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, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (tree, tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (tree, tree);
  81 static int type_lists_compatible_p (tree, tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static tree convert_arguments (tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static void push_array_bounds (int);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (tree, enum lvalue_use);
 106 static int lvalue_p (tree);
 107 static void record_maybe_used_decl (tree);
 108 static int comptypes_internal (tree, tree);
 109 \f/* This is a cache to hold if two types are compatible or not.  */
 110
 111 struct tagged_tu_seen_cache {
 112   const struct tagged_tu_seen_cache * next;
 113   tree t1;
 114   tree t2;
 115   /* The return value of tagged_types_tu_compatible_p if we had seen
 116      these two types already.  */
 117   int val;
 118 };
 119
 120 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 121 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 122
 123 /* Do `exp = require_complete_type (exp);' to make sure exp
 124    does not have an incomplete type.  (That includes void types.)  */
 125
 126 tree
 127 require_complete_type (tree value)
 128 {
 129   tree type = TREE_TYPE (value);
 130
 131   if (value == error_mark_node || type == error_mark_node)
 132     return error_mark_node;
 133
 134   /* First, detect a valid value with a complete type.  */
 135   if (COMPLETE_TYPE_P (type))
 136     return value;
 137
 138   c_incomplete_type_error (value, type);
 139   return error_mark_node;
 140 }
 141
 142 /* Print an error message for invalid use of an incomplete type.
 143    VALUE is the expression that was used (or 0 if that isn't known)
 144    and TYPE is the type that was invalid.  */
 145
 146 void
 147 c_incomplete_type_error (tree value, tree type)
 148 {
 149   const char *type_code_string;
 150
 151   /* Avoid duplicate error message.  */
 152   if (TREE_CODE (type) == ERROR_MARK)
 153     return;
 154
 155   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 156                      || TREE_CODE (value) == PARM_DECL))
 157     error ("%qD has an incomplete type", value);
 158   else
 159     {
 160     retry:
 161       /* We must print an error message.  Be clever about what it says.  */
 162
 163       switch (TREE_CODE (type))
 164         {
 165         case RECORD_TYPE:
 166           type_code_string = "struct";
 167           break;
 168
 169         case UNION_TYPE:
 170           type_code_string = "union";
 171           break;
 172
 173         case ENUMERAL_TYPE:
 174           type_code_string = "enum";
 175           break;
 176
 177         case VOID_TYPE:
 178           error ("invalid use of void expression");
 179           return;
 180
 181         case ARRAY_TYPE:
 182           if (TYPE_DOMAIN (type))
 183             {
 184               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 185                 {
 186                   error ("invalid use of flexible array member");
 187                   return;
 188                 }
 189               type = TREE_TYPE (type);
 190               goto retry;
 191             }
 192           error ("invalid use of array with unspecified bounds");
 193           return;
 194
 195         default:
 196           gcc_unreachable ();
 197         }
 198
 199       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 200         error ("invalid use of undefined type %<%s %E%>",
 201                type_code_string, TYPE_NAME (type));
 202       else
 203         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 204         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 205     }
 206 }
 207
 208 /* Given a type, apply default promotions wrt unnamed function
 209    arguments and return the new type.  */
 210
 211 tree
 212 c_type_promotes_to (tree type)
 213 {
 214   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 215     return double_type_node;
 216
 217   if (c_promoting_integer_type_p (type))
 218     {
 219       /* Preserve unsignedness if not really getting any wider.  */
 220       if (TYPE_UNSIGNED (type)
 221           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 222         return unsigned_type_node;
 223       return integer_type_node;
 224     }
 225
 226   return type;
 227 }
 228
 229 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 230    as well as those of TYPE.  */
 231
 232 static tree
 233 qualify_type (tree type, tree like)
 234 {
 235   return c_build_qualified_type (type,
 236                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 237 }
 238 \f
 239 /* Return the composite type of two compatible types.
 240
 241    We assume that comptypes has already been done and returned
 242    nonzero; if that isn't so, this may crash.  In particular, we
 243    assume that qualifiers match.  */
 244
 245 tree
 246 composite_type (tree t1, tree t2)
 247 {
 248   enum tree_code code1;
 249   enum tree_code code2;
 250   tree attributes;
 251
 252   /* Save time if the two types are the same.  */
 253
 254   if (t1 == t2) return t1;
 255
 256   /* If one type is nonsense, use the other.  */
 257   if (t1 == error_mark_node)
 258     return t2;
 259   if (t2 == error_mark_node)
 260     return t1;
 261
 262   code1 = TREE_CODE (t1);
 263   code2 = TREE_CODE (t2);
 264
 265   /* Merge the attributes.  */
 266   attributes = targetm.merge_type_attributes (t1, t2);
 267
 268   /* If one is an enumerated type and the other is the compatible
 269      integer type, the composite type might be either of the two
 270      (DR#013 question 3).  For consistency, use the enumerated type as
 271      the composite type.  */
 272
 273   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 274     return t1;
 275   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 276     return t2;
 277
 278   gcc_assert (code1 == code2);
 279
 280   switch (code1)
 281     {
 282     case POINTER_TYPE:
 283       /* For two pointers, do this recursively on the target type.  */
 284       {
 285         tree pointed_to_1 = TREE_TYPE (t1);
 286         tree pointed_to_2 = TREE_TYPE (t2);
 287         tree target = composite_type (pointed_to_1, pointed_to_2);
 288         t1 = build_pointer_type (target);
 289         t1 = build_type_attribute_variant (t1, attributes);
 290         return qualify_type (t1, t2);
 291       }
 292
 293     case ARRAY_TYPE:
 294       {
 295         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 296         int quals;
 297         tree unqual_elt;
 298         tree d1 = TYPE_DOMAIN (t1);
 299         tree d2 = TYPE_DOMAIN (t2);
 300         bool d1_variable, d2_variable;
 301         bool d1_zero, d2_zero;
 302
 303         /* We should not have any type quals on arrays at all.  */
 304         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 305
 306         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 307         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 308
 309         d1_variable = (!d1_zero
 310                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 311                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 312         d2_variable = (!d2_zero
 313                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 314                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 315
 316         /* Save space: see if the result is identical to one of the args.  */
 317         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 318             && (d2_variable || d2_zero || !d1_variable))
 319           return build_type_attribute_variant (t1, attributes);
 320         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 321             && (d1_variable || d1_zero || !d2_variable))
 322           return build_type_attribute_variant (t2, attributes);
 323
 324         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 325           return build_type_attribute_variant (t1, attributes);
 326         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 327           return build_type_attribute_variant (t2, attributes);
 328
 329         /* Merge the element types, and have a size if either arg has
 330            one.  We may have qualifiers on the element types.  To set
 331            up TYPE_MAIN_VARIANT correctly, we need to form the
 332            composite of the unqualified types and add the qualifiers
 333            back at the end.  */
 334         quals = TYPE_QUALS (strip_array_types (elt));
 335         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 336         t1 = build_array_type (unqual_elt,
 337                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 338                                              && (d2_variable
 339                                                  || d2_zero
 340                                                  || !d1_variable))
 341                                             ? t1
 342                                             : t2));
 343         t1 = c_build_qualified_type (t1, quals);
 344         return build_type_attribute_variant (t1, attributes);
 345       }
 346
 347     case FUNCTION_TYPE:
 348       /* Function types: prefer the one that specified arg types.
 349          If both do, merge the arg types.  Also merge the return types.  */
 350       {
 351         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 352         tree p1 = TYPE_ARG_TYPES (t1);
 353         tree p2 = TYPE_ARG_TYPES (t2);
 354         int len;
 355         tree newargs, n;
 356         int i;
 357
 358         /* Save space: see if the result is identical to one of the args.  */
 359         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 360           return build_type_attribute_variant (t1, attributes);
 361         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 362           return build_type_attribute_variant (t2, attributes);
 363
 364         /* Simple way if one arg fails to specify argument types.  */
 365         if (TYPE_ARG_TYPES (t1) == 0)
 366          {
 367             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 368             t1 = build_type_attribute_variant (t1, attributes);
 369             return qualify_type (t1, t2);
 370          }
 371         if (TYPE_ARG_TYPES (t2) == 0)
 372          {
 373            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 374            t1 = build_type_attribute_variant (t1, attributes);
 375            return qualify_type (t1, t2);
 376          }
 377
 378         /* If both args specify argument types, we must merge the two
 379            lists, argument by argument.  */
 380         /* Tell global_bindings_p to return false so that variable_size
 381            doesn't die on VLAs in parameter types.  */
 382         c_override_global_bindings_to_false = true;
 383
 384         len = list_length (p1);
 385         newargs = 0;
 386
 387         for (i = 0; i < len; i++)
 388           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 389
 390         n = newargs;
 391
 392         for (; p1;
 393              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 394           {
 395             /* A null type means arg type is not specified.
 396                Take whatever the other function type has.  */
 397             if (TREE_VALUE (p1) == 0)
 398               {
 399                 TREE_VALUE (n) = TREE_VALUE (p2);
 400                 goto parm_done;
 401               }
 402             if (TREE_VALUE (p2) == 0)
 403               {
 404                 TREE_VALUE (n) = TREE_VALUE (p1);
 405                 goto parm_done;
 406               }
 407
 408             /* Given  wait (union {union wait *u; int *i} *)
 409                and  wait (union wait *),
 410                prefer  union wait *  as type of parm.  */
 411             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 412                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 413               {
 414                 tree memb;
 415                 tree mv2 = TREE_VALUE (p2);
 416                 if (mv2 && mv2 != error_mark_node
 417                     && TREE_CODE (mv2) != ARRAY_TYPE)
 418                   mv2 = TYPE_MAIN_VARIANT (mv2);
 419                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 420                      memb; memb = TREE_CHAIN (memb))
 421                   {
 422                     tree mv3 = TREE_TYPE (memb);
 423                     if (mv3 && mv3 != error_mark_node
 424                         && TREE_CODE (mv3) != ARRAY_TYPE)
 425                       mv3 = TYPE_MAIN_VARIANT (mv3);
 426                     if (comptypes (mv3, mv2))
 427                       {
 428                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 429                                                          TREE_VALUE (p2));
 430                         if (pedantic)
 431                           pedwarn ("function types not truly compatible in ISO C");
 432                         goto parm_done;
 433                       }
 434                   }
 435               }
 436             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 437                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 438               {
 439                 tree memb;
 440                 tree mv1 = TREE_VALUE (p1);
 441                 if (mv1 && mv1 != error_mark_node
 442                     && TREE_CODE (mv1) != ARRAY_TYPE)
 443                   mv1 = TYPE_MAIN_VARIANT (mv1);
 444                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 445                      memb; memb = TREE_CHAIN (memb))
 446                   {
 447                     tree mv3 = TREE_TYPE (memb);
 448                     if (mv3 && mv3 != error_mark_node
 449                         && TREE_CODE (mv3) != ARRAY_TYPE)
 450                       mv3 = TYPE_MAIN_VARIANT (mv3);
 451                     if (comptypes (mv3, mv1))
 452                       {
 453                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 454                                                          TREE_VALUE (p1));
 455                         if (pedantic)
 456                           pedwarn ("function types not truly compatible in ISO C");
 457                         goto parm_done;
 458                       }
 459                   }
 460               }
 461             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 462           parm_done: ;
 463           }
 464
 465         c_override_global_bindings_to_false = false;
 466         t1 = build_function_type (valtype, newargs);
 467         t1 = qualify_type (t1, t2);
 468         /* ... falls through ...  */
 469       }
 470
 471     default:
 472       return build_type_attribute_variant (t1, attributes);
 473     }
 474
 475 }
 476
 477 /* Return the type of a conditional expression between pointers to
 478    possibly differently qualified versions of compatible types.
 479
 480    We assume that comp_target_types has already been done and returned
 481    nonzero; if that isn't so, this may crash.  */
 482
 483 static tree
 484 common_pointer_type (tree t1, tree t2)
 485 {
 486   tree attributes;
 487   tree pointed_to_1, mv1;
 488   tree pointed_to_2, mv2;
 489   tree target;
 490
 491   /* Save time if the two types are the same.  */
 492
 493   if (t1 == t2) return t1;
 494
 495   /* If one type is nonsense, use the other.  */
 496   if (t1 == error_mark_node)
 497     return t2;
 498   if (t2 == error_mark_node)
 499     return t1;
 500
 501   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 502               && TREE_CODE (t2) == POINTER_TYPE);
 503
 504   /* Merge the attributes.  */
 505   attributes = targetm.merge_type_attributes (t1, t2);
 506
 507   /* Find the composite type of the target types, and combine the
 508      qualifiers of the two types' targets.  Do not lose qualifiers on
 509      array element types by taking the TYPE_MAIN_VARIANT.  */
 510   mv1 = pointed_to_1 = TREE_TYPE (t1);
 511   mv2 = pointed_to_2 = TREE_TYPE (t2);
 512   if (TREE_CODE (mv1) != ARRAY_TYPE)
 513     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 514   if (TREE_CODE (mv2) != ARRAY_TYPE)
 515     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 516   target = composite_type (mv1, mv2);
 517   t1 = build_pointer_type (c_build_qualified_type
 518                            (target,
 519                             TYPE_QUALS (pointed_to_1) |
 520                             TYPE_QUALS (pointed_to_2)));
 521   return build_type_attribute_variant (t1, attributes);
 522 }
 523
 524 /* Return the common type for two arithmetic types under the usual
 525    arithmetic conversions.  The default conversions have already been
 526    applied, and enumerated types converted to their compatible integer
 527    types.  The resulting type is unqualified and has no attributes.
 528
 529    This is the type for the result of most arithmetic operations
 530    if the operands have the given two types.  */
 531
 532 static tree
 533 c_common_type (tree t1, tree t2)
 534 {
 535   enum tree_code code1;
 536   enum tree_code code2;
 537
 538   /* If one type is nonsense, use the other.  */
 539   if (t1 == error_mark_node)
 540     return t2;
 541   if (t2 == error_mark_node)
 542     return t1;
 543
 544   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 545     t1 = TYPE_MAIN_VARIANT (t1);
 546
 547   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 548     t2 = TYPE_MAIN_VARIANT (t2);
 549
 550   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 551     t1 = build_type_attribute_variant (t1, NULL_TREE);
 552
 553   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 554     t2 = build_type_attribute_variant (t2, NULL_TREE);
 555
 556   /* Save time if the two types are the same.  */
 557
 558   if (t1 == t2) return t1;
 559
 560   code1 = TREE_CODE (t1);
 561   code2 = TREE_CODE (t2);
 562
 563   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 564               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 565   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 566               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 567
 568   /* If one type is a vector type, return that type.  (How the usual
 569      arithmetic conversions apply to the vector types extension is not
 570      precisely specified.)  */
 571   if (code1 == VECTOR_TYPE)
 572     return t1;
 573
 574   if (code2 == VECTOR_TYPE)
 575     return t2;
 576
 577   /* If one type is complex, form the common type of the non-complex
 578      components, then make that complex.  Use T1 or T2 if it is the
 579      required type.  */
 580   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 581     {
 582       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 583       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 584       tree subtype = c_common_type (subtype1, subtype2);
 585
 586       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 587         return t1;
 588       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 589         return t2;
 590       else
 591         return build_complex_type (subtype);
 592     }
 593
 594   /* If only one is real, use it as the result.  */
 595
 596   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 597     return t1;
 598
 599   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 600     return t2;
 601
 602   /* Both real or both integers; use the one with greater precision.  */
 603
 604   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 605     return t1;
 606   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 607     return t2;
 608
 609   /* Same precision.  Prefer long longs to longs to ints when the
 610      same precision, following the C99 rules on integer type rank
 611      (which are equivalent to the C90 rules for C90 types).  */
 612
 613   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 614       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 615     return long_long_unsigned_type_node;
 616
 617   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 618       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 619     {
 620       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 621         return long_long_unsigned_type_node;
 622       else
 623         return long_long_integer_type_node;
 624     }
 625
 626   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 627       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 628     return long_unsigned_type_node;
 629
 630   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 631       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 632     {
 633       /* But preserve unsignedness from the other type,
 634          since long cannot hold all the values of an unsigned int.  */
 635       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 636         return long_unsigned_type_node;
 637       else
 638         return long_integer_type_node;
 639     }
 640
 641   /* Likewise, prefer long double to double even if same size.  */
 642   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 643       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 644     return long_double_type_node;
 645
 646   /* Otherwise prefer the unsigned one.  */
 647
 648   if (TYPE_UNSIGNED (t1))
 649     return t1;
 650   else
 651     return t2;
 652 }
 653 \f
 654 /* Wrapper around c_common_type that is used by c-common.c and other
 655    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 656    are allowed here and are converted to their compatible integer types.
 657    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 658    preferably a non-Boolean type as the common type.  */
 659 tree
 660 common_type (tree t1, tree t2)
 661 {
 662   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 663     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 664   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 665     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 666
 667   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 668   if (TREE_CODE (t1) == BOOLEAN_TYPE
 669       && TREE_CODE (t2) == BOOLEAN_TYPE)
 670     return boolean_type_node;
 671
 672   /* If either type is BOOLEAN_TYPE, then return the other.  */
 673   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 674     return t2;
 675   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 676     return t1;
 677
 678   return c_common_type (t1, t2);
 679 }
 680
 681 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 682    or various other operations.  Return 2 if they are compatible
 683    but a warning may be needed if you use them together.  */
 684
 685 int
 686 comptypes (tree type1, tree type2)
 687 {
 688   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 689   int val;
 690
 691   val = comptypes_internal (type1, type2);
 692   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 693
 694   return val;
 695 }\f
 696 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 697    or various other operations.  Return 2 if they are compatible
 698    but a warning may be needed if you use them together.  This
 699    differs from comptypes, in that we don't free the seen types.  */
 700
 701 static int
 702 comptypes_internal (tree type1, tree type2)
 703 {
 704   tree t1 = type1;
 705   tree t2 = type2;
 706   int attrval, val;
 707
 708   /* Suppress errors caused by previously reported errors.  */
 709
 710   if (t1 == t2 || !t1 || !t2
 711       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 712     return 1;
 713
 714   /* If either type is the internal version of sizetype, return the
 715      language version.  */
 716   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 717       && TYPE_ORIG_SIZE_TYPE (t1))
 718     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 719
 720   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 721       && TYPE_ORIG_SIZE_TYPE (t2))
 722     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 723
 724
 725   /* Enumerated types are compatible with integer types, but this is
 726      not transitive: two enumerated types in the same translation unit
 727      are compatible with each other only if they are the same type.  */
 728
 729   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 730     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 731   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 732     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 733
 734   if (t1 == t2)
 735     return 1;
 736
 737   /* Different classes of types can't be compatible.  */
 738
 739   if (TREE_CODE (t1) != TREE_CODE (t2))
 740     return 0;
 741
 742   /* Qualifiers must match. C99 6.7.3p9 */
 743
 744   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 745     return 0;
 746
 747   /* Allow for two different type nodes which have essentially the same
 748      definition.  Note that we already checked for equality of the type
 749      qualifiers (just above).  */
 750
 751   if (TREE_CODE (t1) != ARRAY_TYPE
 752       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 753     return 1;
 754
 755   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 756   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 757      return 0;
 758
 759   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 760   val = 0;
 761
 762   switch (TREE_CODE (t1))
 763     {
 764     case POINTER_TYPE:
 765       /* Do not remove mode or aliasing information.  */
 766       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 767           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 768         break;
 769       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 770              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 771       break;
 772
 773     case FUNCTION_TYPE:
 774       val = function_types_compatible_p (t1, t2);
 775       break;
 776
 777     case ARRAY_TYPE:
 778       {
 779         tree d1 = TYPE_DOMAIN (t1);
 780         tree d2 = TYPE_DOMAIN (t2);
 781         bool d1_variable, d2_variable;
 782         bool d1_zero, d2_zero;
 783         val = 1;
 784
 785         /* Target types must match incl. qualifiers.  */
 786         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 787             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 788           return 0;
 789
 790         /* Sizes must match unless one is missing or variable.  */
 791         if (d1 == 0 || d2 == 0 || d1 == d2)
 792           break;
 793
 794         d1_zero = !TYPE_MAX_VALUE (d1);
 795         d2_zero = !TYPE_MAX_VALUE (d2);
 796
 797         d1_variable = (!d1_zero
 798                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 799                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 800         d2_variable = (!d2_zero
 801                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 802                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 803
 804         if (d1_variable || d2_variable)
 805           break;
 806         if (d1_zero && d2_zero)
 807           break;
 808         if (d1_zero || d2_zero
 809             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 810             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 811           val = 0;
 812
 813         break;
 814       }
 815
 816     case ENUMERAL_TYPE:
 817     case RECORD_TYPE:
 818     case UNION_TYPE:
 819       if (val != 1 && !same_translation_unit_p (t1, t2))
 820         {
 821           if (attrval != 2)
 822             return tagged_types_tu_compatible_p (t1, t2);
 823           val = tagged_types_tu_compatible_p (t1, t2);
 824         }
 825       break;
 826
 827     case VECTOR_TYPE:
 828       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 829             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
 830       break;
 831
 832     default:
 833       break;
 834     }
 835   return attrval == 2 && val == 1 ? 2 : val;
 836 }
 837
 838 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 839    ignoring their qualifiers.  */
 840
 841 static int
 842 comp_target_types (tree ttl, tree ttr)
 843 {
 844   int val;
 845   tree mvl, mvr;
 846
 847   /* Do not lose qualifiers on element types of array types that are
 848      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 849   mvl = TREE_TYPE (ttl);
 850   mvr = TREE_TYPE (ttr);
 851   if (TREE_CODE (mvl) != ARRAY_TYPE)
 852     mvl = TYPE_MAIN_VARIANT (mvl);
 853   if (TREE_CODE (mvr) != ARRAY_TYPE)
 854     mvr = TYPE_MAIN_VARIANT (mvr);
 855   val = comptypes (mvl, mvr);
 856
 857   if (val == 2 && pedantic)
 858     pedwarn ("types are not quite compatible");
 859   return val;
 860 }
 861 \f
 862 /* Subroutines of `comptypes'.  */
 863
 864 /* Determine whether two trees derive from the same translation unit.
 865    If the CONTEXT chain ends in a null, that tree's context is still
 866    being parsed, so if two trees have context chains ending in null,
 867    they're in the same translation unit.  */
 868 int
 869 same_translation_unit_p (tree t1, tree t2)
 870 {
 871   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 872     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 873       {
 874       case tcc_declaration:
 875         t1 = DECL_CONTEXT (t1); break;
 876       case tcc_type:
 877         t1 = TYPE_CONTEXT (t1); break;
 878       case tcc_exceptional:
 879         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 880       default: gcc_unreachable ();
 881       }
 882
 883   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 884     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 885       {
 886       case tcc_declaration:
 887         t2 = DECL_CONTEXT (t2); break;
 888       case tcc_type:
 889         t2 = TYPE_CONTEXT (t2); break;
 890       case tcc_exceptional:
 891         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 892       default: gcc_unreachable ();
 893       }
 894
 895   return t1 == t2;
 896 }
 897
 898 /* Allocate the seen two types, assuming that they are compatible. */
 899
 900 static struct tagged_tu_seen_cache *
 901 alloc_tagged_tu_seen_cache (tree t1, tree t2)
 902 {
 903   struct tagged_tu_seen_cache *tu = xmalloc (sizeof (struct tagged_tu_seen_cache));
 904   tu->next = tagged_tu_seen_base;
 905   tu->t1 = t1;
 906   tu->t2 = t2;
 907
 908   tagged_tu_seen_base = tu;
 909
 910   /* The C standard says that two structures in different translation
 911      units are compatible with each other only if the types of their
 912      fields are compatible (among other things).  We assume that they
 913      are compatible until proven otherwise when building the cache.
 914      An example where this can occur is:
 915      struct a
 916      {
 917        struct a *next;
 918      };
 919      If we are comparing this against a similar struct in another TU,
 920      and did not assume they were compatible, we end up with an infinite
 921      loop.  */
 922   tu->val = 1;
 923   return tu;
 924 }
 925
 926 /* Free the seen types until we get to TU_TIL. */
 927
 928 static void
 929 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
 930 {
 931   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
 932   while (tu != tu_til)
 933     {
 934       struct tagged_tu_seen_cache *tu1 = (struct tagged_tu_seen_cache*)tu;
 935       tu = tu1->next;
 936       free (tu1);
 937     }
 938   tagged_tu_seen_base = tu_til;
 939 }
 940
 941 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 942    compatible.  If the two types are not the same (which has been
 943    checked earlier), this can only happen when multiple translation
 944    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 945    rules.  */
 946
 947 static int
 948 tagged_types_tu_compatible_p (tree t1, tree t2)
 949 {
 950   tree s1, s2;
 951   bool needs_warning = false;
 952
 953   /* We have to verify that the tags of the types are the same.  This
 954      is harder than it looks because this may be a typedef, so we have
 955      to go look at the original type.  It may even be a typedef of a
 956      typedef...
 957      In the case of compiler-created builtin structs the TYPE_DECL
 958      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 959   while (TYPE_NAME (t1)
 960          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 961          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 962     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 963
 964   while (TYPE_NAME (t2)
 965          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 966          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 967     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 968
 969   /* C90 didn't have the requirement that the two tags be the same.  */
 970   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 971     return 0;
 972
 973   /* C90 didn't say what happened if one or both of the types were
 974      incomplete; we choose to follow C99 rules here, which is that they
 975      are compatible.  */
 976   if (TYPE_SIZE (t1) == NULL
 977       || TYPE_SIZE (t2) == NULL)
 978     return 1;
 979
 980   {
 981     const struct tagged_tu_seen_cache * tts_i;
 982     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 983       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 984         return tts_i->val;
 985   }
 986
 987   switch (TREE_CODE (t1))
 988     {
 989     case ENUMERAL_TYPE:
 990       {
 991         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
 992         /* Speed up the case where the type values are in the same order.  */
 993         tree tv1 = TYPE_VALUES (t1);
 994         tree tv2 = TYPE_VALUES (t2);
 995
 996         if (tv1 == tv2)
 997           {
 998             return 1;
 999           }
1000
1001         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1002           {
1003             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1004               break;
1005             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1006               {
1007                 tu->val = 0;
1008                 return 0;
1009               }
1010           }
1011
1012         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1013           {
1014             return 1;
1015           }
1016         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1017           {
1018             tu->val = 0;
1019             return 0;
1020           }
1021
1022         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1023           {
1024             tu->val = 0;
1025             return 0;
1026           }
1027
1028         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1029           {
1030             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1031             if (s2 == NULL
1032                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1033               {
1034                 tu->val = 0;
1035                 return 0;
1036               }
1037           }
1038         return 1;
1039       }
1040
1041     case UNION_TYPE:
1042       {
1043         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1044         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1045           {
1046             tu->val = 0;
1047             return 0;
1048           }
1049
1050         /*  Speed up the common case where the fields are in the same order. */
1051         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1052              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1053           {
1054             int result;
1055
1056
1057             if (DECL_NAME (s1) == NULL
1058                 || DECL_NAME (s1) != DECL_NAME (s2))
1059               break;
1060             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1061             if (result == 0)
1062               {
1063                 tu->val = 0;
1064                 return 0;
1065               }
1066             if (result == 2)
1067               needs_warning = true;
1068
1069             if (TREE_CODE (s1) == FIELD_DECL
1070                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1071                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1072               {
1073                 tu->val = 0;
1074                 return 0;
1075               }
1076           }
1077         if (!s1 && !s2)
1078           {
1079             tu->val = needs_warning ? 2 : 1;
1080             return tu->val;
1081           }
1082
1083         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1084           {
1085             bool ok = false;
1086
1087             if (DECL_NAME (s1) != NULL)
1088               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1089                 if (DECL_NAME (s1) == DECL_NAME (s2))
1090                   {
1091                     int result;
1092                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1093                     if (result == 0)
1094                       {
1095                         tu->val = 0;
1096                         return 0;
1097                       }
1098                     if (result == 2)
1099                       needs_warning = true;
1100
1101                     if (TREE_CODE (s1) == FIELD_DECL
1102                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1103                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1104                       break;
1105
1106                     ok = true;
1107                     break;
1108                   }
1109             if (!ok)
1110               {
1111                 tu->val = 0;
1112                 return 0;
1113               }
1114           }
1115         tu->val = needs_warning ? 2 : 10;
1116         return tu->val;
1117       }
1118
1119     case RECORD_TYPE:
1120       {
1121         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1122
1123         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1124              s1 && s2;
1125              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1126           {
1127             int result;
1128             if (TREE_CODE (s1) != TREE_CODE (s2)
1129                 || DECL_NAME (s1) != DECL_NAME (s2))
1130               break;
1131             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1132             if (result == 0)
1133               break;
1134             if (result == 2)
1135               needs_warning = true;
1136
1137             if (TREE_CODE (s1) == FIELD_DECL
1138                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1139                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1140               break;
1141           }
1142         if (s1 && s2)
1143           tu->val = 0;
1144         else
1145           tu->val = needs_warning ? 2 : 1;
1146         return tu->val;
1147       }
1148
1149     default:
1150       gcc_unreachable ();
1151     }
1152 }
1153
1154 /* Return 1 if two function types F1 and F2 are compatible.
1155    If either type specifies no argument types,
1156    the other must specify a fixed number of self-promoting arg types.
1157    Otherwise, if one type specifies only the number of arguments,
1158    the other must specify that number of self-promoting arg types.
1159    Otherwise, the argument types must match.  */
1160
1161 static int
1162 function_types_compatible_p (tree f1, tree f2)
1163 {
1164   tree args1, args2;
1165   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1166   int val = 1;
1167   int val1;
1168   tree ret1, ret2;
1169
1170   ret1 = TREE_TYPE (f1);
1171   ret2 = TREE_TYPE (f2);
1172
1173   /* 'volatile' qualifiers on a function's return type used to mean
1174      the function is noreturn.  */
1175   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1176     pedwarn ("function return types not compatible due to %<volatile%>");
1177   if (TYPE_VOLATILE (ret1))
1178     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1179                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1180   if (TYPE_VOLATILE (ret2))
1181     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1182                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1183   val = comptypes_internal (ret1, ret2);
1184   if (val == 0)
1185     return 0;
1186
1187   args1 = TYPE_ARG_TYPES (f1);
1188   args2 = TYPE_ARG_TYPES (f2);
1189
1190   /* An unspecified parmlist matches any specified parmlist
1191      whose argument types don't need default promotions.  */
1192
1193   if (args1 == 0)
1194     {
1195       if (!self_promoting_args_p (args2))
1196         return 0;
1197       /* If one of these types comes from a non-prototype fn definition,
1198          compare that with the other type's arglist.
1199          If they don't match, ask for a warning (but no error).  */
1200       if (TYPE_ACTUAL_ARG_TYPES (f1)
1201           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1202         val = 2;
1203       return val;
1204     }
1205   if (args2 == 0)
1206     {
1207       if (!self_promoting_args_p (args1))
1208         return 0;
1209       if (TYPE_ACTUAL_ARG_TYPES (f2)
1210           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1211         val = 2;
1212       return val;
1213     }
1214
1215   /* Both types have argument lists: compare them and propagate results.  */
1216   val1 = type_lists_compatible_p (args1, args2);
1217   return val1 != 1 ? val1 : val;
1218 }
1219
1220 /* Check two lists of types for compatibility,
1221    returning 0 for incompatible, 1 for compatible,
1222    or 2 for compatible with warning.  */
1223
1224 static int
1225 type_lists_compatible_p (tree args1, tree args2)
1226 {
1227   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1228   int val = 1;
1229   int newval = 0;
1230
1231   while (1)
1232     {
1233       tree a1, mv1, a2, mv2;
1234       if (args1 == 0 && args2 == 0)
1235         return val;
1236       /* If one list is shorter than the other,
1237          they fail to match.  */
1238       if (args1 == 0 || args2 == 0)
1239         return 0;
1240       mv1 = a1 = TREE_VALUE (args1);
1241       mv2 = a2 = TREE_VALUE (args2);
1242       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1243         mv1 = TYPE_MAIN_VARIANT (mv1);
1244       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1245         mv2 = TYPE_MAIN_VARIANT (mv2);
1246       /* A null pointer instead of a type
1247          means there is supposed to be an argument
1248          but nothing is specified about what type it has.
1249          So match anything that self-promotes.  */
1250       if (a1 == 0)
1251         {
1252           if (c_type_promotes_to (a2) != a2)
1253             return 0;
1254         }
1255       else if (a2 == 0)
1256         {
1257           if (c_type_promotes_to (a1) != a1)
1258             return 0;
1259         }
1260       /* If one of the lists has an error marker, ignore this arg.  */
1261       else if (TREE_CODE (a1) == ERROR_MARK
1262                || TREE_CODE (a2) == ERROR_MARK)
1263         ;
1264       else if (!(newval = comptypes_internal (mv1, mv2)))
1265         {
1266           /* Allow  wait (union {union wait *u; int *i} *)
1267              and  wait (union wait *)  to be compatible.  */
1268           if (TREE_CODE (a1) == UNION_TYPE
1269               && (TYPE_NAME (a1) == 0
1270                   || TYPE_TRANSPARENT_UNION (a1))
1271               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1272               && tree_int_cst_equal (TYPE_SIZE (a1),
1273                                      TYPE_SIZE (a2)))
1274             {
1275               tree memb;
1276               for (memb = TYPE_FIELDS (a1);
1277                    memb; memb = TREE_CHAIN (memb))
1278                 {
1279                   tree mv3 = TREE_TYPE (memb);
1280                   if (mv3 && mv3 != error_mark_node
1281                       && TREE_CODE (mv3) != ARRAY_TYPE)
1282                     mv3 = TYPE_MAIN_VARIANT (mv3);
1283                   if (comptypes_internal (mv3, mv2))
1284                     break;
1285                 }
1286               if (memb == 0)
1287                 return 0;
1288             }
1289           else if (TREE_CODE (a2) == UNION_TYPE
1290                    && (TYPE_NAME (a2) == 0
1291                        || TYPE_TRANSPARENT_UNION (a2))
1292                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1293                    && tree_int_cst_equal (TYPE_SIZE (a2),
1294                                           TYPE_SIZE (a1)))
1295             {
1296               tree memb;
1297               for (memb = TYPE_FIELDS (a2);
1298                    memb; memb = TREE_CHAIN (memb))
1299                 {
1300                   tree mv3 = TREE_TYPE (memb);
1301                   if (mv3 && mv3 != error_mark_node
1302                       && TREE_CODE (mv3) != ARRAY_TYPE)
1303                     mv3 = TYPE_MAIN_VARIANT (mv3);
1304                   if (comptypes_internal (mv3, mv1))
1305                     break;
1306                 }
1307               if (memb == 0)
1308                 return 0;
1309             }
1310           else
1311             return 0;
1312         }
1313
1314       /* comptypes said ok, but record if it said to warn.  */
1315       if (newval > val)
1316         val = newval;
1317
1318       args1 = TREE_CHAIN (args1);
1319       args2 = TREE_CHAIN (args2);
1320     }
1321 }
1322 \f
1323 /* Compute the size to increment a pointer by.  */
1324
1325 static tree
1326 c_size_in_bytes (tree type)
1327 {
1328   enum tree_code code = TREE_CODE (type);
1329
1330   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1331     return size_one_node;
1332
1333   if (!COMPLETE_OR_VOID_TYPE_P (type))
1334     {
1335       error ("arithmetic on pointer to an incomplete type");
1336       return size_one_node;
1337     }
1338
1339   /* Convert in case a char is more than one unit.  */
1340   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1341                      size_int (TYPE_PRECISION (char_type_node)
1342                                / BITS_PER_UNIT));
1343 }
1344 \f
1345 /* Return either DECL or its known constant value (if it has one).  */
1346
1347 tree
1348 decl_constant_value (tree decl)
1349 {
1350   if (/* Don't change a variable array bound or initial value to a constant
1351          in a place where a variable is invalid.  Note that DECL_INITIAL
1352          isn't valid for a PARM_DECL.  */
1353       current_function_decl != 0
1354       && TREE_CODE (decl) != PARM_DECL
1355       && !TREE_THIS_VOLATILE (decl)
1356       && TREE_READONLY (decl)
1357       && DECL_INITIAL (decl) != 0
1358       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1359       /* This is invalid if initial value is not constant.
1360          If it has either a function call, a memory reference,
1361          or a variable, then re-evaluating it could give different results.  */
1362       && TREE_CONSTANT (DECL_INITIAL (decl))
1363       /* Check for cases where this is sub-optimal, even though valid.  */
1364       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1365     return DECL_INITIAL (decl);
1366   return decl;
1367 }
1368
1369 /* Return either DECL or its known constant value (if it has one), but
1370    return DECL if pedantic or DECL has mode BLKmode.  This is for
1371    bug-compatibility with the old behavior of decl_constant_value
1372    (before GCC 3.0); every use of this function is a bug and it should
1373    be removed before GCC 3.1.  It is not appropriate to use pedantic
1374    in a way that affects optimization, and BLKmode is probably not the
1375    right test for avoiding misoptimizations either.  */
1376
1377 static tree
1378 decl_constant_value_for_broken_optimization (tree decl)
1379 {
1380   tree ret;
1381
1382   if (pedantic || DECL_MODE (decl) == BLKmode)
1383     return decl;
1384
1385   ret = decl_constant_value (decl);
1386   /* Avoid unwanted tree sharing between the initializer and current
1387      function's body where the tree can be modified e.g. by the
1388      gimplifier.  */
1389   if (ret != decl && TREE_STATIC (decl))
1390     ret = unshare_expr (ret);
1391   return ret;
1392 }
1393
1394 /* Convert the array expression EXP to a pointer.  */
1395 static tree
1396 array_to_pointer_conversion (tree exp)
1397 {
1398   tree orig_exp = exp;
1399   tree type = TREE_TYPE (exp);
1400   tree adr;
1401   tree restype = TREE_TYPE (type);
1402   tree ptrtype;
1403
1404   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1405
1406   STRIP_TYPE_NOPS (exp);
1407
1408   if (TREE_NO_WARNING (orig_exp))
1409     TREE_NO_WARNING (exp) = 1;
1410
1411   ptrtype = build_pointer_type (restype);
1412
1413   if (TREE_CODE (exp) == INDIRECT_REF)
1414     return convert (ptrtype, TREE_OPERAND (exp, 0));
1415
1416   if (TREE_CODE (exp) == VAR_DECL)
1417     {
1418       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1419          ADDR_EXPR because it's the best way of representing what
1420          happens in C when we take the address of an array and place
1421          it in a pointer to the element type.  */
1422       adr = build1 (ADDR_EXPR, ptrtype, exp);
1423       if (!c_mark_addressable (exp))
1424         return error_mark_node;
1425       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1426       return adr;
1427     }
1428
1429   /* This way is better for a COMPONENT_REF since it can
1430      simplify the offset for a component.  */
1431   adr = build_unary_op (ADDR_EXPR, exp, 1);
1432   return convert (ptrtype, adr);
1433 }
1434
1435 /* Convert the function expression EXP to a pointer.  */
1436 static tree
1437 function_to_pointer_conversion (tree exp)
1438 {
1439   tree orig_exp = exp;
1440
1441   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1442
1443   STRIP_TYPE_NOPS (exp);
1444
1445   if (TREE_NO_WARNING (orig_exp))
1446     TREE_NO_WARNING (exp) = 1;
1447
1448   return build_unary_op (ADDR_EXPR, exp, 0);
1449 }
1450
1451 /* Perform the default conversion of arrays and functions to pointers.
1452    Return the result of converting EXP.  For any other expression, just
1453    return EXP after removing NOPs.  */
1454
1455 struct c_expr
1456 default_function_array_conversion (struct c_expr exp)
1457 {
1458   tree orig_exp = exp.value;
1459   tree type = TREE_TYPE (exp.value);
1460   enum tree_code code = TREE_CODE (type);
1461
1462   switch (code)
1463     {
1464     case ARRAY_TYPE:
1465       {
1466         bool not_lvalue = false;
1467         bool lvalue_array_p;
1468
1469         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1470                 || TREE_CODE (exp.value) == NOP_EXPR)
1471                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1472           {
1473             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1474               not_lvalue = true;
1475             exp.value = TREE_OPERAND (exp.value, 0);
1476           }
1477
1478         if (TREE_NO_WARNING (orig_exp))
1479           TREE_NO_WARNING (exp.value) = 1;
1480
1481         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1482         if (!flag_isoc99 && !lvalue_array_p)
1483           {
1484             /* Before C99, non-lvalue arrays do not decay to pointers.
1485                Normally, using such an array would be invalid; but it can
1486                be used correctly inside sizeof or as a statement expression.
1487                Thus, do not give an error here; an error will result later.  */
1488             return exp;
1489           }
1490
1491         exp.value = array_to_pointer_conversion (exp.value);
1492       }
1493       break;
1494     case FUNCTION_TYPE:
1495       exp.value = function_to_pointer_conversion (exp.value);
1496       break;
1497     default:
1498       STRIP_TYPE_NOPS (exp.value);
1499       if (TREE_NO_WARNING (orig_exp))
1500         TREE_NO_WARNING (exp.value) = 1;
1501       break;
1502     }
1503
1504   return exp;
1505 }
1506
1507
1508 /* EXP is an expression of integer type.  Apply the integer promotions
1509    to it and return the promoted value.  */
1510
1511 tree
1512 perform_integral_promotions (tree exp)
1513 {
1514   tree type = TREE_TYPE (exp);
1515   enum tree_code code = TREE_CODE (type);
1516
1517   gcc_assert (INTEGRAL_TYPE_P (type));
1518
1519   /* Normally convert enums to int,
1520      but convert wide enums to something wider.  */
1521   if (code == ENUMERAL_TYPE)
1522     {
1523       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1524                                           TYPE_PRECISION (integer_type_node)),
1525                                      ((TYPE_PRECISION (type)
1526                                        >= TYPE_PRECISION (integer_type_node))
1527                                       && TYPE_UNSIGNED (type)));
1528
1529       return convert (type, exp);
1530     }
1531
1532   /* ??? This should no longer be needed now bit-fields have their
1533      proper types.  */
1534   if (TREE_CODE (exp) == COMPONENT_REF
1535       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1536       /* If it's thinner than an int, promote it like a
1537          c_promoting_integer_type_p, otherwise leave it alone.  */
1538       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1539                                TYPE_PRECISION (integer_type_node)))
1540     return convert (integer_type_node, exp);
1541
1542   if (c_promoting_integer_type_p (type))
1543     {
1544       /* Preserve unsignedness if not really getting any wider.  */
1545       if (TYPE_UNSIGNED (type)
1546           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1547         return convert (unsigned_type_node, exp);
1548
1549       return convert (integer_type_node, exp);
1550     }
1551
1552   return exp;
1553 }
1554
1555
1556 /* Perform default promotions for C data used in expressions.
1557    Enumeral types or short or char are converted to int.
1558    In addition, manifest constants symbols are replaced by their values.  */
1559
1560 tree
1561 default_conversion (tree exp)
1562 {
1563   tree orig_exp;
1564   tree type = TREE_TYPE (exp);
1565   enum tree_code code = TREE_CODE (type);
1566
1567   /* Functions and arrays have been converted during parsing.  */
1568   gcc_assert (code != FUNCTION_TYPE);
1569   if (code == ARRAY_TYPE)
1570     return exp;
1571
1572   /* Constants can be used directly unless they're not loadable.  */
1573   if (TREE_CODE (exp) == CONST_DECL)
1574     exp = DECL_INITIAL (exp);
1575
1576   /* Replace a nonvolatile const static variable with its value unless
1577      it is an array, in which case we must be sure that taking the
1578      address of the array produces consistent results.  */
1579   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1580     {
1581       exp = decl_constant_value_for_broken_optimization (exp);
1582       type = TREE_TYPE (exp);
1583     }
1584
1585   /* Strip no-op conversions.  */
1586   orig_exp = exp;
1587   STRIP_TYPE_NOPS (exp);
1588
1589   if (TREE_NO_WARNING (orig_exp))
1590     TREE_NO_WARNING (exp) = 1;
1591
1592   if (INTEGRAL_TYPE_P (type))
1593     return perform_integral_promotions (exp);
1594
1595   if (code == VOID_TYPE)
1596     {
1597       error ("void value not ignored as it ought to be");
1598       return error_mark_node;
1599     }
1600   return exp;
1601 }
1602 \f
1603 /* Look up COMPONENT in a structure or union DECL.
1604
1605    If the component name is not found, returns NULL_TREE.  Otherwise,
1606    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1607    stepping down the chain to the component, which is in the last
1608    TREE_VALUE of the list.  Normally the list is of length one, but if
1609    the component is embedded within (nested) anonymous structures or
1610    unions, the list steps down the chain to the component.  */
1611
1612 static tree
1613 lookup_field (tree decl, tree component)
1614 {
1615   tree type = TREE_TYPE (decl);
1616   tree field;
1617
1618   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1619      to the field elements.  Use a binary search on this array to quickly
1620      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1621      will always be set for structures which have many elements.  */
1622
1623   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1624     {
1625       int bot, top, half;
1626       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1627
1628       field = TYPE_FIELDS (type);
1629       bot = 0;
1630       top = TYPE_LANG_SPECIFIC (type)->s->len;
1631       while (top - bot > 1)
1632         {
1633           half = (top - bot + 1) >> 1;
1634           field = field_array[bot+half];
1635
1636           if (DECL_NAME (field) == NULL_TREE)
1637             {
1638               /* Step through all anon unions in linear fashion.  */
1639               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1640                 {
1641                   field = field_array[bot++];
1642                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1643                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1644                     {
1645                       tree anon = lookup_field (field, component);
1646
1647                       if (anon)
1648                         return tree_cons (NULL_TREE, field, anon);
1649                     }
1650                 }
1651
1652               /* Entire record is only anon unions.  */
1653               if (bot > top)
1654                 return NULL_TREE;
1655
1656               /* Restart the binary search, with new lower bound.  */
1657               continue;
1658             }
1659
1660           if (DECL_NAME (field) == component)
1661             break;
1662           if (DECL_NAME (field) < component)
1663             bot += half;
1664           else
1665             top = bot + half;
1666         }
1667
1668       if (DECL_NAME (field_array[bot]) == component)
1669         field = field_array[bot];
1670       else if (DECL_NAME (field) != component)
1671         return NULL_TREE;
1672     }
1673   else
1674     {
1675       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1676         {
1677           if (DECL_NAME (field) == NULL_TREE
1678               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1679                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1680             {
1681               tree anon = lookup_field (field, component);
1682
1683               if (anon)
1684                 return tree_cons (NULL_TREE, field, anon);
1685             }
1686
1687           if (DECL_NAME (field) == component)
1688             break;
1689         }
1690
1691       if (field == NULL_TREE)
1692         return NULL_TREE;
1693     }
1694
1695   return tree_cons (NULL_TREE, field, NULL_TREE);
1696 }
1697
1698 /* Make an expression to refer to the COMPONENT field of
1699    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1700
1701 tree
1702 build_component_ref (tree datum, tree component)
1703 {
1704   tree type = TREE_TYPE (datum);
1705   enum tree_code code = TREE_CODE (type);
1706   tree field = NULL;
1707   tree ref;
1708
1709   if (!objc_is_public (datum, component))
1710     return error_mark_node;
1711
1712   /* See if there is a field or component with name COMPONENT.  */
1713
1714   if (code == RECORD_TYPE || code == UNION_TYPE)
1715     {
1716       if (!COMPLETE_TYPE_P (type))
1717         {
1718           c_incomplete_type_error (NULL_TREE, type);
1719           return error_mark_node;
1720         }
1721
1722       field = lookup_field (datum, component);
1723
1724       if (!field)
1725         {
1726           error ("%qT has no member named %qE", type, component);
1727           return error_mark_node;
1728         }
1729
1730       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1731          This might be better solved in future the way the C++ front
1732          end does it - by giving the anonymous entities each a
1733          separate name and type, and then have build_component_ref
1734          recursively call itself.  We can't do that here.  */
1735       do
1736         {
1737           tree subdatum = TREE_VALUE (field);
1738
1739           if (TREE_TYPE (subdatum) == error_mark_node)
1740             return error_mark_node;
1741
1742           ref = build3 (COMPONENT_REF, TREE_TYPE (subdatum), datum, subdatum,
1743                         NULL_TREE);
1744           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1745             TREE_READONLY (ref) = 1;
1746           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1747             TREE_THIS_VOLATILE (ref) = 1;
1748
1749           if (TREE_DEPRECATED (subdatum))
1750             warn_deprecated_use (subdatum);
1751
1752           datum = ref;
1753
1754           field = TREE_CHAIN (field);
1755         }
1756       while (field);
1757
1758       return ref;
1759     }
1760   else if (code != ERROR_MARK)
1761     error ("request for member %qE in something not a structure or union",
1762            component);
1763
1764   return error_mark_node;
1765 }
1766 \f
1767 /* Given an expression PTR for a pointer, return an expression
1768    for the value pointed to.
1769    ERRORSTRING is the name of the operator to appear in error messages.  */
1770
1771 tree
1772 build_indirect_ref (tree ptr, const char *errorstring)
1773 {
1774   tree pointer = default_conversion (ptr);
1775   tree type = TREE_TYPE (pointer);
1776
1777   if (TREE_CODE (type) == POINTER_TYPE)
1778     {
1779       if (TREE_CODE (pointer) == ADDR_EXPR
1780           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1781               == TREE_TYPE (type)))
1782         return TREE_OPERAND (pointer, 0);
1783       else
1784         {
1785           tree t = TREE_TYPE (type);
1786           tree ref;
1787
1788           ref = build1 (INDIRECT_REF, t, pointer);
1789
1790           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1791             {
1792               error ("dereferencing pointer to incomplete type");
1793               return error_mark_node;
1794             }
1795           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1796             warning (0, "dereferencing %<void *%> pointer");
1797
1798           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1799              so that we get the proper error message if the result is used
1800              to assign to.  Also, &* is supposed to be a no-op.
1801              And ANSI C seems to specify that the type of the result
1802              should be the const type.  */
1803           /* A de-reference of a pointer to const is not a const.  It is valid
1804              to change it via some other pointer.  */
1805           TREE_READONLY (ref) = TYPE_READONLY (t);
1806           TREE_SIDE_EFFECTS (ref)
1807             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1808           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1809           return ref;
1810         }
1811     }
1812   else if (TREE_CODE (pointer) != ERROR_MARK)
1813     error ("invalid type argument of %qs", errorstring);
1814   return error_mark_node;
1815 }
1816
1817 /* This handles expressions of the form "a[i]", which denotes
1818    an array reference.
1819
1820    This is logically equivalent in C to *(a+i), but we may do it differently.
1821    If A is a variable or a member, we generate a primitive ARRAY_REF.
1822    This avoids forcing the array out of registers, and can work on
1823    arrays that are not lvalues (for example, members of structures returned
1824    by functions).  */
1825
1826 tree
1827 build_array_ref (tree array, tree index)
1828 {
1829   bool swapped = false;
1830   if (TREE_TYPE (array) == error_mark_node
1831       || TREE_TYPE (index) == error_mark_node)
1832     return error_mark_node;
1833
1834   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1835       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1836     {
1837       tree temp;
1838       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1839           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1840         {
1841           error ("subscripted value is neither array nor pointer");
1842           return error_mark_node;
1843         }
1844       temp = array;
1845       array = index;
1846       index = temp;
1847       swapped = true;
1848     }
1849
1850   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1851     {
1852       error ("array subscript is not an integer");
1853       return error_mark_node;
1854     }
1855
1856   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1857     {
1858       error ("subscripted value is pointer to function");
1859       return error_mark_node;
1860     }
1861
1862   /* ??? Existing practice has been to warn only when the char
1863      index is syntactically the index, not for char[array].  */
1864   if (!swapped)
1865      warn_array_subscript_with_type_char (index);
1866
1867   /* Apply default promotions *after* noticing character types.  */
1868   index = default_conversion (index);
1869
1870   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1871
1872   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1873     {
1874       tree rval, type;
1875
1876       /* An array that is indexed by a non-constant
1877          cannot be stored in a register; we must be able to do
1878          address arithmetic on its address.
1879          Likewise an array of elements of variable size.  */
1880       if (TREE_CODE (index) != INTEGER_CST
1881           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1882               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1883         {
1884           if (!c_mark_addressable (array))
1885             return error_mark_node;
1886         }
1887       /* An array that is indexed by a constant value which is not within
1888          the array bounds cannot be stored in a register either; because we
1889          would get a crash in store_bit_field/extract_bit_field when trying
1890          to access a non-existent part of the register.  */
1891       if (TREE_CODE (index) == INTEGER_CST
1892           && TYPE_DOMAIN (TREE_TYPE (array))
1893           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1894         {
1895           if (!c_mark_addressable (array))
1896             return error_mark_node;
1897         }
1898
1899       if (pedantic)
1900         {
1901           tree foo = array;
1902           while (TREE_CODE (foo) == COMPONENT_REF)
1903             foo = TREE_OPERAND (foo, 0);
1904           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1905             pedwarn ("ISO C forbids subscripting %<register%> array");
1906           else if (!flag_isoc99 && !lvalue_p (foo))
1907             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1908         }
1909
1910       type = TREE_TYPE (TREE_TYPE (array));
1911       if (TREE_CODE (type) != ARRAY_TYPE)
1912         type = TYPE_MAIN_VARIANT (type);
1913       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1914       /* Array ref is const/volatile if the array elements are
1915          or if the array is.  */
1916       TREE_READONLY (rval)
1917         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1918             | TREE_READONLY (array));
1919       TREE_SIDE_EFFECTS (rval)
1920         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1921             | TREE_SIDE_EFFECTS (array));
1922       TREE_THIS_VOLATILE (rval)
1923         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1924             /* This was added by rms on 16 Nov 91.
1925                It fixes  vol struct foo *a;  a->elts[1]
1926                in an inline function.
1927                Hope it doesn't break something else.  */
1928             | TREE_THIS_VOLATILE (array));
1929       return require_complete_type (fold (rval));
1930     }
1931   else
1932     {
1933       tree ar = default_conversion (array);
1934
1935       if (ar == error_mark_node)
1936         return ar;
1937
1938       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1939       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1940
1941       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1942                                  "array indexing");
1943     }
1944 }
1945 \f
1946 /* Build an external reference to identifier ID.  FUN indicates
1947    whether this will be used for a function call.  LOC is the source
1948    location of the identifier.  */
1949 tree
1950 build_external_ref (tree id, int fun, location_t loc)
1951 {
1952   tree ref;
1953   tree decl = lookup_name (id);
1954
1955   /* In Objective-C, an instance variable (ivar) may be preferred to
1956      whatever lookup_name() found.  */
1957   decl = objc_lookup_ivar (decl, id);
1958
1959   if (decl && decl != error_mark_node)
1960     ref = decl;
1961   else if (fun)
1962     /* Implicit function declaration.  */
1963     ref = implicitly_declare (id);
1964   else if (decl == error_mark_node)
1965     /* Don't complain about something that's already been
1966        complained about.  */
1967     return error_mark_node;
1968   else
1969     {
1970       undeclared_variable (id, loc);
1971       return error_mark_node;
1972     }
1973
1974   if (TREE_TYPE (ref) == error_mark_node)
1975     return error_mark_node;
1976
1977   if (TREE_DEPRECATED (ref))
1978     warn_deprecated_use (ref);
1979
1980   if (!skip_evaluation)
1981     assemble_external (ref);
1982   TREE_USED (ref) = 1;
1983
1984   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1985     {
1986       if (!in_sizeof && !in_typeof)
1987         C_DECL_USED (ref) = 1;
1988       else if (DECL_INITIAL (ref) == 0
1989                && DECL_EXTERNAL (ref)
1990                && !TREE_PUBLIC (ref))
1991         record_maybe_used_decl (ref);
1992     }
1993
1994   if (TREE_CODE (ref) == CONST_DECL)
1995     {
1996       ref = DECL_INITIAL (ref);
1997       TREE_CONSTANT (ref) = 1;
1998       TREE_INVARIANT (ref) = 1;
1999     }
2000   else if (current_function_decl != 0
2001            && !DECL_FILE_SCOPE_P (current_function_decl)
2002            && (TREE_CODE (ref) == VAR_DECL
2003                || TREE_CODE (ref) == PARM_DECL
2004                || TREE_CODE (ref) == FUNCTION_DECL))
2005     {
2006       tree context = decl_function_context (ref);
2007
2008       if (context != 0 && context != current_function_decl)
2009         DECL_NONLOCAL (ref) = 1;
2010     }
2011
2012   return ref;
2013 }
2014
2015 /* Record details of decls possibly used inside sizeof or typeof.  */
2016 struct maybe_used_decl
2017 {
2018   /* The decl.  */
2019   tree decl;
2020   /* The level seen at (in_sizeof + in_typeof).  */
2021   int level;
2022   /* The next one at this level or above, or NULL.  */
2023   struct maybe_used_decl *next;
2024 };
2025
2026 static struct maybe_used_decl *maybe_used_decls;
2027
2028 /* Record that DECL, an undefined static function reference seen
2029    inside sizeof or typeof, might be used if the operand of sizeof is
2030    a VLA type or the operand of typeof is a variably modified
2031    type.  */
2032
2033 static void
2034 record_maybe_used_decl (tree decl)
2035 {
2036   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2037   t->decl = decl;
2038   t->level = in_sizeof + in_typeof;
2039   t->next = maybe_used_decls;
2040   maybe_used_decls = t;
2041 }
2042
2043 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2044    USED is false, just discard them.  If it is true, mark them used
2045    (if no longer inside sizeof or typeof) or move them to the next
2046    level up (if still inside sizeof or typeof).  */
2047
2048 void
2049 pop_maybe_used (bool used)
2050 {
2051   struct maybe_used_decl *p = maybe_used_decls;
2052   int cur_level = in_sizeof + in_typeof;
2053   while (p && p->level > cur_level)
2054     {
2055       if (used)
2056         {
2057           if (cur_level == 0)
2058             C_DECL_USED (p->decl) = 1;
2059           else
2060             p->level = cur_level;
2061         }
2062       p = p->next;
2063     }
2064   if (!used || cur_level == 0)
2065     maybe_used_decls = p;
2066 }
2067
2068 /* Return the result of sizeof applied to EXPR.  */
2069
2070 struct c_expr
2071 c_expr_sizeof_expr (struct c_expr expr)
2072 {
2073   struct c_expr ret;
2074   if (expr.value == error_mark_node)
2075     {
2076       ret.value = error_mark_node;
2077       ret.original_code = ERROR_MARK;
2078       pop_maybe_used (false);
2079     }
2080   else
2081     {
2082       ret.value = c_sizeof (TREE_TYPE (expr.value));
2083       ret.original_code = ERROR_MARK;
2084       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2085     }
2086   return ret;
2087 }
2088
2089 /* Return the result of sizeof applied to T, a structure for the type
2090    name passed to sizeof (rather than the type itself).  */
2091
2092 struct c_expr
2093 c_expr_sizeof_type (struct c_type_name *t)
2094 {
2095   tree type;
2096   struct c_expr ret;
2097   type = groktypename (t);
2098   ret.value = c_sizeof (type);
2099   ret.original_code = ERROR_MARK;
2100   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
2101   return ret;
2102 }
2103
2104 /* Build a function call to function FUNCTION with parameters PARAMS.
2105    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2106    TREE_VALUE of each node is a parameter-expression.
2107    FUNCTION's data type may be a function type or a pointer-to-function.  */
2108
2109 tree
2110 build_function_call (tree function, tree params)
2111 {
2112   tree fntype, fundecl = 0;
2113   tree coerced_params;
2114   tree name = NULL_TREE, result;
2115   tree tem;
2116
2117   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2118   STRIP_TYPE_NOPS (function);
2119
2120   /* Convert anything with function type to a pointer-to-function.  */
2121   if (TREE_CODE (function) == FUNCTION_DECL)
2122     {
2123       /* Implement type-directed function overloading for builtins.
2124          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2125          handle all the type checking.  The result is a complete expression
2126          that implements this function call.  */
2127       tem = resolve_overloaded_builtin (function, params);
2128       if (tem)
2129         return tem;
2130
2131       name = DECL_NAME (function);
2132       fundecl = function;
2133     }
2134   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2135     function = function_to_pointer_conversion (function);
2136
2137   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2138      expressions, like those used for ObjC messenger dispatches.  */
2139   function = objc_rewrite_function_call (function, params);
2140
2141   fntype = TREE_TYPE (function);
2142
2143   if (TREE_CODE (fntype) == ERROR_MARK)
2144     return error_mark_node;
2145
2146   if (!(TREE_CODE (fntype) == POINTER_TYPE
2147         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2148     {
2149       error ("called object %qE is not a function", function);
2150       return error_mark_node;
2151     }
2152
2153   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2154     current_function_returns_abnormally = 1;
2155
2156   /* fntype now gets the type of function pointed to.  */
2157   fntype = TREE_TYPE (fntype);
2158
2159   /* Check that the function is called through a compatible prototype.
2160      If it is not, replace the call by a trap, wrapped up in a compound
2161      expression if necessary.  This has the nice side-effect to prevent
2162      the tree-inliner from generating invalid assignment trees which may
2163      blow up in the RTL expander later.  */
2164   if (TREE_CODE (function) == NOP_EXPR
2165       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2166       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2167       && !comptypes (fntype, TREE_TYPE (tem)))
2168     {
2169       tree return_type = TREE_TYPE (fntype);
2170       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2171                                        NULL_TREE);
2172
2173       /* This situation leads to run-time undefined behavior.  We can't,
2174          therefore, simply error unless we can prove that all possible
2175          executions of the program must execute the code.  */
2176       warning (0, "function called through a non-compatible type");
2177
2178       /* We can, however, treat "undefined" any way we please.
2179          Call abort to encourage the user to fix the program.  */
2180       inform ("if this code is reached, the program will abort");
2181
2182       if (VOID_TYPE_P (return_type))
2183         return trap;
2184       else
2185         {
2186           tree rhs;
2187
2188           if (AGGREGATE_TYPE_P (return_type))
2189             rhs = build_compound_literal (return_type,
2190                                           build_constructor (return_type, 0));
2191           else
2192             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2193
2194           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2195         }
2196     }
2197
2198   /* Convert the parameters to the types declared in the
2199      function prototype, or apply default promotions.  */
2200
2201   coerced_params
2202     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2203
2204   if (coerced_params == error_mark_node)
2205     return error_mark_node;
2206
2207   /* Check that the arguments to the function are valid.  */
2208
2209   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2210                             TYPE_ARG_TYPES (fntype));
2211
2212   if (require_constant_value)
2213     {
2214       result = fold_build3_initializer (CALL_EXPR, TREE_TYPE (fntype),
2215                                         function, coerced_params, NULL_TREE);
2216
2217       if (TREE_CONSTANT (result)
2218           && (name == NULL_TREE
2219               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2220         pedwarn_init ("initializer element is not constant");
2221     }
2222   else
2223     result = fold_build3 (CALL_EXPR, TREE_TYPE (fntype),
2224                           function, coerced_params, NULL_TREE);
2225
2226   if (VOID_TYPE_P (TREE_TYPE (result)))
2227     return result;
2228   return require_complete_type (result);
2229 }
2230 \f
2231 /* Convert the argument expressions in the list VALUES
2232    to the types in the list TYPELIST.  The result is a list of converted
2233    argument expressions, unless there are too few arguments in which
2234    case it is error_mark_node.
2235
2236    If TYPELIST is exhausted, or when an element has NULL as its type,
2237    perform the default conversions.
2238
2239    PARMLIST is the chain of parm decls for the function being called.
2240    It may be 0, if that info is not available.
2241    It is used only for generating error messages.
2242
2243    FUNCTION is a tree for the called function.  It is used only for
2244    error messages, where it is formatted with %qE.
2245
2246    This is also where warnings about wrong number of args are generated.
2247
2248    Both VALUES and the returned value are chains of TREE_LIST nodes
2249    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2250
2251 static tree
2252 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2253 {
2254   tree typetail, valtail;
2255   tree result = NULL;
2256   int parmnum;
2257   tree selector;
2258
2259   /* Change pointer to function to the function itself for
2260      diagnostics.  */
2261   if (TREE_CODE (function) == ADDR_EXPR
2262       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2263     function = TREE_OPERAND (function, 0);
2264
2265   /* Handle an ObjC selector specially for diagnostics.  */
2266   selector = objc_message_selector ();
2267
2268   /* Scan the given expressions and types, producing individual
2269      converted arguments and pushing them on RESULT in reverse order.  */
2270
2271   for (valtail = values, typetail = typelist, parmnum = 0;
2272        valtail;
2273        valtail = TREE_CHAIN (valtail), parmnum++)
2274     {
2275       tree type = typetail ? TREE_VALUE (typetail) : 0;
2276       tree val = TREE_VALUE (valtail);
2277       tree rname = function;
2278       int argnum = parmnum + 1;
2279       const char *invalid_func_diag;
2280
2281       if (type == void_type_node)
2282         {
2283           error ("too many arguments to function %qE", function);
2284           break;
2285         }
2286
2287       if (selector && argnum > 2)
2288         {
2289           rname = selector;
2290           argnum -= 2;
2291         }
2292
2293       STRIP_TYPE_NOPS (val);
2294
2295       val = require_complete_type (val);
2296
2297       if (type != 0)
2298         {
2299           /* Formal parm type is specified by a function prototype.  */
2300           tree parmval;
2301
2302           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2303             {
2304               error ("type of formal parameter %d is incomplete", parmnum + 1);
2305               parmval = val;
2306             }
2307           else
2308             {
2309               /* Optionally warn about conversions that
2310                  differ from the default conversions.  */
2311               if (warn_conversion || warn_traditional)
2312                 {
2313                   unsigned int formal_prec = TYPE_PRECISION (type);
2314
2315                   if (INTEGRAL_TYPE_P (type)
2316                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2317                     warning (0, "passing argument %d of %qE as integer "
2318                              "rather than floating due to prototype",
2319                              argnum, rname);
2320                   if (INTEGRAL_TYPE_P (type)
2321                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2322                     warning (0, "passing argument %d of %qE as integer "
2323                              "rather than complex due to prototype",
2324                              argnum, rname);
2325                   else if (TREE_CODE (type) == COMPLEX_TYPE
2326                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2327                     warning (0, "passing argument %d of %qE as complex "
2328                              "rather than floating due to prototype",
2329                              argnum, rname);
2330                   else if (TREE_CODE (type) == REAL_TYPE
2331                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2332                     warning (0, "passing argument %d of %qE as floating "
2333                              "rather than integer due to prototype",
2334                              argnum, rname);
2335                   else if (TREE_CODE (type) == COMPLEX_TYPE
2336                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2337                     warning (0, "passing argument %d of %qE as complex "
2338                              "rather than integer due to prototype",
2339                              argnum, rname);
2340                   else if (TREE_CODE (type) == REAL_TYPE
2341                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2342                     warning (0, "passing argument %d of %qE as floating "
2343                              "rather than complex due to prototype",
2344                              argnum, rname);
2345                   /* ??? At some point, messages should be written about
2346                      conversions between complex types, but that's too messy
2347                      to do now.  */
2348                   else if (TREE_CODE (type) == REAL_TYPE
2349                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2350                     {
2351                       /* Warn if any argument is passed as `float',
2352                          since without a prototype it would be `double'.  */
2353                       if (formal_prec == TYPE_PRECISION (float_type_node))
2354                         warning (0, "passing argument %d of %qE as %<float%> "
2355                                  "rather than %<double%> due to prototype",
2356                                  argnum, rname);
2357                     }
2358                   /* Detect integer changing in width or signedness.
2359                      These warnings are only activated with
2360                      -Wconversion, not with -Wtraditional.  */
2361                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2362                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2363                     {
2364                       tree would_have_been = default_conversion (val);
2365                       tree type1 = TREE_TYPE (would_have_been);
2366
2367                       if (TREE_CODE (type) == ENUMERAL_TYPE
2368                           && (TYPE_MAIN_VARIANT (type)
2369                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2370                         /* No warning if function asks for enum
2371                            and the actual arg is that enum type.  */
2372                         ;
2373                       else if (formal_prec != TYPE_PRECISION (type1))
2374                         warning (OPT_Wconversion, "passing argument %d of %qE "
2375                                  "with different width due to prototype",
2376                                  argnum, rname);
2377                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2378                         ;
2379                       /* Don't complain if the formal parameter type
2380                          is an enum, because we can't tell now whether
2381                          the value was an enum--even the same enum.  */
2382                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2383                         ;
2384                       else if (TREE_CODE (val) == INTEGER_CST
2385                                && int_fits_type_p (val, type))
2386                         /* Change in signedness doesn't matter
2387                            if a constant value is unaffected.  */
2388                         ;
2389                       /* If the value is extended from a narrower
2390                          unsigned type, it doesn't matter whether we
2391                          pass it as signed or unsigned; the value
2392                          certainly is the same either way.  */
2393                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2394                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2395                         ;
2396                       else if (TYPE_UNSIGNED (type))
2397                         warning (OPT_Wconversion, "passing argument %d of %qE "
2398                                  "as unsigned due to prototype",
2399                                  argnum, rname);
2400                       else
2401                         warning (OPT_Wconversion, "passing argument %d of %qE "
2402                                  "as signed due to prototype", argnum, rname);
2403                     }
2404                 }
2405
2406               parmval = convert_for_assignment (type, val, ic_argpass,
2407                                                 fundecl, function,
2408                                                 parmnum + 1);
2409
2410               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2411                   && INTEGRAL_TYPE_P (type)
2412                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2413                 parmval = default_conversion (parmval);
2414             }
2415           result = tree_cons (NULL_TREE, parmval, result);
2416         }
2417       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2418                && (TYPE_PRECISION (TREE_TYPE (val))
2419                    < TYPE_PRECISION (double_type_node)))
2420         /* Convert `float' to `double'.  */
2421         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2422       else if ((invalid_func_diag =
2423                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2424         {
2425           error (invalid_func_diag);
2426           return error_mark_node;
2427         }
2428       else
2429         /* Convert `short' and `char' to full-size `int'.  */
2430         result = tree_cons (NULL_TREE, default_conversion (val), result);
2431
2432       if (typetail)
2433         typetail = TREE_CHAIN (typetail);
2434     }
2435
2436   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2437     {
2438       error ("too few arguments to function %qE", function);
2439       return error_mark_node;
2440     }
2441
2442   return nreverse (result);
2443 }
2444 \f
2445 /* This is the entry point used by the parser to build unary operators
2446    in the input.  CODE, a tree_code, specifies the unary operator, and
2447    ARG is the operand.  For unary plus, the C parser currently uses
2448    CONVERT_EXPR for code.  */
2449
2450 struct c_expr
2451 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2452 {
2453   struct c_expr result;
2454
2455   result.original_code = ERROR_MARK;
2456   result.value = build_unary_op (code, arg.value, 0);
2457   overflow_warning (result.value);
2458   return result;
2459 }
2460
2461 /* This is the entry point used by the parser to build binary operators
2462    in the input.  CODE, a tree_code, specifies the binary operator, and
2463    ARG1 and ARG2 are the operands.  In addition to constructing the
2464    expression, we check for operands that were written with other binary
2465    operators in a way that is likely to confuse the user.  */
2466
2467 struct c_expr
2468 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2469                         struct c_expr arg2)
2470 {
2471   struct c_expr result;
2472
2473   enum tree_code code1 = arg1.original_code;
2474   enum tree_code code2 = arg2.original_code;
2475
2476   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2477   result.original_code = code;
2478
2479   if (TREE_CODE (result.value) == ERROR_MARK)
2480     return result;
2481
2482   /* Check for cases such as x+y<<z which users are likely
2483      to misinterpret.  */
2484   if (warn_parentheses)
2485     {
2486       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2487         {
2488           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2489               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2490             warning (OPT_Wparentheses,
2491                      "suggest parentheses around + or - inside shift");
2492         }
2493
2494       if (code == TRUTH_ORIF_EXPR)
2495         {
2496           if (code1 == TRUTH_ANDIF_EXPR
2497               || code2 == TRUTH_ANDIF_EXPR)
2498             warning (OPT_Wparentheses,
2499                      "suggest parentheses around && within ||");
2500         }
2501
2502       if (code == BIT_IOR_EXPR)
2503         {
2504           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2505               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2506               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2507               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2508             warning (OPT_Wparentheses,
2509                      "suggest parentheses around arithmetic in operand of |");
2510           /* Check cases like x|y==z */
2511           if (TREE_CODE_CLASS (code1) == tcc_comparison
2512               || TREE_CODE_CLASS (code2) == tcc_comparison)
2513             warning (OPT_Wparentheses,
2514                      "suggest parentheses around comparison in operand of |");
2515         }
2516
2517       if (code == BIT_XOR_EXPR)
2518         {
2519           if (code1 == BIT_AND_EXPR
2520               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2521               || code2 == BIT_AND_EXPR
2522               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2523             warning (OPT_Wparentheses,
2524                      "suggest parentheses around arithmetic in operand of ^");
2525           /* Check cases like x^y==z */
2526           if (TREE_CODE_CLASS (code1) == tcc_comparison
2527               || TREE_CODE_CLASS (code2) == tcc_comparison)
2528             warning (OPT_Wparentheses,
2529                      "suggest parentheses around comparison in operand of ^");
2530         }
2531
2532       if (code == BIT_AND_EXPR)
2533         {
2534           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2535               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2536             warning (OPT_Wparentheses,
2537                      "suggest parentheses around + or - in operand of &");
2538           /* Check cases like x&y==z */
2539           if (TREE_CODE_CLASS (code1) == tcc_comparison
2540               || TREE_CODE_CLASS (code2) == tcc_comparison)
2541             warning (OPT_Wparentheses,
2542                      "suggest parentheses around comparison in operand of &");
2543         }
2544       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2545       if (TREE_CODE_CLASS (code) == tcc_comparison
2546           && (TREE_CODE_CLASS (code1) == tcc_comparison
2547               || TREE_CODE_CLASS (code2) == tcc_comparison))
2548         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2549                  "have their mathematical meaning");
2550
2551     }
2552
2553   unsigned_conversion_warning (result.value, arg1.value);
2554   unsigned_conversion_warning (result.value, arg2.value);
2555   overflow_warning (result.value);
2556
2557   return result;
2558 }
2559 \f
2560 /* Return a tree for the difference of pointers OP0 and OP1.
2561    The resulting tree has type int.  */
2562
2563 static tree
2564 pointer_diff (tree op0, tree op1)
2565 {
2566   tree restype = ptrdiff_type_node;
2567
2568   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2569   tree con0, con1, lit0, lit1;
2570   tree orig_op1 = op1;
2571
2572   if (pedantic || warn_pointer_arith)
2573     {
2574       if (TREE_CODE (target_type) == VOID_TYPE)
2575         pedwarn ("pointer of type %<void *%> used in subtraction");
2576       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2577         pedwarn ("pointer to a function used in subtraction");
2578     }
2579
2580   /* If the conversion to ptrdiff_type does anything like widening or
2581      converting a partial to an integral mode, we get a convert_expression
2582      that is in the way to do any simplifications.
2583      (fold-const.c doesn't know that the extra bits won't be needed.
2584      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2585      different mode in place.)
2586      So first try to find a common term here 'by hand'; we want to cover
2587      at least the cases that occur in legal static initializers.  */
2588   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2589   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2590
2591   if (TREE_CODE (con0) == PLUS_EXPR)
2592     {
2593       lit0 = TREE_OPERAND (con0, 1);
2594       con0 = TREE_OPERAND (con0, 0);
2595     }
2596   else
2597     lit0 = integer_zero_node;
2598
2599   if (TREE_CODE (con1) == PLUS_EXPR)
2600     {
2601       lit1 = TREE_OPERAND (con1, 1);
2602       con1 = TREE_OPERAND (con1, 0);
2603     }
2604   else
2605     lit1 = integer_zero_node;
2606
2607   if (operand_equal_p (con0, con1, 0))
2608     {
2609       op0 = lit0;
2610       op1 = lit1;
2611     }
2612
2613
2614   /* First do the subtraction as integers;
2615      then drop through to build the divide operator.
2616      Do not do default conversions on the minus operator
2617      in case restype is a short type.  */
2618
2619   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2620                          convert (restype, op1), 0);
2621   /* This generates an error if op1 is pointer to incomplete type.  */
2622   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2623     error ("arithmetic on pointer to an incomplete type");
2624
2625   /* This generates an error if op0 is pointer to incomplete type.  */
2626   op1 = c_size_in_bytes (target_type);
2627
2628   /* Divide by the size, in easiest possible way.  */
2629   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2630 }
2631 \f
2632 /* Construct and perhaps optimize a tree representation
2633    for a unary operation.  CODE, a tree_code, specifies the operation
2634    and XARG is the operand.
2635    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2636    the default promotions (such as from short to int).
2637    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2638    allows non-lvalues; this is only used to handle conversion of non-lvalue
2639    arrays to pointers in C99.  */
2640
2641 tree
2642 build_unary_op (enum tree_code code, tree xarg, int flag)
2643 {
2644   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2645   tree arg = xarg;
2646   tree argtype = 0;
2647   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2648   tree val;
2649   int noconvert = flag;
2650   const char *invalid_op_diag;
2651
2652   if (typecode == ERROR_MARK)
2653     return error_mark_node;
2654   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2655     typecode = INTEGER_TYPE;
2656
2657   if ((invalid_op_diag
2658        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2659     {
2660       error (invalid_op_diag);
2661       return error_mark_node;
2662     }
2663
2664   switch (code)
2665     {
2666     case CONVERT_EXPR:
2667       /* This is used for unary plus, because a CONVERT_EXPR
2668          is enough to prevent anybody from looking inside for
2669          associativity, but won't generate any code.  */
2670       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2671             || typecode == COMPLEX_TYPE
2672             || typecode == VECTOR_TYPE))
2673         {
2674           error ("wrong type argument to unary plus");
2675           return error_mark_node;
2676         }
2677       else if (!noconvert)
2678         arg = default_conversion (arg);
2679       arg = non_lvalue (arg);
2680       break;
2681
2682     case NEGATE_EXPR:
2683       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2684             || typecode == COMPLEX_TYPE
2685             || typecode == VECTOR_TYPE))
2686         {
2687           error ("wrong type argument to unary minus");
2688           return error_mark_node;
2689         }
2690       else if (!noconvert)
2691         arg = default_conversion (arg);
2692       break;
2693
2694     case BIT_NOT_EXPR:
2695       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2696         {
2697           if (!noconvert)
2698             arg = default_conversion (arg);
2699         }
2700       else if (typecode == COMPLEX_TYPE)
2701         {
2702           code = CONJ_EXPR;
2703           if (pedantic)
2704             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2705           if (!noconvert)
2706             arg = default_conversion (arg);
2707         }
2708       else
2709         {
2710           error ("wrong type argument to bit-complement");
2711           return error_mark_node;
2712         }
2713       break;
2714
2715     case ABS_EXPR:
2716       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2717         {
2718           error ("wrong type argument to abs");
2719           return error_mark_node;
2720         }
2721       else if (!noconvert)
2722         arg = default_conversion (arg);
2723       break;
2724
2725     case CONJ_EXPR:
2726       /* Conjugating a real value is a no-op, but allow it anyway.  */
2727       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2728             || typecode == COMPLEX_TYPE))
2729         {
2730           error ("wrong type argument to conjugation");
2731           return error_mark_node;
2732         }
2733       else if (!noconvert)
2734         arg = default_conversion (arg);
2735       break;
2736
2737     case TRUTH_NOT_EXPR:
2738       if (typecode != INTEGER_TYPE
2739           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2740           && typecode != COMPLEX_TYPE)
2741         {
2742           error ("wrong type argument to unary exclamation mark");
2743           return error_mark_node;
2744         }
2745       arg = c_objc_common_truthvalue_conversion (arg);
2746       return invert_truthvalue (arg);
2747
2748     case NOP_EXPR:
2749       break;
2750
2751     case REALPART_EXPR:
2752       if (TREE_CODE (arg) == COMPLEX_CST)
2753         return TREE_REALPART (arg);
2754       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2755         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2756       else
2757         return arg;
2758
2759     case IMAGPART_EXPR:
2760       if (TREE_CODE (arg) == COMPLEX_CST)
2761         return TREE_IMAGPART (arg);
2762       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2763         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2764       else
2765         return convert (TREE_TYPE (arg), integer_zero_node);
2766
2767     case PREINCREMENT_EXPR:
2768     case POSTINCREMENT_EXPR:
2769     case PREDECREMENT_EXPR:
2770     case POSTDECREMENT_EXPR:
2771
2772       /* Increment or decrement the real part of the value,
2773          and don't change the imaginary part.  */
2774       if (typecode == COMPLEX_TYPE)
2775         {
2776           tree real, imag;
2777
2778           if (pedantic)
2779             pedwarn ("ISO C does not support %<++%> and %<--%>"
2780                      " on complex types");
2781
2782           arg = stabilize_reference (arg);
2783           real = build_unary_op (REALPART_EXPR, arg, 1);
2784           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2785           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2786                          build_unary_op (code, real, 1), imag);
2787         }
2788
2789       /* Report invalid types.  */
2790
2791       if (typecode != POINTER_TYPE
2792           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2793         {
2794           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2795             error ("wrong type argument to increment");
2796           else
2797             error ("wrong type argument to decrement");
2798
2799           return error_mark_node;
2800         }
2801
2802       {
2803         tree inc;
2804         tree result_type = TREE_TYPE (arg);
2805
2806         arg = get_unwidened (arg, 0);
2807         argtype = TREE_TYPE (arg);
2808
2809         /* Compute the increment.  */
2810
2811         if (typecode == POINTER_TYPE)
2812           {
2813             /* If pointer target is an undefined struct,
2814                we just cannot know how to do the arithmetic.  */
2815             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2816               {
2817                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2818                   error ("increment of pointer to unknown structure");
2819                 else
2820                   error ("decrement of pointer to unknown structure");
2821               }
2822             else if ((pedantic || warn_pointer_arith)
2823                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2824                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2825               {
2826                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2827                   pedwarn ("wrong type argument to increment");
2828                 else
2829                   pedwarn ("wrong type argument to decrement");
2830               }
2831
2832             inc = c_size_in_bytes (TREE_TYPE (result_type));
2833           }
2834         else
2835           inc = integer_one_node;
2836
2837         inc = convert (argtype, inc);
2838
2839         /* Complain about anything else that is not a true lvalue.  */
2840         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2841                                     || code == POSTINCREMENT_EXPR)
2842                                    ? lv_increment
2843                                    : lv_decrement)))
2844           return error_mark_node;
2845
2846         /* Report a read-only lvalue.  */
2847         if (TREE_READONLY (arg))
2848           readonly_error (arg,
2849                           ((code == PREINCREMENT_EXPR
2850                             || code == POSTINCREMENT_EXPR)
2851                            ? lv_increment : lv_decrement));
2852
2853         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2854           val = boolean_increment (code, arg);
2855         else
2856           val = build2 (code, TREE_TYPE (arg), arg, inc);
2857         TREE_SIDE_EFFECTS (val) = 1;
2858         val = convert (result_type, val);
2859         if (TREE_CODE (val) != code)
2860           TREE_NO_WARNING (val) = 1;
2861         return val;
2862       }
2863
2864     case ADDR_EXPR:
2865       /* Note that this operation never does default_conversion.  */
2866
2867       /* Let &* cancel out to simplify resulting code.  */
2868       if (TREE_CODE (arg) == INDIRECT_REF)
2869         {
2870           /* Don't let this be an lvalue.  */
2871           if (lvalue_p (TREE_OPERAND (arg, 0)))
2872             return non_lvalue (TREE_OPERAND (arg, 0));
2873           return TREE_OPERAND (arg, 0);
2874         }
2875
2876       /* For &x[y], return x+y */
2877       if (TREE_CODE (arg) == ARRAY_REF)
2878         {
2879           tree op0 = TREE_OPERAND (arg, 0);
2880           if (!c_mark_addressable (op0))
2881             return error_mark_node;
2882           return build_binary_op (PLUS_EXPR,
2883                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2884                                    ? array_to_pointer_conversion (op0)
2885                                    : op0),
2886                                   TREE_OPERAND (arg, 1), 1);
2887         }
2888
2889       /* Anything not already handled and not a true memory reference
2890          or a non-lvalue array is an error.  */
2891       else if (typecode != FUNCTION_TYPE && !flag
2892                && !lvalue_or_else (arg, lv_addressof))
2893         return error_mark_node;
2894
2895       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2896       argtype = TREE_TYPE (arg);
2897
2898       /* If the lvalue is const or volatile, merge that into the type
2899          to which the address will point.  Note that you can't get a
2900          restricted pointer by taking the address of something, so we
2901          only have to deal with `const' and `volatile' here.  */
2902       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2903           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2904           argtype = c_build_type_variant (argtype,
2905                                           TREE_READONLY (arg),
2906                                           TREE_THIS_VOLATILE (arg));
2907
2908       if (!c_mark_addressable (arg))
2909         return error_mark_node;
2910
2911       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2912                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2913
2914       argtype = build_pointer_type (argtype);
2915
2916       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2917          when we have proper support for integer constant expressions.  */
2918       val = get_base_address (arg);
2919       if (val && TREE_CODE (val) == INDIRECT_REF
2920           && integer_zerop (TREE_OPERAND (val, 0)))
2921         return fold_convert (argtype, fold_offsetof (arg));
2922
2923       val = build1 (ADDR_EXPR, argtype, arg);
2924
2925       return val;
2926
2927     default:
2928       break;
2929     }
2930
2931   if (argtype == 0)
2932     argtype = TREE_TYPE (arg);
2933   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
2934                                 : fold_build1 (code, argtype, arg);
2935 }
2936
2937 /* Return nonzero if REF is an lvalue valid for this language.
2938    Lvalues can be assigned, unless their type has TYPE_READONLY.
2939    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2940
2941 static int
2942 lvalue_p (tree ref)
2943 {
2944   enum tree_code code = TREE_CODE (ref);
2945
2946   switch (code)
2947     {
2948     case REALPART_EXPR:
2949     case IMAGPART_EXPR:
2950     case COMPONENT_REF:
2951       return lvalue_p (TREE_OPERAND (ref, 0));
2952
2953     case COMPOUND_LITERAL_EXPR:
2954     case STRING_CST:
2955       return 1;
2956
2957     case INDIRECT_REF:
2958     case ARRAY_REF:
2959     case VAR_DECL:
2960     case PARM_DECL:
2961     case RESULT_DECL:
2962     case ERROR_MARK:
2963       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2964               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2965
2966     case BIND_EXPR:
2967       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2968
2969     default:
2970       return 0;
2971     }
2972 }
2973 \f
2974 /* Give an error for storing in something that is 'const'.  */
2975
2976 static void
2977 readonly_error (tree arg, enum lvalue_use use)
2978 {
2979   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
2980               || use == lv_asm);
2981   /* Using this macro rather than (for example) arrays of messages
2982      ensures that all the format strings are checked at compile
2983      time.  */
2984 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
2985                                    : (use == lv_increment ? (I)         \
2986                                    : (use == lv_decrement ? (D) : (AS))))
2987   if (TREE_CODE (arg) == COMPONENT_REF)
2988     {
2989       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2990         readonly_error (TREE_OPERAND (arg, 0), use);
2991       else
2992         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2993                              G_("increment of read-only member %qD"),
2994                              G_("decrement of read-only member %qD"),
2995                              G_("read-only member %qD used as %<asm%> output")),
2996                TREE_OPERAND (arg, 1));
2997     }
2998   else if (TREE_CODE (arg) == VAR_DECL)
2999     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3000                          G_("increment of read-only variable %qD"),
3001                          G_("decrement of read-only variable %qD"),
3002                          G_("read-only variable %qD used as %<asm%> output")),
3003            arg);
3004   else
3005     error (READONLY_MSG (G_("assignment of read-only location"),
3006                          G_("increment of read-only location"),
3007                          G_("decrement of read-only location"),
3008                          G_("read-only location used as %<asm%> output")));
3009 }
3010
3011
3012 /* Return nonzero if REF is an lvalue valid for this language;
3013    otherwise, print an error message and return zero.  USE says
3014    how the lvalue is being used and so selects the error message.  */
3015
3016 static int
3017 lvalue_or_else (tree ref, enum lvalue_use use)
3018 {
3019   int win = lvalue_p (ref);
3020
3021   if (!win)
3022     lvalue_error (use);
3023
3024   return win;
3025 }
3026 \f
3027 /* Mark EXP saying that we need to be able to take the
3028    address of it; it should not be allocated in a register.
3029    Returns true if successful.  */
3030
3031 bool
3032 c_mark_addressable (tree exp)
3033 {
3034   tree x = exp;
3035
3036   while (1)
3037     switch (TREE_CODE (x))
3038       {
3039       case COMPONENT_REF:
3040         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3041           {
3042             error
3043               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3044             return false;
3045           }
3046
3047         /* ... fall through ...  */
3048
3049       case ADDR_EXPR:
3050       case ARRAY_REF:
3051       case REALPART_EXPR:
3052       case IMAGPART_EXPR:
3053         x = TREE_OPERAND (x, 0);
3054         break;
3055
3056       case COMPOUND_LITERAL_EXPR:
3057       case CONSTRUCTOR:
3058         TREE_ADDRESSABLE (x) = 1;
3059         return true;
3060
3061       case VAR_DECL:
3062       case CONST_DECL:
3063       case PARM_DECL:
3064       case RESULT_DECL:
3065         if (C_DECL_REGISTER (x)
3066             && DECL_NONLOCAL (x))
3067           {
3068             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3069               {
3070                 error
3071                   ("global register variable %qD used in nested function", x);
3072                 return false;
3073               }
3074             pedwarn ("register variable %qD used in nested function", x);
3075           }
3076         else if (C_DECL_REGISTER (x))
3077           {
3078             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3079               error ("address of global register variable %qD requested", x);
3080             else
3081               error ("address of register variable %qD requested", x);
3082             return false;
3083           }
3084
3085         /* drops in */
3086       case FUNCTION_DECL:
3087         TREE_ADDRESSABLE (x) = 1;
3088         /* drops out */
3089       default:
3090         return true;
3091     }
3092 }
3093 \f
3094 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3095
3096 tree
3097 build_conditional_expr (tree ifexp, tree op1, tree op2)
3098 {
3099   tree type1;
3100   tree type2;
3101   enum tree_code code1;
3102   enum tree_code code2;
3103   tree result_type = NULL;
3104   tree orig_op1 = op1, orig_op2 = op2;
3105
3106   /* Promote both alternatives.  */
3107
3108   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3109     op1 = default_conversion (op1);
3110   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3111     op2 = default_conversion (op2);
3112
3113   if (TREE_CODE (ifexp) == ERROR_MARK
3114       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3115       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3116     return error_mark_node;
3117
3118   type1 = TREE_TYPE (op1);
3119   code1 = TREE_CODE (type1);
3120   type2 = TREE_TYPE (op2);
3121   code2 = TREE_CODE (type2);
3122
3123   /* C90 does not permit non-lvalue arrays in conditional expressions.
3124      In C99 they will be pointers by now.  */
3125   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3126     {
3127       error ("non-lvalue array in conditional expression");
3128       return error_mark_node;
3129     }
3130
3131   /* Quickly detect the usual case where op1 and op2 have the same type
3132      after promotion.  */
3133   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3134     {
3135       if (type1 == type2)
3136         result_type = type1;
3137       else
3138         result_type = TYPE_MAIN_VARIANT (type1);
3139     }
3140   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3141             || code1 == COMPLEX_TYPE)
3142            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3143                || code2 == COMPLEX_TYPE))
3144     {
3145       result_type = c_common_type (type1, type2);
3146
3147       /* If -Wsign-compare, warn here if type1 and type2 have
3148          different signedness.  We'll promote the signed to unsigned
3149          and later code won't know it used to be different.
3150          Do this check on the original types, so that explicit casts
3151          will be considered, but default promotions won't.  */
3152       if (warn_sign_compare && !skip_evaluation)
3153         {
3154           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3155           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3156
3157           if (unsigned_op1 ^ unsigned_op2)
3158             {
3159               /* Do not warn if the result type is signed, since the
3160                  signed type will only be chosen if it can represent
3161                  all the values of the unsigned type.  */
3162               if (!TYPE_UNSIGNED (result_type))
3163                 /* OK */;
3164               /* Do not warn if the signed quantity is an unsuffixed
3165                  integer literal (or some static constant expression
3166                  involving such literals) and it is non-negative.  */
3167               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3168                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3169                 /* OK */;
3170               else
3171                 warning (0, "signed and unsigned type in conditional expression");
3172             }
3173         }
3174     }
3175   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3176     {
3177       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3178         pedwarn ("ISO C forbids conditional expr with only one void side");
3179       result_type = void_type_node;
3180     }
3181   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3182     {
3183       if (comp_target_types (type1, type2))
3184         result_type = common_pointer_type (type1, type2);
3185       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3186                && TREE_CODE (orig_op1) != NOP_EXPR)
3187         result_type = qualify_type (type2, type1);
3188       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3189                && TREE_CODE (orig_op2) != NOP_EXPR)
3190         result_type = qualify_type (type1, type2);
3191       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3192         {
3193           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3194             pedwarn ("ISO C forbids conditional expr between "
3195                      "%<void *%> and function pointer");
3196           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3197                                                           TREE_TYPE (type2)));
3198         }
3199       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3200         {
3201           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3202             pedwarn ("ISO C forbids conditional expr between "
3203                      "%<void *%> and function pointer");
3204           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3205                                                           TREE_TYPE (type1)));
3206         }
3207       else
3208         {
3209           pedwarn ("pointer type mismatch in conditional expression");
3210           result_type = build_pointer_type (void_type_node);
3211         }
3212     }
3213   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3214     {
3215       if (!integer_zerop (op2))
3216         pedwarn ("pointer/integer type mismatch in conditional expression");
3217       else
3218         {
3219           op2 = null_pointer_node;
3220         }
3221       result_type = type1;
3222     }
3223   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3224     {
3225       if (!integer_zerop (op1))
3226         pedwarn ("pointer/integer type mismatch in conditional expression");
3227       else
3228         {
3229           op1 = null_pointer_node;
3230         }
3231       result_type = type2;
3232     }
3233
3234   if (!result_type)
3235     {
3236       if (flag_cond_mismatch)
3237         result_type = void_type_node;
3238       else
3239         {
3240           error ("type mismatch in conditional expression");
3241           return error_mark_node;
3242         }
3243     }
3244
3245   /* Merge const and volatile flags of the incoming types.  */
3246   result_type
3247     = build_type_variant (result_type,
3248                           TREE_READONLY (op1) || TREE_READONLY (op2),
3249                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3250
3251   if (result_type != TREE_TYPE (op1))
3252     op1 = convert_and_check (result_type, op1);
3253   if (result_type != TREE_TYPE (op2))
3254     op2 = convert_and_check (result_type, op2);
3255
3256   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3257 }
3258 \f
3259 /* Return a compound expression that performs two expressions and
3260    returns the value of the second of them.  */
3261
3262 tree
3263 build_compound_expr (tree expr1, tree expr2)
3264 {
3265   if (!TREE_SIDE_EFFECTS (expr1))
3266     {
3267       /* The left-hand operand of a comma expression is like an expression
3268          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3269          any side-effects, unless it was explicitly cast to (void).  */
3270       if (warn_unused_value)
3271         {
3272           if (VOID_TYPE_P (TREE_TYPE (expr1))
3273               && TREE_CODE (expr1) == CONVERT_EXPR)
3274             ; /* (void) a, b */
3275           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3276                    && TREE_CODE (expr1) == COMPOUND_EXPR
3277                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3278             ; /* (void) a, (void) b, c */
3279           else
3280             warning (0, "left-hand operand of comma expression has no effect");
3281         }
3282     }
3283
3284   /* With -Wunused, we should also warn if the left-hand operand does have
3285      side-effects, but computes a value which is not used.  For example, in
3286      `foo() + bar(), baz()' the result of the `+' operator is not used,
3287      so we should issue a warning.  */
3288   else if (warn_unused_value)
3289     warn_if_unused_value (expr1, input_location);
3290
3291   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3292 }
3293
3294 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3295
3296 tree
3297 build_c_cast (tree type, tree expr)
3298 {
3299   tree value = expr;
3300
3301   if (type == error_mark_node || expr == error_mark_node)
3302     return error_mark_node;
3303
3304   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3305      only in <protocol> qualifications.  But when constructing cast expressions,
3306      the protocols do matter and must be kept around.  */
3307   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3308     return build1 (NOP_EXPR, type, expr);
3309
3310   type = TYPE_MAIN_VARIANT (type);
3311
3312   if (TREE_CODE (type) == ARRAY_TYPE)
3313     {
3314       error ("cast specifies array type");
3315       return error_mark_node;
3316     }
3317
3318   if (TREE_CODE (type) == FUNCTION_TYPE)
3319     {
3320       error ("cast specifies function type");
3321       return error_mark_node;
3322     }
3323
3324   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3325     {
3326       if (pedantic)
3327         {
3328           if (TREE_CODE (type) == RECORD_TYPE
3329               || TREE_CODE (type) == UNION_TYPE)
3330             pedwarn ("ISO C forbids casting nonscalar to the same type");
3331         }
3332     }
3333   else if (TREE_CODE (type) == UNION_TYPE)
3334     {
3335       tree field;
3336
3337       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3338         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3339                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3340           break;
3341
3342       if (field)
3343         {
3344           tree t;
3345
3346           if (pedantic)
3347             pedwarn ("ISO C forbids casts to union type");
3348           t = digest_init (type,
3349                            build_constructor_single (type, field, value),
3350                            true, 0);
3351           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3352           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3353           return t;
3354         }
3355       error ("cast to union type from type not present in union");
3356       return error_mark_node;
3357     }
3358   else
3359     {
3360       tree otype, ovalue;
3361
3362       if (type == void_type_node)
3363         return build1 (CONVERT_EXPR, type, value);
3364
3365       otype = TREE_TYPE (value);
3366
3367       /* Optionally warn about potentially worrisome casts.  */
3368
3369       if (warn_cast_qual
3370           && TREE_CODE (type) == POINTER_TYPE
3371           && TREE_CODE (otype) == POINTER_TYPE)
3372         {
3373           tree in_type = type;
3374           tree in_otype = otype;
3375           int added = 0;
3376           int discarded = 0;
3377
3378           /* Check that the qualifiers on IN_TYPE are a superset of
3379              the qualifiers of IN_OTYPE.  The outermost level of
3380              POINTER_TYPE nodes is uninteresting and we stop as soon
3381              as we hit a non-POINTER_TYPE node on either type.  */
3382           do
3383             {
3384               in_otype = TREE_TYPE (in_otype);
3385               in_type = TREE_TYPE (in_type);
3386
3387               /* GNU C allows cv-qualified function types.  'const'
3388                  means the function is very pure, 'volatile' means it
3389                  can't return.  We need to warn when such qualifiers
3390                  are added, not when they're taken away.  */
3391               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3392                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3393                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3394               else
3395                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3396             }
3397           while (TREE_CODE (in_type) == POINTER_TYPE
3398                  && TREE_CODE (in_otype) == POINTER_TYPE);
3399
3400           if (added)
3401             warning (0, "cast adds new qualifiers to function type");
3402
3403           if (discarded)
3404             /* There are qualifiers present in IN_OTYPE that are not
3405                present in IN_TYPE.  */
3406             warning (0, "cast discards qualifiers from pointer target type");
3407         }
3408
3409       /* Warn about possible alignment problems.  */
3410       if (STRICT_ALIGNMENT
3411           && TREE_CODE (type) == POINTER_TYPE
3412           && TREE_CODE (otype) == POINTER_TYPE
3413           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3414           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3415           /* Don't warn about opaque types, where the actual alignment
3416              restriction is unknown.  */
3417           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3418                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3419                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3420           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3421         warning (OPT_Wcast_align,
3422                  "cast increases required alignment of target type");
3423
3424       if (TREE_CODE (type) == INTEGER_TYPE
3425           && TREE_CODE (otype) == POINTER_TYPE
3426           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3427           && !TREE_CONSTANT (value))
3428         warning (OPT_Wpointer_to_int_cast,
3429                  "cast from pointer to integer of different size");
3430
3431       if (TREE_CODE (value) == CALL_EXPR
3432           && TREE_CODE (type) != TREE_CODE (otype))
3433         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3434                  "to non-matching type %qT", otype, type);
3435
3436       if (TREE_CODE (type) == POINTER_TYPE
3437           && TREE_CODE (otype) == INTEGER_TYPE
3438           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3439           /* Don't warn about converting any constant.  */
3440           && !TREE_CONSTANT (value))
3441         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3442                  "of different size");
3443
3444       strict_aliasing_warning (otype, type, expr);
3445
3446       /* If pedantic, warn for conversions between function and object
3447          pointer types, except for converting a null pointer constant
3448          to function pointer type.  */
3449       if (pedantic
3450           && TREE_CODE (type) == POINTER_TYPE
3451           && TREE_CODE (otype) == POINTER_TYPE
3452           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3453           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3454         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3455
3456       if (pedantic
3457           && TREE_CODE (type) == POINTER_TYPE
3458           && TREE_CODE (otype) == POINTER_TYPE
3459           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3460           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3461           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3462                && TREE_CODE (expr) != NOP_EXPR))
3463         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3464
3465       ovalue = value;
3466       value = convert (type, value);
3467
3468       /* Ignore any integer overflow caused by the cast.  */
3469       if (TREE_CODE (value) == INTEGER_CST)
3470         {
3471           if (CONSTANT_CLASS_P (ovalue)
3472               && (TREE_OVERFLOW (ovalue) || TREE_CONSTANT_OVERFLOW (ovalue)))
3473             {
3474               /* Avoid clobbering a shared constant.  */
3475               value = copy_node (value);
3476               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3477               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3478             }
3479           else if (TREE_OVERFLOW (value) || TREE_CONSTANT_OVERFLOW (value))
3480             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3481             value = build_int_cst_wide (TREE_TYPE (value),
3482                                         TREE_INT_CST_LOW (value),
3483                                         TREE_INT_CST_HIGH (value));
3484         }
3485     }
3486
3487   /* Don't let a cast be an lvalue.  */
3488   if (value == expr)
3489     value = non_lvalue (value);
3490
3491   return value;
3492 }
3493
3494 /* Interpret a cast of expression EXPR to type TYPE.  */
3495 tree
3496 c_cast_expr (struct c_type_name *type_name, tree expr)
3497 {
3498   tree type;
3499   int saved_wsp = warn_strict_prototypes;
3500
3501   /* This avoids warnings about unprototyped casts on
3502      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3503   if (TREE_CODE (expr) == INTEGER_CST)
3504     warn_strict_prototypes = 0;
3505   type = groktypename (type_name);
3506   warn_strict_prototypes = saved_wsp;
3507
3508   return build_c_cast (type, expr);
3509 }
3510
3511 \f
3512 /* Build an assignment expression of lvalue LHS from value RHS.
3513    MODIFYCODE is the code for a binary operator that we use
3514    to combine the old value of LHS with RHS to get the new value.
3515    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3516
3517 tree
3518 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3519 {
3520   tree result;
3521   tree newrhs;
3522   tree lhstype = TREE_TYPE (lhs);
3523   tree olhstype = lhstype;
3524
3525   /* Types that aren't fully specified cannot be used in assignments.  */
3526   lhs = require_complete_type (lhs);
3527
3528   /* Avoid duplicate error messages from operands that had errors.  */
3529   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3530     return error_mark_node;
3531
3532   STRIP_TYPE_NOPS (rhs);
3533
3534   newrhs = rhs;
3535
3536   /* If a binary op has been requested, combine the old LHS value with the RHS
3537      producing the value we should actually store into the LHS.  */
3538
3539   if (modifycode != NOP_EXPR)
3540     {
3541       lhs = stabilize_reference (lhs);
3542       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3543     }
3544
3545   if (!lvalue_or_else (lhs, lv_assign))
3546     return error_mark_node;
3547
3548   /* Give an error for storing in something that is 'const'.  */
3549
3550   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3551       || ((TREE_CODE (lhstype) == RECORD_TYPE
3552            || TREE_CODE (lhstype) == UNION_TYPE)
3553           && C_TYPE_FIELDS_READONLY (lhstype)))
3554     readonly_error (lhs, lv_assign);
3555
3556   /* If storing into a structure or union member,
3557      it has probably been given type `int'.
3558      Compute the type that would go with
3559      the actual amount of storage the member occupies.  */
3560
3561   if (TREE_CODE (lhs) == COMPONENT_REF
3562       && (TREE_CODE (lhstype) == INTEGER_TYPE
3563           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3564           || TREE_CODE (lhstype) == REAL_TYPE
3565           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3566     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3567
3568   /* If storing in a field that is in actuality a short or narrower than one,
3569      we must store in the field in its actual type.  */
3570
3571   if (lhstype != TREE_TYPE (lhs))
3572     {
3573       lhs = copy_node (lhs);
3574       TREE_TYPE (lhs) = lhstype;
3575     }
3576
3577   /* Convert new value to destination type.  */
3578
3579   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3580                                    NULL_TREE, NULL_TREE, 0);
3581   if (TREE_CODE (newrhs) == ERROR_MARK)
3582     return error_mark_node;
3583
3584   /* Emit ObjC write barrier, if necessary.  */
3585   if (c_dialect_objc () && flag_objc_gc)
3586     {
3587       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3588       if (result)
3589         return result;
3590     }
3591
3592   /* Scan operands.  */
3593
3594   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3595   TREE_SIDE_EFFECTS (result) = 1;
3596
3597   /* If we got the LHS in a different type for storing in,
3598      convert the result back to the nominal type of LHS
3599      so that the value we return always has the same type
3600      as the LHS argument.  */
3601
3602   if (olhstype == TREE_TYPE (result))
3603     return result;
3604   return convert_for_assignment (olhstype, result, ic_assign,
3605                                  NULL_TREE, NULL_TREE, 0);
3606 }
3607 \f
3608 /* Convert value RHS to type TYPE as preparation for an assignment
3609    to an lvalue of type TYPE.
3610    The real work of conversion is done by `convert'.
3611    The purpose of this function is to generate error messages
3612    for assignments that are not allowed in C.
3613    ERRTYPE says whether it is argument passing, assignment,
3614    initialization or return.
3615
3616    FUNCTION is a tree for the function being called.
3617    PARMNUM is the number of the argument, for printing in error messages.  */
3618
3619 static tree
3620 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3621                         tree fundecl, tree function, int parmnum)
3622 {
3623   enum tree_code codel = TREE_CODE (type);
3624   tree rhstype;
3625   enum tree_code coder;
3626   tree rname = NULL_TREE;
3627   bool objc_ok = false;
3628
3629   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3630     {
3631       tree selector;
3632       /* Change pointer to function to the function itself for
3633          diagnostics.  */
3634       if (TREE_CODE (function) == ADDR_EXPR
3635           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3636         function = TREE_OPERAND (function, 0);
3637
3638       /* Handle an ObjC selector specially for diagnostics.  */
3639       selector = objc_message_selector ();
3640       rname = function;
3641       if (selector && parmnum > 2)
3642         {
3643           rname = selector;
3644           parmnum -= 2;
3645         }
3646     }
3647
3648   /* This macro is used to emit diagnostics to ensure that all format
3649      strings are complete sentences, visible to gettext and checked at
3650      compile time.  */
3651 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3652   do {                                          \
3653     switch (errtype)                            \
3654       {                                         \
3655       case ic_argpass:                          \
3656         pedwarn (AR, parmnum, rname);           \
3657         break;                                  \
3658       case ic_argpass_nonproto:                 \
3659         warning (0, AR, parmnum, rname);                \
3660         break;                                  \
3661       case ic_assign:                           \
3662         pedwarn (AS);                           \
3663         break;                                  \
3664       case ic_init:                             \
3665         pedwarn (IN);                           \
3666         break;                                  \
3667       case ic_return:                           \
3668         pedwarn (RE);                           \
3669         break;                                  \
3670       default:                                  \
3671         gcc_unreachable ();                     \
3672       }                                         \
3673   } while (0)
3674
3675   STRIP_TYPE_NOPS (rhs);
3676
3677   if (optimize && TREE_CODE (rhs) == VAR_DECL
3678            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3679     rhs = decl_constant_value_for_broken_optimization (rhs);
3680
3681   rhstype = TREE_TYPE (rhs);
3682   coder = TREE_CODE (rhstype);
3683
3684   if (coder == ERROR_MARK)
3685     return error_mark_node;
3686
3687   if (c_dialect_objc ())
3688     {
3689       int parmno;
3690
3691       switch (errtype)
3692         {
3693         case ic_return:
3694           parmno = 0;
3695           break;
3696
3697         case ic_assign:
3698           parmno = -1;
3699           break;
3700
3701         case ic_init:
3702           parmno = -2;
3703           break;
3704
3705         default:
3706           parmno = parmnum;
3707           break;
3708         }
3709
3710       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3711     }
3712
3713   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3714     {
3715       overflow_warning (rhs);
3716       return rhs;
3717     }
3718
3719   if (coder == VOID_TYPE)
3720     {
3721       /* Except for passing an argument to an unprototyped function,
3722          this is a constraint violation.  When passing an argument to
3723          an unprototyped function, it is compile-time undefined;
3724          making it a constraint in that case was rejected in
3725          DR#252.  */
3726       error ("void value not ignored as it ought to be");
3727       return error_mark_node;
3728     }
3729   /* A type converts to a reference to it.
3730      This code doesn't fully support references, it's just for the
3731      special case of va_start and va_copy.  */
3732   if (codel == REFERENCE_TYPE
3733       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3734     {
3735       if (!lvalue_p (rhs))
3736         {
3737           error ("cannot pass rvalue to reference parameter");
3738           return error_mark_node;
3739         }
3740       if (!c_mark_addressable (rhs))
3741         return error_mark_node;
3742       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3743
3744       /* We already know that these two types are compatible, but they
3745          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3746          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3747          likely to be va_list, a typedef to __builtin_va_list, which
3748          is different enough that it will cause problems later.  */
3749       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3750         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3751
3752       rhs = build1 (NOP_EXPR, type, rhs);
3753       return rhs;
3754     }
3755   /* Some types can interconvert without explicit casts.  */
3756   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3757            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3758     return convert (type, rhs);
3759   /* Arithmetic types all interconvert, and enum is treated like int.  */
3760   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3761             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3762             || codel == BOOLEAN_TYPE)
3763            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3764                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3765                || coder == BOOLEAN_TYPE))
3766     return convert_and_check (type, rhs);
3767
3768   /* Conversion to a transparent union from its member types.
3769      This applies only to function arguments.  */
3770   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3771            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3772     {
3773       tree memb, marginal_memb = NULL_TREE;
3774
3775       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3776         {
3777           tree memb_type = TREE_TYPE (memb);
3778
3779           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3780                          TYPE_MAIN_VARIANT (rhstype)))
3781             break;
3782
3783           if (TREE_CODE (memb_type) != POINTER_TYPE)
3784             continue;
3785
3786           if (coder == POINTER_TYPE)
3787             {
3788               tree ttl = TREE_TYPE (memb_type);
3789               tree ttr = TREE_TYPE (rhstype);
3790
3791               /* Any non-function converts to a [const][volatile] void *
3792                  and vice versa; otherwise, targets must be the same.
3793                  Meanwhile, the lhs target must have all the qualifiers of
3794                  the rhs.  */
3795               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3796                   || comp_target_types (memb_type, rhstype))
3797                 {
3798                   /* If this type won't generate any warnings, use it.  */
3799                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3800                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3801                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3802                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3803                              == TYPE_QUALS (ttr))
3804                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3805                              == TYPE_QUALS (ttl))))
3806                     break;
3807
3808                   /* Keep looking for a better type, but remember this one.  */
3809                   if (!marginal_memb)
3810                     marginal_memb = memb;
3811                 }
3812             }
3813
3814           /* Can convert integer zero to any pointer type.  */
3815           if (integer_zerop (rhs)
3816               || (TREE_CODE (rhs) == NOP_EXPR
3817                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3818             {
3819               rhs = null_pointer_node;
3820               break;
3821             }
3822         }
3823
3824       if (memb || marginal_memb)
3825         {
3826           if (!memb)
3827             {
3828               /* We have only a marginally acceptable member type;
3829                  it needs a warning.  */
3830               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3831               tree ttr = TREE_TYPE (rhstype);
3832
3833               /* Const and volatile mean something different for function
3834                  types, so the usual warnings are not appropriate.  */
3835               if (TREE_CODE (ttr) == FUNCTION_TYPE
3836                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3837                 {
3838                   /* Because const and volatile on functions are
3839                      restrictions that say the function will not do
3840                      certain things, it is okay to use a const or volatile
3841                      function where an ordinary one is wanted, but not
3842                      vice-versa.  */
3843                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3844                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3845                                             "makes qualified function "
3846                                             "pointer from unqualified"),
3847                                          G_("assignment makes qualified "
3848                                             "function pointer from "
3849                                             "unqualified"),
3850                                          G_("initialization makes qualified "
3851                                             "function pointer from "
3852                                             "unqualified"),
3853                                          G_("return makes qualified function "
3854                                             "pointer from unqualified"));
3855                 }
3856               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3857                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3858                                         "qualifiers from pointer target type"),
3859                                      G_("assignment discards qualifiers "
3860                                         "from pointer target type"),
3861                                      G_("initialization discards qualifiers "
3862                                         "from pointer target type"),
3863                                      G_("return discards qualifiers from "
3864                                         "pointer target type"));
3865
3866               memb = marginal_memb;
3867             }
3868
3869           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3870             pedwarn ("ISO C prohibits argument conversion to union type");
3871
3872           return build_constructor_single (type, memb, rhs);
3873         }
3874     }
3875
3876   /* Conversions among pointers */
3877   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3878            && (coder == codel))
3879     {
3880       tree ttl = TREE_TYPE (type);
3881       tree ttr = TREE_TYPE (rhstype);
3882       tree mvl = ttl;
3883       tree mvr = ttr;
3884       bool is_opaque_pointer;
3885       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3886
3887       if (TREE_CODE (mvl) != ARRAY_TYPE)
3888         mvl = TYPE_MAIN_VARIANT (mvl);
3889       if (TREE_CODE (mvr) != ARRAY_TYPE)
3890         mvr = TYPE_MAIN_VARIANT (mvr);
3891       /* Opaque pointers are treated like void pointers.  */
3892       is_opaque_pointer = (targetm.vector_opaque_p (type)
3893                            || targetm.vector_opaque_p (rhstype))
3894         && TREE_CODE (ttl) == VECTOR_TYPE
3895         && TREE_CODE (ttr) == VECTOR_TYPE;
3896
3897       /* C++ does not allow the implicit conversion void* -> T*.  However,
3898          for the purpose of reducing the number of false positives, we
3899          tolerate the special case of
3900
3901                 int *p = NULL;
3902
3903          where NULL is typically defined in C to be '(void *) 0'.  */
3904       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3905         warning (OPT_Wc___compat, "request for implicit conversion from "
3906                  "%qT to %qT not permitted in C++", rhstype, type);
3907
3908       /* Check if the right-hand side has a format attribute but the
3909          left-hand side doesn't.  */
3910       if (warn_missing_format_attribute
3911           && check_missing_format_attribute (type, rhstype))
3912         {
3913           switch (errtype)
3914           {
3915           case ic_argpass:
3916           case ic_argpass_nonproto:
3917             warning (OPT_Wmissing_format_attribute,
3918                      "argument %d of %qE might be "
3919                      "a candidate for a format attribute",
3920                      parmnum, rname);
3921             break;
3922           case ic_assign:
3923             warning (OPT_Wmissing_format_attribute,
3924                      "assignment left-hand side might be "
3925                      "a candidate for a format attribute");
3926             break;
3927           case ic_init:
3928             warning (OPT_Wmissing_format_attribute,
3929                      "initialization left-hand side might be "
3930                      "a candidate for a format attribute");
3931             break;
3932           case ic_return:
3933             warning (OPT_Wmissing_format_attribute,
3934                      "return type might be "
3935                      "a candidate for a format attribute");
3936             break;
3937           default:
3938             gcc_unreachable ();
3939           }
3940         }
3941
3942       /* Any non-function converts to a [const][volatile] void *
3943          and vice versa; otherwise, targets must be the same.
3944          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3945       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3946           || (target_cmp = comp_target_types (type, rhstype))
3947           || is_opaque_pointer
3948           || (c_common_unsigned_type (mvl)
3949               == c_common_unsigned_type (mvr)))
3950         {
3951           if (pedantic
3952               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3953                   ||
3954                   (VOID_TYPE_P (ttr)
3955                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3956                       which are not ANSI null ptr constants.  */
3957                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3958                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3959             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3960                                     "%qE between function pointer "
3961                                     "and %<void *%>"),
3962                                  G_("ISO C forbids assignment between "
3963                                     "function pointer and %<void *%>"),
3964                                  G_("ISO C forbids initialization between "
3965                                     "function pointer and %<void *%>"),
3966                                  G_("ISO C forbids return between function "
3967                                     "pointer and %<void *%>"));
3968           /* Const and volatile mean something different for function types,
3969              so the usual warnings are not appropriate.  */
3970           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3971                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3972             {
3973               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3974                 {
3975                   /* Types differing only by the presence of the 'volatile'
3976                      qualifier are acceptable if the 'volatile' has been added
3977                      in by the Objective-C EH machinery.  */
3978                   if (!objc_type_quals_match (ttl, ttr))
3979                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3980                                             "qualifiers from pointer target type"),
3981                                          G_("assignment discards qualifiers "
3982                                             "from pointer target type"),
3983                                          G_("initialization discards qualifiers "
3984                                             "from pointer target type"),
3985                                          G_("return discards qualifiers from "
3986                                             "pointer target type"));
3987                 }
3988               /* If this is not a case of ignoring a mismatch in signedness,
3989                  no warning.  */
3990               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3991                        || target_cmp)
3992                 ;
3993               /* If there is a mismatch, do warn.  */
3994               else if (warn_pointer_sign)
3995                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
3996                                         "%d of %qE differ in signedness"),
3997                                      G_("pointer targets in assignment "
3998                                         "differ in signedness"),
3999                                      G_("pointer targets in initialization "
4000                                         "differ in signedness"),
4001                                      G_("pointer targets in return differ "
4002                                         "in signedness"));
4003             }
4004           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4005                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4006             {
4007               /* Because const and volatile on functions are restrictions
4008                  that say the function will not do certain things,
4009                  it is okay to use a const or volatile function
4010                  where an ordinary one is wanted, but not vice-versa.  */
4011               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4012                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4013                                         "qualified function pointer "
4014                                         "from unqualified"),
4015                                      G_("assignment makes qualified function "
4016                                         "pointer from unqualified"),
4017                                      G_("initialization makes qualified "
4018                                         "function pointer from unqualified"),
4019                                      G_("return makes qualified function "
4020                                         "pointer from unqualified"));
4021             }
4022         }
4023       else
4024         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4025         if (!objc_ok)
4026           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4027                                   "incompatible pointer type"),
4028                                G_("assignment from incompatible pointer type"),
4029                                G_("initialization from incompatible "
4030                                   "pointer type"),
4031                                G_("return from incompatible pointer type"));
4032
4033       return convert (type, rhs);
4034     }
4035   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4036     {
4037       /* ??? This should not be an error when inlining calls to
4038          unprototyped functions.  */
4039       error ("invalid use of non-lvalue array");
4040       return error_mark_node;
4041     }
4042   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4043     {
4044       /* An explicit constant 0 can convert to a pointer,
4045          or one that results from arithmetic, even including
4046          a cast to integer type.  */
4047       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
4048           &&
4049           !(TREE_CODE (rhs) == NOP_EXPR
4050             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
4051             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
4052             && integer_zerop (TREE_OPERAND (rhs, 0))))
4053         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4054                                 "pointer from integer without a cast"),
4055                              G_("assignment makes pointer from integer "
4056                                 "without a cast"),
4057                              G_("initialization makes pointer from "
4058                                 "integer without a cast"),
4059                              G_("return makes pointer from integer "
4060                                 "without a cast"));
4061
4062       return convert (type, rhs);
4063     }
4064   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4065     {
4066       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4067                               "from pointer without a cast"),
4068                            G_("assignment makes integer from pointer "
4069                               "without a cast"),
4070                            G_("initialization makes integer from pointer "
4071                               "without a cast"),
4072                            G_("return makes integer from pointer "
4073                               "without a cast"));
4074       return convert (type, rhs);
4075     }
4076   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4077     return convert (type, rhs);
4078
4079   switch (errtype)
4080     {
4081     case ic_argpass:
4082     case ic_argpass_nonproto:
4083       /* ??? This should not be an error when inlining calls to
4084          unprototyped functions.  */
4085       error ("incompatible type for argument %d of %qE", parmnum, rname);
4086       break;
4087     case ic_assign:
4088       error ("incompatible types in assignment");
4089       break;
4090     case ic_init:
4091       error ("incompatible types in initialization");
4092       break;
4093     case ic_return:
4094       error ("incompatible types in return");
4095       break;
4096     default:
4097       gcc_unreachable ();
4098     }
4099
4100   return error_mark_node;
4101 }
4102
4103 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4104    is used for error and waring reporting and indicates which argument
4105    is being processed.  */
4106
4107 tree
4108 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4109 {
4110   tree ret, type;
4111
4112   /* If FN was prototyped, the value has been converted already
4113      in convert_arguments.  */
4114   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4115     return value;
4116
4117   type = TREE_TYPE (parm);
4118   ret = convert_for_assignment (type, value,
4119                                 ic_argpass_nonproto, fn,
4120                                 fn, argnum);
4121   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4122       && INTEGRAL_TYPE_P (type)
4123       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4124     ret = default_conversion (ret);
4125   return ret;
4126 }
4127 \f
4128 /* If VALUE is a compound expr all of whose expressions are constant, then
4129    return its value.  Otherwise, return error_mark_node.
4130
4131    This is for handling COMPOUND_EXPRs as initializer elements
4132    which is allowed with a warning when -pedantic is specified.  */
4133
4134 static tree
4135 valid_compound_expr_initializer (tree value, tree endtype)
4136 {
4137   if (TREE_CODE (value) == COMPOUND_EXPR)
4138     {
4139       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4140           == error_mark_node)
4141         return error_mark_node;
4142       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4143                                               endtype);
4144     }
4145   else if (!initializer_constant_valid_p (value, endtype))
4146     return error_mark_node;
4147   else
4148     return value;
4149 }
4150 \f
4151 /* Perform appropriate conversions on the initial value of a variable,
4152    store it in the declaration DECL,
4153    and print any error messages that are appropriate.
4154    If the init is invalid, store an ERROR_MARK.  */
4155
4156 void
4157 store_init_value (tree decl, tree init)
4158 {
4159   tree value, type;
4160
4161   /* If variable's type was invalidly declared, just ignore it.  */
4162
4163   type = TREE_TYPE (decl);
4164   if (TREE_CODE (type) == ERROR_MARK)
4165     return;
4166
4167   /* Digest the specified initializer into an expression.  */
4168
4169   value = digest_init (type, init, true, TREE_STATIC (decl));
4170
4171   /* Store the expression if valid; else report error.  */
4172
4173   if (!in_system_header
4174       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4175     warning (OPT_Wtraditional, "traditional C rejects automatic "
4176              "aggregate initialization");
4177
4178   DECL_INITIAL (decl) = value;
4179
4180   /* ANSI wants warnings about out-of-range constant initializers.  */
4181   STRIP_TYPE_NOPS (value);
4182   constant_expression_warning (value);
4183
4184   /* Check if we need to set array size from compound literal size.  */
4185   if (TREE_CODE (type) == ARRAY_TYPE
4186       && TYPE_DOMAIN (type) == 0
4187       && value != error_mark_node)
4188     {
4189       tree inside_init = init;
4190
4191       STRIP_TYPE_NOPS (inside_init);
4192       inside_init = fold (inside_init);
4193
4194       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4195         {
4196           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4197
4198           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4199             {
4200               /* For int foo[] = (int [3]){1}; we need to set array size
4201                  now since later on array initializer will be just the
4202                  brace enclosed list of the compound literal.  */
4203               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4204               layout_type (type);
4205               layout_decl (decl, 0);
4206             }
4207         }
4208     }
4209 }
4210 \f
4211 /* Methods for storing and printing names for error messages.  */
4212
4213 /* Implement a spelling stack that allows components of a name to be pushed
4214    and popped.  Each element on the stack is this structure.  */
4215
4216 struct spelling
4217 {
4218   int kind;
4219   union
4220     {
4221       int i;
4222       const char *s;
4223     } u;
4224 };
4225
4226 #define SPELLING_STRING 1
4227 #define SPELLING_MEMBER 2
4228 #define SPELLING_BOUNDS 3
4229
4230 static struct spelling *spelling;       /* Next stack element (unused).  */
4231 static struct spelling *spelling_base;  /* Spelling stack base.  */
4232 static int spelling_size;               /* Size of the spelling stack.  */
4233
4234 /* Macros to save and restore the spelling stack around push_... functions.
4235    Alternative to SAVE_SPELLING_STACK.  */
4236
4237 #define SPELLING_DEPTH() (spelling - spelling_base)
4238 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4239
4240 /* Push an element on the spelling stack with type KIND and assign VALUE
4241    to MEMBER.  */
4242
4243 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4244 {                                                                       \
4245   int depth = SPELLING_DEPTH ();                                        \
4246                                                                         \
4247   if (depth >= spelling_size)                                           \
4248     {                                                                   \
4249       spelling_size += 10;                                              \
4250       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4251                                   spelling_size);                       \
4252       RESTORE_SPELLING_DEPTH (depth);                                   \
4253     }                                                                   \
4254                                                                         \
4255   spelling->kind = (KIND);                                              \
4256   spelling->MEMBER = (VALUE);                                           \
4257   spelling++;                                                           \
4258 }
4259
4260 /* Push STRING on the stack.  Printed literally.  */
4261
4262 static void
4263 push_string (const char *string)
4264 {
4265   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4266 }
4267
4268 /* Push a member name on the stack.  Printed as '.' STRING.  */
4269
4270 static void
4271 push_member_name (tree decl)
4272 {
4273   const char *const string
4274     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4275   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4276 }
4277
4278 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4279
4280 static void
4281 push_array_bounds (int bounds)
4282 {
4283   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4284 }
4285
4286 /* Compute the maximum size in bytes of the printed spelling.  */
4287
4288 static int
4289 spelling_length (void)
4290 {
4291   int size = 0;
4292   struct spelling *p;
4293
4294   for (p = spelling_base; p < spelling; p++)
4295     {
4296       if (p->kind == SPELLING_BOUNDS)
4297         size += 25;
4298       else
4299         size += strlen (p->u.s) + 1;
4300     }
4301
4302   return size;
4303 }
4304
4305 /* Print the spelling to BUFFER and return it.  */
4306
4307 static char *
4308 print_spelling (char *buffer)
4309 {
4310   char *d = buffer;
4311   struct spelling *p;
4312
4313   for (p = spelling_base; p < spelling; p++)
4314     if (p->kind == SPELLING_BOUNDS)
4315       {
4316         sprintf (d, "[%d]", p->u.i);
4317         d += strlen (d);
4318       }
4319     else
4320       {
4321         const char *s;
4322         if (p->kind == SPELLING_MEMBER)
4323           *d++ = '.';
4324         for (s = p->u.s; (*d = *s++); d++)
4325           ;
4326       }
4327   *d++ = '\0';
4328   return buffer;
4329 }
4330
4331 /* Issue an error message for a bad initializer component.
4332    MSGID identifies the message.
4333    The component name is taken from the spelling stack.  */
4334
4335 void
4336 error_init (const char *msgid)
4337 {
4338   char *ofwhat;
4339
4340   error ("%s", _(msgid));
4341   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4342   if (*ofwhat)
4343     error ("(near initialization for %qs)", ofwhat);
4344 }
4345
4346 /* Issue a pedantic warning for a bad initializer component.
4347    MSGID identifies the message.
4348    The component name is taken from the spelling stack.  */
4349
4350 void
4351 pedwarn_init (const char *msgid)
4352 {
4353   char *ofwhat;
4354
4355   pedwarn ("%s", _(msgid));
4356   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4357   if (*ofwhat)
4358     pedwarn ("(near initialization for %qs)", ofwhat);
4359 }
4360
4361 /* Issue a warning for a bad initializer component.
4362    MSGID identifies the message.
4363    The component name is taken from the spelling stack.  */
4364
4365 static void
4366 warning_init (const char *msgid)
4367 {
4368   char *ofwhat;
4369
4370   warning (0, "%s", _(msgid));
4371   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4372   if (*ofwhat)
4373     warning (0, "(near initialization for %qs)", ofwhat);
4374 }
4375 \f
4376 /* If TYPE is an array type and EXPR is a parenthesized string
4377    constant, warn if pedantic that EXPR is being used to initialize an
4378    object of type TYPE.  */
4379
4380 void
4381 maybe_warn_string_init (tree type, struct c_expr expr)
4382 {
4383   if (pedantic
4384       && TREE_CODE (type) == ARRAY_TYPE
4385       && TREE_CODE (expr.value) == STRING_CST
4386       && expr.original_code != STRING_CST)
4387     pedwarn_init ("array initialized from parenthesized string constant");
4388 }
4389
4390 /* Digest the parser output INIT as an initializer for type TYPE.
4391    Return a C expression of type TYPE to represent the initial value.
4392
4393    If INIT is a string constant, STRICT_STRING is true if it is
4394    unparenthesized or we should not warn here for it being parenthesized.
4395    For other types of INIT, STRICT_STRING is not used.
4396
4397    REQUIRE_CONSTANT requests an error if non-constant initializers or
4398    elements are seen.  */
4399
4400 static tree
4401 digest_init (tree type, tree init, bool strict_string, int require_constant)
4402 {
4403   enum tree_code code = TREE_CODE (type);
4404   tree inside_init = init;
4405
4406   if (type == error_mark_node
4407       || init == error_mark_node
4408       || TREE_TYPE (init) == error_mark_node)
4409     return error_mark_node;
4410
4411   STRIP_TYPE_NOPS (inside_init);
4412
4413   inside_init = fold (inside_init);
4414
4415   /* Initialization of an array of chars from a string constant
4416      optionally enclosed in braces.  */
4417
4418   if (code == ARRAY_TYPE && inside_init
4419       && TREE_CODE (inside_init) == STRING_CST)
4420     {
4421       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4422       /* Note that an array could be both an array of character type
4423          and an array of wchar_t if wchar_t is signed char or unsigned
4424          char.  */
4425       bool char_array = (typ1 == char_type_node
4426                          || typ1 == signed_char_type_node
4427                          || typ1 == unsigned_char_type_node);
4428       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4429       if (char_array || wchar_array)
4430         {
4431           struct c_expr expr;
4432           bool char_string;
4433           expr.value = inside_init;
4434           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4435           maybe_warn_string_init (type, expr);
4436
4437           char_string
4438             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4439                == char_type_node);
4440
4441           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4442                          TYPE_MAIN_VARIANT (type)))
4443             return inside_init;
4444
4445           if (!wchar_array && !char_string)
4446             {
4447               error_init ("char-array initialized from wide string");
4448               return error_mark_node;
4449             }
4450           if (char_string && !char_array)
4451             {
4452               error_init ("wchar_t-array initialized from non-wide string");
4453               return error_mark_node;
4454             }
4455
4456           TREE_TYPE (inside_init) = type;
4457           if (TYPE_DOMAIN (type) != 0
4458               && TYPE_SIZE (type) != 0
4459               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4460               /* Subtract 1 (or sizeof (wchar_t))
4461                  because it's ok to ignore the terminating null char
4462                  that is counted in the length of the constant.  */
4463               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4464                                        TREE_STRING_LENGTH (inside_init)
4465                                        - ((TYPE_PRECISION (typ1)
4466                                            != TYPE_PRECISION (char_type_node))
4467                                           ? (TYPE_PRECISION (wchar_type_node)
4468                                              / BITS_PER_UNIT)
4469                                           : 1)))
4470             pedwarn_init ("initializer-string for array of chars is too long");
4471
4472           return inside_init;
4473         }
4474       else if (INTEGRAL_TYPE_P (typ1))
4475         {
4476           error_init ("array of inappropriate type initialized "
4477                       "from string constant");
4478           return error_mark_node;
4479         }
4480     }
4481
4482   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4483      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4484      below and handle as a constructor.  */
4485   if (code == VECTOR_TYPE
4486       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4487       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4488       && TREE_CONSTANT (inside_init))
4489     {
4490       if (TREE_CODE (inside_init) == VECTOR_CST
4491           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4492                         TYPE_MAIN_VARIANT (type)))
4493         return inside_init;
4494
4495       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4496         {
4497           unsigned HOST_WIDE_INT ix;
4498           tree value;
4499           bool constant_p = true;
4500
4501           /* Iterate through elements and check if all constructor
4502              elements are *_CSTs.  */
4503           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4504             if (!CONSTANT_CLASS_P (value))
4505               {
4506                 constant_p = false;
4507                 break;
4508               }
4509
4510           if (constant_p)
4511             return build_vector_from_ctor (type,
4512                                            CONSTRUCTOR_ELTS (inside_init));
4513         }
4514     }
4515
4516   /* Any type can be initialized
4517      from an expression of the same type, optionally with braces.  */
4518
4519   if (inside_init && TREE_TYPE (inside_init) != 0
4520       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4521                      TYPE_MAIN_VARIANT (type))
4522           || (code == ARRAY_TYPE
4523               && comptypes (TREE_TYPE (inside_init), type))
4524           || (code == VECTOR_TYPE
4525               && comptypes (TREE_TYPE (inside_init), type))
4526           || (code == POINTER_TYPE
4527               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4528               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4529                             TREE_TYPE (type)))))
4530     {
4531       if (code == POINTER_TYPE)
4532         {
4533           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4534             {
4535               if (TREE_CODE (inside_init) == STRING_CST
4536                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4537                 inside_init = array_to_pointer_conversion (inside_init);
4538               else
4539                 {
4540                   error_init ("invalid use of non-lvalue array");
4541                   return error_mark_node;
4542                 }
4543             }
4544         }
4545
4546       if (code == VECTOR_TYPE)
4547         /* Although the types are compatible, we may require a
4548            conversion.  */
4549         inside_init = convert (type, inside_init);
4550
4551       if (require_constant && !flag_isoc99
4552           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4553         {
4554           /* As an extension, allow initializing objects with static storage
4555              duration with compound literals (which are then treated just as
4556              the brace enclosed list they contain).  */
4557           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4558           inside_init = DECL_INITIAL (decl);
4559         }
4560
4561       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4562           && TREE_CODE (inside_init) != CONSTRUCTOR)
4563         {
4564           error_init ("array initialized from non-constant array expression");
4565           return error_mark_node;
4566         }
4567
4568       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4569         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4570
4571       /* Compound expressions can only occur here if -pedantic or
4572          -pedantic-errors is specified.  In the later case, we always want
4573          an error.  In the former case, we simply want a warning.  */
4574       if (require_constant && pedantic
4575           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4576         {
4577           inside_init
4578             = valid_compound_expr_initializer (inside_init,
4579                                                TREE_TYPE (inside_init));
4580           if (inside_init == error_mark_node)
4581             error_init ("initializer element is not constant");
4582           else
4583             pedwarn_init ("initializer element is not constant");
4584           if (flag_pedantic_errors)
4585             inside_init = error_mark_node;
4586         }
4587       else if (require_constant
4588                && !initializer_constant_valid_p (inside_init,
4589                                                  TREE_TYPE (inside_init)))
4590         {
4591           error_init ("initializer element is not constant");
4592           inside_init = error_mark_node;
4593         }
4594
4595       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4596       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4597         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4598                                               NULL_TREE, 0);
4599       return inside_init;
4600     }
4601
4602   /* Handle scalar types, including conversions.  */
4603
4604   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4605       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4606       || code == VECTOR_TYPE)
4607     {
4608       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4609           && (TREE_CODE (init) == STRING_CST
4610               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4611         init = array_to_pointer_conversion (init);
4612       inside_init
4613         = convert_for_assignment (type, init, ic_init,
4614                                   NULL_TREE, NULL_TREE, 0);
4615
4616       /* Check to see if we have already given an error message.  */
4617       if (inside_init == error_mark_node)
4618         ;
4619       else if (require_constant && !TREE_CONSTANT (inside_init))
4620         {
4621           error_init ("initializer element is not constant");
4622           inside_init = error_mark_node;
4623         }
4624       else if (require_constant
4625                && !initializer_constant_valid_p (inside_init,
4626                                                  TREE_TYPE (inside_init)))
4627         {
4628           error_init ("initializer element is not computable at load time");
4629           inside_init = error_mark_node;
4630         }
4631
4632       return inside_init;
4633     }
4634
4635   /* Come here only for records and arrays.  */
4636
4637   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4638     {
4639       error_init ("variable-sized object may not be initialized");
4640       return error_mark_node;
4641     }
4642
4643   error_init ("invalid initializer");
4644   return error_mark_node;
4645 }
4646 \f
4647 /* Handle initializers that use braces.  */
4648
4649 /* Type of object we are accumulating a constructor for.
4650    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4651 static tree constructor_type;
4652
4653 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4654    left to fill.  */
4655 static tree constructor_fields;
4656
4657 /* For an ARRAY_TYPE, this is the specified index
4658    at which to store the next element we get.  */
4659 static tree constructor_index;
4660
4661 /* For an ARRAY_TYPE, this is the maximum index.  */
4662 static tree constructor_max_index;
4663
4664 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4665 static tree constructor_unfilled_fields;
4666
4667 /* For an ARRAY_TYPE, this is the index of the first element
4668    not yet written out.  */
4669 static tree constructor_unfilled_index;
4670
4671 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4672    This is so we can generate gaps between fields, when appropriate.  */
4673 static tree constructor_bit_index;
4674
4675 /* If we are saving up the elements rather than allocating them,
4676    this is the list of elements so far (in reverse order,
4677    most recent first).  */
4678 static VEC(constructor_elt,gc) *constructor_elements;
4679
4680 /* 1 if constructor should be incrementally stored into a constructor chain,
4681    0 if all the elements should be kept in AVL tree.  */
4682 static int constructor_incremental;
4683
4684 /* 1 if so far this constructor's elements are all compile-time constants.  */
4685 static int constructor_constant;
4686
4687 /* 1 if so far this constructor's elements are all valid address constants.  */
4688 static int constructor_simple;
4689
4690 /* 1 if this constructor is erroneous so far.  */
4691 static int constructor_erroneous;
4692
4693 /* Structure for managing pending initializer elements, organized as an
4694    AVL tree.  */
4695
4696 struct init_node
4697 {
4698   struct init_node *left, *right;
4699   struct init_node *parent;
4700   int balance;
4701   tree purpose;
4702   tree value;
4703 };
4704
4705 /* Tree of pending elements at this constructor level.
4706    These are elements encountered out of order
4707    which belong at places we haven't reached yet in actually
4708    writing the output.
4709    Will never hold tree nodes across GC runs.  */
4710 static struct init_node *constructor_pending_elts;
4711
4712 /* The SPELLING_DEPTH of this constructor.  */
4713 static int constructor_depth;
4714
4715 /* DECL node for which an initializer is being read.
4716    0 means we are reading a constructor expression
4717    such as (struct foo) {...}.  */
4718 static tree constructor_decl;
4719
4720 /* Nonzero if this is an initializer for a top-level decl.  */
4721 static int constructor_top_level;
4722
4723 /* Nonzero if there were any member designators in this initializer.  */
4724 static int constructor_designated;
4725
4726 /* Nesting depth of designator list.  */
4727 static int designator_depth;
4728
4729 /* Nonzero if there were diagnosed errors in this designator list.  */
4730 static int designator_erroneous;
4731
4732 \f
4733 /* This stack has a level for each implicit or explicit level of
4734    structuring in the initializer, including the outermost one.  It
4735    saves the values of most of the variables above.  */
4736
4737 struct constructor_range_stack;
4738
4739 struct constructor_stack
4740 {
4741   struct constructor_stack *next;
4742   tree type;
4743   tree fields;
4744   tree index;
4745   tree max_index;
4746   tree unfilled_index;
4747   tree unfilled_fields;
4748   tree bit_index;
4749   VEC(constructor_elt,gc) *elements;
4750   struct init_node *pending_elts;
4751   int offset;
4752   int depth;
4753   /* If value nonzero, this value should replace the entire
4754      constructor at this level.  */
4755   struct c_expr replacement_value;
4756   struct constructor_range_stack *range_stack;
4757   char constant;
4758   char simple;
4759   char implicit;
4760   char erroneous;
4761   char outer;
4762   char incremental;
4763   char designated;
4764 };
4765
4766 static struct constructor_stack *constructor_stack;
4767
4768 /* This stack represents designators from some range designator up to
4769    the last designator in the list.  */
4770
4771 struct constructor_range_stack
4772 {
4773   struct constructor_range_stack *next, *prev;
4774   struct constructor_stack *stack;
4775   tree range_start;
4776   tree index;
4777   tree range_end;
4778   tree fields;
4779 };
4780
4781 static struct constructor_range_stack *constructor_range_stack;
4782
4783 /* This stack records separate initializers that are nested.
4784    Nested initializers can't happen in ANSI C, but GNU C allows them
4785    in cases like { ... (struct foo) { ... } ... }.  */
4786
4787 struct initializer_stack
4788 {
4789   struct initializer_stack *next;
4790   tree decl;
4791   struct constructor_stack *constructor_stack;
4792   struct constructor_range_stack *constructor_range_stack;
4793   VEC(constructor_elt,gc) *elements;
4794   struct spelling *spelling;
4795   struct spelling *spelling_base;
4796   int spelling_size;
4797   char top_level;
4798   char require_constant_value;
4799   char require_constant_elements;
4800 };
4801
4802 static struct initializer_stack *initializer_stack;
4803 \f
4804 /* Prepare to parse and output the initializer for variable DECL.  */
4805
4806 void
4807 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4808 {
4809   const char *locus;
4810   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4811
4812   p->decl = constructor_decl;
4813   p->require_constant_value = require_constant_value;
4814   p->require_constant_elements = require_constant_elements;
4815   p->constructor_stack = constructor_stack;
4816   p->constructor_range_stack = constructor_range_stack;
4817   p->elements = constructor_elements;
4818   p->spelling = spelling;
4819   p->spelling_base = spelling_base;
4820   p->spelling_size = spelling_size;
4821   p->top_level = constructor_top_level;
4822   p->next = initializer_stack;
4823   initializer_stack = p;
4824
4825   constructor_decl = decl;
4826   constructor_designated = 0;
4827   constructor_top_level = top_level;
4828
4829   if (decl != 0 && decl != error_mark_node)
4830     {
4831       require_constant_value = TREE_STATIC (decl);
4832       require_constant_elements
4833         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4834            /* For a scalar, you can always use any value to initialize,
4835               even within braces.  */
4836            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4837                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4838                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4839                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4840       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4841     }
4842   else
4843     {
4844       require_constant_value = 0;
4845       require_constant_elements = 0;
4846       locus = "(anonymous)";
4847     }
4848
4849   constructor_stack = 0;
4850   constructor_range_stack = 0;
4851
4852   missing_braces_mentioned = 0;
4853
4854   spelling_base = 0;
4855   spelling_size = 0;
4856   RESTORE_SPELLING_DEPTH (0);
4857
4858   if (locus)
4859     push_string (locus);
4860 }
4861
4862 void
4863 finish_init (void)
4864 {
4865   struct initializer_stack *p = initializer_stack;
4866
4867   /* Free the whole constructor stack of this initializer.  */
4868   while (constructor_stack)
4869     {
4870       struct constructor_stack *q = constructor_stack;
4871       constructor_stack = q->next;
4872       free (q);
4873     }
4874
4875   gcc_assert (!constructor_range_stack);
4876
4877   /* Pop back to the data of the outer initializer (if any).  */
4878   free (spelling_base);
4879
4880   constructor_decl = p->decl;
4881   require_constant_value = p->require_constant_value;
4882   require_constant_elements = p->require_constant_elements;
4883   constructor_stack = p->constructor_stack;
4884   constructor_range_stack = p->constructor_range_stack;
4885   constructor_elements = p->elements;
4886   spelling = p->spelling;
4887   spelling_base = p->spelling_base;
4888   spelling_size = p->spelling_size;
4889   constructor_top_level = p->top_level;
4890   initializer_stack = p->next;
4891   free (p);
4892 }
4893 \f
4894 /* Call here when we see the initializer is surrounded by braces.
4895    This is instead of a call to push_init_level;
4896    it is matched by a call to pop_init_level.
4897
4898    TYPE is the type to initialize, for a constructor expression.
4899    For an initializer for a decl, TYPE is zero.  */
4900
4901 void
4902 really_start_incremental_init (tree type)
4903 {
4904   struct constructor_stack *p = XNEW (struct constructor_stack);
4905
4906   if (type == 0)
4907     type = TREE_TYPE (constructor_decl);
4908
4909   if (targetm.vector_opaque_p (type))
4910     error ("opaque vector types cannot be initialized");
4911
4912   p->type = constructor_type;
4913   p->fields = constructor_fields;
4914   p->index = constructor_index;
4915   p->max_index = constructor_max_index;
4916   p->unfilled_index = constructor_unfilled_index;
4917   p->unfilled_fields = constructor_unfilled_fields;
4918   p->bit_index = constructor_bit_index;
4919   p->elements = constructor_elements;
4920   p->constant = constructor_constant;
4921   p->simple = constructor_simple;
4922   p->erroneous = constructor_erroneous;
4923   p->pending_elts = constructor_pending_elts;
4924   p->depth = constructor_depth;
4925   p->replacement_value.value = 0;
4926   p->replacement_value.original_code = ERROR_MARK;
4927   p->implicit = 0;
4928   p->range_stack = 0;
4929   p->outer = 0;
4930   p->incremental = constructor_incremental;
4931   p->designated = constructor_designated;
4932   p->next = 0;
4933   constructor_stack = p;
4934
4935   constructor_constant = 1;
4936   constructor_simple = 1;
4937   constructor_depth = SPELLING_DEPTH ();
4938   constructor_elements = 0;
4939   constructor_pending_elts = 0;
4940   constructor_type = type;
4941   constructor_incremental = 1;
4942   constructor_designated = 0;
4943   designator_depth = 0;
4944   designator_erroneous = 0;
4945
4946   if (TREE_CODE (constructor_type) == RECORD_TYPE
4947       || TREE_CODE (constructor_type) == UNION_TYPE)
4948     {
4949       constructor_fields = TYPE_FIELDS (constructor_type);
4950       /* Skip any nameless bit fields at the beginning.  */
4951       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4952              && DECL_NAME (constructor_fields) == 0)
4953         constructor_fields = TREE_CHAIN (constructor_fields);
4954
4955       constructor_unfilled_fields = constructor_fields;
4956       constructor_bit_index = bitsize_zero_node;
4957     }
4958   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4959     {
4960       if (TYPE_DOMAIN (constructor_type))
4961         {
4962           constructor_max_index
4963             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4964
4965           /* Detect non-empty initializations of zero-length arrays.  */
4966           if (constructor_max_index == NULL_TREE
4967               && TYPE_SIZE (constructor_type))
4968             constructor_max_index = build_int_cst (NULL_TREE, -1);
4969
4970           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4971              to initialize VLAs will cause a proper error; avoid tree
4972              checking errors as well by setting a safe value.  */
4973           if (constructor_max_index
4974               && TREE_CODE (constructor_max_index) != INTEGER_CST)
4975             constructor_max_index = build_int_cst (NULL_TREE, -1);
4976
4977           constructor_index
4978             = convert (bitsizetype,
4979                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
4980         }
4981       else
4982         {
4983           constructor_index = bitsize_zero_node;
4984           constructor_max_index = NULL_TREE;
4985         }
4986
4987       constructor_unfilled_index = constructor_index;
4988     }
4989   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
4990     {
4991       /* Vectors are like simple fixed-size arrays.  */
4992       constructor_max_index =
4993         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
4994       constructor_index = convert (bitsizetype, bitsize_zero_node);
4995       constructor_unfilled_index = constructor_index;
4996     }
4997   else
4998     {
4999       /* Handle the case of int x = {5}; */
5000       constructor_fields = constructor_type;
5001       constructor_unfilled_fields = constructor_type;
5002     }
5003 }
5004 \f
5005 /* Push down into a subobject, for initialization.
5006    If this is for an explicit set of braces, IMPLICIT is 0.
5007    If it is because the next element belongs at a lower level,
5008    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5009
5010 void
5011 push_init_level (int implicit)
5012 {
5013   struct constructor_stack *p;
5014   tree value = NULL_TREE;
5015
5016   /* If we've exhausted any levels that didn't have braces,
5017      pop them now.  If implicit == 1, this will have been done in
5018      process_init_element; do not repeat it here because in the case
5019      of excess initializers for an empty aggregate this leads to an
5020      infinite cycle of popping a level and immediately recreating
5021      it.  */
5022   if (implicit != 1)
5023     {
5024       while (constructor_stack->implicit)
5025         {
5026           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5027                || TREE_CODE (constructor_type) == UNION_TYPE)
5028               && constructor_fields == 0)
5029             process_init_element (pop_init_level (1));
5030           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5031                    && constructor_max_index
5032                    && tree_int_cst_lt (constructor_max_index,
5033                                        constructor_index))
5034             process_init_element (pop_init_level (1));
5035           else
5036             break;
5037         }
5038     }
5039
5040   /* Unless this is an explicit brace, we need to preserve previous
5041      content if any.  */
5042   if (implicit)
5043     {
5044       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5045            || TREE_CODE (constructor_type) == UNION_TYPE)
5046           && constructor_fields)
5047         value = find_init_member (constructor_fields);
5048       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5049         value = find_init_member (constructor_index);
5050     }
5051
5052   p = XNEW (struct constructor_stack);
5053   p->type = constructor_type;
5054   p->fields = constructor_fields;
5055   p->index = constructor_index;
5056   p->max_index = constructor_max_index;
5057   p->unfilled_index = constructor_unfilled_index;
5058   p->unfilled_fields = constructor_unfilled_fields;
5059   p->bit_index = constructor_bit_index;
5060   p->elements = constructor_elements;
5061   p->constant = constructor_constant;
5062   p->simple = constructor_simple;
5063   p->erroneous = constructor_erroneous;
5064   p->pending_elts = constructor_pending_elts;
5065   p->depth = constructor_depth;
5066   p->replacement_value.value = 0;
5067   p->replacement_value.original_code = ERROR_MARK;
5068   p->implicit = implicit;
5069   p->outer = 0;
5070   p->incremental = constructor_incremental;
5071   p->designated = constructor_designated;
5072   p->next = constructor_stack;
5073   p->range_stack = 0;
5074   constructor_stack = p;
5075
5076   constructor_constant = 1;
5077   constructor_simple = 1;
5078   constructor_depth = SPELLING_DEPTH ();
5079   constructor_elements = 0;
5080   constructor_incremental = 1;
5081   constructor_designated = 0;
5082   constructor_pending_elts = 0;
5083   if (!implicit)
5084     {
5085       p->range_stack = constructor_range_stack;
5086       constructor_range_stack = 0;
5087       designator_depth = 0;
5088       designator_erroneous = 0;
5089     }
5090
5091   /* Don't die if an entire brace-pair level is superfluous
5092      in the containing level.  */
5093   if (constructor_type == 0)
5094     ;
5095   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5096            || TREE_CODE (constructor_type) == UNION_TYPE)
5097     {
5098       /* Don't die if there are extra init elts at the end.  */
5099       if (constructor_fields == 0)
5100         constructor_type = 0;
5101       else
5102         {
5103           constructor_type = TREE_TYPE (constructor_fields);
5104           push_member_name (constructor_fields);
5105           constructor_depth++;
5106         }
5107     }
5108   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5109     {
5110       constructor_type = TREE_TYPE (constructor_type);
5111       push_array_bounds (tree_low_cst (constructor_index, 0));
5112       constructor_depth++;
5113     }
5114
5115   if (constructor_type == 0)
5116     {
5117       error_init ("extra brace group at end of initializer");
5118       constructor_fields = 0;
5119       constructor_unfilled_fields = 0;
5120       return;
5121     }
5122
5123   if (value && TREE_CODE (value) == CONSTRUCTOR)
5124     {
5125       constructor_constant = TREE_CONSTANT (value);
5126       constructor_simple = TREE_STATIC (value);
5127       constructor_elements = CONSTRUCTOR_ELTS (value);
5128       if (!VEC_empty (constructor_elt, constructor_elements)
5129           && (TREE_CODE (constructor_type) == RECORD_TYPE
5130               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5131         set_nonincremental_init ();
5132     }
5133
5134   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5135     {
5136       missing_braces_mentioned = 1;
5137       warning_init ("missing braces around initializer");
5138     }
5139
5140   if (TREE_CODE (constructor_type) == RECORD_TYPE
5141            || TREE_CODE (constructor_type) == UNION_TYPE)
5142     {
5143       constructor_fields = TYPE_FIELDS (constructor_type);
5144       /* Skip any nameless bit fields at the beginning.  */
5145       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5146              && DECL_NAME (constructor_fields) == 0)
5147         constructor_fields = TREE_CHAIN (constructor_fields);
5148
5149       constructor_unfilled_fields = constructor_fields;
5150       constructor_bit_index = bitsize_zero_node;
5151     }
5152   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5153     {
5154       /* Vectors are like simple fixed-size arrays.  */
5155       constructor_max_index =
5156         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5157       constructor_index = convert (bitsizetype, integer_zero_node);
5158       constructor_unfilled_index = constructor_index;
5159     }
5160   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5161     {
5162       if (TYPE_DOMAIN (constructor_type))
5163         {
5164           constructor_max_index
5165             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5166
5167           /* Detect non-empty initializations of zero-length arrays.  */
5168           if (constructor_max_index == NULL_TREE
5169               && TYPE_SIZE (constructor_type))
5170             constructor_max_index = build_int_cst (NULL_TREE, -1);
5171
5172           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5173              to initialize VLAs will cause a proper error; avoid tree
5174              checking errors as well by setting a safe value.  */
5175           if (constructor_max_index
5176               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5177             constructor_max_index = build_int_cst (NULL_TREE, -1);
5178
5179           constructor_index
5180             = convert (bitsizetype,
5181                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5182         }
5183       else
5184         constructor_index = bitsize_zero_node;
5185
5186       constructor_unfilled_index = constructor_index;
5187       if (value && TREE_CODE (value) == STRING_CST)
5188         {
5189           /* We need to split the char/wchar array into individual
5190              characters, so that we don't have to special case it
5191              everywhere.  */
5192           set_nonincremental_init_from_string (value);
5193         }
5194     }
5195   else
5196     {
5197       if (constructor_type != error_mark_node)
5198         warning_init ("braces around scalar initializer");
5199       constructor_fields = constructor_type;
5200       constructor_unfilled_fields = constructor_type;
5201     }
5202 }
5203
5204 /* At the end of an implicit or explicit brace level,
5205    finish up that level of constructor.  If a single expression
5206    with redundant braces initialized that level, return the
5207    c_expr structure for that expression.  Otherwise, the original_code
5208    element is set to ERROR_MARK.
5209    If we were outputting the elements as they are read, return 0 as the value
5210    from inner levels (process_init_element ignores that),
5211    but return error_mark_node as the value from the outermost level
5212    (that's what we want to put in DECL_INITIAL).
5213    Otherwise, return a CONSTRUCTOR expression as the value.  */
5214
5215 struct c_expr
5216 pop_init_level (int implicit)
5217 {
5218   struct constructor_stack *p;
5219   struct c_expr ret;
5220   ret.value = 0;
5221   ret.original_code = ERROR_MARK;
5222
5223   if (implicit == 0)
5224     {
5225       /* When we come to an explicit close brace,
5226          pop any inner levels that didn't have explicit braces.  */
5227       while (constructor_stack->implicit)
5228         process_init_element (pop_init_level (1));
5229
5230       gcc_assert (!constructor_range_stack);
5231     }
5232
5233   /* Now output all pending elements.  */
5234   constructor_incremental = 1;
5235   output_pending_init_elements (1);
5236
5237   p = constructor_stack;
5238
5239   /* Error for initializing a flexible array member, or a zero-length
5240      array member in an inappropriate context.  */
5241   if (constructor_type && constructor_fields
5242       && TREE_CODE (constructor_type) == ARRAY_TYPE
5243       && TYPE_DOMAIN (constructor_type)
5244       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5245     {
5246       /* Silently discard empty initializations.  The parser will
5247          already have pedwarned for empty brackets.  */
5248       if (integer_zerop (constructor_unfilled_index))
5249         constructor_type = NULL_TREE;
5250       else
5251         {
5252           gcc_assert (!TYPE_SIZE (constructor_type));
5253
5254           if (constructor_depth > 2)
5255             error_init ("initialization of flexible array member in a nested context");
5256           else if (pedantic)
5257             pedwarn_init ("initialization of a flexible array member");
5258
5259           /* We have already issued an error message for the existence
5260              of a flexible array member not at the end of the structure.
5261              Discard the initializer so that we do not die later.  */
5262           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5263             constructor_type = NULL_TREE;
5264         }
5265     }
5266
5267   /* Warn when some struct elements are implicitly initialized to zero.  */
5268   if (warn_missing_field_initializers
5269       && constructor_type
5270       && TREE_CODE (constructor_type) == RECORD_TYPE
5271       && constructor_unfilled_fields)
5272     {
5273         /* Do not warn for flexible array members or zero-length arrays.  */
5274         while (constructor_unfilled_fields
5275                && (!DECL_SIZE (constructor_unfilled_fields)
5276                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5277           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5278
5279         /* Do not warn if this level of the initializer uses member
5280            designators; it is likely to be deliberate.  */
5281         if (constructor_unfilled_fields && !constructor_designated)
5282           {
5283             push_member_name (constructor_unfilled_fields);
5284             warning_init ("missing initializer");
5285             RESTORE_SPELLING_DEPTH (constructor_depth);
5286           }
5287     }
5288
5289   /* Pad out the end of the structure.  */
5290   if (p->replacement_value.value)
5291     /* If this closes a superfluous brace pair,
5292        just pass out the element between them.  */
5293     ret = p->replacement_value;
5294   else if (constructor_type == 0)
5295     ;
5296   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5297            && TREE_CODE (constructor_type) != UNION_TYPE
5298            && TREE_CODE (constructor_type) != ARRAY_TYPE
5299            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5300     {
5301       /* A nonincremental scalar initializer--just return
5302          the element, after verifying there is just one.  */
5303       if (VEC_empty (constructor_elt,constructor_elements))
5304         {
5305           if (!constructor_erroneous)
5306             error_init ("empty scalar initializer");
5307           ret.value = error_mark_node;
5308         }
5309       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5310         {
5311           error_init ("extra elements in scalar initializer");
5312           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5313         }
5314       else
5315         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5316     }
5317   else
5318     {
5319       if (constructor_erroneous)
5320         ret.value = error_mark_node;
5321       else
5322         {
5323           ret.value = build_constructor (constructor_type,
5324                                          constructor_elements);
5325           if (constructor_constant)
5326             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5327           if (constructor_constant && constructor_simple)
5328             TREE_STATIC (ret.value) = 1;
5329         }
5330     }
5331
5332   constructor_type = p->type;
5333   constructor_fields = p->fields;
5334   constructor_index = p->index;
5335   constructor_max_index = p->max_index;
5336   constructor_unfilled_index = p->unfilled_index;
5337   constructor_unfilled_fields = p->unfilled_fields;
5338   constructor_bit_index = p->bit_index;
5339   constructor_elements = p->elements;
5340   constructor_constant = p->constant;
5341   constructor_simple = p->simple;
5342   constructor_erroneous = p->erroneous;
5343   constructor_incremental = p->incremental;
5344   constructor_designated = p->designated;
5345   constructor_pending_elts = p->pending_elts;
5346   constructor_depth = p->depth;
5347   if (!p->implicit)
5348     constructor_range_stack = p->range_stack;
5349   RESTORE_SPELLING_DEPTH (constructor_depth);
5350
5351   constructor_stack = p->next;
5352   free (p);
5353
5354   if (ret.value == 0)
5355     {
5356       if (constructor_stack == 0)
5357         {
5358           ret.value = error_mark_node;
5359           return ret;
5360         }
5361       return ret;
5362     }
5363   return ret;
5364 }
5365
5366 /* Common handling for both array range and field name designators.
5367    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5368
5369 static int
5370 set_designator (int array)
5371 {
5372   tree subtype;
5373   enum tree_code subcode;
5374
5375   /* Don't die if an entire brace-pair level is superfluous
5376      in the containing level.  */
5377   if (constructor_type == 0)
5378     return 1;
5379
5380   /* If there were errors in this designator list already, bail out
5381      silently.  */
5382   if (designator_erroneous)
5383     return 1;
5384
5385   if (!designator_depth)
5386     {
5387       gcc_assert (!constructor_range_stack);
5388
5389       /* Designator list starts at the level of closest explicit
5390          braces.  */
5391       while (constructor_stack->implicit)
5392         process_init_element (pop_init_level (1));
5393       constructor_designated = 1;
5394       return 0;
5395     }
5396
5397   switch (TREE_CODE (constructor_type))
5398     {
5399     case  RECORD_TYPE:
5400     case  UNION_TYPE:
5401       subtype = TREE_TYPE (constructor_fields);
5402       if (subtype != error_mark_node)
5403         subtype = TYPE_MAIN_VARIANT (subtype);
5404       break;
5405     case ARRAY_TYPE:
5406       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5407       break;
5408     default:
5409       gcc_unreachable ();
5410     }
5411
5412   subcode = TREE_CODE (subtype);
5413   if (array && subcode != ARRAY_TYPE)
5414     {
5415       error_init ("array index in non-array initializer");
5416       return 1;
5417     }
5418   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5419     {
5420       error_init ("field name not in record or union initializer");
5421       return 1;
5422     }
5423
5424   constructor_designated = 1;
5425   push_init_level (2);
5426   return 0;
5427 }
5428
5429 /* If there are range designators in designator list, push a new designator
5430    to constructor_range_stack.  RANGE_END is end of such stack range or
5431    NULL_TREE if there is no range designator at this level.  */
5432
5433 static void
5434 push_range_stack (tree range_end)
5435 {
5436   struct constructor_range_stack *p;
5437
5438   p = GGC_NEW (struct constructor_range_stack);
5439   p->prev = constructor_range_stack;
5440   p->next = 0;
5441   p->fields = constructor_fields;
5442   p->range_start = constructor_index;
5443   p->index = constructor_index;
5444   p->stack = constructor_stack;
5445   p->range_end = range_end;
5446   if (constructor_range_stack)
5447     constructor_range_stack->next = p;
5448   constructor_range_stack = p;
5449 }
5450
5451 /* Within an array initializer, specify the next index to be initialized.
5452    FIRST is that index.  If LAST is nonzero, then initialize a range
5453    of indices, running from FIRST through LAST.  */
5454
5455 void
5456 set_init_index (tree first, tree last)
5457 {
5458   if (set_designator (1))
5459     return;
5460
5461   designator_erroneous = 1;
5462
5463   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5464       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5465     {
5466       error_init ("array index in initializer not of integer type");
5467       return;
5468     }
5469
5470   if (TREE_CODE (first) != INTEGER_CST)
5471     error_init ("nonconstant array index in initializer");
5472   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5473     error_init ("nonconstant array index in initializer");
5474   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5475     error_init ("array index in non-array initializer");
5476   else if (tree_int_cst_sgn (first) == -1)
5477     error_init ("array index in initializer exceeds array bounds");
5478   else if (constructor_max_index
5479            && tree_int_cst_lt (constructor_max_index, first))
5480     error_init ("array index in initializer exceeds array bounds");
5481   else
5482     {
5483       constructor_index = convert (bitsizetype, first);
5484
5485       if (last)
5486         {
5487           if (tree_int_cst_equal (first, last))
5488             last = 0;
5489           else if (tree_int_cst_lt (last, first))
5490             {
5491               error_init ("empty index range in initializer");
5492               last = 0;
5493             }
5494           else
5495             {
5496               last = convert (bitsizetype, last);
5497               if (constructor_max_index != 0
5498                   && tree_int_cst_lt (constructor_max_index, last))
5499                 {
5500                   error_init ("array index range in initializer exceeds array bounds");
5501                   last = 0;
5502                 }
5503             }
5504         }
5505
5506       designator_depth++;
5507       designator_erroneous = 0;
5508       if (constructor_range_stack || last)
5509         push_range_stack (last);
5510     }
5511 }
5512
5513 /* Within a struct initializer, specify the next field to be initialized.  */
5514
5515 void
5516 set_init_label (tree fieldname)
5517 {
5518   tree tail;
5519
5520   if (set_designator (0))
5521     return;
5522
5523   designator_erroneous = 1;
5524
5525   if (TREE_CODE (constructor_type) != RECORD_TYPE
5526       && TREE_CODE (constructor_type) != UNION_TYPE)
5527     {
5528       error_init ("field name not in record or union initializer");
5529       return;
5530     }
5531
5532   for (tail = TYPE_FIELDS (constructor_type); tail;
5533        tail = TREE_CHAIN (tail))
5534     {
5535       if (DECL_NAME (tail) == fieldname)
5536         break;
5537     }
5538
5539   if (tail == 0)
5540     error ("unknown field %qE specified in initializer", fieldname);
5541   else
5542     {
5543       constructor_fields = tail;
5544       designator_depth++;
5545       designator_erroneous = 0;
5546       if (constructor_range_stack)
5547         push_range_stack (NULL_TREE);
5548     }
5549 }
5550 \f
5551 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5552    identifies the initializer, either array index or field in a structure.
5553    VALUE is the value of that index or field.  */
5554
5555 static void
5556 add_pending_init (tree purpose, tree value)
5557 {
5558   struct init_node *p, **q, *r;
5559
5560   q = &constructor_pending_elts;
5561   p = 0;
5562
5563   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5564     {
5565       while (*q != 0)
5566         {
5567           p = *q;
5568           if (tree_int_cst_lt (purpose, p->purpose))
5569             q = &p->left;
5570           else if (tree_int_cst_lt (p->purpose, purpose))
5571             q = &p->right;
5572           else
5573             {
5574               if (TREE_SIDE_EFFECTS (p->value))
5575                 warning_init ("initialized field with side-effects overwritten");
5576               p->value = value;
5577               return;
5578             }
5579         }
5580     }
5581   else
5582     {
5583       tree bitpos;
5584
5585       bitpos = bit_position (purpose);
5586       while (*q != NULL)
5587         {
5588           p = *q;
5589           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5590             q = &p->left;
5591           else if (p->purpose != purpose)
5592             q = &p->right;
5593           else
5594             {
5595               if (TREE_SIDE_EFFECTS (p->value))
5596                 warning_init ("initialized field with side-effects overwritten");
5597               p->value = value;
5598               return;
5599             }
5600         }
5601     }
5602
5603   r = GGC_NEW (struct init_node);
5604   r->purpose = purpose;
5605   r->value = value;
5606
5607   *q = r;
5608   r->parent = p;
5609   r->left = 0;
5610   r->right = 0;
5611   r->balance = 0;
5612
5613   while (p)
5614     {
5615       struct init_node *s;
5616
5617       if (r == p->left)
5618         {
5619           if (p->balance == 0)
5620             p->balance = -1;
5621           else if (p->balance < 0)
5622             {
5623               if (r->balance < 0)
5624                 {
5625                   /* L rotation.  */
5626                   p->left = r->right;
5627                   if (p->left)
5628                     p->left->parent = p;
5629                   r->right = p;
5630
5631                   p->balance = 0;
5632                   r->balance = 0;
5633
5634                   s = p->parent;
5635                   p->parent = r;
5636                   r->parent = s;
5637                   if (s)
5638                     {
5639                       if (s->left == p)
5640                         s->left = r;
5641                       else
5642                         s->right = r;
5643                     }
5644                   else
5645                     constructor_pending_elts = r;
5646                 }
5647               else
5648                 {
5649                   /* LR rotation.  */
5650                   struct init_node *t = r->right;
5651
5652                   r->right = t->left;
5653                   if (r->right)
5654                     r->right->parent = r;
5655                   t->left = r;
5656
5657                   p->left = t->right;
5658                   if (p->left)
5659                     p->left->parent = p;
5660                   t->right = p;
5661
5662                   p->balance = t->balance < 0;
5663                   r->balance = -(t->balance > 0);
5664                   t->balance = 0;
5665
5666                   s = p->parent;
5667                   p->parent = t;
5668                   r->parent = t;
5669                   t->parent = s;
5670                   if (s)
5671                     {
5672                       if (s->left == p)
5673                         s->left = t;
5674                       else
5675                         s->right = t;
5676                     }
5677                   else
5678                     constructor_pending_elts = t;
5679                 }
5680               break;
5681             }
5682           else
5683             {
5684               /* p->balance == +1; growth of left side balances the node.  */
5685               p->balance = 0;
5686               break;
5687             }
5688         }
5689       else /* r == p->right */
5690         {
5691           if (p->balance == 0)
5692             /* Growth propagation from right side.  */
5693             p->balance++;
5694           else if (p->balance > 0)
5695             {
5696               if (r->balance > 0)
5697                 {
5698                   /* R rotation.  */
5699                   p->right = r->left;
5700                   if (p->right)
5701                     p->right->parent = p;
5702                   r->left = p;
5703
5704                   p->balance = 0;
5705                   r->balance = 0;
5706
5707                   s = p->parent;
5708                   p->parent = r;
5709                   r->parent = s;
5710                   if (s)
5711                     {
5712                       if (s->left == p)
5713                         s->left = r;
5714                       else
5715                         s->right = r;
5716                     }
5717                   else
5718                     constructor_pending_elts = r;
5719                 }
5720               else /* r->balance == -1 */
5721                 {
5722                   /* RL rotation */
5723                   struct init_node *t = r->left;
5724
5725                   r->left = t->right;
5726                   if (r->left)
5727                     r->left->parent = r;
5728                   t->right = r;
5729
5730                   p->right = t->left;
5731                   if (p->right)
5732                     p->right->parent = p;
5733                   t->left = p;
5734
5735                   r->balance = (t->balance < 0);
5736                   p->balance = -(t->balance > 0);
5737                   t->balance = 0;
5738
5739                   s = p->parent;
5740                   p->parent = t;
5741                   r->parent = t;
5742                   t->parent = s;
5743                   if (s)
5744                     {
5745                       if (s->left == p)
5746                         s->left = t;
5747                       else
5748                         s->right = t;
5749                     }
5750                   else
5751                     constructor_pending_elts = t;
5752                 }
5753               break;
5754             }
5755           else
5756             {
5757               /* p->balance == -1; growth of right side balances the node.  */
5758               p->balance = 0;
5759               break;
5760             }
5761         }
5762
5763       r = p;
5764       p = p->parent;
5765     }
5766 }
5767
5768 /* Build AVL tree from a sorted chain.  */
5769
5770 static void
5771 set_nonincremental_init (void)
5772 {
5773   unsigned HOST_WIDE_INT ix;
5774   tree index, value;
5775
5776   if (TREE_CODE (constructor_type) != RECORD_TYPE
5777       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5778     return;
5779
5780   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5781     add_pending_init (index, value);
5782   constructor_elements = 0;
5783   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5784     {
5785       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5786       /* Skip any nameless bit fields at the beginning.  */
5787       while (constructor_unfilled_fields != 0
5788              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5789              && DECL_NAME (constructor_unfilled_fields) == 0)
5790         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5791
5792     }
5793   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5794     {
5795       if (TYPE_DOMAIN (constructor_type))
5796         constructor_unfilled_index
5797             = convert (bitsizetype,
5798                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5799       else
5800         constructor_unfilled_index = bitsize_zero_node;
5801     }
5802   constructor_incremental = 0;
5803 }
5804
5805 /* Build AVL tree from a string constant.  */
5806
5807 static void
5808 set_nonincremental_init_from_string (tree str)
5809 {
5810   tree value, purpose, type;
5811   HOST_WIDE_INT val[2];
5812   const char *p, *end;
5813   int byte, wchar_bytes, charwidth, bitpos;
5814
5815   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5816
5817   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5818       == TYPE_PRECISION (char_type_node))
5819     wchar_bytes = 1;
5820   else
5821     {
5822       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5823                   == TYPE_PRECISION (wchar_type_node));
5824       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5825     }
5826   charwidth = TYPE_PRECISION (char_type_node);
5827   type = TREE_TYPE (constructor_type);
5828   p = TREE_STRING_POINTER (str);
5829   end = p + TREE_STRING_LENGTH (str);
5830
5831   for (purpose = bitsize_zero_node;
5832        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5833        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5834     {
5835       if (wchar_bytes == 1)
5836         {
5837           val[1] = (unsigned char) *p++;
5838           val[0] = 0;
5839         }
5840       else
5841         {
5842           val[0] = 0;
5843           val[1] = 0;
5844           for (byte = 0; byte < wchar_bytes; byte++)
5845             {
5846               if (BYTES_BIG_ENDIAN)
5847                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5848               else
5849                 bitpos = byte * charwidth;
5850               val[bitpos < HOST_BITS_PER_WIDE_INT]
5851                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5852                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5853             }
5854         }
5855
5856       if (!TYPE_UNSIGNED (type))
5857         {
5858           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5859           if (bitpos < HOST_BITS_PER_WIDE_INT)
5860             {
5861               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5862                 {
5863                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5864                   val[0] = -1;
5865                 }
5866             }
5867           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5868             {
5869               if (val[1] < 0)
5870                 val[0] = -1;
5871             }
5872           else if (val[0] & (((HOST_WIDE_INT) 1)
5873                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5874             val[0] |= ((HOST_WIDE_INT) -1)
5875                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5876         }
5877
5878       value = build_int_cst_wide (type, val[1], val[0]);
5879       add_pending_init (purpose, value);
5880     }
5881
5882   constructor_incremental = 0;
5883 }
5884
5885 /* Return value of FIELD in pending initializer or zero if the field was
5886    not initialized yet.  */
5887
5888 static tree
5889 find_init_member (tree field)
5890 {
5891   struct init_node *p;
5892
5893   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5894     {
5895       if (constructor_incremental
5896           && tree_int_cst_lt (field, constructor_unfilled_index))
5897         set_nonincremental_init ();
5898
5899       p = constructor_pending_elts;
5900       while (p)
5901         {
5902           if (tree_int_cst_lt (field, p->purpose))
5903             p = p->left;
5904           else if (tree_int_cst_lt (p->purpose, field))
5905             p = p->right;
5906           else
5907             return p->value;
5908         }
5909     }
5910   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5911     {
5912       tree bitpos = bit_position (field);
5913
5914       if (constructor_incremental
5915           && (!constructor_unfilled_fields
5916               || tree_int_cst_lt (bitpos,
5917                                   bit_position (constructor_unfilled_fields))))
5918         set_nonincremental_init ();
5919
5920       p = constructor_pending_elts;
5921       while (p)
5922         {
5923           if (field == p->purpose)
5924             return p->value;
5925           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5926             p = p->left;
5927           else
5928             p = p->right;
5929         }
5930     }
5931   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5932     {
5933       if (!VEC_empty (constructor_elt, constructor_elements)
5934           && (VEC_last (constructor_elt, constructor_elements)->index
5935               == field))
5936         return VEC_last (constructor_elt, constructor_elements)->value;
5937     }
5938   return 0;
5939 }
5940
5941 /* "Output" the next constructor element.
5942    At top level, really output it to assembler code now.
5943    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5944    TYPE is the data type that the containing data type wants here.
5945    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5946    If VALUE is a string constant, STRICT_STRING is true if it is
5947    unparenthesized or we should not warn here for it being parenthesized.
5948    For other types of VALUE, STRICT_STRING is not used.
5949
5950    PENDING if non-nil means output pending elements that belong
5951    right after this element.  (PENDING is normally 1;
5952    it is 0 while outputting pending elements, to avoid recursion.)  */
5953
5954 static void
5955 output_init_element (tree value, bool strict_string, tree type, tree field,
5956                      int pending)
5957 {
5958   constructor_elt *celt;
5959
5960   if (type == error_mark_node || value == error_mark_node)
5961     {
5962       constructor_erroneous = 1;
5963       return;
5964     }
5965   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5966       && (TREE_CODE (value) == STRING_CST
5967           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5968       && !(TREE_CODE (value) == STRING_CST
5969            && TREE_CODE (type) == ARRAY_TYPE
5970            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5971       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5972                      TYPE_MAIN_VARIANT (type)))
5973     value = array_to_pointer_conversion (value);
5974
5975   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
5976       && require_constant_value && !flag_isoc99 && pending)
5977     {
5978       /* As an extension, allow initializing objects with static storage
5979          duration with compound literals (which are then treated just as
5980          the brace enclosed list they contain).  */
5981       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
5982       value = DECL_INITIAL (decl);
5983     }
5984
5985   if (value == error_mark_node)
5986     constructor_erroneous = 1;
5987   else if (!TREE_CONSTANT (value))
5988     constructor_constant = 0;
5989   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
5990            || ((TREE_CODE (constructor_type) == RECORD_TYPE
5991                 || TREE_CODE (constructor_type) == UNION_TYPE)
5992                && DECL_C_BIT_FIELD (field)
5993                && TREE_CODE (value) != INTEGER_CST))
5994     constructor_simple = 0;
5995
5996   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
5997     {
5998       if (require_constant_value)
5999         {
6000           error_init ("initializer element is not constant");
6001           value = error_mark_node;
6002         }
6003       else if (require_constant_elements)
6004         pedwarn ("initializer element is not computable at load time");
6005     }
6006
6007   /* If this field is empty (and not at the end of structure),
6008      don't do anything other than checking the initializer.  */
6009   if (field
6010       && (TREE_TYPE (field) == error_mark_node
6011           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6012               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6013               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6014                   || TREE_CHAIN (field)))))
6015     return;
6016
6017   value = digest_init (type, value, strict_string, require_constant_value);
6018   if (value == error_mark_node)
6019     {
6020       constructor_erroneous = 1;
6021       return;
6022     }
6023
6024   /* If this element doesn't come next in sequence,
6025      put it on constructor_pending_elts.  */
6026   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6027       && (!constructor_incremental
6028           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6029     {
6030       if (constructor_incremental
6031           && tree_int_cst_lt (field, constructor_unfilled_index))
6032         set_nonincremental_init ();
6033
6034       add_pending_init (field, value);
6035       return;
6036     }
6037   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6038            && (!constructor_incremental
6039                || field != constructor_unfilled_fields))
6040     {
6041       /* We do this for records but not for unions.  In a union,
6042          no matter which field is specified, it can be initialized
6043          right away since it starts at the beginning of the union.  */
6044       if (constructor_incremental)
6045         {
6046           if (!constructor_unfilled_fields)
6047             set_nonincremental_init ();
6048           else
6049             {
6050               tree bitpos, unfillpos;
6051
6052               bitpos = bit_position (field);
6053               unfillpos = bit_position (constructor_unfilled_fields);
6054
6055               if (tree_int_cst_lt (bitpos, unfillpos))
6056                 set_nonincremental_init ();
6057             }
6058         }
6059
6060       add_pending_init (field, value);
6061       return;
6062     }
6063   else if (TREE_CODE (constructor_type) == UNION_TYPE
6064            && !VEC_empty (constructor_elt, constructor_elements))
6065     {
6066       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6067                                        constructor_elements)->value))
6068         warning_init ("initialized field with side-effects overwritten");
6069
6070       /* We can have just one union field set.  */
6071       constructor_elements = 0;
6072     }
6073
6074   /* Otherwise, output this element either to
6075      constructor_elements or to the assembler file.  */
6076
6077   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6078   celt->index = field;
6079   celt->value = value;
6080
6081   /* Advance the variable that indicates sequential elements output.  */
6082   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6083     constructor_unfilled_index
6084       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6085                     bitsize_one_node);
6086   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6087     {
6088       constructor_unfilled_fields
6089         = TREE_CHAIN (constructor_unfilled_fields);
6090
6091       /* Skip any nameless bit fields.  */
6092       while (constructor_unfilled_fields != 0
6093              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6094              && DECL_NAME (constructor_unfilled_fields) == 0)
6095         constructor_unfilled_fields =
6096           TREE_CHAIN (constructor_unfilled_fields);
6097     }
6098   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6099     constructor_unfilled_fields = 0;
6100
6101   /* Now output any pending elements which have become next.  */
6102   if (pending)
6103     output_pending_init_elements (0);
6104 }
6105
6106 /* Output any pending elements which have become next.
6107    As we output elements, constructor_unfilled_{fields,index}
6108    advances, which may cause other elements to become next;
6109    if so, they too are output.
6110
6111    If ALL is 0, we return when there are
6112    no more pending elements to output now.
6113
6114    If ALL is 1, we output space as necessary so that
6115    we can output all the pending elements.  */
6116
6117 static void
6118 output_pending_init_elements (int all)
6119 {
6120   struct init_node *elt = constructor_pending_elts;
6121   tree next;
6122
6123  retry:
6124
6125   /* Look through the whole pending tree.
6126      If we find an element that should be output now,
6127      output it.  Otherwise, set NEXT to the element
6128      that comes first among those still pending.  */
6129
6130   next = 0;
6131   while (elt)
6132     {
6133       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6134         {
6135           if (tree_int_cst_equal (elt->purpose,
6136                                   constructor_unfilled_index))
6137             output_init_element (elt->value, true,
6138                                  TREE_TYPE (constructor_type),
6139                                  constructor_unfilled_index, 0);
6140           else if (tree_int_cst_lt (constructor_unfilled_index,
6141                                     elt->purpose))
6142             {
6143               /* Advance to the next smaller node.  */
6144               if (elt->left)
6145                 elt = elt->left;
6146               else
6147                 {
6148                   /* We have reached the smallest node bigger than the
6149                      current unfilled index.  Fill the space first.  */
6150                   next = elt->purpose;
6151                   break;
6152                 }
6153             }
6154           else
6155             {
6156               /* Advance to the next bigger node.  */
6157               if (elt->right)
6158                 elt = elt->right;
6159               else
6160                 {
6161                   /* We have reached the biggest node in a subtree.  Find
6162                      the parent of it, which is the next bigger node.  */
6163                   while (elt->parent && elt->parent->right == elt)
6164                     elt = elt->parent;
6165                   elt = elt->parent;
6166                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6167                                               elt->purpose))
6168                     {
6169                       next = elt->purpose;
6170                       break;
6171                     }
6172                 }
6173             }
6174         }
6175       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6176                || TREE_CODE (constructor_type) == UNION_TYPE)
6177         {
6178           tree ctor_unfilled_bitpos, elt_bitpos;
6179
6180           /* If the current record is complete we are done.  */
6181           if (constructor_unfilled_fields == 0)
6182             break;
6183
6184           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6185           elt_bitpos = bit_position (elt->purpose);
6186           /* We can't compare fields here because there might be empty
6187              fields in between.  */
6188           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6189             {
6190               constructor_unfilled_fields = elt->purpose;
6191               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6192                                    elt->purpose, 0);
6193             }
6194           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6195             {
6196               /* Advance to the next smaller node.  */
6197               if (elt->left)
6198                 elt = elt->left;
6199               else
6200                 {
6201                   /* We have reached the smallest node bigger than the
6202                      current unfilled field.  Fill the space first.  */
6203                   next = elt->purpose;
6204                   break;
6205                 }
6206             }
6207           else
6208             {
6209               /* Advance to the next bigger node.  */
6210               if (elt->right)
6211                 elt = elt->right;
6212               else
6213                 {
6214                   /* We have reached the biggest node in a subtree.  Find
6215                      the parent of it, which is the next bigger node.  */
6216                   while (elt->parent && elt->parent->right == elt)
6217                     elt = elt->parent;
6218                   elt = elt->parent;
6219                   if (elt
6220                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6221                                            bit_position (elt->purpose))))
6222                     {
6223                       next = elt->purpose;
6224                       break;
6225                     }
6226                 }
6227             }
6228         }
6229     }
6230
6231   /* Ordinarily return, but not if we want to output all
6232      and there are elements left.  */
6233   if (!(all && next != 0))
6234     return;
6235
6236   /* If it's not incremental, just skip over the gap, so that after
6237      jumping to retry we will output the next successive element.  */
6238   if (TREE_CODE (constructor_type) == RECORD_TYPE
6239       || TREE_CODE (constructor_type) == UNION_TYPE)
6240     constructor_unfilled_fields = next;
6241   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6242     constructor_unfilled_index = next;
6243
6244   /* ELT now points to the node in the pending tree with the next
6245      initializer to output.  */
6246   goto retry;
6247 }
6248 \f
6249 /* Add one non-braced element to the current constructor level.
6250    This adjusts the current position within the constructor's type.
6251    This may also start or terminate implicit levels
6252    to handle a partly-braced initializer.
6253
6254    Once this has found the correct level for the new element,
6255    it calls output_init_element.  */
6256
6257 void
6258 process_init_element (struct c_expr value)
6259 {
6260   tree orig_value = value.value;
6261   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6262   bool strict_string = value.original_code == STRING_CST;
6263
6264   designator_depth = 0;
6265   designator_erroneous = 0;
6266
6267   /* Handle superfluous braces around string cst as in
6268      char x[] = {"foo"}; */
6269   if (string_flag
6270       && constructor_type
6271       && TREE_CODE (constructor_type) == ARRAY_TYPE
6272       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6273       && integer_zerop (constructor_unfilled_index))
6274     {
6275       if (constructor_stack->replacement_value.value)
6276         error_init ("excess elements in char array initializer");
6277       constructor_stack->replacement_value = value;
6278       return;
6279     }
6280
6281   if (constructor_stack->replacement_value.value != 0)
6282     {
6283       error_init ("excess elements in struct initializer");
6284       return;
6285     }
6286
6287   /* Ignore elements of a brace group if it is entirely superfluous
6288      and has already been diagnosed.  */
6289   if (constructor_type == 0)
6290     return;
6291
6292   /* If we've exhausted any levels that didn't have braces,
6293      pop them now.  */
6294   while (constructor_stack->implicit)
6295     {
6296       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6297            || TREE_CODE (constructor_type) == UNION_TYPE)
6298           && constructor_fields == 0)
6299         process_init_element (pop_init_level (1));
6300       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6301                && (constructor_max_index == 0
6302                    || tree_int_cst_lt (constructor_max_index,
6303                                        constructor_index)))
6304         process_init_element (pop_init_level (1));
6305       else
6306         break;
6307     }
6308
6309   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6310   if (constructor_range_stack)
6311     {
6312       /* If value is a compound literal and we'll be just using its
6313          content, don't put it into a SAVE_EXPR.  */
6314       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6315           || !require_constant_value
6316           || flag_isoc99)
6317         value.value = save_expr (value.value);
6318     }
6319
6320   while (1)
6321     {
6322       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6323         {
6324           tree fieldtype;
6325           enum tree_code fieldcode;
6326
6327           if (constructor_fields == 0)
6328             {
6329               pedwarn_init ("excess elements in struct initializer");
6330               break;
6331             }
6332
6333           fieldtype = TREE_TYPE (constructor_fields);
6334           if (fieldtype != error_mark_node)
6335             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6336           fieldcode = TREE_CODE (fieldtype);
6337
6338           /* Error for non-static initialization of a flexible array member.  */
6339           if (fieldcode == ARRAY_TYPE
6340               && !require_constant_value
6341               && TYPE_SIZE (fieldtype) == NULL_TREE
6342               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6343             {
6344               error_init ("non-static initialization of a flexible array member");
6345               break;
6346             }
6347
6348           /* Accept a string constant to initialize a subarray.  */
6349           if (value.value != 0
6350               && fieldcode == ARRAY_TYPE
6351               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6352               && string_flag)
6353             value.value = orig_value;
6354           /* Otherwise, if we have come to a subaggregate,
6355              and we don't have an element of its type, push into it.  */
6356           else if (value.value != 0
6357                    && value.value != error_mark_node
6358                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6359                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6360                        || fieldcode == UNION_TYPE))
6361             {
6362               push_init_level (1);
6363               continue;
6364             }
6365
6366           if (value.value)
6367             {
6368               push_member_name (constructor_fields);
6369               output_init_element (value.value, strict_string,
6370                                    fieldtype, constructor_fields, 1);
6371               RESTORE_SPELLING_DEPTH (constructor_depth);
6372             }
6373           else
6374             /* Do the bookkeeping for an element that was
6375                directly output as a constructor.  */
6376             {
6377               /* For a record, keep track of end position of last field.  */
6378               if (DECL_SIZE (constructor_fields))
6379                 constructor_bit_index
6380                   = size_binop (PLUS_EXPR,
6381                                 bit_position (constructor_fields),
6382                                 DECL_SIZE (constructor_fields));
6383
6384               /* If the current field was the first one not yet written out,
6385                  it isn't now, so update.  */
6386               if (constructor_unfilled_fields == constructor_fields)
6387                 {
6388                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6389                   /* Skip any nameless bit fields.  */
6390                   while (constructor_unfilled_fields != 0
6391                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6392                          && DECL_NAME (constructor_unfilled_fields) == 0)
6393                     constructor_unfilled_fields =
6394                       TREE_CHAIN (constructor_unfilled_fields);
6395                 }
6396             }
6397
6398           constructor_fields = TREE_CHAIN (constructor_fields);
6399           /* Skip any nameless bit fields at the beginning.  */
6400           while (constructor_fields != 0
6401                  && DECL_C_BIT_FIELD (constructor_fields)
6402                  && DECL_NAME (constructor_fields) == 0)
6403             constructor_fields = TREE_CHAIN (constructor_fields);
6404         }
6405       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6406         {
6407           tree fieldtype;
6408           enum tree_code fieldcode;
6409
6410           if (constructor_fields == 0)
6411             {
6412               pedwarn_init ("excess elements in union initializer");
6413               break;
6414             }
6415
6416           fieldtype = TREE_TYPE (constructor_fields);
6417           if (fieldtype != error_mark_node)
6418             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6419           fieldcode = TREE_CODE (fieldtype);
6420
6421           /* Warn that traditional C rejects initialization of unions.
6422              We skip the warning if the value is zero.  This is done
6423              under the assumption that the zero initializer in user
6424              code appears conditioned on e.g. __STDC__ to avoid
6425              "missing initializer" warnings and relies on default
6426              initialization to zero in the traditional C case.
6427              We also skip the warning if the initializer is designated,
6428              again on the assumption that this must be conditional on
6429              __STDC__ anyway (and we've already complained about the
6430              member-designator already).  */
6431           if (!in_system_header && !constructor_designated
6432               && !(value.value && (integer_zerop (value.value)
6433                                    || real_zerop (value.value))))
6434             warning (OPT_Wtraditional, "traditional C rejects initialization "
6435                      "of unions");
6436
6437           /* Accept a string constant to initialize a subarray.  */
6438           if (value.value != 0
6439               && fieldcode == ARRAY_TYPE
6440               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6441               && string_flag)
6442             value.value = orig_value;
6443           /* Otherwise, if we have come to a subaggregate,
6444              and we don't have an element of its type, push into it.  */
6445           else if (value.value != 0
6446                    && value.value != error_mark_node
6447                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6448                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6449                        || fieldcode == UNION_TYPE))
6450             {
6451               push_init_level (1);
6452               continue;
6453             }
6454
6455           if (value.value)
6456             {
6457               push_member_name (constructor_fields);
6458               output_init_element (value.value, strict_string,
6459                                    fieldtype, constructor_fields, 1);
6460               RESTORE_SPELLING_DEPTH (constructor_depth);
6461             }
6462           else
6463             /* Do the bookkeeping for an element that was
6464                directly output as a constructor.  */
6465             {
6466               constructor_bit_index = DECL_SIZE (constructor_fields);
6467               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6468             }
6469
6470           constructor_fields = 0;
6471         }
6472       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6473         {
6474           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6475           enum tree_code eltcode = TREE_CODE (elttype);
6476
6477           /* Accept a string constant to initialize a subarray.  */
6478           if (value.value != 0
6479               && eltcode == ARRAY_TYPE
6480               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6481               && string_flag)
6482             value.value = orig_value;
6483           /* Otherwise, if we have come to a subaggregate,
6484              and we don't have an element of its type, push into it.  */
6485           else if (value.value != 0
6486                    && value.value != error_mark_node
6487                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6488                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6489                        || eltcode == UNION_TYPE))
6490             {
6491               push_init_level (1);
6492               continue;
6493             }
6494
6495           if (constructor_max_index != 0
6496               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6497                   || integer_all_onesp (constructor_max_index)))
6498             {
6499               pedwarn_init ("excess elements in array initializer");
6500               break;
6501             }
6502
6503           /* Now output the actual element.  */
6504           if (value.value)
6505             {
6506               push_array_bounds (tree_low_cst (constructor_index, 0));
6507               output_init_element (value.value, strict_string,
6508                                    elttype, constructor_index, 1);
6509               RESTORE_SPELLING_DEPTH (constructor_depth);
6510             }
6511
6512           constructor_index
6513             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6514
6515           if (!value.value)
6516             /* If we are doing the bookkeeping for an element that was
6517                directly output as a constructor, we must update
6518                constructor_unfilled_index.  */
6519             constructor_unfilled_index = constructor_index;
6520         }
6521       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6522         {
6523           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6524
6525          /* Do a basic check of initializer size.  Note that vectors
6526             always have a fixed size derived from their type.  */
6527           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6528             {
6529               pedwarn_init ("excess elements in vector initializer");
6530               break;
6531             }
6532
6533           /* Now output the actual element.  */
6534           if (value.value)
6535             output_init_element (value.value, strict_string,
6536                                  elttype, constructor_index, 1);
6537
6538           constructor_index
6539             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6540
6541           if (!value.value)
6542             /* If we are doing the bookkeeping for an element that was
6543                directly output as a constructor, we must update
6544                constructor_unfilled_index.  */
6545             constructor_unfilled_index = constructor_index;
6546         }
6547
6548       /* Handle the sole element allowed in a braced initializer
6549          for a scalar variable.  */
6550       else if (constructor_type != error_mark_node
6551                && constructor_fields == 0)
6552         {
6553           pedwarn_init ("excess elements in scalar initializer");
6554           break;
6555         }
6556       else
6557         {
6558           if (value.value)
6559             output_init_element (value.value, strict_string,
6560                                  constructor_type, NULL_TREE, 1);
6561           constructor_fields = 0;
6562         }
6563
6564       /* Handle range initializers either at this level or anywhere higher
6565          in the designator stack.  */
6566       if (constructor_range_stack)
6567         {
6568           struct constructor_range_stack *p, *range_stack;
6569           int finish = 0;
6570
6571           range_stack = constructor_range_stack;
6572           constructor_range_stack = 0;
6573           while (constructor_stack != range_stack->stack)
6574             {
6575               gcc_assert (constructor_stack->implicit);
6576               process_init_element (pop_init_level (1));
6577             }
6578           for (p = range_stack;
6579                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6580                p = p->prev)
6581             {
6582               gcc_assert (constructor_stack->implicit);
6583               process_init_element (pop_init_level (1));
6584             }
6585
6586           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6587           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6588             finish = 1;
6589
6590           while (1)
6591             {
6592               constructor_index = p->index;
6593               constructor_fields = p->fields;
6594               if (finish && p->range_end && p->index == p->range_start)
6595                 {
6596                   finish = 0;
6597                   p->prev = 0;
6598                 }
6599               p = p->next;
6600               if (!p)
6601                 break;
6602               push_init_level (2);
6603               p->stack = constructor_stack;
6604               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6605                 p->index = p->range_start;
6606             }
6607
6608           if (!finish)
6609             constructor_range_stack = range_stack;
6610           continue;
6611         }
6612
6613       break;
6614     }
6615
6616   constructor_range_stack = 0;
6617 }
6618 \f
6619 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6620    (guaranteed to be 'volatile' or null) and ARGS (represented using
6621    an ASM_EXPR node).  */
6622 tree
6623 build_asm_stmt (tree cv_qualifier, tree args)
6624 {
6625   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6626     ASM_VOLATILE_P (args) = 1;
6627   return add_stmt (args);
6628 }
6629
6630 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6631    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6632    SIMPLE indicates whether there was anything at all after the
6633    string in the asm expression -- asm("blah") and asm("blah" : )
6634    are subtly different.  We use a ASM_EXPR node to represent this.  */
6635 tree
6636 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6637                 bool simple)
6638 {
6639   tree tail;
6640   tree args;
6641   int i;
6642   const char *constraint;
6643   const char **oconstraints;
6644   bool allows_mem, allows_reg, is_inout;
6645   int ninputs, noutputs;
6646
6647   ninputs = list_length (inputs);
6648   noutputs = list_length (outputs);
6649   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6650
6651   string = resolve_asm_operand_names (string, outputs, inputs);
6652
6653   /* Remove output conversions that change the type but not the mode.  */
6654   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6655     {
6656       tree output = TREE_VALUE (tail);
6657
6658       /* ??? Really, this should not be here.  Users should be using a
6659          proper lvalue, dammit.  But there's a long history of using casts
6660          in the output operands.  In cases like longlong.h, this becomes a
6661          primitive form of typechecking -- if the cast can be removed, then
6662          the output operand had a type of the proper width; otherwise we'll
6663          get an error.  Gross, but ...  */
6664       STRIP_NOPS (output);
6665
6666       if (!lvalue_or_else (output, lv_asm))
6667         output = error_mark_node;
6668
6669       if (output != error_mark_node
6670           && (TREE_READONLY (output)
6671               || TYPE_READONLY (TREE_TYPE (output))
6672               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6673                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6674                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6675         readonly_error (output, lv_asm);
6676
6677       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6678       oconstraints[i] = constraint;
6679
6680       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6681                                    &allows_mem, &allows_reg, &is_inout))
6682         {
6683           /* If the operand is going to end up in memory,
6684              mark it addressable.  */
6685           if (!allows_reg && !c_mark_addressable (output))
6686             output = error_mark_node;
6687         }
6688       else
6689         output = error_mark_node;
6690
6691       TREE_VALUE (tail) = output;
6692     }
6693
6694   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6695     {
6696       tree input;
6697
6698       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6699       input = TREE_VALUE (tail);
6700
6701       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6702                                   oconstraints, &allows_mem, &allows_reg))
6703         {
6704           /* If the operand is going to end up in memory,
6705              mark it addressable.  */
6706           if (!allows_reg && allows_mem)
6707             {
6708               /* Strip the nops as we allow this case.  FIXME, this really
6709                  should be rejected or made deprecated.  */
6710               STRIP_NOPS (input);
6711               if (!c_mark_addressable (input))
6712                 input = error_mark_node;
6713           }
6714         }
6715       else
6716         input = error_mark_node;
6717
6718       TREE_VALUE (tail) = input;
6719     }
6720
6721   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6722
6723   /* asm statements without outputs, including simple ones, are treated
6724      as volatile.  */
6725   ASM_INPUT_P (args) = simple;
6726   ASM_VOLATILE_P (args) = (noutputs == 0);
6727
6728   return args;
6729 }
6730 \f
6731 /* Generate a goto statement to LABEL.  */
6732
6733 tree
6734 c_finish_goto_label (tree label)
6735 {
6736   tree decl = lookup_label (label);
6737   if (!decl)
6738     return NULL_TREE;
6739
6740   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6741     {
6742       error ("jump into statement expression");
6743       return NULL_TREE;
6744     }
6745
6746   if (C_DECL_UNJUMPABLE_VM (decl))
6747     {
6748       error ("jump into scope of identifier with variably modified type");
6749       return NULL_TREE;
6750     }
6751
6752   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6753     {
6754       /* No jump from outside this statement expression context, so
6755          record that there is a jump from within this context.  */
6756       struct c_label_list *nlist;
6757       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6758       nlist->next = label_context_stack_se->labels_used;
6759       nlist->label = decl;
6760       label_context_stack_se->labels_used = nlist;
6761     }
6762
6763   if (!C_DECL_UNDEFINABLE_VM (decl))
6764     {
6765       /* No jump from outside this context context of identifiers with
6766          variably modified type, so record that there is a jump from
6767          within this context.  */
6768       struct c_label_list *nlist;
6769       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6770       nlist->next = label_context_stack_vm->labels_used;
6771       nlist->label = decl;
6772       label_context_stack_vm->labels_used = nlist;
6773     }
6774
6775   TREE_USED (decl) = 1;
6776   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6777 }
6778
6779 /* Generate a computed goto statement to EXPR.  */
6780
6781 tree
6782 c_finish_goto_ptr (tree expr)
6783 {
6784   if (pedantic)
6785     pedwarn ("ISO C forbids %<goto *expr;%>");
6786   expr = convert (ptr_type_node, expr);
6787   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6788 }
6789
6790 /* Generate a C `return' statement.  RETVAL is the expression for what
6791    to return, or a null pointer for `return;' with no value.  */
6792
6793 tree
6794 c_finish_return (tree retval)
6795 {
6796   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6797   bool no_warning = false;
6798
6799   if (TREE_THIS_VOLATILE (current_function_decl))
6800     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6801
6802   if (!retval)
6803     {
6804       current_function_returns_null = 1;
6805       if ((warn_return_type || flag_isoc99)
6806           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6807         {
6808           pedwarn_c99 ("%<return%> with no value, in "
6809                        "function returning non-void");
6810           no_warning = true;
6811         }
6812     }
6813   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6814     {
6815       current_function_returns_null = 1;
6816       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6817         pedwarn ("%<return%> with a value, in function returning void");
6818     }
6819   else
6820     {
6821       tree t = convert_for_assignment (valtype, retval, ic_return,
6822                                        NULL_TREE, NULL_TREE, 0);
6823       tree res = DECL_RESULT (current_function_decl);
6824       tree inner;
6825
6826       current_function_returns_value = 1;
6827       if (t == error_mark_node)
6828         return NULL_TREE;
6829
6830       inner = t = convert (TREE_TYPE (res), t);
6831
6832       /* Strip any conversions, additions, and subtractions, and see if
6833          we are returning the address of a local variable.  Warn if so.  */
6834       while (1)
6835         {
6836           switch (TREE_CODE (inner))
6837             {
6838             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6839             case PLUS_EXPR:
6840               inner = TREE_OPERAND (inner, 0);
6841               continue;
6842
6843             case MINUS_EXPR:
6844               /* If the second operand of the MINUS_EXPR has a pointer
6845                  type (or is converted from it), this may be valid, so
6846                  don't give a warning.  */
6847               {
6848                 tree op1 = TREE_OPERAND (inner, 1);
6849
6850                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6851                        && (TREE_CODE (op1) == NOP_EXPR
6852                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6853                            || TREE_CODE (op1) == CONVERT_EXPR))
6854                   op1 = TREE_OPERAND (op1, 0);
6855
6856                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6857                   break;
6858
6859                 inner = TREE_OPERAND (inner, 0);
6860                 continue;
6861               }
6862
6863             case ADDR_EXPR:
6864               inner = TREE_OPERAND (inner, 0);
6865
6866               while (REFERENCE_CLASS_P (inner)
6867                      && TREE_CODE (inner) != INDIRECT_REF)
6868                 inner = TREE_OPERAND (inner, 0);
6869
6870               if (DECL_P (inner)
6871                   && !DECL_EXTERNAL (inner)
6872                   && !TREE_STATIC (inner)
6873                   && DECL_CONTEXT (inner) == current_function_decl)
6874                 warning (0, "function returns address of local variable");
6875               break;
6876
6877             default:
6878               break;
6879             }
6880
6881           break;
6882         }
6883
6884       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6885     }
6886
6887   ret_stmt = build_stmt (RETURN_EXPR, retval);
6888   TREE_NO_WARNING (ret_stmt) |= no_warning;
6889   return add_stmt (ret_stmt);
6890 }
6891 \f
6892 struct c_switch {
6893   /* The SWITCH_EXPR being built.  */
6894   tree switch_expr;
6895
6896   /* The original type of the testing expression, i.e. before the
6897      default conversion is applied.  */
6898   tree orig_type;
6899
6900   /* A splay-tree mapping the low element of a case range to the high
6901      element, or NULL_TREE if there is no high element.  Used to
6902      determine whether or not a new case label duplicates an old case
6903      label.  We need a tree, rather than simply a hash table, because
6904      of the GNU case range extension.  */
6905   splay_tree cases;
6906
6907   /* Number of nested statement expressions within this switch
6908      statement; if nonzero, case and default labels may not
6909      appear.  */
6910   unsigned int blocked_stmt_expr;
6911
6912   /* Scope of outermost declarations of identifiers with variably
6913      modified type within this switch statement; if nonzero, case and
6914      default labels may not appear.  */
6915   unsigned int blocked_vm;
6916
6917   /* The next node on the stack.  */
6918   struct c_switch *next;
6919 };
6920
6921 /* A stack of the currently active switch statements.  The innermost
6922    switch statement is on the top of the stack.  There is no need to
6923    mark the stack for garbage collection because it is only active
6924    during the processing of the body of a function, and we never
6925    collect at that point.  */
6926
6927 struct c_switch *c_switch_stack;
6928
6929 /* Start a C switch statement, testing expression EXP.  Return the new
6930    SWITCH_EXPR.  */
6931
6932 tree
6933 c_start_case (tree exp)
6934 {
6935   enum tree_code code;
6936   tree type, orig_type = error_mark_node;
6937   struct c_switch *cs;
6938
6939   if (exp != error_mark_node)
6940     {
6941       code = TREE_CODE (TREE_TYPE (exp));
6942       orig_type = TREE_TYPE (exp);
6943
6944       if (!INTEGRAL_TYPE_P (orig_type)
6945           && code != ERROR_MARK)
6946         {
6947           error ("switch quantity not an integer");
6948           exp = integer_zero_node;
6949           orig_type = error_mark_node;
6950         }
6951       else
6952         {
6953           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6954
6955           if (!in_system_header
6956               && (type == long_integer_type_node
6957                   || type == long_unsigned_type_node))
6958             warning (OPT_Wtraditional, "%<long%> switch expression not "
6959                      "converted to %<int%> in ISO C");
6960
6961           exp = default_conversion (exp);
6962           type = TREE_TYPE (exp);
6963         }
6964     }
6965
6966   /* Add this new SWITCH_EXPR to the stack.  */
6967   cs = XNEW (struct c_switch);
6968   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6969   cs->orig_type = orig_type;
6970   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6971   cs->blocked_stmt_expr = 0;
6972   cs->blocked_vm = 0;
6973   cs->next = c_switch_stack;
6974   c_switch_stack = cs;
6975
6976   return add_stmt (cs->switch_expr);
6977 }
6978
6979 /* Process a case label.  */
6980
6981 tree
6982 do_case (tree low_value, tree high_value)
6983 {
6984   tree label = NULL_TREE;
6985
6986   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
6987       && !c_switch_stack->blocked_vm)
6988     {
6989       label = c_add_case_label (c_switch_stack->cases,
6990                                 SWITCH_COND (c_switch_stack->switch_expr),
6991                                 c_switch_stack->orig_type,
6992                                 low_value, high_value);
6993       if (label == error_mark_node)
6994         label = NULL_TREE;
6995     }
6996   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
6997     {
6998       if (low_value)
6999         error ("case label in statement expression not containing "
7000                "enclosing switch statement");
7001       else
7002         error ("%<default%> label in statement expression not containing "
7003                "enclosing switch statement");
7004     }
7005   else if (c_switch_stack && c_switch_stack->blocked_vm)
7006     {
7007       if (low_value)
7008         error ("case label in scope of identifier with variably modified "
7009                "type not containing enclosing switch statement");
7010       else
7011         error ("%<default%> label in scope of identifier with variably "
7012                "modified type not containing enclosing switch statement");
7013     }
7014   else if (low_value)
7015     error ("case label not within a switch statement");
7016   else
7017     error ("%<default%> label not within a switch statement");
7018
7019   return label;
7020 }
7021
7022 /* Finish the switch statement.  */
7023
7024 void
7025 c_finish_case (tree body)
7026 {
7027   struct c_switch *cs = c_switch_stack;
7028   location_t switch_location;
7029
7030   SWITCH_BODY (cs->switch_expr) = body;
7031
7032   /* We must not be within a statement expression nested in the switch
7033      at this point; we might, however, be within the scope of an
7034      identifier with variably modified type nested in the switch.  */
7035   gcc_assert (!cs->blocked_stmt_expr);
7036
7037   /* Emit warnings as needed.  */
7038   if (EXPR_HAS_LOCATION (cs->switch_expr))
7039     switch_location = EXPR_LOCATION (cs->switch_expr);
7040   else
7041     switch_location = input_location;
7042   c_do_switch_warnings (cs->cases, switch_location,
7043                         TREE_TYPE (cs->switch_expr),
7044                         SWITCH_COND (cs->switch_expr));
7045
7046   /* Pop the stack.  */
7047   c_switch_stack = cs->next;
7048   splay_tree_delete (cs->cases);
7049   XDELETE (cs);
7050 }
7051 \f
7052 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7053    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7054    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7055    statement, and was not surrounded with parenthesis.  */
7056
7057 void
7058 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7059                   tree else_block, bool nested_if)
7060 {
7061   tree stmt;
7062
7063   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7064   if (warn_parentheses && nested_if && else_block == NULL)
7065     {
7066       tree inner_if = then_block;
7067
7068       /* We know from the grammar productions that there is an IF nested
7069          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7070          it might not be exactly THEN_BLOCK, but should be the last
7071          non-container statement within.  */
7072       while (1)
7073         switch (TREE_CODE (inner_if))
7074           {
7075           case COND_EXPR:
7076             goto found;
7077           case BIND_EXPR:
7078             inner_if = BIND_EXPR_BODY (inner_if);
7079             break;
7080           case STATEMENT_LIST:
7081             inner_if = expr_last (then_block);
7082             break;
7083           case TRY_FINALLY_EXPR:
7084           case TRY_CATCH_EXPR:
7085             inner_if = TREE_OPERAND (inner_if, 0);
7086             break;
7087           default:
7088             gcc_unreachable ();
7089           }
7090     found:
7091
7092       if (COND_EXPR_ELSE (inner_if))
7093          warning (OPT_Wparentheses,
7094                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7095                   &if_locus);
7096     }
7097
7098   /* Diagnose ";" via the special empty statement node that we create.  */
7099   if (extra_warnings)
7100     {
7101       tree *inner_then = &then_block, *inner_else = &else_block;
7102
7103       if (TREE_CODE (*inner_then) == STATEMENT_LIST
7104           && STATEMENT_LIST_TAIL (*inner_then))
7105         inner_then = &STATEMENT_LIST_TAIL (*inner_then)->stmt;
7106       if (*inner_else && TREE_CODE (*inner_else) == STATEMENT_LIST
7107           && STATEMENT_LIST_TAIL (*inner_else))
7108         inner_else = &STATEMENT_LIST_TAIL (*inner_else)->stmt;
7109
7110       if (TREE_CODE (*inner_then) == NOP_EXPR && !TREE_TYPE (*inner_then))
7111         {
7112           if (!*inner_else)
7113             warning (0, "%Hempty body in an if-statement",
7114                      EXPR_LOCUS (*inner_then));
7115
7116           *inner_then = alloc_stmt_list ();
7117         }
7118       if (*inner_else
7119           && TREE_CODE (*inner_else) == NOP_EXPR
7120           && !TREE_TYPE (*inner_else))
7121         {
7122           warning (0, "%Hempty body in an else-statement",
7123                    EXPR_LOCUS (*inner_else));
7124
7125           *inner_else = alloc_stmt_list ();
7126         }
7127     }
7128
7129   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7130   SET_EXPR_LOCATION (stmt, if_locus);
7131   add_stmt (stmt);
7132 }
7133
7134 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7135    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7136    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7137    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7138    the continue label.  Everything is allowed to be NULL.  */
7139
7140 void
7141 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7142                tree blab, tree clab, bool cond_is_first)
7143 {
7144   tree entry = NULL, exit = NULL, t;
7145
7146   /* If the condition is zero don't generate a loop construct.  */
7147   if (cond && integer_zerop (cond))
7148     {
7149       if (cond_is_first)
7150         {
7151           t = build_and_jump (&blab);
7152           SET_EXPR_LOCATION (t, start_locus);
7153           add_stmt (t);
7154         }
7155     }
7156   else
7157     {
7158       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7159
7160       /* If we have an exit condition, then we build an IF with gotos either
7161          out of the loop, or to the top of it.  If there's no exit condition,
7162          then we just build a jump back to the top.  */
7163       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7164
7165       if (cond && !integer_nonzerop (cond))
7166         {
7167           /* Canonicalize the loop condition to the end.  This means
7168              generating a branch to the loop condition.  Reuse the
7169              continue label, if possible.  */
7170           if (cond_is_first)
7171             {
7172               if (incr || !clab)
7173                 {
7174                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7175                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7176                 }
7177               else
7178                 t = build1 (GOTO_EXPR, void_type_node, clab);
7179               SET_EXPR_LOCATION (t, start_locus);
7180               add_stmt (t);
7181             }
7182
7183           t = build_and_jump (&blab);
7184           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7185           if (cond_is_first)
7186             SET_EXPR_LOCATION (exit, start_locus);
7187           else
7188             SET_EXPR_LOCATION (exit, input_location);
7189         }
7190
7191       add_stmt (top);
7192     }
7193
7194   if (body)
7195     add_stmt (body);
7196   if (clab)
7197     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7198   if (incr)
7199     add_stmt (incr);
7200   if (entry)
7201     add_stmt (entry);
7202   if (exit)
7203     add_stmt (exit);
7204   if (blab)
7205     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7206 }
7207
7208 tree
7209 c_finish_bc_stmt (tree *label_p, bool is_break)
7210 {
7211   bool skip;
7212   tree label = *label_p;
7213
7214   /* In switch statements break is sometimes stylistically used after
7215      a return statement.  This can lead to spurious warnings about
7216      control reaching the end of a non-void function when it is
7217      inlined.  Note that we are calling block_may_fallthru with
7218      language specific tree nodes; this works because
7219      block_may_fallthru returns true when given something it does not
7220      understand.  */
7221   skip = !block_may_fallthru (cur_stmt_list);
7222
7223   if (!label)
7224     {
7225       if (!skip)
7226         *label_p = label = create_artificial_label ();
7227     }
7228   else if (TREE_CODE (label) != LABEL_DECL)
7229     {
7230       if (is_break)
7231         error ("break statement not within loop or switch");
7232       else
7233         error ("continue statement not within a loop");
7234       return NULL_TREE;
7235     }
7236
7237   if (skip)
7238     return NULL_TREE;
7239
7240   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7241 }
7242
7243 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7244
7245 static void
7246 emit_side_effect_warnings (tree expr)
7247 {
7248   if (expr == error_mark_node)
7249     ;
7250   else if (!TREE_SIDE_EFFECTS (expr))
7251     {
7252       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7253         warning (0, "%Hstatement with no effect",
7254                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7255     }
7256   else if (warn_unused_value)
7257     warn_if_unused_value (expr, input_location);
7258 }
7259
7260 /* Process an expression as if it were a complete statement.  Emit
7261    diagnostics, but do not call ADD_STMT.  */
7262
7263 tree
7264 c_process_expr_stmt (tree expr)
7265 {
7266   if (!expr)
7267     return NULL_TREE;
7268
7269   if (warn_sequence_point)
7270     verify_sequence_points (expr);
7271
7272   if (TREE_TYPE (expr) != error_mark_node
7273       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7274       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7275     error ("expression statement has incomplete type");
7276
7277   /* If we're not processing a statement expression, warn about unused values.
7278      Warnings for statement expressions will be emitted later, once we figure
7279      out which is the result.  */
7280   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7281       && (extra_warnings || warn_unused_value))
7282     emit_side_effect_warnings (expr);
7283
7284   /* If the expression is not of a type to which we cannot assign a line
7285      number, wrap the thing in a no-op NOP_EXPR.  */
7286   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7287     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7288
7289   if (EXPR_P (expr))
7290     SET_EXPR_LOCATION (expr, input_location);
7291
7292   return expr;
7293 }
7294
7295 /* Emit an expression as a statement.  */
7296
7297 tree
7298 c_finish_expr_stmt (tree expr)
7299 {
7300   if (expr)
7301     return add_stmt (c_process_expr_stmt (expr));
7302   else
7303     return NULL;
7304 }
7305
7306 /* Do the opposite and emit a statement as an expression.  To begin,
7307    create a new binding level and return it.  */
7308
7309 tree
7310 c_begin_stmt_expr (void)
7311 {
7312   tree ret;
7313   struct c_label_context_se *nstack;
7314   struct c_label_list *glist;
7315
7316   /* We must force a BLOCK for this level so that, if it is not expanded
7317      later, there is a way to turn off the entire subtree of blocks that
7318      are contained in it.  */
7319   keep_next_level ();
7320   ret = c_begin_compound_stmt (true);
7321   if (c_switch_stack)
7322     {
7323       c_switch_stack->blocked_stmt_expr++;
7324       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7325     }
7326   for (glist = label_context_stack_se->labels_used;
7327        glist != NULL;
7328        glist = glist->next)
7329     {
7330       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7331     }
7332   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7333   nstack->labels_def = NULL;
7334   nstack->labels_used = NULL;
7335   nstack->next = label_context_stack_se;
7336   label_context_stack_se = nstack;
7337
7338   /* Mark the current statement list as belonging to a statement list.  */
7339   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7340
7341   return ret;
7342 }
7343
7344 tree
7345 c_finish_stmt_expr (tree body)
7346 {
7347   tree last, type, tmp, val;
7348   tree *last_p;
7349   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7350
7351   body = c_end_compound_stmt (body, true);
7352   if (c_switch_stack)
7353     {
7354       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7355       c_switch_stack->blocked_stmt_expr--;
7356     }
7357   /* It is no longer possible to jump to labels defined within this
7358      statement expression.  */
7359   for (dlist = label_context_stack_se->labels_def;
7360        dlist != NULL;
7361        dlist = dlist->next)
7362     {
7363       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7364     }
7365   /* It is again possible to define labels with a goto just outside
7366      this statement expression.  */
7367   for (glist = label_context_stack_se->next->labels_used;
7368        glist != NULL;
7369        glist = glist->next)
7370     {
7371       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7372       glist_prev = glist;
7373     }
7374   if (glist_prev != NULL)
7375     glist_prev->next = label_context_stack_se->labels_used;
7376   else
7377     label_context_stack_se->next->labels_used
7378       = label_context_stack_se->labels_used;
7379   label_context_stack_se = label_context_stack_se->next;
7380
7381   /* Locate the last statement in BODY.  See c_end_compound_stmt
7382      about always returning a BIND_EXPR.  */
7383   last_p = &BIND_EXPR_BODY (body);
7384   last = BIND_EXPR_BODY (body);
7385
7386  continue_searching:
7387   if (TREE_CODE (last) == STATEMENT_LIST)
7388     {
7389       tree_stmt_iterator i;
7390
7391       /* This can happen with degenerate cases like ({ }).  No value.  */
7392       if (!TREE_SIDE_EFFECTS (last))
7393         return body;
7394
7395       /* If we're supposed to generate side effects warnings, process
7396          all of the statements except the last.  */
7397       if (extra_warnings || warn_unused_value)
7398         {
7399           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7400             emit_side_effect_warnings (tsi_stmt (i));
7401         }
7402       else
7403         i = tsi_last (last);
7404       last_p = tsi_stmt_ptr (i);
7405       last = *last_p;
7406     }
7407
7408   /* If the end of the list is exception related, then the list was split
7409      by a call to push_cleanup.  Continue searching.  */
7410   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7411       || TREE_CODE (last) == TRY_CATCH_EXPR)
7412     {
7413       last_p = &TREE_OPERAND (last, 0);
7414       last = *last_p;
7415       goto continue_searching;
7416     }
7417
7418   /* In the case that the BIND_EXPR is not necessary, return the
7419      expression out from inside it.  */
7420   if (last == error_mark_node
7421       || (last == BIND_EXPR_BODY (body)
7422           && BIND_EXPR_VARS (body) == NULL))
7423     {
7424       /* Do not warn if the return value of a statement expression is
7425          unused.  */
7426       if (EXPR_P (last))
7427         TREE_NO_WARNING (last) = 1;
7428       return last;
7429     }
7430
7431   /* Extract the type of said expression.  */
7432   type = TREE_TYPE (last);
7433
7434   /* If we're not returning a value at all, then the BIND_EXPR that
7435      we already have is a fine expression to return.  */
7436   if (!type || VOID_TYPE_P (type))
7437     return body;
7438
7439   /* Now that we've located the expression containing the value, it seems
7440      silly to make voidify_wrapper_expr repeat the process.  Create a
7441      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7442   tmp = create_tmp_var_raw (type, NULL);
7443
7444   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7445      tree_expr_nonnegative_p giving up immediately.  */
7446   val = last;
7447   if (TREE_CODE (val) == NOP_EXPR
7448       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7449     val = TREE_OPERAND (val, 0);
7450
7451   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7452   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7453
7454   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7455 }
7456
7457 /* Begin the scope of an identifier of variably modified type, scope
7458    number SCOPE.  Jumping from outside this scope to inside it is not
7459    permitted.  */
7460
7461 void
7462 c_begin_vm_scope (unsigned int scope)
7463 {
7464   struct c_label_context_vm *nstack;
7465   struct c_label_list *glist;
7466
7467   gcc_assert (scope > 0);
7468   if (c_switch_stack && !c_switch_stack->blocked_vm)
7469     c_switch_stack->blocked_vm = scope;
7470   for (glist = label_context_stack_vm->labels_used;
7471        glist != NULL;
7472        glist = glist->next)
7473     {
7474       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7475     }
7476   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7477   nstack->labels_def = NULL;
7478   nstack->labels_used = NULL;
7479   nstack->scope = scope;
7480   nstack->next = label_context_stack_vm;
7481   label_context_stack_vm = nstack;
7482 }
7483
7484 /* End a scope which may contain identifiers of variably modified
7485    type, scope number SCOPE.  */
7486
7487 void
7488 c_end_vm_scope (unsigned int scope)
7489 {
7490   if (label_context_stack_vm == NULL)
7491     return;
7492   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7493     c_switch_stack->blocked_vm = 0;
7494   /* We may have a number of nested scopes of identifiers with
7495      variably modified type, all at this depth.  Pop each in turn.  */
7496   while (label_context_stack_vm->scope == scope)
7497     {
7498       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7499
7500       /* It is no longer possible to jump to labels defined within this
7501          scope.  */
7502       for (dlist = label_context_stack_vm->labels_def;
7503            dlist != NULL;
7504            dlist = dlist->next)
7505         {
7506           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7507         }
7508       /* It is again possible to define labels with a goto just outside
7509          this scope.  */
7510       for (glist = label_context_stack_vm->next->labels_used;
7511            glist != NULL;
7512            glist = glist->next)
7513         {
7514           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7515           glist_prev = glist;
7516         }
7517       if (glist_prev != NULL)
7518         glist_prev->next = label_context_stack_vm->labels_used;
7519       else
7520         label_context_stack_vm->next->labels_used
7521           = label_context_stack_vm->labels_used;
7522       label_context_stack_vm = label_context_stack_vm->next;
7523     }
7524 }
7525 \f
7526 /* Begin and end compound statements.  This is as simple as pushing
7527    and popping new statement lists from the tree.  */
7528
7529 tree
7530 c_begin_compound_stmt (bool do_scope)
7531 {
7532   tree stmt = push_stmt_list ();
7533   if (do_scope)
7534     push_scope ();
7535   return stmt;
7536 }
7537
7538 tree
7539 c_end_compound_stmt (tree stmt, bool do_scope)
7540 {
7541   tree block = NULL;
7542
7543   if (do_scope)
7544     {
7545       if (c_dialect_objc ())
7546         objc_clear_super_receiver ();
7547       block = pop_scope ();
7548     }
7549
7550   stmt = pop_stmt_list (stmt);
7551   stmt = c_build_bind_expr (block, stmt);
7552
7553   /* If this compound statement is nested immediately inside a statement
7554      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7555      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7556      STATEMENT_LISTs merge, and thus we can lose track of what statement
7557      was really last.  */
7558   if (cur_stmt_list
7559       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7560       && TREE_CODE (stmt) != BIND_EXPR)
7561     {
7562       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7563       TREE_SIDE_EFFECTS (stmt) = 1;
7564     }
7565
7566   return stmt;
7567 }
7568
7569 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7570    when the current scope is exited.  EH_ONLY is true when this is not
7571    meant to apply to normal control flow transfer.  */
7572
7573 void
7574 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7575 {
7576   enum tree_code code;
7577   tree stmt, list;
7578   bool stmt_expr;
7579
7580   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7581   stmt = build_stmt (code, NULL, cleanup);
7582   add_stmt (stmt);
7583   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7584   list = push_stmt_list ();
7585   TREE_OPERAND (stmt, 0) = list;
7586   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7587 }
7588 \f
7589 /* Build a binary-operation expression without default conversions.
7590    CODE is the kind of expression to build.
7591    This function differs from `build' in several ways:
7592    the data type of the result is computed and recorded in it,
7593    warnings are generated if arg data types are invalid,
7594    special handling for addition and subtraction of pointers is known,
7595    and some optimization is done (operations on narrow ints
7596    are done in the narrower type when that gives the same result).
7597    Constant folding is also done before the result is returned.
7598
7599    Note that the operands will never have enumeral types, or function
7600    or array types, because either they will have the default conversions
7601    performed or they have both just been converted to some other type in which
7602    the arithmetic is to be done.  */
7603
7604 tree
7605 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7606                  int convert_p)
7607 {
7608   tree type0, type1;
7609   enum tree_code code0, code1;
7610   tree op0, op1;
7611   const char *invalid_op_diag;
7612
7613   /* Expression code to give to the expression when it is built.
7614      Normally this is CODE, which is what the caller asked for,
7615      but in some special cases we change it.  */
7616   enum tree_code resultcode = code;
7617
7618   /* Data type in which the computation is to be performed.
7619      In the simplest cases this is the common type of the arguments.  */
7620   tree result_type = NULL;
7621
7622   /* Nonzero means operands have already been type-converted
7623      in whatever way is necessary.
7624      Zero means they need to be converted to RESULT_TYPE.  */
7625   int converted = 0;
7626
7627   /* Nonzero means create the expression with this type, rather than
7628      RESULT_TYPE.  */
7629   tree build_type = 0;
7630
7631   /* Nonzero means after finally constructing the expression
7632      convert it to this type.  */
7633   tree final_type = 0;
7634
7635   /* Nonzero if this is an operation like MIN or MAX which can
7636      safely be computed in short if both args are promoted shorts.
7637      Also implies COMMON.
7638      -1 indicates a bitwise operation; this makes a difference
7639      in the exact conditions for when it is safe to do the operation
7640      in a narrower mode.  */
7641   int shorten = 0;
7642
7643   /* Nonzero if this is a comparison operation;
7644      if both args are promoted shorts, compare the original shorts.
7645      Also implies COMMON.  */
7646   int short_compare = 0;
7647
7648   /* Nonzero if this is a right-shift operation, which can be computed on the
7649      original short and then promoted if the operand is a promoted short.  */
7650   int short_shift = 0;
7651
7652   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7653   int common = 0;
7654
7655   /* True means types are compatible as far as ObjC is concerned.  */
7656   bool objc_ok;
7657
7658   if (convert_p)
7659     {
7660       op0 = default_conversion (orig_op0);
7661       op1 = default_conversion (orig_op1);
7662     }
7663   else
7664     {
7665       op0 = orig_op0;
7666       op1 = orig_op1;
7667     }
7668
7669   type0 = TREE_TYPE (op0);
7670   type1 = TREE_TYPE (op1);
7671
7672   /* The expression codes of the data types of the arguments tell us
7673      whether the arguments are integers, floating, pointers, etc.  */
7674   code0 = TREE_CODE (type0);
7675   code1 = TREE_CODE (type1);
7676
7677   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7678   STRIP_TYPE_NOPS (op0);
7679   STRIP_TYPE_NOPS (op1);
7680
7681   /* If an error was already reported for one of the arguments,
7682      avoid reporting another error.  */
7683
7684   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7685     return error_mark_node;
7686
7687   if ((invalid_op_diag
7688        = targetm.invalid_binary_op (code, type0, type1)))
7689     {
7690       error (invalid_op_diag);
7691       return error_mark_node;
7692     }
7693
7694   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7695
7696   switch (code)
7697     {
7698     case PLUS_EXPR:
7699       /* Handle the pointer + int case.  */
7700       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7701         return pointer_int_sum (PLUS_EXPR, op0, op1);
7702       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7703         return pointer_int_sum (PLUS_EXPR, op1, op0);
7704       else
7705         common = 1;
7706       break;
7707
7708     case MINUS_EXPR:
7709       /* Subtraction of two similar pointers.
7710          We must subtract them as integers, then divide by object size.  */
7711       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7712           && comp_target_types (type0, type1))
7713         return pointer_diff (op0, op1);
7714       /* Handle pointer minus int.  Just like pointer plus int.  */
7715       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7716         return pointer_int_sum (MINUS_EXPR, op0, op1);
7717       else
7718         common = 1;
7719       break;
7720
7721     case MULT_EXPR:
7722       common = 1;
7723       break;
7724
7725     case TRUNC_DIV_EXPR:
7726     case CEIL_DIV_EXPR:
7727     case FLOOR_DIV_EXPR:
7728     case ROUND_DIV_EXPR:
7729     case EXACT_DIV_EXPR:
7730       /* Floating point division by zero is a legitimate way to obtain
7731          infinities and NaNs.  */
7732       if (skip_evaluation == 0 && integer_zerop (op1))
7733         warning (OPT_Wdiv_by_zero, "division by zero");
7734
7735       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7736            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7737           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7738               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7739         {
7740           enum tree_code tcode0 = code0, tcode1 = code1;
7741
7742           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7743             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7744           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7745             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7746
7747           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7748             resultcode = RDIV_EXPR;
7749           else
7750             /* Although it would be tempting to shorten always here, that
7751                loses on some targets, since the modulo instruction is
7752                undefined if the quotient can't be represented in the
7753                computation mode.  We shorten only if unsigned or if
7754                dividing by something we know != -1.  */
7755             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7756                        || (TREE_CODE (op1) == INTEGER_CST
7757                            && !integer_all_onesp (op1)));
7758           common = 1;
7759         }
7760       break;
7761
7762     case BIT_AND_EXPR:
7763     case BIT_IOR_EXPR:
7764     case BIT_XOR_EXPR:
7765       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7766         shorten = -1;
7767       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7768         common = 1;
7769       break;
7770
7771     case TRUNC_MOD_EXPR:
7772     case FLOOR_MOD_EXPR:
7773       if (skip_evaluation == 0 && integer_zerop (op1))
7774         warning (OPT_Wdiv_by_zero, "division by zero");
7775
7776       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7777         {
7778           /* Although it would be tempting to shorten always here, that loses
7779              on some targets, since the modulo instruction is undefined if the
7780              quotient can't be represented in the computation mode.  We shorten
7781              only if unsigned or if dividing by something we know != -1.  */
7782           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7783                      || (TREE_CODE (op1) == INTEGER_CST
7784                          && !integer_all_onesp (op1)));
7785           common = 1;
7786         }
7787       break;
7788
7789     case TRUTH_ANDIF_EXPR:
7790     case TRUTH_ORIF_EXPR:
7791     case TRUTH_AND_EXPR:
7792     case TRUTH_OR_EXPR:
7793     case TRUTH_XOR_EXPR:
7794       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7795            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7796           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7797               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7798         {
7799           /* Result of these operations is always an int,
7800              but that does not mean the operands should be
7801              converted to ints!  */
7802           result_type = integer_type_node;
7803           op0 = c_common_truthvalue_conversion (op0);
7804           op1 = c_common_truthvalue_conversion (op1);
7805           converted = 1;
7806         }
7807       break;
7808
7809       /* Shift operations: result has same type as first operand;
7810          always convert second operand to int.
7811          Also set SHORT_SHIFT if shifting rightward.  */
7812
7813     case RSHIFT_EXPR:
7814       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7815         {
7816           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7817             {
7818               if (tree_int_cst_sgn (op1) < 0)
7819                 warning (0, "right shift count is negative");
7820               else
7821                 {
7822                   if (!integer_zerop (op1))
7823                     short_shift = 1;
7824
7825                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7826                     warning (0, "right shift count >= width of type");
7827                 }
7828             }
7829
7830           /* Use the type of the value to be shifted.  */
7831           result_type = type0;
7832           /* Convert the shift-count to an integer, regardless of size
7833              of value being shifted.  */
7834           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7835             op1 = convert (integer_type_node, op1);
7836           /* Avoid converting op1 to result_type later.  */
7837           converted = 1;
7838         }
7839       break;
7840
7841     case LSHIFT_EXPR:
7842       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7843         {
7844           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7845             {
7846               if (tree_int_cst_sgn (op1) < 0)
7847                 warning (0, "left shift count is negative");
7848
7849               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7850                 warning (0, "left shift count >= width of type");
7851             }
7852
7853           /* Use the type of the value to be shifted.  */
7854           result_type = type0;
7855           /* Convert the shift-count to an integer, regardless of size
7856              of value being shifted.  */
7857           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7858             op1 = convert (integer_type_node, op1);
7859           /* Avoid converting op1 to result_type later.  */
7860           converted = 1;
7861         }
7862       break;
7863
7864     case EQ_EXPR:
7865     case NE_EXPR:
7866       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7867         warning (OPT_Wfloat_equal,
7868                  "comparing floating point with == or != is unsafe");
7869       /* Result of comparison is always int,
7870          but don't convert the args to int!  */
7871       build_type = integer_type_node;
7872       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7873            || code0 == COMPLEX_TYPE)
7874           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7875               || code1 == COMPLEX_TYPE))
7876         short_compare = 1;
7877       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7878         {
7879           tree tt0 = TREE_TYPE (type0);
7880           tree tt1 = TREE_TYPE (type1);
7881           /* Anything compares with void *.  void * compares with anything.
7882              Otherwise, the targets must be compatible
7883              and both must be object or both incomplete.  */
7884           if (comp_target_types (type0, type1))
7885             result_type = common_pointer_type (type0, type1);
7886           else if (VOID_TYPE_P (tt0))
7887             {
7888               /* op0 != orig_op0 detects the case of something
7889                  whose value is 0 but which isn't a valid null ptr const.  */
7890               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7891                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7892                 pedwarn ("ISO C forbids comparison of %<void *%>"
7893                          " with function pointer");
7894             }
7895           else if (VOID_TYPE_P (tt1))
7896             {
7897               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7898                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7899                 pedwarn ("ISO C forbids comparison of %<void *%>"
7900                          " with function pointer");
7901             }
7902           else
7903             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7904             if (!objc_ok)
7905               pedwarn ("comparison of distinct pointer types lacks a cast");
7906
7907           if (result_type == NULL_TREE)
7908             result_type = ptr_type_node;
7909         }
7910       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7911                && integer_zerop (op1))
7912         result_type = type0;
7913       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7914                && integer_zerop (op0))
7915         result_type = type1;
7916       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7917         {
7918           result_type = type0;
7919           pedwarn ("comparison between pointer and integer");
7920         }
7921       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7922         {
7923           result_type = type1;
7924           pedwarn ("comparison between pointer and integer");
7925         }
7926       break;
7927
7928     case LE_EXPR:
7929     case GE_EXPR:
7930     case LT_EXPR:
7931     case GT_EXPR:
7932       build_type = integer_type_node;
7933       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7934           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7935         short_compare = 1;
7936       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7937         {
7938           if (comp_target_types (type0, type1))
7939             {
7940               result_type = common_pointer_type (type0, type1);
7941               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7942                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7943                 pedwarn ("comparison of complete and incomplete pointers");
7944               else if (pedantic
7945                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7946                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7947             }
7948           else
7949             {
7950               result_type = ptr_type_node;
7951               pedwarn ("comparison of distinct pointer types lacks a cast");
7952             }
7953         }
7954       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7955                && integer_zerop (op1))
7956         {
7957           result_type = type0;
7958           if (pedantic || extra_warnings)
7959             pedwarn ("ordered comparison of pointer with integer zero");
7960         }
7961       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7962                && integer_zerop (op0))
7963         {
7964           result_type = type1;
7965           if (pedantic)
7966             pedwarn ("ordered comparison of pointer with integer zero");
7967         }
7968       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7969         {
7970           result_type = type0;
7971           pedwarn ("comparison between pointer and integer");
7972         }
7973       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7974         {
7975           result_type = type1;
7976           pedwarn ("comparison between pointer and integer");
7977         }
7978       break;
7979
7980     default:
7981       gcc_unreachable ();
7982     }
7983
7984   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7985     return error_mark_node;
7986
7987   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
7988       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
7989           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
7990                                                     TREE_TYPE (type1))))
7991     {
7992       binary_op_error (code);
7993       return error_mark_node;
7994     }
7995
7996   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
7997        || code0 == VECTOR_TYPE)
7998       &&
7999       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8000        || code1 == VECTOR_TYPE))
8001     {
8002       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8003
8004       if (shorten || common || short_compare)
8005         result_type = c_common_type (type0, type1);
8006
8007       /* For certain operations (which identify themselves by shorten != 0)
8008          if both args were extended from the same smaller type,
8009          do the arithmetic in that type and then extend.
8010
8011          shorten !=0 and !=1 indicates a bitwise operation.
8012          For them, this optimization is safe only if
8013          both args are zero-extended or both are sign-extended.
8014          Otherwise, we might change the result.
8015          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8016          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8017
8018       if (shorten && none_complex)
8019         {
8020           int unsigned0, unsigned1;
8021           tree arg0 = get_narrower (op0, &unsigned0);
8022           tree arg1 = get_narrower (op1, &unsigned1);
8023           /* UNS is 1 if the operation to be done is an unsigned one.  */
8024           int uns = TYPE_UNSIGNED (result_type);
8025           tree type;
8026
8027           final_type = result_type;
8028
8029           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8030              but it *requires* conversion to FINAL_TYPE.  */
8031
8032           if ((TYPE_PRECISION (TREE_TYPE (op0))
8033                == TYPE_PRECISION (TREE_TYPE (arg0)))
8034               && TREE_TYPE (op0) != final_type)
8035             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8036           if ((TYPE_PRECISION (TREE_TYPE (op1))
8037                == TYPE_PRECISION (TREE_TYPE (arg1)))
8038               && TREE_TYPE (op1) != final_type)
8039             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8040
8041           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8042
8043           /* For bitwise operations, signedness of nominal type
8044              does not matter.  Consider only how operands were extended.  */
8045           if (shorten == -1)
8046             uns = unsigned0;
8047
8048           /* Note that in all three cases below we refrain from optimizing
8049              an unsigned operation on sign-extended args.
8050              That would not be valid.  */
8051
8052           /* Both args variable: if both extended in same way
8053              from same width, do it in that width.
8054              Do it unsigned if args were zero-extended.  */
8055           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8056                < TYPE_PRECISION (result_type))
8057               && (TYPE_PRECISION (TREE_TYPE (arg1))
8058                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8059               && unsigned0 == unsigned1
8060               && (unsigned0 || !uns))
8061             result_type
8062               = c_common_signed_or_unsigned_type
8063               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8064           else if (TREE_CODE (arg0) == INTEGER_CST
8065                    && (unsigned1 || !uns)
8066                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8067                        < TYPE_PRECISION (result_type))
8068                    && (type
8069                        = c_common_signed_or_unsigned_type (unsigned1,
8070                                                            TREE_TYPE (arg1)),
8071                        int_fits_type_p (arg0, type)))
8072             result_type = type;
8073           else if (TREE_CODE (arg1) == INTEGER_CST
8074                    && (unsigned0 || !uns)
8075                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8076                        < TYPE_PRECISION (result_type))
8077                    && (type
8078                        = c_common_signed_or_unsigned_type (unsigned0,
8079                                                            TREE_TYPE (arg0)),
8080                        int_fits_type_p (arg1, type)))
8081             result_type = type;
8082         }
8083
8084       /* Shifts can be shortened if shifting right.  */
8085
8086       if (short_shift)
8087         {
8088           int unsigned_arg;
8089           tree arg0 = get_narrower (op0, &unsigned_arg);
8090
8091           final_type = result_type;
8092
8093           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8094             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8095
8096           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8097               /* We can shorten only if the shift count is less than the
8098                  number of bits in the smaller type size.  */
8099               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8100               /* We cannot drop an unsigned shift after sign-extension.  */
8101               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8102             {
8103               /* Do an unsigned shift if the operand was zero-extended.  */
8104               result_type
8105                 = c_common_signed_or_unsigned_type (unsigned_arg,
8106                                                     TREE_TYPE (arg0));
8107               /* Convert value-to-be-shifted to that type.  */
8108               if (TREE_TYPE (op0) != result_type)
8109                 op0 = convert (result_type, op0);
8110               converted = 1;
8111             }
8112         }
8113
8114       /* Comparison operations are shortened too but differently.
8115          They identify themselves by setting short_compare = 1.  */
8116
8117       if (short_compare)
8118         {
8119           /* Don't write &op0, etc., because that would prevent op0
8120              from being kept in a register.
8121              Instead, make copies of the our local variables and
8122              pass the copies by reference, then copy them back afterward.  */
8123           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8124           enum tree_code xresultcode = resultcode;
8125           tree val
8126             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8127
8128           if (val != 0)
8129             return val;
8130
8131           op0 = xop0, op1 = xop1;
8132           converted = 1;
8133           resultcode = xresultcode;
8134
8135           if (warn_sign_compare && skip_evaluation == 0)
8136             {
8137               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8138               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8139               int unsignedp0, unsignedp1;
8140               tree primop0 = get_narrower (op0, &unsignedp0);
8141               tree primop1 = get_narrower (op1, &unsignedp1);
8142
8143               xop0 = orig_op0;
8144               xop1 = orig_op1;
8145               STRIP_TYPE_NOPS (xop0);
8146               STRIP_TYPE_NOPS (xop1);
8147
8148               /* Give warnings for comparisons between signed and unsigned
8149                  quantities that may fail.
8150
8151                  Do the checking based on the original operand trees, so that
8152                  casts will be considered, but default promotions won't be.
8153
8154                  Do not warn if the comparison is being done in a signed type,
8155                  since the signed type will only be chosen if it can represent
8156                  all the values of the unsigned type.  */
8157               if (!TYPE_UNSIGNED (result_type))
8158                 /* OK */;
8159               /* Do not warn if both operands are the same signedness.  */
8160               else if (op0_signed == op1_signed)
8161                 /* OK */;
8162               else
8163                 {
8164                   tree sop, uop;
8165
8166                   if (op0_signed)
8167                     sop = xop0, uop = xop1;
8168                   else
8169                     sop = xop1, uop = xop0;
8170
8171                   /* Do not warn if the signed quantity is an
8172                      unsuffixed integer literal (or some static
8173                      constant expression involving such literals or a
8174                      conditional expression involving such literals)
8175                      and it is non-negative.  */
8176                   if (tree_expr_nonnegative_p (sop))
8177                     /* OK */;
8178                   /* Do not warn if the comparison is an equality operation,
8179                      the unsigned quantity is an integral constant, and it
8180                      would fit in the result if the result were signed.  */
8181                   else if (TREE_CODE (uop) == INTEGER_CST
8182                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8183                            && int_fits_type_p
8184                            (uop, c_common_signed_type (result_type)))
8185                     /* OK */;
8186                   /* Do not warn if the unsigned quantity is an enumeration
8187                      constant and its maximum value would fit in the result
8188                      if the result were signed.  */
8189                   else if (TREE_CODE (uop) == INTEGER_CST
8190                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8191                            && int_fits_type_p
8192                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8193                             c_common_signed_type (result_type)))
8194                     /* OK */;
8195                   else
8196                     warning (0, "comparison between signed and unsigned");
8197                 }
8198
8199               /* Warn if two unsigned values are being compared in a size
8200                  larger than their original size, and one (and only one) is the
8201                  result of a `~' operator.  This comparison will always fail.
8202
8203                  Also warn if one operand is a constant, and the constant
8204                  does not have all bits set that are set in the ~ operand
8205                  when it is extended.  */
8206
8207               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8208                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8209                 {
8210                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8211                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8212                                             &unsignedp0);
8213                   else
8214                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8215                                             &unsignedp1);
8216
8217                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8218                     {
8219                       tree primop;
8220                       HOST_WIDE_INT constant, mask;
8221                       int unsignedp, bits;
8222
8223                       if (host_integerp (primop0, 0))
8224                         {
8225                           primop = primop1;
8226                           unsignedp = unsignedp1;
8227                           constant = tree_low_cst (primop0, 0);
8228                         }
8229                       else
8230                         {
8231                           primop = primop0;
8232                           unsignedp = unsignedp0;
8233                           constant = tree_low_cst (primop1, 0);
8234                         }
8235
8236                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8237                       if (bits < TYPE_PRECISION (result_type)
8238                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8239                         {
8240                           mask = (~(HOST_WIDE_INT) 0) << bits;
8241                           if ((mask & constant) != mask)
8242                             warning (0, "comparison of promoted ~unsigned with constant");
8243                         }
8244                     }
8245                   else if (unsignedp0 && unsignedp1
8246                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8247                                < TYPE_PRECISION (result_type))
8248                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8249                                < TYPE_PRECISION (result_type)))
8250                     warning (0, "comparison of promoted ~unsigned with unsigned");
8251                 }
8252             }
8253         }
8254     }
8255
8256   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8257      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8258      Then the expression will be built.
8259      It will be given type FINAL_TYPE if that is nonzero;
8260      otherwise, it will be given type RESULT_TYPE.  */
8261
8262   if (!result_type)
8263     {
8264       binary_op_error (code);
8265       return error_mark_node;
8266     }
8267
8268   if (!converted)
8269     {
8270       if (TREE_TYPE (op0) != result_type)
8271         op0 = convert (result_type, op0);
8272       if (TREE_TYPE (op1) != result_type)
8273         op1 = convert (result_type, op1);
8274
8275       /* This can happen if one operand has a vector type, and the other
8276          has a different type.  */
8277       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8278         return error_mark_node;
8279     }
8280
8281   if (build_type == NULL_TREE)
8282     build_type = result_type;
8283
8284   {
8285     /* Treat expressions in initializers specially as they can't trap.  */
8286     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8287                                                                     build_type,
8288                                                                     op0, op1)
8289                                          : fold_build2 (resultcode, build_type,
8290                                                         op0, op1);
8291
8292     if (final_type != 0)
8293       result = convert (final_type, result);
8294     return result;
8295   }
8296 }
8297
8298
8299 /* Convert EXPR to be a truth-value, validating its type for this
8300    purpose.  */
8301
8302 tree
8303 c_objc_common_truthvalue_conversion (tree expr)
8304 {
8305   switch (TREE_CODE (TREE_TYPE (expr)))
8306     {
8307     case ARRAY_TYPE:
8308       error ("used array that cannot be converted to pointer where scalar is required");
8309       return error_mark_node;
8310
8311     case RECORD_TYPE:
8312       error ("used struct type value where scalar is required");
8313       return error_mark_node;
8314
8315     case UNION_TYPE:
8316       error ("used union type value where scalar is required");
8317       return error_mark_node;
8318
8319     case FUNCTION_TYPE:
8320       gcc_unreachable ();
8321
8322     default:
8323       break;
8324     }
8325
8326   /* ??? Should we also give an error for void and vectors rather than
8327      leaving those to give errors later?  */
8328   return c_common_truthvalue_conversion (expr);
8329 }
8330 \f
8331
8332 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8333    required.  */
8334
8335 tree
8336 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8337                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8338 {
8339   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8340     {
8341       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8342       /* Executing a compound literal inside a function reinitializes
8343          it.  */
8344       if (!TREE_STATIC (decl))
8345         *se = true;
8346       return decl;
8347     }
8348   else
8349     return expr;
8350 }