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             /* If the folded PLUS_EXPR is not a constant address, wrap
2543                it in an ADDR_EXPR.  */
2544             if (!TREE_CONSTANT (addr))
2545               addr = build1 (ADDR_EXPR, argtype, arg);
2546           }
2547         else
2548           addr = build1 (ADDR_EXPR, argtype, arg);
2549
2550         if (TREE_CODE (arg) == COMPOUND_LITERAL_EXPR)
2551           TREE_INVARIANT (addr) = TREE_CONSTANT (addr) = 1;
2552
2553         return addr;
2554       }
2555
2556     default:
2557       break;
2558     }
2559
2560   if (argtype == 0)
2561     argtype = TREE_TYPE (arg);
2562   val = build1 (code, argtype, arg);
2563   return require_constant_value ? fold_initializer (val) : fold (val);
2564 }
2565
2566 /* Return nonzero if REF is an lvalue valid for this language.
2567    Lvalues can be assigned, unless their type has TYPE_READONLY.
2568    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2569
2570 int
2571 lvalue_p (tree ref)
2572 {
2573   enum tree_code code = TREE_CODE (ref);
2574
2575   switch (code)
2576     {
2577     case REALPART_EXPR:
2578     case IMAGPART_EXPR:
2579     case COMPONENT_REF:
2580       return lvalue_p (TREE_OPERAND (ref, 0));
2581
2582     case COMPOUND_LITERAL_EXPR:
2583     case STRING_CST:
2584       return 1;
2585
2586     case INDIRECT_REF:
2587     case ARRAY_REF:
2588     case VAR_DECL:
2589     case PARM_DECL:
2590     case RESULT_DECL:
2591     case ERROR_MARK:
2592       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2593               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2594
2595     case BIND_EXPR:
2596       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2597
2598     default:
2599       return 0;
2600     }
2601 }
2602
2603 /* Return nonzero if REF is an lvalue valid for this language;
2604    otherwise, print an error message and return zero.  */
2605
2606 static int
2607 lvalue_or_else (tree ref, const char *msgid)
2608 {
2609   int win = lvalue_p (ref);
2610
2611   if (! win)
2612     error ("%s", msgid);
2613
2614   return win;
2615 }
2616
2617 \f
2618 /* Warn about storing in something that is `const'.  */
2619
2620 void
2621 readonly_error (tree arg, const char *msgid)
2622 {
2623   if (TREE_CODE (arg) == COMPONENT_REF)
2624     {
2625       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2626         readonly_error (TREE_OPERAND (arg, 0), msgid);
2627       else
2628         error ("%s of read-only member `%s'", _(msgid),
2629                IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (arg, 1))));
2630     }
2631   else if (TREE_CODE (arg) == VAR_DECL)
2632     error ("%s of read-only variable `%s'", _(msgid),
2633            IDENTIFIER_POINTER (DECL_NAME (arg)));
2634   else
2635     error ("%s of read-only location", _(msgid));
2636 }
2637 \f
2638 /* Mark EXP saying that we need to be able to take the
2639    address of it; it should not be allocated in a register.
2640    Returns true if successful.  */
2641
2642 bool
2643 c_mark_addressable (tree exp)
2644 {
2645   tree x = exp;
2646
2647   while (1)
2648     switch (TREE_CODE (x))
2649       {
2650       case COMPONENT_REF:
2651         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2652           {
2653             error ("cannot take address of bit-field `%s'",
2654                    IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (x, 1))));
2655             return false;
2656           }
2657
2658         /* ... fall through ...  */
2659
2660       case ADDR_EXPR:
2661       case ARRAY_REF:
2662       case REALPART_EXPR:
2663       case IMAGPART_EXPR:
2664         x = TREE_OPERAND (x, 0);
2665         break;
2666
2667       case COMPOUND_LITERAL_EXPR:
2668       case CONSTRUCTOR:
2669         TREE_ADDRESSABLE (x) = 1;
2670         return true;
2671
2672       case VAR_DECL:
2673       case CONST_DECL:
2674       case PARM_DECL:
2675       case RESULT_DECL:
2676         if (C_DECL_REGISTER (x)
2677             && DECL_NONLOCAL (x))
2678           {
2679             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2680               {
2681                 error ("global register variable `%s' used in nested function",
2682                        IDENTIFIER_POINTER (DECL_NAME (x)));
2683                 return false;
2684               }
2685             pedwarn ("register variable `%s' used in nested function",
2686                      IDENTIFIER_POINTER (DECL_NAME (x)));
2687           }
2688         else if (C_DECL_REGISTER (x))
2689           {
2690             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2691               {
2692                 error ("address of global register variable `%s' requested",
2693                        IDENTIFIER_POINTER (DECL_NAME (x)));
2694                 return false;
2695               }
2696
2697             pedwarn ("address of register variable `%s' requested",
2698                      IDENTIFIER_POINTER (DECL_NAME (x)));
2699           }
2700
2701         /* drops in */
2702       case FUNCTION_DECL:
2703         TREE_ADDRESSABLE (x) = 1;
2704         /* drops out */
2705       default:
2706         return true;
2707     }
2708 }
2709 \f
2710 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2711
2712 tree
2713 build_conditional_expr (tree ifexp, tree op1, tree op2)
2714 {
2715   tree type1;
2716   tree type2;
2717   enum tree_code code1;
2718   enum tree_code code2;
2719   tree result_type = NULL;
2720   tree orig_op1 = op1, orig_op2 = op2;
2721
2722   ifexp = lang_hooks.truthvalue_conversion (default_conversion (ifexp));
2723
2724   /* Promote both alternatives.  */
2725
2726   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2727     op1 = default_conversion (op1);
2728   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2729     op2 = default_conversion (op2);
2730
2731   if (TREE_CODE (ifexp) == ERROR_MARK
2732       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2733       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2734     return error_mark_node;
2735
2736   type1 = TREE_TYPE (op1);
2737   code1 = TREE_CODE (type1);
2738   type2 = TREE_TYPE (op2);
2739   code2 = TREE_CODE (type2);
2740
2741   /* C90 does not permit non-lvalue arrays in conditional expressions.
2742      In C99 they will be pointers by now.  */
2743   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2744     {
2745       error ("non-lvalue array in conditional expression");
2746       return error_mark_node;
2747     }
2748
2749   /* Quickly detect the usual case where op1 and op2 have the same type
2750      after promotion.  */
2751   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2752     {
2753       if (type1 == type2)
2754         result_type = type1;
2755       else
2756         result_type = TYPE_MAIN_VARIANT (type1);
2757     }
2758   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
2759             || code1 == COMPLEX_TYPE)
2760            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
2761                || code2 == COMPLEX_TYPE))
2762     {
2763       result_type = common_type (type1, type2);
2764
2765       /* If -Wsign-compare, warn here if type1 and type2 have
2766          different signedness.  We'll promote the signed to unsigned
2767          and later code won't know it used to be different.
2768          Do this check on the original types, so that explicit casts
2769          will be considered, but default promotions won't.  */
2770       if (warn_sign_compare && !skip_evaluation)
2771         {
2772           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
2773           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
2774
2775           if (unsigned_op1 ^ unsigned_op2)
2776             {
2777               /* Do not warn if the result type is signed, since the
2778                  signed type will only be chosen if it can represent
2779                  all the values of the unsigned type.  */
2780               if (! TYPE_UNSIGNED (result_type))
2781                 /* OK */;
2782               /* Do not warn if the signed quantity is an unsuffixed
2783                  integer literal (or some static constant expression
2784                  involving such literals) and it is non-negative.  */
2785               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
2786                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
2787                 /* OK */;
2788               else
2789                 warning ("signed and unsigned type in conditional expression");
2790             }
2791         }
2792     }
2793   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
2794     {
2795       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
2796         pedwarn ("ISO C forbids conditional expr with only one void side");
2797       result_type = void_type_node;
2798     }
2799   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
2800     {
2801       if (comp_target_types (type1, type2, 1))
2802         result_type = common_pointer_type (type1, type2);
2803       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
2804                && TREE_CODE (orig_op1) != NOP_EXPR)
2805         result_type = qualify_type (type2, type1);
2806       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
2807                && TREE_CODE (orig_op2) != NOP_EXPR)
2808         result_type = qualify_type (type1, type2);
2809       else if (VOID_TYPE_P (TREE_TYPE (type1)))
2810         {
2811           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
2812             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2813           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
2814                                                           TREE_TYPE (type2)));
2815         }
2816       else if (VOID_TYPE_P (TREE_TYPE (type2)))
2817         {
2818           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
2819             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2820           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
2821                                                           TREE_TYPE (type1)));
2822         }
2823       else
2824         {
2825           pedwarn ("pointer type mismatch in conditional expression");
2826           result_type = build_pointer_type (void_type_node);
2827         }
2828     }
2829   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
2830     {
2831       if (! integer_zerop (op2))
2832         pedwarn ("pointer/integer type mismatch in conditional expression");
2833       else
2834         {
2835           op2 = null_pointer_node;
2836         }
2837       result_type = type1;
2838     }
2839   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
2840     {
2841       if (!integer_zerop (op1))
2842         pedwarn ("pointer/integer type mismatch in conditional expression");
2843       else
2844         {
2845           op1 = null_pointer_node;
2846         }
2847       result_type = type2;
2848     }
2849
2850   if (!result_type)
2851     {
2852       if (flag_cond_mismatch)
2853         result_type = void_type_node;
2854       else
2855         {
2856           error ("type mismatch in conditional expression");
2857           return error_mark_node;
2858         }
2859     }
2860
2861   /* Merge const and volatile flags of the incoming types.  */
2862   result_type
2863     = build_type_variant (result_type,
2864                           TREE_READONLY (op1) || TREE_READONLY (op2),
2865                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
2866
2867   if (result_type != TREE_TYPE (op1))
2868     op1 = convert_and_check (result_type, op1);
2869   if (result_type != TREE_TYPE (op2))
2870     op2 = convert_and_check (result_type, op2);
2871
2872   if (TREE_CODE (ifexp) == INTEGER_CST)
2873     return non_lvalue (integer_zerop (ifexp) ? op2 : op1);
2874
2875   return fold (build3 (COND_EXPR, result_type, ifexp, op1, op2));
2876 }
2877 \f
2878 /* Return a compound expression that performs two expressions and
2879    returns the value of the second of them.  */
2880
2881 tree
2882 build_compound_expr (tree expr1, tree expr2)
2883 {
2884   /* Convert arrays and functions to pointers.  */
2885   expr2 = default_function_array_conversion (expr2);
2886
2887   /* Don't let (0, 0) be null pointer constant.  */
2888   if (integer_zerop (expr2))
2889     expr2 = non_lvalue (expr2);
2890
2891   if (! TREE_SIDE_EFFECTS (expr1))
2892     {
2893       /* The left-hand operand of a comma expression is like an expression
2894          statement: with -Wextra or -Wunused, we should warn if it doesn't have
2895          any side-effects, unless it was explicitly cast to (void).  */
2896       if (warn_unused_value
2897            && ! (TREE_CODE (expr1) == CONVERT_EXPR
2898                 && VOID_TYPE_P (TREE_TYPE (expr1))))
2899         warning ("left-hand operand of comma expression has no effect");
2900     }
2901
2902   /* With -Wunused, we should also warn if the left-hand operand does have
2903      side-effects, but computes a value which is not used.  For example, in
2904      `foo() + bar(), baz()' the result of the `+' operator is not used,
2905      so we should issue a warning.  */
2906   else if (warn_unused_value)
2907     warn_if_unused_value (expr1, input_location);
2908
2909   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
2910 }
2911
2912 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
2913
2914 tree
2915 build_c_cast (tree type, tree expr)
2916 {
2917   tree value = expr;
2918
2919   if (type == error_mark_node || expr == error_mark_node)
2920     return error_mark_node;
2921
2922   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
2923      only in <protocol> qualifications.  But when constructing cast expressions,
2924      the protocols do matter and must be kept around.  */
2925   if (!c_dialect_objc () || !objc_is_object_ptr (type))
2926     type = TYPE_MAIN_VARIANT (type);
2927
2928   if (TREE_CODE (type) == ARRAY_TYPE)
2929     {
2930       error ("cast specifies array type");
2931       return error_mark_node;
2932     }
2933
2934   if (TREE_CODE (type) == FUNCTION_TYPE)
2935     {
2936       error ("cast specifies function type");
2937       return error_mark_node;
2938     }
2939
2940   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
2941     {
2942       if (pedantic)
2943         {
2944           if (TREE_CODE (type) == RECORD_TYPE
2945               || TREE_CODE (type) == UNION_TYPE)
2946             pedwarn ("ISO C forbids casting nonscalar to the same type");
2947         }
2948     }
2949   else if (TREE_CODE (type) == UNION_TYPE)
2950     {
2951       tree field;
2952       value = default_function_array_conversion (value);
2953
2954       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
2955         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
2956                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
2957           break;
2958
2959       if (field)
2960         {
2961           tree t;
2962
2963           if (pedantic)
2964             pedwarn ("ISO C forbids casts to union type");
2965           t = digest_init (type,
2966                            build_constructor (type,
2967                                               build_tree_list (field, value)),
2968                            true, 0);
2969           TREE_CONSTANT (t) = TREE_CONSTANT (value);
2970           TREE_INVARIANT (t) = TREE_INVARIANT (value);
2971           return t;
2972         }
2973       error ("cast to union type from type not present in union");
2974       return error_mark_node;
2975     }
2976   else
2977     {
2978       tree otype, ovalue;
2979
2980       /* If casting to void, avoid the error that would come
2981          from default_conversion in the case of a non-lvalue array.  */
2982       if (type == void_type_node)
2983         return build1 (CONVERT_EXPR, type, value);
2984
2985       /* Convert functions and arrays to pointers,
2986          but don't convert any other types.  */
2987       value = default_function_array_conversion (value);
2988       otype = TREE_TYPE (value);
2989
2990       /* Optionally warn about potentially worrisome casts.  */
2991
2992       if (warn_cast_qual
2993           && TREE_CODE (type) == POINTER_TYPE
2994           && TREE_CODE (otype) == POINTER_TYPE)
2995         {
2996           tree in_type = type;
2997           tree in_otype = otype;
2998           int added = 0;
2999           int discarded = 0;
3000
3001           /* Check that the qualifiers on IN_TYPE are a superset of
3002              the qualifiers of IN_OTYPE.  The outermost level of
3003              POINTER_TYPE nodes is uninteresting and we stop as soon
3004              as we hit a non-POINTER_TYPE node on either type.  */
3005           do
3006             {
3007               in_otype = TREE_TYPE (in_otype);
3008               in_type = TREE_TYPE (in_type);
3009
3010               /* GNU C allows cv-qualified function types.  'const'
3011                  means the function is very pure, 'volatile' means it
3012                  can't return.  We need to warn when such qualifiers
3013                  are added, not when they're taken away.  */
3014               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3015                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3016                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3017               else
3018                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3019             }
3020           while (TREE_CODE (in_type) == POINTER_TYPE
3021                  && TREE_CODE (in_otype) == POINTER_TYPE);
3022
3023           if (added)
3024             warning ("cast adds new qualifiers to function type");
3025
3026           if (discarded)
3027             /* There are qualifiers present in IN_OTYPE that are not
3028                present in IN_TYPE.  */
3029             warning ("cast discards qualifiers from pointer target type");
3030         }
3031
3032       /* Warn about possible alignment problems.  */
3033       if (STRICT_ALIGNMENT && warn_cast_align
3034           && TREE_CODE (type) == POINTER_TYPE
3035           && TREE_CODE (otype) == POINTER_TYPE
3036           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3037           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3038           /* Don't warn about opaque types, where the actual alignment
3039              restriction is unknown.  */
3040           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3041                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3042                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3043           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3044         warning ("cast increases required alignment of target type");
3045
3046       if (TREE_CODE (type) == INTEGER_TYPE
3047           && TREE_CODE (otype) == POINTER_TYPE
3048           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3049           && !TREE_CONSTANT (value))
3050         warning ("cast from pointer to integer of different size");
3051
3052       if (warn_bad_function_cast
3053           && TREE_CODE (value) == CALL_EXPR
3054           && TREE_CODE (type) != TREE_CODE (otype))
3055         warning ("cast does not match function type");
3056
3057       if (TREE_CODE (type) == POINTER_TYPE
3058           && TREE_CODE (otype) == INTEGER_TYPE
3059           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3060           /* Don't warn about converting any constant.  */
3061           && !TREE_CONSTANT (value))
3062         warning ("cast to pointer from integer of different size");
3063
3064       if (TREE_CODE (type) == POINTER_TYPE
3065           && TREE_CODE (otype) == POINTER_TYPE
3066           && TREE_CODE (expr) == ADDR_EXPR
3067           && DECL_P (TREE_OPERAND (expr, 0))
3068           && flag_strict_aliasing && warn_strict_aliasing
3069           && !VOID_TYPE_P (TREE_TYPE (type)))
3070         {
3071           /* Casting the address of a decl to non void pointer. Warn
3072              if the cast breaks type based aliasing.  */
3073           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3074             warning ("type-punning to incomplete type might break strict-aliasing rules");
3075           else
3076             {
3077               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3078               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3079
3080               if (!alias_sets_conflict_p (set1, set2))
3081                 warning ("dereferencing type-punned pointer will break strict-aliasing rules");
3082               else if (warn_strict_aliasing > 1
3083                        && !alias_sets_might_conflict_p (set1, set2))
3084                 warning ("dereferencing type-punned pointer might break strict-aliasing rules");
3085             }
3086         }
3087
3088       /* If pedantic, warn for conversions between function and object
3089          pointer types, except for converting a null pointer constant
3090          to function pointer type.  */
3091       if (pedantic
3092           && TREE_CODE (type) == POINTER_TYPE
3093           && TREE_CODE (otype) == POINTER_TYPE
3094           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3095           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3096         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3097
3098       if (pedantic
3099           && TREE_CODE (type) == POINTER_TYPE
3100           && TREE_CODE (otype) == POINTER_TYPE
3101           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3102           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3103           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3104                && TREE_CODE (expr) != NOP_EXPR))
3105         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3106
3107       ovalue = value;
3108       /* Replace a nonvolatile const static variable with its value.  */
3109       if (optimize && TREE_CODE (value) == VAR_DECL)
3110         value = decl_constant_value (value);
3111       value = convert (type, value);
3112
3113       /* Ignore any integer overflow caused by the cast.  */
3114       if (TREE_CODE (value) == INTEGER_CST)
3115         {
3116           if (EXPR_P (ovalue))
3117             /* If OVALUE had overflow set, then so will VALUE, so it
3118                is safe to overwrite.  */
3119             TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3120           else
3121             TREE_OVERFLOW (value) = 0;
3122
3123           if (TREE_CODE_CLASS (TREE_CODE (ovalue)) == 'c')
3124             /* Similarly, constant_overflow cannot have become
3125                cleared.  */
3126             TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3127         }
3128     }
3129
3130   /* Don't let (void *) (FOO *) 0 be a null pointer constant.  */
3131   if (TREE_CODE (value) == INTEGER_CST
3132       && TREE_CODE (expr) == INTEGER_CST
3133       && TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE)
3134     value = non_lvalue (value);
3135
3136   /* Don't let a cast be an lvalue.  */
3137   if (value == expr)
3138     value = non_lvalue (value);
3139
3140   return value;
3141 }
3142
3143 /* Interpret a cast of expression EXPR to type TYPE.  */
3144 tree
3145 c_cast_expr (tree type, tree expr)
3146 {
3147   int saved_wsp = warn_strict_prototypes;
3148
3149   /* This avoids warnings about unprototyped casts on
3150      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3151   if (TREE_CODE (expr) == INTEGER_CST)
3152     warn_strict_prototypes = 0;
3153   type = groktypename (type);
3154   warn_strict_prototypes = saved_wsp;
3155
3156   return build_c_cast (type, expr);
3157 }
3158
3159 \f
3160 /* Build an assignment expression of lvalue LHS from value RHS.
3161    MODIFYCODE is the code for a binary operator that we use
3162    to combine the old value of LHS with RHS to get the new value.
3163    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3164
3165 tree
3166 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3167 {
3168   tree result;
3169   tree newrhs;
3170   tree lhstype = TREE_TYPE (lhs);
3171   tree olhstype = lhstype;
3172
3173   /* Types that aren't fully specified cannot be used in assignments.  */
3174   lhs = require_complete_type (lhs);
3175
3176   /* Avoid duplicate error messages from operands that had errors.  */
3177   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3178     return error_mark_node;
3179
3180   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3181   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3182      whose value is 0 to count as a null pointer constant.  */
3183   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3184     rhs = TREE_OPERAND (rhs, 0);
3185
3186   newrhs = rhs;
3187
3188   /* If a binary op has been requested, combine the old LHS value with the RHS
3189      producing the value we should actually store into the LHS.  */
3190
3191   if (modifycode != NOP_EXPR)
3192     {
3193       lhs = stabilize_reference (lhs);
3194       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3195     }
3196
3197   if (!lvalue_or_else (lhs, "invalid lvalue in assignment"))
3198     return error_mark_node;
3199
3200   /* Warn about storing in something that is `const'.  */
3201
3202   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3203       || ((TREE_CODE (lhstype) == RECORD_TYPE
3204            || TREE_CODE (lhstype) == UNION_TYPE)
3205           && C_TYPE_FIELDS_READONLY (lhstype)))
3206     readonly_error (lhs, "assignment");
3207
3208   /* If storing into a structure or union member,
3209      it has probably been given type `int'.
3210      Compute the type that would go with
3211      the actual amount of storage the member occupies.  */
3212
3213   if (TREE_CODE (lhs) == COMPONENT_REF
3214       && (TREE_CODE (lhstype) == INTEGER_TYPE
3215           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3216           || TREE_CODE (lhstype) == REAL_TYPE
3217           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3218     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3219
3220   /* If storing in a field that is in actuality a short or narrower than one,
3221      we must store in the field in its actual type.  */
3222
3223   if (lhstype != TREE_TYPE (lhs))
3224     {
3225       lhs = copy_node (lhs);
3226       TREE_TYPE (lhs) = lhstype;
3227     }
3228
3229   /* Convert new value to destination type.  */
3230
3231   newrhs = convert_for_assignment (lhstype, newrhs, _("assignment"),
3232                                    NULL_TREE, NULL_TREE, 0);
3233   if (TREE_CODE (newrhs) == ERROR_MARK)
3234     return error_mark_node;
3235
3236   /* Scan operands */
3237
3238   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3239   TREE_SIDE_EFFECTS (result) = 1;
3240
3241   /* If we got the LHS in a different type for storing in,
3242      convert the result back to the nominal type of LHS
3243      so that the value we return always has the same type
3244      as the LHS argument.  */
3245
3246   if (olhstype == TREE_TYPE (result))
3247     return result;
3248   return convert_for_assignment (olhstype, result, _("assignment"),
3249                                  NULL_TREE, NULL_TREE, 0);
3250 }
3251 \f
3252 /* Convert value RHS to type TYPE as preparation for an assignment
3253    to an lvalue of type TYPE.
3254    The real work of conversion is done by `convert'.
3255    The purpose of this function is to generate error messages
3256    for assignments that are not allowed in C.
3257    ERRTYPE is a string to use in error messages:
3258    "assignment", "return", etc.  If it is null, this is parameter passing
3259    for a function call (and different error messages are output).
3260
3261    FUNNAME is the name of the function being called,
3262    as an IDENTIFIER_NODE, or null.
3263    PARMNUM is the number of the argument, for printing in error messages.  */
3264
3265 static tree
3266 convert_for_assignment (tree type, tree rhs, const char *errtype,
3267                         tree fundecl, tree funname, int parmnum)
3268 {
3269   enum tree_code codel = TREE_CODE (type);
3270   tree rhstype;
3271   enum tree_code coder;
3272
3273   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3274   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3275      whose value is 0 to count as a null pointer constant.  */
3276   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3277     rhs = TREE_OPERAND (rhs, 0);
3278
3279   if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
3280       || TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE)
3281     rhs = default_conversion (rhs);
3282   else if (optimize && TREE_CODE (rhs) == VAR_DECL)
3283     rhs = decl_constant_value_for_broken_optimization (rhs);
3284
3285   rhstype = TREE_TYPE (rhs);
3286   coder = TREE_CODE (rhstype);
3287
3288   if (coder == ERROR_MARK)
3289     return error_mark_node;
3290
3291   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3292     {
3293       overflow_warning (rhs);
3294       /* Check for Objective-C protocols.  This will automatically
3295          issue a warning if there are protocol violations.  No need to
3296          use the return value.  */
3297       if (c_dialect_objc ())
3298         objc_comptypes (type, rhstype, 0);
3299       return rhs;
3300     }
3301
3302   if (coder == VOID_TYPE)
3303     {
3304       error ("void value not ignored as it ought to be");
3305       return error_mark_node;
3306     }
3307   /* A type converts to a reference to it.
3308      This code doesn't fully support references, it's just for the
3309      special case of va_start and va_copy.  */
3310   if (codel == REFERENCE_TYPE
3311       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3312     {
3313       if (!lvalue_p (rhs))
3314         {
3315           error ("cannot pass rvalue to reference parameter");
3316           return error_mark_node;
3317         }
3318       if (!c_mark_addressable (rhs))
3319         return error_mark_node;
3320       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3321
3322       /* We already know that these two types are compatible, but they
3323          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3324          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3325          likely to be va_list, a typedef to __builtin_va_list, which
3326          is different enough that it will cause problems later.  */
3327       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3328         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3329
3330       rhs = build1 (NOP_EXPR, type, rhs);
3331       return rhs;
3332     }
3333   /* Some types can interconvert without explicit casts.  */
3334   else if (codel == VECTOR_TYPE
3335            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3336     return convert (type, rhs);
3337   /* Arithmetic types all interconvert, and enum is treated like int.  */
3338   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3339             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3340             || codel == BOOLEAN_TYPE)
3341            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3342                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3343                || coder == BOOLEAN_TYPE))
3344     return convert_and_check (type, rhs);
3345
3346   /* Conversion to a transparent union from its member types.
3347      This applies only to function arguments.  */
3348   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type) && ! errtype)
3349     {
3350       tree memb_types;
3351       tree marginal_memb_type = 0;
3352
3353       for (memb_types = TYPE_FIELDS (type); memb_types;
3354            memb_types = TREE_CHAIN (memb_types))
3355         {
3356           tree memb_type = TREE_TYPE (memb_types);
3357
3358           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3359                          TYPE_MAIN_VARIANT (rhstype)))
3360             break;
3361
3362           if (TREE_CODE (memb_type) != POINTER_TYPE)
3363             continue;
3364
3365           if (coder == POINTER_TYPE)
3366             {
3367               tree ttl = TREE_TYPE (memb_type);
3368               tree ttr = TREE_TYPE (rhstype);
3369
3370               /* Any non-function converts to a [const][volatile] void *
3371                  and vice versa; otherwise, targets must be the same.
3372                  Meanwhile, the lhs target must have all the qualifiers of
3373                  the rhs.  */
3374               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3375                   || comp_target_types (memb_type, rhstype, 0))
3376                 {
3377                   /* If this type won't generate any warnings, use it.  */
3378                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3379                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3380                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3381                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3382                              == TYPE_QUALS (ttr))
3383                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3384                              == TYPE_QUALS (ttl))))
3385                     break;
3386
3387                   /* Keep looking for a better type, but remember this one.  */
3388                   if (! marginal_memb_type)
3389                     marginal_memb_type = memb_type;
3390                 }
3391             }
3392
3393           /* Can convert integer zero to any pointer type.  */
3394           if (integer_zerop (rhs)
3395               || (TREE_CODE (rhs) == NOP_EXPR
3396                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3397             {
3398               rhs = null_pointer_node;
3399               break;
3400             }
3401         }
3402
3403       if (memb_types || marginal_memb_type)
3404         {
3405           if (! memb_types)
3406             {
3407               /* We have only a marginally acceptable member type;
3408                  it needs a warning.  */
3409               tree ttl = TREE_TYPE (marginal_memb_type);
3410               tree ttr = TREE_TYPE (rhstype);
3411
3412               /* Const and volatile mean something different for function
3413                  types, so the usual warnings are not appropriate.  */
3414               if (TREE_CODE (ttr) == FUNCTION_TYPE
3415                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3416                 {
3417                   /* Because const and volatile on functions are
3418                      restrictions that say the function will not do
3419                      certain things, it is okay to use a const or volatile
3420                      function where an ordinary one is wanted, but not
3421                      vice-versa.  */
3422                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3423                     warn_for_assignment ("%s makes qualified function pointer from unqualified",
3424                                          errtype, funname, parmnum);
3425                 }
3426               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3427                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3428                                      errtype, funname,
3429                                      parmnum);
3430             }
3431
3432           if (pedantic && ! DECL_IN_SYSTEM_HEADER (fundecl))
3433             pedwarn ("ISO C prohibits argument conversion to union type");
3434
3435           return build1 (NOP_EXPR, type, rhs);
3436         }
3437     }
3438
3439   /* Conversions among pointers */
3440   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3441            && (coder == codel))
3442     {
3443       tree ttl = TREE_TYPE (type);
3444       tree ttr = TREE_TYPE (rhstype);
3445       bool is_opaque_pointer;
3446       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3447
3448       /* Opaque pointers are treated like void pointers.  */
3449       is_opaque_pointer = (targetm.vector_opaque_p (type)
3450                            || targetm.vector_opaque_p (rhstype))
3451         && TREE_CODE (ttl) == VECTOR_TYPE
3452         && TREE_CODE (ttr) == VECTOR_TYPE;
3453
3454       /* Any non-function converts to a [const][volatile] void *
3455          and vice versa; otherwise, targets must be the same.
3456          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3457       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3458           || (target_cmp = comp_target_types (type, rhstype, 0))
3459           || is_opaque_pointer
3460           || (c_common_unsigned_type (TYPE_MAIN_VARIANT (ttl))
3461               == c_common_unsigned_type (TYPE_MAIN_VARIANT (ttr))))
3462         {
3463           if (pedantic
3464               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3465                   ||
3466                   (VOID_TYPE_P (ttr)
3467                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3468                       which are not ANSI null ptr constants.  */
3469                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3470                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3471             warn_for_assignment ("ISO C forbids %s between function pointer and `void *'",
3472                                  errtype, funname, parmnum);
3473           /* Const and volatile mean something different for function types,
3474              so the usual warnings are not appropriate.  */
3475           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3476                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3477             {
3478               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3479                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3480                                      errtype, funname, parmnum);
3481               /* If this is not a case of ignoring a mismatch in signedness,
3482                  no warning.  */
3483               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3484                        || target_cmp)
3485                 ;
3486               /* If there is a mismatch, do warn.  */
3487               else
3488                 warn_for_assignment ("pointer targets in %s differ in signedness",
3489                                      errtype, funname, parmnum);
3490             }
3491           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3492                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3493             {
3494               /* Because const and volatile on functions are restrictions
3495                  that say the function will not do certain things,
3496                  it is okay to use a const or volatile function
3497                  where an ordinary one is wanted, but not vice-versa.  */
3498               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3499                 warn_for_assignment ("%s makes qualified function pointer from unqualified",
3500                                      errtype, funname, parmnum);
3501             }
3502         }
3503       else
3504         warn_for_assignment ("%s from incompatible pointer type",
3505                              errtype, funname, parmnum);
3506       return convert (type, rhs);
3507     }
3508   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3509     {
3510       error ("invalid use of non-lvalue array");
3511       return error_mark_node;
3512     }
3513   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3514     {
3515       /* An explicit constant 0 can convert to a pointer,
3516          or one that results from arithmetic, even including
3517          a cast to integer type.  */
3518       if (! (TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3519           &&
3520           ! (TREE_CODE (rhs) == NOP_EXPR
3521              && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3522              && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3523              && integer_zerop (TREE_OPERAND (rhs, 0))))
3524           warn_for_assignment ("%s makes pointer from integer without a cast",
3525                                errtype, funname, parmnum);
3526
3527       return convert (type, rhs);
3528     }
3529   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3530     {
3531       warn_for_assignment ("%s makes integer from pointer without a cast",
3532                            errtype, funname, parmnum);
3533       return convert (type, rhs);
3534     }
3535   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3536     return convert (type, rhs);
3537
3538   if (!errtype)
3539     {
3540       if (funname)
3541         {
3542           tree selector = objc_message_selector ();
3543
3544           if (selector && parmnum > 2)
3545             error ("incompatible type for argument %d of `%s'",
3546                    parmnum - 2, IDENTIFIER_POINTER (selector));
3547           else
3548             error ("incompatible type for argument %d of `%s'",
3549                    parmnum, IDENTIFIER_POINTER (funname));
3550         }
3551       else
3552         error ("incompatible type for argument %d of indirect function call",
3553                parmnum);
3554     }
3555   else
3556     error ("incompatible types in %s", errtype);
3557
3558   return error_mark_node;
3559 }
3560
3561 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3562    is used for error and waring reporting and indicates which argument
3563    is being processed.  */
3564
3565 tree
3566 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3567 {
3568   tree ret, type;
3569
3570   /* If FN was prototyped, the value has been converted already
3571      in convert_arguments.  */
3572   if (! value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3573     return value;
3574
3575   type = TREE_TYPE (parm);
3576   ret = convert_for_assignment (type, value,
3577                                 (char *) 0 /* arg passing  */, fn,
3578                                 DECL_NAME (fn), argnum);
3579   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3580       && INTEGRAL_TYPE_P (type)
3581       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3582     ret = default_conversion (ret);
3583   return ret;
3584 }
3585
3586 /* Print a warning using MSGID.
3587    It gets OPNAME as its one parameter.
3588    if OPNAME is null and ARGNUM is 0, it is replaced by "passing arg of `FUNCTION'".
3589    Otherwise if OPNAME is null, it is replaced by "passing arg ARGNUM of `FUNCTION'".
3590    FUNCTION and ARGNUM are handled specially if we are building an
3591    Objective-C selector.  */
3592
3593 static void
3594 warn_for_assignment (const char *msgid, const char *opname, tree function,
3595                      int argnum)
3596 {
3597   if (opname == 0)
3598     {
3599       tree selector = objc_message_selector ();
3600       char * new_opname;
3601
3602       if (selector && argnum > 2)
3603         {
3604           function = selector;
3605           argnum -= 2;
3606         }
3607       if (argnum == 0)
3608         {
3609           if (function)
3610             {
3611               /* Function name is known; supply it.  */
3612               const char *const argstring = _("passing arg of `%s'");
3613               new_opname = (char *) alloca (IDENTIFIER_LENGTH (function)
3614                                    + strlen (argstring) + 1 + 1);
3615               sprintf (new_opname, argstring,
3616                        IDENTIFIER_POINTER (function));
3617             }
3618           else
3619             {
3620               /* Function name unknown (call through ptr).  */
3621               const char *const argnofun = _("passing arg of pointer to function");
3622               new_opname = (char *) alloca (strlen (argnofun) + 1 + 1);
3623               sprintf (new_opname, argnofun);
3624             }
3625         }
3626       else if (function)
3627         {
3628           /* Function name is known; supply it.  */
3629           const char *const argstring = _("passing arg %d of `%s'");
3630           new_opname = (char *) alloca (IDENTIFIER_LENGTH (function)
3631                                + strlen (argstring) + 1 + 25 /*%d*/ + 1);
3632           sprintf (new_opname, argstring, argnum,
3633                    IDENTIFIER_POINTER (function));
3634         }
3635       else
3636         {
3637           /* Function name unknown (call through ptr); just give arg number.  */
3638           const char *const argnofun = _("passing arg %d of pointer to function");
3639           new_opname = (char *) alloca (strlen (argnofun) + 1 + 25 /*%d*/ + 1);
3640           sprintf (new_opname, argnofun, argnum);
3641         }
3642       opname = new_opname;
3643     }
3644   pedwarn (msgid, opname);
3645 }
3646 \f
3647 /* If VALUE is a compound expr all of whose expressions are constant, then
3648    return its value.  Otherwise, return error_mark_node.
3649
3650    This is for handling COMPOUND_EXPRs as initializer elements
3651    which is allowed with a warning when -pedantic is specified.  */
3652
3653 static tree
3654 valid_compound_expr_initializer (tree value, tree endtype)
3655 {
3656   if (TREE_CODE (value) == COMPOUND_EXPR)
3657     {
3658       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3659           == error_mark_node)
3660         return error_mark_node;
3661       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3662                                               endtype);
3663     }
3664   else if (! TREE_CONSTANT (value)
3665            && ! initializer_constant_valid_p (value, endtype))
3666     return error_mark_node;
3667   else
3668     return value;
3669 }
3670 \f
3671 /* Perform appropriate conversions on the initial value of a variable,
3672    store it in the declaration DECL,
3673    and print any error messages that are appropriate.
3674    If the init is invalid, store an ERROR_MARK.  */
3675
3676 void
3677 store_init_value (tree decl, tree init)
3678 {
3679   tree value, type;
3680
3681   /* If variable's type was invalidly declared, just ignore it.  */
3682
3683   type = TREE_TYPE (decl);
3684   if (TREE_CODE (type) == ERROR_MARK)
3685     return;
3686
3687   /* Digest the specified initializer into an expression.  */
3688
3689   value = digest_init (type, init, true, TREE_STATIC (decl));
3690
3691   /* Store the expression if valid; else report error.  */
3692
3693   if (warn_traditional && !in_system_header
3694       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && ! TREE_STATIC (decl))
3695     warning ("traditional C rejects automatic aggregate initialization");
3696
3697   DECL_INITIAL (decl) = value;
3698
3699   /* ANSI wants warnings about out-of-range constant initializers.  */
3700   STRIP_TYPE_NOPS (value);
3701   constant_expression_warning (value);
3702
3703   /* Check if we need to set array size from compound literal size.  */
3704   if (TREE_CODE (type) == ARRAY_TYPE
3705       && TYPE_DOMAIN (type) == 0
3706       && value != error_mark_node)
3707     {
3708       tree inside_init = init;
3709
3710       if (TREE_CODE (init) == NON_LVALUE_EXPR)
3711         inside_init = TREE_OPERAND (init, 0);
3712       inside_init = fold (inside_init);
3713
3714       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
3715         {
3716           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
3717
3718           if (TYPE_DOMAIN (TREE_TYPE (decl)))
3719             {
3720               /* For int foo[] = (int [3]){1}; we need to set array size
3721                  now since later on array initializer will be just the
3722                  brace enclosed list of the compound literal.  */
3723               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
3724               layout_type (type);
3725               layout_decl (decl, 0);
3726             }
3727         }
3728     }
3729 }
3730 \f
3731 /* Methods for storing and printing names for error messages.  */
3732
3733 /* Implement a spelling stack that allows components of a name to be pushed
3734    and popped.  Each element on the stack is this structure.  */
3735
3736 struct spelling
3737 {
3738   int kind;
3739   union
3740     {
3741       int i;
3742       const char *s;
3743     } u;
3744 };
3745
3746 #define SPELLING_STRING 1
3747 #define SPELLING_MEMBER 2
3748 #define SPELLING_BOUNDS 3
3749
3750 static struct spelling *spelling;       /* Next stack element (unused).  */
3751 static struct spelling *spelling_base;  /* Spelling stack base.  */
3752 static int spelling_size;               /* Size of the spelling stack.  */
3753
3754 /* Macros to save and restore the spelling stack around push_... functions.
3755    Alternative to SAVE_SPELLING_STACK.  */
3756
3757 #define SPELLING_DEPTH() (spelling - spelling_base)
3758 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
3759
3760 /* Push an element on the spelling stack with type KIND and assign VALUE
3761    to MEMBER.  */
3762
3763 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
3764 {                                                                       \
3765   int depth = SPELLING_DEPTH ();                                        \
3766                                                                         \
3767   if (depth >= spelling_size)                                           \
3768     {                                                                   \
3769       spelling_size += 10;                                              \
3770       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
3771                                   spelling_size);                       \
3772       RESTORE_SPELLING_DEPTH (depth);                                   \
3773     }                                                                   \
3774                                                                         \
3775   spelling->kind = (KIND);                                              \
3776   spelling->MEMBER = (VALUE);                                           \
3777   spelling++;                                                           \
3778 }
3779
3780 /* Push STRING on the stack.  Printed literally.  */
3781
3782 static void
3783 push_string (const char *string)
3784 {
3785   PUSH_SPELLING (SPELLING_STRING, string, u.s);
3786 }
3787
3788 /* Push a member name on the stack.  Printed as '.' STRING.  */
3789
3790 static void
3791 push_member_name (tree decl)
3792 {
3793   const char *const string
3794     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
3795   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
3796 }
3797
3798 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
3799
3800 static void
3801 push_array_bounds (int bounds)
3802 {
3803   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
3804 }
3805
3806 /* Compute the maximum size in bytes of the printed spelling.  */
3807
3808 static int
3809 spelling_length (void)
3810 {
3811   int size = 0;
3812   struct spelling *p;
3813
3814   for (p = spelling_base; p < spelling; p++)
3815     {
3816       if (p->kind == SPELLING_BOUNDS)
3817         size += 25;
3818       else
3819         size += strlen (p->u.s) + 1;
3820     }
3821
3822   return size;
3823 }
3824
3825 /* Print the spelling to BUFFER and return it.  */
3826
3827 static char *
3828 print_spelling (char *buffer)
3829 {
3830   char *d = buffer;
3831   struct spelling *p;
3832
3833   for (p = spelling_base; p < spelling; p++)
3834     if (p->kind == SPELLING_BOUNDS)
3835       {
3836         sprintf (d, "[%d]", p->u.i);
3837         d += strlen (d);
3838       }
3839     else
3840       {
3841         const char *s;
3842         if (p->kind == SPELLING_MEMBER)
3843           *d++ = '.';
3844         for (s = p->u.s; (*d = *s++); d++)
3845           ;
3846       }
3847   *d++ = '\0';
3848   return buffer;
3849 }
3850
3851 /* Issue an error message for a bad initializer component.
3852    MSGID identifies the message.
3853    The component name is taken from the spelling stack.  */
3854
3855 void
3856 error_init (const char *msgid)
3857 {
3858   char *ofwhat;
3859
3860   error ("%s", _(msgid));
3861   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3862   if (*ofwhat)
3863     error ("(near initialization for `%s')", ofwhat);
3864 }
3865
3866 /* Issue a pedantic warning for a bad initializer component.
3867    MSGID identifies the message.
3868    The component name is taken from the spelling stack.  */
3869
3870 void
3871 pedwarn_init (const char *msgid)
3872 {
3873   char *ofwhat;
3874
3875   pedwarn ("%s", _(msgid));
3876   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3877   if (*ofwhat)
3878     pedwarn ("(near initialization for `%s')", ofwhat);
3879 }
3880
3881 /* Issue a warning for a bad initializer component.
3882    MSGID identifies the message.
3883    The component name is taken from the spelling stack.  */
3884
3885 static void
3886 warning_init (const char *msgid)
3887 {
3888   char *ofwhat;
3889
3890   warning ("%s", _(msgid));
3891   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
3892   if (*ofwhat)
3893     warning ("(near initialization for `%s')", ofwhat);
3894 }
3895 \f
3896 /* If TYPE is an array type and EXPR is a parenthesized string
3897    constant, warn if pedantic that EXPR is being used to initialize an
3898    object of type TYPE.  */
3899
3900 void
3901 maybe_warn_string_init (tree type, struct c_expr expr)
3902 {
3903   if (pedantic
3904       && TREE_CODE (type) == ARRAY_TYPE
3905       && TREE_CODE (expr.value) == STRING_CST
3906       && expr.original_code != STRING_CST)
3907     pedwarn_init ("array initialized from parenthesized string constant");
3908 }
3909
3910 /* Digest the parser output INIT as an initializer for type TYPE.
3911    Return a C expression of type TYPE to represent the initial value.
3912
3913    If INIT is a string constant, STRICT_STRING is true if it is
3914    unparenthesized or we should not warn here for it being parenthesized.
3915    For other types of INIT, STRICT_STRING is not used.
3916
3917    REQUIRE_CONSTANT requests an error if non-constant initializers or
3918    elements are seen.  */
3919
3920 static tree
3921 digest_init (tree type, tree init, bool strict_string, int require_constant)
3922 {
3923   enum tree_code code = TREE_CODE (type);
3924   tree inside_init = init;
3925
3926   if (type == error_mark_node
3927       || init == error_mark_node
3928       || TREE_TYPE (init) == error_mark_node)
3929     return error_mark_node;
3930
3931   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3932   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3933      whose value is 0 to count as a null pointer constant.  */
3934   if (TREE_CODE (init) == NON_LVALUE_EXPR)
3935     inside_init = TREE_OPERAND (init, 0);
3936
3937   inside_init = fold (inside_init);
3938
3939   /* Initialization of an array of chars from a string constant
3940      optionally enclosed in braces.  */
3941
3942   if (code == ARRAY_TYPE && inside_init
3943       && TREE_CODE (inside_init) == STRING_CST)
3944     {
3945       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
3946       /* Note that an array could be both an array of character type
3947          and an array of wchar_t if wchar_t is signed char or unsigned
3948          char.  */
3949       bool char_array = (typ1 == char_type_node
3950                          || typ1 == signed_char_type_node
3951                          || typ1 == unsigned_char_type_node);
3952       bool wchar_array = !!comptypes (typ1, wchar_type_node);
3953       if (char_array || wchar_array)
3954         {
3955           struct c_expr expr;
3956           bool char_string;
3957           expr.value = inside_init;
3958           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
3959           maybe_warn_string_init (type, expr);
3960
3961           char_string
3962             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3963                == char_type_node);
3964
3965           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
3966                          TYPE_MAIN_VARIANT (type)))
3967             return inside_init;
3968
3969           if (!wchar_array && !char_string)
3970             {
3971               error_init ("char-array initialized from wide string");
3972               return error_mark_node;
3973             }
3974           if (char_string && !char_array)
3975             {
3976               error_init ("wchar_t-array initialized from non-wide string");
3977               return error_mark_node;
3978             }
3979
3980           TREE_TYPE (inside_init) = type;
3981           if (TYPE_DOMAIN (type) != 0
3982               && TYPE_SIZE (type) != 0
3983               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
3984               /* Subtract 1 (or sizeof (wchar_t))
3985                  because it's ok to ignore the terminating null char
3986                  that is counted in the length of the constant.  */
3987               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
3988                                        TREE_STRING_LENGTH (inside_init)
3989                                        - ((TYPE_PRECISION (typ1)
3990                                            != TYPE_PRECISION (char_type_node))
3991                                           ? (TYPE_PRECISION (wchar_type_node)
3992                                              / BITS_PER_UNIT)
3993                                           : 1)))
3994             pedwarn_init ("initializer-string for array of chars is too long");
3995
3996           return inside_init;
3997         }
3998       else if (INTEGRAL_TYPE_P (typ1))
3999         {
4000           error_init ("array of inappropriate type initialized "
4001                       "from string constant");
4002           return error_mark_node;
4003         }
4004     }
4005
4006   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4007      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4008      below and handle as a constructor.  */
4009     if (code == VECTOR_TYPE
4010         && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4011         && TREE_CONSTANT (inside_init))
4012       {
4013         if (TREE_CODE (inside_init) == VECTOR_CST
4014             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4015                           TYPE_MAIN_VARIANT (type)))
4016           return inside_init;
4017         else
4018           return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4019       }
4020
4021   /* Any type can be initialized
4022      from an expression of the same type, optionally with braces.  */
4023
4024   if (inside_init && TREE_TYPE (inside_init) != 0
4025       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4026                      TYPE_MAIN_VARIANT (type))
4027           || (code == ARRAY_TYPE
4028               && comptypes (TREE_TYPE (inside_init), type))
4029           || (code == VECTOR_TYPE
4030               && comptypes (TREE_TYPE (inside_init), type))
4031           || (code == POINTER_TYPE
4032               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4033               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4034                             TREE_TYPE (type)))
4035           || (code == POINTER_TYPE
4036               && TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE
4037               && comptypes (TREE_TYPE (inside_init),
4038                             TREE_TYPE (type)))))
4039     {
4040       if (code == POINTER_TYPE)
4041         {
4042           inside_init = default_function_array_conversion (inside_init);
4043
4044           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4045             {
4046               error_init ("invalid use of non-lvalue array");
4047               return error_mark_node;
4048             }
4049          }
4050
4051       if (code == VECTOR_TYPE)
4052         /* Although the types are compatible, we may require a
4053            conversion.  */
4054         inside_init = convert (type, inside_init);
4055
4056       if (require_constant && !flag_isoc99
4057           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4058         {
4059           /* As an extension, allow initializing objects with static storage
4060              duration with compound literals (which are then treated just as
4061              the brace enclosed list they contain).  */
4062           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4063           inside_init = DECL_INITIAL (decl);
4064         }
4065
4066       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4067           && TREE_CODE (inside_init) != CONSTRUCTOR)
4068         {
4069           error_init ("array initialized from non-constant array expression");
4070           return error_mark_node;
4071         }
4072
4073       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4074         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4075
4076       /* Compound expressions can only occur here if -pedantic or
4077          -pedantic-errors is specified.  In the later case, we always want
4078          an error.  In the former case, we simply want a warning.  */
4079       if (require_constant && pedantic
4080           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4081         {
4082           inside_init
4083             = valid_compound_expr_initializer (inside_init,
4084                                                TREE_TYPE (inside_init));
4085           if (inside_init == error_mark_node)
4086             error_init ("initializer element is not constant");
4087           else
4088             pedwarn_init ("initializer element is not constant");
4089           if (flag_pedantic_errors)
4090             inside_init = error_mark_node;
4091         }
4092       else if (require_constant
4093                && (!TREE_CONSTANT (inside_init)
4094                    /* This test catches things like `7 / 0' which
4095                       result in an expression for which TREE_CONSTANT
4096                       is true, but which is not actually something
4097                       that is a legal constant.  We really should not
4098                       be using this function, because it is a part of
4099                       the back-end.  Instead, the expression should
4100                       already have been turned into ERROR_MARK_NODE.  */
4101                    || !initializer_constant_valid_p (inside_init,
4102                                                      TREE_TYPE (inside_init))))
4103         {
4104           error_init ("initializer element is not constant");
4105           inside_init = error_mark_node;
4106         }
4107
4108       return inside_init;
4109     }
4110
4111   /* Handle scalar types, including conversions.  */
4112
4113   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4114       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4115       || code == VECTOR_TYPE)
4116     {
4117       /* Note that convert_for_assignment calls default_conversion
4118          for arrays and functions.  We must not call it in the
4119          case where inside_init is a null pointer constant.  */
4120       inside_init
4121         = convert_for_assignment (type, init, _("initialization"),
4122                                   NULL_TREE, NULL_TREE, 0);
4123
4124       if (require_constant && ! TREE_CONSTANT (inside_init))
4125         {
4126           error_init ("initializer element is not constant");
4127           inside_init = error_mark_node;
4128         }
4129       else if (require_constant
4130                && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
4131         {
4132           error_init ("initializer element is not computable at load time");
4133           inside_init = error_mark_node;
4134         }
4135
4136       return inside_init;
4137     }
4138
4139   /* Come here only for records and arrays.  */
4140
4141   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4142     {
4143       error_init ("variable-sized object may not be initialized");
4144       return error_mark_node;
4145     }
4146
4147   error_init ("invalid initializer");
4148   return error_mark_node;
4149 }
4150 \f
4151 /* Handle initializers that use braces.  */
4152
4153 /* Type of object we are accumulating a constructor for.
4154    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4155 static tree constructor_type;
4156
4157 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4158    left to fill.  */
4159 static tree constructor_fields;
4160
4161 /* For an ARRAY_TYPE, this is the specified index
4162    at which to store the next element we get.  */
4163 static tree constructor_index;
4164
4165 /* For an ARRAY_TYPE, this is the maximum index.  */
4166 static tree constructor_max_index;
4167
4168 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4169 static tree constructor_unfilled_fields;
4170
4171 /* For an ARRAY_TYPE, this is the index of the first element
4172    not yet written out.  */
4173 static tree constructor_unfilled_index;
4174
4175 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4176    This is so we can generate gaps between fields, when appropriate.  */
4177 static tree constructor_bit_index;
4178
4179 /* If we are saving up the elements rather than allocating them,
4180    this is the list of elements so far (in reverse order,
4181    most recent first).  */
4182 static tree constructor_elements;
4183
4184 /* 1 if constructor should be incrementally stored into a constructor chain,
4185    0 if all the elements should be kept in AVL tree.  */
4186 static int constructor_incremental;
4187
4188 /* 1 if so far this constructor's elements are all compile-time constants.  */
4189 static int constructor_constant;
4190
4191 /* 1 if so far this constructor's elements are all valid address constants.  */
4192 static int constructor_simple;
4193
4194 /* 1 if this constructor is erroneous so far.  */
4195 static int constructor_erroneous;
4196
4197 /* Structure for managing pending initializer elements, organized as an
4198    AVL tree.  */
4199
4200 struct init_node
4201 {
4202   struct init_node *left, *right;
4203   struct init_node *parent;
4204   int balance;
4205   tree purpose;
4206   tree value;
4207 };
4208
4209 /* Tree of pending elements at this constructor level.
4210    These are elements encountered out of order
4211    which belong at places we haven't reached yet in actually
4212    writing the output.
4213    Will never hold tree nodes across GC runs.  */
4214 static struct init_node *constructor_pending_elts;
4215
4216 /* The SPELLING_DEPTH of this constructor.  */
4217 static int constructor_depth;
4218
4219 /* 0 if implicitly pushing constructor levels is allowed.  */
4220 int constructor_no_implicit = 0; /* 0 for C; 1 for some other languages.  */
4221
4222 /* DECL node for which an initializer is being read.
4223    0 means we are reading a constructor expression
4224    such as (struct foo) {...}.  */
4225 static tree constructor_decl;
4226
4227 /* start_init saves the ASMSPEC arg here for really_start_incremental_init.  */
4228 static const char *constructor_asmspec;
4229
4230 /* Nonzero if this is an initializer for a top-level decl.  */
4231 static int constructor_top_level;
4232
4233 /* Nonzero if there were any member designators in this initializer.  */
4234 static int constructor_designated;
4235
4236 /* Nesting depth of designator list.  */
4237 static int designator_depth;
4238
4239 /* Nonzero if there were diagnosed errors in this designator list.  */
4240 static int designator_errorneous;
4241
4242 \f
4243 /* This stack has a level for each implicit or explicit level of
4244    structuring in the initializer, including the outermost one.  It
4245    saves the values of most of the variables above.  */
4246
4247 struct constructor_range_stack;
4248
4249 struct constructor_stack
4250 {
4251   struct constructor_stack *next;
4252   tree type;
4253   tree fields;
4254   tree index;
4255   tree max_index;
4256   tree unfilled_index;
4257   tree unfilled_fields;
4258   tree bit_index;
4259   tree elements;
4260   struct init_node *pending_elts;
4261   int offset;
4262   int depth;
4263   /* If value nonzero, this value should replace the entire
4264      constructor at this level.  */
4265   struct c_expr replacement_value;
4266   struct constructor_range_stack *range_stack;
4267   char constant;
4268   char simple;
4269   char implicit;
4270   char erroneous;
4271   char outer;
4272   char incremental;
4273   char designated;
4274 };
4275
4276 struct constructor_stack *constructor_stack;
4277
4278 /* This stack represents designators from some range designator up to
4279    the last designator in the list.  */
4280
4281 struct constructor_range_stack
4282 {
4283   struct constructor_range_stack *next, *prev;
4284   struct constructor_stack *stack;
4285   tree range_start;
4286   tree index;
4287   tree range_end;
4288   tree fields;
4289 };
4290
4291 struct constructor_range_stack *constructor_range_stack;
4292
4293 /* This stack records separate initializers that are nested.
4294    Nested initializers can't happen in ANSI C, but GNU C allows them
4295    in cases like { ... (struct foo) { ... } ... }.  */
4296
4297 struct initializer_stack
4298 {
4299   struct initializer_stack *next;
4300   tree decl;
4301   const char *asmspec;
4302   struct constructor_stack *constructor_stack;
4303   struct constructor_range_stack *constructor_range_stack;
4304   tree elements;
4305   struct spelling *spelling;
4306   struct spelling *spelling_base;
4307   int spelling_size;
4308   char top_level;
4309   char require_constant_value;
4310   char require_constant_elements;
4311 };
4312
4313 struct initializer_stack *initializer_stack;
4314 \f
4315 /* Prepare to parse and output the initializer for variable DECL.  */
4316
4317 void
4318 start_init (tree decl, tree asmspec_tree, int top_level)
4319 {
4320   const char *locus;
4321   struct initializer_stack *p = XNEW (struct initializer_stack);
4322   const char *asmspec = 0;
4323
4324   if (asmspec_tree)
4325     asmspec = TREE_STRING_POINTER (asmspec_tree);
4326
4327   p->decl = constructor_decl;
4328   p->asmspec = constructor_asmspec;
4329   p->require_constant_value = require_constant_value;
4330   p->require_constant_elements = require_constant_elements;
4331   p->constructor_stack = constructor_stack;
4332   p->constructor_range_stack = constructor_range_stack;
4333   p->elements = constructor_elements;
4334   p->spelling = spelling;
4335   p->spelling_base = spelling_base;
4336   p->spelling_size = spelling_size;
4337   p->top_level = constructor_top_level;
4338   p->next = initializer_stack;
4339   initializer_stack = p;
4340
4341   constructor_decl = decl;
4342   constructor_asmspec = asmspec;
4343   constructor_designated = 0;
4344   constructor_top_level = top_level;
4345
4346   if (decl != 0)
4347     {
4348       require_constant_value = TREE_STATIC (decl);
4349       require_constant_elements
4350         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4351            /* For a scalar, you can always use any value to initialize,
4352               even within braces.  */
4353            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4354                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4355                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4356                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4357       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4358     }
4359   else
4360     {
4361       require_constant_value = 0;
4362       require_constant_elements = 0;
4363       locus = "(anonymous)";
4364     }
4365
4366   constructor_stack = 0;
4367   constructor_range_stack = 0;
4368
4369   missing_braces_mentioned = 0;
4370
4371   spelling_base = 0;
4372   spelling_size = 0;
4373   RESTORE_SPELLING_DEPTH (0);
4374
4375   if (locus)
4376     push_string (locus);
4377 }
4378
4379 void
4380 finish_init (void)
4381 {
4382   struct initializer_stack *p = initializer_stack;
4383
4384   /* Free the whole constructor stack of this initializer.  */
4385   while (constructor_stack)
4386     {
4387       struct constructor_stack *q = constructor_stack;
4388       constructor_stack = q->next;
4389       free (q);
4390     }
4391
4392   if (constructor_range_stack)
4393     abort ();
4394
4395   /* Pop back to the data of the outer initializer (if any).  */
4396   free (spelling_base);
4397
4398   constructor_decl = p->decl;
4399   constructor_asmspec = p->asmspec;
4400   require_constant_value = p->require_constant_value;
4401   require_constant_elements = p->require_constant_elements;
4402   constructor_stack = p->constructor_stack;
4403   constructor_range_stack = p->constructor_range_stack;
4404   constructor_elements = p->elements;
4405   spelling = p->spelling;
4406   spelling_base = p->spelling_base;
4407   spelling_size = p->spelling_size;
4408   constructor_top_level = p->top_level;
4409   initializer_stack = p->next;
4410   free (p);
4411 }
4412 \f
4413 /* Call here when we see the initializer is surrounded by braces.
4414    This is instead of a call to push_init_level;
4415    it is matched by a call to pop_init_level.
4416
4417    TYPE is the type to initialize, for a constructor expression.
4418    For an initializer for a decl, TYPE is zero.  */
4419
4420 void
4421 really_start_incremental_init (tree type)
4422 {
4423   struct constructor_stack *p = XNEW (struct constructor_stack);
4424
4425   if (type == 0)
4426     type = TREE_TYPE (constructor_decl);
4427
4428   if (targetm.vector_opaque_p (type))
4429     error ("opaque vector types cannot be initialized");
4430
4431   p->type = constructor_type;
4432   p->fields = constructor_fields;
4433   p->index = constructor_index;
4434   p->max_index = constructor_max_index;
4435   p->unfilled_index = constructor_unfilled_index;
4436   p->unfilled_fields = constructor_unfilled_fields;
4437   p->bit_index = constructor_bit_index;
4438   p->elements = constructor_elements;
4439   p->constant = constructor_constant;
4440   p->simple = constructor_simple;
4441   p->erroneous = constructor_erroneous;
4442   p->pending_elts = constructor_pending_elts;
4443   p->depth = constructor_depth;
4444   p->replacement_value.value = 0;
4445   p->replacement_value.original_code = ERROR_MARK;
4446   p->implicit = 0;
4447   p->range_stack = 0;
4448   p->outer = 0;
4449   p->incremental = constructor_incremental;
4450   p->designated = constructor_designated;
4451   p->next = 0;
4452   constructor_stack = p;
4453
4454   constructor_constant = 1;
4455   constructor_simple = 1;
4456   constructor_depth = SPELLING_DEPTH ();
4457   constructor_elements = 0;
4458   constructor_pending_elts = 0;
4459   constructor_type = type;
4460   constructor_incremental = 1;
4461   constructor_designated = 0;
4462   designator_depth = 0;
4463   designator_errorneous = 0;
4464
4465   if (TREE_CODE (constructor_type) == RECORD_TYPE
4466       || TREE_CODE (constructor_type) == UNION_TYPE)
4467     {
4468       constructor_fields = TYPE_FIELDS (constructor_type);
4469       /* Skip any nameless bit fields at the beginning.  */
4470       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4471              && DECL_NAME (constructor_fields) == 0)
4472         constructor_fields = TREE_CHAIN (constructor_fields);
4473
4474       constructor_unfilled_fields = constructor_fields;
4475       constructor_bit_index = bitsize_zero_node;
4476     }
4477   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4478     {
4479       if (TYPE_DOMAIN (constructor_type))
4480         {
4481           constructor_max_index
4482             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4483
4484           /* Detect non-empty initializations of zero-length arrays.  */
4485           if (constructor_max_index == NULL_TREE
4486               && TYPE_SIZE (constructor_type))
4487             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4488
4489           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4490              to initialize VLAs will cause a proper error; avoid tree
4491              checking errors as well by setting a safe value.  */
4492           if (constructor_max_index
4493               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4494             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4495
4496           constructor_index
4497             = convert (bitsizetype,
4498                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4499         }
4500       else
4501         constructor_index = bitsize_zero_node;
4502
4503       constructor_unfilled_index = constructor_index;
4504     }
4505   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4506     {
4507       /* Vectors are like simple fixed-size arrays.  */
4508       constructor_max_index =
4509         build_int_cst (NULL_TREE,
4510                        TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4511       constructor_index = convert (bitsizetype, bitsize_zero_node);
4512       constructor_unfilled_index = constructor_index;
4513     }
4514   else
4515     {
4516       /* Handle the case of int x = {5}; */
4517       constructor_fields = constructor_type;
4518       constructor_unfilled_fields = constructor_type;
4519     }
4520 }
4521 \f
4522 /* Push down into a subobject, for initialization.
4523    If this is for an explicit set of braces, IMPLICIT is 0.
4524    If it is because the next element belongs at a lower level,
4525    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4526
4527 void
4528 push_init_level (int implicit)
4529 {
4530   struct constructor_stack *p;
4531   tree value = NULL_TREE;
4532
4533   /* If we've exhausted any levels that didn't have braces,
4534      pop them now.  */
4535   while (constructor_stack->implicit)
4536     {
4537       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4538            || TREE_CODE (constructor_type) == UNION_TYPE)
4539           && constructor_fields == 0)
4540         process_init_element (pop_init_level (1));
4541       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4542                && constructor_max_index
4543                && tree_int_cst_lt (constructor_max_index, constructor_index))
4544         process_init_element (pop_init_level (1));
4545       else
4546         break;
4547     }
4548
4549   /* Unless this is an explicit brace, we need to preserve previous
4550      content if any.  */
4551   if (implicit)
4552     {
4553       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4554            || TREE_CODE (constructor_type) == UNION_TYPE)
4555           && constructor_fields)
4556         value = find_init_member (constructor_fields);
4557       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4558         value = find_init_member (constructor_index);
4559     }
4560
4561   p = XNEW (struct constructor_stack);
4562   p->type = constructor_type;
4563   p->fields = constructor_fields;
4564   p->index = constructor_index;
4565   p->max_index = constructor_max_index;
4566   p->unfilled_index = constructor_unfilled_index;
4567   p->unfilled_fields = constructor_unfilled_fields;
4568   p->bit_index = constructor_bit_index;
4569   p->elements = constructor_elements;
4570   p->constant = constructor_constant;
4571   p->simple = constructor_simple;
4572   p->erroneous = constructor_erroneous;
4573   p->pending_elts = constructor_pending_elts;
4574   p->depth = constructor_depth;
4575   p->replacement_value.value = 0;
4576   p->replacement_value.original_code = ERROR_MARK;
4577   p->implicit = implicit;
4578   p->outer = 0;
4579   p->incremental = constructor_incremental;
4580   p->designated = constructor_designated;
4581   p->next = constructor_stack;
4582   p->range_stack = 0;
4583   constructor_stack = p;
4584
4585   constructor_constant = 1;
4586   constructor_simple = 1;
4587   constructor_depth = SPELLING_DEPTH ();
4588   constructor_elements = 0;
4589   constructor_incremental = 1;
4590   constructor_designated = 0;
4591   constructor_pending_elts = 0;
4592   if (!implicit)
4593     {
4594       p->range_stack = constructor_range_stack;
4595       constructor_range_stack = 0;
4596       designator_depth = 0;
4597       designator_errorneous = 0;
4598     }
4599
4600   /* Don't die if an entire brace-pair level is superfluous
4601      in the containing level.  */
4602   if (constructor_type == 0)
4603     ;
4604   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4605            || TREE_CODE (constructor_type) == UNION_TYPE)
4606     {
4607       /* Don't die if there are extra init elts at the end.  */
4608       if (constructor_fields == 0)
4609         constructor_type = 0;
4610       else
4611         {
4612           constructor_type = TREE_TYPE (constructor_fields);
4613           push_member_name (constructor_fields);
4614           constructor_depth++;
4615         }
4616     }
4617   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4618     {
4619       constructor_type = TREE_TYPE (constructor_type);
4620       push_array_bounds (tree_low_cst (constructor_index, 0));
4621       constructor_depth++;
4622     }
4623
4624   if (constructor_type == 0)
4625     {
4626       error_init ("extra brace group at end of initializer");
4627       constructor_fields = 0;
4628       constructor_unfilled_fields = 0;
4629       return;
4630     }
4631
4632   if (value && TREE_CODE (value) == CONSTRUCTOR)
4633     {
4634       constructor_constant = TREE_CONSTANT (value);
4635       constructor_simple = TREE_STATIC (value);
4636       constructor_elements = CONSTRUCTOR_ELTS (value);
4637       if (constructor_elements
4638           && (TREE_CODE (constructor_type) == RECORD_TYPE
4639               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4640         set_nonincremental_init ();
4641     }
4642
4643   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4644     {
4645       missing_braces_mentioned = 1;
4646       warning_init ("missing braces around initializer");
4647     }
4648
4649   if (TREE_CODE (constructor_type) == RECORD_TYPE
4650            || TREE_CODE (constructor_type) == UNION_TYPE)
4651     {
4652       constructor_fields = TYPE_FIELDS (constructor_type);
4653       /* Skip any nameless bit fields at the beginning.  */
4654       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4655              && DECL_NAME (constructor_fields) == 0)
4656         constructor_fields = TREE_CHAIN (constructor_fields);
4657
4658       constructor_unfilled_fields = constructor_fields;
4659       constructor_bit_index = bitsize_zero_node;
4660     }
4661   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4662     {
4663       /* Vectors are like simple fixed-size arrays.  */
4664       constructor_max_index =
4665         build_int_cst (NULL_TREE,
4666                        TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4667       constructor_index = convert (bitsizetype, integer_zero_node);
4668       constructor_unfilled_index = constructor_index;
4669     }
4670   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4671     {
4672       if (TYPE_DOMAIN (constructor_type))
4673         {
4674           constructor_max_index
4675             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4676
4677           /* Detect non-empty initializations of zero-length arrays.  */
4678           if (constructor_max_index == NULL_TREE
4679               && TYPE_SIZE (constructor_type))
4680             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4681
4682           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4683              to initialize VLAs will cause a proper error; avoid tree
4684              checking errors as well by setting a safe value.  */
4685           if (constructor_max_index
4686               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4687             constructor_max_index = build_int_cst (NULL_TREE, -1, -1);
4688
4689           constructor_index
4690             = convert (bitsizetype,
4691                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4692         }
4693       else
4694         constructor_index = bitsize_zero_node;
4695
4696       constructor_unfilled_index = constructor_index;
4697       if (value && TREE_CODE (value) == STRING_CST)
4698         {
4699           /* We need to split the char/wchar array into individual
4700              characters, so that we don't have to special case it
4701              everywhere.  */
4702           set_nonincremental_init_from_string (value);
4703         }
4704     }
4705   else
4706     {
4707       warning_init ("braces around scalar initializer");
4708       constructor_fields = constructor_type;
4709       constructor_unfilled_fields = constructor_type;
4710     }
4711 }
4712
4713 /* At the end of an implicit or explicit brace level,
4714    finish up that level of constructor.  If a single expression
4715    with redundant braces initialized that level, return the
4716    c_expr structure for that expression.  Otherwise, the original_code
4717    element is set to ERROR_MARK.
4718    If we were outputting the elements as they are read, return 0 as the value
4719    from inner levels (process_init_element ignores that),
4720    but return error_mark_node as the value from the outermost level
4721    (that's what we want to put in DECL_INITIAL).
4722    Otherwise, return a CONSTRUCTOR expression as the value.  */
4723
4724 struct c_expr
4725 pop_init_level (int implicit)
4726 {
4727   struct constructor_stack *p;
4728   struct c_expr ret;
4729   ret.value = 0;
4730   ret.original_code = ERROR_MARK;
4731
4732   if (implicit == 0)
4733     {
4734       /* When we come to an explicit close brace,
4735          pop any inner levels that didn't have explicit braces.  */
4736       while (constructor_stack->implicit)
4737         process_init_element (pop_init_level (1));
4738
4739       if (constructor_range_stack)
4740         abort ();
4741     }
4742
4743   /* Now output all pending elements.  */
4744   constructor_incremental = 1;
4745   output_pending_init_elements (1);
4746
4747   p = constructor_stack;
4748
4749   /* Error for initializing a flexible array member, or a zero-length
4750      array member in an inappropriate context.  */
4751   if (constructor_type && constructor_fields
4752       && TREE_CODE (constructor_type) == ARRAY_TYPE
4753       && TYPE_DOMAIN (constructor_type)
4754       && ! TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
4755     {
4756       /* Silently discard empty initializations.  The parser will
4757          already have pedwarned for empty brackets.  */
4758       if (integer_zerop (constructor_unfilled_index))
4759         constructor_type = NULL_TREE;
4760       else if (! TYPE_SIZE (constructor_type))
4761         {
4762           if (constructor_depth > 2)
4763             error_init ("initialization of flexible array member in a nested context");
4764           else if (pedantic)
4765             pedwarn_init ("initialization of a flexible array member");
4766
4767           /* We have already issued an error message for the existence
4768              of a flexible array member not at the end of the structure.
4769              Discard the initializer so that we do not abort later.  */
4770           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
4771             constructor_type = NULL_TREE;
4772         }
4773       else
4774         /* Zero-length arrays are no longer special, so we should no longer
4775            get here.  */
4776         abort ();
4777     }
4778
4779   /* Warn when some struct elements are implicitly initialized to zero.  */
4780   if (warn_missing_field_initializers
4781       && constructor_type
4782       && TREE_CODE (constructor_type) == RECORD_TYPE
4783       && constructor_unfilled_fields)
4784     {
4785         /* Do not warn for flexible array members or zero-length arrays.  */
4786         while (constructor_unfilled_fields
4787                && (! DECL_SIZE (constructor_unfilled_fields)
4788                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
4789           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
4790
4791         /* Do not warn if this level of the initializer uses member
4792            designators; it is likely to be deliberate.  */
4793         if (constructor_unfilled_fields && !constructor_designated)
4794           {
4795             push_member_name (constructor_unfilled_fields);
4796             warning_init ("missing initializer");
4797             RESTORE_SPELLING_DEPTH (constructor_depth);
4798           }
4799     }
4800
4801   /* Pad out the end of the structure.  */
4802   if (p->replacement_value.value)
4803     /* If this closes a superfluous brace pair,
4804        just pass out the element between them.  */
4805     ret = p->replacement_value;
4806   else if (constructor_type == 0)
4807     ;
4808   else if (TREE_CODE (constructor_type) != RECORD_TYPE
4809            && TREE_CODE (constructor_type) != UNION_TYPE
4810            && TREE_CODE (constructor_type) != ARRAY_TYPE
4811            && TREE_CODE (constructor_type) != VECTOR_TYPE)
4812     {
4813       /* A nonincremental scalar initializer--just return
4814          the element, after verifying there is just one.  */
4815       if (constructor_elements == 0)
4816         {
4817           if (!constructor_erroneous)
4818             error_init ("empty scalar initializer");
4819           ret.value = error_mark_node;
4820         }
4821       else if (TREE_CHAIN (constructor_elements) != 0)
4822         {
4823           error_init ("extra elements in scalar initializer");
4824           ret.value = TREE_VALUE (constructor_elements);
4825         }
4826       else
4827         ret.value = TREE_VALUE (constructor_elements);
4828     }
4829   else
4830     {
4831       if (constructor_erroneous)
4832         ret.value = error_mark_node;
4833       else
4834         {
4835           ret.value = build_constructor (constructor_type,
4836                                          nreverse (constructor_elements));
4837           if (constructor_constant)
4838             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
4839           if (constructor_constant && constructor_simple)
4840             TREE_STATIC (ret.value) = 1;
4841         }
4842     }
4843
4844   constructor_type = p->type;
4845   constructor_fields = p->fields;
4846   constructor_index = p->index;
4847   constructor_max_index = p->max_index;
4848   constructor_unfilled_index = p->unfilled_index;
4849   constructor_unfilled_fields = p->unfilled_fields;
4850   constructor_bit_index = p->bit_index;
4851   constructor_elements = p->elements;
4852   constructor_constant = p->constant;
4853   constructor_simple = p->simple;
4854   constructor_erroneous = p->erroneous;
4855   constructor_incremental = p->incremental;
4856   constructor_designated = p->designated;
4857   constructor_pending_elts = p->pending_elts;
4858   constructor_depth = p->depth;
4859   if (!p->implicit)
4860     constructor_range_stack = p->range_stack;
4861   RESTORE_SPELLING_DEPTH (constructor_depth);
4862
4863   constructor_stack = p->next;
4864   free (p);
4865
4866   if (ret.value == 0)
4867     {
4868       if (constructor_stack == 0)
4869         {
4870           ret.value = error_mark_node;
4871           return ret;
4872         }
4873       return ret;
4874     }
4875   return ret;
4876 }
4877
4878 /* Common handling for both array range and field name designators.
4879    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
4880
4881 static int
4882 set_designator (int array)
4883 {
4884   tree subtype;
4885   enum tree_code subcode;
4886
4887   /* Don't die if an entire brace-pair level is superfluous
4888      in the containing level.  */
4889   if (constructor_type == 0)
4890     return 1;
4891
4892   /* If there were errors in this designator list already, bail out silently.  */
4893   if (designator_errorneous)
4894     return 1;
4895
4896   if (!designator_depth)
4897     {
4898       if (constructor_range_stack)
4899         abort ();
4900
4901       /* Designator list starts at the level of closest explicit
4902          braces.  */
4903       while (constructor_stack->implicit)
4904         process_init_element (pop_init_level (1));
4905       constructor_designated = 1;
4906       return 0;
4907     }
4908
4909   if (constructor_no_implicit)
4910     {
4911       error_init ("initialization designators may not nest");
4912       return 1;
4913     }
4914
4915   if (TREE_CODE (constructor_type) == RECORD_TYPE
4916       || TREE_CODE (constructor_type) == UNION_TYPE)
4917     {
4918       subtype = TREE_TYPE (constructor_fields);
4919       if (subtype != error_mark_node)
4920         subtype = TYPE_MAIN_VARIANT (subtype);
4921     }
4922   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4923     {
4924       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
4925     }
4926   else
4927     abort ();
4928
4929   subcode = TREE_CODE (subtype);
4930   if (array && subcode != ARRAY_TYPE)
4931     {
4932       error_init ("array index in non-array initializer");
4933       return 1;
4934     }
4935   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
4936     {
4937       error_init ("field name not in record or union initializer");
4938       return 1;
4939     }
4940
4941   constructor_designated = 1;
4942   push_init_level (2);
4943   return 0;
4944 }
4945
4946 /* If there are range designators in designator list, push a new designator
4947    to constructor_range_stack.  RANGE_END is end of such stack range or
4948    NULL_TREE if there is no range designator at this level.  */
4949
4950 static void
4951 push_range_stack (tree range_end)
4952 {
4953   struct constructor_range_stack *p;
4954
4955   p = GGC_NEW (struct constructor_range_stack);
4956   p->prev = constructor_range_stack;
4957   p->next = 0;
4958   p->fields = constructor_fields;
4959   p->range_start = constructor_index;
4960   p->index = constructor_index;
4961   p->stack = constructor_stack;
4962   p->range_end = range_end;
4963   if (constructor_range_stack)
4964     constructor_range_stack->next = p;
4965   constructor_range_stack = p;
4966 }
4967
4968 /* Within an array initializer, specify the next index to be initialized.
4969    FIRST is that index.  If LAST is nonzero, then initialize a range
4970    of indices, running from FIRST through LAST.  */
4971
4972 void
4973 set_init_index (tree first, tree last)
4974 {
4975   if (set_designator (1))
4976     return;
4977
4978   designator_errorneous = 1;
4979
4980   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
4981       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
4982     {
4983       error_init ("array index in initializer not of integer type");
4984       return;
4985     }
4986
4987   while ((TREE_CODE (first) == NOP_EXPR
4988           || TREE_CODE (first) == CONVERT_EXPR
4989           || TREE_CODE (first) == NON_LVALUE_EXPR)
4990          && (TYPE_MODE (TREE_TYPE (first))
4991              == TYPE_MODE (TREE_TYPE (TREE_OPERAND (first, 0)))))
4992     first = TREE_OPERAND (first, 0);
4993
4994   if (last)
4995     while ((TREE_CODE (last) == NOP_EXPR
4996             || TREE_CODE (last) == CONVERT_EXPR
4997             || TREE_CODE (last) == NON_LVALUE_EXPR)
4998            && (TYPE_MODE (TREE_TYPE (last))
4999                == TYPE_MODE (TREE_TYPE (TREE_OPERAND (last, 0)))))
5000       last = TREE_OPERAND (last, 0);
5001
5002   if (TREE_CODE (first) != INTEGER_CST)
5003     error_init ("nonconstant array index in initializer");
5004   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5005     error_init ("nonconstant array index in initializer");
5006   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5007     error_init ("array index in non-array initializer");
5008   else if (tree_int_cst_sgn (first) == -1)
5009     error_init ("array index in initializer exceeds array bounds");
5010   else if (constructor_max_index
5011            && tree_int_cst_lt (constructor_max_index, first))
5012     error_init ("array index in initializer exceeds array bounds");
5013   else
5014     {
5015       constructor_index = convert (bitsizetype, first);
5016
5017       if (last)
5018         {
5019           if (tree_int_cst_equal (first, last))
5020             last = 0;
5021           else if (tree_int_cst_lt (last, first))
5022             {
5023               error_init ("empty index range in initializer");
5024               last = 0;
5025             }
5026           else
5027             {
5028               last = convert (bitsizetype, last);
5029               if (constructor_max_index != 0
5030                   && tree_int_cst_lt (constructor_max_index, last))
5031                 {
5032                   error_init ("array index range in initializer exceeds array bounds");
5033                   last = 0;
5034                 }
5035             }
5036         }
5037
5038       designator_depth++;
5039       designator_errorneous = 0;
5040       if (constructor_range_stack || last)
5041         push_range_stack (last);
5042     }
5043 }
5044
5045 /* Within a struct initializer, specify the next field to be initialized.  */
5046
5047 void
5048 set_init_label (tree fieldname)
5049 {
5050   tree tail;
5051
5052   if (set_designator (0))
5053     return;
5054
5055   designator_errorneous = 1;
5056
5057   if (TREE_CODE (constructor_type) != RECORD_TYPE
5058       && TREE_CODE (constructor_type) != UNION_TYPE)
5059     {
5060       error_init ("field name not in record or union initializer");
5061       return;
5062     }
5063
5064   for (tail = TYPE_FIELDS (constructor_type); tail;
5065        tail = TREE_CHAIN (tail))
5066     {
5067       if (DECL_NAME (tail) == fieldname)
5068         break;
5069     }
5070
5071   if (tail == 0)
5072     error ("unknown field `%s' specified in initializer",
5073            IDENTIFIER_POINTER (fieldname));
5074   else
5075     {
5076       constructor_fields = tail;
5077       designator_depth++;
5078       designator_errorneous = 0;
5079       if (constructor_range_stack)
5080         push_range_stack (NULL_TREE);
5081     }
5082 }
5083 \f
5084 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5085    identifies the initializer, either array index or field in a structure.
5086    VALUE is the value of that index or field.  */
5087
5088 static void
5089 add_pending_init (tree purpose, tree value)
5090 {
5091   struct init_node *p, **q, *r;
5092
5093   q = &constructor_pending_elts;
5094   p = 0;
5095
5096   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5097     {
5098       while (*q != 0)
5099         {
5100           p = *q;
5101           if (tree_int_cst_lt (purpose, p->purpose))
5102             q = &p->left;
5103           else if (tree_int_cst_lt (p->purpose, purpose))
5104             q = &p->right;
5105           else
5106             {
5107               if (TREE_SIDE_EFFECTS (p->value))
5108                 warning_init ("initialized field with side-effects overwritten");
5109               p->value = value;
5110               return;
5111             }
5112         }
5113     }
5114   else
5115     {
5116       tree bitpos;
5117
5118       bitpos = bit_position (purpose);
5119       while (*q != NULL)
5120         {
5121           p = *q;
5122           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5123             q = &p->left;
5124           else if (p->purpose != purpose)
5125             q = &p->right;
5126           else
5127             {
5128               if (TREE_SIDE_EFFECTS (p->value))
5129                 warning_init ("initialized field with side-effects overwritten");
5130               p->value = value;
5131               return;
5132             }
5133         }
5134     }
5135
5136   r = GGC_NEW (struct init_node);
5137   r->purpose = purpose;
5138   r->value = value;
5139
5140   *q = r;
5141   r->parent = p;
5142   r->left = 0;
5143   r->right = 0;
5144   r->balance = 0;
5145
5146   while (p)
5147     {
5148       struct init_node *s;
5149
5150       if (r == p->left)
5151         {
5152           if (p->balance == 0)
5153             p->balance = -1;
5154           else if (p->balance < 0)
5155             {
5156               if (r->balance < 0)
5157                 {
5158                   /* L rotation.  */
5159                   p->left = r->right;
5160                   if (p->left)
5161                     p->left->parent = p;
5162                   r->right = p;
5163
5164                   p->balance = 0;
5165                   r->balance = 0;
5166
5167                   s = p->parent;
5168                   p->parent = r;
5169                   r->parent = s;
5170                   if (s)
5171                     {
5172                       if (s->left == p)
5173                         s->left = r;
5174                       else
5175                         s->right = r;
5176                     }
5177                   else
5178                     constructor_pending_elts = r;
5179                 }
5180               else
5181                 {
5182                   /* LR rotation.  */
5183                   struct init_node *t = r->right;
5184
5185                   r->right = t->left;
5186                   if (r->right)
5187                     r->right->parent = r;
5188                   t->left = r;
5189
5190                   p->left = t->right;
5191                   if (p->left)
5192                     p->left->parent = p;
5193                   t->right = p;
5194
5195                   p->balance = t->balance < 0;
5196                   r->balance = -(t->balance > 0);
5197                   t->balance = 0;
5198
5199                   s = p->parent;
5200                   p->parent = t;
5201                   r->parent = t;
5202                   t->parent = s;
5203                   if (s)
5204                     {
5205                       if (s->left == p)
5206                         s->left = t;
5207                       else
5208                         s->right = t;
5209                     }
5210                   else
5211                     constructor_pending_elts = t;
5212                 }
5213               break;
5214             }
5215           else
5216             {
5217               /* p->balance == +1; growth of left side balances the node.  */
5218               p->balance = 0;
5219               break;
5220             }
5221         }
5222       else /* r == p->right */
5223         {
5224           if (p->balance == 0)
5225             /* Growth propagation from right side.  */
5226             p->balance++;
5227           else if (p->balance > 0)
5228             {
5229               if (r->balance > 0)
5230                 {
5231                   /* R rotation.  */
5232                   p->right = r->left;
5233                   if (p->right)
5234                     p->right->parent = p;
5235                   r->left = p;
5236
5237                   p->balance = 0;
5238                   r->balance = 0;
5239
5240                   s = p->parent;
5241                   p->parent = r;
5242                   r->parent = s;
5243                   if (s)
5244                     {
5245                       if (s->left == p)
5246                         s->left = r;
5247                       else
5248                         s->right = r;
5249                     }
5250                   else
5251                     constructor_pending_elts = r;
5252                 }
5253               else /* r->balance == -1 */
5254                 {
5255                   /* RL rotation */
5256                   struct init_node *t = r->left;
5257
5258                   r->left = t->right;
5259                   if (r->left)
5260                     r->left->parent = r;
5261                   t->right = r;
5262
5263                   p->right = t->left;
5264                   if (p->right)
5265                     p->right->parent = p;
5266                   t->left = p;
5267
5268                   r->balance = (t->balance < 0);
5269                   p->balance = -(t->balance > 0);
5270                   t->balance = 0;
5271
5272                   s = p->parent;
5273                   p->parent = t;
5274                   r->parent = t;
5275                   t->parent = s;
5276                   if (s)
5277                     {
5278                       if (s->left == p)
5279                         s->left = t;
5280                       else
5281                         s->right = t;
5282                     }
5283                   else
5284                     constructor_pending_elts = t;
5285                 }
5286               break;
5287             }
5288           else
5289             {
5290               /* p->balance == -1; growth of right side balances the node.  */
5291               p->balance = 0;
5292               break;
5293             }
5294         }
5295
5296       r = p;
5297       p = p->parent;
5298     }
5299 }
5300
5301 /* Build AVL tree from a sorted chain.  */
5302
5303 static void
5304 set_nonincremental_init (void)
5305 {
5306   tree chain;
5307
5308   if (TREE_CODE (constructor_type) != RECORD_TYPE
5309       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5310     return;
5311
5312   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5313     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5314   constructor_elements = 0;
5315   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5316     {
5317       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5318       /* Skip any nameless bit fields at the beginning.  */
5319       while (constructor_unfilled_fields != 0
5320              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5321              && DECL_NAME (constructor_unfilled_fields) == 0)
5322         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5323
5324     }
5325   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5326     {
5327       if (TYPE_DOMAIN (constructor_type))
5328         constructor_unfilled_index
5329             = convert (bitsizetype,
5330                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5331       else
5332         constructor_unfilled_index = bitsize_zero_node;
5333     }
5334   constructor_incremental = 0;
5335 }
5336
5337 /* Build AVL tree from a string constant.  */
5338
5339 static void
5340 set_nonincremental_init_from_string (tree str)
5341 {
5342   tree value, purpose, type;
5343   HOST_WIDE_INT val[2];
5344   const char *p, *end;
5345   int byte, wchar_bytes, charwidth, bitpos;
5346
5347   if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5348     abort ();
5349
5350   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5351       == TYPE_PRECISION (char_type_node))
5352     wchar_bytes = 1;
5353   else if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5354            == TYPE_PRECISION (wchar_type_node))
5355     wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5356   else
5357     abort ();
5358
5359   charwidth = TYPE_PRECISION (char_type_node);
5360   type = TREE_TYPE (constructor_type);
5361   p = TREE_STRING_POINTER (str);
5362   end = p + TREE_STRING_LENGTH (str);
5363
5364   for (purpose = bitsize_zero_node;
5365        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5366        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5367     {
5368       if (wchar_bytes == 1)
5369         {
5370           val[1] = (unsigned char) *p++;
5371           val[0] = 0;
5372         }
5373       else
5374         {
5375           val[0] = 0;
5376           val[1] = 0;
5377           for (byte = 0; byte < wchar_bytes; byte++)
5378             {
5379               if (BYTES_BIG_ENDIAN)
5380                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5381               else
5382                 bitpos = byte * charwidth;
5383               val[bitpos < HOST_BITS_PER_WIDE_INT]
5384                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5385                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5386             }
5387         }
5388
5389       if (!TYPE_UNSIGNED (type))
5390         {
5391           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5392           if (bitpos < HOST_BITS_PER_WIDE_INT)
5393             {
5394               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5395                 {
5396                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5397                   val[0] = -1;
5398                 }
5399             }
5400           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5401             {
5402               if (val[1] < 0)
5403                 val[0] = -1;
5404             }
5405           else if (val[0] & (((HOST_WIDE_INT) 1)
5406                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5407             val[0] |= ((HOST_WIDE_INT) -1)
5408                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5409         }
5410
5411       value = build_int_cst (type, val[1], val[0]);
5412       add_pending_init (purpose, value);
5413     }
5414
5415   constructor_incremental = 0;
5416 }
5417
5418 /* Return value of FIELD in pending initializer or zero if the field was
5419    not initialized yet.  */
5420
5421 static tree
5422 find_init_member (tree field)
5423 {
5424   struct init_node *p;
5425
5426   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5427     {
5428       if (constructor_incremental
5429           && tree_int_cst_lt (field, constructor_unfilled_index))
5430         set_nonincremental_init ();
5431
5432       p = constructor_pending_elts;
5433       while (p)
5434         {
5435           if (tree_int_cst_lt (field, p->purpose))
5436             p = p->left;
5437           else if (tree_int_cst_lt (p->purpose, field))
5438             p = p->right;
5439           else
5440             return p->value;
5441         }
5442     }
5443   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5444     {
5445       tree bitpos = bit_position (field);
5446
5447       if (constructor_incremental
5448           && (!constructor_unfilled_fields
5449               || tree_int_cst_lt (bitpos,
5450                                   bit_position (constructor_unfilled_fields))))
5451         set_nonincremental_init ();
5452
5453       p = constructor_pending_elts;
5454       while (p)
5455         {
5456           if (field == p->purpose)
5457             return p->value;
5458           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5459             p = p->left;
5460           else
5461             p = p->right;
5462         }
5463     }
5464   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5465     {
5466       if (constructor_elements
5467           && TREE_PURPOSE (constructor_elements) == field)
5468         return TREE_VALUE (constructor_elements);
5469     }
5470   return 0;
5471 }
5472
5473 /* "Output" the next constructor element.
5474    At top level, really output it to assembler code now.
5475    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5476    TYPE is the data type that the containing data type wants here.
5477    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5478    If VALUE is a string constant, STRICT_STRING is true if it is
5479    unparenthesized or we should not warn here for it being parenthesized.
5480    For other types of VALUE, STRICT_STRING is not used.
5481
5482    PENDING if non-nil means output pending elements that belong
5483    right after this element.  (PENDING is normally 1;
5484    it is 0 while outputting pending elements, to avoid recursion.)  */
5485
5486 static void
5487 output_init_element (tree value, bool strict_string, tree type, tree field,
5488                      int pending)
5489 {
5490   if (type == error_mark_node)
5491     {
5492       constructor_erroneous = 1;
5493       return;
5494     }
5495   if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
5496       || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5497           && !(TREE_CODE (value) == STRING_CST
5498                && TREE_CODE (type) == ARRAY_TYPE
5499                && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5500           && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5501                          TYPE_MAIN_VARIANT (type))))
5502     value = default_conversion (value);
5503
5504   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5505       && require_constant_value && !flag_isoc99 && pending)
5506     {
5507       /* As an extension, allow initializing objects with static storage
5508          duration with compound literals (which are then treated just as
5509          the brace enclosed list they contain).  */
5510       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5511       value = DECL_INITIAL (decl);
5512     }
5513
5514   if (value == error_mark_node)
5515     constructor_erroneous = 1;
5516   else if (!TREE_CONSTANT (value))
5517     constructor_constant = 0;
5518   else if (initializer_constant_valid_p (value, TREE_TYPE (value)) == 0
5519            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5520                 || TREE_CODE (constructor_type) == UNION_TYPE)
5521                && DECL_C_BIT_FIELD (field)
5522                && TREE_CODE (value) != INTEGER_CST))
5523     constructor_simple = 0;
5524
5525   if (require_constant_value && ! TREE_CONSTANT (value))
5526     {
5527       error_init ("initializer element is not constant");
5528       value = error_mark_node;
5529     }
5530   else if (require_constant_elements
5531            && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
5532     pedwarn ("initializer element is not computable at load time");
5533
5534   /* If this field is empty (and not at the end of structure),
5535      don't do anything other than checking the initializer.  */
5536   if (field
5537       && (TREE_TYPE (field) == error_mark_node
5538           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5539               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5540               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5541                   || TREE_CHAIN (field)))))
5542     return;
5543
5544   value = digest_init (type, value, strict_string, require_constant_value);
5545   if (value == error_mark_node)
5546     {
5547       constructor_erroneous = 1;
5548       return;
5549     }
5550
5551   /* If this element doesn't come next in sequence,
5552      put it on constructor_pending_elts.  */
5553   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5554       && (!constructor_incremental
5555           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5556     {
5557       if (constructor_incremental
5558           && tree_int_cst_lt (field, constructor_unfilled_index))
5559         set_nonincremental_init ();
5560
5561       add_pending_init (field, value);
5562       return;
5563     }
5564   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5565            && (!constructor_incremental
5566                || field != constructor_unfilled_fields))
5567     {
5568       /* We do this for records but not for unions.  In a union,
5569          no matter which field is specified, it can be initialized
5570          right away since it starts at the beginning of the union.  */
5571       if (constructor_incremental)
5572         {
5573           if (!constructor_unfilled_fields)
5574             set_nonincremental_init ();
5575           else
5576             {
5577               tree bitpos, unfillpos;
5578
5579               bitpos = bit_position (field);
5580               unfillpos = bit_position (constructor_unfilled_fields);
5581
5582               if (tree_int_cst_lt (bitpos, unfillpos))
5583                 set_nonincremental_init ();
5584             }
5585         }
5586
5587       add_pending_init (field, value);
5588       return;
5589     }
5590   else if (TREE_CODE (constructor_type) == UNION_TYPE
5591            && constructor_elements)
5592     {
5593       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5594         warning_init ("initialized field with side-effects overwritten");
5595
5596       /* We can have just one union field set.  */
5597       constructor_elements = 0;
5598     }
5599
5600   /* Otherwise, output this element either to
5601      constructor_elements or to the assembler file.  */
5602
5603   if (field && TREE_CODE (field) == INTEGER_CST)
5604     field = copy_node (field);
5605   constructor_elements
5606     = tree_cons (field, value, constructor_elements);
5607
5608   /* Advance the variable that indicates sequential elements output.  */
5609   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5610     constructor_unfilled_index
5611       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5612                     bitsize_one_node);
5613   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5614     {
5615       constructor_unfilled_fields
5616         = TREE_CHAIN (constructor_unfilled_fields);
5617
5618       /* Skip any nameless bit fields.  */
5619       while (constructor_unfilled_fields != 0
5620              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5621              && DECL_NAME (constructor_unfilled_fields) == 0)
5622         constructor_unfilled_fields =
5623           TREE_CHAIN (constructor_unfilled_fields);
5624     }
5625   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5626     constructor_unfilled_fields = 0;
5627
5628   /* Now output any pending elements which have become next.  */
5629   if (pending)
5630     output_pending_init_elements (0);
5631 }
5632
5633 /* Output any pending elements which have become next.
5634    As we output elements, constructor_unfilled_{fields,index}
5635    advances, which may cause other elements to become next;
5636    if so, they too are output.
5637
5638    If ALL is 0, we return when there are
5639    no more pending elements to output now.
5640
5641    If ALL is 1, we output space as necessary so that
5642    we can output all the pending elements.  */
5643
5644 static void
5645 output_pending_init_elements (int all)
5646 {
5647   struct init_node *elt = constructor_pending_elts;
5648   tree next;
5649
5650  retry:
5651
5652   /* Look through the whole pending tree.
5653      If we find an element that should be output now,
5654      output it.  Otherwise, set NEXT to the element
5655      that comes first among those still pending.  */
5656
5657   next = 0;
5658   while (elt)
5659     {
5660       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5661         {
5662           if (tree_int_cst_equal (elt->purpose,
5663                                   constructor_unfilled_index))
5664             output_init_element (elt->value, true,
5665                                  TREE_TYPE (constructor_type),
5666                                  constructor_unfilled_index, 0);
5667           else if (tree_int_cst_lt (constructor_unfilled_index,
5668                                     elt->purpose))
5669             {
5670               /* Advance to the next smaller node.  */
5671               if (elt->left)
5672                 elt = elt->left;
5673               else
5674                 {
5675                   /* We have reached the smallest node bigger than the
5676                      current unfilled index.  Fill the space first.  */
5677                   next = elt->purpose;
5678                   break;
5679                 }
5680             }
5681           else
5682             {
5683               /* Advance to the next bigger node.  */
5684               if (elt->right)
5685                 elt = elt->right;
5686               else
5687                 {
5688                   /* We have reached the biggest node in a subtree.  Find
5689                      the parent of it, which is the next bigger node.  */
5690                   while (elt->parent && elt->parent->right == elt)
5691                     elt = elt->parent;
5692                   elt = elt->parent;
5693                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5694                                               elt->purpose))
5695                     {
5696                       next = elt->purpose;
5697                       break;
5698                     }
5699                 }
5700             }
5701         }
5702       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5703                || TREE_CODE (constructor_type) == UNION_TYPE)
5704         {
5705           tree ctor_unfilled_bitpos, elt_bitpos;
5706
5707           /* If the current record is complete we are done.  */
5708           if (constructor_unfilled_fields == 0)
5709             break;
5710
5711           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5712           elt_bitpos = bit_position (elt->purpose);
5713           /* We can't compare fields here because there might be empty
5714              fields in between.  */
5715           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
5716             {
5717               constructor_unfilled_fields = elt->purpose;
5718               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
5719                                    elt->purpose, 0);
5720             }
5721           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
5722             {
5723               /* Advance to the next smaller node.  */
5724               if (elt->left)
5725                 elt = elt->left;
5726               else
5727                 {
5728                   /* We have reached the smallest node bigger than the
5729                      current unfilled field.  Fill the space first.  */
5730                   next = elt->purpose;
5731                   break;
5732                 }
5733             }
5734           else
5735             {
5736               /* Advance to the next bigger node.  */
5737               if (elt->right)
5738                 elt = elt->right;
5739               else
5740                 {
5741                   /* We have reached the biggest node in a subtree.  Find
5742                      the parent of it, which is the next bigger node.  */
5743                   while (elt->parent && elt->parent->right == elt)
5744                     elt = elt->parent;
5745                   elt = elt->parent;
5746                   if (elt
5747                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
5748                                            bit_position (elt->purpose))))
5749                     {
5750                       next = elt->purpose;
5751                       break;
5752                     }
5753                 }
5754             }
5755         }
5756     }
5757
5758   /* Ordinarily return, but not if we want to output all
5759      and there are elements left.  */
5760   if (! (all && next != 0))
5761     return;
5762
5763   /* If it's not incremental, just skip over the gap, so that after
5764      jumping to retry we will output the next successive element.  */
5765   if (TREE_CODE (constructor_type) == RECORD_TYPE
5766       || TREE_CODE (constructor_type) == UNION_TYPE)
5767     constructor_unfilled_fields = next;
5768   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5769     constructor_unfilled_index = next;
5770
5771   /* ELT now points to the node in the pending tree with the next
5772      initializer to output.  */
5773   goto retry;
5774 }
5775 \f
5776 /* Add one non-braced element to the current constructor level.
5777    This adjusts the current position within the constructor's type.
5778    This may also start or terminate implicit levels
5779    to handle a partly-braced initializer.
5780
5781    Once this has found the correct level for the new element,
5782    it calls output_init_element.  */
5783
5784 void
5785 process_init_element (struct c_expr value)
5786 {
5787   tree orig_value = value.value;
5788   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
5789   bool strict_string = value.original_code == STRING_CST;
5790
5791   designator_depth = 0;
5792   designator_errorneous = 0;
5793
5794   /* Handle superfluous braces around string cst as in
5795      char x[] = {"foo"}; */
5796   if (string_flag
5797       && constructor_type
5798       && TREE_CODE (constructor_type) == ARRAY_TYPE
5799       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
5800       && integer_zerop (constructor_unfilled_index))
5801     {
5802       if (constructor_stack->replacement_value.value)
5803         error_init ("excess elements in char array initializer");
5804       constructor_stack->replacement_value = value;
5805       return;
5806     }
5807
5808   if (constructor_stack->replacement_value.value != 0)
5809     {
5810       error_init ("excess elements in struct initializer");
5811       return;
5812     }
5813
5814   /* Ignore elements of a brace group if it is entirely superfluous
5815      and has already been diagnosed.  */
5816   if (constructor_type == 0)
5817     return;
5818
5819   /* If we've exhausted any levels that didn't have braces,
5820      pop them now.  */
5821   while (constructor_stack->implicit)
5822     {
5823       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5824            || TREE_CODE (constructor_type) == UNION_TYPE)
5825           && constructor_fields == 0)
5826         process_init_element (pop_init_level (1));
5827       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5828                && (constructor_max_index == 0
5829                    || tree_int_cst_lt (constructor_max_index,
5830                                        constructor_index)))
5831         process_init_element (pop_init_level (1));
5832       else
5833         break;
5834     }
5835
5836   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
5837   if (constructor_range_stack)
5838     {
5839       /* If value is a compound literal and we'll be just using its
5840          content, don't put it into a SAVE_EXPR.  */
5841       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
5842           || !require_constant_value
5843           || flag_isoc99)
5844         value.value = save_expr (value.value);
5845     }
5846
5847   while (1)
5848     {
5849       if (TREE_CODE (constructor_type) == RECORD_TYPE)
5850         {
5851           tree fieldtype;
5852           enum tree_code fieldcode;
5853
5854           if (constructor_fields == 0)
5855             {
5856               pedwarn_init ("excess elements in struct initializer");
5857               break;
5858             }
5859
5860           fieldtype = TREE_TYPE (constructor_fields);
5861           if (fieldtype != error_mark_node)
5862             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5863           fieldcode = TREE_CODE (fieldtype);
5864
5865           /* Error for non-static initialization of a flexible array member.  */
5866           if (fieldcode == ARRAY_TYPE
5867               && !require_constant_value
5868               && TYPE_SIZE (fieldtype) == NULL_TREE
5869               && TREE_CHAIN (constructor_fields) == NULL_TREE)
5870             {
5871               error_init ("non-static initialization of a flexible array member");
5872               break;
5873             }
5874
5875           /* Accept a string constant to initialize a subarray.  */
5876           if (value.value != 0
5877               && fieldcode == ARRAY_TYPE
5878               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
5879               && string_flag)
5880             value.value = orig_value;
5881           /* Otherwise, if we have come to a subaggregate,
5882              and we don't have an element of its type, push into it.  */
5883           else if (value.value != 0 && !constructor_no_implicit
5884                    && value.value != error_mark_node
5885                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5886                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5887                        || fieldcode == UNION_TYPE))
5888             {
5889               push_init_level (1);
5890               continue;
5891             }
5892
5893           if (value.value)
5894             {
5895               push_member_name (constructor_fields);
5896               output_init_element (value.value, strict_string,
5897                                    fieldtype, constructor_fields, 1);
5898               RESTORE_SPELLING_DEPTH (constructor_depth);
5899             }
5900           else
5901             /* Do the bookkeeping for an element that was
5902                directly output as a constructor.  */
5903             {
5904               /* For a record, keep track of end position of last field.  */
5905               if (DECL_SIZE (constructor_fields))
5906                 constructor_bit_index
5907                   = size_binop (PLUS_EXPR,
5908                                 bit_position (constructor_fields),
5909                                 DECL_SIZE (constructor_fields));
5910
5911               /* If the current field was the first one not yet written out,
5912                  it isn't now, so update.  */
5913               if (constructor_unfilled_fields == constructor_fields)
5914                 {
5915                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5916                   /* Skip any nameless bit fields.  */
5917                   while (constructor_unfilled_fields != 0
5918                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5919                          && DECL_NAME (constructor_unfilled_fields) == 0)
5920                     constructor_unfilled_fields =
5921                       TREE_CHAIN (constructor_unfilled_fields);
5922                 }
5923             }
5924
5925           constructor_fields = TREE_CHAIN (constructor_fields);
5926           /* Skip any nameless bit fields at the beginning.  */
5927           while (constructor_fields != 0
5928                  && DECL_C_BIT_FIELD (constructor_fields)
5929                  && DECL_NAME (constructor_fields) == 0)
5930             constructor_fields = TREE_CHAIN (constructor_fields);
5931         }
5932       else if (TREE_CODE (constructor_type) == UNION_TYPE)
5933         {
5934           tree fieldtype;
5935           enum tree_code fieldcode;
5936
5937           if (constructor_fields == 0)
5938             {
5939               pedwarn_init ("excess elements in union initializer");
5940               break;
5941             }
5942
5943           fieldtype = TREE_TYPE (constructor_fields);
5944           if (fieldtype != error_mark_node)
5945             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5946           fieldcode = TREE_CODE (fieldtype);
5947
5948           /* Warn that traditional C rejects initialization of unions.
5949              We skip the warning if the value is zero.  This is done
5950              under the assumption that the zero initializer in user
5951              code appears conditioned on e.g. __STDC__ to avoid
5952              "missing initializer" warnings and relies on default
5953              initialization to zero in the traditional C case.
5954              We also skip the warning if the initializer is designated,
5955              again on the assumption that this must be conditional on
5956              __STDC__ anyway (and we've already complained about the
5957              member-designator already).  */
5958           if (warn_traditional && !in_system_header && !constructor_designated
5959               && !(value.value && (integer_zerop (value.value)
5960                                    || real_zerop (value.value))))
5961             warning ("traditional C rejects initialization of unions");
5962
5963           /* Accept a string constant to initialize a subarray.  */
5964           if (value.value != 0
5965               && fieldcode == ARRAY_TYPE
5966               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
5967               && string_flag)
5968             value.value = orig_value;
5969           /* Otherwise, if we have come to a subaggregate,
5970              and we don't have an element of its type, push into it.  */
5971           else if (value.value != 0 && !constructor_no_implicit
5972                    && value.value != error_mark_node
5973                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
5974                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5975                        || fieldcode == UNION_TYPE))
5976             {
5977               push_init_level (1);
5978               continue;
5979             }
5980
5981           if (value.value)
5982             {
5983               push_member_name (constructor_fields);
5984               output_init_element (value.value, strict_string,
5985                                    fieldtype, constructor_fields, 1);
5986               RESTORE_SPELLING_DEPTH (constructor_depth);
5987             }
5988           else
5989             /* Do the bookkeeping for an element that was
5990                directly output as a constructor.  */
5991             {
5992               constructor_bit_index = DECL_SIZE (constructor_fields);
5993               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5994             }
5995
5996           constructor_fields = 0;
5997         }
5998       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5999         {
6000           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6001           enum tree_code eltcode = TREE_CODE (elttype);
6002
6003           /* Accept a string constant to initialize a subarray.  */
6004           if (value.value != 0
6005               && eltcode == ARRAY_TYPE
6006               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6007               && string_flag)
6008             value.value = orig_value;
6009           /* Otherwise, if we have come to a subaggregate,
6010              and we don't have an element of its type, push into it.  */
6011           else if (value.value != 0 && !constructor_no_implicit
6012                    && value.value != error_mark_node
6013                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6014                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6015                        || eltcode == UNION_TYPE))
6016             {
6017               push_init_level (1);
6018               continue;
6019             }
6020
6021           if (constructor_max_index != 0
6022               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6023                   || integer_all_onesp (constructor_max_index)))
6024             {
6025               pedwarn_init ("excess elements in array initializer");
6026               break;
6027             }
6028
6029           /* Now output the actual element.  */
6030           if (value.value)
6031             {
6032               push_array_bounds (tree_low_cst (constructor_index, 0));
6033               output_init_element (value.value, strict_string,
6034                                    elttype, constructor_index, 1);
6035               RESTORE_SPELLING_DEPTH (constructor_depth);
6036             }
6037
6038           constructor_index
6039             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6040
6041           if (!value.value)
6042             /* If we are doing the bookkeeping for an element that was
6043                directly output as a constructor, we must update
6044                constructor_unfilled_index.  */
6045             constructor_unfilled_index = constructor_index;
6046         }
6047       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6048         {
6049           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6050
6051          /* Do a basic check of initializer size.  Note that vectors
6052             always have a fixed size derived from their type.  */
6053           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6054             {
6055               pedwarn_init ("excess elements in vector initializer");
6056               break;
6057             }
6058
6059           /* Now output the actual element.  */
6060           if (value.value)
6061             output_init_element (value.value, strict_string,
6062                                  elttype, constructor_index, 1);
6063
6064           constructor_index
6065             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6066
6067           if (!value.value)
6068             /* If we are doing the bookkeeping for an element that was
6069                directly output as a constructor, we must update
6070                constructor_unfilled_index.  */
6071             constructor_unfilled_index = constructor_index;
6072         }
6073
6074       /* Handle the sole element allowed in a braced initializer
6075          for a scalar variable.  */
6076       else if (constructor_fields == 0)
6077         {
6078           pedwarn_init ("excess elements in scalar initializer");
6079           break;
6080         }
6081       else
6082         {
6083           if (value.value)
6084             output_init_element (value.value, strict_string,
6085                                  constructor_type, NULL_TREE, 1);
6086           constructor_fields = 0;
6087         }
6088
6089       /* Handle range initializers either at this level or anywhere higher
6090          in the designator stack.  */
6091       if (constructor_range_stack)
6092         {
6093           struct constructor_range_stack *p, *range_stack;
6094           int finish = 0;
6095
6096           range_stack = constructor_range_stack;
6097           constructor_range_stack = 0;
6098           while (constructor_stack != range_stack->stack)
6099             {
6100               if (!constructor_stack->implicit)
6101                 abort ();
6102               process_init_element (pop_init_level (1));
6103             }
6104           for (p = range_stack;
6105                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6106                p = p->prev)
6107             {
6108               if (!constructor_stack->implicit)
6109                 abort ();
6110               process_init_element (pop_init_level (1));
6111             }
6112
6113           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6114           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6115             finish = 1;
6116
6117           while (1)
6118             {
6119               constructor_index = p->index;
6120               constructor_fields = p->fields;
6121               if (finish && p->range_end && p->index == p->range_start)
6122                 {
6123                   finish = 0;
6124                   p->prev = 0;
6125                 }
6126               p = p->next;
6127               if (!p)
6128                 break;
6129               push_init_level (2);
6130               p->stack = constructor_stack;
6131               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6132                 p->index = p->range_start;
6133             }
6134
6135           if (!finish)
6136             constructor_range_stack = range_stack;
6137           continue;
6138         }
6139
6140       break;
6141     }
6142
6143   constructor_range_stack = 0;
6144 }
6145 \f
6146 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6147    (guaranteed to be 'volatile' or null) and ARGS (represented using
6148    an ASM_EXPR node).  */
6149 tree
6150 build_asm_stmt (tree cv_qualifier, tree args)
6151 {
6152   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6153     ASM_VOLATILE_P (args) = 1;
6154   return add_stmt (args);
6155 }
6156
6157 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6158    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6159    SIMPLE indicates whether there was anything at all after the
6160    string in the asm expression -- asm("blah") and asm("blah" : )
6161    are subtly different.  We use a ASM_EXPR node to represent this.  */
6162 tree
6163 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6164                 bool simple)
6165 {
6166   tree tail;
6167   tree args;
6168   int i;
6169   const char *constraint;
6170   bool allows_mem, allows_reg, is_inout;
6171   int ninputs;
6172   int noutputs;
6173
6174   ninputs = list_length (inputs);
6175   noutputs = list_length (outputs);
6176
6177   /* Remove output conversions that change the type but not the mode.  */
6178   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6179     {
6180       tree output = TREE_VALUE (tail);
6181       STRIP_NOPS (output);
6182       TREE_VALUE (tail) = output;
6183       lvalue_or_else (output, "invalid lvalue in asm statement");
6184
6185       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6186
6187       if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
6188                                     &allows_mem, &allows_reg, &is_inout))
6189         {
6190           /* By marking this operand as erroneous, we will not try
6191           to process this operand again in expand_asm_operands.  */
6192           TREE_VALUE (tail) = error_mark_node;
6193           continue;
6194         }
6195
6196       /* If the operand is a DECL that is going to end up in
6197         memory, assume it is addressable.  This is a bit more
6198         conservative than it would ideally be; the exact test is
6199         buried deep in expand_asm_operands and depends on the
6200         DECL_RTL for the OPERAND -- which we don't have at this
6201         point.  */
6202       if (!allows_reg && DECL_P (output))
6203         c_mark_addressable (output);
6204     }
6205
6206   /* Perform default conversions on array and function inputs.
6207      Don't do this for other types as it would screw up operands
6208      expected to be in memory.  */
6209   for (tail = inputs; tail; tail = TREE_CHAIN (tail))
6210     TREE_VALUE (tail) = default_function_array_conversion (TREE_VALUE (tail));
6211
6212   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6213
6214   /* Simple asm statements are treated as volatile.  */
6215   if (simple)
6216     {
6217       ASM_VOLATILE_P (args) = 1;
6218       ASM_INPUT_P (args) = 1;
6219     }
6220   return args;
6221 }
6222 \f
6223 /* Generate a goto statement to LABEL.  */
6224
6225 tree
6226 c_finish_goto_label (tree label)
6227 {
6228   tree decl = lookup_label (label);
6229   if (!decl)
6230     return NULL_TREE;
6231
6232   TREE_USED (decl) = 1;
6233   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6234 }
6235
6236 /* Generate a computed goto statement to EXPR.  */
6237
6238 tree
6239 c_finish_goto_ptr (tree expr)
6240 {
6241   if (pedantic)
6242     pedwarn ("ISO C forbids `goto *expr;'");
6243   expr = convert (ptr_type_node, expr);
6244   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6245 }
6246
6247 /* Generate a C `return' statement.  RETVAL is the expression for what
6248    to return, or a null pointer for `return;' with no value.  */
6249
6250 tree
6251 c_finish_return (tree retval)
6252 {
6253   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6254
6255   if (TREE_THIS_VOLATILE (current_function_decl))
6256     warning ("function declared `noreturn' has a `return' statement");
6257
6258   if (!retval)
6259     {
6260       current_function_returns_null = 1;
6261       if ((warn_return_type || flag_isoc99)
6262           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6263         pedwarn_c99 ("`return' with no value, in function returning non-void");
6264     }
6265   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6266     {
6267       current_function_returns_null = 1;
6268       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6269         pedwarn ("`return' with a value, in function returning void");
6270     }
6271   else
6272     {
6273       tree t = convert_for_assignment (valtype, retval, _("return"),
6274                                        NULL_TREE, NULL_TREE, 0);
6275       tree res = DECL_RESULT (current_function_decl);
6276       tree inner;
6277
6278       current_function_returns_value = 1;
6279       if (t == error_mark_node)
6280         return NULL_TREE;
6281
6282       inner = t = convert (TREE_TYPE (res), t);
6283
6284       /* Strip any conversions, additions, and subtractions, and see if
6285          we are returning the address of a local variable.  Warn if so.  */
6286       while (1)
6287         {
6288           switch (TREE_CODE (inner))
6289             {
6290             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6291             case PLUS_EXPR:
6292               inner = TREE_OPERAND (inner, 0);
6293               continue;
6294
6295             case MINUS_EXPR:
6296               /* If the second operand of the MINUS_EXPR has a pointer
6297                  type (or is converted from it), this may be valid, so
6298                  don't give a warning.  */
6299               {
6300                 tree op1 = TREE_OPERAND (inner, 1);
6301
6302                 while (! POINTER_TYPE_P (TREE_TYPE (op1))
6303                        && (TREE_CODE (op1) == NOP_EXPR
6304                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6305                            || TREE_CODE (op1) == CONVERT_EXPR))
6306                   op1 = TREE_OPERAND (op1, 0);
6307
6308                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6309                   break;
6310
6311                 inner = TREE_OPERAND (inner, 0);
6312                 continue;
6313               }
6314
6315             case ADDR_EXPR:
6316               inner = TREE_OPERAND (inner, 0);
6317
6318               while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r'
6319                      && TREE_CODE (inner) != INDIRECT_REF)
6320                 inner = TREE_OPERAND (inner, 0);
6321
6322               if (DECL_P (inner)
6323                   && ! DECL_EXTERNAL (inner)
6324                   && ! TREE_STATIC (inner)
6325                   && DECL_CONTEXT (inner) == current_function_decl)
6326                 warning ("function returns address of local variable");
6327               break;
6328
6329             default:
6330               break;
6331             }
6332
6333           break;
6334         }
6335
6336       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6337     }
6338
6339   return add_stmt (build_stmt (RETURN_EXPR, retval));
6340 }
6341 \f
6342 struct c_switch {
6343   /* The SWITCH_STMT being built.  */
6344   tree switch_stmt;
6345
6346   /* The original type of the testing expression, ie. before the
6347      default conversion is applied.  */
6348   tree orig_type;
6349
6350   /* A splay-tree mapping the low element of a case range to the high
6351      element, or NULL_TREE if there is no high element.  Used to
6352      determine whether or not a new case label duplicates an old case
6353      label.  We need a tree, rather than simply a hash table, because
6354      of the GNU case range extension.  */
6355   splay_tree cases;
6356
6357   /* The next node on the stack.  */
6358   struct c_switch *next;
6359 };
6360
6361 /* A stack of the currently active switch statements.  The innermost
6362    switch statement is on the top of the stack.  There is no need to
6363    mark the stack for garbage collection because it is only active
6364    during the processing of the body of a function, and we never
6365    collect at that point.  */
6366
6367 struct c_switch *c_switch_stack;
6368
6369 /* Start a C switch statement, testing expression EXP.  Return the new
6370    SWITCH_STMT.  */
6371
6372 tree
6373 c_start_case (tree exp)
6374 {
6375   enum tree_code code;
6376   tree type, orig_type = error_mark_node;
6377   struct c_switch *cs;
6378
6379   if (exp != error_mark_node)
6380     {
6381       code = TREE_CODE (TREE_TYPE (exp));
6382       orig_type = TREE_TYPE (exp);
6383
6384       if (! INTEGRAL_TYPE_P (orig_type)
6385           && code != ERROR_MARK)
6386         {
6387           error ("switch quantity not an integer");
6388           exp = integer_zero_node;
6389         }
6390       else
6391         {
6392           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6393
6394           if (warn_traditional && !in_system_header
6395               && (type == long_integer_type_node
6396                   || type == long_unsigned_type_node))
6397             warning ("`long' switch expression not converted to `int' in ISO C");
6398
6399           exp = default_conversion (exp);
6400           type = TREE_TYPE (exp);
6401         }
6402     }
6403
6404   /* Add this new SWITCH_STMT to the stack.  */
6405   cs = XNEW (struct c_switch);
6406   cs->switch_stmt = build_stmt ((enum tree_code) SWITCH_STMT, exp, NULL_TREE,
6407                                 orig_type);
6408   cs->orig_type = orig_type;
6409   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6410   cs->next = c_switch_stack;
6411   c_switch_stack = cs;
6412
6413   return add_stmt (cs->switch_stmt);
6414 }
6415
6416 /* Process a case label.  */
6417
6418 tree
6419 do_case (tree low_value, tree high_value)
6420 {
6421   tree label = NULL_TREE;
6422
6423   if (c_switch_stack)
6424     {
6425       label = c_add_case_label (c_switch_stack->cases,
6426                                 SWITCH_COND (c_switch_stack->switch_stmt),
6427                                 c_switch_stack->orig_type,
6428                                 low_value, high_value);
6429       if (label == error_mark_node)
6430         label = NULL_TREE;
6431     }
6432   else if (low_value)
6433     error ("case label not within a switch statement");
6434   else
6435     error ("`default' label not within a switch statement");
6436
6437   return label;
6438 }
6439
6440 /* Finish the switch statement.  */
6441
6442 void
6443 c_finish_case (tree body)
6444 {
6445   struct c_switch *cs = c_switch_stack;
6446
6447   SWITCH_BODY (cs->switch_stmt) = body;
6448
6449   /* Emit warnings as needed.  */
6450   c_do_switch_warnings (cs->cases, cs->switch_stmt);
6451
6452   /* Pop the stack.  */
6453   c_switch_stack = cs->next;
6454   splay_tree_delete (cs->cases);
6455   XDELETE (cs);
6456 }
6457 \f
6458 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
6459    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
6460    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
6461    statement, and was not surrounded with parenthesis.  */
6462
6463 void
6464 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
6465                   tree else_block, bool nested_if)
6466 {
6467   tree stmt;
6468
6469   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
6470   if (warn_parentheses && nested_if && else_block == NULL)
6471     {
6472       tree inner_if = then_block;
6473
6474       /* We know from the grammar productions that there is an IF nested
6475          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
6476          it might not be exactly THEN_BLOCK, but should be the last
6477          non-container statement within.  */
6478       while (1)
6479         switch (TREE_CODE (inner_if))
6480           {
6481           case COND_EXPR:
6482             goto found;
6483           case BIND_EXPR:
6484             inner_if = BIND_EXPR_BODY (inner_if);
6485             break;
6486           case STATEMENT_LIST:
6487             inner_if = expr_last (then_block);
6488             break;
6489           case TRY_FINALLY_EXPR:
6490           case TRY_CATCH_EXPR:
6491             inner_if = TREE_OPERAND (inner_if, 0);
6492             break;
6493           default:
6494             abort ();
6495           }
6496     found:
6497
6498       if (COND_EXPR_ELSE (inner_if))
6499          warning ("%Hsuggest explicit braces to avoid ambiguous `else'",
6500                   &if_locus);
6501     }
6502
6503   /* Diagnose ";" via the special empty statement node that we create.  */
6504   if (extra_warnings)
6505     {
6506       if (TREE_CODE (then_block) == NOP_EXPR && !TREE_TYPE (then_block))
6507         {
6508           if (!else_block)
6509             warning ("%Hempty body in an if-statement",
6510                      EXPR_LOCUS (then_block));
6511           then_block = alloc_stmt_list ();
6512         }
6513       if (else_block
6514           && TREE_CODE (else_block) == NOP_EXPR
6515           && !TREE_TYPE (else_block))
6516         {
6517           warning ("%Hempty body in an else-statement",
6518                    EXPR_LOCUS (else_block));
6519           else_block = alloc_stmt_list ();
6520         }
6521     }
6522
6523   stmt = build3 (COND_EXPR, NULL_TREE, cond, then_block, else_block);
6524   SET_EXPR_LOCATION (stmt, if_locus);
6525   add_stmt (stmt);
6526 }
6527
6528 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
6529    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
6530    is false for DO loops.  INCR is the FOR increment expression.  BODY is
6531    the statement controlled by the loop.  BLAB is the break label.  CLAB is
6532    the continue label.  Everything is allowed to be NULL.  */
6533
6534 void
6535 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
6536                tree blab, tree clab, bool cond_is_first)
6537 {
6538   tree entry = NULL, exit = NULL, t;
6539
6540   /* Detect do { ... } while (0) and don't generate loop construct.  */
6541   if (cond && !cond_is_first && integer_zerop (cond))
6542     cond = NULL;
6543   if (cond_is_first || cond)
6544     {
6545       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6546
6547       /* If we have an exit condition, then we build an IF with gotos either
6548          out of the loop, or to the top of it.  If there's no exit condition,
6549          then we just build a jump back to the top.  */
6550       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
6551
6552       if (cond)
6553         {
6554           /* Canonicalize the loop condition to the end.  This means
6555              generating a branch to the loop condition.  Reuse the
6556              continue label, if possible.  */
6557           if (cond_is_first)
6558             {
6559               if (incr || !clab)
6560                 {
6561                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
6562                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
6563                 }
6564               else
6565                 t = build1 (GOTO_EXPR, void_type_node, clab);
6566               SET_EXPR_LOCATION (t, start_locus);
6567               add_stmt (t);
6568             }
6569
6570           t = build_and_jump (&blab);
6571           exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
6572           exit = fold (exit);
6573           if (cond_is_first)
6574             SET_EXPR_LOCATION (exit, start_locus);
6575           else
6576             SET_EXPR_LOCATION (exit, input_location);
6577         }
6578
6579       add_stmt (top);
6580     }
6581
6582   if (body)
6583     add_stmt (body);
6584   if (clab)
6585     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
6586   if (incr)
6587     add_stmt (incr);
6588   if (entry)
6589     add_stmt (entry);
6590   if (exit)
6591     add_stmt (exit);
6592   if (blab)
6593     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
6594 }
6595
6596 tree
6597 c_finish_bc_stmt (tree *label_p, bool is_break)
6598 {
6599   tree label = *label_p;
6600
6601   if (!label)
6602     *label_p = label = create_artificial_label ();
6603   else if (TREE_CODE (label) != LABEL_DECL)
6604     {
6605       if (is_break)
6606         error ("break statement not within loop or switch");
6607       else
6608         error ("continue statement not within a loop");
6609       return NULL_TREE;
6610     }
6611
6612   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
6613 }
6614
6615 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
6616
6617 static void
6618 emit_side_effect_warnings (tree expr)
6619 {
6620   if (expr == error_mark_node)
6621     ;
6622   else if (!TREE_SIDE_EFFECTS (expr))
6623     {
6624       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
6625         warning ("%Hstatement with no effect",
6626                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
6627     }
6628   else if (warn_unused_value)
6629     warn_if_unused_value (expr, input_location);
6630 }
6631
6632 /* Process an expression as if it were a complete statement.  Emit
6633    diagnostics, but do not call ADD_STMT.  */
6634
6635 tree
6636 c_process_expr_stmt (tree expr)
6637 {
6638   if (!expr)
6639     return NULL_TREE;
6640
6641   /* Do default conversion if safe and possibly important,
6642      in case within ({...}).  */
6643   if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
6644        && (flag_isoc99 || lvalue_p (expr)))
6645       || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE)
6646     expr = default_conversion (expr);
6647
6648   if (warn_sequence_point)
6649     verify_sequence_points (expr);
6650
6651   if (TREE_TYPE (expr) != error_mark_node
6652       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
6653       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
6654     error ("expression statement has incomplete type");
6655
6656   /* If we're not processing a statement expression, warn about unused values.
6657      Warnings for statement expressions will be emitted later, once we figure
6658      out which is the result.  */
6659   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6660       && (extra_warnings || warn_unused_value))
6661     emit_side_effect_warnings (expr);
6662
6663   /* If the expression is not of a type to which we cannot assign a line
6664      number, wrap the thing in a no-op NOP_EXPR.  */
6665   if (DECL_P (expr) || TREE_CODE_CLASS (TREE_CODE (expr)) == 'c')
6666     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
6667
6668   if (EXPR_P (expr))
6669     SET_EXPR_LOCATION (expr, input_location);
6670
6671   return expr;
6672 }
6673
6674 /* Emit an expression as a statement.  */
6675
6676 tree
6677 c_finish_expr_stmt (tree expr)
6678 {
6679   if (expr)
6680     return add_stmt (c_process_expr_stmt (expr));
6681   else
6682     return NULL;
6683 }
6684
6685 /* Do the opposite and emit a statement as an expression.  To begin,
6686    create a new binding level and return it.  */
6687
6688 tree
6689 c_begin_stmt_expr (void)
6690 {
6691   tree ret;
6692
6693   /* We must force a BLOCK for this level so that, if it is not expanded
6694      later, there is a way to turn off the entire subtree of blocks that
6695      are contained in it.  */
6696   keep_next_level ();
6697   ret = c_begin_compound_stmt (true);
6698
6699   /* Mark the current statement list as belonging to a statement list.  */
6700   STATEMENT_LIST_STMT_EXPR (ret) = 1;
6701
6702   return ret;
6703 }
6704
6705 tree
6706 c_finish_stmt_expr (tree body)
6707 {
6708   tree last, type, tmp, val;
6709   tree *last_p;
6710
6711   body = c_end_compound_stmt (body, true);
6712
6713   /* Locate the last statement in BODY.  See c_end_compound_stmt
6714      about always returning a BIND_EXPR.  */
6715   last_p = &BIND_EXPR_BODY (body);
6716   last = BIND_EXPR_BODY (body);
6717
6718  continue_searching:
6719   if (TREE_CODE (last) == STATEMENT_LIST)
6720     {
6721       tree_stmt_iterator i;
6722
6723       /* This can happen with degenerate cases like ({ }).  No value.  */
6724       if (!TREE_SIDE_EFFECTS (last))
6725         return body;
6726
6727       /* If we're supposed to generate side effects warnings, process
6728          all of the statements except the last.  */
6729       if (extra_warnings || warn_unused_value)
6730         {
6731           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
6732             emit_side_effect_warnings (tsi_stmt (i));
6733         }
6734       else
6735         i = tsi_last (last);
6736       last_p = tsi_stmt_ptr (i);
6737       last = *last_p;
6738     }
6739
6740   /* If the end of the list is exception related, then the list was split
6741      by a call to push_cleanup.  Continue searching.  */
6742   if (TREE_CODE (last) == TRY_FINALLY_EXPR
6743       || TREE_CODE (last) == TRY_CATCH_EXPR)
6744     {
6745       last_p = &TREE_OPERAND (last, 0);
6746       last = *last_p;
6747       goto continue_searching;
6748     }
6749
6750   /* In the case that the BIND_EXPR is not necessary, return the
6751      expression out from inside it.  */
6752   if (last == error_mark_node
6753       || (last == BIND_EXPR_BODY (body)
6754           && BIND_EXPR_VARS (body) == NULL))
6755     return last;
6756
6757   /* Extract the type of said expression.  */
6758   type = TREE_TYPE (last);
6759
6760   /* If we're not returning a value at all, then the BIND_EXPR that
6761      we already have is a fine expression to return.  */
6762   if (!type || VOID_TYPE_P (type))
6763     return body;
6764
6765   /* Now that we've located the expression containing the value, it seems
6766      silly to make voidify_wrapper_expr repeat the process.  Create a
6767      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
6768   tmp = create_tmp_var_raw (type, NULL);
6769
6770   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
6771      tree_expr_nonnegative_p giving up immediately.  */
6772   val = last;
6773   if (TREE_CODE (val) == NOP_EXPR
6774       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
6775     val = TREE_OPERAND (val, 0);
6776
6777   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
6778   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
6779
6780   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
6781 }
6782 \f
6783 /* Begin and end compound statements.  This is as simple as pushing
6784    and popping new statement lists from the tree.  */
6785
6786 tree
6787 c_begin_compound_stmt (bool do_scope)
6788 {
6789   tree stmt = push_stmt_list ();
6790   if (do_scope)
6791     push_scope ();
6792   return stmt;
6793 }
6794
6795 tree
6796 c_end_compound_stmt (tree stmt, bool do_scope)
6797 {
6798   tree block = NULL;
6799
6800   if (do_scope)
6801     {
6802       if (c_dialect_objc ())
6803         objc_clear_super_receiver ();
6804       block = pop_scope ();
6805     }
6806
6807   stmt = pop_stmt_list (stmt);
6808   stmt = c_build_bind_expr (block, stmt);
6809
6810   /* If this compound statement is nested immediately inside a statement
6811      expression, then force a BIND_EXPR to be created.  Otherwise we'll
6812      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
6813      STATEMENT_LISTs merge, and thus we can lose track of what statement
6814      was really last.  */
6815   if (cur_stmt_list
6816       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6817       && TREE_CODE (stmt) != BIND_EXPR)
6818     {
6819       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
6820       TREE_SIDE_EFFECTS (stmt) = 1;
6821     }
6822
6823   return stmt;
6824 }
6825
6826 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
6827    when the current scope is exited.  EH_ONLY is true when this is not
6828    meant to apply to normal control flow transfer.  */
6829
6830 void
6831 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
6832 {
6833   enum tree_code code;
6834   tree stmt, list;
6835   bool stmt_expr;
6836
6837   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
6838   stmt = build_stmt (code, NULL, cleanup);
6839   add_stmt (stmt);
6840   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
6841   list = push_stmt_list ();
6842   TREE_OPERAND (stmt, 0) = list;
6843   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
6844 }
6845 \f
6846 /* Build a binary-operation expression without default conversions.
6847    CODE is the kind of expression to build.
6848    This function differs from `build' in several ways:
6849    the data type of the result is computed and recorded in it,
6850    warnings are generated if arg data types are invalid,
6851    special handling for addition and subtraction of pointers is known,
6852    and some optimization is done (operations on narrow ints
6853    are done in the narrower type when that gives the same result).
6854    Constant folding is also done before the result is returned.
6855
6856    Note that the operands will never have enumeral types, or function
6857    or array types, because either they will have the default conversions
6858    performed or they have both just been converted to some other type in which
6859    the arithmetic is to be done.  */
6860
6861 tree
6862 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
6863                  int convert_p)
6864 {
6865   tree type0, type1;
6866   enum tree_code code0, code1;
6867   tree op0, op1;
6868
6869   /* Expression code to give to the expression when it is built.
6870      Normally this is CODE, which is what the caller asked for,
6871      but in some special cases we change it.  */
6872   enum tree_code resultcode = code;
6873
6874   /* Data type in which the computation is to be performed.
6875      In the simplest cases this is the common type of the arguments.  */
6876   tree result_type = NULL;
6877
6878   /* Nonzero means operands have already been type-converted
6879      in whatever way is necessary.
6880      Zero means they need to be converted to RESULT_TYPE.  */
6881   int converted = 0;
6882
6883   /* Nonzero means create the expression with this type, rather than
6884      RESULT_TYPE.  */
6885   tree build_type = 0;
6886
6887   /* Nonzero means after finally constructing the expression
6888      convert it to this type.  */
6889   tree final_type = 0;
6890
6891   /* Nonzero if this is an operation like MIN or MAX which can
6892      safely be computed in short if both args are promoted shorts.
6893      Also implies COMMON.
6894      -1 indicates a bitwise operation; this makes a difference
6895      in the exact conditions for when it is safe to do the operation
6896      in a narrower mode.  */
6897   int shorten = 0;
6898
6899   /* Nonzero if this is a comparison operation;
6900      if both args are promoted shorts, compare the original shorts.
6901      Also implies COMMON.  */
6902   int short_compare = 0;
6903
6904   /* Nonzero if this is a right-shift operation, which can be computed on the
6905      original short and then promoted if the operand is a promoted short.  */
6906   int short_shift = 0;
6907
6908   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
6909   int common = 0;
6910
6911   if (convert_p)
6912     {
6913       op0 = default_conversion (orig_op0);
6914       op1 = default_conversion (orig_op1);
6915     }
6916   else
6917     {
6918       op0 = orig_op0;
6919       op1 = orig_op1;
6920     }
6921
6922   type0 = TREE_TYPE (op0);
6923   type1 = TREE_TYPE (op1);
6924
6925   /* The expression codes of the data types of the arguments tell us
6926      whether the arguments are integers, floating, pointers, etc.  */
6927   code0 = TREE_CODE (type0);
6928   code1 = TREE_CODE (type1);
6929
6930   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
6931   STRIP_TYPE_NOPS (op0);
6932   STRIP_TYPE_NOPS (op1);
6933
6934   /* If an error was already reported for one of the arguments,
6935      avoid reporting another error.  */
6936
6937   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
6938     return error_mark_node;
6939
6940   switch (code)
6941     {
6942     case PLUS_EXPR:
6943       /* Handle the pointer + int case.  */
6944       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6945         return pointer_int_sum (PLUS_EXPR, op0, op1);
6946       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
6947         return pointer_int_sum (PLUS_EXPR, op1, op0);
6948       else
6949         common = 1;
6950       break;
6951
6952     case MINUS_EXPR:
6953       /* Subtraction of two similar pointers.
6954          We must subtract them as integers, then divide by object size.  */
6955       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
6956           && comp_target_types (type0, type1, 1))
6957         return pointer_diff (op0, op1);
6958       /* Handle pointer minus int.  Just like pointer plus int.  */
6959       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6960         return pointer_int_sum (MINUS_EXPR, op0, op1);
6961       else
6962         common = 1;
6963       break;
6964
6965     case MULT_EXPR:
6966       common = 1;
6967       break;
6968
6969     case TRUNC_DIV_EXPR:
6970     case CEIL_DIV_EXPR:
6971     case FLOOR_DIV_EXPR:
6972     case ROUND_DIV_EXPR:
6973     case EXACT_DIV_EXPR:
6974       /* Floating point division by zero is a legitimate way to obtain
6975          infinities and NaNs.  */
6976       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6977         warning ("division by zero");
6978
6979       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
6980            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6981           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
6982               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
6983         {
6984           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6985             code0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
6986           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
6987             code1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
6988
6989           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
6990             resultcode = RDIV_EXPR;
6991           else
6992             /* Although it would be tempting to shorten always here, that
6993                loses on some targets, since the modulo instruction is
6994                undefined if the quotient can't be represented in the
6995                computation mode.  We shorten only if unsigned or if
6996                dividing by something we know != -1.  */
6997             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
6998                        || (TREE_CODE (op1) == INTEGER_CST
6999                            && ! integer_all_onesp (op1)));
7000           common = 1;
7001         }
7002       break;
7003
7004     case BIT_AND_EXPR:
7005     case BIT_IOR_EXPR:
7006     case BIT_XOR_EXPR:
7007       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7008         shorten = -1;
7009       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7010         common = 1;
7011       break;
7012
7013     case TRUNC_MOD_EXPR:
7014     case FLOOR_MOD_EXPR:
7015       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
7016         warning ("division by zero");
7017
7018       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7019         {
7020           /* Although it would be tempting to shorten always here, that loses
7021              on some targets, since the modulo instruction is undefined if the
7022              quotient can't be represented in the computation mode.  We shorten
7023              only if unsigned or if dividing by something we know != -1.  */
7024           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7025                      || (TREE_CODE (op1) == INTEGER_CST
7026                          && ! integer_all_onesp (op1)));
7027           common = 1;
7028         }
7029       break;
7030
7031     case TRUTH_ANDIF_EXPR:
7032     case TRUTH_ORIF_EXPR:
7033     case TRUTH_AND_EXPR:
7034     case TRUTH_OR_EXPR:
7035     case TRUTH_XOR_EXPR:
7036       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7037            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7038           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7039               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7040         {
7041           /* Result of these operations is always an int,
7042              but that does not mean the operands should be
7043              converted to ints!  */
7044           result_type = integer_type_node;
7045           op0 = lang_hooks.truthvalue_conversion (op0);
7046           op1 = lang_hooks.truthvalue_conversion (op1);
7047           converted = 1;
7048         }
7049       break;
7050
7051       /* Shift operations: result has same type as first operand;
7052          always convert second operand to int.
7053          Also set SHORT_SHIFT if shifting rightward.  */
7054
7055     case RSHIFT_EXPR:
7056       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7057         {
7058           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7059             {
7060               if (tree_int_cst_sgn (op1) < 0)
7061                 warning ("right shift count is negative");
7062               else
7063                 {
7064                   if (! integer_zerop (op1))
7065                     short_shift = 1;
7066
7067                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7068                     warning ("right shift count >= width of type");
7069                 }
7070             }
7071
7072           /* Use the type of the value to be shifted.  */
7073           result_type = type0;
7074           /* Convert the shift-count to an integer, regardless of size
7075              of value being shifted.  */
7076           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7077             op1 = convert (integer_type_node, op1);
7078           /* Avoid converting op1 to result_type later.  */
7079           converted = 1;
7080         }
7081       break;
7082
7083     case LSHIFT_EXPR:
7084       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7085         {
7086           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7087             {
7088               if (tree_int_cst_sgn (op1) < 0)
7089                 warning ("left shift count is negative");
7090
7091               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7092                 warning ("left shift count >= width of type");
7093             }
7094
7095           /* Use the type of the value to be shifted.  */
7096           result_type = type0;
7097           /* Convert the shift-count to an integer, regardless of size
7098              of value being shifted.  */
7099           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7100             op1 = convert (integer_type_node, op1);
7101           /* Avoid converting op1 to result_type later.  */
7102           converted = 1;
7103         }
7104       break;
7105
7106     case RROTATE_EXPR:
7107     case LROTATE_EXPR:
7108       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7109         {
7110           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7111             {
7112               if (tree_int_cst_sgn (op1) < 0)
7113                 warning ("shift count is negative");
7114               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7115                 warning ("shift count >= width of type");
7116             }
7117
7118           /* Use the type of the value to be shifted.  */
7119           result_type = type0;
7120           /* Convert the shift-count to an integer, regardless of size
7121              of value being shifted.  */
7122           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7123             op1 = convert (integer_type_node, op1);
7124           /* Avoid converting op1 to result_type later.  */
7125           converted = 1;
7126         }
7127       break;
7128
7129     case EQ_EXPR:
7130     case NE_EXPR:
7131       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
7132         warning ("comparing floating point with == or != is unsafe");
7133       /* Result of comparison is always int,
7134          but don't convert the args to int!  */
7135       build_type = integer_type_node;
7136       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7137            || code0 == COMPLEX_TYPE)
7138           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7139               || code1 == COMPLEX_TYPE))
7140         short_compare = 1;
7141       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7142         {
7143           tree tt0 = TREE_TYPE (type0);
7144           tree tt1 = TREE_TYPE (type1);
7145           /* Anything compares with void *.  void * compares with anything.
7146              Otherwise, the targets must be compatible
7147              and both must be object or both incomplete.  */
7148           if (comp_target_types (type0, type1, 1))
7149             result_type = common_pointer_type (type0, type1);
7150           else if (VOID_TYPE_P (tt0))
7151             {
7152               /* op0 != orig_op0 detects the case of something
7153                  whose value is 0 but which isn't a valid null ptr const.  */
7154               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7155                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7156                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7157             }
7158           else if (VOID_TYPE_P (tt1))
7159             {
7160               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7161                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7162                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7163             }
7164           else
7165             pedwarn ("comparison of distinct pointer types lacks a cast");
7166
7167           if (result_type == NULL_TREE)
7168             result_type = ptr_type_node;
7169         }
7170       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7171                && integer_zerop (op1))
7172         result_type = type0;
7173       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7174                && integer_zerop (op0))
7175         result_type = type1;
7176       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7177         {
7178           result_type = type0;
7179           pedwarn ("comparison between pointer and integer");
7180         }
7181       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7182         {
7183           result_type = type1;
7184           pedwarn ("comparison between pointer and integer");
7185         }
7186       break;
7187
7188     case MAX_EXPR:
7189     case MIN_EXPR:
7190       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7191           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7192         shorten = 1;
7193       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7194         {
7195           if (comp_target_types (type0, type1, 1))
7196             {
7197               result_type = common_pointer_type (type0, type1);
7198               if (pedantic
7199                   && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7200                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7201             }
7202           else
7203             {
7204               result_type = ptr_type_node;
7205               pedwarn ("comparison of distinct pointer types lacks a cast");
7206             }
7207         }
7208       break;
7209
7210     case LE_EXPR:
7211     case GE_EXPR:
7212     case LT_EXPR:
7213     case GT_EXPR:
7214       build_type = integer_type_node;
7215       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7216           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7217         short_compare = 1;
7218       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7219         {
7220           if (comp_target_types (type0, type1, 1))
7221             {
7222               result_type = common_pointer_type (type0, type1);
7223               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7224                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7225                 pedwarn ("comparison of complete and incomplete pointers");
7226               else if (pedantic
7227                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7228                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7229             }
7230           else
7231             {
7232               result_type = ptr_type_node;
7233               pedwarn ("comparison of distinct pointer types lacks a cast");
7234             }
7235         }
7236       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7237                && integer_zerop (op1))
7238         {
7239           result_type = type0;
7240           if (pedantic || extra_warnings)
7241             pedwarn ("ordered comparison of pointer with integer zero");
7242         }
7243       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7244                && integer_zerop (op0))
7245         {
7246           result_type = type1;
7247           if (pedantic)
7248             pedwarn ("ordered comparison of pointer with integer zero");
7249         }
7250       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7251         {
7252           result_type = type0;
7253           pedwarn ("comparison between pointer and integer");
7254         }
7255       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7256         {
7257           result_type = type1;
7258           pedwarn ("comparison between pointer and integer");
7259         }
7260       break;
7261
7262     case UNORDERED_EXPR:
7263     case ORDERED_EXPR:
7264     case UNLT_EXPR:
7265     case UNLE_EXPR:
7266     case UNGT_EXPR:
7267     case UNGE_EXPR:
7268     case UNEQ_EXPR:
7269     case LTGT_EXPR:
7270       build_type = integer_type_node;
7271       if (code0 != REAL_TYPE || code1 != REAL_TYPE)
7272         {
7273           error ("unordered comparison on non-floating point argument");
7274           return error_mark_node;
7275         }
7276       common = 1;
7277       break;
7278
7279     default:
7280       break;
7281     }
7282
7283   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7284     return error_mark_node;
7285
7286   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7287        || code0 == VECTOR_TYPE)
7288       &&
7289       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7290        || code1 == VECTOR_TYPE))
7291     {
7292       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7293
7294       if (shorten || common || short_compare)
7295         result_type = common_type (type0, type1);
7296
7297       /* For certain operations (which identify themselves by shorten != 0)
7298          if both args were extended from the same smaller type,
7299          do the arithmetic in that type and then extend.
7300
7301          shorten !=0 and !=1 indicates a bitwise operation.
7302          For them, this optimization is safe only if
7303          both args are zero-extended or both are sign-extended.
7304          Otherwise, we might change the result.
7305          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7306          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7307
7308       if (shorten && none_complex)
7309         {
7310           int unsigned0, unsigned1;
7311           tree arg0 = get_narrower (op0, &unsigned0);
7312           tree arg1 = get_narrower (op1, &unsigned1);
7313           /* UNS is 1 if the operation to be done is an unsigned one.  */
7314           int uns = TYPE_UNSIGNED (result_type);
7315           tree type;
7316
7317           final_type = result_type;
7318
7319           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7320              but it *requires* conversion to FINAL_TYPE.  */
7321
7322           if ((TYPE_PRECISION (TREE_TYPE (op0))
7323                == TYPE_PRECISION (TREE_TYPE (arg0)))
7324               && TREE_TYPE (op0) != final_type)
7325             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7326           if ((TYPE_PRECISION (TREE_TYPE (op1))
7327                == TYPE_PRECISION (TREE_TYPE (arg1)))
7328               && TREE_TYPE (op1) != final_type)
7329             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7330
7331           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7332
7333           /* For bitwise operations, signedness of nominal type
7334              does not matter.  Consider only how operands were extended.  */
7335           if (shorten == -1)
7336             uns = unsigned0;
7337
7338           /* Note that in all three cases below we refrain from optimizing
7339              an unsigned operation on sign-extended args.
7340              That would not be valid.  */
7341
7342           /* Both args variable: if both extended in same way
7343              from same width, do it in that width.
7344              Do it unsigned if args were zero-extended.  */
7345           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7346                < TYPE_PRECISION (result_type))
7347               && (TYPE_PRECISION (TREE_TYPE (arg1))
7348                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7349               && unsigned0 == unsigned1
7350               && (unsigned0 || !uns))
7351             result_type
7352               = c_common_signed_or_unsigned_type
7353               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7354           else if (TREE_CODE (arg0) == INTEGER_CST
7355                    && (unsigned1 || !uns)
7356                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7357                        < TYPE_PRECISION (result_type))
7358                    && (type
7359                        = c_common_signed_or_unsigned_type (unsigned1,
7360                                                            TREE_TYPE (arg1)),
7361                        int_fits_type_p (arg0, type)))
7362             result_type = type;
7363           else if (TREE_CODE (arg1) == INTEGER_CST
7364                    && (unsigned0 || !uns)
7365                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7366                        < TYPE_PRECISION (result_type))
7367                    && (type
7368                        = c_common_signed_or_unsigned_type (unsigned0,
7369                                                            TREE_TYPE (arg0)),
7370                        int_fits_type_p (arg1, type)))
7371             result_type = type;
7372         }
7373
7374       /* Shifts can be shortened if shifting right.  */
7375
7376       if (short_shift)
7377         {
7378           int unsigned_arg;
7379           tree arg0 = get_narrower (op0, &unsigned_arg);
7380
7381           final_type = result_type;
7382
7383           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7384             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7385
7386           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7387               /* We can shorten only if the shift count is less than the
7388                  number of bits in the smaller type size.  */
7389               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7390               /* We cannot drop an unsigned shift after sign-extension.  */
7391               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7392             {
7393               /* Do an unsigned shift if the operand was zero-extended.  */
7394               result_type
7395                 = c_common_signed_or_unsigned_type (unsigned_arg,
7396                                                     TREE_TYPE (arg0));
7397               /* Convert value-to-be-shifted to that type.  */
7398               if (TREE_TYPE (op0) != result_type)
7399                 op0 = convert (result_type, op0);
7400               converted = 1;
7401             }
7402         }
7403
7404       /* Comparison operations are shortened too but differently.
7405          They identify themselves by setting short_compare = 1.  */
7406
7407       if (short_compare)
7408         {
7409           /* Don't write &op0, etc., because that would prevent op0
7410              from being kept in a register.
7411              Instead, make copies of the our local variables and
7412              pass the copies by reference, then copy them back afterward.  */
7413           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7414           enum tree_code xresultcode = resultcode;
7415           tree val
7416             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7417
7418           if (val != 0)
7419             return val;
7420
7421           op0 = xop0, op1 = xop1;
7422           converted = 1;
7423           resultcode = xresultcode;
7424
7425           if (warn_sign_compare && skip_evaluation == 0)
7426             {
7427               int op0_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7428               int op1_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7429               int unsignedp0, unsignedp1;
7430               tree primop0 = get_narrower (op0, &unsignedp0);
7431               tree primop1 = get_narrower (op1, &unsignedp1);
7432
7433               xop0 = orig_op0;
7434               xop1 = orig_op1;
7435               STRIP_TYPE_NOPS (xop0);
7436               STRIP_TYPE_NOPS (xop1);
7437
7438               /* Give warnings for comparisons between signed and unsigned
7439                  quantities that may fail.
7440
7441                  Do the checking based on the original operand trees, so that
7442                  casts will be considered, but default promotions won't be.
7443
7444                  Do not warn if the comparison is being done in a signed type,
7445                  since the signed type will only be chosen if it can represent
7446                  all the values of the unsigned type.  */
7447               if (! TYPE_UNSIGNED (result_type))
7448                 /* OK */;
7449               /* Do not warn if both operands are the same signedness.  */
7450               else if (op0_signed == op1_signed)
7451                 /* OK */;
7452               else
7453                 {
7454                   tree sop, uop;
7455
7456                   if (op0_signed)
7457                     sop = xop0, uop = xop1;
7458                   else
7459                     sop = xop1, uop = xop0;
7460
7461                   /* Do not warn if the signed quantity is an
7462                      unsuffixed integer literal (or some static
7463                      constant expression involving such literals or a
7464                      conditional expression involving such literals)
7465                      and it is non-negative.  */
7466                   if (tree_expr_nonnegative_p (sop))
7467                     /* OK */;
7468                   /* Do not warn if the comparison is an equality operation,
7469                      the unsigned quantity is an integral constant, and it
7470                      would fit in the result if the result were signed.  */
7471                   else if (TREE_CODE (uop) == INTEGER_CST
7472                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7473                            && int_fits_type_p
7474                            (uop, c_common_signed_type (result_type)))
7475                     /* OK */;
7476                   /* Do not warn if the unsigned quantity is an enumeration
7477                      constant and its maximum value would fit in the result
7478                      if the result were signed.  */
7479                   else if (TREE_CODE (uop) == INTEGER_CST
7480                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7481                            && int_fits_type_p
7482                            (TYPE_MAX_VALUE (TREE_TYPE(uop)),
7483                             c_common_signed_type (result_type)))
7484                     /* OK */;
7485                   else
7486                     warning ("comparison between signed and unsigned");
7487                 }
7488
7489               /* Warn if two unsigned values are being compared in a size
7490                  larger than their original size, and one (and only one) is the
7491                  result of a `~' operator.  This comparison will always fail.
7492
7493                  Also warn if one operand is a constant, and the constant
7494                  does not have all bits set that are set in the ~ operand
7495                  when it is extended.  */
7496
7497               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7498                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7499                 {
7500                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7501                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7502                                             &unsignedp0);
7503                   else
7504                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7505                                             &unsignedp1);
7506
7507                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7508                     {
7509                       tree primop;
7510                       HOST_WIDE_INT constant, mask;
7511                       int unsignedp, bits;
7512
7513                       if (host_integerp (primop0, 0))
7514                         {
7515                           primop = primop1;
7516                           unsignedp = unsignedp1;
7517                           constant = tree_low_cst (primop0, 0);
7518                         }
7519                       else
7520                         {
7521                           primop = primop0;
7522                           unsignedp = unsignedp0;
7523                           constant = tree_low_cst (primop1, 0);
7524                         }
7525
7526                       bits = TYPE_PRECISION (TREE_TYPE (primop));
7527                       if (bits < TYPE_PRECISION (result_type)
7528                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
7529                         {
7530                           mask = (~ (HOST_WIDE_INT) 0) << bits;
7531                           if ((mask & constant) != mask)
7532                             warning ("comparison of promoted ~unsigned with constant");
7533                         }
7534                     }
7535                   else if (unsignedp0 && unsignedp1
7536                            && (TYPE_PRECISION (TREE_TYPE (primop0))
7537                                < TYPE_PRECISION (result_type))
7538                            && (TYPE_PRECISION (TREE_TYPE (primop1))
7539                                < TYPE_PRECISION (result_type)))
7540                     warning ("comparison of promoted ~unsigned with unsigned");
7541                 }
7542             }
7543         }
7544     }
7545
7546   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7547      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7548      Then the expression will be built.
7549      It will be given type FINAL_TYPE if that is nonzero;
7550      otherwise, it will be given type RESULT_TYPE.  */
7551
7552   if (!result_type)
7553     {
7554       binary_op_error (code);
7555       return error_mark_node;
7556     }
7557
7558   if (! converted)
7559     {
7560       if (TREE_TYPE (op0) != result_type)
7561         op0 = convert (result_type, op0);
7562       if (TREE_TYPE (op1) != result_type)
7563         op1 = convert (result_type, op1);
7564
7565       /* This can happen if one operand has a vector type, and the other
7566          has a different type.  */
7567       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
7568         return error_mark_node;
7569     }
7570
7571   if (build_type == NULL_TREE)
7572     build_type = result_type;
7573
7574   {
7575     tree result = build2 (resultcode, build_type, op0, op1);
7576
7577     /* Treat expressions in initializers specially as they can't trap.  */
7578     result = require_constant_value ? fold_initializer (result)
7579                                     : fold (result);
7580
7581     if (final_type != 0)
7582       result = convert (final_type, result);
7583     return result;
7584   }
7585 }
7586
7587 /* Build the result of __builtin_offsetof.  TYPE is the first argument to
7588    offsetof, i.e. a type.  LIST is a tree_list that encodes component and
7589    array references; PURPOSE is set for the former and VALUE is set for
7590    the later.  */
7591
7592 tree
7593 build_offsetof (tree type, tree list)
7594 {
7595   tree t;
7596
7597   /* Build "*(type *)0".  */
7598   t = convert (build_pointer_type (type), null_pointer_node);
7599   t = build_indirect_ref (t, "");
7600
7601   /* Build COMPONENT and ARRAY_REF expressions as needed.  */
7602   for (list = nreverse (list); list ; list = TREE_CHAIN (list))
7603     if (TREE_PURPOSE (list))
7604       t = build_component_ref (t, TREE_PURPOSE (list));
7605     else
7606       t = build_array_ref (t, TREE_VALUE (list));
7607
7608   /* Finalize the offsetof expression.  For now all we need to do is take
7609      the address of the expression we created, and cast that to an integer
7610      type; this mirrors the traditional macro implementation of offsetof.  */
7611   t = build_unary_op (ADDR_EXPR, t, 0);
7612   return convert (size_type_node, t);
7613 }