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    There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
  29    and to process initializations in declarations (since they work
  30    like a strange sort of assignment).  */
  31
  32 #include "config.h"
  33 #include "system.h"
  34 #include "coretypes.h"
  35 #include "tm.h"
  36 #include "rtl.h"
  37 #include "tree.h"
  38 #include "langhooks.h"
  39 #include "c-tree.h"
  40 #include "tm_p.h"
  41 #include "flags.h"
  42 #include "output.h"
  43 #include "expr.h"
  44 #include "toplev.h"
  45 #include "intl.h"
  46 #include "ggc.h"
  47 #include "target.h"
  48 #include "tree-iterator.h"
  49
  50
  51 /* Nonzero if we've already printed a "missing braces around initializer"
  52    message within this initializer.  */
  53 static int missing_braces_mentioned;
  54
  55 static int require_constant_value;
  56 static int require_constant_elements;
  57
  58 static tree qualify_type (tree, tree);
  59 static int tagged_types_tu_compatible_p (tree, tree);
  60 static int comp_target_types (tree, tree, int);
  61 static int function_types_compatible_p (tree, tree);
  62 static int type_lists_compatible_p (tree, tree);
  63 static tree decl_constant_value_for_broken_optimization (tree);
  64 static tree default_function_array_conversion (tree);
  65 static tree lookup_field (tree, tree);
  66 static tree convert_arguments (tree, tree, tree, tree);
  67 static tree pointer_diff (tree, tree);
  68 static tree internal_build_compound_expr (tree, int);
  69 static tree convert_for_assignment (tree, tree, const char *, tree, tree,
  70                                     int);
  71 static void warn_for_assignment (const char *, const char *, tree, int);
  72 static tree valid_compound_expr_initializer (tree, tree);
  73 static void push_string (const char *);
  74 static void push_member_name (tree);
  75 static void push_array_bounds (int);
  76 static int spelling_length (void);
  77 static char *print_spelling (char *);
  78 static void warning_init (const char *);
  79 static tree digest_init (tree, tree, int);
  80 static void output_init_element (tree, tree, tree, int);
  81 static void output_pending_init_elements (int);
  82 static int set_designator (int);
  83 static void push_range_stack (tree);
  84 static void add_pending_init (tree, tree);
  85 static void set_nonincremental_init (void);
  86 static void set_nonincremental_init_from_string (tree);
  87 static tree find_init_member (tree);
  88 static int lvalue_or_else (tree, const char *);
  89 \f
  90 /* Do `exp = require_complete_type (exp);' to make sure exp
  91    does not have an incomplete type.  (That includes void types.)  */
  92
  93 tree
  94 require_complete_type (tree value)
  95 {
  96   tree type = TREE_TYPE (value);
  97
  98   if (value == error_mark_node || type == error_mark_node)
  99     return error_mark_node;
 100
 101   /* First, detect a valid value with a complete type.  */
 102   if (COMPLETE_TYPE_P (type))
 103     return value;
 104
 105   c_incomplete_type_error (value, type);
 106   return error_mark_node;
 107 }
 108
 109 /* Print an error message for invalid use of an incomplete type.
 110    VALUE is the expression that was used (or 0 if that isn't known)
 111    and TYPE is the type that was invalid.  */
 112
 113 void
 114 c_incomplete_type_error (tree value, tree type)
 115 {
 116   const char *type_code_string;
 117
 118   /* Avoid duplicate error message.  */
 119   if (TREE_CODE (type) == ERROR_MARK)
 120     return;
 121
 122   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 123                      || TREE_CODE (value) == PARM_DECL))
 124     error ("`%s' has an incomplete type",
 125            IDENTIFIER_POINTER (DECL_NAME (value)));
 126   else
 127     {
 128     retry:
 129       /* We must print an error message.  Be clever about what it says.  */
 130
 131       switch (TREE_CODE (type))
 132         {
 133         case RECORD_TYPE:
 134           type_code_string = "struct";
 135           break;
 136
 137         case UNION_TYPE:
 138           type_code_string = "union";
 139           break;
 140
 141         case ENUMERAL_TYPE:
 142           type_code_string = "enum";
 143           break;
 144
 145         case VOID_TYPE:
 146           error ("invalid use of void expression");
 147           return;
 148
 149         case ARRAY_TYPE:
 150           if (TYPE_DOMAIN (type))
 151             {
 152               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 153                 {
 154                   error ("invalid use of flexible array member");
 155                   return;
 156                 }
 157               type = TREE_TYPE (type);
 158               goto retry;
 159             }
 160           error ("invalid use of array with unspecified bounds");
 161           return;
 162
 163         default:
 164           abort ();
 165         }
 166
 167       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 168         error ("invalid use of undefined type `%s %s'",
 169                type_code_string, IDENTIFIER_POINTER (TYPE_NAME (type)));
 170       else
 171         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 172         error ("invalid use of incomplete typedef `%s'",
 173                IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
 174     }
 175 }
 176
 177 /* Given a type, apply default promotions wrt unnamed function
 178    arguments and return the new type.  */
 179
 180 tree
 181 c_type_promotes_to (tree type)
 182 {
 183   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 184     return double_type_node;
 185
 186   if (c_promoting_integer_type_p (type))
 187     {
 188       /* Preserve unsignedness if not really getting any wider.  */
 189       if (TYPE_UNSIGNED (type)
 190           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 191         return unsigned_type_node;
 192       return integer_type_node;
 193     }
 194
 195   return type;
 196 }
 197
 198 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 199    as well as those of TYPE.  */
 200
 201 static tree
 202 qualify_type (tree type, tree like)
 203 {
 204   return c_build_qualified_type (type,
 205                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 206 }
 207 \f
 208 /* Return the composite type of two compatible types.
 209
 210    We assume that comptypes has already been done and returned
 211    nonzero; if that isn't so, this may crash.  In particular, we
 212    assume that qualifiers match.  */
 213
 214 tree
 215 composite_type (tree t1, tree t2)
 216 {
 217   enum tree_code code1;
 218   enum tree_code code2;
 219   tree attributes;
 220
 221   /* Save time if the two types are the same.  */
 222
 223   if (t1 == t2) return t1;
 224
 225   /* If one type is nonsense, use the other.  */
 226   if (t1 == error_mark_node)
 227     return t2;
 228   if (t2 == error_mark_node)
 229     return t1;
 230
 231   code1 = TREE_CODE (t1);
 232   code2 = TREE_CODE (t2);
 233
 234   /* Merge the attributes.  */
 235   attributes = targetm.merge_type_attributes (t1, t2);
 236
 237   /* If one is an enumerated type and the other is the compatible
 238      integer type, the composite type might be either of the two
 239      (DR#013 question 3).  For consistency, use the enumerated type as
 240      the composite type.  */
 241
 242   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 243     return t1;
 244   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 245     return t2;
 246
 247   if (code1 != code2)
 248     abort ();
 249
 250   switch (code1)
 251     {
 252     case POINTER_TYPE:
 253       /* For two pointers, do this recursively on the target type.  */
 254       {
 255         tree pointed_to_1 = TREE_TYPE (t1);
 256         tree pointed_to_2 = TREE_TYPE (t2);
 257         tree target = composite_type (pointed_to_1, pointed_to_2);
 258         t1 = build_pointer_type (target);
 259         return build_type_attribute_variant (t1, attributes);
 260       }
 261
 262     case ARRAY_TYPE:
 263       {
 264         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 265         /* Save space: see if the result is identical to one of the args.  */
 266         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
 267           return build_type_attribute_variant (t1, attributes);
 268         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
 269           return build_type_attribute_variant (t2, attributes);
 270         /* Merge the element types, and have a size if either arg has one.  */
 271         t1 = build_array_type (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
 272         return build_type_attribute_variant (t1, attributes);
 273       }
 274
 275     case FUNCTION_TYPE:
 276       /* Function types: prefer the one that specified arg types.
 277          If both do, merge the arg types.  Also merge the return types.  */
 278       {
 279         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 280         tree p1 = TYPE_ARG_TYPES (t1);
 281         tree p2 = TYPE_ARG_TYPES (t2);
 282         int len;
 283         tree newargs, n;
 284         int i;
 285
 286         /* Save space: see if the result is identical to one of the args.  */
 287         if (valtype == TREE_TYPE (t1) && ! TYPE_ARG_TYPES (t2))
 288           return build_type_attribute_variant (t1, attributes);
 289         if (valtype == TREE_TYPE (t2) && ! TYPE_ARG_TYPES (t1))
 290           return build_type_attribute_variant (t2, attributes);
 291
 292         /* Simple way if one arg fails to specify argument types.  */
 293         if (TYPE_ARG_TYPES (t1) == 0)
 294          {
 295            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 296            return build_type_attribute_variant (t1, attributes);
 297          }
 298         if (TYPE_ARG_TYPES (t2) == 0)
 299          {
 300            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 301            return build_type_attribute_variant (t1, attributes);
 302          }
 303
 304         /* If both args specify argument types, we must merge the two
 305            lists, argument by argument.  */
 306         /* Tell global_bindings_p to return false so that variable_size
 307            doesn't abort on VLAs in parameter types.  */
 308         c_override_global_bindings_to_false = true;
 309
 310         len = list_length (p1);
 311         newargs = 0;
 312
 313         for (i = 0; i < len; i++)
 314           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 315
 316         n = newargs;
 317
 318         for (; p1;
 319              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 320           {
 321             /* A null type means arg type is not specified.
 322                Take whatever the other function type has.  */
 323             if (TREE_VALUE (p1) == 0)
 324               {
 325                 TREE_VALUE (n) = TREE_VALUE (p2);
 326                 goto parm_done;
 327               }
 328             if (TREE_VALUE (p2) == 0)
 329               {
 330                 TREE_VALUE (n) = TREE_VALUE (p1);
 331                 goto parm_done;
 332               }
 333
 334             /* Given  wait (union {union wait *u; int *i} *)
 335                and  wait (union wait *),
 336                prefer  union wait *  as type of parm.  */
 337             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 338                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 339               {
 340                 tree memb;
 341                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 342                      memb; memb = TREE_CHAIN (memb))
 343                   if (comptypes (TREE_TYPE (memb), TREE_VALUE (p2)))
 344                     {
 345                       TREE_VALUE (n) = TREE_VALUE (p2);
 346                       if (pedantic)
 347                         pedwarn ("function types not truly compatible in ISO C");
 348                       goto parm_done;
 349                     }
 350               }
 351             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 352                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 353               {
 354                 tree memb;
 355                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 356                      memb; memb = TREE_CHAIN (memb))
 357                   if (comptypes (TREE_TYPE (memb), TREE_VALUE (p1)))
 358                     {
 359                       TREE_VALUE (n) = TREE_VALUE (p1);
 360                       if (pedantic)
 361                         pedwarn ("function types not truly compatible in ISO C");
 362                       goto parm_done;
 363                     }
 364               }
 365             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 366           parm_done: ;
 367           }
 368
 369         c_override_global_bindings_to_false = false;
 370         t1 = build_function_type (valtype, newargs);
 371         /* ... falls through ...  */
 372       }
 373
 374     default:
 375       return build_type_attribute_variant (t1, attributes);
 376     }
 377
 378 }
 379
 380 /* Return the type of a conditional expression between pointers to
 381    possibly differently qualified versions of compatible types.
 382
 383    We assume that comp_target_types has already been done and returned
 384    nonzero; if that isn't so, this may crash.  */
 385
 386 static tree
 387 common_pointer_type (tree t1, tree t2)
 388 {
 389   tree attributes;
 390   tree pointed_to_1;
 391   tree pointed_to_2;
 392   tree target;
 393
 394   /* Save time if the two types are the same.  */
 395
 396   if (t1 == t2) return t1;
 397
 398   /* If one type is nonsense, use the other.  */
 399   if (t1 == error_mark_node)
 400     return t2;
 401   if (t2 == error_mark_node)
 402     return t1;
 403
 404   if (TREE_CODE (t1) != POINTER_TYPE || TREE_CODE (t2) != POINTER_TYPE)
 405     abort ();
 406
 407   /* Merge the attributes.  */
 408   attributes = targetm.merge_type_attributes (t1, t2);
 409
 410   /* Find the composite type of the target types, and combine the
 411      qualifiers of the two types' targets.  */
 412   pointed_to_1 = TREE_TYPE (t1);
 413   pointed_to_2 = TREE_TYPE (t2);
 414   target = composite_type (TYPE_MAIN_VARIANT (pointed_to_1),
 415                            TYPE_MAIN_VARIANT (pointed_to_2));
 416   t1 = build_pointer_type (c_build_qualified_type
 417                            (target,
 418                             TYPE_QUALS (pointed_to_1) |
 419                             TYPE_QUALS (pointed_to_2)));
 420   return build_type_attribute_variant (t1, attributes);
 421 }
 422
 423 /* Return the common type for two arithmetic types under the usual
 424    arithmetic conversions.  The default conversions have already been
 425    applied, and enumerated types converted to their compatible integer
 426    types.  The resulting type is unqualified and has no attributes.
 427
 428    This is the type for the result of most arithmetic operations
 429    if the operands have the given two types.  */
 430
 431 tree
 432 common_type (tree t1, tree t2)
 433 {
 434   enum tree_code code1;
 435   enum tree_code code2;
 436
 437   /* If one type is nonsense, use the other.  */
 438   if (t1 == error_mark_node)
 439     return t2;
 440   if (t2 == error_mark_node)
 441     return t1;
 442
 443   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 444     t1 = TYPE_MAIN_VARIANT (t1);
 445
 446   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 447     t2 = TYPE_MAIN_VARIANT (t2);
 448
 449   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 450     t1 = build_type_attribute_variant (t1, NULL_TREE);
 451
 452   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 453     t2 = build_type_attribute_variant (t2, NULL_TREE);
 454
 455   /* Save time if the two types are the same.  */
 456
 457   if (t1 == t2) return t1;
 458
 459   code1 = TREE_CODE (t1);
 460   code2 = TREE_CODE (t2);
 461
 462   if (code1 != VECTOR_TYPE && code1 != COMPLEX_TYPE
 463       && code1 != REAL_TYPE && code1 != INTEGER_TYPE)
 464     abort ();
 465
 466   if (code2 != VECTOR_TYPE && code2 != COMPLEX_TYPE
 467       && code2 != REAL_TYPE && code2 != INTEGER_TYPE)
 468     abort ();
 469
 470   /* If one type is a vector type, return that type.  (How the usual
 471      arithmetic conversions apply to the vector types extension is not
 472      precisely specified.)  */
 473   if (code1 == VECTOR_TYPE)
 474     return t1;
 475
 476   if (code2 == VECTOR_TYPE)
 477     return t2;
 478
 479   /* If one type is complex, form the common type of the non-complex
 480      components, then make that complex.  Use T1 or T2 if it is the
 481      required type.  */
 482   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 483     {
 484       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 485       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 486       tree subtype = common_type (subtype1, subtype2);
 487
 488       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 489         return t1;
 490       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 491         return t2;
 492       else
 493         return build_complex_type (subtype);
 494     }
 495
 496   /* If only one is real, use it as the result.  */
 497
 498   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 499     return t1;
 500
 501   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 502     return t2;
 503
 504   /* Both real or both integers; use the one with greater precision.  */
 505
 506   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 507     return t1;
 508   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 509     return t2;
 510
 511   /* Same precision.  Prefer long longs to longs to ints when the
 512      same precision, following the C99 rules on integer type rank
 513      (which are equivalent to the C90 rules for C90 types).  */
 514
 515   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 516       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 517     return long_long_unsigned_type_node;
 518
 519   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 520       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 521     {
 522       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 523         return long_long_unsigned_type_node;
 524       else
 525         return long_long_integer_type_node;
 526     }
 527
 528   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 529       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 530     return long_unsigned_type_node;
 531
 532   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 533       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 534     {
 535       /* But preserve unsignedness from the other type,
 536          since long cannot hold all the values of an unsigned int.  */
 537       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 538         return long_unsigned_type_node;
 539       else
 540         return long_integer_type_node;
 541     }
 542
 543   /* Likewise, prefer long double to double even if same size.  */
 544   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 545       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 546     return long_double_type_node;
 547
 548   /* Otherwise prefer the unsigned one.  */
 549
 550   if (TYPE_UNSIGNED (t1))
 551     return t1;
 552   else
 553     return t2;
 554 }
 555 \f
 556 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 557    or various other operations.  Return 2 if they are compatible
 558    but a warning may be needed if you use them together.  */
 559
 560 int
 561 comptypes (tree type1, tree type2)
 562 {
 563   tree t1 = type1;
 564   tree t2 = type2;
 565   int attrval, val;
 566
 567   /* Suppress errors caused by previously reported errors.  */
 568
 569   if (t1 == t2 || !t1 || !t2
 570       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 571     return 1;
 572
 573   /* If either type is the internal version of sizetype, return the
 574      language version.  */
 575   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 576       && TYPE_ORIG_SIZE_TYPE (t1))
 577     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 578
 579   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 580       && TYPE_ORIG_SIZE_TYPE (t2))
 581     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 582
 583
 584   /* Enumerated types are compatible with integer types, but this is
 585      not transitive: two enumerated types in the same translation unit
 586      are compatible with each other only if they are the same type.  */
 587
 588   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 589     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 590   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 591     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 592
 593   if (t1 == t2)
 594     return 1;
 595
 596   /* Different classes of types can't be compatible.  */
 597
 598   if (TREE_CODE (t1) != TREE_CODE (t2))
 599     return 0;
 600
 601   /* Qualifiers must match. C99 6.7.3p9 */
 602
 603   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 604     return 0;
 605
 606   /* Allow for two different type nodes which have essentially the same
 607      definition.  Note that we already checked for equality of the type
 608      qualifiers (just above).  */
 609
 610   if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 611     return 1;
 612
 613   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 614   if (! (attrval = targetm.comp_type_attributes (t1, t2)))
 615      return 0;
 616
 617   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 618   val = 0;
 619
 620   switch (TREE_CODE (t1))
 621     {
 622     case POINTER_TYPE:
 623       /* We must give ObjC the first crack at comparing pointers, since
 624            protocol qualifiers may be involved.  */
 625       if (c_dialect_objc () && (val = objc_comptypes (t1, t2, 0)) >= 0)
 626         break;
 627       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 628              ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
 629       break;
 630
 631     case FUNCTION_TYPE:
 632       val = function_types_compatible_p (t1, t2);
 633       break;
 634
 635     case ARRAY_TYPE:
 636       {
 637         tree d1 = TYPE_DOMAIN (t1);
 638         tree d2 = TYPE_DOMAIN (t2);
 639         bool d1_variable, d2_variable;
 640         bool d1_zero, d2_zero;
 641         val = 1;
 642
 643         /* Target types must match incl. qualifiers.  */
 644         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 645             && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
 646           return 0;
 647
 648         /* Sizes must match unless one is missing or variable.  */
 649         if (d1 == 0 || d2 == 0 || d1 == d2)
 650           break;
 651
 652         d1_zero = ! TYPE_MAX_VALUE (d1);
 653         d2_zero = ! TYPE_MAX_VALUE (d2);
 654
 655         d1_variable = (! d1_zero
 656                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 657                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 658         d2_variable = (! d2_zero
 659                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 660                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 661
 662         if (d1_variable || d2_variable)
 663           break;
 664         if (d1_zero && d2_zero)
 665           break;
 666         if (d1_zero || d2_zero
 667             || ! tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 668             || ! tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 669           val = 0;
 670
 671         break;
 672       }
 673
 674     case RECORD_TYPE:
 675       /* We are dealing with two distinct structs.  In assorted Objective-C
 676          corner cases, however, these can still be deemed equivalent.  */
 677       if (c_dialect_objc () && objc_comptypes (t1, t2, 0) == 1)
 678         val = 1;
 679
 680     case ENUMERAL_TYPE:
 681     case UNION_TYPE:
 682       if (val != 1 && !same_translation_unit_p (t1, t2))
 683         val = tagged_types_tu_compatible_p (t1, t2);
 684       break;
 685
 686     case VECTOR_TYPE:
 687       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 688             && comptypes (TREE_TYPE (t1), TREE_TYPE (t2));
 689       break;
 690
 691     default:
 692       break;
 693     }
 694   return attrval == 2 && val == 1 ? 2 : val;
 695 }
 696
 697 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 698    ignoring their qualifiers.  REFLEXIVE is only used by ObjC - set it
 699    to 1 or 0 depending if the check of the pointer types is meant to
 700    be reflexive or not (typically, assignments are not reflexive,
 701    while comparisons are reflexive).
 702 */
 703
 704 static int
 705 comp_target_types (tree ttl, tree ttr, int reflexive)
 706 {
 707   int val;
 708
 709   /* Give objc_comptypes a crack at letting these types through.  */
 710   if ((val = objc_comptypes (ttl, ttr, reflexive)) >= 0)
 711     return val;
 712
 713   val = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (ttl)),
 714                    TYPE_MAIN_VARIANT (TREE_TYPE (ttr)));
 715
 716   if (val == 2 && pedantic)
 717     pedwarn ("types are not quite compatible");
 718   return val;
 719 }
 720 \f
 721 /* Subroutines of `comptypes'.  */
 722
 723 /* Determine whether two trees derive from the same translation unit.
 724    If the CONTEXT chain ends in a null, that tree's context is still
 725    being parsed, so if two trees have context chains ending in null,
 726    they're in the same translation unit.  */
 727 int
 728 same_translation_unit_p (tree t1, tree t2)
 729 {
 730   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 731     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 732       {
 733       case 'd': t1 = DECL_CONTEXT (t1); break;
 734       case 't': t1 = TYPE_CONTEXT (t1); break;
 735       case 'x': t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 736       default: abort ();
 737       }
 738
 739   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 740     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 741       {
 742       case 'd': t2 = DECL_CONTEXT (t2); break;
 743       case 't': t2 = TYPE_CONTEXT (t2); break;
 744       case 'x': t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 745       default: abort ();
 746       }
 747
 748   return t1 == t2;
 749 }
 750
 751 /* The C standard says that two structures in different translation
 752    units are compatible with each other only if the types of their
 753    fields are compatible (among other things).  So, consider two copies
 754    of this structure:  */
 755
 756 struct tagged_tu_seen {
 757   const struct tagged_tu_seen * next;
 758   tree t1;
 759   tree t2;
 760 };
 761
 762 /* Can they be compatible with each other?  We choose to break the
 763    recursion by allowing those types to be compatible.  */
 764
 765 static const struct tagged_tu_seen * tagged_tu_seen_base;
 766
 767 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 768    compatible.  If the two types are not the same (which has been
 769    checked earlier), this can only happen when multiple translation
 770    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 771    rules.  */
 772
 773 static int
 774 tagged_types_tu_compatible_p (tree t1, tree t2)
 775 {
 776   tree s1, s2;
 777   bool needs_warning = false;
 778
 779   /* We have to verify that the tags of the types are the same.  This
 780      is harder than it looks because this may be a typedef, so we have
 781      to go look at the original type.  It may even be a typedef of a
 782      typedef...
 783      In the case of compiler-created builtin structs the TYPE_DECL
 784      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 785   while (TYPE_NAME (t1)
 786          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 787          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 788     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 789
 790   while (TYPE_NAME (t2)
 791          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 792          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 793     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 794
 795   /* C90 didn't have the requirement that the two tags be the same.  */
 796   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 797     return 0;
 798
 799   /* C90 didn't say what happened if one or both of the types were
 800      incomplete; we choose to follow C99 rules here, which is that they
 801      are compatible.  */
 802   if (TYPE_SIZE (t1) == NULL
 803       || TYPE_SIZE (t2) == NULL)
 804     return 1;
 805
 806   {
 807     const struct tagged_tu_seen * tts_i;
 808     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 809       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 810         return 1;
 811   }
 812
 813   switch (TREE_CODE (t1))
 814     {
 815     case ENUMERAL_TYPE:
 816       {
 817
 818         /* Speed up the case where the type values are in the same order.  */
 819         tree tv1 = TYPE_VALUES (t1);
 820         tree tv2 = TYPE_VALUES (t2);
 821
 822         if (tv1 == tv2)
 823           return 1;
 824
 825         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
 826           {
 827             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
 828               break;
 829             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
 830               return 0;
 831           }
 832
 833         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
 834           return 1;
 835         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
 836           return 0;
 837
 838         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
 839           return 0;
 840
 841         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
 842           {
 843             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
 844             if (s2 == NULL
 845                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
 846               return 0;
 847           }
 848         return 1;
 849       }
 850
 851     case UNION_TYPE:
 852       {
 853         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
 854           return 0;
 855
 856         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
 857           {
 858             bool ok = false;
 859             struct tagged_tu_seen tts;
 860
 861             tts.next = tagged_tu_seen_base;
 862             tts.t1 = t1;
 863             tts.t2 = t2;
 864             tagged_tu_seen_base = &tts;
 865
 866             if (DECL_NAME (s1) != NULL)
 867               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
 868                 if (DECL_NAME (s1) == DECL_NAME (s2))
 869                   {
 870                     int result;
 871                     result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 872                     if (result == 0)
 873                       break;
 874                     if (result == 2)
 875                       needs_warning = true;
 876
 877                     if (TREE_CODE (s1) == FIELD_DECL
 878                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 879                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
 880                       break;
 881
 882                     ok = true;
 883                     break;
 884                   }
 885             tagged_tu_seen_base = tts.next;
 886             if (! ok)
 887               return 0;
 888           }
 889         return needs_warning ? 2 : 1;
 890       }
 891
 892     case RECORD_TYPE:
 893       {
 894         struct tagged_tu_seen tts;
 895
 896         tts.next = tagged_tu_seen_base;
 897         tts.t1 = t1;
 898         tts.t2 = t2;
 899         tagged_tu_seen_base = &tts;
 900
 901         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
 902              s1 && s2;
 903              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
 904           {
 905             int result;
 906             if (TREE_CODE (s1) != TREE_CODE (s2)
 907                 || DECL_NAME (s1) != DECL_NAME (s2))
 908               break;
 909             result = comptypes (TREE_TYPE (s1), TREE_TYPE (s2));
 910             if (result == 0)
 911               break;
 912             if (result == 2)
 913               needs_warning = true;
 914
 915             if (TREE_CODE (s1) == FIELD_DECL
 916                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
 917                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
 918               break;
 919           }
 920         tagged_tu_seen_base = tts.next;
 921         if (s1 && s2)
 922           return 0;
 923         return needs_warning ? 2 : 1;
 924       }
 925
 926     default:
 927       abort ();
 928     }
 929 }
 930
 931 /* Return 1 if two function types F1 and F2 are compatible.
 932    If either type specifies no argument types,
 933    the other must specify a fixed number of self-promoting arg types.
 934    Otherwise, if one type specifies only the number of arguments,
 935    the other must specify that number of self-promoting arg types.
 936    Otherwise, the argument types must match.  */
 937
 938 static int
 939 function_types_compatible_p (tree f1, tree f2)
 940 {
 941   tree args1, args2;
 942   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 943   int val = 1;
 944   int val1;
 945   tree ret1, ret2;
 946
 947   ret1 = TREE_TYPE (f1);
 948   ret2 = TREE_TYPE (f2);
 949
 950   /* 'volatile' qualifiers on a function's return type mean the function
 951      is noreturn.  */
 952   if (pedantic && TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
 953     pedwarn ("function return types not compatible due to `volatile'");
 954   if (TYPE_VOLATILE (ret1))
 955     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
 956                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
 957   if (TYPE_VOLATILE (ret2))
 958     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
 959                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
 960   val = comptypes (ret1, ret2);
 961   if (val == 0)
 962     return 0;
 963
 964   args1 = TYPE_ARG_TYPES (f1);
 965   args2 = TYPE_ARG_TYPES (f2);
 966
 967   /* An unspecified parmlist matches any specified parmlist
 968      whose argument types don't need default promotions.  */
 969
 970   if (args1 == 0)
 971     {
 972       if (!self_promoting_args_p (args2))
 973         return 0;
 974       /* If one of these types comes from a non-prototype fn definition,
 975          compare that with the other type's arglist.
 976          If they don't match, ask for a warning (but no error).  */
 977       if (TYPE_ACTUAL_ARG_TYPES (f1)
 978           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
 979         val = 2;
 980       return val;
 981     }
 982   if (args2 == 0)
 983     {
 984       if (!self_promoting_args_p (args1))
 985         return 0;
 986       if (TYPE_ACTUAL_ARG_TYPES (f2)
 987           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
 988         val = 2;
 989       return val;
 990     }
 991
 992   /* Both types have argument lists: compare them and propagate results.  */
 993   val1 = type_lists_compatible_p (args1, args2);
 994   return val1 != 1 ? val1 : val;
 995 }
 996
 997 /* Check two lists of types for compatibility,
 998    returning 0 for incompatible, 1 for compatible,
 999    or 2 for compatible with warning.  */
1000
1001 static int
1002 type_lists_compatible_p (tree args1, tree args2)
1003 {
1004   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1005   int val = 1;
1006   int newval = 0;
1007
1008   while (1)
1009     {
1010       if (args1 == 0 && args2 == 0)
1011         return val;
1012       /* If one list is shorter than the other,
1013          they fail to match.  */
1014       if (args1 == 0 || args2 == 0)
1015         return 0;
1016       /* A null pointer instead of a type
1017          means there is supposed to be an argument
1018          but nothing is specified about what type it has.
1019          So match anything that self-promotes.  */
1020       if (TREE_VALUE (args1) == 0)
1021         {
1022           if (c_type_promotes_to (TREE_VALUE (args2)) != TREE_VALUE (args2))
1023             return 0;
1024         }
1025       else if (TREE_VALUE (args2) == 0)
1026         {
1027           if (c_type_promotes_to (TREE_VALUE (args1)) != TREE_VALUE (args1))
1028             return 0;
1029         }
1030       /* If one of the lists has an error marker, ignore this arg.  */
1031       else if (TREE_CODE (TREE_VALUE (args1)) == ERROR_MARK
1032                || TREE_CODE (TREE_VALUE (args2)) == ERROR_MARK)
1033         ;
1034       else if (! (newval = comptypes (TYPE_MAIN_VARIANT (TREE_VALUE (args1)),
1035                                       TYPE_MAIN_VARIANT (TREE_VALUE (args2)))))
1036         {
1037           /* Allow  wait (union {union wait *u; int *i} *)
1038              and  wait (union wait *)  to be compatible.  */
1039           if (TREE_CODE (TREE_VALUE (args1)) == UNION_TYPE
1040               && (TYPE_NAME (TREE_VALUE (args1)) == 0
1041                   || TYPE_TRANSPARENT_UNION (TREE_VALUE (args1)))
1042               && TREE_CODE (TYPE_SIZE (TREE_VALUE (args1))) == INTEGER_CST
1043               && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args1)),
1044                                      TYPE_SIZE (TREE_VALUE (args2))))
1045             {
1046               tree memb;
1047               for (memb = TYPE_FIELDS (TREE_VALUE (args1));
1048                    memb; memb = TREE_CHAIN (memb))
1049                 if (comptypes (TREE_TYPE (memb), TREE_VALUE (args2)))
1050                   break;
1051               if (memb == 0)
1052                 return 0;
1053             }
1054           else if (TREE_CODE (TREE_VALUE (args2)) == UNION_TYPE
1055                    && (TYPE_NAME (TREE_VALUE (args2)) == 0
1056                        || TYPE_TRANSPARENT_UNION (TREE_VALUE (args2)))
1057                    && TREE_CODE (TYPE_SIZE (TREE_VALUE (args2))) == INTEGER_CST
1058                    && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args2)),
1059                                           TYPE_SIZE (TREE_VALUE (args1))))
1060             {
1061               tree memb;
1062               for (memb = TYPE_FIELDS (TREE_VALUE (args2));
1063                    memb; memb = TREE_CHAIN (memb))
1064                 if (comptypes (TREE_TYPE (memb), TREE_VALUE (args1)))
1065                   break;
1066               if (memb == 0)
1067                 return 0;
1068             }
1069           else
1070             return 0;
1071         }
1072
1073       /* comptypes said ok, but record if it said to warn.  */
1074       if (newval > val)
1075         val = newval;
1076
1077       args1 = TREE_CHAIN (args1);
1078       args2 = TREE_CHAIN (args2);
1079     }
1080 }
1081 \f
1082 /* Compute the size to increment a pointer by.  */
1083
1084 tree
1085 c_size_in_bytes (tree type)
1086 {
1087   enum tree_code code = TREE_CODE (type);
1088
1089   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1090     return size_one_node;
1091
1092   if (!COMPLETE_OR_VOID_TYPE_P (type))
1093     {
1094       error ("arithmetic on pointer to an incomplete type");
1095       return size_one_node;
1096     }
1097
1098   /* Convert in case a char is more than one unit.  */
1099   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1100                      size_int (TYPE_PRECISION (char_type_node)
1101                                / BITS_PER_UNIT));
1102 }
1103 \f
1104 /* Return either DECL or its known constant value (if it has one).  */
1105
1106 tree
1107 decl_constant_value (tree decl)
1108 {
1109   if (/* Don't change a variable array bound or initial value to a constant
1110          in a place where a variable is invalid.  Note that DECL_INITIAL
1111          isn't valid for a PARM_DECL.  */
1112       current_function_decl != 0
1113       && TREE_CODE (decl) != PARM_DECL
1114       && ! TREE_THIS_VOLATILE (decl)
1115       && TREE_READONLY (decl)
1116       && DECL_INITIAL (decl) != 0
1117       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1118       /* This is invalid if initial value is not constant.
1119          If it has either a function call, a memory reference,
1120          or a variable, then re-evaluating it could give different results.  */
1121       && TREE_CONSTANT (DECL_INITIAL (decl))
1122       /* Check for cases where this is sub-optimal, even though valid.  */
1123       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1124     return DECL_INITIAL (decl);
1125   return decl;
1126 }
1127
1128 /* Return either DECL or its known constant value (if it has one), but
1129    return DECL if pedantic or DECL has mode BLKmode.  This is for
1130    bug-compatibility with the old behavior of decl_constant_value
1131    (before GCC 3.0); every use of this function is a bug and it should
1132    be removed before GCC 3.1.  It is not appropriate to use pedantic
1133    in a way that affects optimization, and BLKmode is probably not the
1134    right test for avoiding misoptimizations either.  */
1135
1136 static tree
1137 decl_constant_value_for_broken_optimization (tree decl)
1138 {
1139   if (pedantic || DECL_MODE (decl) == BLKmode)
1140     return decl;
1141   else
1142     return decl_constant_value (decl);
1143 }
1144
1145
1146 /* Perform the default conversion of arrays and functions to pointers.
1147    Return the result of converting EXP.  For any other expression, just
1148    return EXP.  */
1149
1150 static tree
1151 default_function_array_conversion (tree exp)
1152 {
1153   tree orig_exp;
1154   tree type = TREE_TYPE (exp);
1155   enum tree_code code = TREE_CODE (type);
1156   int not_lvalue = 0;
1157
1158   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1159      an lvalue.
1160
1161      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1162      to integer and cause infinite recursion.  */
1163   orig_exp = exp;
1164   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1165          || (TREE_CODE (exp) == NOP_EXPR
1166              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1167     {
1168       if (TREE_CODE (exp) == NON_LVALUE_EXPR)
1169         not_lvalue = 1;
1170       exp = TREE_OPERAND (exp, 0);
1171     }
1172
1173   /* Preserve the original expression code.  */
1174   if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (exp))))
1175     C_SET_EXP_ORIGINAL_CODE (exp, C_EXP_ORIGINAL_CODE (orig_exp));
1176
1177   if (code == FUNCTION_TYPE)
1178     {
1179       return build_unary_op (ADDR_EXPR, exp, 0);
1180     }
1181   if (code == ARRAY_TYPE)
1182     {
1183       tree adr;
1184       tree restype = TREE_TYPE (type);
1185       tree ptrtype;
1186       int constp = 0;
1187       int volatilep = 0;
1188       int lvalue_array_p;
1189
1190       if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'r' || DECL_P (exp))
1191         {
1192           constp = TREE_READONLY (exp);
1193           volatilep = TREE_THIS_VOLATILE (exp);
1194         }
1195
1196       if (TYPE_QUALS (type) || constp || volatilep)
1197         restype
1198           = c_build_qualified_type (restype,
1199                                     TYPE_QUALS (type)
1200                                     | (constp * TYPE_QUAL_CONST)
1201                                     | (volatilep * TYPE_QUAL_VOLATILE));
1202
1203       if (TREE_CODE (exp) == INDIRECT_REF)
1204         return convert (build_pointer_type (restype),
1205                         TREE_OPERAND (exp, 0));
1206
1207       if (TREE_CODE (exp) == COMPOUND_EXPR)
1208         {
1209           tree op1 = default_conversion (TREE_OPERAND (exp, 1));
1210           return build (COMPOUND_EXPR, TREE_TYPE (op1),
1211                         TREE_OPERAND (exp, 0), op1);
1212         }
1213
1214       lvalue_array_p = !not_lvalue && lvalue_p (exp);
1215       if (!flag_isoc99 && !lvalue_array_p)
1216         {
1217           /* Before C99, non-lvalue arrays do not decay to pointers.
1218              Normally, using such an array would be invalid; but it can
1219              be used correctly inside sizeof or as a statement expression.
1220              Thus, do not give an error here; an error will result later.  */
1221           return exp;
1222         }
1223
1224       ptrtype = build_pointer_type (restype);
1225
1226       if (TREE_CODE (exp) == VAR_DECL)
1227         {
1228           /* ??? This is not really quite correct
1229              in that the type of the operand of ADDR_EXPR
1230              is not the target type of the type of the ADDR_EXPR itself.
1231              Question is, can this lossage be avoided?  */
1232           adr = build1 (ADDR_EXPR, ptrtype, exp);
1233           if (!c_mark_addressable (exp))
1234             return error_mark_node;
1235           TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1236           return adr;
1237         }
1238       /* This way is better for a COMPONENT_REF since it can
1239          simplify the offset for a component.  */
1240       adr = build_unary_op (ADDR_EXPR, exp, 1);
1241       return convert (ptrtype, adr);
1242     }
1243   return exp;
1244 }
1245
1246 /* Perform default promotions for C data used in expressions.
1247    Arrays and functions are converted to pointers;
1248    enumeral types or short or char, to int.
1249    In addition, manifest constants symbols are replaced by their values.  */
1250
1251 tree
1252 default_conversion (tree exp)
1253 {
1254   tree orig_exp;
1255   tree type = TREE_TYPE (exp);
1256   enum tree_code code = TREE_CODE (type);
1257
1258   if (code == FUNCTION_TYPE || code == ARRAY_TYPE)
1259     return default_function_array_conversion (exp);
1260
1261   /* Constants can be used directly unless they're not loadable.  */
1262   if (TREE_CODE (exp) == CONST_DECL)
1263     exp = DECL_INITIAL (exp);
1264
1265   /* Replace a nonvolatile const static variable with its value unless
1266      it is an array, in which case we must be sure that taking the
1267      address of the array produces consistent results.  */
1268   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1269     {
1270       exp = decl_constant_value_for_broken_optimization (exp);
1271       type = TREE_TYPE (exp);
1272     }
1273
1274   /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1275      an lvalue.
1276
1277      Do not use STRIP_NOPS here!  It will remove conversions from pointer
1278      to integer and cause infinite recursion.  */
1279   orig_exp = exp;
1280   while (TREE_CODE (exp) == NON_LVALUE_EXPR
1281          || (TREE_CODE (exp) == NOP_EXPR
1282              && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
1283     exp = TREE_OPERAND (exp, 0);
1284
1285   /* Preserve the original expression code.  */
1286   if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (exp))))
1287     C_SET_EXP_ORIGINAL_CODE (exp, C_EXP_ORIGINAL_CODE (orig_exp));
1288
1289   /* Normally convert enums to int,
1290      but convert wide enums to something wider.  */
1291   if (code == ENUMERAL_TYPE)
1292     {
1293       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1294                                           TYPE_PRECISION (integer_type_node)),
1295                                      ((TYPE_PRECISION (type)
1296                                        >= TYPE_PRECISION (integer_type_node))
1297                                       && TYPE_UNSIGNED (type)));
1298
1299       return convert (type, exp);
1300     }
1301
1302   if (TREE_CODE (exp) == COMPONENT_REF
1303       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1304       /* If it's thinner than an int, promote it like a
1305          c_promoting_integer_type_p, otherwise leave it alone.  */
1306       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1307                                TYPE_PRECISION (integer_type_node)))
1308     return convert (integer_type_node, exp);
1309
1310   if (c_promoting_integer_type_p (type))
1311     {
1312       /* Preserve unsignedness if not really getting any wider.  */
1313       if (TYPE_UNSIGNED (type)
1314           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1315         return convert (unsigned_type_node, exp);
1316
1317       return convert (integer_type_node, exp);
1318     }
1319
1320   if (code == VOID_TYPE)
1321     {
1322       error ("void value not ignored as it ought to be");
1323       return error_mark_node;
1324     }
1325   return exp;
1326 }
1327 \f
1328 /* Look up COMPONENT in a structure or union DECL.
1329
1330    If the component name is not found, returns NULL_TREE.  Otherwise,
1331    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1332    stepping down the chain to the component, which is in the last
1333    TREE_VALUE of the list.  Normally the list is of length one, but if
1334    the component is embedded within (nested) anonymous structures or
1335    unions, the list steps down the chain to the component.  */
1336
1337 static tree
1338 lookup_field (tree decl, tree component)
1339 {
1340   tree type = TREE_TYPE (decl);
1341   tree field;
1342
1343   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1344      to the field elements.  Use a binary search on this array to quickly
1345      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1346      will always be set for structures which have many elements.  */
1347
1348   if (TYPE_LANG_SPECIFIC (type))
1349     {
1350       int bot, top, half;
1351       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1352
1353       field = TYPE_FIELDS (type);
1354       bot = 0;
1355       top = TYPE_LANG_SPECIFIC (type)->s->len;
1356       while (top - bot > 1)
1357         {
1358           half = (top - bot + 1) >> 1;
1359           field = field_array[bot+half];
1360
1361           if (DECL_NAME (field) == NULL_TREE)
1362             {
1363               /* Step through all anon unions in linear fashion.  */
1364               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1365                 {
1366                   field = field_array[bot++];
1367                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1368                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1369                     {
1370                       tree anon = lookup_field (field, component);
1371
1372                       if (anon)
1373                         return tree_cons (NULL_TREE, field, anon);
1374                     }
1375                 }
1376
1377               /* Entire record is only anon unions.  */
1378               if (bot > top)
1379                 return NULL_TREE;
1380
1381               /* Restart the binary search, with new lower bound.  */
1382               continue;
1383             }
1384
1385           if (DECL_NAME (field) == component)
1386             break;
1387           if (DECL_NAME (field) < component)
1388             bot += half;
1389           else
1390             top = bot + half;
1391         }
1392
1393       if (DECL_NAME (field_array[bot]) == component)
1394         field = field_array[bot];
1395       else if (DECL_NAME (field) != component)
1396         return NULL_TREE;
1397     }
1398   else
1399     {
1400       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1401         {
1402           if (DECL_NAME (field) == NULL_TREE
1403               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1404                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1405             {
1406               tree anon = lookup_field (field, component);
1407
1408               if (anon)
1409                 return tree_cons (NULL_TREE, field, anon);
1410             }
1411
1412           if (DECL_NAME (field) == component)
1413             break;
1414         }
1415
1416       if (field == NULL_TREE)
1417         return NULL_TREE;
1418     }
1419
1420   return tree_cons (NULL_TREE, field, NULL_TREE);
1421 }
1422
1423 /* Make an expression to refer to the COMPONENT field of
1424    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1425
1426 tree
1427 build_component_ref (tree datum, tree component)
1428 {
1429   tree type = TREE_TYPE (datum);
1430   enum tree_code code = TREE_CODE (type);
1431   tree field = NULL;
1432   tree ref;
1433
1434   if (!objc_is_public (datum, component))
1435     return error_mark_node;
1436
1437   /* If DATUM is a COMPOUND_EXPR, move our reference inside it.
1438      Ensure that the arguments are not lvalues; otherwise,
1439      if the component is an array, it would wrongly decay to a pointer in
1440      C89 mode.
1441      We cannot do this with a COND_EXPR, because in a conditional expression
1442      the default promotions are applied to both sides, and this would yield
1443      the wrong type of the result; for example, if the components have
1444      type "char".  */
1445   switch (TREE_CODE (datum))
1446     {
1447     case COMPOUND_EXPR:
1448       {
1449         tree value = build_component_ref (TREE_OPERAND (datum, 1), component);
1450         return build (COMPOUND_EXPR, TREE_TYPE (value),
1451                       TREE_OPERAND (datum, 0), non_lvalue (value));
1452       }
1453     default:
1454       break;
1455     }
1456
1457   /* See if there is a field or component with name COMPONENT.  */
1458
1459   if (code == RECORD_TYPE || code == UNION_TYPE)
1460     {
1461       if (!COMPLETE_TYPE_P (type))
1462         {
1463           c_incomplete_type_error (NULL_TREE, type);
1464           return error_mark_node;
1465         }
1466
1467       field = lookup_field (datum, component);
1468
1469       if (!field)
1470         {
1471           error ("%s has no member named `%s'",
1472                  code == RECORD_TYPE ? "structure" : "union",
1473                  IDENTIFIER_POINTER (component));
1474           return error_mark_node;
1475         }
1476
1477       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1478          This might be better solved in future the way the C++ front
1479          end does it - by giving the anonymous entities each a
1480          separate name and type, and then have build_component_ref
1481          recursively call itself.  We can't do that here.  */
1482       do
1483         {
1484           tree subdatum = TREE_VALUE (field);
1485
1486           if (TREE_TYPE (subdatum) == error_mark_node)
1487             return error_mark_node;
1488
1489           ref = build (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum);
1490           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1491             TREE_READONLY (ref) = 1;
1492           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1493             TREE_THIS_VOLATILE (ref) = 1;
1494
1495           if (TREE_DEPRECATED (subdatum))
1496             warn_deprecated_use (subdatum);
1497
1498           datum = ref;
1499
1500           field = TREE_CHAIN (field);
1501         }
1502       while (field);
1503
1504       return ref;
1505     }
1506   else if (code != ERROR_MARK)
1507     error ("request for member `%s' in something not a structure or union",
1508             IDENTIFIER_POINTER (component));
1509
1510   return error_mark_node;
1511 }
1512 \f
1513 /* Given an expression PTR for a pointer, return an expression
1514    for the value pointed to.
1515    ERRORSTRING is the name of the operator to appear in error messages.  */
1516
1517 tree
1518 build_indirect_ref (tree ptr, const char *errorstring)
1519 {
1520   tree pointer = default_conversion (ptr);
1521   tree type = TREE_TYPE (pointer);
1522
1523   if (TREE_CODE (type) == POINTER_TYPE)
1524     {
1525       if (TREE_CODE (pointer) == ADDR_EXPR
1526           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1527               == TREE_TYPE (type)))
1528         return TREE_OPERAND (pointer, 0);
1529       else
1530         {
1531           tree t = TREE_TYPE (type);
1532           tree ref = build1 (INDIRECT_REF, TYPE_MAIN_VARIANT (t), pointer);
1533
1534           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1535             {
1536               error ("dereferencing pointer to incomplete type");
1537               return error_mark_node;
1538             }
1539           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1540             warning ("dereferencing `void *' pointer");
1541
1542           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1543              so that we get the proper error message if the result is used
1544              to assign to.  Also, &* is supposed to be a no-op.
1545              And ANSI C seems to specify that the type of the result
1546              should be the const type.  */
1547           /* A de-reference of a pointer to const is not a const.  It is valid
1548              to change it via some other pointer.  */
1549           TREE_READONLY (ref) = TYPE_READONLY (t);
1550           TREE_SIDE_EFFECTS (ref)
1551             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1552           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1553           return ref;
1554         }
1555     }
1556   else if (TREE_CODE (pointer) != ERROR_MARK)
1557     error ("invalid type argument of `%s'", errorstring);
1558   return error_mark_node;
1559 }
1560
1561 /* This handles expressions of the form "a[i]", which denotes
1562    an array reference.
1563
1564    This is logically equivalent in C to *(a+i), but we may do it differently.
1565    If A is a variable or a member, we generate a primitive ARRAY_REF.
1566    This avoids forcing the array out of registers, and can work on
1567    arrays that are not lvalues (for example, members of structures returned
1568    by functions).  */
1569
1570 tree
1571 build_array_ref (tree array, tree index)
1572 {
1573   if (index == 0)
1574     {
1575       error ("subscript missing in array reference");
1576       return error_mark_node;
1577     }
1578
1579   if (TREE_TYPE (array) == error_mark_node
1580       || TREE_TYPE (index) == error_mark_node)
1581     return error_mark_node;
1582
1583   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1584     {
1585       tree rval, type;
1586
1587       /* Subscripting with type char is likely to lose
1588          on a machine where chars are signed.
1589          So warn on any machine, but optionally.
1590          Don't warn for unsigned char since that type is safe.
1591          Don't warn for signed char because anyone who uses that
1592          must have done so deliberately.  */
1593       if (warn_char_subscripts
1594           && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1595         warning ("array subscript has type `char'");
1596
1597       /* Apply default promotions *after* noticing character types.  */
1598       index = default_conversion (index);
1599
1600       /* Require integer *after* promotion, for sake of enums.  */
1601       if (TREE_CODE (TREE_TYPE (index)) != INTEGER_TYPE)
1602         {
1603           error ("array subscript is not an integer");
1604           return error_mark_node;
1605         }
1606
1607       /* An array that is indexed by a non-constant
1608          cannot be stored in a register; we must be able to do
1609          address arithmetic on its address.
1610          Likewise an array of elements of variable size.  */
1611       if (TREE_CODE (index) != INTEGER_CST
1612           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1613               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1614         {
1615           if (!c_mark_addressable (array))
1616             return error_mark_node;
1617         }
1618       /* An array that is indexed by a constant value which is not within
1619          the array bounds cannot be stored in a register either; because we
1620          would get a crash in store_bit_field/extract_bit_field when trying
1621          to access a non-existent part of the register.  */
1622       if (TREE_CODE (index) == INTEGER_CST
1623           && TYPE_DOMAIN (TREE_TYPE (array))
1624           && ! int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1625         {
1626           if (!c_mark_addressable (array))
1627             return error_mark_node;
1628         }
1629
1630       if (pedantic)
1631         {
1632           tree foo = array;
1633           while (TREE_CODE (foo) == COMPONENT_REF)
1634             foo = TREE_OPERAND (foo, 0);
1635           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1636             pedwarn ("ISO C forbids subscripting `register' array");
1637           else if (! flag_isoc99 && ! lvalue_p (foo))
1638             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1639         }
1640
1641       type = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (array)));
1642       rval = build (ARRAY_REF, type, array, index);
1643       /* Array ref is const/volatile if the array elements are
1644          or if the array is.  */
1645       TREE_READONLY (rval)
1646         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1647             | TREE_READONLY (array));
1648       TREE_SIDE_EFFECTS (rval)
1649         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1650             | TREE_SIDE_EFFECTS (array));
1651       TREE_THIS_VOLATILE (rval)
1652         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1653             /* This was added by rms on 16 Nov 91.
1654                It fixes  vol struct foo *a;  a->elts[1]
1655                in an inline function.
1656                Hope it doesn't break something else.  */
1657             | TREE_THIS_VOLATILE (array));
1658       return require_complete_type (fold (rval));
1659     }
1660
1661   {
1662     tree ar = default_conversion (array);
1663     tree ind = default_conversion (index);
1664
1665     /* Do the same warning check as above, but only on the part that's
1666        syntactically the index and only if it is also semantically
1667        the index.  */
1668     if (warn_char_subscripts
1669         && TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE
1670         && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1671       warning ("subscript has type `char'");
1672
1673     /* Put the integer in IND to simplify error checking.  */
1674     if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
1675       {
1676         tree temp = ar;
1677         ar = ind;
1678         ind = temp;
1679       }
1680
1681     if (ar == error_mark_node)
1682       return ar;
1683
1684     if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE
1685         || TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) == FUNCTION_TYPE)
1686       {
1687         error ("subscripted value is neither array nor pointer");
1688         return error_mark_node;
1689       }
1690     if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
1691       {
1692         error ("array subscript is not an integer");
1693         return error_mark_node;
1694       }
1695
1696     return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, ind, 0),
1697                                "array indexing");
1698   }
1699 }
1700 \f
1701 /* Build an external reference to identifier ID.  FUN indicates
1702    whether this will be used for a function call.  */
1703 tree
1704 build_external_ref (tree id, int fun)
1705 {
1706   tree ref;
1707   tree decl = lookup_name (id);
1708   tree objc_ivar = lookup_objc_ivar (id);
1709
1710   if (decl && decl != error_mark_node)
1711     {
1712       /* Properly declared variable or function reference.  */
1713       if (!objc_ivar)
1714         ref = decl;
1715       else if (decl != objc_ivar && !DECL_FILE_SCOPE_P (decl))
1716         {
1717           warning ("local declaration of `%s' hides instance variable",
1718                    IDENTIFIER_POINTER (id));
1719           ref = decl;
1720         }
1721       else
1722         ref = objc_ivar;
1723     }
1724   else if (objc_ivar)
1725     ref = objc_ivar;
1726   else if (fun)
1727     /* Implicit function declaration.  */
1728     ref = implicitly_declare (id);
1729   else if (decl == error_mark_node)
1730     /* Don't complain about something that's already been
1731        complained about.  */
1732     return error_mark_node;
1733   else
1734     {
1735       undeclared_variable (id);
1736       return error_mark_node;
1737     }
1738
1739   if (TREE_TYPE (ref) == error_mark_node)
1740     return error_mark_node;
1741
1742   if (TREE_DEPRECATED (ref))
1743     warn_deprecated_use (ref);
1744
1745   if (!skip_evaluation)
1746     assemble_external (ref);
1747   TREE_USED (ref) = 1;
1748
1749   if (TREE_CODE (ref) == CONST_DECL)
1750     {
1751       ref = DECL_INITIAL (ref);
1752       TREE_CONSTANT (ref) = 1;
1753       TREE_INVARIANT (ref) = 1;
1754     }
1755   else if (current_function_decl != 0
1756            && !DECL_FILE_SCOPE_P (current_function_decl)
1757            && (TREE_CODE (ref) == VAR_DECL
1758                || TREE_CODE (ref) == PARM_DECL
1759                || TREE_CODE (ref) == FUNCTION_DECL))
1760     {
1761       tree context = decl_function_context (ref);
1762
1763       if (context != 0 && context != current_function_decl)
1764         DECL_NONLOCAL (ref) = 1;
1765     }
1766
1767   return ref;
1768 }
1769
1770 /* Build a function call to function FUNCTION with parameters PARAMS.
1771    PARAMS is a list--a chain of TREE_LIST nodes--in which the
1772    TREE_VALUE of each node is a parameter-expression.
1773    FUNCTION's data type may be a function type or a pointer-to-function.  */
1774
1775 tree
1776 build_function_call (tree function, tree params)
1777 {
1778   tree fntype, fundecl = 0;
1779   tree coerced_params;
1780   tree name = NULL_TREE, result;
1781   tree tem;
1782
1783   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
1784   STRIP_TYPE_NOPS (function);
1785
1786   /* Convert anything with function type to a pointer-to-function.  */
1787   if (TREE_CODE (function) == FUNCTION_DECL)
1788     {
1789       name = DECL_NAME (function);
1790
1791       /* Differs from default_conversion by not setting TREE_ADDRESSABLE
1792          (because calling an inline function does not mean the function
1793          needs to be separately compiled).  */
1794       fntype = build_type_variant (TREE_TYPE (function),
1795                                    TREE_READONLY (function),
1796                                    TREE_THIS_VOLATILE (function));
1797       fundecl = function;
1798       function = build1 (ADDR_EXPR, build_pointer_type (fntype), function);
1799     }
1800   else
1801     function = default_conversion (function);
1802
1803   fntype = TREE_TYPE (function);
1804
1805   if (TREE_CODE (fntype) == ERROR_MARK)
1806     return error_mark_node;
1807
1808   if (!(TREE_CODE (fntype) == POINTER_TYPE
1809         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
1810     {
1811       error ("called object is not a function");
1812       return error_mark_node;
1813     }
1814
1815   if (fundecl && TREE_THIS_VOLATILE (fundecl))
1816     current_function_returns_abnormally = 1;
1817
1818   /* fntype now gets the type of function pointed to.  */
1819   fntype = TREE_TYPE (fntype);
1820
1821   /* Check that the function is called through a compatible prototype.
1822      If it is not, replace the call by a trap, wrapped up in a compound
1823      expression if necessary.  This has the nice side-effect to prevent
1824      the tree-inliner from generating invalid assignment trees which may
1825      blow up in the RTL expander later.
1826
1827      ??? This doesn't work for Objective-C because objc_comptypes
1828      refuses to compare function prototypes, yet the compiler appears
1829      to build calls that are flagged as invalid by C's comptypes.  */
1830   if (! c_dialect_objc ()
1831       && TREE_CODE (function) == NOP_EXPR
1832       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
1833       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
1834       && ! comptypes (fntype, TREE_TYPE (tem)))
1835     {
1836       tree return_type = TREE_TYPE (fntype);
1837       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
1838                                        NULL_TREE);
1839
1840       /* This situation leads to run-time undefined behavior.  We can't,
1841          therefore, simply error unless we can prove that all possible
1842          executions of the program must execute the code.  */
1843       warning ("function called through a non-compatible type");
1844
1845       /* We can, however, treat "undefined" any way we please.
1846          Call abort to encourage the user to fix the program.  */
1847       inform ("if this code is reached, the program will abort");
1848
1849       if (VOID_TYPE_P (return_type))
1850         return trap;
1851       else
1852         {
1853           tree rhs;
1854
1855           if (AGGREGATE_TYPE_P (return_type))
1856             rhs = build_compound_literal (return_type,
1857                                           build_constructor (return_type,
1858                                                              NULL_TREE));
1859           else
1860             rhs = fold (build1 (NOP_EXPR, return_type, integer_zero_node));
1861
1862           return build (COMPOUND_EXPR, return_type, trap, rhs);
1863         }
1864     }
1865
1866   /* Convert the parameters to the types declared in the
1867      function prototype, or apply default promotions.  */
1868
1869   coerced_params
1870     = convert_arguments (TYPE_ARG_TYPES (fntype), params, name, fundecl);
1871
1872   /* Check that the arguments to the function are valid.  */
1873
1874   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params);
1875
1876   /* Recognize certain built-in functions so we can make tree-codes
1877      other than CALL_EXPR.  We do this when it enables fold-const.c
1878      to do something useful.  */
1879
1880   if (TREE_CODE (function) == ADDR_EXPR
1881       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL
1882       && DECL_BUILT_IN (TREE_OPERAND (function, 0)))
1883     {
1884       result = expand_tree_builtin (TREE_OPERAND (function, 0),
1885                                     params, coerced_params);
1886       if (result)
1887         return result;
1888     }
1889
1890   result = build (CALL_EXPR, TREE_TYPE (fntype),
1891                   function, coerced_params, NULL_TREE);
1892   TREE_SIDE_EFFECTS (result) = 1;
1893
1894   if (require_constant_value)
1895     {
1896       result = fold_initializer (result);
1897
1898       if (TREE_CONSTANT (result)
1899           && (name == NULL_TREE
1900               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
1901         pedwarn_init ("initializer element is not constant");
1902     }
1903   else
1904     result = fold (result);
1905
1906   if (VOID_TYPE_P (TREE_TYPE (result)))
1907     return result;
1908   return require_complete_type (result);
1909 }
1910 \f
1911 /* Convert the argument expressions in the list VALUES
1912    to the types in the list TYPELIST.  The result is a list of converted
1913    argument expressions.
1914
1915    If TYPELIST is exhausted, or when an element has NULL as its type,
1916    perform the default conversions.
1917
1918    PARMLIST is the chain of parm decls for the function being called.
1919    It may be 0, if that info is not available.
1920    It is used only for generating error messages.
1921
1922    NAME is an IDENTIFIER_NODE or 0.  It is used only for error messages.
1923
1924    This is also where warnings about wrong number of args are generated.
1925
1926    Both VALUES and the returned value are chains of TREE_LIST nodes
1927    with the elements of the list in the TREE_VALUE slots of those nodes.  */
1928
1929 static tree
1930 convert_arguments (tree typelist, tree values, tree name, tree fundecl)
1931 {
1932   tree typetail, valtail;
1933   tree result = NULL;
1934   int parmnum;
1935
1936   /* Scan the given expressions and types, producing individual
1937      converted arguments and pushing them on RESULT in reverse order.  */
1938
1939   for (valtail = values, typetail = typelist, parmnum = 0;
1940        valtail;
1941        valtail = TREE_CHAIN (valtail), parmnum++)
1942     {
1943       tree type = typetail ? TREE_VALUE (typetail) : 0;
1944       tree val = TREE_VALUE (valtail);
1945
1946       if (type == void_type_node)
1947         {
1948           if (name)
1949             error ("too many arguments to function `%s'",
1950                    IDENTIFIER_POINTER (name));
1951           else
1952             error ("too many arguments to function");
1953           break;
1954         }
1955
1956       /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
1957       /* Do not use STRIP_NOPS here!  We do not want an enumerator with value 0
1958          to convert automatically to a pointer.  */
1959       if (TREE_CODE (val) == NON_LVALUE_EXPR)
1960         val = TREE_OPERAND (val, 0);
1961
1962       val = default_function_array_conversion (val);
1963
1964       val = require_complete_type (val);
1965
1966       if (type != 0)
1967         {
1968           /* Formal parm type is specified by a function prototype.  */
1969           tree parmval;
1970
1971           if (!COMPLETE_TYPE_P (type))
1972             {
1973               error ("type of formal parameter %d is incomplete", parmnum + 1);
1974               parmval = val;
1975             }
1976           else
1977             {
1978               /* Optionally warn about conversions that
1979                  differ from the default conversions.  */
1980               if (warn_conversion || warn_traditional)
1981                 {
1982                   int formal_prec = TYPE_PRECISION (type);
1983
1984                   if (INTEGRAL_TYPE_P (type)
1985                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
1986                     warn_for_assignment ("%s as integer rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1987                   if (INTEGRAL_TYPE_P (type)
1988                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
1989                     warn_for_assignment ("%s as integer rather than complex due to prototype", (char *) 0, name, parmnum + 1);
1990                   else if (TREE_CODE (type) == COMPLEX_TYPE
1991                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
1992                     warn_for_assignment ("%s as complex rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1993                   else if (TREE_CODE (type) == REAL_TYPE
1994                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
1995                     warn_for_assignment ("%s as floating rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1996                   else if (TREE_CODE (type) == COMPLEX_TYPE
1997                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
1998                     warn_for_assignment ("%s as complex rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1999                   else if (TREE_CODE (type) == REAL_TYPE
2000                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2001                     warn_for_assignment ("%s as floating rather than complex due to prototype", (char *) 0, name, parmnum + 1);
2002                   /* ??? At some point, messages should be written about
2003                      conversions between complex types, but that's too messy
2004                      to do now.  */
2005                   else if (TREE_CODE (type) == REAL_TYPE
2006                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2007                     {
2008                       /* Warn if any argument is passed as `float',
2009                          since without a prototype it would be `double'.  */
2010                       if (formal_prec == TYPE_PRECISION (float_type_node))
2011                         warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
2012                     }
2013                   /* Detect integer changing in width or signedness.
2014                      These warnings are only activated with
2015                      -Wconversion, not with -Wtraditional.  */
2016                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2017                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2018                     {
2019                       tree would_have_been = default_conversion (val);
2020                       tree type1 = TREE_TYPE (would_have_been);
2021
2022                       if (TREE_CODE (type) == ENUMERAL_TYPE
2023                           && (TYPE_MAIN_VARIANT (type)
2024                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2025                         /* No warning if function asks for enum
2026                            and the actual arg is that enum type.  */
2027                         ;
2028                       else if (formal_prec != TYPE_PRECISION (type1))
2029                         warn_for_assignment ("%s with different width due to prototype", (char *) 0, name, parmnum + 1);
2030                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2031                         ;
2032                       /* Don't complain if the formal parameter type
2033                          is an enum, because we can't tell now whether
2034                          the value was an enum--even the same enum.  */
2035                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2036                         ;
2037                       else if (TREE_CODE (val) == INTEGER_CST
2038                                && int_fits_type_p (val, type))
2039                         /* Change in signedness doesn't matter
2040                            if a constant value is unaffected.  */
2041                         ;
2042                       /* Likewise for a constant in a NOP_EXPR.  */
2043                       else if (TREE_CODE (val) == NOP_EXPR
2044                                && TREE_CODE (TREE_OPERAND (val, 0)) == INTEGER_CST
2045                                && int_fits_type_p (TREE_OPERAND (val, 0), type))
2046                         ;
2047                       /* If the value is extended from a narrower
2048                          unsigned type, it doesn't matter whether we
2049                          pass it as signed or unsigned; the value
2050                          certainly is the same either way.  */
2051                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2052                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2053                         ;
2054                       else if (TYPE_UNSIGNED (type))
2055                         warn_for_assignment ("%s as unsigned due to prototype", (char *) 0, name, parmnum + 1);
2056                       else
2057                         warn_for_assignment ("%s as signed due to prototype", (char *) 0, name, parmnum + 1);
2058                     }
2059                 }
2060
2061               parmval = convert_for_assignment (type, val,
2062                                                 (char *) 0, /* arg passing  */
2063                                                 fundecl, name, parmnum + 1);
2064
2065               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2066                   && INTEGRAL_TYPE_P (type)
2067                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2068                 parmval = default_conversion (parmval);
2069             }
2070           result = tree_cons (NULL_TREE, parmval, result);
2071         }
2072       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2073                && (TYPE_PRECISION (TREE_TYPE (val))
2074                    < TYPE_PRECISION (double_type_node)))
2075         /* Convert `float' to `double'.  */
2076         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2077       else
2078         /* Convert `short' and `char' to full-size `int'.  */
2079         result = tree_cons (NULL_TREE, default_conversion (val), result);
2080
2081       if (typetail)
2082         typetail = TREE_CHAIN (typetail);
2083     }
2084
2085   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2086     {
2087       if (name)
2088         error ("too few arguments to function `%s'",
2089                IDENTIFIER_POINTER (name));
2090       else
2091         error ("too few arguments to function");
2092     }
2093
2094   return nreverse (result);
2095 }
2096 \f
2097 /* This is the entry point used by the parser
2098    for binary operators in the input.
2099    In addition to constructing the expression,
2100    we check for operands that were written with other binary operators
2101    in a way that is likely to confuse the user.  */
2102
2103 tree
2104 parser_build_binary_op (enum tree_code code, tree arg1, tree arg2)
2105 {
2106   tree result = build_binary_op (code, arg1, arg2, 1);
2107
2108   char class;
2109   char class1 = TREE_CODE_CLASS (TREE_CODE (arg1));
2110   char class2 = TREE_CODE_CLASS (TREE_CODE (arg2));
2111   enum tree_code code1 = ERROR_MARK;
2112   enum tree_code code2 = ERROR_MARK;
2113
2114   if (TREE_CODE (result) == ERROR_MARK)
2115     return error_mark_node;
2116
2117   if (IS_EXPR_CODE_CLASS (class1))
2118     code1 = C_EXP_ORIGINAL_CODE (arg1);
2119   if (IS_EXPR_CODE_CLASS (class2))
2120     code2 = C_EXP_ORIGINAL_CODE (arg2);
2121
2122   /* Check for cases such as x+y<<z which users are likely
2123      to misinterpret.  If parens are used, C_EXP_ORIGINAL_CODE
2124      is cleared to prevent these warnings.  */
2125   if (warn_parentheses)
2126     {
2127       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2128         {
2129           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2130               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2131             warning ("suggest parentheses around + or - inside shift");
2132         }
2133
2134       if (code == TRUTH_ORIF_EXPR)
2135         {
2136           if (code1 == TRUTH_ANDIF_EXPR
2137               || code2 == TRUTH_ANDIF_EXPR)
2138             warning ("suggest parentheses around && within ||");
2139         }
2140
2141       if (code == BIT_IOR_EXPR)
2142         {
2143           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2144               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2145               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2146               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2147             warning ("suggest parentheses around arithmetic in operand of |");
2148           /* Check cases like x|y==z */
2149           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2150             warning ("suggest parentheses around comparison in operand of |");
2151         }
2152
2153       if (code == BIT_XOR_EXPR)
2154         {
2155           if (code1 == BIT_AND_EXPR
2156               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2157               || code2 == BIT_AND_EXPR
2158               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2159             warning ("suggest parentheses around arithmetic in operand of ^");
2160           /* Check cases like x^y==z */
2161           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2162             warning ("suggest parentheses around comparison in operand of ^");
2163         }
2164
2165       if (code == BIT_AND_EXPR)
2166         {
2167           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2168               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2169             warning ("suggest parentheses around + or - in operand of &");
2170           /* Check cases like x&y==z */
2171           if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
2172             warning ("suggest parentheses around comparison in operand of &");
2173         }
2174     }
2175
2176   /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2177   if (TREE_CODE_CLASS (code) == '<' && extra_warnings
2178       && (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<'))
2179     warning ("comparisons like X<=Y<=Z do not have their mathematical meaning");
2180
2181   unsigned_conversion_warning (result, arg1);
2182   unsigned_conversion_warning (result, arg2);
2183   overflow_warning (result);
2184
2185   class = TREE_CODE_CLASS (TREE_CODE (result));
2186
2187   /* Record the code that was specified in the source,
2188      for the sake of warnings about confusing nesting.  */
2189   if (IS_EXPR_CODE_CLASS (class))
2190     C_SET_EXP_ORIGINAL_CODE (result, code);
2191   else
2192     {
2193       /* We used to use NOP_EXPR rather than NON_LVALUE_EXPR
2194          so that convert_for_assignment wouldn't strip it.
2195          That way, we got warnings for things like p = (1 - 1).
2196          But it turns out we should not get those warnings.  */
2197       result = build1 (NON_LVALUE_EXPR, TREE_TYPE (result), result);
2198       C_SET_EXP_ORIGINAL_CODE (result, code);
2199     }
2200
2201   return result;
2202 }
2203 \f
2204
2205 /* Return true if `t' is known to be non-negative.  */
2206
2207 int
2208 c_tree_expr_nonnegative_p (tree t)
2209 {
2210   if (TREE_CODE (t) == STMT_EXPR)
2211     t = expr_last (STMT_EXPR_STMT (t));
2212   return tree_expr_nonnegative_p (t);
2213 }
2214
2215 /* Return a tree for the difference of pointers OP0 and OP1.
2216    The resulting tree has type int.  */
2217
2218 static tree
2219 pointer_diff (tree op0, tree op1)
2220 {
2221   tree restype = ptrdiff_type_node;
2222
2223   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2224   tree con0, con1, lit0, lit1;
2225   tree orig_op1 = op1;
2226
2227   if (pedantic || warn_pointer_arith)
2228     {
2229       if (TREE_CODE (target_type) == VOID_TYPE)
2230         pedwarn ("pointer of type `void *' used in subtraction");
2231       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2232         pedwarn ("pointer to a function used in subtraction");
2233     }
2234
2235   /* If the conversion to ptrdiff_type does anything like widening or
2236      converting a partial to an integral mode, we get a convert_expression
2237      that is in the way to do any simplifications.
2238      (fold-const.c doesn't know that the extra bits won't be needed.
2239      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2240      different mode in place.)
2241      So first try to find a common term here 'by hand'; we want to cover
2242      at least the cases that occur in legal static initializers.  */
2243   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2244   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2245
2246   if (TREE_CODE (con0) == PLUS_EXPR)
2247     {
2248       lit0 = TREE_OPERAND (con0, 1);
2249       con0 = TREE_OPERAND (con0, 0);
2250     }
2251   else
2252     lit0 = integer_zero_node;
2253
2254   if (TREE_CODE (con1) == PLUS_EXPR)
2255     {
2256       lit1 = TREE_OPERAND (con1, 1);
2257       con1 = TREE_OPERAND (con1, 0);
2258     }
2259   else
2260     lit1 = integer_zero_node;
2261
2262   if (operand_equal_p (con0, con1, 0))
2263     {
2264       op0 = lit0;
2265       op1 = lit1;
2266     }
2267
2268
2269   /* First do the subtraction as integers;
2270      then drop through to build the divide operator.
2271      Do not do default conversions on the minus operator
2272      in case restype is a short type.  */
2273
2274   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2275                          convert (restype, op1), 0);
2276   /* This generates an error if op1 is pointer to incomplete type.  */
2277   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2278     error ("arithmetic on pointer to an incomplete type");
2279
2280   /* This generates an error if op0 is pointer to incomplete type.  */
2281   op1 = c_size_in_bytes (target_type);
2282
2283   /* Divide by the size, in easiest possible way.  */
2284   return fold (build (EXACT_DIV_EXPR, restype, op0, convert (restype, op1)));
2285 }
2286 \f
2287 /* Construct and perhaps optimize a tree representation
2288    for a unary operation.  CODE, a tree_code, specifies the operation
2289    and XARG is the operand.
2290    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2291    the default promotions (such as from short to int).
2292    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2293    allows non-lvalues; this is only used to handle conversion of non-lvalue
2294    arrays to pointers in C99.  */
2295
2296 tree
2297 build_unary_op (enum tree_code code, tree xarg, int flag)
2298 {
2299   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2300   tree arg = xarg;
2301   tree argtype = 0;
2302   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2303   tree val;
2304   int noconvert = flag;
2305
2306   if (typecode == ERROR_MARK)
2307     return error_mark_node;
2308   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2309     typecode = INTEGER_TYPE;
2310
2311   switch (code)
2312     {
2313     case CONVERT_EXPR:
2314       /* This is used for unary plus, because a CONVERT_EXPR
2315          is enough to prevent anybody from looking inside for
2316          associativity, but won't generate any code.  */
2317       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2318             || typecode == COMPLEX_TYPE))
2319         {
2320           error ("wrong type argument to unary plus");
2321           return error_mark_node;
2322         }
2323       else if (!noconvert)
2324         arg = default_conversion (arg);
2325       arg = non_lvalue (arg);
2326       break;
2327
2328     case NEGATE_EXPR:
2329       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2330             || typecode == COMPLEX_TYPE
2331             || typecode == VECTOR_TYPE))
2332         {
2333           error ("wrong type argument to unary minus");
2334           return error_mark_node;
2335         }
2336       else if (!noconvert)
2337         arg = default_conversion (arg);
2338       break;
2339
2340     case BIT_NOT_EXPR:
2341       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2342         {
2343           if (!noconvert)
2344             arg = default_conversion (arg);
2345         }
2346       else if (typecode == COMPLEX_TYPE)
2347         {
2348           code = CONJ_EXPR;
2349           if (pedantic)
2350             pedwarn ("ISO C does not support `~' for complex conjugation");
2351           if (!noconvert)
2352             arg = default_conversion (arg);
2353         }
2354       else
2355         {
2356           error ("wrong type argument to bit-complement");
2357           return error_mark_node;
2358         }
2359       break;
2360
2361     case ABS_EXPR:
2362       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2363         {
2364           error ("wrong type argument to abs");
2365           return error_mark_node;
2366         }
2367       else if (!noconvert)
2368         arg = default_conversion (arg);
2369       break;
2370
2371     case CONJ_EXPR:
2372       /* Conjugating a real value is a no-op, but allow it anyway.  */
2373       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2374             || typecode == COMPLEX_TYPE))
2375         {
2376           error ("wrong type argument to conjugation");
2377           return error_mark_node;
2378         }
2379       else if (!noconvert)
2380         arg = default_conversion (arg);
2381       break;
2382
2383     case TRUTH_NOT_EXPR:
2384       if (typecode != INTEGER_TYPE
2385           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2386           && typecode != COMPLEX_TYPE
2387           /* These will convert to a pointer.  */
2388           && typecode != ARRAY_TYPE && typecode != FUNCTION_TYPE)
2389         {
2390           error ("wrong type argument to unary exclamation mark");
2391           return error_mark_node;
2392         }
2393       arg = lang_hooks.truthvalue_conversion (arg);
2394       return invert_truthvalue (arg);
2395
2396     case NOP_EXPR:
2397       break;
2398
2399     case REALPART_EXPR:
2400       if (TREE_CODE (arg) == COMPLEX_CST)
2401         return TREE_REALPART (arg);
2402       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2403         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2404       else
2405         return arg;
2406
2407     case IMAGPART_EXPR:
2408       if (TREE_CODE (arg) == COMPLEX_CST)
2409         return TREE_IMAGPART (arg);
2410       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2411         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
2412       else
2413         return convert (TREE_TYPE (arg), integer_zero_node);
2414
2415     case PREINCREMENT_EXPR:
2416     case POSTINCREMENT_EXPR:
2417     case PREDECREMENT_EXPR:
2418     case POSTDECREMENT_EXPR:
2419
2420       /* Increment or decrement the real part of the value,
2421          and don't change the imaginary part.  */
2422       if (typecode == COMPLEX_TYPE)
2423         {
2424           tree real, imag;
2425
2426           if (pedantic)
2427             pedwarn ("ISO C does not support `++' and `--' on complex types");
2428
2429           arg = stabilize_reference (arg);
2430           real = build_unary_op (REALPART_EXPR, arg, 1);
2431           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2432           return build (COMPLEX_EXPR, TREE_TYPE (arg),
2433                         build_unary_op (code, real, 1), imag);
2434         }
2435
2436       /* Report invalid types.  */
2437
2438       if (typecode != POINTER_TYPE
2439           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2440         {
2441           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2442             error ("wrong type argument to increment");
2443           else
2444             error ("wrong type argument to decrement");
2445
2446           return error_mark_node;
2447         }
2448
2449       {
2450         tree inc;
2451         tree result_type = TREE_TYPE (arg);
2452
2453         arg = get_unwidened (arg, 0);
2454         argtype = TREE_TYPE (arg);
2455
2456         /* Compute the increment.  */
2457
2458         if (typecode == POINTER_TYPE)
2459           {
2460             /* If pointer target is an undefined struct,
2461                we just cannot know how to do the arithmetic.  */
2462             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2463               {
2464                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2465                   error ("increment of pointer to unknown structure");
2466                 else
2467                   error ("decrement of pointer to unknown structure");
2468               }
2469             else if ((pedantic || warn_pointer_arith)
2470                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2471                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2472               {
2473                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2474                   pedwarn ("wrong type argument to increment");
2475                 else
2476                   pedwarn ("wrong type argument to decrement");
2477               }
2478
2479             inc = c_size_in_bytes (TREE_TYPE (result_type));
2480           }
2481         else
2482           inc = integer_one_node;
2483
2484         inc = convert (argtype, inc);
2485
2486         /* Complain about anything else that is not a true lvalue.  */
2487         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2488                                     || code == POSTINCREMENT_EXPR)
2489                                    ? "invalid lvalue in increment"
2490                                    : "invalid lvalue in decrement")))
2491           return error_mark_node;
2492
2493         /* Report a read-only lvalue.  */
2494         if (TREE_READONLY (arg))
2495           readonly_error (arg,
2496                           ((code == PREINCREMENT_EXPR
2497                             || code == POSTINCREMENT_EXPR)
2498                            ? "increment" : "decrement"));
2499
2500         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2501           val = boolean_increment (code, arg);
2502         else
2503           val = build (code, TREE_TYPE (arg), arg, inc);
2504         TREE_SIDE_EFFECTS (val) = 1;
2505         val = convert (result_type, val);
2506         if (TREE_CODE (val) != code)
2507           TREE_NO_WARNING (val) = 1;
2508         return val;
2509       }
2510
2511     case ADDR_EXPR:
2512       /* Note that this operation never does default_conversion.  */
2513
2514       /* Let &* cancel out to simplify resulting code.  */
2515       if (TREE_CODE (arg) == INDIRECT_REF)
2516         {
2517           /* Don't let this be an lvalue.  */
2518           if (lvalue_p (TREE_OPERAND (arg, 0)))
2519             return non_lvalue (TREE_OPERAND (arg, 0));
2520           return TREE_OPERAND (arg, 0);
2521         }
2522
2523       /* For &x[y], return x+y */
2524       if (TREE_CODE (arg) == ARRAY_REF)
2525         {
2526           if (!c_mark_addressable (TREE_OPERAND (arg, 0)))
2527             return error_mark_node;
2528           return build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
2529                                   TREE_OPERAND (arg, 1), 1);
2530         }
2531
2532       /* Anything not already handled and not a true memory reference
2533          or a non-lvalue array is an error.  */
2534       else if (typecode != FUNCTION_TYPE && !flag
2535                && !lvalue_or_else (arg, "invalid lvalue in unary `&'"))
2536         return error_mark_node;
2537
2538       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2539       argtype = TREE_TYPE (arg);
2540
2541       /* If the lvalue is const or volatile, merge that into the type
2542          to which the address will point.  Note that you can't get a
2543          restricted pointer by taking the address of something, so we
2544          only have to deal with `const' and `volatile' here.  */
2545       if ((DECL_P (arg) || TREE_CODE_CLASS (TREE_CODE (arg)) == 'r')
2546           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2547           argtype = c_build_type_variant (argtype,
2548                                           TREE_READONLY (arg),
2549                                           TREE_THIS_VOLATILE (arg));
2550
2551       argtype = build_pointer_type (argtype);
2552
2553       if (!c_mark_addressable (arg))
2554         return error_mark_node;
2555
2556       {
2557         tree addr;
2558
2559         if (TREE_CODE (arg) == COMPONENT_REF)
2560           {
2561             tree field = TREE_OPERAND (arg, 1);
2562
2563             addr = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), flag);
2564
2565             if (DECL_C_BIT_FIELD (field))
2566               {
2567                 error ("attempt to take address of bit-field structure member `%s'",
2568                        IDENTIFIER_POINTER (DECL_NAME (field)));
2569                 return error_mark_node;
2570               }
2571
2572             addr = fold (build (PLUS_EXPR, argtype,
2573                                 convert (argtype, addr),
2574                                 convert (argtype, byte_position (field))));
2575           }
2576         else
2577           addr = build1 (code, argtype, arg);
2578
2579         return addr;
2580       }
2581
2582     default:
2583       break;
2584     }
2585
2586   if (argtype == 0)
2587     argtype = TREE_TYPE (arg);
2588   val = build1 (code, argtype, arg);
2589   return require_constant_value ? fold_initializer (val) : fold (val);
2590 }
2591
2592 /* Return nonzero if REF is an lvalue valid for this language.
2593    Lvalues can be assigned, unless their type has TYPE_READONLY.
2594    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2595
2596 int
2597 lvalue_p (tree ref)
2598 {
2599   enum tree_code code = TREE_CODE (ref);
2600
2601   switch (code)
2602     {
2603     case REALPART_EXPR:
2604     case IMAGPART_EXPR:
2605     case COMPONENT_REF:
2606       return lvalue_p (TREE_OPERAND (ref, 0));
2607
2608     case COMPOUND_LITERAL_EXPR:
2609     case STRING_CST:
2610       return 1;
2611
2612     case INDIRECT_REF:
2613     case ARRAY_REF:
2614     case VAR_DECL:
2615     case PARM_DECL:
2616     case RESULT_DECL:
2617     case ERROR_MARK:
2618       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2619               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2620
2621     case BIND_EXPR:
2622     case RTL_EXPR:
2623       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2624
2625     default:
2626       return 0;
2627     }
2628 }
2629
2630 /* Return nonzero if REF is an lvalue valid for this language;
2631    otherwise, print an error message and return zero.  */
2632
2633 static int
2634 lvalue_or_else (tree ref, const char *msgid)
2635 {
2636   int win = lvalue_p (ref);
2637
2638   if (! win)
2639     error ("%s", msgid);
2640
2641   return win;
2642 }
2643
2644 \f
2645 /* Warn about storing in something that is `const'.  */
2646
2647 void
2648 readonly_error (tree arg, const char *msgid)
2649 {
2650   if (TREE_CODE (arg) == COMPONENT_REF)
2651     {
2652       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2653         readonly_error (TREE_OPERAND (arg, 0), msgid);
2654       else
2655         error ("%s of read-only member `%s'", _(msgid),
2656                IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (arg, 1))));
2657     }
2658   else if (TREE_CODE (arg) == VAR_DECL)
2659     error ("%s of read-only variable `%s'", _(msgid),
2660            IDENTIFIER_POINTER (DECL_NAME (arg)));
2661   else
2662     error ("%s of read-only location", _(msgid));
2663 }
2664 \f
2665 /* Mark EXP saying that we need to be able to take the
2666    address of it; it should not be allocated in a register.
2667    Returns true if successful.  */
2668
2669 bool
2670 c_mark_addressable (tree exp)
2671 {
2672   tree x = exp;
2673
2674   while (1)
2675     switch (TREE_CODE (x))
2676       {
2677       case COMPONENT_REF:
2678         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
2679           {
2680             error ("cannot take address of bit-field `%s'",
2681                    IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (x, 1))));
2682             return false;
2683           }
2684
2685         /* ... fall through ...  */
2686
2687       case ADDR_EXPR:
2688       case ARRAY_REF:
2689       case REALPART_EXPR:
2690       case IMAGPART_EXPR:
2691         x = TREE_OPERAND (x, 0);
2692         break;
2693
2694       case COMPOUND_LITERAL_EXPR:
2695       case CONSTRUCTOR:
2696         TREE_ADDRESSABLE (x) = 1;
2697         return true;
2698
2699       case VAR_DECL:
2700       case CONST_DECL:
2701       case PARM_DECL:
2702       case RESULT_DECL:
2703         if (C_DECL_REGISTER (x)
2704             && DECL_NONLOCAL (x))
2705           {
2706             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2707               {
2708                 error ("global register variable `%s' used in nested function",
2709                        IDENTIFIER_POINTER (DECL_NAME (x)));
2710                 return false;
2711               }
2712             pedwarn ("register variable `%s' used in nested function",
2713                      IDENTIFIER_POINTER (DECL_NAME (x)));
2714           }
2715         else if (C_DECL_REGISTER (x))
2716           {
2717             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
2718               {
2719                 error ("address of global register variable `%s' requested",
2720                        IDENTIFIER_POINTER (DECL_NAME (x)));
2721                 return false;
2722               }
2723
2724             pedwarn ("address of register variable `%s' requested",
2725                      IDENTIFIER_POINTER (DECL_NAME (x)));
2726           }
2727         put_var_into_stack (x, /*rescan=*/true);
2728
2729         /* drops in */
2730       case FUNCTION_DECL:
2731         TREE_ADDRESSABLE (x) = 1;
2732         /* drops out */
2733       default:
2734         return true;
2735     }
2736 }
2737 \f
2738 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
2739
2740 tree
2741 build_conditional_expr (tree ifexp, tree op1, tree op2)
2742 {
2743   tree type1;
2744   tree type2;
2745   enum tree_code code1;
2746   enum tree_code code2;
2747   tree result_type = NULL;
2748   tree orig_op1 = op1, orig_op2 = op2;
2749
2750   ifexp = lang_hooks.truthvalue_conversion (default_conversion (ifexp));
2751
2752   /* Promote both alternatives.  */
2753
2754   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
2755     op1 = default_conversion (op1);
2756   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
2757     op2 = default_conversion (op2);
2758
2759   if (TREE_CODE (ifexp) == ERROR_MARK
2760       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
2761       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
2762     return error_mark_node;
2763
2764   type1 = TREE_TYPE (op1);
2765   code1 = TREE_CODE (type1);
2766   type2 = TREE_TYPE (op2);
2767   code2 = TREE_CODE (type2);
2768
2769   /* C90 does not permit non-lvalue arrays in conditional expressions.
2770      In C99 they will be pointers by now.  */
2771   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
2772     {
2773       error ("non-lvalue array in conditional expression");
2774       return error_mark_node;
2775     }
2776
2777   /* Quickly detect the usual case where op1 and op2 have the same type
2778      after promotion.  */
2779   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
2780     {
2781       if (type1 == type2)
2782         result_type = type1;
2783       else
2784         result_type = TYPE_MAIN_VARIANT (type1);
2785     }
2786   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
2787             || code1 == COMPLEX_TYPE)
2788            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
2789                || code2 == COMPLEX_TYPE))
2790     {
2791       result_type = common_type (type1, type2);
2792
2793       /* If -Wsign-compare, warn here if type1 and type2 have
2794          different signedness.  We'll promote the signed to unsigned
2795          and later code won't know it used to be different.
2796          Do this check on the original types, so that explicit casts
2797          will be considered, but default promotions won't.  */
2798       if (warn_sign_compare && !skip_evaluation)
2799         {
2800           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
2801           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
2802
2803           if (unsigned_op1 ^ unsigned_op2)
2804             {
2805               /* Do not warn if the result type is signed, since the
2806                  signed type will only be chosen if it can represent
2807                  all the values of the unsigned type.  */
2808               if (! TYPE_UNSIGNED (result_type))
2809                 /* OK */;
2810               /* Do not warn if the signed quantity is an unsuffixed
2811                  integer literal (or some static constant expression
2812                  involving such literals) and it is non-negative.  */
2813               else if ((unsigned_op2 && c_tree_expr_nonnegative_p (op1))
2814                        || (unsigned_op1 && c_tree_expr_nonnegative_p (op2)))
2815                 /* OK */;
2816               else
2817                 warning ("signed and unsigned type in conditional expression");
2818             }
2819         }
2820     }
2821   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
2822     {
2823       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
2824         pedwarn ("ISO C forbids conditional expr with only one void side");
2825       result_type = void_type_node;
2826     }
2827   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
2828     {
2829       if (comp_target_types (type1, type2, 1))
2830         result_type = common_pointer_type (type1, type2);
2831       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
2832                && TREE_CODE (orig_op1) != NOP_EXPR)
2833         result_type = qualify_type (type2, type1);
2834       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
2835                && TREE_CODE (orig_op2) != NOP_EXPR)
2836         result_type = qualify_type (type1, type2);
2837       else if (VOID_TYPE_P (TREE_TYPE (type1)))
2838         {
2839           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
2840             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2841           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
2842                                                           TREE_TYPE (type2)));
2843         }
2844       else if (VOID_TYPE_P (TREE_TYPE (type2)))
2845         {
2846           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
2847             pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
2848           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
2849                                                           TREE_TYPE (type1)));
2850         }
2851       else
2852         {
2853           pedwarn ("pointer type mismatch in conditional expression");
2854           result_type = build_pointer_type (void_type_node);
2855         }
2856     }
2857   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
2858     {
2859       if (! integer_zerop (op2))
2860         pedwarn ("pointer/integer type mismatch in conditional expression");
2861       else
2862         {
2863           op2 = null_pointer_node;
2864         }
2865       result_type = type1;
2866     }
2867   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
2868     {
2869       if (!integer_zerop (op1))
2870         pedwarn ("pointer/integer type mismatch in conditional expression");
2871       else
2872         {
2873           op1 = null_pointer_node;
2874         }
2875       result_type = type2;
2876     }
2877
2878   if (!result_type)
2879     {
2880       if (flag_cond_mismatch)
2881         result_type = void_type_node;
2882       else
2883         {
2884           error ("type mismatch in conditional expression");
2885           return error_mark_node;
2886         }
2887     }
2888
2889   /* Merge const and volatile flags of the incoming types.  */
2890   result_type
2891     = build_type_variant (result_type,
2892                           TREE_READONLY (op1) || TREE_READONLY (op2),
2893                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
2894
2895   if (result_type != TREE_TYPE (op1))
2896     op1 = convert_and_check (result_type, op1);
2897   if (result_type != TREE_TYPE (op2))
2898     op2 = convert_and_check (result_type, op2);
2899
2900   if (TREE_CODE (ifexp) == INTEGER_CST)
2901     return non_lvalue (integer_zerop (ifexp) ? op2 : op1);
2902
2903   return fold (build (COND_EXPR, result_type, ifexp, op1, op2));
2904 }
2905 \f
2906 /* Given a list of expressions, return a compound expression
2907    that performs them all and returns the value of the last of them.  */
2908
2909 tree
2910 build_compound_expr (tree list)
2911 {
2912   return internal_build_compound_expr (list, TRUE);
2913 }
2914
2915 static tree
2916 internal_build_compound_expr (tree list, int first_p)
2917 {
2918   tree rest;
2919
2920   if (TREE_CHAIN (list) == 0)
2921     {
2922       /* Convert arrays and functions to pointers when there
2923          really is a comma operator.  */
2924       if (!first_p)
2925         TREE_VALUE (list)
2926           = default_function_array_conversion (TREE_VALUE (list));
2927
2928       /* Don't let (0, 0) be null pointer constant.  */
2929       if (!first_p && integer_zerop (TREE_VALUE (list)))
2930         return non_lvalue (TREE_VALUE (list));
2931       return TREE_VALUE (list);
2932     }
2933
2934   rest = internal_build_compound_expr (TREE_CHAIN (list), FALSE);
2935
2936   if (! TREE_SIDE_EFFECTS (TREE_VALUE (list)))
2937     {
2938       /* The left-hand operand of a comma expression is like an expression
2939          statement: with -Wextra or -Wunused, we should warn if it doesn't have
2940          any side-effects, unless it was explicitly cast to (void).  */
2941       if (warn_unused_value
2942            && ! (TREE_CODE (TREE_VALUE (list)) == CONVERT_EXPR
2943                 && VOID_TYPE_P (TREE_TYPE (TREE_VALUE (list)))))
2944         warning ("left-hand operand of comma expression has no effect");
2945     }
2946
2947   /* With -Wunused, we should also warn if the left-hand operand does have
2948      side-effects, but computes a value which is not used.  For example, in
2949      `foo() + bar(), baz()' the result of the `+' operator is not used,
2950      so we should issue a warning.  */
2951   else if (warn_unused_value)
2952     warn_if_unused_value (TREE_VALUE (list), input_location);
2953
2954   return build (COMPOUND_EXPR, TREE_TYPE (rest), TREE_VALUE (list), rest);
2955 }
2956
2957 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
2958
2959 tree
2960 build_c_cast (tree type, tree expr)
2961 {
2962   tree value = expr;
2963
2964   if (type == error_mark_node || expr == error_mark_node)
2965     return error_mark_node;
2966
2967   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
2968      only in <protocol> qualifications.  But when constructing cast expressions,
2969      the protocols do matter and must be kept around.  */
2970   if (!c_dialect_objc () || !objc_is_object_ptr (type))
2971     type = TYPE_MAIN_VARIANT (type);
2972
2973   if (TREE_CODE (type) == ARRAY_TYPE)
2974     {
2975       error ("cast specifies array type");
2976       return error_mark_node;
2977     }
2978
2979   if (TREE_CODE (type) == FUNCTION_TYPE)
2980     {
2981       error ("cast specifies function type");
2982       return error_mark_node;
2983     }
2984
2985   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
2986     {
2987       if (pedantic)
2988         {
2989           if (TREE_CODE (type) == RECORD_TYPE
2990               || TREE_CODE (type) == UNION_TYPE)
2991             pedwarn ("ISO C forbids casting nonscalar to the same type");
2992         }
2993     }
2994   else if (TREE_CODE (type) == UNION_TYPE)
2995     {
2996       tree field;
2997       value = default_function_array_conversion (value);
2998
2999       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3000         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3001                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3002           break;
3003
3004       if (field)
3005         {
3006           tree t;
3007
3008           if (pedantic)
3009             pedwarn ("ISO C forbids casts to union type");
3010           t = digest_init (type,
3011                            build_constructor (type,
3012                                               build_tree_list (field, value)),
3013                            0);
3014           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3015           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3016           return t;
3017         }
3018       error ("cast to union type from type not present in union");
3019       return error_mark_node;
3020     }
3021   else
3022     {
3023       tree otype, ovalue;
3024
3025       /* If casting to void, avoid the error that would come
3026          from default_conversion in the case of a non-lvalue array.  */
3027       if (type == void_type_node)
3028         return build1 (CONVERT_EXPR, type, value);
3029
3030       /* Convert functions and arrays to pointers,
3031          but don't convert any other types.  */
3032       value = default_function_array_conversion (value);
3033       otype = TREE_TYPE (value);
3034
3035       /* Optionally warn about potentially worrisome casts.  */
3036
3037       if (warn_cast_qual
3038           && TREE_CODE (type) == POINTER_TYPE
3039           && TREE_CODE (otype) == POINTER_TYPE)
3040         {
3041           tree in_type = type;
3042           tree in_otype = otype;
3043           int added = 0;
3044           int discarded = 0;
3045
3046           /* Check that the qualifiers on IN_TYPE are a superset of
3047              the qualifiers of IN_OTYPE.  The outermost level of
3048              POINTER_TYPE nodes is uninteresting and we stop as soon
3049              as we hit a non-POINTER_TYPE node on either type.  */
3050           do
3051             {
3052               in_otype = TREE_TYPE (in_otype);
3053               in_type = TREE_TYPE (in_type);
3054
3055               /* GNU C allows cv-qualified function types.  'const'
3056                  means the function is very pure, 'volatile' means it
3057                  can't return.  We need to warn when such qualifiers
3058                  are added, not when they're taken away.  */
3059               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3060                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3061                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3062               else
3063                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3064             }
3065           while (TREE_CODE (in_type) == POINTER_TYPE
3066                  && TREE_CODE (in_otype) == POINTER_TYPE);
3067
3068           if (added)
3069             warning ("cast adds new qualifiers to function type");
3070
3071           if (discarded)
3072             /* There are qualifiers present in IN_OTYPE that are not
3073                present in IN_TYPE.  */
3074             warning ("cast discards qualifiers from pointer target type");
3075         }
3076
3077       /* Warn about possible alignment problems.  */
3078       if (STRICT_ALIGNMENT && warn_cast_align
3079           && TREE_CODE (type) == POINTER_TYPE
3080           && TREE_CODE (otype) == POINTER_TYPE
3081           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3082           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3083           /* Don't warn about opaque types, where the actual alignment
3084              restriction is unknown.  */
3085           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3086                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3087                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3088           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3089         warning ("cast increases required alignment of target type");
3090
3091       if (TREE_CODE (type) == INTEGER_TYPE
3092           && TREE_CODE (otype) == POINTER_TYPE
3093           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3094           && !TREE_CONSTANT (value))
3095         warning ("cast from pointer to integer of different size");
3096
3097       if (warn_bad_function_cast
3098           && TREE_CODE (value) == CALL_EXPR
3099           && TREE_CODE (type) != TREE_CODE (otype))
3100         warning ("cast does not match function type");
3101
3102       if (TREE_CODE (type) == POINTER_TYPE
3103           && TREE_CODE (otype) == INTEGER_TYPE
3104           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3105           /* Don't warn about converting any constant.  */
3106           && !TREE_CONSTANT (value))
3107         warning ("cast to pointer from integer of different size");
3108
3109       if (TREE_CODE (type) == POINTER_TYPE
3110           && TREE_CODE (otype) == POINTER_TYPE
3111           && TREE_CODE (expr) == ADDR_EXPR
3112           && DECL_P (TREE_OPERAND (expr, 0))
3113           && flag_strict_aliasing && warn_strict_aliasing
3114           && !VOID_TYPE_P (TREE_TYPE (type)))
3115         {
3116           /* Casting the address of a decl to non void pointer. Warn
3117              if the cast breaks type based aliasing.  */
3118           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3119             warning ("type-punning to incomplete type might break strict-aliasing rules");
3120           else
3121             {
3122               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3123               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3124
3125               if (!alias_sets_conflict_p (set1, set2))
3126                 warning ("dereferencing type-punned pointer will break strict-aliasing rules");
3127               else if (warn_strict_aliasing > 1
3128                        && !alias_sets_might_conflict_p (set1, set2))
3129                 warning ("dereferencing type-punned pointer might break strict-aliasing rules");
3130             }
3131         }
3132
3133       /* If pedantic, warn for conversions between function and object
3134          pointer types, except for converting a null pointer constant
3135          to function pointer type.  */
3136       if (pedantic
3137           && TREE_CODE (type) == POINTER_TYPE
3138           && TREE_CODE (otype) == POINTER_TYPE
3139           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3140           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3141         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3142
3143       if (pedantic
3144           && TREE_CODE (type) == POINTER_TYPE
3145           && TREE_CODE (otype) == POINTER_TYPE
3146           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3147           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3148           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3149                && TREE_CODE (expr) != NOP_EXPR))
3150         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3151
3152       ovalue = value;
3153       /* Replace a nonvolatile const static variable with its value.  */
3154       if (optimize && TREE_CODE (value) == VAR_DECL)
3155         value = decl_constant_value (value);
3156       value = convert (type, value);
3157
3158       /* Ignore any integer overflow caused by the cast.  */
3159       if (TREE_CODE (value) == INTEGER_CST)
3160         {
3161           TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3162
3163           if (TREE_CODE_CLASS (TREE_CODE (ovalue)) == 'c')
3164             TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3165         }
3166     }
3167
3168   /* Don't let (void *) (FOO *) 0 be a null pointer constant.  */
3169   if (TREE_CODE (value) == INTEGER_CST
3170       && TREE_CODE (expr) == INTEGER_CST
3171       && TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE)
3172     value = non_lvalue (value);
3173
3174   /* Don't let a cast be an lvalue.  */
3175   if (value == expr)
3176     value = non_lvalue (value);
3177
3178   return value;
3179 }
3180
3181 /* Interpret a cast of expression EXPR to type TYPE.  */
3182 tree
3183 c_cast_expr (tree type, tree expr)
3184 {
3185   int saved_wsp = warn_strict_prototypes;
3186
3187   /* This avoids warnings about unprototyped casts on
3188      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3189   if (TREE_CODE (expr) == INTEGER_CST)
3190     warn_strict_prototypes = 0;
3191   type = groktypename (type);
3192   warn_strict_prototypes = saved_wsp;
3193
3194   return build_c_cast (type, expr);
3195 }
3196
3197 \f
3198 /* Build an assignment expression of lvalue LHS from value RHS.
3199    MODIFYCODE is the code for a binary operator that we use
3200    to combine the old value of LHS with RHS to get the new value.
3201    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3202
3203 tree
3204 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3205 {
3206   tree result;
3207   tree newrhs;
3208   tree lhstype = TREE_TYPE (lhs);
3209   tree olhstype = lhstype;
3210
3211   /* Types that aren't fully specified cannot be used in assignments.  */
3212   lhs = require_complete_type (lhs);
3213
3214   /* Avoid duplicate error messages from operands that had errors.  */
3215   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3216     return error_mark_node;
3217
3218   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3219   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3220      whose value is 0 to count as a null pointer constant.  */
3221   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3222     rhs = TREE_OPERAND (rhs, 0);
3223
3224   newrhs = rhs;
3225
3226   /* If a binary op has been requested, combine the old LHS value with the RHS
3227      producing the value we should actually store into the LHS.  */
3228
3229   if (modifycode != NOP_EXPR)
3230     {
3231       lhs = stabilize_reference (lhs);
3232       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3233     }
3234
3235   if (!lvalue_or_else (lhs, "invalid lvalue in assignment"))
3236     return error_mark_node;
3237
3238   /* Warn about storing in something that is `const'.  */
3239
3240   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3241       || ((TREE_CODE (lhstype) == RECORD_TYPE
3242            || TREE_CODE (lhstype) == UNION_TYPE)
3243           && C_TYPE_FIELDS_READONLY (lhstype)))
3244     readonly_error (lhs, "assignment");
3245
3246   /* If storing into a structure or union member,
3247      it has probably been given type `int'.
3248      Compute the type that would go with
3249      the actual amount of storage the member occupies.  */
3250
3251   if (TREE_CODE (lhs) == COMPONENT_REF
3252       && (TREE_CODE (lhstype) == INTEGER_TYPE
3253           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3254           || TREE_CODE (lhstype) == REAL_TYPE
3255           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3256     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3257
3258   /* If storing in a field that is in actuality a short or narrower than one,
3259      we must store in the field in its actual type.  */
3260
3261   if (lhstype != TREE_TYPE (lhs))
3262     {
3263       lhs = copy_node (lhs);
3264       TREE_TYPE (lhs) = lhstype;
3265     }
3266
3267   /* Convert new value to destination type.  */
3268
3269   newrhs = convert_for_assignment (lhstype, newrhs, _("assignment"),
3270                                    NULL_TREE, NULL_TREE, 0);
3271   if (TREE_CODE (newrhs) == ERROR_MARK)
3272     return error_mark_node;
3273
3274   /* Scan operands */
3275
3276   result = build (MODIFY_EXPR, lhstype, lhs, newrhs);
3277   TREE_SIDE_EFFECTS (result) = 1;
3278
3279   /* If we got the LHS in a different type for storing in,
3280      convert the result back to the nominal type of LHS
3281      so that the value we return always has the same type
3282      as the LHS argument.  */
3283
3284   if (olhstype == TREE_TYPE (result))
3285     return result;
3286   return convert_for_assignment (olhstype, result, _("assignment"),
3287                                  NULL_TREE, NULL_TREE, 0);
3288 }
3289 \f
3290 /* Convert value RHS to type TYPE as preparation for an assignment
3291    to an lvalue of type TYPE.
3292    The real work of conversion is done by `convert'.
3293    The purpose of this function is to generate error messages
3294    for assignments that are not allowed in C.
3295    ERRTYPE is a string to use in error messages:
3296    "assignment", "return", etc.  If it is null, this is parameter passing
3297    for a function call (and different error messages are output).
3298
3299    FUNNAME is the name of the function being called,
3300    as an IDENTIFIER_NODE, or null.
3301    PARMNUM is the number of the argument, for printing in error messages.  */
3302
3303 static tree
3304 convert_for_assignment (tree type, tree rhs, const char *errtype,
3305                         tree fundecl, tree funname, int parmnum)
3306 {
3307   enum tree_code codel = TREE_CODE (type);
3308   tree rhstype;
3309   enum tree_code coder;
3310
3311   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3312   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3313      whose value is 0 to count as a null pointer constant.  */
3314   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
3315     rhs = TREE_OPERAND (rhs, 0);
3316
3317   if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
3318       || TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE)
3319     rhs = default_conversion (rhs);
3320   else if (optimize && TREE_CODE (rhs) == VAR_DECL)
3321     rhs = decl_constant_value_for_broken_optimization (rhs);
3322
3323   rhstype = TREE_TYPE (rhs);
3324   coder = TREE_CODE (rhstype);
3325
3326   if (coder == ERROR_MARK)
3327     return error_mark_node;
3328
3329   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3330     {
3331       overflow_warning (rhs);
3332       /* Check for Objective-C protocols.  This will automatically
3333          issue a warning if there are protocol violations.  No need to
3334          use the return value.  */
3335       if (c_dialect_objc ())
3336         objc_comptypes (type, rhstype, 0);
3337       return rhs;
3338     }
3339
3340   if (coder == VOID_TYPE)
3341     {
3342       error ("void value not ignored as it ought to be");
3343       return error_mark_node;
3344     }
3345   /* A type converts to a reference to it.
3346      This code doesn't fully support references, it's just for the
3347      special case of va_start and va_copy.  */
3348   if (codel == REFERENCE_TYPE
3349       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3350     {
3351       if (!lvalue_p (rhs))
3352         {
3353           error ("cannot pass rvalue to reference parameter");
3354           return error_mark_node;
3355         }
3356       if (!c_mark_addressable (rhs))
3357         return error_mark_node;
3358       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3359
3360       /* We already know that these two types are compatible, but they
3361          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3362          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3363          likely to be va_list, a typedef to __builtin_va_list, which
3364          is different enough that it will cause problems later.  */
3365       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3366         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3367
3368       rhs = build1 (NOP_EXPR, type, rhs);
3369       return rhs;
3370     }
3371   /* Some types can interconvert without explicit casts.  */
3372   else if (codel == VECTOR_TYPE
3373            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3374     return convert (type, rhs);
3375   /* Arithmetic types all interconvert, and enum is treated like int.  */
3376   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3377             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3378             || codel == BOOLEAN_TYPE)
3379            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3380                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3381                || coder == BOOLEAN_TYPE))
3382     return convert_and_check (type, rhs);
3383
3384   /* Conversion to a transparent union from its member types.
3385      This applies only to function arguments.  */
3386   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type) && ! errtype)
3387     {
3388       tree memb_types;
3389       tree marginal_memb_type = 0;
3390
3391       for (memb_types = TYPE_FIELDS (type); memb_types;
3392            memb_types = TREE_CHAIN (memb_types))
3393         {
3394           tree memb_type = TREE_TYPE (memb_types);
3395
3396           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3397                          TYPE_MAIN_VARIANT (rhstype)))
3398             break;
3399
3400           if (TREE_CODE (memb_type) != POINTER_TYPE)
3401             continue;
3402
3403           if (coder == POINTER_TYPE)
3404             {
3405               tree ttl = TREE_TYPE (memb_type);
3406               tree ttr = TREE_TYPE (rhstype);
3407
3408               /* Any non-function converts to a [const][volatile] void *
3409                  and vice versa; otherwise, targets must be the same.
3410                  Meanwhile, the lhs target must have all the qualifiers of
3411                  the rhs.  */
3412               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3413                   || comp_target_types (memb_type, rhstype, 0))
3414                 {
3415                   /* If this type won't generate any warnings, use it.  */
3416                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3417                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3418                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3419                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3420                              == TYPE_QUALS (ttr))
3421                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3422                              == TYPE_QUALS (ttl))))
3423                     break;
3424
3425                   /* Keep looking for a better type, but remember this one.  */
3426                   if (! marginal_memb_type)
3427                     marginal_memb_type = memb_type;
3428                 }
3429             }
3430
3431           /* Can convert integer zero to any pointer type.  */
3432           if (integer_zerop (rhs)
3433               || (TREE_CODE (rhs) == NOP_EXPR
3434                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3435             {
3436               rhs = null_pointer_node;
3437               break;
3438             }
3439         }
3440
3441       if (memb_types || marginal_memb_type)
3442         {
3443           if (! memb_types)
3444             {
3445               /* We have only a marginally acceptable member type;
3446                  it needs a warning.  */
3447               tree ttl = TREE_TYPE (marginal_memb_type);
3448               tree ttr = TREE_TYPE (rhstype);
3449
3450               /* Const and volatile mean something different for function
3451                  types, so the usual warnings are not appropriate.  */
3452               if (TREE_CODE (ttr) == FUNCTION_TYPE
3453                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3454                 {
3455                   /* Because const and volatile on functions are
3456                      restrictions that say the function will not do
3457                      certain things, it is okay to use a const or volatile
3458                      function where an ordinary one is wanted, but not
3459                      vice-versa.  */
3460                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3461                     warn_for_assignment ("%s makes qualified function pointer from unqualified",
3462                                          errtype, funname, parmnum);
3463                 }
3464               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3465                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3466                                      errtype, funname,
3467                                      parmnum);
3468             }
3469
3470           if (pedantic && ! DECL_IN_SYSTEM_HEADER (fundecl))
3471             pedwarn ("ISO C prohibits argument conversion to union type");
3472
3473           return build1 (NOP_EXPR, type, rhs);
3474         }
3475     }
3476
3477   /* Conversions among pointers */
3478   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3479            && (coder == codel))
3480     {
3481       tree ttl = TREE_TYPE (type);
3482       tree ttr = TREE_TYPE (rhstype);
3483       bool is_opaque_pointer;
3484       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3485
3486       /* Opaque pointers are treated like void pointers.  */
3487       is_opaque_pointer = (targetm.vector_opaque_p (type)
3488                            || targetm.vector_opaque_p (rhstype))
3489         && TREE_CODE (ttl) == VECTOR_TYPE
3490         && TREE_CODE (ttr) == VECTOR_TYPE;
3491
3492       /* Any non-function converts to a [const][volatile] void *
3493          and vice versa; otherwise, targets must be the same.
3494          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3495       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3496           || (target_cmp = comp_target_types (type, rhstype, 0))
3497           || is_opaque_pointer
3498           || (c_common_unsigned_type (TYPE_MAIN_VARIANT (ttl))
3499               == c_common_unsigned_type (TYPE_MAIN_VARIANT (ttr))))
3500         {
3501           if (pedantic
3502               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3503                   ||
3504                   (VOID_TYPE_P (ttr)
3505                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3506                       which are not ANSI null ptr constants.  */
3507                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3508                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3509             warn_for_assignment ("ISO C forbids %s between function pointer and `void *'",
3510                                  errtype, funname, parmnum);
3511           /* Const and volatile mean something different for function types,
3512              so the usual warnings are not appropriate.  */
3513           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3514                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3515             {
3516               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3517                 warn_for_assignment ("%s discards qualifiers from pointer target type",
3518                                      errtype, funname, parmnum);
3519               /* If this is not a case of ignoring a mismatch in signedness,
3520                  no warning.  */
3521               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3522                        || target_cmp)
3523                 ;
3524               /* If there is a mismatch, do warn.  */
3525               else if (pedantic)
3526                 warn_for_assignment ("pointer targets in %s differ in signedness",
3527                                      errtype, funname, parmnum);
3528             }
3529           else if (TREE_CODE (ttl) == FUNCTION_TYPE
3530                    && TREE_CODE (ttr) == FUNCTION_TYPE)
3531             {
3532               /* Because const and volatile on functions are restrictions
3533                  that say the function will not do certain things,
3534                  it is okay to use a const or volatile function
3535                  where an ordinary one is wanted, but not vice-versa.  */
3536               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3537                 warn_for_assignment ("%s makes qualified function pointer from unqualified",
3538                                      errtype, funname, parmnum);
3539             }
3540         }
3541       else
3542         warn_for_assignment ("%s from incompatible pointer type",
3543                              errtype, funname, parmnum);
3544       return convert (type, rhs);
3545     }
3546   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
3547     {
3548       error ("invalid use of non-lvalue array");
3549       return error_mark_node;
3550     }
3551   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
3552     {
3553       /* An explicit constant 0 can convert to a pointer,
3554          or one that results from arithmetic, even including
3555          a cast to integer type.  */
3556       if (! (TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
3557           &&
3558           ! (TREE_CODE (rhs) == NOP_EXPR
3559              && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
3560              && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
3561              && integer_zerop (TREE_OPERAND (rhs, 0))))
3562           warn_for_assignment ("%s makes pointer from integer without a cast",
3563                                errtype, funname, parmnum);
3564
3565       return convert (type, rhs);
3566     }
3567   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
3568     {
3569       warn_for_assignment ("%s makes integer from pointer without a cast",
3570                            errtype, funname, parmnum);
3571       return convert (type, rhs);
3572     }
3573   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
3574     return convert (type, rhs);
3575
3576   if (!errtype)
3577     {
3578       if (funname)
3579         {
3580           tree selector = objc_message_selector ();
3581
3582           if (selector && parmnum > 2)
3583             error ("incompatible type for argument %d of `%s'",
3584                    parmnum - 2, IDENTIFIER_POINTER (selector));
3585           else
3586             error ("incompatible type for argument %d of `%s'",
3587                    parmnum, IDENTIFIER_POINTER (funname));
3588         }
3589       else
3590         error ("incompatible type for argument %d of indirect function call",
3591                parmnum);
3592     }
3593   else
3594     error ("incompatible types in %s", errtype);
3595
3596   return error_mark_node;
3597 }
3598
3599 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
3600    is used for error and waring reporting and indicates which argument
3601    is being processed.  */
3602
3603 tree
3604 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
3605 {
3606   tree ret, type;
3607
3608   /* If FN was prototyped, the value has been converted already
3609      in convert_arguments.  */
3610   if (! value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
3611     return value;
3612
3613   type = TREE_TYPE (parm);
3614   ret = convert_for_assignment (type, value,
3615                                 (char *) 0 /* arg passing  */, fn,
3616                                 DECL_NAME (fn), argnum);
3617   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
3618       && INTEGRAL_TYPE_P (type)
3619       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3620     ret = default_conversion (ret);
3621   return ret;
3622 }
3623
3624 /* Print a warning using MSGID.
3625    It gets OPNAME as its one parameter.
3626    if OPNAME is null and ARGNUM is 0, it is replaced by "passing arg of `FUNCTION'".
3627    Otherwise if OPNAME is null, it is replaced by "passing arg ARGNUM of `FUNCTION'".
3628    FUNCTION and ARGNUM are handled specially if we are building an
3629    Objective-C selector.  */
3630
3631 static void
3632 warn_for_assignment (const char *msgid, const char *opname, tree function,
3633                      int argnum)
3634 {
3635   if (opname == 0)
3636     {
3637       tree selector = objc_message_selector ();
3638       char * new_opname;
3639
3640       if (selector && argnum > 2)
3641         {
3642           function = selector;
3643           argnum -= 2;
3644         }
3645       if (argnum == 0)
3646         {
3647           if (function)
3648             {
3649               /* Function name is known; supply it.  */
3650               const char *const argstring = _("passing arg of `%s'");
3651               new_opname = alloca (IDENTIFIER_LENGTH (function)
3652                                    + strlen (argstring) + 1 + 1);
3653               sprintf (new_opname, argstring,
3654                        IDENTIFIER_POINTER (function));
3655             }
3656           else
3657             {
3658               /* Function name unknown (call through ptr).  */
3659               const char *const argnofun = _("passing arg of pointer to function");
3660               new_opname = alloca (strlen (argnofun) + 1 + 1);
3661               sprintf (new_opname, argnofun);
3662             }
3663         }
3664       else if (function)
3665         {
3666           /* Function name is known; supply it.  */
3667           const char *const argstring = _("passing arg %d of `%s'");
3668           new_opname = alloca (IDENTIFIER_LENGTH (function)
3669                                + strlen (argstring) + 1 + 25 /*%d*/ + 1);
3670           sprintf (new_opname, argstring, argnum,
3671                    IDENTIFIER_POINTER (function));
3672         }
3673       else
3674         {
3675           /* Function name unknown (call through ptr); just give arg number.  */
3676           const char *const argnofun = _("passing arg %d of pointer to function");
3677           new_opname = alloca (strlen (argnofun) + 1 + 25 /*%d*/ + 1);
3678           sprintf (new_opname, argnofun, argnum);
3679         }
3680       opname = new_opname;
3681     }
3682   pedwarn (msgid, opname);
3683 }
3684 \f
3685 /* If VALUE is a compound expr all of whose expressions are constant, then
3686    return its value.  Otherwise, return error_mark_node.
3687
3688    This is for handling COMPOUND_EXPRs as initializer elements
3689    which is allowed with a warning when -pedantic is specified.  */
3690
3691 static tree
3692 valid_compound_expr_initializer (tree value, tree endtype)
3693 {
3694   if (TREE_CODE (value) == COMPOUND_EXPR)
3695     {
3696       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
3697           == error_mark_node)
3698         return error_mark_node;
3699       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
3700                                               endtype);
3701     }
3702   else if (! TREE_CONSTANT (value)
3703            && ! initializer_constant_valid_p (value, endtype))
3704     return error_mark_node;
3705   else
3706     return value;
3707 }
3708 \f
3709 /* Perform appropriate conversions on the initial value of a variable,
3710    store it in the declaration DECL,
3711    and print any error messages that are appropriate.
3712    If the init is invalid, store an ERROR_MARK.  */
3713
3714 void
3715 store_init_value (tree decl, tree init)
3716 {
3717   tree value, type;
3718
3719   /* If variable's type was invalidly declared, just ignore it.  */
3720
3721   type = TREE_TYPE (decl);
3722   if (TREE_CODE (type) == ERROR_MARK)
3723     return;
3724
3725   /* Digest the specified initializer into an expression.  */
3726
3727   value = digest_init (type, init, TREE_STATIC (decl));
3728
3729   /* Store the expression if valid; else report error.  */
3730
3731   if (warn_traditional && !in_system_header
3732       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && ! TREE_STATIC (decl))
3733     warning ("traditional C rejects automatic aggregate initialization");
3734
3735   DECL_INITIAL (decl) = value;
3736
3737   /* ANSI wants warnings about out-of-range constant initializers.  */
3738   STRIP_TYPE_NOPS (value);
3739   constant_expression_warning (value);
3740
3741   /* Check if we need to set array size from compound literal size.  */
3742   if (TREE_CODE (type) == ARRAY_TYPE
3743       && TYPE_DOMAIN (type) == 0
3744       && value != error_mark_node)
3745     {
3746       tree inside_init = init;
3747
3748       if (TREE_CODE (init) == NON_LVALUE_EXPR)
3749         inside_init = TREE_OPERAND (init, 0);
3750       inside_init = fold (inside_init);
3751
3752       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
3753         {
3754           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
3755
3756           if (TYPE_DOMAIN (TREE_TYPE (decl)))
3757             {
3758               /* For int foo[] = (int [3]){1}; we need to set array size
3759                  now since later on array initializer will be just the
3760                  brace enclosed list of the compound literal.  */
3761               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
3762               layout_type (type);
3763               layout_decl (decl, 0);
3764             }
3765         }
3766     }
3767 }
3768 \f
3769 /* Methods for storing and printing names for error messages.  */
3770
3771 /* Implement a spelling stack that allows components of a name to be pushed
3772    and popped.  Each element on the stack is this structure.  */
3773
3774 struct spelling
3775 {
3776   int kind;
3777   union
3778     {
3779       int i;
3780       const char *s;
3781     } u;
3782 };
3783
3784 #define SPELLING_STRING 1
3785 #define SPELLING_MEMBER 2
3786 #define SPELLING_BOUNDS 3
3787
3788 static struct spelling *spelling;       /* Next stack element (unused).  */
3789 static struct spelling *spelling_base;  /* Spelling stack base.  */
3790 static int spelling_size;               /* Size of the spelling stack.  */
3791
3792 /* Macros to save and restore the spelling stack around push_... functions.
3793    Alternative to SAVE_SPELLING_STACK.  */
3794
3795 #define SPELLING_DEPTH() (spelling - spelling_base)
3796 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
3797
3798 /* Push an element on the spelling stack with type KIND and assign VALUE
3799    to MEMBER.  */
3800
3801 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
3802 {                                                                       \
3803   int depth = SPELLING_DEPTH ();                                        \
3804                                                                         \
3805   if (depth >= spelling_size)                                           \
3806     {                                                                   \
3807       spelling_size += 10;                                              \
3808       if (spelling_base == 0)                                           \
3809         spelling_base = xmalloc (spelling_size * sizeof (struct spelling)); \
3810       else                                                              \
3811         spelling_base = xrealloc (spelling_base,                \
3812                                   spelling_size * sizeof (struct spelling)); \
3813       RESTORE_SPELLING_DEPTH (depth);                                   \
3814     }                                                                   \
3815                                                                         \
3816   spelling->kind = (KIND);                                              \
3817   spelling->MEMBER = (VALUE);                                           \
3818   spelling++;                                                           \
3819 }
3820
3821 /* Push STRING on the stack.  Printed literally.  */
3822
3823 static void
3824 push_string (const char *string)
3825 {
3826   PUSH_SPELLING (SPELLING_STRING, string, u.s);
3827 }
3828
3829 /* Push a member name on the stack.  Printed as '.' STRING.  */
3830
3831 static void
3832 push_member_name (tree decl)
3833 {
3834   const char *const string
3835     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
3836   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
3837 }
3838
3839 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
3840
3841 static void
3842 push_array_bounds (int bounds)
3843 {
3844   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
3845 }
3846
3847 /* Compute the maximum size in bytes of the printed spelling.  */
3848
3849 static int
3850 spelling_length (void)
3851 {
3852   int size = 0;
3853   struct spelling *p;
3854
3855   for (p = spelling_base; p < spelling; p++)
3856     {
3857       if (p->kind == SPELLING_BOUNDS)
3858         size += 25;
3859       else
3860         size += strlen (p->u.s) + 1;
3861     }
3862
3863   return size;
3864 }
3865
3866 /* Print the spelling to BUFFER and return it.  */
3867
3868 static char *
3869 print_spelling (char *buffer)
3870 {
3871   char *d = buffer;
3872   struct spelling *p;
3873
3874   for (p = spelling_base; p < spelling; p++)
3875     if (p->kind == SPELLING_BOUNDS)
3876       {
3877         sprintf (d, "[%d]", p->u.i);
3878         d += strlen (d);
3879       }
3880     else
3881       {
3882         const char *s;
3883         if (p->kind == SPELLING_MEMBER)
3884           *d++ = '.';
3885         for (s = p->u.s; (*d = *s++); d++)
3886           ;
3887       }
3888   *d++ = '\0';
3889   return buffer;
3890 }
3891
3892 /* Issue an error message for a bad initializer component.
3893    MSGID identifies the message.
3894    The component name is taken from the spelling stack.  */
3895
3896 void
3897 error_init (const char *msgid)
3898 {
3899   char *ofwhat;
3900
3901   error ("%s", _(msgid));
3902   ofwhat = print_spelling (alloca (spelling_length () + 1));
3903   if (*ofwhat)
3904     error ("(near initialization for `%s')", ofwhat);
3905 }
3906
3907 /* Issue a pedantic warning for a bad initializer component.
3908    MSGID identifies the message.
3909    The component name is taken from the spelling stack.  */
3910
3911 void
3912 pedwarn_init (const char *msgid)
3913 {
3914   char *ofwhat;
3915
3916   pedwarn ("%s", _(msgid));
3917   ofwhat = print_spelling (alloca (spelling_length () + 1));
3918   if (*ofwhat)
3919     pedwarn ("(near initialization for `%s')", ofwhat);
3920 }
3921
3922 /* Issue a warning for a bad initializer component.
3923    MSGID identifies the message.
3924    The component name is taken from the spelling stack.  */
3925
3926 static void
3927 warning_init (const char *msgid)
3928 {
3929   char *ofwhat;
3930
3931   warning ("%s", _(msgid));
3932   ofwhat = print_spelling (alloca (spelling_length () + 1));
3933   if (*ofwhat)
3934     warning ("(near initialization for `%s')", ofwhat);
3935 }
3936 \f
3937 /* Digest the parser output INIT as an initializer for type TYPE.
3938    Return a C expression of type TYPE to represent the initial value.
3939
3940    REQUIRE_CONSTANT requests an error if non-constant initializers or
3941    elements are seen.  */
3942
3943 static tree
3944 digest_init (tree type, tree init, int require_constant)
3945 {
3946   enum tree_code code = TREE_CODE (type);
3947   tree inside_init = init;
3948
3949   if (type == error_mark_node
3950       || init == error_mark_node
3951       || TREE_TYPE (init) == error_mark_node)
3952     return error_mark_node;
3953
3954   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
3955   /* Do not use STRIP_NOPS here.  We do not want an enumerator
3956      whose value is 0 to count as a null pointer constant.  */
3957   if (TREE_CODE (init) == NON_LVALUE_EXPR)
3958     inside_init = TREE_OPERAND (init, 0);
3959
3960   inside_init = fold (inside_init);
3961
3962   /* Initialization of an array of chars from a string constant
3963      optionally enclosed in braces.  */
3964
3965   if (code == ARRAY_TYPE)
3966     {
3967       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
3968       if ((typ1 == char_type_node
3969            || typ1 == signed_char_type_node
3970            || typ1 == unsigned_char_type_node
3971            || typ1 == unsigned_wchar_type_node
3972            || typ1 == signed_wchar_type_node)
3973           && ((inside_init && TREE_CODE (inside_init) == STRING_CST)))
3974         {
3975           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
3976                          TYPE_MAIN_VARIANT (type)))
3977             return inside_init;
3978
3979           if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3980                != char_type_node)
3981               && TYPE_PRECISION (typ1) == TYPE_PRECISION (char_type_node))
3982             {
3983               error_init ("char-array initialized from wide string");
3984               return error_mark_node;
3985             }
3986           if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
3987                == char_type_node)
3988               && TYPE_PRECISION (typ1) != TYPE_PRECISION (char_type_node))
3989             {
3990               error_init ("int-array initialized from non-wide string");
3991               return error_mark_node;
3992             }
3993
3994           TREE_TYPE (inside_init) = type;
3995           if (TYPE_DOMAIN (type) != 0
3996               && TYPE_SIZE (type) != 0
3997               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
3998               /* Subtract 1 (or sizeof (wchar_t))
3999                  because it's ok to ignore the terminating null char
4000                  that is counted in the length of the constant.  */
4001               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4002                                        TREE_STRING_LENGTH (inside_init)
4003                                        - ((TYPE_PRECISION (typ1)
4004                                            != TYPE_PRECISION (char_type_node))
4005                                           ? (TYPE_PRECISION (wchar_type_node)
4006                                              / BITS_PER_UNIT)
4007                                           : 1)))
4008             pedwarn_init ("initializer-string for array of chars is too long");
4009
4010           return inside_init;
4011         }
4012     }
4013
4014   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4015      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4016      below and handle as a constructor.  */
4017     if (code == VECTOR_TYPE
4018         && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4019         && TREE_CONSTANT (inside_init))
4020       {
4021         if (TREE_CODE (inside_init) == VECTOR_CST
4022             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4023                           TYPE_MAIN_VARIANT (type)))
4024           return inside_init;
4025         else
4026           return build_vector (type, CONSTRUCTOR_ELTS (inside_init));
4027       }
4028
4029   /* Any type can be initialized
4030      from an expression of the same type, optionally with braces.  */
4031
4032   if (inside_init && TREE_TYPE (inside_init) != 0
4033       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4034                      TYPE_MAIN_VARIANT (type))
4035           || (code == ARRAY_TYPE
4036               && comptypes (TREE_TYPE (inside_init), type))
4037           || (code == VECTOR_TYPE
4038               && comptypes (TREE_TYPE (inside_init), type))
4039           || (code == POINTER_TYPE
4040               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4041               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4042                             TREE_TYPE (type)))
4043           || (code == POINTER_TYPE
4044               && TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE
4045               && comptypes (TREE_TYPE (inside_init),
4046                             TREE_TYPE (type)))))
4047     {
4048       if (code == POINTER_TYPE)
4049         {
4050           inside_init = default_function_array_conversion (inside_init);
4051
4052           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4053             {
4054               error_init ("invalid use of non-lvalue array");
4055               return error_mark_node;
4056             }
4057          }
4058
4059       if (code == VECTOR_TYPE)
4060         /* Although the types are compatible, we may require a
4061            conversion.  */
4062         inside_init = convert (type, inside_init);
4063
4064       if (require_constant && !flag_isoc99
4065           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4066         {
4067           /* As an extension, allow initializing objects with static storage
4068              duration with compound literals (which are then treated just as
4069              the brace enclosed list they contain).  */
4070           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4071           inside_init = DECL_INITIAL (decl);
4072         }
4073
4074       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4075           && TREE_CODE (inside_init) != CONSTRUCTOR)
4076         {
4077           error_init ("array initialized from non-constant array expression");
4078           return error_mark_node;
4079         }
4080
4081       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4082         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4083
4084       /* Compound expressions can only occur here if -pedantic or
4085          -pedantic-errors is specified.  In the later case, we always want
4086          an error.  In the former case, we simply want a warning.  */
4087       if (require_constant && pedantic
4088           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4089         {
4090           inside_init
4091             = valid_compound_expr_initializer (inside_init,
4092                                                TREE_TYPE (inside_init));
4093           if (inside_init == error_mark_node)
4094             error_init ("initializer element is not constant");
4095           else
4096             pedwarn_init ("initializer element is not constant");
4097           if (flag_pedantic_errors)
4098             inside_init = error_mark_node;
4099         }
4100       else if (require_constant
4101                && (!TREE_CONSTANT (inside_init)
4102                    /* This test catches things like `7 / 0' which
4103                       result in an expression for which TREE_CONSTANT
4104                       is true, but which is not actually something
4105                       that is a legal constant.  We really should not
4106                       be using this function, because it is a part of
4107                       the back-end.  Instead, the expression should
4108                       already have been turned into ERROR_MARK_NODE.  */
4109                    || !initializer_constant_valid_p (inside_init,
4110                                                      TREE_TYPE (inside_init))))
4111         {
4112           error_init ("initializer element is not constant");
4113           inside_init = error_mark_node;
4114         }
4115
4116       return inside_init;
4117     }
4118
4119   /* Handle scalar types, including conversions.  */
4120
4121   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4122       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4123       || code == VECTOR_TYPE)
4124     {
4125       /* Note that convert_for_assignment calls default_conversion
4126          for arrays and functions.  We must not call it in the
4127          case where inside_init is a null pointer constant.  */
4128       inside_init
4129         = convert_for_assignment (type, init, _("initialization"),
4130                                   NULL_TREE, NULL_TREE, 0);
4131
4132       if (require_constant && ! TREE_CONSTANT (inside_init))
4133         {
4134           error_init ("initializer element is not constant");
4135           inside_init = error_mark_node;
4136         }
4137       else if (require_constant
4138                && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
4139         {
4140           error_init ("initializer element is not computable at load time");
4141           inside_init = error_mark_node;
4142         }
4143
4144       return inside_init;
4145     }
4146
4147   /* Come here only for records and arrays.  */
4148
4149   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4150     {
4151       error_init ("variable-sized object may not be initialized");
4152       return error_mark_node;
4153     }
4154
4155   error_init ("invalid initializer");
4156   return error_mark_node;
4157 }
4158 \f
4159 /* Handle initializers that use braces.  */
4160
4161 /* Type of object we are accumulating a constructor for.
4162    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4163 static tree constructor_type;
4164
4165 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4166    left to fill.  */
4167 static tree constructor_fields;
4168
4169 /* For an ARRAY_TYPE, this is the specified index
4170    at which to store the next element we get.  */
4171 static tree constructor_index;
4172
4173 /* For an ARRAY_TYPE, this is the maximum index.  */
4174 static tree constructor_max_index;
4175
4176 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4177 static tree constructor_unfilled_fields;
4178
4179 /* For an ARRAY_TYPE, this is the index of the first element
4180    not yet written out.  */
4181 static tree constructor_unfilled_index;
4182
4183 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4184    This is so we can generate gaps between fields, when appropriate.  */
4185 static tree constructor_bit_index;
4186
4187 /* If we are saving up the elements rather than allocating them,
4188    this is the list of elements so far (in reverse order,
4189    most recent first).  */
4190 static tree constructor_elements;
4191
4192 /* 1 if constructor should be incrementally stored into a constructor chain,
4193    0 if all the elements should be kept in AVL tree.  */
4194 static int constructor_incremental;
4195
4196 /* 1 if so far this constructor's elements are all compile-time constants.  */
4197 static int constructor_constant;
4198
4199 /* 1 if so far this constructor's elements are all valid address constants.  */
4200 static int constructor_simple;
4201
4202 /* 1 if this constructor is erroneous so far.  */
4203 static int constructor_erroneous;
4204
4205 /* Structure for managing pending initializer elements, organized as an
4206    AVL tree.  */
4207
4208 struct init_node
4209 {
4210   struct init_node *left, *right;
4211   struct init_node *parent;
4212   int balance;
4213   tree purpose;
4214   tree value;
4215 };
4216
4217 /* Tree of pending elements at this constructor level.
4218    These are elements encountered out of order
4219    which belong at places we haven't reached yet in actually
4220    writing the output.
4221    Will never hold tree nodes across GC runs.  */
4222 static struct init_node *constructor_pending_elts;
4223
4224 /* The SPELLING_DEPTH of this constructor.  */
4225 static int constructor_depth;
4226
4227 /* 0 if implicitly pushing constructor levels is allowed.  */
4228 int constructor_no_implicit = 0; /* 0 for C; 1 for some other languages.  */
4229
4230 /* DECL node for which an initializer is being read.
4231    0 means we are reading a constructor expression
4232    such as (struct foo) {...}.  */
4233 static tree constructor_decl;
4234
4235 /* start_init saves the ASMSPEC arg here for really_start_incremental_init.  */
4236 static const char *constructor_asmspec;
4237
4238 /* Nonzero if this is an initializer for a top-level decl.  */
4239 static int constructor_top_level;
4240
4241 /* Nonzero if there were any member designators in this initializer.  */
4242 static int constructor_designated;
4243
4244 /* Nesting depth of designator list.  */
4245 static int designator_depth;
4246
4247 /* Nonzero if there were diagnosed errors in this designator list.  */
4248 static int designator_errorneous;
4249
4250 \f
4251 /* This stack has a level for each implicit or explicit level of
4252    structuring in the initializer, including the outermost one.  It
4253    saves the values of most of the variables above.  */
4254
4255 struct constructor_range_stack;
4256
4257 struct constructor_stack
4258 {
4259   struct constructor_stack *next;
4260   tree type;
4261   tree fields;
4262   tree index;
4263   tree max_index;
4264   tree unfilled_index;
4265   tree unfilled_fields;
4266   tree bit_index;
4267   tree elements;
4268   struct init_node *pending_elts;
4269   int offset;
4270   int depth;
4271   /* If nonzero, this value should replace the entire
4272      constructor at this level.  */
4273   tree replacement_value;
4274   struct constructor_range_stack *range_stack;
4275   char constant;
4276   char simple;
4277   char implicit;
4278   char erroneous;
4279   char outer;
4280   char incremental;
4281   char designated;
4282 };
4283
4284 struct constructor_stack *constructor_stack;
4285
4286 /* This stack represents designators from some range designator up to
4287    the last designator in the list.  */
4288
4289 struct constructor_range_stack
4290 {
4291   struct constructor_range_stack *next, *prev;
4292   struct constructor_stack *stack;
4293   tree range_start;
4294   tree index;
4295   tree range_end;
4296   tree fields;
4297 };
4298
4299 struct constructor_range_stack *constructor_range_stack;
4300
4301 /* This stack records separate initializers that are nested.
4302    Nested initializers can't happen in ANSI C, but GNU C allows them
4303    in cases like { ... (struct foo) { ... } ... }.  */
4304
4305 struct initializer_stack
4306 {
4307   struct initializer_stack *next;
4308   tree decl;
4309   const char *asmspec;
4310   struct constructor_stack *constructor_stack;
4311   struct constructor_range_stack *constructor_range_stack;
4312   tree elements;
4313   struct spelling *spelling;
4314   struct spelling *spelling_base;
4315   int spelling_size;
4316   char top_level;
4317   char require_constant_value;
4318   char require_constant_elements;
4319 };
4320
4321 struct initializer_stack *initializer_stack;
4322 \f
4323 /* Prepare to parse and output the initializer for variable DECL.  */
4324
4325 void
4326 start_init (tree decl, tree asmspec_tree, int top_level)
4327 {
4328   const char *locus;
4329   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4330   const char *asmspec = 0;
4331
4332   if (asmspec_tree)
4333     asmspec = TREE_STRING_POINTER (asmspec_tree);
4334
4335   p->decl = constructor_decl;
4336   p->asmspec = constructor_asmspec;
4337   p->require_constant_value = require_constant_value;
4338   p->require_constant_elements = require_constant_elements;
4339   p->constructor_stack = constructor_stack;
4340   p->constructor_range_stack = constructor_range_stack;
4341   p->elements = constructor_elements;
4342   p->spelling = spelling;
4343   p->spelling_base = spelling_base;
4344   p->spelling_size = spelling_size;
4345   p->top_level = constructor_top_level;
4346   p->next = initializer_stack;
4347   initializer_stack = p;
4348
4349   constructor_decl = decl;
4350   constructor_asmspec = asmspec;
4351   constructor_designated = 0;
4352   constructor_top_level = top_level;
4353
4354   if (decl != 0)
4355     {
4356       require_constant_value = TREE_STATIC (decl);
4357       require_constant_elements
4358         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4359            /* For a scalar, you can always use any value to initialize,
4360               even within braces.  */
4361            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4362                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4363                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4364                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4365       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4366     }
4367   else
4368     {
4369       require_constant_value = 0;
4370       require_constant_elements = 0;
4371       locus = "(anonymous)";
4372     }
4373
4374   constructor_stack = 0;
4375   constructor_range_stack = 0;
4376
4377   missing_braces_mentioned = 0;
4378
4379   spelling_base = 0;
4380   spelling_size = 0;
4381   RESTORE_SPELLING_DEPTH (0);
4382
4383   if (locus)
4384     push_string (locus);
4385 }
4386
4387 void
4388 finish_init (void)
4389 {
4390   struct initializer_stack *p = initializer_stack;
4391
4392   /* Free the whole constructor stack of this initializer.  */
4393   while (constructor_stack)
4394     {
4395       struct constructor_stack *q = constructor_stack;
4396       constructor_stack = q->next;
4397       free (q);
4398     }
4399
4400   if (constructor_range_stack)
4401     abort ();
4402
4403   /* Pop back to the data of the outer initializer (if any).  */
4404   free (spelling_base);
4405
4406   constructor_decl = p->decl;
4407   constructor_asmspec = p->asmspec;
4408   require_constant_value = p->require_constant_value;
4409   require_constant_elements = p->require_constant_elements;
4410   constructor_stack = p->constructor_stack;
4411   constructor_range_stack = p->constructor_range_stack;
4412   constructor_elements = p->elements;
4413   spelling = p->spelling;
4414   spelling_base = p->spelling_base;
4415   spelling_size = p->spelling_size;
4416   constructor_top_level = p->top_level;
4417   initializer_stack = p->next;
4418   free (p);
4419 }
4420 \f
4421 /* Call here when we see the initializer is surrounded by braces.
4422    This is instead of a call to push_init_level;
4423    it is matched by a call to pop_init_level.
4424
4425    TYPE is the type to initialize, for a constructor expression.
4426    For an initializer for a decl, TYPE is zero.  */
4427
4428 void
4429 really_start_incremental_init (tree type)
4430 {
4431   struct constructor_stack *p = xmalloc (sizeof (struct constructor_stack));
4432
4433   if (type == 0)
4434     type = TREE_TYPE (constructor_decl);
4435
4436   if (targetm.vector_opaque_p (type))
4437     error ("opaque vector types cannot be initialized");
4438
4439   p->type = constructor_type;
4440   p->fields = constructor_fields;
4441   p->index = constructor_index;
4442   p->max_index = constructor_max_index;
4443   p->unfilled_index = constructor_unfilled_index;
4444   p->unfilled_fields = constructor_unfilled_fields;
4445   p->bit_index = constructor_bit_index;
4446   p->elements = constructor_elements;
4447   p->constant = constructor_constant;
4448   p->simple = constructor_simple;
4449   p->erroneous = constructor_erroneous;
4450   p->pending_elts = constructor_pending_elts;
4451   p->depth = constructor_depth;
4452   p->replacement_value = 0;
4453   p->implicit = 0;
4454   p->range_stack = 0;
4455   p->outer = 0;
4456   p->incremental = constructor_incremental;
4457   p->designated = constructor_designated;
4458   p->next = 0;
4459   constructor_stack = p;
4460
4461   constructor_constant = 1;
4462   constructor_simple = 1;
4463   constructor_depth = SPELLING_DEPTH ();
4464   constructor_elements = 0;
4465   constructor_pending_elts = 0;
4466   constructor_type = type;
4467   constructor_incremental = 1;
4468   constructor_designated = 0;
4469   designator_depth = 0;
4470   designator_errorneous = 0;
4471
4472   if (TREE_CODE (constructor_type) == RECORD_TYPE
4473       || TREE_CODE (constructor_type) == UNION_TYPE)
4474     {
4475       constructor_fields = TYPE_FIELDS (constructor_type);
4476       /* Skip any nameless bit fields at the beginning.  */
4477       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4478              && DECL_NAME (constructor_fields) == 0)
4479         constructor_fields = TREE_CHAIN (constructor_fields);
4480
4481       constructor_unfilled_fields = constructor_fields;
4482       constructor_bit_index = bitsize_zero_node;
4483     }
4484   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4485     {
4486       if (TYPE_DOMAIN (constructor_type))
4487         {
4488           constructor_max_index
4489             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4490
4491           /* Detect non-empty initializations of zero-length arrays.  */
4492           if (constructor_max_index == NULL_TREE
4493               && TYPE_SIZE (constructor_type))
4494             constructor_max_index = build_int_2 (-1, -1);
4495
4496           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4497              to initialize VLAs will cause a proper error; avoid tree
4498              checking errors as well by setting a safe value.  */
4499           if (constructor_max_index
4500               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4501             constructor_max_index = build_int_2 (-1, -1);
4502
4503           constructor_index
4504             = convert (bitsizetype,
4505                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4506         }
4507       else
4508         constructor_index = bitsize_zero_node;
4509
4510       constructor_unfilled_index = constructor_index;
4511     }
4512   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4513     {
4514       /* Vectors are like simple fixed-size arrays.  */
4515       constructor_max_index =
4516         build_int_2 (TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4517       constructor_index = convert (bitsizetype, bitsize_zero_node);
4518       constructor_unfilled_index = constructor_index;
4519     }
4520   else
4521     {
4522       /* Handle the case of int x = {5}; */
4523       constructor_fields = constructor_type;
4524       constructor_unfilled_fields = constructor_type;
4525     }
4526 }
4527 \f
4528 /* Push down into a subobject, for initialization.
4529    If this is for an explicit set of braces, IMPLICIT is 0.
4530    If it is because the next element belongs at a lower level,
4531    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
4532
4533 void
4534 push_init_level (int implicit)
4535 {
4536   struct constructor_stack *p;
4537   tree value = NULL_TREE;
4538
4539   /* If we've exhausted any levels that didn't have braces,
4540      pop them now.  */
4541   while (constructor_stack->implicit)
4542     {
4543       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4544            || TREE_CODE (constructor_type) == UNION_TYPE)
4545           && constructor_fields == 0)
4546         process_init_element (pop_init_level (1));
4547       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
4548                && constructor_max_index
4549                && tree_int_cst_lt (constructor_max_index, constructor_index))
4550         process_init_element (pop_init_level (1));
4551       else
4552         break;
4553     }
4554
4555   /* Unless this is an explicit brace, we need to preserve previous
4556      content if any.  */
4557   if (implicit)
4558     {
4559       if ((TREE_CODE (constructor_type) == RECORD_TYPE
4560            || TREE_CODE (constructor_type) == UNION_TYPE)
4561           && constructor_fields)
4562         value = find_init_member (constructor_fields);
4563       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4564         value = find_init_member (constructor_index);
4565     }
4566
4567   p = xmalloc (sizeof (struct constructor_stack));
4568   p->type = constructor_type;
4569   p->fields = constructor_fields;
4570   p->index = constructor_index;
4571   p->max_index = constructor_max_index;
4572   p->unfilled_index = constructor_unfilled_index;
4573   p->unfilled_fields = constructor_unfilled_fields;
4574   p->bit_index = constructor_bit_index;
4575   p->elements = constructor_elements;
4576   p->constant = constructor_constant;
4577   p->simple = constructor_simple;
4578   p->erroneous = constructor_erroneous;
4579   p->pending_elts = constructor_pending_elts;
4580   p->depth = constructor_depth;
4581   p->replacement_value = 0;
4582   p->implicit = implicit;
4583   p->outer = 0;
4584   p->incremental = constructor_incremental;
4585   p->designated = constructor_designated;
4586   p->next = constructor_stack;
4587   p->range_stack = 0;
4588   constructor_stack = p;
4589
4590   constructor_constant = 1;
4591   constructor_simple = 1;
4592   constructor_depth = SPELLING_DEPTH ();
4593   constructor_elements = 0;
4594   constructor_incremental = 1;
4595   constructor_designated = 0;
4596   constructor_pending_elts = 0;
4597   if (!implicit)
4598     {
4599       p->range_stack = constructor_range_stack;
4600       constructor_range_stack = 0;
4601       designator_depth = 0;
4602       designator_errorneous = 0;
4603     }
4604
4605   /* Don't die if an entire brace-pair level is superfluous
4606      in the containing level.  */
4607   if (constructor_type == 0)
4608     ;
4609   else if (TREE_CODE (constructor_type) == RECORD_TYPE
4610            || TREE_CODE (constructor_type) == UNION_TYPE)
4611     {
4612       /* Don't die if there are extra init elts at the end.  */
4613       if (constructor_fields == 0)
4614         constructor_type = 0;
4615       else
4616         {
4617           constructor_type = TREE_TYPE (constructor_fields);
4618           push_member_name (constructor_fields);
4619           constructor_depth++;
4620         }
4621     }
4622   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4623     {
4624       constructor_type = TREE_TYPE (constructor_type);
4625       push_array_bounds (tree_low_cst (constructor_index, 0));
4626       constructor_depth++;
4627     }
4628
4629   if (constructor_type == 0)
4630     {
4631       error_init ("extra brace group at end of initializer");
4632       constructor_fields = 0;
4633       constructor_unfilled_fields = 0;
4634       return;
4635     }
4636
4637   if (value && TREE_CODE (value) == CONSTRUCTOR)
4638     {
4639       constructor_constant = TREE_CONSTANT (value);
4640       constructor_simple = TREE_STATIC (value);
4641       constructor_elements = CONSTRUCTOR_ELTS (value);
4642       if (constructor_elements
4643           && (TREE_CODE (constructor_type) == RECORD_TYPE
4644               || TREE_CODE (constructor_type) == ARRAY_TYPE))
4645         set_nonincremental_init ();
4646     }
4647
4648   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
4649     {
4650       missing_braces_mentioned = 1;
4651       warning_init ("missing braces around initializer");
4652     }
4653
4654   if (TREE_CODE (constructor_type) == RECORD_TYPE
4655            || TREE_CODE (constructor_type) == UNION_TYPE)
4656     {
4657       constructor_fields = TYPE_FIELDS (constructor_type);
4658       /* Skip any nameless bit fields at the beginning.  */
4659       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4660              && DECL_NAME (constructor_fields) == 0)
4661         constructor_fields = TREE_CHAIN (constructor_fields);
4662
4663       constructor_unfilled_fields = constructor_fields;
4664       constructor_bit_index = bitsize_zero_node;
4665     }
4666   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4667     {
4668       /* Vectors are like simple fixed-size arrays.  */
4669       constructor_max_index =
4670         build_int_2 (TYPE_VECTOR_SUBPARTS (constructor_type) - 1, 0);
4671       constructor_index = convert (bitsizetype, integer_zero_node);
4672       constructor_unfilled_index = constructor_index;
4673     }
4674   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4675     {
4676       if (TYPE_DOMAIN (constructor_type))
4677         {
4678           constructor_max_index
4679             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4680
4681           /* Detect non-empty initializations of zero-length arrays.  */
4682           if (constructor_max_index == NULL_TREE
4683               && TYPE_SIZE (constructor_type))
4684             constructor_max_index = build_int_2 (-1, -1);
4685
4686           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4687              to initialize VLAs will cause a proper error; avoid tree
4688              checking errors as well by setting a safe value.  */
4689           if (constructor_max_index
4690               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4691             constructor_max_index = build_int_2 (-1, -1);
4692
4693           constructor_index
4694             = convert (bitsizetype,
4695                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4696         }
4697       else
4698         constructor_index = bitsize_zero_node;
4699
4700       constructor_unfilled_index = constructor_index;
4701       if (value && TREE_CODE (value) == STRING_CST)
4702         {
4703           /* We need to split the char/wchar array into individual
4704              characters, so that we don't have to special case it
4705              everywhere.  */
4706           set_nonincremental_init_from_string (value);
4707         }
4708     }
4709   else
4710     {
4711       warning_init ("braces around scalar initializer");
4712       constructor_fields = constructor_type;
4713       constructor_unfilled_fields = constructor_type;
4714     }
4715 }
4716
4717 /* At the end of an implicit or explicit brace level,
4718    finish up that level of constructor.
4719    If we were outputting the elements as they are read, return 0
4720    from inner levels (process_init_element ignores that),
4721    but return error_mark_node from the outermost level
4722    (that's what we want to put in DECL_INITIAL).
4723    Otherwise, return a CONSTRUCTOR expression.  */
4724
4725 tree
4726 pop_init_level (int implicit)
4727 {
4728   struct constructor_stack *p;
4729   tree constructor = 0;
4730
4731   if (implicit == 0)
4732     {
4733       /* When we come to an explicit close brace,
4734          pop any inner levels that didn't have explicit braces.  */
4735       while (constructor_stack->implicit)
4736         process_init_element (pop_init_level (1));
4737
4738       if (constructor_range_stack)
4739         abort ();
4740     }
4741
4742   /* Now output all pending elements.  */
4743   constructor_incremental = 1;
4744   output_pending_init_elements (1);
4745
4746   p = constructor_stack;
4747
4748   /* Error for initializing a flexible array member, or a zero-length
4749      array member in an inappropriate context.  */
4750   if (constructor_type && constructor_fields
4751       && TREE_CODE (constructor_type) == ARRAY_TYPE
4752       && TYPE_DOMAIN (constructor_type)
4753       && ! TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
4754     {
4755       /* Silently discard empty initializations.  The parser will
4756          already have pedwarned for empty brackets.  */
4757       if (integer_zerop (constructor_unfilled_index))
4758         constructor_type = NULL_TREE;
4759       else if (! TYPE_SIZE (constructor_type))
4760         {
4761           if (constructor_depth > 2)
4762             error_init ("initialization of flexible array member in a nested context");
4763           else if (pedantic)
4764             pedwarn_init ("initialization of a flexible array member");
4765
4766           /* We have already issued an error message for the existence
4767              of a flexible array member not at the end of the structure.
4768              Discard the initializer so that we do not abort later.  */
4769           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
4770             constructor_type = NULL_TREE;
4771         }
4772       else
4773         /* Zero-length arrays are no longer special, so we should no longer
4774            get here.  */
4775         abort ();
4776     }
4777
4778   /* Warn when some struct elements are implicitly initialized to zero.  */
4779   if (extra_warnings
4780       && constructor_type
4781       && TREE_CODE (constructor_type) == RECORD_TYPE
4782       && constructor_unfilled_fields)
4783     {
4784         /* Do not warn for flexible array members or zero-length arrays.  */
4785         while (constructor_unfilled_fields
4786                && (! DECL_SIZE (constructor_unfilled_fields)
4787                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
4788           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
4789
4790         /* Do not warn if this level of the initializer uses member
4791            designators; it is likely to be deliberate.  */
4792         if (constructor_unfilled_fields && !constructor_designated)
4793           {
4794             push_member_name (constructor_unfilled_fields);
4795             warning_init ("missing initializer");
4796             RESTORE_SPELLING_DEPTH (constructor_depth);
4797           }
4798     }
4799
4800   /* Pad out the end of the structure.  */
4801   if (p->replacement_value)
4802     /* If this closes a superfluous brace pair,
4803        just pass out the element between them.  */
4804     constructor = p->replacement_value;
4805   else if (constructor_type == 0)
4806     ;
4807   else if (TREE_CODE (constructor_type) != RECORD_TYPE
4808            && TREE_CODE (constructor_type) != UNION_TYPE
4809            && TREE_CODE (constructor_type) != ARRAY_TYPE
4810            && TREE_CODE (constructor_type) != VECTOR_TYPE)
4811     {
4812       /* A nonincremental scalar initializer--just return
4813          the element, after verifying there is just one.  */
4814       if (constructor_elements == 0)
4815         {
4816           if (!constructor_erroneous)
4817             error_init ("empty scalar initializer");
4818           constructor = error_mark_node;
4819         }
4820       else if (TREE_CHAIN (constructor_elements) != 0)
4821         {
4822           error_init ("extra elements in scalar initializer");
4823           constructor = TREE_VALUE (constructor_elements);
4824         }
4825       else
4826         constructor = TREE_VALUE (constructor_elements);
4827     }
4828   else
4829     {
4830       if (constructor_erroneous)
4831         constructor = error_mark_node;
4832       else
4833         {
4834           constructor = build_constructor (constructor_type,
4835                                            nreverse (constructor_elements));
4836           if (constructor_constant)
4837             TREE_CONSTANT (constructor) = TREE_INVARIANT (constructor) = 1;
4838           if (constructor_constant && constructor_simple)
4839             TREE_STATIC (constructor) = 1;
4840         }
4841     }
4842
4843   constructor_type = p->type;
4844   constructor_fields = p->fields;
4845   constructor_index = p->index;
4846   constructor_max_index = p->max_index;
4847   constructor_unfilled_index = p->unfilled_index;
4848   constructor_unfilled_fields = p->unfilled_fields;
4849   constructor_bit_index = p->bit_index;
4850   constructor_elements = p->elements;
4851   constructor_constant = p->constant;
4852   constructor_simple = p->simple;
4853   constructor_erroneous = p->erroneous;
4854   constructor_incremental = p->incremental;
4855   constructor_designated = p->designated;
4856   constructor_pending_elts = p->pending_elts;
4857   constructor_depth = p->depth;
4858   if (!p->implicit)
4859     constructor_range_stack = p->range_stack;
4860   RESTORE_SPELLING_DEPTH (constructor_depth);
4861
4862   constructor_stack = p->next;
4863   free (p);
4864
4865   if (constructor == 0)
4866     {
4867       if (constructor_stack == 0)
4868         return error_mark_node;
4869       return NULL_TREE;
4870     }
4871   return constructor;
4872 }
4873
4874 /* Common handling for both array range and field name designators.
4875    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
4876
4877 static int
4878 set_designator (int array)
4879 {
4880   tree subtype;
4881   enum tree_code subcode;
4882
4883   /* Don't die if an entire brace-pair level is superfluous
4884      in the containing level.  */
4885   if (constructor_type == 0)
4886     return 1;
4887
4888   /* If there were errors in this designator list already, bail out silently.  */
4889   if (designator_errorneous)
4890     return 1;
4891
4892   if (!designator_depth)
4893     {
4894       if (constructor_range_stack)
4895         abort ();
4896
4897       /* Designator list starts at the level of closest explicit
4898          braces.  */
4899       while (constructor_stack->implicit)
4900         process_init_element (pop_init_level (1));
4901       constructor_designated = 1;
4902       return 0;
4903     }
4904
4905   if (constructor_no_implicit)
4906     {
4907       error_init ("initialization designators may not nest");
4908       return 1;
4909     }
4910
4911   if (TREE_CODE (constructor_type) == RECORD_TYPE
4912       || TREE_CODE (constructor_type) == UNION_TYPE)
4913     {
4914       subtype = TREE_TYPE (constructor_fields);
4915       if (subtype != error_mark_node)
4916         subtype = TYPE_MAIN_VARIANT (subtype);
4917     }
4918   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4919     {
4920       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
4921     }
4922   else
4923     abort ();
4924
4925   subcode = TREE_CODE (subtype);
4926   if (array && subcode != ARRAY_TYPE)
4927     {
4928       error_init ("array index in non-array initializer");
4929       return 1;
4930     }
4931   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
4932     {
4933       error_init ("field name not in record or union initializer");
4934       return 1;
4935     }
4936
4937   constructor_designated = 1;
4938   push_init_level (2);
4939   return 0;
4940 }
4941
4942 /* If there are range designators in designator list, push a new designator
4943    to constructor_range_stack.  RANGE_END is end of such stack range or
4944    NULL_TREE if there is no range designator at this level.  */
4945
4946 static void
4947 push_range_stack (tree range_end)
4948 {
4949   struct constructor_range_stack *p;
4950
4951   p = ggc_alloc (sizeof (struct constructor_range_stack));
4952   p->prev = constructor_range_stack;
4953   p->next = 0;
4954   p->fields = constructor_fields;
4955   p->range_start = constructor_index;
4956   p->index = constructor_index;
4957   p->stack = constructor_stack;
4958   p->range_end = range_end;
4959   if (constructor_range_stack)
4960     constructor_range_stack->next = p;
4961   constructor_range_stack = p;
4962 }
4963
4964 /* Within an array initializer, specify the next index to be initialized.
4965    FIRST is that index.  If LAST is nonzero, then initialize a range
4966    of indices, running from FIRST through LAST.  */
4967
4968 void
4969 set_init_index (tree first, tree last)
4970 {
4971   if (set_designator (1))
4972     return;
4973
4974   designator_errorneous = 1;
4975
4976   while ((TREE_CODE (first) == NOP_EXPR
4977           || TREE_CODE (first) == CONVERT_EXPR
4978           || TREE_CODE (first) == NON_LVALUE_EXPR)
4979          && (TYPE_MODE (TREE_TYPE (first))
4980              == TYPE_MODE (TREE_TYPE (TREE_OPERAND (first, 0)))))
4981     first = TREE_OPERAND (first, 0);
4982
4983   if (last)
4984     while ((TREE_CODE (last) == NOP_EXPR
4985             || TREE_CODE (last) == CONVERT_EXPR
4986             || TREE_CODE (last) == NON_LVALUE_EXPR)
4987            && (TYPE_MODE (TREE_TYPE (last))
4988                == TYPE_MODE (TREE_TYPE (TREE_OPERAND (last, 0)))))
4989       last = TREE_OPERAND (last, 0);
4990
4991   if (TREE_CODE (first) != INTEGER_CST)
4992     error_init ("nonconstant array index in initializer");
4993   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
4994     error_init ("nonconstant array index in initializer");
4995   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
4996     error_init ("array index in non-array initializer");
4997   else if (tree_int_cst_sgn (first) == -1)
4998     error_init ("array index in initializer exceeds array bounds");
4999   else if (constructor_max_index
5000            && tree_int_cst_lt (constructor_max_index, first))
5001     error_init ("array index in initializer exceeds array bounds");
5002   else
5003     {
5004       constructor_index = convert (bitsizetype, first);
5005
5006       if (last)
5007         {
5008           if (tree_int_cst_equal (first, last))
5009             last = 0;
5010           else if (tree_int_cst_lt (last, first))
5011             {
5012               error_init ("empty index range in initializer");
5013               last = 0;
5014             }
5015           else
5016             {
5017               last = convert (bitsizetype, last);
5018               if (constructor_max_index != 0
5019                   && tree_int_cst_lt (constructor_max_index, last))
5020                 {
5021                   error_init ("array index range in initializer exceeds array bounds");
5022                   last = 0;
5023                 }
5024             }
5025         }
5026
5027       designator_depth++;
5028       designator_errorneous = 0;
5029       if (constructor_range_stack || last)
5030         push_range_stack (last);
5031     }
5032 }
5033
5034 /* Within a struct initializer, specify the next field to be initialized.  */
5035
5036 void
5037 set_init_label (tree fieldname)
5038 {
5039   tree tail;
5040
5041   if (set_designator (0))
5042     return;
5043
5044   designator_errorneous = 1;
5045
5046   if (TREE_CODE (constructor_type) != RECORD_TYPE
5047       && TREE_CODE (constructor_type) != UNION_TYPE)
5048     {
5049       error_init ("field name not in record or union initializer");
5050       return;
5051     }
5052
5053   for (tail = TYPE_FIELDS (constructor_type); tail;
5054        tail = TREE_CHAIN (tail))
5055     {
5056       if (DECL_NAME (tail) == fieldname)
5057         break;
5058     }
5059
5060   if (tail == 0)
5061     error ("unknown field `%s' specified in initializer",
5062            IDENTIFIER_POINTER (fieldname));
5063   else
5064     {
5065       constructor_fields = tail;
5066       designator_depth++;
5067       designator_errorneous = 0;
5068       if (constructor_range_stack)
5069         push_range_stack (NULL_TREE);
5070     }
5071 }
5072 \f
5073 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5074    identifies the initializer, either array index or field in a structure.
5075    VALUE is the value of that index or field.  */
5076
5077 static void
5078 add_pending_init (tree purpose, tree value)
5079 {
5080   struct init_node *p, **q, *r;
5081
5082   q = &constructor_pending_elts;
5083   p = 0;
5084
5085   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5086     {
5087       while (*q != 0)
5088         {
5089           p = *q;
5090           if (tree_int_cst_lt (purpose, p->purpose))
5091             q = &p->left;
5092           else if (tree_int_cst_lt (p->purpose, purpose))
5093             q = &p->right;
5094           else
5095             {
5096               if (TREE_SIDE_EFFECTS (p->value))
5097                 warning_init ("initialized field with side-effects overwritten");
5098               p->value = value;
5099               return;
5100             }
5101         }
5102     }
5103   else
5104     {
5105       tree bitpos;
5106
5107       bitpos = bit_position (purpose);
5108       while (*q != NULL)
5109         {
5110           p = *q;
5111           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5112             q = &p->left;
5113           else if (p->purpose != purpose)
5114             q = &p->right;
5115           else
5116             {
5117               if (TREE_SIDE_EFFECTS (p->value))
5118                 warning_init ("initialized field with side-effects overwritten");
5119               p->value = value;
5120               return;
5121             }
5122         }
5123     }
5124
5125   r = ggc_alloc (sizeof (struct init_node));
5126   r->purpose = purpose;
5127   r->value = value;
5128
5129   *q = r;
5130   r->parent = p;
5131   r->left = 0;
5132   r->right = 0;
5133   r->balance = 0;
5134
5135   while (p)
5136     {
5137       struct init_node *s;
5138
5139       if (r == p->left)
5140         {
5141           if (p->balance == 0)
5142             p->balance = -1;
5143           else if (p->balance < 0)
5144             {
5145               if (r->balance < 0)
5146                 {
5147                   /* L rotation.  */
5148                   p->left = r->right;
5149                   if (p->left)
5150                     p->left->parent = p;
5151                   r->right = p;
5152
5153                   p->balance = 0;
5154                   r->balance = 0;
5155
5156                   s = p->parent;
5157                   p->parent = r;
5158                   r->parent = s;
5159                   if (s)
5160                     {
5161                       if (s->left == p)
5162                         s->left = r;
5163                       else
5164                         s->right = r;
5165                     }
5166                   else
5167                     constructor_pending_elts = r;
5168                 }
5169               else
5170                 {
5171                   /* LR rotation.  */
5172                   struct init_node *t = r->right;
5173
5174                   r->right = t->left;
5175                   if (r->right)
5176                     r->right->parent = r;
5177                   t->left = r;
5178
5179                   p->left = t->right;
5180                   if (p->left)
5181                     p->left->parent = p;
5182                   t->right = p;
5183
5184                   p->balance = t->balance < 0;
5185                   r->balance = -(t->balance > 0);
5186                   t->balance = 0;
5187
5188                   s = p->parent;
5189                   p->parent = t;
5190                   r->parent = t;
5191                   t->parent = s;
5192                   if (s)
5193                     {
5194                       if (s->left == p)
5195                         s->left = t;
5196                       else
5197                         s->right = t;
5198                     }
5199                   else
5200                     constructor_pending_elts = t;
5201                 }
5202               break;
5203             }
5204           else
5205             {
5206               /* p->balance == +1; growth of left side balances the node.  */
5207               p->balance = 0;
5208               break;
5209             }
5210         }
5211       else /* r == p->right */
5212         {
5213           if (p->balance == 0)
5214             /* Growth propagation from right side.  */
5215             p->balance++;
5216           else if (p->balance > 0)
5217             {
5218               if (r->balance > 0)
5219                 {
5220                   /* R rotation.  */
5221                   p->right = r->left;
5222                   if (p->right)
5223                     p->right->parent = p;
5224                   r->left = p;
5225
5226                   p->balance = 0;
5227                   r->balance = 0;
5228
5229                   s = p->parent;
5230                   p->parent = r;
5231                   r->parent = s;
5232                   if (s)
5233                     {
5234                       if (s->left == p)
5235                         s->left = r;
5236                       else
5237                         s->right = r;
5238                     }
5239                   else
5240                     constructor_pending_elts = r;
5241                 }
5242               else /* r->balance == -1 */
5243                 {
5244                   /* RL rotation */
5245                   struct init_node *t = r->left;
5246
5247                   r->left = t->right;
5248                   if (r->left)
5249                     r->left->parent = r;
5250                   t->right = r;
5251
5252                   p->right = t->left;
5253                   if (p->right)
5254                     p->right->parent = p;
5255                   t->left = p;
5256
5257                   r->balance = (t->balance < 0);
5258                   p->balance = -(t->balance > 0);
5259                   t->balance = 0;
5260
5261                   s = p->parent;
5262                   p->parent = t;
5263                   r->parent = t;
5264                   t->parent = s;
5265                   if (s)
5266                     {
5267                       if (s->left == p)
5268                         s->left = t;
5269                       else
5270                         s->right = t;
5271                     }
5272                   else
5273                     constructor_pending_elts = t;
5274                 }
5275               break;
5276             }
5277           else
5278             {
5279               /* p->balance == -1; growth of right side balances the node.  */
5280               p->balance = 0;
5281               break;
5282             }
5283         }
5284
5285       r = p;
5286       p = p->parent;
5287     }
5288 }
5289
5290 /* Build AVL tree from a sorted chain.  */
5291
5292 static void
5293 set_nonincremental_init (void)
5294 {
5295   tree chain;
5296
5297   if (TREE_CODE (constructor_type) != RECORD_TYPE
5298       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5299     return;
5300
5301   for (chain = constructor_elements; chain; chain = TREE_CHAIN (chain))
5302     add_pending_init (TREE_PURPOSE (chain), TREE_VALUE (chain));
5303   constructor_elements = 0;
5304   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5305     {
5306       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5307       /* Skip any nameless bit fields at the beginning.  */
5308       while (constructor_unfilled_fields != 0
5309              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5310              && DECL_NAME (constructor_unfilled_fields) == 0)
5311         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5312
5313     }
5314   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5315     {
5316       if (TYPE_DOMAIN (constructor_type))
5317         constructor_unfilled_index
5318             = convert (bitsizetype,
5319                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5320       else
5321         constructor_unfilled_index = bitsize_zero_node;
5322     }
5323   constructor_incremental = 0;
5324 }
5325
5326 /* Build AVL tree from a string constant.  */
5327
5328 static void
5329 set_nonincremental_init_from_string (tree str)
5330 {
5331   tree value, purpose, type;
5332   HOST_WIDE_INT val[2];
5333   const char *p, *end;
5334   int byte, wchar_bytes, charwidth, bitpos;
5335
5336   if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5337     abort ();
5338
5339   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5340       == TYPE_PRECISION (char_type_node))
5341     wchar_bytes = 1;
5342   else if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5343            == TYPE_PRECISION (wchar_type_node))
5344     wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5345   else
5346     abort ();
5347
5348   charwidth = TYPE_PRECISION (char_type_node);
5349   type = TREE_TYPE (constructor_type);
5350   p = TREE_STRING_POINTER (str);
5351   end = p + TREE_STRING_LENGTH (str);
5352
5353   for (purpose = bitsize_zero_node;
5354        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5355        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5356     {
5357       if (wchar_bytes == 1)
5358         {
5359           val[1] = (unsigned char) *p++;
5360           val[0] = 0;
5361         }
5362       else
5363         {
5364           val[0] = 0;
5365           val[1] = 0;
5366           for (byte = 0; byte < wchar_bytes; byte++)
5367             {
5368               if (BYTES_BIG_ENDIAN)
5369                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5370               else
5371                 bitpos = byte * charwidth;
5372               val[bitpos < HOST_BITS_PER_WIDE_INT]
5373                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5374                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5375             }
5376         }
5377
5378       if (!TYPE_UNSIGNED (type))
5379         {
5380           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5381           if (bitpos < HOST_BITS_PER_WIDE_INT)
5382             {
5383               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5384                 {
5385                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5386                   val[0] = -1;
5387                 }
5388             }
5389           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5390             {
5391               if (val[1] < 0)
5392                 val[0] = -1;
5393             }
5394           else if (val[0] & (((HOST_WIDE_INT) 1)
5395                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5396             val[0] |= ((HOST_WIDE_INT) -1)
5397                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5398         }
5399
5400       value = build_int_2 (val[1], val[0]);
5401       TREE_TYPE (value) = type;
5402       add_pending_init (purpose, value);
5403     }
5404
5405   constructor_incremental = 0;
5406 }
5407
5408 /* Return value of FIELD in pending initializer or zero if the field was
5409    not initialized yet.  */
5410
5411 static tree
5412 find_init_member (tree field)
5413 {
5414   struct init_node *p;
5415
5416   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5417     {
5418       if (constructor_incremental
5419           && tree_int_cst_lt (field, constructor_unfilled_index))
5420         set_nonincremental_init ();
5421
5422       p = constructor_pending_elts;
5423       while (p)
5424         {
5425           if (tree_int_cst_lt (field, p->purpose))
5426             p = p->left;
5427           else if (tree_int_cst_lt (p->purpose, field))
5428             p = p->right;
5429           else
5430             return p->value;
5431         }
5432     }
5433   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5434     {
5435       tree bitpos = bit_position (field);
5436
5437       if (constructor_incremental
5438           && (!constructor_unfilled_fields
5439               || tree_int_cst_lt (bitpos,
5440                                   bit_position (constructor_unfilled_fields))))
5441         set_nonincremental_init ();
5442
5443       p = constructor_pending_elts;
5444       while (p)
5445         {
5446           if (field == p->purpose)
5447             return p->value;
5448           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5449             p = p->left;
5450           else
5451             p = p->right;
5452         }
5453     }
5454   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5455     {
5456       if (constructor_elements
5457           && TREE_PURPOSE (constructor_elements) == field)
5458         return TREE_VALUE (constructor_elements);
5459     }
5460   return 0;
5461 }
5462
5463 /* "Output" the next constructor element.
5464    At top level, really output it to assembler code now.
5465    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5466    TYPE is the data type that the containing data type wants here.
5467    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5468
5469    PENDING if non-nil means output pending elements that belong
5470    right after this element.  (PENDING is normally 1;
5471    it is 0 while outputting pending elements, to avoid recursion.)  */
5472
5473 static void
5474 output_init_element (tree value, tree type, tree field, int pending)
5475 {
5476   if (type == error_mark_node)
5477     {
5478       constructor_erroneous = 1;
5479       return;
5480     }
5481   if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
5482       || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5483           && !(TREE_CODE (value) == STRING_CST
5484                && TREE_CODE (type) == ARRAY_TYPE
5485                && TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE)
5486           && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5487                          TYPE_MAIN_VARIANT (type))))
5488     value = default_conversion (value);
5489
5490   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5491       && require_constant_value && !flag_isoc99 && pending)
5492     {
5493       /* As an extension, allow initializing objects with static storage
5494          duration with compound literals (which are then treated just as
5495          the brace enclosed list they contain).  */
5496       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5497       value = DECL_INITIAL (decl);
5498     }
5499
5500   if (value == error_mark_node)
5501     constructor_erroneous = 1;
5502   else if (!TREE_CONSTANT (value))
5503     constructor_constant = 0;
5504   else if (initializer_constant_valid_p (value, TREE_TYPE (value)) == 0
5505            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5506                 || TREE_CODE (constructor_type) == UNION_TYPE)
5507                && DECL_C_BIT_FIELD (field)
5508                && TREE_CODE (value) != INTEGER_CST))
5509     constructor_simple = 0;
5510
5511   if (require_constant_value && ! TREE_CONSTANT (value))
5512     {
5513       error_init ("initializer element is not constant");
5514       value = error_mark_node;
5515     }
5516   else if (require_constant_elements
5517            && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
5518     pedwarn ("initializer element is not computable at load time");
5519
5520   /* If this field is empty (and not at the end of structure),
5521      don't do anything other than checking the initializer.  */
5522   if (field
5523       && (TREE_TYPE (field) == error_mark_node
5524           || (COMPLETE_TYPE_P (TREE_TYPE (field))
5525               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
5526               && (TREE_CODE (constructor_type) == ARRAY_TYPE
5527                   || TREE_CHAIN (field)))))
5528     return;
5529
5530   value = digest_init (type, value, require_constant_value);
5531   if (value == error_mark_node)
5532     {
5533       constructor_erroneous = 1;
5534       return;
5535     }
5536
5537   /* If this element doesn't come next in sequence,
5538      put it on constructor_pending_elts.  */
5539   if (TREE_CODE (constructor_type) == ARRAY_TYPE
5540       && (!constructor_incremental
5541           || !tree_int_cst_equal (field, constructor_unfilled_index)))
5542     {
5543       if (constructor_incremental
5544           && tree_int_cst_lt (field, constructor_unfilled_index))
5545         set_nonincremental_init ();
5546
5547       add_pending_init (field, value);
5548       return;
5549     }
5550   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5551            && (!constructor_incremental
5552                || field != constructor_unfilled_fields))
5553     {
5554       /* We do this for records but not for unions.  In a union,
5555          no matter which field is specified, it can be initialized
5556          right away since it starts at the beginning of the union.  */
5557       if (constructor_incremental)
5558         {
5559           if (!constructor_unfilled_fields)
5560             set_nonincremental_init ();
5561           else
5562             {
5563               tree bitpos, unfillpos;
5564
5565               bitpos = bit_position (field);
5566               unfillpos = bit_position (constructor_unfilled_fields);
5567
5568               if (tree_int_cst_lt (bitpos, unfillpos))
5569                 set_nonincremental_init ();
5570             }
5571         }
5572
5573       add_pending_init (field, value);
5574       return;
5575     }
5576   else if (TREE_CODE (constructor_type) == UNION_TYPE
5577            && constructor_elements)
5578     {
5579       if (TREE_SIDE_EFFECTS (TREE_VALUE (constructor_elements)))
5580         warning_init ("initialized field with side-effects overwritten");
5581
5582       /* We can have just one union field set.  */
5583       constructor_elements = 0;
5584     }
5585
5586   /* Otherwise, output this element either to
5587      constructor_elements or to the assembler file.  */
5588
5589   if (field && TREE_CODE (field) == INTEGER_CST)
5590     field = copy_node (field);
5591   constructor_elements
5592     = tree_cons (field, value, constructor_elements);
5593
5594   /* Advance the variable that indicates sequential elements output.  */
5595   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5596     constructor_unfilled_index
5597       = size_binop (PLUS_EXPR, constructor_unfilled_index,
5598                     bitsize_one_node);
5599   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5600     {
5601       constructor_unfilled_fields
5602         = TREE_CHAIN (constructor_unfilled_fields);
5603
5604       /* Skip any nameless bit fields.  */
5605       while (constructor_unfilled_fields != 0
5606              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5607              && DECL_NAME (constructor_unfilled_fields) == 0)
5608         constructor_unfilled_fields =
5609           TREE_CHAIN (constructor_unfilled_fields);
5610     }
5611   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5612     constructor_unfilled_fields = 0;
5613
5614   /* Now output any pending elements which have become next.  */
5615   if (pending)
5616     output_pending_init_elements (0);
5617 }
5618
5619 /* Output any pending elements which have become next.
5620    As we output elements, constructor_unfilled_{fields,index}
5621    advances, which may cause other elements to become next;
5622    if so, they too are output.
5623
5624    If ALL is 0, we return when there are
5625    no more pending elements to output now.
5626
5627    If ALL is 1, we output space as necessary so that
5628    we can output all the pending elements.  */
5629
5630 static void
5631 output_pending_init_elements (int all)
5632 {
5633   struct init_node *elt = constructor_pending_elts;
5634   tree next;
5635
5636  retry:
5637
5638   /* Look through the whole pending tree.
5639      If we find an element that should be output now,
5640      output it.  Otherwise, set NEXT to the element
5641      that comes first among those still pending.  */
5642
5643   next = 0;
5644   while (elt)
5645     {
5646       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5647         {
5648           if (tree_int_cst_equal (elt->purpose,
5649                                   constructor_unfilled_index))
5650             output_init_element (elt->value,
5651                                  TREE_TYPE (constructor_type),
5652                                  constructor_unfilled_index, 0);
5653           else if (tree_int_cst_lt (constructor_unfilled_index,
5654                                     elt->purpose))
5655             {
5656               /* Advance to the next smaller node.  */
5657               if (elt->left)
5658                 elt = elt->left;
5659               else
5660                 {
5661                   /* We have reached the smallest node bigger than the
5662                      current unfilled index.  Fill the space first.  */
5663                   next = elt->purpose;
5664                   break;
5665                 }
5666             }
5667           else
5668             {
5669               /* Advance to the next bigger node.  */
5670               if (elt->right)
5671                 elt = elt->right;
5672               else
5673                 {
5674                   /* We have reached the biggest node in a subtree.  Find
5675                      the parent of it, which is the next bigger node.  */
5676                   while (elt->parent && elt->parent->right == elt)
5677                     elt = elt->parent;
5678                   elt = elt->parent;
5679                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
5680                                               elt->purpose))
5681                     {
5682                       next = elt->purpose;
5683                       break;
5684                     }
5685                 }
5686             }
5687         }
5688       else if (TREE_CODE (constructor_type) == RECORD_TYPE
5689                || TREE_CODE (constructor_type) == UNION_TYPE)
5690         {
5691           tree ctor_unfilled_bitpos, elt_bitpos;
5692
5693           /* If the current record is complete we are done.  */
5694           if (constructor_unfilled_fields == 0)
5695             break;
5696
5697           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
5698           elt_bitpos = bit_position (elt->purpose);
5699           /* We can't compare fields here because there might be empty
5700              fields in between.  */
5701           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
5702             {
5703               constructor_unfilled_fields = elt->purpose;
5704               output_init_element (elt->value, TREE_TYPE (elt->purpose),
5705                                    elt->purpose, 0);
5706             }
5707           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
5708             {
5709               /* Advance to the next smaller node.  */
5710               if (elt->left)
5711                 elt = elt->left;
5712               else
5713                 {
5714                   /* We have reached the smallest node bigger than the
5715                      current unfilled field.  Fill the space first.  */
5716                   next = elt->purpose;
5717                   break;
5718                 }
5719             }
5720           else
5721             {
5722               /* Advance to the next bigger node.  */
5723               if (elt->right)
5724                 elt = elt->right;
5725               else
5726                 {
5727                   /* We have reached the biggest node in a subtree.  Find
5728                      the parent of it, which is the next bigger node.  */
5729                   while (elt->parent && elt->parent->right == elt)
5730                     elt = elt->parent;
5731                   elt = elt->parent;
5732                   if (elt
5733                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
5734                                            bit_position (elt->purpose))))
5735                     {
5736                       next = elt->purpose;
5737                       break;
5738                     }
5739                 }
5740             }
5741         }
5742     }
5743
5744   /* Ordinarily return, but not if we want to output all
5745      and there are elements left.  */
5746   if (! (all && next != 0))
5747     return;
5748
5749   /* If it's not incremental, just skip over the gap, so that after
5750      jumping to retry we will output the next successive element.  */
5751   if (TREE_CODE (constructor_type) == RECORD_TYPE
5752       || TREE_CODE (constructor_type) == UNION_TYPE)
5753     constructor_unfilled_fields = next;
5754   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5755     constructor_unfilled_index = next;
5756
5757   /* ELT now points to the node in the pending tree with the next
5758      initializer to output.  */
5759   goto retry;
5760 }
5761 \f
5762 /* Add one non-braced element to the current constructor level.
5763    This adjusts the current position within the constructor's type.
5764    This may also start or terminate implicit levels
5765    to handle a partly-braced initializer.
5766
5767    Once this has found the correct level for the new element,
5768    it calls output_init_element.  */
5769
5770 void
5771 process_init_element (tree value)
5772 {
5773   tree orig_value = value;
5774   int string_flag = value != 0 && TREE_CODE (value) == STRING_CST;
5775
5776   designator_depth = 0;
5777   designator_errorneous = 0;
5778
5779   /* Handle superfluous braces around string cst as in
5780      char x[] = {"foo"}; */
5781   if (string_flag
5782       && constructor_type
5783       && TREE_CODE (constructor_type) == ARRAY_TYPE
5784       && TREE_CODE (TREE_TYPE (constructor_type)) == INTEGER_TYPE
5785       && integer_zerop (constructor_unfilled_index))
5786     {
5787       if (constructor_stack->replacement_value)
5788         error_init ("excess elements in char array initializer");
5789       constructor_stack->replacement_value = value;
5790       return;
5791     }
5792
5793   if (constructor_stack->replacement_value != 0)
5794     {
5795       error_init ("excess elements in struct initializer");
5796       return;
5797     }
5798
5799   /* Ignore elements of a brace group if it is entirely superfluous
5800      and has already been diagnosed.  */
5801   if (constructor_type == 0)
5802     return;
5803
5804   /* If we've exhausted any levels that didn't have braces,
5805      pop them now.  */
5806   while (constructor_stack->implicit)
5807     {
5808       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5809            || TREE_CODE (constructor_type) == UNION_TYPE)
5810           && constructor_fields == 0)
5811         process_init_element (pop_init_level (1));
5812       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5813                && (constructor_max_index == 0
5814                    || tree_int_cst_lt (constructor_max_index,
5815                                        constructor_index)))
5816         process_init_element (pop_init_level (1));
5817       else
5818         break;
5819     }
5820
5821   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
5822   if (constructor_range_stack)
5823     {
5824       /* If value is a compound literal and we'll be just using its
5825          content, don't put it into a SAVE_EXPR.  */
5826       if (TREE_CODE (value) != COMPOUND_LITERAL_EXPR
5827           || !require_constant_value
5828           || flag_isoc99)
5829         value = save_expr (value);
5830     }
5831
5832   while (1)
5833     {
5834       if (TREE_CODE (constructor_type) == RECORD_TYPE)
5835         {
5836           tree fieldtype;
5837           enum tree_code fieldcode;
5838
5839           if (constructor_fields == 0)
5840             {
5841               pedwarn_init ("excess elements in struct initializer");
5842               break;
5843             }
5844
5845           fieldtype = TREE_TYPE (constructor_fields);
5846           if (fieldtype != error_mark_node)
5847             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5848           fieldcode = TREE_CODE (fieldtype);
5849
5850           /* Error for non-static initialization of a flexible array member.  */
5851           if (fieldcode == ARRAY_TYPE
5852               && !require_constant_value
5853               && TYPE_SIZE (fieldtype) == NULL_TREE
5854               && TREE_CHAIN (constructor_fields) == NULL_TREE)
5855             {
5856               error_init ("non-static initialization of a flexible array member");
5857               break;
5858             }
5859
5860           /* Accept a string constant to initialize a subarray.  */
5861           if (value != 0
5862               && fieldcode == ARRAY_TYPE
5863               && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
5864               && string_flag)
5865             value = orig_value;
5866           /* Otherwise, if we have come to a subaggregate,
5867              and we don't have an element of its type, push into it.  */
5868           else if (value != 0 && !constructor_no_implicit
5869                    && value != error_mark_node
5870                    && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != fieldtype
5871                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5872                        || fieldcode == UNION_TYPE))
5873             {
5874               push_init_level (1);
5875               continue;
5876             }
5877
5878           if (value)
5879             {
5880               push_member_name (constructor_fields);
5881               output_init_element (value, fieldtype, constructor_fields, 1);
5882               RESTORE_SPELLING_DEPTH (constructor_depth);
5883             }
5884           else
5885             /* Do the bookkeeping for an element that was
5886                directly output as a constructor.  */
5887             {
5888               /* For a record, keep track of end position of last field.  */
5889               if (DECL_SIZE (constructor_fields))
5890                 constructor_bit_index
5891                   = size_binop (PLUS_EXPR,
5892                                 bit_position (constructor_fields),
5893                                 DECL_SIZE (constructor_fields));
5894
5895               /* If the current field was the first one not yet written out,
5896                  it isn't now, so update.  */
5897               if (constructor_unfilled_fields == constructor_fields)
5898                 {
5899                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5900                   /* Skip any nameless bit fields.  */
5901                   while (constructor_unfilled_fields != 0
5902                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5903                          && DECL_NAME (constructor_unfilled_fields) == 0)
5904                     constructor_unfilled_fields =
5905                       TREE_CHAIN (constructor_unfilled_fields);
5906                 }
5907             }
5908
5909           constructor_fields = TREE_CHAIN (constructor_fields);
5910           /* Skip any nameless bit fields at the beginning.  */
5911           while (constructor_fields != 0
5912                  && DECL_C_BIT_FIELD (constructor_fields)
5913                  && DECL_NAME (constructor_fields) == 0)
5914             constructor_fields = TREE_CHAIN (constructor_fields);
5915         }
5916       else if (TREE_CODE (constructor_type) == UNION_TYPE)
5917         {
5918           tree fieldtype;
5919           enum tree_code fieldcode;
5920
5921           if (constructor_fields == 0)
5922             {
5923               pedwarn_init ("excess elements in union initializer");
5924               break;
5925             }
5926
5927           fieldtype = TREE_TYPE (constructor_fields);
5928           if (fieldtype != error_mark_node)
5929             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
5930           fieldcode = TREE_CODE (fieldtype);
5931
5932           /* Warn that traditional C rejects initialization of unions.
5933              We skip the warning if the value is zero.  This is done
5934              under the assumption that the zero initializer in user
5935              code appears conditioned on e.g. __STDC__ to avoid
5936              "missing initializer" warnings and relies on default
5937              initialization to zero in the traditional C case.
5938              We also skip the warning if the initializer is designated,
5939              again on the assumption that this must be conditional on
5940              __STDC__ anyway (and we've already complained about the
5941              member-designator already).  */
5942           if (warn_traditional && !in_system_header && !constructor_designated
5943               && !(value && (integer_zerop (value) || real_zerop (value))))
5944             warning ("traditional C rejects initialization of unions");
5945
5946           /* Accept a string constant to initialize a subarray.  */
5947           if (value != 0
5948               && fieldcode == ARRAY_TYPE
5949               && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
5950               && string_flag)
5951             value = orig_value;
5952           /* Otherwise, if we have come to a subaggregate,
5953              and we don't have an element of its type, push into it.  */
5954           else if (value != 0 && !constructor_no_implicit
5955                    && value != error_mark_node
5956                    && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != fieldtype
5957                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
5958                        || fieldcode == UNION_TYPE))
5959             {
5960               push_init_level (1);
5961               continue;
5962             }
5963
5964           if (value)
5965             {
5966               push_member_name (constructor_fields);
5967               output_init_element (value, fieldtype, constructor_fields, 1);
5968               RESTORE_SPELLING_DEPTH (constructor_depth);
5969             }
5970           else
5971             /* Do the bookkeeping for an element that was
5972                directly output as a constructor.  */
5973             {
5974               constructor_bit_index = DECL_SIZE (constructor_fields);
5975               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
5976             }
5977
5978           constructor_fields = 0;
5979         }
5980       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5981         {
5982           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5983           enum tree_code eltcode = TREE_CODE (elttype);
5984
5985           /* Accept a string constant to initialize a subarray.  */
5986           if (value != 0
5987               && eltcode == ARRAY_TYPE
5988               && TREE_CODE (TREE_TYPE (elttype)) == INTEGER_TYPE
5989               && string_flag)
5990             value = orig_value;
5991           /* Otherwise, if we have come to a subaggregate,
5992              and we don't have an element of its type, push into it.  */
5993           else if (value != 0 && !constructor_no_implicit
5994                    && value != error_mark_node
5995                    && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != elttype
5996                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
5997                        || eltcode == UNION_TYPE))
5998             {
5999               push_init_level (1);
6000               continue;
6001             }
6002
6003           if (constructor_max_index != 0
6004               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6005                   || integer_all_onesp (constructor_max_index)))
6006             {
6007               pedwarn_init ("excess elements in array initializer");
6008               break;
6009             }
6010
6011           /* Now output the actual element.  */
6012           if (value)
6013             {
6014               push_array_bounds (tree_low_cst (constructor_index, 0));
6015               output_init_element (value, elttype, constructor_index, 1);
6016               RESTORE_SPELLING_DEPTH (constructor_depth);
6017             }
6018
6019           constructor_index
6020             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6021
6022           if (! value)
6023             /* If we are doing the bookkeeping for an element that was
6024                directly output as a constructor, we must update
6025                constructor_unfilled_index.  */
6026             constructor_unfilled_index = constructor_index;
6027         }
6028       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6029         {
6030           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6031
6032          /* Do a basic check of initializer size.  Note that vectors
6033             always have a fixed size derived from their type.  */
6034           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6035             {
6036               pedwarn_init ("excess elements in vector initializer");
6037               break;
6038             }
6039
6040           /* Now output the actual element.  */
6041           if (value)
6042             output_init_element (value, elttype, constructor_index, 1);
6043
6044           constructor_index
6045             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6046
6047           if (! value)
6048             /* If we are doing the bookkeeping for an element that was
6049                directly output as a constructor, we must update
6050                constructor_unfilled_index.  */
6051             constructor_unfilled_index = constructor_index;
6052         }
6053
6054       /* Handle the sole element allowed in a braced initializer
6055          for a scalar variable.  */
6056       else if (constructor_fields == 0)
6057         {
6058           pedwarn_init ("excess elements in scalar initializer");
6059           break;
6060         }
6061       else
6062         {
6063           if (value)
6064             output_init_element (value, constructor_type, NULL_TREE, 1);
6065           constructor_fields = 0;
6066         }
6067
6068       /* Handle range initializers either at this level or anywhere higher
6069          in the designator stack.  */
6070       if (constructor_range_stack)
6071         {
6072           struct constructor_range_stack *p, *range_stack;
6073           int finish = 0;
6074
6075           range_stack = constructor_range_stack;
6076           constructor_range_stack = 0;
6077           while (constructor_stack != range_stack->stack)
6078             {
6079               if (!constructor_stack->implicit)
6080                 abort ();
6081               process_init_element (pop_init_level (1));
6082             }
6083           for (p = range_stack;
6084                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6085                p = p->prev)
6086             {
6087               if (!constructor_stack->implicit)
6088                 abort ();
6089               process_init_element (pop_init_level (1));
6090             }
6091
6092           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6093           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6094             finish = 1;
6095
6096           while (1)
6097             {
6098               constructor_index = p->index;
6099               constructor_fields = p->fields;
6100               if (finish && p->range_end && p->index == p->range_start)
6101                 {
6102                   finish = 0;
6103                   p->prev = 0;
6104                 }
6105               p = p->next;
6106               if (!p)
6107                 break;
6108               push_init_level (2);
6109               p->stack = constructor_stack;
6110               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6111                 p->index = p->range_start;
6112             }
6113
6114           if (!finish)
6115             constructor_range_stack = range_stack;
6116           continue;
6117         }
6118
6119       break;
6120     }
6121
6122   constructor_range_stack = 0;
6123 }
6124 \f
6125 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6126    (guaranteed to be 'volatile' or null) and ARGS (represented using
6127    an ASM_EXPR node).  */
6128 tree
6129 build_asm_stmt (tree cv_qualifier, tree args)
6130 {
6131   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6132     ASM_VOLATILE_P (args) = 1;
6133   return add_stmt (args);
6134 }
6135
6136 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6137    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6138    SIMPLE indicates whether there was anything at all after the
6139    string in the asm expression -- asm("blah") and asm("blah" : )
6140    are subtly different.  We use a ASM_EXPR node to represent this.  */
6141 tree
6142 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6143                 bool simple)
6144 {
6145   tree tail;
6146   tree args;
6147   int i;
6148   const char *constraint;
6149   bool allows_mem, allows_reg, is_inout;
6150   int ninputs;
6151   int noutputs;
6152
6153   ninputs = list_length (inputs);
6154   noutputs = list_length (outputs);
6155
6156   /* Remove output conversions that change the type but not the mode.  */
6157   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6158     {
6159       tree output = TREE_VALUE (tail);
6160       STRIP_NOPS (output);
6161       TREE_VALUE (tail) = output;
6162       lvalue_or_else (output, "invalid lvalue in asm statement");
6163
6164       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6165
6166       if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
6167                                     &allows_mem, &allows_reg, &is_inout))
6168         {
6169           /* By marking this operand as erroneous, we will not try
6170           to process this operand again in expand_asm_operands.  */
6171           TREE_VALUE (tail) = error_mark_node;
6172           continue;
6173         }
6174
6175       /* If the operand is a DECL that is going to end up in
6176         memory, assume it is addressable.  This is a bit more
6177         conservative than it would ideally be; the exact test is
6178         buried deep in expand_asm_operands and depends on the
6179         DECL_RTL for the OPERAND -- which we don't have at this
6180         point.  */
6181       if (!allows_reg && DECL_P (output))
6182         c_mark_addressable (output);
6183     }
6184
6185   /* Perform default conversions on array and function inputs.
6186      Don't do this for other types as it would screw up operands
6187      expected to be in memory.  */
6188   for (tail = inputs; tail; tail = TREE_CHAIN (tail))
6189     TREE_VALUE (tail) = default_function_array_conversion (TREE_VALUE (tail));
6190
6191   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6192
6193   /* Simple asm statements are treated as volatile.  */
6194   if (simple)
6195     {
6196       ASM_VOLATILE_P (args) = 1;
6197       ASM_INPUT_P (args) = 1;
6198     }
6199   return args;
6200 }
6201
6202 /* Expand an ASM statement with operands, handling output operands
6203    that are not variables or INDIRECT_REFS by transforming such
6204    cases into cases that expand_asm_operands can handle.
6205
6206    Arguments are same as for expand_asm_operands.  */
6207
6208 void
6209 c_expand_asm_operands (tree string, tree outputs, tree inputs,
6210                        tree clobbers, int vol, location_t locus)
6211 {
6212   int noutputs = list_length (outputs);
6213   int i;
6214   /* o[I] is the place that output number I should be written.  */
6215   tree *o = alloca (noutputs * sizeof (tree));
6216   tree tail;
6217
6218   /* Record the contents of OUTPUTS before it is modified.  */
6219   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
6220     {
6221       o[i] = TREE_VALUE (tail);
6222       if (o[i] == error_mark_node)
6223         return;
6224     }
6225
6226   /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
6227      OUTPUTS some trees for where the values were actually stored.  */
6228   expand_asm_operands (string, outputs, inputs, clobbers, vol, locus);
6229
6230   /* Copy all the intermediate outputs into the specified outputs.  */
6231   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
6232     {
6233       if (o[i] != TREE_VALUE (tail))
6234         {
6235           expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)),
6236                        NULL_RTX, VOIDmode, EXPAND_NORMAL);
6237           free_temp_slots ();
6238
6239           /* Restore the original value so that it's correct the next
6240              time we expand this function.  */
6241           TREE_VALUE (tail) = o[i];
6242         }
6243       /* Detect modification of read-only values.
6244          (Otherwise done by build_modify_expr.)  */
6245       else
6246         {
6247           tree type = TREE_TYPE (o[i]);
6248           if (TREE_READONLY (o[i])
6249               || TYPE_READONLY (type)
6250               || ((TREE_CODE (type) == RECORD_TYPE
6251                    || TREE_CODE (type) == UNION_TYPE)
6252                   && C_TYPE_FIELDS_READONLY (type)))
6253             readonly_error (o[i], "modification by `asm'");
6254         }
6255     }
6256
6257   /* Those MODIFY_EXPRs could do autoincrements.  */
6258   emit_queue ();
6259 }
6260 \f
6261 /* Expand a C `return' statement.
6262    RETVAL is the expression for what to return,
6263    or a null pointer for `return;' with no value.  */
6264
6265 tree
6266 c_expand_return (tree retval)
6267 {
6268   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
6269
6270   if (TREE_THIS_VOLATILE (current_function_decl))
6271     warning ("function declared `noreturn' has a `return' statement");
6272
6273   if (!retval)
6274     {
6275       current_function_returns_null = 1;
6276       if ((warn_return_type || flag_isoc99)
6277           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6278         pedwarn_c99 ("`return' with no value, in function returning non-void");
6279     }
6280   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6281     {
6282       current_function_returns_null = 1;
6283       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6284         pedwarn ("`return' with a value, in function returning void");
6285     }
6286   else
6287     {
6288       tree t = convert_for_assignment (valtype, retval, _("return"),
6289                                        NULL_TREE, NULL_TREE, 0);
6290       tree res = DECL_RESULT (current_function_decl);
6291       tree inner;
6292
6293       current_function_returns_value = 1;
6294       if (t == error_mark_node)
6295         return NULL_TREE;
6296
6297       inner = t = convert (TREE_TYPE (res), t);
6298
6299       /* Strip any conversions, additions, and subtractions, and see if
6300          we are returning the address of a local variable.  Warn if so.  */
6301       while (1)
6302         {
6303           switch (TREE_CODE (inner))
6304             {
6305             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6306             case PLUS_EXPR:
6307               inner = TREE_OPERAND (inner, 0);
6308               continue;
6309
6310             case MINUS_EXPR:
6311               /* If the second operand of the MINUS_EXPR has a pointer
6312                  type (or is converted from it), this may be valid, so
6313                  don't give a warning.  */
6314               {
6315                 tree op1 = TREE_OPERAND (inner, 1);
6316
6317                 while (! POINTER_TYPE_P (TREE_TYPE (op1))
6318                        && (TREE_CODE (op1) == NOP_EXPR
6319                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6320                            || TREE_CODE (op1) == CONVERT_EXPR))
6321                   op1 = TREE_OPERAND (op1, 0);
6322
6323                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6324                   break;
6325
6326                 inner = TREE_OPERAND (inner, 0);
6327                 continue;
6328               }
6329
6330             case ADDR_EXPR:
6331               inner = TREE_OPERAND (inner, 0);
6332
6333               while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
6334                 inner = TREE_OPERAND (inner, 0);
6335
6336               if (DECL_P (inner)
6337                   && ! DECL_EXTERNAL (inner)
6338                   && ! TREE_STATIC (inner)
6339                   && DECL_CONTEXT (inner) == current_function_decl)
6340                 warning ("function returns address of local variable");
6341               break;
6342
6343             default:
6344               break;
6345             }
6346
6347           break;
6348         }
6349
6350       retval = build (MODIFY_EXPR, TREE_TYPE (res), res, t);
6351     }
6352
6353  return add_stmt (build_return_stmt (retval));
6354 }
6355 \f
6356 struct c_switch {
6357   /* The SWITCH_STMT being built.  */
6358   tree switch_stmt;
6359   /* A splay-tree mapping the low element of a case range to the high
6360      element, or NULL_TREE if there is no high element.  Used to
6361      determine whether or not a new case label duplicates an old case
6362      label.  We need a tree, rather than simply a hash table, because
6363      of the GNU case range extension.  */
6364   splay_tree cases;
6365   /* The next node on the stack.  */
6366   struct c_switch *next;
6367 };
6368
6369 /* A stack of the currently active switch statements.  The innermost
6370    switch statement is on the top of the stack.  There is no need to
6371    mark the stack for garbage collection because it is only active
6372    during the processing of the body of a function, and we never
6373    collect at that point.  */
6374
6375 static struct c_switch *switch_stack;
6376
6377 /* Start a C switch statement, testing expression EXP.  Return the new
6378    SWITCH_STMT.  */
6379
6380 tree
6381 c_start_case (tree exp)
6382 {
6383   enum tree_code code;
6384   tree type, orig_type = error_mark_node;
6385   struct c_switch *cs;
6386
6387   if (exp != error_mark_node)
6388     {
6389       code = TREE_CODE (TREE_TYPE (exp));
6390       orig_type = TREE_TYPE (exp);
6391
6392       if (! INTEGRAL_TYPE_P (orig_type)
6393           && code != ERROR_MARK)
6394         {
6395           error ("switch quantity not an integer");
6396           exp = integer_zero_node;
6397         }
6398       else
6399         {
6400           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6401
6402           if (warn_traditional && !in_system_header
6403               && (type == long_integer_type_node
6404                   || type == long_unsigned_type_node))
6405             warning ("`long' switch expression not converted to `int' in ISO C");
6406
6407           exp = default_conversion (exp);
6408           type = TREE_TYPE (exp);
6409         }
6410     }
6411
6412   /* Add this new SWITCH_STMT to the stack.  */
6413   cs = xmalloc (sizeof (*cs));
6414   cs->switch_stmt = build_stmt (SWITCH_STMT, exp, NULL_TREE, orig_type);
6415   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6416   cs->next = switch_stack;
6417   switch_stack = cs;
6418
6419   return add_stmt (switch_stack->switch_stmt);
6420 }
6421
6422 /* Process a case label.  */
6423
6424 tree
6425 do_case (tree low_value, tree high_value)
6426 {
6427   tree label = NULL_TREE;
6428
6429   if (switch_stack)
6430     {
6431       label = c_add_case_label (switch_stack->cases,
6432                                 SWITCH_COND (switch_stack->switch_stmt),
6433                                 low_value, high_value);
6434       if (label == error_mark_node)
6435         label = NULL_TREE;
6436     }
6437   else if (low_value)
6438     error ("case label not within a switch statement");
6439   else
6440     error ("`default' label not within a switch statement");
6441
6442   return label;
6443 }
6444
6445 /* Finish the switch statement.  */
6446
6447 void
6448 c_finish_case (tree body)
6449 {
6450   struct c_switch *cs = switch_stack;
6451
6452   SWITCH_BODY (cs->switch_stmt) = body;
6453
6454   /* Emit warnings as needed.  */
6455   c_do_switch_warnings (cs->cases, cs->switch_stmt);
6456
6457   /* Pop the stack.  */
6458   switch_stack = switch_stack->next;
6459   splay_tree_delete (cs->cases);
6460   free (cs);
6461 }
6462 \f
6463 /* Keep a stack of if statements.  We record the number of compound
6464    statements seen up to the if keyword, as well as the line number
6465    and file of the if.  If a potentially ambiguous else is seen, that
6466    fact is recorded; the warning is issued when we can be sure that
6467    the enclosing if statement does not have an else branch.  */
6468 typedef struct
6469 {
6470   tree if_stmt;
6471   location_t empty_locus;
6472   int compstmt_count;
6473   int stmt_count;
6474   unsigned int needs_warning : 1;
6475   unsigned int saw_else : 1;
6476 } if_elt;
6477
6478 static if_elt *if_stack;
6479
6480 /* Amount of space in the if statement stack.  */
6481 static int if_stack_space = 0;
6482
6483 /* Stack pointer.  */
6484 static int if_stack_pointer = 0;
6485
6486 /* Begin an if-statement.  */
6487
6488 void
6489 c_begin_if_stmt (void)
6490 {
6491   tree r;
6492   if_elt *elt;
6493
6494   /* Make sure there is enough space on the stack.  */
6495   if (if_stack_space == 0)
6496     {
6497       if_stack_space = 10;
6498       if_stack = xmalloc (10 * sizeof (if_elt));
6499     }
6500   else if (if_stack_space == if_stack_pointer)
6501     {
6502       if_stack_space += 10;
6503       if_stack = xrealloc (if_stack, if_stack_space * sizeof (if_elt));
6504     }
6505
6506   r = add_stmt (build_stmt (COND_EXPR, NULL_TREE, NULL_TREE, NULL_TREE));
6507
6508   /* Record this if statement.  */
6509   elt = &if_stack[if_stack_pointer++];
6510   memset (elt, 0, sizeof (*elt));
6511   elt->if_stmt = r;
6512 }
6513
6514 /* Record the start of an if-then, and record the start of it
6515    for ambiguous else detection.
6516
6517    COND is the condition for the if-then statement.
6518
6519    IF_STMT is the statement node that has already been created for
6520    this if-then statement.  It is created before parsing the
6521    condition to keep line number information accurate.  */
6522
6523 void
6524 c_finish_if_cond (tree cond, int compstmt_count, int stmt_count)
6525 {
6526   if_elt *elt = &if_stack[if_stack_pointer - 1];
6527   elt->compstmt_count = compstmt_count;
6528   elt->stmt_count = stmt_count;
6529   COND_EXPR_COND (elt->if_stmt) = lang_hooks.truthvalue_conversion (cond);
6530 }
6531
6532 /* Called after the then-clause for an if-statement is processed.  */
6533
6534 void
6535 c_finish_then (tree then_stmt)
6536 {
6537   if_elt *elt = &if_stack[if_stack_pointer - 1];
6538   COND_EXPR_THEN (elt->if_stmt) = then_stmt;
6539   elt->empty_locus = input_location;
6540 }
6541
6542 /* Called between the then-clause and the else-clause
6543    of an if-then-else.  */
6544
6545 void
6546 c_begin_else (int stmt_count)
6547 {
6548   if_elt *elt = &if_stack[if_stack_pointer - 1];
6549
6550   /* An ambiguous else warning must be generated for the enclosing if
6551      statement, unless we see an else branch for that one, too.  */
6552   if (warn_parentheses
6553       && if_stack_pointer > 1
6554       && (elt[0].compstmt_count == elt[-1].compstmt_count))
6555     elt[-1].needs_warning = 1;
6556
6557   /* Even if a nested if statement had an else branch, it can't be
6558      ambiguous if this one also has an else.  So don't warn in that
6559      case.  Also don't warn for any if statements nested in this else.  */
6560   elt->needs_warning = 0;
6561   elt->compstmt_count--;
6562   elt->saw_else = 1;
6563   elt->stmt_count = stmt_count;
6564 }
6565
6566 /* Called after the else-clause for an if-statement is processed.  */
6567
6568 void
6569 c_finish_else (tree else_stmt)
6570 {
6571   if_elt *elt = &if_stack[if_stack_pointer - 1];
6572   COND_EXPR_ELSE (elt->if_stmt) = else_stmt;
6573   elt->empty_locus = input_location;
6574 }
6575
6576 /* Record the end of an if-then.  Optionally warn if a nested
6577    if statement had an ambiguous else clause.  */
6578
6579 void
6580 c_finish_if_stmt (int stmt_count)
6581 {
6582   if_elt *elt = &if_stack[--if_stack_pointer];
6583
6584   if (COND_EXPR_ELSE (elt->if_stmt) == NULL)
6585     COND_EXPR_ELSE (elt->if_stmt) = build_empty_stmt ();
6586
6587   if (elt->needs_warning)
6588     warning ("%Hsuggest explicit braces to avoid ambiguous `else'",
6589              EXPR_LOCUS (elt->if_stmt));
6590
6591   if (extra_warnings && stmt_count == elt->stmt_count)
6592     {
6593       if (elt->saw_else)
6594         warning ("%Hempty body in an else-statement", &elt->empty_locus);
6595       else
6596         warning ("%Hempty body in an if-statement", &elt->empty_locus);
6597     }
6598 }
6599 \f
6600 /* Begin a while statement.  Returns a newly created WHILE_STMT if
6601    appropriate.  */
6602
6603 tree
6604 c_begin_while_stmt (void)
6605 {
6606   tree r;
6607   r = add_stmt (build_stmt (WHILE_STMT, NULL_TREE, NULL_TREE));
6608   return r;
6609 }
6610
6611 void
6612 c_finish_while_stmt_cond (tree cond, tree while_stmt)
6613 {
6614   WHILE_COND (while_stmt) = (*lang_hooks.truthvalue_conversion) (cond);
6615 }
6616
6617 void
6618 c_finish_while_stmt (tree body, tree while_stmt)
6619 {
6620   WHILE_BODY (while_stmt) = body;
6621 }
6622 \f
6623 /* Create a for statement.  */
6624
6625 tree
6626 c_begin_for_stmt (void)
6627 {
6628   tree r;
6629   r = add_stmt (build_stmt (FOR_STMT, NULL_TREE, NULL_TREE,
6630                             NULL_TREE, NULL_TREE));
6631   FOR_INIT_STMT (r) = push_stmt_list ();
6632   return r;
6633 }
6634
6635 void
6636 c_finish_for_stmt_init (tree for_stmt)
6637 {
6638   FOR_INIT_STMT (for_stmt) = pop_stmt_list (FOR_INIT_STMT (for_stmt));
6639 }
6640
6641 void
6642 c_finish_for_stmt_cond (tree cond, tree for_stmt)
6643 {
6644   if (cond)
6645     FOR_COND (for_stmt) = lang_hooks.truthvalue_conversion (cond);
6646 }
6647
6648 void
6649 c_finish_for_stmt_incr (tree expr, tree for_stmt)
6650 {
6651   FOR_EXPR (for_stmt) = expr;
6652 }
6653
6654 void
6655 c_finish_for_stmt (tree body, tree for_stmt)
6656 {
6657   FOR_BODY (for_stmt) = body;
6658 }
6659 \f
6660 /* Create a statement expression.  */
6661
6662 tree
6663 c_begin_stmt_expr (void)
6664 {
6665   tree ret;
6666
6667   /* We must force a BLOCK for this level so that, if it is not expanded
6668      later, there is a way to turn off the entire subtree of blocks that
6669      are contained in it.  */
6670   keep_next_level ();
6671   ret = c_begin_compound_stmt (true);
6672
6673   /* Mark the current statement list as belonging to a statement list.  */
6674   STATEMENT_LIST_STMT_EXPR (ret) = 1;
6675
6676   return ret;
6677 }
6678
6679 tree
6680 c_finish_stmt_expr (tree body)
6681 {
6682   tree ret, last, type;
6683   tree *last_p;
6684
6685   body = c_end_compound_stmt (body, true);
6686
6687   /* Locate the last statement in BODY.  */
6688   last = body, last_p = &body;
6689   if (TREE_CODE (last) == BIND_EXPR)
6690     {
6691       last_p = &BIND_EXPR_BODY (last);
6692       last = BIND_EXPR_BODY (last);
6693     }
6694   if (TREE_CODE (last) == STATEMENT_LIST)
6695     {
6696       tree_stmt_iterator i = tsi_last (last);
6697       if (tsi_end_p (i))
6698         {
6699           type = void_type_node;
6700           /* ??? Warn */
6701           goto no_expr;
6702         }
6703       else
6704         {
6705           last_p = tsi_stmt_ptr (i);
6706           last = *last_p;
6707         }
6708     }
6709
6710   /* If the last statement is an EXPR_STMT, then unwrap it.  Otherwise
6711      voidify_wrapper_expr will stuff it inside a MODIFY_EXPR and we'll
6712      fail gimplification.  */
6713   /* ??? Should we go ahead and perform voidify_wrapper_expr here?
6714      We've got about all the information we need here.  All we'd have
6715      to do even for proper type safety is to create, in effect,
6716         ( ({ ...; tmp = last; }), tmp )
6717      I.e. a COMPOUND_EXPR with the rhs being the compiler temporary.
6718      Not going to try this now, since it's not clear what should
6719      happen (wrt bindings) with new temporaries at this stage.  It's
6720      easier once we begin gimplification.  */
6721   if (TREE_CODE (last) == EXPR_STMT)
6722     *last_p = last = EXPR_STMT_EXPR (last);
6723
6724   /* Extract the type of said expression.  */
6725   type = TREE_TYPE (last);
6726   if (!type)
6727     type = void_type_node;
6728
6729  no_expr:
6730   /* If what's left is compound, make sure we've got a BIND_EXPR, and
6731      that it has the proper type.  */
6732   ret = body;
6733   if (TREE_CODE (ret) == STATEMENT_LIST)
6734     ret = build (BIND_EXPR, type, NULL, ret, NULL);
6735   else if (TREE_CODE (ret) == BIND_EXPR)
6736     TREE_TYPE (ret) = type;
6737
6738   return ret;
6739 }
6740 \f
6741 /* Begin and end compound statements.  This is as simple as pushing
6742    and popping new statement lists from the tree.  */
6743
6744 tree
6745 c_begin_compound_stmt (bool do_scope)
6746 {
6747   tree stmt = push_stmt_list ();
6748   if (do_scope)
6749     {
6750       push_scope ();
6751       clear_last_expr ();
6752     }
6753   return stmt;
6754 }
6755
6756 tree
6757 c_end_compound_stmt (tree stmt, bool do_scope)
6758 {
6759   tree block = NULL;
6760
6761   if (do_scope)
6762     {
6763       if (c_dialect_objc ())
6764         objc_clear_super_receiver ();
6765       block = pop_scope ();
6766     }
6767
6768   stmt = pop_stmt_list (stmt);
6769   stmt = c_build_bind_expr (block, stmt);
6770
6771   /* If this compound statement is nested immediately inside a statement
6772      expression, then force a BIND_EXPR to be created.  Otherwise we'll
6773      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
6774      STATEMENT_LISTs merge, and thus we can lose track of what statement
6775      was really last.  */
6776   if (cur_stmt_list
6777       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
6778       && TREE_CODE (stmt) != BIND_EXPR)
6779     {
6780       stmt = build (BIND_EXPR, void_type_node, NULL, stmt, NULL);
6781       TREE_SIDE_EFFECTS (stmt) = 1;
6782     }
6783
6784   return stmt;
6785 }
6786
6787 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
6788    when the current scope is exited.  EH_ONLY is true when this is not
6789    meant to apply to normal control flow transfer.  */
6790
6791 void
6792 push_cleanup (tree decl ATTRIBUTE_UNUSED, tree cleanup, bool eh_only)
6793 {
6794   enum tree_code code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
6795   tree stmt = build_stmt (code, NULL, cleanup);
6796   add_stmt (stmt);
6797   TREE_OPERAND (stmt, 0) = push_stmt_list ();
6798 }
6799 \f
6800 /* Build a binary-operation expression without default conversions.
6801    CODE is the kind of expression to build.
6802    This function differs from `build' in several ways:
6803    the data type of the result is computed and recorded in it,
6804    warnings are generated if arg data types are invalid,
6805    special handling for addition and subtraction of pointers is known,
6806    and some optimization is done (operations on narrow ints
6807    are done in the narrower type when that gives the same result).
6808    Constant folding is also done before the result is returned.
6809
6810    Note that the operands will never have enumeral types, or function
6811    or array types, because either they will have the default conversions
6812    performed or they have both just been converted to some other type in which
6813    the arithmetic is to be done.  */
6814
6815 tree
6816 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
6817                  int convert_p)
6818 {
6819   tree type0, type1;
6820   enum tree_code code0, code1;
6821   tree op0, op1;
6822
6823   /* Expression code to give to the expression when it is built.
6824      Normally this is CODE, which is what the caller asked for,
6825      but in some special cases we change it.  */
6826   enum tree_code resultcode = code;
6827
6828   /* Data type in which the computation is to be performed.
6829      In the simplest cases this is the common type of the arguments.  */
6830   tree result_type = NULL;
6831
6832   /* Nonzero means operands have already been type-converted
6833      in whatever way is necessary.
6834      Zero means they need to be converted to RESULT_TYPE.  */
6835   int converted = 0;
6836
6837   /* Nonzero means create the expression with this type, rather than
6838      RESULT_TYPE.  */
6839   tree build_type = 0;
6840
6841   /* Nonzero means after finally constructing the expression
6842      convert it to this type.  */
6843   tree final_type = 0;
6844
6845   /* Nonzero if this is an operation like MIN or MAX which can
6846      safely be computed in short if both args are promoted shorts.
6847      Also implies COMMON.
6848      -1 indicates a bitwise operation; this makes a difference
6849      in the exact conditions for when it is safe to do the operation
6850      in a narrower mode.  */
6851   int shorten = 0;
6852
6853   /* Nonzero if this is a comparison operation;
6854      if both args are promoted shorts, compare the original shorts.
6855      Also implies COMMON.  */
6856   int short_compare = 0;
6857
6858   /* Nonzero if this is a right-shift operation, which can be computed on the
6859      original short and then promoted if the operand is a promoted short.  */
6860   int short_shift = 0;
6861
6862   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
6863   int common = 0;
6864
6865   if (convert_p)
6866     {
6867       op0 = default_conversion (orig_op0);
6868       op1 = default_conversion (orig_op1);
6869     }
6870   else
6871     {
6872       op0 = orig_op0;
6873       op1 = orig_op1;
6874     }
6875
6876   type0 = TREE_TYPE (op0);
6877   type1 = TREE_TYPE (op1);
6878
6879   /* The expression codes of the data types of the arguments tell us
6880      whether the arguments are integers, floating, pointers, etc.  */
6881   code0 = TREE_CODE (type0);
6882   code1 = TREE_CODE (type1);
6883
6884   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
6885   STRIP_TYPE_NOPS (op0);
6886   STRIP_TYPE_NOPS (op1);
6887
6888   /* If an error was already reported for one of the arguments,
6889      avoid reporting another error.  */
6890
6891   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
6892     return error_mark_node;
6893
6894   switch (code)
6895     {
6896     case PLUS_EXPR:
6897       /* Handle the pointer + int case.  */
6898       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6899         return pointer_int_sum (PLUS_EXPR, op0, op1);
6900       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
6901         return pointer_int_sum (PLUS_EXPR, op1, op0);
6902       else
6903         common = 1;
6904       break;
6905
6906     case MINUS_EXPR:
6907       /* Subtraction of two similar pointers.
6908          We must subtract them as integers, then divide by object size.  */
6909       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
6910           && comp_target_types (type0, type1, 1))
6911         return pointer_diff (op0, op1);
6912       /* Handle pointer minus int.  Just like pointer plus int.  */
6913       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
6914         return pointer_int_sum (MINUS_EXPR, op0, op1);
6915       else
6916         common = 1;
6917       break;
6918
6919     case MULT_EXPR:
6920       common = 1;
6921       break;
6922
6923     case TRUNC_DIV_EXPR:
6924     case CEIL_DIV_EXPR:
6925     case FLOOR_DIV_EXPR:
6926     case ROUND_DIV_EXPR:
6927     case EXACT_DIV_EXPR:
6928       /* Floating point division by zero is a legitimate way to obtain
6929          infinities and NaNs.  */
6930       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6931         warning ("division by zero");
6932
6933       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
6934            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
6935           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
6936               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
6937         {
6938           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
6939             resultcode = RDIV_EXPR;
6940           else
6941             /* Although it would be tempting to shorten always here, that
6942                loses on some targets, since the modulo instruction is
6943                undefined if the quotient can't be represented in the
6944                computation mode.  We shorten only if unsigned or if
6945                dividing by something we know != -1.  */
6946             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
6947                        || (TREE_CODE (op1) == INTEGER_CST
6948                            && ! integer_all_onesp (op1)));
6949           common = 1;
6950         }
6951       break;
6952
6953     case BIT_AND_EXPR:
6954     case BIT_IOR_EXPR:
6955     case BIT_XOR_EXPR:
6956       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
6957         shorten = -1;
6958       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
6959         common = 1;
6960       break;
6961
6962     case TRUNC_MOD_EXPR:
6963     case FLOOR_MOD_EXPR:
6964       if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
6965         warning ("division by zero");
6966
6967       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
6968         {
6969           /* Although it would be tempting to shorten always here, that loses
6970              on some targets, since the modulo instruction is undefined if the
6971              quotient can't be represented in the computation mode.  We shorten
6972              only if unsigned or if dividing by something we know != -1.  */
6973           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
6974                      || (TREE_CODE (op1) == INTEGER_CST
6975                          && ! integer_all_onesp (op1)));
6976           common = 1;
6977         }
6978       break;
6979
6980     case TRUTH_ANDIF_EXPR:
6981     case TRUTH_ORIF_EXPR:
6982     case TRUTH_AND_EXPR:
6983     case TRUTH_OR_EXPR:
6984     case TRUTH_XOR_EXPR:
6985       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
6986            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
6987           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
6988               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
6989         {
6990           /* Result of these operations is always an int,
6991              but that does not mean the operands should be
6992              converted to ints!  */
6993           result_type = integer_type_node;
6994           op0 = lang_hooks.truthvalue_conversion (op0);
6995           op1 = lang_hooks.truthvalue_conversion (op1);
6996           converted = 1;
6997         }
6998       break;
6999
7000       /* Shift operations: result has same type as first operand;
7001          always convert second operand to int.
7002          Also set SHORT_SHIFT if shifting rightward.  */
7003
7004     case RSHIFT_EXPR:
7005       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7006         {
7007           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7008             {
7009               if (tree_int_cst_sgn (op1) < 0)
7010                 warning ("right shift count is negative");
7011               else
7012                 {
7013                   if (! integer_zerop (op1))
7014                     short_shift = 1;
7015
7016                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7017                     warning ("right shift count >= width of type");
7018                 }
7019             }
7020
7021           /* Use the type of the value to be shifted.  */
7022           result_type = type0;
7023           /* Convert the shift-count to an integer, regardless of size
7024              of value being shifted.  */
7025           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7026             op1 = convert (integer_type_node, op1);
7027           /* Avoid converting op1 to result_type later.  */
7028           converted = 1;
7029         }
7030       break;
7031
7032     case LSHIFT_EXPR:
7033       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7034         {
7035           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7036             {
7037               if (tree_int_cst_sgn (op1) < 0)
7038                 warning ("left shift count is negative");
7039
7040               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7041                 warning ("left shift count >= width of type");
7042             }
7043
7044           /* Use the type of the value to be shifted.  */
7045           result_type = type0;
7046           /* Convert the shift-count to an integer, regardless of size
7047              of value being shifted.  */
7048           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7049             op1 = convert (integer_type_node, op1);
7050           /* Avoid converting op1 to result_type later.  */
7051           converted = 1;
7052         }
7053       break;
7054
7055     case RROTATE_EXPR:
7056     case LROTATE_EXPR:
7057       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7058         {
7059           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7060             {
7061               if (tree_int_cst_sgn (op1) < 0)
7062                 warning ("shift count is negative");
7063               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7064                 warning ("shift count >= width of type");
7065             }
7066
7067           /* Use the type of the value to be shifted.  */
7068           result_type = type0;
7069           /* Convert the shift-count to an integer, regardless of size
7070              of value being shifted.  */
7071           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7072             op1 = convert (integer_type_node, op1);
7073           /* Avoid converting op1 to result_type later.  */
7074           converted = 1;
7075         }
7076       break;
7077
7078     case EQ_EXPR:
7079     case NE_EXPR:
7080       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
7081         warning ("comparing floating point with == or != is unsafe");
7082       /* Result of comparison is always int,
7083          but don't convert the args to int!  */
7084       build_type = integer_type_node;
7085       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7086            || code0 == COMPLEX_TYPE)
7087           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7088               || code1 == COMPLEX_TYPE))
7089         short_compare = 1;
7090       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7091         {
7092           tree tt0 = TREE_TYPE (type0);
7093           tree tt1 = TREE_TYPE (type1);
7094           /* Anything compares with void *.  void * compares with anything.
7095              Otherwise, the targets must be compatible
7096              and both must be object or both incomplete.  */
7097           if (comp_target_types (type0, type1, 1))
7098             result_type = common_pointer_type (type0, type1);
7099           else if (VOID_TYPE_P (tt0))
7100             {
7101               /* op0 != orig_op0 detects the case of something
7102                  whose value is 0 but which isn't a valid null ptr const.  */
7103               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7104                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7105                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7106             }
7107           else if (VOID_TYPE_P (tt1))
7108             {
7109               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7110                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7111                 pedwarn ("ISO C forbids comparison of `void *' with function pointer");
7112             }
7113           else
7114             pedwarn ("comparison of distinct pointer types lacks a cast");
7115
7116           if (result_type == NULL_TREE)
7117             result_type = ptr_type_node;
7118         }
7119       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7120                && integer_zerop (op1))
7121         result_type = type0;
7122       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7123                && integer_zerop (op0))
7124         result_type = type1;
7125       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7126         {
7127           result_type = type0;
7128           pedwarn ("comparison between pointer and integer");
7129         }
7130       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7131         {
7132           result_type = type1;
7133           pedwarn ("comparison between pointer and integer");
7134         }
7135       break;
7136
7137     case MAX_EXPR:
7138     case MIN_EXPR:
7139       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7140           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7141         shorten = 1;
7142       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7143         {
7144           if (comp_target_types (type0, type1, 1))
7145             {
7146               result_type = common_pointer_type (type0, type1);
7147               if (pedantic
7148                   && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7149                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7150             }
7151           else
7152             {
7153               result_type = ptr_type_node;
7154               pedwarn ("comparison of distinct pointer types lacks a cast");
7155             }
7156         }
7157       break;
7158
7159     case LE_EXPR:
7160     case GE_EXPR:
7161     case LT_EXPR:
7162     case GT_EXPR:
7163       build_type = integer_type_node;
7164       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7165           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7166         short_compare = 1;
7167       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7168         {
7169           if (comp_target_types (type0, type1, 1))
7170             {
7171               result_type = common_pointer_type (type0, type1);
7172               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7173                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7174                 pedwarn ("comparison of complete and incomplete pointers");
7175               else if (pedantic
7176                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7177                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7178             }
7179           else
7180             {
7181               result_type = ptr_type_node;
7182               pedwarn ("comparison of distinct pointer types lacks a cast");
7183             }
7184         }
7185       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7186                && integer_zerop (op1))
7187         {
7188           result_type = type0;
7189           if (pedantic || extra_warnings)
7190             pedwarn ("ordered comparison of pointer with integer zero");
7191         }
7192       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7193                && integer_zerop (op0))
7194         {
7195           result_type = type1;
7196           if (pedantic)
7197             pedwarn ("ordered comparison of pointer with integer zero");
7198         }
7199       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7200         {
7201           result_type = type0;
7202           pedwarn ("comparison between pointer and integer");
7203         }
7204       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7205         {
7206           result_type = type1;
7207           pedwarn ("comparison between pointer and integer");
7208         }
7209       break;
7210
7211     case UNORDERED_EXPR:
7212     case ORDERED_EXPR:
7213     case UNLT_EXPR:
7214     case UNLE_EXPR:
7215     case UNGT_EXPR:
7216     case UNGE_EXPR:
7217     case UNEQ_EXPR:
7218     case LTGT_EXPR:
7219       build_type = integer_type_node;
7220       if (code0 != REAL_TYPE || code1 != REAL_TYPE)
7221         {
7222           error ("unordered comparison on non-floating point argument");
7223           return error_mark_node;
7224         }
7225       common = 1;
7226       break;
7227
7228     default:
7229       break;
7230     }
7231
7232   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7233     return error_mark_node;
7234
7235   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7236        || code0 == VECTOR_TYPE)
7237       &&
7238       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
7239        || code1 == VECTOR_TYPE))
7240     {
7241       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
7242
7243       if (shorten || common || short_compare)
7244         result_type = common_type (type0, type1);
7245
7246       /* For certain operations (which identify themselves by shorten != 0)
7247          if both args were extended from the same smaller type,
7248          do the arithmetic in that type and then extend.
7249
7250          shorten !=0 and !=1 indicates a bitwise operation.
7251          For them, this optimization is safe only if
7252          both args are zero-extended or both are sign-extended.
7253          Otherwise, we might change the result.
7254          Eg, (short)-1 | (unsigned short)-1 is (int)-1
7255          but calculated in (unsigned short) it would be (unsigned short)-1.  */
7256
7257       if (shorten && none_complex)
7258         {
7259           int unsigned0, unsigned1;
7260           tree arg0 = get_narrower (op0, &unsigned0);
7261           tree arg1 = get_narrower (op1, &unsigned1);
7262           /* UNS is 1 if the operation to be done is an unsigned one.  */
7263           int uns = TYPE_UNSIGNED (result_type);
7264           tree type;
7265
7266           final_type = result_type;
7267
7268           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
7269              but it *requires* conversion to FINAL_TYPE.  */
7270
7271           if ((TYPE_PRECISION (TREE_TYPE (op0))
7272                == TYPE_PRECISION (TREE_TYPE (arg0)))
7273               && TREE_TYPE (op0) != final_type)
7274             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
7275           if ((TYPE_PRECISION (TREE_TYPE (op1))
7276                == TYPE_PRECISION (TREE_TYPE (arg1)))
7277               && TREE_TYPE (op1) != final_type)
7278             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
7279
7280           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
7281
7282           /* For bitwise operations, signedness of nominal type
7283              does not matter.  Consider only how operands were extended.  */
7284           if (shorten == -1)
7285             uns = unsigned0;
7286
7287           /* Note that in all three cases below we refrain from optimizing
7288              an unsigned operation on sign-extended args.
7289              That would not be valid.  */
7290
7291           /* Both args variable: if both extended in same way
7292              from same width, do it in that width.
7293              Do it unsigned if args were zero-extended.  */
7294           if ((TYPE_PRECISION (TREE_TYPE (arg0))
7295                < TYPE_PRECISION (result_type))
7296               && (TYPE_PRECISION (TREE_TYPE (arg1))
7297                   == TYPE_PRECISION (TREE_TYPE (arg0)))
7298               && unsigned0 == unsigned1
7299               && (unsigned0 || !uns))
7300             result_type
7301               = c_common_signed_or_unsigned_type
7302               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
7303           else if (TREE_CODE (arg0) == INTEGER_CST
7304                    && (unsigned1 || !uns)
7305                    && (TYPE_PRECISION (TREE_TYPE (arg1))
7306                        < TYPE_PRECISION (result_type))
7307                    && (type
7308                        = c_common_signed_or_unsigned_type (unsigned1,
7309                                                            TREE_TYPE (arg1)),
7310                        int_fits_type_p (arg0, type)))
7311             result_type = type;
7312           else if (TREE_CODE (arg1) == INTEGER_CST
7313                    && (unsigned0 || !uns)
7314                    && (TYPE_PRECISION (TREE_TYPE (arg0))
7315                        < TYPE_PRECISION (result_type))
7316                    && (type
7317                        = c_common_signed_or_unsigned_type (unsigned0,
7318                                                            TREE_TYPE (arg0)),
7319                        int_fits_type_p (arg1, type)))
7320             result_type = type;
7321         }
7322
7323       /* Shifts can be shortened if shifting right.  */
7324
7325       if (short_shift)
7326         {
7327           int unsigned_arg;
7328           tree arg0 = get_narrower (op0, &unsigned_arg);
7329
7330           final_type = result_type;
7331
7332           if (arg0 == op0 && final_type == TREE_TYPE (op0))
7333             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
7334
7335           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
7336               /* We can shorten only if the shift count is less than the
7337                  number of bits in the smaller type size.  */
7338               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
7339               /* We cannot drop an unsigned shift after sign-extension.  */
7340               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
7341             {
7342               /* Do an unsigned shift if the operand was zero-extended.  */
7343               result_type
7344                 = c_common_signed_or_unsigned_type (unsigned_arg,
7345                                                     TREE_TYPE (arg0));
7346               /* Convert value-to-be-shifted to that type.  */
7347               if (TREE_TYPE (op0) != result_type)
7348                 op0 = convert (result_type, op0);
7349               converted = 1;
7350             }
7351         }
7352
7353       /* Comparison operations are shortened too but differently.
7354          They identify themselves by setting short_compare = 1.  */
7355
7356       if (short_compare)
7357         {
7358           /* Don't write &op0, etc., because that would prevent op0
7359              from being kept in a register.
7360              Instead, make copies of the our local variables and
7361              pass the copies by reference, then copy them back afterward.  */
7362           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
7363           enum tree_code xresultcode = resultcode;
7364           tree val
7365             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
7366
7367           if (val != 0)
7368             return val;
7369
7370           op0 = xop0, op1 = xop1;
7371           converted = 1;
7372           resultcode = xresultcode;
7373
7374           if (warn_sign_compare && skip_evaluation == 0)
7375             {
7376               int op0_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op0));
7377               int op1_signed = ! TYPE_UNSIGNED (TREE_TYPE (orig_op1));
7378               int unsignedp0, unsignedp1;
7379               tree primop0 = get_narrower (op0, &unsignedp0);
7380               tree primop1 = get_narrower (op1, &unsignedp1);
7381
7382               xop0 = orig_op0;
7383               xop1 = orig_op1;
7384               STRIP_TYPE_NOPS (xop0);
7385               STRIP_TYPE_NOPS (xop1);
7386
7387               /* Give warnings for comparisons between signed and unsigned
7388                  quantities that may fail.
7389
7390                  Do the checking based on the original operand trees, so that
7391                  casts will be considered, but default promotions won't be.
7392
7393                  Do not warn if the comparison is being done in a signed type,
7394                  since the signed type will only be chosen if it can represent
7395                  all the values of the unsigned type.  */
7396               if (! TYPE_UNSIGNED (result_type))
7397                 /* OK */;
7398               /* Do not warn if both operands are the same signedness.  */
7399               else if (op0_signed == op1_signed)
7400                 /* OK */;
7401               else
7402                 {
7403                   tree sop, uop;
7404
7405                   if (op0_signed)
7406                     sop = xop0, uop = xop1;
7407                   else
7408                     sop = xop1, uop = xop0;
7409
7410                   /* Do not warn if the signed quantity is an
7411                      unsuffixed integer literal (or some static
7412                      constant expression involving such literals or a
7413                      conditional expression involving such literals)
7414                      and it is non-negative.  */
7415                   if (c_tree_expr_nonnegative_p (sop))
7416                     /* OK */;
7417                   /* Do not warn if the comparison is an equality operation,
7418                      the unsigned quantity is an integral constant, and it
7419                      would fit in the result if the result were signed.  */
7420                   else if (TREE_CODE (uop) == INTEGER_CST
7421                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
7422                            && int_fits_type_p
7423                            (uop, c_common_signed_type (result_type)))
7424                     /* OK */;
7425                   /* Do not warn if the unsigned quantity is an enumeration
7426                      constant and its maximum value would fit in the result
7427                      if the result were signed.  */
7428                   else if (TREE_CODE (uop) == INTEGER_CST
7429                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
7430                            && int_fits_type_p
7431                            (TYPE_MAX_VALUE (TREE_TYPE(uop)),
7432                             c_common_signed_type (result_type)))
7433                     /* OK */;
7434                   else
7435                     warning ("comparison between signed and unsigned");
7436                 }
7437
7438               /* Warn if two unsigned values are being compared in a size
7439                  larger than their original size, and one (and only one) is the
7440                  result of a `~' operator.  This comparison will always fail.
7441
7442                  Also warn if one operand is a constant, and the constant
7443                  does not have all bits set that are set in the ~ operand
7444                  when it is extended.  */
7445
7446               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
7447                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
7448                 {
7449                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
7450                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
7451                                             &unsignedp0);
7452                   else
7453                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
7454                                             &unsignedp1);
7455
7456                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
7457                     {
7458                       tree primop;
7459                       HOST_WIDE_INT constant, mask;
7460                       int unsignedp, bits;
7461
7462                       if (host_integerp (primop0, 0))
7463                         {
7464                           primop = primop1;
7465                           unsignedp = unsignedp1;
7466                           constant = tree_low_cst (primop0, 0);
7467                         }
7468                       else
7469                         {
7470                           primop = primop0;
7471                           unsignedp = unsignedp0;
7472                           constant = tree_low_cst (primop1, 0);
7473                         }
7474
7475                       bits = TYPE_PRECISION (TREE_TYPE (primop));
7476                       if (bits < TYPE_PRECISION (result_type)
7477                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
7478                         {
7479                           mask = (~ (HOST_WIDE_INT) 0) << bits;
7480                           if ((mask & constant) != mask)
7481                             warning ("comparison of promoted ~unsigned with constant");
7482                         }
7483                     }
7484                   else if (unsignedp0 && unsignedp1
7485                            && (TYPE_PRECISION (TREE_TYPE (primop0))
7486                                < TYPE_PRECISION (result_type))
7487                            && (TYPE_PRECISION (TREE_TYPE (primop1))
7488                                < TYPE_PRECISION (result_type)))
7489                     warning ("comparison of promoted ~unsigned with unsigned");
7490                 }
7491             }
7492         }
7493     }
7494
7495   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7496      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7497      Then the expression will be built.
7498      It will be given type FINAL_TYPE if that is nonzero;
7499      otherwise, it will be given type RESULT_TYPE.  */
7500
7501   if (!result_type)
7502     {
7503       binary_op_error (code);
7504       return error_mark_node;
7505     }
7506
7507   if (! converted)
7508     {
7509       if (TREE_TYPE (op0) != result_type)
7510         op0 = convert (result_type, op0);
7511       if (TREE_TYPE (op1) != result_type)
7512         op1 = convert (result_type, op1);
7513     }
7514
7515   if (build_type == NULL_TREE)
7516     build_type = result_type;
7517
7518   {
7519     tree result = build (resultcode, build_type, op0, op1);
7520
7521     /* Treat expressions in initializers specially as they can't trap.  */
7522     result = require_constant_value ? fold_initializer (result)
7523                                     : fold (result);
7524
7525     if (final_type != 0)
7526       result = convert (final_type, result);
7527     return result;
7528   }
7529 }
7530
7531 /* Build the result of __builtin_offsetof.  TYPE is the first argument to
7532    offsetof, i.e. a type.  LIST is a tree_list that encodes component and
7533    array references; PURPOSE is set for the former and VALUE is set for
7534    the later.  */
7535
7536 tree
7537 build_offsetof (tree type, tree list)
7538 {
7539   tree t;
7540
7541   /* Build "*(type *)0".  */
7542   t = convert (build_pointer_type (type), null_pointer_node);
7543   t = build_indirect_ref (t, "");
7544
7545   /* Build COMPONENT and ARRAY_REF expressions as needed.  */
7546   for (list = nreverse (list); list ; list = TREE_CHAIN (list))
7547     if (TREE_PURPOSE (list))
7548       t = build_component_ref (t, TREE_PURPOSE (list));
7549     else
7550       t = build_array_ref (t, TREE_VALUE (list));
7551
7552   /* Finalize the offsetof expression.  For now all we need to do is take
7553      the address of the expression we created, and cast that to an integer
7554      type; this mirrors the traditional macro implementation of offsetof.  */
7555   t = build_unary_op (ADDR_EXPR, t, 0);
7556   return convert (size_type_node, t);
7557 }