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 build2 (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 build2 (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 = build3 (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 = build4 (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 build2 (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 = build3 (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                   unsigned 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 (build2 (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 build2 (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 = build2 (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 (build2 (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 (build3 (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 build2 (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 = build2 (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 = (char *) 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 = (char *) 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 = (char *) 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 = (char *) 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       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
3759                                   spelling_size);                       \
3760       RESTORE_SPELLING_DEPTH (depth);                                   \
3761     }                                                                   \
3762                                                                         \
3763   spelling->kind = (KIND);                                              \
3764   spelling->MEMBER = (VALUE);                                           \
3765   spelling++;                                                           \
3766 }
3767
3768 /* Push STRING on the stack.  Printed literally.  */
3769
3770 static void
3771 push_string (const char *string)
3772 {
3773   PUSH_SPELLING (SPELLING_STRING, string, u.s);
3774 }
3775
3776 /* Push a member name on the stack.  Printed as '.' STRING.  */
3777
3778 static void
3779 push_member_name (tree decl)
3780 {
3781   const char *const string
3782     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
3783   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
3784 }
3785
3786 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
3787
3788 static void
3789 push_array_bounds (int bounds)
3790 {
3791   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
3792 }
3793
3794 /* Compute the maximum size in bytes of the printed spelling.  */
3795
3796 static int
3797 spelling_length (void)
3798 {
3799   int size = 0;
3800   struct spelling *p;
3801
3802   for (p = spelling_base; p < spelling; p++)
3803     {
3804       if (p->kind == SPELLING_BOUNDS)
3805         size += 25;
3806       else
3807         size += strlen (p->u.s) + 1;
3808     }
3809
3810   return size;
3811 }
3812
3813 /* Print the spelling to BUFFER and return it.  */
3814
3815 static char *
3816 print_spelling (char *buffer)
3817 {
3818   char *d = buffer;
3819   struct spelling *p;
3820
3821   for (p = spelling_base; p < spelling; p++)
3822     if (p->kind == SPELLING_BOUNDS)
3823       {
3824         sprintf (d, "[%d]", p->u.i);
3825         d += strlen (d);
3826       }
3827     else
3828       {
3829         const char *s;
3830         if (p->kind == SPELLING_MEMBER)
3831           *d++ = '.';
3832         for (s = p->u.s; (*d = *s++); d++)
3833           ;
3834       }
3835   *d++ = '\0';
3836   return buffer;
3837 }
3838
3839 /* Issue an error message for a bad initializer component.
3840    MSGID identifies the message.
3841    The component name is taken from the spelling stack.  */
3842
3843 void
3844 error_init (const char *msgid)
3845 {
3846   char *ofwhat;
3847
3848   error ("%s", _(msgid));
3849   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3850   if (*ofwhat)
3851     error ("(near initialization for `%s')", ofwhat);
3852 }
3853
3854 /* Issue a pedantic warning for a bad initializer component.
3855    MSGID identifies the message.
3856    The component name is taken from the spelling stack.  */
3857
3858 void
3859 pedwarn_init (const char *msgid)
3860 {
3861   char *ofwhat;
3862
3863   pedwarn ("%s", _(msgid));
3864   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3865   if (*ofwhat)
3866     pedwarn ("(near initialization for `%s')", ofwhat);
3867 }
3868
3869 /* Issue a warning for a bad initializer component.
3870    MSGID identifies the message.
3871    The component name is taken from the spelling stack.  */
3872
3873 static void
3874 warning_init (const char *msgid)
3875 {
3876   char *ofwhat;
3877
3878   warning ("%s", _(msgid));
3879   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3880   if (*ofwhat)
3881     warning ("(near initialization for `%s')", ofwhat);
3882 }
3883 \f
3884 /* If TYPE is an array type and EXPR is a parenthesized string
3885    constant, warn if pedantic that EXPR is being used to initialize an
3886    object of type TYPE.  */
3887
3888 void
3889 maybe_warn_string_init (tree type, struct c_expr expr)
3890 {
3891   if (pedantic
3892       && TREE_CODE (type) == ARRAY_TYPE
3893       && TREE_CODE (expr.value) == STRING_CST
3894       && expr.original_code != STRING_CST)
3895     pedwarn_init ("array initialized from parenthesized string constant");
3896 }
3897
3898 /* Digest the parser output INIT as an initializer for type TYPE.
3899    Return a C expression of type TYPE to represent the initial value.
3900
3901    If INIT is a string constant, STRICT_STRING is true if it is
3902    unparenthesized or we should not warn here for it being parenthesized.
3903    For other types of INIT, STRICT_STRING is not used.
3904
3905    REQUIRE_CONSTANT requests an error if non-constant initializers or
3906    elements are seen.  */
3907
3908 static tree
3909 digest_init (tree type, tree init, bool strict_string, int require_constant)
3910 {
3911   enum tree_code code = TREE_CODE (type);
3912   tree inside_init = init;
3913
3914   if (type == error_mark_node
3915       || init == error_mark_node
3916       || TREE_TYPE (init) == error_mark_node)
3917     return error_mark_node;
3918
3919   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3920   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3921      whose value is 0 to count as a null pointer constant.  */
3922   if (TREE_CODE (init) == NON_LVALUE_EXPR)
3923     inside_init = TREE_OPERAND (init, 0);
3924
3925   inside_init = fold (inside_init);
3926
3927   /* Initialization of an array of chars from a string constant
3928      optionally enclosed in braces.  */
3929
3930   if (code == ARRAY_TYPE && inside_init
3931       && TREE_CODE (inside_init) == STRING_CST)
3932     {
3933       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
3934       /* Note that an array could be both an array of character type
3935          and an array of wchar_t if wchar_t is signed char or unsigned
3936          char.  */
3937       bool char_array = (typ1 == char_type_node
3938                          || typ1 == signed_char_type_node
3939                          || typ1 == unsigned_char_type_node);
3940       bool wchar_array = !!comptypes (typ1, wchar_type_node);
3941       if (char_array || wchar_array)
3942         {
3943           struct c_expr expr;
3944           bool char_string;
3945           expr.value = inside_init;
3946           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
3947           maybe_warn_string_init (type, expr);
3948
3949           char_string
3950             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3951                == char_type_node);
3952
3953           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
3954                          TYPE_MAIN_VARIANT (type)))
3955             return inside_init;
3956
3957           if (!wchar_array && !char_string)
3958             {
3959               error_init ("char-array initialized from wide string");
3960               return error_mark_node;
3961             }
3962           if (char_string && !char_array)
3963             {
3964               error_init ("wchar_t-array initialized from non-wide string");
3965               return error_mark_node;
3966             }
3967
3968           TREE_TYPE (inside_init) = type;
3969           if (TYPE_DOMAIN (type) != 0
3970               && TYPE_SIZE (type) != 0
3971               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
3972               /* Subtract 1 (or sizeof (wchar_t))
3973                  because it's ok to ignore the terminating null char
3974                  that is counted in the length of the constant.  */
3975               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
3976                                        TREE_STRING_LENGTH (inside_init)
3977                                        - ((TYPE_PRECISION (typ1)
3978                                            != TYPE_PRECISION (char_type_node))
3979                                           ? (TYPE_PRECISION (wchar_type_node)
3980                                              / BITS_PER_UNIT)
3981                                           : 1)))
3982             pedwarn_init ("initializer-string for array of chars is too long");
3983
3984           return inside_init;
3985         }
3986       else if (INTEGRAL_TYPE_P (typ1))
3987         {
3988           error_init ("array of inappropriate type initialized "
3989                       "from string constant");
3990           return error_mark_node;
3991         }
3992     }
3993
3994   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
3995      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
3996      below and handle as a constructor.  */
3997     if (code == VECTOR_TYPE
3998         && vector_types_convertible_p (TREE_TYPE (inside_init), type)
3999         && TREE_CONSTANT (inside_init))
4000       {
4001         if (TREE_CODE (inside_init) == VECTOR_CST
4002             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4003                           TYPE_MAIN_VARIANT (type)))
4004           return inside_init;
4005         else
4006           return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4007       }
4008
4009   /* Any type can be initialized
4010      from an expression of the same type, optionally with braces.  */
4011
4012   if (inside_init && TREE_TYPE (inside_init) != 0
4013       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4014                      TYPE_MAIN_VARIANT (type))
4015           || (code == ARRAY_TYPE
4016               && comptypes (TREE_TYPE (inside_init), type))
4017           || (code == VECTOR_TYPE
4018               && comptypes (TREE_TYPE (inside_init), type))
4019           || (code == POINTER_TYPE
4020               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4021               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4022                             TREE_TYPE (type)))
4023           || (code == POINTER_TYPE
4024               && TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE
4025               && comptypes (TREE_TYPE (inside_init),
4026                             TREE_TYPE (type)))))
4027     {
4028       if (code == POINTER_TYPE)
4029         {
4030           inside_init = default_function_array_conversion (inside_init);
4031
4032           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4033             {
4034               error_init ("invalid use of non-lvalue array");
4035               return error_mark_node;
4036             }
4037          }
4038
4039       if (code == VECTOR_TYPE)
4040         /* Although the types are compatible, we may require a
4041            conversion.  */
4042         inside_init = convert (type, inside_init);
4043
4044       if (require_constant && !flag_isoc99
4045           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4046         {
4047           /* As an extension, allow initializing objects with static storage
4048              duration with compound literals (which are then treated just as
4049              the brace enclosed list they contain).  */
4050           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4051           inside_init = DECL_INITIAL (decl);
4052         }
4053
4054       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4055           && TREE_CODE (inside_init) != CONSTRUCTOR)
4056         {
4057           error_init ("array initialized from non-constant array expression");
4058           return error_mark_node;
4059         }
4060
4061       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4062         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4063
4064       /* Compound expressions can only occur here if -pedantic or
4065          -pedantic-errors is specified.  In the later case, we always want
4066          an error.  In the former case, we simply want a warning.  */
4067       if (require_constant && pedantic
4068           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4069         {
4070           inside_init
4071             = valid_compound_expr_initializer (inside_init,
4072                                                TREE_TYPE (inside_init));
4073           if (inside_init == error_mark_node)
4074             error_init ("initializer element is not constant");
4075           else
4076             pedwarn_init ("initializer element is not constant");
4077           if (flag_pedantic_errors)
4078             inside_init = error_mark_node;
4079         }
4080       else if (require_constant
4081                && (!TREE_CONSTANT (inside_init)
4082                    /* This test catches things like `7 / 0' which
4083                       result in an expression for which TREE_CONSTANT
4084                       is true, but which is not actually something
4085                       that is a legal constant.  We really should not
4086                       be using this function, because it is a part of
4087                       the back-end.  Instead, the expression should
4088                       already have been turned into ERROR_MARK_NODE.  */
4089                    || !initializer_constant_valid_p (inside_init,
4090                                                      TREE_TYPE (inside_init))))
4091         {
4092           error_init ("initializer element is not constant");
4093           inside_init = error_mark_node;
4094         }
4095
4096       return inside_init;
4097     }
4098
4099   /* Handle scalar types, including conversions.  */
4100
4101   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4102       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4103       || code == VECTOR_TYPE)
4104     {
4105       /* Note that convert_for_assignment calls default_conversion
4106          for arrays and functions.  We must not call it in the
4107          case where inside_init is a null pointer constant.  */
4108       inside_init
4109         = convert_for_assignment (type, init, _("initialization"),
4110                                   NULL_TREE, NULL_TREE, 0);
4111
4112       if (require_constant && ! TREE_CONSTANT (inside_init))
4113         {
4114           error_init ("initializer element is not constant");
4115           inside_init = error_mark_node;
4116         }
4117       else if (require_constant
4118                && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
4119         {
4120           error_init ("initializer element is not computable at load time");
4121           inside_init = error_mark_node;
4122         }
4123
4124       return inside_init;
4125     }
4126
4127   /* Come here only for records and arrays.  */
4128
4129   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4130     {
4131       error_init ("variable-sized object may not be initialized");
4132       return error_mark_node;
4133     }
4134
4135   error_init ("invalid initializer");
4136   return error_mark_node;
4137 }
4138 \f
4139 /* Handle initializers that use braces.  */
4140
4141 /* Type of object we are accumulating a constructor for.
4142    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4143 static tree constructor_type;
4144
4145 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4146    left to fill.  */
4147 static tree constructor_fields;
4148
4149 /* For an ARRAY_TYPE, this is the specified index
4150    at which to store the next element we get.  */
4151 static tree constructor_index;
4152
4153 /* For an ARRAY_TYPE, this is the maximum index.  */
4154 static tree constructor_max_index;
4155
4156 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4157 static tree constructor_unfilled_fields;
4158
4159 /* For an ARRAY_TYPE, this is the index of the first element
4160    not yet written out.  */
4161 static tree constructor_unfilled_index;
4162
4163 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4164    This is so we can generate gaps between fields, when appropriate.  */
4165 static tree constructor_bit_index;
4166
4167 /* If we are saving up the elements rather than allocating them,
4168    this is the list of elements so far (in reverse order,
4169    most recent first).  */
4170 static tree constructor_elements;
4171
4172 /* 1 if constructor should be incrementally stored into a constructor chain,
4173    0 if all the elements should be kept in AVL tree.  */
4174 static int constructor_incremental;
4175
4176 /* 1 if so far this constructor's elements are all compile-time constants.  */
4177 static int constructor_constant;
4178
4179 /* 1 if so far this constructor's elements are all valid address constants.  */
4180 static int constructor_simple;
4181
4182 /* 1 if this constructor is erroneous so far.  */
4183 static int constructor_erroneous;
4184
4185 /* Structure for managing pending initializer elements, organized as an
4186    AVL tree.  */
4187
4188 struct init_node
4189 {
4190   struct init_node *left, *right;
4191   struct init_node *parent;
4192   int balance;
4193   tree purpose;
4194   tree value;
4195 };
4196
4197 /* Tree of pending elements at this constructor level.
4198    These are elements encountered out of order
4199    which belong at places we haven't reached yet in actually
4200    writing the output.
4201    Will never hold tree nodes across GC runs.  */
4202 static struct init_node *constructor_pending_elts;
4203
4204 /* The SPELLING_DEPTH of this constructor.  */
4205 static int constructor_depth;
4206
4207 /* 0 if implicitly pushing constructor levels is allowed.  */
4208 int constructor_no_implicit = 0; /* 0 for C; 1 for some other languages.  */
4209
4210 /* DECL node for which an initializer is being read.
4211    0 means we are reading a constructor expression
4212    such as (struct foo) {...}.  */
4213 static tree constructor_decl;
4214
4215 /* start_init saves the ASMSPEC arg here for really_start_incremental_init.  */
4216 static const char *constructor_asmspec;
4217
4218 /* Nonzero if this is an initializer for a top-level decl.  */
4219 static int constructor_top_level;
4220
4221 /* Nonzero if there were any member designators in this initializer.  */
4222 static int constructor_designated;
4223
4224 /* Nesting depth of designator list.  */
4225 static int designator_depth;
4226
4227 /* Nonzero if there were diagnosed errors in this designator list.  */
4228 static int designator_errorneous;
4229
4230 \f
4231 /* This stack has a level for each implicit or explicit level of
4232    structuring in the initializer, including the outermost one.  It
4233    saves the values of most of the variables above.  */
4234
4235 struct constructor_range_stack;
4236
4237 struct constructor_stack
4238 {
4239   struct constructor_stack *next;
4240   tree type;
4241   tree fields;
4242   tree index;
4243   tree max_index;
4244   tree unfilled_index;
4245   tree unfilled_fields;
4246   tree bit_index;
4247   tree elements;
4248   struct init_node *pending_elts;
4249   int offset;
4250   int depth;
4251   /* If value nonzero, this value should replace the entire
4252      constructor at this level.  */
4253   struct c_expr replacement_value;
4254   struct constructor_range_stack *range_stack;
4255   char constant;
4256   char simple;
4257   char implicit;
4258   char erroneous;
4259   char outer;
4260   char incremental;
4261   char designated;
4262 };
4263
4264 struct constructor_stack *constructor_stack;
4265
4266 /* This stack represents designators from some range designator up to
4267    the last designator in the list.  */
4268
4269 struct constructor_range_stack
4270 {
4271   struct constructor_range_stack *next, *prev;
4272   struct constructor_stack *stack;
4273   tree range_start;
4274   tree index;
4275   tree range_end;
4276   tree fields;
4277 };
4278
4279 struct constructor_range_stack *constructor_range_stack;
4280
4281 /* This stack records separate initializers that are nested.
4282    Nested initializers can't happen in ANSI C, but GNU C allows them
4283    in cases like { ... (struct foo) { ... } ... }.  */
4284
4285 struct initializer_stack
4286 {
4287   struct initializer_stack *next;
4288   tree decl;
4289   const char *asmspec;
4290   struct constructor_stack *constructor_stack;
4291   struct constructor_range_stack *constructor_range_stack;
4292   tree elements;
4293   struct spelling *spelling;
4294   struct spelling *spelling_base;
4295   int spelling_size;
4296   char top_level;
4297   char require_constant_value;
4298   char require_constant_elements;
4299 };
4300
4301 struct initializer_stack *initializer_stack;
4302 \f
4303 /* Prepare to parse and output the initializer for variable DECL.  */
4304
4305 void
4306 start_init (tree decl, tree asmspec_tree, int top_level)
4307 {
4308   const char *locus;
4309   struct initializer_stack *p = XNEW (struct initializer_stack);
4310   const char *asmspec = 0;
4311
4312   if (asmspec_tree)
4313     asmspec = TREE_STRING_POINTER (asmspec_tree);
4314
4315   p->decl = constructor_decl;
4316   p->asmspec = constructor_asmspec;
4317   p->require_constant_value = require_constant_value;
4318   p->require_constant_elements = require_constant_elements;
4319   p->constructor_stack = constructor_stack;
4320   p->constructor_range_stack = constructor_range_stack;
4321   p->elements = constructor_elements;
4322   p->spelling = spelling;
4323   p->spelling_base = spelling_base;
4324   p->spelling_size = spelling_size;
4325   p->top_level = constructor_top_level;
4326   p->next = initializer_stack;
4327   initializer_stack = p;
4328
4329   constructor_decl = decl;
4330   constructor_asmspec = asmspec;
4331   constructor_designated = 0;
4332   constructor_top_level = top_level;
4333
4334   if (decl != 0)
4335     {
4336       require_constant_value = TREE_STATIC (decl);
4337       require_constant_elements
4338         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4339            /* For a scalar, you can always use any value to initialize,
4340               even within braces.  */
4341            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4342                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4343                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4344                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4345       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4346     }
4347   else
4348     {
4349       require_constant_value = 0;
4350       require_constant_elements = 0;
4351       locus = "(anonymous)";
4352     }
4353
4354   constructor_stack = 0;
4355   constructor_range_stack = 0;
4356
4357   missing_braces_mentioned = 0;
4358
4359   spelling_base = 0;
4360   spelling_size = 0;
4361   RESTORE_SPELLING_DEPTH (0);
4362
4363   if (locus)
4364     push_string (locus);
4365 }
4366
4367 void
4368 finish_init (void)
4369 {
4370   struct initializer_stack *p = initializer_stack;
4371
4372   /* Free the whole constructor stack of this initializer.  */
4373   while (constructor_stack)
4374     {
4375       struct constructor_stack *q = constructor_stack;
4376       constructor_stack = q->next;
4377       free (q);
4378     }
4379
4380   if (constructor_range_stack)
4381     abort ();
4382
4383   /* Pop back to the data of the outer initializer (if any).  */
4384   free (spelling_base);
4385
4386   constructor_decl = p->decl;
4387   constructor_asmspec = p->asmspec;
4388   require_constant_value = p->require_constant_value;
4389   require_constant_elements = p->require_constant_elements;
4390   constructor_stack = p->constructor_stack;
4391   constructor_range_stack = p->constructor_range_stack;
4392   constructor_elements = p->elements;
4393   spelling = p->spelling;
4394   spelling_base = p->spelling_base;
4395   spelling_size = p->spelling_size;
4396   constructor_top_level = p->top_level;
4397   initializer_stack = p->next;
4398   free (p);
4399 }
4400 \f
4401 /* Call here when we see the initializer is surrounded by braces.
4402    This is instead of a call to push_init_level;
4403    it is matched by a call to pop_init_level.
4404
4405    TYPE is the type to initialize, for a constructor expression.
4406    For an initializer for a decl, TYPE is zero.  */
4407
4408 void
4409 really_start_incremental_init (tree type)
4410 {
4411   struct constructor_stack *p = XNEW (struct constructor_stack);
4412
4413   if (type == 0)
4414     type = TREE_TYPE (constructor_decl);
4415
4416   if (targetm.vector_opaque_p (type))
4417     error ("opaque vector types cannot be initialized");
4418
4419   p->type = constructor_type;
4420   p->fields = constructor_fields;
4421   p->index = constructor_index;
4422   p->max_index = constructor_max_index;
4423   p->unfilled_index = constructor_unfilled_index;
4424   p->unfilled_fields = constructor_unfilled_fields;
4425   p->bit_index = constructor_bit_index;
4426   p->elements = constructor_elements;
4427   p->constant = constructor_constant;
4428   p->simple = constructor_simple;
4429   p->erroneous = constructor_erroneous;
4430   p->pending_elts = constructor_pending_elts;
4431   p->depth = constructor_depth;
4432   p->replacement_value.value = 0;
4433   p->replacement_value.original_code = ERROR_MARK;
4434   p->implicit = 0;
4435   p->range_stack = 0;
4436   p->outer = 0;
4437   p->incremental = constructor_incremental;
4438   p->designated = constructor_designated;
4439   p->next = 0;
4440   constructor_stack = p;
4441
4442   constructor_constant = 1;
4443   constructor_simple = 1;
4444   constructor_depth = SPELLING_DEPTH ();
4445   constructor_elements = 0;
4446   constructor_pending_elts = 0;
4447   constructor_type = type;
4448   constructor_incremental = 1;
4449   constructor_designated = 0;
4450   designator_depth = 0;
4451   designator_errorneous = 0;
4452
4453   if (TREE_CODE (constructor_type) == RECORD_TYPE
4454       || TREE_CODE (constructor_type) == UNION_TYPE)
4455     {
4456       constructor_fields = TYPE_FIELDS (constructor_type);
4457       /* Skip any nameless bit fields at the beginning.  */
4458       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4459              && DECL_NAME (constructor_fields) == 0)
4460         constructor_fields = TREE_CHAIN (constructor_fields);
4461
4462       constructor_unfilled_fields = constructor_fields;
4463       constructor_bit_index = bitsize_zero_node;
4464     }
4465   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4466     {
4467       if (TYPE_DOMAIN (constructor_type))
4468         {
4469           constructor_max_index
4470             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4471
4472           /* Detect non-empty initializations of zero-length arrays.  */
4473           if (constructor_max_index == NULL_TREE
4474               && TYPE_SIZE (constructor_type))
4475             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4476
4477           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4478              to initialize VLAs will cause a proper error; avoid tree
4479              checking errors as well by setting a safe value.  */
4480           if (constructor_max_index
4481               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4482             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4483
4484           constructor_index
4485             = convert (bitsizetype,
4486                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4487         }
4488       else
4489         constructor_index = bitsize_zero_node;
4490
4491       constructor_unfilled_index = constructor_index;
4492     }
4493   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4494     {
4495       /* Vectors are like simple fixed-size arrays.  */
4496       constructor_max_index =
4497         build_int_cst (NULL_TREE,
4498                        TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4499       constructor_index = convert (bitsizetype, bitsize_zero_node);
4500       constructor_unfilled_index = constructor_index;
4501     }
4502   else
4503     {
4504       /* Handle the case of int x = {5}; */
4505       constructor_fields = constructor_type;
4506       constructor_unfilled_fields = constructor_type;
4507     }
4508 }
4509 \f
4510 /* Push down into a subobject, for initialization.
4511    If this is for an explicit set of braces, IMPLICIT is 0.
4512    If it is because the next element belongs at a lower level,
4513    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4514
4515 void
4516 push_init_level (int implicit)
4517 {
4518   struct constructor_stack *p;
4519   tree value = NULL_TREE;
4520
4521   /* If we've exhausted any levels that didn't have braces,
4522      pop them now.  */
4523   while (constructor_stack->implicit)
4524     {
4525       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4526            || TREE_CODE (constructor_type) == UNION_TYPE)
4527           && constructor_fields == 0)
4528         process_init_element (pop_init_level (1));
4529       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4530                && constructor_max_index
4531                && tree_int_cst_lt (constructor_max_index, constructor_index))
4532         process_init_element (pop_init_level (1));
4533       else
4534         break;
4535     }
4536
4537   /* Unless this is an explicit brace, we need to preserve previous
4538      content if any.  */
4539   if (implicit)
4540     {
4541       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4542            || TREE_CODE (constructor_type) == UNION_TYPE)
4543           && constructor_fields)
4544         value = find_init_member (constructor_fields);
4545       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4546         value = find_init_member (constructor_index);
4547     }
4548
4549   p = XNEW (struct constructor_stack);
4550   p->type = constructor_type;
4551   p->fields = constructor_fields;
4552   p->index = constructor_index;
4553   p->max_index = constructor_max_index;
4554   p->unfilled_index = constructor_unfilled_index;
4555   p->unfilled_fields = constructor_unfilled_fields;
4556   p->bit_index = constructor_bit_index;
4557   p->elements = constructor_elements;
4558   p->constant = constructor_constant;
4559   p->simple = constructor_simple;
4560   p->erroneous = constructor_erroneous;
4561   p->pending_elts = constructor_pending_elts;
4562   p->depth = constructor_depth;
4563   p->replacement_value.value = 0;
4564   p->replacement_value.original_code = ERROR_MARK;
4565   p->implicit = implicit;
4566   p->outer = 0;
4567   p->incremental = constructor_incremental;
4568   p->designated = constructor_designated;
4569   p->next = constructor_stack;
4570   p->range_stack = 0;
4571   constructor_stack = p;
4572
4573   constructor_constant = 1;
4574   constructor_simple = 1;
4575   constructor_depth = SPELLING_DEPTH ();
4576   constructor_elements = 0;
4577   constructor_incremental = 1;
4578   constructor_designated = 0;
4579   constructor_pending_elts = 0;
4580   if (!implicit)
4581     {
4582       p->range_stack = constructor_range_stack;
4583       constructor_range_stack = 0;
4584       designator_depth = 0;
4585       designator_errorneous = 0;
4586     }
4587
4588   /* Don't die if an entire brace-pair level is superfluous
4589      in the containing level.  */
4590   if (constructor_type == 0)
4591     ;
4592   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4593            || TREE_CODE (constructor_type) == UNION_TYPE)
4594     {
4595       /* Don't die if there are extra init elts at the end.  */
4596       if (constructor_fields == 0)
4597         constructor_type = 0;
4598       else
4599         {
4600           constructor_type = TREE_TYPE (constructor_fields);
4601           push_member_name (constructor_fields);
4602           constructor_depth++;
4603         }
4604     }
4605   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4606     {
4607       constructor_type = TREE_TYPE (constructor_type);
4608       push_array_bounds (tree_low_cst (constructor_index, 0));
4609       constructor_depth++;
4610     }
4611
4612   if (constructor_type == 0)
4613     {
4614       error_init ("extra brace group at end of initializer");
4615       constructor_fields = 0;
4616       constructor_unfilled_fields = 0;
4617       return;
4618     }
4619
4620   if (value && TREE_CODE (value) == CONSTRUCTOR)
4621     {
4622       constructor_constant = TREE_CONSTANT (value);
4623       constructor_simple = TREE_STATIC (value);
4624       constructor_elements = CONSTRUCTOR_ELTS (value);
4625       if (constructor_elements
4626           && (TREE_CODE (constructor_type) == RECORD_TYPE
4627               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4628         set_nonincremental_init ();
4629     }
4630
4631   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4632     {
4633       missing_braces_mentioned = 1;
4634       warning_init ("missing braces around initializer");
4635     }
4636
4637   if (TREE_CODE (constructor_type) == RECORD_TYPE
4638            || TREE_CODE (constructor_type) == UNION_TYPE)
4639     {
4640       constructor_fields = TYPE_FIELDS (constructor_type);
4641       /* Skip any nameless bit fields at the beginning.  */
4642       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4643              && DECL_NAME (constructor_fields) == 0)
4644         constructor_fields = TREE_CHAIN (constructor_fields);
4645
4646       constructor_unfilled_fields = constructor_fields;
4647       constructor_bit_index = bitsize_zero_node;
4648     }
4649   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4650     {
4651       /* Vectors are like simple fixed-size arrays.  */
4652       constructor_max_index =
4653         build_int_cst (NULL_TREE,
4654                        TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4655       constructor_index = convert (bitsizetype, integer_zero_node);
4656       constructor_unfilled_index = constructor_index;
4657     }
4658   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4659     {
4660       if (TYPE_DOMAIN (constructor_type))
4661         {
4662           constructor_max_index
4663             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4664
4665           /* Detect non-empty initializations of zero-length arrays.  */
4666           if (constructor_max_index == NULL_TREE
4667               && TYPE_SIZE (constructor_type))
4668             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4669
4670           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4671              to initialize VLAs will cause a proper error; avoid tree
4672              checking errors as well by setting a safe value.  */
4673           if (constructor_max_index
4674               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4675             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4676
4677           constructor_index
4678             = convert (bitsizetype,
4679                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4680         }
4681       else
4682         constructor_index = bitsize_zero_node;
4683
4684       constructor_unfilled_index = constructor_index;
4685       if (value && TREE_CODE (value) == STRING_CST)
4686         {
4687           /* We need to split the char/wchar array into individual
4688              characters, so that we don't have to special case it
4689              everywhere.  */
4690           set_nonincremental_init_from_string (value);
4691         }
4692     }
4693   else
4694     {
4695       warning_init ("braces around scalar initializer");
4696       constructor_fields = constructor_type;
4697       constructor_unfilled_fields = constructor_type;
4698     }
4699 }
4700
4701 /* At the end of an implicit or explicit brace level,
4702    finish up that level of constructor.  If a single expression
4703    with redundant braces initialized that level, return the
4704    c_expr structure for that expression.  Otherwise, the original_code
4705    element is set to ERROR_MARK.
4706    If we were outputting the elements as they are read, return 0 as the value
4707    from inner levels (process_init_element ignores that),
4708    but return error_mark_node as the value from the outermost level
4709    (that's what we want to put in DECL_INITIAL).
4710    Otherwise, return a CONSTRUCTOR expression as the value.  */
4711
4712 struct c_expr
4713 pop_init_level (int implicit)
4714 {
4715   struct constructor_stack *p;
4716   struct c_expr ret;
4717   ret.value = 0;
4718   ret.original_code = ERROR_MARK;
4719
4720   if (implicit == 0)
4721     {
4722       /* When we come to an explicit close brace,
4723          pop any inner levels that didn't have explicit braces.  */
4724       while (constructor_stack->implicit)
4725         process_init_element (pop_init_level (1));
4726
4727       if (constructor_range_stack)
4728         abort ();
4729     }
4730
4731   /* Now output all pending elements.  */
4732   constructor_incremental = 1;
4733   output_pending_init_elements (1);
4734
4735   p = constructor_stack;
4736
4737   /* Error for initializing a flexible array member, or a zero-length
4738      array member in an inappropriate context.  */
4739   if (constructor_type && constructor_fields
4740       && TREE_CODE (constructor_type) == ARRAY_TYPE
4741       && TYPE_DOMAIN (constructor_type)
4742       && ! TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
4743     {
4744       /* Silently discard empty initializations.  The parser will
4745          already have pedwarned for empty brackets.  */
4746       if (integer_zerop (constructor_unfilled_index))
4747         constructor_type = NULL_TREE;
4748       else if (! TYPE_SIZE (constructor_type))
4749         {
4750           if (constructor_depth > 2)
4751             error_init ("initialization of flexible array member in a nested context");
4752           else if (pedantic)
4753             pedwarn_init ("initialization of a flexible array member");
4754
4755           /* We have already issued an error message for the existence
4756              of a flexible array member not at the end of the structure.
4757              Discard the initializer so that we do not abort later.  */
4758           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
4759             constructor_type = NULL_TREE;
4760         }
4761       else
4762         /* Zero-length arrays are no longer special, so we should no longer
4763            get here.  */
4764         abort ();
4765     }
4766
4767   /* Warn when some struct elements are implicitly initialized to zero.  */
4768   if (warn_missing_field_initializers
4769       && constructor_type
4770       && TREE_CODE (constructor_type) == RECORD_TYPE
4771       && constructor_unfilled_fields)
4772     {
4773         /* Do not warn for flexible array members or zero-length arrays.  */
4774         while (constructor_unfilled_fields
4775                && (! DECL_SIZE (constructor_unfilled_fields)
4776                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
4777           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
4778
4779         /* Do not warn if this level of the initializer uses member
4780            designators; it is likely to be deliberate.  */
4781         if (constructor_unfilled_fields && !constructor_designated)
4782           {
4783             push_member_name (constructor_unfilled_fields);
4784             warning_init ("missing initializer");
4785             RESTORE_SPELLING_DEPTH (constructor_depth);
4786           }
4787     }
4788
4789   /* Pad out the end of the structure.  */
4790   if (p->replacement_value.value)
4791     /* If this closes a superfluous brace pair,
4792        just pass out the element between them.  */
4793     ret = p->replacement_value;
4794   else if (constructor_type == 0)
4795     ;
4796   else if (TREE_CODE (constructor_type) != RECORD_TYPE
4797            && TREE_CODE (constructor_type) != UNION_TYPE
4798            && TREE_CODE (constructor_type) != ARRAY_TYPE
4799            && TREE_CODE (constructor_type) != VECTOR_TYPE)
4800     {
4801       /* A nonincremental scalar initializer--just return
4802          the element, after verifying there is just one.  */
4803       if (constructor_elements == 0)
4804         {
4805           if (!constructor_erroneous)
4806             error_init ("empty scalar initializer");
4807           ret.value = error_mark_node;
4808         }
4809       else if (TREE_CHAIN (constructor_elements) != 0)
4810         {
4811           error_init ("extra elements in scalar initializer");
4812           ret.value = TREE_VALUE (constructor_elements);
4813         }
4814       else
4815         ret.value = TREE_VALUE (constructor_elements);
4816     }
4817   else
4818     {
4819       if (constructor_erroneous)
4820         ret.value = error_mark_node;
4821       else
4822         {
4823           ret.value = build_constructor (constructor_type,
4824                                          nreverse (constructor_elements));
4825           if (constructor_constant)
4826             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
4827           if (constructor_constant && constructor_simple)
4828             TREE_STATIC (ret.value) = 1;
4829         }
4830     }
4831
4832   constructor_type = p->type;
4833   constructor_fields = p->fields;
4834   constructor_index = p->index;
4835   constructor_max_index = p->max_index;
4836   constructor_unfilled_index = p->unfilled_index;
4837   constructor_unfilled_fields = p->unfilled_fields;
4838   constructor_bit_index = p->bit_index;
4839   constructor_elements = p->elements;
4840   constructor_constant = p->constant;
4841   constructor_simple = p->simple;
4842   constructor_erroneous = p->erroneous;
4843   constructor_incremental = p->incremental;
4844   constructor_designated = p->designated;
4845   constructor_pending_elts = p->pending_elts;
4846   constructor_depth = p->depth;
4847   if (!p->implicit)
4848     constructor_range_stack = p->range_stack;
4849   RESTORE_SPELLING_DEPTH (constructor_depth);
4850
4851   constructor_stack = p->next;
4852   free (p);
4853
4854   if (ret.value == 0)
4855     {
4856       if (constructor_stack == 0)
4857         {
4858           ret.value = error_mark_node;
4859           return ret;
4860         }
4861       return ret;
4862     }
4863   return ret;
4864 }
4865
4866 /* Common handling for both array range and field name designators.
4867    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
4868
4869 static int
4870 set_designator (int array)
4871 {
4872   tree subtype;
4873   enum tree_code subcode;
4874
4875   /* Don't die if an entire brace-pair level is superfluous
4876      in the containing level.  */
4877   if (constructor_type == 0)
4878     return 1;
4879
4880   /* If there were errors in this designator list already, bail out silently.  */
4881   if (designator_errorneous)
4882     return 1;
4883
4884   if (!designator_depth)
4885     {
4886       if (constructor_range_stack)
4887         abort ();
4888
4889       /* Designator list starts at the level of closest explicit
4890          braces.  */
4891       while (constructor_stack->implicit)
4892         process_init_element (pop_init_level (1));
4893       constructor_designated = 1;
4894       return 0;
4895     }
4896
4897   if (constructor_no_implicit)
4898     {
4899       error_init ("initialization designators may not nest");
4900       return 1;
4901     }
4902
4903   if (TREE_CODE (constructor_type) == RECORD_TYPE
4904       || TREE_CODE (constructor_type) == UNION_TYPE)
4905     {
4906       subtype = TREE_TYPE (constructor_fields);
4907       if (subtype != error_mark_node)
4908         subtype = TYPE_MAIN_VARIANT (subtype);
4909     }
4910   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4911     {
4912       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
4913     }
4914   else
4915     abort ();
4916
4917   subcode = TREE_CODE (subtype);
4918   if (array && subcode != ARRAY_TYPE)
4919     {
4920       error_init ("array index in non-array initializer");
4921       return 1;
4922     }
4923   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
4924     {
4925       error_init ("field name not in record or union initializer");
4926       return 1;
4927     }
4928
4929   constructor_designated = 1;
4930   push_init_level (2);
4931   return 0;
4932 }
4933
4934 /* If there are range designators in designator list, push a new designator
4935    to constructor_range_stack.  RANGE_END is end of such stack range or
4936    NULL_TREE if there is no range designator at this level.  */
4937
4938 static void
4939 push_range_stack (tree range_end)
4940 {
4941   struct constructor_range_stack *p;
4942
4943   p = GGC_NEW (struct constructor_range_stack);
4944   p->prev = constructor_range_stack;
4945   p->next = 0;
4946   p->fields = constructor_fields;
4947   p->range_start = constructor_index;
4948   p->index = constructor_index;
4949   p->stack = constructor_stack;
4950   p->range_end = range_end;
4951   if (constructor_range_stack)
4952     constructor_range_stack->next = p;
4953   constructor_range_stack = p;
4954 }
4955
4956 /* Within an array initializer, specify the next index to be initialized.
4957    FIRST is that index.  If LAST is nonzero, then initialize a range
4958    of indices, running from FIRST through LAST.  */
4959
4960 void
4961 set_init_index (tree first, tree last)
4962 {
4963   if (set_designator (1))
4964     return;
4965
4966   designator_errorneous = 1;
4967
4968   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
4969       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
4970     {
4971       error_init ("array index in initializer not of integer type");
4972       return;
4973     }
4974
4975   while ((TREE_CODE (first) == NOP_EXPR
4976           || TREE_CODE (first) == CONVERT_EXPR
4977           || TREE_CODE (first) == NON_LVALUE_EXPR)
4978          && (TYPE_MODE (TREE_TYPE (first))
4979              == TYPE_MODE (TREE_TYPE (TREE_OPERAND (first, 0)))))
4980     first = TREE_OPERAND (first, 0);
4981
4982   if (last)
4983     while ((TREE_CODE (last) == NOP_EXPR
4984             || TREE_CODE (last) == CONVERT_EXPR
4985             || TREE_CODE (last) == NON_LVALUE_EXPR)
4986            && (TYPE_MODE (TREE_TYPE (last))
4987                == TYPE_MODE (TREE_TYPE (TREE_OPERAND (last, 0)))))
4988       last = TREE_OPERAND (last, 0);
4989
4990   if (TREE_CODE (first) != INTEGER_CST)
4991     error_init ("nonconstant array index in initializer");
4992   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
4993     error_init ("nonconstant array index in initializer");
4994   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
4995     error_init ("array index in non-array initializer");
4996   else if (tree_int_cst_sgn (first) == -1)
4997     error_init ("array index in initializer exceeds array bounds");
4998   else if (constructor_max_index
4999            && tree_int_cst_lt (constructor_max_index, first))
5000     error_init ("array index in initializer exceeds array bounds");
5001   else
5002     {
5003       constructor_index = convert (bitsizetype, first);
5004
5005       if (last)
5006         {
5007           if (tree_int_cst_equal (first, last))
5008             last = 0;
5009           else if (tree_int_cst_lt (last, first))
5010             {
5011               error_init ("empty index range in initializer");
5012               last = 0;
5013             }
5014           else
5015             {
5016               last = convert (bitsizetype, last);
5017               if (constructor_max_index != 0
5018                   && tree_int_cst_lt (constructor_max_index, last))
5019                 {
5020                   error_init ("array index range in initializer exceeds array bounds");
5021                   last = 0;
5022                 }
5023             }
5024         }
5025
5026       designator_depth++;
5027       designator_errorneous = 0;
5028       if (constructor_range_stack || last)
5029         push_range_stack (last);
5030     }
5031 }
5032
5033 /* Within a struct initializer, specify the next field to be initialized.  */
5034
5035 void
5036 set_init_label (tree fieldname)
5037 {
5038   tree tail;
5039
5040   if (set_designator (0))
5041     return;
5042
5043   designator_errorneous = 1;
5044
5045   if (TREE_CODE (constructor_type) != RECORD_TYPE
5046       && TREE_CODE (constructor_type) != UNION_TYPE)
5047     {
5048       error_init ("field name not in record or union initializer");
5049       return;
5050     }
5051
5052   for (tail = TYPE_FIELDS (constructor_type); tail;
5053        tail = TREE_CHAIN (tail))
5054     {
5055       if (DECL_NAME (tail) == fieldname)
5056         break;
5057     }
5058
5059   if (tail == 0)
5060     error ("unknown field `%s' specified in initializer",
5061            IDENTIFIER_POINTER (fieldname));
5062   else
5063     {
5064       constructor_fields = tail;
5065       designator_depth++;
5066       designator_errorneous = 0;
5067       if (constructor_range_stack)
5068         push_range_stack (NULL_TREE);
5069     }
5070 }
5071 \f
5072 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5073    identifies the initializer, either array index or field in a structure.
5074    VALUE is the value of that index or field.  */
5075
5076 static void
5077 add_pending_init (tree purpose, tree value)
5078 {
5079   struct init_node *p, **q, *r;
5080
5081   q = &constructor_pending_elts;
5082   p = 0;
5083
5084   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5085     {
5086       while (*q != 0)
5087         {
5088           p = *q;
5089           if (tree_int_cst_lt (purpose, p->purpose))
5090             q = &p->left;
5091           else if (tree_int_cst_lt (p->purpose, purpose))
5092             q = &p->right;
5093           else
5094             {
5095               if (TREE_SIDE_EFFECTS (p->value))
5096                 warning_init ("initialized field with side-effects overwritten");
5097               p->value = value;
5098               return;
5099             }
5100         }
5101     }
5102   else
5103     {
5104       tree bitpos;
5105
5106       bitpos = bit_position (purpose);
5107       while (*q != NULL)
5108         {
5109           p = *q;
5110           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5111             q = &p->left;
5112           else if (p->purpose != purpose)
5113             q = &p->right;
5114           else
5115             {
5116               if (TREE_SIDE_EFFECTS (p->value))
5117                 warning_init ("initialized field with side-effects overwritten");
5118               p->value = value;
5119               return;
5120             }
5121         }
5122     }
5123
5124   r = GGC_NEW (struct init_node);
5125   r->purpose = purpose;
5126   r->value = value;
5127
5128   *q = r;
5129   r->parent = p;
5130   r->left = 0;
5131   r->right = 0;
5132   r->balance = 0;
5133
5134   while (p)
5135     {
5136       struct init_node *s;
5137
5138       if (r == p->left)
5139         {
5140           if (p->balance == 0)
5141             p->balance = -1;
5142           else if (p->balance < 0)
5143             {
5144               if (r->balance < 0)
5145                 {
5146                   /* L rotation.  */
5147                   p->left = r->right;
5148                   if (p->left)
5149                     p->left->parent = p;
5150                   r->right = p;
5151
5152                   p->balance = 0;
5153                   r->balance = 0;
5154
5155                   s = p->parent;
5156                   p->parent = r;
5157                   r->parent = s;
5158                   if (s)
5159                     {
5160                       if (s->left == p)
5161                         s->left = r;
5162                       else
5163                         s->right = r;
5164                     }
5165                   else
5166                     constructor_pending_elts = r;
5167                 }
5168               else
5169                 {
5170                   /* LR rotation.  */
5171                   struct init_node *t = r->right;
5172
5173                   r->right = t->left;
5174                   if (r->right)
5175                     r->right->parent = r;
5176                   t->left = r;
5177
5178                   p->left = t->right;
5179                   if (p->left)
5180                     p->left->parent = p;
5181                   t->right = p;
5182
5183                   p->balance = t->balance < 0;
5184                   r->balance = -(t->balance > 0);
5185                   t->balance = 0;
5186
5187                   s = p->parent;
5188                   p->parent = t;
5189                   r->parent = t;
5190                   t->parent = s;
5191                   if (s)
5192                     {
5193                       if (s->left == p)
5194                         s->left = t;
5195                       else
5196                         s->right = t;
5197                     }
5198                   else
5199                     constructor_pending_elts = t;
5200                 }
5201               break;
5202             }
5203           else
5204             {
5205               /* p->balance == +1; growth of left side balances the node.  */
5206               p->balance = 0;
5207               break;
5208             }
5209         }
5210       else /* r == p->right */
5211         {
5212           if (p->balance == 0)
5213             /* Growth propagation from right side.  */
5214             p->balance++;
5215           else if (p->balance > 0)
5216             {
5217               if (r->balance > 0)
5218                 {
5219                   /* R rotation.  */
5220                   p->right = r->left;
5221                   if (p->right)
5222                     p->right->parent = p;
5223                   r->left = p;
5224
5225                   p->balance = 0;
5226                   r->balance = 0;
5227
5228                   s = p->parent;
5229                   p->parent = r;
5230                   r->parent = s;
5231                   if (s)
5232                     {
5233                       if (s->left == p)
5234                         s->left = r;
5235                       else
5236                         s->right = r;
5237                     }
5238                   else
5239                     constructor_pending_elts = r;
5240                 }
5241               else /* r->balance == -1 */
5242                 {
5243                   /* RL rotation */
5244                   struct init_node *t = r->left;
5245
5246                   r->left = t->right;
5247                   if (r->left)
5248                     r->left->parent = r;
5249                   t->right = r;
5250
5251                   p->right = t->left;
5252                   if (p->right)
5253                     p->right->parent = p;
5254                   t->left = p;
5255
5256                   r->balance = (t->balance < 0);
5257                   p->balance = -(t->balance > 0);
5258                   t->balance = 0;
5259
5260                   s = p->parent;
5261                   p->parent = t;
5262                   r->parent = t;
5263                   t->parent = s;
5264                   if (s)
5265                     {
5266                       if (s->left == p)
5267                         s->left = t;
5268                       else
5269                         s->right = t;
5270                     }
5271                   else
5272                     constructor_pending_elts = t;
5273                 }
5274               break;
5275             }
5276           else
5277             {
5278               /* p->balance == -1; growth of right side balances the node.  */
5279               p->balance = 0;
5280               break;
5281             }
5282         }
5283
5284       r = p;
5285       p = p->parent;
5286     }
5287 }
5288
5289 /* Build AVL tree from a sorted chain.  */
5290
5291 static void
5292 set_nonincremental_init (void)
5293 {
5294   tree chain;
5295
5296   if (TREE_CODE (constructor_type) != RECORD_TYPE
5297       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5298     return;
5299
5300   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5301     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5302   constructor_elements = 0;
5303   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5304     {
5305       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5306       /* Skip any nameless bit fields at the beginning.  */
5307       while (constructor_unfilled_fields != 0
5308              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5309              && DECL_NAME (constructor_unfilled_fields) == 0)
5310         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5311
5312     }
5313   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5314     {
5315       if (TYPE_DOMAIN (constructor_type))
5316         constructor_unfilled_index
5317             = convert (bitsizetype,
5318                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5319       else
5320         constructor_unfilled_index = bitsize_zero_node;
5321     }
5322   constructor_incremental = 0;
5323 }
5324
5325 /* Build AVL tree from a string constant.  */
5326
5327 static void
5328 set_nonincremental_init_from_string (tree str)
5329 {
5330   tree value, purpose, type;
5331   HOST_WIDE_INT val[2];
5332   const char *p, *end;
5333   int byte, wchar_bytes, charwidth, bitpos;
5334
5335   if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5336     abort ();
5337
5338   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5339       == TYPE_PRECISION (char_type_node))
5340     wchar_bytes = 1;
5341   else if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5342            == TYPE_PRECISION (wchar_type_node))
5343     wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5344   else
5345     abort ();
5346
5347   charwidth = TYPE_PRECISION (char_type_node);
5348   type = TREE_TYPE (constructor_type);
5349   p = TREE_STRING_POINTER (str);
5350   end = p + TREE_STRING_LENGTH (str);
5351
5352   for (purpose = bitsize_zero_node;
5353        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5354        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5355     {
5356       if (wchar_bytes == 1)
5357         {
5358           val[1] = (unsigned char) *p++;
5359           val[0] = 0;
5360         }
5361       else
5362         {
5363           val[0] = 0;
5364           val[1] = 0;
5365           for (byte = 0; byte < wchar_bytes; byte++)
5366             {
5367               if (BYTES_BIG_ENDIAN)
5368                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5369               else
5370                 bitpos = byte * charwidth;
5371               val[bitpos < HOST_BITS_PER_WIDE_INT]
5372                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5373                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5374             }
5375         }
5376
5377       if (!TYPE_UNSIGNED (type))
5378         {
5379           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5380           if (bitpos < HOST_BITS_PER_WIDE_INT)
5381             {
5382               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5383                 {
5384                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5385                   val[0] = -1;
5386                 }
5387             }
5388           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5389             {
5390               if (val[1] < 0)
5391                 val[0] = -1;
5392             }
5393           else if (val[0] & (((HOST_WIDE_INT) 1)
5394                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5395             val[0] |= ((HOST_WIDE_INT) -1)
5396                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5397         }
5398
5399       value = build_int_cst (type, val[1], val[0]);
5400       add_pending_init (purpose, value);
5401     }
5402
5403   constructor_incremental = 0;
5404 }
5405
5406 /* Return value of FIELD in pending initializer or zero if the field was
5407    not initialized yet.  */
5408
5409 static tree
5410 find_init_member (tree field)
5411 {
5412   struct init_node *p;
5413
5414   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5415     {
5416       if (constructor_incremental
5417           && tree_int_cst_lt (field, constructor_unfilled_index))
5418         set_nonincremental_init ();
5419
5420       p = constructor_pending_elts;
5421       while (p)
5422         {
5423           if (tree_int_cst_lt (field, p->purpose))
5424             p = p->left;
5425           else if (tree_int_cst_lt (p->purpose, field))
5426             p = p->right;
5427           else
5428             return p->value;
5429         }
5430     }
5431   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5432     {
5433       tree bitpos = bit_position (field);
5434
5435       if (constructor_incremental
5436           && (!constructor_unfilled_fields
5437               || tree_int_cst_lt (bitpos,
5438                                   bit_position (constructor_unfilled_fields))))
5439         set_nonincremental_init ();
5440
5441       p = constructor_pending_elts;
5442       while (p)
5443         {
5444           if (field == p->purpose)
5445             return p->value;
5446           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5447             p = p->left;
5448           else
5449             p = p->right;
5450         }
5451     }
5452   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5453     {
5454       if (constructor_elements
5455           && TREE_PURPOSE (constructor_elements) == field)
5456         return TREE_VALUE (constructor_elements);
5457     }
5458   return 0;
5459 }
5460
5461 /* "Output" the next constructor element.
5462    At top level, really output it to assembler code now.
5463    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5464    TYPE is the data type that the containing data type wants here.
5465    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5466    If VALUE is a string constant, STRICT_STRING is true if it is
5467    unparenthesized or we should not warn here for it being parenthesized.
5468    For other types of VALUE, STRICT_STRING is not used.
5469
5470    PENDING if non-nil means output pending elements that belong
5471    right after this element.  (PENDING is normally 1;
5472    it is 0 while outputting pending elements, to avoid recursion.)  */
5473
5474 static void
5475 output_init_element (tree value, bool strict_string, tree type, tree field,
5476                      int pending)
5477 {
5478   if (type == error_mark_node)
5479     {
5480       constructor_erroneous = 1;
5481       return;
5482     }
5483   if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
5484       || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5485           && !(TREE_CODE (value) == STRING_CST
5486                && TREE_CODE (type) == ARRAY_TYPE
5487                && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5488           && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5489                          TYPE_MAIN_VARIANT (type))))
5490     value = default_conversion (value);
5491
5492   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5493       && require_constant_value && !flag_isoc99 && pending)
5494     {
5495       /* As an extension, allow initializing objects with static storage
5496          duration with compound literals (which are then treated just as
5497          the brace enclosed list they contain).  */
5498       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5499       value = DECL_INITIAL (decl);
5500     }
5501
5502   if (value == error_mark_node)
5503     constructor_erroneous = 1;
5504   else if (!TREE_CONSTANT (value))
5505     constructor_constant = 0;
5506   else if (initializer_constant_valid_p (value, TREE_TYPE (value)) == 0
5507            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5508                 || TREE_CODE (constructor_type) == UNION_TYPE)
5509                && DECL_C_BIT_FIELD (field)
5510                && TREE_CODE (value) != INTEGER_CST))
5511     constructor_simple = 0;
5512
5513   if (require_constant_value && ! TREE_CONSTANT (value))
5514     {
5515       error_init ("initializer element is not constant");
5516       value = error_mark_node;
5517     }
5518   else if (require_constant_elements
5519            && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
5520     pedwarn ("initializer element is not computable at load time");
5521
5522   /* If this field is empty (and not at the end of structure),
5523      don't do anything other than checking the initializer.  */
5524   if (field
5525       && (TREE_TYPE (field) == error_mark_node
5526           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5527               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5528               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5529                   || TREE_CHAIN (field)))))
5530     return;
5531
5532   value = digest_init (type, value, strict_string, require_constant_value);
5533   if (value == error_mark_node)
5534     {
5535       constructor_erroneous = 1;
5536       return;
5537     }
5538
5539   /* If this element doesn't come next in sequence,
5540      put it on constructor_pending_elts.  */
5541   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5542       && (!constructor_incremental
5543           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5544     {
5545       if (constructor_incremental
5546           && tree_int_cst_lt (field, constructor_unfilled_index))
5547         set_nonincremental_init ();
5548
5549       add_pending_init (field, value);
5550       return;
5551     }
5552   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5553            && (!constructor_incremental
5554                || field != constructor_unfilled_fields))
5555     {
5556       /* We do this for records but not for unions.  In a union,
5557          no matter which field is specified, it can be initialized
5558          right away since it starts at the beginning of the union.  */
5559       if (constructor_incremental)
5560         {
5561           if (!constructor_unfilled_fields)
5562             set_nonincremental_init ();
5563           else
5564             {
5565               tree bitpos, unfillpos;
5566
5567               bitpos = bit_position (field);
5568               unfillpos = bit_position (constructor_unfilled_fields);
5569
5570               if (tree_int_cst_lt (bitpos, unfillpos))
5571                 set_nonincremental_init ();
5572             }
5573         }
5574
5575       add_pending_init (field, value);
5576       return;
5577     }
5578   else if (TREE_CODE (constructor_type) == UNION_TYPE
5579            && constructor_elements)
5580     {
5581       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5582         warning_init ("initialized field with side-effects overwritten");
5583
5584       /* We can have just one union field set.  */
5585       constructor_elements = 0;
5586     }
5587
5588   /* Otherwise, output this element either to
5589      constructor_elements or to the assembler file.  */
5590
5591   if (field && TREE_CODE (field) == INTEGER_CST)
5592     field = copy_node (field);
5593   constructor_elements
5594     = tree_cons (field, value, constructor_elements);
5595
5596   /* Advance the variable that indicates sequential elements output.  */
5597   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5598     constructor_unfilled_index
5599       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5600                     bitsize_one_node);
5601   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5602     {
5603       constructor_unfilled_fields
5604         = TREE_CHAIN (constructor_unfilled_fields);
5605
5606       /* Skip any nameless bit fields.  */
5607       while (constructor_unfilled_fields != 0
5608              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5609              && DECL_NAME (constructor_unfilled_fields) == 0)
5610         constructor_unfilled_fields =
5611           TREE_CHAIN (constructor_unfilled_fields);
5612     }
5613   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5614     constructor_unfilled_fields = 0;
5615
5616   /* Now output any pending elements which have become next.  */
5617   if (pending)
5618     output_pending_init_elements (0);
5619 }
5620
5621 /* Output any pending elements which have become next.
5622    As we output elements, constructor_unfilled_{fields,index}
5623    advances, which may cause other elements to become next;
5624    if so, they too are output.
5625
5626    If ALL is 0, we return when there are
5627    no more pending elements to output now.
5628
5629    If ALL is 1, we output space as necessary so that
5630    we can output all the pending elements.  */
5631
5632 static void
5633 output_pending_init_elements (int all)
5634 {
5635   struct init_node *elt = constructor_pending_elts;
5636   tree next;
5637
5638  retry:
5639
5640   /* Look through the whole pending tree.
5641      If we find an element that should be output now,
5642      output it.  Otherwise, set NEXT to the element
5643      that comes first among those still pending.  */
5644
5645   next = 0;
5646   while (elt)
5647     {
5648       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5649         {
5650           if (tree_int_cst_equal (elt->purpose,
5651                                   constructor_unfilled_index))
5652             output_init_element (elt->value, true,
5653                                  TREE_TYPE (constructor_type),
5654                                  constructor_unfilled_index, 0);
5655           else if (tree_int_cst_lt (constructor_unfilled_index,
5656                                     elt->purpose))
5657             {
5658               /* Advance to the next smaller node.  */
5659               if (elt->left)
5660                 elt = elt->left;
5661               else
5662                 {
5663                   /* We have reached the smallest node bigger than the
5664                      current unfilled index.  Fill the space first.  */
5665                   next = elt->purpose;
5666                   break;
5667                 }
5668             }
5669           else
5670             {
5671               /* Advance to the next bigger node.  */
5672               if (elt->right)
5673                 elt = elt->right;
5674               else
5675                 {
5676                   /* We have reached the biggest node in a subtree.  Find
5677                      the parent of it, which is the next bigger node.  */
5678                   while (elt->parent && elt->parent->right == elt)
5679                     elt = elt->parent;
5680                   elt = elt->parent;
5681                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5682                                               elt->purpose))
5683                     {
5684                       next = elt->purpose;
5685                       break;
5686                     }
5687                 }
5688             }
5689         }
5690       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5691                || TREE_CODE (constructor_type) == UNION_TYPE)
5692         {
5693           tree ctor_unfilled_bitpos, elt_bitpos;
5694
5695           /* If the current record is complete we are done.  */
5696           if (constructor_unfilled_fields == 0)
5697             break;
5698
5699           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5700           elt_bitpos = bit_position (elt->purpose);
5701           /* We can't compare fields here because there might be empty
5702              fields in between.  */
5703           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
5704             {
5705               constructor_unfilled_fields = elt->purpose;
5706               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
5707                                    elt->purpose, 0);
5708             }
5709           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
5710             {
5711               /* Advance to the next smaller node.  */
5712               if (elt->left)
5713                 elt = elt->left;
5714               else
5715                 {
5716                   /* We have reached the smallest node bigger than the
5717                      current unfilled field.  Fill the space first.  */
5718                   next = elt->purpose;
5719                   break;
5720                 }
5721             }
5722           else
5723             {
5724               /* Advance to the next bigger node.  */
5725               if (elt->right)
5726                 elt = elt->right;
5727               else
5728                 {
5729                   /* We have reached the biggest node in a subtree.  Find
5730                      the parent of it, which is the next bigger node.  */
5731                   while (elt->parent && elt->parent->right == elt)
5732                     elt = elt->parent;
5733                   elt = elt->parent;
5734                   if (elt
5735                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
5736                                            bit_position (elt->purpose))))
5737                     {
5738                       next = elt->purpose;
5739                       break;
5740                     }
5741                 }
5742             }
5743         }
5744     }
5745
5746   /* Ordinarily return, but not if we want to output all
5747      and there are elements left.  */
5748   if (! (all && next != 0))
5749     return;
5750
5751   /* If it's not incremental, just skip over the gap, so that after
5752      jumping to retry we will output the next successive element.  */
5753   if (TREE_CODE (constructor_type) == RECORD_TYPE
5754       || TREE_CODE (constructor_type) == UNION_TYPE)
5755     constructor_unfilled_fields = next;
5756   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5757     constructor_unfilled_index = next;
5758
5759   /* ELT now points to the node in the pending tree with the next
5760      initializer to output.  */
5761   goto retry;
5762 }
5763 \f
5764 /* Add one non-braced element to the current constructor level.
5765    This adjusts the current position within the constructor's type.
5766    This may also start or terminate implicit levels
5767    to handle a partly-braced initializer.
5768
5769    Once this has found the correct level for the new element,
5770    it calls output_init_element.  */
5771
5772 void
5773 process_init_element (struct c_expr value)
5774 {
5775   tree orig_value = value.value;
5776   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
5777   bool strict_string = value.original_code == STRING_CST;
5778
5779   designator_depth = 0;
5780   designator_errorneous = 0;
5781
5782   /* Handle superfluous braces around string cst as in
5783      char x[] = {"foo"}; */
5784   if (string_flag
5785       && constructor_type
5786       && TREE_CODE (constructor_type) == ARRAY_TYPE
5787       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
5788       && integer_zerop (constructor_unfilled_index))
5789     {
5790       if (constructor_stack->replacement_value.value)
5791         error_init ("excess elements in char array initializer");
5792       constructor_stack->replacement_value = value;
5793       return;
5794     }
5795
5796   if (constructor_stack->replacement_value.value != 0)
5797     {
5798       error_init ("excess elements in struct initializer");
5799       return;
5800     }
5801
5802   /* Ignore elements of a brace group if it is entirely superfluous
5803      and has already been diagnosed.  */
5804   if (constructor_type == 0)
5805     return;
5806
5807   /* If we've exhausted any levels that didn't have braces,
5808      pop them now.  */
5809   while (constructor_stack->implicit)
5810     {
5811       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5812            || TREE_CODE (constructor_type) == UNION_TYPE)
5813           && constructor_fields == 0)
5814         process_init_element (pop_init_level (1));
5815       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5816                && (constructor_max_index == 0
5817                    || tree_int_cst_lt (constructor_max_index,
5818                                        constructor_index)))
5819         process_init_element (pop_init_level (1));
5820       else
5821         break;
5822     }
5823
5824   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
5825   if (constructor_range_stack)
5826     {
5827       /* If value is a compound literal and we'll be just using its
5828          content, don't put it into a SAVE_EXPR.  */
5829       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
5830           || !require_constant_value
5831           || flag_isoc99)
5832         value.value = save_expr (value.value);
5833     }
5834
5835   while (1)
5836     {
5837       if (TREE_CODE (constructor_type) == RECORD_TYPE)
5838         {
5839           tree fieldtype;
5840           enum tree_code fieldcode;
5841
5842           if (constructor_fields == 0)
5843             {
5844               pedwarn_init ("excess elements in struct initializer");
5845               break;
5846             }
5847
5848           fieldtype = TREE_TYPE (constructor_fields);
5849           if (fieldtype != error_mark_node)
5850             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5851           fieldcode = TREE_CODE (fieldtype);
5852
5853           /* Error for non-static initialization of a flexible array member.  */
5854           if (fieldcode == ARRAY_TYPE
5855               && !require_constant_value
5856               && TYPE_SIZE (fieldtype) == NULL_TREE
5857               && TREE_CHAIN (constructor_fields) == NULL_TREE)
5858             {
5859               error_init ("non-static initialization of a flexible array member");
5860               break;
5861             }
5862
5863           /* Accept a string constant to initialize a subarray.  */
5864           if (value.value != 0
5865               && fieldcode == ARRAY_TYPE
5866               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
5867               && string_flag)
5868             value.value = orig_value;
5869           /* Otherwise, if we have come to a subaggregate,
5870              and we don't have an element of its type, push into it.  */
5871           else if (value.value != 0 && !constructor_no_implicit
5872                    && value.value != error_mark_node
5873                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5874                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5875                        || fieldcode == UNION_TYPE))
5876             {
5877               push_init_level (1);
5878               continue;
5879             }
5880
5881           if (value.value)
5882             {
5883               push_member_name (constructor_fields);
5884               output_init_element (value.value, strict_string,
5885                                    fieldtype, constructor_fields, 1);
5886               RESTORE_SPELLING_DEPTH (constructor_depth);
5887             }
5888           else
5889             /* Do the bookkeeping for an element that was
5890                directly output as a constructor.  */
5891             {
5892               /* For a record, keep track of end position of last field.  */
5893               if (DECL_SIZE (constructor_fields))
5894                 constructor_bit_index
5895                   = size_binop (PLUS_EXPR,
5896                                 bit_position (constructor_fields),
5897                                 DECL_SIZE (constructor_fields));
5898
5899               /* If the current field was the first one not yet written out,
5900                  it isn't now, so update.  */
5901               if (constructor_unfilled_fields == constructor_fields)
5902                 {
5903                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5904                   /* Skip any nameless bit fields.  */
5905                   while (constructor_unfilled_fields != 0
5906                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5907                          && DECL_NAME (constructor_unfilled_fields) == 0)
5908                     constructor_unfilled_fields =
5909                       TREE_CHAIN (constructor_unfilled_fields);
5910                 }
5911             }
5912
5913           constructor_fields = TREE_CHAIN (constructor_fields);
5914           /* Skip any nameless bit fields at the beginning.  */
5915           while (constructor_fields != 0
5916                  && DECL_C_BIT_FIELD (constructor_fields)
5917                  && DECL_NAME (constructor_fields) == 0)
5918             constructor_fields = TREE_CHAIN (constructor_fields);
5919         }
5920       else if (TREE_CODE (constructor_type) == UNION_TYPE)
5921         {
5922           tree fieldtype;
5923           enum tree_code fieldcode;
5924
5925           if (constructor_fields == 0)
5926             {
5927               pedwarn_init ("excess elements in union initializer");
5928               break;
5929             }
5930
5931           fieldtype = TREE_TYPE (constructor_fields);
5932           if (fieldtype != error_mark_node)
5933             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5934           fieldcode = TREE_CODE (fieldtype);
5935
5936           /* Warn that traditional C rejects initialization of unions.
5937              We skip the warning if the value is zero.  This is done
5938              under the assumption that the zero initializer in user
5939              code appears conditioned on e.g. __STDC__ to avoid
5940              "missing initializer" warnings and relies on default
5941              initialization to zero in the traditional C case.
5942              We also skip the warning if the initializer is designated,
5943              again on the assumption that this must be conditional on
5944              __STDC__ anyway (and we've already complained about the
5945              member-designator already).  */
5946           if (warn_traditional && !in_system_header && !constructor_designated
5947               && !(value.value && (integer_zerop (value.value)
5948                                    || real_zerop (value.value))))
5949             warning ("traditional C rejects initialization of unions");
5950
5951           /* Accept a string constant to initialize a subarray.  */
5952           if (value.value != 0
5953               && fieldcode == ARRAY_TYPE
5954               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
5955               && string_flag)
5956             value.value = orig_value;
5957           /* Otherwise, if we have come to a subaggregate,
5958              and we don't have an element of its type, push into it.  */
5959           else if (value.value != 0 && !constructor_no_implicit
5960                    && value.value != error_mark_node
5961                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5962                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5963                        || fieldcode == UNION_TYPE))
5964             {
5965               push_init_level (1);
5966               continue;
5967             }
5968
5969           if (value.value)
5970             {
5971               push_member_name (constructor_fields);
5972               output_init_element (value.value, strict_string,
5973                                    fieldtype, constructor_fields, 1);
5974               RESTORE_SPELLING_DEPTH (constructor_depth);
5975             }
5976           else
5977             /* Do the bookkeeping for an element that was
5978                directly output as a constructor.  */
5979             {
5980               constructor_bit_index = DECL_SIZE (constructor_fields);
5981               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5982             }
5983
5984           constructor_fields = 0;
5985         }
5986       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5987         {
5988           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5989           enum tree_code eltcode = TREE_CODE (elttype);
5990
5991           /* Accept a string constant to initialize a subarray.  */
5992           if (value.value != 0
5993               && eltcode == ARRAY_TYPE
5994               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
5995               && string_flag)
5996             value.value = orig_value;
5997           /* Otherwise, if we have come to a subaggregate,
5998              and we don't have an element of its type, push into it.  */
5999           else if (value.value != 0 && !constructor_no_implicit
6000                    && value.value != error_mark_node
6001                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6002                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6003                        || eltcode == UNION_TYPE))
6004             {
6005               push_init_level (1);
6006               continue;
6007             }
6008
6009           if (constructor_max_index != 0
6010               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6011                   || integer_all_onesp (constructor_max_index)))
6012             {
6013               pedwarn_init ("excess elements in array initializer");
6014               break;
6015             }
6016
6017           /* Now output the actual element.  */
6018           if (value.value)
6019             {
6020               push_array_bounds (tree_low_cst (constructor_index, 0));
6021               output_init_element (value.value, strict_string,
6022                                    elttype, constructor_index, 1);
6023               RESTORE_SPELLING_DEPTH (constructor_depth);
6024             }
6025
6026           constructor_index
6027             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6028
6029           if (!value.value)
6030             /* If we are doing the bookkeeping for an element that was
6031                directly output as a constructor, we must update
6032                constructor_unfilled_index.  */
6033             constructor_unfilled_index = constructor_index;
6034         }
6035       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6036         {
6037           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6038
6039          /* Do a basic check of initializer size.  Note that vectors
6040             always have a fixed size derived from their type.  */
6041           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6042             {
6043               pedwarn_init ("excess elements in vector initializer");
6044               break;
6045             }
6046
6047           /* Now output the actual element.  */
6048           if (value.value)
6049             output_init_element (value.value, strict_string,
6050                                  elttype, constructor_index, 1);
6051
6052           constructor_index
6053             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6054
6055           if (!value.value)
6056             /* If we are doing the bookkeeping for an element that was
6057                directly output as a constructor, we must update
6058                constructor_unfilled_index.  */
6059             constructor_unfilled_index = constructor_index;
6060         }
6061
6062       /* Handle the sole element allowed in a braced initializer
6063          for a scalar variable.  */
6064       else if (constructor_fields == 0)
6065         {
6066           pedwarn_init ("excess elements in scalar initializer");
6067           break;
6068         }
6069       else
6070         {
6071           if (value.value)
6072             output_init_element (value.value, strict_string,
6073                                  constructor_type, NULL_TREE, 1);
6074           constructor_fields = 0;
6075         }
6076
6077       /* Handle range initializers either at this level or anywhere higher
6078          in the designator stack.  */
6079       if (constructor_range_stack)
6080         {
6081           struct constructor_range_stack *p, *range_stack;
6082           int finish = 0;
6083
6084           range_stack = constructor_range_stack;
6085           constructor_range_stack = 0;
6086           while (constructor_stack != range_stack->stack)
6087             {
6088               if (!constructor_stack->implicit)
6089                 abort ();
6090               process_init_element (pop_init_level (1));
6091             }
6092           for (p = range_stack;
6093                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6094                p = p->prev)
6095             {
6096               if (!constructor_stack->implicit)
6097                 abort ();
6098               process_init_element (pop_init_level (1));
6099             }
6100
6101           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6102           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6103             finish = 1;
6104
6105           while (1)
6106             {
6107               constructor_index = p->index;
6108               constructor_fields = p->fields;
6109               if (finish && p->range_end && p->index == p->range_start)
6110                 {
6111                   finish = 0;
6112                   p->prev = 0;
6113                 }
6114               p = p->next;
6115               if (!p)
6116                 break;
6117               push_init_level (2);
6118               p->stack = constructor_stack;
6119               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6120                 p->index = p->range_start;
6121             }
6122
6123           if (!finish)
6124             constructor_range_stack = range_stack;
6125           continue;
6126         }
6127
6128       break;
6129     }
6130
6131   constructor_range_stack = 0;
6132 }
6133 \f
6134 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6135    (guaranteed to be 'volatile' or null) and ARGS (represented using
6136    an ASM_EXPR node).  */
6137 tree
6138 build_asm_stmt (tree cv_qualifier, tree args)
6139 {
6140   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6141     ASM_VOLATILE_P (args) = 1;
6142   return add_stmt (args);
6143 }
6144
6145 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6146    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6147    SIMPLE indicates whether there was anything at all after the
6148    string in the asm expression -- asm("blah") and asm("blah" : )
6149    are subtly different.  We use a ASM_EXPR node to represent this.  */
6150 tree
6151 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6152                 bool simple)
6153 {
6154   tree tail;
6155   tree args;
6156   int i;
6157   const char *constraint;
6158   bool allows_mem, allows_reg, is_inout;
6159   int ninputs;
6160   int noutputs;
6161
6162   ninputs = list_length (inputs);
6163   noutputs = list_length (outputs);
6164
6165   /* Remove output conversions that change the type but not the mode.  */
6166   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6167     {
6168       tree output = TREE_VALUE (tail);
6169       STRIP_NOPS (output);
6170       TREE_VALUE (tail) = output;
6171       lvalue_or_else (output, "invalid lvalue in asm statement");
6172
6173       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6174
6175       if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
6176                                     &allows_mem, &allows_reg, &is_inout))
6177         {
6178           /* By marking this operand as erroneous, we will not try
6179           to process this operand again in expand_asm_operands.  */
6180           TREE_VALUE (tail) = error_mark_node;
6181           continue;
6182         }
6183
6184       /* If the operand is a DECL that is going to end up in
6185         memory, assume it is addressable.  This is a bit more
6186         conservative than it would ideally be; the exact test is
6187         buried deep in expand_asm_operands and depends on the
6188         DECL_RTL for the OPERAND -- which we don't have at this
6189         point.  */
6190       if (!allows_reg && DECL_P (output))
6191         c_mark_addressable (output);
6192     }
6193
6194   /* Perform default conversions on array and function inputs.
6195      Don't do this for other types as it would screw up operands
6196      expected to be in memory.  */
6197   for (tail = inputs; tail; tail = TREE_CHAIN (tail))
6198     TREE_VALUE (tail) = default_function_array_conversion (TREE_VALUE (tail));
6199
6200   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6201
6202   /* Simple asm statements are treated as volatile.  */
6203   if (simple)
6204     {
6205       ASM_VOLATILE_P (args) = 1;
6206       ASM_INPUT_P (args) = 1;
6207     }
6208   return args;
6209 }
6210 \f
6211 /* Generate a goto statement to LABEL.  */
6212
6213 tree
6214 c_finish_goto_label (tree label)
6215 {
6216   tree decl = lookup_label (label);
6217   if (!decl)
6218     return NULL_TREE;
6219
6220   TREE_USED (decl) = 1;
6221   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6222 }
6223
6224 /* Generate a computed goto statement to EXPR.  */
6225
6226 tree
6227 c_finish_goto_ptr (tree expr)
6228 {
6229   if (pedantic)
6230     pedwarn ("ISO C forbids `goto *expr;'");
6231   expr = convert (ptr_type_node, expr);
6232   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6233 }
6234
6235 /* Generate a C `return' statement.  RETVAL is the expression for what
6236    to return, or a null pointer for `return;' with no value.  */
6237
6238 tree
6239 c_finish_return (tree retval)
6240 {
6241   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6242
6243   if (TREE_THIS_VOLATILE (current_function_decl))
6244     warning ("function declared `noreturn' has a `return' statement");
6245
6246   if (!retval)
6247     {
6248       current_function_returns_null = 1;
6249       if ((warn_return_type || flag_isoc99)
6250           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6251         pedwarn_c99 ("`return' with no value, in function returning non-void");
6252     }
6253   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6254     {
6255       current_function_returns_null = 1;
6256       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6257         pedwarn ("`return' with a value, in function returning void");
6258     }
6259   else
6260     {
6261       tree t = convert_for_assignment (valtype, retval, _("return"),
6262                                        NULL_TREE, NULL_TREE, 0);
6263       tree res = DECL_RESULT (current_function_decl);
6264       tree inner;
6265
6266       current_function_returns_value = 1;
6267       if (t == error_mark_node)
6268         return NULL_TREE;
6269
6270       inner = t = convert (TREE_TYPE (res), t);
6271
6272       /* Strip any conversions, additions, and subtractions, and see if
6273          we are returning the address of a local variable.  Warn if so.  */
6274       while (1)
6275         {
6276           switch (TREE_CODE (inner))
6277             {
6278             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6279             case PLUS_EXPR:
6280               inner = TREE_OPERAND (inner, 0);
6281               continue;
6282
6283             case MINUS_EXPR:
6284               /* If the second operand of the MINUS_EXPR has a pointer
6285                  type (or is converted from it), this may be valid, so
6286                  don't give a warning.  */
6287               {
6288                 tree op1 = TREE_OPERAND (inner, 1);
6289
6290                 while (! POINTER_TYPE_P (TREE_TYPE (op1))
6291                        && (TREE_CODE (op1) == NOP_EXPR
6292                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6293                            || TREE_CODE (op1) == CONVERT_EXPR))
6294                   op1 = TREE_OPERAND (op1, 0);
6295
6296                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6297                   break;
6298
6299                 inner = TREE_OPERAND (inner, 0);
6300                 continue;
6301               }
6302
6303             case ADDR_EXPR:
6304               inner = TREE_OPERAND (inner, 0);
6305
6306               while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
6307                 inner = TREE_OPERAND (inner, 0);
6308
6309               if (DECL_P (inner)
6310                   && ! DECL_EXTERNAL (inner)
6311                   && ! TREE_STATIC (inner)
6312                   && DECL_CONTEXT (inner) == current_function_decl)
6313                 warning ("function returns address of local variable");
6314               break;
6315
6316             default:
6317               break;
6318             }
6319
6320           break;
6321         }
6322
6323       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6324     }
6325
6326   return add_stmt (build_stmt (RETURN_EXPR, retval));
6327 }
6328 \f
6329 struct c_switch {
6330   /* The SWITCH_STMT being built.  */
6331   tree switch_stmt;
6332
6333   /* The original type of the testing expression, ie. before the
6334      default conversion is applied.  */
6335   tree orig_type;
6336
6337   /* A splay-tree mapping the low element of a case range to the high
6338      element, or NULL_TREE if there is no high element.  Used to
6339      determine whether or not a new case label duplicates an old case
6340      label.  We need a tree, rather than simply a hash table, because
6341      of the GNU case range extension.  */
6342   splay_tree cases;
6343
6344   /* The next node on the stack.  */
6345   struct c_switch *next;
6346 };
6347
6348 /* A stack of the currently active switch statements.  The innermost
6349    switch statement is on the top of the stack.  There is no need to
6350    mark the stack for garbage collection because it is only active
6351    during the processing of the body of a function, and we never
6352    collect at that point.  */
6353
6354 struct c_switch *c_switch_stack;
6355
6356 /* Start a C switch statement, testing expression EXP.  Return the new
6357    SWITCH_STMT.  */
6358
6359 tree
6360 c_start_case (tree exp)
6361 {
6362   enum tree_code code;
6363   tree type, orig_type = error_mark_node;
6364   struct c_switch *cs;
6365
6366   if (exp != error_mark_node)
6367     {
6368       code = TREE_CODE (TREE_TYPE (exp));
6369       orig_type = TREE_TYPE (exp);
6370
6371       if (! INTEGRAL_TYPE_P (orig_type)
6372           && code != ERROR_MARK)
6373         {
6374           error ("switch quantity not an integer");
6375           exp = integer_zero_node;
6376         }
6377       else
6378         {
6379           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6380
6381           if (warn_traditional && !in_system_header
6382               && (type == long_integer_type_node
6383                   || type == long_unsigned_type_node))
6384             warning ("`long' switch expression not converted to `int' in ISO C");
6385
6386           exp = default_conversion (exp);
6387           type = TREE_TYPE (exp);
6388         }
6389     }
6390
6391   /* Add this new SWITCH_STMT to the stack.  */
6392   cs = XNEW (struct c_switch);
6393   cs->switch_stmt = build_stmt ((enum tree_code) SWITCH_STMT, exp, NULL_TREE,
6394                                 orig_type);
6395   cs->orig_type = orig_type;
6396   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6397   cs->next = c_switch_stack;
6398   c_switch_stack = cs;
6399
6400   return add_stmt (cs->switch_stmt);
6401 }
6402
6403 /* Process a case label.  */
6404
6405 tree
6406 do_case (tree low_value, tree high_value)
6407 {
6408   tree label = NULL_TREE;
6409
6410   if (c_switch_stack)
6411     {
6412       label = c_add_case_label (c_switch_stack->cases,
6413                                 SWITCH_COND (c_switch_stack->switch_stmt),
6414                                 c_switch_stack->orig_type,
6415                                 low_value, high_value);
6416       if (label == error_mark_node)
6417         label = NULL_TREE;
6418     }
6419   else if (low_value)
6420     error ("case label not within a switch statement");
6421   else
6422     error ("`default' label not within a switch statement");
6423
6424   return label;
6425 }
6426
6427 /* Finish the switch statement.  */
6428
6429 void
6430 c_finish_case (tree body)
6431 {
6432   struct c_switch *cs = c_switch_stack;
6433
6434   SWITCH_BODY (cs->switch_stmt) = body;
6435
6436   /* Emit warnings as needed.  */
6437   c_do_switch_warnings (cs->cases, cs->switch_stmt);
6438
6439   /* Pop the stack.  */
6440   c_switch_stack = cs->next;
6441   splay_tree_delete (cs->cases);
6442   XDELETE (cs);
6443 }
6444 \f
6445 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6446    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6447    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6448    statement, and was not surrounded with parenthesis.  */
6449
6450 void
6451 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6452                   tree else_block, bool nested_if)
6453 {
6454   tree stmt;
6455
6456   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6457   if (warn_parentheses && nested_if && else_block == NULL)
6458     {
6459       tree inner_if = then_block;
6460
6461       /* We know from the grammar productions that there is an IF nested
6462          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6463          it might not be exactly THEN_BLOCK, but should be the last
6464          non-container statement within.  */
6465       while (1)
6466         switch (TREE_CODE (inner_if))
6467           {
6468           case COND_EXPR:
6469             goto found;
6470           case BIND_EXPR:
6471             inner_if = BIND_EXPR_BODY (inner_if);
6472             break;
6473           case STATEMENT_LIST:
6474             inner_if = expr_last (then_block);
6475             break;
6476           case TRY_FINALLY_EXPR:
6477           case TRY_CATCH_EXPR:
6478             inner_if = TREE_OPERAND (inner_if, 0);
6479             break;
6480           default:
6481             abort ();
6482           }
6483     found:
6484
6485       if (COND_EXPR_ELSE (inner_if))
6486          warning ("%Hsuggest explicit braces to avoid ambiguous `else'",
6487                   &if_locus);
6488     }
6489
6490   /* Diagnose ";" via the special empty statement node that we create.  */
6491   if (extra_warnings)
6492     {
6493       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6494         {
6495           if (!else_block)
6496             warning ("%Hempty body in an if-statement",
6497                      EXPR_LOCUS (then_block));
6498           then_block = alloc_stmt_list ();
6499         }
6500       if (else_block
6501           && TREE_CODE (else_block) == NOP_EXPR
6502           && !TREE_TYPE (else_block))
6503         {
6504           warning ("%Hempty body in an else-statement",
6505                    EXPR_LOCUS (else_block));
6506           else_block = alloc_stmt_list ();
6507         }
6508     }
6509
6510   stmt = build3 (COND_EXPR, NULL_TREE, cond, then_block, else_block);
6511   SET_EXPR_LOCATION (stmt, if_locus);
6512   add_stmt (stmt);
6513 }
6514
6515 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6516    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6517    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6518    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6519    the continue label.  Everything is allowed to be NULL.  */
6520
6521 void
6522 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6523                tree blab, tree clab, bool cond_is_first)
6524 {
6525   tree entry = NULL, exit = NULL, t;
6526
6527   /* Detect do { ... } while (0) and don't generate loop construct.  */
6528   if (cond && !cond_is_first && integer_zerop (cond))
6529     cond = NULL;
6530   if (cond_is_first || cond)
6531     {
6532       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6533
6534       /* If we have an exit condition, then we build an IF with gotos either
6535          out of the loop, or to the top of it.  If there's no exit condition,
6536          then we just build a jump back to the top.  */
6537       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6538
6539       if (cond)
6540         {
6541           /* Canonicalize the loop condition to the end.  This means
6542              generating a branch to the loop condition.  Reuse the
6543              continue label, if possible.  */
6544           if (cond_is_first)
6545             {
6546               if (incr || !clab)
6547                 {
6548                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6549                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6550                 }
6551               else
6552                 t = build1 (GOTO_EXPR, void_type_node, clab);
6553               SET_EXPR_LOCATION (t, start_locus);
6554               add_stmt (t);
6555             }
6556
6557           t = build_and_jump (&blab);
6558           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
6559           exit = fold (exit);
6560           if (cond_is_first)
6561             SET_EXPR_LOCATION (exit, start_locus);
6562           else
6563             SET_EXPR_LOCATION (exit, input_location);
6564         }
6565
6566       add_stmt (top);
6567     }
6568
6569   if (body)
6570     add_stmt (body);
6571   if (clab)
6572     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
6573   if (incr)
6574     add_stmt (incr);
6575   if (entry)
6576     add_stmt (entry);
6577   if (exit)
6578     add_stmt (exit);
6579   if (blab)
6580     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
6581 }
6582
6583 tree
6584 c_finish_bc_stmt (tree *label_p, bool is_break)
6585 {
6586   tree label = *label_p;
6587
6588   if (!label)
6589     *label_p = label = create_artificial_label ();
6590   else if (TREE_CODE (label) != LABEL_DECL)
6591     {
6592       if (is_break)
6593         error ("break statement not within loop or switch");
6594       else
6595         error ("continue statement not within a loop");
6596       return NULL_TREE;
6597     }
6598
6599   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
6600 }
6601
6602 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
6603
6604 static void
6605 emit_side_effect_warnings (tree expr)
6606 {
6607   if (expr == error_mark_node)
6608     ;
6609   else if (!TREE_SIDE_EFFECTS (expr))
6610     {
6611       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
6612         warning ("%Hstatement with no effect",
6613                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
6614     }
6615   else if (warn_unused_value)
6616     warn_if_unused_value (expr, input_location);
6617 }
6618
6619 /* Process an expression as if it were a complete statement.  Emit
6620    diagnostics, but do not call ADD_STMT.  */
6621
6622 tree
6623 c_process_expr_stmt (tree expr)
6624 {
6625   if (!expr)
6626     return NULL_TREE;
6627
6628   /* Do default conversion if safe and possibly important,
6629      in case within ({...}).  */
6630   if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
6631        && (flag_isoc99 || lvalue_p (expr)))
6632       || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE)
6633     expr = default_conversion (expr);
6634
6635   if (warn_sequence_point)
6636     verify_sequence_points (expr);
6637
6638   if (TREE_TYPE (expr) != error_mark_node
6639       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
6640       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
6641     error ("expression statement has incomplete type");
6642
6643   /* If we're not processing a statement expression, warn about unused values.
6644      Warnings for statement expressions will be emitted later, once we figure
6645      out which is the result.  */
6646   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6647       && (extra_warnings || warn_unused_value))
6648     emit_side_effect_warnings (expr);
6649
6650   /* If the expression is not of a type to which we cannot assign a line
6651      number, wrap the thing in a no-op NOP_EXPR.  */
6652   if (DECL_P (expr) || TREE_CODE_CLASS (TREE_CODE (expr)) == 'c')
6653     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
6654
6655   if (EXPR_P (expr))
6656     SET_EXPR_LOCATION (expr, input_location);
6657
6658   return expr;
6659 }
6660
6661 /* Emit an expression as a statement.  */
6662
6663 tree
6664 c_finish_expr_stmt (tree expr)
6665 {
6666   if (expr)
6667     return add_stmt (c_process_expr_stmt (expr));
6668   else
6669     return NULL;
6670 }
6671
6672 /* Do the opposite and emit a statement as an expression.  To begin,
6673    create a new binding level and return it.  */
6674
6675 tree
6676 c_begin_stmt_expr (void)
6677 {
6678   tree ret;
6679
6680   /* We must force a BLOCK for this level so that, if it is not expanded
6681      later, there is a way to turn off the entire subtree of blocks that
6682      are contained in it.  */
6683   keep_next_level ();
6684   ret = c_begin_compound_stmt (true);
6685
6686   /* Mark the current statement list as belonging to a statement list.  */
6687   STATEMENT_LIST_STMT_EXPR (ret) = 1;
6688
6689   return ret;
6690 }
6691
6692 tree
6693 c_finish_stmt_expr (tree body)
6694 {
6695   tree last, type, tmp, val;
6696   tree *last_p;
6697
6698   body = c_end_compound_stmt (body, true);
6699
6700   /* Locate the last statement in BODY.  See c_end_compound_stmt
6701      about always returning a BIND_EXPR.  */
6702   last_p = &BIND_EXPR_BODY (body);
6703   last = BIND_EXPR_BODY (body);
6704
6705  continue_searching:
6706   if (TREE_CODE (last) == STATEMENT_LIST)
6707     {
6708       tree_stmt_iterator i;
6709
6710       /* This can happen with degenerate cases like ({ }).  No value.  */
6711       if (!TREE_SIDE_EFFECTS (last))
6712         return body;
6713
6714       /* If we're supposed to generate side effects warnings, process
6715          all of the statements except the last.  */
6716       if (extra_warnings || warn_unused_value)
6717         {
6718           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
6719             emit_side_effect_warnings (tsi_stmt (i));
6720         }
6721       else
6722         i = tsi_last (last);
6723       last_p = tsi_stmt_ptr (i);
6724       last = *last_p;
6725     }
6726
6727   /* If the end of the list is exception related, then the list was split
6728      by a call to push_cleanup.  Continue searching.  */
6729   if (TREE_CODE (last) == TRY_FINALLY_EXPR
6730       || TREE_CODE (last) == TRY_CATCH_EXPR)
6731     {
6732       last_p = &TREE_OPERAND (last, 0);
6733       last = *last_p;
6734       goto continue_searching;
6735     }
6736
6737   /* In the case that the BIND_EXPR is not necessary, return the
6738      expression out from inside it.  */
6739   if (last == error_mark_node
6740       || (last == BIND_EXPR_BODY (body)
6741           && BIND_EXPR_VARS (body) == NULL))
6742     return last;
6743
6744   /* Extract the type of said expression.  */
6745   type = TREE_TYPE (last);
6746
6747   /* If we're not returning a value at all, then the BIND_EXPR that
6748      we already have is a fine expression to return.  */
6749   if (!type || VOID_TYPE_P (type))
6750     return body;
6751
6752   /* Now that we've located the expression containing the value, it seems
6753      silly to make voidify_wrapper_expr repeat the process.  Create a
6754      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
6755   tmp = create_tmp_var_raw (type, NULL);
6756
6757   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
6758      tree_expr_nonnegative_p giving up immediately.  */
6759   val = last;
6760   if (TREE_CODE (val) == NOP_EXPR
6761       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
6762     val = TREE_OPERAND (val, 0);
6763
6764   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
6765   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
6766
6767   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
6768 }
6769 \f
6770 /* Begin and end compound statements.  This is as simple as pushing
6771    and popping new statement lists from the tree.  */
6772
6773 tree
6774 c_begin_compound_stmt (bool do_scope)
6775 {
6776   tree stmt = push_stmt_list ();
6777   if (do_scope)
6778     push_scope ();
6779   return stmt;
6780 }
6781
6782 tree
6783 c_end_compound_stmt (tree stmt, bool do_scope)
6784 {
6785   tree block = NULL;
6786
6787   if (do_scope)
6788     {
6789       if (c_dialect_objc ())
6790         objc_clear_super_receiver ();
6791       block = pop_scope ();
6792     }
6793
6794   stmt = pop_stmt_list (stmt);
6795   stmt = c_build_bind_expr (block, stmt);
6796
6797   /* If this compound statement is nested immediately inside a statement
6798      expression, then force a BIND_EXPR to be created.  Otherwise we'll
6799      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
6800      STATEMENT_LISTs merge, and thus we can lose track of what statement
6801      was really last.  */
6802   if (cur_stmt_list
6803       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6804       && TREE_CODE (stmt) != BIND_EXPR)
6805     {
6806       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
6807       TREE_SIDE_EFFECTS (stmt) = 1;
6808     }
6809
6810   return stmt;
6811 }
6812
6813 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
6814    when the current scope is exited.  EH_ONLY is true when this is not
6815    meant to apply to normal control flow transfer.  */
6816
6817 void
6818 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
6819 {
6820   enum tree_code code;
6821   tree stmt, list;
6822   bool stmt_expr;
6823
6824   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
6825   stmt = build_stmt (code, NULL, cleanup);
6826   add_stmt (stmt);
6827   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
6828   list = push_stmt_list ();
6829   TREE_OPERAND (stmt, 0) = list;
6830   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
6831 }
6832 \f
6833 /* Build a binary-operation expression without default conversions.
6834    CODE is the kind of expression to build.
6835    This function differs from `build' in several ways:
6836    the data type of the result is computed and recorded in it,
6837    warnings are generated if arg data types are invalid,
6838    special handling for addition and subtraction of pointers is known,
6839    and some optimization is done (operations on narrow ints
6840    are done in the narrower type when that gives the same result).
6841    Constant folding is also done before the result is returned.
6842
6843    Note that the operands will never have enumeral types, or function
6844    or array types, because either they will have the default conversions
6845    performed or they have both just been converted to some other type in which
6846    the arithmetic is to be done.  */
6847
6848 tree
6849 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
6850                  int convert_p)
6851 {
6852   tree type0, type1;
6853   enum tree_code code0, code1;
6854   tree op0, op1;
6855
6856   /* Expression code to give to the expression when it is built.
6857      Normally this is CODE, which is what the caller asked for,
6858      but in some special cases we change it.  */
6859   enum tree_code resultcode = code;
6860
6861   /* Data type in which the computation is to be performed.
6862      In the simplest cases this is the common type of the arguments.  */
6863   tree result_type = NULL;
6864
6865   /* Nonzero means operands have already been type-converted
6866      in whatever way is necessary.
6867      Zero means they need to be converted to RESULT_TYPE.  */
6868   int converted = 0;
6869
6870   /* Nonzero means create the expression with this type, rather than
6871      RESULT_TYPE.  */
6872   tree build_type = 0;
6873
6874   /* Nonzero means after finally constructing the expression
6875      convert it to this type.  */
6876   tree final_type = 0;
6877
6878   /* Nonzero if this is an operation like MIN or MAX which can
6879      safely be computed in short if both args are promoted shorts.
6880      Also implies COMMON.
6881      -1 indicates a bitwise operation; this makes a difference
6882      in the exact conditions for when it is safe to do the operation
6883      in a narrower mode.  */
6884   int shorten = 0;
6885
6886   /* Nonzero if this is a comparison operation;
6887      if both args are promoted shorts, compare the original shorts.
6888      Also implies COMMON.  */
6889   int short_compare = 0;
6890
6891   /* Nonzero if this is a right-shift operation, which can be computed on the
6892      original short and then promoted if the operand is a promoted short.  */
6893   int short_shift = 0;
6894
6895   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
6896   int common = 0;
6897
6898   if (convert_p)
6899     {
6900       op0 = default_conversion (orig_op0);
6901       op1 = default_conversion (orig_op1);
6902     }
6903   else
6904     {
6905       op0 = orig_op0;
6906       op1 = orig_op1;
6907     }
6908
6909   type0 = TREE_TYPE (op0);
6910   type1 = TREE_TYPE (op1);
6911
6912   /* The expression codes of the data types of the arguments tell us
6913      whether the arguments are integers, floating, pointers, etc.  */
6914   code0 = TREE_CODE (type0);
6915   code1 = TREE_CODE (type1);
6916
6917   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
6918   STRIP_TYPE_NOPS (op0);
6919   STRIP_TYPE_NOPS (op1);
6920
6921   /* If an error was already reported for one of the arguments,
6922      avoid reporting another error.  */
6923
6924   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
6925     return error_mark_node;
6926
6927   switch (code)
6928     {
6929     case PLUS_EXPR:
6930       /* Handle the pointer + int case.  */
6931       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6932         return pointer_int_sum (PLUS_EXPR, op0, op1);
6933       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
6934         return pointer_int_sum (PLUS_EXPR, op1, op0);
6935       else
6936         common = 1;
6937       break;
6938
6939     case MINUS_EXPR:
6940       /* Subtraction of two similar pointers.
6941          We must subtract them as integers, then divide by object size.  */
6942       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
6943           && comp_target_types (type0, type1, 1))
6944         return pointer_diff (op0, op1);
6945       /* Handle pointer minus int.  Just like pointer plus int.  */
6946       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6947         return pointer_int_sum (MINUS_EXPR, op0, op1);
6948       else
6949         common = 1;
6950       break;
6951
6952     case MULT_EXPR:
6953       common = 1;
6954       break;
6955
6956     case TRUNC_DIV_EXPR:
6957     case CEIL_DIV_EXPR:
6958     case FLOOR_DIV_EXPR:
6959     case ROUND_DIV_EXPR:
6960     case EXACT_DIV_EXPR:
6961       /* Floating point division by zero is a legitimate way to obtain
6962          infinities and NaNs.  */
6963       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6964         warning ("division by zero");
6965
6966       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
6967            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6968           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
6969               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
6970         {
6971           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6972             code0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
6973           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
6974             code1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
6975
6976           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
6977             resultcode = RDIV_EXPR;
6978           else
6979             /* Although it would be tempting to shorten always here, that
6980                loses on some targets, since the modulo instruction is
6981                undefined if the quotient can't be represented in the
6982                computation mode.  We shorten only if unsigned or if
6983                dividing by something we know != -1.  */
6984             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
6985                        || (TREE_CODE (op1) == INTEGER_CST
6986                            && ! integer_all_onesp (op1)));
6987           common = 1;
6988         }
6989       break;
6990
6991     case BIT_AND_EXPR:
6992     case BIT_IOR_EXPR:
6993     case BIT_XOR_EXPR:
6994       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
6995         shorten = -1;
6996       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
6997         common = 1;
6998       break;
6999
7000     case TRUNC_MOD_EXPR:
7001     case FLOOR_MOD_EXPR:
7002       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
7003         warning ("division by zero");
7004
7005       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7006         {
7007           /* Although it would be tempting to shorten always here, that loses
7008              on some targets, since the modulo instruction is undefined if the
7009              quotient can't be represented in the computation mode.  We shorten
7010              only if unsigned or if dividing by something we know != -1.  */
7011           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7012                      || (TREE_CODE (op1) == INTEGER_CST
7013                          && ! integer_all_onesp (op1)));
7014           common = 1;
7015         }
7016       break;
7017
7018     case TRUTH_ANDIF_EXPR:
7019     case TRUTH_ORIF_EXPR:
7020     case TRUTH_AND_EXPR:
7021     case TRUTH_OR_EXPR:
7022     case TRUTH_XOR_EXPR:
7023       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7024            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7025           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7026               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7027         {
7028           /* Result of these operations is always an int,
7029              but that does not mean the operands should be
7030              converted to ints!  */
7031           result_type = integer_type_node;
7032           op0 = lang_hooks.truthvalue_conversion (op0);
7033           op1 = lang_hooks.truthvalue_conversion (op1);
7034           converted = 1;
7035         }
7036       break;
7037
7038       /* Shift operations: result has same type as first operand;
7039          always convert second operand to int.
7040          Also set SHORT_SHIFT if shifting rightward.  */
7041
7042     case RSHIFT_EXPR:
7043       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7044         {
7045           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7046             {
7047               if (tree_int_cst_sgn (op1) < 0)
7048                 warning ("right shift count is negative");
7049               else
7050                 {
7051                   if (! integer_zerop (op1))
7052                     short_shift = 1;
7053
7054                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7055                     warning ("right shift count >= width of type");
7056                 }
7057             }
7058
7059           /* Use the type of the value to be shifted.  */
7060           result_type = type0;
7061           /* Convert the shift-count to an integer, regardless of size
7062              of value being shifted.  */
7063           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7064             op1 = convert (integer_type_node, op1);
7065           /* Avoid converting op1 to result_type later.  */
7066           converted = 1;
7067         }
7068       break;
7069
7070     case LSHIFT_EXPR:
7071       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7072         {
7073           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7074             {
7075               if (tree_int_cst_sgn (op1) < 0)
7076                 warning ("left shift count is negative");
7077
7078               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7079                 warning ("left shift count >= width of type");
7080             }
7081
7082           /* Use the type of the value to be shifted.  */
7083           result_type = type0;
7084           /* Convert the shift-count to an integer, regardless of size
7085              of value being shifted.  */
7086           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7087             op1 = convert (integer_type_node, op1);
7088           /* Avoid converting op1 to result_type later.  */
7089           converted = 1;
7090         }
7091       break;
7092
7093     case RROTATE_EXPR:
7094     case LROTATE_EXPR:
7095       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7096         {
7097           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7098             {
7099               if (tree_int_cst_sgn (op1) < 0)
7100                 warning ("shift count is negative");
7101               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7102                 warning ("shift count >= width of type");
7103             }
7104
7105           /* Use the type of the value to be shifted.  */
7106           result_type = type0;
7107           /* Convert the shift-count to an integer, regardless of size
7108              of value being shifted.  */
7109           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7110             op1 = convert (integer_type_node, op1);
7111           /* Avoid converting op1 to result_type later.  */
7112           converted = 1;
7113         }
7114       break;
7115
7116     case EQ_EXPR:
7117     case NE_EXPR:
7118       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
7119         warning ("comparing floating point with == or != is unsafe");
7120       /* Result of comparison is always int,
7121          but don't convert the args to int!  */
7122       build_type = integer_type_node;
7123       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7124            || code0 == COMPLEX_TYPE)
7125           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7126               || code1 == COMPLEX_TYPE))
7127         short_compare = 1;
7128       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7129         {
7130           tree tt0 = TREE_TYPE (type0);
7131           tree tt1 = TREE_TYPE (type1);
7132           /* Anything compares with void *.  void * compares with anything.
7133              Otherwise, the targets must be compatible
7134              and both must be object or both incomplete.  */
7135           if (comp_target_types (type0, type1, 1))
7136             result_type = common_pointer_type (type0, type1);
7137           else if (VOID_TYPE_P (tt0))
7138             {
7139               /* op0 != orig_op0 detects the case of something
7140                  whose value is 0 but which isn't a valid null ptr const.  */
7141               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7142                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7143                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7144             }
7145           else if (VOID_TYPE_P (tt1))
7146             {
7147               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7148                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7149                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7150             }
7151           else
7152             pedwarn ("comparison of distinct pointer types lacks a cast");
7153
7154           if (result_type == NULL_TREE)
7155             result_type = ptr_type_node;
7156         }
7157       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7158                && integer_zerop (op1))
7159         result_type = type0;
7160       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7161                && integer_zerop (op0))
7162         result_type = type1;
7163       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7164         {
7165           result_type = type0;
7166           pedwarn ("comparison between pointer and integer");
7167         }
7168       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7169         {
7170           result_type = type1;
7171           pedwarn ("comparison between pointer and integer");
7172         }
7173       break;
7174
7175     case MAX_EXPR:
7176     case MIN_EXPR:
7177       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7178           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7179         shorten = 1;
7180       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7181         {
7182           if (comp_target_types (type0, type1, 1))
7183             {
7184               result_type = common_pointer_type (type0, type1);
7185               if (pedantic
7186                   && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7187                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7188             }
7189           else
7190             {
7191               result_type = ptr_type_node;
7192               pedwarn ("comparison of distinct pointer types lacks a cast");
7193             }
7194         }
7195       break;
7196
7197     case LE_EXPR:
7198     case GE_EXPR:
7199     case LT_EXPR:
7200     case GT_EXPR:
7201       build_type = integer_type_node;
7202       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7203           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7204         short_compare = 1;
7205       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7206         {
7207           if (comp_target_types (type0, type1, 1))
7208             {
7209               result_type = common_pointer_type (type0, type1);
7210               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7211                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7212                 pedwarn ("comparison of complete and incomplete pointers");
7213               else if (pedantic
7214                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7215                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7216             }
7217           else
7218             {
7219               result_type = ptr_type_node;
7220               pedwarn ("comparison of distinct pointer types lacks a cast");
7221             }
7222         }
7223       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7224                && integer_zerop (op1))
7225         {
7226           result_type = type0;
7227           if (pedantic || extra_warnings)
7228             pedwarn ("ordered comparison of pointer with integer zero");
7229         }
7230       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7231                && integer_zerop (op0))
7232         {
7233           result_type = type1;
7234           if (pedantic)
7235             pedwarn ("ordered comparison of pointer with integer zero");
7236         }
7237       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7238         {
7239           result_type = type0;
7240           pedwarn ("comparison between pointer and integer");
7241         }
7242       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7243         {
7244           result_type = type1;
7245           pedwarn ("comparison between pointer and integer");
7246         }
7247       break;
7248
7249     case UNORDERED_EXPR:
7250     case ORDERED_EXPR:
7251     case UNLT_EXPR:
7252     case UNLE_EXPR:
7253     case UNGT_EXPR:
7254     case UNGE_EXPR:
7255     case UNEQ_EXPR:
7256     case LTGT_EXPR:
7257       build_type = integer_type_node;
7258       if (code0 != REAL_TYPE || code1 != REAL_TYPE)
7259         {
7260           error ("unordered comparison on non-floating point argument");
7261           return error_mark_node;
7262         }
7263       common = 1;
7264       break;
7265
7266     default:
7267       break;
7268     }
7269
7270   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7271     return error_mark_node;
7272
7273   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7274        || code0 == VECTOR_TYPE)
7275       &&
7276       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7277        || code1 == VECTOR_TYPE))
7278     {
7279       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7280
7281       if (shorten || common || short_compare)
7282         result_type = common_type (type0, type1);
7283
7284       /* For certain operations (which identify themselves by shorten != 0)
7285          if both args were extended from the same smaller type,
7286          do the arithmetic in that type and then extend.
7287
7288          shorten !=0 and !=1 indicates a bitwise operation.
7289          For them, this optimization is safe only if
7290          both args are zero-extended or both are sign-extended.
7291          Otherwise, we might change the result.
7292          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7293          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7294
7295       if (shorten && none_complex)
7296         {
7297           int unsigned0, unsigned1;
7298           tree arg0 = get_narrower (op0, &unsigned0);
7299           tree arg1 = get_narrower (op1, &unsigned1);
7300           /* UNS is 1 if the operation to be done is an unsigned one.  */
7301           int uns = TYPE_UNSIGNED (result_type);
7302           tree type;
7303
7304           final_type = result_type;
7305
7306           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7307              but it *requires* conversion to FINAL_TYPE.  */
7308
7309           if ((TYPE_PRECISION (TREE_TYPE (op0))
7310                == TYPE_PRECISION (TREE_TYPE (arg0)))
7311               && TREE_TYPE (op0) != final_type)
7312             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7313           if ((TYPE_PRECISION (TREE_TYPE (op1))
7314                == TYPE_PRECISION (TREE_TYPE (arg1)))
7315               && TREE_TYPE (op1) != final_type)
7316             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7317
7318           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7319
7320           /* For bitwise operations, signedness of nominal type
7321              does not matter.  Consider only how operands were extended.  */
7322           if (shorten == -1)
7323             uns = unsigned0;
7324
7325           /* Note that in all three cases below we refrain from optimizing
7326              an unsigned operation on sign-extended args.
7327              That would not be valid.  */
7328
7329           /* Both args variable: if both extended in same way
7330              from same width, do it in that width.
7331              Do it unsigned if args were zero-extended.  */
7332           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7333                < TYPE_PRECISION (result_type))
7334               && (TYPE_PRECISION (TREE_TYPE (arg1))
7335                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7336               && unsigned0 == unsigned1
7337               && (unsigned0 || !uns))
7338             result_type
7339               = c_common_signed_or_unsigned_type
7340               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7341           else if (TREE_CODE (arg0) == INTEGER_CST
7342                    && (unsigned1 || !uns)
7343                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7344                        < TYPE_PRECISION (result_type))
7345                    && (type
7346                        = c_common_signed_or_unsigned_type (unsigned1,
7347                                                            TREE_TYPE (arg1)),
7348                        int_fits_type_p (arg0, type)))
7349             result_type = type;
7350           else if (TREE_CODE (arg1) == INTEGER_CST
7351                    && (unsigned0 || !uns)
7352                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7353                        < TYPE_PRECISION (result_type))
7354                    && (type
7355                        = c_common_signed_or_unsigned_type (unsigned0,
7356                                                            TREE_TYPE (arg0)),
7357                        int_fits_type_p (arg1, type)))
7358             result_type = type;
7359         }
7360
7361       /* Shifts can be shortened if shifting right.  */
7362
7363       if (short_shift)
7364         {
7365           int unsigned_arg;
7366           tree arg0 = get_narrower (op0, &unsigned_arg);
7367
7368           final_type = result_type;
7369
7370           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7371             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7372
7373           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7374               /* We can shorten only if the shift count is less than the
7375                  number of bits in the smaller type size.  */
7376               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7377               /* We cannot drop an unsigned shift after sign-extension.  */
7378               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7379             {
7380               /* Do an unsigned shift if the operand was zero-extended.  */
7381               result_type
7382                 = c_common_signed_or_unsigned_type (unsigned_arg,
7383                                                     TREE_TYPE (arg0));
7384               /* Convert value-to-be-shifted to that type.  */
7385               if (TREE_TYPE (op0) != result_type)
7386                 op0 = convert (result_type, op0);
7387               converted = 1;
7388             }
7389         }
7390
7391       /* Comparison operations are shortened too but differently.
7392          They identify themselves by setting short_compare = 1.  */
7393
7394       if (short_compare)
7395         {
7396           /* Don't write &op0, etc., because that would prevent op0
7397              from being kept in a register.
7398              Instead, make copies of the our local variables and
7399              pass the copies by reference, then copy them back afterward.  */
7400           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7401           enum tree_code xresultcode = resultcode;
7402           tree val
7403             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7404
7405           if (val != 0)
7406             return val;
7407
7408           op0 = xop0, op1 = xop1;
7409           converted = 1;
7410           resultcode = xresultcode;
7411
7412           if (warn_sign_compare && skip_evaluation == 0)
7413             {
7414               int op0_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7415               int op1_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7416               int unsignedp0, unsignedp1;
7417               tree primop0 = get_narrower (op0, &unsignedp0);
7418               tree primop1 = get_narrower (op1, &unsignedp1);
7419
7420               xop0 = orig_op0;
7421               xop1 = orig_op1;
7422               STRIP_TYPE_NOPS (xop0);
7423               STRIP_TYPE_NOPS (xop1);
7424
7425               /* Give warnings for comparisons between signed and unsigned
7426                  quantities that may fail.
7427
7428                  Do the checking based on the original operand trees, so that
7429                  casts will be considered, but default promotions won't be.
7430
7431                  Do not warn if the comparison is being done in a signed type,
7432                  since the signed type will only be chosen if it can represent
7433                  all the values of the unsigned type.  */
7434               if (! TYPE_UNSIGNED (result_type))
7435                 /* OK */;
7436               /* Do not warn if both operands are the same signedness.  */
7437               else if (op0_signed == op1_signed)
7438                 /* OK */;
7439               else
7440                 {
7441                   tree sop, uop;
7442
7443                   if (op0_signed)
7444                     sop = xop0, uop = xop1;
7445                   else
7446                     sop = xop1, uop = xop0;
7447
7448                   /* Do not warn if the signed quantity is an
7449                      unsuffixed integer literal (or some static
7450                      constant expression involving such literals or a
7451                      conditional expression involving such literals)
7452                      and it is non-negative.  */
7453                   if (tree_expr_nonnegative_p (sop))
7454                     /* OK */;
7455                   /* Do not warn if the comparison is an equality operation,
7456                      the unsigned quantity is an integral constant, and it
7457                      would fit in the result if the result were signed.  */
7458                   else if (TREE_CODE (uop) == INTEGER_CST
7459                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7460                            && int_fits_type_p
7461                            (uop, c_common_signed_type (result_type)))
7462                     /* OK */;
7463                   /* Do not warn if the unsigned quantity is an enumeration
7464                      constant and its maximum value would fit in the result
7465                      if the result were signed.  */
7466                   else if (TREE_CODE (uop) == INTEGER_CST
7467                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7468                            && int_fits_type_p
7469                            (TYPE_MAX_VALUE (TREE_TYPE(uop)),
7470                             c_common_signed_type (result_type)))
7471                     /* OK */;
7472                   else
7473                     warning ("comparison between signed and unsigned");
7474                 }
7475
7476               /* Warn if two unsigned values are being compared in a size
7477                  larger than their original size, and one (and only one) is the
7478                  result of a `~' operator.  This comparison will always fail.
7479
7480                  Also warn if one operand is a constant, and the constant
7481                  does not have all bits set that are set in the ~ operand
7482                  when it is extended.  */
7483
7484               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7485                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7486                 {
7487                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7488                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7489                                             &unsignedp0);
7490                   else
7491                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7492                                             &unsignedp1);
7493
7494                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7495                     {
7496                       tree primop;
7497                       HOST_WIDE_INT constant, mask;
7498                       int unsignedp, bits;
7499
7500                       if (host_integerp (primop0, 0))
7501                         {
7502                           primop = primop1;
7503                           unsignedp = unsignedp1;
7504                           constant = tree_low_cst (primop0, 0);
7505                         }
7506                       else
7507                         {
7508                           primop = primop0;
7509                           unsignedp = unsignedp0;
7510                           constant = tree_low_cst (primop1, 0);
7511                         }
7512
7513                       bits = TYPE_PRECISION (TREE_TYPE (primop));
7514                       if (bits < TYPE_PRECISION (result_type)
7515                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
7516                         {
7517                           mask = (~ (HOST_WIDE_INT) 0) << bits;
7518                           if ((mask & constant) != mask)
7519                             warning ("comparison of promoted ~unsigned with constant");
7520                         }
7521                     }
7522                   else if (unsignedp0 && unsignedp1
7523                            && (TYPE_PRECISION (TREE_TYPE (primop0))
7524                                < TYPE_PRECISION (result_type))
7525                            && (TYPE_PRECISION (TREE_TYPE (primop1))
7526                                < TYPE_PRECISION (result_type)))
7527                     warning ("comparison of promoted ~unsigned with unsigned");
7528                 }
7529             }
7530         }
7531     }
7532
7533   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7534      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7535      Then the expression will be built.
7536      It will be given type FINAL_TYPE if that is nonzero;
7537      otherwise, it will be given type RESULT_TYPE.  */
7538
7539   if (!result_type)
7540     {
7541       binary_op_error (code);
7542       return error_mark_node;
7543     }
7544
7545   if (! converted)
7546     {
7547       if (TREE_TYPE (op0) != result_type)
7548         op0 = convert (result_type, op0);
7549       if (TREE_TYPE (op1) != result_type)
7550         op1 = convert (result_type, op1);
7551     }
7552
7553   if (build_type == NULL_TREE)
7554     build_type = result_type;
7555
7556   {
7557     tree result = build2 (resultcode, build_type, op0, op1);
7558
7559     /* Treat expressions in initializers specially as they can't trap.  */
7560     result = require_constant_value ? fold_initializer (result)
7561                                     : fold (result);
7562
7563     if (final_type != 0)
7564       result = convert (final_type, result);
7565     return result;
7566   }
7567 }
7568
7569 /* Build the result of __builtin_offsetof.  TYPE is the first argument to
7570    offsetof, i.e. a type.  LIST is a tree_list that encodes component and
7571    array references; PURPOSE is set for the former and VALUE is set for
7572    the later.  */
7573
7574 tree
7575 build_offsetof (tree type, tree list)
7576 {
7577   tree t;
7578
7579   /* Build "*(type *)0".  */
7580   t = convert (build_pointer_type (type), null_pointer_node);
7581   t = build_indirect_ref (t, "");
7582
7583   /* Build COMPONENT and ARRAY_REF expressions as needed.  */
7584   for (list = nreverse (list); list ; list = TREE_CHAIN (list))
7585     if (TREE_PURPOSE (list))
7586       t = build_component_ref (t, TREE_PURPOSE (list));
7587     else
7588       t = build_array_ref (t, TREE_VALUE (list));
7589
7590   /* Finalize the offsetof expression.  For now all we need to do is take
7591      the address of the expression we created, and cast that to an integer
7592      type; this mirrors the traditional macro implementation of offsetof.  */
7593   t = build_unary_op (ADDR_EXPR, t, 0);
7594   return convert (size_type_node, t);
7595 }