement
7827      was really last.  */
7828   if (cur_stmt_list
7829       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7830       && TREE_CODE (stmt) != BIND_EXPR)
7831     {
7832       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7833       TREE_SIDE_EFFECTS (stmt) = 1;
7834     }
7835
7836   return stmt;
7837 }
7838
7839 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7840    when the current scope is exited.  EH_ONLY is true when this is not
7841    meant to apply to normal control flow transfer.  */
7842
7843 void
7844 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7845 {
7846   enum tree_code code;
7847   tree stmt, list;
7848   bool stmt_expr;
7849
7850   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7851   stmt = build_stmt (code, NULL, cleanup);
7852   add_stmt (stmt);
7853   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7854   list = push_stmt_list ();
7855   TREE_OPERAND (stmt, 0) = list;
7856   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7857 }
7858 \f
7859 /* Build a binary-operation expression without default conversions.
7860    CODE is the kind of expression to build.
7861    This function differs from `build' in several ways:
7862    the data type of the result is computed and recorded in it,
7863    warnings are generated if arg data types are invalid,
7864    special handling for addition and subtraction of pointers is known,
7865    and some optimization is done (operations on narrow ints
7866    are done in the narrower type when that gives the same result).
7867    Constant folding is also done before the result is returned.
7868
7869    Note that the operands will never have enumeral types, or function
7870    or array types, because either they will have the default conversions
7871    performed or they have both just been converted to some other type in which
7872    the arithmetic is to be done.  */
7873
7874 tree
7875 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7876                  int convert_p)
7877 {
7878   tree type0, type1;
7879   enum tree_code code0, code1;
7880   tree op0, op1;
7881   const char *invalid_op_diag;
7882
7883   /* Expression code to give to the expression when it is built.
7884      Normally this is CODE, which is what the caller asked for,
7885      but in some special cases we change it.  */
7886   enum tree_code resultcode = code;
7887
7888   /* Data type in which the computation is to be performed.
7889      In the simplest cases this is the common type of the arguments.  */
7890   tree result_type = NULL;
7891
7892   /* Nonzero means operands have already been type-converted
7893      in whatever way is necessary.
7894      Zero means they need to be converted to RESULT_TYPE.  */
7895   int converted = 0;
7896
7897   /* Nonzero means create the expression with this type, rather than
7898      RESULT_TYPE.  */
7899   tree build_type = 0;
7900
7901   /* Nonzero means after finally constructing the expression
7902      convert it to this type.  */
7903   tree final_type = 0;
7904
7905   /* Nonzero if this is an operation like MIN or MAX which can
7906      safely be computed in short if both args are promoted shorts.
7907      Also implies COMMON.
7908      -1 indicates a bitwise operation; this makes a difference
7909      in the exact conditions for when it is safe to do the operation
7910      in a narrower mode.  */
7911   int shorten = 0;
7912
7913   /* Nonzero if this is a comparison operation;
7914      if both args are promoted shorts, compare the original shorts.
7915      Also implies COMMON.  */
7916   int short_compare = 0;
7917
7918   /* Nonzero if this is a right-shift operation, which can be computed on the
7919      original short and then promoted if the operand is a promoted short.  */
7920   int short_shift = 0;
7921
7922   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7923   int common = 0;
7924
7925   /* True means types are compatible as far as ObjC is concerned.  */
7926   bool objc_ok;
7927
7928   if (convert_p)
7929     {
7930       op0 = default_conversion (orig_op0);
7931       op1 = default_conversion (orig_op1);
7932     }
7933   else
7934     {
7935       op0 = orig_op0;
7936       op1 = orig_op1;
7937     }
7938
7939   type0 = TREE_TYPE (op0);
7940   type1 = TREE_TYPE (op1);
7941
7942   /* The expression codes of the data types of the arguments tell us
7943      whether the arguments are integers, floating, pointers, etc.  */
7944   code0 = TREE_CODE (type0);
7945   code1 = TREE_CODE (type1);
7946
7947   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7948   STRIP_TYPE_NOPS (op0);
7949   STRIP_TYPE_NOPS (op1);
7950
7951   /* If an error was already reported for one of the arguments,
7952      avoid reporting another error.  */
7953
7954   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7955     return error_mark_node;
7956
7957   if ((invalid_op_diag
7958        = targetm.invalid_binary_op (code, type0, type1)))
7959     {
7960       error (invalid_op_diag);
7961       return error_mark_node;
7962     }
7963
7964   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7965
7966   switch (code)
7967     {
7968     case PLUS_EXPR:
7969       /* Handle the pointer + int case.  */
7970       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7971         return pointer_int_sum (PLUS_EXPR, op0, op1);
7972       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7973         return pointer_int_sum (PLUS_EXPR, op1, op0);
7974       else
7975         common = 1;
7976       break;
7977
7978     case MINUS_EXPR:
7979       /* Subtraction of two similar pointers.
7980          We must subtract them as integers, then divide by object size.  */
7981       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7982           && comp_target_types (type0, type1))
7983         return pointer_diff (op0, op1);
7984       /* Handle pointer minus int.  Just like pointer plus int.  */
7985       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7986         return pointer_int_sum (MINUS_EXPR, op0, op1);
7987       else
7988         common = 1;
7989       break;
7990
7991     case MULT_EXPR:
7992       common = 1;
7993       break;
7994
7995     case TRUNC_DIV_EXPR:
7996     case CEIL_DIV_EXPR:
7997     case FLOOR_DIV_EXPR:
7998     case ROUND_DIV_EXPR:
7999     case EXACT_DIV_EXPR:
8000       warn_for_div_by_zero (op1);
8001
8002       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8003            || code0 == FIXED_POINT_TYPE
8004            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8005           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8006               || code1 == FIXED_POINT_TYPE
8007               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8008         {
8009           enum tree_code tcode0 = code0, tcode1 = code1;
8010
8011           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8012             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8013           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8014             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8015
8016           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8017               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8018             resultcode = RDIV_EXPR;
8019           else
8020             /* Although it would be tempting to shorten always here, that
8021                loses on some targets, since the modulo instruction is
8022                undefined if the quotient can't be represented in the
8023                computation mode.  We shorten only if unsigned or if
8024                dividing by something we know != -1.  */
8025             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8026                        || (TREE_CODE (op1) == INTEGER_CST
8027                            && !integer_all_onesp (op1)));
8028           common = 1;
8029         }
8030       break;
8031
8032     case BIT_AND_EXPR:
8033     case BIT_IOR_EXPR:
8034     case BIT_XOR_EXPR:
8035       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8036         shorten = -1;
8037       /* Allow vector types which are not floating point types.   */
8038       else if (code0 == VECTOR_TYPE
8039                && code1 == VECTOR_TYPE
8040                && !VECTOR_FLOAT_TYPE_P (type0)
8041                && !VECTOR_FLOAT_TYPE_P (type1))
8042         common = 1;
8043       break;
8044
8045     case TRUNC_MOD_EXPR:
8046     case FLOOR_MOD_EXPR:
8047       warn_for_div_by_zero (op1);
8048
8049       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8050         {
8051           /* Although it would be tempting to shorten always here, that loses
8052              on some targets, since the modulo instruction is undefined if the
8053              quotient can't be represented in the computation mode.  We shorten
8054              only if unsigned or if dividing by something we know != -1.  */
8055           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8056                      || (TREE_CODE (op1) == INTEGER_CST
8057                          && !integer_all_onesp (op1)));
8058           common = 1;
8059         }
8060       break;
8061
8062     case TRUTH_ANDIF_EXPR:
8063     case TRUTH_ORIF_EXPR:
8064     case TRUTH_AND_EXPR:
8065     case TRUTH_OR_EXPR:
8066     case TRUTH_XOR_EXPR:
8067       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8068            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8069            || code0 == FIXED_POINT_TYPE)
8070           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8071               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8072               || code1 == FIXED_POINT_TYPE))
8073         {
8074           /* Result of these operations is always an int,
8075              but that does not mean the operands should be
8076              converted to ints!  */
8077           result_type = integer_type_node;
8078           op0 = c_common_truthvalue_conversion (op0);
8079           op1 = c_common_truthvalue_conversion (op1);
8080           converted = 1;
8081         }
8082       break;
8083
8084       /* Shift operations: result has same type as first operand;
8085          always convert second operand to int.
8086          Also set SHORT_SHIFT if shifting rightward.  */
8087
8088     case RSHIFT_EXPR:
8089       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8090           && code1 == INTEGER_TYPE)
8091         {
8092           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8093             {
8094               if (tree_int_cst_sgn (op1) < 0)
8095                 warning (0, "right shift count is negative");
8096               else
8097                 {
8098                   if (!integer_zerop (op1))
8099                     short_shift = 1;
8100
8101                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8102                     warning (0, "right shift count >= width of type");
8103                 }
8104             }
8105
8106           /* Use the type of the value to be shifted.  */
8107           result_type = type0;
8108           /* Convert the shift-count to an integer, regardless of size
8109              of value being shifted.  */
8110           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8111             op1 = convert (integer_type_node, op1);
8112           /* Avoid converting op1 to result_type later.  */
8113           converted = 1;
8114         }
8115       break;
8116
8117     case LSHIFT_EXPR:
8118       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8119           && code1 == INTEGER_TYPE)
8120         {
8121           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8122             {
8123               if (tree_int_cst_sgn (op1) < 0)
8124                 warning (0, "left shift count is negative");
8125
8126               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8127                 warning (0, "left shift count >= width of type");
8128             }
8129
8130           /* Use the type of the value to be shifted.  */
8131           result_type = type0;
8132           /* Convert the shift-count to an integer, regardless of size
8133              of value being shifted.  */
8134           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8135             op1 = convert (integer_type_node, op1);
8136           /* Avoid converting op1 to result_type later.  */
8137           converted = 1;
8138         }
8139       break;
8140
8141     case EQ_EXPR:
8142     case NE_EXPR:
8143       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8144         warning (OPT_Wfloat_equal,
8145                  "comparing floating point with == or != is unsafe");
8146       /* Result of comparison is always int,
8147          but don't convert the args to int!  */
8148       build_type = integer_type_node;
8149       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8150            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8151           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8152               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8153         short_compare = 1;
8154       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8155         {
8156           tree tt0 = TREE_TYPE (type0);
8157           tree tt1 = TREE_TYPE (type1);
8158           /* Anything compares with void *.  void * compares with anything.
8159              Otherwise, the targets must be compatible
8160              and both must be object or both incomplete.  */
8161           if (comp_target_types (type0, type1))
8162             result_type = common_pointer_type (type0, type1);
8163           else if (VOID_TYPE_P (tt0))
8164             {
8165               /* op0 != orig_op0 detects the case of something
8166                  whose value is 0 but which isn't a valid null ptr const.  */
8167               if (pedantic && !null_pointer_constant_p (orig_op0)
8168                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8169                 pedwarn ("ISO C forbids comparison of %<void *%>"
8170                          " with function pointer");
8171             }
8172           else if (VOID_TYPE_P (tt1))
8173             {
8174               if (pedantic && !null_pointer_constant_p (orig_op1)
8175                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8176                 pedwarn ("ISO C forbids comparison of %<void *%>"
8177                          " with function pointer");
8178             }
8179           else
8180             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8181             if (!objc_ok)
8182               pedwarn ("comparison of distinct pointer types lacks a cast");
8183
8184           if (result_type == NULL_TREE)
8185             result_type = ptr_type_node;
8186         }
8187       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8188         {
8189           if (TREE_CODE (op0) == ADDR_EXPR
8190               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8191             warning (OPT_Waddress, "the address of %qD will never be NULL",
8192                      TREE_OPERAND (op0, 0));
8193           result_type = type0;
8194         }
8195       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8196         {
8197           if (TREE_CODE (op1) == ADDR_EXPR
8198               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8199             warning (OPT_Waddress, "the address of %qD will never be NULL",
8200                      TREE_OPERAND (op1, 0));
8201           result_type = type1;
8202         }
8203       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8204         {
8205           result_type = type0;
8206           pedwarn ("comparison between pointer and integer");
8207         }
8208       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8209         {
8210           result_type = type1;
8211           pedwarn ("comparison between pointer and integer");
8212         }
8213       break;
8214
8215     case LE_EXPR:
8216     case GE_EXPR:
8217     case LT_EXPR:
8218     case GT_EXPR:
8219       build_type = integer_type_node;
8220       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8221            || code0 == FIXED_POINT_TYPE)
8222           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8223               || code1 == FIXED_POINT_TYPE))
8224         short_compare = 1;
8225       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8226         {
8227           if (comp_target_types (type0, type1))
8228             {
8229               result_type = common_pointer_type (type0, type1);
8230               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8231                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8232                 pedwarn ("comparison of complete and incomplete pointers");
8233               else if (pedantic
8234                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8235                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8236             }
8237           else
8238             {
8239               result_type = ptr_type_node;
8240               pedwarn ("comparison of distinct pointer types lacks a cast");
8241             }
8242         }
8243       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8244         {
8245           result_type = type0;
8246           if (pedantic || extra_warnings)
8247             pedwarn ("ordered comparison of pointer with integer zero");
8248         }
8249       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8250         {
8251           result_type = type1;
8252           if (pedantic)
8253             pedwarn ("ordered comparison of pointer with integer zero");
8254         }
8255       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8256         {
8257           result_type = type0;
8258           pedwarn ("comparison between pointer and integer");
8259         }
8260       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8261         {
8262           result_type = type1;
8263           pedwarn ("comparison between pointer and integer");
8264         }
8265       break;
8266
8267     default:
8268       gcc_unreachable ();
8269     }
8270
8271   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8272     return error_mark_node;
8273
8274   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8275       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8276           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8277                                                     TREE_TYPE (type1))))
8278     {
8279       binary_op_error (code, type0, type1);
8280       return error_mark_node;
8281     }
8282
8283   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8284        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8285       &&
8286       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8287        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8288     {
8289       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8290
8291       if (shorten || common || short_compare)
8292         {
8293           result_type = c_common_type (type0, type1);
8294           if (result_type == error_mark_node)
8295             return error_mark_node;
8296         }
8297
8298       /* For certain operations (which identify themselves by shorten != 0)
8299          if both args were extended from the same smaller type,
8300          do the arithmetic in that type and then extend.
8301
8302          shorten !=0 and !=1 indicates a bitwise operation.
8303          For them, this optimization is safe only if
8304          both args are zero-extended or both are sign-extended.
8305          Otherwise, we might change the result.
8306          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8307          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8308
8309       if (shorten && none_complex)
8310         {
8311           int unsigned0, unsigned1;
8312           tree arg0, arg1;
8313           int uns;
8314           tree type;
8315
8316           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8317              excessive narrowing when we call get_narrower below.  For
8318              example, suppose that OP0 is of unsigned int extended
8319              from signed char and that RESULT_TYPE is long long int.
8320              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8321              like
8322
8323                (long long int) (unsigned int) signed_char
8324
8325              which get_narrower would narrow down to
8326
8327                (unsigned int) signed char
8328
8329              If we do not cast OP0 first, get_narrower would return
8330              signed_char, which is inconsistent with the case of the
8331              explicit cast.  */
8332           op0 = convert (result_type, op0);
8333           op1 = convert (result_type, op1);
8334
8335           arg0 = get_narrower (op0, &unsigned0);
8336           arg1 = get_narrower (op1, &unsigned1);
8337
8338           /* UNS is 1 if the operation to be done is an unsigned one.  */
8339           uns = TYPE_UNSIGNED (result_type);
8340
8341           final_type = result_type;
8342
8343           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8344              but it *requires* conversion to FINAL_TYPE.  */
8345
8346           if ((TYPE_PRECISION (TREE_TYPE (op0))
8347                == TYPE_PRECISION (TREE_TYPE (arg0)))
8348               && TREE_TYPE (op0) != final_type)
8349             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8350           if ((TYPE_PRECISION (TREE_TYPE (op1))
8351                == TYPE_PRECISION (TREE_TYPE (arg1)))
8352               && TREE_TYPE (op1) != final_type)
8353             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8354
8355           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8356
8357           /* For bitwise operations, signedness of nominal type
8358              does not matter.  Consider only how operands were extended.  */
8359           if (shorten == -1)
8360             uns = unsigned0;
8361
8362           /* Note that in all three cases below we refrain from optimizing
8363              an unsigned operation on sign-extended args.
8364              That would not be valid.  */
8365
8366           /* Both args variable: if both extended in same way
8367              from same width, do it in that width.
8368              Do it unsigned if args were zero-extended.  */
8369           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8370                < TYPE_PRECISION (result_type))
8371               && (TYPE_PRECISION (TREE_TYPE (arg1))
8372                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8373               && unsigned0 == unsigned1
8374               && (unsigned0 || !uns))
8375             result_type
8376               = c_common_signed_or_unsigned_type
8377               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8378           else if (TREE_CODE (arg0) == INTEGER_CST
8379                    && (unsigned1 || !uns)
8380                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8381                        < TYPE_PRECISION (result_type))
8382                    && (type
8383                        = c_common_signed_or_unsigned_type (unsigned1,
8384                                                            TREE_TYPE (arg1)))
8385                    && !POINTER_TYPE_P (type)
8386                    && int_fits_type_p (arg0, type))
8387             result_type = type;
8388           else if (TREE_CODE (arg1) == INTEGER_CST
8389                    && (unsigned0 || !uns)
8390                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8391                        < TYPE_PRECISION (result_type))
8392                    && (type
8393                        = c_common_signed_or_unsigned_type (unsigned0,
8394                                                            TREE_TYPE (arg0)))
8395                    && !POINTER_TYPE_P (type)
8396                    && int_fits_type_p (arg1, type))
8397             result_type = type;
8398         }
8399
8400       /* Shifts can be shortened if shifting right.  */
8401
8402       if (short_shift)
8403         {
8404           int unsigned_arg;
8405           tree arg0 = get_narrower (op0, &unsigned_arg);
8406
8407           final_type = result_type;
8408
8409           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8410             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8411
8412           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8413               /* We can shorten only if the shift count is less than the
8414                  number of bits in the smaller type size.  */
8415               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8416               /* We cannot drop an unsigned shift after sign-extension.  */
8417               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8418             {
8419               /* Do an unsigned shift if the operand was zero-extended.  */
8420               result_type
8421                 = c_common_signed_or_unsigned_type (unsigned_arg,
8422                                                     TREE_TYPE (arg0));
8423               /* Convert value-to-be-shifted to that type.  */
8424               if (TREE_TYPE (op0) != result_type)
8425                 op0 = convert (result_type, op0);
8426               converted = 1;
8427             }
8428         }
8429
8430       /* Comparison operations are shortened too but differently.
8431          They identify themselves by setting short_compare = 1.  */
8432
8433       if (short_compare)
8434         {
8435           /* Don't write &op0, etc., because that would prevent op0
8436              from being kept in a register.
8437              Instead, make copies of the our local variables and
8438              pass the copies by reference, then copy them back afterward.  */
8439           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8440           enum tree_code xresultcode = resultcode;
8441           tree val
8442             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8443
8444           if (val != 0)
8445             return val;
8446
8447           op0 = xop0, op1 = xop1;
8448           converted = 1;
8449           resultcode = xresultcode;
8450
8451           if (warn_sign_compare && skip_evaluation == 0)
8452             {
8453               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8454               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8455               int unsignedp0, unsignedp1;
8456               tree primop0 = get_narrower (op0, &unsignedp0);
8457               tree primop1 = get_narrower (op1, &unsignedp1);
8458
8459               xop0 = orig_op0;
8460               xop1 = orig_op1;
8461               STRIP_TYPE_NOPS (xop0);
8462               STRIP_TYPE_NOPS (xop1);
8463
8464               /* Give warnings for comparisons between signed and unsigned
8465                  quantities that may fail.
8466
8467                  Do the checking based on the original operand trees, so that
8468                  casts will be considered, but default promotions won't be.
8469
8470                  Do not warn if the comparison is being done in a signed type,
8471                  since the signed type will only be chosen if it can represent
8472                  all the values of the unsigned type.  */
8473               if (!TYPE_UNSIGNED (result_type))
8474                 /* OK */;
8475               /* Do not warn if both operands are the same signedness.  */
8476               else if (op0_signed == op1_signed)
8477                 /* OK */;
8478               else
8479                 {
8480                   tree sop, uop;
8481                   bool ovf;
8482
8483                   if (op0_signed)
8484                     sop = xop0, uop = xop1;
8485                   else
8486                     sop = xop1, uop = xop0;
8487
8488                   /* Do not warn if the signed quantity is an
8489                      unsuffixed integer literal (or some static
8490                      constant expression involving such literals or a
8491                      conditional expression involving such literals)
8492                      and it is non-negative.  */
8493                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8494                     /* OK */;
8495                   /* Do not warn if the comparison is an equality operation,
8496                      the unsigned quantity is an integral constant, and it
8497                      would fit in the result if the result were signed.  */
8498                   else if (TREE_CODE (uop) == INTEGER_CST
8499                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8500                            && int_fits_type_p
8501                            (uop, c_common_signed_type (result_type)))
8502                     /* OK */;
8503                   /* Do not warn if the unsigned quantity is an enumeration
8504                      constant and its maximum value would fit in the result
8505                      if the result were signed.  */
8506                   else if (TREE_CODE (uop) == INTEGER_CST
8507                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8508                            && int_fits_type_p
8509                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8510                             c_common_signed_type (result_type)))
8511                     /* OK */;
8512                   else
8513                     warning (OPT_Wsign_compare, "comparison between signed and unsigned");
8514                 }
8515
8516               /* Warn if two unsigned values are being compared in a size
8517                  larger than their original size, and one (and only one) is the
8518                  result of a `~' operator.  This comparison will always fail.
8519
8520                  Also warn if one operand is a constant, and the constant
8521                  does not have all bits set that are set in the ~ operand
8522                  when it is extended.  */
8523
8524               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8525                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8526                 {
8527                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8528                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8529                                             &unsignedp0);
8530                   else
8531                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8532                                             &unsignedp1);
8533
8534                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8535                     {
8536                       tree primop;
8537                       HOST_WIDE_INT constant, mask;
8538                       int unsignedp, bits;
8539
8540                       if (host_integerp (primop0, 0))
8541                         {
8542                           primop = primop1;
8543                           unsignedp = unsignedp1;
8544                           constant = tree_low_cst (primop0, 0);
8545                         }
8546                       else
8547                         {
8548                           primop = primop0;
8549                           unsignedp = unsignedp0;
8550                           constant = tree_low_cst (primop1, 0);
8551                         }
8552
8553                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8554                       if (bits < TYPE_PRECISION (result_type)
8555                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8556                         {
8557                           mask = (~(HOST_WIDE_INT) 0) << bits;
8558                           if ((mask & constant) != mask)
8559                             warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with constant");
8560                         }
8561                     }
8562                   else if (unsignedp0 && unsignedp1
8563                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8564                                < TYPE_PRECISION (result_type))
8565                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8566                                < TYPE_PRECISION (result_type)))
8567                     warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with unsigned");
8568                 }
8569             }
8570         }
8571     }
8572
8573   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8574      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8575      Then the expression will be built.
8576      It will be given type FINAL_TYPE if that is nonzero;
8577      otherwise, it will be given type RESULT_TYPE.  */
8578
8579   if (!result_type)
8580     {
8581       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8582       return error_mark_node;
8583     }
8584
8585   if (!converted)
8586     {
8587       if (TREE_TYPE (op0) != result_type)
8588         op0 = convert_and_check (result_type, op0);
8589       if (TREE_TYPE (op1) != result_type)
8590         op1 = convert_and_check (result_type, op1);
8591
8592       /* This can happen if one operand has a vector type, and the other
8593          has a different type.  */
8594       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8595         return error_mark_node;
8596     }
8597
8598   if (build_type == NULL_TREE)
8599     build_type = result_type;
8600
8601   {
8602     /* Treat expressions in initializers specially as they can't trap.  */
8603     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8604                                                                     build_type,
8605                                                                     op0, op1)
8606                                          : fold_build2 (resultcode, build_type,
8607                                                         op0, op1);
8608
8609     if (final_type != 0)
8610       result = convert (final_type, result);
8611     return result;
8612   }
8613 }
8614
8615
8616 /* Convert EXPR to be a truth-value, validating its type for this
8617    purpose.  */
8618
8619 tree
8620 c_objc_common_truthvalue_conversion (tree expr)
8621 {
8622   switch (TREE_CODE (TREE_TYPE (expr)))
8623     {
8624     case ARRAY_TYPE:
8625       error ("used array that cannot be converted to pointer where scalar is required");
8626       return error_mark_node;
8627
8628     case RECORD_TYPE:
8629       error ("used struct type value where scalar is required");
8630       return error_mark_node;
8631
8632     case UNION_TYPE:
8633       error ("used union type value where scalar is required");
8634       return error_mark_node;
8635
8636     case FUNCTION_TYPE:
8637       gcc_unreachable ();
8638
8639     default:
8640       break;
8641     }
8642
8643   /* ??? Should we also give an error for void and vectors rather than
8644      leaving those to give errors later?  */
8645   return c_common_truthvalue_conversion (expr);
8646 }
8647 \f
8648
8649 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8650    required.  */
8651
8652 tree
8653 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8654 {
8655   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8656     {
8657       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8658       /* Executing a compound literal inside a function reinitializes
8659          it.  */
8660       if (!TREE_STATIC (decl))
8661         *se = true;
8662       return decl;
8663     }
8664   else
8665     return expr;
8666 }
8667 \f
8668 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8669
8670 tree
8671 c_begin_omp_parallel (void)
8672 {
8673   tree block;
8674
8675   keep_next_level ();
8676   block = c_begin_compound_stmt (true);
8677
8678   return block;
8679 }
8680
8681 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8682
8683 tree
8684 c_finish_omp_parallel (tree clauses, tree block)
8685 {
8686   tree stmt;
8687
8688   block = c_end_compound_stmt (block, true);
8689
8690   stmt = make_node (OMP_PARALLEL);
8691   TREE_TYPE (stmt) = void_type_node;
8692   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8693   OMP_PARALLEL_BODY (stmt) = block;
8694
8695   return add_stmt (stmt);
8696 }
8697
8698 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8699
8700 tree
8701 c_begin_omp_task (void)
8702 {
8703   tree block;
8704
8705   keep_next_level ();
8706   block = c_begin_compound_stmt (true);
8707
8708   return block;
8709 }
8710
8711 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8712
8713 tree
8714 c_finish_omp_task (tree clauses, tree block)
8715 {
8716   tree stmt;
8717
8718   block = c_end_compound_stmt (block, true);
8719
8720   stmt = make_node (OMP_TASK);
8721   TREE_TYPE (stmt) = void_type_node;
8722   OMP_TASK_CLAUSES (stmt) = clauses;
8723   OMP_TASK_BODY (stmt) = block;
8724
8725   return add_stmt (stmt);
8726 }
8727
8728 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8729    Remove any elements from the list that are invalid.  */
8730
8731 tree
8732 c_finish_omp_clauses (tree clauses)
8733 {
8734   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8735   tree c, t, *pc = &clauses;
8736   const char *name;
8737
8738   bitmap_obstack_initialize (NULL);
8739   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8740   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8741   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8742
8743   for (pc = &clauses, c = clauses; c ; c = *pc)
8744     {
8745       bool remove = false;
8746       bool need_complete = false;
8747       bool need_implicitly_determined = false;
8748
8749       switch (OMP_CLAUSE_CODE (c))
8750         {
8751         case OMP_CLAUSE_SHARED:
8752           name = "shared";
8753           need_implicitly_determined = true;
8754           goto check_dup_generic;
8755
8756         case OMP_CLAUSE_PRIVATE:
8757           name = "private";
8758           need_complete = true;
8759           need_implicitly_determined = true;
8760           goto check_dup_generic;
8761
8762         case OMP_CLAUSE_REDUCTION:
8763           name = "reduction";
8764           need_implicitly_determined = true;
8765           t = OMP_CLAUSE_DECL (c);
8766           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8767               || POINTER_TYPE_P (TREE_TYPE (t)))
8768             {
8769               error ("%qE has invalid type for %<reduction%>", t);
8770               remove = true;
8771             }
8772           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8773             {
8774               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8775               const char *r_name = NULL;
8776
8777               switch (r_code)
8778                 {
8779                 case PLUS_EXPR:
8780                 case MULT_EXPR:
8781                 case MINUS_EXPR:
8782                   break;
8783                 case BIT_AND_EXPR:
8784                   r_name = "&";
8785                   break;
8786                 case BIT_XOR_EXPR:
8787                   r_name = "^";
8788                   break;
8789                 case BIT_IOR_EXPR:
8790                   r_name = "|";
8791                   break;
8792                 case TRUTH_ANDIF_EXPR:
8793                   r_name = "&&";
8794                   break;
8795                 case TRUTH_ORIF_EXPR:
8796                   r_name = "||";
8797                   break;
8798                 default:
8799                   gcc_unreachable ();
8800                 }
8801               if (r_name)
8802                 {
8803                   error ("%qE has invalid type for %<reduction(%s)%>",
8804                          t, r_name);
8805                   remove = true;
8806                 }
8807             }
8808           goto check_dup_generic;
8809
8810         case OMP_CLAUSE_COPYPRIVATE:
8811           name = "copyprivate";
8812           goto check_dup_generic;
8813
8814         case OMP_CLAUSE_COPYIN:
8815           name = "copyin";
8816           t = OMP_CLAUSE_DECL (c);
8817           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8818             {
8819               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8820               remove = true;
8821             }
8822           goto check_dup_generic;
8823
8824         check_dup_generic:
8825           t = OMP_CLAUSE_DECL (c);
8826           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8827             {
8828               error ("%qE is not a variable in clause %qs", t, name);
8829               remove = true;
8830             }
8831           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8832                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8833                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8834             {
8835               error ("%qE appears more than once in data clauses", t);
8836               remove = true;
8837             }
8838           else
8839             bitmap_set_bit (&generic_head, DECL_UID (t));
8840           break;
8841
8842         case OMP_CLAUSE_FIRSTPRIVATE:
8843           name = "firstprivate";
8844           t = OMP_CLAUSE_DECL (c);
8845           need_complete = true;
8846           need_implicitly_determined = true;
8847           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8848             {
8849               error ("%qE is not a variable in clause %<firstprivate%>", t);
8850               remove = true;
8851             }
8852           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8853                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8854             {
8855               error ("%qE appears more than once in data clauses", t);
8856               remove = true;
8857             }
8858           else
8859             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8860           break;
8861
8862         case OMP_CLAUSE_LASTPRIVATE:
8863           name = "lastprivate";
8864           t = OMP_CLAUSE_DECL (c);
8865           need_complete = true;
8866           need_implicitly_determined = true;
8867           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8868             {
8869               error ("%qE is not a variable in clause %<lastprivate%>", t);
8870               remove = true;
8871             }
8872           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8873                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8874             {
8875               error ("%qE appears more than once in data clauses", t);
8876               remove = true;
8877             }
8878           else
8879             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8880           break;
8881
8882         case OMP_CLAUSE_IF:
8883         case OMP_CLAUSE_NUM_THREADS:
8884         case OMP_CLAUSE_SCHEDULE:
8885         case OMP_CLAUSE_NOWAIT:
8886         case OMP_CLAUSE_ORDERED:
8887         case OMP_CLAUSE_DEFAULT:
8888         case OMP_CLAUSE_UNTIED:
8889         case OMP_CLAUSE_COLLAPSE:
8890           pc = &OMP_CLAUSE_CHAIN (c);
8891           continue;
8892
8893         default:
8894           gcc_unreachable ();
8895         }
8896
8897       if (!remove)
8898         {
8899           t = OMP_CLAUSE_DECL (c);
8900
8901           if (need_complete)
8902             {
8903               t = require_complete_type (t);
8904               if (t == error_mark_node)
8905                 remove = true;
8906             }
8907
8908           if (need_implicitly_determined)
8909             {
8910               const char *share_name = NULL;
8911
8912               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8913                 share_name = "threadprivate";
8914               else switch (c_omp_predetermined_sharing (t))
8915                 {
8916                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8917                   break;
8918                 case OMP_CLAUSE_DEFAULT_SHARED:
8919                   share_name = "shared";
8920                   break;
8921                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8922                   share_name = "private";
8923                   break;
8924                 default:
8925                   gcc_unreachable ();
8926                 }
8927               if (share_name)
8928                 {
8929                   error ("%qE is predetermined %qs for %qs",
8930                          t, share_name, name);
8931                   remove = true;
8932                 }
8933             }
8934         }
8935
8936       if (remove)
8937         *pc = OMP_CLAUSE_CHAIN (c);
8938       else
8939         pc = &OMP_CLAUSE_CHAIN (c);
8940     }
8941
8942   bitmap_obstack_release (NULL);
8943   return clauses;
8944 }
8945
8946 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8947    down to the element type of an array.  */
8948
8949 tree
8950 c_build_qualified_type (tree type, int type_quals)
8951 {
8952   if (type == error_mark_node)
8953     return type;
8954
8955   if (TREE_CODE (type) == ARRAY_TYPE)
8956     {
8957       tree t;
8958       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8959                                                   type_quals);
8960
8961       /* See if we already have an identically qualified type.  */
8962       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8963         {
8964           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8965               && TYPE_NAME (t) == TYPE_NAME (type)
8966               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8967               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8968                                        TYPE_ATTRIBUTES (type)))
8969             break;
8970         }
8971       if (!t)
8972         {
8973           tree domain = TYPE_DOMAIN (type);
8974
8975           t = build_variant_type_copy (type);
8976           TREE_TYPE (t) = element_type;
8977
8978           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8979               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8980             SET_TYPE_STRUCTURAL_EQUALITY (t);
8981           else if (TYPE_CANONICAL (element_type) != element_type
8982                    || (domain && TYPE_CANONICAL (domain) != domain))
8983             {
8984               tree unqualified_canon
8985                 = build_array_type (TYPE_CANONICAL (element_type),
8986                                     domain? TYPE_CANONICAL (domain)
8987                                           : NULL_TREE);
8988               TYPE_CANONICAL (t)
8989                 = c_build_qualified_type (unqualified_canon, type_quals);
8990             }
8991           else
8992             TYPE_CANONICAL (t) = t;
8993         }
8994       return t;
8995     }
8996
8997   /* A restrict-qualified pointer type must be a pointer to object or
8998      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8999      REFERENCE_TYPEs, which is appropriate for C++.  */
9000   if ((type_quals & TYPE_QUAL_RESTRICT)
9001       && (!POINTER_TYPE_P (type)
9002           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
9003     {
9004       error ("invalid use of %<restrict%>");
9005       type_quals &= ~TYPE_QUAL_RESTRICT;
9006     }
9007
9008   return build_qualified_type (type, type_quals);
9009 }