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       if (flag_strict_aliasing && warn_strict_aliasing
3445           && TREE_CODE (type) == POINTER_TYPE
3446           && TREE_CODE (otype) == POINTER_TYPE
3447           && TREE_CODE (expr) == ADDR_EXPR
3448           && (DECL_P (TREE_OPERAND (expr, 0))
3449               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3450           && !VOID_TYPE_P (TREE_TYPE (type)))
3451         {
3452           /* Casting the address of an object to non void pointer. Warn
3453              if the cast breaks type based aliasing.  */
3454           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3455             warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
3456                      "might break strict-aliasing rules");
3457           else
3458             {
3459               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3460               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3461
3462               if (!alias_sets_conflict_p (set1, set2))
3463                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3464                          "pointer will break strict-aliasing rules");
3465               else if (warn_strict_aliasing > 1
3466                        && !alias_sets_might_conflict_p (set1, set2))
3467                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3468                          "pointer might break strict-aliasing rules");
3469             }
3470         }
3471
3472       /* If pedantic, warn for conversions between function and object
3473          pointer types, except for converting a null pointer constant
3474          to function pointer type.  */
3475       if (pedantic
3476           && TREE_CODE (type) == POINTER_TYPE
3477           && TREE_CODE (otype) == POINTER_TYPE
3478           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3479           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3480         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3481
3482       if (pedantic
3483           && TREE_CODE (type) == POINTER_TYPE
3484           && TREE_CODE (otype) == POINTER_TYPE
3485           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3486           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3487           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3488                && TREE_CODE (expr) != NOP_EXPR))
3489         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3490
3491       ovalue = value;
3492       value = convert (type, value);
3493
3494       /* Ignore any integer overflow caused by the cast.  */
3495       if (TREE_CODE (value) == INTEGER_CST)
3496         {
3497           if (CONSTANT_CLASS_P (ovalue)
3498               && (TREE_OVERFLOW (ovalue) || TREE_CONSTANT_OVERFLOW (ovalue)))
3499             {
3500               /* Avoid clobbering a shared constant.  */
3501               value = copy_node (value);
3502               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3503               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3504             }
3505           else if (TREE_OVERFLOW (value) || TREE_CONSTANT_OVERFLOW (value))
3506             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3507             value = build_int_cst_wide (TREE_TYPE (value),
3508                                         TREE_INT_CST_LOW (value),
3509                                         TREE_INT_CST_HIGH (value));
3510         }
3511     }
3512
3513   /* Don't let a cast be an lvalue.  */
3514   if (value == expr)
3515     value = non_lvalue (value);
3516
3517   return value;
3518 }
3519
3520 /* Interpret a cast of expression EXPR to type TYPE.  */
3521 tree
3522 c_cast_expr (struct c_type_name *type_name, tree expr)
3523 {
3524   tree type;
3525   int saved_wsp = warn_strict_prototypes;
3526
3527   /* This avoids warnings about unprototyped casts on
3528      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3529   if (TREE_CODE (expr) == INTEGER_CST)
3530     warn_strict_prototypes = 0;
3531   type = groktypename (type_name);
3532   warn_strict_prototypes = saved_wsp;
3533
3534   return build_c_cast (type, expr);
3535 }
3536
3537 \f
3538 /* Build an assignment expression of lvalue LHS from value RHS.
3539    MODIFYCODE is the code for a binary operator that we use
3540    to combine the old value of LHS with RHS to get the new value.
3541    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3542
3543 tree
3544 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3545 {
3546   tree result;
3547   tree newrhs;
3548   tree lhstype = TREE_TYPE (lhs);
3549   tree olhstype = lhstype;
3550
3551   /* Types that aren't fully specified cannot be used in assignments.  */
3552   lhs = require_complete_type (lhs);
3553
3554   /* Avoid duplicate error messages from operands that had errors.  */
3555   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3556     return error_mark_node;
3557
3558   STRIP_TYPE_NOPS (rhs);
3559
3560   newrhs = rhs;
3561
3562   /* If a binary op has been requested, combine the old LHS value with the RHS
3563      producing the value we should actually store into the LHS.  */
3564
3565   if (modifycode != NOP_EXPR)
3566     {
3567       lhs = stabilize_reference (lhs);
3568       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3569     }
3570
3571   if (!lvalue_or_else (lhs, lv_assign))
3572     return error_mark_node;
3573
3574   /* Give an error for storing in something that is 'const'.  */
3575
3576   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3577       || ((TREE_CODE (lhstype) == RECORD_TYPE
3578            || TREE_CODE (lhstype) == UNION_TYPE)
3579           && C_TYPE_FIELDS_READONLY (lhstype)))
3580     readonly_error (lhs, lv_assign);
3581
3582   /* If storing into a structure or union member,
3583      it has probably been given type `int'.
3584      Compute the type that would go with
3585      the actual amount of storage the member occupies.  */
3586
3587   if (TREE_CODE (lhs) == COMPONENT_REF
3588       && (TREE_CODE (lhstype) == INTEGER_TYPE
3589           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3590           || TREE_CODE (lhstype) == REAL_TYPE
3591           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3592     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3593
3594   /* If storing in a field that is in actuality a short or narrower than one,
3595      we must store in the field in its actual type.  */
3596
3597   if (lhstype != TREE_TYPE (lhs))
3598     {
3599       lhs = copy_node (lhs);
3600       TREE_TYPE (lhs) = lhstype;
3601     }
3602
3603   /* Convert new value to destination type.  */
3604
3605   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3606                                    NULL_TREE, NULL_TREE, 0);
3607   if (TREE_CODE (newrhs) == ERROR_MARK)
3608     return error_mark_node;
3609
3610   /* Emit ObjC write barrier, if necessary.  */
3611   if (c_dialect_objc () && flag_objc_gc)
3612     {
3613       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3614       if (result)
3615         return result;
3616     }
3617
3618   /* Scan operands.  */
3619
3620   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3621   TREE_SIDE_EFFECTS (result) = 1;
3622
3623   /* If we got the LHS in a different type for storing in,
3624      convert the result back to the nominal type of LHS
3625      so that the value we return always has the same type
3626      as the LHS argument.  */
3627
3628   if (olhstype == TREE_TYPE (result))
3629     return result;
3630   return convert_for_assignment (olhstype, result, ic_assign,
3631                                  NULL_TREE, NULL_TREE, 0);
3632 }
3633 \f
3634 /* Convert value RHS to type TYPE as preparation for an assignment
3635    to an lvalue of type TYPE.
3636    The real work of conversion is done by `convert'.
3637    The purpose of this function is to generate error messages
3638    for assignments that are not allowed in C.
3639    ERRTYPE says whether it is argument passing, assignment,
3640    initialization or return.
3641
3642    FUNCTION is a tree for the function being called.
3643    PARMNUM is the number of the argument, for printing in error messages.  */
3644
3645 static tree
3646 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3647                         tree fundecl, tree function, int parmnum)
3648 {
3649   enum tree_code codel = TREE_CODE (type);
3650   tree rhstype;
3651   enum tree_code coder;
3652   tree rname = NULL_TREE;
3653   bool objc_ok = false;
3654
3655   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3656     {
3657       tree selector;
3658       /* Change pointer to function to the function itself for
3659          diagnostics.  */
3660       if (TREE_CODE (function) == ADDR_EXPR
3661           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3662         function = TREE_OPERAND (function, 0);
3663
3664       /* Handle an ObjC selector specially for diagnostics.  */
3665       selector = objc_message_selector ();
3666       rname = function;
3667       if (selector && parmnum > 2)
3668         {
3669           rname = selector;
3670           parmnum -= 2;
3671         }
3672     }
3673
3674   /* This macro is used to emit diagnostics to ensure that all format
3675      strings are complete sentences, visible to gettext and checked at
3676      compile time.  */
3677 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3678   do {                                          \
3679     switch (errtype)                            \
3680       {                                         \
3681       case ic_argpass:                          \
3682         pedwarn (AR, parmnum, rname);           \
3683         break;                                  \
3684       case ic_argpass_nonproto:                 \
3685         warning (0, AR, parmnum, rname);                \
3686         break;                                  \
3687       case ic_assign:                           \
3688         pedwarn (AS);                           \
3689         break;                                  \
3690       case ic_init:                             \
3691         pedwarn (IN);                           \
3692         break;                                  \
3693       case ic_return:                           \
3694         pedwarn (RE);                           \
3695         break;                                  \
3696       default:                                  \
3697         gcc_unreachable ();                     \
3698       }                                         \
3699   } while (0)
3700
3701   STRIP_TYPE_NOPS (rhs);
3702
3703   if (optimize && TREE_CODE (rhs) == VAR_DECL
3704            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3705     rhs = decl_constant_value_for_broken_optimization (rhs);
3706
3707   rhstype = TREE_TYPE (rhs);
3708   coder = TREE_CODE (rhstype);
3709
3710   if (coder == ERROR_MARK)
3711     return error_mark_node;
3712
3713   if (c_dialect_objc ())
3714     {
3715       int parmno;
3716
3717       switch (errtype)
3718         {
3719         case ic_return:
3720           parmno = 0;
3721           break;
3722
3723         case ic_assign:
3724           parmno = -1;
3725           break;
3726
3727         case ic_init:
3728           parmno = -2;
3729           break;
3730
3731         default:
3732           parmno = parmnum;
3733           break;
3734         }
3735
3736       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3737     }
3738
3739   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3740     {
3741       overflow_warning (rhs);
3742       return rhs;
3743     }
3744
3745   if (coder == VOID_TYPE)
3746     {
3747       /* Except for passing an argument to an unprototyped function,
3748          this is a constraint violation.  When passing an argument to
3749          an unprototyped function, it is compile-time undefined;
3750          making it a constraint in that case was rejected in
3751          DR#252.  */
3752       error ("void value not ignored as it ought to be");
3753       return error_mark_node;
3754     }
3755   /* A type converts to a reference to it.
3756      This code doesn't fully support references, it's just for the
3757      special case of va_start and va_copy.  */
3758   if (codel == REFERENCE_TYPE
3759       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3760     {
3761       if (!lvalue_p (rhs))
3762         {
3763           error ("cannot pass rvalue to reference parameter");
3764           return error_mark_node;
3765         }
3766       if (!c_mark_addressable (rhs))
3767         return error_mark_node;
3768       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3769
3770       /* We already know that these two types are compatible, but they
3771          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3772          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3773          likely to be va_list, a typedef to __builtin_va_list, which
3774          is different enough that it will cause problems later.  */
3775       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3776         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3777
3778       rhs = build1 (NOP_EXPR, type, rhs);
3779       return rhs;
3780     }
3781   /* Some types can interconvert without explicit casts.  */
3782   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3783            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3784     return convert (type, rhs);
3785   /* Arithmetic types all interconvert, and enum is treated like int.  */
3786   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3787             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3788             || codel == BOOLEAN_TYPE)
3789            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3790                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3791                || coder == BOOLEAN_TYPE))
3792     return convert_and_check (type, rhs);
3793
3794   /* Conversion to a transparent union from its member types.
3795      This applies only to function arguments.  */
3796   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3797            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3798     {
3799       tree memb, marginal_memb = NULL_TREE;
3800
3801       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3802         {
3803           tree memb_type = TREE_TYPE (memb);
3804
3805           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3806                          TYPE_MAIN_VARIANT (rhstype)))
3807             break;
3808
3809           if (TREE_CODE (memb_type) != POINTER_TYPE)
3810             continue;
3811
3812           if (coder == POINTER_TYPE)
3813             {
3814               tree ttl = TREE_TYPE (memb_type);
3815               tree ttr = TREE_TYPE (rhstype);
3816
3817               /* Any non-function converts to a [const][volatile] void *
3818                  and vice versa; otherwise, targets must be the same.
3819                  Meanwhile, the lhs target must have all the qualifiers of
3820                  the rhs.  */
3821               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3822                   || comp_target_types (memb_type, rhstype))
3823                 {
3824                   /* If this type won't generate any warnings, use it.  */
3825                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3826                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3827                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3828                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3829                              == TYPE_QUALS (ttr))
3830                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3831                              == TYPE_QUALS (ttl))))
3832                     break;
3833
3834                   /* Keep looking for a better type, but remember this one.  */
3835                   if (!marginal_memb)
3836                     marginal_memb = memb;
3837                 }
3838             }
3839
3840           /* Can convert integer zero to any pointer type.  */
3841           if (integer_zerop (rhs)
3842               || (TREE_CODE (rhs) == NOP_EXPR
3843                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3844             {
3845               rhs = null_pointer_node;
3846               break;
3847             }
3848         }
3849
3850       if (memb || marginal_memb)
3851         {
3852           if (!memb)
3853             {
3854               /* We have only a marginally acceptable member type;
3855                  it needs a warning.  */
3856               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3857               tree ttr = TREE_TYPE (rhstype);
3858
3859               /* Const and volatile mean something different for function
3860                  types, so the usual warnings are not appropriate.  */
3861               if (TREE_CODE (ttr) == FUNCTION_TYPE
3862                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3863                 {
3864                   /* Because const and volatile on functions are
3865                      restrictions that say the function will not do
3866                      certain things, it is okay to use a const or volatile
3867                      function where an ordinary one is wanted, but not
3868                      vice-versa.  */
3869                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3870                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3871                                             "makes qualified function "
3872                                             "pointer from unqualified"),
3873                                          G_("assignment makes qualified "
3874                                             "function pointer from "
3875                                             "unqualified"),
3876                                          G_("initialization makes qualified "
3877                                             "function pointer from "
3878                                             "unqualified"),
3879                                          G_("return makes qualified function "
3880                                             "pointer from unqualified"));
3881                 }
3882               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3883                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3884                                         "qualifiers from pointer target type"),
3885                                      G_("assignment discards qualifiers "
3886                                         "from pointer target type"),
3887                                      G_("initialization discards qualifiers "
3888                                         "from pointer target type"),
3889                                      G_("return discards qualifiers from "
3890                                         "pointer target type"));
3891
3892               memb = marginal_memb;
3893             }
3894
3895           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3896             pedwarn ("ISO C prohibits argument conversion to union type");
3897
3898           return build_constructor_single (type, memb, rhs);
3899         }
3900     }
3901
3902   /* Conversions among pointers */
3903   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3904            && (coder == codel))
3905     {
3906       tree ttl = TREE_TYPE (type);
3907       tree ttr = TREE_TYPE (rhstype);
3908       tree mvl = ttl;
3909       tree mvr = ttr;
3910       bool is_opaque_pointer;
3911       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3912
3913       if (TREE_CODE (mvl) != ARRAY_TYPE)
3914         mvl = TYPE_MAIN_VARIANT (mvl);
3915       if (TREE_CODE (mvr) != ARRAY_TYPE)
3916         mvr = TYPE_MAIN_VARIANT (mvr);
3917       /* Opaque pointers are treated like void pointers.  */
3918       is_opaque_pointer = (targetm.vector_opaque_p (type)
3919                            || targetm.vector_opaque_p (rhstype))
3920         && TREE_CODE (ttl) == VECTOR_TYPE
3921         && TREE_CODE (ttr) == VECTOR_TYPE;
3922
3923       /* C++ does not allow the implicit conversion void* -> T*.  However,
3924          for the purpose of reducing the number of false positives, we
3925          tolerate the special case of
3926
3927                 int *p = NULL;
3928
3929          where NULL is typically defined in C to be '(void *) 0'.  */
3930       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3931         warning (OPT_Wc___compat, "request for implicit conversion from "
3932                  "%qT to %qT not permitted in C++", rhstype, type);
3933
3934       /* Check if the right-hand side has a format attribute but the
3935          left-hand side doesn't.  */
3936       if (warn_missing_format_attribute
3937           && check_missing_format_attribute (type, rhstype))
3938         {
3939           switch (errtype)
3940           {
3941           case ic_argpass:
3942           case ic_argpass_nonproto:
3943             warning (OPT_Wmissing_format_attribute,
3944                      "argument %d of %qE might be "
3945                      "a candidate for a format attribute",
3946                      parmnum, rname);
3947             break;
3948           case ic_assign:
3949             warning (OPT_Wmissing_format_attribute,
3950                      "assignment left-hand side might be "
3951                      "a candidate for a format attribute");
3952             break;
3953           case ic_init:
3954             warning (OPT_Wmissing_format_attribute,
3955                      "initialization left-hand side might be "
3956                      "a candidate for a format attribute");
3957             break;
3958           case ic_return:
3959             warning (OPT_Wmissing_format_attribute,
3960                      "return type might be "
3961                      "a candidate for a format attribute");
3962             break;
3963           default:
3964             gcc_unreachable ();
3965           }
3966         }
3967
3968       /* Any non-function converts to a [const][volatile] void *
3969          and vice versa; otherwise, targets must be the same.
3970          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3971       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3972           || (target_cmp = comp_target_types (type, rhstype))
3973           || is_opaque_pointer
3974           || (c_common_unsigned_type (mvl)
3975               == c_common_unsigned_type (mvr)))
3976         {
3977           if (pedantic
3978               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3979                   ||
3980                   (VOID_TYPE_P (ttr)
3981                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3982                       which are not ANSI null ptr constants.  */
3983                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3984                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3985             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3986                                     "%qE between function pointer "
3987                                     "and %<void *%>"),
3988                                  G_("ISO C forbids assignment between "
3989                                     "function pointer and %<void *%>"),
3990                                  G_("ISO C forbids initialization between "
3991                                     "function pointer and %<void *%>"),
3992                                  G_("ISO C forbids return between function "
3993                                     "pointer and %<void *%>"));
3994           /* Const and volatile mean something different for function types,
3995              so the usual warnings are not appropriate.  */
3996           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3997                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3998             {
3999               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4000                 {
4001                   /* Types differing only by the presence of the 'volatile'
4002                      qualifier are acceptable if the 'volatile' has been added
4003                      in by the Objective-C EH machinery.  */
4004                   if (!objc_type_quals_match (ttl, ttr))
4005                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4006                                             "qualifiers from pointer target type"),
4007                                          G_("assignment discards qualifiers "
4008                                             "from pointer target type"),
4009                                          G_("initialization discards qualifiers "
4010                                             "from pointer target type"),
4011                                          G_("return discards qualifiers from "
4012                                             "pointer target type"));
4013                 }
4014               /* If this is not a case of ignoring a mismatch in signedness,
4015                  no warning.  */
4016               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4017                        || target_cmp)
4018                 ;
4019               /* If there is a mismatch, do warn.  */
4020               else if (warn_pointer_sign)
4021                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4022                                         "%d of %qE differ in signedness"),
4023                                      G_("pointer targets in assignment "
4024                                         "differ in signedness"),
4025                                      G_("pointer targets in initialization "
4026                                         "differ in signedness"),
4027                                      G_("pointer targets in return differ "
4028                                         "in signedness"));
4029             }
4030           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4031                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4032             {
4033               /* Because const and volatile on functions are restrictions
4034                  that say the function will not do certain things,
4035                  it is okay to use a const or volatile function
4036                  where an ordinary one is wanted, but not vice-versa.  */
4037               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4038                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4039                                         "qualified function pointer "
4040                                         "from unqualified"),
4041                                      G_("assignment makes qualified function "
4042                                         "pointer from unqualified"),
4043                                      G_("initialization makes qualified "
4044                                         "function pointer from unqualified"),
4045                                      G_("return makes qualified function "
4046                                         "pointer from unqualified"));
4047             }
4048         }
4049       else
4050         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4051         if (!objc_ok)
4052           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4053                                   "incompatible pointer type"),
4054                                G_("assignment from incompatible pointer type"),
4055                                G_("initialization from incompatible "
4056                                   "pointer type"),
4057                                G_("return from incompatible pointer type"));
4058
4059       return convert (type, rhs);
4060     }
4061   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4062     {
4063       /* ??? This should not be an error when inlining calls to
4064          unprototyped functions.  */
4065       error ("invalid use of non-lvalue array");
4066       return error_mark_node;
4067     }
4068   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4069     {
4070       /* An explicit constant 0 can convert to a pointer,
4071          or one that results from arithmetic, even including
4072          a cast to integer type.  */
4073       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
4074           &&
4075           !(TREE_CODE (rhs) == NOP_EXPR
4076             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
4077             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
4078             && integer_zerop (TREE_OPERAND (rhs, 0))))
4079         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4080                                 "pointer from integer without a cast"),
4081                              G_("assignment makes pointer from integer "
4082                                 "without a cast"),
4083                              G_("initialization makes pointer from "
4084                                 "integer without a cast"),
4085                              G_("return makes pointer from integer "
4086                                 "without a cast"));
4087
4088       return convert (type, rhs);
4089     }
4090   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4091     {
4092       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4093                               "from pointer without a cast"),
4094                            G_("assignment makes integer from pointer "
4095                               "without a cast"),
4096                            G_("initialization makes integer from pointer "
4097                               "without a cast"),
4098                            G_("return makes integer from pointer "
4099                               "without a cast"));
4100       return convert (type, rhs);
4101     }
4102   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4103     return convert (type, rhs);
4104
4105   switch (errtype)
4106     {
4107     case ic_argpass:
4108     case ic_argpass_nonproto:
4109       /* ??? This should not be an error when inlining calls to
4110          unprototyped functions.  */
4111       error ("incompatible type for argument %d of %qE", parmnum, rname);
4112       break;
4113     case ic_assign:
4114       error ("incompatible types in assignment");
4115       break;
4116     case ic_init:
4117       error ("incompatible types in initialization");
4118       break;
4119     case ic_return:
4120       error ("incompatible types in return");
4121       break;
4122     default:
4123       gcc_unreachable ();
4124     }
4125
4126   return error_mark_node;
4127 }
4128
4129 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4130    is used for error and waring reporting and indicates which argument
4131    is being processed.  */
4132
4133 tree
4134 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4135 {
4136   tree ret, type;
4137
4138   /* If FN was prototyped, the value has been converted already
4139      in convert_arguments.  */
4140   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4141     return value;
4142
4143   type = TREE_TYPE (parm);
4144   ret = convert_for_assignment (type, value,
4145                                 ic_argpass_nonproto, fn,
4146                                 fn, argnum);
4147   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4148       && INTEGRAL_TYPE_P (type)
4149       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4150     ret = default_conversion (ret);
4151   return ret;
4152 }
4153 \f
4154 /* If VALUE is a compound expr all of whose expressions are constant, then
4155    return its value.  Otherwise, return error_mark_node.
4156
4157    This is for handling COMPOUND_EXPRs as initializer elements
4158    which is allowed with a warning when -pedantic is specified.  */
4159
4160 static tree
4161 valid_compound_expr_initializer (tree value, tree endtype)
4162 {
4163   if (TREE_CODE (value) == COMPOUND_EXPR)
4164     {
4165       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4166           == error_mark_node)
4167         return error_mark_node;
4168       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4169                                               endtype);
4170     }
4171   else if (!initializer_constant_valid_p (value, endtype))
4172     return error_mark_node;
4173   else
4174     return value;
4175 }
4176 \f
4177 /* Perform appropriate conversions on the initial value of a variable,
4178    store it in the declaration DECL,
4179    and print any error messages that are appropriate.
4180    If the init is invalid, store an ERROR_MARK.  */
4181
4182 void
4183 store_init_value (tree decl, tree init)
4184 {
4185   tree value, type;
4186
4187   /* If variable's type was invalidly declared, just ignore it.  */
4188
4189   type = TREE_TYPE (decl);
4190   if (TREE_CODE (type) == ERROR_MARK)
4191     return;
4192
4193   /* Digest the specified initializer into an expression.  */
4194
4195   value = digest_init (type, init, true, TREE_STATIC (decl));
4196
4197   /* Store the expression if valid; else report error.  */
4198
4199   if (!in_system_header
4200       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4201     warning (OPT_Wtraditional, "traditional C rejects automatic "
4202              "aggregate initialization");
4203
4204   DECL_INITIAL (decl) = value;
4205
4206   /* ANSI wants warnings about out-of-range constant initializers.  */
4207   STRIP_TYPE_NOPS (value);
4208   constant_expression_warning (value);
4209
4210   /* Check if we need to set array size from compound literal size.  */
4211   if (TREE_CODE (type) == ARRAY_TYPE
4212       && TYPE_DOMAIN (type) == 0
4213       && value != error_mark_node)
4214     {
4215       tree inside_init = init;
4216
4217       STRIP_TYPE_NOPS (inside_init);
4218       inside_init = fold (inside_init);
4219
4220       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4221         {
4222           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4223
4224           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4225             {
4226               /* For int foo[] = (int [3]){1}; we need to set array size
4227                  now since later on array initializer will be just the
4228                  brace enclosed list of the compound literal.  */
4229               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4230               layout_type (type);
4231               layout_decl (decl, 0);
4232             }
4233         }
4234     }
4235 }
4236 \f
4237 /* Methods for storing and printing names for error messages.  */
4238
4239 /* Implement a spelling stack that allows components of a name to be pushed
4240    and popped.  Each element on the stack is this structure.  */
4241
4242 struct spelling
4243 {
4244   int kind;
4245   union
4246     {
4247       int i;
4248       const char *s;
4249     } u;
4250 };
4251
4252 #define SPELLING_STRING 1
4253 #define SPELLING_MEMBER 2
4254 #define SPELLING_BOUNDS 3
4255
4256 static struct spelling *spelling;       /* Next stack element (unused).  */
4257 static struct spelling *spelling_base;  /* Spelling stack base.  */
4258 static int spelling_size;               /* Size of the spelling stack.  */
4259
4260 /* Macros to save and restore the spelling stack around push_... functions.
4261    Alternative to SAVE_SPELLING_STACK.  */
4262
4263 #define SPELLING_DEPTH() (spelling - spelling_base)
4264 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4265
4266 /* Push an element on the spelling stack with type KIND and assign VALUE
4267    to MEMBER.  */
4268
4269 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4270 {                                                                       \
4271   int depth = SPELLING_DEPTH ();                                        \
4272                                                                         \
4273   if (depth >= spelling_size)                                           \
4274     {                                                                   \
4275       spelling_size += 10;                                              \
4276       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4277                                   spelling_size);                       \
4278       RESTORE_SPELLING_DEPTH (depth);                                   \
4279     }                                                                   \
4280                                                                         \
4281   spelling->kind = (KIND);                                              \
4282   spelling->MEMBER = (VALUE);                                           \
4283   spelling++;                                                           \
4284 }
4285
4286 /* Push STRING on the stack.  Printed literally.  */
4287
4288 static void
4289 push_string (const char *string)
4290 {
4291   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4292 }
4293
4294 /* Push a member name on the stack.  Printed as '.' STRING.  */
4295
4296 static void
4297 push_member_name (tree decl)
4298 {
4299   const char *const string
4300     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4301   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4302 }
4303
4304 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4305
4306 static void
4307 push_array_bounds (int bounds)
4308 {
4309   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4310 }
4311
4312 /* Compute the maximum size in bytes of the printed spelling.  */
4313
4314 static int
4315 spelling_length (void)
4316 {
4317   int size = 0;
4318   struct spelling *p;
4319
4320   for (p = spelling_base; p < spelling; p++)
4321     {
4322       if (p->kind == SPELLING_BOUNDS)
4323         size += 25;
4324       else
4325         size += strlen (p->u.s) + 1;
4326     }
4327
4328   return size;
4329 }
4330
4331 /* Print the spelling to BUFFER and return it.  */
4332
4333 static char *
4334 print_spelling (char *buffer)
4335 {
4336   char *d = buffer;
4337   struct spelling *p;
4338
4339   for (p = spelling_base; p < spelling; p++)
4340     if (p->kind == SPELLING_BOUNDS)
4341       {
4342         sprintf (d, "[%d]", p->u.i);
4343         d += strlen (d);
4344       }
4345     else
4346       {
4347         const char *s;
4348         if (p->kind == SPELLING_MEMBER)
4349           *d++ = '.';
4350         for (s = p->u.s; (*d = *s++); d++)
4351           ;
4352       }
4353   *d++ = '\0';
4354   return buffer;
4355 }
4356
4357 /* Issue an error message for a bad initializer component.
4358    MSGID identifies the message.
4359    The component name is taken from the spelling stack.  */
4360
4361 void
4362 error_init (const char *msgid)
4363 {
4364   char *ofwhat;
4365
4366   error ("%s", _(msgid));
4367   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4368   if (*ofwhat)
4369     error ("(near initialization for %qs)", ofwhat);
4370 }
4371
4372 /* Issue a pedantic warning for a bad initializer component.
4373    MSGID identifies the message.
4374    The component name is taken from the spelling stack.  */
4375
4376 void
4377 pedwarn_init (const char *msgid)
4378 {
4379   char *ofwhat;
4380
4381   pedwarn ("%s", _(msgid));
4382   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4383   if (*ofwhat)
4384     pedwarn ("(near initialization for %qs)", ofwhat);
4385 }
4386
4387 /* Issue a warning for a bad initializer component.
4388    MSGID identifies the message.
4389    The component name is taken from the spelling stack.  */
4390
4391 static void
4392 warning_init (const char *msgid)
4393 {
4394   char *ofwhat;
4395
4396   warning (0, "%s", _(msgid));
4397   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4398   if (*ofwhat)
4399     warning (0, "(near initialization for %qs)", ofwhat);
4400 }
4401 \f
4402 /* If TYPE is an array type and EXPR is a parenthesized string
4403    constant, warn if pedantic that EXPR is being used to initialize an
4404    object of type TYPE.  */
4405
4406 void
4407 maybe_warn_string_init (tree type, struct c_expr expr)
4408 {
4409   if (pedantic
4410       && TREE_CODE (type) == ARRAY_TYPE
4411       && TREE_CODE (expr.value) == STRING_CST
4412       && expr.original_code != STRING_CST)
4413     pedwarn_init ("array initialized from parenthesized string constant");
4414 }
4415
4416 /* Digest the parser output INIT as an initializer for type TYPE.
4417    Return a C expression of type TYPE to represent the initial value.
4418
4419    If INIT is a string constant, STRICT_STRING is true if it is
4420    unparenthesized or we should not warn here for it being parenthesized.
4421    For other types of INIT, STRICT_STRING is not used.
4422
4423    REQUIRE_CONSTANT requests an error if non-constant initializers or
4424    elements are seen.  */
4425
4426 static tree
4427 digest_init (tree type, tree init, bool strict_string, int require_constant)
4428 {
4429   enum tree_code code = TREE_CODE (type);
4430   tree inside_init = init;
4431
4432   if (type == error_mark_node
4433       || init == error_mark_node
4434       || TREE_TYPE (init) == error_mark_node)
4435     return error_mark_node;
4436
4437   STRIP_TYPE_NOPS (inside_init);
4438
4439   inside_init = fold (inside_init);
4440
4441   /* Initialization of an array of chars from a string constant
4442      optionally enclosed in braces.  */
4443
4444   if (code == ARRAY_TYPE && inside_init
4445       && TREE_CODE (inside_init) == STRING_CST)
4446     {
4447       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4448       /* Note that an array could be both an array of character type
4449          and an array of wchar_t if wchar_t is signed char or unsigned
4450          char.  */
4451       bool char_array = (typ1 == char_type_node
4452                          || typ1 == signed_char_type_node
4453                          || typ1 == unsigned_char_type_node);
4454       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4455       if (char_array || wchar_array)
4456         {
4457           struct c_expr expr;
4458           bool char_string;
4459           expr.value = inside_init;
4460           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4461           maybe_warn_string_init (type, expr);
4462
4463           char_string
4464             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4465                == char_type_node);
4466
4467           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4468                          TYPE_MAIN_VARIANT (type)))
4469             return inside_init;
4470
4471           if (!wchar_array && !char_string)
4472             {
4473               error_init ("char-array initialized from wide string");
4474               return error_mark_node;
4475             }
4476           if (char_string && !char_array)
4477             {
4478               error_init ("wchar_t-array initialized from non-wide string");
4479               return error_mark_node;
4480             }
4481
4482           TREE_TYPE (inside_init) = type;
4483           if (TYPE_DOMAIN (type) != 0
4484               && TYPE_SIZE (type) != 0
4485               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4486               /* Subtract 1 (or sizeof (wchar_t))
4487                  because it's ok to ignore the terminating null char
4488                  that is counted in the length of the constant.  */
4489               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4490                                        TREE_STRING_LENGTH (inside_init)
4491                                        - ((TYPE_PRECISION (typ1)
4492                                            != TYPE_PRECISION (char_type_node))
4493                                           ? (TYPE_PRECISION (wchar_type_node)
4494                                              / BITS_PER_UNIT)
4495                                           : 1)))
4496             pedwarn_init ("initializer-string for array of chars is too long");
4497
4498           return inside_init;
4499         }
4500       else if (INTEGRAL_TYPE_P (typ1))
4501         {
4502           error_init ("array of inappropriate type initialized "
4503                       "from string constant");
4504           return error_mark_node;
4505         }
4506     }
4507
4508   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4509      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4510      below and handle as a constructor.  */
4511   if (code == VECTOR_TYPE
4512       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4513       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4514       && TREE_CONSTANT (inside_init))
4515     {
4516       if (TREE_CODE (inside_init) == VECTOR_CST
4517           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4518                         TYPE_MAIN_VARIANT (type)))
4519         return inside_init;
4520
4521       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4522         {
4523           unsigned HOST_WIDE_INT ix;
4524           tree value;
4525           bool constant_p = true;
4526
4527           /* Iterate through elements and check if all constructor
4528              elements are *_CSTs.  */
4529           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4530             if (!CONSTANT_CLASS_P (value))
4531               {
4532                 constant_p = false;
4533                 break;
4534               }
4535
4536           if (constant_p)
4537             return build_vector_from_ctor (type,
4538                                            CONSTRUCTOR_ELTS (inside_init));
4539         }
4540     }
4541
4542   /* Any type can be initialized
4543      from an expression of the same type, optionally with braces.  */
4544
4545   if (inside_init && TREE_TYPE (inside_init) != 0
4546       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4547                      TYPE_MAIN_VARIANT (type))
4548           || (code == ARRAY_TYPE
4549               && comptypes (TREE_TYPE (inside_init), type))
4550           || (code == VECTOR_TYPE
4551               && comptypes (TREE_TYPE (inside_init), type))
4552           || (code == POINTER_TYPE
4553               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4554               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4555                             TREE_TYPE (type)))))
4556     {
4557       if (code == POINTER_TYPE)
4558         {
4559           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4560             {
4561               if (TREE_CODE (inside_init) == STRING_CST
4562                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4563                 inside_init = array_to_pointer_conversion (inside_init);
4564               else
4565                 {
4566                   error_init ("invalid use of non-lvalue array");
4567                   return error_mark_node;
4568                 }
4569             }
4570         }
4571
4572       if (code == VECTOR_TYPE)
4573         /* Although the types are compatible, we may require a
4574            conversion.  */
4575         inside_init = convert (type, inside_init);
4576
4577       if (require_constant && !flag_isoc99
4578           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4579         {
4580           /* As an extension, allow initializing objects with static storage
4581              duration with compound literals (which are then treated just as
4582              the brace enclosed list they contain).  */
4583           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4584           inside_init = DECL_INITIAL (decl);
4585         }
4586
4587       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4588           && TREE_CODE (inside_init) != CONSTRUCTOR)
4589         {
4590           error_init ("array initialized from non-constant array expression");
4591           return error_mark_node;
4592         }
4593
4594       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4595         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4596
4597       /* Compound expressions can only occur here if -pedantic or
4598          -pedantic-errors is specified.  In the later case, we always want
4599          an error.  In the former case, we simply want a warning.  */
4600       if (require_constant && pedantic
4601           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4602         {
4603           inside_init
4604             = valid_compound_expr_initializer (inside_init,
4605                                                TREE_TYPE (inside_init));
4606           if (inside_init == error_mark_node)
4607             error_init ("initializer element is not constant");
4608           else
4609             pedwarn_init ("initializer element is not constant");
4610           if (flag_pedantic_errors)
4611             inside_init = error_mark_node;
4612         }
4613       else if (require_constant
4614                && !initializer_constant_valid_p (inside_init,
4615                                                  TREE_TYPE (inside_init)))
4616         {
4617           error_init ("initializer element is not constant");
4618           inside_init = error_mark_node;
4619         }
4620
4621       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4622       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4623         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4624                                               NULL_TREE, 0);
4625       return inside_init;
4626     }
4627
4628   /* Handle scalar types, including conversions.  */
4629
4630   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4631       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4632       || code == VECTOR_TYPE)
4633     {
4634       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4635           && (TREE_CODE (init) == STRING_CST
4636               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4637         init = array_to_pointer_conversion (init);
4638       inside_init
4639         = convert_for_assignment (type, init, ic_init,
4640                                   NULL_TREE, NULL_TREE, 0);
4641
4642       /* Check to see if we have already given an error message.  */
4643       if (inside_init == error_mark_node)
4644         ;
4645       else if (require_constant && !TREE_CONSTANT (inside_init))
4646         {
4647           error_init ("initializer element is not constant");
4648           inside_init = error_mark_node;
4649         }
4650       else if (require_constant
4651                && !initializer_constant_valid_p (inside_init,
4652                                                  TREE_TYPE (inside_init)))
4653         {
4654           error_init ("initializer element is not computable at load time");
4655           inside_init = error_mark_node;
4656         }
4657
4658       return inside_init;
4659     }
4660
4661   /* Come here only for records and arrays.  */
4662
4663   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4664     {
4665       error_init ("variable-sized object may not be initialized");
4666       return error_mark_node;
4667     }
4668
4669   error_init ("invalid initializer");
4670   return error_mark_node;
4671 }
4672 \f
4673 /* Handle initializers that use braces.  */
4674
4675 /* Type of object we are accumulating a constructor for.
4676    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4677 static tree constructor_type;
4678
4679 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4680    left to fill.  */
4681 static tree constructor_fields;
4682
4683 /* For an ARRAY_TYPE, this is the specified index
4684    at which to store the next element we get.  */
4685 static tree constructor_index;
4686
4687 /* For an ARRAY_TYPE, this is the maximum index.  */
4688 static tree constructor_max_index;
4689
4690 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4691 static tree constructor_unfilled_fields;
4692
4693 /* For an ARRAY_TYPE, this is the index of the first element
4694    not yet written out.  */
4695 static tree constructor_unfilled_index;
4696
4697 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4698    This is so we can generate gaps between fields, when appropriate.  */
4699 static tree constructor_bit_index;
4700
4701 /* If we are saving up the elements rather than allocating them,
4702    this is the list of elements so far (in reverse order,
4703    most recent first).  */
4704 static VEC(constructor_elt,gc) *constructor_elements;
4705
4706 /* 1 if constructor should be incrementally stored into a constructor chain,
4707    0 if all the elements should be kept in AVL tree.  */
4708 static int constructor_incremental;
4709
4710 /* 1 if so far this constructor's elements are all compile-time constants.  */
4711 static int constructor_constant;
4712
4713 /* 1 if so far this constructor's elements are all valid address constants.  */
4714 static int constructor_simple;
4715
4716 /* 1 if this constructor is erroneous so far.  */
4717 static int constructor_erroneous;
4718
4719 /* Structure for managing pending initializer elements, organized as an
4720    AVL tree.  */
4721
4722 struct init_node
4723 {
4724   struct init_node *left, *right;
4725   struct init_node *parent;
4726   int balance;
4727   tree purpose;
4728   tree value;
4729 };
4730
4731 /* Tree of pending elements at this constructor level.
4732    These are elements encountered out of order
4733    which belong at places we haven't reached yet in actually
4734    writing the output.
4735    Will never hold tree nodes across GC runs.  */
4736 static struct init_node *constructor_pending_elts;
4737
4738 /* The SPELLING_DEPTH of this constructor.  */
4739 static int constructor_depth;
4740
4741 /* DECL node for which an initializer is being read.
4742    0 means we are reading a constructor expression
4743    such as (struct foo) {...}.  */
4744 static tree constructor_decl;
4745
4746 /* Nonzero if this is an initializer for a top-level decl.  */
4747 static int constructor_top_level;
4748
4749 /* Nonzero if there were any member designators in this initializer.  */
4750 static int constructor_designated;
4751
4752 /* Nesting depth of designator list.  */
4753 static int designator_depth;
4754
4755 /* Nonzero if there were diagnosed errors in this designator list.  */
4756 static int designator_erroneous;
4757
4758 \f
4759 /* This stack has a level for each implicit or explicit level of
4760    structuring in the initializer, including the outermost one.  It
4761    saves the values of most of the variables above.  */
4762
4763 struct constructor_range_stack;
4764
4765 struct constructor_stack
4766 {
4767   struct constructor_stack *next;
4768   tree type;
4769   tree fields;
4770   tree index;
4771   tree max_index;
4772   tree unfilled_index;
4773   tree unfilled_fields;
4774   tree bit_index;
4775   VEC(constructor_elt,gc) *elements;
4776   struct init_node *pending_elts;
4777   int offset;
4778   int depth;
4779   /* If value nonzero, this value should replace the entire
4780      constructor at this level.  */
4781   struct c_expr replacement_value;
4782   struct constructor_range_stack *range_stack;
4783   char constant;
4784   char simple;
4785   char implicit;
4786   char erroneous;
4787   char outer;
4788   char incremental;
4789   char designated;
4790 };
4791
4792 static struct constructor_stack *constructor_stack;
4793
4794 /* This stack represents designators from some range designator up to
4795    the last designator in the list.  */
4796
4797 struct constructor_range_stack
4798 {
4799   struct constructor_range_stack *next, *prev;
4800   struct constructor_stack *stack;
4801   tree range_start;
4802   tree index;
4803   tree range_end;
4804   tree fields;
4805 };
4806
4807 static struct constructor_range_stack *constructor_range_stack;
4808
4809 /* This stack records separate initializers that are nested.
4810    Nested initializers can't happen in ANSI C, but GNU C allows them
4811    in cases like { ... (struct foo) { ... } ... }.  */
4812
4813 struct initializer_stack
4814 {
4815   struct initializer_stack *next;
4816   tree decl;
4817   struct constructor_stack *constructor_stack;
4818   struct constructor_range_stack *constructor_range_stack;
4819   VEC(constructor_elt,gc) *elements;
4820   struct spelling *spelling;
4821   struct spelling *spelling_base;
4822   int spelling_size;
4823   char top_level;
4824   char require_constant_value;
4825   char require_constant_elements;
4826 };
4827
4828 static struct initializer_stack *initializer_stack;
4829 \f
4830 /* Prepare to parse and output the initializer for variable DECL.  */
4831
4832 void
4833 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4834 {
4835   const char *locus;
4836   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4837
4838   p->decl = constructor_decl;
4839   p->require_constant_value = require_constant_value;
4840   p->require_constant_elements = require_constant_elements;
4841   p->constructor_stack = constructor_stack;
4842   p->constructor_range_stack = constructor_range_stack;
4843   p->elements = constructor_elements;
4844   p->spelling = spelling;
4845   p->spelling_base = spelling_base;
4846   p->spelling_size = spelling_size;
4847   p->top_level = constructor_top_level;
4848   p->next = initializer_stack;
4849   initializer_stack = p;
4850
4851   constructor_decl = decl;
4852   constructor_designated = 0;
4853   constructor_top_level = top_level;
4854
4855   if (decl != 0 && decl != error_mark_node)
4856     {
4857       require_constant_value = TREE_STATIC (decl);
4858       require_constant_elements
4859         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4860            /* For a scalar, you can always use any value to initialize,
4861               even within braces.  */
4862            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4863                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4864                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4865                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4866       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4867     }
4868   else
4869     {
4870       require_constant_value = 0;
4871       require_constant_elements = 0;
4872       locus = "(anonymous)";
4873     }
4874
4875   constructor_stack = 0;
4876   constructor_range_stack = 0;
4877
4878   missing_braces_mentioned = 0;
4879
4880   spelling_base = 0;
4881   spelling_size = 0;
4882   RESTORE_SPELLING_DEPTH (0);
4883
4884   if (locus)
4885     push_string (locus);
4886 }
4887
4888 void
4889 finish_init (void)
4890 {
4891   struct initializer_stack *p = initializer_stack;
4892
4893   /* Free the whole constructor stack of this initializer.  */
4894   while (constructor_stack)
4895     {
4896       struct constructor_stack *q = constructor_stack;
4897       constructor_stack = q->next;
4898       free (q);
4899     }
4900
4901   gcc_assert (!constructor_range_stack);
4902
4903   /* Pop back to the data of the outer initializer (if any).  */
4904   free (spelling_base);
4905
4906   constructor_decl = p->decl;
4907   require_constant_value = p->require_constant_value;
4908   require_constant_elements = p->require_constant_elements;
4909   constructor_stack = p->constructor_stack;
4910   constructor_range_stack = p->constructor_range_stack;
4911   constructor_elements = p->elements;
4912   spelling = p->spelling;
4913   spelling_base = p->spelling_base;
4914   spelling_size = p->spelling_size;
4915   constructor_top_level = p->top_level;
4916   initializer_stack = p->next;
4917   free (p);
4918 }
4919 \f
4920 /* Call here when we see the initializer is surrounded by braces.
4921    This is instead of a call to push_init_level;
4922    it is matched by a call to pop_init_level.
4923
4924    TYPE is the type to initialize, for a constructor expression.
4925    For an initializer for a decl, TYPE is zero.  */
4926
4927 void
4928 really_start_incremental_init (tree type)
4929 {
4930   struct constructor_stack *p = XNEW (struct constructor_stack);
4931
4932   if (type == 0)
4933     type = TREE_TYPE (constructor_decl);
4934
4935   if (targetm.vector_opaque_p (type))
4936     error ("opaque vector types cannot be initialized");
4937
4938   p->type = constructor_type;
4939   p->fields = constructor_fields;
4940   p->index = constructor_index;
4941   p->max_index = constructor_max_index;
4942   p->unfilled_index = constructor_unfilled_index;
4943   p->unfilled_fields = constructor_unfilled_fields;
4944   p->bit_index = constructor_bit_index;
4945   p->elements = constructor_elements;
4946   p->constant = constructor_constant;
4947   p->simple = constructor_simple;
4948   p->erroneous = constructor_erroneous;
4949   p->pending_elts = constructor_pending_elts;
4950   p->depth = constructor_depth;
4951   p->replacement_value.value = 0;
4952   p->replacement_value.original_code = ERROR_MARK;
4953   p->implicit = 0;
4954   p->range_stack = 0;
4955   p->outer = 0;
4956   p->incremental = constructor_incremental;
4957   p->designated = constructor_designated;
4958   p->next = 0;
4959   constructor_stack = p;
4960
4961   constructor_constant = 1;
4962   constructor_simple = 1;
4963   constructor_depth = SPELLING_DEPTH ();
4964   constructor_elements = 0;
4965   constructor_pending_elts = 0;
4966   constructor_type = type;
4967   constructor_incremental = 1;
4968   constructor_designated = 0;
4969   designator_depth = 0;
4970   designator_erroneous = 0;
4971
4972   if (TREE_CODE (constructor_type) == RECORD_TYPE
4973       || TREE_CODE (constructor_type) == UNION_TYPE)
4974     {
4975       constructor_fields = TYPE_FIELDS (constructor_type);
4976       /* Skip any nameless bit fields at the beginning.  */
4977       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4978              && DECL_NAME (constructor_fields) == 0)
4979         constructor_fields = TREE_CHAIN (constructor_fields);
4980
4981       constructor_unfilled_fields = constructor_fields;
4982       constructor_bit_index = bitsize_zero_node;
4983     }
4984   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4985     {
4986       if (TYPE_DOMAIN (constructor_type))
4987         {
4988           constructor_max_index
4989             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4990
4991           /* Detect non-empty initializations of zero-length arrays.  */
4992           if (constructor_max_index == NULL_TREE
4993               && TYPE_SIZE (constructor_type))
4994             constructor_max_index = build_int_cst (NULL_TREE, -1);
4995
4996           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4997              to initialize VLAs will cause a proper error; avoid tree
4998              checking errors as well by setting a safe value.  */
4999           if (constructor_max_index
5000               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5001             constructor_max_index = build_int_cst (NULL_TREE, -1);
5002
5003           constructor_index
5004             = convert (bitsizetype,
5005                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5006         }
5007       else
5008         {
5009           constructor_index = bitsize_zero_node;
5010           constructor_max_index = NULL_TREE;
5011         }
5012
5013       constructor_unfilled_index = constructor_index;
5014     }
5015   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5016     {
5017       /* Vectors are like simple fixed-size arrays.  */
5018       constructor_max_index =
5019         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5020       constructor_index = convert (bitsizetype, bitsize_zero_node);
5021       constructor_unfilled_index = constructor_index;
5022     }
5023   else
5024     {
5025       /* Handle the case of int x = {5}; */
5026       constructor_fields = constructor_type;
5027       constructor_unfilled_fields = constructor_type;
5028     }
5029 }
5030 \f
5031 /* Push down into a subobject, for initialization.
5032    If this is for an explicit set of braces, IMPLICIT is 0.
5033    If it is because the next element belongs at a lower level,
5034    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5035
5036 void
5037 push_init_level (int implicit)
5038 {
5039   struct constructor_stack *p;
5040   tree value = NULL_TREE;
5041
5042   /* If we've exhausted any levels that didn't have braces,
5043      pop them now.  If implicit == 1, this will have been done in
5044      process_init_element; do not repeat it here because in the case
5045      of excess initializers for an empty aggregate this leads to an
5046      infinite cycle of popping a level and immediately recreating
5047      it.  */
5048   if (implicit != 1)
5049     {
5050       while (constructor_stack->implicit)
5051         {
5052           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5053                || TREE_CODE (constructor_type) == UNION_TYPE)
5054               && constructor_fields == 0)
5055             process_init_element (pop_init_level (1));
5056           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5057                    && constructor_max_index
5058                    && tree_int_cst_lt (constructor_max_index,
5059                                        constructor_index))
5060             process_init_element (pop_init_level (1));
5061           else
5062             break;
5063         }
5064     }
5065
5066   /* Unless this is an explicit brace, we need to preserve previous
5067      content if any.  */
5068   if (implicit)
5069     {
5070       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5071            || TREE_CODE (constructor_type) == UNION_TYPE)
5072           && constructor_fields)
5073         value = find_init_member (constructor_fields);
5074       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5075         value = find_init_member (constructor_index);
5076     }
5077
5078   p = XNEW (struct constructor_stack);
5079   p->type = constructor_type;
5080   p->fields = constructor_fields;
5081   p->index = constructor_index;
5082   p->max_index = constructor_max_index;
5083   p->unfilled_index = constructor_unfilled_index;
5084   p->unfilled_fields = constructor_unfilled_fields;
5085   p->bit_index = constructor_bit_index;
5086   p->elements = constructor_elements;
5087   p->constant = constructor_constant;
5088   p->simple = constructor_simple;
5089   p->erroneous = constructor_erroneous;
5090   p->pending_elts = constructor_pending_elts;
5091   p->depth = constructor_depth;
5092   p->replacement_value.value = 0;
5093   p->replacement_value.original_code = ERROR_MARK;
5094   p->implicit = implicit;
5095   p->outer = 0;
5096   p->incremental = constructor_incremental;
5097   p->designated = constructor_designated;
5098   p->next = constructor_stack;
5099   p->range_stack = 0;
5100   constructor_stack = p;
5101
5102   constructor_constant = 1;
5103   constructor_simple = 1;
5104   constructor_depth = SPELLING_DEPTH ();
5105   constructor_elements = 0;
5106   constructor_incremental = 1;
5107   constructor_designated = 0;
5108   constructor_pending_elts = 0;
5109   if (!implicit)
5110     {
5111       p->range_stack = constructor_range_stack;
5112       constructor_range_stack = 0;
5113       designator_depth = 0;
5114       designator_erroneous = 0;
5115     }
5116
5117   /* Don't die if an entire brace-pair level is superfluous
5118      in the containing level.  */
5119   if (constructor_type == 0)
5120     ;
5121   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5122            || TREE_CODE (constructor_type) == UNION_TYPE)
5123     {
5124       /* Don't die if there are extra init elts at the end.  */
5125       if (constructor_fields == 0)
5126         constructor_type = 0;
5127       else
5128         {
5129           constructor_type = TREE_TYPE (constructor_fields);
5130           push_member_name (constructor_fields);
5131           constructor_depth++;
5132         }
5133     }
5134   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5135     {
5136       constructor_type = TREE_TYPE (constructor_type);
5137       push_array_bounds (tree_low_cst (constructor_index, 0));
5138       constructor_depth++;
5139     }
5140
5141   if (constructor_type == 0)
5142     {
5143       error_init ("extra brace group at end of initializer");
5144       constructor_fields = 0;
5145       constructor_unfilled_fields = 0;
5146       return;
5147     }
5148
5149   if (value && TREE_CODE (value) == CONSTRUCTOR)
5150     {
5151       constructor_constant = TREE_CONSTANT (value);
5152       constructor_simple = TREE_STATIC (value);
5153       constructor_elements = CONSTRUCTOR_ELTS (value);
5154       if (!VEC_empty (constructor_elt, constructor_elements)
5155           && (TREE_CODE (constructor_type) == RECORD_TYPE
5156               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5157         set_nonincremental_init ();
5158     }
5159
5160   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5161     {
5162       missing_braces_mentioned = 1;
5163       warning_init ("missing braces around initializer");
5164     }
5165
5166   if (TREE_CODE (constructor_type) == RECORD_TYPE
5167            || TREE_CODE (constructor_type) == UNION_TYPE)
5168     {
5169       constructor_fields = TYPE_FIELDS (constructor_type);
5170       /* Skip any nameless bit fields at the beginning.  */
5171       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5172              && DECL_NAME (constructor_fields) == 0)
5173         constructor_fields = TREE_CHAIN (constructor_fields);
5174
5175       constructor_unfilled_fields = constructor_fields;
5176       constructor_bit_index = bitsize_zero_node;
5177     }
5178   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5179     {
5180       /* Vectors are like simple fixed-size arrays.  */
5181       constructor_max_index =
5182         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5183       constructor_index = convert (bitsizetype, integer_zero_node);
5184       constructor_unfilled_index = constructor_index;
5185     }
5186   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5187     {
5188       if (TYPE_DOMAIN (constructor_type))
5189         {
5190           constructor_max_index
5191             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5192
5193           /* Detect non-empty initializations of zero-length arrays.  */
5194           if (constructor_max_index == NULL_TREE
5195               && TYPE_SIZE (constructor_type))
5196             constructor_max_index = build_int_cst (NULL_TREE, -1);
5197
5198           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5199              to initialize VLAs will cause a proper error; avoid tree
5200              checking errors as well by setting a safe value.  */
5201           if (constructor_max_index
5202               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5203             constructor_max_index = build_int_cst (NULL_TREE, -1);
5204
5205           constructor_index
5206             = convert (bitsizetype,
5207                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5208         }
5209       else
5210         constructor_index = bitsize_zero_node;
5211
5212       constructor_unfilled_index = constructor_index;
5213       if (value && TREE_CODE (value) == STRING_CST)
5214         {
5215           /* We need to split the char/wchar array into individual
5216              characters, so that we don't have to special case it
5217              everywhere.  */
5218           set_nonincremental_init_from_string (value);
5219         }
5220     }
5221   else
5222     {
5223       if (constructor_type != error_mark_node)
5224         warning_init ("braces around scalar initializer");
5225       constructor_fields = constructor_type;
5226       constructor_unfilled_fields = constructor_type;
5227     }
5228 }
5229
5230 /* At the end of an implicit or explicit brace level,
5231    finish up that level of constructor.  If a single expression
5232    with redundant braces initialized that level, return the
5233    c_expr structure for that expression.  Otherwise, the original_code
5234    element is set to ERROR_MARK.
5235    If we were outputting the elements as they are read, return 0 as the value
5236    from inner levels (process_init_element ignores that),
5237    but return error_mark_node as the value from the outermost level
5238    (that's what we want to put in DECL_INITIAL).
5239    Otherwise, return a CONSTRUCTOR expression as the value.  */
5240
5241 struct c_expr
5242 pop_init_level (int implicit)
5243 {
5244   struct constructor_stack *p;
5245   struct c_expr ret;
5246   ret.value = 0;
5247   ret.original_code = ERROR_MARK;
5248
5249   if (implicit == 0)
5250     {
5251       /* When we come to an explicit close brace,
5252          pop any inner levels that didn't have explicit braces.  */
5253       while (constructor_stack->implicit)
5254         process_init_element (pop_init_level (1));
5255
5256       gcc_assert (!constructor_range_stack);
5257     }
5258
5259   /* Now output all pending elements.  */
5260   constructor_incremental = 1;
5261   output_pending_init_elements (1);
5262
5263   p = constructor_stack;
5264
5265   /* Error for initializing a flexible array member, or a zero-length
5266      array member in an inappropriate context.  */
5267   if (constructor_type && constructor_fields
5268       && TREE_CODE (constructor_type) == ARRAY_TYPE
5269       && TYPE_DOMAIN (constructor_type)
5270       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5271     {
5272       /* Silently discard empty initializations.  The parser will
5273          already have pedwarned for empty brackets.  */
5274       if (integer_zerop (constructor_unfilled_index))
5275         constructor_type = NULL_TREE;
5276       else
5277         {
5278           gcc_assert (!TYPE_SIZE (constructor_type));
5279
5280           if (constructor_depth > 2)
5281             error_init ("initialization of flexible array member in a nested context");
5282           else if (pedantic)
5283             pedwarn_init ("initialization of a flexible array member");
5284
5285           /* We have already issued an error message for the existence
5286              of a flexible array member not at the end of the structure.
5287              Discard the initializer so that we do not die later.  */
5288           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5289             constructor_type = NULL_TREE;
5290         }
5291     }
5292
5293   /* Warn when some struct elements are implicitly initialized to zero.  */
5294   if (warn_missing_field_initializers
5295       && constructor_type
5296       && TREE_CODE (constructor_type) == RECORD_TYPE
5297       && constructor_unfilled_fields)
5298     {
5299         /* Do not warn for flexible array members or zero-length arrays.  */
5300         while (constructor_unfilled_fields
5301                && (!DECL_SIZE (constructor_unfilled_fields)
5302                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5303           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5304
5305         /* Do not warn if this level of the initializer uses member
5306            designators; it is likely to be deliberate.  */
5307         if (constructor_unfilled_fields && !constructor_designated)
5308           {
5309             push_member_name (constructor_unfilled_fields);
5310             warning_init ("missing initializer");
5311             RESTORE_SPELLING_DEPTH (constructor_depth);
5312           }
5313     }
5314
5315   /* Pad out the end of the structure.  */
5316   if (p->replacement_value.value)
5317     /* If this closes a superfluous brace pair,
5318        just pass out the element between them.  */
5319     ret = p->replacement_value;
5320   else if (constructor_type == 0)
5321     ;
5322   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5323            && TREE_CODE (constructor_type) != UNION_TYPE
5324            && TREE_CODE (constructor_type) != ARRAY_TYPE
5325            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5326     {
5327       /* A nonincremental scalar initializer--just return
5328          the element, after verifying there is just one.  */
5329       if (VEC_empty (constructor_elt,constructor_elements))
5330         {
5331           if (!constructor_erroneous)
5332             error_init ("empty scalar initializer");
5333           ret.value = error_mark_node;
5334         }
5335       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5336         {
5337           error_init ("extra elements in scalar initializer");
5338           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5339         }
5340       else
5341         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5342     }
5343   else
5344     {
5345       if (constructor_erroneous)
5346         ret.value = error_mark_node;
5347       else
5348         {
5349           ret.value = build_constructor (constructor_type,
5350                                          constructor_elements);
5351           if (constructor_constant)
5352             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5353           if (constructor_constant && constructor_simple)
5354             TREE_STATIC (ret.value) = 1;
5355         }
5356     }
5357
5358   constructor_type = p->type;
5359   constructor_fields = p->fields;
5360   constructor_index = p->index;
5361   constructor_max_index = p->max_index;
5362   constructor_unfilled_index = p->unfilled_index;
5363   constructor_unfilled_fields = p->unfilled_fields;
5364   constructor_bit_index = p->bit_index;
5365   constructor_elements = p->elements;
5366   constructor_constant = p->constant;
5367   constructor_simple = p->simple;
5368   constructor_erroneous = p->erroneous;
5369   constructor_incremental = p->incremental;
5370   constructor_designated = p->designated;
5371   constructor_pending_elts = p->pending_elts;
5372   constructor_depth = p->depth;
5373   if (!p->implicit)
5374     constructor_range_stack = p->range_stack;
5375   RESTORE_SPELLING_DEPTH (constructor_depth);
5376
5377   constructor_stack = p->next;
5378   free (p);
5379
5380   if (ret.value == 0)
5381     {
5382       if (constructor_stack == 0)
5383         {
5384           ret.value = error_mark_node;
5385           return ret;
5386         }
5387       return ret;
5388     }
5389   return ret;
5390 }
5391
5392 /* Common handling for both array range and field name designators.
5393    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5394
5395 static int
5396 set_designator (int array)
5397 {
5398   tree subtype;
5399   enum tree_code subcode;
5400
5401   /* Don't die if an entire brace-pair level is superfluous
5402      in the containing level.  */
5403   if (constructor_type == 0)
5404     return 1;
5405
5406   /* If there were errors in this designator list already, bail out
5407      silently.  */
5408   if (designator_erroneous)
5409     return 1;
5410
5411   if (!designator_depth)
5412     {
5413       gcc_assert (!constructor_range_stack);
5414
5415       /* Designator list starts at the level of closest explicit
5416          braces.  */
5417       while (constructor_stack->implicit)
5418         process_init_element (pop_init_level (1));
5419       constructor_designated = 1;
5420       return 0;
5421     }
5422
5423   switch (TREE_CODE (constructor_type))
5424     {
5425     case  RECORD_TYPE:
5426     case  UNION_TYPE:
5427       subtype = TREE_TYPE (constructor_fields);
5428       if (subtype != error_mark_node)
5429         subtype = TYPE_MAIN_VARIANT (subtype);
5430       break;
5431     case ARRAY_TYPE:
5432       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5433       break;
5434     default:
5435       gcc_unreachable ();
5436     }
5437
5438   subcode = TREE_CODE (subtype);
5439   if (array && subcode != ARRAY_TYPE)
5440     {
5441       error_init ("array index in non-array initializer");
5442       return 1;
5443     }
5444   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5445     {
5446       error_init ("field name not in record or union initializer");
5447       return 1;
5448     }
5449
5450   constructor_designated = 1;
5451   push_init_level (2);
5452   return 0;
5453 }
5454
5455 /* If there are range designators in designator list, push a new designator
5456    to constructor_range_stack.  RANGE_END is end of such stack range or
5457    NULL_TREE if there is no range designator at this level.  */
5458
5459 static void
5460 push_range_stack (tree range_end)
5461 {
5462   struct constructor_range_stack *p;
5463
5464   p = GGC_NEW (struct constructor_range_stack);
5465   p->prev = constructor_range_stack;
5466   p->next = 0;
5467   p->fields = constructor_fields;
5468   p->range_start = constructor_index;
5469   p->index = constructor_index;
5470   p->stack = constructor_stack;
5471   p->range_end = range_end;
5472   if (constructor_range_stack)
5473     constructor_range_stack->next = p;
5474   constructor_range_stack = p;
5475 }
5476
5477 /* Within an array initializer, specify the next index to be initialized.
5478    FIRST is that index.  If LAST is nonzero, then initialize a range
5479    of indices, running from FIRST through LAST.  */
5480
5481 void
5482 set_init_index (tree first, tree last)
5483 {
5484   if (set_designator (1))
5485     return;
5486
5487   designator_erroneous = 1;
5488
5489   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5490       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5491     {
5492       error_init ("array index in initializer not of integer type");
5493       return;
5494     }
5495
5496   if (TREE_CODE (first) != INTEGER_CST)
5497     error_init ("nonconstant array index in initializer");
5498   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5499     error_init ("nonconstant array index in initializer");
5500   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5501     error_init ("array index in non-array initializer");
5502   else if (tree_int_cst_sgn (first) == -1)
5503     error_init ("array index in initializer exceeds array bounds");
5504   else if (constructor_max_index
5505            && tree_int_cst_lt (constructor_max_index, first))
5506     error_init ("array index in initializer exceeds array bounds");
5507   else
5508     {
5509       constructor_index = convert (bitsizetype, first);
5510
5511       if (last)
5512         {
5513           if (tree_int_cst_equal (first, last))
5514             last = 0;
5515           else if (tree_int_cst_lt (last, first))
5516             {
5517               error_init ("empty index range in initializer");
5518               last = 0;
5519             }
5520           else
5521             {
5522               last = convert (bitsizetype, last);
5523               if (constructor_max_index != 0
5524                   && tree_int_cst_lt (constructor_max_index, last))
5525                 {
5526                   error_init ("array index range in initializer exceeds array bounds");
5527                   last = 0;
5528                 }
5529             }
5530         }
5531
5532       designator_depth++;
5533       designator_erroneous = 0;
5534       if (constructor_range_stack || last)
5535         push_range_stack (last);
5536     }
5537 }
5538
5539 /* Within a struct initializer, specify the next field to be initialized.  */
5540
5541 void
5542 set_init_label (tree fieldname)
5543 {
5544   tree tail;
5545
5546   if (set_designator (0))
5547     return;
5548
5549   designator_erroneous = 1;
5550
5551   if (TREE_CODE (constructor_type) != RECORD_TYPE
5552       && TREE_CODE (constructor_type) != UNION_TYPE)
5553     {
5554       error_init ("field name not in record or union initializer");
5555       return;
5556     }
5557
5558   for (tail = TYPE_FIELDS (constructor_type); tail;
5559        tail = TREE_CHAIN (tail))
5560     {
5561       if (DECL_NAME (tail) == fieldname)
5562         break;
5563     }
5564
5565   if (tail == 0)
5566     error ("unknown field %qE specified in initializer", fieldname);
5567   else
5568     {
5569       constructor_fields = tail;
5570       designator_depth++;
5571       designator_erroneous = 0;
5572       if (constructor_range_stack)
5573         push_range_stack (NULL_TREE);
5574     }
5575 }
5576 \f
5577 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5578    identifies the initializer, either array index or field in a structure.
5579    VALUE is the value of that index or field.  */
5580
5581 static void
5582 add_pending_init (tree purpose, tree value)
5583 {
5584   struct init_node *p, **q, *r;
5585
5586   q = &constructor_pending_elts;
5587   p = 0;
5588
5589   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5590     {
5591       while (*q != 0)
5592         {
5593           p = *q;
5594           if (tree_int_cst_lt (purpose, p->purpose))
5595             q = &p->left;
5596           else if (tree_int_cst_lt (p->purpose, purpose))
5597             q = &p->right;
5598           else
5599             {
5600               if (TREE_SIDE_EFFECTS (p->value))
5601                 warning_init ("initialized field with side-effects overwritten");
5602               p->value = value;
5603               return;
5604             }
5605         }
5606     }
5607   else
5608     {
5609       tree bitpos;
5610
5611       bitpos = bit_position (purpose);
5612       while (*q != NULL)
5613         {
5614           p = *q;
5615           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5616             q = &p->left;
5617           else if (p->purpose != purpose)
5618             q = &p->right;
5619           else
5620             {
5621               if (TREE_SIDE_EFFECTS (p->value))
5622                 warning_init ("initialized field with side-effects overwritten");
5623               p->value = value;
5624               return;
5625             }
5626         }
5627     }
5628
5629   r = GGC_NEW (struct init_node);
5630   r->purpose = purpose;
5631   r->value = value;
5632
5633   *q = r;
5634   r->parent = p;
5635   r->left = 0;
5636   r->right = 0;
5637   r->balance = 0;
5638
5639   while (p)
5640     {
5641       struct init_node *s;
5642
5643       if (r == p->left)
5644         {
5645           if (p->balance == 0)
5646             p->balance = -1;
5647           else if (p->balance < 0)
5648             {
5649               if (r->balance < 0)
5650                 {
5651                   /* L rotation.  */
5652                   p->left = r->right;
5653                   if (p->left)
5654                     p->left->parent = p;
5655                   r->right = p;
5656
5657                   p->balance = 0;
5658                   r->balance = 0;
5659
5660                   s = p->parent;
5661                   p->parent = r;
5662                   r->parent = s;
5663                   if (s)
5664                     {
5665                       if (s->left == p)
5666                         s->left = r;
5667                       else
5668                         s->right = r;
5669                     }
5670                   else
5671                     constructor_pending_elts = r;
5672                 }
5673               else
5674                 {
5675                   /* LR rotation.  */
5676                   struct init_node *t = r->right;
5677
5678                   r->right = t->left;
5679                   if (r->right)
5680                     r->right->parent = r;
5681                   t->left = r;
5682
5683                   p->left = t->right;
5684                   if (p->left)
5685                     p->left->parent = p;
5686                   t->right = p;
5687
5688                   p->balance = t->balance < 0;
5689                   r->balance = -(t->balance > 0);
5690                   t->balance = 0;
5691
5692                   s = p->parent;
5693                   p->parent = t;
5694                   r->parent = t;
5695                   t->parent = s;
5696                   if (s)
5697                     {
5698                       if (s->left == p)
5699                         s->left = t;
5700                       else
5701                         s->right = t;
5702                     }
5703                   else
5704                     constructor_pending_elts = t;
5705                 }
5706               break;
5707             }
5708           else
5709             {
5710               /* p->balance == +1; growth of left side balances the node.  */
5711               p->balance = 0;
5712               break;
5713             }
5714         }
5715       else /* r == p->right */
5716         {
5717           if (p->balance == 0)
5718             /* Growth propagation from right side.  */
5719             p->balance++;
5720           else if (p->balance > 0)
5721             {
5722               if (r->balance > 0)
5723                 {
5724                   /* R rotation.  */
5725                   p->right = r->left;
5726                   if (p->right)
5727                     p->right->parent = p;
5728                   r->left = p;
5729
5730                   p->balance = 0;
5731                   r->balance = 0;
5732
5733                   s = p->parent;
5734                   p->parent = r;
5735                   r->parent = s;
5736                   if (s)
5737                     {
5738                       if (s->left == p)
5739                         s->left = r;
5740                       else
5741                         s->right = r;
5742                     }
5743                   else
5744                     constructor_pending_elts = r;
5745                 }
5746               else /* r->balance == -1 */
5747                 {
5748                   /* RL rotation */
5749                   struct init_node *t = r->left;
5750
5751                   r->left = t->right;
5752                   if (r->left)
5753                     r->left->parent = r;
5754                   t->right = r;
5755
5756                   p->right = t->left;
5757                   if (p->right)
5758                     p->right->parent = p;
5759                   t->left = p;
5760
5761                   r->balance = (t->balance < 0);
5762                   p->balance = -(t->balance > 0);
5763                   t->balance = 0;
5764
5765                   s = p->parent;
5766                   p->parent = t;
5767                   r->parent = t;
5768                   t->parent = s;
5769                   if (s)
5770                     {
5771                       if (s->left == p)
5772                         s->left = t;
5773                       else
5774                         s->right = t;
5775                     }
5776                   else
5777                     constructor_pending_elts = t;
5778                 }
5779               break;
5780             }
5781           else
5782             {
5783               /* p->balance == -1; growth of right side balances the node.  */
5784               p->balance = 0;
5785               break;
5786             }
5787         }
5788
5789       r = p;
5790       p = p->parent;
5791     }
5792 }
5793
5794 /* Build AVL tree from a sorted chain.  */
5795
5796 static void
5797 set_nonincremental_init (void)
5798 {
5799   unsigned HOST_WIDE_INT ix;
5800   tree index, value;
5801
5802   if (TREE_CODE (constructor_type) != RECORD_TYPE
5803       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5804     return;
5805
5806   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5807     add_pending_init (index, value);
5808   constructor_elements = 0;
5809   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5810     {
5811       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5812       /* Skip any nameless bit fields at the beginning.  */
5813       while (constructor_unfilled_fields != 0
5814              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5815              && DECL_NAME (constructor_unfilled_fields) == 0)
5816         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5817
5818     }
5819   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5820     {
5821       if (TYPE_DOMAIN (constructor_type))
5822         constructor_unfilled_index
5823             = convert (bitsizetype,
5824                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5825       else
5826         constructor_unfilled_index = bitsize_zero_node;
5827     }
5828   constructor_incremental = 0;
5829 }
5830
5831 /* Build AVL tree from a string constant.  */
5832
5833 static void
5834 set_nonincremental_init_from_string (tree str)
5835 {
5836   tree value, purpose, type;
5837   HOST_WIDE_INT val[2];
5838   const char *p, *end;
5839   int byte, wchar_bytes, charwidth, bitpos;
5840
5841   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5842
5843   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5844       == TYPE_PRECISION (char_type_node))
5845     wchar_bytes = 1;
5846   else
5847     {
5848       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5849                   == TYPE_PRECISION (wchar_type_node));
5850       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5851     }
5852   charwidth = TYPE_PRECISION (char_type_node);
5853   type = TREE_TYPE (constructor_type);
5854   p = TREE_STRING_POINTER (str);
5855   end = p + TREE_STRING_LENGTH (str);
5856
5857   for (purpose = bitsize_zero_node;
5858        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5859        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5860     {
5861       if (wchar_bytes == 1)
5862         {
5863           val[1] = (unsigned char) *p++;
5864           val[0] = 0;
5865         }
5866       else
5867         {
5868           val[0] = 0;
5869           val[1] = 0;
5870           for (byte = 0; byte < wchar_bytes; byte++)
5871             {
5872               if (BYTES_BIG_ENDIAN)
5873                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5874               else
5875                 bitpos = byte * charwidth;
5876               val[bitpos < HOST_BITS_PER_WIDE_INT]
5877                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5878                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5879             }
5880         }
5881
5882       if (!TYPE_UNSIGNED (type))
5883         {
5884           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5885           if (bitpos < HOST_BITS_PER_WIDE_INT)
5886             {
5887               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5888                 {
5889                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5890                   val[0] = -1;
5891                 }
5892             }
5893           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5894             {
5895               if (val[1] < 0)
5896                 val[0] = -1;
5897             }
5898           else if (val[0] & (((HOST_WIDE_INT) 1)
5899                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5900             val[0] |= ((HOST_WIDE_INT) -1)
5901                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5902         }
5903
5904       value = build_int_cst_wide (type, val[1], val[0]);
5905       add_pending_init (purpose, value);
5906     }
5907
5908   constructor_incremental = 0;
5909 }
5910
5911 /* Return value of FIELD in pending initializer or zero if the field was
5912    not initialized yet.  */
5913
5914 static tree
5915 find_init_member (tree field)
5916 {
5917   struct init_node *p;
5918
5919   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5920     {
5921       if (constructor_incremental
5922           && tree_int_cst_lt (field, constructor_unfilled_index))
5923         set_nonincremental_init ();
5924
5925       p = constructor_pending_elts;
5926       while (p)
5927         {
5928           if (tree_int_cst_lt (field, p->purpose))
5929             p = p->left;
5930           else if (tree_int_cst_lt (p->purpose, field))
5931             p = p->right;
5932           else
5933             return p->value;
5934         }
5935     }
5936   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5937     {
5938       tree bitpos = bit_position (field);
5939
5940       if (constructor_incremental
5941           && (!constructor_unfilled_fields
5942               || tree_int_cst_lt (bitpos,
5943                                   bit_position (constructor_unfilled_fields))))
5944         set_nonincremental_init ();
5945
5946       p = constructor_pending_elts;
5947       while (p)
5948         {
5949           if (field == p->purpose)
5950             return p->value;
5951           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5952             p = p->left;
5953           else
5954             p = p->right;
5955         }
5956     }
5957   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5958     {
5959       if (!VEC_empty (constructor_elt, constructor_elements)
5960           && (VEC_last (constructor_elt, constructor_elements)->index
5961               == field))
5962         return VEC_last (constructor_elt, constructor_elements)->value;
5963     }
5964   return 0;
5965 }
5966
5967 /* "Output" the next constructor element.
5968    At top level, really output it to assembler code now.
5969    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5970    TYPE is the data type that the containing data type wants here.
5971    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5972    If VALUE is a string constant, STRICT_STRING is true if it is
5973    unparenthesized or we should not warn here for it being parenthesized.
5974    For other types of VALUE, STRICT_STRING is not used.
5975
5976    PENDING if non-nil means output pending elements that belong
5977    right after this element.  (PENDING is normally 1;
5978    it is 0 while outputting pending elements, to avoid recursion.)  */
5979
5980 static void
5981 output_init_element (tree value, bool strict_string, tree type, tree field,
5982                      int pending)
5983 {
5984   constructor_elt *celt;
5985
5986   if (type == error_mark_node || value == error_mark_node)
5987     {
5988       constructor_erroneous = 1;
5989       return;
5990     }
5991   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5992       && (TREE_CODE (value) == STRING_CST
5993           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5994       && !(TREE_CODE (value) == STRING_CST
5995            && TREE_CODE (type) == ARRAY_TYPE
5996            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5997       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5998                      TYPE_MAIN_VARIANT (type)))
5999     value = array_to_pointer_conversion (value);
6000
6001   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6002       && require_constant_value && !flag_isoc99 && pending)
6003     {
6004       /* As an extension, allow initializing objects with static storage
6005          duration with compound literals (which are then treated just as
6006          the brace enclosed list they contain).  */
6007       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6008       value = DECL_INITIAL (decl);
6009     }
6010
6011   if (value == error_mark_node)
6012     constructor_erroneous = 1;
6013   else if (!TREE_CONSTANT (value))
6014     constructor_constant = 0;
6015   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6016            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6017                 || TREE_CODE (constructor_type) == UNION_TYPE)
6018                && DECL_C_BIT_FIELD (field)
6019                && TREE_CODE (value) != INTEGER_CST))
6020     constructor_simple = 0;
6021
6022   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6023     {
6024       if (require_constant_value)
6025         {
6026           error_init ("initializer element is not constant");
6027           value = error_mark_node;
6028         }
6029       else if (require_constant_elements)
6030         pedwarn ("initializer element is not computable at load time");
6031     }
6032
6033   /* If this field is empty (and not at the end of structure),
6034      don't do anything other than checking the initializer.  */
6035   if (field
6036       && (TREE_TYPE (field) == error_mark_node
6037           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6038               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6039               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6040                   || TREE_CHAIN (field)))))
6041     return;
6042
6043   value = digest_init (type, value, strict_string, require_constant_value);
6044   if (value == error_mark_node)
6045     {
6046       constructor_erroneous = 1;
6047       return;
6048     }
6049
6050   /* If this element doesn't come next in sequence,
6051      put it on constructor_pending_elts.  */
6052   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6053       && (!constructor_incremental
6054           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6055     {
6056       if (constructor_incremental
6057           && tree_int_cst_lt (field, constructor_unfilled_index))
6058         set_nonincremental_init ();
6059
6060       add_pending_init (field, value);
6061       return;
6062     }
6063   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6064            && (!constructor_incremental
6065                || field != constructor_unfilled_fields))
6066     {
6067       /* We do this for records but not for unions.  In a union,
6068          no matter which field is specified, it can be initialized
6069          right away since it starts at the beginning of the union.  */
6070       if (constructor_incremental)
6071         {
6072           if (!constructor_unfilled_fields)
6073             set_nonincremental_init ();
6074           else
6075             {
6076               tree bitpos, unfillpos;
6077
6078               bitpos = bit_position (field);
6079               unfillpos = bit_position (constructor_unfilled_fields);
6080
6081               if (tree_int_cst_lt (bitpos, unfillpos))
6082                 set_nonincremental_init ();
6083             }
6084         }
6085
6086       add_pending_init (field, value);
6087       return;
6088     }
6089   else if (TREE_CODE (constructor_type) == UNION_TYPE
6090            && !VEC_empty (constructor_elt, constructor_elements))
6091     {
6092       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6093                                        constructor_elements)->value))
6094         warning_init ("initialized field with side-effects overwritten");
6095
6096       /* We can have just one union field set.  */
6097       constructor_elements = 0;
6098     }
6099
6100   /* Otherwise, output this element either to
6101      constructor_elements or to the assembler file.  */
6102
6103   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6104   celt->index = field;
6105   celt->value = value;
6106
6107   /* Advance the variable that indicates sequential elements output.  */
6108   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6109     constructor_unfilled_index
6110       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6111                     bitsize_one_node);
6112   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6113     {
6114       constructor_unfilled_fields
6115         = TREE_CHAIN (constructor_unfilled_fields);
6116
6117       /* Skip any nameless bit fields.  */
6118       while (constructor_unfilled_fields != 0
6119              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6120              && DECL_NAME (constructor_unfilled_fields) == 0)
6121         constructor_unfilled_fields =
6122           TREE_CHAIN (constructor_unfilled_fields);
6123     }
6124   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6125     constructor_unfilled_fields = 0;
6126
6127   /* Now output any pending elements which have become next.  */
6128   if (pending)
6129     output_pending_init_elements (0);
6130 }
6131
6132 /* Output any pending elements which have become next.
6133    As we output elements, constructor_unfilled_{fields,index}
6134    advances, which may cause other elements to become next;
6135    if so, they too are output.
6136
6137    If ALL is 0, we return when there are
6138    no more pending elements to output now.
6139
6140    If ALL is 1, we output space as necessary so that
6141    we can output all the pending elements.  */
6142
6143 static void
6144 output_pending_init_elements (int all)
6145 {
6146   struct init_node *elt = constructor_pending_elts;
6147   tree next;
6148
6149  retry:
6150
6151   /* Look through the whole pending tree.
6152      If we find an element that should be output now,
6153      output it.  Otherwise, set NEXT to the element
6154      that comes first among those still pending.  */
6155
6156   next = 0;
6157   while (elt)
6158     {
6159       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6160         {
6161           if (tree_int_cst_equal (elt->purpose,
6162                                   constructor_unfilled_index))
6163             output_init_element (elt->value, true,
6164                                  TREE_TYPE (constructor_type),
6165                                  constructor_unfilled_index, 0);
6166           else if (tree_int_cst_lt (constructor_unfilled_index,
6167                                     elt->purpose))
6168             {
6169               /* Advance to the next smaller node.  */
6170               if (elt->left)
6171                 elt = elt->left;
6172               else
6173                 {
6174                   /* We have reached the smallest node bigger than the
6175                      current unfilled index.  Fill the space first.  */
6176                   next = elt->purpose;
6177                   break;
6178                 }
6179             }
6180           else
6181             {
6182               /* Advance to the next bigger node.  */
6183               if (elt->right)
6184                 elt = elt->right;
6185               else
6186                 {
6187                   /* We have reached the biggest node in a subtree.  Find
6188                      the parent of it, which is the next bigger node.  */
6189                   while (elt->parent && elt->parent->right == elt)
6190                     elt = elt->parent;
6191                   elt = elt->parent;
6192                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6193                                               elt->purpose))
6194                     {
6195                       next = elt->purpose;
6196                       break;
6197                     }
6198                 }
6199             }
6200         }
6201       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6202                || TREE_CODE (constructor_type) == UNION_TYPE)
6203         {
6204           tree ctor_unfilled_bitpos, elt_bitpos;
6205
6206           /* If the current record is complete we are done.  */
6207           if (constructor_unfilled_fields == 0)
6208             break;
6209
6210           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6211           elt_bitpos = bit_position (elt->purpose);
6212           /* We can't compare fields here because there might be empty
6213              fields in between.  */
6214           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6215             {
6216               constructor_unfilled_fields = elt->purpose;
6217               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6218                                    elt->purpose, 0);
6219             }
6220           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6221             {
6222               /* Advance to the next smaller node.  */
6223               if (elt->left)
6224                 elt = elt->left;
6225               else
6226                 {
6227                   /* We have reached the smallest node bigger than the
6228                      current unfilled field.  Fill the space first.  */
6229                   next = elt->purpose;
6230                   break;
6231                 }
6232             }
6233           else
6234             {
6235               /* Advance to the next bigger node.  */
6236               if (elt->right)
6237                 elt = elt->right;
6238               else
6239                 {
6240                   /* We have reached the biggest node in a subtree.  Find
6241                      the parent of it, which is the next bigger node.  */
6242                   while (elt->parent && elt->parent->right == elt)
6243                     elt = elt->parent;
6244                   elt = elt->parent;
6245                   if (elt
6246                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6247                                            bit_position (elt->purpose))))
6248                     {
6249                       next = elt->purpose;
6250                       break;
6251                     }
6252                 }
6253             }
6254         }
6255     }
6256
6257   /* Ordinarily return, but not if we want to output all
6258      and there are elements left.  */
6259   if (!(all && next != 0))
6260     return;
6261
6262   /* If it's not incremental, just skip over the gap, so that after
6263      jumping to retry we will output the next successive element.  */
6264   if (TREE_CODE (constructor_type) == RECORD_TYPE
6265       || TREE_CODE (constructor_type) == UNION_TYPE)
6266     constructor_unfilled_fields = next;
6267   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6268     constructor_unfilled_index = next;
6269
6270   /* ELT now points to the node in the pending tree with the next
6271      initializer to output.  */
6272   goto retry;
6273 }
6274 \f
6275 /* Add one non-braced element to the current constructor level.
6276    This adjusts the current position within the constructor's type.
6277    This may also start or terminate implicit levels
6278    to handle a partly-braced initializer.
6279
6280    Once this has found the correct level for the new element,
6281    it calls output_init_element.  */
6282
6283 void
6284 process_init_element (struct c_expr value)
6285 {
6286   tree orig_value = value.value;
6287   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6288   bool strict_string = value.original_code == STRING_CST;
6289
6290   designator_depth = 0;
6291   designator_erroneous = 0;
6292
6293   /* Handle superfluous braces around string cst as in
6294      char x[] = {"foo"}; */
6295   if (string_flag
6296       && constructor_type
6297       && TREE_CODE (constructor_type) == ARRAY_TYPE
6298       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6299       && integer_zerop (constructor_unfilled_index))
6300     {
6301       if (constructor_stack->replacement_value.value)
6302         error_init ("excess elements in char array initializer");
6303       constructor_stack->replacement_value = value;
6304       return;
6305     }
6306
6307   if (constructor_stack->replacement_value.value != 0)
6308     {
6309       error_init ("excess elements in struct initializer");
6310       return;
6311     }
6312
6313   /* Ignore elements of a brace group if it is entirely superfluous
6314      and has already been diagnosed.  */
6315   if (constructor_type == 0)
6316     return;
6317
6318   /* If we've exhausted any levels that didn't have braces,
6319      pop them now.  */
6320   while (constructor_stack->implicit)
6321     {
6322       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6323            || TREE_CODE (constructor_type) == UNION_TYPE)
6324           && constructor_fields == 0)
6325         process_init_element (pop_init_level (1));
6326       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6327                && (constructor_max_index == 0
6328                    || tree_int_cst_lt (constructor_max_index,
6329                                        constructor_index)))
6330         process_init_element (pop_init_level (1));
6331       else
6332         break;
6333     }
6334
6335   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6336   if (constructor_range_stack)
6337     {
6338       /* If value is a compound literal and we'll be just using its
6339          content, don't put it into a SAVE_EXPR.  */
6340       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6341           || !require_constant_value
6342           || flag_isoc99)
6343         value.value = save_expr (value.value);
6344     }
6345
6346   while (1)
6347     {
6348       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6349         {
6350           tree fieldtype;
6351           enum tree_code fieldcode;
6352
6353           if (constructor_fields == 0)
6354             {
6355               pedwarn_init ("excess elements in struct initializer");
6356               break;
6357             }
6358
6359           fieldtype = TREE_TYPE (constructor_fields);
6360           if (fieldtype != error_mark_node)
6361             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6362           fieldcode = TREE_CODE (fieldtype);
6363
6364           /* Error for non-static initialization of a flexible array member.  */
6365           if (fieldcode == ARRAY_TYPE
6366               && !require_constant_value
6367               && TYPE_SIZE (fieldtype) == NULL_TREE
6368               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6369             {
6370               error_init ("non-static initialization of a flexible array member");
6371               break;
6372             }
6373
6374           /* Accept a string constant to initialize a subarray.  */
6375           if (value.value != 0
6376               && fieldcode == ARRAY_TYPE
6377               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6378               && string_flag)
6379             value.value = orig_value;
6380           /* Otherwise, if we have come to a subaggregate,
6381              and we don't have an element of its type, push into it.  */
6382           else if (value.value != 0
6383                    && value.value != error_mark_node
6384                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6385                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6386                        || fieldcode == UNION_TYPE))
6387             {
6388               push_init_level (1);
6389               continue;
6390             }
6391
6392           if (value.value)
6393             {
6394               push_member_name (constructor_fields);
6395               output_init_element (value.value, strict_string,
6396                                    fieldtype, constructor_fields, 1);
6397               RESTORE_SPELLING_DEPTH (constructor_depth);
6398             }
6399           else
6400             /* Do the bookkeeping for an element that was
6401                directly output as a constructor.  */
6402             {
6403               /* For a record, keep track of end position of last field.  */
6404               if (DECL_SIZE (constructor_fields))
6405                 constructor_bit_index
6406                   = size_binop (PLUS_EXPR,
6407                                 bit_position (constructor_fields),
6408                                 DECL_SIZE (constructor_fields));
6409
6410               /* If the current field was the first one not yet written out,
6411                  it isn't now, so update.  */
6412               if (constructor_unfilled_fields == constructor_fields)
6413                 {
6414                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6415                   /* Skip any nameless bit fields.  */
6416                   while (constructor_unfilled_fields != 0
6417                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6418                          && DECL_NAME (constructor_unfilled_fields) == 0)
6419                     constructor_unfilled_fields =
6420                       TREE_CHAIN (constructor_unfilled_fields);
6421                 }
6422             }
6423
6424           constructor_fields = TREE_CHAIN (constructor_fields);
6425           /* Skip any nameless bit fields at the beginning.  */
6426           while (constructor_fields != 0
6427                  && DECL_C_BIT_FIELD (constructor_fields)
6428                  && DECL_NAME (constructor_fields) == 0)
6429             constructor_fields = TREE_CHAIN (constructor_fields);
6430         }
6431       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6432         {
6433           tree fieldtype;
6434           enum tree_code fieldcode;
6435
6436           if (constructor_fields == 0)
6437             {
6438               pedwarn_init ("excess elements in union initializer");
6439               break;
6440             }
6441
6442           fieldtype = TREE_TYPE (constructor_fields);
6443           if (fieldtype != error_mark_node)
6444             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6445           fieldcode = TREE_CODE (fieldtype);
6446
6447           /* Warn that traditional C rejects initialization of unions.
6448              We skip the warning if the value is zero.  This is done
6449              under the assumption that the zero initializer in user
6450              code appears conditioned on e.g. __STDC__ to avoid
6451              "missing initializer" warnings and relies on default
6452              initialization to zero in the traditional C case.
6453              We also skip the warning if the initializer is designated,
6454              again on the assumption that this must be conditional on
6455              __STDC__ anyway (and we've already complained about the
6456              member-designator already).  */
6457           if (!in_system_header && !constructor_designated
6458               && !(value.value && (integer_zerop (value.value)
6459                                    || real_zerop (value.value))))
6460             warning (OPT_Wtraditional, "traditional C rejects initialization "
6461                      "of unions");
6462
6463           /* Accept a string constant to initialize a subarray.  */
6464           if (value.value != 0
6465               && fieldcode == ARRAY_TYPE
6466               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6467               && string_flag)
6468             value.value = orig_value;
6469           /* Otherwise, if we have come to a subaggregate,
6470              and we don't have an element of its type, push into it.  */
6471           else if (value.value != 0
6472                    && value.value != error_mark_node
6473                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6474                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6475                        || fieldcode == UNION_TYPE))
6476             {
6477               push_init_level (1);
6478               continue;
6479             }
6480
6481           if (value.value)
6482             {
6483               push_member_name (constructor_fields);
6484               output_init_element (value.value, strict_string,
6485                                    fieldtype, constructor_fields, 1);
6486               RESTORE_SPELLING_DEPTH (constructor_depth);
6487             }
6488           else
6489             /* Do the bookkeeping for an element that was
6490                directly output as a constructor.  */
6491             {
6492               constructor_bit_index = DECL_SIZE (constructor_fields);
6493               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6494             }
6495
6496           constructor_fields = 0;
6497         }
6498       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6499         {
6500           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6501           enum tree_code eltcode = TREE_CODE (elttype);
6502
6503           /* Accept a string constant to initialize a subarray.  */
6504           if (value.value != 0
6505               && eltcode == ARRAY_TYPE
6506               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6507               && string_flag)
6508             value.value = orig_value;
6509           /* Otherwise, if we have come to a subaggregate,
6510              and we don't have an element of its type, push into it.  */
6511           else if (value.value != 0
6512                    && value.value != error_mark_node
6513                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6514                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6515                        || eltcode == UNION_TYPE))
6516             {
6517               push_init_level (1);
6518               continue;
6519             }
6520
6521           if (constructor_max_index != 0
6522               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6523                   || integer_all_onesp (constructor_max_index)))
6524             {
6525               pedwarn_init ("excess elements in array initializer");
6526               break;
6527             }
6528
6529           /* Now output the actual element.  */
6530           if (value.value)
6531             {
6532               push_array_bounds (tree_low_cst (constructor_index, 0));
6533               output_init_element (value.value, strict_string,
6534                                    elttype, constructor_index, 1);
6535               RESTORE_SPELLING_DEPTH (constructor_depth);
6536             }
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       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6548         {
6549           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6550
6551          /* Do a basic check of initializer size.  Note that vectors
6552             always have a fixed size derived from their type.  */
6553           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6554             {
6555               pedwarn_init ("excess elements in vector initializer");
6556               break;
6557             }
6558
6559           /* Now output the actual element.  */
6560           if (value.value)
6561             output_init_element (value.value, strict_string,
6562                                  elttype, constructor_index, 1);
6563
6564           constructor_index
6565             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6566
6567           if (!value.value)
6568             /* If we are doing the bookkeeping for an element that was
6569                directly output as a constructor, we must update
6570                constructor_unfilled_index.  */
6571             constructor_unfilled_index = constructor_index;
6572         }
6573
6574       /* Handle the sole element allowed in a braced initializer
6575          for a scalar variable.  */
6576       else if (constructor_type != error_mark_node
6577                && constructor_fields == 0)
6578         {
6579           pedwarn_init ("excess elements in scalar initializer");
6580           break;
6581         }
6582       else
6583         {
6584           if (value.value)
6585             output_init_element (value.value, strict_string,
6586                                  constructor_type, NULL_TREE, 1);
6587           constructor_fields = 0;
6588         }
6589
6590       /* Handle range initializers either at this level or anywhere higher
6591          in the designator stack.  */
6592       if (constructor_range_stack)
6593         {
6594           struct constructor_range_stack *p, *range_stack;
6595           int finish = 0;
6596
6597           range_stack = constructor_range_stack;
6598           constructor_range_stack = 0;
6599           while (constructor_stack != range_stack->stack)
6600             {
6601               gcc_assert (constructor_stack->implicit);
6602               process_init_element (pop_init_level (1));
6603             }
6604           for (p = range_stack;
6605                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6606                p = p->prev)
6607             {
6608               gcc_assert (constructor_stack->implicit);
6609               process_init_element (pop_init_level (1));
6610             }
6611
6612           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6613           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6614             finish = 1;
6615
6616           while (1)
6617             {
6618               constructor_index = p->index;
6619               constructor_fields = p->fields;
6620               if (finish && p->range_end && p->index == p->range_start)
6621                 {
6622                   finish = 0;
6623                   p->prev = 0;
6624                 }
6625               p = p->next;
6626               if (!p)
6627                 break;
6628               push_init_level (2);
6629               p->stack = constructor_stack;
6630               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6631                 p->index = p->range_start;
6632             }
6633
6634           if (!finish)
6635             constructor_range_stack = range_stack;
6636           continue;
6637         }
6638
6639       break;
6640     }
6641
6642   constructor_range_stack = 0;
6643 }
6644 \f
6645 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6646    (guaranteed to be 'volatile' or null) and ARGS (represented using
6647    an ASM_EXPR node).  */
6648 tree
6649 build_asm_stmt (tree cv_qualifier, tree args)
6650 {
6651   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6652     ASM_VOLATILE_P (args) = 1;
6653   return add_stmt (args);
6654 }
6655
6656 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6657    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6658    SIMPLE indicates whether there was anything at all after the
6659    string in the asm expression -- asm("blah") and asm("blah" : )
6660    are subtly different.  We use a ASM_EXPR node to represent this.  */
6661 tree
6662 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6663                 bool simple)
6664 {
6665   tree tail;
6666   tree args;
6667   int i;
6668   const char *constraint;
6669   const char **oconstraints;
6670   bool allows_mem, allows_reg, is_inout;
6671   int ninputs, noutputs;
6672
6673   ninputs = list_length (inputs);
6674   noutputs = list_length (outputs);
6675   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6676
6677   string = resolve_asm_operand_names (string, outputs, inputs);
6678
6679   /* Remove output conversions that change the type but not the mode.  */
6680   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6681     {
6682       tree output = TREE_VALUE (tail);
6683
6684       /* ??? Really, this should not be here.  Users should be using a
6685          proper lvalue, dammit.  But there's a long history of using casts
6686          in the output operands.  In cases like longlong.h, this becomes a
6687          primitive form of typechecking -- if the cast can be removed, then
6688          the output operand had a type of the proper width; otherwise we'll
6689          get an error.  Gross, but ...  */
6690       STRIP_NOPS (output);
6691
6692       if (!lvalue_or_else (output, lv_asm))
6693         output = error_mark_node;
6694
6695       if (output != error_mark_node
6696           && (TREE_READONLY (output)
6697               || TYPE_READONLY (TREE_TYPE (output))
6698               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6699                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6700                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6701         readonly_error (output, lv_asm);
6702
6703       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6704       oconstraints[i] = constraint;
6705
6706       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6707                                    &allows_mem, &allows_reg, &is_inout))
6708         {
6709           /* If the operand is going to end up in memory,
6710              mark it addressable.  */
6711           if (!allows_reg && !c_mark_addressable (output))
6712             output = error_mark_node;
6713         }
6714       else
6715         output = error_mark_node;
6716
6717       TREE_VALUE (tail) = output;
6718     }
6719
6720   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6721     {
6722       tree input;
6723
6724       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6725       input = TREE_VALUE (tail);
6726
6727       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6728                                   oconstraints, &allows_mem, &allows_reg))
6729         {
6730           /* If the operand is going to end up in memory,
6731              mark it addressable.  */
6732           if (!allows_reg && allows_mem)
6733             {
6734               /* Strip the nops as we allow this case.  FIXME, this really
6735                  should be rejected or made deprecated.  */
6736               STRIP_NOPS (input);
6737               if (!c_mark_addressable (input))
6738                 input = error_mark_node;
6739           }
6740         }
6741       else
6742         input = error_mark_node;
6743
6744       TREE_VALUE (tail) = input;
6745     }
6746
6747   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6748
6749   /* asm statements without outputs, including simple ones, are treated
6750      as volatile.  */
6751   ASM_INPUT_P (args) = simple;
6752   ASM_VOLATILE_P (args) = (noutputs == 0);
6753
6754   return args;
6755 }
6756 \f
6757 /* Generate a goto statement to LABEL.  */
6758
6759 tree
6760 c_finish_goto_label (tree label)
6761 {
6762   tree decl = lookup_label (label);
6763   if (!decl)
6764     return NULL_TREE;
6765
6766   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6767     {
6768       error ("jump into statement expression");
6769       return NULL_TREE;
6770     }
6771
6772   if (C_DECL_UNJUMPABLE_VM (decl))
6773     {
6774       error ("jump into scope of identifier with variably modified type");
6775       return NULL_TREE;
6776     }
6777
6778   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6779     {
6780       /* No jump from outside this statement expression context, so
6781          record that there is a jump from within this context.  */
6782       struct c_label_list *nlist;
6783       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6784       nlist->next = label_context_stack_se->labels_used;
6785       nlist->label = decl;
6786       label_context_stack_se->labels_used = nlist;
6787     }
6788
6789   if (!C_DECL_UNDEFINABLE_VM (decl))
6790     {
6791       /* No jump from outside this context context of identifiers with
6792          variably modified type, so record that there is a jump from
6793          within this context.  */
6794       struct c_label_list *nlist;
6795       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6796       nlist->next = label_context_stack_vm->labels_used;
6797       nlist->label = decl;
6798       label_context_stack_vm->labels_used = nlist;
6799     }
6800
6801   TREE_USED (decl) = 1;
6802   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6803 }
6804
6805 /* Generate a computed goto statement to EXPR.  */
6806
6807 tree
6808 c_finish_goto_ptr (tree expr)
6809 {
6810   if (pedantic)
6811     pedwarn ("ISO C forbids %<goto *expr;%>");
6812   expr = convert (ptr_type_node, expr);
6813   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6814 }
6815
6816 /* Generate a C `return' statement.  RETVAL is the expression for what
6817    to return, or a null pointer for `return;' with no value.  */
6818
6819 tree
6820 c_finish_return (tree retval)
6821 {
6822   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6823   bool no_warning = false;
6824
6825   if (TREE_THIS_VOLATILE (current_function_decl))
6826     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6827
6828   if (!retval)
6829     {
6830       current_function_returns_null = 1;
6831       if ((warn_return_type || flag_isoc99)
6832           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6833         {
6834           pedwarn_c99 ("%<return%> with no value, in "
6835                        "function returning non-void");
6836           no_warning = true;
6837         }
6838     }
6839   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6840     {
6841       current_function_returns_null = 1;
6842       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6843         pedwarn ("%<return%> with a value, in function returning void");
6844     }
6845   else
6846     {
6847       tree t = convert_for_assignment (valtype, retval, ic_return,
6848                                        NULL_TREE, NULL_TREE, 0);
6849       tree res = DECL_RESULT (current_function_decl);
6850       tree inner;
6851
6852       current_function_returns_value = 1;
6853       if (t == error_mark_node)
6854         return NULL_TREE;
6855
6856       inner = t = convert (TREE_TYPE (res), t);
6857
6858       /* Strip any conversions, additions, and subtractions, and see if
6859          we are returning the address of a local variable.  Warn if so.  */
6860       while (1)
6861         {
6862           switch (TREE_CODE (inner))
6863             {
6864             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6865             case PLUS_EXPR:
6866               inner = TREE_OPERAND (inner, 0);
6867               continue;
6868
6869             case MINUS_EXPR:
6870               /* If the second operand of the MINUS_EXPR has a pointer
6871                  type (or is converted from it), this may be valid, so
6872                  don't give a warning.  */
6873               {
6874                 tree op1 = TREE_OPERAND (inner, 1);
6875
6876                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6877                        && (TREE_CODE (op1) == NOP_EXPR
6878                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6879                            || TREE_CODE (op1) == CONVERT_EXPR))
6880                   op1 = TREE_OPERAND (op1, 0);
6881
6882                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6883                   break;
6884
6885                 inner = TREE_OPERAND (inner, 0);
6886                 continue;
6887               }
6888
6889             case ADDR_EXPR:
6890               inner = TREE_OPERAND (inner, 0);
6891
6892               while (REFERENCE_CLASS_P (inner)
6893                      && TREE_CODE (inner) != INDIRECT_REF)
6894                 inner = TREE_OPERAND (inner, 0);
6895
6896               if (DECL_P (inner)
6897                   && !DECL_EXTERNAL (inner)
6898                   && !TREE_STATIC (inner)
6899                   && DECL_CONTEXT (inner) == current_function_decl)
6900                 warning (0, "function returns address of local variable");
6901               break;
6902
6903             default:
6904               break;
6905             }
6906
6907           break;
6908         }
6909
6910       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6911     }
6912
6913   ret_stmt = build_stmt (RETURN_EXPR, retval);
6914   TREE_NO_WARNING (ret_stmt) |= no_warning;
6915   return add_stmt (ret_stmt);
6916 }
6917 \f
6918 struct c_switch {
6919   /* The SWITCH_EXPR being built.  */
6920   tree switch_expr;
6921
6922   /* The original type of the testing expression, i.e. before the
6923      default conversion is applied.  */
6924   tree orig_type;
6925
6926   /* A splay-tree mapping the low element of a case range to the high
6927      element, or NULL_TREE if there is no high element.  Used to
6928      determine whether or not a new case label duplicates an old case
6929      label.  We need a tree, rather than simply a hash table, because
6930      of the GNU case range extension.  */
6931   splay_tree cases;
6932
6933   /* Number of nested statement expressions within this switch
6934      statement; if nonzero, case and default labels may not
6935      appear.  */
6936   unsigned int blocked_stmt_expr;
6937
6938   /* Scope of outermost declarations of identifiers with variably
6939      modified type within this switch statement; if nonzero, case and
6940      default labels may not appear.  */
6941   unsigned int blocked_vm;
6942
6943   /* The next node on the stack.  */
6944   struct c_switch *next;
6945 };
6946
6947 /* A stack of the currently active switch statements.  The innermost
6948    switch statement is on the top of the stack.  There is no need to
6949    mark the stack for garbage collection because it is only active
6950    during the processing of the body of a function, and we never
6951    collect at that point.  */
6952
6953 struct c_switch *c_switch_stack;
6954
6955 /* Start a C switch statement, testing expression EXP.  Return the new
6956    SWITCH_EXPR.  */
6957
6958 tree
6959 c_start_case (tree exp)
6960 {
6961   enum tree_code code;
6962   tree type, orig_type = error_mark_node;
6963   struct c_switch *cs;
6964
6965   if (exp != error_mark_node)
6966     {
6967       code = TREE_CODE (TREE_TYPE (exp));
6968       orig_type = TREE_TYPE (exp);
6969
6970       if (!INTEGRAL_TYPE_P (orig_type)
6971           && code != ERROR_MARK)
6972         {
6973           error ("switch quantity not an integer");
6974           exp = integer_zero_node;
6975           orig_type = error_mark_node;
6976         }
6977       else
6978         {
6979           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6980
6981           if (!in_system_header
6982               && (type == long_integer_type_node
6983                   || type == long_unsigned_type_node))
6984             warning (OPT_Wtraditional, "%<long%> switch expression not "
6985                      "converted to %<int%> in ISO C");
6986
6987           exp = default_conversion (exp);
6988           type = TREE_TYPE (exp);
6989         }
6990     }
6991
6992   /* Add this new SWITCH_EXPR to the stack.  */
6993   cs = XNEW (struct c_switch);
6994   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6995   cs->orig_type = orig_type;
6996   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6997   cs->blocked_stmt_expr = 0;
6998   cs->blocked_vm = 0;
6999   cs->next = c_switch_stack;
7000   c_switch_stack = cs;
7001
7002   return add_stmt (cs->switch_expr);
7003 }
7004
7005 /* Process a case label.  */
7006
7007 tree
7008 do_case (tree low_value, tree high_value)
7009 {
7010   tree label = NULL_TREE;
7011
7012   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7013       && !c_switch_stack->blocked_vm)
7014     {
7015       label = c_add_case_label (c_switch_stack->cases,
7016                                 SWITCH_COND (c_switch_stack->switch_expr),
7017                                 c_switch_stack->orig_type,
7018                                 low_value, high_value);
7019       if (label == error_mark_node)
7020         label = NULL_TREE;
7021     }
7022   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7023     {
7024       if (low_value)
7025         error ("case label in statement expression not containing "
7026                "enclosing switch statement");
7027       else
7028         error ("%<default%> label in statement expression not containing "
7029                "enclosing switch statement");
7030     }
7031   else if (c_switch_stack && c_switch_stack->blocked_vm)
7032     {
7033       if (low_value)
7034         error ("case label in scope of identifier with variably modified "
7035                "type not containing enclosing switch statement");
7036       else
7037         error ("%<default%> label in scope of identifier with variably "
7038                "modified type not containing enclosing switch statement");
7039     }
7040   else if (low_value)
7041     error ("case label not within a switch statement");
7042   else
7043     error ("%<default%> label not within a switch statement");
7044
7045   return label;
7046 }
7047
7048 /* Finish the switch statement.  */
7049
7050 void
7051 c_finish_case (tree body)
7052 {
7053   struct c_switch *cs = c_switch_stack;
7054   location_t switch_location;
7055
7056   SWITCH_BODY (cs->switch_expr) = body;
7057
7058   /* We must not be within a statement expression nested in the switch
7059      at this point; we might, however, be within the scope of an
7060      identifier with variably modified type nested in the switch.  */
7061   gcc_assert (!cs->blocked_stmt_expr);
7062
7063   /* Emit warnings as needed.  */
7064   if (EXPR_HAS_LOCATION (cs->switch_expr))
7065     switch_location = EXPR_LOCATION (cs->switch_expr);
7066   else
7067     switch_location = input_location;
7068   c_do_switch_warnings (cs->cases, switch_location,
7069                         TREE_TYPE (cs->switch_expr),
7070                         SWITCH_COND (cs->switch_expr));
7071
7072   /* Pop the stack.  */
7073   c_switch_stack = cs->next;
7074   splay_tree_delete (cs->cases);
7075   XDELETE (cs);
7076 }
7077 \f
7078 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7079    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7080    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7081    statement, and was not surrounded with parenthesis.  */
7082
7083 void
7084 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7085                   tree else_block, bool nested_if)
7086 {
7087   tree stmt;
7088
7089   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7090   if (warn_parentheses && nested_if && else_block == NULL)
7091     {
7092       tree inner_if = then_block;
7093
7094       /* We know from the grammar productions that there is an IF nested
7095          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7096          it might not be exactly THEN_BLOCK, but should be the last
7097          non-container statement within.  */
7098       while (1)
7099         switch (TREE_CODE (inner_if))
7100           {
7101           case COND_EXPR:
7102             goto found;
7103           case BIND_EXPR:
7104             inner_if = BIND_EXPR_BODY (inner_if);
7105             break;
7106           case STATEMENT_LIST:
7107             inner_if = expr_last (then_block);
7108             break;
7109           case TRY_FINALLY_EXPR:
7110           case TRY_CATCH_EXPR:
7111             inner_if = TREE_OPERAND (inner_if, 0);
7112             break;
7113           default:
7114             gcc_unreachable ();
7115           }
7116     found:
7117
7118       if (COND_EXPR_ELSE (inner_if))
7119          warning (OPT_Wparentheses,
7120                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7121                   &if_locus);
7122     }
7123
7124   /* Diagnose ";" via the special empty statement node that we create.  */
7125   if (extra_warnings)
7126     {
7127       tree *inner_then = &then_block, *inner_else = &else_block;
7128
7129       if (TREE_CODE (*inner_then) == STATEMENT_LIST
7130           && STATEMENT_LIST_TAIL (*inner_then))
7131         inner_then = &STATEMENT_LIST_TAIL (*inner_then)->stmt;
7132       if (*inner_else && TREE_CODE (*inner_else) == STATEMENT_LIST
7133           && STATEMENT_LIST_TAIL (*inner_else))
7134         inner_else = &STATEMENT_LIST_TAIL (*inner_else)->stmt;
7135
7136       if (TREE_CODE (*inner_then) == NOP_EXPR && !TREE_TYPE (*inner_then))
7137         {
7138           if (!*inner_else)
7139             warning (0, "%Hempty body in an if-statement",
7140                      EXPR_LOCUS (*inner_then));
7141
7142           *inner_then = alloc_stmt_list ();
7143         }
7144       if (*inner_else
7145           && TREE_CODE (*inner_else) == NOP_EXPR
7146           && !TREE_TYPE (*inner_else))
7147         {
7148           warning (0, "%Hempty body in an else-statement",
7149                    EXPR_LOCUS (*inner_else));
7150
7151           *inner_else = alloc_stmt_list ();
7152         }
7153     }
7154
7155   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7156   SET_EXPR_LOCATION (stmt, if_locus);
7157   add_stmt (stmt);
7158 }
7159
7160 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7161    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7162    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7163    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7164    the continue label.  Everything is allowed to be NULL.  */
7165
7166 void
7167 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7168                tree blab, tree clab, bool cond_is_first)
7169 {
7170   tree entry = NULL, exit = NULL, t;
7171
7172   /* If the condition is zero don't generate a loop construct.  */
7173   if (cond && integer_zerop (cond))
7174     {
7175       if (cond_is_first)
7176         {
7177           t = build_and_jump (&blab);
7178           SET_EXPR_LOCATION (t, start_locus);
7179           add_stmt (t);
7180         }
7181     }
7182   else
7183     {
7184       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7185
7186       /* If we have an exit condition, then we build an IF with gotos either
7187          out of the loop, or to the top of it.  If there's no exit condition,
7188          then we just build a jump back to the top.  */
7189       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7190
7191       if (cond && !integer_nonzerop (cond))
7192         {
7193           /* Canonicalize the loop condition to the end.  This means
7194              generating a branch to the loop condition.  Reuse the
7195              continue label, if possible.  */
7196           if (cond_is_first)
7197             {
7198               if (incr || !clab)
7199                 {
7200                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7201                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7202                 }
7203               else
7204                 t = build1 (GOTO_EXPR, void_type_node, clab);
7205               SET_EXPR_LOCATION (t, start_locus);
7206               add_stmt (t);
7207             }
7208
7209           t = build_and_jump (&blab);
7210           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7211           if (cond_is_first)
7212             SET_EXPR_LOCATION (exit, start_locus);
7213           else
7214             SET_EXPR_LOCATION (exit, input_location);
7215         }
7216
7217       add_stmt (top);
7218     }
7219
7220   if (body)
7221     add_stmt (body);
7222   if (clab)
7223     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7224   if (incr)
7225     add_stmt (incr);
7226   if (entry)
7227     add_stmt (entry);
7228   if (exit)
7229     add_stmt (exit);
7230   if (blab)
7231     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7232 }
7233
7234 tree
7235 c_finish_bc_stmt (tree *label_p, bool is_break)
7236 {
7237   bool skip;
7238   tree label = *label_p;
7239
7240   /* In switch statements break is sometimes stylistically used after
7241      a return statement.  This can lead to spurious warnings about
7242      control reaching the end of a non-void function when it is
7243      inlined.  Note that we are calling block_may_fallthru with
7244      language specific tree nodes; this works because
7245      block_may_fallthru returns true when given something it does not
7246      understand.  */
7247   skip = !block_may_fallthru (cur_stmt_list);
7248
7249   if (!label)
7250     {
7251       if (!skip)
7252         *label_p = label = create_artificial_label ();
7253     }
7254   else if (TREE_CODE (label) != LABEL_DECL)
7255     {
7256       if (is_break)
7257         error ("break statement not within loop or switch");
7258       else
7259         error ("continue statement not within a loop");
7260       return NULL_TREE;
7261     }
7262
7263   if (skip)
7264     return NULL_TREE;
7265
7266   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7267 }
7268
7269 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7270
7271 static void
7272 emit_side_effect_warnings (tree expr)
7273 {
7274   if (expr == error_mark_node)
7275     ;
7276   else if (!TREE_SIDE_EFFECTS (expr))
7277     {
7278       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7279         warning (0, "%Hstatement with no effect",
7280                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7281     }
7282   else if (warn_unused_value)
7283     warn_if_unused_value (expr, input_location);
7284 }
7285
7286 /* Process an expression as if it were a complete statement.  Emit
7287    diagnostics, but do not call ADD_STMT.  */
7288
7289 tree
7290 c_process_expr_stmt (tree expr)
7291 {
7292   if (!expr)
7293     return NULL_TREE;
7294
7295   if (warn_sequence_point)
7296     verify_sequence_points (expr);
7297
7298   if (TREE_TYPE (expr) != error_mark_node
7299       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7300       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7301     error ("expression statement has incomplete type");
7302
7303   /* If we're not processing a statement expression, warn about unused values.
7304      Warnings for statement expressions will be emitted later, once we figure
7305      out which is the result.  */
7306   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7307       && (extra_warnings || warn_unused_value))
7308     emit_side_effect_warnings (expr);
7309
7310   /* If the expression is not of a type to which we cannot assign a line
7311      number, wrap the thing in a no-op NOP_EXPR.  */
7312   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7313     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7314
7315   if (EXPR_P (expr))
7316     SET_EXPR_LOCATION (expr, input_location);
7317
7318   return expr;
7319 }
7320
7321 /* Emit an expression as a statement.  */
7322
7323 tree
7324 c_finish_expr_stmt (tree expr)
7325 {
7326   if (expr)
7327     return add_stmt (c_process_expr_stmt (expr));
7328   else
7329     return NULL;
7330 }
7331
7332 /* Do the opposite and emit a statement as an expression.  To begin,
7333    create a new binding level and return it.  */
7334
7335 tree
7336 c_begin_stmt_expr (void)
7337 {
7338   tree ret;
7339   struct c_label_context_se *nstack;
7340   struct c_label_list *glist;
7341
7342   /* We must force a BLOCK for this level so that, if it is not expanded
7343      later, there is a way to turn off the entire subtree of blocks that
7344      are contained in it.  */
7345   keep_next_level ();
7346   ret = c_begin_compound_stmt (true);
7347   if (c_switch_stack)
7348     {
7349       c_switch_stack->blocked_stmt_expr++;
7350       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7351     }
7352   for (glist = label_context_stack_se->labels_used;
7353        glist != NULL;
7354        glist = glist->next)
7355     {
7356       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7357     }
7358   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7359   nstack->labels_def = NULL;
7360   nstack->labels_used = NULL;
7361   nstack->next = label_context_stack_se;
7362   label_context_stack_se = nstack;
7363
7364   /* Mark the current statement list as belonging to a statement list.  */
7365   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7366
7367   return ret;
7368 }
7369
7370 tree
7371 c_finish_stmt_expr (tree body)
7372 {
7373   tree last, type, tmp, val;
7374   tree *last_p;
7375   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7376
7377   body = c_end_compound_stmt (body, true);
7378   if (c_switch_stack)
7379     {
7380       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7381       c_switch_stack->blocked_stmt_expr--;
7382     }
7383   /* It is no longer possible to jump to labels defined within this
7384      statement expression.  */
7385   for (dlist = label_context_stack_se->labels_def;
7386        dlist != NULL;
7387        dlist = dlist->next)
7388     {
7389       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7390     }
7391   /* It is again possible to define labels with a goto just outside
7392      this statement expression.  */
7393   for (glist = label_context_stack_se->next->labels_used;
7394        glist != NULL;
7395        glist = glist->next)
7396     {
7397       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7398       glist_prev = glist;
7399     }
7400   if (glist_prev != NULL)
7401     glist_prev->next = label_context_stack_se->labels_used;
7402   else
7403     label_context_stack_se->next->labels_used
7404       = label_context_stack_se->labels_used;
7405   label_context_stack_se = label_context_stack_se->next;
7406
7407   /* Locate the last statement in BODY.  See c_end_compound_stmt
7408      about always returning a BIND_EXPR.  */
7409   last_p = &BIND_EXPR_BODY (body);
7410   last = BIND_EXPR_BODY (body);
7411
7412  continue_searching:
7413   if (TREE_CODE (last) == STATEMENT_LIST)
7414     {
7415       tree_stmt_iterator i;
7416
7417       /* This can happen with degenerate cases like ({ }).  No value.  */
7418       if (!TREE_SIDE_EFFECTS (last))
7419         return body;
7420
7421       /* If we're supposed to generate side effects warnings, process
7422          all of the statements except the last.  */
7423       if (extra_warnings || warn_unused_value)
7424         {
7425           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7426             emit_side_effect_warnings (tsi_stmt (i));
7427         }
7428       else
7429         i = tsi_last (last);
7430       last_p = tsi_stmt_ptr (i);
7431       last = *last_p;
7432     }
7433
7434   /* If the end of the list is exception related, then the list was split
7435      by a call to push_cleanup.  Continue searching.  */
7436   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7437       || TREE_CODE (last) == TRY_CATCH_EXPR)
7438     {
7439       last_p = &TREE_OPERAND (last, 0);
7440       last = *last_p;
7441       goto continue_searching;
7442     }
7443
7444   /* In the case that the BIND_EXPR is not necessary, return the
7445      expression out from inside it.  */
7446   if (last == error_mark_node
7447       || (last == BIND_EXPR_BODY (body)
7448           && BIND_EXPR_VARS (body) == NULL))
7449     {
7450       /* Do not warn if the return value of a statement expression is
7451          unused.  */
7452       if (EXPR_P (last))
7453         TREE_NO_WARNING (last) = 1;
7454       return last;
7455     }
7456
7457   /* Extract the type of said expression.  */
7458   type = TREE_TYPE (last);
7459
7460   /* If we're not returning a value at all, then the BIND_EXPR that
7461      we already have is a fine expression to return.  */
7462   if (!type || VOID_TYPE_P (type))
7463     return body;
7464
7465   /* Now that we've located the expression containing the value, it seems
7466      silly to make voidify_wrapper_expr repeat the process.  Create a
7467      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7468   tmp = create_tmp_var_raw (type, NULL);
7469
7470   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7471      tree_expr_nonnegative_p giving up immediately.  */
7472   val = last;
7473   if (TREE_CODE (val) == NOP_EXPR
7474       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7475     val = TREE_OPERAND (val, 0);
7476
7477   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7478   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7479
7480   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7481 }
7482
7483 /* Begin the scope of an identifier of variably modified type, scope
7484    number SCOPE.  Jumping from outside this scope to inside it is not
7485    permitted.  */
7486
7487 void
7488 c_begin_vm_scope (unsigned int scope)
7489 {
7490   struct c_label_context_vm *nstack;
7491   struct c_label_list *glist;
7492
7493   gcc_assert (scope > 0);
7494   if (c_switch_stack && !c_switch_stack->blocked_vm)
7495     c_switch_stack->blocked_vm = scope;
7496   for (glist = label_context_stack_vm->labels_used;
7497        glist != NULL;
7498        glist = glist->next)
7499     {
7500       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7501     }
7502   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7503   nstack->labels_def = NULL;
7504   nstack->labels_used = NULL;
7505   nstack->scope = scope;
7506   nstack->next = label_context_stack_vm;
7507   label_context_stack_vm = nstack;
7508 }
7509
7510 /* End a scope which may contain identifiers of variably modified
7511    type, scope number SCOPE.  */
7512
7513 void
7514 c_end_vm_scope (unsigned int scope)
7515 {
7516   if (label_context_stack_vm == NULL)
7517     return;
7518   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7519     c_switch_stack->blocked_vm = 0;
7520   /* We may have a number of nested scopes of identifiers with
7521      variably modified type, all at this depth.  Pop each in turn.  */
7522   while (label_context_stack_vm->scope == scope)
7523     {
7524       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7525
7526       /* It is no longer possible to jump to labels defined within this
7527          scope.  */
7528       for (dlist = label_context_stack_vm->labels_def;
7529            dlist != NULL;
7530            dlist = dlist->next)
7531         {
7532           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7533         }
7534       /* It is again possible to define labels with a goto just outside
7535          this scope.  */
7536       for (glist = label_context_stack_vm->next->labels_used;
7537            glist != NULL;
7538            glist = glist->next)
7539         {
7540           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7541           glist_prev = glist;
7542         }
7543       if (glist_prev != NULL)
7544         glist_prev->next = label_context_stack_vm->labels_used;
7545       else
7546         label_context_stack_vm->next->labels_used
7547           = label_context_stack_vm->labels_used;
7548       label_context_stack_vm = label_context_stack_vm->next;
7549     }
7550 }
7551 \f
7552 /* Begin and end compound statements.  This is as simple as pushing
7553    and popping new statement lists from the tree.  */
7554
7555 tree
7556 c_begin_compound_stmt (bool do_scope)
7557 {
7558   tree stmt = push_stmt_list ();
7559   if (do_scope)
7560     push_scope ();
7561   return stmt;
7562 }
7563
7564 tree
7565 c_end_compound_stmt (tree stmt, bool do_scope)
7566 {
7567   tree block = NULL;
7568
7569   if (do_scope)
7570     {
7571       if (c_dialect_objc ())
7572         objc_clear_super_receiver ();
7573       block = pop_scope ();
7574     }
7575
7576   stmt = pop_stmt_list (stmt);
7577   stmt = c_build_bind_expr (block, stmt);
7578
7579   /* If this compound statement is nested immediately inside a statement
7580      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7581      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7582      STATEMENT_LISTs merge, and thus we can lose track of what statement
7583      was really last.  */
7584   if (cur_stmt_list
7585       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7586       && TREE_CODE (stmt) != BIND_EXPR)
7587     {
7588       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7589       TREE_SIDE_EFFECTS (stmt) = 1;
7590     }
7591
7592   return stmt;
7593 }
7594
7595 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7596    when the current scope is exited.  EH_ONLY is true when this is not
7597    meant to apply to normal control flow transfer.  */
7598
7599 void
7600 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7601 {
7602   enum tree_code code;
7603   tree stmt, list;
7604   bool stmt_expr;
7605
7606   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7607   stmt = build_stmt (code, NULL, cleanup);
7608   add_stmt (stmt);
7609   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7610   list = push_stmt_list ();
7611   TREE_OPERAND (stmt, 0) = list;
7612   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7613 }
7614 \f
7615 /* Build a binary-operation expression without default conversions.
7616    CODE is the kind of expression to build.
7617    This function differs from `build' in several ways:
7618    the data type of the result is computed and recorded in it,
7619    warnings are generated if arg data types are invalid,
7620    special handling for addition and subtraction of pointers is known,
7621    and some optimization is done (operations on narrow ints
7622    are done in the narrower type when that gives the same result).
7623    Constant folding is also done before the result is returned.
7624
7625    Note that the operands will never have enumeral types, or function
7626    or array types, because either they will have the default conversions
7627    performed or they have both just been converted to some other type in which
7628    the arithmetic is to be done.  */
7629
7630 tree
7631 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7632                  int convert_p)
7633 {
7634   tree type0, type1;
7635   enum tree_code code0, code1;
7636   tree op0, op1;
7637   const char *invalid_op_diag;
7638
7639   /* Expression code to give to the expression when it is built.
7640      Normally this is CODE, which is what the caller asked for,
7641      but in some special cases we change it.  */
7642   enum tree_code resultcode = code;
7643
7644   /* Data type in which the computation is to be performed.
7645      In the simplest cases this is the common type of the arguments.  */
7646   tree result_type = NULL;
7647
7648   /* Nonzero means operands have already been type-converted
7649      in whatever way is necessary.
7650      Zero means they need to be converted to RESULT_TYPE.  */
7651   int converted = 0;
7652
7653   /* Nonzero means create the expression with this type, rather than
7654      RESULT_TYPE.  */
7655   tree build_type = 0;
7656
7657   /* Nonzero means after finally constructing the expression
7658      convert it to this type.  */
7659   tree final_type = 0;
7660
7661   /* Nonzero if this is an operation like MIN or MAX which can
7662      safely be computed in short if both args are promoted shorts.
7663      Also implies COMMON.
7664      -1 indicates a bitwise operation; this makes a difference
7665      in the exact conditions for when it is safe to do the operation
7666      in a narrower mode.  */
7667   int shorten = 0;
7668
7669   /* Nonzero if this is a comparison operation;
7670      if both args are promoted shorts, compare the original shorts.
7671      Also implies COMMON.  */
7672   int short_compare = 0;
7673
7674   /* Nonzero if this is a right-shift operation, which can be computed on the
7675      original short and then promoted if the operand is a promoted short.  */
7676   int short_shift = 0;
7677
7678   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7679   int common = 0;
7680
7681   /* True means types are compatible as far as ObjC is concerned.  */
7682   bool objc_ok;
7683
7684   if (convert_p)
7685     {
7686       op0 = default_conversion (orig_op0);
7687       op1 = default_conversion (orig_op1);
7688     }
7689   else
7690     {
7691       op0 = orig_op0;
7692       op1 = orig_op1;
7693     }
7694
7695   type0 = TREE_TYPE (op0);
7696   type1 = TREE_TYPE (op1);
7697
7698   /* The expression codes of the data types of the arguments tell us
7699      whether the arguments are integers, floating, pointers, etc.  */
7700   code0 = TREE_CODE (type0);
7701   code1 = TREE_CODE (type1);
7702
7703   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7704   STRIP_TYPE_NOPS (op0);
7705   STRIP_TYPE_NOPS (op1);
7706
7707   /* If an error was already reported for one of the arguments,
7708      avoid reporting another error.  */
7709
7710   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7711     return error_mark_node;
7712
7713   if ((invalid_op_diag
7714        = targetm.invalid_binary_op (code, type0, type1)))
7715     {
7716       error (invalid_op_diag);
7717       return error_mark_node;
7718     }
7719
7720   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7721
7722   switch (code)
7723     {
7724     case PLUS_EXPR:
7725       /* Handle the pointer + int case.  */
7726       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7727         return pointer_int_sum (PLUS_EXPR, op0, op1);
7728       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7729         return pointer_int_sum (PLUS_EXPR, op1, op0);
7730       else
7731         common = 1;
7732       break;
7733
7734     case MINUS_EXPR:
7735       /* Subtraction of two similar pointers.
7736          We must subtract them as integers, then divide by object size.  */
7737       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7738           && comp_target_types (type0, type1))
7739         return pointer_diff (op0, op1);
7740       /* Handle pointer minus int.  Just like pointer plus int.  */
7741       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7742         return pointer_int_sum (MINUS_EXPR, op0, op1);
7743       else
7744         common = 1;
7745       break;
7746
7747     case MULT_EXPR:
7748       common = 1;
7749       break;
7750
7751     case TRUNC_DIV_EXPR:
7752     case CEIL_DIV_EXPR:
7753     case FLOOR_DIV_EXPR:
7754     case ROUND_DIV_EXPR:
7755     case EXACT_DIV_EXPR:
7756       /* Floating point division by zero is a legitimate way to obtain
7757          infinities and NaNs.  */
7758       if (skip_evaluation == 0 && integer_zerop (op1))
7759         warning (OPT_Wdiv_by_zero, "division by zero");
7760
7761       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7762            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7763           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7764               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7765         {
7766           enum tree_code tcode0 = code0, tcode1 = code1;
7767
7768           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7769             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7770           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7771             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7772
7773           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7774             resultcode = RDIV_EXPR;
7775           else
7776             /* Although it would be tempting to shorten always here, that
7777                loses on some targets, since the modulo instruction is
7778                undefined if the quotient can't be represented in the
7779                computation mode.  We shorten only if unsigned or if
7780                dividing by something we know != -1.  */
7781             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7782                        || (TREE_CODE (op1) == INTEGER_CST
7783                            && !integer_all_onesp (op1)));
7784           common = 1;
7785         }
7786       break;
7787
7788     case BIT_AND_EXPR:
7789     case BIT_IOR_EXPR:
7790     case BIT_XOR_EXPR:
7791       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7792         shorten = -1;
7793       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7794         common = 1;
7795       break;
7796
7797     case TRUNC_MOD_EXPR:
7798     case FLOOR_MOD_EXPR:
7799       if (skip_evaluation == 0 && integer_zerop (op1))
7800         warning (OPT_Wdiv_by_zero, "division by zero");
7801
7802       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7803         {
7804           /* Although it would be tempting to shorten always here, that loses
7805              on some targets, since the modulo instruction is undefined if the
7806              quotient can't be represented in the computation mode.  We shorten
7807              only if unsigned or if dividing by something we know != -1.  */
7808           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7809                      || (TREE_CODE (op1) == INTEGER_CST
7810                          && !integer_all_onesp (op1)));
7811           common = 1;
7812         }
7813       break;
7814
7815     case TRUTH_ANDIF_EXPR:
7816     case TRUTH_ORIF_EXPR:
7817     case TRUTH_AND_EXPR:
7818     case TRUTH_OR_EXPR:
7819     case TRUTH_XOR_EXPR:
7820       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7821            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7822           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7823               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7824         {
7825           /* Result of these operations is always an int,
7826              but that does not mean the operands should be
7827              converted to ints!  */
7828           result_type = integer_type_node;
7829           op0 = c_common_truthvalue_conversion (op0);
7830           op1 = c_common_truthvalue_conversion (op1);
7831           converted = 1;
7832         }
7833       break;
7834
7835       /* Shift operations: result has same type as first operand;
7836          always convert second operand to int.
7837          Also set SHORT_SHIFT if shifting rightward.  */
7838
7839     case RSHIFT_EXPR:
7840       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7841         {
7842           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7843             {
7844               if (tree_int_cst_sgn (op1) < 0)
7845                 warning (0, "right shift count is negative");
7846               else
7847                 {
7848                   if (!integer_zerop (op1))
7849                     short_shift = 1;
7850
7851                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7852                     warning (0, "right shift count >= width of type");
7853                 }
7854             }
7855
7856           /* Use the type of the value to be shifted.  */
7857           result_type = type0;
7858           /* Convert the shift-count to an integer, regardless of size
7859              of value being shifted.  */
7860           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7861             op1 = convert (integer_type_node, op1);
7862           /* Avoid converting op1 to result_type later.  */
7863           converted = 1;
7864         }
7865       break;
7866
7867     case LSHIFT_EXPR:
7868       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7869         {
7870           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7871             {
7872               if (tree_int_cst_sgn (op1) < 0)
7873                 warning (0, "left shift count is negative");
7874
7875               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7876                 warning (0, "left shift count >= width of type");
7877             }
7878
7879           /* Use the type of the value to be shifted.  */
7880           result_type = type0;
7881           /* Convert the shift-count to an integer, regardless of size
7882              of value being shifted.  */
7883           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7884             op1 = convert (integer_type_node, op1);
7885           /* Avoid converting op1 to result_type later.  */
7886           converted = 1;
7887         }
7888       break;
7889
7890     case EQ_EXPR:
7891     case NE_EXPR:
7892       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7893         warning (OPT_Wfloat_equal,
7894                  "comparing floating point with == or != is unsafe");
7895       /* Result of comparison is always int,
7896          but don't convert the args to int!  */
7897       build_type = integer_type_node;
7898       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7899            || code0 == COMPLEX_TYPE)
7900           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7901               || code1 == COMPLEX_TYPE))
7902         short_compare = 1;
7903       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7904         {
7905           tree tt0 = TREE_TYPE (type0);
7906           tree tt1 = TREE_TYPE (type1);
7907           /* Anything compares with void *.  void * compares with anything.
7908              Otherwise, the targets must be compatible
7909              and both must be object or both incomplete.  */
7910           if (comp_target_types (type0, type1))
7911             result_type = common_pointer_type (type0, type1);
7912           else if (VOID_TYPE_P (tt0))
7913             {
7914               /* op0 != orig_op0 detects the case of something
7915                  whose value is 0 but which isn't a valid null ptr const.  */
7916               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7917                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7918                 pedwarn ("ISO C forbids comparison of %<void *%>"
7919                          " with function pointer");
7920             }
7921           else if (VOID_TYPE_P (tt1))
7922             {
7923               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7924                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7925                 pedwarn ("ISO C forbids comparison of %<void *%>"
7926                          " with function pointer");
7927             }
7928           else
7929             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7930             if (!objc_ok)
7931               pedwarn ("comparison of distinct pointer types lacks a cast");
7932
7933           if (result_type == NULL_TREE)
7934             result_type = ptr_type_node;
7935         }
7936       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7937                && integer_zerop (op1))
7938         result_type = type0;
7939       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7940                && integer_zerop (op0))
7941         result_type = type1;
7942       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7943         {
7944           result_type = type0;
7945           pedwarn ("comparison between pointer and integer");
7946         }
7947       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7948         {
7949           result_type = type1;
7950           pedwarn ("comparison between pointer and integer");
7951         }
7952       break;
7953
7954     case LE_EXPR:
7955     case GE_EXPR:
7956     case LT_EXPR:
7957     case GT_EXPR:
7958       build_type = integer_type_node;
7959       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7960           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7961         short_compare = 1;
7962       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7963         {
7964           if (comp_target_types (type0, type1))
7965             {
7966               result_type = common_pointer_type (type0, type1);
7967               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7968                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7969                 pedwarn ("comparison of complete and incomplete pointers");
7970               else if (pedantic
7971                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7972                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7973             }
7974           else
7975             {
7976               result_type = ptr_type_node;
7977               pedwarn ("comparison of distinct pointer types lacks a cast");
7978             }
7979         }
7980       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7981                && integer_zerop (op1))
7982         {
7983           result_type = type0;
7984           if (pedantic || extra_warnings)
7985             pedwarn ("ordered comparison of pointer with integer zero");
7986         }
7987       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7988                && integer_zerop (op0))
7989         {
7990           result_type = type1;
7991           if (pedantic)
7992             pedwarn ("ordered comparison of pointer with integer zero");
7993         }
7994       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7995         {
7996           result_type = type0;
7997           pedwarn ("comparison between pointer and integer");
7998         }
7999       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8000         {
8001           result_type = type1;
8002           pedwarn ("comparison between pointer and integer");
8003         }
8004       break;
8005
8006     default:
8007       gcc_unreachable ();
8008     }
8009
8010   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8011     return error_mark_node;
8012
8013   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8014       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8015           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8016                                                     TREE_TYPE (type1))))
8017     {
8018       binary_op_error (code);
8019       return error_mark_node;
8020     }
8021
8022   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8023        || code0 == VECTOR_TYPE)
8024       &&
8025       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8026        || code1 == VECTOR_TYPE))
8027     {
8028       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8029
8030       if (shorten || common || short_compare)
8031         result_type = c_common_type (type0, type1);
8032
8033       /* For certain operations (which identify themselves by shorten != 0)
8034          if both args were extended from the same smaller type,
8035          do the arithmetic in that type and then extend.
8036
8037          shorten !=0 and !=1 indicates a bitwise operation.
8038          For them, this optimization is safe only if
8039          both args are zero-extended or both are sign-extended.
8040          Otherwise, we might change the result.
8041          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8042          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8043
8044       if (shorten && none_complex)
8045         {
8046           int unsigned0, unsigned1;
8047           tree arg0 = get_narrower (op0, &unsigned0);
8048           tree arg1 = get_narrower (op1, &unsigned1);
8049           /* UNS is 1 if the operation to be done is an unsigned one.  */
8050           int uns = TYPE_UNSIGNED (result_type);
8051           tree type;
8052
8053           final_type = result_type;
8054
8055           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8056              but it *requires* conversion to FINAL_TYPE.  */
8057
8058           if ((TYPE_PRECISION (TREE_TYPE (op0))
8059                == TYPE_PRECISION (TREE_TYPE (arg0)))
8060               && TREE_TYPE (op0) != final_type)
8061             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8062           if ((TYPE_PRECISION (TREE_TYPE (op1))
8063                == TYPE_PRECISION (TREE_TYPE (arg1)))
8064               && TREE_TYPE (op1) != final_type)
8065             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8066
8067           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8068
8069           /* For bitwise operations, signedness of nominal type
8070              does not matter.  Consider only how operands were extended.  */
8071           if (shorten == -1)
8072             uns = unsigned0;
8073
8074           /* Note that in all three cases below we refrain from optimizing
8075              an unsigned operation on sign-extended args.
8076              That would not be valid.  */
8077
8078           /* Both args variable: if both extended in same way
8079              from same width, do it in that width.
8080              Do it unsigned if args were zero-extended.  */
8081           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8082                < TYPE_PRECISION (result_type))
8083               && (TYPE_PRECISION (TREE_TYPE (arg1))
8084                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8085               && unsigned0 == unsigned1
8086               && (unsigned0 || !uns))
8087             result_type
8088               = c_common_signed_or_unsigned_type
8089               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8090           else if (TREE_CODE (arg0) == INTEGER_CST
8091                    && (unsigned1 || !uns)
8092                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8093                        < TYPE_PRECISION (result_type))
8094                    && (type
8095                        = c_common_signed_or_unsigned_type (unsigned1,
8096                                                            TREE_TYPE (arg1)),
8097                        int_fits_type_p (arg0, type)))
8098             result_type = type;
8099           else if (TREE_CODE (arg1) == INTEGER_CST
8100                    && (unsigned0 || !uns)
8101                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8102                        < TYPE_PRECISION (result_type))
8103                    && (type
8104                        = c_common_signed_or_unsigned_type (unsigned0,
8105                                                            TREE_TYPE (arg0)),
8106                        int_fits_type_p (arg1, type)))
8107             result_type = type;
8108         }
8109
8110       /* Shifts can be shortened if shifting right.  */
8111
8112       if (short_shift)
8113         {
8114           int unsigned_arg;
8115           tree arg0 = get_narrower (op0, &unsigned_arg);
8116
8117           final_type = result_type;
8118
8119           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8120             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8121
8122           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8123               /* We can shorten only if the shift count is less than the
8124                  number of bits in the smaller type size.  */
8125               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8126               /* We cannot drop an unsigned shift after sign-extension.  */
8127               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8128             {
8129               /* Do an unsigned shift if the operand was zero-extended.  */
8130               result_type
8131                 = c_common_signed_or_unsigned_type (unsigned_arg,
8132                                                     TREE_TYPE (arg0));
8133               /* Convert value-to-be-shifted to that type.  */
8134               if (TREE_TYPE (op0) != result_type)
8135                 op0 = convert (result_type, op0);
8136               converted = 1;
8137             }
8138         }
8139
8140       /* Comparison operations are shortened too but differently.
8141          They identify themselves by setting short_compare = 1.  */
8142
8143       if (short_compare)
8144         {
8145           /* Don't write &op0, etc., because that would prevent op0
8146              from being kept in a register.
8147              Instead, make copies of the our local variables and
8148              pass the copies by reference, then copy them back afterward.  */
8149           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8150           enum tree_code xresultcode = resultcode;
8151           tree val
8152             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8153
8154           if (val != 0)
8155             return val;
8156
8157           op0 = xop0, op1 = xop1;
8158           converted = 1;
8159           resultcode = xresultcode;
8160
8161           if (warn_sign_compare && skip_evaluation == 0)
8162             {
8163               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8164               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8165               int unsignedp0, unsignedp1;
8166               tree primop0 = get_narrower (op0, &unsignedp0);
8167               tree primop1 = get_narrower (op1, &unsignedp1);
8168
8169               xop0 = orig_op0;
8170               xop1 = orig_op1;
8171               STRIP_TYPE_NOPS (xop0);
8172               STRIP_TYPE_NOPS (xop1);
8173
8174               /* Give warnings for comparisons between signed and unsigned
8175                  quantities that may fail.
8176
8177                  Do the checking based on the original operand trees, so that
8178                  casts will be considered, but default promotions won't be.
8179
8180                  Do not warn if the comparison is being done in a signed type,
8181                  since the signed type will only be chosen if it can represent
8182                  all the values of the unsigned type.  */
8183               if (!TYPE_UNSIGNED (result_type))
8184                 /* OK */;
8185               /* Do not warn if both operands are the same signedness.  */
8186               else if (op0_signed == op1_signed)
8187                 /* OK */;
8188               else
8189                 {
8190                   tree sop, uop;
8191
8192                   if (op0_signed)
8193                     sop = xop0, uop = xop1;
8194                   else
8195                     sop = xop1, uop = xop0;
8196
8197                   /* Do not warn if the signed quantity is an
8198                      unsuffixed integer literal (or some static
8199                      constant expression involving such literals or a
8200                      conditional expression involving such literals)
8201                      and it is non-negative.  */
8202                   if (tree_expr_nonnegative_p (sop))
8203                     /* OK */;
8204                   /* Do not warn if the comparison is an equality operation,
8205                      the unsigned quantity is an integral constant, and it
8206                      would fit in the result if the result were signed.  */
8207                   else if (TREE_CODE (uop) == INTEGER_CST
8208                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8209                            && int_fits_type_p
8210                            (uop, c_common_signed_type (result_type)))
8211                     /* OK */;
8212                   /* Do not warn if the unsigned quantity is an enumeration
8213                      constant and its maximum value would fit in the result
8214                      if the result were signed.  */
8215                   else if (TREE_CODE (uop) == INTEGER_CST
8216                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8217                            && int_fits_type_p
8218                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8219                             c_common_signed_type (result_type)))
8220                     /* OK */;
8221                   else
8222                     warning (0, "comparison between signed and unsigned");
8223                 }
8224
8225               /* Warn if two unsigned values are being compared in a size
8226                  larger than their original size, and one (and only one) is the
8227                  result of a `~' operator.  This comparison will always fail.
8228
8229                  Also warn if one operand is a constant, and the constant
8230                  does not have all bits set that are set in the ~ operand
8231                  when it is extended.  */
8232
8233               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8234                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8235                 {
8236                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8237                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8238                                             &unsignedp0);
8239                   else
8240                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8241                                             &unsignedp1);
8242
8243                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8244                     {
8245                       tree primop;
8246                       HOST_WIDE_INT constant, mask;
8247                       int unsignedp, bits;
8248
8249                       if (host_integerp (primop0, 0))
8250                         {
8251                           primop = primop1;
8252                           unsignedp = unsignedp1;
8253                           constant = tree_low_cst (primop0, 0);
8254                         }
8255                       else
8256                         {
8257                           primop = primop0;
8258                           unsignedp = unsignedp0;
8259                           constant = tree_low_cst (primop1, 0);
8260                         }
8261
8262                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8263                       if (bits < TYPE_PRECISION (result_type)
8264                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8265                         {
8266                           mask = (~(HOST_WIDE_INT) 0) << bits;
8267                           if ((mask & constant) != mask)
8268                             warning (0, "comparison of promoted ~unsigned with constant");
8269                         }
8270                     }
8271                   else if (unsignedp0 && unsignedp1
8272                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8273                                < TYPE_PRECISION (result_type))
8274                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8275                                < TYPE_PRECISION (result_type)))
8276                     warning (0, "comparison of promoted ~unsigned with unsigned");
8277                 }
8278             }
8279         }
8280     }
8281
8282   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8283      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8284      Then the expression will be built.
8285      It will be given type FINAL_TYPE if that is nonzero;
8286      otherwise, it will be given type RESULT_TYPE.  */
8287
8288   if (!result_type)
8289     {
8290       binary_op_error (code);
8291       return error_mark_node;
8292     }
8293
8294   if (!converted)
8295     {
8296       if (TREE_TYPE (op0) != result_type)
8297         op0 = convert (result_type, op0);
8298       if (TREE_TYPE (op1) != result_type)
8299         op1 = convert (result_type, op1);
8300
8301       /* This can happen if one operand has a vector type, and the other
8302          has a different type.  */
8303       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8304         return error_mark_node;
8305     }
8306
8307   if (build_type == NULL_TREE)
8308     build_type = result_type;
8309
8310   {
8311     /* Treat expressions in initializers specially as they can't trap.  */
8312     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8313                                                                     build_type,
8314                                                                     op0, op1)
8315                                          : fold_build2 (resultcode, build_type,
8316                                                         op0, op1);
8317
8318     if (final_type != 0)
8319       result = convert (final_type, result);
8320     return result;
8321   }
8322 }
8323
8324
8325 /* Convert EXPR to be a truth-value, validating its type for this
8326    purpose.  */
8327
8328 tree
8329 c_objc_common_truthvalue_conversion (tree expr)
8330 {
8331   switch (TREE_CODE (TREE_TYPE (expr)))
8332     {
8333     case ARRAY_TYPE:
8334       error ("used array that cannot be converted to pointer where scalar is required");
8335       return error_mark_node;
8336
8337     case RECORD_TYPE:
8338       error ("used struct type value where scalar is required");
8339       return error_mark_node;
8340
8341     case UNION_TYPE:
8342       error ("used union type value where scalar is required");
8343       return error_mark_node;
8344
8345     case FUNCTION_TYPE:
8346       gcc_unreachable ();
8347
8348     default:
8349       break;
8350     }
8351
8352   /* ??? Should we also give an error for void and vectors rather than
8353      leaving those to give errors later?  */
8354   return c_common_truthvalue_conversion (expr);
8355 }
8356 \f
8357
8358 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8359    required.  */
8360
8361 tree
8362 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8363                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8364 {
8365   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8366     {
8367       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8368       /* Executing a compound literal inside a function reinitializes
8369          it.  */
8370       if (!TREE_STATIC (decl))
8371         *se = true;
8372       return decl;
8373     }
8374   else
8375     return expr;
8376 }