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