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,
   3    1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  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
  47
  48 /* Nonzero if we've already printed a "missing braces around initializer"
  49    message within this initializer.  */
  50 static int missing_braces_mentioned;
  51
  52 static int require_constant_value;
  53 static int require_constant_elements;
  54
  55 static tree qualify_type (tree, tree);
  56 static int tagged_types_tu_compatible_p (tree, tree);
  57 static int comp_target_types (tree, tree, int);
  58 static int function_types_compatible_p (tree, tree);
  59 static int type_lists_compatible_p (tree, tree);
  60 static tree decl_constant_value_for_broken_optimization (tree);
  61 static tree default_function_array_conversion (tree);
  62 static tree lookup_field (tree, tree);
  63 static tree convert_arguments (tree, tree, tree, tree);
  64 static tree pointer_diff (tree, tree);
  65 static tree convert_for_assignment (tree, tree, const char *, tree, tree,
  66                                     int);
  67 static void warn_for_assignment (const char *, const char *, tree, int);
  68 static tree valid_compound_expr_initializer (tree, tree);
  69 static void push_string (const char *);
  70 static void push_member_name (tree);
  71 static void push_array_bounds (int);
  72 static int spelling_length (void);
  73 static char *print_spelling (char *);
  74 static void warning_init (const char *);
  75 static tree digest_init (tree, tree, bool, int);
  76 static void output_init_element (tree, bool, tree, tree, int);
  77 static void output_pending_init_elements (int);
  78 static int set_designator (int);
  79 static void push_range_stack (tree);
  80 static void add_pending_init (tree, tree);
  81 static void set_nonincremental_init (void);
  82 static void set_nonincremental_init_from_string (tree);
  83 static tree find_init_member (tree);
  84 static int lvalue_or_else (tree, const char *);
  85 \f
  86 /* Do `exp = require_complete_type (exp);' to make sure exp
  87    does not have an incomplete type.  (That includes void types.)  */
  88
  89 tree
  90 require_complete_type (tree value)
  91 {
  92   tree type = TREE_TYPE (value);
  93
  94   if (value == error_mark_node || type == error_mark_node)
  95     return error_mark_node;
  96
  97   /* First, detect a valid value with a complete type.  */
  98   if (COMPLETE_TYPE_P (type))
  99     return value;
 100
 101   c_incomplete_type_error (value, type);
 102   return error_mark_node;
 103 }
 104
 105 /* Print an error message for invalid use of an incomplete type.
 106    VALUE is the expression that was used (or 0 if that isn't known)
 107    and TYPE is the type that was invalid.  */
 108
 109 void
 110 c_incomplete_type_error (tree value, tree type)
 111 {
 112   const char *type_code_string;
 113
 114   /* Avoid duplicate error message.  */
 115   if (TREE_CODE (type) == ERROR_MARK)
 116     return;
 117
 118   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 119                      || TREE_CODE (value) == PARM_DECL))
 120     error ("`%s' has an incomplete type",
 121            IDENTIFIER_POINTER (DECL_NAME (value)));
 122   else
 123     {
 124     retry:
 125       /* We must print an error message.  Be clever about what it says.  */
 126
 127       switch (TREE_CODE (type))
 128         {
 129         case RECORD_TYPE:
 130           type_code_string = "struct";
 131           break;
 132
 133         case UNION_TYPE:
 134           type_code_string = "union";
 135           break;
 136
 137         case ENUMERAL_TYPE:
 138           type_code_string = "enum";
 139           break;
 140
 141         case VOID_TYPE:
 142           error ("invalid use of void expression");
 143           return;
 144
 145         case ARRAY_TYPE:
 146           if (TYPE_DOMAIN (type))
 147             {
 148               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 149                 {
 150                   error ("invalid use of flexible array member");
 151                   return;
 152                 }
 153               type = TREE_TYPE (type);
 154               goto retry;
 155             }
 156           error ("invalid use of array with unspecified bounds");
 157           return;
 158
 159         default:
 160           abort ();
 161         }
 162
 163       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 164         error ("invalid use of undefined type `%s %s'",
 165                type_code_string, IDENTIFIER_POINTER (TYPE_NAME (type)));
 166       else
 167         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 168         error ("invalid use of incomplete typedef `%s'",
 169                IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
 170     }
 171 }
 172
 173 /* Given a type, apply default promotions wrt unnamed function
 174    arguments and return the new type.  */
 175
 176 tree
 177 c_type_promotes_to (tree type)
 178 {
 179   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 180     return double_type_node;
 181
 182   if (c_promoting_integer_type_p (type))
 183     {
 184       /* Preserve unsignedness if not really getting any wider.  */
 185       if (TYPE_UNSIGNED (type)
 186           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 187         return unsigned_type_node;
 188       return integer_type_node;
 189     }
 190
 191   return type;
 192 }
 193
 194 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 195    as well as those of TYPE.  */
 196
 197 static tree
 198 qualify_type (tree type, tree like)
 199 {
 200   return c_build_qualified_type (type,
 201                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 202 }
 203 \f
 204 /* Return the composite type of two compatible types.
 205
 206    We assume that comptypes has already been done and returned
 207    nonzero; if that isn't so, this may crash.  In particular, we
 208    assume that qualifiers match.  */
 209
 210 tree
 211 composite_type (tree t1, tree t2)
 212 {
 213   enum tree_code code1;
 214   enum tree_code code2;
 215   tree attributes;
 216
 217   /* Save time if the two types are the same.  */
 218
 219   if (t1 == t2) return t1;
 220
 221   /* If one type is nonsense, use the other.  */
 222   if (t1 == error_mark_node)
 223     return t2;
 224   if (t2 == error_mark_node)
 225     return t1;
 226
 227   code1 = TREE_CODE (t1);
 228   code2 = TREE_CODE (t2);
 229
 230   /* Merge the attributes.  */
 231   attributes = targetm.merge_type_attributes (t1, t2);
 232
 233   /* If one is an enumerated type and the other is the compatible
 234      integer type, the composite type might be either of the two
 235      (DR#013 question 3).  For consistency, use the enumerated type as
 236      the composite type.  */
 237
 238   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 239     return t1;
 240   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 241     return t2;
 242
 243   if (code1 != code2)
 244     abort ();
 245
 246   switch (code1)
 247     {
 248     case POINTER_TYPE:
 249       /* For two pointers, do this recursively on the target type.  */
 250       {
 251         tree pointed_to_1 = TREE_TYPE (t1);
 252         tree pointed_to_2 = TREE_TYPE (t2);
 253         tree target = composite_type (pointed_to_1, pointed_to_2);
 254         t1 = build_pointer_type (target);
 255         t1 = build_type_attribute_variant (t1, attributes);
 256         return qualify_type (t1, t2);
 257       }
 258
 259     case ARRAY_TYPE:
 260       {
 261         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 262
 263         /* We should not have any type quals on arrays at all.  */
 264         if (TYPE_QUALS (t1) || TYPE_QUALS (t2))
 265           abort ();
 266
 267         /* Save space: see if the result is identical to one of the args.  */
 268         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
 269           return build_type_attribute_variant (t1, attributes);
 270         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
 271           return build_type_attribute_variant (t2, attributes);
 272
 273         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 274           return build_type_attribute_variant (t1, attributes);
 275         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 276           return build_type_attribute_variant (t2, attributes);
 277
 278         /* Merge the element types, and have a size if either arg has one.  */
 279         t1 = build_array_type (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
 280         return build_type_attribute_variant (t1, attributes);
 281       }
 282
 283     case FUNCTION_TYPE:
 284       /* Function types: prefer the one that specified arg types.
 285          If both do, merge the arg types.  Also merge the return types.  */
 286       {
 287         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 288         tree p1 = TYPE_ARG_TYPES (t1);
 289         tree p2 = TYPE_ARG_TYPES (t2);
 290         int len;
 291         tree newargs, n;
 292         int i;
 293
 294         /* Save space: see if the result is identical to one of the args.  */
 295         if (valtype == TREE_TYPE (t1) && ! TYPE_ARG_TYPES (t2))
 296           return build_type_attribute_variant (t1, attributes);
 297         if (valtype == TREE_TYPE (t2) && ! TYPE_ARG_TYPES (t1))
 298           return build_type_attribute_variant (t2, attributes);
 299
 300         /* Simple way if one arg fails to specify argument types.  */
 301         if (TYPE_ARG_TYPES (t1) == 0)
 302          {
 303             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 304             t1 = build_type_attribute_variant (t1, attributes);
 305             return qualify_type (t1, t2);
 306          }
 307         if (TYPE_ARG_TYPES (t2) == 0)
 308          {
 309            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 310            t1 = build_type_attribute_variant (t1, attributes);
 311            return qualify_type (t1, t2);
 312          }
 313
 314         /* If both args specify argument types, we must merge the two
 315            lists, argument by argument.  */
 316         /* Tell global_bindings_p to return false so that variable_size
 317            doesn't abort on VLAs in parameter types.  */
 318         c_override_global_bindings_to_false = true;
 319
 320         len = list_length (p1);
 321         newargs = 0;
 322
 323         for (i = 0; i < len; i++)
 324           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 325
 326         n = newargs;
 327
 328         for (; p1;
 329              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 330           {
 331             /* A null type means arg type is not specified.
 332                Take whatever the other function type has.  */
 333             if (TREE_VALUE (p1) == 0)
 334               {
 335                 TREE_VALUE (n) = TREE_VALUE (p2);
 336                 goto parm_done;
 337               }
 338             if (TREE_VALUE (p2) == 0)
 339               {
 340                 TREE_VALUE (n) = TREE_VALUE (p1);
 341                 goto parm_done;
 342               }
 343
 344             /* Given  wait (union {union wait *u; int *i} *)
 345                and  wait (union wait *),
 346                prefer  union wait *  as type of parm.  */
 347             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 348                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 349               {
 350                 tree memb;
 351                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 352                      memb; memb = TREE_CHAIN (memb))
 353                   if (comptypes (TREE_TYPE (memb), TREE_VALUE (p2)))
 354                     {
 355                       TREE_VALUE (n) = TREE_VALUE (p2);
 356                       if (pedantic)
 357                         pedwarn ("function types not truly compatible in ISO C");
 358                       goto parm_done;
 359                     }
 360               }
 361             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 362                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 363               {
 364                 tree memb;
 365                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 366                      memb; memb = TREE_CHAIN (memb))
 367                   if (comptypes (TREE_TYPE (memb), TREE_VALUE (p1)))
 368                     {
 369                       TREE_VALUE (n) = TREE_VALUE (p1);
 370                       if (pedantic)
 371                         pedwarn ("function types not truly compatible in ISO C");
 372                       goto parm_done;
 373                     }
 374               }
 375             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 376           parm_done: ;
 377           }
 378
 379         c_override_global_bindings_to_false = false;
 380         t1 = build_function_type (valtype, newargs);
 381         t1 = qualify_type (t1, t2);
 382         /* ... falls through ...  */
 383       }
 384
 385     default:
 386       return build_type_attribute_variant (t1, attributes);
 387     }
 388
 389 }
 390
 391 /* Return the type of a conditional expression between pointers to
 392    possibly differently qualified versions of compatible types.
 393
 394    We assume that comp_target_types has already been done and returned
 395    nonzero; if that isn't so, this may crash.  */
 396
 397 static tree
 398 common_pointer_type (tree t1, tree t2)
 399 {
 400   tree attributes;
 401   tree pointed_to_1;
 402   tree pointed_to_2;
 403   tree target;
 404
 405   /* Save time if the two types are the same.  */
 406
 407   if (t1 == t2) return t1;
 408
 409   /* If one type is nonsense, use the other.  */
 410   if (t1 == error_mark_node)
 411     return t2;
 412   if (t2 == error_mark_node)
 413     return t1;
 414
 415   if (TREE_CODE (t1) != POINTER_TYPE || TREE_CODE (t2) != POINTER_TYPE)
 416     abort ();
 417
 418   /* Merge the attributes.  */
 419   attributes = targetm.merge_type_attributes (t1, t2);
 420
 421   /* Find the composite type of the target types, and combine the
 422      qualifiers of the two types' targets.  */
 423   pointed_to_1 = TREE_TYPE (t1);
 424   pointed_to_2 = TREE_TYPE (t2);
 425   target = composite_type (TYPE_MAIN_VARIANT (pointed_to_1),
 426                            TYPE_MAIN_VARIANT (pointed_to_2));
 427   t1 = build_pointer_type (c_build_qualified_type
 428                            (target,
 429                             TYPE_QUALS (pointed_to_1) |
 430                             TYPE_QUALS (pointed_to_2)));
 431   return build_type_attribute_variant (t1, attributes);
 432 }
 433
 434 /* Return the common type for two arithmetic types under the usual
 435    arithmetic conversions.  The default conversions have already been
 436    applied, and enumerated types converted to their compatible integer
 437    types.  The resulting type is unqualified and has no attributes.
 438
 439    This is the type for the result of most arithmetic operations
 440    if the operands have the given two types.  */
 441
 442 tree
 443 common_type (tree t1, tree t2)
 444 {
 445   enum tree_code code1;
 446   enum tree_code code2;
 447
 448   /* If one type is nonsense, use the other.  */
 449   if (t1 == error_mark_node)
 450     return t2;
 451   if (t2 == error_mark_node)
 452     return t1;
 453
 454   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 455     t1 = TYPE_MAIN_VARIANT (t1);
 456
 457   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 458     t2 = TYPE_MAIN_VARIANT (t2);
 459
 460   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 461     t1 = build_type_attribute_variant (t1, NULL_TREE);
 462
 463   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 464     t2 = build_type_attribute_variant (t2, NULL_TREE);
 465
 466   /* Save time if the two types are the same.  */
 467
 468   if (t1 == t2) return t1;
 469
 470   code1 = TREE_CODE (t1);
 471   code2 = TREE_CODE (t2);
 472
 473   if (code1 != VECTOR_TYPE && code1 != COMPLEX_TYPE
 474       && code1 != REAL_TYPE && code1 != INTEGER_TYPE)
 475     abort ();
 476
 477   if (code2 != VECTOR_TYPE && code2 != COMPLEX_TYPE
 478       && code2 != REAL_TYPE && code2 != INTEGER_TYPE)
 479     abort ();
 480
 481   /* If one type is a vector type, return that type.  (How the usual
 482      arithmetic conversions apply to the vector types extension is not
 483      precisely specified.)  */
 484   if (code1 == VECTOR_TYPE)
 485     return t1;
 486
 487   if (code2 == VECTOR_TYPE)
 488     return t2;
 489
 490   /* If one type is complex, form the common type of the non-complex
 491      components, then make that complex.  Use T1 or T2 if it is the
 492      required type.  */
 493   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 494     {
 495       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 496       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 497       tree subtype = common_type (subtype1, subtype2);
 498
 499       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 500         return t1;
 501       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 502         return t2;
 503       else
 504         return build_complex_type (subtype);
 505     }
 506
 507   /* If only one is real, use it as the result.  */
 508
 509   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 510     return t1;
 511
 512   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 513     return t2;
 514
 515   /* Both real or both integers; use the one with greater precision.  */
 516
 517   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 518     return t1;
 519   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 520     return t2;
 521
 522   /* Same precision.  Prefer long longs to longs to ints when the
 523      same precision, following the C99 rules on integer type rank
 524      (which are equivalent to the C90 rules for C90 types).  */
 525
 526   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 527       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 528     return long_long_unsigned_type_node;
 529
 530   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 531       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 532     {
 533       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 534         return long_long_unsigned_type_node;
 535       else
 536         return long_long_integer_type_node;
 537     }
 538
 539   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 540       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 541     return long_unsigned_type_node;
 542
 543   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 544       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 545     {
 546       /* But preserve unsignedness from the other type,
 547          since long cannot hold all the values of an unsigned int.  */
 548       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 549         return long_unsigned_type_node;
 550       else
 551         return long_integer_type_node;
 552     }
 553
 554   /* Likewise, prefer long double to double even if same size.  */
 555   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 556       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 557     return long_double_type_node;
 558
 559   /* Otherwise prefer the unsigned one.  */
 560
 561   if (TYPE_UNSIGNED (t1))
 562     return t1;
 563   else
 564     return t2;
 565 }
 566 \f
 567 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 568    or various other operations.  Return 2 if they are compatible
 569    but a warning may be needed if you use them together.  */
 570
 571 int
 572 comptypes (tree type1, tree type2)
 573 {
 574   tree t1 = type1;
 575   tree t2 = type2;
 576   int attrval, val;
 577
 578   /* Suppress errors caused by previously reported errors.  */
 579
 580   if (t1 == t2 || !t1 || !t2
 581       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 582     return 1;
 583
 584   /* If either type is the internal version of sizetype, return the
 585      language version.  */
 586   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 587       && TYPE_ORIG_SIZE_TYPE (t1))
 588     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 589
 590   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 591       && TYPE_ORIG_SIZE_TYPE (t2))
 592     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 593
 594
 595   /* Enumerated types are compatible with integer types, but this is
 596      not transitive: two enumerated types in the same translation unit
 597      are compatible with each other only if they are the same type.  */
 598
 599   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 600     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 601   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 602     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 603
 604   if (t1 == t2)
 605     return 1;
 606
 607   /* Different classes of types can't be compatible.  */
 608
 609   if (TREE_CODE (t1) != TREE_CODE (t2))
 610     return 0;
 611
 612   /* Qualifiers must match. C99 6.7.3p9 */
 613
 614   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 615     return 0;
 616
 617   /* Allow for two different type nodes which have essentially the same
 618      definition.  Note that we already checked for equality of the type
 619      qualifiers (just above).  */
 620
 621   if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 622     return 1;
 623
 624   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 625   if (! (attrval = targetm.comp_type_attributes (t1, t2)))
 626      return 0;
 627
 628   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 629   val = 0;
 630
 631   switch (TREE_CODE (t1))
 632     {
 633     case POINTER_TYPE:
 634       /* We must give ObjC the first crack at comparing pointers, since
 635            protocol qualifiers may be involved.  */
 636       if (c_dialect_objc () && (val = objc_comptypes (t1, t2, 0)) >= 0)
 637         break;
 638       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 639              ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
 640       break;
 641
 642     case FUNCTION_TYPE:
 643       val = function_types_compatible_p (t1, t2);
 644       break;
 645
 646     case ARRAY_TYPE:
 647       {
 648         tree d1 = TYPE_DOMAIN (t1);
 649         tree d2 = TYPE_DOMAIN (t2);
 650         bool d1_variable, d2_variable;
 651         bool d1_zero, d2_zero;
 652         val = 1;
 653
 654         /* Target types must match incl. qualifiers.  */
 655         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 656             && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
 657           return 0;
 658
 659         /* Sizes must match unless one is missing or variable.  */
 660         if (d1 == 0 || d2 == 0 || d1 == d2)
 661           break;
 662
 663         d1_zero = ! TYPE_MAX_VALUE (d1);
 664         d2_zero = ! TYPE_MAX_VALUE (d2);
 665
 666         d1_variable = (! d1_zero
 667                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 668                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 669         d2_variable = (! d2_zero
 670                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 671                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 672
 673         if (d1_variable || d2_variable)
 674           break;
 675         if (d1_zero && d2_zero)
 676           break;
 677         if (d1_zero || d2_zero
 678             || ! tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 679             || ! tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 680           val = 0;
 681
 682         break;
 683       }
 684
 685     case RECORD_TYPE:
 686       /* We are dealing with two distinct structs.  In assorted Objective-C
 687          corner cases, however, these can still be deemed equivalent.  */
 688       if (c_dialect_objc () && objc_comptypes (t1, t2, 0) == 1)
 689         val = 1;
 690
 691     case ENUMERAL_TYPE:
 692     case UNION_TYPE:
 693       if (val != 1 && !same_translation_unit_p (t1, t2))
 694         val = tagged_types_tu_compatible_p (t1, t2);
 695       break;
 696
 697     case VECTOR_TYPE:
 698       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 699             && comptypes (TREE_TYPE (t1), TREE_TYPE (t2));
 700       break;
 701
 702     default:
 703       break;
 704     }
 705   return attrval == 2 && val == 1 ? 2 : val;
 706 }
 707
 708 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 709    ignoring their qualifiers.  REFLEXIVE is only used by ObjC - set it
 710    to 1 or 0 depending if the check of the pointer types is meant to
 711    be reflexive or not (typically, assignments are not reflexive,
 712    while comparisons are reflexive).
 713 */
 714
 715 static int
 716 comp_target_types (tree ttl, tree ttr, int reflexive)
 717 {
 718   int val;
 719
 720   /* Give objc_comptypes a crack at letting these types through.  */
 721   if ((val = objc_comptypes (ttl, ttr, reflexive)) >= 0)
 722     return val;
 723
 724   val = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (ttl)),
 725                    TYPE_MAIN_VARIANT (TREE_TYPE (ttr)));
 726
 727   if (val == 2 && pedantic)
 728     pedwarn ("types are not quite compatible");
 729   return val;
 730 }
 731 \f
 732 /* Subroutines of `comptypes'.  */
 733
 734 /* Determine whether two trees derive from the same translation unit.
 735    If the CONTEXT chain ends in a null, that tree's context is still
 736    being parsed, so if two trees have context chains ending in null,
 737    they're in the same translation unit.  */
 738 int
 739 same_translation_unit_p (tree t1, tree t2)
 740 {
 741   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 742     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 743       {
 744       case 'd': t1 = DECL_CONTEXT (t1); break;
 745       case 't': t1 = TYPE_CONTEXT (t1); break;
 746       case 'x': t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 747       default: abort ();
 748       }
 749
 750   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 751     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 752       {
 753       case 'd': t2 = DECL_CONTEXT (t2); break;
 754       case 't': t2 = TYPE_CONTEXT (t2); break;
 755       case 'x': t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 756       default: abort ();
 757       }
 758
 759   return t1 == t2;
 760 }
 761
 762 /* The C standard says that two structures in different translation
 763    units are compatible with each other only if the types of their
 764    fields are compatible (among other things).  So, consider two copies
 765    of this structure:  */
 766
 767 struct tagged_tu_seen {
 768   const struct tagged_tu_seen * next;
 769   tree t1;
 770   tree t2;
 771 };
 772
 773 /* Can they be compatible with each other?  We choose to break the
 774    recursion by allowing those types to be compatible.  */
 775
 776 static const struct tagged_tu_seen * tagged_tu_seen_base;
 777
 778 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 779    compatible.  If the two types are not the same (which has been
 780    checked earlier), this can only happen when multiple translation
 781    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 782    rules.  */
 783
 784 static int
 785 tagged_types_tu_compatible_p (tree t1, tree t2)
 786 {
 787   tree s1, s2;
 788   bool needs_warning = false;
 789
 790   /* We have to verify that the tags of the types are the same.  This
 791      is harder than it looks because this may be a typedef, so we have
 792      to go look at the original type.  It may even be a typedef of a
 793      typedef...
 794      In the case of compiler-created builtin structs the TYPE_DECL
 795      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 796   while (TYPE_NAME (t1)
 797          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 798          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 799     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 800
 801   while (TYPE_NAME (t2)
 802          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 803          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 804     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 805
 806   /* C90 didn't have the requirement that the two tags be the same.  */
 807   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 808     return 0;
 809
 810   /* C90 didn't say what happened if one or both of the types were
 811      incomplete; we choose to follow C99 rules here, which is that they
 812      are compatible.  */
 813   if (TYPE_SIZE (t1) == NULL
 814       || TYPE_SIZE (t2) == NULL)
 815     return 1;
 816
 817   {
 818     const struct tagged_tu_seen * tts_i;
 819     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 820       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 821         return 1;
 822   }
 823
 824   switch (TREE_CODE (t1))
 825     {
 826     case ENUMERAL_TYPE:
 827       {
 828
 829         /* Speed up the case where the type values are in the same order.  */
 830         tree tv1 = TYPE_VALUES (t1);
 831         tree tv2 = TYPE_VALUES (t2);
 832
 833         if (tv1 == tv2)
 834           return 1;
 835
 836         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
 837           {
 838             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
 839               break;
 840             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
 841               return 0;
 842           }
 843
 844         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
 845           return 1;
 846         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
 847           return 0;
 848
 849         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
 850           return 0;
 851
 852         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
 853           {
 854             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
 855             if (s2 == NULL
 856                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
 857               return 0;
 858           }
 859         return 1;
 860       }
 861
 862     case UNION_TYPE:
 863       {
 864         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
 865           return 0;
 866
 867         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
 868           {
 869             bool ok = false;
 870             struct tagged_tu_seen tts;
 871
 872             tts.next = tagged_tu_seen_base;
 873             tts.t1 = t1;
 874             tts.t2 = t2;
 875             tagged_tu_seen_base = &tts;
 876
 877             if (DECL_NAME (s1) != NULL)
 878               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
 879                 if (DECL_NAME (s1) == DECL_NAME (s2))
 880                   {
 881                     int result;
 882                     result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 883                     if (result == 0)
 884                       break;
 885                     if (result == 2)
 886                       needs_warning = true;
 887
 888                     if (TREE_CODE (s1) == FIELD_DECL
 889                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 890                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
 891                       break;
 892
 893                     ok = true;
 894                     break;
 895                   }
 896             tagged_tu_seen_base = tts.next;
 897             if (! ok)
 898               return 0;
 899           }
 900         return needs_warning ? 2 : 1;
 901       }
 902
 903     case RECORD_TYPE:
 904       {
 905         struct tagged_tu_seen tts;
 906
 907         tts.next = tagged_tu_seen_base;
 908         tts.t1 = t1;
 909         tts.t2 = t2;
 910         tagged_tu_seen_base = &tts;
 911
 912         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
 913              s1 && s2;
 914              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
 915           {
 916             int result;
 917             if (TREE_CODE (s1) != TREE_CODE (s2)
 918                 || DECL_NAME (s1) != DECL_NAME (s2))
 919               break;
 920             result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 921             if (result == 0)
 922               break;
 923             if (result == 2)
 924               needs_warning = true;
 925
 926             if (TREE_CODE (s1) == FIELD_DECL
 927                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 928                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
 929               break;
 930           }
 931         tagged_tu_seen_base = tts.next;
 932         if (s1 && s2)
 933           return 0;
 934         return needs_warning ? 2 : 1;
 935       }
 936
 937     default:
 938       abort ();
 939     }
 940 }
 941
 942 /* Return 1 if two function types F1 and F2 are compatible.
 943    If either type specifies no argument types,
 944    the other must specify a fixed number of self-promoting arg types.
 945    Otherwise, if one type specifies only the number of arguments,
 946    the other must specify that number of self-promoting arg types.
 947    Otherwise, the argument types must match.  */
 948
 949 static int
 950 function_types_compatible_p (tree f1, tree f2)
 951 {
 952   tree args1, args2;
 953   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 954   int val = 1;
 955   int val1;
 956   tree ret1, ret2;
 957
 958   ret1 = TREE_TYPE (f1);
 959   ret2 = TREE_TYPE (f2);
 960
 961   /* 'volatile' qualifiers on a function's return type used to mean
 962      the function is noreturn.  */
 963   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
 964     pedwarn ("function return types not compatible due to `volatile'");
 965   if (TYPE_VOLATILE (ret1))
 966     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
 967                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
 968   if (TYPE_VOLATILE (ret2))
 969     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
 970                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
 971   val = comptypes (ret1, ret2);
 972   if (val == 0)
 973     return 0;
 974
 975   args1 = TYPE_ARG_TYPES (f1);
 976   args2 = TYPE_ARG_TYPES (f2);
 977
 978   /* An unspecified parmlist matches any specified parmlist
 979      whose argument types don't need default promotions.  */
 980
 981   if (args1 == 0)
 982     {
 983       if (!self_promoting_args_p (args2))
 984         return 0;
 985       /* If one of these types comes from a non-prototype fn definition,
 986          compare that with the other type's arglist.
 987          If they don't match, ask for a warning (but no error).  */
 988       if (TYPE_ACTUAL_ARG_TYPES (f1)
 989           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
 990         val = 2;
 991       return val;
 992     }
 993   if (args2 == 0)
 994     {
 995       if (!self_promoting_args_p (args1))
 996         return 0;
 997       if (TYPE_ACTUAL_ARG_TYPES (f2)
 998           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
 999         val = 2;
1000       return val;
1001     }
1002
1003   /* Both types have argument lists: compare them and propagate results.  */
1004   val1 = type_lists_compatible_p (args1, args2);
1005   return val1 != 1 ? val1 : val;
1006 }
1007
1008 /* Check two lists of types for compatibility,
1009    returning 0 for incompatible, 1 for compatible,
1010    or 2 for compatible with warning.  */
1011
1012 static int
1013 type_lists_compatible_p (tree args1, tree args2)
1014 {
1015   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1016   int val = 1;
1017   int newval = 0;
1018
1019   while (1)
1020     {
1021       if (args1 == 0 && args2 == 0)
1022         return val;
1023       /* If one list is shorter than the other,
1024          they fail to match.  */
1025       if (args1 == 0 || args2 == 0)
1026         return 0;
1027       /* A null pointer instead of a type
1028          means there is supposed to be an argument
1029          but nothing is specified about what type it has.
1030          So match anything that self-promotes.  */
1031       if (TREE_VALUE (args1) == 0)
1032         {
1033           if (c_type_promotes_to (TREE_VALUE (args2)) != TREE_VALUE (args2))
1034             return 0;
1035         }
1036       else if (TREE_VALUE (args2) == 0)
1037         {
1038           if (c_type_promotes_to (TREE_VALUE (args1)) != TREE_VALUE (args1))
1039             return 0;
1040         }
1041       /* If one of the lists has an error marker, ignore this arg.  */
1042       else if (TREE_CODE (TREE_VALUE (args1)) == ERROR_MARK
1043                || TREE_CODE (TREE_VALUE (args2)) == ERROR_MARK)
1044         ;
1045       else if (! (newval = comptypes (TYPE_MAIN_VARIANT (TREE_VALUE (args1)),
1046                                       TYPE_MAIN_VARIANT (TREE_VALUE (args2)))))
1047         {
1048           /* Allow  wait (union {union wait *u; int *i} *)
1049              and  wait (union wait *)  to be compatible.  */
1050           if (TREE_CODE (TREE_VALUE (args1)) == UNION_TYPE
1051               && (TYPE_NAME (TREE_VALUE (args1)) == 0
1052                   || TYPE_TRANSPARENT_UNION (TREE_VALUE (args1)))
1053               && TREE_CODE (TYPE_SIZE (TREE_VALUE (args1))) == INTEGER_CST
1054               && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args1)),
1055                                      TYPE_SIZE (TREE_VALUE (args2))))
1056             {
1057               tree memb;
1058               for (memb = TYPE_FIELDS (TREE_VALUE (args1));
1059                    memb; memb = TREE_CHAIN (memb))
1060                 if (comptypes (TREE_TYPE (memb), TREE_VALUE (args2)))
1061                   break;
1062               if (memb == 0)
1063                 return 0;
1064             }
1065           else if (TREE_CODE (TREE_VALUE (args2)) == UNION_TYPE
1066                    && (TYPE_NAME (TREE_VALUE (args2)) == 0
1067                        || TYPE_TRANSPARENT_UNION (TREE_VALUE (args2)))
1068                    && TREE_CODE (TYPE_SIZE (TREE_VALUE (args2))) == INTEGER_CST
1069                    && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args2)),
1070                                           TYPE_SIZE (TREE_VALUE (args1))))
1071             {
1072               tree memb;
1073               for (memb = TYPE_FIELDS (TREE_VALUE (args2));
1074                    memb; memb = TREE_CHAIN (memb))
1075                 if (comptypes (TREE_TYPE (memb), TREE_VALUE (args1)))
1076                   break;
1077               if (memb == 0)
1078                 return 0;
1079             }
1080           else
1081             return 0;
1082         }
1083
1084       /* comptypes said ok, but record if it said to warn.  */
1085       if (newval > val)
1086         val = newval;
1087
1088       args1 = TREE_CHAIN (args1);
1089       args2 = TREE_CHAIN (args2);
1090     }
1091 }
1092 \f
1093 /* Compute the size to increment a pointer by.  */
1094
1095 tree
1096 c_size_in_bytes (tree type)
1097 {
1098   enum tree_code code = TREE_CODE (type);
1099
1100   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1101     return size_one_node;
1102
1103   if (!COMPLETE_OR_VOID_TYPE_P (type))
1104     {
1105       error ("arithmetic on pointer to an incomplete type");
1106       return size_one_node;
1107     }
1108
1109   /* Convert in case a char is more than one unit.  */
1110   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1111                      size_int (TYPE_PRECISION (char_type_node)
1112                                / BITS_PER_UNIT));
1113 }
1114 \f
1115 /* Return either DECL or its known constant value (if it has one).  */
1116
1117 tree
1118 decl_constant_value (tree decl)
1119 {
1120   if (/* Don't change a variable array bound or initial value to a constant
1121          in a place where a variable is invalid.  Note that DECL_INITIAL
1122          isn't valid for a PARM_DECL.  */
1123       current_function_decl != 0
1124       && TREE_CODE (decl) != PARM_DECL
1125       && ! TREE_THIS_VOLATILE (decl)
1126       && TREE_READONLY (decl)
1127       && DECL_INITIAL (decl) != 0
1128       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1129       /* This is invalid if initial value is not constant.
1130          If it has either a function call, a memory reference,
1131          or a variable, then re-evaluating it could give different results.  */
1132       && TREE_CONSTANT (DECL_INITIAL (decl))
1133       /* Check for cases where this is sub-optimal, even though valid.  */
1134       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1135     return DECL_INITIAL (decl);
1136   return decl;
1137 }
1138
1139 /* Return either DECL or its known constant value (if it has one), but
1140    return DECL if pedantic or DECL has mode BLKmode.  This is for
1141    bug-compatibility with the old behavior of decl_constant_value
1142    (before GCC 3.0); every use of this function is a bug and it should
1143    be removed before GCC 3.1.  It is not appropriate to use pedantic
1144    in a way that affects optimization, and BLKmode is probably not the
1145    right test for avoiding misoptimizations either.  */
1146
1147 static tree
1148 decl_constant_value_for_broken_optimization (tree decl)
1149 {
1150   if (pedantic || DECL_MODE (decl) == BLKmode)
1151     return decl;
1152   else
1153     return decl_constant_value (decl);
1154 }
1155
1156
1157 /* Perform the default conversion of arrays and functions to pointers.
1158    Return the result of converting EXP.  For any other expression, just
1159    return EXP.  */
1160
1161 static tree
1162 default_function_array_conversion (tree exp)
1163 {
1164   tree orig_exp;
1165   tree type = TREE_TYPE (exp);
1166   enum tree_code code = TREE_CODE (type);
1167   int not_lvalue = 0;
1168
1169   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1170      an lvalue.
1171
1172      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1173      to integer and cause infinite recursion.  */
1174   orig_exp = exp;
1175   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1176          || (TREE_CODE (exp) == NOP_EXPR
1177              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1178     {
1179       if (TREE_CODE (exp) == NON_LVALUE_EXPR)
1180         not_lvalue = 1;
1181       exp = TREE_OPERAND (exp, 0);
1182     }
1183
1184   if (TREE_NO_WARNING (orig_exp))
1185     TREE_NO_WARNING (exp) = 1;
1186
1187   if (code == FUNCTION_TYPE)
1188     {
1189       return build_unary_op (ADDR_EXPR, exp, 0);
1190     }
1191   if (code == ARRAY_TYPE)
1192     {
1193       tree adr;
1194       tree restype = TREE_TYPE (type);
1195       tree ptrtype;
1196       int constp = 0;
1197       int volatilep = 0;
1198       int lvalue_array_p;
1199
1200       if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'r' || DECL_P (exp))
1201         {
1202           constp = TREE_READONLY (exp);
1203           volatilep = TREE_THIS_VOLATILE (exp);
1204         }
1205
1206       if (TYPE_QUALS (type) || constp || volatilep)
1207         restype
1208           = c_build_qualified_type (restype,
1209                                     TYPE_QUALS (type)
1210                                     | (constp * TYPE_QUAL_CONST)
1211                                     | (volatilep * TYPE_QUAL_VOLATILE));
1212
1213       if (TREE_CODE (exp) == INDIRECT_REF)
1214         return convert (build_pointer_type (restype),
1215                         TREE_OPERAND (exp, 0));
1216
1217       if (TREE_CODE (exp) == COMPOUND_EXPR)
1218         {
1219           tree op1 = default_conversion (TREE_OPERAND (exp, 1));
1220           return build (COMPOUND_EXPR, TREE_TYPE (op1),
1221                         TREE_OPERAND (exp, 0), op1);
1222         }
1223
1224       lvalue_array_p = !not_lvalue && lvalue_p (exp);
1225       if (!flag_isoc99 && !lvalue_array_p)
1226         {
1227           /* Before C99, non-lvalue arrays do not decay to pointers.
1228              Normally, using such an array would be invalid; but it can
1229              be used correctly inside sizeof or as a statement expression.
1230              Thus, do not give an error here; an error will result later.  */
1231           return exp;
1232         }
1233
1234       ptrtype = build_pointer_type (restype);
1235
1236       if (TREE_CODE (exp) == VAR_DECL)
1237         {
1238           /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1239              ADDR_EXPR because it's the best way of representing what
1240              happens in C when we take the address of an array and place
1241              it in a pointer to the element type.  */
1242           adr = build1 (ADDR_EXPR, ptrtype, exp);
1243           if (!c_mark_addressable (exp))
1244             return error_mark_node;
1245           TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1246           return adr;
1247         }
1248       /* This way is better for a COMPONENT_REF since it can
1249          simplify the offset for a component.  */
1250       adr = build_unary_op (ADDR_EXPR, exp, 1);
1251       return convert (ptrtype, adr);
1252     }
1253   return exp;
1254 }
1255
1256 /* Perform default promotions for C data used in expressions.
1257    Arrays and functions are converted to pointers;
1258    enumeral types or short or char, to int.
1259    In addition, manifest constants symbols are replaced by their values.  */
1260
1261 tree
1262 default_conversion (tree exp)
1263 {
1264   tree orig_exp;
1265   tree type = TREE_TYPE (exp);
1266   enum tree_code code = TREE_CODE (type);
1267
1268   if (code == FUNCTION_TYPE || code == ARRAY_TYPE)
1269     return default_function_array_conversion (exp);
1270
1271   /* Constants can be used directly unless they're not loadable.  */
1272   if (TREE_CODE (exp) == CONST_DECL)
1273     exp = DECL_INITIAL (exp);
1274
1275   /* Replace a nonvolatile const static variable with its value unless
1276      it is an array, in which case we must be sure that taking the
1277      address of the array produces consistent results.  */
1278   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1279     {
1280       exp = decl_constant_value_for_broken_optimization (exp);
1281       type = TREE_TYPE (exp);
1282     }
1283
1284   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1285      an lvalue.
1286
1287      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1288      to integer and cause infinite recursion.  */
1289   orig_exp = exp;
1290   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1291          || (TREE_CODE (exp) == NOP_EXPR
1292              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1293     exp = TREE_OPERAND (exp, 0);
1294
1295   if (TREE_NO_WARNING (orig_exp))
1296     TREE_NO_WARNING (exp) = 1;
1297
1298   /* Normally convert enums to int,
1299      but convert wide enums to something wider.  */
1300   if (code == ENUMERAL_TYPE)
1301     {
1302       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1303                                           TYPE_PRECISION (integer_type_node)),
1304                                      ((TYPE_PRECISION (type)
1305                                        >= TYPE_PRECISION (integer_type_node))
1306                                       && TYPE_UNSIGNED (type)));
1307
1308       return convert (type, exp);
1309     }
1310
1311   if (TREE_CODE (exp) == COMPONENT_REF
1312       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1313       /* If it's thinner than an int, promote it like a
1314          c_promoting_integer_type_p, otherwise leave it alone.  */
1315       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1316                                TYPE_PRECISION (integer_type_node)))
1317     return convert (integer_type_node, exp);
1318
1319   if (c_promoting_integer_type_p (type))
1320     {
1321       /* Preserve unsignedness if not really getting any wider.  */
1322       if (TYPE_UNSIGNED (type)
1323           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1324         return convert (unsigned_type_node, exp);
1325
1326       return convert (integer_type_node, exp);
1327     }
1328
1329   if (code == VOID_TYPE)
1330     {
1331       error ("void value not ignored as it ought to be");
1332       return error_mark_node;
1333     }
1334   return exp;
1335 }
1336 \f
1337 /* Look up COMPONENT in a structure or union DECL.
1338
1339    If the component name is not found, returns NULL_TREE.  Otherwise,
1340    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1341    stepping down the chain to the component, which is in the last
1342    TREE_VALUE of the list.  Normally the list is of length one, but if
1343    the component is embedded within (nested) anonymous structures or
1344    unions, the list steps down the chain to the component.  */
1345
1346 static tree
1347 lookup_field (tree decl, tree component)
1348 {
1349   tree type = TREE_TYPE (decl);
1350   tree field;
1351
1352   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1353      to the field elements.  Use a binary search on this array to quickly
1354      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1355      will always be set for structures which have many elements.  */
1356
1357   if (TYPE_LANG_SPECIFIC (type))
1358     {
1359       int bot, top, half;
1360       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1361
1362       field = TYPE_FIELDS (type);
1363       bot = 0;
1364       top = TYPE_LANG_SPECIFIC (type)->s->len;
1365       while (top - bot > 1)
1366         {
1367           half = (top - bot + 1) >> 1;
1368           field = field_array[bot+half];
1369
1370           if (DECL_NAME (field) == NULL_TREE)
1371             {
1372               /* Step through all anon unions in linear fashion.  */
1373               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1374                 {
1375                   field = field_array[bot++];
1376                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1377                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1378                     {
1379                       tree anon = lookup_field (field, component);
1380
1381                       if (anon)
1382                         return tree_cons (NULL_TREE, field, anon);
1383                     }
1384                 }
1385
1386               /* Entire record is only anon unions.  */
1387               if (bot > top)
1388                 return NULL_TREE;
1389
1390               /* Restart the binary search, with new lower bound.  */
1391               continue;
1392             }
1393
1394           if (DECL_NAME (field) == component)
1395             break;
1396           if (DECL_NAME (field) < component)
1397             bot += half;
1398           else
1399             top = bot + half;
1400         }
1401
1402       if (DECL_NAME (field_array[bot]) == component)
1403         field = field_array[bot];
1404       else if (DECL_NAME (field) != component)
1405         return NULL_TREE;
1406     }
1407   else
1408     {
1409       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1410         {
1411           if (DECL_NAME (field) == NULL_TREE
1412               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1413                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1414             {
1415               tree anon = lookup_field (field, component);
1416
1417               if (anon)
1418                 return tree_cons (NULL_TREE, field, anon);
1419             }
1420
1421           if (DECL_NAME (field) == component)
1422             break;
1423         }
1424
1425       if (field == NULL_TREE)
1426         return NULL_TREE;
1427     }
1428
1429   return tree_cons (NULL_TREE, field, NULL_TREE);
1430 }
1431
1432 /* Make an expression to refer to the COMPONENT field of
1433    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1434
1435 tree
1436 build_component_ref (tree datum, tree component)
1437 {
1438   tree type = TREE_TYPE (datum);
1439   enum tree_code code = TREE_CODE (type);
1440   tree field = NULL;
1441   tree ref;
1442
1443   if (!objc_is_public (datum, component))
1444     return error_mark_node;
1445
1446   /* If DATUM is a COMPOUND_EXPR, move our reference inside it.
1447      Ensure that the arguments are not lvalues; otherwise,
1448      if the component is an array, it would wrongly decay to a pointer in
1449      C89 mode.
1450      We cannot do this with a COND_EXPR, because in a conditional expression
1451      the default promotions are applied to both sides, and this would yield
1452      the wrong type of the result; for example, if the components have
1453      type "char".  */
1454   switch (TREE_CODE (datum))
1455     {
1456     case COMPOUND_EXPR:
1457       {
1458         tree value = build_component_ref (TREE_OPERAND (datum, 1), component);
1459         return build (COMPOUND_EXPR, TREE_TYPE (value),
1460                       TREE_OPERAND (datum, 0), non_lvalue (value));
1461       }
1462     default:
1463       break;
1464     }
1465
1466   /* See if there is a field or component with name COMPONENT.  */
1467
1468   if (code == RECORD_TYPE || code == UNION_TYPE)
1469     {
1470       if (!COMPLETE_TYPE_P (type))
1471         {
1472           c_incomplete_type_error (NULL_TREE, type);
1473           return error_mark_node;
1474         }
1475
1476       field = lookup_field (datum, component);
1477
1478       if (!field)
1479         {
1480           error ("%s has no member named `%s'",
1481                  code == RECORD_TYPE ? "structure" : "union",
1482                  IDENTIFIER_POINTER (component));
1483           return error_mark_node;
1484         }
1485
1486       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1487          This might be better solved in future the way the C++ front
1488          end does it - by giving the anonymous entities each a
1489          separate name and type, and then have build_component_ref
1490          recursively call itself.  We can't do that here.  */
1491       do
1492         {
1493           tree subdatum = TREE_VALUE (field);
1494
1495           if (TREE_TYPE (subdatum) == error_mark_node)
1496             return error_mark_node;
1497
1498           ref = build (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1499                        NULL_TREE);
1500           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1501             TREE_READONLY (ref) = 1;
1502           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1503             TREE_THIS_VOLATILE (ref) = 1;
1504
1505           if (TREE_DEPRECATED (subdatum))
1506             warn_deprecated_use (subdatum);
1507
1508           datum = ref;
1509
1510           field = TREE_CHAIN (field);
1511         }
1512       while (field);
1513
1514       return ref;
1515     }
1516   else if (code != ERROR_MARK)
1517     error ("request for member `%s' in something not a structure or union",
1518             IDENTIFIER_POINTER (component));
1519
1520   return error_mark_node;
1521 }
1522 \f
1523 /* Given an expression PTR for a pointer, return an expression
1524    for the value pointed to.
1525    ERRORSTRING is the name of the operator to appear in error messages.  */
1526
1527 tree
1528 build_indirect_ref (tree ptr, const char *errorstring)
1529 {
1530   tree pointer = default_conversion (ptr);
1531   tree type = TREE_TYPE (pointer);
1532
1533   if (TREE_CODE (type) == POINTER_TYPE)
1534     {
1535       if (TREE_CODE (pointer) == ADDR_EXPR
1536           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1537               == TREE_TYPE (type)))
1538         return TREE_OPERAND (pointer, 0);
1539       else
1540         {
1541           tree t = TREE_TYPE (type);
1542           tree ref = build1 (INDIRECT_REF, TYPE_MAIN_VARIANT (t), pointer);
1543
1544           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1545             {
1546               error ("dereferencing pointer to incomplete type");
1547               return error_mark_node;
1548             }
1549           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1550             warning ("dereferencing `void *' pointer");
1551
1552           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1553              so that we get the proper error message if the result is used
1554              to assign to.  Also, &* is supposed to be a no-op.
1555              And ANSI C seems to specify that the type of the result
1556              should be the const type.  */
1557           /* A de-reference of a pointer to const is not a const.  It is valid
1558              to change it via some other pointer.  */
1559           TREE_READONLY (ref) = TYPE_READONLY (t);
1560           TREE_SIDE_EFFECTS (ref)
1561             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1562           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1563           return ref;
1564         }
1565     }
1566   else if (TREE_CODE (pointer) != ERROR_MARK)
1567     error ("invalid type argument of `%s'", errorstring);
1568   return error_mark_node;
1569 }
1570
1571 /* This handles expressions of the form "a[i]", which denotes
1572    an array reference.
1573
1574    This is logically equivalent in C to *(a+i), but we may do it differently.
1575    If A is a variable or a member, we generate a primitive ARRAY_REF.
1576    This avoids forcing the array out of registers, and can work on
1577    arrays that are not lvalues (for example, members of structures returned
1578    by functions).  */
1579
1580 tree
1581 build_array_ref (tree array, tree index)
1582 {
1583   if (index == 0)
1584     {
1585       error ("subscript missing in array reference");
1586       return error_mark_node;
1587     }
1588
1589   if (TREE_TYPE (array) == error_mark_node
1590       || TREE_TYPE (index) == error_mark_node)
1591     return error_mark_node;
1592
1593   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1594     {
1595       tree rval, type;
1596
1597       /* Subscripting with type char is likely to lose
1598          on a machine where chars are signed.
1599          So warn on any machine, but optionally.
1600          Don't warn for unsigned char since that type is safe.
1601          Don't warn for signed char because anyone who uses that
1602          must have done so deliberately.  */
1603       if (warn_char_subscripts
1604           && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1605         warning ("array subscript has type `char'");
1606
1607       /* Apply default promotions *after* noticing character types.  */
1608       index = default_conversion (index);
1609
1610       /* Require integer *after* promotion, for sake of enums.  */
1611       if (TREE_CODE (TREE_TYPE (index)) != INTEGER_TYPE)
1612         {
1613           error ("array subscript is not an integer");
1614           return error_mark_node;
1615         }
1616
1617       /* An array that is indexed by a non-constant
1618          cannot be stored in a register; we must be able to do
1619          address arithmetic on its address.
1620          Likewise an array of elements of variable size.  */
1621       if (TREE_CODE (index) != INTEGER_CST
1622           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1623               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1624         {
1625           if (!c_mark_addressable (array))
1626             return error_mark_node;
1627         }
1628       /* An array that is indexed by a constant value which is not within
1629          the array bounds cannot be stored in a register either; because we
1630          would get a crash in store_bit_field/extract_bit_field when trying
1631          to access a non-existent part of the register.  */
1632       if (TREE_CODE (index) == INTEGER_CST
1633           && TYPE_DOMAIN (TREE_TYPE (array))
1634           && ! int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1635         {
1636           if (!c_mark_addressable (array))
1637             return error_mark_node;
1638         }
1639
1640       if (pedantic)
1641         {
1642           tree foo = array;
1643           while (TREE_CODE (foo) == COMPONENT_REF)
1644             foo = TREE_OPERAND (foo, 0);
1645           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1646             pedwarn ("ISO C forbids subscripting `register' array");
1647           else if (! flag_isoc99 && ! lvalue_p (foo))
1648             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1649         }
1650
1651       type = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (array)));
1652       rval = build (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1653       /* Array ref is const/volatile if the array elements are
1654          or if the array is.  */
1655       TREE_READONLY (rval)
1656         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1657             | TREE_READONLY (array));
1658       TREE_SIDE_EFFECTS (rval)
1659         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1660             | TREE_SIDE_EFFECTS (array));
1661       TREE_THIS_VOLATILE (rval)
1662         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1663             /* This was added by rms on 16 Nov 91.
1664                It fixes  vol struct foo *a;  a->elts[1]
1665                in an inline function.
1666                Hope it doesn't break something else.  */
1667             | TREE_THIS_VOLATILE (array));
1668       return require_complete_type (fold (rval));
1669     }
1670
1671   {
1672     tree ar = default_conversion (array);
1673     tree ind = default_conversion (index);
1674
1675     /* Do the same warning check as above, but only on the part that's
1676        syntactically the index and only if it is also semantically
1677        the index.  */
1678     if (warn_char_subscripts
1679         && TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE
1680         && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1681       warning ("subscript has type `char'");
1682
1683     /* Put the integer in IND to simplify error checking.  */
1684     if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
1685       {
1686         tree temp = ar;
1687         ar = ind;
1688         ind = temp;
1689       }
1690
1691     if (ar == error_mark_node)
1692       return ar;
1693
1694     if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE
1695         || TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) == FUNCTION_TYPE)
1696       {
1697         error ("subscripted value is neither array nor pointer");
1698         return error_mark_node;
1699       }
1700     if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
1701       {
1702         error ("array subscript is not an integer");
1703         return error_mark_node;
1704       }
1705
1706     return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, ind, 0),
1707                                "array indexing");
1708   }
1709 }
1710 \f
1711 /* Build an external reference to identifier ID.  FUN indicates
1712    whether this will be used for a function call.  */
1713 tree
1714 build_external_ref (tree id, int fun)
1715 {
1716   tree ref;
1717   tree decl = lookup_name (id);
1718   tree objc_ivar = lookup_objc_ivar (id);
1719
1720   if (decl && decl != error_mark_node)
1721     {
1722       /* Properly declared variable or function reference.  */
1723       if (!objc_ivar)
1724         ref = decl;
1725       else if (decl != objc_ivar && !DECL_FILE_SCOPE_P (decl))
1726         {
1727           warning ("local declaration of `%s' hides instance variable",
1728                    IDENTIFIER_POINTER (id));
1729           ref = decl;
1730         }
1731       else
1732         ref = objc_ivar;
1733     }
1734   else if (objc_ivar)
1735     ref = objc_ivar;
1736   else if (fun)
1737     /* Implicit function declaration.  */
1738     ref = implicitly_declare (id);
1739   else if (decl == error_mark_node)
1740     /* Don't complain about something that's already been
1741        complained about.  */
1742     return error_mark_node;
1743   else
1744     {
1745       undeclared_variable (id);
1746       return error_mark_node;
1747     }
1748
1749   if (TREE_TYPE (ref) == error_mark_node)
1750     return error_mark_node;
1751
1752   if (TREE_DEPRECATED (ref))
1753     warn_deprecated_use (ref);
1754
1755   if (!skip_evaluation)
1756     assemble_external (ref);
1757   TREE_USED (ref) = 1;
1758
1759   if (TREE_CODE (ref) == CONST_DECL)
1760     {
1761       ref = DECL_INITIAL (ref);
1762       TREE_CONSTANT (ref) = 1;
1763       TREE_INVARIANT (ref) = 1;
1764     }
1765   else if (current_function_decl != 0
1766            && !DECL_FILE_SCOPE_P (current_function_decl)
1767            && (TREE_CODE (ref) == VAR_DECL
1768                || TREE_CODE (ref) == PARM_DECL
1769                || TREE_CODE (ref) == FUNCTION_DECL))
1770     {
1771       tree context = decl_function_context (ref);
1772
1773       if (context != 0 && context != current_function_decl)
1774         DECL_NONLOCAL (ref) = 1;
1775     }
1776
1777   return ref;
1778 }
1779
1780 /* Build a function call to function FUNCTION with parameters PARAMS.
1781    PARAMS is a list--a chain of TREE_LIST nodes--in which the
1782    TREE_VALUE of each node is a parameter-expression.
1783    FUNCTION's data type may be a function type or a pointer-to-function.  */
1784
1785 tree
1786 build_function_call (tree function, tree params)
1787 {
1788   tree fntype, fundecl = 0;
1789   tree coerced_params;
1790   tree name = NULL_TREE, result;
1791   tree tem;
1792
1793   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
1794   STRIP_TYPE_NOPS (function);
1795
1796   /* Convert anything with function type to a pointer-to-function.  */
1797   if (TREE_CODE (function) == FUNCTION_DECL)
1798     {
1799       name = DECL_NAME (function);
1800
1801       /* Differs from default_conversion by not setting TREE_ADDRESSABLE
1802          (because calling an inline function does not mean the function
1803          needs to be separately compiled).  */
1804       fntype = build_type_variant (TREE_TYPE (function),
1805                                    TREE_READONLY (function),
1806                                    TREE_THIS_VOLATILE (function));
1807       fundecl = function;
1808       function = build1 (ADDR_EXPR, build_pointer_type (fntype), function);
1809     }
1810   else
1811     function = default_conversion (function);
1812
1813   fntype = TREE_TYPE (function);
1814
1815   if (TREE_CODE (fntype) == ERROR_MARK)
1816     return error_mark_node;
1817
1818   if (!(TREE_CODE (fntype) == POINTER_TYPE
1819         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
1820     {
1821       error ("called object is not a function");
1822       return error_mark_node;
1823     }
1824
1825   if (fundecl && TREE_THIS_VOLATILE (fundecl))
1826     current_function_returns_abnormally = 1;
1827
1828   /* fntype now gets the type of function pointed to.  */
1829   fntype = TREE_TYPE (fntype);
1830
1831   /* Check that the function is called through a compatible prototype.
1832      If it is not, replace the call by a trap, wrapped up in a compound
1833      expression if necessary.  This has the nice side-effect to prevent
1834      the tree-inliner from generating invalid assignment trees which may
1835      blow up in the RTL expander later.
1836
1837      ??? This doesn't work for Objective-C because objc_comptypes
1838      refuses to compare function prototypes, yet the compiler appears
1839      to build calls that are flagged as invalid by C's comptypes.  */
1840   if (! c_dialect_objc ()
1841       && TREE_CODE (function) == NOP_EXPR
1842       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
1843       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
1844       && ! comptypes (fntype, TREE_TYPE (tem)))
1845     {
1846       tree return_type = TREE_TYPE (fntype);
1847       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
1848                                        NULL_TREE);
1849
1850       /* This situation leads to run-time undefined behavior.  We can't,
1851          therefore, simply error unless we can prove that all possible
1852          executions of the program must execute the code.  */
1853       warning ("function called through a non-compatible type");
1854
1855       /* We can, however, treat "undefined" any way we please.
1856          Call abort to encourage the user to fix the program.  */
1857       inform ("if this code is reached, the program will abort");
1858
1859       if (VOID_TYPE_P (return_type))
1860         return trap;
1861       else
1862         {
1863           tree rhs;
1864
1865           if (AGGREGATE_TYPE_P (return_type))
1866             rhs = build_compound_literal (return_type,
1867                                           build_constructor (return_type,
1868                                                              NULL_TREE));
1869           else
1870             rhs = fold (build1 (NOP_EXPR, return_type, integer_zero_node));
1871
1872           return build (COMPOUND_EXPR, return_type, trap, rhs);
1873         }
1874     }
1875
1876   /* Convert the parameters to the types declared in the
1877      function prototype, or apply default promotions.  */
1878
1879   coerced_params
1880     = convert_arguments (TYPE_ARG_TYPES (fntype), params, name, fundecl);
1881
1882   /* Check that the arguments to the function are valid.  */
1883
1884   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params);
1885
1886   result = build (CALL_EXPR, TREE_TYPE (fntype),
1887                   function, coerced_params, NULL_TREE);
1888   TREE_SIDE_EFFECTS (result) = 1;
1889
1890   if (require_constant_value)
1891     {
1892       result = fold_initializer (result);
1893
1894       if (TREE_CONSTANT (result)
1895           && (name == NULL_TREE
1896               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
1897         pedwarn_init ("initializer element is not constant");
1898     }
1899   else
1900     result = fold (result);
1901
1902   if (VOID_TYPE_P (TREE_TYPE (result)))
1903     return result;
1904   return require_complete_type (result);
1905 }
1906 \f
1907 /* Convert the argument expressions in the list VALUES
1908    to the types in the list TYPELIST.  The result is a list of converted
1909    argument expressions.
1910
1911    If TYPELIST is exhausted, or when an element has NULL as its type,
1912    perform the default conversions.
1913
1914    PARMLIST is the chain of parm decls for the function being called.
1915    It may be 0, if that info is not available.
1916    It is used only for generating error messages.
1917
1918    NAME is an IDENTIFIER_NODE or 0.  It is used only for error messages.
1919
1920    This is also where warnings about wrong number of args are generated.
1921
1922    Both VALUES and the returned value are chains of TREE_LIST nodes
1923    with the elements of the list in the TREE_VALUE slots of those nodes.  */
1924
1925 static tree
1926 convert_arguments (tree typelist, tree values, tree name, tree fundecl)
1927 {
1928   tree typetail, valtail;
1929   tree result = NULL;
1930   int parmnum;
1931
1932   /* Scan the given expressions and types, producing individual
1933      converted arguments and pushing them on RESULT in reverse order.  */
1934
1935   for (valtail = values, typetail = typelist, parmnum = 0;
1936        valtail;
1937        valtail = TREE_CHAIN (valtail), parmnum++)
1938     {
1939       tree type = typetail ? TREE_VALUE (typetail) : 0;
1940       tree val = TREE_VALUE (valtail);
1941
1942       if (type == void_type_node)
1943         {
1944           if (name)
1945             error ("too many arguments to function `%s'",
1946                    IDENTIFIER_POINTER (name));
1947           else
1948             error ("too many arguments to function");
1949           break;
1950         }
1951
1952       /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
1953       /* Do not use STRIP_NOPS here!  We do not want an enumerator with value 0
1954          to convert automatically to a pointer.  */
1955       if (TREE_CODE (val) == NON_LVALUE_EXPR)
1956         val = TREE_OPERAND (val, 0);
1957
1958       val = default_function_array_conversion (val);
1959
1960       val = require_complete_type (val);
1961
1962       if (type != 0)
1963         {
1964           /* Formal parm type is specified by a function prototype.  */
1965           tree parmval;
1966
1967           if (!COMPLETE_TYPE_P (type))
1968             {
1969               error ("type of formal parameter %d is incomplete", parmnum + 1);
1970               parmval = val;
1971             }
1972           else
1973             {
1974               /* Optionally warn about conversions that
1975                  differ from the default conversions.  */
1976               if (warn_conversion || warn_traditional)
1977                 {
1978                   int formal_prec = TYPE_PRECISION (type);
1979
1980                   if (INTEGRAL_TYPE_P (type)
1981                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
1982                     warn_for_assignment ("%s as integer rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1983                   if (INTEGRAL_TYPE_P (type)
1984                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
1985                     warn_for_assignment ("%s as integer rather than complex due to prototype", (char *) 0, name, parmnum + 1);
1986                   else if (TREE_CODE (type) == COMPLEX_TYPE
1987                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
1988                     warn_for_assignment ("%s as complex rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1989                   else if (TREE_CODE (type) == REAL_TYPE
1990                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
1991                     warn_for_assignment ("%s as floating rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1992                   else if (TREE_CODE (type) == COMPLEX_TYPE
1993                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
1994                     warn_for_assignment ("%s as complex rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1995                   else if (TREE_CODE (type) == REAL_TYPE
1996                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
1997                     warn_for_assignment ("%s as floating rather than complex due to prototype", (char *) 0, name, parmnum + 1);
1998                   /* ??? At some point, messages should be written about
1999                      conversions between complex types, but that's too messy
2000                      to do now.  */
2001                   else if (TREE_CODE (type) == REAL_TYPE
2002                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2003                     {
2004                       /* Warn if any argument is passed as `float',
2005                          since without a prototype it would be `double'.  */
2006                       if (formal_prec == TYPE_PRECISION (float_type_node))
2007                         warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
2008                     }
2009                   /* Detect integer changing in width or signedness.
2010                      These warnings are only activated with
2011                      -Wconversion, not with -Wtraditional.  */
2012                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2013                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2014                     {
2015                       tree would_have_been = default_conversion (val);
2016                       tree type1 = TREE_TYPE (would_have_been);
2017
2018                       if (TREE_CODE (type) == ENUMERAL_TYPE
2019                           && (TYPE_MAIN_VARIANT (type)
2020                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2021                         /* No warning if function asks for enum
2022                            and the actual arg is that enum type.  */
2023                         ;
2024                       else if (formal_prec != TYPE_PRECISION (type1))
2025                         warn_for_assignment ("%s with different width due to prototype", (char *) 0, name, parmnum + 1);
2026                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2027                         ;
2028                       /* Don't complain if the formal parameter type
2029                          is an enum, because we can't tell now whether
2030                          the value was an enum--even the same enum.  */
2031                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2032                         ;
2033                       else if (TREE_CODE (val) == INTEGER_CST
2034                                && int_fits_type_p (val, type))
2035                         /* Change in signedness doesn't matter
2036                            if a constant value is unaffected.  */
2037                         ;
2038                       /* Likewise for a constant in a NOP_EXPR.  */
2039                       else if (TREE_CODE (val) == NOP_EXPR
2040                                && TREE_CODE (TREE_OPERAND (val, 0)) == INTEGER_CST
2041                                && int_fits_type_p (TREE_OPERAND (val, 0), type))
2042                         ;
2043                       /* If the value is extended from a narrower
2044                          unsigned type, it doesn't matter whether we
2045                          pass it as signed or unsigned; the value
2046                          certainly is the same either way.  */
2047                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2048                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2049                         ;
2050                       else if (TYPE_UNSIGNED (type))
2051                         warn_for_assignment ("%s as unsigned due to prototype", (char *) 0, name, parmnum + 1);
2052                       else
2053                         warn_for_assignment ("%s as signed due to prototype", (char *) 0, name, parmnum + 1);
2054                     }
2055                 }
2056
2057               parmval = convert_for_assignment (type, val,
2058                                                 (char *) 0, /* arg passing  */
2059                                                 fundecl, name, parmnum + 1);
2060
2061               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2062                   && INTEGRAL_TYPE_P (type)
2063                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2064                 parmval = default_conversion (parmval);
2065             }
2066           result = tree_cons (NULL_TREE, parmval, result);
2067         }
2068       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2069                && (TYPE_PRECISION (TREE_TYPE (val))
2070                    < TYPE_PRECISION (double_type_node)))
2071         /* Convert `float' to `double'.  */
2072         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2073       else
2074         /* Convert `short' and `char' to full-size `int'.  */
2075         result = tree_cons (NULL_TREE, default_conversion (val), result);
2076
2077       if (typetail)
2078         typetail = TREE_CHAIN (typetail);
2079     }
2080
2081   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2082     {
2083       if (name)
2084         error ("too few arguments to function `%s'",
2085                IDENTIFIER_POINTER (name));
2086       else
2087         error ("too few arguments to function");
2088     }
2089
2090   return nreverse (result);
2091 }
2092 \f
2093 /* This is the entry point used by the parser
2094    for binary operators in the input.
2095    In addition to constructing the expression,
2096    we check for operands that were written with other binary operators
2097    in a way that is likely to confuse the user.  */
2098
2099 struct c_expr
2100 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2101                         struct c_expr arg2)
2102 {
2103   struct c_expr result;
2104
2105   enum tree_code code1 = arg1.original_code;
2106   enum tree_code code2 = arg2.original_code;
2107
2108   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2109   result.original_code = code;
2110
2111   if (TREE_CODE (result.value) == ERROR_MARK)
2112     return result;
2113
2114   /* Check for cases such as x+y<<z which users are likely
2115      to misinterpret.  */
2116   if (warn_parentheses)
2117     {
2118       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2119         {
2120           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2121               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2122             warning ("suggest parentheses around + or - inside shift");
2123         }
2124
2125       if (code == TRUTH_ORIF_EXPR)
2126         {
2127           if (code1 == TRUTH_ANDIF_EXPR
2128               || code2 == TRUTH_ANDIF_EXPR)
2129             warning ("suggest parentheses around && within ||");
2130         }
2131
2132       if (code == BIT_IOR_EXPR)
2133         {
2134           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2135               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2136               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2137               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2138             warning ("suggest parentheses around arithmetic in operand of |");
2139           /* Check cases like x|y==z */
2140           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2141             warning ("suggest parentheses around comparison in operand of |");
2142         }
2143
2144       if (code == BIT_XOR_EXPR)
2145         {
2146           if (code1 == BIT_AND_EXPR
2147               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2148               || code2 == BIT_AND_EXPR
2149               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2150             warning ("suggest parentheses around arithmetic in operand of ^");
2151           /* Check cases like x^y==z */
2152           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2153             warning ("suggest parentheses around comparison in operand of ^");
2154         }
2155
2156       if (code == BIT_AND_EXPR)
2157         {
2158           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2159               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2160             warning ("suggest parentheses around + or - in operand of &");
2161           /* Check cases like x&y==z */
2162           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2163             warning ("suggest parentheses around comparison in operand of &");
2164         }
2165       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2166       if (TREE_CODE_CLASS (code) == '<'
2167           && (TREE_CODE_CLASS (code1) == '<'
2168               || TREE_CODE_CLASS (code2) == '<'))
2169         warning ("comparisons like X<=Y<=Z do not have their mathematical meaning");
2170
2171     }
2172
2173   unsigned_conversion_warning (result.value, arg1.value);
2174   unsigned_conversion_warning (result.value, arg2.value);
2175   overflow_warning (result.value);
2176
2177   return result;
2178 }
2179 \f
2180 /* Return a tree for the difference of pointers OP0 and OP1.
2181    The resulting tree has type int.  */
2182
2183 static tree
2184 pointer_diff (tree op0, tree op1)
2185 {
2186   tree restype = ptrdiff_type_node;
2187
2188   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2189   tree con0, con1, lit0, lit1;
2190   tree orig_op1 = op1;
2191
2192   if (pedantic || warn_pointer_arith)
2193     {
2194       if (TREE_CODE (target_type) == VOID_TYPE)
2195         pedwarn ("pointer of type `void *' used in subtraction");
2196       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2197         pedwarn ("pointer to a function used in subtraction");
2198     }
2199
2200   /* If the conversion to ptrdiff_type does anything like widening or
2201      converting a partial to an integral mode, we get a convert_expression
2202      that is in the way to do any simplifications.
2203      (fold-const.c doesn't know that the extra bits won't be needed.
2204      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2205      different mode in place.)
2206      So first try to find a common term here 'by hand'; we want to cover
2207      at least the cases that occur in legal static initializers.  */
2208   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2209   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2210
2211   if (TREE_CODE (con0) == PLUS_EXPR)
2212     {
2213       lit0 = TREE_OPERAND (con0, 1);
2214       con0 = TREE_OPERAND (con0, 0);
2215     }
2216   else
2217     lit0 = integer_zero_node;
2218
2219   if (TREE_CODE (con1) == PLUS_EXPR)
2220     {
2221       lit1 = TREE_OPERAND (con1, 1);
2222       con1 = TREE_OPERAND (con1, 0);
2223     }
2224   else
2225     lit1 = integer_zero_node;
2226
2227   if (operand_equal_p (con0, con1, 0))
2228     {
2229       op0 = lit0;
2230       op1 = lit1;
2231     }
2232
2233
2234   /* First do the subtraction as integers;
2235      then drop through to build the divide operator.
2236      Do not do default conversions on the minus operator
2237      in case restype is a short type.  */
2238
2239   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2240                          convert (restype, op1), 0);
2241   /* This generates an error if op1 is pointer to incomplete type.  */
2242   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2243     error ("arithmetic on pointer to an incomplete type");
2244
2245   /* This generates an error if op0 is pointer to incomplete type.  */
2246   op1 = c_size_in_bytes (target_type);
2247
2248   /* Divide by the size, in easiest possible way.  */
2249   return fold (build (EXACT_DIV_EXPR, restype, op0, convert (restype, op1)));
2250 }
2251 \f
2252 /* Construct and perhaps optimize a tree representation
2253    for a unary operation.  CODE, a tree_code, specifies the operation
2254    and XARG is the operand.
2255    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2256    the default promotions (such as from short to int).
2257    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2258    allows non-lvalues; this is only used to handle conversion of non-lvalue
2259    arrays to pointers in C99.  */
2260
2261 tree
2262 build_unary_op (enum tree_code code, tree xarg, int flag)
2263 {
2264   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2265   tree arg = xarg;
2266   tree argtype = 0;
2267   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2268   tree val;
2269   int noconvert = flag;
2270
2271   if (typecode == ERROR_MARK)
2272     return error_mark_node;
2273   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2274     typecode = INTEGER_TYPE;
2275
2276   switch (code)
2277     {
2278     case CONVERT_EXPR:
2279       /* This is used for unary plus, because a CONVERT_EXPR
2280          is enough to prevent anybody from looking inside for
2281          associativity, but won't generate any code.  */
2282       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2283             || typecode == COMPLEX_TYPE
2284             || typecode == VECTOR_TYPE))
2285         {
2286           error ("wrong type argument to unary plus");
2287           return error_mark_node;
2288         }
2289       else if (!noconvert)
2290         arg = default_conversion (arg);
2291       arg = non_lvalue (arg);
2292       break;
2293
2294     case NEGATE_EXPR:
2295       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2296             || typecode == COMPLEX_TYPE
2297             || typecode == VECTOR_TYPE))
2298         {
2299           error ("wrong type argument to unary minus");
2300           return error_mark_node;
2301         }
2302       else if (!noconvert)
2303         arg = default_conversion (arg);
2304       break;
2305
2306     case BIT_NOT_EXPR:
2307       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2308         {
2309           if (!noconvert)
2310             arg = default_conversion (arg);
2311         }
2312       else if (typecode == COMPLEX_TYPE)
2313         {
2314           code = CONJ_EXPR;
2315           if (pedantic)
2316             pedwarn ("ISO C does not support `~' for complex conjugation");
2317           if (!noconvert)
2318             arg = default_conversion (arg);
2319         }
2320       else
2321         {
2322           error ("wrong type argument to bit-complement");
2323           return error_mark_node;
2324         }
2325       break;
2326
2327     case ABS_EXPR:
2328       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2329         {
2330           error ("wrong type argument to abs");
2331           return error_mark_node;
2332         }
2333       else if (!noconvert)
2334         arg = default_conversion (arg);
2335       break;
2336
2337     case CONJ_EXPR:
2338       /* Conjugating a real value is a no-op, but allow it anyway.  */
2339       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2340             || typecode == COMPLEX_TYPE))
2341         {
2342           error ("wrong type argument to conjugation");
2343           return error_mark_node;
2344         }
2345       else if (!noconvert)
2346         arg = default_conversion (arg);
2347       break;
2348
2349     case TRUTH_NOT_EXPR:
2350       if (typecode != INTEGER_TYPE
2351           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2352           && typecode != COMPLEX_TYPE
2353           /* These will convert to a pointer.  */
2354           && typecode != ARRAY_TYPE && typecode != FUNCTION_TYPE)
2355         {
2356           error ("wrong type argument to unary exclamation mark");
2357           return error_mark_node;
2358         }
2359       arg = lang_hooks.truthvalue_conversion (arg);
2360       return invert_truthvalue (arg);
2361
2362     case NOP_EXPR:
2363       break;
2364
2365     case REALPART_EXPR:
2366       if (TREE_CODE (arg) == COMPLEX_CST)
2367         return TREE_REALPART (arg);
2368       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2369         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2370       else
2371         return arg;
2372
2373     case IMAGPART_EXPR:
2374       if (TREE_CODE (arg) == COMPLEX_CST)
2375         return TREE_IMAGPART (arg);
2376       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2377         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2378       else
2379         return convert (TREE_TYPE (arg), integer_zero_node);
2380
2381     case PREINCREMENT_EXPR:
2382     case POSTINCREMENT_EXPR:
2383     case PREDECREMENT_EXPR:
2384     case POSTDECREMENT_EXPR:
2385
2386       /* Increment or decrement the real part of the value,
2387          and don't change the imaginary part.  */
2388       if (typecode == COMPLEX_TYPE)
2389         {
2390           tree real, imag;
2391
2392           if (pedantic)
2393             pedwarn ("ISO C does not support `++' and `--' on complex types");
2394
2395           arg = stabilize_reference (arg);
2396           real = build_unary_op (REALPART_EXPR, arg, 1);
2397           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2398           return build (COMPLEX_EXPR, TREE_TYPE (arg),
2399                         build_unary_op (code, real, 1), imag);
2400         }
2401
2402       /* Report invalid types.  */
2403
2404       if (typecode != POINTER_TYPE
2405           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2406         {
2407           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2408             error ("wrong type argument to increment");
2409           else
2410             error ("wrong type argument to decrement");
2411
2412           return error_mark_node;
2413         }
2414
2415       {
2416         tree inc;
2417         tree result_type = TREE_TYPE (arg);
2418
2419         arg = get_unwidened (arg, 0);
2420         argtype = TREE_TYPE (arg);
2421
2422         /* Compute the increment.  */
2423
2424         if (typecode == POINTER_TYPE)
2425           {
2426             /* If pointer target is an undefined struct,
2427                we just cannot know how to do the arithmetic.  */
2428             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2429               {
2430                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2431                   error ("increment of pointer to unknown structure");
2432                 else
2433                   error ("decrement of pointer to unknown structure");
2434               }
2435             else if ((pedantic || warn_pointer_arith)
2436                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2437                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2438               {
2439                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2440                   pedwarn ("wrong type argument to increment");
2441                 else
2442                   pedwarn ("wrong type argument to decrement");
2443               }
2444
2445             inc = c_size_in_bytes (TREE_TYPE (result_type));
2446           }
2447         else
2448           inc = integer_one_node;
2449
2450         inc = convert (argtype, inc);
2451
2452         /* Complain about anything else that is not a true lvalue.  */
2453         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2454                                     || code == POSTINCREMENT_EXPR)
2455                                    ? "invalid lvalue in increment"
2456                                    : "invalid lvalue in decrement")))
2457           return error_mark_node;
2458
2459         /* Report a read-only lvalue.  */
2460         if (TREE_READONLY (arg))
2461           readonly_error (arg,
2462                           ((code == PREINCREMENT_EXPR
2463                             || code == POSTINCREMENT_EXPR)
2464                            ? "increment" : "decrement"));
2465
2466         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2467           val = boolean_increment (code, arg);
2468         else
2469           val = build (code, TREE_TYPE (arg), arg, inc);
2470         TREE_SIDE_EFFECTS (val) = 1;
2471         val = convert (result_type, val);
2472         if (TREE_CODE (val) != code)
2473           TREE_NO_WARNING (val) = 1;
2474         return val;
2475       }
2476
2477     case ADDR_EXPR:
2478       /* Note that this operation never does default_conversion.  */
2479
2480       /* Let &* cancel out to simplify resulting code.  */
2481       if (TREE_CODE (arg) == INDIRECT_REF)
2482         {
2483           /* Don't let this be an lvalue.  */
2484           if (lvalue_p (TREE_OPERAND (arg, 0)))
2485             return non_lvalue (TREE_OPERAND (arg, 0));
2486           return TREE_OPERAND (arg, 0);
2487         }
2488
2489       /* For &x[y], return x+y */
2490       if (TREE_CODE (arg) == ARRAY_REF)
2491         {
2492           if (!c_mark_addressable (TREE_OPERAND (arg, 0)))
2493             return error_mark_node;
2494           return build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
2495                                   TREE_OPERAND (arg, 1), 1);
2496         }
2497
2498       /* Anything not already handled and not a true memory reference
2499          or a non-lvalue array is an error.  */
2500       else if (typecode != FUNCTION_TYPE && !flag
2501                && !lvalue_or_else (arg, "invalid lvalue in unary `&'"))
2502         return error_mark_node;
2503
2504       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2505       argtype = TREE_TYPE (arg);
2506
2507       /* If the lvalue is const or volatile, merge that into the type
2508          to which the address will point.  Note that you can't get a
2509          restricted pointer by taking the address of something, so we
2510          only have to deal with `const' and `volatile' here.  */
2511       if ((DECL_P (arg) || TREE_CODE_CLASS (TREE_CODE (arg)) == 'r')
2512           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2513           argtype = c_build_type_variant (argtype,
2514                                           TREE_READONLY (arg),
2515                                           TREE_THIS_VOLATILE (arg));
2516
2517       argtype = build_pointer_type (argtype);
2518
2519       if (!c_mark_addressable (arg))
2520         return error_mark_node;
2521
2522       {
2523         tree addr;
2524
2525         if (TREE_CODE (arg) == COMPONENT_REF)
2526           {
2527             tree field = TREE_OPERAND (arg, 1);
2528
2529             addr = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), flag);
2530
2531             if (DECL_C_BIT_FIELD (field))
2532               {
2533                 error ("attempt to take address of bit-field structure member `%s'",
2534                        IDENTIFIER_POINTER (DECL_NAME (field)));
2535                 return error_mark_node;
2536               }
2537
2538             addr = fold (build (PLUS_EXPR, argtype,
2539                                 convert (argtype, addr),
2540                                 convert (argtype, byte_position (field))));
2541           }
2542         else
2543           addr = build1 (code, argtype, arg);
2544
2545         if (TREE_CODE (arg) == COMPOUND_LITERAL_EXPR)
2546           TREE_INVARIANT (addr) = TREE_CONSTANT (addr) = 1;
2547
2548         return addr;
2549       }
2550
2551     default:
2552       break;
2553     }
2554
2555   if (argtype == 0)
2556     argtype = TREE_TYPE (arg);
2557   val = build1 (code, argtype, arg);
2558   return require_constant_value ? fold_initializer (val) : fold (val);
2559 }
2560
2561 /* Return nonzero if REF is an lvalue valid for this language.
2562    Lvalues can be assigned, unless their type has TYPE_READONLY.
2563    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2564
2565 int
2566 lvalue_p (tree ref)
2567 {
2568   enum tree_code code = TREE_CODE (ref);
2569
2570   switch (code)
2571     {
2572     case REALPART_EXPR:
2573     case IMAGPART_EXPR:
2574     case COMPONENT_REF:
2575       return lvalue_p (TREE_OPERAND (ref, 0));
2576
2577     case COMPOUND_LITERAL_EXPR:
2578     case STRING_CST:
2579       return 1;
2580
2581     case INDIRECT_REF:
2582     case ARRAY_REF:
2583     case VAR_DECL:
2584     case PARM_DECL:
2585     case RESULT_DECL:
2586     case ERROR_MARK:
2587       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2588               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2589
2590     case BIND_EXPR:
2591       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2592
2593     default:
2594       return 0;
2595     }
2596 }
2597
2598 /* Return nonzero if REF is an lvalue valid for this language;
2599    otherwise, print an error message and return zero.  */
2600
2601 static int
2602 lvalue_or_else (tree ref, const char *msgid)
2603 {
2604   int win = lvalue_p (ref);
2605
2606   if (! win)
2607     error ("%s", msgid);
2608
2609   return win;
2610 }
2611
2612 \f
2613 /* Warn about storing in something that is `const'.  */
2614
2615 void
2616 readonly_error (tree arg, const char *msgid)
2617 {
2618   if (TREE_CODE (arg) == COMPONENT_REF)
2619     {
2620       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2621         readonly_error (TREE_OPERAND (arg, 0), msgid);
2622       else
2623         error ("%s of read-only member `%s'", _(msgid),
2624                IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (arg, 1))));
2625     }
2626   else if (TREE_CODE (arg) == VAR_DECL)
2627     error ("%s of read-only variable `%s'", _(msgid),
2628            IDENTIFIER_POINTER (DECL_NAME (arg)));
2629   else
2630     error ("%s of read-only location", _(msgid));
2631 }
2632 \f
2633 /* Mark EXP saying that we need to be able to take the
2634    address of it; it should not be allocated in a register.
2635    Returns true if successful.  */
2636
2637 bool
2638 c_mark_addressable (tree exp)
2639 {
2640   tree x = exp;
2641
2642   while (1)
2643     switch (TREE_CODE (x))
2644       {
2645       case COMPONENT_REF:
2646         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2647           {
2648             error ("cannot take address of bit-field `%s'",
2649                    IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (x, 1))));
2650             return false;
2651           }
2652
2653         /* ... fall through ...  */
2654
2655       case ADDR_EXPR:
2656       case ARRAY_REF:
2657       case REALPART_EXPR:
2658       case IMAGPART_EXPR:
2659         x = TREE_OPERAND (x, 0);
2660         break;
2661
2662       case COMPOUND_LITERAL_EXPR:
2663       case CONSTRUCTOR:
2664         TREE_ADDRESSABLE (x) = 1;
2665         return true;
2666
2667       case VAR_DECL:
2668       case CONST_DECL:
2669       case PARM_DECL:
2670       case RESULT_DECL:
2671         if (C_DECL_REGISTER (x)
2672             && DECL_NONLOCAL (x))
2673           {
2674             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2675               {
2676                 error ("global register variable `%s' used in nested function",
2677                        IDENTIFIER_POINTER (DECL_NAME (x)));
2678                 return false;
2679               }
2680             pedwarn ("register variable `%s' used in nested function",
2681                      IDENTIFIER_POINTER (DECL_NAME (x)));
2682           }
2683         else if (C_DECL_REGISTER (x))
2684           {
2685             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2686               {
2687                 error ("address of global register variable `%s' requested",
2688                        IDENTIFIER_POINTER (DECL_NAME (x)));
2689                 return false;
2690               }
2691
2692             pedwarn ("address of register variable `%s' requested",
2693                      IDENTIFIER_POINTER (DECL_NAME (x)));
2694           }
2695
2696         /* drops in */
2697       case FUNCTION_DECL:
2698         TREE_ADDRESSABLE (x) = 1;
2699         /* drops out */
2700       default:
2701         return true;
2702     }
2703 }
2704 \f
2705 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2706
2707 tree
2708 build_conditional_expr (tree ifexp, tree op1, tree op2)
2709 {
2710   tree type1;
2711   tree type2;
2712   enum tree_code code1;
2713   enum tree_code code2;
2714   tree result_type = NULL;
2715   tree orig_op1 = op1, orig_op2 = op2;
2716
2717   ifexp = lang_hooks.truthvalue_conversion (default_conversion (ifexp));
2718
2719   /* Promote both alternatives.  */
2720
2721   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2722     op1 = default_conversion (op1);
2723   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2724     op2 = default_conversion (op2);
2725
2726   if (TREE_CODE (ifexp) == ERROR_MARK
2727       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2728       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2729     return error_mark_node;
2730
2731   type1 = TREE_TYPE (op1);
2732   code1 = TREE_CODE (type1);
2733   type2 = TREE_TYPE (op2);
2734   code2 = TREE_CODE (type2);
2735
2736   /* C90 does not permit non-lvalue arrays in conditional expressions.
2737      In C99 they will be pointers by now.  */
2738   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2739     {
2740       error ("non-lvalue array in conditional expression");
2741       return error_mark_node;
2742     }
2743
2744   /* Quickly detect the usual case where op1 and op2 have the same type
2745      after promotion.  */
2746   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2747     {
2748       if (type1 == type2)
2749         result_type = type1;
2750       else
2751         result_type = TYPE_MAIN_VARIANT (type1);
2752     }
2753   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
2754             || code1 == COMPLEX_TYPE)
2755            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
2756                || code2 == COMPLEX_TYPE))
2757     {
2758       result_type = common_type (type1, type2);
2759
2760       /* If -Wsign-compare, warn here if type1 and type2 have
2761          different signedness.  We'll promote the signed to unsigned
2762          and later code won't know it used to be different.
2763          Do this check on the original types, so that explicit casts
2764          will be considered, but default promotions won't.  */
2765       if (warn_sign_compare && !skip_evaluation)
2766         {
2767           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
2768           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
2769
2770           if (unsigned_op1 ^ unsigned_op2)
2771             {
2772               /* Do not warn if the result type is signed, since the
2773                  signed type will only be chosen if it can represent
2774                  all the values of the unsigned type.  */
2775               if (! TYPE_UNSIGNED (result_type))
2776                 /* OK */;
2777               /* Do not warn if the signed quantity is an unsuffixed
2778                  integer literal (or some static constant expression
2779                  involving such literals) and it is non-negative.  */
2780               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
2781                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
2782                 /* OK */;
2783               else
2784                 warning ("signed and unsigned type in conditional expression");
2785             }
2786         }
2787     }
2788   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
2789     {
2790       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
2791         pedwarn ("ISO C forbids conditional expr with only one void side");
2792       result_type = void_type_node;
2793     }
2794   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
2795     {
2796       if (comp_target_types (type1, type2, 1))
2797         result_type = common_pointer_type (type1, type2);
2798       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
2799                && TREE_CODE (orig_op1) != NOP_EXPR)
2800         result_type = qualify_type (type2, type1);
2801       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
2802                && TREE_CODE (orig_op2) != NOP_EXPR)
2803         result_type = qualify_type (type1, type2);
2804       else if (VOID_TYPE_P (TREE_TYPE (type1)))
2805         {
2806           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
2807             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2808           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
2809                                                           TREE_TYPE (type2)));
2810         }
2811       else if (VOID_TYPE_P (TREE_TYPE (type2)))
2812         {
2813           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
2814             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2815           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
2816                                                           TREE_TYPE (type1)));
2817         }
2818       else
2819         {
2820           pedwarn ("pointer type mismatch in conditional expression");
2821           result_type = build_pointer_type (void_type_node);
2822         }
2823     }
2824   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
2825     {
2826       if (! integer_zerop (op2))
2827         pedwarn ("pointer/integer type mismatch in conditional expression");
2828       else
2829         {
2830           op2 = null_pointer_node;
2831         }
2832       result_type = type1;
2833     }
2834   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
2835     {
2836       if (!integer_zerop (op1))
2837         pedwarn ("pointer/integer type mismatch in conditional expression");
2838       else
2839         {
2840           op1 = null_pointer_node;
2841         }
2842       result_type = type2;
2843     }
2844
2845   if (!result_type)
2846     {
2847       if (flag_cond_mismatch)
2848         result_type = void_type_node;
2849       else
2850         {
2851           error ("type mismatch in conditional expression");
2852           return error_mark_node;
2853         }
2854     }
2855
2856   /* Merge const and volatile flags of the incoming types.  */
2857   result_type
2858     = build_type_variant (result_type,
2859                           TREE_READONLY (op1) || TREE_READONLY (op2),
2860                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
2861
2862   if (result_type != TREE_TYPE (op1))
2863     op1 = convert_and_check (result_type, op1);
2864   if (result_type != TREE_TYPE (op2))
2865     op2 = convert_and_check (result_type, op2);
2866
2867   if (TREE_CODE (ifexp) == INTEGER_CST)
2868     return non_lvalue (integer_zerop (ifexp) ? op2 : op1);
2869
2870   return fold (build (COND_EXPR, result_type, ifexp, op1, op2));
2871 }
2872 \f
2873 /* Return a compound expression that performs two expressions and
2874    returns the value of the second of them.  */
2875
2876 tree
2877 build_compound_expr (tree expr1, tree expr2)
2878 {
2879   /* Convert arrays and functions to pointers.  */
2880   expr2 = default_function_array_conversion (expr2);
2881
2882   /* Don't let (0, 0) be null pointer constant.  */
2883   if (integer_zerop (expr2))
2884     expr2 = non_lvalue (expr2);
2885
2886   if (! TREE_SIDE_EFFECTS (expr1))
2887     {
2888       /* The left-hand operand of a comma expression is like an expression
2889          statement: with -Wextra or -Wunused, we should warn if it doesn't have
2890          any side-effects, unless it was explicitly cast to (void).  */
2891       if (warn_unused_value
2892            && ! (TREE_CODE (expr1) == CONVERT_EXPR
2893                 && VOID_TYPE_P (TREE_TYPE (expr1))))
2894         warning ("left-hand operand of comma expression has no effect");
2895     }
2896
2897   /* With -Wunused, we should also warn if the left-hand operand does have
2898      side-effects, but computes a value which is not used.  For example, in
2899      `foo() + bar(), baz()' the result of the `+' operator is not used,
2900      so we should issue a warning.  */
2901   else if (warn_unused_value)
2902     warn_if_unused_value (expr1, input_location);
2903
2904   return build (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
2905 }
2906
2907 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
2908
2909 tree
2910 build_c_cast (tree type, tree expr)
2911 {
2912   tree value = expr;
2913
2914   if (type == error_mark_node || expr == error_mark_node)
2915     return error_mark_node;
2916
2917   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
2918      only in <protocol> qualifications.  But when constructing cast expressions,
2919      the protocols do matter and must be kept around.  */
2920   if (!c_dialect_objc () || !objc_is_object_ptr (type))
2921     type = TYPE_MAIN_VARIANT (type);
2922
2923   if (TREE_CODE (type) == ARRAY_TYPE)
2924     {
2925       error ("cast specifies array type");
2926       return error_mark_node;
2927     }
2928
2929   if (TREE_CODE (type) == FUNCTION_TYPE)
2930     {
2931       error ("cast specifies function type");
2932       return error_mark_node;
2933     }
2934
2935   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
2936     {
2937       if (pedantic)
2938         {
2939           if (TREE_CODE (type) == RECORD_TYPE
2940               || TREE_CODE (type) == UNION_TYPE)
2941             pedwarn ("ISO C forbids casting nonscalar to the same type");
2942         }
2943     }
2944   else if (TREE_CODE (type) == UNION_TYPE)
2945     {
2946       tree field;
2947       value = default_function_array_conversion (value);
2948
2949       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
2950         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
2951                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
2952           break;
2953
2954       if (field)
2955         {
2956           tree t;
2957
2958           if (pedantic)
2959             pedwarn ("ISO C forbids casts to union type");
2960           t = digest_init (type,
2961                            build_constructor (type,
2962                                               build_tree_list (field, value)),
2963                            true, 0);
2964           TREE_CONSTANT (t) = TREE_CONSTANT (value);
2965           TREE_INVARIANT (t) = TREE_INVARIANT (value);
2966           return t;
2967         }
2968       error ("cast to union type from type not present in union");
2969       return error_mark_node;
2970     }
2971   else
2972     {
2973       tree otype, ovalue;
2974
2975       /* If casting to void, avoid the error that would come
2976          from default_conversion in the case of a non-lvalue array.  */
2977       if (type == void_type_node)
2978         return build1 (CONVERT_EXPR, type, value);
2979
2980       /* Convert functions and arrays to pointers,
2981          but don't convert any other types.  */
2982       value = default_function_array_conversion (value);
2983       otype = TREE_TYPE (value);
2984
2985       /* Optionally warn about potentially worrisome casts.  */
2986
2987       if (warn_cast_qual
2988           && TREE_CODE (type) == POINTER_TYPE
2989           && TREE_CODE (otype) == POINTER_TYPE)
2990         {
2991           tree in_type = type;
2992           tree in_otype = otype;
2993           int added = 0;
2994           int discarded = 0;
2995
2996           /* Check that the qualifiers on IN_TYPE are a superset of
2997              the qualifiers of IN_OTYPE.  The outermost level of
2998              POINTER_TYPE nodes is uninteresting and we stop as soon
2999              as we hit a non-POINTER_TYPE node on either type.  */
3000           do
3001             {
3002               in_otype = TREE_TYPE (in_otype);
3003               in_type = TREE_TYPE (in_type);
3004
3005               /* GNU C allows cv-qualified function types.  'const'
3006                  means the function is very pure, 'volatile' means it
3007                  can't return.  We need to warn when such qualifiers
3008                  are added, not when they're taken away.  */
3009               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3010                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3011                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3012               else
3013                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3014             }
3015           while (TREE_CODE (in_type) == POINTER_TYPE
3016                  && TREE_CODE (in_otype) == POINTER_TYPE);
3017
3018           if (added)
3019             warning ("cast adds new qualifiers to function type");
3020
3021           if (discarded)
3022             /* There are qualifiers present in IN_OTYPE that are not
3023                present in IN_TYPE.  */
3024             warning ("cast discards qualifiers from pointer target type");
3025         }
3026
3027       /* Warn about possible alignment problems.  */
3028       if (STRICT_ALIGNMENT && warn_cast_align
3029           && TREE_CODE (type) == POINTER_TYPE
3030           && TREE_CODE (otype) == POINTER_TYPE
3031           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3032           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3033           /* Don't warn about opaque types, where the actual alignment
3034              restriction is unknown.  */
3035           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3036                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3037                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3038           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3039         warning ("cast increases required alignment of target type");
3040
3041       if (TREE_CODE (type) == INTEGER_TYPE
3042           && TREE_CODE (otype) == POINTER_TYPE
3043           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3044           && !TREE_CONSTANT (value))
3045         warning ("cast from pointer to integer of different size");
3046
3047       if (warn_bad_function_cast
3048           && TREE_CODE (value) == CALL_EXPR
3049           && TREE_CODE (type) != TREE_CODE (otype))
3050         warning ("cast does not match function type");
3051
3052       if (TREE_CODE (type) == POINTER_TYPE
3053           && TREE_CODE (otype) == INTEGER_TYPE
3054           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3055           /* Don't warn about converting any constant.  */
3056           && !TREE_CONSTANT (value))
3057         warning ("cast to pointer from integer of different size");
3058
3059       if (TREE_CODE (type) == POINTER_TYPE
3060           && TREE_CODE (otype) == POINTER_TYPE
3061           && TREE_CODE (expr) == ADDR_EXPR
3062           && DECL_P (TREE_OPERAND (expr, 0))
3063           && flag_strict_aliasing && warn_strict_aliasing
3064           && !VOID_TYPE_P (TREE_TYPE (type)))
3065         {
3066           /* Casting the address of a decl to non void pointer. Warn
3067              if the cast breaks type based aliasing.  */
3068           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3069             warning ("type-punning to incomplete type might break strict-aliasing rules");
3070           else
3071             {
3072               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3073               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3074
3075               if (!alias_sets_conflict_p (set1, set2))
3076                 warning ("dereferencing type-punned pointer will break strict-aliasing rules");
3077               else if (warn_strict_aliasing > 1
3078                        && !alias_sets_might_conflict_p (set1, set2))
3079                 warning ("dereferencing type-punned pointer might break strict-aliasing rules");
3080             }
3081         }
3082
3083       /* If pedantic, warn for conversions between function and object
3084          pointer types, except for converting a null pointer constant
3085          to function pointer type.  */
3086       if (pedantic
3087           && TREE_CODE (type) == POINTER_TYPE
3088           && TREE_CODE (otype) == POINTER_TYPE
3089           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3090           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3091         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3092
3093       if (pedantic
3094           && TREE_CODE (type) == POINTER_TYPE
3095           && TREE_CODE (otype) == POINTER_TYPE
3096           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3097           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3098           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3099                && TREE_CODE (expr) != NOP_EXPR))
3100         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3101
3102       ovalue = value;
3103       /* Replace a nonvolatile const static variable with its value.  */
3104       if (optimize && TREE_CODE (value) == VAR_DECL)
3105         value = decl_constant_value (value);
3106       value = convert (type, value);
3107
3108       /* Ignore any integer overflow caused by the cast.  */
3109       if (TREE_CODE (value) == INTEGER_CST)
3110         {
3111           TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3112
3113           if (TREE_CODE_CLASS (TREE_CODE (ovalue)) == 'c')
3114             TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3115         }
3116     }
3117
3118   /* Don't let (void *) (FOO *) 0 be a null pointer constant.  */
3119   if (TREE_CODE (value) == INTEGER_CST
3120       && TREE_CODE (expr) == INTEGER_CST
3121       && TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE)
3122     value = non_lvalue (value);
3123
3124   /* Don't let a cast be an lvalue.  */
3125   if (value == expr)
3126     value = non_lvalue (value);
3127
3128   return value;
3129 }
3130
3131 /* Interpret a cast of expression EXPR to type TYPE.  */
3132 tree
3133 c_cast_expr (tree type, tree expr)
3134 {
3135   int saved_wsp = warn_strict_prototypes;
3136
3137   /* This avoids warnings about unprototyped casts on
3138      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3139   if (TREE_CODE (expr) == INTEGER_CST)
3140     warn_strict_prototypes = 0;
3141   type = groktypename (type);
3142   warn_strict_prototypes = saved_wsp;
3143
3144   return build_c_cast (type, expr);
3145 }
3146
3147 \f
3148 /* Build an assignment expression of lvalue LHS from value RHS.
3149    MODIFYCODE is the code for a binary operator that we use
3150    to combine the old value of LHS with RHS to get the new value.
3151    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3152
3153 tree
3154 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3155 {
3156   tree result;
3157   tree newrhs;
3158   tree lhstype = TREE_TYPE (lhs);
3159   tree olhstype = lhstype;
3160
3161   /* Types that aren't fully specified cannot be used in assignments.  */
3162   lhs = require_complete_type (lhs);
3163
3164   /* Avoid duplicate error messages from operands that had errors.  */
3165   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3166     return error_mark_node;
3167
3168   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3169   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3170      whose value is 0 to count as a null pointer constant.  */
3171   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3172     rhs = TREE_OPERAND (rhs, 0);
3173
3174   newrhs = rhs;
3175
3176   /* If a binary op has been requested, combine the old LHS value with the RHS
3177      producing the value we should actually store into the LHS.  */
3178
3179   if (modifycode != NOP_EXPR)
3180     {
3181       lhs = stabilize_reference (lhs);
3182       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3183     }
3184
3185   if (!lvalue_or_else (lhs, "invalid lvalue in assignment"))
3186     return error_mark_node;
3187
3188   /* Warn about storing in something that is `const'.  */
3189
3190   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3191       || ((TREE_CODE (lhstype) == RECORD_TYPE
3192            || TREE_CODE (lhstype) == UNION_TYPE)
3193           && C_TYPE_FIELDS_READONLY (lhstype)))
3194     readonly_error (lhs, "assignment");
3195
3196   /* If storing into a structure or union member,
3197      it has probably been given type `int'.
3198      Compute the type that would go with
3199      the actual amount of storage the member occupies.  */
3200
3201   if (TREE_CODE (lhs) == COMPONENT_REF
3202       && (TREE_CODE (lhstype) == INTEGER_TYPE
3203           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3204           || TREE_CODE (lhstype) == REAL_TYPE
3205           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3206     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3207
3208   /* If storing in a field that is in actuality a short or narrower than one,
3209      we must store in the field in its actual type.  */
3210
3211   if (lhstype != TREE_TYPE (lhs))
3212     {
3213       lhs = copy_node (lhs);
3214       TREE_TYPE (lhs) = lhstype;
3215     }
3216
3217   /* Convert new value to destination type.  */
3218
3219   newrhs = convert_for_assignment (lhstype, newrhs, _("assignment"),
3220                                    NULL_TREE, NULL_TREE, 0);
3221   if (TREE_CODE (newrhs) == ERROR_MARK)
3222     return error_mark_node;
3223
3224   /* Scan operands */
3225
3226   result = build (MODIFY_EXPR, lhstype, lhs, newrhs);
3227   TREE_SIDE_EFFECTS (result) = 1;
3228
3229   /* If we got the LHS in a different type for storing in,
3230      convert the result back to the nominal type of LHS
3231      so that the value we return always has the same type
3232      as the LHS argument.  */
3233
3234   if (olhstype == TREE_TYPE (result))
3235     return result;
3236   return convert_for_assignment (olhstype, result, _("assignment"),
3237                                  NULL_TREE, NULL_TREE, 0);
3238 }
3239 \f
3240 /* Convert value RHS to type TYPE as preparation for an assignment
3241    to an lvalue of type TYPE.
3242    The real work of conversion is done by `convert'.
3243    The purpose of this function is to generate error messages
3244    for assignments that are not allowed in C.
3245    ERRTYPE is a string to use in error messages:
3246    "assignment", "return", etc.  If it is null, this is parameter passing
3247    for a function call (and different error messages are output).
3248
3249    FUNNAME is the name of the function being called,
3250    as an IDENTIFIER_NODE, or null.
3251    PARMNUM is the number of the argument, for printing in error messages.  */
3252
3253 static tree
3254 convert_for_assignment (tree type, tree rhs, const char *errtype,
3255                         tree fundecl, tree funname, int parmnum)
3256 {
3257   enum tree_code codel = TREE_CODE (type);
3258   tree rhstype;
3259   enum tree_code coder;
3260
3261   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3262   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3263      whose value is 0 to count as a null pointer constant.  */
3264   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3265     rhs = TREE_OPERAND (rhs, 0);
3266
3267   if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
3268       || TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE)
3269     rhs = default_conversion (rhs);
3270   else if (optimize && TREE_CODE (rhs) == VAR_DECL)
3271     rhs = decl_constant_value_for_broken_optimization (rhs);
3272
3273   rhstype = TREE_TYPE (rhs);
3274   coder = TREE_CODE (rhstype);
3275
3276   if (coder == ERROR_MARK)
3277     return error_mark_node;
3278
3279   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3280     {
3281       overflow_warning (rhs);
3282       /* Check for Objective-C protocols.  This will automatically
3283          issue a warning if there are protocol violations.  No need to
3284          use the return value.  */
3285       if (c_dialect_objc ())
3286         objc_comptypes (type, rhstype, 0);
3287       return rhs;
3288     }
3289
3290   if (coder == VOID_TYPE)
3291     {
3292       error ("void value not ignored as it ought to be");
3293       return error_mark_node;
3294     }
3295   /* A type converts to a reference to it.
3296      This code doesn't fully support references, it's just for the
3297      special case of va_start and va_copy.  */
3298   if (codel == REFERENCE_TYPE
3299       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3300     {
3301       if (!lvalue_p (rhs))
3302         {
3303           error ("cannot pass rvalue to reference parameter");
3304           return error_mark_node;
3305         }
3306       if (!c_mark_addressable (rhs))
3307         return error_mark_node;
3308       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3309
3310       /* We already know that these two types are compatible, but they
3311          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3312          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3313          likely to be va_list, a typedef to __builtin_va_list, which
3314          is different enough that it will cause problems later.  */
3315       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3316         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3317
3318       rhs = build1 (NOP_EXPR, type, rhs);
3319       return rhs;
3320     }
3321   /* Some types can interconvert without explicit casts.  */
3322   else if (codel == VECTOR_TYPE
3323            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3324     return convert (type, rhs);
3325   /* Arithmetic types all interconvert, and enum is treated like int.  */
3326   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3327             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3328             || codel == BOOLEAN_TYPE)
3329            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3330                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3331                || coder == BOOLEAN_TYPE))
3332     return convert_and_check (type, rhs);
3333
3334   /* Conversion to a transparent union from its member types.
3335      This applies only to function arguments.  */
3336   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type) && ! errtype)
3337     {
3338       tree memb_types;
3339       tree marginal_memb_type = 0;
3340
3341       for (memb_types = TYPE_FIELDS (type); memb_types;
3342            memb_types = TREE_CHAIN (memb_types))
3343         {
3344           tree memb_type = TREE_TYPE (memb_types);
3345
3346           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3347                          TYPE_MAIN_VARIANT (rhstype)))
3348             break;
3349
3350           if (TREE_CODE (memb_type) != POINTER_TYPE)
3351             continue;
3352
3353           if (coder == POINTER_TYPE)
3354             {
3355               tree ttl = TREE_TYPE (memb_type);
3356               tree ttr = TREE_TYPE (rhstype);
3357
3358               /* Any non-function converts to a [const][volatile] void *
3359                  and vice versa; otherwise, targets must be the same.
3360                  Meanwhile, the lhs target must have all the qualifiers of
3361                  the rhs.  */
3362               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3363                   || comp_target_types (memb_type, rhstype, 0))
3364                 {
3365                   /* If this type won't generate any warnings, use it.  */
3366                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3367                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3368                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3369                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3370                              == TYPE_QUALS (ttr))
3371                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3372                              == TYPE_QUALS (ttl))))
3373                     break;
3374
3375                   /* Keep looking for a better type, but remember this one.  */
3376                   if (! marginal_memb_type)
3377                     marginal_memb_type = memb_type;
3378                 }
3379             }
3380
3381           /* Can convert integer zero to any pointer type.  */
3382           if (integer_zerop (rhs)
3383               || (TREE_CODE (rhs) == NOP_EXPR
3384                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3385             {
3386               rhs = null_pointer_node;
3387               break;
3388             }
3389         }
3390
3391       if (memb_types || marginal_memb_type)
3392         {
3393           if (! memb_types)
3394             {
3395               /* We have only a marginally acceptable member type;
3396                  it needs a warning.  */
3397               tree ttl = TREE_TYPE (marginal_memb_type);
3398               tree ttr = TREE_TYPE (rhstype);
3399
3400               /* Const and volatile mean something different for function
3401                  types, so the usual warnings are not appropriate.  */
3402               if (TREE_CODE (ttr) == FUNCTION_TYPE
3403                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3404                 {
3405                   /* Because const and volatile on functions are
3406                      restrictions that say the function will not do
3407                      certain things, it is okay to use a const or volatile
3408                      function where an ordinary one is wanted, but not
3409                      vice-versa.  */
3410                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3411                     warn_for_assignment ("%s makes qualified function pointer from unqualified",
3412                                          errtype, funname, parmnum);
3413                 }
3414               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3415                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3416                                      errtype, funname,
3417                                      parmnum);
3418             }
3419
3420           if (pedantic && ! DECL_IN_SYSTEM_HEADER (fundecl))
3421             pedwarn ("ISO C prohibits argument conversion to union type");
3422
3423           return build1 (NOP_EXPR, type, rhs);
3424         }
3425     }
3426
3427   /* Conversions among pointers */
3428   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3429            && (coder == codel))
3430     {
3431       tree ttl = TREE_TYPE (type);
3432       tree ttr = TREE_TYPE (rhstype);
3433       bool is_opaque_pointer;
3434       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3435
3436       /* Opaque pointers are treated like void pointers.  */
3437       is_opaque_pointer = (targetm.vector_opaque_p (type)
3438                            || targetm.vector_opaque_p (rhstype))
3439         && TREE_CODE (ttl) == VECTOR_TYPE
3440         && TREE_CODE (ttr) == VECTOR_TYPE;
3441
3442       /* Any non-function converts to a [const][volatile] void *
3443          and vice versa; otherwise, targets must be the same.
3444          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3445       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3446           || (target_cmp = comp_target_types (type, rhstype, 0))
3447           || is_opaque_pointer
3448           || (c_common_unsigned_type (TYPE_MAIN_VARIANT (ttl))
3449               == c_common_unsigned_type (TYPE_MAIN_VARIANT (ttr))))
3450         {
3451           if (pedantic
3452               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3453                   ||
3454                   (VOID_TYPE_P (ttr)
3455                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3456                       which are not ANSI null ptr constants.  */
3457                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3458                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3459             warn_for_assignment ("ISO C forbids %s between function pointer and `void *'",
3460                                  errtype, funname, parmnum);
3461           /* Const and volatile mean something different for function types,
3462              so the usual warnings are not appropriate.  */
3463           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3464                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3465             {
3466               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3467                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3468                                      errtype, funname, parmnum);
3469               /* If this is not a case of ignoring a mismatch in signedness,
3470                  no warning.  */
3471               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3472                        || target_cmp)
3473                 ;
3474               /* If there is a mismatch, do warn.  */
3475               else
3476                 warn_for_assignment ("pointer targets in %s differ in signedness",
3477                                      errtype, funname, parmnum);
3478             }
3479           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3480                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3481             {
3482               /* Because const and volatile on functions are restrictions
3483                  that say the function will not do certain things,
3484                  it is okay to use a const or volatile function
3485                  where an ordinary one is wanted, but not vice-versa.  */
3486               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3487                 warn_for_assignment ("%s makes qualified function pointer from unqualified",
3488                                      errtype, funname, parmnum);
3489             }
3490         }
3491       else
3492         warn_for_assignment ("%s from incompatible pointer type",
3493                              errtype, funname, parmnum);
3494       return convert (type, rhs);
3495     }
3496   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3497     {
3498       error ("invalid use of non-lvalue array");
3499       return error_mark_node;
3500     }
3501   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3502     {
3503       /* An explicit constant 0 can convert to a pointer,
3504          or one that results from arithmetic, even including
3505          a cast to integer type.  */
3506       if (! (TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3507           &&
3508           ! (TREE_CODE (rhs) == NOP_EXPR
3509              && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3510              && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3511              && integer_zerop (TREE_OPERAND (rhs, 0))))
3512           warn_for_assignment ("%s makes pointer from integer without a cast",
3513                                errtype, funname, parmnum);
3514
3515       return convert (type, rhs);
3516     }
3517   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3518     {
3519       warn_for_assignment ("%s makes integer from pointer without a cast",
3520                            errtype, funname, parmnum);
3521       return convert (type, rhs);
3522     }
3523   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3524     return convert (type, rhs);
3525
3526   if (!errtype)
3527     {
3528       if (funname)
3529         {
3530           tree selector = objc_message_selector ();
3531
3532           if (selector && parmnum > 2)
3533             error ("incompatible type for argument %d of `%s'",
3534                    parmnum - 2, IDENTIFIER_POINTER (selector));
3535           else
3536             error ("incompatible type for argument %d of `%s'",
3537                    parmnum, IDENTIFIER_POINTER (funname));
3538         }
3539       else
3540         error ("incompatible type for argument %d of indirect function call",
3541                parmnum);
3542     }
3543   else
3544     error ("incompatible types in %s", errtype);
3545
3546   return error_mark_node;
3547 }
3548
3549 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3550    is used for error and waring reporting and indicates which argument
3551    is being processed.  */
3552
3553 tree
3554 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3555 {
3556   tree ret, type;
3557
3558   /* If FN was prototyped, the value has been converted already
3559      in convert_arguments.  */
3560   if (! value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3561     return value;
3562
3563   type = TREE_TYPE (parm);
3564   ret = convert_for_assignment (type, value,
3565                                 (char *) 0 /* arg passing  */, fn,
3566                                 DECL_NAME (fn), argnum);
3567   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3568       && INTEGRAL_TYPE_P (type)
3569       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3570     ret = default_conversion (ret);
3571   return ret;
3572 }
3573
3574 /* Print a warning using MSGID.
3575    It gets OPNAME as its one parameter.
3576    if OPNAME is null and ARGNUM is 0, it is replaced by "passing arg of `FUNCTION'".
3577    Otherwise if OPNAME is null, it is replaced by "passing arg ARGNUM of `FUNCTION'".
3578    FUNCTION and ARGNUM are handled specially if we are building an
3579    Objective-C selector.  */
3580
3581 static void
3582 warn_for_assignment (const char *msgid, const char *opname, tree function,
3583                      int argnum)
3584 {
3585   if (opname == 0)
3586     {
3587       tree selector = objc_message_selector ();
3588       char * new_opname;
3589
3590       if (selector && argnum > 2)
3591         {
3592           function = selector;
3593           argnum -= 2;
3594         }
3595       if (argnum == 0)
3596         {
3597           if (function)
3598             {
3599               /* Function name is known; supply it.  */
3600               const char *const argstring = _("passing arg of `%s'");
3601               new_opname = alloca (IDENTIFIER_LENGTH (function)
3602                                    + strlen (argstring) + 1 + 1);
3603               sprintf (new_opname, argstring,
3604                        IDENTIFIER_POINTER (function));
3605             }
3606           else
3607             {
3608               /* Function name unknown (call through ptr).  */
3609               const char *const argnofun = _("passing arg of pointer to function");
3610               new_opname = alloca (strlen (argnofun) + 1 + 1);
3611               sprintf (new_opname, argnofun);
3612             }
3613         }
3614       else if (function)
3615         {
3616           /* Function name is known; supply it.  */
3617           const char *const argstring = _("passing arg %d of `%s'");
3618           new_opname = alloca (IDENTIFIER_LENGTH (function)
3619                                + strlen (argstring) + 1 + 25 /*%d*/ + 1);
3620           sprintf (new_opname, argstring, argnum,
3621                    IDENTIFIER_POINTER (function));
3622         }
3623       else
3624         {
3625           /* Function name unknown (call through ptr); just give arg number.  */
3626           const char *const argnofun = _("passing arg %d of pointer to function");
3627           new_opname = alloca (strlen (argnofun) + 1 + 25 /*%d*/ + 1);
3628           sprintf (new_opname, argnofun, argnum);
3629         }
3630       opname = new_opname;
3631     }
3632   pedwarn (msgid, opname);
3633 }
3634 \f
3635 /* If VALUE is a compound expr all of whose expressions are constant, then
3636    return its value.  Otherwise, return error_mark_node.
3637
3638    This is for handling COMPOUND_EXPRs as initializer elements
3639    which is allowed with a warning when -pedantic is specified.  */
3640
3641 static tree
3642 valid_compound_expr_initializer (tree value, tree endtype)
3643 {
3644   if (TREE_CODE (value) == COMPOUND_EXPR)
3645     {
3646       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3647           == error_mark_node)
3648         return error_mark_node;
3649       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3650                                               endtype);
3651     }
3652   else if (! TREE_CONSTANT (value)
3653            && ! initializer_constant_valid_p (value, endtype))
3654     return error_mark_node;
3655   else
3656     return value;
3657 }
3658 \f
3659 /* Perform appropriate conversions on the initial value of a variable,
3660    store it in the declaration DECL,
3661    and print any error messages that are appropriate.
3662    If the init is invalid, store an ERROR_MARK.  */
3663
3664 void
3665 store_init_value (tree decl, tree init)
3666 {
3667   tree value, type;
3668
3669   /* If variable's type was invalidly declared, just ignore it.  */
3670
3671   type = TREE_TYPE (decl);
3672   if (TREE_CODE (type) == ERROR_MARK)
3673     return;
3674
3675   /* Digest the specified initializer into an expression.  */
3676
3677   value = digest_init (type, init, true, TREE_STATIC (decl));
3678
3679   /* Store the expression if valid; else report error.  */
3680
3681   if (warn_traditional && !in_system_header
3682       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && ! TREE_STATIC (decl))
3683     warning ("traditional C rejects automatic aggregate initialization");
3684
3685   DECL_INITIAL (decl) = value;
3686
3687   /* ANSI wants warnings about out-of-range constant initializers.  */
3688   STRIP_TYPE_NOPS (value);
3689   constant_expression_warning (value);
3690
3691   /* Check if we need to set array size from compound literal size.  */
3692   if (TREE_CODE (type) == ARRAY_TYPE
3693       && TYPE_DOMAIN (type) == 0
3694       && value != error_mark_node)
3695     {
3696       tree inside_init = init;
3697
3698       if (TREE_CODE (init) == NON_LVALUE_EXPR)
3699         inside_init = TREE_OPERAND (init, 0);
3700       inside_init = fold (inside_init);
3701
3702       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
3703         {
3704           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
3705
3706           if (TYPE_DOMAIN (TREE_TYPE (decl)))
3707             {
3708               /* For int foo[] = (int [3]){1}; we need to set array size
3709                  now since later on array initializer will be just the
3710                  brace enclosed list of the compound literal.  */
3711               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
3712               layout_type (type);
3713               layout_decl (decl, 0);
3714             }
3715         }
3716     }
3717 }
3718 \f
3719 /* Methods for storing and printing names for error messages.  */
3720
3721 /* Implement a spelling stack that allows components of a name to be pushed
3722    and popped.  Each element on the stack is this structure.  */
3723
3724 struct spelling
3725 {
3726   int kind;
3727   union
3728     {
3729       int i;
3730       const char *s;
3731     } u;
3732 };
3733
3734 #define SPELLING_STRING 1
3735 #define SPELLING_MEMBER 2
3736 #define SPELLING_BOUNDS 3
3737
3738 static struct spelling *spelling;       /* Next stack element (unused).  */
3739 static struct spelling *spelling_base;  /* Spelling stack base.  */
3740 static int spelling_size;               /* Size of the spelling stack.  */
3741
3742 /* Macros to save and restore the spelling stack around push_... functions.
3743    Alternative to SAVE_SPELLING_STACK.  */
3744
3745 #define SPELLING_DEPTH() (spelling - spelling_base)
3746 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
3747
3748 /* Push an element on the spelling stack with type KIND and assign VALUE
3749    to MEMBER.  */
3750
3751 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
3752 {                                                                       \
3753   int depth = SPELLING_DEPTH ();                                        \
3754                                                                         \
3755   if (depth >= spelling_size)                                           \
3756     {                                                                   \
3757       spelling_size += 10;                                              \
3758       if (spelling_base == 0)                                           \
3759         spelling_base = xmalloc (spelling_size * sizeof (struct spelling)); \
3760       else                                                              \
3761         spelling_base = xrealloc (spelling_base,                \
3762                                   spelling_size * sizeof (struct spelling)); \
3763       RESTORE_SPELLING_DEPTH (depth);                                   \
3764     }                                                                   \
3765                                                                         \
3766   spelling->kind = (KIND);                                              \
3767   spelling->MEMBER = (VALUE);                                           \
3768   spelling++;                                                           \
3769 }
3770
3771 /* Push STRING on the stack.  Printed literally.  */
3772
3773 static void
3774 push_string (const char *string)
3775 {
3776   PUSH_SPELLING (SPELLING_STRING, string, u.s);
3777 }
3778
3779 /* Push a member name on the stack.  Printed as '.' STRING.  */
3780
3781 static void
3782 push_member_name (tree decl)
3783 {
3784   const char *const string
3785     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
3786   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
3787 }
3788
3789 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
3790
3791 static void
3792 push_array_bounds (int bounds)
3793 {
3794   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
3795 }
3796
3797 /* Compute the maximum size in bytes of the printed spelling.  */
3798
3799 static int
3800 spelling_length (void)
3801 {
3802   int size = 0;
3803   struct spelling *p;
3804
3805   for (p = spelling_base; p < spelling; p++)
3806     {
3807       if (p->kind == SPELLING_BOUNDS)
3808         size += 25;
3809       else
3810         size += strlen (p->u.s) + 1;
3811     }
3812
3813   return size;
3814 }
3815
3816 /* Print the spelling to BUFFER and return it.  */
3817
3818 static char *
3819 print_spelling (char *buffer)
3820 {
3821   char *d = buffer;
3822   struct spelling *p;
3823
3824   for (p = spelling_base; p < spelling; p++)
3825     if (p->kind == SPELLING_BOUNDS)
3826       {
3827         sprintf (d, "[%d]", p->u.i);
3828         d += strlen (d);
3829       }
3830     else
3831       {
3832         const char *s;
3833         if (p->kind == SPELLING_MEMBER)
3834           *d++ = '.';
3835         for (s = p->u.s; (*d = *s++); d++)
3836           ;
3837       }
3838   *d++ = '\0';
3839   return buffer;
3840 }
3841
3842 /* Issue an error message for a bad initializer component.
3843    MSGID identifies the message.
3844    The component name is taken from the spelling stack.  */
3845
3846 void
3847 error_init (const char *msgid)
3848 {
3849   char *ofwhat;
3850
3851   error ("%s", _(msgid));
3852   ofwhat = print_spelling (alloca (spelling_length () + 1));
3853   if (*ofwhat)
3854     error ("(near initialization for `%s')", ofwhat);
3855 }
3856
3857 /* Issue a pedantic warning for a bad initializer component.
3858    MSGID identifies the message.
3859    The component name is taken from the spelling stack.  */
3860
3861 void
3862 pedwarn_init (const char *msgid)
3863 {
3864   char *ofwhat;
3865
3866   pedwarn ("%s", _(msgid));
3867   ofwhat = print_spelling (alloca (spelling_length () + 1));
3868   if (*ofwhat)
3869     pedwarn ("(near initialization for `%s')", ofwhat);
3870 }
3871
3872 /* Issue a warning for a bad initializer component.
3873    MSGID identifies the message.
3874    The component name is taken from the spelling stack.  */
3875
3876 static void
3877 warning_init (const char *msgid)
3878 {
3879   char *ofwhat;
3880
3881   warning ("%s", _(msgid));
3882   ofwhat = print_spelling (alloca (spelling_length () + 1));
3883   if (*ofwhat)
3884     warning ("(near initialization for `%s')", ofwhat);
3885 }
3886 \f
3887 /* If TYPE is an array type and EXPR is a parenthesized string
3888    constant, warn if pedantic that EXPR is being used to initialize an
3889    object of type TYPE.  */
3890
3891 void
3892 maybe_warn_string_init (tree type, struct c_expr expr)
3893 {
3894   if (pedantic
3895       && TREE_CODE (type) == ARRAY_TYPE
3896       && TREE_CODE (expr.value) == STRING_CST
3897       && expr.original_code != STRING_CST)
3898     pedwarn_init ("array initialized from parenthesized string constant");
3899 }
3900
3901 /* Digest the parser output INIT as an initializer for type TYPE.
3902    Return a C expression of type TYPE to represent the initial value.
3903
3904    If INIT is a string constant, STRICT_STRING is true if it is
3905    unparenthesized or we should not warn here for it being parenthesized.
3906    For other types of INIT, STRICT_STRING is not used.
3907
3908    REQUIRE_CONSTANT requests an error if non-constant initializers or
3909    elements are seen.  */
3910
3911 static tree
3912 digest_init (tree type, tree init, bool strict_string, int require_constant)
3913 {
3914   enum tree_code code = TREE_CODE (type);
3915   tree inside_init = init;
3916
3917   if (type == error_mark_node
3918       || init == error_mark_node
3919       || TREE_TYPE (init) == error_mark_node)
3920     return error_mark_node;
3921
3922   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3923   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3924      whose value is 0 to count as a null pointer constant.  */
3925   if (TREE_CODE (init) == NON_LVALUE_EXPR)
3926     inside_init = TREE_OPERAND (init, 0);
3927
3928   inside_init = fold (inside_init);
3929
3930   /* Initialization of an array of chars from a string constant
3931      optionally enclosed in braces.  */
3932
3933   if (code == ARRAY_TYPE)
3934     {
3935       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
3936       if ((typ1 == char_type_node
3937            || typ1 == signed_char_type_node
3938            || typ1 == unsigned_char_type_node
3939            || typ1 == unsigned_wchar_type_node
3940            || typ1 == signed_wchar_type_node)
3941           && ((inside_init && TREE_CODE (inside_init) == STRING_CST)))
3942         {
3943           struct c_expr expr;
3944           expr.value = inside_init;
3945           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
3946           maybe_warn_string_init (type, expr);
3947
3948           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
3949                          TYPE_MAIN_VARIANT (type)))
3950             return inside_init;
3951
3952           if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3953                != char_type_node)
3954               && TYPE_PRECISION (typ1) == TYPE_PRECISION (char_type_node))
3955             {
3956               error_init ("char-array initialized from wide string");
3957               return error_mark_node;
3958             }
3959           if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3960                == char_type_node)
3961               && TYPE_PRECISION (typ1) != TYPE_PRECISION (char_type_node))
3962             {
3963               error_init ("int-array initialized from non-wide string");
3964               return error_mark_node;
3965             }
3966
3967           TREE_TYPE (inside_init) = type;
3968           if (TYPE_DOMAIN (type) != 0
3969               && TYPE_SIZE (type) != 0
3970               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
3971               /* Subtract 1 (or sizeof (wchar_t))
3972                  because it's ok to ignore the terminating null char
3973                  that is counted in the length of the constant.  */
3974               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
3975                                        TREE_STRING_LENGTH (inside_init)
3976                                        - ((TYPE_PRECISION (typ1)
3977                                            != TYPE_PRECISION (char_type_node))
3978                                           ? (TYPE_PRECISION (wchar_type_node)
3979                                              / BITS_PER_UNIT)
3980                                           : 1)))
3981             pedwarn_init ("initializer-string for array of chars is too long");
3982
3983           return inside_init;
3984         }
3985     }
3986
3987   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
3988      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
3989      below and handle as a constructor.  */
3990     if (code == VECTOR_TYPE
3991         && vector_types_convertible_p (TREE_TYPE (inside_init), type)
3992         && TREE_CONSTANT (inside_init))
3993       {
3994         if (TREE_CODE (inside_init) == VECTOR_CST
3995             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
3996                           TYPE_MAIN_VARIANT (type)))
3997           return inside_init;
3998         else
3999           return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4000       }
4001
4002   /* Any type can be initialized
4003      from an expression of the same type, optionally with braces.  */
4004
4005   if (inside_init && TREE_TYPE (inside_init) != 0
4006       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4007                      TYPE_MAIN_VARIANT (type))
4008           || (code == ARRAY_TYPE
4009               && comptypes (TREE_TYPE (inside_init), type))
4010           || (code == VECTOR_TYPE
4011               && comptypes (TREE_TYPE (inside_init), type))
4012           || (code == POINTER_TYPE
4013               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4014               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4015                             TREE_TYPE (type)))
4016           || (code == POINTER_TYPE
4017               && TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE
4018               && comptypes (TREE_TYPE (inside_init),
4019                             TREE_TYPE (type)))))
4020     {
4021       if (code == POINTER_TYPE)
4022         {
4023           inside_init = default_function_array_conversion (inside_init);
4024
4025           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4026             {
4027               error_init ("invalid use of non-lvalue array");
4028               return error_mark_node;
4029             }
4030          }
4031
4032       if (code == VECTOR_TYPE)
4033         /* Although the types are compatible, we may require a
4034            conversion.  */
4035         inside_init = convert (type, inside_init);
4036
4037       if (require_constant && !flag_isoc99
4038           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4039         {
4040           /* As an extension, allow initializing objects with static storage
4041              duration with compound literals (which are then treated just as
4042              the brace enclosed list they contain).  */
4043           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4044           inside_init = DECL_INITIAL (decl);
4045         }
4046
4047       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4048           && TREE_CODE (inside_init) != CONSTRUCTOR)
4049         {
4050           error_init ("array initialized from non-constant array expression");
4051           return error_mark_node;
4052         }
4053
4054       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4055         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4056
4057       /* Compound expressions can only occur here if -pedantic or
4058          -pedantic-errors is specified.  In the later case, we always want
4059          an error.  In the former case, we simply want a warning.  */
4060       if (require_constant && pedantic
4061           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4062         {
4063           inside_init
4064             = valid_compound_expr_initializer (inside_init,
4065                                                TREE_TYPE (inside_init));
4066           if (inside_init == error_mark_node)
4067             error_init ("initializer element is not constant");
4068           else
4069             pedwarn_init ("initializer element is not constant");
4070           if (flag_pedantic_errors)
4071             inside_init = error_mark_node;
4072         }
4073       else if (require_constant
4074                && (!TREE_CONSTANT (inside_init)
4075                    /* This test catches things like `7 / 0' which
4076                       result in an expression for which TREE_CONSTANT
4077                       is true, but which is not actually something
4078                       that is a legal constant.  We really should not
4079                       be using this function, because it is a part of
4080                       the back-end.  Instead, the expression should
4081                       already have been turned into ERROR_MARK_NODE.  */
4082                    || !initializer_constant_valid_p (inside_init,
4083                                                      TREE_TYPE (inside_init))))
4084         {
4085           error_init ("initializer element is not constant");
4086           inside_init = error_mark_node;
4087         }
4088
4089       return inside_init;
4090     }
4091
4092   /* Handle scalar types, including conversions.  */
4093
4094   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4095       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4096       || code == VECTOR_TYPE)
4097     {
4098       /* Note that convert_for_assignment calls default_conversion
4099          for arrays and functions.  We must not call it in the
4100          case where inside_init is a null pointer constant.  */
4101       inside_init
4102         = convert_for_assignment (type, init, _("initialization"),
4103                                   NULL_TREE, NULL_TREE, 0);
4104
4105       if (require_constant && ! TREE_CONSTANT (inside_init))
4106         {
4107           error_init ("initializer element is not constant");
4108           inside_init = error_mark_node;
4109         }
4110       else if (require_constant
4111                && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
4112         {
4113           error_init ("initializer element is not computable at load time");
4114           inside_init = error_mark_node;
4115         }
4116
4117       return inside_init;
4118     }
4119
4120   /* Come here only for records and arrays.  */
4121
4122   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4123     {
4124       error_init ("variable-sized object may not be initialized");
4125       return error_mark_node;
4126     }
4127
4128   error_init ("invalid initializer");
4129   return error_mark_node;
4130 }
4131 \f
4132 /* Handle initializers that use braces.  */
4133
4134 /* Type of object we are accumulating a constructor for.
4135    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4136 static tree constructor_type;
4137
4138 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4139    left to fill.  */
4140 static tree constructor_fields;
4141
4142 /* For an ARRAY_TYPE, this is the specified index
4143    at which to store the next element we get.  */
4144 static tree constructor_index;
4145
4146 /* For an ARRAY_TYPE, this is the maximum index.  */
4147 static tree constructor_max_index;
4148
4149 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4150 static tree constructor_unfilled_fields;
4151
4152 /* For an ARRAY_TYPE, this is the index of the first element
4153    not yet written out.  */
4154 static tree constructor_unfilled_index;
4155
4156 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4157    This is so we can generate gaps between fields, when appropriate.  */
4158 static tree constructor_bit_index;
4159
4160 /* If we are saving up the elements rather than allocating them,
4161    this is the list of elements so far (in reverse order,
4162    most recent first).  */
4163 static tree constructor_elements;
4164
4165 /* 1 if constructor should be incrementally stored into a constructor chain,
4166    0 if all the elements should be kept in AVL tree.  */
4167 static int constructor_incremental;
4168
4169 /* 1 if so far this constructor's elements are all compile-time constants.  */
4170 static int constructor_constant;
4171
4172 /* 1 if so far this constructor's elements are all valid address constants.  */
4173 static int constructor_simple;
4174
4175 /* 1 if this constructor is erroneous so far.  */
4176 static int constructor_erroneous;
4177
4178 /* Structure for managing pending initializer elements, organized as an
4179    AVL tree.  */
4180
4181 struct init_node
4182 {
4183   struct init_node *left, *right;
4184   struct init_node *parent;
4185   int balance;
4186   tree purpose;
4187   tree value;
4188 };
4189
4190 /* Tree of pending elements at this constructor level.
4191    These are elements encountered out of order
4192    which belong at places we haven't reached yet in actually
4193    writing the output.
4194    Will never hold tree nodes across GC runs.  */
4195 static struct init_node *constructor_pending_elts;
4196
4197 /* The SPELLING_DEPTH of this constructor.  */
4198 static int constructor_depth;
4199
4200 /* 0 if implicitly pushing constructor levels is allowed.  */
4201 int constructor_no_implicit = 0; /* 0 for C; 1 for some other languages.  */
4202
4203 /* DECL node for which an initializer is being read.
4204    0 means we are reading a constructor expression
4205    such as (struct foo) {...}.  */
4206 static tree constructor_decl;
4207
4208 /* start_init saves the ASMSPEC arg here for really_start_incremental_init.  */
4209 static const char *constructor_asmspec;
4210
4211 /* Nonzero if this is an initializer for a top-level decl.  */
4212 static int constructor_top_level;
4213
4214 /* Nonzero if there were any member designators in this initializer.  */
4215 static int constructor_designated;
4216
4217 /* Nesting depth of designator list.  */
4218 static int designator_depth;
4219
4220 /* Nonzero if there were diagnosed errors in this designator list.  */
4221 static int designator_errorneous;
4222
4223 \f
4224 /* This stack has a level for each implicit or explicit level of
4225    structuring in the initializer, including the outermost one.  It
4226    saves the values of most of the variables above.  */
4227
4228 struct constructor_range_stack;
4229
4230 struct constructor_stack
4231 {
4232   struct constructor_stack *next;
4233   tree type;
4234   tree fields;
4235   tree index;
4236   tree max_index;
4237   tree unfilled_index;
4238   tree unfilled_fields;
4239   tree bit_index;
4240   tree elements;
4241   struct init_node *pending_elts;
4242   int offset;
4243   int depth;
4244   /* If value nonzero, this value should replace the entire
4245      constructor at this level.  */
4246   struct c_expr replacement_value;
4247   struct constructor_range_stack *range_stack;
4248   char constant;
4249   char simple;
4250   char implicit;
4251   char erroneous;
4252   char outer;
4253   char incremental;
4254   char designated;
4255 };
4256
4257 struct constructor_stack *constructor_stack;
4258
4259 /* This stack represents designators from some range designator up to
4260    the last designator in the list.  */
4261
4262 struct constructor_range_stack
4263 {
4264   struct constructor_range_stack *next, *prev;
4265   struct constructor_stack *stack;
4266   tree range_start;
4267   tree index;
4268   tree range_end;
4269   tree fields;
4270 };
4271
4272 struct constructor_range_stack *constructor_range_stack;
4273
4274 /* This stack records separate initializers that are nested.
4275    Nested initializers can't happen in ANSI C, but GNU C allows them
4276    in cases like { ... (struct foo) { ... } ... }.  */
4277
4278 struct initializer_stack
4279 {
4280   struct initializer_stack *next;
4281   tree decl;
4282   const char *asmspec;
4283   struct constructor_stack *constructor_stack;
4284   struct constructor_range_stack *constructor_range_stack;
4285   tree elements;
4286   struct spelling *spelling;
4287   struct spelling *spelling_base;
4288   int spelling_size;
4289   char top_level;
4290   char require_constant_value;
4291   char require_constant_elements;
4292 };
4293
4294 struct initializer_stack *initializer_stack;
4295 \f
4296 /* Prepare to parse and output the initializer for variable DECL.  */
4297
4298 void
4299 start_init (tree decl, tree asmspec_tree, int top_level)
4300 {
4301   const char *locus;
4302   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4303   const char *asmspec = 0;
4304
4305   if (asmspec_tree)
4306     asmspec = TREE_STRING_POINTER (asmspec_tree);
4307
4308   p->decl = constructor_decl;
4309   p->asmspec = constructor_asmspec;
4310   p->require_constant_value = require_constant_value;
4311   p->require_constant_elements = require_constant_elements;
4312   p->constructor_stack = constructor_stack;
4313   p->constructor_range_stack = constructor_range_stack;
4314   p->elements = constructor_elements;
4315   p->spelling = spelling;
4316   p->spelling_base = spelling_base;
4317   p->spelling_size = spelling_size;
4318   p->top_level = constructor_top_level;
4319   p->next = initializer_stack;
4320   initializer_stack = p;
4321
4322   constructor_decl = decl;
4323   constructor_asmspec = asmspec;
4324   constructor_designated = 0;
4325   constructor_top_level = top_level;
4326
4327   if (decl != 0)
4328     {
4329       require_constant_value = TREE_STATIC (decl);
4330       require_constant_elements
4331         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4332            /* For a scalar, you can always use any value to initialize,
4333               even within braces.  */
4334            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4335                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4336                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4337                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4338       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4339     }
4340   else
4341     {
4342       require_constant_value = 0;
4343       require_constant_elements = 0;
4344       locus = "(anonymous)";
4345     }
4346
4347   constructor_stack = 0;
4348   constructor_range_stack = 0;
4349
4350   missing_braces_mentioned = 0;
4351
4352   spelling_base = 0;
4353   spelling_size = 0;
4354   RESTORE_SPELLING_DEPTH (0);
4355
4356   if (locus)
4357     push_string (locus);
4358 }
4359
4360 void
4361 finish_init (void)
4362 {
4363   struct initializer_stack *p = initializer_stack;
4364
4365   /* Free the whole constructor stack of this initializer.  */
4366   while (constructor_stack)
4367     {
4368       struct constructor_stack *q = constructor_stack;
4369       constructor_stack = q->next;
4370       free (q);
4371     }
4372
4373   if (constructor_range_stack)
4374     abort ();
4375
4376   /* Pop back to the data of the outer initializer (if any).  */
4377   free (spelling_base);
4378
4379   constructor_decl = p->decl;
4380   constructor_asmspec = p->asmspec;
4381   require_constant_value = p->require_constant_value;
4382   require_constant_elements = p->require_constant_elements;
4383   constructor_stack = p->constructor_stack;
4384   constructor_range_stack = p->constructor_range_stack;
4385   constructor_elements = p->elements;
4386   spelling = p->spelling;
4387   spelling_base = p->spelling_base;
4388   spelling_size = p->spelling_size;
4389   constructor_top_level = p->top_level;
4390   initializer_stack = p->next;
4391   free (p);
4392 }
4393 \f
4394 /* Call here when we see the initializer is surrounded by braces.
4395    This is instead of a call to push_init_level;
4396    it is matched by a call to pop_init_level.
4397
4398    TYPE is the type to initialize, for a constructor expression.
4399    For an initializer for a decl, TYPE is zero.  */
4400
4401 void
4402 really_start_incremental_init (tree type)
4403 {
4404   struct constructor_stack *p = xmalloc (sizeof (struct constructor_stack));
4405
4406   if (type == 0)
4407     type = TREE_TYPE (constructor_decl);
4408
4409   if (targetm.vector_opaque_p (type))
4410     error ("opaque vector types cannot be initialized");
4411
4412   p->type = constructor_type;
4413   p->fields = constructor_fields;
4414   p->index = constructor_index;
4415   p->max_index = constructor_max_index;
4416   p->unfilled_index = constructor_unfilled_index;
4417   p->unfilled_fields = constructor_unfilled_fields;
4418   p->bit_index = constructor_bit_index;
4419   p->elements = constructor_elements;
4420   p->constant = constructor_constant;
4421   p->simple = constructor_simple;
4422   p->erroneous = constructor_erroneous;
4423   p->pending_elts = constructor_pending_elts;
4424   p->depth = constructor_depth;
4425   p->replacement_value.value = 0;
4426   p->replacement_value.original_code = ERROR_MARK;
4427   p->implicit = 0;
4428   p->range_stack = 0;
4429   p->outer = 0;
4430   p->incremental = constructor_incremental;
4431   p->designated = constructor_designated;
4432   p->next = 0;
4433   constructor_stack = p;
4434
4435   constructor_constant = 1;
4436   constructor_simple = 1;
4437   constructor_depth = SPELLING_DEPTH ();
4438   constructor_elements = 0;
4439   constructor_pending_elts = 0;
4440   constructor_type = type;
4441   constructor_incremental = 1;
4442   constructor_designated = 0;
4443   designator_depth = 0;
4444   designator_errorneous = 0;
4445
4446   if (TREE_CODE (constructor_type) == RECORD_TYPE
4447       || TREE_CODE (constructor_type) == UNION_TYPE)
4448     {
4449       constructor_fields = TYPE_FIELDS (constructor_type);
4450       /* Skip any nameless bit fields at the beginning.  */
4451       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4452              && DECL_NAME (constructor_fields) == 0)
4453         constructor_fields = TREE_CHAIN (constructor_fields);
4454
4455       constructor_unfilled_fields = constructor_fields;
4456       constructor_bit_index = bitsize_zero_node;
4457     }
4458   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4459     {
4460       if (TYPE_DOMAIN (constructor_type))
4461         {
4462           constructor_max_index
4463             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4464
4465           /* Detect non-empty initializations of zero-length arrays.  */
4466           if (constructor_max_index == NULL_TREE
4467               && TYPE_SIZE (constructor_type))
4468             constructor_max_index = build_int_2 (-1, -1);
4469
4470           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4471              to initialize VLAs will cause a proper error; avoid tree
4472              checking errors as well by setting a safe value.  */
4473           if (constructor_max_index
4474               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4475             constructor_max_index = build_int_2 (-1, -1);
4476
4477           constructor_index
4478             = convert (bitsizetype,
4479                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4480         }
4481       else
4482         constructor_index = bitsize_zero_node;
4483
4484       constructor_unfilled_index = constructor_index;
4485     }
4486   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4487     {
4488       /* Vectors are like simple fixed-size arrays.  */
4489       constructor_max_index =
4490         build_int_2 (TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4491       constructor_index = convert (bitsizetype, bitsize_zero_node);
4492       constructor_unfilled_index = constructor_index;
4493     }
4494   else
4495     {
4496       /* Handle the case of int x = {5}; */
4497       constructor_fields = constructor_type;
4498       constructor_unfilled_fields = constructor_type;
4499     }
4500 }
4501 \f
4502 /* Push down into a subobject, for initialization.
4503    If this is for an explicit set of braces, IMPLICIT is 0.
4504    If it is because the next element belongs at a lower level,
4505    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4506
4507 void
4508 push_init_level (int implicit)
4509 {
4510   struct constructor_stack *p;
4511   tree value = NULL_TREE;
4512
4513   /* If we've exhausted any levels that didn't have braces,
4514      pop them now.  */
4515   while (constructor_stack->implicit)
4516     {
4517       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4518            || TREE_CODE (constructor_type) == UNION_TYPE)
4519           && constructor_fields == 0)
4520         process_init_element (pop_init_level (1));
4521       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4522                && constructor_max_index
4523                && tree_int_cst_lt (constructor_max_index, constructor_index))
4524         process_init_element (pop_init_level (1));
4525       else
4526         break;
4527     }
4528
4529   /* Unless this is an explicit brace, we need to preserve previous
4530      content if any.  */
4531   if (implicit)
4532     {
4533       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4534            || TREE_CODE (constructor_type) == UNION_TYPE)
4535           && constructor_fields)
4536         value = find_init_member (constructor_fields);
4537       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4538         value = find_init_member (constructor_index);
4539     }
4540
4541   p = xmalloc (sizeof (struct constructor_stack));
4542   p->type = constructor_type;
4543   p->fields = constructor_fields;
4544   p->index = constructor_index;
4545   p->max_index = constructor_max_index;
4546   p->unfilled_index = constructor_unfilled_index;
4547   p->unfilled_fields = constructor_unfilled_fields;
4548   p->bit_index = constructor_bit_index;
4549   p->elements = constructor_elements;
4550   p->constant = constructor_constant;
4551   p->simple = constructor_simple;
4552   p->erroneous = constructor_erroneous;
4553   p->pending_elts = constructor_pending_elts;
4554   p->depth = constructor_depth;
4555   p->replacement_value.value = 0;
4556   p->replacement_value.original_code = ERROR_MARK;
4557   p->implicit = implicit;
4558   p->outer = 0;
4559   p->incremental = constructor_incremental;
4560   p->designated = constructor_designated;
4561   p->next = constructor_stack;
4562   p->range_stack = 0;
4563   constructor_stack = p;
4564
4565   constructor_constant = 1;
4566   constructor_simple = 1;
4567   constructor_depth = SPELLING_DEPTH ();
4568   constructor_elements = 0;
4569   constructor_incremental = 1;
4570   constructor_designated = 0;
4571   constructor_pending_elts = 0;
4572   if (!implicit)
4573     {
4574       p->range_stack = constructor_range_stack;
4575       constructor_range_stack = 0;
4576       designator_depth = 0;
4577       designator_errorneous = 0;
4578     }
4579
4580   /* Don't die if an entire brace-pair level is superfluous
4581      in the containing level.  */
4582   if (constructor_type == 0)
4583     ;
4584   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4585            || TREE_CODE (constructor_type) == UNION_TYPE)
4586     {
4587       /* Don't die if there are extra init elts at the end.  */
4588       if (constructor_fields == 0)
4589         constructor_type = 0;
4590       else
4591         {
4592           constructor_type = TREE_TYPE (constructor_fields);
4593           push_member_name (constructor_fields);
4594           constructor_depth++;
4595         }
4596     }
4597   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4598     {
4599       constructor_type = TREE_TYPE (constructor_type);
4600       push_array_bounds (tree_low_cst (constructor_index, 0));
4601       constructor_depth++;
4602     }
4603
4604   if (constructor_type == 0)
4605     {
4606       error_init ("extra brace group at end of initializer");
4607       constructor_fields = 0;
4608       constructor_unfilled_fields = 0;
4609       return;
4610     }
4611
4612   if (value && TREE_CODE (value) == CONSTRUCTOR)
4613     {
4614       constructor_constant = TREE_CONSTANT (value);
4615       constructor_simple = TREE_STATIC (value);
4616       constructor_elements = CONSTRUCTOR_ELTS (value);
4617       if (constructor_elements
4618           && (TREE_CODE (constructor_type) == RECORD_TYPE
4619               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4620         set_nonincremental_init ();
4621     }
4622
4623   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4624     {
4625       missing_braces_mentioned = 1;
4626       warning_init ("missing braces around initializer");
4627     }
4628
4629   if (TREE_CODE (constructor_type) == RECORD_TYPE
4630            || TREE_CODE (constructor_type) == UNION_TYPE)
4631     {
4632       constructor_fields = TYPE_FIELDS (constructor_type);
4633       /* Skip any nameless bit fields at the beginning.  */
4634       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4635              && DECL_NAME (constructor_fields) == 0)
4636         constructor_fields = TREE_CHAIN (constructor_fields);
4637
4638       constructor_unfilled_fields = constructor_fields;
4639       constructor_bit_index = bitsize_zero_node;
4640     }
4641   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4642     {
4643       /* Vectors are like simple fixed-size arrays.  */
4644       constructor_max_index =
4645         build_int_2 (TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4646       constructor_index = convert (bitsizetype, integer_zero_node);
4647       constructor_unfilled_index = constructor_index;
4648     }
4649   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4650     {
4651       if (TYPE_DOMAIN (constructor_type))
4652         {
4653           constructor_max_index
4654             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4655
4656           /* Detect non-empty initializations of zero-length arrays.  */
4657           if (constructor_max_index == NULL_TREE
4658               && TYPE_SIZE (constructor_type))
4659             constructor_max_index = build_int_2 (-1, -1);
4660
4661           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4662              to initialize VLAs will cause a proper error; avoid tree
4663              checking errors as well by setting a safe value.  */
4664           if (constructor_max_index
4665               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4666             constructor_max_index = build_int_2 (-1, -1);
4667
4668           constructor_index
4669             = convert (bitsizetype,
4670                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4671         }
4672       else
4673         constructor_index = bitsize_zero_node;
4674
4675       constructor_unfilled_index = constructor_index;
4676       if (value && TREE_CODE (value) == STRING_CST)
4677         {
4678           /* We need to split the char/wchar array into individual
4679              characters, so that we don't have to special case it
4680              everywhere.  */
4681           set_nonincremental_init_from_string (value);
4682         }
4683     }
4684   else
4685     {
4686       warning_init ("braces around scalar initializer");
4687       constructor_fields = constructor_type;
4688       constructor_unfilled_fields = constructor_type;
4689     }
4690 }
4691
4692 /* At the end of an implicit or explicit brace level,
4693    finish up that level of constructor.  If a single expression
4694    with redundant braces initialized that level, return the
4695    c_expr structure for that expression.  Otherwise, the original_code
4696    element is set to ERROR_MARK.
4697    If we were outputting the elements as they are read, return 0 as the value
4698    from inner levels (process_init_element ignores that),
4699    but return error_mark_node as the value from the outermost level
4700    (that's what we want to put in DECL_INITIAL).
4701    Otherwise, return a CONSTRUCTOR expression as the value.  */
4702
4703 struct c_expr
4704 pop_init_level (int implicit)
4705 {
4706   struct constructor_stack *p;
4707   struct c_expr ret;
4708   ret.value = 0;
4709   ret.original_code = ERROR_MARK;
4710
4711   if (implicit == 0)
4712     {
4713       /* When we come to an explicit close brace,
4714          pop any inner levels that didn't have explicit braces.  */
4715       while (constructor_stack->implicit)
4716         process_init_element (pop_init_level (1));
4717
4718       if (constructor_range_stack)
4719         abort ();
4720     }
4721
4722   /* Now output all pending elements.  */
4723   constructor_incremental = 1;
4724   output_pending_init_elements (1);
4725
4726   p = constructor_stack;
4727
4728   /* Error for initializing a flexible array member, or a zero-length
4729      array member in an inappropriate context.  */
4730   if (constructor_type && constructor_fields
4731       && TREE_CODE (constructor_type) == ARRAY_TYPE
4732       && TYPE_DOMAIN (constructor_type)
4733       && ! TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
4734     {
4735       /* Silently discard empty initializations.  The parser will
4736          already have pedwarned for empty brackets.  */
4737       if (integer_zerop (constructor_unfilled_index))
4738         constructor_type = NULL_TREE;
4739       else if (! TYPE_SIZE (constructor_type))
4740         {
4741           if (constructor_depth > 2)
4742             error_init ("initialization of flexible array member in a nested context");
4743           else if (pedantic)
4744             pedwarn_init ("initialization of a flexible array member");
4745
4746           /* We have already issued an error message for the existence
4747              of a flexible array member not at the end of the structure.
4748              Discard the initializer so that we do not abort later.  */
4749           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
4750             constructor_type = NULL_TREE;
4751         }
4752       else
4753         /* Zero-length arrays are no longer special, so we should no longer
4754            get here.  */
4755         abort ();
4756     }
4757
4758   /* Warn when some struct elements are implicitly initialized to zero.  */
4759   if (extra_warnings
4760       && constructor_type
4761       && TREE_CODE (constructor_type) == RECORD_TYPE
4762       && constructor_unfilled_fields)
4763     {
4764         /* Do not warn for flexible array members or zero-length arrays.  */
4765         while (constructor_unfilled_fields
4766                && (! DECL_SIZE (constructor_unfilled_fields)
4767                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
4768           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
4769
4770         /* Do not warn if this level of the initializer uses member
4771            designators; it is likely to be deliberate.  */
4772         if (constructor_unfilled_fields && !constructor_designated)
4773           {
4774             push_member_name (constructor_unfilled_fields);
4775             warning_init ("missing initializer");
4776             RESTORE_SPELLING_DEPTH (constructor_depth);
4777           }
4778     }
4779
4780   /* Pad out the end of the structure.  */
4781   if (p->replacement_value.value)
4782     /* If this closes a superfluous brace pair,
4783        just pass out the element between them.  */
4784     ret = p->replacement_value;
4785   else if (constructor_type == 0)
4786     ;
4787   else if (TREE_CODE (constructor_type) != RECORD_TYPE
4788            && TREE_CODE (constructor_type) != UNION_TYPE
4789            && TREE_CODE (constructor_type) != ARRAY_TYPE
4790            && TREE_CODE (constructor_type) != VECTOR_TYPE)
4791     {
4792       /* A nonincremental scalar initializer--just return
4793          the element, after verifying there is just one.  */
4794       if (constructor_elements == 0)
4795         {
4796           if (!constructor_erroneous)
4797             error_init ("empty scalar initializer");
4798           ret.value = error_mark_node;
4799         }
4800       else if (TREE_CHAIN (constructor_elements) != 0)
4801         {
4802           error_init ("extra elements in scalar initializer");
4803           ret.value = TREE_VALUE (constructor_elements);
4804         }
4805       else
4806         ret.value = TREE_VALUE (constructor_elements);
4807     }
4808   else
4809     {
4810       if (constructor_erroneous)
4811         ret.value = error_mark_node;
4812       else
4813         {
4814           ret.value = build_constructor (constructor_type,
4815                                          nreverse (constructor_elements));
4816           if (constructor_constant)
4817             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
4818           if (constructor_constant && constructor_simple)
4819             TREE_STATIC (ret.value) = 1;
4820         }
4821     }
4822
4823   constructor_type = p->type;
4824   constructor_fields = p->fields;
4825   constructor_index = p->index;
4826   constructor_max_index = p->max_index;
4827   constructor_unfilled_index = p->unfilled_index;
4828   constructor_unfilled_fields = p->unfilled_fields;
4829   constructor_bit_index = p->bit_index;
4830   constructor_elements = p->elements;
4831   constructor_constant = p->constant;
4832   constructor_simple = p->simple;
4833   constructor_erroneous = p->erroneous;
4834   constructor_incremental = p->incremental;
4835   constructor_designated = p->designated;
4836   constructor_pending_elts = p->pending_elts;
4837   constructor_depth = p->depth;
4838   if (!p->implicit)
4839     constructor_range_stack = p->range_stack;
4840   RESTORE_SPELLING_DEPTH (constructor_depth);
4841
4842   constructor_stack = p->next;
4843   free (p);
4844
4845   if (ret.value == 0)
4846     {
4847       if (constructor_stack == 0)
4848         {
4849           ret.value = error_mark_node;
4850           return ret;
4851         }
4852       return ret;
4853     }
4854   return ret;
4855 }
4856
4857 /* Common handling for both array range and field name designators.
4858    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
4859
4860 static int
4861 set_designator (int array)
4862 {
4863   tree subtype;
4864   enum tree_code subcode;
4865
4866   /* Don't die if an entire brace-pair level is superfluous
4867      in the containing level.  */
4868   if (constructor_type == 0)
4869     return 1;
4870
4871   /* If there were errors in this designator list already, bail out silently.  */
4872   if (designator_errorneous)
4873     return 1;
4874
4875   if (!designator_depth)
4876     {
4877       if (constructor_range_stack)
4878         abort ();
4879
4880       /* Designator list starts at the level of closest explicit
4881          braces.  */
4882       while (constructor_stack->implicit)
4883         process_init_element (pop_init_level (1));
4884       constructor_designated = 1;
4885       return 0;
4886     }
4887
4888   if (constructor_no_implicit)
4889     {
4890       error_init ("initialization designators may not nest");
4891       return 1;
4892     }
4893
4894   if (TREE_CODE (constructor_type) == RECORD_TYPE
4895       || TREE_CODE (constructor_type) == UNION_TYPE)
4896     {
4897       subtype = TREE_TYPE (constructor_fields);
4898       if (subtype != error_mark_node)
4899         subtype = TYPE_MAIN_VARIANT (subtype);
4900     }
4901   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4902     {
4903       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
4904     }
4905   else
4906     abort ();
4907
4908   subcode = TREE_CODE (subtype);
4909   if (array && subcode != ARRAY_TYPE)
4910     {
4911       error_init ("array index in non-array initializer");
4912       return 1;
4913     }
4914   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
4915     {
4916       error_init ("field name not in record or union initializer");
4917       return 1;
4918     }
4919
4920   constructor_designated = 1;
4921   push_init_level (2);
4922   return 0;
4923 }
4924
4925 /* If there are range designators in designator list, push a new designator
4926    to constructor_range_stack.  RANGE_END is end of such stack range or
4927    NULL_TREE if there is no range designator at this level.  */
4928
4929 static void
4930 push_range_stack (tree range_end)
4931 {
4932   struct constructor_range_stack *p;
4933
4934   p = ggc_alloc (sizeof (struct constructor_range_stack));
4935   p->prev = constructor_range_stack;
4936   p->next = 0;
4937   p->fields = constructor_fields;
4938   p->range_start = constructor_index;
4939   p->index = constructor_index;
4940   p->stack = constructor_stack;
4941   p->range_end = range_end;
4942   if (constructor_range_stack)
4943     constructor_range_stack->next = p;
4944   constructor_range_stack = p;
4945 }
4946
4947 /* Within an array initializer, specify the next index to be initialized.
4948    FIRST is that index.  If LAST is nonzero, then initialize a range
4949    of indices, running from FIRST through LAST.  */
4950
4951 void
4952 set_init_index (tree first, tree last)
4953 {
4954   if (set_designator (1))
4955     return;
4956
4957   designator_errorneous = 1;
4958
4959   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
4960       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
4961     {
4962       error_init ("array index in initializer not of integer type");
4963       return;
4964     }
4965
4966   while ((TREE_CODE (first) == NOP_EXPR
4967           || TREE_CODE (first) == CONVERT_EXPR
4968           || TREE_CODE (first) == NON_LVALUE_EXPR)
4969          && (TYPE_MODE (TREE_TYPE (first))
4970              == TYPE_MODE (TREE_TYPE (TREE_OPERAND (first, 0)))))
4971     first = TREE_OPERAND (first, 0);
4972
4973   if (last)
4974     while ((TREE_CODE (last) == NOP_EXPR
4975             || TREE_CODE (last) == CONVERT_EXPR
4976             || TREE_CODE (last) == NON_LVALUE_EXPR)
4977            && (TYPE_MODE (TREE_TYPE (last))
4978                == TYPE_MODE (TREE_TYPE (TREE_OPERAND (last, 0)))))
4979       last = TREE_OPERAND (last, 0);
4980
4981   if (TREE_CODE (first) != INTEGER_CST)
4982     error_init ("nonconstant array index in initializer");
4983   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
4984     error_init ("nonconstant array index in initializer");
4985   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
4986     error_init ("array index in non-array initializer");
4987   else if (tree_int_cst_sgn (first) == -1)
4988     error_init ("array index in initializer exceeds array bounds");
4989   else if (constructor_max_index
4990            && tree_int_cst_lt (constructor_max_index, first))
4991     error_init ("array index in initializer exceeds array bounds");
4992   else
4993     {
4994       constructor_index = convert (bitsizetype, first);
4995
4996       if (last)
4997         {
4998           if (tree_int_cst_equal (first, last))
4999             last = 0;
5000           else if (tree_int_cst_lt (last, first))
5001             {
5002               error_init ("empty index range in initializer");
5003               last = 0;
5004             }
5005           else
5006             {
5007               last = convert (bitsizetype, last);
5008               if (constructor_max_index != 0
5009                   && tree_int_cst_lt (constructor_max_index, last))
5010                 {
5011                   error_init ("array index range in initializer exceeds array bounds");
5012                   last = 0;
5013                 }
5014             }
5015         }
5016
5017       designator_depth++;
5018       designator_errorneous = 0;
5019       if (constructor_range_stack || last)
5020         push_range_stack (last);
5021     }
5022 }
5023
5024 /* Within a struct initializer, specify the next field to be initialized.  */
5025
5026 void
5027 set_init_label (tree fieldname)
5028 {
5029   tree tail;
5030
5031   if (set_designator (0))
5032     return;
5033
5034   designator_errorneous = 1;
5035
5036   if (TREE_CODE (constructor_type) != RECORD_TYPE
5037       && TREE_CODE (constructor_type) != UNION_TYPE)
5038     {
5039       error_init ("field name not in record or union initializer");
5040       return;
5041     }
5042
5043   for (tail = TYPE_FIELDS (constructor_type); tail;
5044        tail = TREE_CHAIN (tail))
5045     {
5046       if (DECL_NAME (tail) == fieldname)
5047         break;
5048     }
5049
5050   if (tail == 0)
5051     error ("unknown field `%s' specified in initializer",
5052            IDENTIFIER_POINTER (fieldname));
5053   else
5054     {
5055       constructor_fields = tail;
5056       designator_depth++;
5057       designator_errorneous = 0;
5058       if (constructor_range_stack)
5059         push_range_stack (NULL_TREE);
5060     }
5061 }
5062 \f
5063 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5064    identifies the initializer, either array index or field in a structure.
5065    VALUE is the value of that index or field.  */
5066
5067 static void
5068 add_pending_init (tree purpose, tree value)
5069 {
5070   struct init_node *p, **q, *r;
5071
5072   q = &constructor_pending_elts;
5073   p = 0;
5074
5075   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5076     {
5077       while (*q != 0)
5078         {
5079           p = *q;
5080           if (tree_int_cst_lt (purpose, p->purpose))
5081             q = &p->left;
5082           else if (tree_int_cst_lt (p->purpose, purpose))
5083             q = &p->right;
5084           else
5085             {
5086               if (TREE_SIDE_EFFECTS (p->value))
5087                 warning_init ("initialized field with side-effects overwritten");
5088               p->value = value;
5089               return;
5090             }
5091         }
5092     }
5093   else
5094     {
5095       tree bitpos;
5096
5097       bitpos = bit_position (purpose);
5098       while (*q != NULL)
5099         {
5100           p = *q;
5101           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5102             q = &p->left;
5103           else if (p->purpose != purpose)
5104             q = &p->right;
5105           else
5106             {
5107               if (TREE_SIDE_EFFECTS (p->value))
5108                 warning_init ("initialized field with side-effects overwritten");
5109               p->value = value;
5110               return;
5111             }
5112         }
5113     }
5114
5115   r = ggc_alloc (sizeof (struct init_node));
5116   r->purpose = purpose;
5117   r->value = value;
5118
5119   *q = r;
5120   r->parent = p;
5121   r->left = 0;
5122   r->right = 0;
5123   r->balance = 0;
5124
5125   while (p)
5126     {
5127       struct init_node *s;
5128
5129       if (r == p->left)
5130         {
5131           if (p->balance == 0)
5132             p->balance = -1;
5133           else if (p->balance < 0)
5134             {
5135               if (r->balance < 0)
5136                 {
5137                   /* L rotation.  */
5138                   p->left = r->right;
5139                   if (p->left)
5140                     p->left->parent = p;
5141                   r->right = p;
5142
5143                   p->balance = 0;
5144                   r->balance = 0;
5145
5146                   s = p->parent;
5147                   p->parent = r;
5148                   r->parent = s;
5149                   if (s)
5150                     {
5151                       if (s->left == p)
5152                         s->left = r;
5153                       else
5154                         s->right = r;
5155                     }
5156                   else
5157                     constructor_pending_elts = r;
5158                 }
5159               else
5160                 {
5161                   /* LR rotation.  */
5162                   struct init_node *t = r->right;
5163
5164                   r->right = t->left;
5165                   if (r->right)
5166                     r->right->parent = r;
5167                   t->left = r;
5168
5169                   p->left = t->right;
5170                   if (p->left)
5171                     p->left->parent = p;
5172                   t->right = p;
5173
5174                   p->balance = t->balance < 0;
5175                   r->balance = -(t->balance > 0);
5176                   t->balance = 0;
5177
5178                   s = p->parent;
5179                   p->parent = t;
5180                   r->parent = t;
5181                   t->parent = s;
5182                   if (s)
5183                     {
5184                       if (s->left == p)
5185                         s->left = t;
5186                       else
5187                         s->right = t;
5188                     }
5189                   else
5190                     constructor_pending_elts = t;
5191                 }
5192               break;
5193             }
5194           else
5195             {
5196               /* p->balance == +1; growth of left side balances the node.  */
5197               p->balance = 0;
5198               break;
5199             }
5200         }
5201       else /* r == p->right */
5202         {
5203           if (p->balance == 0)
5204             /* Growth propagation from right side.  */
5205             p->balance++;
5206           else if (p->balance > 0)
5207             {
5208               if (r->balance > 0)
5209                 {
5210                   /* R rotation.  */
5211                   p->right = r->left;
5212                   if (p->right)
5213                     p->right->parent = p;
5214                   r->left = p;
5215
5216                   p->balance = 0;
5217                   r->balance = 0;
5218
5219                   s = p->parent;
5220                   p->parent = r;
5221                   r->parent = s;
5222                   if (s)
5223                     {
5224                       if (s->left == p)
5225                         s->left = r;
5226                       else
5227                         s->right = r;
5228                     }
5229                   else
5230                     constructor_pending_elts = r;
5231                 }
5232               else /* r->balance == -1 */
5233                 {
5234                   /* RL rotation */
5235                   struct init_node *t = r->left;
5236
5237                   r->left = t->right;
5238                   if (r->left)
5239                     r->left->parent = r;
5240                   t->right = r;
5241
5242                   p->right = t->left;
5243                   if (p->right)
5244                     p->right->parent = p;
5245                   t->left = p;
5246
5247                   r->balance = (t->balance < 0);
5248                   p->balance = -(t->balance > 0);
5249                   t->balance = 0;
5250
5251                   s = p->parent;
5252                   p->parent = t;
5253                   r->parent = t;
5254                   t->parent = s;
5255                   if (s)
5256                     {
5257                       if (s->left == p)
5258                         s->left = t;
5259                       else
5260                         s->right = t;
5261                     }
5262                   else
5263                     constructor_pending_elts = t;
5264                 }
5265               break;
5266             }
5267           else
5268             {
5269               /* p->balance == -1; growth of right side balances the node.  */
5270               p->balance = 0;
5271               break;
5272             }
5273         }
5274
5275       r = p;
5276       p = p->parent;
5277     }
5278 }
5279
5280 /* Build AVL tree from a sorted chain.  */
5281
5282 static void
5283 set_nonincremental_init (void)
5284 {
5285   tree chain;
5286
5287   if (TREE_CODE (constructor_type) != RECORD_TYPE
5288       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5289     return;
5290
5291   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5292     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5293   constructor_elements = 0;
5294   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5295     {
5296       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5297       /* Skip any nameless bit fields at the beginning.  */
5298       while (constructor_unfilled_fields != 0
5299              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5300              && DECL_NAME (constructor_unfilled_fields) == 0)
5301         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5302
5303     }
5304   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5305     {
5306       if (TYPE_DOMAIN (constructor_type))
5307         constructor_unfilled_index
5308             = convert (bitsizetype,
5309                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5310       else
5311         constructor_unfilled_index = bitsize_zero_node;
5312     }
5313   constructor_incremental = 0;
5314 }
5315
5316 /* Build AVL tree from a string constant.  */
5317
5318 static void
5319 set_nonincremental_init_from_string (tree str)
5320 {
5321   tree value, purpose, type;
5322   HOST_WIDE_INT val[2];
5323   const char *p, *end;
5324   int byte, wchar_bytes, charwidth, bitpos;
5325
5326   if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5327     abort ();
5328
5329   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5330       == TYPE_PRECISION (char_type_node))
5331     wchar_bytes = 1;
5332   else if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5333            == TYPE_PRECISION (wchar_type_node))
5334     wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5335   else
5336     abort ();
5337
5338   charwidth = TYPE_PRECISION (char_type_node);
5339   type = TREE_TYPE (constructor_type);
5340   p = TREE_STRING_POINTER (str);
5341   end = p + TREE_STRING_LENGTH (str);
5342
5343   for (purpose = bitsize_zero_node;
5344        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5345        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5346     {
5347       if (wchar_bytes == 1)
5348         {
5349           val[1] = (unsigned char) *p++;
5350           val[0] = 0;
5351         }
5352       else
5353         {
5354           val[0] = 0;
5355           val[1] = 0;
5356           for (byte = 0; byte < wchar_bytes; byte++)
5357             {
5358               if (BYTES_BIG_ENDIAN)
5359                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5360               else
5361                 bitpos = byte * charwidth;
5362               val[bitpos < HOST_BITS_PER_WIDE_INT]
5363                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5364                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5365             }
5366         }
5367
5368       if (!TYPE_UNSIGNED (type))
5369         {
5370           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5371           if (bitpos < HOST_BITS_PER_WIDE_INT)
5372             {
5373               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5374                 {
5375                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5376                   val[0] = -1;
5377                 }
5378             }
5379           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5380             {
5381               if (val[1] < 0)
5382                 val[0] = -1;
5383             }
5384           else if (val[0] & (((HOST_WIDE_INT) 1)
5385                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5386             val[0] |= ((HOST_WIDE_INT) -1)
5387                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5388         }
5389
5390       value = build_int_2 (val[1], val[0]);
5391       TREE_TYPE (value) = type;
5392       add_pending_init (purpose, value);
5393     }
5394
5395   constructor_incremental = 0;
5396 }
5397
5398 /* Return value of FIELD in pending initializer or zero if the field was
5399    not initialized yet.  */
5400
5401 static tree
5402 find_init_member (tree field)
5403 {
5404   struct init_node *p;
5405
5406   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5407     {
5408       if (constructor_incremental
5409           && tree_int_cst_lt (field, constructor_unfilled_index))
5410         set_nonincremental_init ();
5411
5412       p = constructor_pending_elts;
5413       while (p)
5414         {
5415           if (tree_int_cst_lt (field, p->purpose))
5416             p = p->left;
5417           else if (tree_int_cst_lt (p->purpose, field))
5418             p = p->right;
5419           else
5420             return p->value;
5421         }
5422     }
5423   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5424     {
5425       tree bitpos = bit_position (field);
5426
5427       if (constructor_incremental
5428           && (!constructor_unfilled_fields
5429               || tree_int_cst_lt (bitpos,
5430                                   bit_position (constructor_unfilled_fields))))
5431         set_nonincremental_init ();
5432
5433       p = constructor_pending_elts;
5434       while (p)
5435         {
5436           if (field == p->purpose)
5437             return p->value;
5438           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5439             p = p->left;
5440           else
5441             p = p->right;
5442         }
5443     }
5444   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5445     {
5446       if (constructor_elements
5447           && TREE_PURPOSE (constructor_elements) == field)
5448         return TREE_VALUE (constructor_elements);
5449     }
5450   return 0;
5451 }
5452
5453 /* "Output" the next constructor element.
5454    At top level, really output it to assembler code now.
5455    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5456    TYPE is the data type that the containing data type wants here.
5457    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5458    If VALUE is a string constant, STRICT_STRING is true if it is
5459    unparenthesized or we should not warn here for it being parenthesized.
5460    For other types of VALUE, STRICT_STRING is not used.
5461
5462    PENDING if non-nil means output pending elements that belong
5463    right after this element.  (PENDING is normally 1;
5464    it is 0 while outputting pending elements, to avoid recursion.)  */
5465
5466 static void
5467 output_init_element (tree value, bool strict_string, tree type, tree field,
5468                      int pending)
5469 {
5470   if (type == error_mark_node)
5471     {
5472       constructor_erroneous = 1;
5473       return;
5474     }
5475   if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
5476       || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5477           && !(TREE_CODE (value) == STRING_CST
5478                && TREE_CODE (type) == ARRAY_TYPE
5479                && TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE)
5480           && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5481                          TYPE_MAIN_VARIANT (type))))
5482     value = default_conversion (value);
5483
5484   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5485       && require_constant_value && !flag_isoc99 && pending)
5486     {
5487       /* As an extension, allow initializing objects with static storage
5488          duration with compound literals (which are then treated just as
5489          the brace enclosed list they contain).  */
5490       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5491       value = DECL_INITIAL (decl);
5492     }
5493
5494   if (value == error_mark_node)
5495     constructor_erroneous = 1;
5496   else if (!TREE_CONSTANT (value))
5497     constructor_constant = 0;
5498   else if (initializer_constant_valid_p (value, TREE_TYPE (value)) == 0
5499            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5500                 || TREE_CODE (constructor_type) == UNION_TYPE)
5501                && DECL_C_BIT_FIELD (field)
5502                && TREE_CODE (value) != INTEGER_CST))
5503     constructor_simple = 0;
5504
5505   if (require_constant_value && ! TREE_CONSTANT (value))
5506     {
5507       error_init ("initializer element is not constant");
5508       value = error_mark_node;
5509     }
5510   else if (require_constant_elements
5511            && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
5512     pedwarn ("initializer element is not computable at load time");
5513
5514   /* If this field is empty (and not at the end of structure),
5515      don't do anything other than checking the initializer.  */
5516   if (field
5517       && (TREE_TYPE (field) == error_mark_node
5518           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5519               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5520               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5521                   || TREE_CHAIN (field)))))
5522     return;
5523
5524   value = digest_init (type, value, strict_string, require_constant_value);
5525   if (value == error_mark_node)
5526     {
5527       constructor_erroneous = 1;
5528       return;
5529     }
5530
5531   /* If this element doesn't come next in sequence,
5532      put it on constructor_pending_elts.  */
5533   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5534       && (!constructor_incremental
5535           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5536     {
5537       if (constructor_incremental
5538           && tree_int_cst_lt (field, constructor_unfilled_index))
5539         set_nonincremental_init ();
5540
5541       add_pending_init (field, value);
5542       return;
5543     }
5544   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5545            && (!constructor_incremental
5546                || field != constructor_unfilled_fields))
5547     {
5548       /* We do this for records but not for unions.  In a union,
5549          no matter which field is specified, it can be initialized
5550          right away since it starts at the beginning of the union.  */
5551       if (constructor_incremental)
5552         {
5553           if (!constructor_unfilled_fields)
5554             set_nonincremental_init ();
5555           else
5556             {
5557               tree bitpos, unfillpos;
5558
5559               bitpos = bit_position (field);
5560               unfillpos = bit_position (constructor_unfilled_fields);
5561
5562               if (tree_int_cst_lt (bitpos, unfillpos))
5563                 set_nonincremental_init ();
5564             }
5565         }
5566
5567       add_pending_init (field, value);
5568       return;
5569     }
5570   else if (TREE_CODE (constructor_type) == UNION_TYPE
5571            && constructor_elements)
5572     {
5573       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5574         warning_init ("initialized field with side-effects overwritten");
5575
5576       /* We can have just one union field set.  */
5577       constructor_elements = 0;
5578     }
5579
5580   /* Otherwise, output this element either to
5581      constructor_elements or to the assembler file.  */
5582
5583   if (field && TREE_CODE (field) == INTEGER_CST)
5584     field = copy_node (field);
5585   constructor_elements
5586     = tree_cons (field, value, constructor_elements);
5587
5588   /* Advance the variable that indicates sequential elements output.  */
5589   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5590     constructor_unfilled_index
5591       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5592                     bitsize_one_node);
5593   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5594     {
5595       constructor_unfilled_fields
5596         = TREE_CHAIN (constructor_unfilled_fields);
5597
5598       /* Skip any nameless bit fields.  */
5599       while (constructor_unfilled_fields != 0
5600              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5601              && DECL_NAME (constructor_unfilled_fields) == 0)
5602         constructor_unfilled_fields =
5603           TREE_CHAIN (constructor_unfilled_fields);
5604     }
5605   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5606     constructor_unfilled_fields = 0;
5607
5608   /* Now output any pending elements which have become next.  */
5609   if (pending)
5610     output_pending_init_elements (0);
5611 }
5612
5613 /* Output any pending elements which have become next.
5614    As we output elements, constructor_unfilled_{fields,index}
5615    advances, which may cause other elements to become next;
5616    if so, they too are output.
5617
5618    If ALL is 0, we return when there are
5619    no more pending elements to output now.
5620
5621    If ALL is 1, we output space as necessary so that
5622    we can output all the pending elements.  */
5623
5624 static void
5625 output_pending_init_elements (int all)
5626 {
5627   struct init_node *elt = constructor_pending_elts;
5628   tree next;
5629
5630  retry:
5631
5632   /* Look through the whole pending tree.
5633      If we find an element that should be output now,
5634      output it.  Otherwise, set NEXT to the element
5635      that comes first among those still pending.  */
5636
5637   next = 0;
5638   while (elt)
5639     {
5640       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5641         {
5642           if (tree_int_cst_equal (elt->purpose,
5643                                   constructor_unfilled_index))
5644             output_init_element (elt->value, true,
5645                                  TREE_TYPE (constructor_type),
5646                                  constructor_unfilled_index, 0);
5647           else if (tree_int_cst_lt (constructor_unfilled_index,
5648                                     elt->purpose))
5649             {
5650               /* Advance to the next smaller node.  */
5651               if (elt->left)
5652                 elt = elt->left;
5653               else
5654                 {
5655                   /* We have reached the smallest node bigger than the
5656                      current unfilled index.  Fill the space first.  */
5657                   next = elt->purpose;
5658                   break;
5659                 }
5660             }
5661           else
5662             {
5663               /* Advance to the next bigger node.  */
5664               if (elt->right)
5665                 elt = elt->right;
5666               else
5667                 {
5668                   /* We have reached the biggest node in a subtree.  Find
5669                      the parent of it, which is the next bigger node.  */
5670                   while (elt->parent && elt->parent->right == elt)
5671                     elt = elt->parent;
5672                   elt = elt->parent;
5673                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5674                                               elt->purpose))
5675                     {
5676                       next = elt->purpose;
5677                       break;
5678                     }
5679                 }
5680             }
5681         }
5682       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5683                || TREE_CODE (constructor_type) == UNION_TYPE)
5684         {
5685           tree ctor_unfilled_bitpos, elt_bitpos;
5686
5687           /* If the current record is complete we are done.  */
5688           if (constructor_unfilled_fields == 0)
5689             break;
5690
5691           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5692           elt_bitpos = bit_position (elt->purpose);
5693           /* We can't compare fields here because there might be empty
5694              fields in between.  */
5695           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
5696             {
5697               constructor_unfilled_fields = elt->purpose;
5698               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
5699                                    elt->purpose, 0);
5700             }
5701           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
5702             {
5703               /* Advance to the next smaller node.  */
5704               if (elt->left)
5705                 elt = elt->left;
5706               else
5707                 {
5708                   /* We have reached the smallest node bigger than the
5709                      current unfilled field.  Fill the space first.  */
5710                   next = elt->purpose;
5711                   break;
5712                 }
5713             }
5714           else
5715             {
5716               /* Advance to the next bigger node.  */
5717               if (elt->right)
5718                 elt = elt->right;
5719               else
5720                 {
5721                   /* We have reached the biggest node in a subtree.  Find
5722                      the parent of it, which is the next bigger node.  */
5723                   while (elt->parent && elt->parent->right == elt)
5724                     elt = elt->parent;
5725                   elt = elt->parent;
5726                   if (elt
5727                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
5728                                            bit_position (elt->purpose))))
5729                     {
5730                       next = elt->purpose;
5731                       break;
5732                     }
5733                 }
5734             }
5735         }
5736     }
5737
5738   /* Ordinarily return, but not if we want to output all
5739      and there are elements left.  */
5740   if (! (all && next != 0))
5741     return;
5742
5743   /* If it's not incremental, just skip over the gap, so that after
5744      jumping to retry we will output the next successive element.  */
5745   if (TREE_CODE (constructor_type) == RECORD_TYPE
5746       || TREE_CODE (constructor_type) == UNION_TYPE)
5747     constructor_unfilled_fields = next;
5748   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5749     constructor_unfilled_index = next;
5750
5751   /* ELT now points to the node in the pending tree with the next
5752      initializer to output.  */
5753   goto retry;
5754 }
5755 \f
5756 /* Add one non-braced element to the current constructor level.
5757    This adjusts the current position within the constructor's type.
5758    This may also start or terminate implicit levels
5759    to handle a partly-braced initializer.
5760
5761    Once this has found the correct level for the new element,
5762    it calls output_init_element.  */
5763
5764 void
5765 process_init_element (struct c_expr value)
5766 {
5767   tree orig_value = value.value;
5768   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
5769   bool strict_string = value.original_code == STRING_CST;
5770
5771   designator_depth = 0;
5772   designator_errorneous = 0;
5773
5774   /* Handle superfluous braces around string cst as in
5775      char x[] = {"foo"}; */
5776   if (string_flag
5777       && constructor_type
5778       && TREE_CODE (constructor_type) == ARRAY_TYPE
5779       && TREE_CODE (TREE_TYPE (constructor_type)) == INTEGER_TYPE
5780       && integer_zerop (constructor_unfilled_index))
5781     {
5782       if (constructor_stack->replacement_value.value)
5783         error_init ("excess elements in char array initializer");
5784       constructor_stack->replacement_value = value;
5785       return;
5786     }
5787
5788   if (constructor_stack->replacement_value.value != 0)
5789     {
5790       error_init ("excess elements in struct initializer");
5791       return;
5792     }
5793
5794   /* Ignore elements of a brace group if it is entirely superfluous
5795      and has already been diagnosed.  */
5796   if (constructor_type == 0)
5797     return;
5798
5799   /* If we've exhausted any levels that didn't have braces,
5800      pop them now.  */
5801   while (constructor_stack->implicit)
5802     {
5803       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5804            || TREE_CODE (constructor_type) == UNION_TYPE)
5805           && constructor_fields == 0)
5806         process_init_element (pop_init_level (1));
5807       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5808                && (constructor_max_index == 0
5809                    || tree_int_cst_lt (constructor_max_index,
5810                                        constructor_index)))
5811         process_init_element (pop_init_level (1));
5812       else
5813         break;
5814     }
5815
5816   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
5817   if (constructor_range_stack)
5818     {
5819       /* If value is a compound literal and we'll be just using its
5820          content, don't put it into a SAVE_EXPR.  */
5821       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
5822           || !require_constant_value
5823           || flag_isoc99)
5824         value.value = save_expr (value.value);
5825     }
5826
5827   while (1)
5828     {
5829       if (TREE_CODE (constructor_type) == RECORD_TYPE)
5830         {
5831           tree fieldtype;
5832           enum tree_code fieldcode;
5833
5834           if (constructor_fields == 0)
5835             {
5836               pedwarn_init ("excess elements in struct initializer");
5837               break;
5838             }
5839
5840           fieldtype = TREE_TYPE (constructor_fields);
5841           if (fieldtype != error_mark_node)
5842             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5843           fieldcode = TREE_CODE (fieldtype);
5844
5845           /* Error for non-static initialization of a flexible array member.  */
5846           if (fieldcode == ARRAY_TYPE
5847               && !require_constant_value
5848               && TYPE_SIZE (fieldtype) == NULL_TREE
5849               && TREE_CHAIN (constructor_fields) == NULL_TREE)
5850             {
5851               error_init ("non-static initialization of a flexible array member");
5852               break;
5853             }
5854
5855           /* Accept a string constant to initialize a subarray.  */
5856           if (value.value != 0
5857               && fieldcode == ARRAY_TYPE
5858               && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
5859               && string_flag)
5860             value.value = orig_value;
5861           /* Otherwise, if we have come to a subaggregate,
5862              and we don't have an element of its type, push into it.  */
5863           else if (value.value != 0 && !constructor_no_implicit
5864                    && value.value != error_mark_node
5865                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5866                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5867                        || fieldcode == UNION_TYPE))
5868             {
5869               push_init_level (1);
5870               continue;
5871             }
5872
5873           if (value.value)
5874             {
5875               push_member_name (constructor_fields);
5876               output_init_element (value.value, strict_string,
5877                                    fieldtype, constructor_fields, 1);
5878               RESTORE_SPELLING_DEPTH (constructor_depth);
5879             }
5880           else
5881             /* Do the bookkeeping for an element that was
5882                directly output as a constructor.  */
5883             {
5884               /* For a record, keep track of end position of last field.  */
5885               if (DECL_SIZE (constructor_fields))
5886                 constructor_bit_index
5887                   = size_binop (PLUS_EXPR,
5888                                 bit_position (constructor_fields),
5889                                 DECL_SIZE (constructor_fields));
5890
5891               /* If the current field was the first one not yet written out,
5892                  it isn't now, so update.  */
5893               if (constructor_unfilled_fields == constructor_fields)
5894                 {
5895                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5896                   /* Skip any nameless bit fields.  */
5897                   while (constructor_unfilled_fields != 0
5898                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5899                          && DECL_NAME (constructor_unfilled_fields) == 0)
5900                     constructor_unfilled_fields =
5901                       TREE_CHAIN (constructor_unfilled_fields);
5902                 }
5903             }
5904
5905           constructor_fields = TREE_CHAIN (constructor_fields);
5906           /* Skip any nameless bit fields at the beginning.  */
5907           while (constructor_fields != 0
5908                  && DECL_C_BIT_FIELD (constructor_fields)
5909                  && DECL_NAME (constructor_fields) == 0)
5910             constructor_fields = TREE_CHAIN (constructor_fields);
5911         }
5912       else if (TREE_CODE (constructor_type) == UNION_TYPE)
5913         {
5914           tree fieldtype;
5915           enum tree_code fieldcode;
5916
5917           if (constructor_fields == 0)
5918             {
5919               pedwarn_init ("excess elements in union initializer");
5920               break;
5921             }
5922
5923           fieldtype = TREE_TYPE (constructor_fields);
5924           if (fieldtype != error_mark_node)
5925             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5926           fieldcode = TREE_CODE (fieldtype);
5927
5928           /* Warn that traditional C rejects initialization of unions.
5929              We skip the warning if the value is zero.  This is done
5930              under the assumption that the zero initializer in user
5931              code appears conditioned on e.g. __STDC__ to avoid
5932              "missing initializer" warnings and relies on default
5933              initialization to zero in the traditional C case.
5934              We also skip the warning if the initializer is designated,
5935              again on the assumption that this must be conditional on
5936              __STDC__ anyway (and we've already complained about the
5937              member-designator already).  */
5938           if (warn_traditional && !in_system_header && !constructor_designated
5939               && !(value.value && (integer_zerop (value.value)
5940                                    || real_zerop (value.value))))
5941             warning ("traditional C rejects initialization of unions");
5942
5943           /* Accept a string constant to initialize a subarray.  */
5944           if (value.value != 0
5945               && fieldcode == ARRAY_TYPE
5946               && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
5947               && string_flag)
5948             value.value = orig_value;
5949           /* Otherwise, if we have come to a subaggregate,
5950              and we don't have an element of its type, push into it.  */
5951           else if (value.value != 0 && !constructor_no_implicit
5952                    && value.value != error_mark_node
5953                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5954                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5955                        || fieldcode == UNION_TYPE))
5956             {
5957               push_init_level (1);
5958               continue;
5959             }
5960
5961           if (value.value)
5962             {
5963               push_member_name (constructor_fields);
5964               output_init_element (value.value, strict_string,
5965                                    fieldtype, constructor_fields, 1);
5966               RESTORE_SPELLING_DEPTH (constructor_depth);
5967             }
5968           else
5969             /* Do the bookkeeping for an element that was
5970                directly output as a constructor.  */
5971             {
5972               constructor_bit_index = DECL_SIZE (constructor_fields);
5973               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5974             }
5975
5976           constructor_fields = 0;
5977         }
5978       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5979         {
5980           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5981           enum tree_code eltcode = TREE_CODE (elttype);
5982
5983           /* Accept a string constant to initialize a subarray.  */
5984           if (value.value != 0
5985               && eltcode == ARRAY_TYPE
5986               && TREE_CODE (TREE_TYPE (elttype)) == INTEGER_TYPE
5987               && string_flag)
5988             value.value = orig_value;
5989           /* Otherwise, if we have come to a subaggregate,
5990              and we don't have an element of its type, push into it.  */
5991           else if (value.value != 0 && !constructor_no_implicit
5992                    && value.value != error_mark_node
5993                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
5994                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
5995                        || eltcode == UNION_TYPE))
5996             {
5997               push_init_level (1);
5998               continue;
5999             }
6000
6001           if (constructor_max_index != 0
6002               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6003                   || integer_all_onesp (constructor_max_index)))
6004             {
6005               pedwarn_init ("excess elements in array initializer");
6006               break;
6007             }
6008
6009           /* Now output the actual element.  */
6010           if (value.value)
6011             {
6012               push_array_bounds (tree_low_cst (constructor_index, 0));
6013               output_init_element (value.value, strict_string,
6014                                    elttype, constructor_index, 1);
6015               RESTORE_SPELLING_DEPTH (constructor_depth);
6016             }
6017
6018           constructor_index
6019             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6020
6021           if (!value.value)
6022             /* If we are doing the bookkeeping for an element that was
6023                directly output as a constructor, we must update
6024                constructor_unfilled_index.  */
6025             constructor_unfilled_index = constructor_index;
6026         }
6027       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6028         {
6029           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6030
6031          /* Do a basic check of initializer size.  Note that vectors
6032             always have a fixed size derived from their type.  */
6033           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6034             {
6035               pedwarn_init ("excess elements in vector initializer");
6036               break;
6037             }
6038
6039           /* Now output the actual element.  */
6040           if (value.value)
6041             output_init_element (value.value, strict_string,
6042                                  elttype, constructor_index, 1);
6043
6044           constructor_index
6045             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6046
6047           if (!value.value)
6048             /* If we are doing the bookkeeping for an element that was
6049                directly output as a constructor, we must update
6050                constructor_unfilled_index.  */
6051             constructor_unfilled_index = constructor_index;
6052         }
6053
6054       /* Handle the sole element allowed in a braced initializer
6055          for a scalar variable.  */
6056       else if (constructor_fields == 0)
6057         {
6058           pedwarn_init ("excess elements in scalar initializer");
6059           break;
6060         }
6061       else
6062         {
6063           if (value.value)
6064             output_init_element (value.value, strict_string,
6065                                  constructor_type, NULL_TREE, 1);
6066           constructor_fields = 0;
6067         }
6068
6069       /* Handle range initializers either at this level or anywhere higher
6070          in the designator stack.  */
6071       if (constructor_range_stack)
6072         {
6073           struct constructor_range_stack *p, *range_stack;
6074           int finish = 0;
6075
6076           range_stack = constructor_range_stack;
6077           constructor_range_stack = 0;
6078           while (constructor_stack != range_stack->stack)
6079             {
6080               if (!constructor_stack->implicit)
6081                 abort ();
6082               process_init_element (pop_init_level (1));
6083             }
6084           for (p = range_stack;
6085                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6086                p = p->prev)
6087             {
6088               if (!constructor_stack->implicit)
6089                 abort ();
6090               process_init_element (pop_init_level (1));
6091             }
6092
6093           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6094           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6095             finish = 1;
6096
6097           while (1)
6098             {
6099               constructor_index = p->index;
6100               constructor_fields = p->fields;
6101               if (finish && p->range_end && p->index == p->range_start)
6102                 {
6103                   finish = 0;
6104                   p->prev = 0;
6105                 }
6106               p = p->next;
6107               if (!p)
6108                 break;
6109               push_init_level (2);
6110               p->stack = constructor_stack;
6111               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6112                 p->index = p->range_start;
6113             }
6114
6115           if (!finish)
6116             constructor_range_stack = range_stack;
6117           continue;
6118         }
6119
6120       break;
6121     }
6122
6123   constructor_range_stack = 0;
6124 }
6125 \f
6126 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6127    (guaranteed to be 'volatile' or null) and ARGS (represented using
6128    an ASM_EXPR node).  */
6129 tree
6130 build_asm_stmt (tree cv_qualifier, tree args)
6131 {
6132   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6133     ASM_VOLATILE_P (args) = 1;
6134   return add_stmt (args);
6135 }
6136
6137 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6138    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6139    SIMPLE indicates whether there was anything at all after the
6140    string in the asm expression -- asm("blah") and asm("blah" : )
6141    are subtly different.  We use a ASM_EXPR node to represent this.  */
6142 tree
6143 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6144                 bool simple)
6145 {
6146   tree tail;
6147   tree args;
6148   int i;
6149   const char *constraint;
6150   bool allows_mem, allows_reg, is_inout;
6151   int ninputs;
6152   int noutputs;
6153
6154   ninputs = list_length (inputs);
6155   noutputs = list_length (outputs);
6156
6157   /* Remove output conversions that change the type but not the mode.  */
6158   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6159     {
6160       tree output = TREE_VALUE (tail);
6161       STRIP_NOPS (output);
6162       TREE_VALUE (tail) = output;
6163       lvalue_or_else (output, "invalid lvalue in asm statement");
6164
6165       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6166
6167       if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
6168                                     &allows_mem, &allows_reg, &is_inout))
6169         {
6170           /* By marking this operand as erroneous, we will not try
6171           to process this operand again in expand_asm_operands.  */
6172           TREE_VALUE (tail) = error_mark_node;
6173           continue;
6174         }
6175
6176       /* If the operand is a DECL that is going to end up in
6177         memory, assume it is addressable.  This is a bit more
6178         conservative than it would ideally be; the exact test is
6179         buried deep in expand_asm_operands and depends on the
6180         DECL_RTL for the OPERAND -- which we don't have at this
6181         point.  */
6182       if (!allows_reg && DECL_P (output))
6183         c_mark_addressable (output);
6184     }
6185
6186   /* Perform default conversions on array and function inputs.
6187      Don't do this for other types as it would screw up operands
6188      expected to be in memory.  */
6189   for (tail = inputs; tail; tail = TREE_CHAIN (tail))
6190     TREE_VALUE (tail) = default_function_array_conversion (TREE_VALUE (tail));
6191
6192   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6193
6194   /* Simple asm statements are treated as volatile.  */
6195   if (simple)
6196     {
6197       ASM_VOLATILE_P (args) = 1;
6198       ASM_INPUT_P (args) = 1;
6199     }
6200   return args;
6201 }
6202 \f
6203 /* Generate a goto statement to LABEL.  */
6204
6205 tree
6206 c_finish_goto_label (tree label)
6207 {
6208   tree decl = lookup_label (label);
6209   if (!decl)
6210     return NULL_TREE;
6211
6212   TREE_USED (decl) = 1;
6213   return add_stmt (build (GOTO_EXPR, void_type_node, decl));
6214 }
6215
6216 /* Generate a computed goto statement to EXPR.  */
6217
6218 tree
6219 c_finish_goto_ptr (tree expr)
6220 {
6221   if (pedantic)
6222     pedwarn ("ISO C forbids `goto *expr;'");
6223   expr = convert (ptr_type_node, expr);
6224   return add_stmt (build (GOTO_EXPR, void_type_node, expr));
6225 }
6226
6227 /* Generate a C `return' statement.  RETVAL is the expression for what
6228    to return, or a null pointer for `return;' with no value.  */
6229
6230 tree
6231 c_finish_return (tree retval)
6232 {
6233   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6234
6235   if (TREE_THIS_VOLATILE (current_function_decl))
6236     warning ("function declared `noreturn' has a `return' statement");
6237
6238   if (!retval)
6239     {
6240       current_function_returns_null = 1;
6241       if ((warn_return_type || flag_isoc99)
6242           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6243         pedwarn_c99 ("`return' with no value, in function returning non-void");
6244     }
6245   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6246     {
6247       current_function_returns_null = 1;
6248       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6249         pedwarn ("`return' with a value, in function returning void");
6250     }
6251   else
6252     {
6253       tree t = convert_for_assignment (valtype, retval, _("return"),
6254                                        NULL_TREE, NULL_TREE, 0);
6255       tree res = DECL_RESULT (current_function_decl);
6256       tree inner;
6257
6258       current_function_returns_value = 1;
6259       if (t == error_mark_node)
6260         return NULL_TREE;
6261
6262       inner = t = convert (TREE_TYPE (res), t);
6263
6264       /* Strip any conversions, additions, and subtractions, and see if
6265          we are returning the address of a local variable.  Warn if so.  */
6266       while (1)
6267         {
6268           switch (TREE_CODE (inner))
6269             {
6270             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6271             case PLUS_EXPR:
6272               inner = TREE_OPERAND (inner, 0);
6273               continue;
6274
6275             case MINUS_EXPR:
6276               /* If the second operand of the MINUS_EXPR has a pointer
6277                  type (or is converted from it), this may be valid, so
6278                  don't give a warning.  */
6279               {
6280                 tree op1 = TREE_OPERAND (inner, 1);
6281
6282                 while (! POINTER_TYPE_P (TREE_TYPE (op1))
6283                        && (TREE_CODE (op1) == NOP_EXPR
6284                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6285                            || TREE_CODE (op1) == CONVERT_EXPR))
6286                   op1 = TREE_OPERAND (op1, 0);
6287
6288                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6289                   break;
6290
6291                 inner = TREE_OPERAND (inner, 0);
6292                 continue;
6293               }
6294
6295             case ADDR_EXPR:
6296               inner = TREE_OPERAND (inner, 0);
6297
6298               while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
6299                 inner = TREE_OPERAND (inner, 0);
6300
6301               if (DECL_P (inner)
6302                   && ! DECL_EXTERNAL (inner)
6303                   && ! TREE_STATIC (inner)
6304                   && DECL_CONTEXT (inner) == current_function_decl)
6305                 warning ("function returns address of local variable");
6306               break;
6307
6308             default:
6309               break;
6310             }
6311
6312           break;
6313         }
6314
6315       retval = build (MODIFY_EXPR, TREE_TYPE (res), res, t);
6316     }
6317
6318   return add_stmt (build_stmt (RETURN_EXPR, retval));
6319 }
6320 \f
6321 struct c_switch {
6322   /* The SWITCH_STMT being built.  */
6323   tree switch_stmt;
6324
6325   /* The original type of the testing expression, ie. before the
6326      default conversion is applied.  */
6327   tree orig_type;
6328
6329   /* A splay-tree mapping the low element of a case range to the high
6330      element, or NULL_TREE if there is no high element.  Used to
6331      determine whether or not a new case label duplicates an old case
6332      label.  We need a tree, rather than simply a hash table, because
6333      of the GNU case range extension.  */
6334   splay_tree cases;
6335
6336   /* The next node on the stack.  */
6337   struct c_switch *next;
6338 };
6339
6340 /* A stack of the currently active switch statements.  The innermost
6341    switch statement is on the top of the stack.  There is no need to
6342    mark the stack for garbage collection because it is only active
6343    during the processing of the body of a function, and we never
6344    collect at that point.  */
6345
6346 struct c_switch *c_switch_stack;
6347
6348 /* Start a C switch statement, testing expression EXP.  Return the new
6349    SWITCH_STMT.  */
6350
6351 tree
6352 c_start_case (tree exp)
6353 {
6354   enum tree_code code;
6355   tree type, orig_type = error_mark_node;
6356   struct c_switch *cs;
6357
6358   if (exp != error_mark_node)
6359     {
6360       code = TREE_CODE (TREE_TYPE (exp));
6361       orig_type = TREE_TYPE (exp);
6362
6363       if (! INTEGRAL_TYPE_P (orig_type)
6364           && code != ERROR_MARK)
6365         {
6366           error ("switch quantity not an integer");
6367           exp = integer_zero_node;
6368         }
6369       else
6370         {
6371           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6372
6373           if (warn_traditional && !in_system_header
6374               && (type == long_integer_type_node
6375                   || type == long_unsigned_type_node))
6376             warning ("`long' switch expression not converted to `int' in ISO C");
6377
6378           exp = default_conversion (exp);
6379           type = TREE_TYPE (exp);
6380         }
6381     }
6382
6383   /* Add this new SWITCH_STMT to the stack.  */
6384   cs = xmalloc (sizeof (*cs));
6385   cs->switch_stmt = build_stmt (SWITCH_STMT, exp, NULL_TREE, orig_type);
6386   cs->orig_type = orig_type;
6387   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6388   cs->next = c_switch_stack;
6389   c_switch_stack = cs;
6390
6391   return add_stmt (cs->switch_stmt);
6392 }
6393
6394 /* Process a case label.  */
6395
6396 tree
6397 do_case (tree low_value, tree high_value)
6398 {
6399   tree label = NULL_TREE;
6400
6401   if (c_switch_stack)
6402     {
6403       label = c_add_case_label (c_switch_stack->cases,
6404                                 SWITCH_COND (c_switch_stack->switch_stmt),
6405                                 c_switch_stack->orig_type,
6406                                 low_value, high_value);
6407       if (label == error_mark_node)
6408         label = NULL_TREE;
6409     }
6410   else if (low_value)
6411     error ("case label not within a switch statement");
6412   else
6413     error ("`default' label not within a switch statement");
6414
6415   return label;
6416 }
6417
6418 /* Finish the switch statement.  */
6419
6420 void
6421 c_finish_case (tree body)
6422 {
6423   struct c_switch *cs = c_switch_stack;
6424
6425   SWITCH_BODY (cs->switch_stmt) = body;
6426
6427   /* Emit warnings as needed.  */
6428   c_do_switch_warnings (cs->cases, cs->switch_stmt);
6429
6430   /* Pop the stack.  */
6431   c_switch_stack = cs->next;
6432   splay_tree_delete (cs->cases);
6433   free (cs);
6434 }
6435 \f
6436 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6437    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6438    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6439    statement, and was not surrounded with parenthesis.  */
6440
6441 void
6442 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6443                   tree else_block, bool nested_if)
6444 {
6445   tree stmt;
6446
6447   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6448   if (warn_parentheses && nested_if && else_block == NULL)
6449     {
6450       tree inner_if = then_block;
6451
6452       /* We know from the grammar productions that there is an IF nested
6453          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6454          it might not be exactly THEN_BLOCK, but should be the last
6455          non-container statement within.  */
6456       while (1)
6457         switch (TREE_CODE (inner_if))
6458           {
6459           case COND_EXPR:
6460             goto found;
6461           case BIND_EXPR:
6462             inner_if = BIND_EXPR_BODY (inner_if);
6463             break;
6464           case STATEMENT_LIST:
6465             inner_if = expr_last (then_block);
6466             break;
6467           case TRY_FINALLY_EXPR:
6468           case TRY_CATCH_EXPR:
6469             inner_if = TREE_OPERAND (inner_if, 0);
6470             break;
6471           default:
6472             abort ();
6473           }
6474     found:
6475
6476       if (COND_EXPR_ELSE (inner_if))
6477          warning ("%Hsuggest explicit braces to avoid ambiguous `else'",
6478                   &if_locus);
6479     }
6480
6481   /* Diagnose ";" via the special empty statement node that we create.  */
6482   if (extra_warnings)
6483     {
6484       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6485         {
6486           if (!else_block)
6487             warning ("%Hempty body in an if-statement",
6488                      EXPR_LOCUS (then_block));
6489           then_block = alloc_stmt_list ();
6490         }
6491       if (else_block
6492           && TREE_CODE (else_block) == NOP_EXPR
6493           && !TREE_TYPE (else_block))
6494         {
6495           warning ("%Hempty body in an else-statement",
6496                    EXPR_LOCUS (else_block));
6497           else_block = alloc_stmt_list ();
6498         }
6499     }
6500
6501   stmt = build3 (COND_EXPR, NULL_TREE, cond, then_block, else_block);
6502   SET_EXPR_LOCATION (stmt, if_locus);
6503   add_stmt (stmt);
6504 }
6505
6506 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6507    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6508    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6509    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6510    the continue label.  Everything is allowed to be NULL.  */
6511
6512 void
6513 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6514                tree blab, tree clab, bool cond_is_first)
6515 {
6516   tree entry = NULL, exit = NULL, t;
6517
6518   /* Detect do { ... } while (0) and don't generate loop construct.  */
6519   if (cond && !cond_is_first && integer_zerop (cond))
6520     cond = NULL;
6521   if (cond_is_first || cond)
6522     {
6523       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6524
6525       /* If we have an exit condition, then we build an IF with gotos either
6526          out of the loop, or to the top of it.  If there's no exit condition,
6527          then we just build a jump back to the top.  */
6528       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6529
6530       if (cond)
6531         {
6532           /* Canonicalize the loop condition to the end.  This means
6533              generating a branch to the loop condition.  Reuse the
6534              continue label, if possible.  */
6535           if (cond_is_first)
6536             {
6537               if (incr || !clab)
6538                 {
6539                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6540                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6541                 }
6542               else
6543                 t = build1 (GOTO_EXPR, void_type_node, clab);
6544               SET_EXPR_LOCATION (t, start_locus);
6545               add_stmt (t);
6546             }
6547
6548           t = build_and_jump (&blab);
6549           exit = build (COND_EXPR, void_type_node, cond, exit, t);
6550           exit = fold (exit);
6551           if (cond_is_first)
6552             SET_EXPR_LOCATION (exit, start_locus);
6553           else
6554             SET_EXPR_LOCATION (exit, input_location);
6555         }
6556
6557       add_stmt (top);
6558     }
6559
6560   if (body)
6561     add_stmt (body);
6562   if (clab)
6563     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
6564   if (incr)
6565     add_stmt (incr);
6566   if (entry)
6567     add_stmt (entry);
6568   if (exit)
6569     add_stmt (exit);
6570   if (blab)
6571     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
6572 }
6573
6574 tree
6575 c_finish_bc_stmt (tree *label_p, bool is_break)
6576 {
6577   tree label = *label_p;
6578
6579   if (!label)
6580     *label_p = label = create_artificial_label ();
6581   else if (TREE_CODE (label) != LABEL_DECL)
6582     {
6583       if (is_break)
6584         error ("break statement not within loop or switch");
6585       else
6586         error ("continue statement not within a loop");
6587       return NULL_TREE;
6588     }
6589
6590   return add_stmt (build (GOTO_EXPR, void_type_node, label));
6591 }
6592
6593 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
6594
6595 static void
6596 emit_side_effect_warnings (tree expr)
6597 {
6598   if (expr == error_mark_node)
6599     ;
6600   else if (!TREE_SIDE_EFFECTS (expr))
6601     {
6602       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
6603         warning ("%Hstatement with no effect",
6604                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
6605     }
6606   else if (warn_unused_value)
6607     warn_if_unused_value (expr, input_location);
6608 }
6609
6610 /* Process an expression as if it were a complete statement.  Emit
6611    diagnostics, but do not call ADD_STMT.  */
6612
6613 tree
6614 c_process_expr_stmt (tree expr)
6615 {
6616   if (!expr)
6617     return NULL_TREE;
6618
6619   /* Do default conversion if safe and possibly important,
6620      in case within ({...}).  */
6621   if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
6622        && (flag_isoc99 || lvalue_p (expr)))
6623       || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE)
6624     expr = default_conversion (expr);
6625
6626   if (warn_sequence_point)
6627     verify_sequence_points (expr);
6628
6629   if (TREE_TYPE (expr) != error_mark_node
6630       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
6631       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
6632     error ("expression statement has incomplete type");
6633
6634   /* If we're not processing a statement expression, warn about unused values.
6635      Warnings for statement expressions will be emitted later, once we figure
6636      out which is the result.  */
6637   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6638       && (extra_warnings || warn_unused_value))
6639     emit_side_effect_warnings (expr);
6640
6641   /* If the expression is not of a type to which we cannot assign a line
6642      number, wrap the thing in a no-op NOP_EXPR.  */
6643   if (DECL_P (expr) || TREE_CODE_CLASS (TREE_CODE (expr)) == 'c')
6644     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
6645
6646   if (EXPR_P (expr))
6647     SET_EXPR_LOCATION (expr, input_location);
6648
6649   return expr;
6650 }
6651
6652 /* Emit an expression as a statement.  */
6653
6654 tree
6655 c_finish_expr_stmt (tree expr)
6656 {
6657   if (expr)
6658     return add_stmt (c_process_expr_stmt (expr));
6659   else
6660     return NULL;
6661 }
6662
6663 /* Do the opposite and emit a statement as an expression.  To begin,
6664    create a new binding level and return it.  */
6665
6666 tree
6667 c_begin_stmt_expr (void)
6668 {
6669   tree ret;
6670
6671   /* We must force a BLOCK for this level so that, if it is not expanded
6672      later, there is a way to turn off the entire subtree of blocks that
6673      are contained in it.  */
6674   keep_next_level ();
6675   ret = c_begin_compound_stmt (true);
6676
6677   /* Mark the current statement list as belonging to a statement list.  */
6678   STATEMENT_LIST_STMT_EXPR (ret) = 1;
6679
6680   return ret;
6681 }
6682
6683 tree
6684 c_finish_stmt_expr (tree body)
6685 {
6686   tree last, type, tmp, val;
6687   tree *last_p;
6688
6689   body = c_end_compound_stmt (body, true);
6690
6691   /* Locate the last statement in BODY.  See c_end_compound_stmt
6692      about always returning a BIND_EXPR.  */
6693   last_p = &BIND_EXPR_BODY (body);
6694   last = BIND_EXPR_BODY (body);
6695
6696  continue_searching:
6697   if (TREE_CODE (last) == STATEMENT_LIST)
6698     {
6699       tree_stmt_iterator i;
6700
6701       /* This can happen with degenerate cases like ({ }).  No value.  */
6702       if (!TREE_SIDE_EFFECTS (last))
6703         return body;
6704
6705       /* If we're supposed to generate side effects warnings, process
6706          all of the statements except the last.  */
6707       if (extra_warnings || warn_unused_value)
6708         {
6709           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
6710             emit_side_effect_warnings (tsi_stmt (i));
6711         }
6712       else
6713         i = tsi_last (last);
6714       last_p = tsi_stmt_ptr (i);
6715       last = *last_p;
6716     }
6717
6718   /* If the end of the list is exception related, then the list was split
6719      by a call to push_cleanup.  Continue searching.  */
6720   if (TREE_CODE (last) == TRY_FINALLY_EXPR
6721       || TREE_CODE (last) == TRY_CATCH_EXPR)
6722     {
6723       last_p = &TREE_OPERAND (last, 0);
6724       last = *last_p;
6725       goto continue_searching;
6726     }
6727
6728   /* In the case that the BIND_EXPR is not necessary, return the
6729      expression out from inside it.  */
6730   if (last == error_mark_node
6731       || (last == BIND_EXPR_BODY (body)
6732           && BIND_EXPR_VARS (body) == NULL))
6733     return last;
6734
6735   /* Extract the type of said expression.  */
6736   type = TREE_TYPE (last);
6737
6738   /* If we're not returning a value at all, then the BIND_EXPR that
6739      we already have is a fine expression to return.  */
6740   if (!type || VOID_TYPE_P (type))
6741     return body;
6742
6743   /* Now that we've located the expression containing the value, it seems
6744      silly to make voidify_wrapper_expr repeat the process.  Create a
6745      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
6746   tmp = create_tmp_var_raw (type, NULL);
6747
6748   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
6749      tree_expr_nonnegative_p giving up immediately.  */
6750   val = last;
6751   if (TREE_CODE (val) == NOP_EXPR
6752       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
6753     val = TREE_OPERAND (val, 0);
6754
6755   *last_p = build (MODIFY_EXPR, void_type_node, tmp, val);
6756   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
6757
6758   return build (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
6759 }
6760 \f
6761 /* Begin and end compound statements.  This is as simple as pushing
6762    and popping new statement lists from the tree.  */
6763
6764 tree
6765 c_begin_compound_stmt (bool do_scope)
6766 {
6767   tree stmt = push_stmt_list ();
6768   if (do_scope)
6769     push_scope ();
6770   return stmt;
6771 }
6772
6773 tree
6774 c_end_compound_stmt (tree stmt, bool do_scope)
6775 {
6776   tree block = NULL;
6777
6778   if (do_scope)
6779     {
6780       if (c_dialect_objc ())
6781         objc_clear_super_receiver ();
6782       block = pop_scope ();
6783     }
6784
6785   stmt = pop_stmt_list (stmt);
6786   stmt = c_build_bind_expr (block, stmt);
6787
6788   /* If this compound statement is nested immediately inside a statement
6789      expression, then force a BIND_EXPR to be created.  Otherwise we'll
6790      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
6791      STATEMENT_LISTs merge, and thus we can lose track of what statement
6792      was really last.  */
6793   if (cur_stmt_list
6794       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6795       && TREE_CODE (stmt) != BIND_EXPR)
6796     {
6797       stmt = build (BIND_EXPR, void_type_node, NULL, stmt, NULL);
6798       TREE_SIDE_EFFECTS (stmt) = 1;
6799     }
6800
6801   return stmt;
6802 }
6803
6804 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
6805    when the current scope is exited.  EH_ONLY is true when this is not
6806    meant to apply to normal control flow transfer.  */
6807
6808 void
6809 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
6810 {
6811   enum tree_code code;
6812   tree stmt, list;
6813   bool stmt_expr;
6814
6815   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
6816   stmt = build_stmt (code, NULL, cleanup);
6817   add_stmt (stmt);
6818   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
6819   list = push_stmt_list ();
6820   TREE_OPERAND (stmt, 0) = list;
6821   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
6822 }
6823 \f
6824 /* Build a binary-operation expression without default conversions.
6825    CODE is the kind of expression to build.
6826    This function differs from `build' in several ways:
6827    the data type of the result is computed and recorded in it,
6828    warnings are generated if arg data types are invalid,
6829    special handling for addition and subtraction of pointers is known,
6830    and some optimization is done (operations on narrow ints
6831    are done in the narrower type when that gives the same result).
6832    Constant folding is also done before the result is returned.
6833
6834    Note that the operands will never have enumeral types, or function
6835    or array types, because either they will have the default conversions
6836    performed or they have both just been converted to some other type in which
6837    the arithmetic is to be done.  */
6838
6839 tree
6840 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
6841                  int convert_p)
6842 {
6843   tree type0, type1;
6844   enum tree_code code0, code1;
6845   tree op0, op1;
6846
6847   /* Expression code to give to the expression when it is built.
6848      Normally this is CODE, which is what the caller asked for,
6849      but in some special cases we change it.  */
6850   enum tree_code resultcode = code;
6851
6852   /* Data type in which the computation is to be performed.
6853      In the simplest cases this is the common type of the arguments.  */
6854   tree result_type = NULL;
6855
6856   /* Nonzero means operands have already been type-converted
6857      in whatever way is necessary.
6858      Zero means they need to be converted to RESULT_TYPE.  */
6859   int converted = 0;
6860
6861   /* Nonzero means create the expression with this type, rather than
6862      RESULT_TYPE.  */
6863   tree build_type = 0;
6864
6865   /* Nonzero means after finally constructing the expression
6866      convert it to this type.  */
6867   tree final_type = 0;
6868
6869   /* Nonzero if this is an operation like MIN or MAX which can
6870      safely be computed in short if both args are promoted shorts.
6871      Also implies COMMON.
6872      -1 indicates a bitwise operation; this makes a difference
6873      in the exact conditions for when it is safe to do the operation
6874      in a narrower mode.  */
6875   int shorten = 0;
6876
6877   /* Nonzero if this is a comparison operation;
6878      if both args are promoted shorts, compare the original shorts.
6879      Also implies COMMON.  */
6880   int short_compare = 0;
6881
6882   /* Nonzero if this is a right-shift operation, which can be computed on the
6883      original short and then promoted if the operand is a promoted short.  */
6884   int short_shift = 0;
6885
6886   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
6887   int common = 0;
6888
6889   if (convert_p)
6890     {
6891       op0 = default_conversion (orig_op0);
6892       op1 = default_conversion (orig_op1);
6893     }
6894   else
6895     {
6896       op0 = orig_op0;
6897       op1 = orig_op1;
6898     }
6899
6900   type0 = TREE_TYPE (op0);
6901   type1 = TREE_TYPE (op1);
6902
6903   /* The expression codes of the data types of the arguments tell us
6904      whether the arguments are integers, floating, pointers, etc.  */
6905   code0 = TREE_CODE (type0);
6906   code1 = TREE_CODE (type1);
6907
6908   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
6909   STRIP_TYPE_NOPS (op0);
6910   STRIP_TYPE_NOPS (op1);
6911
6912   /* If an error was already reported for one of the arguments,
6913      avoid reporting another error.  */
6914
6915   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
6916     return error_mark_node;
6917
6918   switch (code)
6919     {
6920     case PLUS_EXPR:
6921       /* Handle the pointer + int case.  */
6922       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6923         return pointer_int_sum (PLUS_EXPR, op0, op1);
6924       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
6925         return pointer_int_sum (PLUS_EXPR, op1, op0);
6926       else
6927         common = 1;
6928       break;
6929
6930     case MINUS_EXPR:
6931       /* Subtraction of two similar pointers.
6932          We must subtract them as integers, then divide by object size.  */
6933       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
6934           && comp_target_types (type0, type1, 1))
6935         return pointer_diff (op0, op1);
6936       /* Handle pointer minus int.  Just like pointer plus int.  */
6937       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6938         return pointer_int_sum (MINUS_EXPR, op0, op1);
6939       else
6940         common = 1;
6941       break;
6942
6943     case MULT_EXPR:
6944       common = 1;
6945       break;
6946
6947     case TRUNC_DIV_EXPR:
6948     case CEIL_DIV_EXPR:
6949     case FLOOR_DIV_EXPR:
6950     case ROUND_DIV_EXPR:
6951     case EXACT_DIV_EXPR:
6952       /* Floating point division by zero is a legitimate way to obtain
6953          infinities and NaNs.  */
6954       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6955         warning ("division by zero");
6956
6957       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
6958            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6959           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
6960               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
6961         {
6962           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6963             code0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
6964           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
6965             code1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
6966
6967           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
6968             resultcode = RDIV_EXPR;
6969           else
6970             /* Although it would be tempting to shorten always here, that
6971                loses on some targets, since the modulo instruction is
6972                undefined if the quotient can't be represented in the
6973                computation mode.  We shorten only if unsigned or if
6974                dividing by something we know != -1.  */
6975             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
6976                        || (TREE_CODE (op1) == INTEGER_CST
6977                            && ! integer_all_onesp (op1)));
6978           common = 1;
6979         }
6980       break;
6981
6982     case BIT_AND_EXPR:
6983     case BIT_IOR_EXPR:
6984     case BIT_XOR_EXPR:
6985       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
6986         shorten = -1;
6987       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
6988         common = 1;
6989       break;
6990
6991     case TRUNC_MOD_EXPR:
6992     case FLOOR_MOD_EXPR:
6993       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6994         warning ("division by zero");
6995
6996       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
6997         {
6998           /* Although it would be tempting to shorten always here, that loses
6999              on some targets, since the modulo instruction is undefined if the
7000              quotient can't be represented in the computation mode.  We shorten
7001              only if unsigned or if dividing by something we know != -1.  */
7002           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7003                      || (TREE_CODE (op1) == INTEGER_CST
7004                          && ! integer_all_onesp (op1)));
7005           common = 1;
7006         }
7007       break;
7008
7009     case TRUTH_ANDIF_EXPR:
7010     case TRUTH_ORIF_EXPR:
7011     case TRUTH_AND_EXPR:
7012     case TRUTH_OR_EXPR:
7013     case TRUTH_XOR_EXPR:
7014       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7015            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7016           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7017               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7018         {
7019           /* Result of these operations is always an int,
7020              but that does not mean the operands should be
7021              converted to ints!  */
7022           result_type = integer_type_node;
7023           op0 = lang_hooks.truthvalue_conversion (op0);
7024           op1 = lang_hooks.truthvalue_conversion (op1);
7025           converted = 1;
7026         }
7027       break;
7028
7029       /* Shift operations: result has same type as first operand;
7030          always convert second operand to int.
7031          Also set SHORT_SHIFT if shifting rightward.  */
7032
7033     case RSHIFT_EXPR:
7034       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7035         {
7036           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7037             {
7038               if (tree_int_cst_sgn (op1) < 0)
7039                 warning ("right shift count is negative");
7040               else
7041                 {
7042                   if (! integer_zerop (op1))
7043                     short_shift = 1;
7044
7045                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7046                     warning ("right shift count >= width of type");
7047                 }
7048             }
7049
7050           /* Use the type of the value to be shifted.  */
7051           result_type = type0;
7052           /* Convert the shift-count to an integer, regardless of size
7053              of value being shifted.  */
7054           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7055             op1 = convert (integer_type_node, op1);
7056           /* Avoid converting op1 to result_type later.  */
7057           converted = 1;
7058         }
7059       break;
7060
7061     case LSHIFT_EXPR:
7062       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7063         {
7064           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7065             {
7066               if (tree_int_cst_sgn (op1) < 0)
7067                 warning ("left shift count is negative");
7068
7069               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7070                 warning ("left shift count >= width of type");
7071             }
7072
7073           /* Use the type of the value to be shifted.  */
7074           result_type = type0;
7075           /* Convert the shift-count to an integer, regardless of size
7076              of value being shifted.  */
7077           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7078             op1 = convert (integer_type_node, op1);
7079           /* Avoid converting op1 to result_type later.  */
7080           converted = 1;
7081         }
7082       break;
7083
7084     case RROTATE_EXPR:
7085     case LROTATE_EXPR:
7086       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7087         {
7088           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7089             {
7090               if (tree_int_cst_sgn (op1) < 0)
7091                 warning ("shift count is negative");
7092               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7093                 warning ("shift count >= width of type");
7094             }
7095
7096           /* Use the type of the value to be shifted.  */
7097           result_type = type0;
7098           /* Convert the shift-count to an integer, regardless of size
7099              of value being shifted.  */
7100           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7101             op1 = convert (integer_type_node, op1);
7102           /* Avoid converting op1 to result_type later.  */
7103           converted = 1;
7104         }
7105       break;
7106
7107     case EQ_EXPR:
7108     case NE_EXPR:
7109       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
7110         warning ("comparing floating point with == or != is unsafe");
7111       /* Result of comparison is always int,
7112          but don't convert the args to int!  */
7113       build_type = integer_type_node;
7114       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7115            || code0 == COMPLEX_TYPE)
7116           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7117               || code1 == COMPLEX_TYPE))
7118         short_compare = 1;
7119       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7120         {
7121           tree tt0 = TREE_TYPE (type0);
7122           tree tt1 = TREE_TYPE (type1);
7123           /* Anything compares with void *.  void * compares with anything.
7124              Otherwise, the targets must be compatible
7125              and both must be object or both incomplete.  */
7126           if (comp_target_types (type0, type1, 1))
7127             result_type = common_pointer_type (type0, type1);
7128           else if (VOID_TYPE_P (tt0))
7129             {
7130               /* op0 != orig_op0 detects the case of something
7131                  whose value is 0 but which isn't a valid null ptr const.  */
7132               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7133                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7134                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7135             }
7136           else if (VOID_TYPE_P (tt1))
7137             {
7138               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7139                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7140                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7141             }
7142           else
7143             pedwarn ("comparison of distinct pointer types lacks a cast");
7144
7145           if (result_type == NULL_TREE)
7146             result_type = ptr_type_node;
7147         }
7148       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7149                && integer_zerop (op1))
7150         result_type = type0;
7151       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7152                && integer_zerop (op0))
7153         result_type = type1;
7154       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7155         {
7156           result_type = type0;
7157           pedwarn ("comparison between pointer and integer");
7158         }
7159       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7160         {
7161           result_type = type1;
7162           pedwarn ("comparison between pointer and integer");
7163         }
7164       break;
7165
7166     case MAX_EXPR:
7167     case MIN_EXPR:
7168       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7169           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7170         shorten = 1;
7171       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7172         {
7173           if (comp_target_types (type0, type1, 1))
7174             {
7175               result_type = common_pointer_type (type0, type1);
7176               if (pedantic
7177                   && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7178                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7179             }
7180           else
7181             {
7182               result_type = ptr_type_node;
7183               pedwarn ("comparison of distinct pointer types lacks a cast");
7184             }
7185         }
7186       break;
7187
7188     case LE_EXPR:
7189     case GE_EXPR:
7190     case LT_EXPR:
7191     case GT_EXPR:
7192       build_type = integer_type_node;
7193       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7194           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7195         short_compare = 1;
7196       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7197         {
7198           if (comp_target_types (type0, type1, 1))
7199             {
7200               result_type = common_pointer_type (type0, type1);
7201               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7202                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7203                 pedwarn ("comparison of complete and incomplete pointers");
7204               else if (pedantic
7205                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7206                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7207             }
7208           else
7209             {
7210               result_type = ptr_type_node;
7211               pedwarn ("comparison of distinct pointer types lacks a cast");
7212             }
7213         }
7214       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7215                && integer_zerop (op1))
7216         {
7217           result_type = type0;
7218           if (pedantic || extra_warnings)
7219             pedwarn ("ordered comparison of pointer with integer zero");
7220         }
7221       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7222                && integer_zerop (op0))
7223         {
7224           result_type = type1;
7225           if (pedantic)
7226             pedwarn ("ordered comparison of pointer with integer zero");
7227         }
7228       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7229         {
7230           result_type = type0;
7231           pedwarn ("comparison between pointer and integer");
7232         }
7233       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7234         {
7235           result_type = type1;
7236           pedwarn ("comparison between pointer and integer");
7237         }
7238       break;
7239
7240     case UNORDERED_EXPR:
7241     case ORDERED_EXPR:
7242     case UNLT_EXPR:
7243     case UNLE_EXPR:
7244     case UNGT_EXPR:
7245     case UNGE_EXPR:
7246     case UNEQ_EXPR:
7247     case LTGT_EXPR:
7248       build_type = integer_type_node;
7249       if (code0 != REAL_TYPE || code1 != REAL_TYPE)
7250         {
7251           error ("unordered comparison on non-floating point argument");
7252           return error_mark_node;
7253         }
7254       common = 1;
7255       break;
7256
7257     default:
7258       break;
7259     }
7260
7261   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7262     return error_mark_node;
7263
7264   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7265        || code0 == VECTOR_TYPE)
7266       &&
7267       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7268        || code1 == VECTOR_TYPE))
7269     {
7270       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7271
7272       if (shorten || common || short_compare)
7273         result_type = common_type (type0, type1);
7274
7275       /* For certain operations (which identify themselves by shorten != 0)
7276          if both args were extended from the same smaller type,
7277          do the arithmetic in that type and then extend.
7278
7279          shorten !=0 and !=1 indicates a bitwise operation.
7280          For them, this optimization is safe only if
7281          both args are zero-extended or both are sign-extended.
7282          Otherwise, we might change the result.
7283          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7284          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7285
7286       if (shorten && none_complex)
7287         {
7288           int unsigned0, unsigned1;
7289           tree arg0 = get_narrower (op0, &unsigned0);
7290           tree arg1 = get_narrower (op1, &unsigned1);
7291           /* UNS is 1 if the operation to be done is an unsigned one.  */
7292           int uns = TYPE_UNSIGNED (result_type);
7293           tree type;
7294
7295           final_type = result_type;
7296
7297           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7298              but it *requires* conversion to FINAL_TYPE.  */
7299
7300           if ((TYPE_PRECISION (TREE_TYPE (op0))
7301                == TYPE_PRECISION (TREE_TYPE (arg0)))
7302               && TREE_TYPE (op0) != final_type)
7303             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7304           if ((TYPE_PRECISION (TREE_TYPE (op1))
7305                == TYPE_PRECISION (TREE_TYPE (arg1)))
7306               && TREE_TYPE (op1) != final_type)
7307             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7308
7309           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7310
7311           /* For bitwise operations, signedness of nominal type
7312              does not matter.  Consider only how operands were extended.  */
7313           if (shorten == -1)
7314             uns = unsigned0;
7315
7316           /* Note that in all three cases below we refrain from optimizing
7317              an unsigned operation on sign-extended args.
7318              That would not be valid.  */
7319
7320           /* Both args variable: if both extended in same way
7321              from same width, do it in that width.
7322              Do it unsigned if args were zero-extended.  */
7323           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7324                < TYPE_PRECISION (result_type))
7325               && (TYPE_PRECISION (TREE_TYPE (arg1))
7326                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7327               && unsigned0 == unsigned1
7328               && (unsigned0 || !uns))
7329             result_type
7330               = c_common_signed_or_unsigned_type
7331               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7332           else if (TREE_CODE (arg0) == INTEGER_CST
7333                    && (unsigned1 || !uns)
7334                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7335                        < TYPE_PRECISION (result_type))
7336                    && (type
7337                        = c_common_signed_or_unsigned_type (unsigned1,
7338                                                            TREE_TYPE (arg1)),
7339                        int_fits_type_p (arg0, type)))
7340             result_type = type;
7341           else if (TREE_CODE (arg1) == INTEGER_CST
7342                    && (unsigned0 || !uns)
7343                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7344                        < TYPE_PRECISION (result_type))
7345                    && (type
7346                        = c_common_signed_or_unsigned_type (unsigned0,
7347                                                            TREE_TYPE (arg0)),
7348                        int_fits_type_p (arg1, type)))
7349             result_type = type;
7350         }
7351
7352       /* Shifts can be shortened if shifting right.  */
7353
7354       if (short_shift)
7355         {
7356           int unsigned_arg;
7357           tree arg0 = get_narrower (op0, &unsigned_arg);
7358
7359           final_type = result_type;
7360
7361           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7362             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7363
7364           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7365               /* We can shorten only if the shift count is less than the
7366                  number of bits in the smaller type size.  */
7367               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7368               /* We cannot drop an unsigned shift after sign-extension.  */
7369               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7370             {
7371               /* Do an unsigned shift if the operand was zero-extended.  */
7372               result_type
7373                 = c_common_signed_or_unsigned_type (unsigned_arg,
7374                                                     TREE_TYPE (arg0));
7375               /* Convert value-to-be-shifted to that type.  */
7376               if (TREE_TYPE (op0) != result_type)
7377                 op0 = convert (result_type, op0);
7378               converted = 1;
7379             }
7380         }
7381
7382       /* Comparison operations are shortened too but differently.
7383          They identify themselves by setting short_compare = 1.  */
7384
7385       if (short_compare)
7386         {
7387           /* Don't write &op0, etc., because that would prevent op0
7388              from being kept in a register.
7389              Instead, make copies of the our local variables and
7390              pass the copies by reference, then copy them back afterward.  */
7391           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7392           enum tree_code xresultcode = resultcode;
7393           tree val
7394             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7395
7396           if (val != 0)
7397             return val;
7398
7399           op0 = xop0, op1 = xop1;
7400           converted = 1;
7401           resultcode = xresultcode;
7402
7403           if (warn_sign_compare && skip_evaluation == 0)
7404             {
7405               int op0_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7406               int op1_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7407               int unsignedp0, unsignedp1;
7408               tree primop0 = get_narrower (op0, &unsignedp0);
7409               tree primop1 = get_narrower (op1, &unsignedp1);
7410
7411               xop0 = orig_op0;
7412               xop1 = orig_op1;
7413               STRIP_TYPE_NOPS (xop0);
7414               STRIP_TYPE_NOPS (xop1);
7415
7416               /* Give warnings for comparisons between signed and unsigned
7417                  quantities that may fail.
7418
7419                  Do the checking based on the original operand trees, so that
7420                  casts will be considered, but default promotions won't be.
7421
7422                  Do not warn if the comparison is being done in a signed type,
7423                  since the signed type will only be chosen if it can represent
7424                  all the values of the unsigned type.  */
7425               if (! TYPE_UNSIGNED (result_type))
7426                 /* OK */;
7427               /* Do not warn if both operands are the same signedness.  */
7428               else if (op0_signed == op1_signed)
7429                 /* OK */;
7430               else
7431                 {
7432                   tree sop, uop;
7433
7434                   if (op0_signed)
7435                     sop = xop0, uop = xop1;
7436                   else
7437                     sop = xop1, uop = xop0;
7438
7439                   /* Do not warn if the signed quantity is an
7440                      unsuffixed integer literal (or some static
7441                      constant expression involving such literals or a
7442                      conditional expression involving such literals)
7443                      and it is non-negative.  */
7444                   if (tree_expr_nonnegative_p (sop))
7445                     /* OK */;
7446                   /* Do not warn if the comparison is an equality operation,
7447                      the unsigned quantity is an integral constant, and it
7448                      would fit in the result if the result were signed.  */
7449                   else if (TREE_CODE (uop) == INTEGER_CST
7450                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7451                            && int_fits_type_p
7452                            (uop, c_common_signed_type (result_type)))
7453                     /* OK */;
7454                   /* Do not warn if the unsigned quantity is an enumeration
7455                      constant and its maximum value would fit in the result
7456                      if the result were signed.  */
7457                   else if (TREE_CODE (uop) == INTEGER_CST
7458                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7459                            && int_fits_type_p
7460                            (TYPE_MAX_VALUE (TREE_TYPE(uop)),
7461                             c_common_signed_type (result_type)))
7462                     /* OK */;
7463                   else
7464                     warning ("comparison between signed and unsigned");
7465                 }
7466
7467               /* Warn if two unsigned values are being compared in a size
7468                  larger than their original size, and one (and only one) is the
7469                  result of a `~' operator.  This comparison will always fail.
7470
7471                  Also warn if one operand is a constant, and the constant
7472                  does not have all bits set that are set in the ~ operand
7473                  when it is extended.  */
7474
7475               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7476                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7477                 {
7478                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7479                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7480                                             &unsignedp0);
7481                   else
7482                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7483                                             &unsignedp1);
7484
7485                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7486                     {
7487                       tree primop;
7488                       HOST_WIDE_INT constant, mask;
7489                       int unsignedp, bits;
7490
7491                       if (host_integerp (primop0, 0))
7492                         {
7493                           primop = primop1;
7494                           unsignedp = unsignedp1;
7495                           constant = tree_low_cst (primop0, 0);
7496                         }
7497                       else
7498                         {
7499                           primop = primop0;
7500                           unsignedp = unsignedp0;
7501                           constant = tree_low_cst (primop1, 0);
7502                         }
7503
7504                       bits = TYPE_PRECISION (TREE_TYPE (primop));
7505                       if (bits < TYPE_PRECISION (result_type)
7506                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
7507                         {
7508                           mask = (~ (HOST_WIDE_INT) 0) << bits;
7509                           if ((mask & constant) != mask)
7510                             warning ("comparison of promoted ~unsigned with constant");
7511                         }
7512                     }
7513                   else if (unsignedp0 && unsignedp1
7514                            && (TYPE_PRECISION (TREE_TYPE (primop0))
7515                                < TYPE_PRECISION (result_type))
7516                            && (TYPE_PRECISION (TREE_TYPE (primop1))
7517                                < TYPE_PRECISION (result_type)))
7518                     warning ("comparison of promoted ~unsigned with unsigned");
7519                 }
7520             }
7521         }
7522     }
7523
7524   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7525      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7526      Then the expression will be built.
7527      It will be given type FINAL_TYPE if that is nonzero;
7528      otherwise, it will be given type RESULT_TYPE.  */
7529
7530   if (!result_type)
7531     {
7532       binary_op_error (code);
7533       return error_mark_node;
7534     }
7535
7536   if (! converted)
7537     {
7538       if (TREE_TYPE (op0) != result_type)
7539         op0 = convert (result_type, op0);
7540       if (TREE_TYPE (op1) != result_type)
7541         op1 = convert (result_type, op1);
7542     }
7543
7544   if (build_type == NULL_TREE)
7545     build_type = result_type;
7546
7547   {
7548     tree result = build (resultcode, build_type, op0, op1);
7549
7550     /* Treat expressions in initializers specially as they can't trap.  */
7551     result = require_constant_value ? fold_initializer (result)
7552                                     : fold (result);
7553
7554     if (final_type != 0)
7555       result = convert (final_type, result);
7556     return result;
7557   }
7558 }
7559
7560 /* Build the result of __builtin_offsetof.  TYPE is the first argument to
7561    offsetof, i.e. a type.  LIST is a tree_list that encodes component and
7562    array references; PURPOSE is set for the former and VALUE is set for
7563    the later.  */
7564
7565 tree
7566 build_offsetof (tree type, tree list)
7567 {
7568   tree t;
7569
7570   /* Build "*(type *)0".  */
7571   t = convert (build_pointer_type (type), null_pointer_node);
7572   t = build_indirect_ref (t, "");
7573
7574   /* Build COMPONENT and ARRAY_REF expressions as needed.  */
7575   for (list = nreverse (list); list ; list = TREE_CHAIN (list))
7576     if (TREE_PURPOSE (list))
7577       t = build_component_ref (t, TREE_PURPOSE (list));
7578     else
7579       t = build_array_ref (t, TREE_VALUE (list));
7580
7581   /* Finalize the offsetof expression.  For now all we need to do is take
7582      the address of the expression we created, and cast that to an integer
7583      type; this mirrors the traditional macro implementation of offsetof.  */
7584   t = build_unary_op (ADDR_EXPR, t, 0);
7585   return convert (size_type_node, t);
7586 }