gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static bool null_pointer_constant_p (const_tree);
  78 static tree qualify_type (tree, tree);
  79 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  80 static int comp_target_types (tree, tree);
  81 static int function_types_compatible_p (const_tree, const_tree);
  82 static int type_lists_compatible_p (const_tree, const_tree);
  83 static tree decl_constant_value_for_broken_optimization (tree);
  84 static tree lookup_field (tree, tree);
  85 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  86 static tree pointer_diff (tree, tree);
  87 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  88                                     int);
  89 static tree valid_compound_expr_initializer (tree, tree);
  90 static void push_string (const char *);
  91 static void push_member_name (tree);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (int, const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (const_tree, enum lvalue_use);
 106 static int lvalue_p (const_tree);
 107 static void record_maybe_used_decl (tree);
 108 static int comptypes_internal (const_tree, const_tree);
 109 \f
 110 /* Return true if EXP is a null pointer constant, false otherwise.  */
 111
 112 static bool
 113 null_pointer_constant_p (const_tree expr)
 114 {
 115   /* This should really operate on c_expr structures, but they aren't
 116      yet available everywhere required.  */
 117   tree type = TREE_TYPE (expr);
 118   return (TREE_CODE (expr) == INTEGER_CST
 119           && !TREE_OVERFLOW (expr)
 120           && integer_zerop (expr)
 121           && (INTEGRAL_TYPE_P (type)
 122               || (TREE_CODE (type) == POINTER_TYPE
 123                   && VOID_TYPE_P (TREE_TYPE (type))
 124                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 125 }
 126 \f/* This is a cache to hold if two types are compatible or not.  */
 127
 128 struct tagged_tu_seen_cache {
 129   const struct tagged_tu_seen_cache * next;
 130   const_tree t1;
 131   const_tree t2;
 132   /* The return value of tagged_types_tu_compatible_p if we had seen
 133      these two types already.  */
 134   int val;
 135 };
 136
 137 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 138 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 139
 140 /* Do `exp = require_complete_type (exp);' to make sure exp
 141    does not have an incomplete type.  (That includes void types.)  */
 142
 143 tree
 144 require_complete_type (tree value)
 145 {
 146   tree type = TREE_TYPE (value);
 147
 148   if (value == error_mark_node || type == error_mark_node)
 149     return error_mark_node;
 150
 151   /* First, detect a valid value with a complete type.  */
 152   if (COMPLETE_TYPE_P (type))
 153     return value;
 154
 155   c_incomplete_type_error (value, type);
 156   return error_mark_node;
 157 }
 158
 159 /* Print an error message for invalid use of an incomplete type.
 160    VALUE is the expression that was used (or 0 if that isn't known)
 161    and TYPE is the type that was invalid.  */
 162
 163 void
 164 c_incomplete_type_error (const_tree value, const_tree type)
 165 {
 166   const char *type_code_string;
 167
 168   /* Avoid duplicate error message.  */
 169   if (TREE_CODE (type) == ERROR_MARK)
 170     return;
 171
 172   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 173                      || TREE_CODE (value) == PARM_DECL))
 174     error ("%qD has an incomplete type", value);
 175   else
 176     {
 177     retry:
 178       /* We must print an error message.  Be clever about what it says.  */
 179
 180       switch (TREE_CODE (type))
 181         {
 182         case RECORD_TYPE:
 183           type_code_string = "struct";
 184           break;
 185
 186         case UNION_TYPE:
 187           type_code_string = "union";
 188           break;
 189
 190         case ENUMERAL_TYPE:
 191           type_code_string = "enum";
 192           break;
 193
 194         case VOID_TYPE:
 195           error ("invalid use of void expression");
 196           return;
 197
 198         case ARRAY_TYPE:
 199           if (TYPE_DOMAIN (type))
 200             {
 201               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 202                 {
 203                   error ("invalid use of flexible array member");
 204                   return;
 205                 }
 206               type = TREE_TYPE (type);
 207               goto retry;
 208             }
 209           error ("invalid use of array with unspecified bounds");
 210           return;
 211
 212         default:
 213           gcc_unreachable ();
 214         }
 215
 216       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 217         error ("invalid use of undefined type %<%s %E%>",
 218                type_code_string, TYPE_NAME (type));
 219       else
 220         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 221         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 222     }
 223 }
 224
 225 /* Given a type, apply default promotions wrt unnamed function
 226    arguments and return the new type.  */
 227
 228 tree
 229 c_type_promotes_to (tree type)
 230 {
 231   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 232     return double_type_node;
 233
 234   if (c_promoting_integer_type_p (type))
 235     {
 236       /* Preserve unsignedness if not really getting any wider.  */
 237       if (TYPE_UNSIGNED (type)
 238           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 239         return unsigned_type_node;
 240       return integer_type_node;
 241     }
 242
 243   return type;
 244 }
 245
 246 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 247    as well as those of TYPE.  */
 248
 249 static tree
 250 qualify_type (tree type, tree like)
 251 {
 252   return c_build_qualified_type (type,
 253                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 254 }
 255
 256 /* Return true iff the given tree T is a variable length array.  */
 257
 258 bool
 259 c_vla_type_p (const_tree t)
 260 {
 261   if (TREE_CODE (t) == ARRAY_TYPE
 262       && C_TYPE_VARIABLE_SIZE (t))
 263     return true;
 264   return false;
 265 }
 266 \f
 267 /* Return the composite type of two compatible types.
 268
 269    We assume that comptypes has already been done and returned
 270    nonzero; if that isn't so, this may crash.  In particular, we
 271    assume that qualifiers match.  */
 272
 273 tree
 274 composite_type (tree t1, tree t2)
 275 {
 276   enum tree_code code1;
 277   enum tree_code code2;
 278   tree attributes;
 279
 280   /* Save time if the two types are the same.  */
 281
 282   if (t1 == t2) return t1;
 283
 284   /* If one type is nonsense, use the other.  */
 285   if (t1 == error_mark_node)
 286     return t2;
 287   if (t2 == error_mark_node)
 288     return t1;
 289
 290   code1 = TREE_CODE (t1);
 291   code2 = TREE_CODE (t2);
 292
 293   /* Merge the attributes.  */
 294   attributes = targetm.merge_type_attributes (t1, t2);
 295
 296   /* If one is an enumerated type and the other is the compatible
 297      integer type, the composite type might be either of the two
 298      (DR#013 question 3).  For consistency, use the enumerated type as
 299      the composite type.  */
 300
 301   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 302     return t1;
 303   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 304     return t2;
 305
 306   gcc_assert (code1 == code2);
 307
 308   switch (code1)
 309     {
 310     case POINTER_TYPE:
 311       /* For two pointers, do this recursively on the target type.  */
 312       {
 313         tree pointed_to_1 = TREE_TYPE (t1);
 314         tree pointed_to_2 = TREE_TYPE (t2);
 315         tree target = composite_type (pointed_to_1, pointed_to_2);
 316         t1 = build_pointer_type (target);
 317         t1 = build_type_attribute_variant (t1, attributes);
 318         return qualify_type (t1, t2);
 319       }
 320
 321     case ARRAY_TYPE:
 322       {
 323         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 324         int quals;
 325         tree unqual_elt;
 326         tree d1 = TYPE_DOMAIN (t1);
 327         tree d2 = TYPE_DOMAIN (t2);
 328         bool d1_variable, d2_variable;
 329         bool d1_zero, d2_zero;
 330
 331         /* We should not have any type quals on arrays at all.  */
 332         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 333
 334         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 335         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 336
 337         d1_variable = (!d1_zero
 338                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 339                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 340         d2_variable = (!d2_zero
 341                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 342                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 343         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 344         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 345
 346         /* Save space: see if the result is identical to one of the args.  */
 347         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 348             && (d2_variable || d2_zero || !d1_variable))
 349           return build_type_attribute_variant (t1, attributes);
 350         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 351             && (d1_variable || d1_zero || !d2_variable))
 352           return build_type_attribute_variant (t2, attributes);
 353
 354         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 355           return build_type_attribute_variant (t1, attributes);
 356         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 357           return build_type_attribute_variant (t2, attributes);
 358
 359         /* Merge the element types, and have a size if either arg has
 360            one.  We may have qualifiers on the element types.  To set
 361            up TYPE_MAIN_VARIANT correctly, we need to form the
 362            composite of the unqualified types and add the qualifiers
 363            back at the end.  */
 364         quals = TYPE_QUALS (strip_array_types (elt));
 365         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 366         t1 = build_array_type (unqual_elt,
 367                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 368                                              && (d2_variable
 369                                                  || d2_zero
 370                                                  || !d1_variable))
 371                                             ? t1
 372                                             : t2));
 373         t1 = c_build_qualified_type (t1, quals);
 374         return build_type_attribute_variant (t1, attributes);
 375       }
 376
 377     case ENUMERAL_TYPE:
 378     case RECORD_TYPE:
 379     case UNION_TYPE:
 380       if (attributes != NULL)
 381         {
 382           /* Try harder not to create a new aggregate type.  */
 383           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 384             return t1;
 385           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 386             return t2;
 387         }
 388       return build_type_attribute_variant (t1, attributes);
 389
 390     case FUNCTION_TYPE:
 391       /* Function types: prefer the one that specified arg types.
 392          If both do, merge the arg types.  Also merge the return types.  */
 393       {
 394         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 395         tree p1 = TYPE_ARG_TYPES (t1);
 396         tree p2 = TYPE_ARG_TYPES (t2);
 397         int len;
 398         tree newargs, n;
 399         int i;
 400
 401         /* Save space: see if the result is identical to one of the args.  */
 402         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 403           return build_type_attribute_variant (t1, attributes);
 404         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 405           return build_type_attribute_variant (t2, attributes);
 406
 407         /* Simple way if one arg fails to specify argument types.  */
 408         if (TYPE_ARG_TYPES (t1) == 0)
 409          {
 410             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 411             t1 = build_type_attribute_variant (t1, attributes);
 412             return qualify_type (t1, t2);
 413          }
 414         if (TYPE_ARG_TYPES (t2) == 0)
 415          {
 416            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 417            t1 = build_type_attribute_variant (t1, attributes);
 418            return qualify_type (t1, t2);
 419          }
 420
 421         /* If both args specify argument types, we must merge the two
 422            lists, argument by argument.  */
 423         /* Tell global_bindings_p to return false so that variable_size
 424            doesn't die on VLAs in parameter types.  */
 425         c_override_global_bindings_to_false = true;
 426
 427         len = list_length (p1);
 428         newargs = 0;
 429
 430         for (i = 0; i < len; i++)
 431           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 432
 433         n = newargs;
 434
 435         for (; p1;
 436              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 437           {
 438             /* A null type means arg type is not specified.
 439                Take whatever the other function type has.  */
 440             if (TREE_VALUE (p1) == 0)
 441               {
 442                 TREE_VALUE (n) = TREE_VALUE (p2);
 443                 goto parm_done;
 444               }
 445             if (TREE_VALUE (p2) == 0)
 446               {
 447                 TREE_VALUE (n) = TREE_VALUE (p1);
 448                 goto parm_done;
 449               }
 450
 451             /* Given  wait (union {union wait *u; int *i} *)
 452                and  wait (union wait *),
 453                prefer  union wait *  as type of parm.  */
 454             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 455                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 456               {
 457                 tree memb;
 458                 tree mv2 = TREE_VALUE (p2);
 459                 if (mv2 && mv2 != error_mark_node
 460                     && TREE_CODE (mv2) != ARRAY_TYPE)
 461                   mv2 = TYPE_MAIN_VARIANT (mv2);
 462                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 463                      memb; memb = TREE_CHAIN (memb))
 464                   {
 465                     tree mv3 = TREE_TYPE (memb);
 466                     if (mv3 && mv3 != error_mark_node
 467                         && TREE_CODE (mv3) != ARRAY_TYPE)
 468                       mv3 = TYPE_MAIN_VARIANT (mv3);
 469                     if (comptypes (mv3, mv2))
 470                       {
 471                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 472                                                          TREE_VALUE (p2));
 473                         if (pedantic)
 474                           pedwarn ("function types not truly compatible in ISO C");
 475                         goto parm_done;
 476                       }
 477                   }
 478               }
 479             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 480                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 481               {
 482                 tree memb;
 483                 tree mv1 = TREE_VALUE (p1);
 484                 if (mv1 && mv1 != error_mark_node
 485                     && TREE_CODE (mv1) != ARRAY_TYPE)
 486                   mv1 = TYPE_MAIN_VARIANT (mv1);
 487                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 488                      memb; memb = TREE_CHAIN (memb))
 489                   {
 490                     tree mv3 = TREE_TYPE (memb);
 491                     if (mv3 && mv3 != error_mark_node
 492                         && TREE_CODE (mv3) != ARRAY_TYPE)
 493                       mv3 = TYPE_MAIN_VARIANT (mv3);
 494                     if (comptypes (mv3, mv1))
 495                       {
 496                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 497                                                          TREE_VALUE (p1));
 498                         if (pedantic)
 499                           pedwarn ("function types not truly compatible in ISO C");
 500                         goto parm_done;
 501                       }
 502                   }
 503               }
 504             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 505           parm_done: ;
 506           }
 507
 508         c_override_global_bindings_to_false = false;
 509         t1 = build_function_type (valtype, newargs);
 510         t1 = qualify_type (t1, t2);
 511         /* ... falls through ...  */
 512       }
 513
 514     default:
 515       return build_type_attribute_variant (t1, attributes);
 516     }
 517
 518 }
 519
 520 /* Return the type of a conditional expression between pointers to
 521    possibly differently qualified versions of compatible types.
 522
 523    We assume that comp_target_types has already been done and returned
 524    nonzero; if that isn't so, this may crash.  */
 525
 526 static tree
 527 common_pointer_type (tree t1, tree t2)
 528 {
 529   tree attributes;
 530   tree pointed_to_1, mv1;
 531   tree pointed_to_2, mv2;
 532   tree target;
 533   unsigned target_quals;
 534
 535   /* Save time if the two types are the same.  */
 536
 537   if (t1 == t2) return t1;
 538
 539   /* If one type is nonsense, use the other.  */
 540   if (t1 == error_mark_node)
 541     return t2;
 542   if (t2 == error_mark_node)
 543     return t1;
 544
 545   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 546               && TREE_CODE (t2) == POINTER_TYPE);
 547
 548   /* Merge the attributes.  */
 549   attributes = targetm.merge_type_attributes (t1, t2);
 550
 551   /* Find the composite type of the target types, and combine the
 552      qualifiers of the two types' targets.  Do not lose qualifiers on
 553      array element types by taking the TYPE_MAIN_VARIANT.  */
 554   mv1 = pointed_to_1 = TREE_TYPE (t1);
 555   mv2 = pointed_to_2 = TREE_TYPE (t2);
 556   if (TREE_CODE (mv1) != ARRAY_TYPE)
 557     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 558   if (TREE_CODE (mv2) != ARRAY_TYPE)
 559     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 560   target = composite_type (mv1, mv2);
 561
 562   /* For function types do not merge const qualifiers, but drop them
 563      if used inconsistently.  The middle-end uses these to mark const
 564      and noreturn functions.  */
 565   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 566     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 567   else
 568     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 569   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 570   return build_type_attribute_variant (t1, attributes);
 571 }
 572
 573 /* Return the common type for two arithmetic types under the usual
 574    arithmetic conversions.  The default conversions have already been
 575    applied, and enumerated types converted to their compatible integer
 576    types.  The resulting type is unqualified and has no attributes.
 577
 578    This is the type for the result of most arithmetic operations
 579    if the operands have the given two types.  */
 580
 581 static tree
 582 c_common_type (tree t1, tree t2)
 583 {
 584   enum tree_code code1;
 585   enum tree_code code2;
 586
 587   /* If one type is nonsense, use the other.  */
 588   if (t1 == error_mark_node)
 589     return t2;
 590   if (t2 == error_mark_node)
 591     return t1;
 592
 593   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 594     t1 = TYPE_MAIN_VARIANT (t1);
 595
 596   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 597     t2 = TYPE_MAIN_VARIANT (t2);
 598
 599   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 600     t1 = build_type_attribute_variant (t1, NULL_TREE);
 601
 602   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 603     t2 = build_type_attribute_variant (t2, NULL_TREE);
 604
 605   /* Save time if the two types are the same.  */
 606
 607   if (t1 == t2) return t1;
 608
 609   code1 = TREE_CODE (t1);
 610   code2 = TREE_CODE (t2);
 611
 612   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 613               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 614               || code1 == INTEGER_TYPE);
 615   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 616               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 617               || code2 == INTEGER_TYPE);
 618
 619   /* When one operand is a decimal float type, the other operand cannot be
 620      a generic float type or a complex type.  We also disallow vector types
 621      here.  */
 622   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 623       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 624     {
 625       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 626         {
 627           error ("can%'t mix operands of decimal float and vector types");
 628           return error_mark_node;
 629         }
 630       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 631         {
 632           error ("can%'t mix operands of decimal float and complex types");
 633           return error_mark_node;
 634         }
 635       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 636         {
 637           error ("can%'t mix operands of decimal float and other float types");
 638           return error_mark_node;
 639         }
 640     }
 641
 642   /* If one type is a vector type, return that type.  (How the usual
 643      arithmetic conversions apply to the vector types extension is not
 644      precisely specified.)  */
 645   if (code1 == VECTOR_TYPE)
 646     return t1;
 647
 648   if (code2 == VECTOR_TYPE)
 649     return t2;
 650
 651   /* If one type is complex, form the common type of the non-complex
 652      components, then make that complex.  Use T1 or T2 if it is the
 653      required type.  */
 654   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 655     {
 656       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 657       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 658       tree subtype = c_common_type (subtype1, subtype2);
 659
 660       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 661         return t1;
 662       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 663         return t2;
 664       else
 665         return build_complex_type (subtype);
 666     }
 667
 668   /* If only one is real, use it as the result.  */
 669
 670   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 671     return t1;
 672
 673   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 674     return t2;
 675
 676   /* If both are real and either are decimal floating point types, use
 677      the decimal floating point type with the greater precision. */
 678
 679   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 680     {
 681       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 682           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 683         return dfloat128_type_node;
 684       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 685                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 686         return dfloat64_type_node;
 687       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 688                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 689         return dfloat32_type_node;
 690     }
 691
 692   /* Deal with fixed-point types.  */
 693   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 694     {
 695       unsigned int unsignedp = 0, satp = 0;
 696       enum machine_mode m1, m2;
 697       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 698
 699       m1 = TYPE_MODE (t1);
 700       m2 = TYPE_MODE (t2);
 701
 702       /* If one input type is saturating, the result type is saturating.  */
 703       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 704         satp = 1;
 705
 706       /* If both fixed-point types are unsigned, the result type is unsigned.
 707          When mixing fixed-point and integer types, follow the sign of the
 708          fixed-point type.
 709          Otherwise, the result type is signed.  */
 710       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 711            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 712           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 713               && TYPE_UNSIGNED (t1))
 714           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 715               && TYPE_UNSIGNED (t2)))
 716         unsignedp = 1;
 717
 718       /* The result type is signed.  */
 719       if (unsignedp == 0)
 720         {
 721           /* If the input type is unsigned, we need to convert to the
 722              signed type.  */
 723           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 724             {
 725               unsigned char mclass = 0;
 726               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 727                 mclass = MODE_FRACT;
 728               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 729                 mclass = MODE_ACCUM;
 730               else
 731                 gcc_unreachable ();
 732               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 733             }
 734           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 735             {
 736               unsigned char mclass = 0;
 737               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 738                 mclass = MODE_FRACT;
 739               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 740                 mclass = MODE_ACCUM;
 741               else
 742                 gcc_unreachable ();
 743               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 744             }
 745         }
 746
 747       if (code1 == FIXED_POINT_TYPE)
 748         {
 749           fbit1 = GET_MODE_FBIT (m1);
 750           ibit1 = GET_MODE_IBIT (m1);
 751         }
 752       else
 753         {
 754           fbit1 = 0;
 755           /* Signed integers need to subtract one sign bit.  */
 756           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 757         }
 758
 759       if (code2 == FIXED_POINT_TYPE)
 760         {
 761           fbit2 = GET_MODE_FBIT (m2);
 762           ibit2 = GET_MODE_IBIT (m2);
 763         }
 764       else
 765         {
 766           fbit2 = 0;
 767           /* Signed integers need to subtract one sign bit.  */
 768           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 769         }
 770
 771       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 772       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 773       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 774                                                  satp);
 775     }
 776
 777   /* Both real or both integers; use the one with greater precision.  */
 778
 779   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 780     return t1;
 781   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 782     return t2;
 783
 784   /* Same precision.  Prefer long longs to longs to ints when the
 785      same precision, following the C99 rules on integer type rank
 786      (which are equivalent to the C90 rules for C90 types).  */
 787
 788   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 789       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 790     return long_long_unsigned_type_node;
 791
 792   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 793       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 794     {
 795       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 796         return long_long_unsigned_type_node;
 797       else
 798         return long_long_integer_type_node;
 799     }
 800
 801   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 802       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 803     return long_unsigned_type_node;
 804
 805   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 806       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 807     {
 808       /* But preserve unsignedness from the other type,
 809          since long cannot hold all the values of an unsigned int.  */
 810       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 811         return long_unsigned_type_node;
 812       else
 813         return long_integer_type_node;
 814     }
 815
 816   /* Likewise, prefer long double to double even if same size.  */
 817   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 818       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 819     return long_double_type_node;
 820
 821   /* Otherwise prefer the unsigned one.  */
 822
 823   if (TYPE_UNSIGNED (t1))
 824     return t1;
 825   else
 826     return t2;
 827 }
 828 \f
 829 /* Wrapper around c_common_type that is used by c-common.c and other
 830    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 831    are allowed here and are converted to their compatible integer types.
 832    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 833    preferably a non-Boolean type as the common type.  */
 834 tree
 835 common_type (tree t1, tree t2)
 836 {
 837   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 838     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 839   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 840     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 841
 842   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 843   if (TREE_CODE (t1) == BOOLEAN_TYPE
 844       && TREE_CODE (t2) == BOOLEAN_TYPE)
 845     return boolean_type_node;
 846
 847   /* If either type is BOOLEAN_TYPE, then return the other.  */
 848   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 849     return t2;
 850   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 851     return t1;
 852
 853   return c_common_type (t1, t2);
 854 }
 855
 856 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 857    or various other operations.  Return 2 if they are compatible
 858    but a warning may be needed if you use them together.  */
 859
 860 int
 861 comptypes (tree type1, tree type2)
 862 {
 863   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 864   int val;
 865
 866   val = comptypes_internal (type1, type2);
 867   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 868
 869   return val;
 870 }
 871 \f
 872 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 873    or various other operations.  Return 2 if they are compatible
 874    but a warning may be needed if you use them together.  This
 875    differs from comptypes, in that we don't free the seen types.  */
 876
 877 static int
 878 comptypes_internal (const_tree type1, const_tree type2)
 879 {
 880   const_tree t1 = type1;
 881   const_tree t2 = type2;
 882   int attrval, val;
 883
 884   /* Suppress errors caused by previously reported errors.  */
 885
 886   if (t1 == t2 || !t1 || !t2
 887       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 888     return 1;
 889
 890   /* If either type is the internal version of sizetype, return the
 891      language version.  */
 892   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 893       && TYPE_ORIG_SIZE_TYPE (t1))
 894     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 895
 896   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 897       && TYPE_ORIG_SIZE_TYPE (t2))
 898     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 899
 900
 901   /* Enumerated types are compatible with integer types, but this is
 902      not transitive: two enumerated types in the same translation unit
 903      are compatible with each other only if they are the same type.  */
 904
 905   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 906     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 907   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 908     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 909
 910   if (t1 == t2)
 911     return 1;
 912
 913   /* Different classes of types can't be compatible.  */
 914
 915   if (TREE_CODE (t1) != TREE_CODE (t2))
 916     return 0;
 917
 918   /* Qualifiers must match. C99 6.7.3p9 */
 919
 920   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 921     return 0;
 922
 923   /* Allow for two different type nodes which have essentially the same
 924      definition.  Note that we already checked for equality of the type
 925      qualifiers (just above).  */
 926
 927   if (TREE_CODE (t1) != ARRAY_TYPE
 928       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 929     return 1;
 930
 931   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 932   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 933      return 0;
 934
 935   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 936   val = 0;
 937
 938   switch (TREE_CODE (t1))
 939     {
 940     case POINTER_TYPE:
 941       /* Do not remove mode or aliasing information.  */
 942       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 943           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 944         break;
 945       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 946              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 947       break;
 948
 949     case FUNCTION_TYPE:
 950       val = function_types_compatible_p (t1, t2);
 951       break;
 952
 953     case ARRAY_TYPE:
 954       {
 955         tree d1 = TYPE_DOMAIN (t1);
 956         tree d2 = TYPE_DOMAIN (t2);
 957         bool d1_variable, d2_variable;
 958         bool d1_zero, d2_zero;
 959         val = 1;
 960
 961         /* Target types must match incl. qualifiers.  */
 962         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 963             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 964           return 0;
 965
 966         /* Sizes must match unless one is missing or variable.  */
 967         if (d1 == 0 || d2 == 0 || d1 == d2)
 968           break;
 969
 970         d1_zero = !TYPE_MAX_VALUE (d1);
 971         d2_zero = !TYPE_MAX_VALUE (d2);
 972
 973         d1_variable = (!d1_zero
 974                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 975                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 976         d2_variable = (!d2_zero
 977                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 978                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 979         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 980         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 981
 982         if (d1_variable || d2_variable)
 983           break;
 984         if (d1_zero && d2_zero)
 985           break;
 986         if (d1_zero || d2_zero
 987             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 988             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 989           val = 0;
 990
 991         break;
 992       }
 993
 994     case ENUMERAL_TYPE:
 995     case RECORD_TYPE:
 996     case UNION_TYPE:
 997       if (val != 1 && !same_translation_unit_p (t1, t2))
 998         {
 999           tree a1 = TYPE_ATTRIBUTES (t1);
1000           tree a2 = TYPE_ATTRIBUTES (t2);
1001
1002           if (! attribute_list_contained (a1, a2)
1003               && ! attribute_list_contained (a2, a1))
1004             break;
1005
1006           if (attrval != 2)
1007             return tagged_types_tu_compatible_p (t1, t2);
1008           val = tagged_types_tu_compatible_p (t1, t2);
1009         }
1010       break;
1011
1012     case VECTOR_TYPE:
1013       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1014             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1015       break;
1016
1017     default:
1018       break;
1019     }
1020   return attrval == 2 && val == 1 ? 2 : val;
1021 }
1022
1023 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1024    ignoring their qualifiers.  */
1025
1026 static int
1027 comp_target_types (tree ttl, tree ttr)
1028 {
1029   int val;
1030   tree mvl, mvr;
1031
1032   /* Do not lose qualifiers on element types of array types that are
1033      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1034   mvl = TREE_TYPE (ttl);
1035   mvr = TREE_TYPE (ttr);
1036   if (TREE_CODE (mvl) != ARRAY_TYPE)
1037     mvl = TYPE_MAIN_VARIANT (mvl);
1038   if (TREE_CODE (mvr) != ARRAY_TYPE)
1039     mvr = TYPE_MAIN_VARIANT (mvr);
1040   val = comptypes (mvl, mvr);
1041
1042   if (val == 2 && pedantic)
1043     pedwarn ("types are not quite compatible");
1044   return val;
1045 }
1046 \f
1047 /* Subroutines of `comptypes'.  */
1048
1049 /* Determine whether two trees derive from the same translation unit.
1050    If the CONTEXT chain ends in a null, that tree's context is still
1051    being parsed, so if two trees have context chains ending in null,
1052    they're in the same translation unit.  */
1053 int
1054 same_translation_unit_p (const_tree t1, const_tree t2)
1055 {
1056   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1057     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1058       {
1059       case tcc_declaration:
1060         t1 = DECL_CONTEXT (t1); break;
1061       case tcc_type:
1062         t1 = TYPE_CONTEXT (t1); break;
1063       case tcc_exceptional:
1064         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1065       default: gcc_unreachable ();
1066       }
1067
1068   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1069     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1070       {
1071       case tcc_declaration:
1072         t2 = DECL_CONTEXT (t2); break;
1073       case tcc_type:
1074         t2 = TYPE_CONTEXT (t2); break;
1075       case tcc_exceptional:
1076         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1077       default: gcc_unreachable ();
1078       }
1079
1080   return t1 == t2;
1081 }
1082
1083 /* Allocate the seen two types, assuming that they are compatible. */
1084
1085 static struct tagged_tu_seen_cache *
1086 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1087 {
1088   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1089   tu->next = tagged_tu_seen_base;
1090   tu->t1 = t1;
1091   tu->t2 = t2;
1092
1093   tagged_tu_seen_base = tu;
1094
1095   /* The C standard says that two structures in different translation
1096      units are compatible with each other only if the types of their
1097      fields are compatible (among other things).  We assume that they
1098      are compatible until proven otherwise when building the cache.
1099      An example where this can occur is:
1100      struct a
1101      {
1102        struct a *next;
1103      };
1104      If we are comparing this against a similar struct in another TU,
1105      and did not assume they were compatible, we end up with an infinite
1106      loop.  */
1107   tu->val = 1;
1108   return tu;
1109 }
1110
1111 /* Free the seen types until we get to TU_TIL. */
1112
1113 static void
1114 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1115 {
1116   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1117   while (tu != tu_til)
1118     {
1119       const struct tagged_tu_seen_cache *const tu1
1120         = (const struct tagged_tu_seen_cache *) tu;
1121       tu = tu1->next;
1122       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1123     }
1124   tagged_tu_seen_base = tu_til;
1125 }
1126
1127 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1128    compatible.  If the two types are not the same (which has been
1129    checked earlier), this can only happen when multiple translation
1130    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1131    rules.  */
1132
1133 static int
1134 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1135 {
1136   tree s1, s2;
1137   bool needs_warning = false;
1138
1139   /* We have to verify that the tags of the types are the same.  This
1140      is harder than it looks because this may be a typedef, so we have
1141      to go look at the original type.  It may even be a typedef of a
1142      typedef...
1143      In the case of compiler-created builtin structs the TYPE_DECL
1144      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1145   while (TYPE_NAME (t1)
1146          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1147          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1148     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1149
1150   while (TYPE_NAME (t2)
1151          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1152          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1153     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1154
1155   /* C90 didn't have the requirement that the two tags be the same.  */
1156   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1157     return 0;
1158
1159   /* C90 didn't say what happened if one or both of the types were
1160      incomplete; we choose to follow C99 rules here, which is that they
1161      are compatible.  */
1162   if (TYPE_SIZE (t1) == NULL
1163       || TYPE_SIZE (t2) == NULL)
1164     return 1;
1165
1166   {
1167     const struct tagged_tu_seen_cache * tts_i;
1168     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1169       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1170         return tts_i->val;
1171   }
1172
1173   switch (TREE_CODE (t1))
1174     {
1175     case ENUMERAL_TYPE:
1176       {
1177         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1178         /* Speed up the case where the type values are in the same order.  */
1179         tree tv1 = TYPE_VALUES (t1);
1180         tree tv2 = TYPE_VALUES (t2);
1181
1182         if (tv1 == tv2)
1183           {
1184             return 1;
1185           }
1186
1187         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1188           {
1189             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1190               break;
1191             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1192               {
1193                 tu->val = 0;
1194                 return 0;
1195               }
1196           }
1197
1198         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1199           {
1200             return 1;
1201           }
1202         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1203           {
1204             tu->val = 0;
1205             return 0;
1206           }
1207
1208         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1209           {
1210             tu->val = 0;
1211             return 0;
1212           }
1213
1214         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1215           {
1216             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1217             if (s2 == NULL
1218                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1219               {
1220                 tu->val = 0;
1221                 return 0;
1222               }
1223           }
1224         return 1;
1225       }
1226
1227     case UNION_TYPE:
1228       {
1229         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1230         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1231           {
1232             tu->val = 0;
1233             return 0;
1234           }
1235
1236         /*  Speed up the common case where the fields are in the same order. */
1237         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1238              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1239           {
1240             int result;
1241
1242             if (DECL_NAME (s1) != DECL_NAME (s2))
1243               break;
1244             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1245
1246             if (result != 1 && !DECL_NAME (s1))
1247               break;
1248             if (result == 0)
1249               {
1250                 tu->val = 0;
1251                 return 0;
1252               }
1253             if (result == 2)
1254               needs_warning = true;
1255
1256             if (TREE_CODE (s1) == FIELD_DECL
1257                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1258                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1259               {
1260                 tu->val = 0;
1261                 return 0;
1262               }
1263           }
1264         if (!s1 && !s2)
1265           {
1266             tu->val = needs_warning ? 2 : 1;
1267             return tu->val;
1268           }
1269
1270         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1271           {
1272             bool ok = false;
1273
1274             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1275               if (DECL_NAME (s1) == DECL_NAME (s2))
1276                 {
1277                   int result;
1278
1279                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1280
1281                   if (result != 1 && !DECL_NAME (s1))
1282                     continue;
1283                   if (result == 0)
1284                     {
1285                       tu->val = 0;
1286                       return 0;
1287                     }
1288                   if (result == 2)
1289                     needs_warning = true;
1290
1291                   if (TREE_CODE (s1) == FIELD_DECL
1292                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1293                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1294                     break;
1295
1296                   ok = true;
1297                   break;
1298                 }
1299             if (!ok)
1300               {
1301                 tu->val = 0;
1302                 return 0;
1303               }
1304           }
1305         tu->val = needs_warning ? 2 : 10;
1306         return tu->val;
1307       }
1308
1309     case RECORD_TYPE:
1310       {
1311         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1312
1313         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1314              s1 && s2;
1315              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1316           {
1317             int result;
1318             if (TREE_CODE (s1) != TREE_CODE (s2)
1319                 || DECL_NAME (s1) != DECL_NAME (s2))
1320               break;
1321             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1322             if (result == 0)
1323               break;
1324             if (result == 2)
1325               needs_warning = true;
1326
1327             if (TREE_CODE (s1) == FIELD_DECL
1328                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1329                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1330               break;
1331           }
1332         if (s1 && s2)
1333           tu->val = 0;
1334         else
1335           tu->val = needs_warning ? 2 : 1;
1336         return tu->val;
1337       }
1338
1339     default:
1340       gcc_unreachable ();
1341     }
1342 }
1343
1344 /* Return 1 if two function types F1 and F2 are compatible.
1345    If either type specifies no argument types,
1346    the other must specify a fixed number of self-promoting arg types.
1347    Otherwise, if one type specifies only the number of arguments,
1348    the other must specify that number of self-promoting arg types.
1349    Otherwise, the argument types must match.  */
1350
1351 static int
1352 function_types_compatible_p (const_tree f1, const_tree f2)
1353 {
1354   tree args1, args2;
1355   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1356   int val = 1;
1357   int val1;
1358   tree ret1, ret2;
1359
1360   ret1 = TREE_TYPE (f1);
1361   ret2 = TREE_TYPE (f2);
1362
1363   /* 'volatile' qualifiers on a function's return type used to mean
1364      the function is noreturn.  */
1365   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1366     pedwarn ("function return types not compatible due to %<volatile%>");
1367   if (TYPE_VOLATILE (ret1))
1368     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1369                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1370   if (TYPE_VOLATILE (ret2))
1371     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1372                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1373   val = comptypes_internal (ret1, ret2);
1374   if (val == 0)
1375     return 0;
1376
1377   args1 = TYPE_ARG_TYPES (f1);
1378   args2 = TYPE_ARG_TYPES (f2);
1379
1380   /* An unspecified parmlist matches any specified parmlist
1381      whose argument types don't need default promotions.  */
1382
1383   if (args1 == 0)
1384     {
1385       if (!self_promoting_args_p (args2))
1386         return 0;
1387       /* If one of these types comes from a non-prototype fn definition,
1388          compare that with the other type's arglist.
1389          If they don't match, ask for a warning (but no error).  */
1390       if (TYPE_ACTUAL_ARG_TYPES (f1)
1391           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1392         val = 2;
1393       return val;
1394     }
1395   if (args2 == 0)
1396     {
1397       if (!self_promoting_args_p (args1))
1398         return 0;
1399       if (TYPE_ACTUAL_ARG_TYPES (f2)
1400           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1401         val = 2;
1402       return val;
1403     }
1404
1405   /* Both types have argument lists: compare them and propagate results.  */
1406   val1 = type_lists_compatible_p (args1, args2);
1407   return val1 != 1 ? val1 : val;
1408 }
1409
1410 /* Check two lists of types for compatibility,
1411    returning 0 for incompatible, 1 for compatible,
1412    or 2 for compatible with warning.  */
1413
1414 static int
1415 type_lists_compatible_p (const_tree args1, const_tree args2)
1416 {
1417   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1418   int val = 1;
1419   int newval = 0;
1420
1421   while (1)
1422     {
1423       tree a1, mv1, a2, mv2;
1424       if (args1 == 0 && args2 == 0)
1425         return val;
1426       /* If one list is shorter than the other,
1427          they fail to match.  */
1428       if (args1 == 0 || args2 == 0)
1429         return 0;
1430       mv1 = a1 = TREE_VALUE (args1);
1431       mv2 = a2 = TREE_VALUE (args2);
1432       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1433         mv1 = TYPE_MAIN_VARIANT (mv1);
1434       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1435         mv2 = TYPE_MAIN_VARIANT (mv2);
1436       /* A null pointer instead of a type
1437          means there is supposed to be an argument
1438          but nothing is specified about what type it has.
1439          So match anything that self-promotes.  */
1440       if (a1 == 0)
1441         {
1442           if (c_type_promotes_to (a2) != a2)
1443             return 0;
1444         }
1445       else if (a2 == 0)
1446         {
1447           if (c_type_promotes_to (a1) != a1)
1448             return 0;
1449         }
1450       /* If one of the lists has an error marker, ignore this arg.  */
1451       else if (TREE_CODE (a1) == ERROR_MARK
1452                || TREE_CODE (a2) == ERROR_MARK)
1453         ;
1454       else if (!(newval = comptypes_internal (mv1, mv2)))
1455         {
1456           /* Allow  wait (union {union wait *u; int *i} *)
1457              and  wait (union wait *)  to be compatible.  */
1458           if (TREE_CODE (a1) == UNION_TYPE
1459               && (TYPE_NAME (a1) == 0
1460                   || TYPE_TRANSPARENT_UNION (a1))
1461               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1462               && tree_int_cst_equal (TYPE_SIZE (a1),
1463                                      TYPE_SIZE (a2)))
1464             {
1465               tree memb;
1466               for (memb = TYPE_FIELDS (a1);
1467                    memb; memb = TREE_CHAIN (memb))
1468                 {
1469                   tree mv3 = TREE_TYPE (memb);
1470                   if (mv3 && mv3 != error_mark_node
1471                       && TREE_CODE (mv3) != ARRAY_TYPE)
1472                     mv3 = TYPE_MAIN_VARIANT (mv3);
1473                   if (comptypes_internal (mv3, mv2))
1474                     break;
1475                 }
1476               if (memb == 0)
1477                 return 0;
1478             }
1479           else if (TREE_CODE (a2) == UNION_TYPE
1480                    && (TYPE_NAME (a2) == 0
1481                        || TYPE_TRANSPARENT_UNION (a2))
1482                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1483                    && tree_int_cst_equal (TYPE_SIZE (a2),
1484                                           TYPE_SIZE (a1)))
1485             {
1486               tree memb;
1487               for (memb = TYPE_FIELDS (a2);
1488                    memb; memb = TREE_CHAIN (memb))
1489                 {
1490                   tree mv3 = TREE_TYPE (memb);
1491                   if (mv3 && mv3 != error_mark_node
1492                       && TREE_CODE (mv3) != ARRAY_TYPE)
1493                     mv3 = TYPE_MAIN_VARIANT (mv3);
1494                   if (comptypes_internal (mv3, mv1))
1495                     break;
1496                 }
1497               if (memb == 0)
1498                 return 0;
1499             }
1500           else
1501             return 0;
1502         }
1503
1504       /* comptypes said ok, but record if it said to warn.  */
1505       if (newval > val)
1506         val = newval;
1507
1508       args1 = TREE_CHAIN (args1);
1509       args2 = TREE_CHAIN (args2);
1510     }
1511 }
1512 \f
1513 /* Compute the size to increment a pointer by.  */
1514
1515 static tree
1516 c_size_in_bytes (const_tree type)
1517 {
1518   enum tree_code code = TREE_CODE (type);
1519
1520   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1521     return size_one_node;
1522
1523   if (!COMPLETE_OR_VOID_TYPE_P (type))
1524     {
1525       error ("arithmetic on pointer to an incomplete type");
1526       return size_one_node;
1527     }
1528
1529   /* Convert in case a char is more than one unit.  */
1530   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1531                      size_int (TYPE_PRECISION (char_type_node)
1532                                / BITS_PER_UNIT));
1533 }
1534 \f
1535 /* Return either DECL or its known constant value (if it has one).  */
1536
1537 tree
1538 decl_constant_value (tree decl)
1539 {
1540   if (/* Don't change a variable array bound or initial value to a constant
1541          in a place where a variable is invalid.  Note that DECL_INITIAL
1542          isn't valid for a PARM_DECL.  */
1543       current_function_decl != 0
1544       && TREE_CODE (decl) != PARM_DECL
1545       && !TREE_THIS_VOLATILE (decl)
1546       && TREE_READONLY (decl)
1547       && DECL_INITIAL (decl) != 0
1548       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1549       /* This is invalid if initial value is not constant.
1550          If it has either a function call, a memory reference,
1551          or a variable, then re-evaluating it could give different results.  */
1552       && TREE_CONSTANT (DECL_INITIAL (decl))
1553       /* Check for cases where this is sub-optimal, even though valid.  */
1554       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1555     return DECL_INITIAL (decl);
1556   return decl;
1557 }
1558
1559 /* Return either DECL or its known constant value (if it has one), but
1560    return DECL if pedantic or DECL has mode BLKmode.  This is for
1561    bug-compatibility with the old behavior of decl_constant_value
1562    (before GCC 3.0); every use of this function is a bug and it should
1563    be removed before GCC 3.1.  It is not appropriate to use pedantic
1564    in a way that affects optimization, and BLKmode is probably not the
1565    right test for avoiding misoptimizations either.  */
1566
1567 static tree
1568 decl_constant_value_for_broken_optimization (tree decl)
1569 {
1570   tree ret;
1571
1572   if (pedantic || DECL_MODE (decl) == BLKmode)
1573     return decl;
1574
1575   ret = decl_constant_value (decl);
1576   /* Avoid unwanted tree sharing between the initializer and current
1577      function's body where the tree can be modified e.g. by the
1578      gimplifier.  */
1579   if (ret != decl && TREE_STATIC (decl))
1580     ret = unshare_expr (ret);
1581   return ret;
1582 }
1583
1584 /* Convert the array expression EXP to a pointer.  */
1585 static tree
1586 array_to_pointer_conversion (tree exp)
1587 {
1588   tree orig_exp = exp;
1589   tree type = TREE_TYPE (exp);
1590   tree adr;
1591   tree restype = TREE_TYPE (type);
1592   tree ptrtype;
1593
1594   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1595
1596   STRIP_TYPE_NOPS (exp);
1597
1598   if (TREE_NO_WARNING (orig_exp))
1599     TREE_NO_WARNING (exp) = 1;
1600
1601   ptrtype = build_pointer_type (restype);
1602
1603   if (TREE_CODE (exp) == INDIRECT_REF)
1604     return convert (ptrtype, TREE_OPERAND (exp, 0));
1605
1606   if (TREE_CODE (exp) == VAR_DECL)
1607     {
1608       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1609          ADDR_EXPR because it's the best way of representing what
1610          happens in C when we take the address of an array and place
1611          it in a pointer to the element type.  */
1612       adr = build1 (ADDR_EXPR, ptrtype, exp);
1613       if (!c_mark_addressable (exp))
1614         return error_mark_node;
1615       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1616       return adr;
1617     }
1618
1619   /* This way is better for a COMPONENT_REF since it can
1620      simplify the offset for a component.  */
1621   adr = build_unary_op (ADDR_EXPR, exp, 1);
1622   return convert (ptrtype, adr);
1623 }
1624
1625 /* Convert the function expression EXP to a pointer.  */
1626 static tree
1627 function_to_pointer_conversion (tree exp)
1628 {
1629   tree orig_exp = exp;
1630
1631   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1632
1633   STRIP_TYPE_NOPS (exp);
1634
1635   if (TREE_NO_WARNING (orig_exp))
1636     TREE_NO_WARNING (exp) = 1;
1637
1638   return build_unary_op (ADDR_EXPR, exp, 0);
1639 }
1640
1641 /* Perform the default conversion of arrays and functions to pointers.
1642    Return the result of converting EXP.  For any other expression, just
1643    return EXP after removing NOPs.  */
1644
1645 struct c_expr
1646 default_function_array_conversion (struct c_expr exp)
1647 {
1648   tree orig_exp = exp.value;
1649   tree type = TREE_TYPE (exp.value);
1650   enum tree_code code = TREE_CODE (type);
1651
1652   switch (code)
1653     {
1654     case ARRAY_TYPE:
1655       {
1656         bool not_lvalue = false;
1657         bool lvalue_array_p;
1658
1659         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1660                 || TREE_CODE (exp.value) == NOP_EXPR
1661                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1662                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1663           {
1664             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1665               not_lvalue = true;
1666             exp.value = TREE_OPERAND (exp.value, 0);
1667           }
1668
1669         if (TREE_NO_WARNING (orig_exp))
1670           TREE_NO_WARNING (exp.value) = 1;
1671
1672         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1673         if (!flag_isoc99 && !lvalue_array_p)
1674           {
1675             /* Before C99, non-lvalue arrays do not decay to pointers.
1676                Normally, using such an array would be invalid; but it can
1677                be used correctly inside sizeof or as a statement expression.
1678                Thus, do not give an error here; an error will result later.  */
1679             return exp;
1680           }
1681
1682         exp.value = array_to_pointer_conversion (exp.value);
1683       }
1684       break;
1685     case FUNCTION_TYPE:
1686       exp.value = function_to_pointer_conversion (exp.value);
1687       break;
1688     default:
1689       STRIP_TYPE_NOPS (exp.value);
1690       if (TREE_NO_WARNING (orig_exp))
1691         TREE_NO_WARNING (exp.value) = 1;
1692       break;
1693     }
1694
1695   return exp;
1696 }
1697
1698
1699 /* EXP is an expression of integer type.  Apply the integer promotions
1700    to it and return the promoted value.  */
1701
1702 tree
1703 perform_integral_promotions (tree exp)
1704 {
1705   tree type = TREE_TYPE (exp);
1706   enum tree_code code = TREE_CODE (type);
1707
1708   gcc_assert (INTEGRAL_TYPE_P (type));
1709
1710   /* Normally convert enums to int,
1711      but convert wide enums to something wider.  */
1712   if (code == ENUMERAL_TYPE)
1713     {
1714       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1715                                           TYPE_PRECISION (integer_type_node)),
1716                                      ((TYPE_PRECISION (type)
1717                                        >= TYPE_PRECISION (integer_type_node))
1718                                       && TYPE_UNSIGNED (type)));
1719
1720       return convert (type, exp);
1721     }
1722
1723   /* ??? This should no longer be needed now bit-fields have their
1724      proper types.  */
1725   if (TREE_CODE (exp) == COMPONENT_REF
1726       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1727       /* If it's thinner than an int, promote it like a
1728          c_promoting_integer_type_p, otherwise leave it alone.  */
1729       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1730                                TYPE_PRECISION (integer_type_node)))
1731     return convert (integer_type_node, exp);
1732
1733   if (c_promoting_integer_type_p (type))
1734     {
1735       /* Preserve unsignedness if not really getting any wider.  */
1736       if (TYPE_UNSIGNED (type)
1737           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1738         return convert (unsigned_type_node, exp);
1739
1740       return convert (integer_type_node, exp);
1741     }
1742
1743   return exp;
1744 }
1745
1746
1747 /* Perform default promotions for C data used in expressions.
1748    Enumeral types or short or char are converted to int.
1749    In addition, manifest constants symbols are replaced by their values.  */
1750
1751 tree
1752 default_conversion (tree exp)
1753 {
1754   tree orig_exp;
1755   tree type = TREE_TYPE (exp);
1756   enum tree_code code = TREE_CODE (type);
1757
1758   /* Functions and arrays have been converted during parsing.  */
1759   gcc_assert (code != FUNCTION_TYPE);
1760   if (code == ARRAY_TYPE)
1761     return exp;
1762
1763   /* Constants can be used directly unless they're not loadable.  */
1764   if (TREE_CODE (exp) == CONST_DECL)
1765     exp = DECL_INITIAL (exp);
1766
1767   /* Replace a nonvolatile const static variable with its value unless
1768      it is an array, in which case we must be sure that taking the
1769      address of the array produces consistent results.  */
1770   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1771     {
1772       exp = decl_constant_value_for_broken_optimization (exp);
1773       type = TREE_TYPE (exp);
1774     }
1775
1776   /* Strip no-op conversions.  */
1777   orig_exp = exp;
1778   STRIP_TYPE_NOPS (exp);
1779
1780   if (TREE_NO_WARNING (orig_exp))
1781     TREE_NO_WARNING (exp) = 1;
1782
1783   if (code == VOID_TYPE)
1784     {
1785       error ("void value not ignored as it ought to be");
1786       return error_mark_node;
1787     }
1788
1789   exp = require_complete_type (exp);
1790   if (exp == error_mark_node)
1791     return error_mark_node;
1792
1793   if (INTEGRAL_TYPE_P (type))
1794     return perform_integral_promotions (exp);
1795
1796   return exp;
1797 }
1798 \f
1799 /* Look up COMPONENT in a structure or union DECL.
1800
1801    If the component name is not found, returns NULL_TREE.  Otherwise,
1802    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1803    stepping down the chain to the component, which is in the last
1804    TREE_VALUE of the list.  Normally the list is of length one, but if
1805    the component is embedded within (nested) anonymous structures or
1806    unions, the list steps down the chain to the component.  */
1807
1808 static tree
1809 lookup_field (tree decl, tree component)
1810 {
1811   tree type = TREE_TYPE (decl);
1812   tree field;
1813
1814   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1815      to the field elements.  Use a binary search on this array to quickly
1816      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1817      will always be set for structures which have many elements.  */
1818
1819   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1820     {
1821       int bot, top, half;
1822       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1823
1824       field = TYPE_FIELDS (type);
1825       bot = 0;
1826       top = TYPE_LANG_SPECIFIC (type)->s->len;
1827       while (top - bot > 1)
1828         {
1829           half = (top - bot + 1) >> 1;
1830           field = field_array[bot+half];
1831
1832           if (DECL_NAME (field) == NULL_TREE)
1833             {
1834               /* Step through all anon unions in linear fashion.  */
1835               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1836                 {
1837                   field = field_array[bot++];
1838                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1839                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1840                     {
1841                       tree anon = lookup_field (field, component);
1842
1843                       if (anon)
1844                         return tree_cons (NULL_TREE, field, anon);
1845                     }
1846                 }
1847
1848               /* Entire record is only anon unions.  */
1849               if (bot > top)
1850                 return NULL_TREE;
1851
1852               /* Restart the binary search, with new lower bound.  */
1853               continue;
1854             }
1855
1856           if (DECL_NAME (field) == component)
1857             break;
1858           if (DECL_NAME (field) < component)
1859             bot += half;
1860           else
1861             top = bot + half;
1862         }
1863
1864       if (DECL_NAME (field_array[bot]) == component)
1865         field = field_array[bot];
1866       else if (DECL_NAME (field) != component)
1867         return NULL_TREE;
1868     }
1869   else
1870     {
1871       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1872         {
1873           if (DECL_NAME (field) == NULL_TREE
1874               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1875                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1876             {
1877               tree anon = lookup_field (field, component);
1878
1879               if (anon)
1880                 return tree_cons (NULL_TREE, field, anon);
1881             }
1882
1883           if (DECL_NAME (field) == component)
1884             break;
1885         }
1886
1887       if (field == NULL_TREE)
1888         return NULL_TREE;
1889     }
1890
1891   return tree_cons (NULL_TREE, field, NULL_TREE);
1892 }
1893
1894 /* Make an expression to refer to the COMPONENT field of
1895    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1896
1897 tree
1898 build_component_ref (tree datum, tree component)
1899 {
1900   tree type = TREE_TYPE (datum);
1901   enum tree_code code = TREE_CODE (type);
1902   tree field = NULL;
1903   tree ref;
1904
1905   if (!objc_is_public (datum, component))
1906     return error_mark_node;
1907
1908   /* See if there is a field or component with name COMPONENT.  */
1909
1910   if (code == RECORD_TYPE || code == UNION_TYPE)
1911     {
1912       if (!COMPLETE_TYPE_P (type))
1913         {
1914           c_incomplete_type_error (NULL_TREE, type);
1915           return error_mark_node;
1916         }
1917
1918       field = lookup_field (datum, component);
1919
1920       if (!field)
1921         {
1922           error ("%qT has no member named %qE", type, component);
1923           return error_mark_node;
1924         }
1925
1926       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1927          This might be better solved in future the way the C++ front
1928          end does it - by giving the anonymous entities each a
1929          separate name and type, and then have build_component_ref
1930          recursively call itself.  We can't do that here.  */
1931       do
1932         {
1933           tree subdatum = TREE_VALUE (field);
1934           int quals;
1935           tree subtype;
1936
1937           if (TREE_TYPE (subdatum) == error_mark_node)
1938             return error_mark_node;
1939
1940           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1941           quals |= TYPE_QUALS (TREE_TYPE (datum));
1942           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1943
1944           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1945                         NULL_TREE);
1946           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1947             TREE_READONLY (ref) = 1;
1948           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1949             TREE_THIS_VOLATILE (ref) = 1;
1950
1951           if (TREE_DEPRECATED (subdatum))
1952             warn_deprecated_use (subdatum);
1953
1954           datum = ref;
1955
1956           field = TREE_CHAIN (field);
1957         }
1958       while (field);
1959
1960       return ref;
1961     }
1962   else if (code != ERROR_MARK)
1963     error ("request for member %qE in something not a structure or union",
1964            component);
1965
1966   return error_mark_node;
1967 }
1968 \f
1969 /* Given an expression PTR for a pointer, return an expression
1970    for the value pointed to.
1971    ERRORSTRING is the name of the operator to appear in error messages.  */
1972
1973 tree
1974 build_indirect_ref (tree ptr, const char *errorstring)
1975 {
1976   tree pointer = default_conversion (ptr);
1977   tree type = TREE_TYPE (pointer);
1978
1979   if (TREE_CODE (type) == POINTER_TYPE)
1980     {
1981       if (TREE_CODE (pointer) == CONVERT_EXPR
1982           || TREE_CODE (pointer) == NOP_EXPR
1983           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1984         {
1985           /* If a warning is issued, mark it to avoid duplicates from
1986              the backend.  This only needs to be done at
1987              warn_strict_aliasing > 2.  */
1988           if (warn_strict_aliasing > 2)
1989             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1990                                          type, TREE_OPERAND (pointer, 0)))
1991               TREE_NO_WARNING (pointer) = 1;
1992         }
1993
1994       if (TREE_CODE (pointer) == ADDR_EXPR
1995           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1996               == TREE_TYPE (type)))
1997         return TREE_OPERAND (pointer, 0);
1998       else
1999         {
2000           tree t = TREE_TYPE (type);
2001           tree ref;
2002
2003           ref = build1 (INDIRECT_REF, t, pointer);
2004
2005           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2006             {
2007               error ("dereferencing pointer to incomplete type");
2008               return error_mark_node;
2009             }
2010           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2011             warning (0, "dereferencing %<void *%> pointer");
2012
2013           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2014              so that we get the proper error message if the result is used
2015              to assign to.  Also, &* is supposed to be a no-op.
2016              And ANSI C seems to specify that the type of the result
2017              should be the const type.  */
2018           /* A de-reference of a pointer to const is not a const.  It is valid
2019              to change it via some other pointer.  */
2020           TREE_READONLY (ref) = TYPE_READONLY (t);
2021           TREE_SIDE_EFFECTS (ref)
2022             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2023           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2024           return ref;
2025         }
2026     }
2027   else if (TREE_CODE (pointer) != ERROR_MARK)
2028     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2029   return error_mark_node;
2030 }
2031
2032 /* This handles expressions of the form "a[i]", which denotes
2033    an array reference.
2034
2035    This is logically equivalent in C to *(a+i), but we may do it differently.
2036    If A is a variable or a member, we generate a primitive ARRAY_REF.
2037    This avoids forcing the array out of registers, and can work on
2038    arrays that are not lvalues (for example, members of structures returned
2039    by functions).  */
2040
2041 tree
2042 build_array_ref (tree array, tree index)
2043 {
2044   bool swapped = false;
2045   if (TREE_TYPE (array) == error_mark_node
2046       || TREE_TYPE (index) == error_mark_node)
2047     return error_mark_node;
2048
2049   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2050       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2051     {
2052       tree temp;
2053       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2054           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2055         {
2056           error ("subscripted value is neither array nor pointer");
2057           return error_mark_node;
2058         }
2059       temp = array;
2060       array = index;
2061       index = temp;
2062       swapped = true;
2063     }
2064
2065   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2066     {
2067       error ("array subscript is not an integer");
2068       return error_mark_node;
2069     }
2070
2071   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2072     {
2073       error ("subscripted value is pointer to function");
2074       return error_mark_node;
2075     }
2076
2077   /* ??? Existing practice has been to warn only when the char
2078      index is syntactically the index, not for char[array].  */
2079   if (!swapped)
2080      warn_array_subscript_with_type_char (index);
2081
2082   /* Apply default promotions *after* noticing character types.  */
2083   index = default_conversion (index);
2084
2085   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2086
2087   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2088     {
2089       tree rval, type;
2090
2091       /* An array that is indexed by a non-constant
2092          cannot be stored in a register; we must be able to do
2093          address arithmetic on its address.
2094          Likewise an array of elements of variable size.  */
2095       if (TREE_CODE (index) != INTEGER_CST
2096           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2097               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2098         {
2099           if (!c_mark_addressable (array))
2100             return error_mark_node;
2101         }
2102       /* An array that is indexed by a constant value which is not within
2103          the array bounds cannot be stored in a register either; because we
2104          would get a crash in store_bit_field/extract_bit_field when trying
2105          to access a non-existent part of the register.  */
2106       if (TREE_CODE (index) == INTEGER_CST
2107           && TYPE_DOMAIN (TREE_TYPE (array))
2108           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2109         {
2110           if (!c_mark_addressable (array))
2111             return error_mark_node;
2112         }
2113
2114       if (pedantic)
2115         {
2116           tree foo = array;
2117           while (TREE_CODE (foo) == COMPONENT_REF)
2118             foo = TREE_OPERAND (foo, 0);
2119           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2120             pedwarn ("ISO C forbids subscripting %<register%> array");
2121           else if (!flag_isoc99 && !lvalue_p (foo))
2122             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2123         }
2124
2125       type = TREE_TYPE (TREE_TYPE (array));
2126       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2127       /* Array ref is const/volatile if the array elements are
2128          or if the array is.  */
2129       TREE_READONLY (rval)
2130         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2131             | TREE_READONLY (array));
2132       TREE_SIDE_EFFECTS (rval)
2133         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2134             | TREE_SIDE_EFFECTS (array));
2135       TREE_THIS_VOLATILE (rval)
2136         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2137             /* This was added by rms on 16 Nov 91.
2138                It fixes  vol struct foo *a;  a->elts[1]
2139                in an inline function.
2140                Hope it doesn't break something else.  */
2141             | TREE_THIS_VOLATILE (array));
2142       return require_complete_type (fold (rval));
2143     }
2144   else
2145     {
2146       tree ar = default_conversion (array);
2147
2148       if (ar == error_mark_node)
2149         return ar;
2150
2151       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2152       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2153
2154       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2155                                  "array indexing");
2156     }
2157 }
2158 \f
2159 /* Build an external reference to identifier ID.  FUN indicates
2160    whether this will be used for a function call.  LOC is the source
2161    location of the identifier.  */
2162 tree
2163 build_external_ref (tree id, int fun, location_t loc)
2164 {
2165   tree ref;
2166   tree decl = lookup_name (id);
2167
2168   /* In Objective-C, an instance variable (ivar) may be preferred to
2169      whatever lookup_name() found.  */
2170   decl = objc_lookup_ivar (decl, id);
2171
2172   if (decl && decl != error_mark_node)
2173     ref = decl;
2174   else if (fun)
2175     /* Implicit function declaration.  */
2176     ref = implicitly_declare (id);
2177   else if (decl == error_mark_node)
2178     /* Don't complain about something that's already been
2179        complained about.  */
2180     return error_mark_node;
2181   else
2182     {
2183       undeclared_variable (id, loc);
2184       return error_mark_node;
2185     }
2186
2187   if (TREE_TYPE (ref) == error_mark_node)
2188     return error_mark_node;
2189
2190   if (TREE_DEPRECATED (ref))
2191     warn_deprecated_use (ref);
2192
2193   /* Recursive call does not count as usage.  */
2194   if (ref != current_function_decl)
2195     {
2196       if (!skip_evaluation)
2197         assemble_external (ref);
2198       TREE_USED (ref) = 1;
2199     }
2200
2201   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2202     {
2203       if (!in_sizeof && !in_typeof)
2204         C_DECL_USED (ref) = 1;
2205       else if (DECL_INITIAL (ref) == 0
2206                && DECL_EXTERNAL (ref)
2207                && !TREE_PUBLIC (ref))
2208         record_maybe_used_decl (ref);
2209     }
2210
2211   if (TREE_CODE (ref) == CONST_DECL)
2212     {
2213       used_types_insert (TREE_TYPE (ref));
2214       ref = DECL_INITIAL (ref);
2215       TREE_CONSTANT (ref) = 1;
2216       TREE_INVARIANT (ref) = 1;
2217     }
2218   else if (current_function_decl != 0
2219            && !DECL_FILE_SCOPE_P (current_function_decl)
2220            && (TREE_CODE (ref) == VAR_DECL
2221                || TREE_CODE (ref) == PARM_DECL
2222                || TREE_CODE (ref) == FUNCTION_DECL))
2223     {
2224       tree context = decl_function_context (ref);
2225
2226       if (context != 0 && context != current_function_decl)
2227         DECL_NONLOCAL (ref) = 1;
2228     }
2229   /* C99 6.7.4p3: An inline definition of a function with external
2230      linkage ... shall not contain a reference to an identifier with
2231      internal linkage.  */
2232   else if (current_function_decl != 0
2233            && DECL_DECLARED_INLINE_P (current_function_decl)
2234            && DECL_EXTERNAL (current_function_decl)
2235            && VAR_OR_FUNCTION_DECL_P (ref)
2236            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2237            && ! TREE_PUBLIC (ref)
2238            && DECL_CONTEXT (ref) != current_function_decl)
2239     pedwarn ("%H%qD is static but used in inline function %qD "
2240              "which is not static", &loc, ref, current_function_decl);
2241
2242   return ref;
2243 }
2244
2245 /* Record details of decls possibly used inside sizeof or typeof.  */
2246 struct maybe_used_decl
2247 {
2248   /* The decl.  */
2249   tree decl;
2250   /* The level seen at (in_sizeof + in_typeof).  */
2251   int level;
2252   /* The next one at this level or above, or NULL.  */
2253   struct maybe_used_decl *next;
2254 };
2255
2256 static struct maybe_used_decl *maybe_used_decls;
2257
2258 /* Record that DECL, an undefined static function reference seen
2259    inside sizeof or typeof, might be used if the operand of sizeof is
2260    a VLA type or the operand of typeof is a variably modified
2261    type.  */
2262
2263 static void
2264 record_maybe_used_decl (tree decl)
2265 {
2266   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2267   t->decl = decl;
2268   t->level = in_sizeof + in_typeof;
2269   t->next = maybe_used_decls;
2270   maybe_used_decls = t;
2271 }
2272
2273 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2274    USED is false, just discard them.  If it is true, mark them used
2275    (if no longer inside sizeof or typeof) or move them to the next
2276    level up (if still inside sizeof or typeof).  */
2277
2278 void
2279 pop_maybe_used (bool used)
2280 {
2281   struct maybe_used_decl *p = maybe_used_decls;
2282   int cur_level = in_sizeof + in_typeof;
2283   while (p && p->level > cur_level)
2284     {
2285       if (used)
2286         {
2287           if (cur_level == 0)
2288             C_DECL_USED (p->decl) = 1;
2289           else
2290             p->level = cur_level;
2291         }
2292       p = p->next;
2293     }
2294   if (!used || cur_level == 0)
2295     maybe_used_decls = p;
2296 }
2297
2298 /* Return the result of sizeof applied to EXPR.  */
2299
2300 struct c_expr
2301 c_expr_sizeof_expr (struct c_expr expr)
2302 {
2303   struct c_expr ret;
2304   if (expr.value == error_mark_node)
2305     {
2306       ret.value = error_mark_node;
2307       ret.original_code = ERROR_MARK;
2308       pop_maybe_used (false);
2309     }
2310   else
2311     {
2312       ret.value = c_sizeof (TREE_TYPE (expr.value));
2313       ret.original_code = ERROR_MARK;
2314       if (c_vla_type_p (TREE_TYPE (expr.value)))
2315         {
2316           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2317           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2318         }
2319       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2320     }
2321   return ret;
2322 }
2323
2324 /* Return the result of sizeof applied to T, a structure for the type
2325    name passed to sizeof (rather than the type itself).  */
2326
2327 struct c_expr
2328 c_expr_sizeof_type (struct c_type_name *t)
2329 {
2330   tree type;
2331   struct c_expr ret;
2332   type = groktypename (t);
2333   ret.value = c_sizeof (type);
2334   ret.original_code = ERROR_MARK;
2335   pop_maybe_used (type != error_mark_node
2336                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2337   return ret;
2338 }
2339
2340 /* Build a function call to function FUNCTION with parameters PARAMS.
2341    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2342    TREE_VALUE of each node is a parameter-expression.
2343    FUNCTION's data type may be a function type or a pointer-to-function.  */
2344
2345 tree
2346 build_function_call (tree function, tree params)
2347 {
2348   tree fntype, fundecl = 0;
2349   tree name = NULL_TREE, result;
2350   tree tem;
2351   int nargs;
2352   tree *argarray;
2353
2354
2355   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2356   STRIP_TYPE_NOPS (function);
2357
2358   /* Convert anything with function type to a pointer-to-function.  */
2359   if (TREE_CODE (function) == FUNCTION_DECL)
2360     {
2361       /* Implement type-directed function overloading for builtins.
2362          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2363          handle all the type checking.  The result is a complete expression
2364          that implements this function call.  */
2365       tem = resolve_overloaded_builtin (function, params);
2366       if (tem)
2367         return tem;
2368
2369       name = DECL_NAME (function);
2370       fundecl = function;
2371     }
2372   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2373     function = function_to_pointer_conversion (function);
2374
2375   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2376      expressions, like those used for ObjC messenger dispatches.  */
2377   function = objc_rewrite_function_call (function, params);
2378
2379   fntype = TREE_TYPE (function);
2380
2381   if (TREE_CODE (fntype) == ERROR_MARK)
2382     return error_mark_node;
2383
2384   if (!(TREE_CODE (fntype) == POINTER_TYPE
2385         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2386     {
2387       error ("called object %qE is not a function", function);
2388       return error_mark_node;
2389     }
2390
2391   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2392     current_function_returns_abnormally = 1;
2393
2394   /* fntype now gets the type of function pointed to.  */
2395   fntype = TREE_TYPE (fntype);
2396
2397   /* Check that the function is called through a compatible prototype.
2398      If it is not, replace the call by a trap, wrapped up in a compound
2399      expression if necessary.  This has the nice side-effect to prevent
2400      the tree-inliner from generating invalid assignment trees which may
2401      blow up in the RTL expander later.  */
2402   if ((TREE_CODE (function) == NOP_EXPR
2403        || TREE_CODE (function) == CONVERT_EXPR)
2404       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2405       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2406       && !comptypes (fntype, TREE_TYPE (tem)))
2407     {
2408       tree return_type = TREE_TYPE (fntype);
2409       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2410                                        NULL_TREE);
2411
2412       /* This situation leads to run-time undefined behavior.  We can't,
2413          therefore, simply error unless we can prove that all possible
2414          executions of the program must execute the code.  */
2415       warning (0, "function called through a non-compatible type");
2416
2417       /* We can, however, treat "undefined" any way we please.
2418          Call abort to encourage the user to fix the program.  */
2419       inform ("if this code is reached, the program will abort");
2420
2421       if (VOID_TYPE_P (return_type))
2422         return trap;
2423       else
2424         {
2425           tree rhs;
2426
2427           if (AGGREGATE_TYPE_P (return_type))
2428             rhs = build_compound_literal (return_type,
2429                                           build_constructor (return_type, 0));
2430           else
2431             rhs = fold_convert (return_type, integer_zero_node);
2432
2433           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2434         }
2435     }
2436
2437   /* Convert the parameters to the types declared in the
2438      function prototype, or apply default promotions.  */
2439
2440   nargs = list_length (params);
2441   argarray = (tree *) alloca (nargs * sizeof (tree));
2442   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2443                              params, function, fundecl);
2444   if (nargs < 0)
2445     return error_mark_node;
2446
2447   /* Check that the arguments to the function are valid.  */
2448
2449   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2450                             TYPE_ARG_TYPES (fntype));
2451
2452   if (require_constant_value)
2453     {
2454       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2455                                                   function, nargs, argarray);
2456       if (TREE_CONSTANT (result)
2457           && (name == NULL_TREE
2458               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2459         pedwarn_init ("initializer element is not constant");
2460     }
2461   else
2462     result = fold_build_call_array (TREE_TYPE (fntype),
2463                                     function, nargs, argarray);
2464
2465   if (VOID_TYPE_P (TREE_TYPE (result)))
2466     return result;
2467   return require_complete_type (result);
2468 }
2469 \f
2470 /* Convert the argument expressions in the list VALUES
2471    to the types in the list TYPELIST.  The resulting arguments are
2472    stored in the array ARGARRAY which has size NARGS.
2473
2474    If TYPELIST is exhausted, or when an element has NULL as its type,
2475    perform the default conversions.
2476
2477    PARMLIST is the chain of parm decls for the function being called.
2478    It may be 0, if that info is not available.
2479    It is used only for generating error messages.
2480
2481    FUNCTION is a tree for the called function.  It is used only for
2482    error messages, where it is formatted with %qE.
2483
2484    This is also where warnings about wrong number of args are generated.
2485
2486    VALUES is a chain of TREE_LIST nodes with the elements of the list
2487    in the TREE_VALUE slots of those nodes.
2488
2489    Returns the actual number of arguments processed (which may be less
2490    than NARGS in some error situations), or -1 on failure.  */
2491
2492 static int
2493 convert_arguments (int nargs, tree *argarray,
2494                    tree typelist, tree values, tree function, tree fundecl)
2495 {
2496   tree typetail, valtail;
2497   int parmnum;
2498   const bool type_generic = fundecl
2499     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2500   tree selector;
2501
2502   /* Change pointer to function to the function itself for
2503      diagnostics.  */
2504   if (TREE_CODE (function) == ADDR_EXPR
2505       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2506     function = TREE_OPERAND (function, 0);
2507
2508   /* Handle an ObjC selector specially for diagnostics.  */
2509   selector = objc_message_selector ();
2510
2511   /* Scan the given expressions and types, producing individual
2512      converted arguments and storing them in ARGARRAY.  */
2513
2514   for (valtail = values, typetail = typelist, parmnum = 0;
2515        valtail;
2516        valtail = TREE_CHAIN (valtail), parmnum++)
2517     {
2518       tree type = typetail ? TREE_VALUE (typetail) : 0;
2519       tree val = TREE_VALUE (valtail);
2520       tree rname = function;
2521       int argnum = parmnum + 1;
2522       const char *invalid_func_diag;
2523
2524       if (type == void_type_node)
2525         {
2526           error ("too many arguments to function %qE", function);
2527           return parmnum;
2528         }
2529
2530       if (selector && argnum > 2)
2531         {
2532           rname = selector;
2533           argnum -= 2;
2534         }
2535
2536       STRIP_TYPE_NOPS (val);
2537
2538       val = require_complete_type (val);
2539
2540       if (type != 0)
2541         {
2542           /* Formal parm type is specified by a function prototype.  */
2543           tree parmval;
2544
2545           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2546             {
2547               error ("type of formal parameter %d is incomplete", parmnum + 1);
2548               parmval = val;
2549             }
2550           else
2551             {
2552               /* Optionally warn about conversions that
2553                  differ from the default conversions.  */
2554               if (warn_traditional_conversion || warn_traditional)
2555                 {
2556                   unsigned int formal_prec = TYPE_PRECISION (type);
2557
2558                   if (INTEGRAL_TYPE_P (type)
2559                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2560                     warning (0, "passing argument %d of %qE as integer "
2561                              "rather than floating due to prototype",
2562                              argnum, rname);
2563                   if (INTEGRAL_TYPE_P (type)
2564                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2565                     warning (0, "passing argument %d of %qE as integer "
2566                              "rather than complex due to prototype",
2567                              argnum, rname);
2568                   else if (TREE_CODE (type) == COMPLEX_TYPE
2569                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2570                     warning (0, "passing argument %d of %qE as complex "
2571                              "rather than floating due to prototype",
2572                              argnum, rname);
2573                   else if (TREE_CODE (type) == REAL_TYPE
2574                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2575                     warning (0, "passing argument %d of %qE as floating "
2576                              "rather than integer due to prototype",
2577                              argnum, rname);
2578                   else if (TREE_CODE (type) == COMPLEX_TYPE
2579                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2580                     warning (0, "passing argument %d of %qE as complex "
2581                              "rather than integer due to prototype",
2582                              argnum, rname);
2583                   else if (TREE_CODE (type) == REAL_TYPE
2584                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2585                     warning (0, "passing argument %d of %qE as floating "
2586                              "rather than complex due to prototype",
2587                              argnum, rname);
2588                   /* ??? At some point, messages should be written about
2589                      conversions between complex types, but that's too messy
2590                      to do now.  */
2591                   else if (TREE_CODE (type) == REAL_TYPE
2592                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2593                     {
2594                       /* Warn if any argument is passed as `float',
2595                          since without a prototype it would be `double'.  */
2596                       if (formal_prec == TYPE_PRECISION (float_type_node)
2597                           && type != dfloat32_type_node)
2598                         warning (0, "passing argument %d of %qE as %<float%> "
2599                                  "rather than %<double%> due to prototype",
2600                                  argnum, rname);
2601
2602                       /* Warn if mismatch between argument and prototype
2603                          for decimal float types.  Warn of conversions with
2604                          binary float types and of precision narrowing due to
2605                          prototype. */
2606                       else if (type != TREE_TYPE (val)
2607                                && (type == dfloat32_type_node
2608                                    || type == dfloat64_type_node
2609                                    || type == dfloat128_type_node
2610                                    || TREE_TYPE (val) == dfloat32_type_node
2611                                    || TREE_TYPE (val) == dfloat64_type_node
2612                                    || TREE_TYPE (val) == dfloat128_type_node)
2613                                && (formal_prec
2614                                    <= TYPE_PRECISION (TREE_TYPE (val))
2615                                    || (type == dfloat128_type_node
2616                                        && (TREE_TYPE (val)
2617                                            != dfloat64_type_node
2618                                            && (TREE_TYPE (val)
2619                                                != dfloat32_type_node)))
2620                                    || (type == dfloat64_type_node
2621                                        && (TREE_TYPE (val)
2622                                            != dfloat32_type_node))))
2623                         warning (0, "passing argument %d of %qE as %qT "
2624                                  "rather than %qT due to prototype",
2625                                  argnum, rname, type, TREE_TYPE (val));
2626
2627                     }
2628                   /* Detect integer changing in width or signedness.
2629                      These warnings are only activated with
2630                      -Wtraditional-conversion, not with -Wtraditional.  */
2631                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2632                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2633                     {
2634                       tree would_have_been = default_conversion (val);
2635                       tree type1 = TREE_TYPE (would_have_been);
2636
2637                       if (TREE_CODE (type) == ENUMERAL_TYPE
2638                           && (TYPE_MAIN_VARIANT (type)
2639                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2640                         /* No warning if function asks for enum
2641                            and the actual arg is that enum type.  */
2642                         ;
2643                       else if (formal_prec != TYPE_PRECISION (type1))
2644                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2645                                  "with different width due to prototype",
2646                                  argnum, rname);
2647                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2648                         ;
2649                       /* Don't complain if the formal parameter type
2650                          is an enum, because we can't tell now whether
2651                          the value was an enum--even the same enum.  */
2652                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2653                         ;
2654                       else if (TREE_CODE (val) == INTEGER_CST
2655                                && int_fits_type_p (val, type))
2656                         /* Change in signedness doesn't matter
2657                            if a constant value is unaffected.  */
2658                         ;
2659                       /* If the value is extended from a narrower
2660                          unsigned type, it doesn't matter whether we
2661                          pass it as signed or unsigned; the value
2662                          certainly is the same either way.  */
2663                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2664                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2665                         ;
2666                       else if (TYPE_UNSIGNED (type))
2667                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2668                                  "as unsigned due to prototype",
2669                                  argnum, rname);
2670                       else
2671                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2672                                  "as signed due to prototype", argnum, rname);
2673                     }
2674                 }
2675
2676               parmval = convert_for_assignment (type, val, ic_argpass,
2677                                                 fundecl, function,
2678                                                 parmnum + 1);
2679
2680               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2681                   && INTEGRAL_TYPE_P (type)
2682                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2683                 parmval = default_conversion (parmval);
2684             }
2685           argarray[parmnum] = parmval;
2686         }
2687       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2688                && (TYPE_PRECISION (TREE_TYPE (val))
2689                    < TYPE_PRECISION (double_type_node))
2690                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2691         {
2692           if (type_generic)
2693             argarray[parmnum] = val;
2694           else
2695             /* Convert `float' to `double'.  */
2696             argarray[parmnum] = convert (double_type_node, val);
2697         }
2698       else if ((invalid_func_diag =
2699                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2700         {
2701           error (invalid_func_diag);
2702           return -1;
2703         }
2704       else
2705         /* Convert `short' and `char' to full-size `int'.  */
2706         argarray[parmnum] = default_conversion (val);
2707
2708       if (typetail)
2709         typetail = TREE_CHAIN (typetail);
2710     }
2711
2712   gcc_assert (parmnum == nargs);
2713
2714   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2715     {
2716       error ("too few arguments to function %qE", function);
2717       return -1;
2718     }
2719
2720   return parmnum;
2721 }
2722 \f
2723 /* This is the entry point used by the parser to build unary operators
2724    in the input.  CODE, a tree_code, specifies the unary operator, and
2725    ARG is the operand.  For unary plus, the C parser currently uses
2726    CONVERT_EXPR for code.  */
2727
2728 struct c_expr
2729 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2730 {
2731   struct c_expr result;
2732
2733   result.original_code = ERROR_MARK;
2734   result.value = build_unary_op (code, arg.value, 0);
2735
2736   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2737     overflow_warning (result.value);
2738
2739   return result;
2740 }
2741
2742 /* This is the entry point used by the parser to build binary operators
2743    in the input.  CODE, a tree_code, specifies the binary operator, and
2744    ARG1 and ARG2 are the operands.  In addition to constructing the
2745    expression, we check for operands that were written with other binary
2746    operators in a way that is likely to confuse the user.  */
2747
2748 struct c_expr
2749 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2750                         struct c_expr arg2)
2751 {
2752   struct c_expr result;
2753
2754   enum tree_code code1 = arg1.original_code;
2755   enum tree_code code2 = arg2.original_code;
2756
2757   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2758   result.original_code = code;
2759
2760   if (TREE_CODE (result.value) == ERROR_MARK)
2761     return result;
2762
2763   /* Check for cases such as x+y<<z which users are likely
2764      to misinterpret.  */
2765   if (warn_parentheses)
2766     warn_about_parentheses (code, code1, code2);
2767
2768   if (code1 != tcc_comparison)
2769     warn_logical_operator (code, arg1.value, arg2.value);
2770
2771   /* Warn about comparisons against string literals, with the exception
2772      of testing for equality or inequality of a string literal with NULL.  */
2773   if (code == EQ_EXPR || code == NE_EXPR)
2774     {
2775       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2776           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2777         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2778     }
2779   else if (TREE_CODE_CLASS (code) == tcc_comparison
2780            && (code1 == STRING_CST || code2 == STRING_CST))
2781     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2782
2783   if (TREE_OVERFLOW_P (result.value)
2784       && !TREE_OVERFLOW_P (arg1.value)
2785       && !TREE_OVERFLOW_P (arg2.value))
2786     overflow_warning (result.value);
2787
2788   return result;
2789 }
2790 \f
2791 /* Return a tree for the difference of pointers OP0 and OP1.
2792    The resulting tree has type int.  */
2793
2794 static tree
2795 pointer_diff (tree op0, tree op1)
2796 {
2797   tree restype = ptrdiff_type_node;
2798
2799   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2800   tree con0, con1, lit0, lit1;
2801   tree orig_op1 = op1;
2802
2803   if (pedantic || warn_pointer_arith)
2804     {
2805       if (TREE_CODE (target_type) == VOID_TYPE)
2806         pedwarn ("pointer of type %<void *%> used in subtraction");
2807       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2808         pedwarn ("pointer to a function used in subtraction");
2809     }
2810
2811   /* If the conversion to ptrdiff_type does anything like widening or
2812      converting a partial to an integral mode, we get a convert_expression
2813      that is in the way to do any simplifications.
2814      (fold-const.c doesn't know that the extra bits won't be needed.
2815      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2816      different mode in place.)
2817      So first try to find a common term here 'by hand'; we want to cover
2818      at least the cases that occur in legal static initializers.  */
2819   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2820       && (TYPE_PRECISION (TREE_TYPE (op0))
2821           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2822     con0 = TREE_OPERAND (op0, 0);
2823   else
2824     con0 = op0;
2825   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2826       && (TYPE_PRECISION (TREE_TYPE (op1))
2827           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2828     con1 = TREE_OPERAND (op1, 0);
2829   else
2830     con1 = op1;
2831
2832   if (TREE_CODE (con0) == PLUS_EXPR)
2833     {
2834       lit0 = TREE_OPERAND (con0, 1);
2835       con0 = TREE_OPERAND (con0, 0);
2836     }
2837   else
2838     lit0 = integer_zero_node;
2839
2840   if (TREE_CODE (con1) == PLUS_EXPR)
2841     {
2842       lit1 = TREE_OPERAND (con1, 1);
2843       con1 = TREE_OPERAND (con1, 0);
2844     }
2845   else
2846     lit1 = integer_zero_node;
2847
2848   if (operand_equal_p (con0, con1, 0))
2849     {
2850       op0 = lit0;
2851       op1 = lit1;
2852     }
2853
2854
2855   /* First do the subtraction as integers;
2856      then drop through to build the divide operator.
2857      Do not do default conversions on the minus operator
2858      in case restype is a short type.  */
2859
2860   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2861                          convert (restype, op1), 0);
2862   /* This generates an error if op1 is pointer to incomplete type.  */
2863   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2864     error ("arithmetic on pointer to an incomplete type");
2865
2866   /* This generates an error if op0 is pointer to incomplete type.  */
2867   op1 = c_size_in_bytes (target_type);
2868
2869   /* Divide by the size, in easiest possible way.  */
2870   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2871 }
2872 \f
2873 /* Construct and perhaps optimize a tree representation
2874    for a unary operation.  CODE, a tree_code, specifies the operation
2875    and XARG is the operand.
2876    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2877    the default promotions (such as from short to int).
2878    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2879    allows non-lvalues; this is only used to handle conversion of non-lvalue
2880    arrays to pointers in C99.  */
2881
2882 tree
2883 build_unary_op (enum tree_code code, tree xarg, int flag)
2884 {
2885   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2886   tree arg = xarg;
2887   tree argtype = 0;
2888   enum tree_code typecode;
2889   tree val;
2890   int noconvert = flag;
2891   const char *invalid_op_diag;
2892
2893   if (code != ADDR_EXPR)
2894     arg = require_complete_type (arg);
2895
2896   typecode = TREE_CODE (TREE_TYPE (arg));
2897   if (typecode == ERROR_MARK)
2898     return error_mark_node;
2899   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2900     typecode = INTEGER_TYPE;
2901
2902   if ((invalid_op_diag
2903        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2904     {
2905       error (invalid_op_diag);
2906       return error_mark_node;
2907     }
2908
2909   switch (code)
2910     {
2911     case CONVERT_EXPR:
2912       /* This is used for unary plus, because a CONVERT_EXPR
2913          is enough to prevent anybody from looking inside for
2914          associativity, but won't generate any code.  */
2915       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2916             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2917             || typecode == VECTOR_TYPE))
2918         {
2919           error ("wrong type argument to unary plus");
2920           return error_mark_node;
2921         }
2922       else if (!noconvert)
2923         arg = default_conversion (arg);
2924       arg = non_lvalue (arg);
2925       break;
2926
2927     case NEGATE_EXPR:
2928       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2929             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2930             || typecode == VECTOR_TYPE))
2931         {
2932           error ("wrong type argument to unary minus");
2933           return error_mark_node;
2934         }
2935       else if (!noconvert)
2936         arg = default_conversion (arg);
2937       break;
2938
2939     case BIT_NOT_EXPR:
2940       /* ~ works on integer types and non float vectors. */
2941       if (typecode == INTEGER_TYPE
2942           || (typecode == VECTOR_TYPE
2943               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2944         {
2945           if (!noconvert)
2946             arg = default_conversion (arg);
2947         }
2948       else if (typecode == COMPLEX_TYPE)
2949         {
2950           code = CONJ_EXPR;
2951           if (pedantic)
2952             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2953           if (!noconvert)
2954             arg = default_conversion (arg);
2955         }
2956       else
2957         {
2958           error ("wrong type argument to bit-complement");
2959           return error_mark_node;
2960         }
2961       break;
2962
2963     case ABS_EXPR:
2964       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2965         {
2966           error ("wrong type argument to abs");
2967           return error_mark_node;
2968         }
2969       else if (!noconvert)
2970         arg = default_conversion (arg);
2971       break;
2972
2973     case CONJ_EXPR:
2974       /* Conjugating a real value is a no-op, but allow it anyway.  */
2975       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2976             || typecode == COMPLEX_TYPE))
2977         {
2978           error ("wrong type argument to conjugation");
2979           return error_mark_node;
2980         }
2981       else if (!noconvert)
2982         arg = default_conversion (arg);
2983       break;
2984
2985     case TRUTH_NOT_EXPR:
2986       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
2987           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2988           && typecode != COMPLEX_TYPE)
2989         {
2990           error ("wrong type argument to unary exclamation mark");
2991           return error_mark_node;
2992         }
2993       arg = c_objc_common_truthvalue_conversion (arg);
2994       return invert_truthvalue (arg);
2995
2996     case REALPART_EXPR:
2997       if (TREE_CODE (arg) == COMPLEX_CST)
2998         return TREE_REALPART (arg);
2999       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3000         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3001       else
3002         return arg;
3003
3004     case IMAGPART_EXPR:
3005       if (TREE_CODE (arg) == COMPLEX_CST)
3006         return TREE_IMAGPART (arg);
3007       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3008         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3009       else
3010         return convert (TREE_TYPE (arg), integer_zero_node);
3011
3012     case PREINCREMENT_EXPR:
3013     case POSTINCREMENT_EXPR:
3014     case PREDECREMENT_EXPR:
3015     case POSTDECREMENT_EXPR:
3016
3017       /* Increment or decrement the real part of the value,
3018          and don't change the imaginary part.  */
3019       if (typecode == COMPLEX_TYPE)
3020         {
3021           tree real, imag;
3022
3023           if (pedantic)
3024             pedwarn ("ISO C does not support %<++%> and %<--%>"
3025                      " on complex types");
3026
3027           arg = stabilize_reference (arg);
3028           real = build_unary_op (REALPART_EXPR, arg, 1);
3029           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3030           real = build_unary_op (code, real, 1);
3031           if (real == error_mark_node || imag == error_mark_node)
3032             return error_mark_node;
3033           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3034                          real, imag);
3035         }
3036
3037       /* Report invalid types.  */
3038
3039       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3040           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3041         {
3042           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3043             error ("wrong type argument to increment");
3044           else
3045             error ("wrong type argument to decrement");
3046
3047           return error_mark_node;
3048         }
3049
3050       {
3051         tree inc;
3052         tree result_type = TREE_TYPE (arg);
3053
3054         arg = get_unwidened (arg, 0);
3055         argtype = TREE_TYPE (arg);
3056
3057         /* Compute the increment.  */
3058
3059         if (typecode == POINTER_TYPE)
3060           {
3061             /* If pointer target is an undefined struct,
3062                we just cannot know how to do the arithmetic.  */
3063             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3064               {
3065                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3066                   error ("increment of pointer to unknown structure");
3067                 else
3068                   error ("decrement of pointer to unknown structure");
3069               }
3070             else if ((pedantic || warn_pointer_arith)
3071                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3072                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
3073               {
3074                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3075                   pedwarn ("wrong type argument to increment");
3076                 else
3077                   pedwarn ("wrong type argument to decrement");
3078               }
3079
3080             inc = c_size_in_bytes (TREE_TYPE (result_type));
3081             inc = fold_convert (sizetype, inc);
3082           }
3083         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3084           {
3085             /* For signed fract types, we invert ++ to -- or
3086                -- to ++, and change inc from 1 to -1, because
3087                it is not possible to represent 1 in signed fract constants.
3088                For unsigned fract types, the result always overflows and
3089                we get an undefined (original) or the maximum value.  */
3090             if (code == PREINCREMENT_EXPR)
3091               code = PREDECREMENT_EXPR;
3092             else if (code == PREDECREMENT_EXPR)
3093               code = PREINCREMENT_EXPR;
3094             else if (code == POSTINCREMENT_EXPR)
3095               code = POSTDECREMENT_EXPR;
3096             else /* code == POSTDECREMENT_EXPR  */
3097               code = POSTINCREMENT_EXPR;
3098
3099             inc = integer_minus_one_node;
3100             inc = convert (argtype, inc);
3101           }
3102         else
3103           {
3104             inc = integer_one_node;
3105             inc = convert (argtype, inc);
3106           }
3107
3108         /* Complain about anything else that is not a true lvalue.  */
3109         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3110                                     || code == POSTINCREMENT_EXPR)
3111                                    ? lv_increment
3112                                    : lv_decrement)))
3113           return error_mark_node;
3114
3115         /* Report a read-only lvalue.  */
3116         if (TREE_READONLY (arg))
3117           {
3118             readonly_error (arg,
3119                             ((code == PREINCREMENT_EXPR
3120                               || code == POSTINCREMENT_EXPR)
3121                              ? lv_increment : lv_decrement));
3122             return error_mark_node;
3123           }
3124
3125         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3126           val = boolean_increment (code, arg);
3127         else
3128           val = build2 (code, TREE_TYPE (arg), arg, inc);
3129         TREE_SIDE_EFFECTS (val) = 1;
3130         val = convert (result_type, val);
3131         if (TREE_CODE (val) != code)
3132           TREE_NO_WARNING (val) = 1;
3133         return val;
3134       }
3135
3136     case ADDR_EXPR:
3137       /* Note that this operation never does default_conversion.  */
3138
3139       /* Let &* cancel out to simplify resulting code.  */
3140       if (TREE_CODE (arg) == INDIRECT_REF)
3141         {
3142           /* Don't let this be an lvalue.  */
3143           if (lvalue_p (TREE_OPERAND (arg, 0)))
3144             return non_lvalue (TREE_OPERAND (arg, 0));
3145           return TREE_OPERAND (arg, 0);
3146         }
3147
3148       /* For &x[y], return x+y */
3149       if (TREE_CODE (arg) == ARRAY_REF)
3150         {
3151           tree op0 = TREE_OPERAND (arg, 0);
3152           if (!c_mark_addressable (op0))
3153             return error_mark_node;
3154           return build_binary_op (PLUS_EXPR,
3155                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3156                                    ? array_to_pointer_conversion (op0)
3157                                    : op0),
3158                                   TREE_OPERAND (arg, 1), 1);
3159         }
3160
3161       /* Anything not already handled and not a true memory reference
3162          or a non-lvalue array is an error.  */
3163       else if (typecode != FUNCTION_TYPE && !flag
3164                && !lvalue_or_else (arg, lv_addressof))
3165         return error_mark_node;
3166
3167       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3168       argtype = TREE_TYPE (arg);
3169
3170       /* If the lvalue is const or volatile, merge that into the type
3171          to which the address will point.  Note that you can't get a
3172          restricted pointer by taking the address of something, so we
3173          only have to deal with `const' and `volatile' here.  */
3174       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3175           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3176           argtype = c_build_type_variant (argtype,
3177                                           TREE_READONLY (arg),
3178                                           TREE_THIS_VOLATILE (arg));
3179
3180       if (!c_mark_addressable (arg))
3181         return error_mark_node;
3182
3183       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3184                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3185
3186       argtype = build_pointer_type (argtype);
3187
3188       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3189          when we have proper support for integer constant expressions.  */
3190       val = get_base_address (arg);
3191       if (val && TREE_CODE (val) == INDIRECT_REF
3192           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3193         {
3194           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3195
3196           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3197           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3198         }
3199
3200       val = build1 (ADDR_EXPR, argtype, arg);
3201
3202       return val;
3203
3204     default:
3205       gcc_unreachable ();
3206     }
3207
3208   if (argtype == 0)
3209     argtype = TREE_TYPE (arg);
3210   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3211                                 : fold_build1 (code, argtype, arg);
3212 }
3213
3214 /* Return nonzero if REF is an lvalue valid for this language.
3215    Lvalues can be assigned, unless their type has TYPE_READONLY.
3216    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3217
3218 static int
3219 lvalue_p (const_tree ref)
3220 {
3221   const enum tree_code code = TREE_CODE (ref);
3222
3223   switch (code)
3224     {
3225     case REALPART_EXPR:
3226     case IMAGPART_EXPR:
3227     case COMPONENT_REF:
3228       return lvalue_p (TREE_OPERAND (ref, 0));
3229
3230     case COMPOUND_LITERAL_EXPR:
3231     case STRING_CST:
3232       return 1;
3233
3234     case INDIRECT_REF:
3235     case ARRAY_REF:
3236     case VAR_DECL:
3237     case PARM_DECL:
3238     case RESULT_DECL:
3239     case ERROR_MARK:
3240       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3241               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3242
3243     case BIND_EXPR:
3244       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3245
3246     default:
3247       return 0;
3248     }
3249 }
3250 \f
3251 /* Give an error for storing in something that is 'const'.  */
3252
3253 static void
3254 readonly_error (tree arg, enum lvalue_use use)
3255 {
3256   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3257               || use == lv_asm);
3258   /* Using this macro rather than (for example) arrays of messages
3259      ensures that all the format strings are checked at compile
3260      time.  */
3261 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3262                                    : (use == lv_increment ? (I)         \
3263                                    : (use == lv_decrement ? (D) : (AS))))
3264   if (TREE_CODE (arg) == COMPONENT_REF)
3265     {
3266       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3267         readonly_error (TREE_OPERAND (arg, 0), use);
3268       else
3269         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3270                              G_("increment of read-only member %qD"),
3271                              G_("decrement of read-only member %qD"),
3272                              G_("read-only member %qD used as %<asm%> output")),
3273                TREE_OPERAND (arg, 1));
3274     }
3275   else if (TREE_CODE (arg) == VAR_DECL)
3276     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3277                          G_("increment of read-only variable %qD"),
3278                          G_("decrement of read-only variable %qD"),
3279                          G_("read-only variable %qD used as %<asm%> output")),
3280            arg);
3281   else
3282     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3283                          G_("increment of read-only location %qE"),
3284                          G_("decrement of read-only location %qE"),
3285                          G_("read-only location %qE used as %<asm%> output")),
3286            arg);
3287 }
3288
3289
3290 /* Return nonzero if REF is an lvalue valid for this language;
3291    otherwise, print an error message and return zero.  USE says
3292    how the lvalue is being used and so selects the error message.  */
3293
3294 static int
3295 lvalue_or_else (const_tree ref, enum lvalue_use use)
3296 {
3297   int win = lvalue_p (ref);
3298
3299   if (!win)
3300     lvalue_error (use);
3301
3302   return win;
3303 }
3304 \f
3305 /* Mark EXP saying that we need to be able to take the
3306    address of it; it should not be allocated in a register.
3307    Returns true if successful.  */
3308
3309 bool
3310 c_mark_addressable (tree exp)
3311 {
3312   tree x = exp;
3313
3314   while (1)
3315     switch (TREE_CODE (x))
3316       {
3317       case COMPONENT_REF:
3318         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3319           {
3320             error
3321               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3322             return false;
3323           }
3324
3325         /* ... fall through ...  */
3326
3327       case ADDR_EXPR:
3328       case ARRAY_REF:
3329       case REALPART_EXPR:
3330       case IMAGPART_EXPR:
3331         x = TREE_OPERAND (x, 0);
3332         break;
3333
3334       case COMPOUND_LITERAL_EXPR:
3335       case CONSTRUCTOR:
3336         TREE_ADDRESSABLE (x) = 1;
3337         return true;
3338
3339       case VAR_DECL:
3340       case CONST_DECL:
3341       case PARM_DECL:
3342       case RESULT_DECL:
3343         if (C_DECL_REGISTER (x)
3344             && DECL_NONLOCAL (x))
3345           {
3346             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3347               {
3348                 error
3349                   ("global register variable %qD used in nested function", x);
3350                 return false;
3351               }
3352             pedwarn ("register variable %qD used in nested function", x);
3353           }
3354         else if (C_DECL_REGISTER (x))
3355           {
3356             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3357               error ("address of global register variable %qD requested", x);
3358             else
3359               error ("address of register variable %qD requested", x);
3360             return false;
3361           }
3362
3363         /* drops in */
3364       case FUNCTION_DECL:
3365         TREE_ADDRESSABLE (x) = 1;
3366         /* drops out */
3367       default:
3368         return true;
3369     }
3370 }
3371 \f
3372 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3373
3374 tree
3375 build_conditional_expr (tree ifexp, tree op1, tree op2)
3376 {
3377   tree type1;
3378   tree type2;
3379   enum tree_code code1;
3380   enum tree_code code2;
3381   tree result_type = NULL;
3382   tree orig_op1 = op1, orig_op2 = op2;
3383
3384   /* Promote both alternatives.  */
3385
3386   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3387     op1 = default_conversion (op1);
3388   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3389     op2 = default_conversion (op2);
3390
3391   if (TREE_CODE (ifexp) == ERROR_MARK
3392       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3393       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3394     return error_mark_node;
3395
3396   type1 = TREE_TYPE (op1);
3397   code1 = TREE_CODE (type1);
3398   type2 = TREE_TYPE (op2);
3399   code2 = TREE_CODE (type2);
3400
3401   /* C90 does not permit non-lvalue arrays in conditional expressions.
3402      In C99 they will be pointers by now.  */
3403   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3404     {
3405       error ("non-lvalue array in conditional expression");
3406       return error_mark_node;
3407     }
3408
3409   /* Quickly detect the usual case where op1 and op2 have the same type
3410      after promotion.  */
3411   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3412     {
3413       if (type1 == type2)
3414         result_type = type1;
3415       else
3416         result_type = TYPE_MAIN_VARIANT (type1);
3417     }
3418   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3419             || code1 == COMPLEX_TYPE)
3420            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3421                || code2 == COMPLEX_TYPE))
3422     {
3423       result_type = c_common_type (type1, type2);
3424
3425       /* If -Wsign-compare, warn here if type1 and type2 have
3426          different signedness.  We'll promote the signed to unsigned
3427          and later code won't know it used to be different.
3428          Do this check on the original types, so that explicit casts
3429          will be considered, but default promotions won't.  */
3430       if (warn_sign_compare && !skip_evaluation)
3431         {
3432           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3433           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3434
3435           if (unsigned_op1 ^ unsigned_op2)
3436             {
3437               bool ovf;
3438
3439               /* Do not warn if the result type is signed, since the
3440                  signed type will only be chosen if it can represent
3441                  all the values of the unsigned type.  */
3442               if (!TYPE_UNSIGNED (result_type))
3443                 /* OK */;
3444               /* Do not warn if the signed quantity is an unsuffixed
3445                  integer literal (or some static constant expression
3446                  involving such literals) and it is non-negative.  */
3447               else if ((unsigned_op2
3448                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3449                        || (unsigned_op1
3450                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3451                 /* OK */;
3452               else
3453                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3454             }
3455         }
3456     }
3457   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3458     {
3459       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3460         pedwarn ("ISO C forbids conditional expr with only one void side");
3461       result_type = void_type_node;
3462     }
3463   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3464     {
3465       if (comp_target_types (type1, type2))
3466         result_type = common_pointer_type (type1, type2);
3467       else if (null_pointer_constant_p (orig_op1))
3468         result_type = qualify_type (type2, type1);
3469       else if (null_pointer_constant_p (orig_op2))
3470         result_type = qualify_type (type1, type2);
3471       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3472         {
3473           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3474             pedwarn ("ISO C forbids conditional expr between "
3475                      "%<void *%> and function pointer");
3476           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3477                                                           TREE_TYPE (type2)));
3478         }
3479       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3480         {
3481           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3482             pedwarn ("ISO C forbids conditional expr between "
3483                      "%<void *%> and function pointer");
3484           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3485                                                           TREE_TYPE (type1)));
3486         }
3487       else
3488         {
3489           pedwarn ("pointer type mismatch in conditional expression");
3490           result_type = build_pointer_type (void_type_node);
3491         }
3492     }
3493   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3494     {
3495       if (!null_pointer_constant_p (orig_op2))
3496         pedwarn ("pointer/integer type mismatch in conditional expression");
3497       else
3498         {
3499           op2 = null_pointer_node;
3500         }
3501       result_type = type1;
3502     }
3503   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3504     {
3505       if (!null_pointer_constant_p (orig_op1))
3506         pedwarn ("pointer/integer type mismatch in conditional expression");
3507       else
3508         {
3509           op1 = null_pointer_node;
3510         }
3511       result_type = type2;
3512     }
3513
3514   if (!result_type)
3515     {
3516       if (flag_cond_mismatch)
3517         result_type = void_type_node;
3518       else
3519         {
3520           error ("type mismatch in conditional expression");
3521           return error_mark_node;
3522         }
3523     }
3524
3525   /* Merge const and volatile flags of the incoming types.  */
3526   result_type
3527     = build_type_variant (result_type,
3528                           TREE_READONLY (op1) || TREE_READONLY (op2),
3529                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3530
3531   if (result_type != TREE_TYPE (op1))
3532     op1 = convert_and_check (result_type, op1);
3533   if (result_type != TREE_TYPE (op2))
3534     op2 = convert_and_check (result_type, op2);
3535
3536   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3537 }
3538 \f
3539 /* Return a compound expression that performs two expressions and
3540    returns the value of the second of them.  */
3541
3542 tree
3543 build_compound_expr (tree expr1, tree expr2)
3544 {
3545   if (!TREE_SIDE_EFFECTS (expr1))
3546     {
3547       /* The left-hand operand of a comma expression is like an expression
3548          statement: with -Wunused, we should warn if it doesn't have
3549          any side-effects, unless it was explicitly cast to (void).  */
3550       if (warn_unused_value)
3551         {
3552           if (VOID_TYPE_P (TREE_TYPE (expr1))
3553               && (TREE_CODE (expr1) == NOP_EXPR
3554                   || TREE_CODE (expr1) == CONVERT_EXPR))
3555             ; /* (void) a, b */
3556           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3557                    && TREE_CODE (expr1) == COMPOUND_EXPR
3558                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3559                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
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 (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3632                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3633           break;
3634
3635       if (field)
3636         {
3637           tree t;
3638
3639           if (pedantic)
3640             pedwarn ("ISO C forbids casts to union type");
3641           t = digest_init (type,
3642                            build_constructor_single (type, field, value),
3643                            true, 0);
3644           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3645           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3646           return t;
3647         }
3648       error ("cast to union type from type not present in union");
3649       return error_mark_node;
3650     }
3651   else
3652     {
3653       tree otype, ovalue;
3654
3655       if (type == void_type_node)
3656         return build1 (CONVERT_EXPR, type, value);
3657
3658       otype = TREE_TYPE (value);
3659
3660       /* Optionally warn about potentially worrisome casts.  */
3661
3662       if (warn_cast_qual
3663           && TREE_CODE (type) == POINTER_TYPE
3664           && TREE_CODE (otype) == POINTER_TYPE)
3665         {
3666           tree in_type = type;
3667           tree in_otype = otype;
3668           int added = 0;
3669           int discarded = 0;
3670
3671           /* Check that the qualifiers on IN_TYPE are a superset of
3672              the qualifiers of IN_OTYPE.  The outermost level of
3673              POINTER_TYPE nodes is uninteresting and we stop as soon
3674              as we hit a non-POINTER_TYPE node on either type.  */
3675           do
3676             {
3677               in_otype = TREE_TYPE (in_otype);
3678               in_type = TREE_TYPE (in_type);
3679
3680               /* GNU C allows cv-qualified function types.  'const'
3681                  means the function is very pure, 'volatile' means it
3682                  can't return.  We need to warn when such qualifiers
3683                  are added, not when they're taken away.  */
3684               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3685                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3686                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3687               else
3688                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3689             }
3690           while (TREE_CODE (in_type) == POINTER_TYPE
3691                  && TREE_CODE (in_otype) == POINTER_TYPE);
3692
3693           if (added)
3694             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3695
3696           if (discarded)
3697             /* There are qualifiers present in IN_OTYPE that are not
3698                present in IN_TYPE.  */
3699             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3700         }
3701
3702       /* Warn about possible alignment problems.  */
3703       if (STRICT_ALIGNMENT
3704           && TREE_CODE (type) == POINTER_TYPE
3705           && TREE_CODE (otype) == POINTER_TYPE
3706           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3707           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3708           /* Don't warn about opaque types, where the actual alignment
3709              restriction is unknown.  */
3710           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3711                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3712                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3713           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3714         warning (OPT_Wcast_align,
3715                  "cast increases required alignment of target type");
3716
3717       if (TREE_CODE (type) == INTEGER_TYPE
3718           && TREE_CODE (otype) == POINTER_TYPE
3719           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3720       /* Unlike conversion of integers to pointers, where the
3721          warning is disabled for converting constants because
3722          of cases such as SIG_*, warn about converting constant
3723          pointers to integers. In some cases it may cause unwanted
3724          sign extension, and a warning is appropriate.  */
3725         warning (OPT_Wpointer_to_int_cast,
3726                  "cast from pointer to integer of different size");
3727
3728       if (TREE_CODE (value) == CALL_EXPR
3729           && TREE_CODE (type) != TREE_CODE (otype))
3730         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3731                  "to non-matching type %qT", otype, type);
3732
3733       if (TREE_CODE (type) == POINTER_TYPE
3734           && TREE_CODE (otype) == INTEGER_TYPE
3735           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3736           /* Don't warn about converting any constant.  */
3737           && !TREE_CONSTANT (value))
3738         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3739                  "of different size");
3740
3741       if (warn_strict_aliasing <= 2)
3742         strict_aliasing_warning (otype, type, expr);
3743
3744       /* If pedantic, warn for conversions between function and object
3745          pointer types, except for converting a null pointer constant
3746          to function pointer type.  */
3747       if (pedantic
3748           && TREE_CODE (type) == POINTER_TYPE
3749           && TREE_CODE (otype) == POINTER_TYPE
3750           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3751           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3752         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3753
3754       if (pedantic
3755           && TREE_CODE (type) == POINTER_TYPE
3756           && TREE_CODE (otype) == POINTER_TYPE
3757           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3758           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3759           && !null_pointer_constant_p (value))
3760         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3761
3762       ovalue = value;
3763       value = convert (type, value);
3764
3765       /* Ignore any integer overflow caused by the cast.  */
3766       if (TREE_CODE (value) == INTEGER_CST)
3767         {
3768           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3769             {
3770               if (!TREE_OVERFLOW (value))
3771                 {
3772                   /* Avoid clobbering a shared constant.  */
3773                   value = copy_node (value);
3774                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3775                 }
3776             }
3777           else if (TREE_OVERFLOW (value))
3778             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3779             value = build_int_cst_wide (TREE_TYPE (value),
3780                                         TREE_INT_CST_LOW (value),
3781                                         TREE_INT_CST_HIGH (value));
3782         }
3783     }
3784
3785   /* Don't let a cast be an lvalue.  */
3786   if (value == expr)
3787     value = non_lvalue (value);
3788
3789   return value;
3790 }
3791
3792 /* Interpret a cast of expression EXPR to type TYPE.  */
3793 tree
3794 c_cast_expr (struct c_type_name *type_name, tree expr)
3795 {
3796   tree type;
3797   int saved_wsp = warn_strict_prototypes;
3798
3799   /* This avoids warnings about unprototyped casts on
3800      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3801   if (TREE_CODE (expr) == INTEGER_CST)
3802     warn_strict_prototypes = 0;
3803   type = groktypename (type_name);
3804   warn_strict_prototypes = saved_wsp;
3805
3806   return build_c_cast (type, expr);
3807 }
3808 \f
3809 /* Build an assignment expression of lvalue LHS from value RHS.
3810    MODIFYCODE is the code for a binary operator that we use
3811    to combine the old value of LHS with RHS to get the new value.
3812    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3813
3814 tree
3815 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3816 {
3817   tree result;
3818   tree newrhs;
3819   tree lhstype = TREE_TYPE (lhs);
3820   tree olhstype = lhstype;
3821
3822   /* Types that aren't fully specified cannot be used in assignments.  */
3823   lhs = require_complete_type (lhs);
3824
3825   /* Avoid duplicate error messages from operands that had errors.  */
3826   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3827     return error_mark_node;
3828
3829   if (!lvalue_or_else (lhs, lv_assign))
3830     return error_mark_node;
3831
3832   STRIP_TYPE_NOPS (rhs);
3833
3834   newrhs = rhs;
3835
3836   /* If a binary op has been requested, combine the old LHS value with the RHS
3837      producing the value we should actually store into the LHS.  */
3838
3839   if (modifycode != NOP_EXPR)
3840     {
3841       lhs = stabilize_reference (lhs);
3842       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3843     }
3844
3845   /* Give an error for storing in something that is 'const'.  */
3846
3847   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3848       || ((TREE_CODE (lhstype) == RECORD_TYPE
3849            || TREE_CODE (lhstype) == UNION_TYPE)
3850           && C_TYPE_FIELDS_READONLY (lhstype)))
3851     {
3852       readonly_error (lhs, lv_assign);
3853       return error_mark_node;
3854     }
3855
3856   /* If storing into a structure or union member,
3857      it has probably been given type `int'.
3858      Compute the type that would go with
3859      the actual amount of storage the member occupies.  */
3860
3861   if (TREE_CODE (lhs) == COMPONENT_REF
3862       && (TREE_CODE (lhstype) == INTEGER_TYPE
3863           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3864           || TREE_CODE (lhstype) == REAL_TYPE
3865           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3866     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3867
3868   /* If storing in a field that is in actuality a short or narrower than one,
3869      we must store in the field in its actual type.  */
3870
3871   if (lhstype != TREE_TYPE (lhs))
3872     {
3873       lhs = copy_node (lhs);
3874       TREE_TYPE (lhs) = lhstype;
3875     }
3876
3877   /* Convert new value to destination type.  */
3878
3879   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3880                                    NULL_TREE, NULL_TREE, 0);
3881   if (TREE_CODE (newrhs) == ERROR_MARK)
3882     return error_mark_node;
3883
3884   /* Emit ObjC write barrier, if necessary.  */
3885   if (c_dialect_objc () && flag_objc_gc)
3886     {
3887       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3888       if (result)
3889         return result;
3890     }
3891
3892   /* Scan operands.  */
3893
3894   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3895   TREE_SIDE_EFFECTS (result) = 1;
3896
3897   /* If we got the LHS in a different type for storing in,
3898      convert the result back to the nominal type of LHS
3899      so that the value we return always has the same type
3900      as the LHS argument.  */
3901
3902   if (olhstype == TREE_TYPE (result))
3903     return result;
3904   return convert_for_assignment (olhstype, result, ic_assign,
3905                                  NULL_TREE, NULL_TREE, 0);
3906 }
3907 \f
3908 /* Convert value RHS to type TYPE as preparation for an assignment
3909    to an lvalue of type TYPE.
3910    The real work of conversion is done by `convert'.
3911    The purpose of this function is to generate error messages
3912    for assignments that are not allowed in C.
3913    ERRTYPE says whether it is argument passing, assignment,
3914    initialization or return.
3915
3916    FUNCTION is a tree for the function being called.
3917    PARMNUM is the number of the argument, for printing in error messages.  */
3918
3919 static tree
3920 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3921                         tree fundecl, tree function, int parmnum)
3922 {
3923   enum tree_code codel = TREE_CODE (type);
3924   tree rhstype;
3925   enum tree_code coder;
3926   tree rname = NULL_TREE;
3927   bool objc_ok = false;
3928
3929   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3930     {
3931       tree selector;
3932       /* Change pointer to function to the function itself for
3933          diagnostics.  */
3934       if (TREE_CODE (function) == ADDR_EXPR
3935           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3936         function = TREE_OPERAND (function, 0);
3937
3938       /* Handle an ObjC selector specially for diagnostics.  */
3939       selector = objc_message_selector ();
3940       rname = function;
3941       if (selector && parmnum > 2)
3942         {
3943           rname = selector;
3944           parmnum -= 2;
3945         }
3946     }
3947
3948   /* This macro is used to emit diagnostics to ensure that all format
3949      strings are complete sentences, visible to gettext and checked at
3950      compile time.  */
3951 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3952   do {                                          \
3953     switch (errtype)                            \
3954       {                                         \
3955       case ic_argpass:                          \
3956         pedwarn (AR, parmnum, rname);           \
3957         break;                                  \
3958       case ic_argpass_nonproto:                 \
3959         warning (0, AR, parmnum, rname);                \
3960         break;                                  \
3961       case ic_assign:                           \
3962         pedwarn (AS);                           \
3963         break;                                  \
3964       case ic_init:                             \
3965         pedwarn (IN);                           \
3966         break;                                  \
3967       case ic_return:                           \
3968         pedwarn (RE);                           \
3969         break;                                  \
3970       default:                                  \
3971         gcc_unreachable ();                     \
3972       }                                         \
3973   } while (0)
3974
3975   STRIP_TYPE_NOPS (rhs);
3976
3977   if (optimize && TREE_CODE (rhs) == VAR_DECL
3978            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3979     rhs = decl_constant_value_for_broken_optimization (rhs);
3980
3981   rhstype = TREE_TYPE (rhs);
3982   coder = TREE_CODE (rhstype);
3983
3984   if (coder == ERROR_MARK)
3985     return error_mark_node;
3986
3987   if (c_dialect_objc ())
3988     {
3989       int parmno;
3990
3991       switch (errtype)
3992         {
3993         case ic_return:
3994           parmno = 0;
3995           break;
3996
3997         case ic_assign:
3998           parmno = -1;
3999           break;
4000
4001         case ic_init:
4002           parmno = -2;
4003           break;
4004
4005         default:
4006           parmno = parmnum;
4007           break;
4008         }
4009
4010       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4011     }
4012
4013   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4014     return rhs;
4015
4016   if (coder == VOID_TYPE)
4017     {
4018       /* Except for passing an argument to an unprototyped function,
4019          this is a constraint violation.  When passing an argument to
4020          an unprototyped function, it is compile-time undefined;
4021          making it a constraint in that case was rejected in
4022          DR#252.  */
4023       error ("void value not ignored as it ought to be");
4024       return error_mark_node;
4025     }
4026   rhs = require_complete_type (rhs);
4027   if (rhs == error_mark_node)
4028     return error_mark_node;
4029   /* A type converts to a reference to it.
4030      This code doesn't fully support references, it's just for the
4031      special case of va_start and va_copy.  */
4032   if (codel == REFERENCE_TYPE
4033       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4034     {
4035       if (!lvalue_p (rhs))
4036         {
4037           error ("cannot pass rvalue to reference parameter");
4038           return error_mark_node;
4039         }
4040       if (!c_mark_addressable (rhs))
4041         return error_mark_node;
4042       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4043
4044       /* We already know that these two types are compatible, but they
4045          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4046          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4047          likely to be va_list, a typedef to __builtin_va_list, which
4048          is different enough that it will cause problems later.  */
4049       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4050         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4051
4052       rhs = build1 (NOP_EXPR, type, rhs);
4053       return rhs;
4054     }
4055   /* Some types can interconvert without explicit casts.  */
4056   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4057            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4058     return convert (type, rhs);
4059   /* Arithmetic types all interconvert, and enum is treated like int.  */
4060   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4061             || codel == FIXED_POINT_TYPE
4062             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4063             || codel == BOOLEAN_TYPE)
4064            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4065                || coder == FIXED_POINT_TYPE
4066                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4067                || coder == BOOLEAN_TYPE))
4068     return convert_and_check (type, rhs);
4069
4070   /* Aggregates in different TUs might need conversion.  */
4071   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4072       && codel == coder
4073       && comptypes (type, rhstype))
4074     return convert_and_check (type, rhs);
4075
4076   /* Conversion to a transparent union from its member types.
4077      This applies only to function arguments.  */
4078   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4079       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4080     {
4081       tree memb, marginal_memb = NULL_TREE;
4082
4083       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4084         {
4085           tree memb_type = TREE_TYPE (memb);
4086
4087           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4088                          TYPE_MAIN_VARIANT (rhstype)))
4089             break;
4090
4091           if (TREE_CODE (memb_type) != POINTER_TYPE)
4092             continue;
4093
4094           if (coder == POINTER_TYPE)
4095             {
4096               tree ttl = TREE_TYPE (memb_type);
4097               tree ttr = TREE_TYPE (rhstype);
4098
4099               /* Any non-function converts to a [const][volatile] void *
4100                  and vice versa; otherwise, targets must be the same.
4101                  Meanwhile, the lhs target must have all the qualifiers of
4102                  the rhs.  */
4103               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4104                   || comp_target_types (memb_type, rhstype))
4105                 {
4106                   /* If this type won't generate any warnings, use it.  */
4107                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4108                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4109                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4110                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4111                              == TYPE_QUALS (ttr))
4112                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4113                              == TYPE_QUALS (ttl))))
4114                     break;
4115
4116                   /* Keep looking for a better type, but remember this one.  */
4117                   if (!marginal_memb)
4118                     marginal_memb = memb;
4119                 }
4120             }
4121
4122           /* Can convert integer zero to any pointer type.  */
4123           if (null_pointer_constant_p (rhs))
4124             {
4125               rhs = null_pointer_node;
4126               break;
4127             }
4128         }
4129
4130       if (memb || marginal_memb)
4131         {
4132           if (!memb)
4133             {
4134               /* We have only a marginally acceptable member type;
4135                  it needs a warning.  */
4136               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4137               tree ttr = TREE_TYPE (rhstype);
4138
4139               /* Const and volatile mean something different for function
4140                  types, so the usual warnings are not appropriate.  */
4141               if (TREE_CODE (ttr) == FUNCTION_TYPE
4142                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4143                 {
4144                   /* Because const and volatile on functions are
4145                      restrictions that say the function will not do
4146                      certain things, it is okay to use a const or volatile
4147                      function where an ordinary one is wanted, but not
4148                      vice-versa.  */
4149                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4150                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4151                                             "makes qualified function "
4152                                             "pointer from unqualified"),
4153                                          G_("assignment makes qualified "
4154                                             "function pointer from "
4155                                             "unqualified"),
4156                                          G_("initialization makes qualified "
4157                                             "function pointer from "
4158                                             "unqualified"),
4159                                          G_("return makes qualified function "
4160                                             "pointer from unqualified"));
4161                 }
4162               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4163                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4164                                         "qualifiers from pointer target type"),
4165                                      G_("assignment discards qualifiers "
4166                                         "from pointer target type"),
4167                                      G_("initialization discards qualifiers "
4168                                         "from pointer target type"),
4169                                      G_("return discards qualifiers from "
4170                                         "pointer target type"));
4171
4172               memb = marginal_memb;
4173             }
4174
4175           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4176             pedwarn ("ISO C prohibits argument conversion to union type");
4177
4178           rhs = fold_convert (TREE_TYPE (memb), rhs);
4179           return build_constructor_single (type, memb, rhs);
4180         }
4181     }
4182
4183   /* Conversions among pointers */
4184   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4185            && (coder == codel))
4186     {
4187       tree ttl = TREE_TYPE (type);
4188       tree ttr = TREE_TYPE (rhstype);
4189       tree mvl = ttl;
4190       tree mvr = ttr;
4191       bool is_opaque_pointer;
4192       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4193
4194       if (TREE_CODE (mvl) != ARRAY_TYPE)
4195         mvl = TYPE_MAIN_VARIANT (mvl);
4196       if (TREE_CODE (mvr) != ARRAY_TYPE)
4197         mvr = TYPE_MAIN_VARIANT (mvr);
4198       /* Opaque pointers are treated like void pointers.  */
4199       is_opaque_pointer = (targetm.vector_opaque_p (type)
4200                            || targetm.vector_opaque_p (rhstype))
4201         && TREE_CODE (ttl) == VECTOR_TYPE
4202         && TREE_CODE (ttr) == VECTOR_TYPE;
4203
4204       /* C++ does not allow the implicit conversion void* -> T*.  However,
4205          for the purpose of reducing the number of false positives, we
4206          tolerate the special case of
4207
4208                 int *p = NULL;
4209
4210          where NULL is typically defined in C to be '(void *) 0'.  */
4211       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4212         warning (OPT_Wc___compat, "request for implicit conversion from "
4213                  "%qT to %qT not permitted in C++", rhstype, type);
4214
4215       /* Check if the right-hand side has a format attribute but the
4216          left-hand side doesn't.  */
4217       if (warn_missing_format_attribute
4218           && check_missing_format_attribute (type, rhstype))
4219         {
4220           switch (errtype)
4221           {
4222           case ic_argpass:
4223           case ic_argpass_nonproto:
4224             warning (OPT_Wmissing_format_attribute,
4225                      "argument %d of %qE might be "
4226                      "a candidate for a format attribute",
4227                      parmnum, rname);
4228             break;
4229           case ic_assign:
4230             warning (OPT_Wmissing_format_attribute,
4231                      "assignment left-hand side might be "
4232                      "a candidate for a format attribute");
4233             break;
4234           case ic_init:
4235             warning (OPT_Wmissing_format_attribute,
4236                      "initialization left-hand side might be "
4237                      "a candidate for a format attribute");
4238             break;
4239           case ic_return:
4240             warning (OPT_Wmissing_format_attribute,
4241                      "return type might be "
4242                      "a candidate for a format attribute");
4243             break;
4244           default:
4245             gcc_unreachable ();
4246           }
4247         }
4248
4249       /* Any non-function converts to a [const][volatile] void *
4250          and vice versa; otherwise, targets must be the same.
4251          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4252       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4253           || (target_cmp = comp_target_types (type, rhstype))
4254           || is_opaque_pointer
4255           || (c_common_unsigned_type (mvl)
4256               == c_common_unsigned_type (mvr)))
4257         {
4258           if (pedantic
4259               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4260                   ||
4261                   (VOID_TYPE_P (ttr)
4262                    && !null_pointer_constant_p (rhs)
4263                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4264             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4265                                     "%qE between function pointer "
4266                                     "and %<void *%>"),
4267                                  G_("ISO C forbids assignment between "
4268                                     "function pointer and %<void *%>"),
4269                                  G_("ISO C forbids initialization between "
4270                                     "function pointer and %<void *%>"),
4271                                  G_("ISO C forbids return between function "
4272                                     "pointer and %<void *%>"));
4273           /* Const and volatile mean something different for function types,
4274              so the usual warnings are not appropriate.  */
4275           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4276                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4277             {
4278               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4279                 {
4280                   /* Types differing only by the presence of the 'volatile'
4281                      qualifier are acceptable if the 'volatile' has been added
4282                      in by the Objective-C EH machinery.  */
4283                   if (!objc_type_quals_match (ttl, ttr))
4284                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4285                                             "qualifiers from pointer target type"),
4286                                          G_("assignment discards qualifiers "
4287                                             "from pointer target type"),
4288                                          G_("initialization discards qualifiers "
4289                                             "from pointer target type"),
4290                                          G_("return discards qualifiers from "
4291                                             "pointer target type"));
4292                 }
4293               /* If this is not a case of ignoring a mismatch in signedness,
4294                  no warning.  */
4295               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4296                        || target_cmp)
4297                 ;
4298               /* If there is a mismatch, do warn.  */
4299               else if (warn_pointer_sign)
4300                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4301                                         "%d of %qE differ in signedness"),
4302                                      G_("pointer targets in assignment "
4303                                         "differ in signedness"),
4304                                      G_("pointer targets in initialization "
4305                                         "differ in signedness"),
4306                                      G_("pointer targets in return differ "
4307                                         "in signedness"));
4308             }
4309           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4310                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4311             {
4312               /* Because const and volatile on functions are restrictions
4313                  that say the function will not do certain things,
4314                  it is okay to use a const or volatile function
4315                  where an ordinary one is wanted, but not vice-versa.  */
4316               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4317                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4318                                         "qualified function pointer "
4319                                         "from unqualified"),
4320                                      G_("assignment makes qualified function "
4321                                         "pointer from unqualified"),
4322                                      G_("initialization makes qualified "
4323                                         "function pointer from unqualified"),
4324                                      G_("return makes qualified function "
4325                                         "pointer from unqualified"));
4326             }
4327         }
4328       else
4329         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4330         if (!objc_ok)
4331           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4332                                   "incompatible pointer type"),
4333                                G_("assignment from incompatible pointer type"),
4334                                G_("initialization from incompatible "
4335                                   "pointer type"),
4336                                G_("return from incompatible pointer type"));
4337
4338       return convert (type, rhs);
4339     }
4340   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4341     {
4342       /* ??? This should not be an error when inlining calls to
4343          unprototyped functions.  */
4344       error ("invalid use of non-lvalue array");
4345       return error_mark_node;
4346     }
4347   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4348     {
4349       /* An explicit constant 0 can convert to a pointer,
4350          or one that results from arithmetic, even including
4351          a cast to integer type.  */
4352       if (!null_pointer_constant_p (rhs))
4353         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4354                                 "pointer from integer without a cast"),
4355                              G_("assignment makes pointer from integer "
4356                                 "without a cast"),
4357                              G_("initialization makes pointer from "
4358                                 "integer without a cast"),
4359                              G_("return makes pointer from integer "
4360                                 "without a cast"));
4361
4362       return convert (type, rhs);
4363     }
4364   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4365     {
4366       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4367                               "from pointer without a cast"),
4368                            G_("assignment makes integer from pointer "
4369                               "without a cast"),
4370                            G_("initialization makes integer from pointer "
4371                               "without a cast"),
4372                            G_("return makes integer from pointer "
4373                               "without a cast"));
4374       return convert (type, rhs);
4375     }
4376   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4377     return convert (type, rhs);
4378
4379   switch (errtype)
4380     {
4381     case ic_argpass:
4382     case ic_argpass_nonproto:
4383       /* ??? This should not be an error when inlining calls to
4384          unprototyped functions.  */
4385       error ("incompatible type for argument %d of %qE", parmnum, rname);
4386       break;
4387     case ic_assign:
4388       error ("incompatible types in assignment");
4389       break;
4390     case ic_init:
4391       error ("incompatible types in initialization");
4392       break;
4393     case ic_return:
4394       error ("incompatible types in return");
4395       break;
4396     default:
4397       gcc_unreachable ();
4398     }
4399
4400   return error_mark_node;
4401 }
4402 \f
4403 /* If VALUE is a compound expr all of whose expressions are constant, then
4404    return its value.  Otherwise, return error_mark_node.
4405
4406    This is for handling COMPOUND_EXPRs as initializer elements
4407    which is allowed with a warning when -pedantic is specified.  */
4408
4409 static tree
4410 valid_compound_expr_initializer (tree value, tree endtype)
4411 {
4412   if (TREE_CODE (value) == COMPOUND_EXPR)
4413     {
4414       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4415           == error_mark_node)
4416         return error_mark_node;
4417       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4418                                               endtype);
4419     }
4420   else if (!initializer_constant_valid_p (value, endtype))
4421     return error_mark_node;
4422   else
4423     return value;
4424 }
4425 \f
4426 /* Perform appropriate conversions on the initial value of a variable,
4427    store it in the declaration DECL,
4428    and print any error messages that are appropriate.
4429    If the init is invalid, store an ERROR_MARK.  */
4430
4431 void
4432 store_init_value (tree decl, tree init)
4433 {
4434   tree value, type;
4435
4436   /* If variable's type was invalidly declared, just ignore it.  */
4437
4438   type = TREE_TYPE (decl);
4439   if (TREE_CODE (type) == ERROR_MARK)
4440     return;
4441
4442   /* Digest the specified initializer into an expression.  */
4443
4444   value = digest_init (type, init, true, TREE_STATIC (decl));
4445
4446   /* Store the expression if valid; else report error.  */
4447
4448   if (!in_system_header
4449       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4450     warning (OPT_Wtraditional, "traditional C rejects automatic "
4451              "aggregate initialization");
4452
4453   DECL_INITIAL (decl) = value;
4454
4455   /* ANSI wants warnings about out-of-range constant initializers.  */
4456   STRIP_TYPE_NOPS (value);
4457   if (TREE_STATIC (decl))
4458     constant_expression_warning (value);
4459
4460   /* Check if we need to set array size from compound literal size.  */
4461   if (TREE_CODE (type) == ARRAY_TYPE
4462       && TYPE_DOMAIN (type) == 0
4463       && value != error_mark_node)
4464     {
4465       tree inside_init = init;
4466
4467       STRIP_TYPE_NOPS (inside_init);
4468       inside_init = fold (inside_init);
4469
4470       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4471         {
4472           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4473
4474           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4475             {
4476               /* For int foo[] = (int [3]){1}; we need to set array size
4477                  now since later on array initializer will be just the
4478                  brace enclosed list of the compound literal.  */
4479               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4480               TREE_TYPE (decl) = type;
4481               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4482               layout_type (type);
4483               layout_decl (cldecl, 0);
4484             }
4485         }
4486     }
4487 }
4488 \f
4489 /* Methods for storing and printing names for error messages.  */
4490
4491 /* Implement a spelling stack that allows components of a name to be pushed
4492    and popped.  Each element on the stack is this structure.  */
4493
4494 struct spelling
4495 {
4496   int kind;
4497   union
4498     {
4499       unsigned HOST_WIDE_INT i;
4500       const char *s;
4501     } u;
4502 };
4503
4504 #define SPELLING_STRING 1
4505 #define SPELLING_MEMBER 2
4506 #define SPELLING_BOUNDS 3
4507
4508 static struct spelling *spelling;       /* Next stack element (unused).  */
4509 static struct spelling *spelling_base;  /* Spelling stack base.  */
4510 static int spelling_size;               /* Size of the spelling stack.  */
4511
4512 /* Macros to save and restore the spelling stack around push_... functions.
4513    Alternative to SAVE_SPELLING_STACK.  */
4514
4515 #define SPELLING_DEPTH() (spelling - spelling_base)
4516 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4517
4518 /* Push an element on the spelling stack with type KIND and assign VALUE
4519    to MEMBER.  */
4520
4521 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4522 {                                                                       \
4523   int depth = SPELLING_DEPTH ();                                        \
4524                                                                         \
4525   if (depth >= spelling_size)                                           \
4526     {                                                                   \
4527       spelling_size += 10;                                              \
4528       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4529                                   spelling_size);                       \
4530       RESTORE_SPELLING_DEPTH (depth);                                   \
4531     }                                                                   \
4532                                                                         \
4533   spelling->kind = (KIND);                                              \
4534   spelling->MEMBER = (VALUE);                                           \
4535   spelling++;                                                           \
4536 }
4537
4538 /* Push STRING on the stack.  Printed literally.  */
4539
4540 static void
4541 push_string (const char *string)
4542 {
4543   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4544 }
4545
4546 /* Push a member name on the stack.  Printed as '.' STRING.  */
4547
4548 static void
4549 push_member_name (tree decl)
4550 {
4551   const char *const string
4552     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4553   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4554 }
4555
4556 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4557
4558 static void
4559 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4560 {
4561   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4562 }
4563
4564 /* Compute the maximum size in bytes of the printed spelling.  */
4565
4566 static int
4567 spelling_length (void)
4568 {
4569   int size = 0;
4570   struct spelling *p;
4571
4572   for (p = spelling_base; p < spelling; p++)
4573     {
4574       if (p->kind == SPELLING_BOUNDS)
4575         size += 25;
4576       else
4577         size += strlen (p->u.s) + 1;
4578     }
4579
4580   return size;
4581 }
4582
4583 /* Print the spelling to BUFFER and return it.  */
4584
4585 static char *
4586 print_spelling (char *buffer)
4587 {
4588   char *d = buffer;
4589   struct spelling *p;
4590
4591   for (p = spelling_base; p < spelling; p++)
4592     if (p->kind == SPELLING_BOUNDS)
4593       {
4594         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4595         d += strlen (d);
4596       }
4597     else
4598       {
4599         const char *s;
4600         if (p->kind == SPELLING_MEMBER)
4601           *d++ = '.';
4602         for (s = p->u.s; (*d = *s++); d++)
4603           ;
4604       }
4605   *d++ = '\0';
4606   return buffer;
4607 }
4608
4609 /* Issue an error message for a bad initializer component.
4610    MSGID identifies the message.
4611    The component name is taken from the spelling stack.  */
4612
4613 void
4614 error_init (const char *msgid)
4615 {
4616   char *ofwhat;
4617
4618   error ("%s", _(msgid));
4619   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4620   if (*ofwhat)
4621     error ("(near initialization for %qs)", ofwhat);
4622 }
4623
4624 /* Issue a pedantic warning for a bad initializer component.
4625    MSGID identifies the message.
4626    The component name is taken from the spelling stack.  */
4627
4628 void
4629 pedwarn_init (const char *msgid)
4630 {
4631   char *ofwhat;
4632
4633   pedwarn ("%s", _(msgid));
4634   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4635   if (*ofwhat)
4636     pedwarn ("(near initialization for %qs)", ofwhat);
4637 }
4638
4639 /* Issue a warning for a bad initializer component.
4640
4641    OPT is the OPT_W* value corresponding to the warning option that
4642    controls this warning.  MSGID identifies the message.  The
4643    component name is taken from the spelling stack.  */
4644
4645 static void
4646 warning_init (int opt, const char *msgid)
4647 {
4648   char *ofwhat;
4649
4650   warning (opt, "%s", _(msgid));
4651   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4652   if (*ofwhat)
4653     warning (opt, "(near initialization for %qs)", ofwhat);
4654 }
4655 \f
4656 /* If TYPE is an array type and EXPR is a parenthesized string
4657    constant, warn if pedantic that EXPR is being used to initialize an
4658    object of type TYPE.  */
4659
4660 void
4661 maybe_warn_string_init (tree type, struct c_expr expr)
4662 {
4663   if (pedantic
4664       && TREE_CODE (type) == ARRAY_TYPE
4665       && TREE_CODE (expr.value) == STRING_CST
4666       && expr.original_code != STRING_CST)
4667     pedwarn_init ("array initialized from parenthesized string constant");
4668 }
4669
4670 /* Digest the parser output INIT as an initializer for type TYPE.
4671    Return a C expression of type TYPE to represent the initial value.
4672
4673    If INIT is a string constant, STRICT_STRING is true if it is
4674    unparenthesized or we should not warn here for it being parenthesized.
4675    For other types of INIT, STRICT_STRING is not used.
4676
4677    REQUIRE_CONSTANT requests an error if non-constant initializers or
4678    elements are seen.  */
4679
4680 static tree
4681 digest_init (tree type, tree init, bool strict_string, int require_constant)
4682 {
4683   enum tree_code code = TREE_CODE (type);
4684   tree inside_init = init;
4685
4686   if (type == error_mark_node
4687       || !init
4688       || init == error_mark_node
4689       || TREE_TYPE (init) == error_mark_node)
4690     return error_mark_node;
4691
4692   STRIP_TYPE_NOPS (inside_init);
4693
4694   inside_init = fold (inside_init);
4695
4696   /* Initialization of an array of chars from a string constant
4697      optionally enclosed in braces.  */
4698
4699   if (code == ARRAY_TYPE && inside_init
4700       && TREE_CODE (inside_init) == STRING_CST)
4701     {
4702       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4703       /* Note that an array could be both an array of character type
4704          and an array of wchar_t if wchar_t is signed char or unsigned
4705          char.  */
4706       bool char_array = (typ1 == char_type_node
4707                          || typ1 == signed_char_type_node
4708                          || typ1 == unsigned_char_type_node);
4709       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4710       if (char_array || wchar_array)
4711         {
4712           struct c_expr expr;
4713           bool char_string;
4714           expr.value = inside_init;
4715           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4716           maybe_warn_string_init (type, expr);
4717
4718           char_string
4719             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4720                == char_type_node);
4721
4722           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4723                          TYPE_MAIN_VARIANT (type)))
4724             return inside_init;
4725
4726           if (!wchar_array && !char_string)
4727             {
4728               error_init ("char-array initialized from wide string");
4729               return error_mark_node;
4730             }
4731           if (char_string && !char_array)
4732             {
4733               error_init ("wchar_t-array initialized from non-wide string");
4734               return error_mark_node;
4735             }
4736
4737           TREE_TYPE (inside_init) = type;
4738           if (TYPE_DOMAIN (type) != 0
4739               && TYPE_SIZE (type) != 0
4740               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4741               /* Subtract 1 (or sizeof (wchar_t))
4742                  because it's ok to ignore the terminating null char
4743                  that is counted in the length of the constant.  */
4744               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4745                                        TREE_STRING_LENGTH (inside_init)
4746                                        - ((TYPE_PRECISION (typ1)
4747                                            != TYPE_PRECISION (char_type_node))
4748                                           ? (TYPE_PRECISION (wchar_type_node)
4749                                              / BITS_PER_UNIT)
4750                                           : 1)))
4751             pedwarn_init ("initializer-string for array of chars is too long");
4752
4753           return inside_init;
4754         }
4755       else if (INTEGRAL_TYPE_P (typ1))
4756         {
4757           error_init ("array of inappropriate type initialized "
4758                       "from string constant");
4759           return error_mark_node;
4760         }
4761     }
4762
4763   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4764      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4765      below and handle as a constructor.  */
4766   if (code == VECTOR_TYPE
4767       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4768       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4769       && TREE_CONSTANT (inside_init))
4770     {
4771       if (TREE_CODE (inside_init) == VECTOR_CST
4772           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4773                         TYPE_MAIN_VARIANT (type)))
4774         return inside_init;
4775
4776       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4777         {
4778           unsigned HOST_WIDE_INT ix;
4779           tree value;
4780           bool constant_p = true;
4781
4782           /* Iterate through elements and check if all constructor
4783              elements are *_CSTs.  */
4784           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4785             if (!CONSTANT_CLASS_P (value))
4786               {
4787                 constant_p = false;
4788                 break;
4789               }
4790
4791           if (constant_p)
4792             return build_vector_from_ctor (type,
4793                                            CONSTRUCTOR_ELTS (inside_init));
4794         }
4795     }
4796
4797   /* Any type can be initialized
4798      from an expression of the same type, optionally with braces.  */
4799
4800   if (inside_init && TREE_TYPE (inside_init) != 0
4801       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4802                      TYPE_MAIN_VARIANT (type))
4803           || (code == ARRAY_TYPE
4804               && comptypes (TREE_TYPE (inside_init), type))
4805           || (code == VECTOR_TYPE
4806               && comptypes (TREE_TYPE (inside_init), type))
4807           || (code == POINTER_TYPE
4808               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4809               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4810                             TREE_TYPE (type)))))
4811     {
4812       if (code == POINTER_TYPE)
4813         {
4814           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4815             {
4816               if (TREE_CODE (inside_init) == STRING_CST
4817                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4818                 inside_init = array_to_pointer_conversion (inside_init);
4819               else
4820                 {
4821                   error_init ("invalid use of non-lvalue array");
4822                   return error_mark_node;
4823                 }
4824             }
4825         }
4826
4827       if (code == VECTOR_TYPE)
4828         /* Although the types are compatible, we may require a
4829            conversion.  */
4830         inside_init = convert (type, inside_init);
4831
4832       if (require_constant
4833           && (code == VECTOR_TYPE || !flag_isoc99)
4834           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4835         {
4836           /* As an extension, allow initializing objects with static storage
4837              duration with compound literals (which are then treated just as
4838              the brace enclosed list they contain).  Also allow this for
4839              vectors, as we can only assign them with compound literals.  */
4840           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4841           inside_init = DECL_INITIAL (decl);
4842         }
4843
4844       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4845           && TREE_CODE (inside_init) != CONSTRUCTOR)
4846         {
4847           error_init ("array initialized from non-constant array expression");
4848           return error_mark_node;
4849         }
4850
4851       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4852         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4853
4854       /* Compound expressions can only occur here if -pedantic or
4855          -pedantic-errors is specified.  In the later case, we always want
4856          an error.  In the former case, we simply want a warning.  */
4857       if (require_constant && pedantic
4858           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4859         {
4860           inside_init
4861             = valid_compound_expr_initializer (inside_init,
4862                                                TREE_TYPE (inside_init));
4863           if (inside_init == error_mark_node)
4864             error_init ("initializer element is not constant");
4865           else
4866             pedwarn_init ("initializer element is not constant");
4867           if (flag_pedantic_errors)
4868             inside_init = error_mark_node;
4869         }
4870       else if (require_constant
4871                && !initializer_constant_valid_p (inside_init,
4872                                                  TREE_TYPE (inside_init)))
4873         {
4874           error_init ("initializer element is not constant");
4875           inside_init = error_mark_node;
4876         }
4877
4878       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4879       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4880         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4881                                               NULL_TREE, 0);
4882       return inside_init;
4883     }
4884
4885   /* Handle scalar types, including conversions.  */
4886
4887   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4888       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4889       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4890     {
4891       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4892           && (TREE_CODE (init) == STRING_CST
4893               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4894         init = array_to_pointer_conversion (init);
4895       inside_init
4896         = convert_for_assignment (type, init, ic_init,
4897                                   NULL_TREE, NULL_TREE, 0);
4898
4899       /* Check to see if we have already given an error message.  */
4900       if (inside_init == error_mark_node)
4901         ;
4902       else if (require_constant && !TREE_CONSTANT (inside_init))
4903         {
4904           error_init ("initializer element is not constant");
4905           inside_init = error_mark_node;
4906         }
4907       else if (require_constant
4908                && !initializer_constant_valid_p (inside_init,
4909                                                  TREE_TYPE (inside_init)))
4910         {
4911           error_init ("initializer element is not computable at load time");
4912           inside_init = error_mark_node;
4913         }
4914
4915       return inside_init;
4916     }
4917
4918   /* Come here only for records and arrays.  */
4919
4920   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4921     {
4922       error_init ("variable-sized object may not be initialized");
4923       return error_mark_node;
4924     }
4925
4926   error_init ("invalid initializer");
4927   return error_mark_node;
4928 }
4929 \f
4930 /* Handle initializers that use braces.  */
4931
4932 /* Type of object we are accumulating a constructor for.
4933    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4934 static tree constructor_type;
4935
4936 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4937    left to fill.  */
4938 static tree constructor_fields;
4939
4940 /* For an ARRAY_TYPE, this is the specified index
4941    at which to store the next element we get.  */
4942 static tree constructor_index;
4943
4944 /* For an ARRAY_TYPE, this is the maximum index.  */
4945 static tree constructor_max_index;
4946
4947 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4948 static tree constructor_unfilled_fields;
4949
4950 /* For an ARRAY_TYPE, this is the index of the first element
4951    not yet written out.  */
4952 static tree constructor_unfilled_index;
4953
4954 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4955    This is so we can generate gaps between fields, when appropriate.  */
4956 static tree constructor_bit_index;
4957
4958 /* If we are saving up the elements rather than allocating them,
4959    this is the list of elements so far (in reverse order,
4960    most recent first).  */
4961 static VEC(constructor_elt,gc) *constructor_elements;
4962
4963 /* 1 if constructor should be incrementally stored into a constructor chain,
4964    0 if all the elements should be kept in AVL tree.  */
4965 static int constructor_incremental;
4966
4967 /* 1 if so far this constructor's elements are all compile-time constants.  */
4968 static int constructor_constant;
4969
4970 /* 1 if so far this constructor's elements are all valid address constants.  */
4971 static int constructor_simple;
4972
4973 /* 1 if this constructor is erroneous so far.  */
4974 static int constructor_erroneous;
4975
4976 /* Structure for managing pending initializer elements, organized as an
4977    AVL tree.  */
4978
4979 struct init_node
4980 {
4981   struct init_node *left, *right;
4982   struct init_node *parent;
4983   int balance;
4984   tree purpose;
4985   tree value;
4986 };
4987
4988 /* Tree of pending elements at this constructor level.
4989    These are elements encountered out of order
4990    which belong at places we haven't reached yet in actually
4991    writing the output.
4992    Will never hold tree nodes across GC runs.  */
4993 static struct init_node *constructor_pending_elts;
4994
4995 /* The SPELLING_DEPTH of this constructor.  */
4996 static int constructor_depth;
4997
4998 /* DECL node for which an initializer is being read.
4999    0 means we are reading a constructor expression
5000    such as (struct foo) {...}.  */
5001 static tree constructor_decl;
5002
5003 /* Nonzero if this is an initializer for a top-level decl.  */
5004 static int constructor_top_level;
5005
5006 /* Nonzero if there were any member designators in this initializer.  */
5007 static int constructor_designated;
5008
5009 /* Nesting depth of designator list.  */
5010 static int designator_depth;
5011
5012 /* Nonzero if there were diagnosed errors in this designator list.  */
5013 static int designator_erroneous;
5014
5015 \f
5016 /* This stack has a level for each implicit or explicit level of
5017    structuring in the initializer, including the outermost one.  It
5018    saves the values of most of the variables above.  */
5019
5020 struct constructor_range_stack;
5021
5022 struct constructor_stack
5023 {
5024   struct constructor_stack *next;
5025   tree type;
5026   tree fields;
5027   tree index;
5028   tree max_index;
5029   tree unfilled_index;
5030   tree unfilled_fields;
5031   tree bit_index;
5032   VEC(constructor_elt,gc) *elements;
5033   struct init_node *pending_elts;
5034   int offset;
5035   int depth;
5036   /* If value nonzero, this value should replace the entire
5037      constructor at this level.  */
5038   struct c_expr replacement_value;
5039   struct constructor_range_stack *range_stack;
5040   char constant;
5041   char simple;
5042   char implicit;
5043   char erroneous;
5044   char outer;
5045   char incremental;
5046   char designated;
5047 };
5048
5049 static struct constructor_stack *constructor_stack;
5050
5051 /* This stack represents designators from some range designator up to
5052    the last designator in the list.  */
5053
5054 struct constructor_range_stack
5055 {
5056   struct constructor_range_stack *next, *prev;
5057   struct constructor_stack *stack;
5058   tree range_start;
5059   tree index;
5060   tree range_end;
5061   tree fields;
5062 };
5063
5064 static struct constructor_range_stack *constructor_range_stack;
5065
5066 /* This stack records separate initializers that are nested.
5067    Nested initializers can't happen in ANSI C, but GNU C allows them
5068    in cases like { ... (struct foo) { ... } ... }.  */
5069
5070 struct initializer_stack
5071 {
5072   struct initializer_stack *next;
5073   tree decl;
5074   struct constructor_stack *constructor_stack;
5075   struct constructor_range_stack *constructor_range_stack;
5076   VEC(constructor_elt,gc) *elements;
5077   struct spelling *spelling;
5078   struct spelling *spelling_base;
5079   int spelling_size;
5080   char top_level;
5081   char require_constant_value;
5082   char require_constant_elements;
5083 };
5084
5085 static struct initializer_stack *initializer_stack;
5086 \f
5087 /* Prepare to parse and output the initializer for variable DECL.  */
5088
5089 void
5090 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5091 {
5092   const char *locus;
5093   struct initializer_stack *p = XNEW (struct initializer_stack);
5094
5095   p->decl = constructor_decl;
5096   p->require_constant_value = require_constant_value;
5097   p->require_constant_elements = require_constant_elements;
5098   p->constructor_stack = constructor_stack;
5099   p->constructor_range_stack = constructor_range_stack;
5100   p->elements = constructor_elements;
5101   p->spelling = spelling;
5102   p->spelling_base = spelling_base;
5103   p->spelling_size = spelling_size;
5104   p->top_level = constructor_top_level;
5105   p->next = initializer_stack;
5106   initializer_stack = p;
5107
5108   constructor_decl = decl;
5109   constructor_designated = 0;
5110   constructor_top_level = top_level;
5111
5112   if (decl != 0 && decl != error_mark_node)
5113     {
5114       require_constant_value = TREE_STATIC (decl);
5115       require_constant_elements
5116         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5117            /* For a scalar, you can always use any value to initialize,
5118               even within braces.  */
5119            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5120                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5121                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5122                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5123       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5124     }
5125   else
5126     {
5127       require_constant_value = 0;
5128       require_constant_elements = 0;
5129       locus = "(anonymous)";
5130     }
5131
5132   constructor_stack = 0;
5133   constructor_range_stack = 0;
5134
5135   missing_braces_mentioned = 0;
5136
5137   spelling_base = 0;
5138   spelling_size = 0;
5139   RESTORE_SPELLING_DEPTH (0);
5140
5141   if (locus)
5142     push_string (locus);
5143 }
5144
5145 void
5146 finish_init (void)
5147 {
5148   struct initializer_stack *p = initializer_stack;
5149
5150   /* Free the whole constructor stack of this initializer.  */
5151   while (constructor_stack)
5152     {
5153       struct constructor_stack *q = constructor_stack;
5154       constructor_stack = q->next;
5155       free (q);
5156     }
5157
5158   gcc_assert (!constructor_range_stack);
5159
5160   /* Pop back to the data of the outer initializer (if any).  */
5161   free (spelling_base);
5162
5163   constructor_decl = p->decl;
5164   require_constant_value = p->require_constant_value;
5165   require_constant_elements = p->require_constant_elements;
5166   constructor_stack = p->constructor_stack;
5167   constructor_range_stack = p->constructor_range_stack;
5168   constructor_elements = p->elements;
5169   spelling = p->spelling;
5170   spelling_base = p->spelling_base;
5171   spelling_size = p->spelling_size;
5172   constructor_top_level = p->top_level;
5173   initializer_stack = p->next;
5174   free (p);
5175 }
5176 \f
5177 /* Call here when we see the initializer is surrounded by braces.
5178    This is instead of a call to push_init_level;
5179    it is matched by a call to pop_init_level.
5180
5181    TYPE is the type to initialize, for a constructor expression.
5182    For an initializer for a decl, TYPE is zero.  */
5183
5184 void
5185 really_start_incremental_init (tree type)
5186 {
5187   struct constructor_stack *p = XNEW (struct constructor_stack);
5188
5189   if (type == 0)
5190     type = TREE_TYPE (constructor_decl);
5191
5192   if (targetm.vector_opaque_p (type))
5193     error ("opaque vector types cannot be initialized");
5194
5195   p->type = constructor_type;
5196   p->fields = constructor_fields;
5197   p->index = constructor_index;
5198   p->max_index = constructor_max_index;
5199   p->unfilled_index = constructor_unfilled_index;
5200   p->unfilled_fields = constructor_unfilled_fields;
5201   p->bit_index = constructor_bit_index;
5202   p->elements = constructor_elements;
5203   p->constant = constructor_constant;
5204   p->simple = constructor_simple;
5205   p->erroneous = constructor_erroneous;
5206   p->pending_elts = constructor_pending_elts;
5207   p->depth = constructor_depth;
5208   p->replacement_value.value = 0;
5209   p->replacement_value.original_code = ERROR_MARK;
5210   p->implicit = 0;
5211   p->range_stack = 0;
5212   p->outer = 0;
5213   p->incremental = constructor_incremental;
5214   p->designated = constructor_designated;
5215   p->next = 0;
5216   constructor_stack = p;
5217
5218   constructor_constant = 1;
5219   constructor_simple = 1;
5220   constructor_depth = SPELLING_DEPTH ();
5221   constructor_elements = 0;
5222   constructor_pending_elts = 0;
5223   constructor_type = type;
5224   constructor_incremental = 1;
5225   constructor_designated = 0;
5226   designator_depth = 0;
5227   designator_erroneous = 0;
5228
5229   if (TREE_CODE (constructor_type) == RECORD_TYPE
5230       || TREE_CODE (constructor_type) == UNION_TYPE)
5231     {
5232       constructor_fields = TYPE_FIELDS (constructor_type);
5233       /* Skip any nameless bit fields at the beginning.  */
5234       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5235              && DECL_NAME (constructor_fields) == 0)
5236         constructor_fields = TREE_CHAIN (constructor_fields);
5237
5238       constructor_unfilled_fields = constructor_fields;
5239       constructor_bit_index = bitsize_zero_node;
5240     }
5241   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5242     {
5243       if (TYPE_DOMAIN (constructor_type))
5244         {
5245           constructor_max_index
5246             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5247
5248           /* Detect non-empty initializations of zero-length arrays.  */
5249           if (constructor_max_index == NULL_TREE
5250               && TYPE_SIZE (constructor_type))
5251             constructor_max_index = build_int_cst (NULL_TREE, -1);
5252
5253           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5254              to initialize VLAs will cause a proper error; avoid tree
5255              checking errors as well by setting a safe value.  */
5256           if (constructor_max_index
5257               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5258             constructor_max_index = build_int_cst (NULL_TREE, -1);
5259
5260           constructor_index
5261             = convert (bitsizetype,
5262                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5263         }
5264       else
5265         {
5266           constructor_index = bitsize_zero_node;
5267           constructor_max_index = NULL_TREE;
5268         }
5269
5270       constructor_unfilled_index = constructor_index;
5271     }
5272   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5273     {
5274       /* Vectors are like simple fixed-size arrays.  */
5275       constructor_max_index =
5276         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5277       constructor_index = bitsize_zero_node;
5278       constructor_unfilled_index = constructor_index;
5279     }
5280   else
5281     {
5282       /* Handle the case of int x = {5}; */
5283       constructor_fields = constructor_type;
5284       constructor_unfilled_fields = constructor_type;
5285     }
5286 }
5287 \f
5288 /* Push down into a subobject, for initialization.
5289    If this is for an explicit set of braces, IMPLICIT is 0.
5290    If it is because the next element belongs at a lower level,
5291    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5292
5293 void
5294 push_init_level (int implicit)
5295 {
5296   struct constructor_stack *p;
5297   tree value = NULL_TREE;
5298
5299   /* If we've exhausted any levels that didn't have braces,
5300      pop them now.  If implicit == 1, this will have been done in
5301      process_init_element; do not repeat it here because in the case
5302      of excess initializers for an empty aggregate this leads to an
5303      infinite cycle of popping a level and immediately recreating
5304      it.  */
5305   if (implicit != 1)
5306     {
5307       while (constructor_stack->implicit)
5308         {
5309           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5310                || TREE_CODE (constructor_type) == UNION_TYPE)
5311               && constructor_fields == 0)
5312             process_init_element (pop_init_level (1));
5313           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5314                    && constructor_max_index
5315                    && tree_int_cst_lt (constructor_max_index,
5316                                        constructor_index))
5317             process_init_element (pop_init_level (1));
5318           else
5319             break;
5320         }
5321     }
5322
5323   /* Unless this is an explicit brace, we need to preserve previous
5324      content if any.  */
5325   if (implicit)
5326     {
5327       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5328            || TREE_CODE (constructor_type) == UNION_TYPE)
5329           && constructor_fields)
5330         value = find_init_member (constructor_fields);
5331       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5332         value = find_init_member (constructor_index);
5333     }
5334
5335   p = XNEW (struct constructor_stack);
5336   p->type = constructor_type;
5337   p->fields = constructor_fields;
5338   p->index = constructor_index;
5339   p->max_index = constructor_max_index;
5340   p->unfilled_index = constructor_unfilled_index;
5341   p->unfilled_fields = constructor_unfilled_fields;
5342   p->bit_index = constructor_bit_index;
5343   p->elements = constructor_elements;
5344   p->constant = constructor_constant;
5345   p->simple = constructor_simple;
5346   p->erroneous = constructor_erroneous;
5347   p->pending_elts = constructor_pending_elts;
5348   p->depth = constructor_depth;
5349   p->replacement_value.value = 0;
5350   p->replacement_value.original_code = ERROR_MARK;
5351   p->implicit = implicit;
5352   p->outer = 0;
5353   p->incremental = constructor_incremental;
5354   p->designated = constructor_designated;
5355   p->next = constructor_stack;
5356   p->range_stack = 0;
5357   constructor_stack = p;
5358
5359   constructor_constant = 1;
5360   constructor_simple = 1;
5361   constructor_depth = SPELLING_DEPTH ();
5362   constructor_elements = 0;
5363   constructor_incremental = 1;
5364   constructor_designated = 0;
5365   constructor_pending_elts = 0;
5366   if (!implicit)
5367     {
5368       p->range_stack = constructor_range_stack;
5369       constructor_range_stack = 0;
5370       designator_depth = 0;
5371       designator_erroneous = 0;
5372     }
5373
5374   /* Don't die if an entire brace-pair level is superfluous
5375      in the containing level.  */
5376   if (constructor_type == 0)
5377     ;
5378   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5379            || TREE_CODE (constructor_type) == UNION_TYPE)
5380     {
5381       /* Don't die if there are extra init elts at the end.  */
5382       if (constructor_fields == 0)
5383         constructor_type = 0;
5384       else
5385         {
5386           constructor_type = TREE_TYPE (constructor_fields);
5387           push_member_name (constructor_fields);
5388           constructor_depth++;
5389         }
5390     }
5391   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5392     {
5393       constructor_type = TREE_TYPE (constructor_type);
5394       push_array_bounds (tree_low_cst (constructor_index, 1));
5395       constructor_depth++;
5396     }
5397
5398   if (constructor_type == 0)
5399     {
5400       error_init ("extra brace group at end of initializer");
5401       constructor_fields = 0;
5402       constructor_unfilled_fields = 0;
5403       return;
5404     }
5405
5406   if (value && TREE_CODE (value) == CONSTRUCTOR)
5407     {
5408       constructor_constant = TREE_CONSTANT (value);
5409       constructor_simple = TREE_STATIC (value);
5410       constructor_elements = CONSTRUCTOR_ELTS (value);
5411       if (!VEC_empty (constructor_elt, constructor_elements)
5412           && (TREE_CODE (constructor_type) == RECORD_TYPE
5413               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5414         set_nonincremental_init ();
5415     }
5416
5417   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5418     {
5419       missing_braces_mentioned = 1;
5420       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5421     }
5422
5423   if (TREE_CODE (constructor_type) == RECORD_TYPE
5424            || TREE_CODE (constructor_type) == UNION_TYPE)
5425     {
5426       constructor_fields = TYPE_FIELDS (constructor_type);
5427       /* Skip any nameless bit fields at the beginning.  */
5428       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5429              && DECL_NAME (constructor_fields) == 0)
5430         constructor_fields = TREE_CHAIN (constructor_fields);
5431
5432       constructor_unfilled_fields = constructor_fields;
5433       constructor_bit_index = bitsize_zero_node;
5434     }
5435   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5436     {
5437       /* Vectors are like simple fixed-size arrays.  */
5438       constructor_max_index =
5439         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5440       constructor_index = convert (bitsizetype, integer_zero_node);
5441       constructor_unfilled_index = constructor_index;
5442     }
5443   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5444     {
5445       if (TYPE_DOMAIN (constructor_type))
5446         {
5447           constructor_max_index
5448             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5449
5450           /* Detect non-empty initializations of zero-length arrays.  */
5451           if (constructor_max_index == NULL_TREE
5452               && TYPE_SIZE (constructor_type))
5453             constructor_max_index = build_int_cst (NULL_TREE, -1);
5454
5455           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5456              to initialize VLAs will cause a proper error; avoid tree
5457              checking errors as well by setting a safe value.  */
5458           if (constructor_max_index
5459               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5460             constructor_max_index = build_int_cst (NULL_TREE, -1);
5461
5462           constructor_index
5463             = convert (bitsizetype,
5464                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5465         }
5466       else
5467         constructor_index = bitsize_zero_node;
5468
5469       constructor_unfilled_index = constructor_index;
5470       if (value && TREE_CODE (value) == STRING_CST)
5471         {
5472           /* We need to split the char/wchar array into individual
5473              characters, so that we don't have to special case it
5474              everywhere.  */
5475           set_nonincremental_init_from_string (value);
5476         }
5477     }
5478   else
5479     {
5480       if (constructor_type != error_mark_node)
5481         warning_init (0, "braces around scalar initializer");
5482       constructor_fields = constructor_type;
5483       constructor_unfilled_fields = constructor_type;
5484     }
5485 }
5486
5487 /* At the end of an implicit or explicit brace level,
5488    finish up that level of constructor.  If a single expression
5489    with redundant braces initialized that level, return the
5490    c_expr structure for that expression.  Otherwise, the original_code
5491    element is set to ERROR_MARK.
5492    If we were outputting the elements as they are read, return 0 as the value
5493    from inner levels (process_init_element ignores that),
5494    but return error_mark_node as the value from the outermost level
5495    (that's what we want to put in DECL_INITIAL).
5496    Otherwise, return a CONSTRUCTOR expression as the value.  */
5497
5498 struct c_expr
5499 pop_init_level (int implicit)
5500 {
5501   struct constructor_stack *p;
5502   struct c_expr ret;
5503   ret.value = 0;
5504   ret.original_code = ERROR_MARK;
5505
5506   if (implicit == 0)
5507     {
5508       /* When we come to an explicit close brace,
5509          pop any inner levels that didn't have explicit braces.  */
5510       while (constructor_stack->implicit)
5511         process_init_element (pop_init_level (1));
5512
5513       gcc_assert (!constructor_range_stack);
5514     }
5515
5516   /* Now output all pending elements.  */
5517   constructor_incremental = 1;
5518   output_pending_init_elements (1);
5519
5520   p = constructor_stack;
5521
5522   /* Error for initializing a flexible array member, or a zero-length
5523      array member in an inappropriate context.  */
5524   if (constructor_type && constructor_fields
5525       && TREE_CODE (constructor_type) == ARRAY_TYPE
5526       && TYPE_DOMAIN (constructor_type)
5527       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5528     {
5529       /* Silently discard empty initializations.  The parser will
5530          already have pedwarned for empty brackets.  */
5531       if (integer_zerop (constructor_unfilled_index))
5532         constructor_type = NULL_TREE;
5533       else
5534         {
5535           gcc_assert (!TYPE_SIZE (constructor_type));
5536
5537           if (constructor_depth > 2)
5538             error_init ("initialization of flexible array member in a nested context");
5539           else if (pedantic)
5540             pedwarn_init ("initialization of a flexible array member");
5541
5542           /* We have already issued an error message for the existence
5543              of a flexible array member not at the end of the structure.
5544              Discard the initializer so that we do not die later.  */
5545           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5546             constructor_type = NULL_TREE;
5547         }
5548     }
5549
5550   /* Warn when some struct elements are implicitly initialized to zero.  */
5551   if (warn_missing_field_initializers
5552       && constructor_type
5553       && TREE_CODE (constructor_type) == RECORD_TYPE
5554       && constructor_unfilled_fields)
5555     {
5556         /* Do not warn for flexible array members or zero-length arrays.  */
5557         while (constructor_unfilled_fields
5558                && (!DECL_SIZE (constructor_unfilled_fields)
5559                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5560           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5561
5562         /* Do not warn if this level of the initializer uses member
5563            designators; it is likely to be deliberate.  */
5564         if (constructor_unfilled_fields && !constructor_designated)
5565           {
5566             push_member_name (constructor_unfilled_fields);
5567             warning_init (OPT_Wmissing_field_initializers,
5568                           "missing initializer");
5569             RESTORE_SPELLING_DEPTH (constructor_depth);
5570           }
5571     }
5572
5573   /* Pad out the end of the structure.  */
5574   if (p->replacement_value.value)
5575     /* If this closes a superfluous brace pair,
5576        just pass out the element between them.  */
5577     ret = p->replacement_value;
5578   else if (constructor_type == 0)
5579     ;
5580   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5581            && TREE_CODE (constructor_type) != UNION_TYPE
5582            && TREE_CODE (constructor_type) != ARRAY_TYPE
5583            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5584     {
5585       /* A nonincremental scalar initializer--just return
5586          the element, after verifying there is just one.  */
5587       if (VEC_empty (constructor_elt,constructor_elements))
5588         {
5589           if (!constructor_erroneous)
5590             error_init ("empty scalar initializer");
5591           ret.value = error_mark_node;
5592         }
5593       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5594         {
5595           error_init ("extra elements in scalar initializer");
5596           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5597         }
5598       else
5599         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5600     }
5601   else
5602     {
5603       if (constructor_erroneous)
5604         ret.value = error_mark_node;
5605       else
5606         {
5607           ret.value = build_constructor (constructor_type,
5608                                          constructor_elements);
5609           if (constructor_constant)
5610             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5611           if (constructor_constant && constructor_simple)
5612             TREE_STATIC (ret.value) = 1;
5613         }
5614     }
5615
5616   constructor_type = p->type;
5617   constructor_fields = p->fields;
5618   constructor_index = p->index;
5619   constructor_max_index = p->max_index;
5620   constructor_unfilled_index = p->unfilled_index;
5621   constructor_unfilled_fields = p->unfilled_fields;
5622   constructor_bit_index = p->bit_index;
5623   constructor_elements = p->elements;
5624   constructor_constant = p->constant;
5625   constructor_simple = p->simple;
5626   constructor_erroneous = p->erroneous;
5627   constructor_incremental = p->incremental;
5628   constructor_designated = p->designated;
5629   constructor_pending_elts = p->pending_elts;
5630   constructor_depth = p->depth;
5631   if (!p->implicit)
5632     constructor_range_stack = p->range_stack;
5633   RESTORE_SPELLING_DEPTH (constructor_depth);
5634
5635   constructor_stack = p->next;
5636   free (p);
5637
5638   if (ret.value == 0 && constructor_stack == 0)
5639     ret.value = error_mark_node;
5640   return ret;
5641 }
5642
5643 /* Common handling for both array range and field name designators.
5644    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5645
5646 static int
5647 set_designator (int array)
5648 {
5649   tree subtype;
5650   enum tree_code subcode;
5651
5652   /* Don't die if an entire brace-pair level is superfluous
5653      in the containing level.  */
5654   if (constructor_type == 0)
5655     return 1;
5656
5657   /* If there were errors in this designator list already, bail out
5658      silently.  */
5659   if (designator_erroneous)
5660     return 1;
5661
5662   if (!designator_depth)
5663     {
5664       gcc_assert (!constructor_range_stack);
5665
5666       /* Designator list starts at the level of closest explicit
5667          braces.  */
5668       while (constructor_stack->implicit)
5669         process_init_element (pop_init_level (1));
5670       constructor_designated = 1;
5671       return 0;
5672     }
5673
5674   switch (TREE_CODE (constructor_type))
5675     {
5676     case  RECORD_TYPE:
5677     case  UNION_TYPE:
5678       subtype = TREE_TYPE (constructor_fields);
5679       if (subtype != error_mark_node)
5680         subtype = TYPE_MAIN_VARIANT (subtype);
5681       break;
5682     case ARRAY_TYPE:
5683       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5684       break;
5685     default:
5686       gcc_unreachable ();
5687     }
5688
5689   subcode = TREE_CODE (subtype);
5690   if (array && subcode != ARRAY_TYPE)
5691     {
5692       error_init ("array index in non-array initializer");
5693       return 1;
5694     }
5695   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5696     {
5697       error_init ("field name not in record or union initializer");
5698       return 1;
5699     }
5700
5701   constructor_designated = 1;
5702   push_init_level (2);
5703   return 0;
5704 }
5705
5706 /* If there are range designators in designator list, push a new designator
5707    to constructor_range_stack.  RANGE_END is end of such stack range or
5708    NULL_TREE if there is no range designator at this level.  */
5709
5710 static void
5711 push_range_stack (tree range_end)
5712 {
5713   struct constructor_range_stack *p;
5714
5715   p = GGC_NEW (struct constructor_range_stack);
5716   p->prev = constructor_range_stack;
5717   p->next = 0;
5718   p->fields = constructor_fields;
5719   p->range_start = constructor_index;
5720   p->index = constructor_index;
5721   p->stack = constructor_stack;
5722   p->range_end = range_end;
5723   if (constructor_range_stack)
5724     constructor_range_stack->next = p;
5725   constructor_range_stack = p;
5726 }
5727
5728 /* Within an array initializer, specify the next index to be initialized.
5729    FIRST is that index.  If LAST is nonzero, then initialize a range
5730    of indices, running from FIRST through LAST.  */
5731
5732 void
5733 set_init_index (tree first, tree last)
5734 {
5735   if (set_designator (1))
5736     return;
5737
5738   designator_erroneous = 1;
5739
5740   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5741       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5742     {
5743       error_init ("array index in initializer not of integer type");
5744       return;
5745     }
5746
5747   if (TREE_CODE (first) != INTEGER_CST)
5748     error_init ("nonconstant array index in initializer");
5749   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5750     error_init ("nonconstant array index in initializer");
5751   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5752     error_init ("array index in non-array initializer");
5753   else if (tree_int_cst_sgn (first) == -1)
5754     error_init ("array index in initializer exceeds array bounds");
5755   else if (constructor_max_index
5756            && tree_int_cst_lt (constructor_max_index, first))
5757     error_init ("array index in initializer exceeds array bounds");
5758   else
5759     {
5760       constructor_index = convert (bitsizetype, first);
5761
5762       if (last)
5763         {
5764           if (tree_int_cst_equal (first, last))
5765             last = 0;
5766           else if (tree_int_cst_lt (last, first))
5767             {
5768               error_init ("empty index range in initializer");
5769               last = 0;
5770             }
5771           else
5772             {
5773               last = convert (bitsizetype, last);
5774               if (constructor_max_index != 0
5775                   && tree_int_cst_lt (constructor_max_index, last))
5776                 {
5777                   error_init ("array index range in initializer exceeds array bounds");
5778                   last = 0;
5779                 }
5780             }
5781         }
5782
5783       designator_depth++;
5784       designator_erroneous = 0;
5785       if (constructor_range_stack || last)
5786         push_range_stack (last);
5787     }
5788 }
5789
5790 /* Within a struct initializer, specify the next field to be initialized.  */
5791
5792 void
5793 set_init_label (tree fieldname)
5794 {
5795   tree tail;
5796
5797   if (set_designator (0))
5798     return;
5799
5800   designator_erroneous = 1;
5801
5802   if (TREE_CODE (constructor_type) != RECORD_TYPE
5803       && TREE_CODE (constructor_type) != UNION_TYPE)
5804     {
5805       error_init ("field name not in record or union initializer");
5806       return;
5807     }
5808
5809   for (tail = TYPE_FIELDS (constructor_type); tail;
5810        tail = TREE_CHAIN (tail))
5811     {
5812       if (DECL_NAME (tail) == fieldname)
5813         break;
5814     }
5815
5816   if (tail == 0)
5817     error ("unknown field %qE specified in initializer", fieldname);
5818   else
5819     {
5820       constructor_fields = tail;
5821       designator_depth++;
5822       designator_erroneous = 0;
5823       if (constructor_range_stack)
5824         push_range_stack (NULL_TREE);
5825     }
5826 }
5827 \f
5828 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5829    identifies the initializer, either array index or field in a structure.
5830    VALUE is the value of that index or field.  */
5831
5832 static void
5833 add_pending_init (tree purpose, tree value)
5834 {
5835   struct init_node *p, **q, *r;
5836
5837   q = &constructor_pending_elts;
5838   p = 0;
5839
5840   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5841     {
5842       while (*q != 0)
5843         {
5844           p = *q;
5845           if (tree_int_cst_lt (purpose, p->purpose))
5846             q = &p->left;
5847           else if (tree_int_cst_lt (p->purpose, purpose))
5848             q = &p->right;
5849           else
5850             {
5851               if (TREE_SIDE_EFFECTS (p->value))
5852                 warning_init (0, "initialized field with side-effects overwritten");
5853               else if (warn_override_init)
5854                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5855               p->value = value;
5856               return;
5857             }
5858         }
5859     }
5860   else
5861     {
5862       tree bitpos;
5863
5864       bitpos = bit_position (purpose);
5865       while (*q != NULL)
5866         {
5867           p = *q;
5868           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5869             q = &p->left;
5870           else if (p->purpose != purpose)
5871             q = &p->right;
5872           else
5873             {
5874               if (TREE_SIDE_EFFECTS (p->value))
5875                 warning_init (0, "initialized field with side-effects overwritten");
5876               else if (warn_override_init)
5877                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5878               p->value = value;
5879               return;
5880             }
5881         }
5882     }
5883
5884   r = GGC_NEW (struct init_node);
5885   r->purpose = purpose;
5886   r->value = value;
5887
5888   *q = r;
5889   r->parent = p;
5890   r->left = 0;
5891   r->right = 0;
5892   r->balance = 0;
5893
5894   while (p)
5895     {
5896       struct init_node *s;
5897
5898       if (r == p->left)
5899         {
5900           if (p->balance == 0)
5901             p->balance = -1;
5902           else if (p->balance < 0)
5903             {
5904               if (r->balance < 0)
5905                 {
5906                   /* L rotation.  */
5907                   p->left = r->right;
5908                   if (p->left)
5909                     p->left->parent = p;
5910                   r->right = p;
5911
5912                   p->balance = 0;
5913                   r->balance = 0;
5914
5915                   s = p->parent;
5916                   p->parent = r;
5917                   r->parent = s;
5918                   if (s)
5919                     {
5920                       if (s->left == p)
5921                         s->left = r;
5922                       else
5923                         s->right = r;
5924                     }
5925                   else
5926                     constructor_pending_elts = r;
5927                 }
5928               else
5929                 {
5930                   /* LR rotation.  */
5931                   struct init_node *t = r->right;
5932
5933                   r->right = t->left;
5934                   if (r->right)
5935                     r->right->parent = r;
5936                   t->left = r;
5937
5938                   p->left = t->right;
5939                   if (p->left)
5940                     p->left->parent = p;
5941                   t->right = p;
5942
5943                   p->balance = t->balance < 0;
5944                   r->balance = -(t->balance > 0);
5945                   t->balance = 0;
5946
5947                   s = p->parent;
5948                   p->parent = t;
5949                   r->parent = t;
5950                   t->parent = s;
5951                   if (s)
5952                     {
5953                       if (s->left == p)
5954                         s->left = t;
5955                       else
5956                         s->right = t;
5957                     }
5958                   else
5959                     constructor_pending_elts = t;
5960                 }
5961               break;
5962             }
5963           else
5964             {
5965               /* p->balance == +1; growth of left side balances the node.  */
5966               p->balance = 0;
5967               break;
5968             }
5969         }
5970       else /* r == p->right */
5971         {
5972           if (p->balance == 0)
5973             /* Growth propagation from right side.  */
5974             p->balance++;
5975           else if (p->balance > 0)
5976             {
5977               if (r->balance > 0)
5978                 {
5979                   /* R rotation.  */
5980                   p->right = r->left;
5981                   if (p->right)
5982                     p->right->parent = p;
5983                   r->left = p;
5984
5985                   p->balance = 0;
5986                   r->balance = 0;
5987
5988                   s = p->parent;
5989                   p->parent = r;
5990                   r->parent = s;
5991                   if (s)
5992                     {
5993                       if (s->left == p)
5994                         s->left = r;
5995                       else
5996                         s->right = r;
5997                     }
5998                   else
5999                     constructor_pending_elts = r;
6000                 }
6001               else /* r->balance == -1 */
6002                 {
6003                   /* RL rotation */
6004                   struct init_node *t = r->left;
6005
6006                   r->left = t->right;
6007                   if (r->left)
6008                     r->left->parent = r;
6009                   t->right = r;
6010
6011                   p->right = t->left;
6012                   if (p->right)
6013                     p->right->parent = p;
6014                   t->left = p;
6015
6016                   r->balance = (t->balance < 0);
6017                   p->balance = -(t->balance > 0);
6018                   t->balance = 0;
6019
6020                   s = p->parent;
6021                   p->parent = t;
6022                   r->parent = t;
6023                   t->parent = s;
6024                   if (s)
6025                     {
6026                       if (s->left == p)
6027                         s->left = t;
6028                       else
6029                         s->right = t;
6030                     }
6031                   else
6032                     constructor_pending_elts = t;
6033                 }
6034               break;
6035             }
6036           else
6037             {
6038               /* p->balance == -1; growth of right side balances the node.  */
6039               p->balance = 0;
6040               break;
6041             }
6042         }
6043
6044       r = p;
6045       p = p->parent;
6046     }
6047 }
6048
6049 /* Build AVL tree from a sorted chain.  */
6050
6051 static void
6052 set_nonincremental_init (void)
6053 {
6054   unsigned HOST_WIDE_INT ix;
6055   tree index, value;
6056
6057   if (TREE_CODE (constructor_type) != RECORD_TYPE
6058       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6059     return;
6060
6061   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6062     add_pending_init (index, value);
6063   constructor_elements = 0;
6064   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6065     {
6066       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6067       /* Skip any nameless bit fields at the beginning.  */
6068       while (constructor_unfilled_fields != 0
6069              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6070              && DECL_NAME (constructor_unfilled_fields) == 0)
6071         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6072
6073     }
6074   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6075     {
6076       if (TYPE_DOMAIN (constructor_type))
6077         constructor_unfilled_index
6078             = convert (bitsizetype,
6079                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6080       else
6081         constructor_unfilled_index = bitsize_zero_node;
6082     }
6083   constructor_incremental = 0;
6084 }
6085
6086 /* Build AVL tree from a string constant.  */
6087
6088 static void
6089 set_nonincremental_init_from_string (tree str)
6090 {
6091   tree value, purpose, type;
6092   HOST_WIDE_INT val[2];
6093   const char *p, *end;
6094   int byte, wchar_bytes, charwidth, bitpos;
6095
6096   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6097
6098   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6099       == TYPE_PRECISION (char_type_node))
6100     wchar_bytes = 1;
6101   else
6102     {
6103       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6104                   == TYPE_PRECISION (wchar_type_node));
6105       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6106     }
6107   charwidth = TYPE_PRECISION (char_type_node);
6108   type = TREE_TYPE (constructor_type);
6109   p = TREE_STRING_POINTER (str);
6110   end = p + TREE_STRING_LENGTH (str);
6111
6112   for (purpose = bitsize_zero_node;
6113        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6114        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6115     {
6116       if (wchar_bytes == 1)
6117         {
6118           val[1] = (unsigned char) *p++;
6119           val[0] = 0;
6120         }
6121       else
6122         {
6123           val[0] = 0;
6124           val[1] = 0;
6125           for (byte = 0; byte < wchar_bytes; byte++)
6126             {
6127               if (BYTES_BIG_ENDIAN)
6128                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6129               else
6130                 bitpos = byte * charwidth;
6131               val[bitpos < HOST_BITS_PER_WIDE_INT]
6132                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6133                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6134             }
6135         }
6136
6137       if (!TYPE_UNSIGNED (type))
6138         {
6139           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6140           if (bitpos < HOST_BITS_PER_WIDE_INT)
6141             {
6142               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6143                 {
6144                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6145                   val[0] = -1;
6146                 }
6147             }
6148           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6149             {
6150               if (val[1] < 0)
6151                 val[0] = -1;
6152             }
6153           else if (val[0] & (((HOST_WIDE_INT) 1)
6154                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6155             val[0] |= ((HOST_WIDE_INT) -1)
6156                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6157         }
6158
6159       value = build_int_cst_wide (type, val[1], val[0]);
6160       add_pending_init (purpose, value);
6161     }
6162
6163   constructor_incremental = 0;
6164 }
6165
6166 /* Return value of FIELD in pending initializer or zero if the field was
6167    not initialized yet.  */
6168
6169 static tree
6170 find_init_member (tree field)
6171 {
6172   struct init_node *p;
6173
6174   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6175     {
6176       if (constructor_incremental
6177           && tree_int_cst_lt (field, constructor_unfilled_index))
6178         set_nonincremental_init ();
6179
6180       p = constructor_pending_elts;
6181       while (p)
6182         {
6183           if (tree_int_cst_lt (field, p->purpose))
6184             p = p->left;
6185           else if (tree_int_cst_lt (p->purpose, field))
6186             p = p->right;
6187           else
6188             return p->value;
6189         }
6190     }
6191   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6192     {
6193       tree bitpos = bit_position (field);
6194
6195       if (constructor_incremental
6196           && (!constructor_unfilled_fields
6197               || tree_int_cst_lt (bitpos,
6198                                   bit_position (constructor_unfilled_fields))))
6199         set_nonincremental_init ();
6200
6201       p = constructor_pending_elts;
6202       while (p)
6203         {
6204           if (field == p->purpose)
6205             return p->value;
6206           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6207             p = p->left;
6208           else
6209             p = p->right;
6210         }
6211     }
6212   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6213     {
6214       if (!VEC_empty (constructor_elt, constructor_elements)
6215           && (VEC_last (constructor_elt, constructor_elements)->index
6216               == field))
6217         return VEC_last (constructor_elt, constructor_elements)->value;
6218     }
6219   return 0;
6220 }
6221
6222 /* "Output" the next constructor element.
6223    At top level, really output it to assembler code now.
6224    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6225    TYPE is the data type that the containing data type wants here.
6226    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6227    If VALUE is a string constant, STRICT_STRING is true if it is
6228    unparenthesized or we should not warn here for it being parenthesized.
6229    For other types of VALUE, STRICT_STRING is not used.
6230
6231    PENDING if non-nil means output pending elements that belong
6232    right after this element.  (PENDING is normally 1;
6233    it is 0 while outputting pending elements, to avoid recursion.)  */
6234
6235 static void
6236 output_init_element (tree value, bool strict_string, tree type, tree field,
6237                      int pending)
6238 {
6239   constructor_elt *celt;
6240
6241   if (type == error_mark_node || value == error_mark_node)
6242     {
6243       constructor_erroneous = 1;
6244       return;
6245     }
6246   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6247       && (TREE_CODE (value) == STRING_CST
6248           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6249       && !(TREE_CODE (value) == STRING_CST
6250            && TREE_CODE (type) == ARRAY_TYPE
6251            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6252       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6253                      TYPE_MAIN_VARIANT (type)))
6254     value = array_to_pointer_conversion (value);
6255
6256   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6257       && require_constant_value && !flag_isoc99 && pending)
6258     {
6259       /* As an extension, allow initializing objects with static storage
6260          duration with compound literals (which are then treated just as
6261          the brace enclosed list they contain).  */
6262       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6263       value = DECL_INITIAL (decl);
6264     }
6265
6266   if (value == error_mark_node)
6267     constructor_erroneous = 1;
6268   else if (!TREE_CONSTANT (value))
6269     constructor_constant = 0;
6270   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6271            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6272                 || TREE_CODE (constructor_type) == UNION_TYPE)
6273                && DECL_C_BIT_FIELD (field)
6274                && TREE_CODE (value) != INTEGER_CST))
6275     constructor_simple = 0;
6276
6277   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6278     {
6279       if (require_constant_value)
6280         {
6281           error_init ("initializer element is not constant");
6282           value = error_mark_node;
6283         }
6284       else if (require_constant_elements)
6285         pedwarn ("initializer element is not computable at load time");
6286     }
6287
6288   /* If this field is empty (and not at the end of structure),
6289      don't do anything other than checking the initializer.  */
6290   if (field
6291       && (TREE_TYPE (field) == error_mark_node
6292           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6293               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6294               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6295                   || TREE_CHAIN (field)))))
6296     return;
6297
6298   value = digest_init (type, value, strict_string, require_constant_value);
6299   if (value == error_mark_node)
6300     {
6301       constructor_erroneous = 1;
6302       return;
6303     }
6304
6305   /* If this element doesn't come next in sequence,
6306      put it on constructor_pending_elts.  */
6307   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6308       && (!constructor_incremental
6309           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6310     {
6311       if (constructor_incremental
6312           && tree_int_cst_lt (field, constructor_unfilled_index))
6313         set_nonincremental_init ();
6314
6315       add_pending_init (field, value);
6316       return;
6317     }
6318   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6319            && (!constructor_incremental
6320                || field != constructor_unfilled_fields))
6321     {
6322       /* We do this for records but not for unions.  In a union,
6323          no matter which field is specified, it can be initialized
6324          right away since it starts at the beginning of the union.  */
6325       if (constructor_incremental)
6326         {
6327           if (!constructor_unfilled_fields)
6328             set_nonincremental_init ();
6329           else
6330             {
6331               tree bitpos, unfillpos;
6332
6333               bitpos = bit_position (field);
6334               unfillpos = bit_position (constructor_unfilled_fields);
6335
6336               if (tree_int_cst_lt (bitpos, unfillpos))
6337                 set_nonincremental_init ();
6338             }
6339         }
6340
6341       add_pending_init (field, value);
6342       return;
6343     }
6344   else if (TREE_CODE (constructor_type) == UNION_TYPE
6345            && !VEC_empty (constructor_elt, constructor_elements))
6346     {
6347       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6348                                        constructor_elements)->value))
6349         warning_init (0, "initialized field with side-effects overwritten");
6350       else if (warn_override_init)
6351         warning_init (OPT_Woverride_init, "initialized field overwritten");
6352
6353       /* We can have just one union field set.  */
6354       constructor_elements = 0;
6355     }
6356
6357   /* Otherwise, output this element either to
6358      constructor_elements or to the assembler file.  */
6359
6360   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6361   celt->index = field;
6362   celt->value = value;
6363
6364   /* Advance the variable that indicates sequential elements output.  */
6365   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6366     constructor_unfilled_index
6367       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6368                     bitsize_one_node);
6369   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6370     {
6371       constructor_unfilled_fields
6372         = TREE_CHAIN (constructor_unfilled_fields);
6373
6374       /* Skip any nameless bit fields.  */
6375       while (constructor_unfilled_fields != 0
6376              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6377              && DECL_NAME (constructor_unfilled_fields) == 0)
6378         constructor_unfilled_fields =
6379           TREE_CHAIN (constructor_unfilled_fields);
6380     }
6381   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6382     constructor_unfilled_fields = 0;
6383
6384   /* Now output any pending elements which have become next.  */
6385   if (pending)
6386     output_pending_init_elements (0);
6387 }
6388
6389 /* Output any pending elements which have become next.
6390    As we output elements, constructor_unfilled_{fields,index}
6391    advances, which may cause other elements to become next;
6392    if so, they too are output.
6393
6394    If ALL is 0, we return when there are
6395    no more pending elements to output now.
6396
6397    If ALL is 1, we output space as necessary so that
6398    we can output all the pending elements.  */
6399
6400 static void
6401 output_pending_init_elements (int all)
6402 {
6403   struct init_node *elt = constructor_pending_elts;
6404   tree next;
6405
6406  retry:
6407
6408   /* Look through the whole pending tree.
6409      If we find an element that should be output now,
6410      output it.  Otherwise, set NEXT to the element
6411      that comes first among those still pending.  */
6412
6413   next = 0;
6414   while (elt)
6415     {
6416       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6417         {
6418           if (tree_int_cst_equal (elt->purpose,
6419                                   constructor_unfilled_index))
6420             output_init_element (elt->value, true,
6421                                  TREE_TYPE (constructor_type),
6422                                  constructor_unfilled_index, 0);
6423           else if (tree_int_cst_lt (constructor_unfilled_index,
6424                                     elt->purpose))
6425             {
6426               /* Advance to the next smaller node.  */
6427               if (elt->left)
6428                 elt = elt->left;
6429               else
6430                 {
6431                   /* We have reached the smallest node bigger than the
6432                      current unfilled index.  Fill the space first.  */
6433                   next = elt->purpose;
6434                   break;
6435                 }
6436             }
6437           else
6438             {
6439               /* Advance to the next bigger node.  */
6440               if (elt->right)
6441                 elt = elt->right;
6442               else
6443                 {
6444                   /* We have reached the biggest node in a subtree.  Find
6445                      the parent of it, which is the next bigger node.  */
6446                   while (elt->parent && elt->parent->right == elt)
6447                     elt = elt->parent;
6448                   elt = elt->parent;
6449                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6450                                               elt->purpose))
6451                     {
6452                       next = elt->purpose;
6453                       break;
6454                     }
6455                 }
6456             }
6457         }
6458       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6459                || TREE_CODE (constructor_type) == UNION_TYPE)
6460         {
6461           tree ctor_unfilled_bitpos, elt_bitpos;
6462
6463           /* If the current record is complete we are done.  */
6464           if (constructor_unfilled_fields == 0)
6465             break;
6466
6467           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6468           elt_bitpos = bit_position (elt->purpose);
6469           /* We can't compare fields here because there might be empty
6470              fields in between.  */
6471           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6472             {
6473               constructor_unfilled_fields = elt->purpose;
6474               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6475                                    elt->purpose, 0);
6476             }
6477           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6478             {
6479               /* Advance to the next smaller node.  */
6480               if (elt->left)
6481                 elt = elt->left;
6482               else
6483                 {
6484                   /* We have reached the smallest node bigger than the
6485                      current unfilled field.  Fill the space first.  */
6486                   next = elt->purpose;
6487                   break;
6488                 }
6489             }
6490           else
6491             {
6492               /* Advance to the next bigger node.  */
6493               if (elt->right)
6494                 elt = elt->right;
6495               else
6496                 {
6497                   /* We have reached the biggest node in a subtree.  Find
6498                      the parent of it, which is the next bigger node.  */
6499                   while (elt->parent && elt->parent->right == elt)
6500                     elt = elt->parent;
6501                   elt = elt->parent;
6502                   if (elt
6503                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6504                                            bit_position (elt->purpose))))
6505                     {
6506                       next = elt->purpose;
6507                       break;
6508                     }
6509                 }
6510             }
6511         }
6512     }
6513
6514   /* Ordinarily return, but not if we want to output all
6515      and there are elements left.  */
6516   if (!(all && next != 0))
6517     return;
6518
6519   /* If it's not incremental, just skip over the gap, so that after
6520      jumping to retry we will output the next successive element.  */
6521   if (TREE_CODE (constructor_type) == RECORD_TYPE
6522       || TREE_CODE (constructor_type) == UNION_TYPE)
6523     constructor_unfilled_fields = next;
6524   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6525     constructor_unfilled_index = next;
6526
6527   /* ELT now points to the node in the pending tree with the next
6528      initializer to output.  */
6529   goto retry;
6530 }
6531 \f
6532 /* Add one non-braced element to the current constructor level.
6533    This adjusts the current position within the constructor's type.
6534    This may also start or terminate implicit levels
6535    to handle a partly-braced initializer.
6536
6537    Once this has found the correct level for the new element,
6538    it calls output_init_element.  */
6539
6540 void
6541 process_init_element (struct c_expr value)
6542 {
6543   tree orig_value = value.value;
6544   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6545   bool strict_string = value.original_code == STRING_CST;
6546
6547   designator_depth = 0;
6548   designator_erroneous = 0;
6549
6550   /* Handle superfluous braces around string cst as in
6551      char x[] = {"foo"}; */
6552   if (string_flag
6553       && constructor_type
6554       && TREE_CODE (constructor_type) == ARRAY_TYPE
6555       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6556       && integer_zerop (constructor_unfilled_index))
6557     {
6558       if (constructor_stack->replacement_value.value)
6559         error_init ("excess elements in char array initializer");
6560       constructor_stack->replacement_value = value;
6561       return;
6562     }
6563
6564   if (constructor_stack->replacement_value.value != 0)
6565     {
6566       error_init ("excess elements in struct initializer");
6567       return;
6568     }
6569
6570   /* Ignore elements of a brace group if it is entirely superfluous
6571      and has already been diagnosed.  */
6572   if (constructor_type == 0)
6573     return;
6574
6575   /* If we've exhausted any levels that didn't have braces,
6576      pop them now.  */
6577   while (constructor_stack->implicit)
6578     {
6579       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6580            || TREE_CODE (constructor_type) == UNION_TYPE)
6581           && constructor_fields == 0)
6582         process_init_element (pop_init_level (1));
6583       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6584                && (constructor_max_index == 0
6585                    || tree_int_cst_lt (constructor_max_index,
6586                                        constructor_index)))
6587         process_init_element (pop_init_level (1));
6588       else
6589         break;
6590     }
6591
6592   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6593   if (constructor_range_stack)
6594     {
6595       /* If value is a compound literal and we'll be just using its
6596          content, don't put it into a SAVE_EXPR.  */
6597       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6598           || !require_constant_value
6599           || flag_isoc99)
6600         value.value = save_expr (value.value);
6601     }
6602
6603   while (1)
6604     {
6605       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6606         {
6607           tree fieldtype;
6608           enum tree_code fieldcode;
6609
6610           if (constructor_fields == 0)
6611             {
6612               pedwarn_init ("excess elements in struct initializer");
6613               break;
6614             }
6615
6616           fieldtype = TREE_TYPE (constructor_fields);
6617           if (fieldtype != error_mark_node)
6618             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6619           fieldcode = TREE_CODE (fieldtype);
6620
6621           /* Error for non-static initialization of a flexible array member.  */
6622           if (fieldcode == ARRAY_TYPE
6623               && !require_constant_value
6624               && TYPE_SIZE (fieldtype) == NULL_TREE
6625               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6626             {
6627               error_init ("non-static initialization of a flexible array member");
6628               break;
6629             }
6630
6631           /* Accept a string constant to initialize a subarray.  */
6632           if (value.value != 0
6633               && fieldcode == ARRAY_TYPE
6634               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6635               && string_flag)
6636             value.value = orig_value;
6637           /* Otherwise, if we have come to a subaggregate,
6638              and we don't have an element of its type, push into it.  */
6639           else if (value.value != 0
6640                    && value.value != error_mark_node
6641                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6642                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6643                        || fieldcode == UNION_TYPE))
6644             {
6645               push_init_level (1);
6646               continue;
6647             }
6648
6649           if (value.value)
6650             {
6651               push_member_name (constructor_fields);
6652               output_init_element (value.value, strict_string,
6653                                    fieldtype, constructor_fields, 1);
6654               RESTORE_SPELLING_DEPTH (constructor_depth);
6655             }
6656           else
6657             /* Do the bookkeeping for an element that was
6658                directly output as a constructor.  */
6659             {
6660               /* For a record, keep track of end position of last field.  */
6661               if (DECL_SIZE (constructor_fields))
6662                 constructor_bit_index
6663                   = size_binop (PLUS_EXPR,
6664                                 bit_position (constructor_fields),
6665                                 DECL_SIZE (constructor_fields));
6666
6667               /* If the current field was the first one not yet written out,
6668                  it isn't now, so update.  */
6669               if (constructor_unfilled_fields == constructor_fields)
6670                 {
6671                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6672                   /* Skip any nameless bit fields.  */
6673                   while (constructor_unfilled_fields != 0
6674                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6675                          && DECL_NAME (constructor_unfilled_fields) == 0)
6676                     constructor_unfilled_fields =
6677                       TREE_CHAIN (constructor_unfilled_fields);
6678                 }
6679             }
6680
6681           constructor_fields = TREE_CHAIN (constructor_fields);
6682           /* Skip any nameless bit fields at the beginning.  */
6683           while (constructor_fields != 0
6684                  && DECL_C_BIT_FIELD (constructor_fields)
6685                  && DECL_NAME (constructor_fields) == 0)
6686             constructor_fields = TREE_CHAIN (constructor_fields);
6687         }
6688       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6689         {
6690           tree fieldtype;
6691           enum tree_code fieldcode;
6692
6693           if (constructor_fields == 0)
6694             {
6695               pedwarn_init ("excess elements in union initializer");
6696               break;
6697             }
6698
6699           fieldtype = TREE_TYPE (constructor_fields);
6700           if (fieldtype != error_mark_node)
6701             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6702           fieldcode = TREE_CODE (fieldtype);
6703
6704           /* Warn that traditional C rejects initialization of unions.
6705              We skip the warning if the value is zero.  This is done
6706              under the assumption that the zero initializer in user
6707              code appears conditioned on e.g. __STDC__ to avoid
6708              "missing initializer" warnings and relies on default
6709              initialization to zero in the traditional C case.
6710              We also skip the warning if the initializer is designated,
6711              again on the assumption that this must be conditional on
6712              __STDC__ anyway (and we've already complained about the
6713              member-designator already).  */
6714           if (!in_system_header && !constructor_designated
6715               && !(value.value && (integer_zerop (value.value)
6716                                    || real_zerop (value.value))))
6717             warning (OPT_Wtraditional, "traditional C rejects initialization "
6718                      "of unions");
6719
6720           /* Accept a string constant to initialize a subarray.  */
6721           if (value.value != 0
6722               && fieldcode == ARRAY_TYPE
6723               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6724               && string_flag)
6725             value.value = orig_value;
6726           /* Otherwise, if we have come to a subaggregate,
6727              and we don't have an element of its type, push into it.  */
6728           else if (value.value != 0
6729                    && value.value != error_mark_node
6730                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6731                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6732                        || fieldcode == UNION_TYPE))
6733             {
6734               push_init_level (1);
6735               continue;
6736             }
6737
6738           if (value.value)
6739             {
6740               push_member_name (constructor_fields);
6741               output_init_element (value.value, strict_string,
6742                                    fieldtype, constructor_fields, 1);
6743               RESTORE_SPELLING_DEPTH (constructor_depth);
6744             }
6745           else
6746             /* Do the bookkeeping for an element that was
6747                directly output as a constructor.  */
6748             {
6749               constructor_bit_index = DECL_SIZE (constructor_fields);
6750               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6751             }
6752
6753           constructor_fields = 0;
6754         }
6755       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6756         {
6757           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6758           enum tree_code eltcode = TREE_CODE (elttype);
6759
6760           /* Accept a string constant to initialize a subarray.  */
6761           if (value.value != 0
6762               && eltcode == ARRAY_TYPE
6763               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6764               && string_flag)
6765             value.value = orig_value;
6766           /* Otherwise, if we have come to a subaggregate,
6767              and we don't have an element of its type, push into it.  */
6768           else if (value.value != 0
6769                    && value.value != error_mark_node
6770                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6771                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6772                        || eltcode == UNION_TYPE))
6773             {
6774               push_init_level (1);
6775               continue;
6776             }
6777
6778           if (constructor_max_index != 0
6779               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6780                   || integer_all_onesp (constructor_max_index)))
6781             {
6782               pedwarn_init ("excess elements in array initializer");
6783               break;
6784             }
6785
6786           /* Now output the actual element.  */
6787           if (value.value)
6788             {
6789               push_array_bounds (tree_low_cst (constructor_index, 1));
6790               output_init_element (value.value, strict_string,
6791                                    elttype, constructor_index, 1);
6792               RESTORE_SPELLING_DEPTH (constructor_depth);
6793             }
6794
6795           constructor_index
6796             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6797
6798           if (!value.value)
6799             /* If we are doing the bookkeeping for an element that was
6800                directly output as a constructor, we must update
6801                constructor_unfilled_index.  */
6802             constructor_unfilled_index = constructor_index;
6803         }
6804       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6805         {
6806           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6807
6808          /* Do a basic check of initializer size.  Note that vectors
6809             always have a fixed size derived from their type.  */
6810           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6811             {
6812               pedwarn_init ("excess elements in vector initializer");
6813               break;
6814             }
6815
6816           /* Now output the actual element.  */
6817           if (value.value)
6818             output_init_element (value.value, strict_string,
6819                                  elttype, constructor_index, 1);
6820
6821           constructor_index
6822             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6823
6824           if (!value.value)
6825             /* If we are doing the bookkeeping for an element that was
6826                directly output as a constructor, we must update
6827                constructor_unfilled_index.  */
6828             constructor_unfilled_index = constructor_index;
6829         }
6830
6831       /* Handle the sole element allowed in a braced initializer
6832          for a scalar variable.  */
6833       else if (constructor_type != error_mark_node
6834                && constructor_fields == 0)
6835         {
6836           pedwarn_init ("excess elements in scalar initializer");
6837           break;
6838         }
6839       else
6840         {
6841           if (value.value)
6842             output_init_element (value.value, strict_string,
6843                                  constructor_type, NULL_TREE, 1);
6844           constructor_fields = 0;
6845         }
6846
6847       /* Handle range initializers either at this level or anywhere higher
6848          in the designator stack.  */
6849       if (constructor_range_stack)
6850         {
6851           struct constructor_range_stack *p, *range_stack;
6852           int finish = 0;
6853
6854           range_stack = constructor_range_stack;
6855           constructor_range_stack = 0;
6856           while (constructor_stack != range_stack->stack)
6857             {
6858               gcc_assert (constructor_stack->implicit);
6859               process_init_element (pop_init_level (1));
6860             }
6861           for (p = range_stack;
6862                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6863                p = p->prev)
6864             {
6865               gcc_assert (constructor_stack->implicit);
6866               process_init_element (pop_init_level (1));
6867             }
6868
6869           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6870           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6871             finish = 1;
6872
6873           while (1)
6874             {
6875               constructor_index = p->index;
6876               constructor_fields = p->fields;
6877               if (finish && p->range_end && p->index == p->range_start)
6878                 {
6879                   finish = 0;
6880                   p->prev = 0;
6881                 }
6882               p = p->next;
6883               if (!p)
6884                 break;
6885               push_init_level (2);
6886               p->stack = constructor_stack;
6887               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6888                 p->index = p->range_start;
6889             }
6890
6891           if (!finish)
6892             constructor_range_stack = range_stack;
6893           continue;
6894         }
6895
6896       break;
6897     }
6898
6899   constructor_range_stack = 0;
6900 }
6901 \f
6902 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6903    (guaranteed to be 'volatile' or null) and ARGS (represented using
6904    an ASM_EXPR node).  */
6905 tree
6906 build_asm_stmt (tree cv_qualifier, tree args)
6907 {
6908   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6909     ASM_VOLATILE_P (args) = 1;
6910   return add_stmt (args);
6911 }
6912
6913 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6914    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6915    SIMPLE indicates whether there was anything at all after the
6916    string in the asm expression -- asm("blah") and asm("blah" : )
6917    are subtly different.  We use a ASM_EXPR node to represent this.  */
6918 tree
6919 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6920                 bool simple)
6921 {
6922   tree tail;
6923   tree args;
6924   int i;
6925   const char *constraint;
6926   const char **oconstraints;
6927   bool allows_mem, allows_reg, is_inout;
6928   int ninputs, noutputs;
6929
6930   ninputs = list_length (inputs);
6931   noutputs = list_length (outputs);
6932   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6933
6934   string = resolve_asm_operand_names (string, outputs, inputs);
6935
6936   /* Remove output conversions that change the type but not the mode.  */
6937   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6938     {
6939       tree output = TREE_VALUE (tail);
6940
6941       /* ??? Really, this should not be here.  Users should be using a
6942          proper lvalue, dammit.  But there's a long history of using casts
6943          in the output operands.  In cases like longlong.h, this becomes a
6944          primitive form of typechecking -- if the cast can be removed, then
6945          the output operand had a type of the proper width; otherwise we'll
6946          get an error.  Gross, but ...  */
6947       STRIP_NOPS (output);
6948
6949       if (!lvalue_or_else (output, lv_asm))
6950         output = error_mark_node;
6951
6952       if (output != error_mark_node
6953           && (TREE_READONLY (output)
6954               || TYPE_READONLY (TREE_TYPE (output))
6955               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6956                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6957                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6958         readonly_error (output, lv_asm);
6959
6960       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6961       oconstraints[i] = constraint;
6962
6963       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6964                                    &allows_mem, &allows_reg, &is_inout))
6965         {
6966           /* If the operand is going to end up in memory,
6967              mark it addressable.  */
6968           if (!allows_reg && !c_mark_addressable (output))
6969             output = error_mark_node;
6970         }
6971       else
6972         output = error_mark_node;
6973
6974       TREE_VALUE (tail) = output;
6975     }
6976
6977   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6978     {
6979       tree input;
6980
6981       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6982       input = TREE_VALUE (tail);
6983
6984       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6985                                   oconstraints, &allows_mem, &allows_reg))
6986         {
6987           /* If the operand is going to end up in memory,
6988              mark it addressable.  */
6989           if (!allows_reg && allows_mem)
6990             {
6991               /* Strip the nops as we allow this case.  FIXME, this really
6992                  should be rejected or made deprecated.  */
6993               STRIP_NOPS (input);
6994               if (!c_mark_addressable (input))
6995                 input = error_mark_node;
6996           }
6997         }
6998       else
6999         input = error_mark_node;
7000
7001       TREE_VALUE (tail) = input;
7002     }
7003
7004   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7005
7006   /* asm statements without outputs, including simple ones, are treated
7007      as volatile.  */
7008   ASM_INPUT_P (args) = simple;
7009   ASM_VOLATILE_P (args) = (noutputs == 0);
7010
7011   return args;
7012 }
7013 \f
7014 /* Generate a goto statement to LABEL.  */
7015
7016 tree
7017 c_finish_goto_label (tree label)
7018 {
7019   tree decl = lookup_label (label);
7020   if (!decl)
7021     return NULL_TREE;
7022
7023   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7024     {
7025       error ("jump into statement expression");
7026       return NULL_TREE;
7027     }
7028
7029   if (C_DECL_UNJUMPABLE_VM (decl))
7030     {
7031       error ("jump into scope of identifier with variably modified type");
7032       return NULL_TREE;
7033     }
7034
7035   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7036     {
7037       /* No jump from outside this statement expression context, so
7038          record that there is a jump from within this context.  */
7039       struct c_label_list *nlist;
7040       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7041       nlist->next = label_context_stack_se->labels_used;
7042       nlist->label = decl;
7043       label_context_stack_se->labels_used = nlist;
7044     }
7045
7046   if (!C_DECL_UNDEFINABLE_VM (decl))
7047     {
7048       /* No jump from outside this context context of identifiers with
7049          variably modified type, so record that there is a jump from
7050          within this context.  */
7051       struct c_label_list *nlist;
7052       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7053       nlist->next = label_context_stack_vm->labels_used;
7054       nlist->label = decl;
7055       label_context_stack_vm->labels_used = nlist;
7056     }
7057
7058   TREE_USED (decl) = 1;
7059   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7060 }
7061
7062 /* Generate a computed goto statement to EXPR.  */
7063
7064 tree
7065 c_finish_goto_ptr (tree expr)
7066 {
7067   if (pedantic)
7068     pedwarn ("ISO C forbids %<goto *expr;%>");
7069   expr = convert (ptr_type_node, expr);
7070   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7071 }
7072
7073 /* Generate a C `return' statement.  RETVAL is the expression for what
7074    to return, or a null pointer for `return;' with no value.  */
7075
7076 tree
7077 c_finish_return (tree retval)
7078 {
7079   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7080   bool no_warning = false;
7081
7082   if (TREE_THIS_VOLATILE (current_function_decl))
7083     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7084
7085   if (!retval)
7086     {
7087       current_function_returns_null = 1;
7088       if ((warn_return_type || flag_isoc99)
7089           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7090         {
7091           pedwarn_c99 ("%<return%> with no value, in "
7092                        "function returning non-void");
7093           no_warning = true;
7094         }
7095     }
7096   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7097     {
7098       current_function_returns_null = 1;
7099       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7100         pedwarn ("%<return%> with a value, in function returning void");
7101       else if (pedantic)
7102         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7103     }
7104   else
7105     {
7106       tree t = convert_for_assignment (valtype, retval, ic_return,
7107                                        NULL_TREE, NULL_TREE, 0);
7108       tree res = DECL_RESULT (current_function_decl);
7109       tree inner;
7110
7111       current_function_returns_value = 1;
7112       if (t == error_mark_node)
7113         return NULL_TREE;
7114
7115       inner = t = convert (TREE_TYPE (res), t);
7116
7117       /* Strip any conversions, additions, and subtractions, and see if
7118          we are returning the address of a local variable.  Warn if so.  */
7119       while (1)
7120         {
7121           switch (TREE_CODE (inner))
7122             {
7123             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
7124             case PLUS_EXPR:
7125               inner = TREE_OPERAND (inner, 0);
7126               continue;
7127
7128             case MINUS_EXPR:
7129               /* If the second operand of the MINUS_EXPR has a pointer
7130                  type (or is converted from it), this may be valid, so
7131                  don't give a warning.  */
7132               {
7133                 tree op1 = TREE_OPERAND (inner, 1);
7134
7135                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7136                        && (TREE_CODE (op1) == NOP_EXPR
7137                            || TREE_CODE (op1) == NON_LVALUE_EXPR
7138                            || TREE_CODE (op1) == CONVERT_EXPR))
7139                   op1 = TREE_OPERAND (op1, 0);
7140
7141                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7142                   break;
7143
7144                 inner = TREE_OPERAND (inner, 0);
7145                 continue;
7146               }
7147
7148             case ADDR_EXPR:
7149               inner = TREE_OPERAND (inner, 0);
7150
7151               while (REFERENCE_CLASS_P (inner)
7152                      && TREE_CODE (inner) != INDIRECT_REF)
7153                 inner = TREE_OPERAND (inner, 0);
7154
7155               if (DECL_P (inner)
7156                   && !DECL_EXTERNAL (inner)
7157                   && !TREE_STATIC (inner)
7158                   && DECL_CONTEXT (inner) == current_function_decl)
7159                 warning (0, "function returns address of local variable");
7160               break;
7161
7162             default:
7163               break;
7164             }
7165
7166           break;
7167         }
7168
7169       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7170     }
7171
7172   ret_stmt = build_stmt (RETURN_EXPR, retval);
7173   TREE_NO_WARNING (ret_stmt) |= no_warning;
7174   return add_stmt (ret_stmt);
7175 }
7176 \f
7177 struct c_switch {
7178   /* The SWITCH_EXPR being built.  */
7179   tree switch_expr;
7180
7181   /* The original type of the testing expression, i.e. before the
7182      default conversion is applied.  */
7183   tree orig_type;
7184
7185   /* A splay-tree mapping the low element of a case range to the high
7186      element, or NULL_TREE if there is no high element.  Used to
7187      determine whether or not a new case label duplicates an old case
7188      label.  We need a tree, rather than simply a hash table, because
7189      of the GNU case range extension.  */
7190   splay_tree cases;
7191
7192   /* Number of nested statement expressions within this switch
7193      statement; if nonzero, case and default labels may not
7194      appear.  */
7195   unsigned int blocked_stmt_expr;
7196
7197   /* Scope of outermost declarations of identifiers with variably
7198      modified type within this switch statement; if nonzero, case and
7199      default labels may not appear.  */
7200   unsigned int blocked_vm;
7201
7202   /* The next node on the stack.  */
7203   struct c_switch *next;
7204 };
7205
7206 /* A stack of the currently active switch statements.  The innermost
7207    switch statement is on the top of the stack.  There is no need to
7208    mark the stack for garbage collection because it is only active
7209    during the processing of the body of a function, and we never
7210    collect at that point.  */
7211
7212 struct c_switch *c_switch_stack;
7213
7214 /* Start a C switch statement, testing expression EXP.  Return the new
7215    SWITCH_EXPR.  */
7216
7217 tree
7218 c_start_case (tree exp)
7219 {
7220   tree orig_type = error_mark_node;
7221   struct c_switch *cs;
7222
7223   if (exp != error_mark_node)
7224     {
7225       orig_type = TREE_TYPE (exp);
7226
7227       if (!INTEGRAL_TYPE_P (orig_type))
7228         {
7229           if (orig_type != error_mark_node)
7230             {
7231               error ("switch quantity not an integer");
7232               orig_type = error_mark_node;
7233             }
7234           exp = integer_zero_node;
7235         }
7236       else
7237         {
7238           tree type = TYPE_MAIN_VARIANT (orig_type);
7239
7240           if (!in_system_header
7241               && (type == long_integer_type_node
7242                   || type == long_unsigned_type_node))
7243             warning (OPT_Wtraditional, "%<long%> switch expression not "
7244                      "converted to %<int%> in ISO C");
7245
7246           exp = default_conversion (exp);
7247         }
7248     }
7249
7250   /* Add this new SWITCH_EXPR to the stack.  */
7251   cs = XNEW (struct c_switch);
7252   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7253   cs->orig_type = orig_type;
7254   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7255   cs->blocked_stmt_expr = 0;
7256   cs->blocked_vm = 0;
7257   cs->next = c_switch_stack;
7258   c_switch_stack = cs;
7259
7260   return add_stmt (cs->switch_expr);
7261 }
7262
7263 /* Process a case label.  */
7264
7265 tree
7266 do_case (tree low_value, tree high_value)
7267 {
7268   tree label = NULL_TREE;
7269
7270   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7271       && !c_switch_stack->blocked_vm)
7272     {
7273       label = c_add_case_label (c_switch_stack->cases,
7274                                 SWITCH_COND (c_switch_stack->switch_expr),
7275                                 c_switch_stack->orig_type,
7276                                 low_value, high_value);
7277       if (label == error_mark_node)
7278         label = NULL_TREE;
7279     }
7280   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7281     {
7282       if (low_value)
7283         error ("case label in statement expression not containing "
7284                "enclosing switch statement");
7285       else
7286         error ("%<default%> label in statement expression not containing "
7287                "enclosing switch statement");
7288     }
7289   else if (c_switch_stack && c_switch_stack->blocked_vm)
7290     {
7291       if (low_value)
7292         error ("case label in scope of identifier with variably modified "
7293                "type not containing enclosing switch statement");
7294       else
7295         error ("%<default%> label in scope of identifier with variably "
7296                "modified type not containing enclosing switch statement");
7297     }
7298   else if (low_value)
7299     error ("case label not within a switch statement");
7300   else
7301     error ("%<default%> label not within a switch statement");
7302
7303   return label;
7304 }
7305
7306 /* Finish the switch statement.  */
7307
7308 void
7309 c_finish_case (tree body)
7310 {
7311   struct c_switch *cs = c_switch_stack;
7312   location_t switch_location;
7313
7314   SWITCH_BODY (cs->switch_expr) = body;
7315
7316   /* We must not be within a statement expression nested in the switch
7317      at this point; we might, however, be within the scope of an
7318      identifier with variably modified type nested in the switch.  */
7319   gcc_assert (!cs->blocked_stmt_expr);
7320
7321   /* Emit warnings as needed.  */
7322   if (EXPR_HAS_LOCATION (cs->switch_expr))
7323     switch_location = EXPR_LOCATION (cs->switch_expr);
7324   else
7325     switch_location = input_location;
7326   c_do_switch_warnings (cs->cases, switch_location,
7327                         TREE_TYPE (cs->switch_expr),
7328                         SWITCH_COND (cs->switch_expr));
7329
7330   /* Pop the stack.  */
7331   c_switch_stack = cs->next;
7332   splay_tree_delete (cs->cases);
7333   XDELETE (cs);
7334 }
7335 \f
7336 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7337    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7338    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7339    statement, and was not surrounded with parenthesis.  */
7340
7341 void
7342 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7343                   tree else_block, bool nested_if)
7344 {
7345   tree stmt;
7346
7347   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7348   if (warn_parentheses && nested_if && else_block == NULL)
7349     {
7350       tree inner_if = then_block;
7351
7352       /* We know from the grammar productions that there is an IF nested
7353          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7354          it might not be exactly THEN_BLOCK, but should be the last
7355          non-container statement within.  */
7356       while (1)
7357         switch (TREE_CODE (inner_if))
7358           {
7359           case COND_EXPR:
7360             goto found;
7361           case BIND_EXPR:
7362             inner_if = BIND_EXPR_BODY (inner_if);
7363             break;
7364           case STATEMENT_LIST:
7365             inner_if = expr_last (then_block);
7366             break;
7367           case TRY_FINALLY_EXPR:
7368           case TRY_CATCH_EXPR:
7369             inner_if = TREE_OPERAND (inner_if, 0);
7370             break;
7371           default:
7372             gcc_unreachable ();
7373           }
7374     found:
7375
7376       if (COND_EXPR_ELSE (inner_if))
7377          warning (OPT_Wparentheses,
7378                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7379                   &if_locus);
7380     }
7381
7382   empty_if_body_warning (then_block, else_block);
7383
7384   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7385   SET_EXPR_LOCATION (stmt, if_locus);
7386   add_stmt (stmt);
7387 }
7388
7389 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7390    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7391    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7392    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7393    the continue label.  Everything is allowed to be NULL.  */
7394
7395 void
7396 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7397                tree blab, tree clab, bool cond_is_first)
7398 {
7399   tree entry = NULL, exit = NULL, t;
7400
7401   /* If the condition is zero don't generate a loop construct.  */
7402   if (cond && integer_zerop (cond))
7403     {
7404       if (cond_is_first)
7405         {
7406           t = build_and_jump (&blab);
7407           SET_EXPR_LOCATION (t, start_locus);
7408           add_stmt (t);
7409         }
7410     }
7411   else
7412     {
7413       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7414
7415       /* If we have an exit condition, then we build an IF with gotos either
7416          out of the loop, or to the top of it.  If there's no exit condition,
7417          then we just build a jump back to the top.  */
7418       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7419
7420       if (cond && !integer_nonzerop (cond))
7421         {
7422           /* Canonicalize the loop condition to the end.  This means
7423              generating a branch to the loop condition.  Reuse the
7424              continue label, if possible.  */
7425           if (cond_is_first)
7426             {
7427               if (incr || !clab)
7428                 {
7429                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7430                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7431                 }
7432               else
7433                 t = build1 (GOTO_EXPR, void_type_node, clab);
7434               SET_EXPR_LOCATION (t, start_locus);
7435               add_stmt (t);
7436             }
7437
7438           t = build_and_jump (&blab);
7439           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7440           if (cond_is_first)
7441             SET_EXPR_LOCATION (exit, start_locus);
7442           else
7443             SET_EXPR_LOCATION (exit, input_location);
7444         }
7445
7446       add_stmt (top);
7447     }
7448
7449   if (body)
7450     add_stmt (body);
7451   if (clab)
7452     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7453   if (incr)
7454     add_stmt (incr);
7455   if (entry)
7456     add_stmt (entry);
7457   if (exit)
7458     add_stmt (exit);
7459   if (blab)
7460     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7461 }
7462
7463 tree
7464 c_finish_bc_stmt (tree *label_p, bool is_break)
7465 {
7466   bool skip;
7467   tree label = *label_p;
7468
7469   /* In switch statements break is sometimes stylistically used after
7470      a return statement.  This can lead to spurious warnings about
7471      control reaching the end of a non-void function when it is
7472      inlined.  Note that we are calling block_may_fallthru with
7473      language specific tree nodes; this works because
7474      block_may_fallthru returns true when given something it does not
7475      understand.  */
7476   skip = !block_may_fallthru (cur_stmt_list);
7477
7478   if (!label)
7479     {
7480       if (!skip)
7481         *label_p = label = create_artificial_label ();
7482     }
7483   else if (TREE_CODE (label) == LABEL_DECL)
7484     ;
7485   else switch (TREE_INT_CST_LOW (label))
7486     {
7487     case 0:
7488       if (is_break)
7489         error ("break statement not within loop or switch");
7490       else
7491         error ("continue statement not within a loop");
7492       return NULL_TREE;
7493
7494     case 1:
7495       gcc_assert (is_break);
7496       error ("break statement used with OpenMP for loop");
7497       return NULL_TREE;
7498
7499     default:
7500       gcc_unreachable ();
7501     }
7502
7503   if (skip)
7504     return NULL_TREE;
7505
7506   if (!is_break)
7507     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7508
7509   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7510 }
7511
7512 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7513
7514 static void
7515 emit_side_effect_warnings (tree expr)
7516 {
7517   if (expr == error_mark_node)
7518     ;
7519   else if (!TREE_SIDE_EFFECTS (expr))
7520     {
7521       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7522         warning (OPT_Wunused_value, "%Hstatement with no effect",
7523                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7524     }
7525   else
7526     warn_if_unused_value (expr, input_location);
7527 }
7528
7529 /* Process an expression as if it were a complete statement.  Emit
7530    diagnostics, but do not call ADD_STMT.  */
7531
7532 tree
7533 c_process_expr_stmt (tree expr)
7534 {
7535   if (!expr)
7536     return NULL_TREE;
7537
7538   if (warn_sequence_point)
7539     verify_sequence_points (expr);
7540
7541   if (TREE_TYPE (expr) != error_mark_node
7542       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7543       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7544     error ("expression statement has incomplete type");
7545
7546   /* If we're not processing a statement expression, warn about unused values.
7547      Warnings for statement expressions will be emitted later, once we figure
7548      out which is the result.  */
7549   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7550       && warn_unused_value)
7551     emit_side_effect_warnings (expr);
7552
7553   /* If the expression is not of a type to which we cannot assign a line
7554      number, wrap the thing in a no-op NOP_EXPR.  */
7555   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7556     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7557
7558   if (CAN_HAVE_LOCATION_P (expr))
7559     SET_EXPR_LOCATION (expr, input_location);
7560
7561   return expr;
7562 }
7563
7564 /* Emit an expression as a statement.  */
7565
7566 tree
7567 c_finish_expr_stmt (tree expr)
7568 {
7569   if (expr)
7570     return add_stmt (c_process_expr_stmt (expr));
7571   else
7572     return NULL;
7573 }
7574
7575 /* Do the opposite and emit a statement as an expression.  To begin,
7576    create a new binding level and return it.  */
7577
7578 tree
7579 c_begin_stmt_expr (void)
7580 {
7581   tree ret;
7582   struct c_label_context_se *nstack;
7583   struct c_label_list *glist;
7584
7585   /* We must force a BLOCK for this level so that, if it is not expanded
7586      later, there is a way to turn off the entire subtree of blocks that
7587      are contained in it.  */
7588   keep_next_level ();
7589   ret = c_begin_compound_stmt (true);
7590   if (c_switch_stack)
7591     {
7592       c_switch_stack->blocked_stmt_expr++;
7593       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7594     }
7595   for (glist = label_context_stack_se->labels_used;
7596        glist != NULL;
7597        glist = glist->next)
7598     {
7599       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7600     }
7601   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7602   nstack->labels_def = NULL;
7603   nstack->labels_used = NULL;
7604   nstack->next = label_context_stack_se;
7605   label_context_stack_se = nstack;
7606
7607   /* Mark the current statement list as belonging to a statement list.  */
7608   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7609
7610   return ret;
7611 }
7612
7613 tree
7614 c_finish_stmt_expr (tree body)
7615 {
7616   tree last, type, tmp, val;
7617   tree *last_p;
7618   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7619
7620   body = c_end_compound_stmt (body, true);
7621   if (c_switch_stack)
7622     {
7623       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7624       c_switch_stack->blocked_stmt_expr--;
7625     }
7626   /* It is no longer possible to jump to labels defined within this
7627      statement expression.  */
7628   for (dlist = label_context_stack_se->labels_def;
7629        dlist != NULL;
7630        dlist = dlist->next)
7631     {
7632       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7633     }
7634   /* It is again possible to define labels with a goto just outside
7635      this statement expression.  */
7636   for (glist = label_context_stack_se->next->labels_used;
7637        glist != NULL;
7638        glist = glist->next)
7639     {
7640       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7641       glist_prev = glist;
7642     }
7643   if (glist_prev != NULL)
7644     glist_prev->next = label_context_stack_se->labels_used;
7645   else
7646     label_context_stack_se->next->labels_used
7647       = label_context_stack_se->labels_used;
7648   label_context_stack_se = label_context_stack_se->next;
7649
7650   /* Locate the last statement in BODY.  See c_end_compound_stmt
7651      about always returning a BIND_EXPR.  */
7652   last_p = &BIND_EXPR_BODY (body);
7653   last = BIND_EXPR_BODY (body);
7654
7655  continue_searching:
7656   if (TREE_CODE (last) == STATEMENT_LIST)
7657     {
7658       tree_stmt_iterator i;
7659
7660       /* This can happen with degenerate cases like ({ }).  No value.  */
7661       if (!TREE_SIDE_EFFECTS (last))
7662         return body;
7663
7664       /* If we're supposed to generate side effects warnings, process
7665          all of the statements except the last.  */
7666       if (warn_unused_value)
7667         {
7668           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7669             emit_side_effect_warnings (tsi_stmt (i));
7670         }
7671       else
7672         i = tsi_last (last);
7673       last_p = tsi_stmt_ptr (i);
7674       last = *last_p;
7675     }
7676
7677   /* If the end of the list is exception related, then the list was split
7678      by a call to push_cleanup.  Continue searching.  */
7679   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7680       || TREE_CODE (last) == TRY_CATCH_EXPR)
7681     {
7682       last_p = &TREE_OPERAND (last, 0);
7683       last = *last_p;
7684       goto continue_searching;
7685     }
7686
7687   /* In the case that the BIND_EXPR is not necessary, return the
7688      expression out from inside it.  */
7689   if (last == error_mark_node
7690       || (last == BIND_EXPR_BODY (body)
7691           && BIND_EXPR_VARS (body) == NULL))
7692     {
7693       /* Do not warn if the return value of a statement expression is
7694          unused.  */
7695       if (CAN_HAVE_LOCATION_P (last))
7696         TREE_NO_WARNING (last) = 1;
7697       return last;
7698     }
7699
7700   /* Extract the type of said expression.  */
7701   type = TREE_TYPE (last);
7702
7703   /* If we're not returning a value at all, then the BIND_EXPR that
7704      we already have is a fine expression to return.  */
7705   if (!type || VOID_TYPE_P (type))
7706     return body;
7707
7708   /* Now that we've located the expression containing the value, it seems
7709      silly to make voidify_wrapper_expr repeat the process.  Create a
7710      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7711   tmp = create_tmp_var_raw (type, NULL);
7712
7713   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7714      tree_expr_nonnegative_p giving up immediately.  */
7715   val = last;
7716   if (TREE_CODE (val) == NOP_EXPR
7717       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7718     val = TREE_OPERAND (val, 0);
7719
7720   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7721   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7722
7723   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7724 }
7725
7726 /* Begin the scope of an identifier of variably modified type, scope
7727    number SCOPE.  Jumping from outside this scope to inside it is not
7728    permitted.  */
7729
7730 void
7731 c_begin_vm_scope (unsigned int scope)
7732 {
7733   struct c_label_context_vm *nstack;
7734   struct c_label_list *glist;
7735
7736   gcc_assert (scope > 0);
7737
7738   /* At file_scope, we don't have to do any processing.  */
7739   if (label_context_stack_vm == NULL)
7740     return;
7741
7742   if (c_switch_stack && !c_switch_stack->blocked_vm)
7743     c_switch_stack->blocked_vm = scope;
7744   for (glist = label_context_stack_vm->labels_used;
7745        glist != NULL;
7746        glist = glist->next)
7747     {
7748       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7749     }
7750   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7751   nstack->labels_def = NULL;
7752   nstack->labels_used = NULL;
7753   nstack->scope = scope;
7754   nstack->next = label_context_stack_vm;
7755   label_context_stack_vm = nstack;
7756 }
7757
7758 /* End a scope which may contain identifiers of variably modified
7759    type, scope number SCOPE.  */
7760
7761 void
7762 c_end_vm_scope (unsigned int scope)
7763 {
7764   if (label_context_stack_vm == NULL)
7765     return;
7766   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7767     c_switch_stack->blocked_vm = 0;
7768   /* We may have a number of nested scopes of identifiers with
7769      variably modified type, all at this depth.  Pop each in turn.  */
7770   while (label_context_stack_vm->scope == scope)
7771     {
7772       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7773
7774       /* It is no longer possible to jump to labels defined within this
7775          scope.  */
7776       for (dlist = label_context_stack_vm->labels_def;
7777            dlist != NULL;
7778            dlist = dlist->next)
7779         {
7780           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7781         }
7782       /* It is again possible to define labels with a goto just outside
7783          this scope.  */
7784       for (glist = label_context_stack_vm->next->labels_used;
7785            glist != NULL;
7786            glist = glist->next)
7787         {
7788           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7789           glist_prev = glist;
7790         }
7791       if (glist_prev != NULL)
7792         glist_prev->next = label_context_stack_vm->labels_used;
7793       else
7794         label_context_stack_vm->next->labels_used
7795           = label_context_stack_vm->labels_used;
7796       label_context_stack_vm = label_context_stack_vm->next;
7797     }
7798 }
7799 \f
7800 /* Begin and end compound statements.  This is as simple as pushing
7801    and popping new statement lists from the tree.  */
7802
7803 tree
7804 c_begin_compound_stmt (bool do_scope)
7805 {
7806   tree stmt = push_stmt_list ();
7807   if (do_scope)
7808     push_scope ();
7809   return stmt;
7810 }
7811
7812 tree
7813 c_end_compound_stmt (tree stmt, bool do_scope)
7814 {
7815   tree block = NULL;
7816
7817   if (do_scope)
7818     {
7819       if (c_dialect_objc ())
7820         objc_clear_super_receiver ();
7821       block = pop_scope ();
7822     }
7823
7824   stmt = pop_stmt_list (stmt);
7825   stmt = c_build_bind_expr (block, stmt);
7826
7827   /* If this compound statement is nested immediately inside a statement
7828      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7829      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7830      STATEMENT_LISTs merge, and thus we can lose track of what statement
7831      was really last.  */
7832   if (cur_stmt_list
7833       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7834       && TREE_CODE (stmt) != BIND_EXPR)
7835     {
7836       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7837       TREE_SIDE_EFFECTS (stmt) = 1;
7838     }
7839
7840   return stmt;
7841 }
7842
7843 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7844    when the current scope is exited.  EH_ONLY is true when this is not
7845    meant to apply to normal control flow transfer.  */
7846
7847 void
7848 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7849 {
7850   enum tree_code code;
7851   tree stmt, list;
7852   bool stmt_expr;
7853
7854   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7855   stmt = build_stmt (code, NULL, cleanup);
7856   add_stmt (stmt);
7857   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7858   list = push_stmt_list ();
7859   TREE_OPERAND (stmt, 0) = list;
7860   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7861 }
7862 \f
7863 /* Build a binary-operation expression without default conversions.
7864    CODE is the kind of expression to build.
7865    This function differs from `build' in several ways:
7866    the data type of the result is computed and recorded in it,
7867    warnings are generated if arg data types are invalid,
7868    special handling for addition and subtraction of pointers is known,
7869    and some optimization is done (operations on narrow ints
7870    are done in the narrower type when that gives the same result).
7871    Constant folding is also done before the result is returned.
7872
7873    Note that the operands will never have enumeral types, or function
7874    or array types, because either they will have the default conversions
7875    performed or they have both just been converted to some other type in which
7876    the arithmetic is to be done.  */
7877
7878 tree
7879 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7880                  int convert_p)
7881 {
7882   tree type0, type1;
7883   enum tree_code code0, code1;
7884   tree op0, op1;
7885   const char *invalid_op_diag;
7886
7887   /* Expression code to give to the expression when it is built.
7888      Normally this is CODE, which is what the caller asked for,
7889      but in some special cases we change it.  */
7890   enum tree_code resultcode = code;
7891
7892   /* Data type in which the computation is to be performed.
7893      In the simplest cases this is the common type of the arguments.  */
7894   tree result_type = NULL;
7895
7896   /* Nonzero means operands have already been type-converted
7897      in whatever way is necessary.
7898      Zero means they need to be converted to RESULT_TYPE.  */
7899   int converted = 0;
7900
7901   /* Nonzero means create the expression with this type, rather than
7902      RESULT_TYPE.  */
7903   tree build_type = 0;
7904
7905   /* Nonzero means after finally constructing the expression
7906      convert it to this type.  */
7907   tree final_type = 0;
7908
7909   /* Nonzero if this is an operation like MIN or MAX which can
7910      safely be computed in short if both args are promoted shorts.
7911      Also implies COMMON.
7912      -1 indicates a bitwise operation; this makes a difference
7913      in the exact conditions for when it is safe to do the operation
7914      in a narrower mode.  */
7915   int shorten = 0;
7916
7917   /* Nonzero if this is a comparison operation;
7918      if both args are promoted shorts, compare the original shorts.
7919      Also implies COMMON.  */
7920   int short_compare = 0;
7921
7922   /* Nonzero if this is a right-shift operation, which can be computed on the
7923      original short and then promoted if the operand is a promoted short.  */
7924   int short_shift = 0;
7925
7926   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7927   int common = 0;
7928
7929   /* True means types are compatible as far as ObjC is concerned.  */
7930   bool objc_ok;
7931
7932   if (convert_p)
7933     {
7934       op0 = default_conversion (orig_op0);
7935       op1 = default_conversion (orig_op1);
7936     }
7937   else
7938     {
7939       op0 = orig_op0;
7940       op1 = orig_op1;
7941     }
7942
7943   type0 = TREE_TYPE (op0);
7944   type1 = TREE_TYPE (op1);
7945
7946   /* The expression codes of the data types of the arguments tell us
7947      whether the arguments are integers, floating, pointers, etc.  */
7948   code0 = TREE_CODE (type0);
7949   code1 = TREE_CODE (type1);
7950
7951   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7952   STRIP_TYPE_NOPS (op0);
7953   STRIP_TYPE_NOPS (op1);
7954
7955   /* If an error was already reported for one of the arguments,
7956      avoid reporting another error.  */
7957
7958   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7959     return error_mark_node;
7960
7961   if ((invalid_op_diag
7962        = targetm.invalid_binary_op (code, type0, type1)))
7963     {
7964       error (invalid_op_diag);
7965       return error_mark_node;
7966     }
7967
7968   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7969
7970   switch (code)
7971     {
7972     case PLUS_EXPR:
7973       /* Handle the pointer + int case.  */
7974       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7975         return pointer_int_sum (PLUS_EXPR, op0, op1);
7976       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7977         return pointer_int_sum (PLUS_EXPR, op1, op0);
7978       else
7979         common = 1;
7980       break;
7981
7982     case MINUS_EXPR:
7983       /* Subtraction of two similar pointers.
7984          We must subtract them as integers, then divide by object size.  */
7985       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7986           && comp_target_types (type0, type1))
7987         return pointer_diff (op0, op1);
7988       /* Handle pointer minus int.  Just like pointer plus int.  */
7989       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7990         return pointer_int_sum (MINUS_EXPR, op0, op1);
7991       else
7992         common = 1;
7993       break;
7994
7995     case MULT_EXPR:
7996       common = 1;
7997       break;
7998
7999     case TRUNC_DIV_EXPR:
8000     case CEIL_DIV_EXPR:
8001     case FLOOR_DIV_EXPR:
8002     case ROUND_DIV_EXPR:
8003     case EXACT_DIV_EXPR:
8004       warn_for_div_by_zero (op1);
8005
8006       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8007            || code0 == FIXED_POINT_TYPE
8008            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8009           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8010               || code1 == FIXED_POINT_TYPE
8011               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8012         {
8013           enum tree_code tcode0 = code0, tcode1 = code1;
8014
8015           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8016             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8017           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8018             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8019
8020           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8021               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8022             resultcode = RDIV_EXPR;
8023           else
8024             /* Although it would be tempting to shorten always here, that
8025                loses on some targets, since the modulo instruction is
8026                undefined if the quotient can't be represented in the
8027                computation mode.  We shorten only if unsigned or if
8028                dividing by something we know != -1.  */
8029             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8030                        || (TREE_CODE (op1) == INTEGER_CST
8031                            && !integer_all_onesp (op1)));
8032           common = 1;
8033         }
8034       break;
8035
8036     case BIT_AND_EXPR:
8037     case BIT_IOR_EXPR:
8038     case BIT_XOR_EXPR:
8039       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8040         shorten = -1;
8041       /* Allow vector types which are not floating point types.   */
8042       else if (code0 == VECTOR_TYPE
8043                && code1 == VECTOR_TYPE
8044                && !VECTOR_FLOAT_TYPE_P (type0)
8045                && !VECTOR_FLOAT_TYPE_P (type1))
8046         common = 1;
8047       break;
8048
8049     case TRUNC_MOD_EXPR:
8050     case FLOOR_MOD_EXPR:
8051       warn_for_div_by_zero (op1);
8052
8053       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8054         {
8055           /* Although it would be tempting to shorten always here, that loses
8056              on some targets, since the modulo instruction is undefined if the
8057              quotient can't be represented in the computation mode.  We shorten
8058              only if unsigned or if dividing by something we know != -1.  */
8059           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8060                      || (TREE_CODE (op1) == INTEGER_CST
8061                          && !integer_all_onesp (op1)));
8062           common = 1;
8063         }
8064       break;
8065
8066     case TRUTH_ANDIF_EXPR:
8067     case TRUTH_ORIF_EXPR:
8068     case TRUTH_AND_EXPR:
8069     case TRUTH_OR_EXPR:
8070     case TRUTH_XOR_EXPR:
8071       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8072            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8073            || code0 == FIXED_POINT_TYPE)
8074           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8075               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8076               || code1 == FIXED_POINT_TYPE))
8077         {
8078           /* Result of these operations is always an int,
8079              but that does not mean the operands should be
8080              converted to ints!  */
8081           result_type = integer_type_node;
8082           op0 = c_common_truthvalue_conversion (op0);
8083           op1 = c_common_truthvalue_conversion (op1);
8084           converted = 1;
8085         }
8086       break;
8087
8088       /* Shift operations: result has same type as first operand;
8089          always convert second operand to int.
8090          Also set SHORT_SHIFT if shifting rightward.  */
8091
8092     case RSHIFT_EXPR:
8093       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8094           && code1 == INTEGER_TYPE)
8095         {
8096           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8097             {
8098               if (tree_int_cst_sgn (op1) < 0)
8099                 warning (0, "right shift count is negative");
8100               else
8101                 {
8102                   if (!integer_zerop (op1))
8103                     short_shift = 1;
8104
8105                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8106                     warning (0, "right shift count >= width of type");
8107                 }
8108             }
8109
8110           /* Use the type of the value to be shifted.  */
8111           result_type = type0;
8112           /* Convert the shift-count to an integer, regardless of size
8113              of value being shifted.  */
8114           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8115             op1 = convert (integer_type_node, op1);
8116           /* Avoid converting op1 to result_type later.  */
8117           converted = 1;
8118         }
8119       break;
8120
8121     case LSHIFT_EXPR:
8122       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8123           && code1 == INTEGER_TYPE)
8124         {
8125           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8126             {
8127               if (tree_int_cst_sgn (op1) < 0)
8128                 warning (0, "left shift count is negative");
8129
8130               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8131                 warning (0, "left shift count >= width of type");
8132             }
8133
8134           /* Use the type of the value to be shifted.  */
8135           result_type = type0;
8136           /* Convert the shift-count to an integer, regardless of size
8137              of value being shifted.  */
8138           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8139             op1 = convert (integer_type_node, op1);
8140           /* Avoid converting op1 to result_type later.  */
8141           converted = 1;
8142         }
8143       break;
8144
8145     case EQ_EXPR:
8146     case NE_EXPR:
8147       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8148         warning (OPT_Wfloat_equal,
8149                  "comparing floating point with == or != is unsafe");
8150       /* Result of comparison is always int,
8151          but don't convert the args to int!  */
8152       build_type = integer_type_node;
8153       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8154            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8155           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8156               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8157         short_compare = 1;
8158       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8159         {
8160           tree tt0 = TREE_TYPE (type0);
8161           tree tt1 = TREE_TYPE (type1);
8162           /* Anything compares with void *.  void * compares with anything.
8163              Otherwise, the targets must be compatible
8164              and both must be object or both incomplete.  */
8165           if (comp_target_types (type0, type1))
8166             result_type = common_pointer_type (type0, type1);
8167           else if (VOID_TYPE_P (tt0))
8168             {
8169               /* op0 != orig_op0 detects the case of something
8170                  whose value is 0 but which isn't a valid null ptr const.  */
8171               if (pedantic && !null_pointer_constant_p (orig_op0)
8172                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8173                 pedwarn ("ISO C forbids comparison of %<void *%>"
8174                          " with function pointer");
8175             }
8176           else if (VOID_TYPE_P (tt1))
8177             {
8178               if (pedantic && !null_pointer_constant_p (orig_op1)
8179                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8180                 pedwarn ("ISO C forbids comparison of %<void *%>"
8181                          " with function pointer");
8182             }
8183           else
8184             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8185             if (!objc_ok)
8186               pedwarn ("comparison of distinct pointer types lacks a cast");
8187
8188           if (result_type == NULL_TREE)
8189             result_type = ptr_type_node;
8190         }
8191       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8192         {
8193           if (TREE_CODE (op0) == ADDR_EXPR
8194               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8195             warning (OPT_Waddress, "the address of %qD will never be NULL",
8196                      TREE_OPERAND (op0, 0));
8197           result_type = type0;
8198         }
8199       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8200         {
8201           if (TREE_CODE (op1) == ADDR_EXPR
8202               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8203             warning (OPT_Waddress, "the address of %qD will never be NULL",
8204                      TREE_OPERAND (op1, 0));
8205           result_type = type1;
8206         }
8207       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8208         {
8209           result_type = type0;
8210           pedwarn ("comparison between pointer and integer");
8211         }
8212       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8213         {
8214           result_type = type1;
8215           pedwarn ("comparison between pointer and integer");
8216         }
8217       break;
8218
8219     case LE_EXPR:
8220     case GE_EXPR:
8221     case LT_EXPR:
8222     case GT_EXPR:
8223       build_type = integer_type_node;
8224       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8225            || code0 == FIXED_POINT_TYPE)
8226           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8227               || code1 == FIXED_POINT_TYPE))
8228         short_compare = 1;
8229       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8230         {
8231           if (comp_target_types (type0, type1))
8232             {
8233               result_type = common_pointer_type (type0, type1);
8234               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8235                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8236                 pedwarn ("comparison of complete and incomplete pointers");
8237               else if (pedantic
8238                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8239                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8240             }
8241           else
8242             {
8243               result_type = ptr_type_node;
8244               pedwarn ("comparison of distinct pointer types lacks a cast");
8245             }
8246         }
8247       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8248         {
8249           result_type = type0;
8250           if (pedantic || extra_warnings)
8251             pedwarn ("ordered comparison of pointer with integer zero");
8252         }
8253       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8254         {
8255           result_type = type1;
8256           if (pedantic)
8257             pedwarn ("ordered comparison of pointer with integer zero");
8258         }
8259       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8260         {
8261           result_type = type0;
8262           pedwarn ("comparison between pointer and integer");
8263         }
8264       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8265         {
8266           result_type = type1;
8267           pedwarn ("comparison between pointer and integer");
8268         }
8269       break;
8270
8271     default:
8272       gcc_unreachable ();
8273     }
8274
8275   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8276     return error_mark_node;
8277
8278   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8279       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8280           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8281                                                     TREE_TYPE (type1))))
8282     {
8283       binary_op_error (code, type0, type1);
8284       return error_mark_node;
8285     }
8286
8287   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8288        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8289       &&
8290       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8291        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8292     {
8293       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8294
8295       if (shorten || common || short_compare)
8296         {
8297           result_type = c_common_type (type0, type1);
8298           if (result_type == error_mark_node)
8299             return error_mark_node;
8300         }
8301
8302       /* For certain operations (which identify themselves by shorten != 0)
8303          if both args were extended from the same smaller type,
8304          do the arithmetic in that type and then extend.
8305
8306          shorten !=0 and !=1 indicates a bitwise operation.
8307          For them, this optimization is safe only if
8308          both args are zero-extended or both are sign-extended.
8309          Otherwise, we might change the result.
8310          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8311          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8312
8313       if (shorten && none_complex)
8314         {
8315           int unsigned0, unsigned1;
8316           tree arg0, arg1;
8317           int uns;
8318           tree type;
8319
8320           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8321              excessive narrowing when we call get_narrower below.  For
8322              example, suppose that OP0 is of unsigned int extended
8323              from signed char and that RESULT_TYPE is long long int.
8324              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8325              like
8326
8327                (long long int) (unsigned int) signed_char
8328
8329              which get_narrower would narrow down to
8330
8331                (unsigned int) signed char
8332
8333              If we do not cast OP0 first, get_narrower would return
8334              signed_char, which is inconsistent with the case of the
8335              explicit cast.  */
8336           op0 = convert (result_type, op0);
8337           op1 = convert (result_type, op1);
8338
8339           arg0 = get_narrower (op0, &unsigned0);
8340           arg1 = get_narrower (op1, &unsigned1);
8341
8342           /* UNS is 1 if the operation to be done is an unsigned one.  */
8343           uns = TYPE_UNSIGNED (result_type);
8344
8345           final_type = result_type;
8346
8347           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8348              but it *requires* conversion to FINAL_TYPE.  */
8349
8350           if ((TYPE_PRECISION (TREE_TYPE (op0))
8351                == TYPE_PRECISION (TREE_TYPE (arg0)))
8352               && TREE_TYPE (op0) != final_type)
8353             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8354           if ((TYPE_PRECISION (TREE_TYPE (op1))
8355                == TYPE_PRECISION (TREE_TYPE (arg1)))
8356               && TREE_TYPE (op1) != final_type)
8357             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8358
8359           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8360
8361           /* For bitwise operations, signedness of nominal type
8362              does not matter.  Consider only how operands were extended.  */
8363           if (shorten == -1)
8364             uns = unsigned0;
8365
8366           /* Note that in all three cases below we refrain from optimizing
8367              an unsigned operation on sign-extended args.
8368              That would not be valid.  */
8369
8370           /* Both args variable: if both extended in same way
8371              from same width, do it in that width.
8372              Do it unsigned if args were zero-extended.  */
8373           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8374                < TYPE_PRECISION (result_type))
8375               && (TYPE_PRECISION (TREE_TYPE (arg1))
8376                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8377               && unsigned0 == unsigned1
8378               && (unsigned0 || !uns))
8379             result_type
8380               = c_common_signed_or_unsigned_type
8381               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8382           else if (TREE_CODE (arg0) == INTEGER_CST
8383                    && (unsigned1 || !uns)
8384                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8385                        < TYPE_PRECISION (result_type))
8386                    && (type
8387                        = c_common_signed_or_unsigned_type (unsigned1,
8388                                                            TREE_TYPE (arg1)))
8389                    && !POINTER_TYPE_P (type)
8390                    && int_fits_type_p (arg0, type))
8391             result_type = type;
8392           else if (TREE_CODE (arg1) == INTEGER_CST
8393                    && (unsigned0 || !uns)
8394                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8395                        < TYPE_PRECISION (result_type))
8396                    && (type
8397                        = c_common_signed_or_unsigned_type (unsigned0,
8398                                                            TREE_TYPE (arg0)))
8399                    && !POINTER_TYPE_P (type)
8400                    && int_fits_type_p (arg1, type))
8401             result_type = type;
8402         }
8403
8404       /* Shifts can be shortened if shifting right.  */
8405
8406       if (short_shift)
8407         {
8408           int unsigned_arg;
8409           tree arg0 = get_narrower (op0, &unsigned_arg);
8410
8411           final_type = result_type;
8412
8413           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8414             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8415
8416           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8417               /* We can shorten only if the shift count is less than the
8418                  number of bits in the smaller type size.  */
8419               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8420               /* We cannot drop an unsigned shift after sign-extension.  */
8421               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8422             {
8423               /* Do an unsigned shift if the operand was zero-extended.  */
8424               result_type
8425                 = c_common_signed_or_unsigned_type (unsigned_arg,
8426                                                     TREE_TYPE (arg0));
8427               /* Convert value-to-be-shifted to that type.  */
8428               if (TREE_TYPE (op0) != result_type)
8429                 op0 = convert (result_type, op0);
8430               converted = 1;
8431             }
8432         }
8433
8434       /* Comparison operations are shortened too but differently.
8435          They identify themselves by setting short_compare = 1.  */
8436
8437       if (short_compare)
8438         {
8439           /* Don't write &op0, etc., because that would prevent op0
8440              from being kept in a register.
8441              Instead, make copies of the our local variables and
8442              pass the copies by reference, then copy them back afterward.  */
8443           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8444           enum tree_code xresultcode = resultcode;
8445           tree val
8446             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8447
8448           if (val != 0)
8449             return val;
8450
8451           op0 = xop0, op1 = xop1;
8452           converted = 1;
8453           resultcode = xresultcode;
8454
8455           if (warn_sign_compare && skip_evaluation == 0)
8456             {
8457               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8458               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8459               int unsignedp0, unsignedp1;
8460               tree primop0 = get_narrower (op0, &unsignedp0);
8461               tree primop1 = get_narrower (op1, &unsignedp1);
8462
8463               xop0 = orig_op0;
8464               xop1 = orig_op1;
8465               STRIP_TYPE_NOPS (xop0);
8466               STRIP_TYPE_NOPS (xop1);
8467
8468               /* Give warnings for comparisons between signed and unsigned
8469                  quantities that may fail.
8470
8471                  Do the checking based on the original operand trees, so that
8472                  casts will be considered, but default promotions won't be.
8473
8474                  Do not warn if the comparison is being done in a signed type,
8475                  since the signed type will only be chosen if it can represent
8476                  all the values of the unsigned type.  */
8477               if (!TYPE_UNSIGNED (result_type))
8478                 /* OK */;
8479               /* Do not warn if both operands are the same signedness.  */
8480               else if (op0_signed == op1_signed)
8481                 /* OK */;
8482               else
8483                 {
8484                   tree sop, uop;
8485                   bool ovf;
8486
8487                   if (op0_signed)
8488                     sop = xop0, uop = xop1;
8489                   else
8490                     sop = xop1, uop = xop0;
8491
8492                   /* Do not warn if the signed quantity is an
8493                      unsuffixed integer literal (or some static
8494                      constant expression involving such literals or a
8495                      conditional expression involving such literals)
8496                      and it is non-negative.  */
8497                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8498                     /* OK */;
8499                   /* Do not warn if the comparison is an equality operation,
8500                      the unsigned quantity is an integral constant, and it
8501                      would fit in the result if the result were signed.  */
8502                   else if (TREE_CODE (uop) == INTEGER_CST
8503                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8504                            && int_fits_type_p
8505                            (uop, c_common_signed_type (result_type)))
8506                     /* OK */;
8507                   /* Do not warn if the unsigned quantity is an enumeration
8508                      constant and its maximum value would fit in the result
8509                      if the result were signed.  */
8510                   else if (TREE_CODE (uop) == INTEGER_CST
8511                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8512                            && int_fits_type_p
8513                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8514                             c_common_signed_type (result_type)))
8515                     /* OK */;
8516                   else
8517                     warning (OPT_Wsign_compare, "comparison between signed and unsigned");
8518                 }
8519
8520               /* Warn if two unsigned values are being compared in a size
8521                  larger than their original size, and one (and only one) is the
8522                  result of a `~' operator.  This comparison will always fail.
8523
8524                  Also warn if one operand is a constant, and the constant
8525                  does not have all bits set that are set in the ~ operand
8526                  when it is extended.  */
8527
8528               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8529                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8530                 {
8531                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8532                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8533                                             &unsignedp0);
8534                   else
8535                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8536                                             &unsignedp1);
8537
8538                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8539                     {
8540                       tree primop;
8541                       HOST_WIDE_INT constant, mask;
8542                       int unsignedp, bits;
8543
8544                       if (host_integerp (primop0, 0))
8545                         {
8546                           primop = primop1;
8547                           unsignedp = unsignedp1;
8548                           constant = tree_low_cst (primop0, 0);
8549                         }
8550                       else
8551                         {
8552                           primop = primop0;
8553                           unsignedp = unsignedp0;
8554                           constant = tree_low_cst (primop1, 0);
8555                         }
8556
8557                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8558                       if (bits < TYPE_PRECISION (result_type)
8559                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8560                         {
8561                           mask = (~(HOST_WIDE_INT) 0) << bits;
8562                           if ((mask & constant) != mask)
8563                             warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with constant");
8564                         }
8565                     }
8566                   else if (unsignedp0 && unsignedp1
8567                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8568                                < TYPE_PRECISION (result_type))
8569                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8570                                < TYPE_PRECISION (result_type)))
8571                     warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with unsigned");
8572                 }
8573             }
8574         }
8575     }
8576
8577   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8578      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8579      Then the expression will be built.
8580      It will be given type FINAL_TYPE if that is nonzero;
8581      otherwise, it will be given type RESULT_TYPE.  */
8582
8583   if (!result_type)
8584     {
8585       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8586       return error_mark_node;
8587     }
8588
8589   if (!converted)
8590     {
8591       if (TREE_TYPE (op0) != result_type)
8592         op0 = convert_and_check (result_type, op0);
8593       if (TREE_TYPE (op1) != result_type)
8594         op1 = convert_and_check (result_type, op1);
8595
8596       /* This can happen if one operand has a vector type, and the other
8597          has a different type.  */
8598       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8599         return error_mark_node;
8600     }
8601
8602   if (build_type == NULL_TREE)
8603     build_type = result_type;
8604
8605   {
8606     /* Treat expressions in initializers specially as they can't trap.  */
8607     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8608                                                                     build_type,
8609                                                                     op0, op1)
8610                                          : fold_build2 (resultcode, build_type,
8611                                                         op0, op1);
8612
8613     if (final_type != 0)
8614       result = convert (final_type, result);
8615     return result;
8616   }
8617 }
8618
8619
8620 /* Convert EXPR to be a truth-value, validating its type for this
8621    purpose.  */
8622
8623 tree
8624 c_objc_common_truthvalue_conversion (tree expr)
8625 {
8626   switch (TREE_CODE (TREE_TYPE (expr)))
8627     {
8628     case ARRAY_TYPE:
8629       error ("used array that cannot be converted to pointer where scalar is required");
8630       return error_mark_node;
8631
8632     case RECORD_TYPE:
8633       error ("used struct type value where scalar is required");
8634       return error_mark_node;
8635
8636     case UNION_TYPE:
8637       error ("used union type value where scalar is required");
8638       return error_mark_node;
8639
8640     case FUNCTION_TYPE:
8641       gcc_unreachable ();
8642
8643     default:
8644       break;
8645     }
8646
8647   /* ??? Should we also give an error for void and vectors rather than
8648      leaving those to give errors later?  */
8649   return c_common_truthvalue_conversion (expr);
8650 }
8651 \f
8652
8653 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8654    required.  */
8655
8656 tree
8657 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8658                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8659 {
8660   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8661     {
8662       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8663       /* Executing a compound literal inside a function reinitializes
8664          it.  */
8665       if (!TREE_STATIC (decl))
8666         *se = true;
8667       return decl;
8668     }
8669   else
8670     return expr;
8671 }
8672 \f
8673 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8674
8675 tree
8676 c_begin_omp_parallel (void)
8677 {
8678   tree block;
8679
8680   keep_next_level ();
8681   block = c_begin_compound_stmt (true);
8682
8683   return block;
8684 }
8685
8686 tree
8687 c_finish_omp_parallel (tree clauses, tree block)
8688 {
8689   tree stmt;
8690
8691   block = c_end_compound_stmt (block, true);
8692
8693   stmt = make_node (OMP_PARALLEL);
8694   TREE_TYPE (stmt) = void_type_node;
8695   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8696   OMP_PARALLEL_BODY (stmt) = block;
8697
8698   return add_stmt (stmt);
8699 }
8700
8701 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8702    Remove any elements from the list that are invalid.  */
8703
8704 tree
8705 c_finish_omp_clauses (tree clauses)
8706 {
8707   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8708   tree c, t, *pc = &clauses;
8709   const char *name;
8710
8711   bitmap_obstack_initialize (NULL);
8712   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8713   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8714   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8715
8716   for (pc = &clauses, c = clauses; c ; c = *pc)
8717     {
8718       bool remove = false;
8719       bool need_complete = false;
8720       bool need_implicitly_determined = false;
8721
8722       switch (OMP_CLAUSE_CODE (c))
8723         {
8724         case OMP_CLAUSE_SHARED:
8725           name = "shared";
8726           need_implicitly_determined = true;
8727           goto check_dup_generic;
8728
8729         case OMP_CLAUSE_PRIVATE:
8730           name = "private";
8731           need_complete = true;
8732           need_implicitly_determined = true;
8733           goto check_dup_generic;
8734
8735         case OMP_CLAUSE_REDUCTION:
8736           name = "reduction";
8737           need_implicitly_determined = true;
8738           t = OMP_CLAUSE_DECL (c);
8739           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8740               || POINTER_TYPE_P (TREE_TYPE (t)))
8741             {
8742               error ("%qE has invalid type for %<reduction%>", t);
8743               remove = true;
8744             }
8745           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8746             {
8747               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8748               const char *r_name = NULL;
8749
8750               switch (r_code)
8751                 {
8752                 case PLUS_EXPR:
8753                 case MULT_EXPR:
8754                 case MINUS_EXPR:
8755                   break;
8756                 case BIT_AND_EXPR:
8757                   r_name = "&";
8758                   break;
8759                 case BIT_XOR_EXPR:
8760                   r_name = "^";
8761                   break;
8762                 case BIT_IOR_EXPR:
8763                   r_name = "|";
8764                   break;
8765                 case TRUTH_ANDIF_EXPR:
8766                   r_name = "&&";
8767                   break;
8768                 case TRUTH_ORIF_EXPR:
8769                   r_name = "||";
8770                   break;
8771                 default:
8772                   gcc_unreachable ();
8773                 }
8774               if (r_name)
8775                 {
8776                   error ("%qE has invalid type for %<reduction(%s)%>",
8777                          t, r_name);
8778                   remove = true;
8779                 }
8780             }
8781           goto check_dup_generic;
8782
8783         case OMP_CLAUSE_COPYPRIVATE:
8784           name = "copyprivate";
8785           goto check_dup_generic;
8786
8787         case OMP_CLAUSE_COPYIN:
8788           name = "copyin";
8789           t = OMP_CLAUSE_DECL (c);
8790           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8791             {
8792               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8793               remove = true;
8794             }
8795           goto check_dup_generic;
8796
8797         check_dup_generic:
8798           t = OMP_CLAUSE_DECL (c);
8799           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8800             {
8801               error ("%qE is not a variable in clause %qs", t, name);
8802               remove = true;
8803             }
8804           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8805                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8806                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8807             {
8808               error ("%qE appears more than once in data clauses", t);
8809               remove = true;
8810             }
8811           else
8812             bitmap_set_bit (&generic_head, DECL_UID (t));
8813           break;
8814
8815         case OMP_CLAUSE_FIRSTPRIVATE:
8816           name = "firstprivate";
8817           t = OMP_CLAUSE_DECL (c);
8818           need_complete = true;
8819           need_implicitly_determined = true;
8820           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8821             {
8822               error ("%qE is not a variable in clause %<firstprivate%>", t);
8823               remove = true;
8824             }
8825           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8826                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8827             {
8828               error ("%qE appears more than once in data clauses", t);
8829               remove = true;
8830             }
8831           else
8832             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8833           break;
8834
8835         case OMP_CLAUSE_LASTPRIVATE:
8836           name = "lastprivate";
8837           t = OMP_CLAUSE_DECL (c);
8838           need_complete = true;
8839           need_implicitly_determined = true;
8840           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8841             {
8842               error ("%qE is not a variable in clause %<lastprivate%>", t);
8843               remove = true;
8844             }
8845           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8846                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8847             {
8848               error ("%qE appears more than once in data clauses", t);
8849               remove = true;
8850             }
8851           else
8852             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8853           break;
8854
8855         case OMP_CLAUSE_IF:
8856         case OMP_CLAUSE_NUM_THREADS:
8857         case OMP_CLAUSE_SCHEDULE:
8858         case OMP_CLAUSE_NOWAIT:
8859         case OMP_CLAUSE_ORDERED:
8860         case OMP_CLAUSE_DEFAULT:
8861           pc = &OMP_CLAUSE_CHAIN (c);
8862           continue;
8863
8864         default:
8865           gcc_unreachable ();
8866         }
8867
8868       if (!remove)
8869         {
8870           t = OMP_CLAUSE_DECL (c);
8871
8872           if (need_complete)
8873             {
8874               t = require_complete_type (t);
8875               if (t == error_mark_node)
8876                 remove = true;
8877             }
8878
8879           if (need_implicitly_determined)
8880             {
8881               const char *share_name = NULL;
8882
8883               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8884                 share_name = "threadprivate";
8885               else switch (c_omp_predetermined_sharing (t))
8886                 {
8887                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8888                   break;
8889                 case OMP_CLAUSE_DEFAULT_SHARED:
8890                   share_name = "shared";
8891                   break;
8892                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8893                   share_name = "private";
8894                   break;
8895                 default:
8896                   gcc_unreachable ();
8897                 }
8898               if (share_name)
8899                 {
8900                   error ("%qE is predetermined %qs for %qs",
8901                          t, share_name, name);
8902                   remove = true;
8903                 }
8904             }
8905         }
8906
8907       if (remove)
8908         *pc = OMP_CLAUSE_CHAIN (c);
8909       else
8910         pc = &OMP_CLAUSE_CHAIN (c);
8911     }
8912
8913   bitmap_obstack_release (NULL);
8914   return clauses;
8915 }
8916
8917 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8918    down to the element type of an array.  */
8919
8920 tree
8921 c_build_qualified_type (tree type, int type_quals)
8922 {
8923   if (type == error_mark_node)
8924     return type;
8925
8926   if (TREE_CODE (type) == ARRAY_TYPE)
8927     {
8928       tree t;
8929       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8930                                                   type_quals);
8931
8932       /* See if we already have an identically qualified type.  */
8933       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8934         {
8935           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8936               && TYPE_NAME (t) == TYPE_NAME (type)
8937               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8938               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8939                                        TYPE_ATTRIBUTES (type)))
8940             break;
8941         }
8942       if (!t)
8943         {
8944           tree domain = TYPE_DOMAIN (type);
8945
8946           t = build_variant_type_copy (type);
8947           TREE_TYPE (t) = element_type;
8948
8949           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8950               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8951             SET_TYPE_STRUCTURAL_EQUALITY (t);
8952           else if (TYPE_CANONICAL (element_type) != element_type
8953                    || (domain && TYPE_CANONICAL (domain) != domain))
8954             {
8955               tree unqualified_canon
8956                 = build_array_type (TYPE_CANONICAL (element_type),
8957                                     domain? TYPE_CANONICAL (domain)
8958                                           : NULL_TREE);
8959               TYPE_CANONICAL (t)
8960                 = c_build_qualified_type (unqualified_canon, type_quals);
8961             }
8962           else
8963             TYPE_CANONICAL (t) = t;
8964         }
8965       return t;
8966     }
8967
8968   /* A restrict-qualified pointer type must be a pointer to object or
8969      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8970      REFERENCE_TYPEs, which is appropriate for C++.  */
8971   if ((type_quals & TYPE_QUAL_RESTRICT)
8972       && (!POINTER_TYPE_P (type)
8973           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8974     {
8975       error ("invalid use of %<restrict%>");
8976       type_quals &= ~TYPE_QUAL_RESTRICT;
8977     }
8978
8979   return build_qualified_type (type, type_quals);
8980 }