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 compatiable, 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   /* Subscripting with type char is likely to lose on a machine where
1863      chars are signed.  So warn on any machine, but optionally.  Don't
1864      warn for unsigned char since that type is safe.  Don't warn for
1865      signed char because anyone who uses that must have done so
1866      deliberately.  ??? Existing practice has also been to warn only
1867      when the char index is syntactically the index, not for
1868      char[array].  */
1869   if (!swapped
1870       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1871     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
1872
1873   /* Apply default promotions *after* noticing character types.  */
1874   index = default_conversion (index);
1875
1876   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1877
1878   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1879     {
1880       tree rval, type;
1881
1882       /* An array that is indexed by a non-constant
1883          cannot be stored in a register; we must be able to do
1884          address arithmetic on its address.
1885          Likewise an array of elements of variable size.  */
1886       if (TREE_CODE (index) != INTEGER_CST
1887           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1888               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1889         {
1890           if (!c_mark_addressable (array))
1891             return error_mark_node;
1892         }
1893       /* An array that is indexed by a constant value which is not within
1894          the array bounds cannot be stored in a register either; because we
1895          would get a crash in store_bit_field/extract_bit_field when trying
1896          to access a non-existent part of the register.  */
1897       if (TREE_CODE (index) == INTEGER_CST
1898           && TYPE_DOMAIN (TREE_TYPE (array))
1899           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1900         {
1901           if (!c_mark_addressable (array))
1902             return error_mark_node;
1903         }
1904
1905       if (pedantic)
1906         {
1907           tree foo = array;
1908           while (TREE_CODE (foo) == COMPONENT_REF)
1909             foo = TREE_OPERAND (foo, 0);
1910           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1911             pedwarn ("ISO C forbids subscripting %<register%> array");
1912           else if (!flag_isoc99 && !lvalue_p (foo))
1913             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1914         }
1915
1916       type = TREE_TYPE (TREE_TYPE (array));
1917       if (TREE_CODE (type) != ARRAY_TYPE)
1918         type = TYPE_MAIN_VARIANT (type);
1919       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1920       /* Array ref is const/volatile if the array elements are
1921          or if the array is.  */
1922       TREE_READONLY (rval)
1923         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1924             | TREE_READONLY (array));
1925       TREE_SIDE_EFFECTS (rval)
1926         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1927             | TREE_SIDE_EFFECTS (array));
1928       TREE_THIS_VOLATILE (rval)
1929         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1930             /* This was added by rms on 16 Nov 91.
1931                It fixes  vol struct foo *a;  a->elts[1]
1932                in an inline function.
1933                Hope it doesn't break something else.  */
1934             | TREE_THIS_VOLATILE (array));
1935       return require_complete_type (fold (rval));
1936     }
1937   else
1938     {
1939       tree ar = default_conversion (array);
1940
1941       if (ar == error_mark_node)
1942         return ar;
1943
1944       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1945       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1946
1947       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1948                                  "array indexing");
1949     }
1950 }
1951 \f
1952 /* Build an external reference to identifier ID.  FUN indicates
1953    whether this will be used for a function call.  LOC is the source
1954    location of the identifier.  */
1955 tree
1956 build_external_ref (tree id, int fun, location_t loc)
1957 {
1958   tree ref;
1959   tree decl = lookup_name (id);
1960
1961   /* In Objective-C, an instance variable (ivar) may be preferred to
1962      whatever lookup_name() found.  */
1963   decl = objc_lookup_ivar (decl, id);
1964
1965   if (decl && decl != error_mark_node)
1966     ref = decl;
1967   else if (fun)
1968     /* Implicit function declaration.  */
1969     ref = implicitly_declare (id);
1970   else if (decl == error_mark_node)
1971     /* Don't complain about something that's already been
1972        complained about.  */
1973     return error_mark_node;
1974   else
1975     {
1976       undeclared_variable (id, loc);
1977       return error_mark_node;
1978     }
1979
1980   if (TREE_TYPE (ref) == error_mark_node)
1981     return error_mark_node;
1982
1983   if (TREE_DEPRECATED (ref))
1984     warn_deprecated_use (ref);
1985
1986   if (!skip_evaluation)
1987     assemble_external (ref);
1988   TREE_USED (ref) = 1;
1989
1990   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1991     {
1992       if (!in_sizeof && !in_typeof)
1993         C_DECL_USED (ref) = 1;
1994       else if (DECL_INITIAL (ref) == 0
1995                && DECL_EXTERNAL (ref)
1996                && !TREE_PUBLIC (ref))
1997         record_maybe_used_decl (ref);
1998     }
1999
2000   if (TREE_CODE (ref) == CONST_DECL)
2001     {
2002       ref = DECL_INITIAL (ref);
2003       TREE_CONSTANT (ref) = 1;
2004       TREE_INVARIANT (ref) = 1;
2005     }
2006   else if (current_function_decl != 0
2007            && !DECL_FILE_SCOPE_P (current_function_decl)
2008            && (TREE_CODE (ref) == VAR_DECL
2009                || TREE_CODE (ref) == PARM_DECL
2010                || TREE_CODE (ref) == FUNCTION_DECL))
2011     {
2012       tree context = decl_function_context (ref);
2013
2014       if (context != 0 && context != current_function_decl)
2015         DECL_NONLOCAL (ref) = 1;
2016     }
2017
2018   return ref;
2019 }
2020
2021 /* Record details of decls possibly used inside sizeof or typeof.  */
2022 struct maybe_used_decl
2023 {
2024   /* The decl.  */
2025   tree decl;
2026   /* The level seen at (in_sizeof + in_typeof).  */
2027   int level;
2028   /* The next one at this level or above, or NULL.  */
2029   struct maybe_used_decl *next;
2030 };
2031
2032 static struct maybe_used_decl *maybe_used_decls;
2033
2034 /* Record that DECL, an undefined static function reference seen
2035    inside sizeof or typeof, might be used if the operand of sizeof is
2036    a VLA type or the operand of typeof is a variably modified
2037    type.  */
2038
2039 static void
2040 record_maybe_used_decl (tree decl)
2041 {
2042   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2043   t->decl = decl;
2044   t->level = in_sizeof + in_typeof;
2045   t->next = maybe_used_decls;
2046   maybe_used_decls = t;
2047 }
2048
2049 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2050    USED is false, just discard them.  If it is true, mark them used
2051    (if no longer inside sizeof or typeof) or move them to the next
2052    level up (if still inside sizeof or typeof).  */
2053
2054 void
2055 pop_maybe_used (bool used)
2056 {
2057   struct maybe_used_decl *p = maybe_used_decls;
2058   int cur_level = in_sizeof + in_typeof;
2059   while (p && p->level > cur_level)
2060     {
2061       if (used)
2062         {
2063           if (cur_level == 0)
2064             C_DECL_USED (p->decl) = 1;
2065           else
2066             p->level = cur_level;
2067         }
2068       p = p->next;
2069     }
2070   if (!used || cur_level == 0)
2071     maybe_used_decls = p;
2072 }
2073
2074 /* Return the result of sizeof applied to EXPR.  */
2075
2076 struct c_expr
2077 c_expr_sizeof_expr (struct c_expr expr)
2078 {
2079   struct c_expr ret;
2080   if (expr.value == error_mark_node)
2081     {
2082       ret.value = error_mark_node;
2083       ret.original_code = ERROR_MARK;
2084       pop_maybe_used (false);
2085     }
2086   else
2087     {
2088       ret.value = c_sizeof (TREE_TYPE (expr.value));
2089       ret.original_code = ERROR_MARK;
2090       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2091     }
2092   return ret;
2093 }
2094
2095 /* Return the result of sizeof applied to T, a structure for the type
2096    name passed to sizeof (rather than the type itself).  */
2097
2098 struct c_expr
2099 c_expr_sizeof_type (struct c_type_name *t)
2100 {
2101   tree type;
2102   struct c_expr ret;
2103   type = groktypename (t);
2104   ret.value = c_sizeof (type);
2105   ret.original_code = ERROR_MARK;
2106   pop_maybe_used (C_TYPE_VARIABLE_SIZE (type));
2107   return ret;
2108 }
2109
2110 /* Build a function call to function FUNCTION with parameters PARAMS.
2111    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2112    TREE_VALUE of each node is a parameter-expression.
2113    FUNCTION's data type may be a function type or a pointer-to-function.  */
2114
2115 tree
2116 build_function_call (tree function, tree params)
2117 {
2118   tree fntype, fundecl = 0;
2119   tree coerced_params;
2120   tree name = NULL_TREE, result;
2121   tree tem;
2122
2123   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2124   STRIP_TYPE_NOPS (function);
2125
2126   /* Convert anything with function type to a pointer-to-function.  */
2127   if (TREE_CODE (function) == FUNCTION_DECL)
2128     {
2129       /* Implement type-directed function overloading for builtins.
2130          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2131          handle all the type checking.  The result is a complete expression
2132          that implements this function call.  */
2133       tem = resolve_overloaded_builtin (function, params);
2134       if (tem)
2135         return tem;
2136
2137       name = DECL_NAME (function);
2138       fundecl = function;
2139     }
2140   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2141     function = function_to_pointer_conversion (function);
2142
2143   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2144      expressions, like those used for ObjC messenger dispatches.  */
2145   function = objc_rewrite_function_call (function, params);
2146
2147   fntype = TREE_TYPE (function);
2148
2149   if (TREE_CODE (fntype) == ERROR_MARK)
2150     return error_mark_node;
2151
2152   if (!(TREE_CODE (fntype) == POINTER_TYPE
2153         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2154     {
2155       error ("called object %qE is not a function", function);
2156       return error_mark_node;
2157     }
2158
2159   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2160     current_function_returns_abnormally = 1;
2161
2162   /* fntype now gets the type of function pointed to.  */
2163   fntype = TREE_TYPE (fntype);
2164
2165   /* Check that the function is called through a compatible prototype.
2166      If it is not, replace the call by a trap, wrapped up in a compound
2167      expression if necessary.  This has the nice side-effect to prevent
2168      the tree-inliner from generating invalid assignment trees which may
2169      blow up in the RTL expander later.  */
2170   if (TREE_CODE (function) == NOP_EXPR
2171       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2172       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2173       && !comptypes (fntype, TREE_TYPE (tem)))
2174     {
2175       tree return_type = TREE_TYPE (fntype);
2176       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2177                                        NULL_TREE);
2178
2179       /* This situation leads to run-time undefined behavior.  We can't,
2180          therefore, simply error unless we can prove that all possible
2181          executions of the program must execute the code.  */
2182       warning (0, "function called through a non-compatible type");
2183
2184       /* We can, however, treat "undefined" any way we please.
2185          Call abort to encourage the user to fix the program.  */
2186       inform ("if this code is reached, the program will abort");
2187
2188       if (VOID_TYPE_P (return_type))
2189         return trap;
2190       else
2191         {
2192           tree rhs;
2193
2194           if (AGGREGATE_TYPE_P (return_type))
2195             rhs = build_compound_literal (return_type,
2196                                           build_constructor (return_type, 0));
2197           else
2198             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2199
2200           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2201         }
2202     }
2203
2204   /* Convert the parameters to the types declared in the
2205      function prototype, or apply default promotions.  */
2206
2207   coerced_params
2208     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2209
2210   if (coerced_params == error_mark_node)
2211     return error_mark_node;
2212
2213   /* Check that the arguments to the function are valid.  */
2214
2215   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2216                             TYPE_ARG_TYPES (fntype));
2217
2218   if (require_constant_value)
2219     {
2220       result = fold_build3_initializer (CALL_EXPR, TREE_TYPE (fntype),
2221                                         function, coerced_params, NULL_TREE);
2222
2223       if (TREE_CONSTANT (result)
2224           && (name == NULL_TREE
2225               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2226         pedwarn_init ("initializer element is not constant");
2227     }
2228   else
2229     result = fold_build3 (CALL_EXPR, TREE_TYPE (fntype),
2230                           function, coerced_params, NULL_TREE);
2231
2232   if (VOID_TYPE_P (TREE_TYPE (result)))
2233     return result;
2234   return require_complete_type (result);
2235 }
2236 \f
2237 /* Convert the argument expressions in the list VALUES
2238    to the types in the list TYPELIST.  The result is a list of converted
2239    argument expressions, unless there are too few arguments in which
2240    case it is error_mark_node.
2241
2242    If TYPELIST is exhausted, or when an element has NULL as its type,
2243    perform the default conversions.
2244
2245    PARMLIST is the chain of parm decls for the function being called.
2246    It may be 0, if that info is not available.
2247    It is used only for generating error messages.
2248
2249    FUNCTION is a tree for the called function.  It is used only for
2250    error messages, where it is formatted with %qE.
2251
2252    This is also where warnings about wrong number of args are generated.
2253
2254    Both VALUES and the returned value are chains of TREE_LIST nodes
2255    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2256
2257 static tree
2258 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2259 {
2260   tree typetail, valtail;
2261   tree result = NULL;
2262   int parmnum;
2263   tree selector;
2264
2265   /* Change pointer to function to the function itself for
2266      diagnostics.  */
2267   if (TREE_CODE (function) == ADDR_EXPR
2268       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2269     function = TREE_OPERAND (function, 0);
2270
2271   /* Handle an ObjC selector specially for diagnostics.  */
2272   selector = objc_message_selector ();
2273
2274   /* Scan the given expressions and types, producing individual
2275      converted arguments and pushing them on RESULT in reverse order.  */
2276
2277   for (valtail = values, typetail = typelist, parmnum = 0;
2278        valtail;
2279        valtail = TREE_CHAIN (valtail), parmnum++)
2280     {
2281       tree type = typetail ? TREE_VALUE (typetail) : 0;
2282       tree val = TREE_VALUE (valtail);
2283       tree rname = function;
2284       int argnum = parmnum + 1;
2285       const char *invalid_func_diag;
2286
2287       if (type == void_type_node)
2288         {
2289           error ("too many arguments to function %qE", function);
2290           break;
2291         }
2292
2293       if (selector && argnum > 2)
2294         {
2295           rname = selector;
2296           argnum -= 2;
2297         }
2298
2299       STRIP_TYPE_NOPS (val);
2300
2301       val = require_complete_type (val);
2302
2303       if (type != 0)
2304         {
2305           /* Formal parm type is specified by a function prototype.  */
2306           tree parmval;
2307
2308           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2309             {
2310               error ("type of formal parameter %d is incomplete", parmnum + 1);
2311               parmval = val;
2312             }
2313           else
2314             {
2315               /* Optionally warn about conversions that
2316                  differ from the default conversions.  */
2317               if (warn_conversion || warn_traditional)
2318                 {
2319                   unsigned int formal_prec = TYPE_PRECISION (type);
2320
2321                   if (INTEGRAL_TYPE_P (type)
2322                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2323                     warning (0, "passing argument %d of %qE as integer "
2324                              "rather than floating due to prototype",
2325                              argnum, rname);
2326                   if (INTEGRAL_TYPE_P (type)
2327                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2328                     warning (0, "passing argument %d of %qE as integer "
2329                              "rather than complex due to prototype",
2330                              argnum, rname);
2331                   else if (TREE_CODE (type) == COMPLEX_TYPE
2332                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2333                     warning (0, "passing argument %d of %qE as complex "
2334                              "rather than floating due to prototype",
2335                              argnum, rname);
2336                   else if (TREE_CODE (type) == REAL_TYPE
2337                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2338                     warning (0, "passing argument %d of %qE as floating "
2339                              "rather than integer due to prototype",
2340                              argnum, rname);
2341                   else if (TREE_CODE (type) == COMPLEX_TYPE
2342                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2343                     warning (0, "passing argument %d of %qE as complex "
2344                              "rather than integer due to prototype",
2345                              argnum, rname);
2346                   else if (TREE_CODE (type) == REAL_TYPE
2347                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2348                     warning (0, "passing argument %d of %qE as floating "
2349                              "rather than complex due to prototype",
2350                              argnum, rname);
2351                   /* ??? At some point, messages should be written about
2352                      conversions between complex types, but that's too messy
2353                      to do now.  */
2354                   else if (TREE_CODE (type) == REAL_TYPE
2355                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2356                     {
2357                       /* Warn if any argument is passed as `float',
2358                          since without a prototype it would be `double'.  */
2359                       if (formal_prec == TYPE_PRECISION (float_type_node))
2360                         warning (0, "passing argument %d of %qE as %<float%> "
2361                                  "rather than %<double%> due to prototype",
2362                                  argnum, rname);
2363                     }
2364                   /* Detect integer changing in width or signedness.
2365                      These warnings are only activated with
2366                      -Wconversion, not with -Wtraditional.  */
2367                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2368                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2369                     {
2370                       tree would_have_been = default_conversion (val);
2371                       tree type1 = TREE_TYPE (would_have_been);
2372
2373                       if (TREE_CODE (type) == ENUMERAL_TYPE
2374                           && (TYPE_MAIN_VARIANT (type)
2375                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2376                         /* No warning if function asks for enum
2377                            and the actual arg is that enum type.  */
2378                         ;
2379                       else if (formal_prec != TYPE_PRECISION (type1))
2380                         warning (OPT_Wconversion, "passing argument %d of %qE "
2381                                  "with different width due to prototype",
2382                                  argnum, rname);
2383                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2384                         ;
2385                       /* Don't complain if the formal parameter type
2386                          is an enum, because we can't tell now whether
2387                          the value was an enum--even the same enum.  */
2388                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2389                         ;
2390                       else if (TREE_CODE (val) == INTEGER_CST
2391                                && int_fits_type_p (val, type))
2392                         /* Change in signedness doesn't matter
2393                            if a constant value is unaffected.  */
2394                         ;
2395                       /* If the value is extended from a narrower
2396                          unsigned type, it doesn't matter whether we
2397                          pass it as signed or unsigned; the value
2398                          certainly is the same either way.  */
2399                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2400                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2401                         ;
2402                       else if (TYPE_UNSIGNED (type))
2403                         warning (OPT_Wconversion, "passing argument %d of %qE "
2404                                  "as unsigned due to prototype",
2405                                  argnum, rname);
2406                       else
2407                         warning (OPT_Wconversion, "passing argument %d of %qE "
2408                                  "as signed due to prototype", argnum, rname);
2409                     }
2410                 }
2411
2412               parmval = convert_for_assignment (type, val, ic_argpass,
2413                                                 fundecl, function,
2414                                                 parmnum + 1);
2415
2416               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2417                   && INTEGRAL_TYPE_P (type)
2418                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2419                 parmval = default_conversion (parmval);
2420             }
2421           result = tree_cons (NULL_TREE, parmval, result);
2422         }
2423       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2424                && (TYPE_PRECISION (TREE_TYPE (val))
2425                    < TYPE_PRECISION (double_type_node)))
2426         /* Convert `float' to `double'.  */
2427         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2428       else if ((invalid_func_diag =
2429                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2430         {
2431           error (invalid_func_diag);
2432           return error_mark_node;
2433         }
2434       else
2435         /* Convert `short' and `char' to full-size `int'.  */
2436         result = tree_cons (NULL_TREE, default_conversion (val), result);
2437
2438       if (typetail)
2439         typetail = TREE_CHAIN (typetail);
2440     }
2441
2442   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2443     {
2444       error ("too few arguments to function %qE", function);
2445       return error_mark_node;
2446     }
2447
2448   return nreverse (result);
2449 }
2450 \f
2451 /* This is the entry point used by the parser to build unary operators
2452    in the input.  CODE, a tree_code, specifies the unary operator, and
2453    ARG is the operand.  For unary plus, the C parser currently uses
2454    CONVERT_EXPR for code.  */
2455
2456 struct c_expr
2457 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2458 {
2459   struct c_expr result;
2460
2461   result.original_code = ERROR_MARK;
2462   result.value = build_unary_op (code, arg.value, 0);
2463   overflow_warning (result.value);
2464   return result;
2465 }
2466
2467 /* This is the entry point used by the parser to build binary operators
2468    in the input.  CODE, a tree_code, specifies the binary operator, and
2469    ARG1 and ARG2 are the operands.  In addition to constructing the
2470    expression, we check for operands that were written with other binary
2471    operators in a way that is likely to confuse the user.  */
2472
2473 struct c_expr
2474 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2475                         struct c_expr arg2)
2476 {
2477   struct c_expr result;
2478
2479   enum tree_code code1 = arg1.original_code;
2480   enum tree_code code2 = arg2.original_code;
2481
2482   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2483   result.original_code = code;
2484
2485   if (TREE_CODE (result.value) == ERROR_MARK)
2486     return result;
2487
2488   /* Check for cases such as x+y<<z which users are likely
2489      to misinterpret.  */
2490   if (warn_parentheses)
2491     {
2492       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2493         {
2494           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2495               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2496             warning (OPT_Wparentheses,
2497                      "suggest parentheses around + or - inside shift");
2498         }
2499
2500       if (code == TRUTH_ORIF_EXPR)
2501         {
2502           if (code1 == TRUTH_ANDIF_EXPR
2503               || code2 == TRUTH_ANDIF_EXPR)
2504             warning (OPT_Wparentheses,
2505                      "suggest parentheses around && within ||");
2506         }
2507
2508       if (code == BIT_IOR_EXPR)
2509         {
2510           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2511               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2512               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2513               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2514             warning (OPT_Wparentheses,
2515                      "suggest parentheses around arithmetic in operand of |");
2516           /* Check cases like x|y==z */
2517           if (TREE_CODE_CLASS (code1) == tcc_comparison
2518               || TREE_CODE_CLASS (code2) == tcc_comparison)
2519             warning (OPT_Wparentheses,
2520                      "suggest parentheses around comparison in operand of |");
2521         }
2522
2523       if (code == BIT_XOR_EXPR)
2524         {
2525           if (code1 == BIT_AND_EXPR
2526               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2527               || code2 == BIT_AND_EXPR
2528               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2529             warning (OPT_Wparentheses,
2530                      "suggest parentheses around arithmetic in operand of ^");
2531           /* Check cases like x^y==z */
2532           if (TREE_CODE_CLASS (code1) == tcc_comparison
2533               || TREE_CODE_CLASS (code2) == tcc_comparison)
2534             warning (OPT_Wparentheses,
2535                      "suggest parentheses around comparison in operand of ^");
2536         }
2537
2538       if (code == BIT_AND_EXPR)
2539         {
2540           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2541               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2542             warning (OPT_Wparentheses,
2543                      "suggest parentheses around + or - in operand of &");
2544           /* Check cases like x&y==z */
2545           if (TREE_CODE_CLASS (code1) == tcc_comparison
2546               || TREE_CODE_CLASS (code2) == tcc_comparison)
2547             warning (OPT_Wparentheses,
2548                      "suggest parentheses around comparison in operand of &");
2549         }
2550       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2551       if (TREE_CODE_CLASS (code) == tcc_comparison
2552           && (TREE_CODE_CLASS (code1) == tcc_comparison
2553               || TREE_CODE_CLASS (code2) == tcc_comparison))
2554         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2555                  "have their mathematical meaning");
2556
2557     }
2558
2559   unsigned_conversion_warning (result.value, arg1.value);
2560   unsigned_conversion_warning (result.value, arg2.value);
2561   overflow_warning (result.value);
2562
2563   return result;
2564 }
2565 \f
2566 /* Return a tree for the difference of pointers OP0 and OP1.
2567    The resulting tree has type int.  */
2568
2569 static tree
2570 pointer_diff (tree op0, tree op1)
2571 {
2572   tree restype = ptrdiff_type_node;
2573
2574   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2575   tree con0, con1, lit0, lit1;
2576   tree orig_op1 = op1;
2577
2578   if (pedantic || warn_pointer_arith)
2579     {
2580       if (TREE_CODE (target_type) == VOID_TYPE)
2581         pedwarn ("pointer of type %<void *%> used in subtraction");
2582       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2583         pedwarn ("pointer to a function used in subtraction");
2584     }
2585
2586   /* If the conversion to ptrdiff_type does anything like widening or
2587      converting a partial to an integral mode, we get a convert_expression
2588      that is in the way to do any simplifications.
2589      (fold-const.c doesn't know that the extra bits won't be needed.
2590      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2591      different mode in place.)
2592      So first try to find a common term here 'by hand'; we want to cover
2593      at least the cases that occur in legal static initializers.  */
2594   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2595   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2596
2597   if (TREE_CODE (con0) == PLUS_EXPR)
2598     {
2599       lit0 = TREE_OPERAND (con0, 1);
2600       con0 = TREE_OPERAND (con0, 0);
2601     }
2602   else
2603     lit0 = integer_zero_node;
2604
2605   if (TREE_CODE (con1) == PLUS_EXPR)
2606     {
2607       lit1 = TREE_OPERAND (con1, 1);
2608       con1 = TREE_OPERAND (con1, 0);
2609     }
2610   else
2611     lit1 = integer_zero_node;
2612
2613   if (operand_equal_p (con0, con1, 0))
2614     {
2615       op0 = lit0;
2616       op1 = lit1;
2617     }
2618
2619
2620   /* First do the subtraction as integers;
2621      then drop through to build the divide operator.
2622      Do not do default conversions on the minus operator
2623      in case restype is a short type.  */
2624
2625   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2626                          convert (restype, op1), 0);
2627   /* This generates an error if op1 is pointer to incomplete type.  */
2628   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2629     error ("arithmetic on pointer to an incomplete type");
2630
2631   /* This generates an error if op0 is pointer to incomplete type.  */
2632   op1 = c_size_in_bytes (target_type);
2633
2634   /* Divide by the size, in easiest possible way.  */
2635   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2636 }
2637 \f
2638 /* Construct and perhaps optimize a tree representation
2639    for a unary operation.  CODE, a tree_code, specifies the operation
2640    and XARG is the operand.
2641    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2642    the default promotions (such as from short to int).
2643    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2644    allows non-lvalues; this is only used to handle conversion of non-lvalue
2645    arrays to pointers in C99.  */
2646
2647 tree
2648 build_unary_op (enum tree_code code, tree xarg, int flag)
2649 {
2650   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2651   tree arg = xarg;
2652   tree argtype = 0;
2653   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2654   tree val;
2655   int noconvert = flag;
2656   const char *invalid_op_diag;
2657
2658   if (typecode == ERROR_MARK)
2659     return error_mark_node;
2660   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2661     typecode = INTEGER_TYPE;
2662
2663   if ((invalid_op_diag
2664        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2665     {
2666       error (invalid_op_diag);
2667       return error_mark_node;
2668     }
2669
2670   switch (code)
2671     {
2672     case CONVERT_EXPR:
2673       /* This is used for unary plus, because a CONVERT_EXPR
2674          is enough to prevent anybody from looking inside for
2675          associativity, but won't generate any code.  */
2676       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2677             || typecode == COMPLEX_TYPE
2678             || typecode == VECTOR_TYPE))
2679         {
2680           error ("wrong type argument to unary plus");
2681           return error_mark_node;
2682         }
2683       else if (!noconvert)
2684         arg = default_conversion (arg);
2685       arg = non_lvalue (arg);
2686       break;
2687
2688     case NEGATE_EXPR:
2689       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2690             || typecode == COMPLEX_TYPE
2691             || typecode == VECTOR_TYPE))
2692         {
2693           error ("wrong type argument to unary minus");
2694           return error_mark_node;
2695         }
2696       else if (!noconvert)
2697         arg = default_conversion (arg);
2698       break;
2699
2700     case BIT_NOT_EXPR:
2701       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2702         {
2703           if (!noconvert)
2704             arg = default_conversion (arg);
2705         }
2706       else if (typecode == COMPLEX_TYPE)
2707         {
2708           code = CONJ_EXPR;
2709           if (pedantic)
2710             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2711           if (!noconvert)
2712             arg = default_conversion (arg);
2713         }
2714       else
2715         {
2716           error ("wrong type argument to bit-complement");
2717           return error_mark_node;
2718         }
2719       break;
2720
2721     case ABS_EXPR:
2722       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2723         {
2724           error ("wrong type argument to abs");
2725           return error_mark_node;
2726         }
2727       else if (!noconvert)
2728         arg = default_conversion (arg);
2729       break;
2730
2731     case CONJ_EXPR:
2732       /* Conjugating a real value is a no-op, but allow it anyway.  */
2733       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2734             || typecode == COMPLEX_TYPE))
2735         {
2736           error ("wrong type argument to conjugation");
2737           return error_mark_node;
2738         }
2739       else if (!noconvert)
2740         arg = default_conversion (arg);
2741       break;
2742
2743     case TRUTH_NOT_EXPR:
2744       if (typecode != INTEGER_TYPE
2745           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2746           && typecode != COMPLEX_TYPE)
2747         {
2748           error ("wrong type argument to unary exclamation mark");
2749           return error_mark_node;
2750         }
2751       arg = c_objc_common_truthvalue_conversion (arg);
2752       return invert_truthvalue (arg);
2753
2754     case NOP_EXPR:
2755       break;
2756
2757     case REALPART_EXPR:
2758       if (TREE_CODE (arg) == COMPLEX_CST)
2759         return TREE_REALPART (arg);
2760       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2761         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2762       else
2763         return arg;
2764
2765     case IMAGPART_EXPR:
2766       if (TREE_CODE (arg) == COMPLEX_CST)
2767         return TREE_IMAGPART (arg);
2768       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2769         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2770       else
2771         return convert (TREE_TYPE (arg), integer_zero_node);
2772
2773     case PREINCREMENT_EXPR:
2774     case POSTINCREMENT_EXPR:
2775     case PREDECREMENT_EXPR:
2776     case POSTDECREMENT_EXPR:
2777
2778       /* Increment or decrement the real part of the value,
2779          and don't change the imaginary part.  */
2780       if (typecode == COMPLEX_TYPE)
2781         {
2782           tree real, imag;
2783
2784           if (pedantic)
2785             pedwarn ("ISO C does not support %<++%> and %<--%>"
2786                      " on complex types");
2787
2788           arg = stabilize_reference (arg);
2789           real = build_unary_op (REALPART_EXPR, arg, 1);
2790           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2791           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2792                          build_unary_op (code, real, 1), imag);
2793         }
2794
2795       /* Report invalid types.  */
2796
2797       if (typecode != POINTER_TYPE
2798           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2799         {
2800           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2801             error ("wrong type argument to increment");
2802           else
2803             error ("wrong type argument to decrement");
2804
2805           return error_mark_node;
2806         }
2807
2808       {
2809         tree inc;
2810         tree result_type = TREE_TYPE (arg);
2811
2812         arg = get_unwidened (arg, 0);
2813         argtype = TREE_TYPE (arg);
2814
2815         /* Compute the increment.  */
2816
2817         if (typecode == POINTER_TYPE)
2818           {
2819             /* If pointer target is an undefined struct,
2820                we just cannot know how to do the arithmetic.  */
2821             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2822               {
2823                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2824                   error ("increment of pointer to unknown structure");
2825                 else
2826                   error ("decrement of pointer to unknown structure");
2827               }
2828             else if ((pedantic || warn_pointer_arith)
2829                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2830                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2831               {
2832                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2833                   pedwarn ("wrong type argument to increment");
2834                 else
2835                   pedwarn ("wrong type argument to decrement");
2836               }
2837
2838             inc = c_size_in_bytes (TREE_TYPE (result_type));
2839           }
2840         else
2841           inc = integer_one_node;
2842
2843         inc = convert (argtype, inc);
2844
2845         /* Complain about anything else that is not a true lvalue.  */
2846         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2847                                     || code == POSTINCREMENT_EXPR)
2848                                    ? lv_increment
2849                                    : lv_decrement)))
2850           return error_mark_node;
2851
2852         /* Report a read-only lvalue.  */
2853         if (TREE_READONLY (arg))
2854           readonly_error (arg,
2855                           ((code == PREINCREMENT_EXPR
2856                             || code == POSTINCREMENT_EXPR)
2857                            ? lv_increment : lv_decrement));
2858
2859         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2860           val = boolean_increment (code, arg);
2861         else
2862           val = build2 (code, TREE_TYPE (arg), arg, inc);
2863         TREE_SIDE_EFFECTS (val) = 1;
2864         val = convert (result_type, val);
2865         if (TREE_CODE (val) != code)
2866           TREE_NO_WARNING (val) = 1;
2867         return val;
2868       }
2869
2870     case ADDR_EXPR:
2871       /* Note that this operation never does default_conversion.  */
2872
2873       /* Let &* cancel out to simplify resulting code.  */
2874       if (TREE_CODE (arg) == INDIRECT_REF)
2875         {
2876           /* Don't let this be an lvalue.  */
2877           if (lvalue_p (TREE_OPERAND (arg, 0)))
2878             return non_lvalue (TREE_OPERAND (arg, 0));
2879           return TREE_OPERAND (arg, 0);
2880         }
2881
2882       /* For &x[y], return x+y */
2883       if (TREE_CODE (arg) == ARRAY_REF)
2884         {
2885           tree op0 = TREE_OPERAND (arg, 0);
2886           if (!c_mark_addressable (op0))
2887             return error_mark_node;
2888           return build_binary_op (PLUS_EXPR,
2889                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2890                                    ? array_to_pointer_conversion (op0)
2891                                    : op0),
2892                                   TREE_OPERAND (arg, 1), 1);
2893         }
2894
2895       /* Anything not already handled and not a true memory reference
2896          or a non-lvalue array is an error.  */
2897       else if (typecode != FUNCTION_TYPE && !flag
2898                && !lvalue_or_else (arg, lv_addressof))
2899         return error_mark_node;
2900
2901       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2902       argtype = TREE_TYPE (arg);
2903
2904       /* If the lvalue is const or volatile, merge that into the type
2905          to which the address will point.  Note that you can't get a
2906          restricted pointer by taking the address of something, so we
2907          only have to deal with `const' and `volatile' here.  */
2908       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2909           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2910           argtype = c_build_type_variant (argtype,
2911                                           TREE_READONLY (arg),
2912                                           TREE_THIS_VOLATILE (arg));
2913
2914       if (!c_mark_addressable (arg))
2915         return error_mark_node;
2916
2917       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2918                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2919
2920       argtype = build_pointer_type (argtype);
2921
2922       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2923          when we have proper support for integer constant expressions.  */
2924       val = get_base_address (arg);
2925       if (val && TREE_CODE (val) == INDIRECT_REF
2926           && integer_zerop (TREE_OPERAND (val, 0)))
2927         return fold_convert (argtype, fold_offsetof (arg));
2928
2929       val = build1 (ADDR_EXPR, argtype, arg);
2930
2931       return val;
2932
2933     default:
2934       break;
2935     }
2936
2937   if (argtype == 0)
2938     argtype = TREE_TYPE (arg);
2939   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
2940                                 : fold_build1 (code, argtype, arg);
2941 }
2942
2943 /* Return nonzero if REF is an lvalue valid for this language.
2944    Lvalues can be assigned, unless their type has TYPE_READONLY.
2945    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2946
2947 static int
2948 lvalue_p (tree ref)
2949 {
2950   enum tree_code code = TREE_CODE (ref);
2951
2952   switch (code)
2953     {
2954     case REALPART_EXPR:
2955     case IMAGPART_EXPR:
2956     case COMPONENT_REF:
2957       return lvalue_p (TREE_OPERAND (ref, 0));
2958
2959     case COMPOUND_LITERAL_EXPR:
2960     case STRING_CST:
2961       return 1;
2962
2963     case INDIRECT_REF:
2964     case ARRAY_REF:
2965     case VAR_DECL:
2966     case PARM_DECL:
2967     case RESULT_DECL:
2968     case ERROR_MARK:
2969       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2970               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2971
2972     case BIND_EXPR:
2973       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2974
2975     default:
2976       return 0;
2977     }
2978 }
2979 \f
2980 /* Give an error for storing in something that is 'const'.  */
2981
2982 static void
2983 readonly_error (tree arg, enum lvalue_use use)
2984 {
2985   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
2986               || use == lv_asm);
2987   /* Using this macro rather than (for example) arrays of messages
2988      ensures that all the format strings are checked at compile
2989      time.  */
2990 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
2991                                    : (use == lv_increment ? (I)         \
2992                                    : (use == lv_decrement ? (D) : (AS))))
2993   if (TREE_CODE (arg) == COMPONENT_REF)
2994     {
2995       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
2996         readonly_error (TREE_OPERAND (arg, 0), use);
2997       else
2998         error (READONLY_MSG (G_("assignment of read-only member %qD"),
2999                              G_("increment of read-only member %qD"),
3000                              G_("decrement of read-only member %qD"),
3001                              G_("read-only member %qD used as %<asm%> output")),
3002                TREE_OPERAND (arg, 1));
3003     }
3004   else if (TREE_CODE (arg) == VAR_DECL)
3005     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3006                          G_("increment of read-only variable %qD"),
3007                          G_("decrement of read-only variable %qD"),
3008                          G_("read-only variable %qD used as %<asm%> output")),
3009            arg);
3010   else
3011     error (READONLY_MSG (G_("assignment of read-only location"),
3012                          G_("increment of read-only location"),
3013                          G_("decrement of read-only location"),
3014                          G_("read-only location used as %<asm%> output")));
3015 }
3016
3017
3018 /* Return nonzero if REF is an lvalue valid for this language;
3019    otherwise, print an error message and return zero.  USE says
3020    how the lvalue is being used and so selects the error message.  */
3021
3022 static int
3023 lvalue_or_else (tree ref, enum lvalue_use use)
3024 {
3025   int win = lvalue_p (ref);
3026
3027   if (!win)
3028     lvalue_error (use);
3029
3030   return win;
3031 }
3032 \f
3033 /* Mark EXP saying that we need to be able to take the
3034    address of it; it should not be allocated in a register.
3035    Returns true if successful.  */
3036
3037 bool
3038 c_mark_addressable (tree exp)
3039 {
3040   tree x = exp;
3041
3042   while (1)
3043     switch (TREE_CODE (x))
3044       {
3045       case COMPONENT_REF:
3046         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3047           {
3048             error
3049               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3050             return false;
3051           }
3052
3053         /* ... fall through ...  */
3054
3055       case ADDR_EXPR:
3056       case ARRAY_REF:
3057       case REALPART_EXPR:
3058       case IMAGPART_EXPR:
3059         x = TREE_OPERAND (x, 0);
3060         break;
3061
3062       case COMPOUND_LITERAL_EXPR:
3063       case CONSTRUCTOR:
3064         TREE_ADDRESSABLE (x) = 1;
3065         return true;
3066
3067       case VAR_DECL:
3068       case CONST_DECL:
3069       case PARM_DECL:
3070       case RESULT_DECL:
3071         if (C_DECL_REGISTER (x)
3072             && DECL_NONLOCAL (x))
3073           {
3074             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3075               {
3076                 error
3077                   ("global register variable %qD used in nested function", x);
3078                 return false;
3079               }
3080             pedwarn ("register variable %qD used in nested function", x);
3081           }
3082         else if (C_DECL_REGISTER (x))
3083           {
3084             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3085               error ("address of global register variable %qD requested", x);
3086             else
3087               error ("address of register variable %qD requested", x);
3088             return false;
3089           }
3090
3091         /* drops in */
3092       case FUNCTION_DECL:
3093         TREE_ADDRESSABLE (x) = 1;
3094         /* drops out */
3095       default:
3096         return true;
3097     }
3098 }
3099 \f
3100 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3101
3102 tree
3103 build_conditional_expr (tree ifexp, tree op1, tree op2)
3104 {
3105   tree type1;
3106   tree type2;
3107   enum tree_code code1;
3108   enum tree_code code2;
3109   tree result_type = NULL;
3110   tree orig_op1 = op1, orig_op2 = op2;
3111
3112   /* Promote both alternatives.  */
3113
3114   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3115     op1 = default_conversion (op1);
3116   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3117     op2 = default_conversion (op2);
3118
3119   if (TREE_CODE (ifexp) == ERROR_MARK
3120       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3121       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3122     return error_mark_node;
3123
3124   type1 = TREE_TYPE (op1);
3125   code1 = TREE_CODE (type1);
3126   type2 = TREE_TYPE (op2);
3127   code2 = TREE_CODE (type2);
3128
3129   /* C90 does not permit non-lvalue arrays in conditional expressions.
3130      In C99 they will be pointers by now.  */
3131   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3132     {
3133       error ("non-lvalue array in conditional expression");
3134       return error_mark_node;
3135     }
3136
3137   /* Quickly detect the usual case where op1 and op2 have the same type
3138      after promotion.  */
3139   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3140     {
3141       if (type1 == type2)
3142         result_type = type1;
3143       else
3144         result_type = TYPE_MAIN_VARIANT (type1);
3145     }
3146   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3147             || code1 == COMPLEX_TYPE)
3148            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3149                || code2 == COMPLEX_TYPE))
3150     {
3151       result_type = c_common_type (type1, type2);
3152
3153       /* If -Wsign-compare, warn here if type1 and type2 have
3154          different signedness.  We'll promote the signed to unsigned
3155          and later code won't know it used to be different.
3156          Do this check on the original types, so that explicit casts
3157          will be considered, but default promotions won't.  */
3158       if (warn_sign_compare && !skip_evaluation)
3159         {
3160           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3161           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3162
3163           if (unsigned_op1 ^ unsigned_op2)
3164             {
3165               /* Do not warn if the result type is signed, since the
3166                  signed type will only be chosen if it can represent
3167                  all the values of the unsigned type.  */
3168               if (!TYPE_UNSIGNED (result_type))
3169                 /* OK */;
3170               /* Do not warn if the signed quantity is an unsuffixed
3171                  integer literal (or some static constant expression
3172                  involving such literals) and it is non-negative.  */
3173               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3174                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3175                 /* OK */;
3176               else
3177                 warning (0, "signed and unsigned type in conditional expression");
3178             }
3179         }
3180     }
3181   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3182     {
3183       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3184         pedwarn ("ISO C forbids conditional expr with only one void side");
3185       result_type = void_type_node;
3186     }
3187   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3188     {
3189       if (comp_target_types (type1, type2))
3190         result_type = common_pointer_type (type1, type2);
3191       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3192                && TREE_CODE (orig_op1) != NOP_EXPR)
3193         result_type = qualify_type (type2, type1);
3194       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3195                && TREE_CODE (orig_op2) != NOP_EXPR)
3196         result_type = qualify_type (type1, type2);
3197       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3198         {
3199           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3200             pedwarn ("ISO C forbids conditional expr between "
3201                      "%<void *%> and function pointer");
3202           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3203                                                           TREE_TYPE (type2)));
3204         }
3205       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3206         {
3207           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3208             pedwarn ("ISO C forbids conditional expr between "
3209                      "%<void *%> and function pointer");
3210           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3211                                                           TREE_TYPE (type1)));
3212         }
3213       else
3214         {
3215           pedwarn ("pointer type mismatch in conditional expression");
3216           result_type = build_pointer_type (void_type_node);
3217         }
3218     }
3219   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3220     {
3221       if (!integer_zerop (op2))
3222         pedwarn ("pointer/integer type mismatch in conditional expression");
3223       else
3224         {
3225           op2 = null_pointer_node;
3226         }
3227       result_type = type1;
3228     }
3229   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3230     {
3231       if (!integer_zerop (op1))
3232         pedwarn ("pointer/integer type mismatch in conditional expression");
3233       else
3234         {
3235           op1 = null_pointer_node;
3236         }
3237       result_type = type2;
3238     }
3239
3240   if (!result_type)
3241     {
3242       if (flag_cond_mismatch)
3243         result_type = void_type_node;
3244       else
3245         {
3246           error ("type mismatch in conditional expression");
3247           return error_mark_node;
3248         }
3249     }
3250
3251   /* Merge const and volatile flags of the incoming types.  */
3252   result_type
3253     = build_type_variant (result_type,
3254                           TREE_READONLY (op1) || TREE_READONLY (op2),
3255                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3256
3257   if (result_type != TREE_TYPE (op1))
3258     op1 = convert_and_check (result_type, op1);
3259   if (result_type != TREE_TYPE (op2))
3260     op2 = convert_and_check (result_type, op2);
3261
3262   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3263 }
3264 \f
3265 /* Return a compound expression that performs two expressions and
3266    returns the value of the second of them.  */
3267
3268 tree
3269 build_compound_expr (tree expr1, tree expr2)
3270 {
3271   if (!TREE_SIDE_EFFECTS (expr1))
3272     {
3273       /* The left-hand operand of a comma expression is like an expression
3274          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3275          any side-effects, unless it was explicitly cast to (void).  */
3276       if (warn_unused_value)
3277         {
3278           if (VOID_TYPE_P (TREE_TYPE (expr1))
3279               && TREE_CODE (expr1) == CONVERT_EXPR)
3280             ; /* (void) a, b */
3281           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3282                    && TREE_CODE (expr1) == COMPOUND_EXPR
3283                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3284             ; /* (void) a, (void) b, c */
3285           else
3286             warning (0, "left-hand operand of comma expression has no effect");
3287         }
3288     }
3289
3290   /* With -Wunused, we should also warn if the left-hand operand does have
3291      side-effects, but computes a value which is not used.  For example, in
3292      `foo() + bar(), baz()' the result of the `+' operator is not used,
3293      so we should issue a warning.  */
3294   else if (warn_unused_value)
3295     warn_if_unused_value (expr1, input_location);
3296
3297   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3298 }
3299
3300 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3301
3302 tree
3303 build_c_cast (tree type, tree expr)
3304 {
3305   tree value = expr;
3306
3307   if (type == error_mark_node || expr == error_mark_node)
3308     return error_mark_node;
3309
3310   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3311      only in <protocol> qualifications.  But when constructing cast expressions,
3312      the protocols do matter and must be kept around.  */
3313   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3314     return build1 (NOP_EXPR, type, expr);
3315
3316   type = TYPE_MAIN_VARIANT (type);
3317
3318   if (TREE_CODE (type) == ARRAY_TYPE)
3319     {
3320       error ("cast specifies array type");
3321       return error_mark_node;
3322     }
3323
3324   if (TREE_CODE (type) == FUNCTION_TYPE)
3325     {
3326       error ("cast specifies function type");
3327       return error_mark_node;
3328     }
3329
3330   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3331     {
3332       if (pedantic)
3333         {
3334           if (TREE_CODE (type) == RECORD_TYPE
3335               || TREE_CODE (type) == UNION_TYPE)
3336             pedwarn ("ISO C forbids casting nonscalar to the same type");
3337         }
3338     }
3339   else if (TREE_CODE (type) == UNION_TYPE)
3340     {
3341       tree field;
3342
3343       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3344         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3345                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3346           break;
3347
3348       if (field)
3349         {
3350           tree t;
3351
3352           if (pedantic)
3353             pedwarn ("ISO C forbids casts to union type");
3354           t = digest_init (type,
3355                            build_constructor_single (type, field, value),
3356                            true, 0);
3357           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3358           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3359           return t;
3360         }
3361       error ("cast to union type from type not present in union");
3362       return error_mark_node;
3363     }
3364   else
3365     {
3366       tree otype, ovalue;
3367
3368       if (type == void_type_node)
3369         return build1 (CONVERT_EXPR, type, value);
3370
3371       otype = TREE_TYPE (value);
3372
3373       /* Optionally warn about potentially worrisome casts.  */
3374
3375       if (warn_cast_qual
3376           && TREE_CODE (type) == POINTER_TYPE
3377           && TREE_CODE (otype) == POINTER_TYPE)
3378         {
3379           tree in_type = type;
3380           tree in_otype = otype;
3381           int added = 0;
3382           int discarded = 0;
3383
3384           /* Check that the qualifiers on IN_TYPE are a superset of
3385              the qualifiers of IN_OTYPE.  The outermost level of
3386              POINTER_TYPE nodes is uninteresting and we stop as soon
3387              as we hit a non-POINTER_TYPE node on either type.  */
3388           do
3389             {
3390               in_otype = TREE_TYPE (in_otype);
3391               in_type = TREE_TYPE (in_type);
3392
3393               /* GNU C allows cv-qualified function types.  'const'
3394                  means the function is very pure, 'volatile' means it
3395                  can't return.  We need to warn when such qualifiers
3396                  are added, not when they're taken away.  */
3397               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3398                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3399                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3400               else
3401                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3402             }
3403           while (TREE_CODE (in_type) == POINTER_TYPE
3404                  && TREE_CODE (in_otype) == POINTER_TYPE);
3405
3406           if (added)
3407             warning (0, "cast adds new qualifiers to function type");
3408
3409           if (discarded)
3410             /* There are qualifiers present in IN_OTYPE that are not
3411                present in IN_TYPE.  */
3412             warning (0, "cast discards qualifiers from pointer target type");
3413         }
3414
3415       /* Warn about possible alignment problems.  */
3416       if (STRICT_ALIGNMENT
3417           && TREE_CODE (type) == POINTER_TYPE
3418           && TREE_CODE (otype) == POINTER_TYPE
3419           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3420           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3421           /* Don't warn about opaque types, where the actual alignment
3422              restriction is unknown.  */
3423           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3424                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3425                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3426           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3427         warning (OPT_Wcast_align,
3428                  "cast increases required alignment of target type");
3429
3430       if (TREE_CODE (type) == INTEGER_TYPE
3431           && TREE_CODE (otype) == POINTER_TYPE
3432           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3433           && !TREE_CONSTANT (value))
3434         warning (OPT_Wpointer_to_int_cast,
3435                  "cast from pointer to integer of different size");
3436
3437       if (TREE_CODE (value) == CALL_EXPR
3438           && TREE_CODE (type) != TREE_CODE (otype))
3439         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3440                  "to non-matching type %qT", otype, type);
3441
3442       if (TREE_CODE (type) == POINTER_TYPE
3443           && TREE_CODE (otype) == INTEGER_TYPE
3444           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3445           /* Don't warn about converting any constant.  */
3446           && !TREE_CONSTANT (value))
3447         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3448                  "of different size");
3449
3450       if (flag_strict_aliasing && warn_strict_aliasing
3451           && TREE_CODE (type) == POINTER_TYPE
3452           && TREE_CODE (otype) == POINTER_TYPE
3453           && TREE_CODE (expr) == ADDR_EXPR
3454           && (DECL_P (TREE_OPERAND (expr, 0))
3455               || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
3456           && !VOID_TYPE_P (TREE_TYPE (type)))
3457         {
3458           /* Casting the address of an object to non void pointer. Warn
3459              if the cast breaks type based aliasing.  */
3460           if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
3461             warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
3462                      "might break strict-aliasing rules");
3463           else
3464             {
3465               HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
3466               HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
3467
3468               if (!alias_sets_conflict_p (set1, set2))
3469                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3470                          "pointer will break strict-aliasing rules");
3471               else if (warn_strict_aliasing > 1
3472                        && !alias_sets_might_conflict_p (set1, set2))
3473                 warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
3474                          "pointer might break strict-aliasing rules");
3475             }
3476         }
3477
3478       /* If pedantic, warn for conversions between function and object
3479          pointer types, except for converting a null pointer constant
3480          to function pointer type.  */
3481       if (pedantic
3482           && TREE_CODE (type) == POINTER_TYPE
3483           && TREE_CODE (otype) == POINTER_TYPE
3484           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3485           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3486         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3487
3488       if (pedantic
3489           && TREE_CODE (type) == POINTER_TYPE
3490           && TREE_CODE (otype) == POINTER_TYPE
3491           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3492           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3493           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3494                && TREE_CODE (expr) != NOP_EXPR))
3495         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3496
3497       ovalue = value;
3498       value = convert (type, value);
3499
3500       /* Ignore any integer overflow caused by the cast.  */
3501       if (TREE_CODE (value) == INTEGER_CST)
3502         {
3503           /* If OVALUE had overflow set, then so will VALUE, so it
3504              is safe to overwrite.  */
3505           if (CONSTANT_CLASS_P (ovalue))
3506             {
3507               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3508               /* Similarly, constant_overflow cannot have become cleared.  */
3509               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3510             }
3511           else
3512             TREE_OVERFLOW (value) = 0;
3513         }
3514     }
3515
3516   /* Don't let a cast be an lvalue.  */
3517   if (value == expr)
3518     value = non_lvalue (value);
3519
3520   return value;
3521 }
3522
3523 /* Interpret a cast of expression EXPR to type TYPE.  */
3524 tree
3525 c_cast_expr (struct c_type_name *type_name, tree expr)
3526 {
3527   tree type;
3528   int saved_wsp = warn_strict_prototypes;
3529
3530   /* This avoids warnings about unprototyped casts on
3531      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3532   if (TREE_CODE (expr) == INTEGER_CST)
3533     warn_strict_prototypes = 0;
3534   type = groktypename (type_name);
3535   warn_strict_prototypes = saved_wsp;
3536
3537   return build_c_cast (type, expr);
3538 }
3539
3540 \f
3541 /* Build an assignment expression of lvalue LHS from value RHS.
3542    MODIFYCODE is the code for a binary operator that we use
3543    to combine the old value of LHS with RHS to get the new value.
3544    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3545
3546 tree
3547 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3548 {
3549   tree result;
3550   tree newrhs;
3551   tree lhstype = TREE_TYPE (lhs);
3552   tree olhstype = lhstype;
3553
3554   /* Types that aren't fully specified cannot be used in assignments.  */
3555   lhs = require_complete_type (lhs);
3556
3557   /* Avoid duplicate error messages from operands that had errors.  */
3558   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3559     return error_mark_node;
3560
3561   STRIP_TYPE_NOPS (rhs);
3562
3563   newrhs = rhs;
3564
3565   /* If a binary op has been requested, combine the old LHS value with the RHS
3566      producing the value we should actually store into the LHS.  */
3567
3568   if (modifycode != NOP_EXPR)
3569     {
3570       lhs = stabilize_reference (lhs);
3571       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3572     }
3573
3574   if (!lvalue_or_else (lhs, lv_assign))
3575     return error_mark_node;
3576
3577   /* Give an error for storing in something that is 'const'.  */
3578
3579   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3580       || ((TREE_CODE (lhstype) == RECORD_TYPE
3581            || TREE_CODE (lhstype) == UNION_TYPE)
3582           && C_TYPE_FIELDS_READONLY (lhstype)))
3583     readonly_error (lhs, lv_assign);
3584
3585   /* If storing into a structure or union member,
3586      it has probably been given type `int'.
3587      Compute the type that would go with
3588      the actual amount of storage the member occupies.  */
3589
3590   if (TREE_CODE (lhs) == COMPONENT_REF
3591       && (TREE_CODE (lhstype) == INTEGER_TYPE
3592           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3593           || TREE_CODE (lhstype) == REAL_TYPE
3594           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3595     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3596
3597   /* If storing in a field that is in actuality a short or narrower than one,
3598      we must store in the field in its actual type.  */
3599
3600   if (lhstype != TREE_TYPE (lhs))
3601     {
3602       lhs = copy_node (lhs);
3603       TREE_TYPE (lhs) = lhstype;
3604     }
3605
3606   /* Convert new value to destination type.  */
3607
3608   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3609                                    NULL_TREE, NULL_TREE, 0);
3610   if (TREE_CODE (newrhs) == ERROR_MARK)
3611     return error_mark_node;
3612
3613   /* Emit ObjC write barrier, if necessary.  */
3614   if (c_dialect_objc () && flag_objc_gc)
3615     {
3616       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3617       if (result)
3618         return result;
3619     }
3620
3621   /* Scan operands.  */
3622
3623   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3624   TREE_SIDE_EFFECTS (result) = 1;
3625
3626   /* If we got the LHS in a different type for storing in,
3627      convert the result back to the nominal type of LHS
3628      so that the value we return always has the same type
3629      as the LHS argument.  */
3630
3631   if (olhstype == TREE_TYPE (result))
3632     return result;
3633   return convert_for_assignment (olhstype, result, ic_assign,
3634                                  NULL_TREE, NULL_TREE, 0);
3635 }
3636 \f
3637 /* Convert value RHS to type TYPE as preparation for an assignment
3638    to an lvalue of type TYPE.
3639    The real work of conversion is done by `convert'.
3640    The purpose of this function is to generate error messages
3641    for assignments that are not allowed in C.
3642    ERRTYPE says whether it is argument passing, assignment,
3643    initialization or return.
3644
3645    FUNCTION is a tree for the function being called.
3646    PARMNUM is the number of the argument, for printing in error messages.  */
3647
3648 static tree
3649 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3650                         tree fundecl, tree function, int parmnum)
3651 {
3652   enum tree_code codel = TREE_CODE (type);
3653   tree rhstype;
3654   enum tree_code coder;
3655   tree rname = NULL_TREE;
3656   bool objc_ok = false;
3657
3658   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3659     {
3660       tree selector;
3661       /* Change pointer to function to the function itself for
3662          diagnostics.  */
3663       if (TREE_CODE (function) == ADDR_EXPR
3664           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3665         function = TREE_OPERAND (function, 0);
3666
3667       /* Handle an ObjC selector specially for diagnostics.  */
3668       selector = objc_message_selector ();
3669       rname = function;
3670       if (selector && parmnum > 2)
3671         {
3672           rname = selector;
3673           parmnum -= 2;
3674         }
3675     }
3676
3677   /* This macro is used to emit diagnostics to ensure that all format
3678      strings are complete sentences, visible to gettext and checked at
3679      compile time.  */
3680 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3681   do {                                          \
3682     switch (errtype)                            \
3683       {                                         \
3684       case ic_argpass:                          \
3685         pedwarn (AR, parmnum, rname);           \
3686         break;                                  \
3687       case ic_argpass_nonproto:                 \
3688         warning (0, AR, parmnum, rname);                \
3689         break;                                  \
3690       case ic_assign:                           \
3691         pedwarn (AS);                           \
3692         break;                                  \
3693       case ic_init:                             \
3694         pedwarn (IN);                           \
3695         break;                                  \
3696       case ic_return:                           \
3697         pedwarn (RE);                           \
3698         break;                                  \
3699       default:                                  \
3700         gcc_unreachable ();                     \
3701       }                                         \
3702   } while (0)
3703
3704   STRIP_TYPE_NOPS (rhs);
3705
3706   if (optimize && TREE_CODE (rhs) == VAR_DECL
3707            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3708     rhs = decl_constant_value_for_broken_optimization (rhs);
3709
3710   rhstype = TREE_TYPE (rhs);
3711   coder = TREE_CODE (rhstype);
3712
3713   if (coder == ERROR_MARK)
3714     return error_mark_node;
3715
3716   if (c_dialect_objc ())
3717     {
3718       int parmno;
3719
3720       switch (errtype)
3721         {
3722         case ic_return:
3723           parmno = 0;
3724           break;
3725
3726         case ic_assign:
3727           parmno = -1;
3728           break;
3729
3730         case ic_init:
3731           parmno = -2;
3732           break;
3733
3734         default:
3735           parmno = parmnum;
3736           break;
3737         }
3738
3739       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3740     }
3741
3742   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3743     {
3744       overflow_warning (rhs);
3745       return rhs;
3746     }
3747
3748   if (coder == VOID_TYPE)
3749     {
3750       /* Except for passing an argument to an unprototyped function,
3751          this is a constraint violation.  When passing an argument to
3752          an unprototyped function, it is compile-time undefined;
3753          making it a constraint in that case was rejected in
3754          DR#252.  */
3755       error ("void value not ignored as it ought to be");
3756       return error_mark_node;
3757     }
3758   /* A type converts to a reference to it.
3759      This code doesn't fully support references, it's just for the
3760      special case of va_start and va_copy.  */
3761   if (codel == REFERENCE_TYPE
3762       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3763     {
3764       if (!lvalue_p (rhs))
3765         {
3766           error ("cannot pass rvalue to reference parameter");
3767           return error_mark_node;
3768         }
3769       if (!c_mark_addressable (rhs))
3770         return error_mark_node;
3771       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3772
3773       /* We already know that these two types are compatible, but they
3774          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3775          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3776          likely to be va_list, a typedef to __builtin_va_list, which
3777          is different enough that it will cause problems later.  */
3778       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3779         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3780
3781       rhs = build1 (NOP_EXPR, type, rhs);
3782       return rhs;
3783     }
3784   /* Some types can interconvert without explicit casts.  */
3785   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3786            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3787     return convert (type, rhs);
3788   /* Arithmetic types all interconvert, and enum is treated like int.  */
3789   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3790             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3791             || codel == BOOLEAN_TYPE)
3792            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3793                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3794                || coder == BOOLEAN_TYPE))
3795     return convert_and_check (type, rhs);
3796
3797   /* Conversion to a transparent union from its member types.
3798      This applies only to function arguments.  */
3799   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3800            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3801     {
3802       tree memb, marginal_memb = NULL_TREE;
3803
3804       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3805         {
3806           tree memb_type = TREE_TYPE (memb);
3807
3808           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3809                          TYPE_MAIN_VARIANT (rhstype)))
3810             break;
3811
3812           if (TREE_CODE (memb_type) != POINTER_TYPE)
3813             continue;
3814
3815           if (coder == POINTER_TYPE)
3816             {
3817               tree ttl = TREE_TYPE (memb_type);
3818               tree ttr = TREE_TYPE (rhstype);
3819
3820               /* Any non-function converts to a [const][volatile] void *
3821                  and vice versa; otherwise, targets must be the same.
3822                  Meanwhile, the lhs target must have all the qualifiers of
3823                  the rhs.  */
3824               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3825                   || comp_target_types (memb_type, rhstype))
3826                 {
3827                   /* If this type won't generate any warnings, use it.  */
3828                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3829                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3830                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3831                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3832                              == TYPE_QUALS (ttr))
3833                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3834                              == TYPE_QUALS (ttl))))
3835                     break;
3836
3837                   /* Keep looking for a better type, but remember this one.  */
3838                   if (!marginal_memb)
3839                     marginal_memb = memb;
3840                 }
3841             }
3842
3843           /* Can convert integer zero to any pointer type.  */
3844           if (integer_zerop (rhs)
3845               || (TREE_CODE (rhs) == NOP_EXPR
3846                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3847             {
3848               rhs = null_pointer_node;
3849               break;
3850             }
3851         }
3852
3853       if (memb || marginal_memb)
3854         {
3855           if (!memb)
3856             {
3857               /* We have only a marginally acceptable member type;
3858                  it needs a warning.  */
3859               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3860               tree ttr = TREE_TYPE (rhstype);
3861
3862               /* Const and volatile mean something different for function
3863                  types, so the usual warnings are not appropriate.  */
3864               if (TREE_CODE (ttr) == FUNCTION_TYPE
3865                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3866                 {
3867                   /* Because const and volatile on functions are
3868                      restrictions that say the function will not do
3869                      certain things, it is okay to use a const or volatile
3870                      function where an ordinary one is wanted, but not
3871                      vice-versa.  */
3872                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3873                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3874                                             "makes qualified function "
3875                                             "pointer from unqualified"),
3876                                          G_("assignment makes qualified "
3877                                             "function pointer from "
3878                                             "unqualified"),
3879                                          G_("initialization makes qualified "
3880                                             "function pointer from "
3881                                             "unqualified"),
3882                                          G_("return makes qualified function "
3883                                             "pointer from unqualified"));
3884                 }
3885               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3886                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3887                                         "qualifiers from pointer target type"),
3888                                      G_("assignment discards qualifiers "
3889                                         "from pointer target type"),
3890                                      G_("initialization discards qualifiers "
3891                                         "from pointer target type"),
3892                                      G_("return discards qualifiers from "
3893                                         "pointer target type"));
3894
3895               memb = marginal_memb;
3896             }
3897
3898           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3899             pedwarn ("ISO C prohibits argument conversion to union type");
3900
3901           return build_constructor_single (type, memb, rhs);
3902         }
3903     }
3904
3905   /* Conversions among pointers */
3906   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3907            && (coder == codel))
3908     {
3909       tree ttl = TREE_TYPE (type);
3910       tree ttr = TREE_TYPE (rhstype);
3911       tree mvl = ttl;
3912       tree mvr = ttr;
3913       bool is_opaque_pointer;
3914       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3915
3916       if (TREE_CODE (mvl) != ARRAY_TYPE)
3917         mvl = TYPE_MAIN_VARIANT (mvl);
3918       if (TREE_CODE (mvr) != ARRAY_TYPE)
3919         mvr = TYPE_MAIN_VARIANT (mvr);
3920       /* Opaque pointers are treated like void pointers.  */
3921       is_opaque_pointer = (targetm.vector_opaque_p (type)
3922                            || targetm.vector_opaque_p (rhstype))
3923         && TREE_CODE (ttl) == VECTOR_TYPE
3924         && TREE_CODE (ttr) == VECTOR_TYPE;
3925
3926       /* C++ does not allow the implicit conversion void* -> T*.  However,
3927          for the purpose of reducing the number of false positives, we
3928          tolerate the special case of
3929
3930                 int *p = NULL;
3931
3932          where NULL is typically defined in C to be '(void *) 0'.  */
3933       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3934         warning (OPT_Wc___compat, "request for implicit conversion from "
3935                  "%qT to %qT not permitted in C++", rhstype, type);
3936
3937       /* Check if the right-hand side has a format attribute but the
3938          left-hand side doesn't.  */
3939       if (warn_missing_format_attribute
3940           && check_missing_format_attribute (type, rhstype))
3941         {
3942           switch (errtype)
3943           {
3944           case ic_argpass:
3945           case ic_argpass_nonproto:
3946             warning (OPT_Wmissing_format_attribute,
3947                      "argument %d of %qE might be "
3948                      "a candidate for a format attribute",
3949                      parmnum, rname);
3950             break;
3951           case ic_assign:
3952             warning (OPT_Wmissing_format_attribute,
3953                      "assignment left-hand side might be "
3954                      "a candidate for a format attribute");
3955             break;
3956           case ic_init:
3957             warning (OPT_Wmissing_format_attribute,
3958                      "initialization left-hand side might be "
3959                      "a candidate for a format attribute");
3960             break;
3961           case ic_return:
3962             warning (OPT_Wmissing_format_attribute,
3963                      "return type might be "
3964                      "a candidate for a format attribute");
3965             break;
3966           default:
3967             gcc_unreachable ();
3968           }
3969         }
3970
3971       /* Any non-function converts to a [const][volatile] void *
3972          and vice versa; otherwise, targets must be the same.
3973          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3974       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3975           || (target_cmp = comp_target_types (type, rhstype))
3976           || is_opaque_pointer
3977           || (c_common_unsigned_type (mvl)
3978               == c_common_unsigned_type (mvr)))
3979         {
3980           if (pedantic
3981               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3982                   ||
3983                   (VOID_TYPE_P (ttr)
3984                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3985                       which are not ANSI null ptr constants.  */
3986                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3987                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3988             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3989                                     "%qE between function pointer "
3990                                     "and %<void *%>"),
3991                                  G_("ISO C forbids assignment between "
3992                                     "function pointer and %<void *%>"),
3993                                  G_("ISO C forbids initialization between "
3994                                     "function pointer and %<void *%>"),
3995                                  G_("ISO C forbids return between function "
3996                                     "pointer and %<void *%>"));
3997           /* Const and volatile mean something different for function types,
3998              so the usual warnings are not appropriate.  */
3999           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4000                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4001             {
4002               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4003                 {
4004                   /* Types differing only by the presence of the 'volatile'
4005                      qualifier are acceptable if the 'volatile' has been added
4006                      in by the Objective-C EH machinery.  */
4007                   if (!objc_type_quals_match (ttl, ttr))
4008                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4009                                             "qualifiers from pointer target type"),
4010                                          G_("assignment discards qualifiers "
4011                                             "from pointer target type"),
4012                                          G_("initialization discards qualifiers "
4013                                             "from pointer target type"),
4014                                          G_("return discards qualifiers from "
4015                                             "pointer target type"));
4016                 }
4017               /* If this is not a case of ignoring a mismatch in signedness,
4018                  no warning.  */
4019               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4020                        || target_cmp)
4021                 ;
4022               /* If there is a mismatch, do warn.  */
4023               else if (warn_pointer_sign)
4024                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4025                                         "%d of %qE differ in signedness"),
4026                                      G_("pointer targets in assignment "
4027                                         "differ in signedness"),
4028                                      G_("pointer targets in initialization "
4029                                         "differ in signedness"),
4030                                      G_("pointer targets in return differ "
4031                                         "in signedness"));
4032             }
4033           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4034                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4035             {
4036               /* Because const and volatile on functions are restrictions
4037                  that say the function will not do certain things,
4038                  it is okay to use a const or volatile function
4039                  where an ordinary one is wanted, but not vice-versa.  */
4040               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4041                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4042                                         "qualified function pointer "
4043                                         "from unqualified"),
4044                                      G_("assignment makes qualified function "
4045                                         "pointer from unqualified"),
4046                                      G_("initialization makes qualified "
4047                                         "function pointer from unqualified"),
4048                                      G_("return makes qualified function "
4049                                         "pointer from unqualified"));
4050             }
4051         }
4052       else
4053         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4054         if (!objc_ok)
4055           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4056                                   "incompatible pointer type"),
4057                                G_("assignment from incompatible pointer type"),
4058                                G_("initialization from incompatible "
4059                                   "pointer type"),
4060                                G_("return from incompatible pointer type"));
4061
4062       return convert (type, rhs);
4063     }
4064   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4065     {
4066       /* ??? This should not be an error when inlining calls to
4067          unprototyped functions.  */
4068       error ("invalid use of non-lvalue array");
4069       return error_mark_node;
4070     }
4071   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4072     {
4073       /* An explicit constant 0 can convert to a pointer,
4074          or one that results from arithmetic, even including
4075          a cast to integer type.  */
4076       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
4077           &&
4078           !(TREE_CODE (rhs) == NOP_EXPR
4079             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
4080             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
4081             && integer_zerop (TREE_OPERAND (rhs, 0))))
4082         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4083                                 "pointer from integer without a cast"),
4084                              G_("assignment makes pointer from integer "
4085                                 "without a cast"),
4086                              G_("initialization makes pointer from "
4087                                 "integer without a cast"),
4088                              G_("return makes pointer from integer "
4089                                 "without a cast"));
4090
4091       return convert (type, rhs);
4092     }
4093   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4094     {
4095       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4096                               "from pointer without a cast"),
4097                            G_("assignment makes integer from pointer "
4098                               "without a cast"),
4099                            G_("initialization makes integer from pointer "
4100                               "without a cast"),
4101                            G_("return makes integer from pointer "
4102                               "without a cast"));
4103       return convert (type, rhs);
4104     }
4105   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4106     return convert (type, rhs);
4107
4108   switch (errtype)
4109     {
4110     case ic_argpass:
4111     case ic_argpass_nonproto:
4112       /* ??? This should not be an error when inlining calls to
4113          unprototyped functions.  */
4114       error ("incompatible type for argument %d of %qE", parmnum, rname);
4115       break;
4116     case ic_assign:
4117       error ("incompatible types in assignment");
4118       break;
4119     case ic_init:
4120       error ("incompatible types in initialization");
4121       break;
4122     case ic_return:
4123       error ("incompatible types in return");
4124       break;
4125     default:
4126       gcc_unreachable ();
4127     }
4128
4129   return error_mark_node;
4130 }
4131
4132 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4133    is used for error and waring reporting and indicates which argument
4134    is being processed.  */
4135
4136 tree
4137 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4138 {
4139   tree ret, type;
4140
4141   /* If FN was prototyped, the value has been converted already
4142      in convert_arguments.  */
4143   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4144     return value;
4145
4146   type = TREE_TYPE (parm);
4147   ret = convert_for_assignment (type, value,
4148                                 ic_argpass_nonproto, fn,
4149                                 fn, argnum);
4150   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4151       && INTEGRAL_TYPE_P (type)
4152       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4153     ret = default_conversion (ret);
4154   return ret;
4155 }
4156 \f
4157 /* If VALUE is a compound expr all of whose expressions are constant, then
4158    return its value.  Otherwise, return error_mark_node.
4159
4160    This is for handling COMPOUND_EXPRs as initializer elements
4161    which is allowed with a warning when -pedantic is specified.  */
4162
4163 static tree
4164 valid_compound_expr_initializer (tree value, tree endtype)
4165 {
4166   if (TREE_CODE (value) == COMPOUND_EXPR)
4167     {
4168       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4169           == error_mark_node)
4170         return error_mark_node;
4171       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4172                                               endtype);
4173     }
4174   else if (!initializer_constant_valid_p (value, endtype))
4175     return error_mark_node;
4176   else
4177     return value;
4178 }
4179 \f
4180 /* Perform appropriate conversions on the initial value of a variable,
4181    store it in the declaration DECL,
4182    and print any error messages that are appropriate.
4183    If the init is invalid, store an ERROR_MARK.  */
4184
4185 void
4186 store_init_value (tree decl, tree init)
4187 {
4188   tree value, type;
4189
4190   /* If variable's type was invalidly declared, just ignore it.  */
4191
4192   type = TREE_TYPE (decl);
4193   if (TREE_CODE (type) == ERROR_MARK)
4194     return;
4195
4196   /* Digest the specified initializer into an expression.  */
4197
4198   value = digest_init (type, init, true, TREE_STATIC (decl));
4199
4200   /* Store the expression if valid; else report error.  */
4201
4202   if (!in_system_header
4203       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4204     warning (OPT_Wtraditional, "traditional C rejects automatic "
4205              "aggregate initialization");
4206
4207   DECL_INITIAL (decl) = value;
4208
4209   /* ANSI wants warnings about out-of-range constant initializers.  */
4210   STRIP_TYPE_NOPS (value);
4211   constant_expression_warning (value);
4212
4213   /* Check if we need to set array size from compound literal size.  */
4214   if (TREE_CODE (type) == ARRAY_TYPE
4215       && TYPE_DOMAIN (type) == 0
4216       && value != error_mark_node)
4217     {
4218       tree inside_init = init;
4219
4220       STRIP_TYPE_NOPS (inside_init);
4221       inside_init = fold (inside_init);
4222
4223       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4224         {
4225           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4226
4227           if (TYPE_DOMAIN (TREE_TYPE (decl)))
4228             {
4229               /* For int foo[] = (int [3]){1}; we need to set array size
4230                  now since later on array initializer will be just the
4231                  brace enclosed list of the compound literal.  */
4232               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (decl));
4233               layout_type (type);
4234               layout_decl (decl, 0);
4235             }
4236         }
4237     }
4238 }
4239 \f
4240 /* Methods for storing and printing names for error messages.  */
4241
4242 /* Implement a spelling stack that allows components of a name to be pushed
4243    and popped.  Each element on the stack is this structure.  */
4244
4245 struct spelling
4246 {
4247   int kind;
4248   union
4249     {
4250       int i;
4251       const char *s;
4252     } u;
4253 };
4254
4255 #define SPELLING_STRING 1
4256 #define SPELLING_MEMBER 2
4257 #define SPELLING_BOUNDS 3
4258
4259 static struct spelling *spelling;       /* Next stack element (unused).  */
4260 static struct spelling *spelling_base;  /* Spelling stack base.  */
4261 static int spelling_size;               /* Size of the spelling stack.  */
4262
4263 /* Macros to save and restore the spelling stack around push_... functions.
4264    Alternative to SAVE_SPELLING_STACK.  */
4265
4266 #define SPELLING_DEPTH() (spelling - spelling_base)
4267 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4268
4269 /* Push an element on the spelling stack with type KIND and assign VALUE
4270    to MEMBER.  */
4271
4272 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4273 {                                                                       \
4274   int depth = SPELLING_DEPTH ();                                        \
4275                                                                         \
4276   if (depth >= spelling_size)                                           \
4277     {                                                                   \
4278       spelling_size += 10;                                              \
4279       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4280                                   spelling_size);                       \
4281       RESTORE_SPELLING_DEPTH (depth);                                   \
4282     }                                                                   \
4283                                                                         \
4284   spelling->kind = (KIND);                                              \
4285   spelling->MEMBER = (VALUE);                                           \
4286   spelling++;                                                           \
4287 }
4288
4289 /* Push STRING on the stack.  Printed literally.  */
4290
4291 static void
4292 push_string (const char *string)
4293 {
4294   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4295 }
4296
4297 /* Push a member name on the stack.  Printed as '.' STRING.  */
4298
4299 static void
4300 push_member_name (tree decl)
4301 {
4302   const char *const string
4303     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4304   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4305 }
4306
4307 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4308
4309 static void
4310 push_array_bounds (int bounds)
4311 {
4312   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4313 }
4314
4315 /* Compute the maximum size in bytes of the printed spelling.  */
4316
4317 static int
4318 spelling_length (void)
4319 {
4320   int size = 0;
4321   struct spelling *p;
4322
4323   for (p = spelling_base; p < spelling; p++)
4324     {
4325       if (p->kind == SPELLING_BOUNDS)
4326         size += 25;
4327       else
4328         size += strlen (p->u.s) + 1;
4329     }
4330
4331   return size;
4332 }
4333
4334 /* Print the spelling to BUFFER and return it.  */
4335
4336 static char *
4337 print_spelling (char *buffer)
4338 {
4339   char *d = buffer;
4340   struct spelling *p;
4341
4342   for (p = spelling_base; p < spelling; p++)
4343     if (p->kind == SPELLING_BOUNDS)
4344       {
4345         sprintf (d, "[%d]", p->u.i);
4346         d += strlen (d);
4347       }
4348     else
4349       {
4350         const char *s;
4351         if (p->kind == SPELLING_MEMBER)
4352           *d++ = '.';
4353         for (s = p->u.s; (*d = *s++); d++)
4354           ;
4355       }
4356   *d++ = '\0';
4357   return buffer;
4358 }
4359
4360 /* Issue an error message for a bad initializer component.
4361    MSGID identifies the message.
4362    The component name is taken from the spelling stack.  */
4363
4364 void
4365 error_init (const char *msgid)
4366 {
4367   char *ofwhat;
4368
4369   error ("%s", _(msgid));
4370   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4371   if (*ofwhat)
4372     error ("(near initialization for %qs)", ofwhat);
4373 }
4374
4375 /* Issue a pedantic warning for a bad initializer component.
4376    MSGID identifies the message.
4377    The component name is taken from the spelling stack.  */
4378
4379 void
4380 pedwarn_init (const char *msgid)
4381 {
4382   char *ofwhat;
4383
4384   pedwarn ("%s", _(msgid));
4385   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4386   if (*ofwhat)
4387     pedwarn ("(near initialization for %qs)", ofwhat);
4388 }
4389
4390 /* Issue a warning for a bad initializer component.
4391    MSGID identifies the message.
4392    The component name is taken from the spelling stack.  */
4393
4394 static void
4395 warning_init (const char *msgid)
4396 {
4397   char *ofwhat;
4398
4399   warning (0, "%s", _(msgid));
4400   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4401   if (*ofwhat)
4402     warning (0, "(near initialization for %qs)", ofwhat);
4403 }
4404 \f
4405 /* If TYPE is an array type and EXPR is a parenthesized string
4406    constant, warn if pedantic that EXPR is being used to initialize an
4407    object of type TYPE.  */
4408
4409 void
4410 maybe_warn_string_init (tree type, struct c_expr expr)
4411 {
4412   if (pedantic
4413       && TREE_CODE (type) == ARRAY_TYPE
4414       && TREE_CODE (expr.value) == STRING_CST
4415       && expr.original_code != STRING_CST)
4416     pedwarn_init ("array initialized from parenthesized string constant");
4417 }
4418
4419 /* Digest the parser output INIT as an initializer for type TYPE.
4420    Return a C expression of type TYPE to represent the initial value.
4421
4422    If INIT is a string constant, STRICT_STRING is true if it is
4423    unparenthesized or we should not warn here for it being parenthesized.
4424    For other types of INIT, STRICT_STRING is not used.
4425
4426    REQUIRE_CONSTANT requests an error if non-constant initializers or
4427    elements are seen.  */
4428
4429 static tree
4430 digest_init (tree type, tree init, bool strict_string, int require_constant)
4431 {
4432   enum tree_code code = TREE_CODE (type);
4433   tree inside_init = init;
4434
4435   if (type == error_mark_node
4436       || init == error_mark_node
4437       || TREE_TYPE (init) == error_mark_node)
4438     return error_mark_node;
4439
4440   STRIP_TYPE_NOPS (inside_init);
4441
4442   inside_init = fold (inside_init);
4443
4444   /* Initialization of an array of chars from a string constant
4445      optionally enclosed in braces.  */
4446
4447   if (code == ARRAY_TYPE && inside_init
4448       && TREE_CODE (inside_init) == STRING_CST)
4449     {
4450       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4451       /* Note that an array could be both an array of character type
4452          and an array of wchar_t if wchar_t is signed char or unsigned
4453          char.  */
4454       bool char_array = (typ1 == char_type_node
4455                          || typ1 == signed_char_type_node
4456                          || typ1 == unsigned_char_type_node);
4457       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4458       if (char_array || wchar_array)
4459         {
4460           struct c_expr expr;
4461           bool char_string;
4462           expr.value = inside_init;
4463           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4464           maybe_warn_string_init (type, expr);
4465
4466           char_string
4467             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4468                == char_type_node);
4469
4470           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4471                          TYPE_MAIN_VARIANT (type)))
4472             return inside_init;
4473
4474           if (!wchar_array && !char_string)
4475             {
4476               error_init ("char-array initialized from wide string");
4477               return error_mark_node;
4478             }
4479           if (char_string && !char_array)
4480             {
4481               error_init ("wchar_t-array initialized from non-wide string");
4482               return error_mark_node;
4483             }
4484
4485           TREE_TYPE (inside_init) = type;
4486           if (TYPE_DOMAIN (type) != 0
4487               && TYPE_SIZE (type) != 0
4488               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4489               /* Subtract 1 (or sizeof (wchar_t))
4490                  because it's ok to ignore the terminating null char
4491                  that is counted in the length of the constant.  */
4492               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4493                                        TREE_STRING_LENGTH (inside_init)
4494                                        - ((TYPE_PRECISION (typ1)
4495                                            != TYPE_PRECISION (char_type_node))
4496                                           ? (TYPE_PRECISION (wchar_type_node)
4497                                              / BITS_PER_UNIT)
4498                                           : 1)))
4499             pedwarn_init ("initializer-string for array of chars is too long");
4500
4501           return inside_init;
4502         }
4503       else if (INTEGRAL_TYPE_P (typ1))
4504         {
4505           error_init ("array of inappropriate type initialized "
4506                       "from string constant");
4507           return error_mark_node;
4508         }
4509     }
4510
4511   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4512      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4513      below and handle as a constructor.  */
4514   if (code == VECTOR_TYPE
4515       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4516       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4517       && TREE_CONSTANT (inside_init))
4518     {
4519       if (TREE_CODE (inside_init) == VECTOR_CST
4520           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4521                         TYPE_MAIN_VARIANT (type)))
4522         return inside_init;
4523
4524       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4525         {
4526           unsigned HOST_WIDE_INT ix;
4527           tree value;
4528           bool constant_p = true;
4529
4530           /* Iterate through elements and check if all constructor
4531              elements are *_CSTs.  */
4532           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4533             if (!CONSTANT_CLASS_P (value))
4534               {
4535                 constant_p = false;
4536                 break;
4537               }
4538
4539           if (constant_p)
4540             return build_vector_from_ctor (type,
4541                                            CONSTRUCTOR_ELTS (inside_init));
4542         }
4543     }
4544
4545   /* Any type can be initialized
4546      from an expression of the same type, optionally with braces.  */
4547
4548   if (inside_init && TREE_TYPE (inside_init) != 0
4549       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4550                      TYPE_MAIN_VARIANT (type))
4551           || (code == ARRAY_TYPE
4552               && comptypes (TREE_TYPE (inside_init), type))
4553           || (code == VECTOR_TYPE
4554               && comptypes (TREE_TYPE (inside_init), type))
4555           || (code == POINTER_TYPE
4556               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4557               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4558                             TREE_TYPE (type)))))
4559     {
4560       if (code == POINTER_TYPE)
4561         {
4562           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4563             {
4564               if (TREE_CODE (inside_init) == STRING_CST
4565                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4566                 inside_init = array_to_pointer_conversion (inside_init);
4567               else
4568                 {
4569                   error_init ("invalid use of non-lvalue array");
4570                   return error_mark_node;
4571                 }
4572             }
4573         }
4574
4575       if (code == VECTOR_TYPE)
4576         /* Although the types are compatible, we may require a
4577            conversion.  */
4578         inside_init = convert (type, inside_init);
4579
4580       if (require_constant && !flag_isoc99
4581           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4582         {
4583           /* As an extension, allow initializing objects with static storage
4584              duration with compound literals (which are then treated just as
4585              the brace enclosed list they contain).  */
4586           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4587           inside_init = DECL_INITIAL (decl);
4588         }
4589
4590       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4591           && TREE_CODE (inside_init) != CONSTRUCTOR)
4592         {
4593           error_init ("array initialized from non-constant array expression");
4594           return error_mark_node;
4595         }
4596
4597       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4598         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4599
4600       /* Compound expressions can only occur here if -pedantic or
4601          -pedantic-errors is specified.  In the later case, we always want
4602          an error.  In the former case, we simply want a warning.  */
4603       if (require_constant && pedantic
4604           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4605         {
4606           inside_init
4607             = valid_compound_expr_initializer (inside_init,
4608                                                TREE_TYPE (inside_init));
4609           if (inside_init == error_mark_node)
4610             error_init ("initializer element is not constant");
4611           else
4612             pedwarn_init ("initializer element is not constant");
4613           if (flag_pedantic_errors)
4614             inside_init = error_mark_node;
4615         }
4616       else if (require_constant
4617                && !initializer_constant_valid_p (inside_init,
4618                                                  TREE_TYPE (inside_init)))
4619         {
4620           error_init ("initializer element is not constant");
4621           inside_init = error_mark_node;
4622         }
4623
4624       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4625       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4626         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4627                                               NULL_TREE, 0);
4628       return inside_init;
4629     }
4630
4631   /* Handle scalar types, including conversions.  */
4632
4633   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4634       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4635       || code == VECTOR_TYPE)
4636     {
4637       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4638           && (TREE_CODE (init) == STRING_CST
4639               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4640         init = array_to_pointer_conversion (init);
4641       inside_init
4642         = convert_for_assignment (type, init, ic_init,
4643                                   NULL_TREE, NULL_TREE, 0);
4644
4645       /* Check to see if we have already given an error message.  */
4646       if (inside_init == error_mark_node)
4647         ;
4648       else if (require_constant && !TREE_CONSTANT (inside_init))
4649         {
4650           error_init ("initializer element is not constant");
4651           inside_init = error_mark_node;
4652         }
4653       else if (require_constant
4654                && !initializer_constant_valid_p (inside_init,
4655                                                  TREE_TYPE (inside_init)))
4656         {
4657           error_init ("initializer element is not computable at load time");
4658           inside_init = error_mark_node;
4659         }
4660
4661       return inside_init;
4662     }
4663
4664   /* Come here only for records and arrays.  */
4665
4666   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4667     {
4668       error_init ("variable-sized object may not be initialized");
4669       return error_mark_node;
4670     }
4671
4672   error_init ("invalid initializer");
4673   return error_mark_node;
4674 }
4675 \f
4676 /* Handle initializers that use braces.  */
4677
4678 /* Type of object we are accumulating a constructor for.
4679    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4680 static tree constructor_type;
4681
4682 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4683    left to fill.  */
4684 static tree constructor_fields;
4685
4686 /* For an ARRAY_TYPE, this is the specified index
4687    at which to store the next element we get.  */
4688 static tree constructor_index;
4689
4690 /* For an ARRAY_TYPE, this is the maximum index.  */
4691 static tree constructor_max_index;
4692
4693 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4694 static tree constructor_unfilled_fields;
4695
4696 /* For an ARRAY_TYPE, this is the index of the first element
4697    not yet written out.  */
4698 static tree constructor_unfilled_index;
4699
4700 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4701    This is so we can generate gaps between fields, when appropriate.  */
4702 static tree constructor_bit_index;
4703
4704 /* If we are saving up the elements rather than allocating them,
4705    this is the list of elements so far (in reverse order,
4706    most recent first).  */
4707 static VEC(constructor_elt,gc) *constructor_elements;
4708
4709 /* 1 if constructor should be incrementally stored into a constructor chain,
4710    0 if all the elements should be kept in AVL tree.  */
4711 static int constructor_incremental;
4712
4713 /* 1 if so far this constructor's elements are all compile-time constants.  */
4714 static int constructor_constant;
4715
4716 /* 1 if so far this constructor's elements are all valid address constants.  */
4717 static int constructor_simple;
4718
4719 /* 1 if this constructor is erroneous so far.  */
4720 static int constructor_erroneous;
4721
4722 /* Structure for managing pending initializer elements, organized as an
4723    AVL tree.  */
4724
4725 struct init_node
4726 {
4727   struct init_node *left, *right;
4728   struct init_node *parent;
4729   int balance;
4730   tree purpose;
4731   tree value;
4732 };
4733
4734 /* Tree of pending elements at this constructor level.
4735    These are elements encountered out of order
4736    which belong at places we haven't reached yet in actually
4737    writing the output.
4738    Will never hold tree nodes across GC runs.  */
4739 static struct init_node *constructor_pending_elts;
4740
4741 /* The SPELLING_DEPTH of this constructor.  */
4742 static int constructor_depth;
4743
4744 /* DECL node for which an initializer is being read.
4745    0 means we are reading a constructor expression
4746    such as (struct foo) {...}.  */
4747 static tree constructor_decl;
4748
4749 /* Nonzero if this is an initializer for a top-level decl.  */
4750 static int constructor_top_level;
4751
4752 /* Nonzero if there were any member designators in this initializer.  */
4753 static int constructor_designated;
4754
4755 /* Nesting depth of designator list.  */
4756 static int designator_depth;
4757
4758 /* Nonzero if there were diagnosed errors in this designator list.  */
4759 static int designator_erroneous;
4760
4761 \f
4762 /* This stack has a level for each implicit or explicit level of
4763    structuring in the initializer, including the outermost one.  It
4764    saves the values of most of the variables above.  */
4765
4766 struct constructor_range_stack;
4767
4768 struct constructor_stack
4769 {
4770   struct constructor_stack *next;
4771   tree type;
4772   tree fields;
4773   tree index;
4774   tree max_index;
4775   tree unfilled_index;
4776   tree unfilled_fields;
4777   tree bit_index;
4778   VEC(constructor_elt,gc) *elements;
4779   struct init_node *pending_elts;
4780   int offset;
4781   int depth;
4782   /* If value nonzero, this value should replace the entire
4783      constructor at this level.  */
4784   struct c_expr replacement_value;
4785   struct constructor_range_stack *range_stack;
4786   char constant;
4787   char simple;
4788   char implicit;
4789   char erroneous;
4790   char outer;
4791   char incremental;
4792   char designated;
4793 };
4794
4795 static struct constructor_stack *constructor_stack;
4796
4797 /* This stack represents designators from some range designator up to
4798    the last designator in the list.  */
4799
4800 struct constructor_range_stack
4801 {
4802   struct constructor_range_stack *next, *prev;
4803   struct constructor_stack *stack;
4804   tree range_start;
4805   tree index;
4806   tree range_end;
4807   tree fields;
4808 };
4809
4810 static struct constructor_range_stack *constructor_range_stack;
4811
4812 /* This stack records separate initializers that are nested.
4813    Nested initializers can't happen in ANSI C, but GNU C allows them
4814    in cases like { ... (struct foo) { ... } ... }.  */
4815
4816 struct initializer_stack
4817 {
4818   struct initializer_stack *next;
4819   tree decl;
4820   struct constructor_stack *constructor_stack;
4821   struct constructor_range_stack *constructor_range_stack;
4822   VEC(constructor_elt,gc) *elements;
4823   struct spelling *spelling;
4824   struct spelling *spelling_base;
4825   int spelling_size;
4826   char top_level;
4827   char require_constant_value;
4828   char require_constant_elements;
4829 };
4830
4831 static struct initializer_stack *initializer_stack;
4832 \f
4833 /* Prepare to parse and output the initializer for variable DECL.  */
4834
4835 void
4836 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4837 {
4838   const char *locus;
4839   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4840
4841   p->decl = constructor_decl;
4842   p->require_constant_value = require_constant_value;
4843   p->require_constant_elements = require_constant_elements;
4844   p->constructor_stack = constructor_stack;
4845   p->constructor_range_stack = constructor_range_stack;
4846   p->elements = constructor_elements;
4847   p->spelling = spelling;
4848   p->spelling_base = spelling_base;
4849   p->spelling_size = spelling_size;
4850   p->top_level = constructor_top_level;
4851   p->next = initializer_stack;
4852   initializer_stack = p;
4853
4854   constructor_decl = decl;
4855   constructor_designated = 0;
4856   constructor_top_level = top_level;
4857
4858   if (decl != 0 && decl != error_mark_node)
4859     {
4860       require_constant_value = TREE_STATIC (decl);
4861       require_constant_elements
4862         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4863            /* For a scalar, you can always use any value to initialize,
4864               even within braces.  */
4865            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4866                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4867                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4868                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4869       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4870     }
4871   else
4872     {
4873       require_constant_value = 0;
4874       require_constant_elements = 0;
4875       locus = "(anonymous)";
4876     }
4877
4878   constructor_stack = 0;
4879   constructor_range_stack = 0;
4880
4881   missing_braces_mentioned = 0;
4882
4883   spelling_base = 0;
4884   spelling_size = 0;
4885   RESTORE_SPELLING_DEPTH (0);
4886
4887   if (locus)
4888     push_string (locus);
4889 }
4890
4891 void
4892 finish_init (void)
4893 {
4894   struct initializer_stack *p = initializer_stack;
4895
4896   /* Free the whole constructor stack of this initializer.  */
4897   while (constructor_stack)
4898     {
4899       struct constructor_stack *q = constructor_stack;
4900       constructor_stack = q->next;
4901       free (q);
4902     }
4903
4904   gcc_assert (!constructor_range_stack);
4905
4906   /* Pop back to the data of the outer initializer (if any).  */
4907   free (spelling_base);
4908
4909   constructor_decl = p->decl;
4910   require_constant_value = p->require_constant_value;
4911   require_constant_elements = p->require_constant_elements;
4912   constructor_stack = p->constructor_stack;
4913   constructor_range_stack = p->constructor_range_stack;
4914   constructor_elements = p->elements;
4915   spelling = p->spelling;
4916   spelling_base = p->spelling_base;
4917   spelling_size = p->spelling_size;
4918   constructor_top_level = p->top_level;
4919   initializer_stack = p->next;
4920   free (p);
4921 }
4922 \f
4923 /* Call here when we see the initializer is surrounded by braces.
4924    This is instead of a call to push_init_level;
4925    it is matched by a call to pop_init_level.
4926
4927    TYPE is the type to initialize, for a constructor expression.
4928    For an initializer for a decl, TYPE is zero.  */
4929
4930 void
4931 really_start_incremental_init (tree type)
4932 {
4933   struct constructor_stack *p = XNEW (struct constructor_stack);
4934
4935   if (type == 0)
4936     type = TREE_TYPE (constructor_decl);
4937
4938   if (targetm.vector_opaque_p (type))
4939     error ("opaque vector types cannot be initialized");
4940
4941   p->type = constructor_type;
4942   p->fields = constructor_fields;
4943   p->index = constructor_index;
4944   p->max_index = constructor_max_index;
4945   p->unfilled_index = constructor_unfilled_index;
4946   p->unfilled_fields = constructor_unfilled_fields;
4947   p->bit_index = constructor_bit_index;
4948   p->elements = constructor_elements;
4949   p->constant = constructor_constant;
4950   p->simple = constructor_simple;
4951   p->erroneous = constructor_erroneous;
4952   p->pending_elts = constructor_pending_elts;
4953   p->depth = constructor_depth;
4954   p->replacement_value.value = 0;
4955   p->replacement_value.original_code = ERROR_MARK;
4956   p->implicit = 0;
4957   p->range_stack = 0;
4958   p->outer = 0;
4959   p->incremental = constructor_incremental;
4960   p->designated = constructor_designated;
4961   p->next = 0;
4962   constructor_stack = p;
4963
4964   constructor_constant = 1;
4965   constructor_simple = 1;
4966   constructor_depth = SPELLING_DEPTH ();
4967   constructor_elements = 0;
4968   constructor_pending_elts = 0;
4969   constructor_type = type;
4970   constructor_incremental = 1;
4971   constructor_designated = 0;
4972   designator_depth = 0;
4973   designator_erroneous = 0;
4974
4975   if (TREE_CODE (constructor_type) == RECORD_TYPE
4976       || TREE_CODE (constructor_type) == UNION_TYPE)
4977     {
4978       constructor_fields = TYPE_FIELDS (constructor_type);
4979       /* Skip any nameless bit fields at the beginning.  */
4980       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4981              && DECL_NAME (constructor_fields) == 0)
4982         constructor_fields = TREE_CHAIN (constructor_fields);
4983
4984       constructor_unfilled_fields = constructor_fields;
4985       constructor_bit_index = bitsize_zero_node;
4986     }
4987   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4988     {
4989       if (TYPE_DOMAIN (constructor_type))
4990         {
4991           constructor_max_index
4992             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4993
4994           /* Detect non-empty initializations of zero-length arrays.  */
4995           if (constructor_max_index == NULL_TREE
4996               && TYPE_SIZE (constructor_type))
4997             constructor_max_index = build_int_cst (NULL_TREE, -1);
4998
4999           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5000              to initialize VLAs will cause a proper error; avoid tree
5001              checking errors as well by setting a safe value.  */
5002           if (constructor_max_index
5003               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5004             constructor_max_index = build_int_cst (NULL_TREE, -1);
5005
5006           constructor_index
5007             = convert (bitsizetype,
5008                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5009         }
5010       else
5011         {
5012           constructor_index = bitsize_zero_node;
5013           constructor_max_index = NULL_TREE;
5014         }
5015
5016       constructor_unfilled_index = constructor_index;
5017     }
5018   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5019     {
5020       /* Vectors are like simple fixed-size arrays.  */
5021       constructor_max_index =
5022         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5023       constructor_index = convert (bitsizetype, bitsize_zero_node);
5024       constructor_unfilled_index = constructor_index;
5025     }
5026   else
5027     {
5028       /* Handle the case of int x = {5}; */
5029       constructor_fields = constructor_type;
5030       constructor_unfilled_fields = constructor_type;
5031     }
5032 }
5033 \f
5034 /* Push down into a subobject, for initialization.
5035    If this is for an explicit set of braces, IMPLICIT is 0.
5036    If it is because the next element belongs at a lower level,
5037    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5038
5039 void
5040 push_init_level (int implicit)
5041 {
5042   struct constructor_stack *p;
5043   tree value = NULL_TREE;
5044
5045   /* If we've exhausted any levels that didn't have braces,
5046      pop them now.  If implicit == 1, this will have been done in
5047      process_init_element; do not repeat it here because in the case
5048      of excess initializers for an empty aggregate this leads to an
5049      infinite cycle of popping a level and immediately recreating
5050      it.  */
5051   if (implicit != 1)
5052     {
5053       while (constructor_stack->implicit)
5054         {
5055           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5056                || TREE_CODE (constructor_type) == UNION_TYPE)
5057               && constructor_fields == 0)
5058             process_init_element (pop_init_level (1));
5059           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5060                    && constructor_max_index
5061                    && tree_int_cst_lt (constructor_max_index,
5062                                        constructor_index))
5063             process_init_element (pop_init_level (1));
5064           else
5065             break;
5066         }
5067     }
5068
5069   /* Unless this is an explicit brace, we need to preserve previous
5070      content if any.  */
5071   if (implicit)
5072     {
5073       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5074            || TREE_CODE (constructor_type) == UNION_TYPE)
5075           && constructor_fields)
5076         value = find_init_member (constructor_fields);
5077       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5078         value = find_init_member (constructor_index);
5079     }
5080
5081   p = XNEW (struct constructor_stack);
5082   p->type = constructor_type;
5083   p->fields = constructor_fields;
5084   p->index = constructor_index;
5085   p->max_index = constructor_max_index;
5086   p->unfilled_index = constructor_unfilled_index;
5087   p->unfilled_fields = constructor_unfilled_fields;
5088   p->bit_index = constructor_bit_index;
5089   p->elements = constructor_elements;
5090   p->constant = constructor_constant;
5091   p->simple = constructor_simple;
5092   p->erroneous = constructor_erroneous;
5093   p->pending_elts = constructor_pending_elts;
5094   p->depth = constructor_depth;
5095   p->replacement_value.value = 0;
5096   p->replacement_value.original_code = ERROR_MARK;
5097   p->implicit = implicit;
5098   p->outer = 0;
5099   p->incremental = constructor_incremental;
5100   p->designated = constructor_designated;
5101   p->next = constructor_stack;
5102   p->range_stack = 0;
5103   constructor_stack = p;
5104
5105   constructor_constant = 1;
5106   constructor_simple = 1;
5107   constructor_depth = SPELLING_DEPTH ();
5108   constructor_elements = 0;
5109   constructor_incremental = 1;
5110   constructor_designated = 0;
5111   constructor_pending_elts = 0;
5112   if (!implicit)
5113     {
5114       p->range_stack = constructor_range_stack;
5115       constructor_range_stack = 0;
5116       designator_depth = 0;
5117       designator_erroneous = 0;
5118     }
5119
5120   /* Don't die if an entire brace-pair level is superfluous
5121      in the containing level.  */
5122   if (constructor_type == 0)
5123     ;
5124   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5125            || TREE_CODE (constructor_type) == UNION_TYPE)
5126     {
5127       /* Don't die if there are extra init elts at the end.  */
5128       if (constructor_fields == 0)
5129         constructor_type = 0;
5130       else
5131         {
5132           constructor_type = TREE_TYPE (constructor_fields);
5133           push_member_name (constructor_fields);
5134           constructor_depth++;
5135         }
5136     }
5137   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5138     {
5139       constructor_type = TREE_TYPE (constructor_type);
5140       push_array_bounds (tree_low_cst (constructor_index, 0));
5141       constructor_depth++;
5142     }
5143
5144   if (constructor_type == 0)
5145     {
5146       error_init ("extra brace group at end of initializer");
5147       constructor_fields = 0;
5148       constructor_unfilled_fields = 0;
5149       return;
5150     }
5151
5152   if (value && TREE_CODE (value) == CONSTRUCTOR)
5153     {
5154       constructor_constant = TREE_CONSTANT (value);
5155       constructor_simple = TREE_STATIC (value);
5156       constructor_elements = CONSTRUCTOR_ELTS (value);
5157       if (!VEC_empty (constructor_elt, constructor_elements)
5158           && (TREE_CODE (constructor_type) == RECORD_TYPE
5159               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5160         set_nonincremental_init ();
5161     }
5162
5163   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5164     {
5165       missing_braces_mentioned = 1;
5166       warning_init ("missing braces around initializer");
5167     }
5168
5169   if (TREE_CODE (constructor_type) == RECORD_TYPE
5170            || TREE_CODE (constructor_type) == UNION_TYPE)
5171     {
5172       constructor_fields = TYPE_FIELDS (constructor_type);
5173       /* Skip any nameless bit fields at the beginning.  */
5174       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5175              && DECL_NAME (constructor_fields) == 0)
5176         constructor_fields = TREE_CHAIN (constructor_fields);
5177
5178       constructor_unfilled_fields = constructor_fields;
5179       constructor_bit_index = bitsize_zero_node;
5180     }
5181   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5182     {
5183       /* Vectors are like simple fixed-size arrays.  */
5184       constructor_max_index =
5185         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5186       constructor_index = convert (bitsizetype, integer_zero_node);
5187       constructor_unfilled_index = constructor_index;
5188     }
5189   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5190     {
5191       if (TYPE_DOMAIN (constructor_type))
5192         {
5193           constructor_max_index
5194             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5195
5196           /* Detect non-empty initializations of zero-length arrays.  */
5197           if (constructor_max_index == NULL_TREE
5198               && TYPE_SIZE (constructor_type))
5199             constructor_max_index = build_int_cst (NULL_TREE, -1);
5200
5201           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5202              to initialize VLAs will cause a proper error; avoid tree
5203              checking errors as well by setting a safe value.  */
5204           if (constructor_max_index
5205               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5206             constructor_max_index = build_int_cst (NULL_TREE, -1);
5207
5208           constructor_index
5209             = convert (bitsizetype,
5210                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5211         }
5212       else
5213         constructor_index = bitsize_zero_node;
5214
5215       constructor_unfilled_index = constructor_index;
5216       if (value && TREE_CODE (value) == STRING_CST)
5217         {
5218           /* We need to split the char/wchar array into individual
5219              characters, so that we don't have to special case it
5220              everywhere.  */
5221           set_nonincremental_init_from_string (value);
5222         }
5223     }
5224   else
5225     {
5226       if (constructor_type != error_mark_node)
5227         warning_init ("braces around scalar initializer");
5228       constructor_fields = constructor_type;
5229       constructor_unfilled_fields = constructor_type;
5230     }
5231 }
5232
5233 /* At the end of an implicit or explicit brace level,
5234    finish up that level of constructor.  If a single expression
5235    with redundant braces initialized that level, return the
5236    c_expr structure for that expression.  Otherwise, the original_code
5237    element is set to ERROR_MARK.
5238    If we were outputting the elements as they are read, return 0 as the value
5239    from inner levels (process_init_element ignores that),
5240    but return error_mark_node as the value from the outermost level
5241    (that's what we want to put in DECL_INITIAL).
5242    Otherwise, return a CONSTRUCTOR expression as the value.  */
5243
5244 struct c_expr
5245 pop_init_level (int implicit)
5246 {
5247   struct constructor_stack *p;
5248   struct c_expr ret;
5249   ret.value = 0;
5250   ret.original_code = ERROR_MARK;
5251
5252   if (implicit == 0)
5253     {
5254       /* When we come to an explicit close brace,
5255          pop any inner levels that didn't have explicit braces.  */
5256       while (constructor_stack->implicit)
5257         process_init_element (pop_init_level (1));
5258
5259       gcc_assert (!constructor_range_stack);
5260     }
5261
5262   /* Now output all pending elements.  */
5263   constructor_incremental = 1;
5264   output_pending_init_elements (1);
5265
5266   p = constructor_stack;
5267
5268   /* Error for initializing a flexible array member, or a zero-length
5269      array member in an inappropriate context.  */
5270   if (constructor_type && constructor_fields
5271       && TREE_CODE (constructor_type) == ARRAY_TYPE
5272       && TYPE_DOMAIN (constructor_type)
5273       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5274     {
5275       /* Silently discard empty initializations.  The parser will
5276          already have pedwarned for empty brackets.  */
5277       if (integer_zerop (constructor_unfilled_index))
5278         constructor_type = NULL_TREE;
5279       else
5280         {
5281           gcc_assert (!TYPE_SIZE (constructor_type));
5282
5283           if (constructor_depth > 2)
5284             error_init ("initialization of flexible array member in a nested context");
5285           else if (pedantic)
5286             pedwarn_init ("initialization of a flexible array member");
5287
5288           /* We have already issued an error message for the existence
5289              of a flexible array member not at the end of the structure.
5290              Discard the initializer so that we do not die later.  */
5291           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5292             constructor_type = NULL_TREE;
5293         }
5294     }
5295
5296   /* Warn when some struct elements are implicitly initialized to zero.  */
5297   if (warn_missing_field_initializers
5298       && constructor_type
5299       && TREE_CODE (constructor_type) == RECORD_TYPE
5300       && constructor_unfilled_fields)
5301     {
5302         /* Do not warn for flexible array members or zero-length arrays.  */
5303         while (constructor_unfilled_fields
5304                && (!DECL_SIZE (constructor_unfilled_fields)
5305                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5306           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5307
5308         /* Do not warn if this level of the initializer uses member
5309            designators; it is likely to be deliberate.  */
5310         if (constructor_unfilled_fields && !constructor_designated)
5311           {
5312             push_member_name (constructor_unfilled_fields);
5313             warning_init ("missing initializer");
5314             RESTORE_SPELLING_DEPTH (constructor_depth);
5315           }
5316     }
5317
5318   /* Pad out the end of the structure.  */
5319   if (p->replacement_value.value)
5320     /* If this closes a superfluous brace pair,
5321        just pass out the element between them.  */
5322     ret = p->replacement_value;
5323   else if (constructor_type == 0)
5324     ;
5325   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5326            && TREE_CODE (constructor_type) != UNION_TYPE
5327            && TREE_CODE (constructor_type) != ARRAY_TYPE
5328            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5329     {
5330       /* A nonincremental scalar initializer--just return
5331          the element, after verifying there is just one.  */
5332       if (VEC_empty (constructor_elt,constructor_elements))
5333         {
5334           if (!constructor_erroneous)
5335             error_init ("empty scalar initializer");
5336           ret.value = error_mark_node;
5337         }
5338       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5339         {
5340           error_init ("extra elements in scalar initializer");
5341           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5342         }
5343       else
5344         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5345     }
5346   else
5347     {
5348       if (constructor_erroneous)
5349         ret.value = error_mark_node;
5350       else
5351         {
5352           ret.value = build_constructor (constructor_type,
5353                                          constructor_elements);
5354           if (constructor_constant)
5355             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5356           if (constructor_constant && constructor_simple)
5357             TREE_STATIC (ret.value) = 1;
5358         }
5359     }
5360
5361   constructor_type = p->type;
5362   constructor_fields = p->fields;
5363   constructor_index = p->index;
5364   constructor_max_index = p->max_index;
5365   constructor_unfilled_index = p->unfilled_index;
5366   constructor_unfilled_fields = p->unfilled_fields;
5367   constructor_bit_index = p->bit_index;
5368   constructor_elements = p->elements;
5369   constructor_constant = p->constant;
5370   constructor_simple = p->simple;
5371   constructor_erroneous = p->erroneous;
5372   constructor_incremental = p->incremental;
5373   constructor_designated = p->designated;
5374   constructor_pending_elts = p->pending_elts;
5375   constructor_depth = p->depth;
5376   if (!p->implicit)
5377     constructor_range_stack = p->range_stack;
5378   RESTORE_SPELLING_DEPTH (constructor_depth);
5379
5380   constructor_stack = p->next;
5381   free (p);
5382
5383   if (ret.value == 0)
5384     {
5385       if (constructor_stack == 0)
5386         {
5387           ret.value = error_mark_node;
5388           return ret;
5389         }
5390       return ret;
5391     }
5392   return ret;
5393 }
5394
5395 /* Common handling for both array range and field name designators.
5396    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5397
5398 static int
5399 set_designator (int array)
5400 {
5401   tree subtype;
5402   enum tree_code subcode;
5403
5404   /* Don't die if an entire brace-pair level is superfluous
5405      in the containing level.  */
5406   if (constructor_type == 0)
5407     return 1;
5408
5409   /* If there were errors in this designator list already, bail out
5410      silently.  */
5411   if (designator_erroneous)
5412     return 1;
5413
5414   if (!designator_depth)
5415     {
5416       gcc_assert (!constructor_range_stack);
5417
5418       /* Designator list starts at the level of closest explicit
5419          braces.  */
5420       while (constructor_stack->implicit)
5421         process_init_element (pop_init_level (1));
5422       constructor_designated = 1;
5423       return 0;
5424     }
5425
5426   switch (TREE_CODE (constructor_type))
5427     {
5428     case  RECORD_TYPE:
5429     case  UNION_TYPE:
5430       subtype = TREE_TYPE (constructor_fields);
5431       if (subtype != error_mark_node)
5432         subtype = TYPE_MAIN_VARIANT (subtype);
5433       break;
5434     case ARRAY_TYPE:
5435       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5436       break;
5437     default:
5438       gcc_unreachable ();
5439     }
5440
5441   subcode = TREE_CODE (subtype);
5442   if (array && subcode != ARRAY_TYPE)
5443     {
5444       error_init ("array index in non-array initializer");
5445       return 1;
5446     }
5447   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5448     {
5449       error_init ("field name not in record or union initializer");
5450       return 1;
5451     }
5452
5453   constructor_designated = 1;
5454   push_init_level (2);
5455   return 0;
5456 }
5457
5458 /* If there are range designators in designator list, push a new designator
5459    to constructor_range_stack.  RANGE_END is end of such stack range or
5460    NULL_TREE if there is no range designator at this level.  */
5461
5462 static void
5463 push_range_stack (tree range_end)
5464 {
5465   struct constructor_range_stack *p;
5466
5467   p = GGC_NEW (struct constructor_range_stack);
5468   p->prev = constructor_range_stack;
5469   p->next = 0;
5470   p->fields = constructor_fields;
5471   p->range_start = constructor_index;
5472   p->index = constructor_index;
5473   p->stack = constructor_stack;
5474   p->range_end = range_end;
5475   if (constructor_range_stack)
5476     constructor_range_stack->next = p;
5477   constructor_range_stack = p;
5478 }
5479
5480 /* Within an array initializer, specify the next index to be initialized.
5481    FIRST is that index.  If LAST is nonzero, then initialize a range
5482    of indices, running from FIRST through LAST.  */
5483
5484 void
5485 set_init_index (tree first, tree last)
5486 {
5487   if (set_designator (1))
5488     return;
5489
5490   designator_erroneous = 1;
5491
5492   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5493       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5494     {
5495       error_init ("array index in initializer not of integer type");
5496       return;
5497     }
5498
5499   if (TREE_CODE (first) != INTEGER_CST)
5500     error_init ("nonconstant array index in initializer");
5501   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5502     error_init ("nonconstant array index in initializer");
5503   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5504     error_init ("array index in non-array initializer");
5505   else if (tree_int_cst_sgn (first) == -1)
5506     error_init ("array index in initializer exceeds array bounds");
5507   else if (constructor_max_index
5508            && tree_int_cst_lt (constructor_max_index, first))
5509     error_init ("array index in initializer exceeds array bounds");
5510   else
5511     {
5512       constructor_index = convert (bitsizetype, first);
5513
5514       if (last)
5515         {
5516           if (tree_int_cst_equal (first, last))
5517             last = 0;
5518           else if (tree_int_cst_lt (last, first))
5519             {
5520               error_init ("empty index range in initializer");
5521               last = 0;
5522             }
5523           else
5524             {
5525               last = convert (bitsizetype, last);
5526               if (constructor_max_index != 0
5527                   && tree_int_cst_lt (constructor_max_index, last))
5528                 {
5529                   error_init ("array index range in initializer exceeds array bounds");
5530                   last = 0;
5531                 }
5532             }
5533         }
5534
5535       designator_depth++;
5536       designator_erroneous = 0;
5537       if (constructor_range_stack || last)
5538         push_range_stack (last);
5539     }
5540 }
5541
5542 /* Within a struct initializer, specify the next field to be initialized.  */
5543
5544 void
5545 set_init_label (tree fieldname)
5546 {
5547   tree tail;
5548
5549   if (set_designator (0))
5550     return;
5551
5552   designator_erroneous = 1;
5553
5554   if (TREE_CODE (constructor_type) != RECORD_TYPE
5555       && TREE_CODE (constructor_type) != UNION_TYPE)
5556     {
5557       error_init ("field name not in record or union initializer");
5558       return;
5559     }
5560
5561   for (tail = TYPE_FIELDS (constructor_type); tail;
5562        tail = TREE_CHAIN (tail))
5563     {
5564       if (DECL_NAME (tail) == fieldname)
5565         break;
5566     }
5567
5568   if (tail == 0)
5569     error ("unknown field %qE specified in initializer", fieldname);
5570   else
5571     {
5572       constructor_fields = tail;
5573       designator_depth++;
5574       designator_erroneous = 0;
5575       if (constructor_range_stack)
5576         push_range_stack (NULL_TREE);
5577     }
5578 }
5579 \f
5580 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5581    identifies the initializer, either array index or field in a structure.
5582    VALUE is the value of that index or field.  */
5583
5584 static void
5585 add_pending_init (tree purpose, tree value)
5586 {
5587   struct init_node *p, **q, *r;
5588
5589   q = &constructor_pending_elts;
5590   p = 0;
5591
5592   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5593     {
5594       while (*q != 0)
5595         {
5596           p = *q;
5597           if (tree_int_cst_lt (purpose, p->purpose))
5598             q = &p->left;
5599           else if (tree_int_cst_lt (p->purpose, purpose))
5600             q = &p->right;
5601           else
5602             {
5603               if (TREE_SIDE_EFFECTS (p->value))
5604                 warning_init ("initialized field with side-effects overwritten");
5605               p->value = value;
5606               return;
5607             }
5608         }
5609     }
5610   else
5611     {
5612       tree bitpos;
5613
5614       bitpos = bit_position (purpose);
5615       while (*q != NULL)
5616         {
5617           p = *q;
5618           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5619             q = &p->left;
5620           else if (p->purpose != purpose)
5621             q = &p->right;
5622           else
5623             {
5624               if (TREE_SIDE_EFFECTS (p->value))
5625                 warning_init ("initialized field with side-effects overwritten");
5626               p->value = value;
5627               return;
5628             }
5629         }
5630     }
5631
5632   r = GGC_NEW (struct init_node);
5633   r->purpose = purpose;
5634   r->value = value;
5635
5636   *q = r;
5637   r->parent = p;
5638   r->left = 0;
5639   r->right = 0;
5640   r->balance = 0;
5641
5642   while (p)
5643     {
5644       struct init_node *s;
5645
5646       if (r == p->left)
5647         {
5648           if (p->balance == 0)
5649             p->balance = -1;
5650           else if (p->balance < 0)
5651             {
5652               if (r->balance < 0)
5653                 {
5654                   /* L rotation.  */
5655                   p->left = r->right;
5656                   if (p->left)
5657                     p->left->parent = p;
5658                   r->right = p;
5659
5660                   p->balance = 0;
5661                   r->balance = 0;
5662
5663                   s = p->parent;
5664                   p->parent = r;
5665                   r->parent = s;
5666                   if (s)
5667                     {
5668                       if (s->left == p)
5669                         s->left = r;
5670                       else
5671                         s->right = r;
5672                     }
5673                   else
5674                     constructor_pending_elts = r;
5675                 }
5676               else
5677                 {
5678                   /* LR rotation.  */
5679                   struct init_node *t = r->right;
5680
5681                   r->right = t->left;
5682                   if (r->right)
5683                     r->right->parent = r;
5684                   t->left = r;
5685
5686                   p->left = t->right;
5687                   if (p->left)
5688                     p->left->parent = p;
5689                   t->right = p;
5690
5691                   p->balance = t->balance < 0;
5692                   r->balance = -(t->balance > 0);
5693                   t->balance = 0;
5694
5695                   s = p->parent;
5696                   p->parent = t;
5697                   r->parent = t;
5698                   t->parent = s;
5699                   if (s)
5700                     {
5701                       if (s->left == p)
5702                         s->left = t;
5703                       else
5704                         s->right = t;
5705                     }
5706                   else
5707                     constructor_pending_elts = t;
5708                 }
5709               break;
5710             }
5711           else
5712             {
5713               /* p->balance == +1; growth of left side balances the node.  */
5714               p->balance = 0;
5715               break;
5716             }
5717         }
5718       else /* r == p->right */
5719         {
5720           if (p->balance == 0)
5721             /* Growth propagation from right side.  */
5722             p->balance++;
5723           else if (p->balance > 0)
5724             {
5725               if (r->balance > 0)
5726                 {
5727                   /* R rotation.  */
5728                   p->right = r->left;
5729                   if (p->right)
5730                     p->right->parent = p;
5731                   r->left = p;
5732
5733                   p->balance = 0;
5734                   r->balance = 0;
5735
5736                   s = p->parent;
5737                   p->parent = r;
5738                   r->parent = s;
5739                   if (s)
5740                     {
5741                       if (s->left == p)
5742                         s->left = r;
5743                       else
5744                         s->right = r;
5745                     }
5746                   else
5747                     constructor_pending_elts = r;
5748                 }
5749               else /* r->balance == -1 */
5750                 {
5751                   /* RL rotation */
5752                   struct init_node *t = r->left;
5753
5754                   r->left = t->right;
5755                   if (r->left)
5756                     r->left->parent = r;
5757                   t->right = r;
5758
5759                   p->right = t->left;
5760                   if (p->right)
5761                     p->right->parent = p;
5762                   t->left = p;
5763
5764                   r->balance = (t->balance < 0);
5765                   p->balance = -(t->balance > 0);
5766                   t->balance = 0;
5767
5768                   s = p->parent;
5769                   p->parent = t;
5770                   r->parent = t;
5771                   t->parent = s;
5772                   if (s)
5773                     {
5774                       if (s->left == p)
5775                         s->left = t;
5776                       else
5777                         s->right = t;
5778                     }
5779                   else
5780                     constructor_pending_elts = t;
5781                 }
5782               break;
5783             }
5784           else
5785             {
5786               /* p->balance == -1; growth of right side balances the node.  */
5787               p->balance = 0;
5788               break;
5789             }
5790         }
5791
5792       r = p;
5793       p = p->parent;
5794     }
5795 }
5796
5797 /* Build AVL tree from a sorted chain.  */
5798
5799 static void
5800 set_nonincremental_init (void)
5801 {
5802   unsigned HOST_WIDE_INT ix;
5803   tree index, value;
5804
5805   if (TREE_CODE (constructor_type) != RECORD_TYPE
5806       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5807     return;
5808
5809   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5810     add_pending_init (index, value);
5811   constructor_elements = 0;
5812   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5813     {
5814       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5815       /* Skip any nameless bit fields at the beginning.  */
5816       while (constructor_unfilled_fields != 0
5817              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5818              && DECL_NAME (constructor_unfilled_fields) == 0)
5819         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5820
5821     }
5822   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5823     {
5824       if (TYPE_DOMAIN (constructor_type))
5825         constructor_unfilled_index
5826             = convert (bitsizetype,
5827                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5828       else
5829         constructor_unfilled_index = bitsize_zero_node;
5830     }
5831   constructor_incremental = 0;
5832 }
5833
5834 /* Build AVL tree from a string constant.  */
5835
5836 static void
5837 set_nonincremental_init_from_string (tree str)
5838 {
5839   tree value, purpose, type;
5840   HOST_WIDE_INT val[2];
5841   const char *p, *end;
5842   int byte, wchar_bytes, charwidth, bitpos;
5843
5844   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5845
5846   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5847       == TYPE_PRECISION (char_type_node))
5848     wchar_bytes = 1;
5849   else
5850     {
5851       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5852                   == TYPE_PRECISION (wchar_type_node));
5853       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5854     }
5855   charwidth = TYPE_PRECISION (char_type_node);
5856   type = TREE_TYPE (constructor_type);
5857   p = TREE_STRING_POINTER (str);
5858   end = p + TREE_STRING_LENGTH (str);
5859
5860   for (purpose = bitsize_zero_node;
5861        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5862        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5863     {
5864       if (wchar_bytes == 1)
5865         {
5866           val[1] = (unsigned char) *p++;
5867           val[0] = 0;
5868         }
5869       else
5870         {
5871           val[0] = 0;
5872           val[1] = 0;
5873           for (byte = 0; byte < wchar_bytes; byte++)
5874             {
5875               if (BYTES_BIG_ENDIAN)
5876                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5877               else
5878                 bitpos = byte * charwidth;
5879               val[bitpos < HOST_BITS_PER_WIDE_INT]
5880                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5881                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5882             }
5883         }
5884
5885       if (!TYPE_UNSIGNED (type))
5886         {
5887           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5888           if (bitpos < HOST_BITS_PER_WIDE_INT)
5889             {
5890               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5891                 {
5892                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5893                   val[0] = -1;
5894                 }
5895             }
5896           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5897             {
5898               if (val[1] < 0)
5899                 val[0] = -1;
5900             }
5901           else if (val[0] & (((HOST_WIDE_INT) 1)
5902                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5903             val[0] |= ((HOST_WIDE_INT) -1)
5904                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5905         }
5906
5907       value = build_int_cst_wide (type, val[1], val[0]);
5908       add_pending_init (purpose, value);
5909     }
5910
5911   constructor_incremental = 0;
5912 }
5913
5914 /* Return value of FIELD in pending initializer or zero if the field was
5915    not initialized yet.  */
5916
5917 static tree
5918 find_init_member (tree field)
5919 {
5920   struct init_node *p;
5921
5922   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5923     {
5924       if (constructor_incremental
5925           && tree_int_cst_lt (field, constructor_unfilled_index))
5926         set_nonincremental_init ();
5927
5928       p = constructor_pending_elts;
5929       while (p)
5930         {
5931           if (tree_int_cst_lt (field, p->purpose))
5932             p = p->left;
5933           else if (tree_int_cst_lt (p->purpose, field))
5934             p = p->right;
5935           else
5936             return p->value;
5937         }
5938     }
5939   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5940     {
5941       tree bitpos = bit_position (field);
5942
5943       if (constructor_incremental
5944           && (!constructor_unfilled_fields
5945               || tree_int_cst_lt (bitpos,
5946                                   bit_position (constructor_unfilled_fields))))
5947         set_nonincremental_init ();
5948
5949       p = constructor_pending_elts;
5950       while (p)
5951         {
5952           if (field == p->purpose)
5953             return p->value;
5954           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5955             p = p->left;
5956           else
5957             p = p->right;
5958         }
5959     }
5960   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5961     {
5962       if (!VEC_empty (constructor_elt, constructor_elements)
5963           && (VEC_last (constructor_elt, constructor_elements)->index
5964               == field))
5965         return VEC_last (constructor_elt, constructor_elements)->value;
5966     }
5967   return 0;
5968 }
5969
5970 /* "Output" the next constructor element.
5971    At top level, really output it to assembler code now.
5972    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5973    TYPE is the data type that the containing data type wants here.
5974    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5975    If VALUE is a string constant, STRICT_STRING is true if it is
5976    unparenthesized or we should not warn here for it being parenthesized.
5977    For other types of VALUE, STRICT_STRING is not used.
5978
5979    PENDING if non-nil means output pending elements that belong
5980    right after this element.  (PENDING is normally 1;
5981    it is 0 while outputting pending elements, to avoid recursion.)  */
5982
5983 static void
5984 output_init_element (tree value, bool strict_string, tree type, tree field,
5985                      int pending)
5986 {
5987   constructor_elt *celt;
5988
5989   if (type == error_mark_node || value == error_mark_node)
5990     {
5991       constructor_erroneous = 1;
5992       return;
5993     }
5994   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5995       && (TREE_CODE (value) == STRING_CST
5996           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5997       && !(TREE_CODE (value) == STRING_CST
5998            && TREE_CODE (type) == ARRAY_TYPE
5999            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6000       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6001                      TYPE_MAIN_VARIANT (type)))
6002     value = array_to_pointer_conversion (value);
6003
6004   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6005       && require_constant_value && !flag_isoc99 && pending)
6006     {
6007       /* As an extension, allow initializing objects with static storage
6008          duration with compound literals (which are then treated just as
6009          the brace enclosed list they contain).  */
6010       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6011       value = DECL_INITIAL (decl);
6012     }
6013
6014   if (value == error_mark_node)
6015     constructor_erroneous = 1;
6016   else if (!TREE_CONSTANT (value))
6017     constructor_constant = 0;
6018   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6019            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6020                 || TREE_CODE (constructor_type) == UNION_TYPE)
6021                && DECL_C_BIT_FIELD (field)
6022                && TREE_CODE (value) != INTEGER_CST))
6023     constructor_simple = 0;
6024
6025   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6026     {
6027       if (require_constant_value)
6028         {
6029           error_init ("initializer element is not constant");
6030           value = error_mark_node;
6031         }
6032       else if (require_constant_elements)
6033         pedwarn ("initializer element is not computable at load time");
6034     }
6035
6036   /* If this field is empty (and not at the end of structure),
6037      don't do anything other than checking the initializer.  */
6038   if (field
6039       && (TREE_TYPE (field) == error_mark_node
6040           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6041               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6042               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6043                   || TREE_CHAIN (field)))))
6044     return;
6045
6046   value = digest_init (type, value, strict_string, require_constant_value);
6047   if (value == error_mark_node)
6048     {
6049       constructor_erroneous = 1;
6050       return;
6051     }
6052
6053   /* If this element doesn't come next in sequence,
6054      put it on constructor_pending_elts.  */
6055   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6056       && (!constructor_incremental
6057           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6058     {
6059       if (constructor_incremental
6060           && tree_int_cst_lt (field, constructor_unfilled_index))
6061         set_nonincremental_init ();
6062
6063       add_pending_init (field, value);
6064       return;
6065     }
6066   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6067            && (!constructor_incremental
6068                || field != constructor_unfilled_fields))
6069     {
6070       /* We do this for records but not for unions.  In a union,
6071          no matter which field is specified, it can be initialized
6072          right away since it starts at the beginning of the union.  */
6073       if (constructor_incremental)
6074         {
6075           if (!constructor_unfilled_fields)
6076             set_nonincremental_init ();
6077           else
6078             {
6079               tree bitpos, unfillpos;
6080
6081               bitpos = bit_position (field);
6082               unfillpos = bit_position (constructor_unfilled_fields);
6083
6084               if (tree_int_cst_lt (bitpos, unfillpos))
6085                 set_nonincremental_init ();
6086             }
6087         }
6088
6089       add_pending_init (field, value);
6090       return;
6091     }
6092   else if (TREE_CODE (constructor_type) == UNION_TYPE
6093            && !VEC_empty (constructor_elt, constructor_elements))
6094     {
6095       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6096                                        constructor_elements)->value))
6097         warning_init ("initialized field with side-effects overwritten");
6098
6099       /* We can have just one union field set.  */
6100       constructor_elements = 0;
6101     }
6102
6103   /* Otherwise, output this element either to
6104      constructor_elements or to the assembler file.  */
6105
6106   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6107   celt->index = field;
6108   celt->value = value;
6109
6110   /* Advance the variable that indicates sequential elements output.  */
6111   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6112     constructor_unfilled_index
6113       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6114                     bitsize_one_node);
6115   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6116     {
6117       constructor_unfilled_fields
6118         = TREE_CHAIN (constructor_unfilled_fields);
6119
6120       /* Skip any nameless bit fields.  */
6121       while (constructor_unfilled_fields != 0
6122              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6123              && DECL_NAME (constructor_unfilled_fields) == 0)
6124         constructor_unfilled_fields =
6125           TREE_CHAIN (constructor_unfilled_fields);
6126     }
6127   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6128     constructor_unfilled_fields = 0;
6129
6130   /* Now output any pending elements which have become next.  */
6131   if (pending)
6132     output_pending_init_elements (0);
6133 }
6134
6135 /* Output any pending elements which have become next.
6136    As we output elements, constructor_unfilled_{fields,index}
6137    advances, which may cause other elements to become next;
6138    if so, they too are output.
6139
6140    If ALL is 0, we return when there are
6141    no more pending elements to output now.
6142
6143    If ALL is 1, we output space as necessary so that
6144    we can output all the pending elements.  */
6145
6146 static void
6147 output_pending_init_elements (int all)
6148 {
6149   struct init_node *elt = constructor_pending_elts;
6150   tree next;
6151
6152  retry:
6153
6154   /* Look through the whole pending tree.
6155      If we find an element that should be output now,
6156      output it.  Otherwise, set NEXT to the element
6157      that comes first among those still pending.  */
6158
6159   next = 0;
6160   while (elt)
6161     {
6162       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6163         {
6164           if (tree_int_cst_equal (elt->purpose,
6165                                   constructor_unfilled_index))
6166             output_init_element (elt->value, true,
6167                                  TREE_TYPE (constructor_type),
6168                                  constructor_unfilled_index, 0);
6169           else if (tree_int_cst_lt (constructor_unfilled_index,
6170                                     elt->purpose))
6171             {
6172               /* Advance to the next smaller node.  */
6173               if (elt->left)
6174                 elt = elt->left;
6175               else
6176                 {
6177                   /* We have reached the smallest node bigger than the
6178                      current unfilled index.  Fill the space first.  */
6179                   next = elt->purpose;
6180                   break;
6181                 }
6182             }
6183           else
6184             {
6185               /* Advance to the next bigger node.  */
6186               if (elt->right)
6187                 elt = elt->right;
6188               else
6189                 {
6190                   /* We have reached the biggest node in a subtree.  Find
6191                      the parent of it, which is the next bigger node.  */
6192                   while (elt->parent && elt->parent->right == elt)
6193                     elt = elt->parent;
6194                   elt = elt->parent;
6195                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6196                                               elt->purpose))
6197                     {
6198                       next = elt->purpose;
6199                       break;
6200                     }
6201                 }
6202             }
6203         }
6204       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6205                || TREE_CODE (constructor_type) == UNION_TYPE)
6206         {
6207           tree ctor_unfilled_bitpos, elt_bitpos;
6208
6209           /* If the current record is complete we are done.  */
6210           if (constructor_unfilled_fields == 0)
6211             break;
6212
6213           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6214           elt_bitpos = bit_position (elt->purpose);
6215           /* We can't compare fields here because there might be empty
6216              fields in between.  */
6217           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6218             {
6219               constructor_unfilled_fields = elt->purpose;
6220               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6221                                    elt->purpose, 0);
6222             }
6223           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6224             {
6225               /* Advance to the next smaller node.  */
6226               if (elt->left)
6227                 elt = elt->left;
6228               else
6229                 {
6230                   /* We have reached the smallest node bigger than the
6231                      current unfilled field.  Fill the space first.  */
6232                   next = elt->purpose;
6233                   break;
6234                 }
6235             }
6236           else
6237             {
6238               /* Advance to the next bigger node.  */
6239               if (elt->right)
6240                 elt = elt->right;
6241               else
6242                 {
6243                   /* We have reached the biggest node in a subtree.  Find
6244                      the parent of it, which is the next bigger node.  */
6245                   while (elt->parent && elt->parent->right == elt)
6246                     elt = elt->parent;
6247                   elt = elt->parent;
6248                   if (elt
6249                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6250                                            bit_position (elt->purpose))))
6251                     {
6252                       next = elt->purpose;
6253                       break;
6254                     }
6255                 }
6256             }
6257         }
6258     }
6259
6260   /* Ordinarily return, but not if we want to output all
6261      and there are elements left.  */
6262   if (!(all && next != 0))
6263     return;
6264
6265   /* If it's not incremental, just skip over the gap, so that after
6266      jumping to retry we will output the next successive element.  */
6267   if (TREE_CODE (constructor_type) == RECORD_TYPE
6268       || TREE_CODE (constructor_type) == UNION_TYPE)
6269     constructor_unfilled_fields = next;
6270   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6271     constructor_unfilled_index = next;
6272
6273   /* ELT now points to the node in the pending tree with the next
6274      initializer to output.  */
6275   goto retry;
6276 }
6277 \f
6278 /* Add one non-braced element to the current constructor level.
6279    This adjusts the current position within the constructor's type.
6280    This may also start or terminate implicit levels
6281    to handle a partly-braced initializer.
6282
6283    Once this has found the correct level for the new element,
6284    it calls output_init_element.  */
6285
6286 void
6287 process_init_element (struct c_expr value)
6288 {
6289   tree orig_value = value.value;
6290   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6291   bool strict_string = value.original_code == STRING_CST;
6292
6293   designator_depth = 0;
6294   designator_erroneous = 0;
6295
6296   /* Handle superfluous braces around string cst as in
6297      char x[] = {"foo"}; */
6298   if (string_flag
6299       && constructor_type
6300       && TREE_CODE (constructor_type) == ARRAY_TYPE
6301       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6302       && integer_zerop (constructor_unfilled_index))
6303     {
6304       if (constructor_stack->replacement_value.value)
6305         error_init ("excess elements in char array initializer");
6306       constructor_stack->replacement_value = value;
6307       return;
6308     }
6309
6310   if (constructor_stack->replacement_value.value != 0)
6311     {
6312       error_init ("excess elements in struct initializer");
6313       return;
6314     }
6315
6316   /* Ignore elements of a brace group if it is entirely superfluous
6317      and has already been diagnosed.  */
6318   if (constructor_type == 0)
6319     return;
6320
6321   /* If we've exhausted any levels that didn't have braces,
6322      pop them now.  */
6323   while (constructor_stack->implicit)
6324     {
6325       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6326            || TREE_CODE (constructor_type) == UNION_TYPE)
6327           && constructor_fields == 0)
6328         process_init_element (pop_init_level (1));
6329       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6330                && (constructor_max_index == 0
6331                    || tree_int_cst_lt (constructor_max_index,
6332                                        constructor_index)))
6333         process_init_element (pop_init_level (1));
6334       else
6335         break;
6336     }
6337
6338   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6339   if (constructor_range_stack)
6340     {
6341       /* If value is a compound literal and we'll be just using its
6342          content, don't put it into a SAVE_EXPR.  */
6343       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6344           || !require_constant_value
6345           || flag_isoc99)
6346         value.value = save_expr (value.value);
6347     }
6348
6349   while (1)
6350     {
6351       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6352         {
6353           tree fieldtype;
6354           enum tree_code fieldcode;
6355
6356           if (constructor_fields == 0)
6357             {
6358               pedwarn_init ("excess elements in struct initializer");
6359               break;
6360             }
6361
6362           fieldtype = TREE_TYPE (constructor_fields);
6363           if (fieldtype != error_mark_node)
6364             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6365           fieldcode = TREE_CODE (fieldtype);
6366
6367           /* Error for non-static initialization of a flexible array member.  */
6368           if (fieldcode == ARRAY_TYPE
6369               && !require_constant_value
6370               && TYPE_SIZE (fieldtype) == NULL_TREE
6371               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6372             {
6373               error_init ("non-static initialization of a flexible array member");
6374               break;
6375             }
6376
6377           /* Accept a string constant to initialize a subarray.  */
6378           if (value.value != 0
6379               && fieldcode == ARRAY_TYPE
6380               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6381               && string_flag)
6382             value.value = orig_value;
6383           /* Otherwise, if we have come to a subaggregate,
6384              and we don't have an element of its type, push into it.  */
6385           else if (value.value != 0
6386                    && value.value != error_mark_node
6387                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6388                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6389                        || fieldcode == UNION_TYPE))
6390             {
6391               push_init_level (1);
6392               continue;
6393             }
6394
6395           if (value.value)
6396             {
6397               push_member_name (constructor_fields);
6398               output_init_element (value.value, strict_string,
6399                                    fieldtype, constructor_fields, 1);
6400               RESTORE_SPELLING_DEPTH (constructor_depth);
6401             }
6402           else
6403             /* Do the bookkeeping for an element that was
6404                directly output as a constructor.  */
6405             {
6406               /* For a record, keep track of end position of last field.  */
6407               if (DECL_SIZE (constructor_fields))
6408                 constructor_bit_index
6409                   = size_binop (PLUS_EXPR,
6410                                 bit_position (constructor_fields),
6411                                 DECL_SIZE (constructor_fields));
6412
6413               /* If the current field was the first one not yet written out,
6414                  it isn't now, so update.  */
6415               if (constructor_unfilled_fields == constructor_fields)
6416                 {
6417                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6418                   /* Skip any nameless bit fields.  */
6419                   while (constructor_unfilled_fields != 0
6420                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6421                          && DECL_NAME (constructor_unfilled_fields) == 0)
6422                     constructor_unfilled_fields =
6423                       TREE_CHAIN (constructor_unfilled_fields);
6424                 }
6425             }
6426
6427           constructor_fields = TREE_CHAIN (constructor_fields);
6428           /* Skip any nameless bit fields at the beginning.  */
6429           while (constructor_fields != 0
6430                  && DECL_C_BIT_FIELD (constructor_fields)
6431                  && DECL_NAME (constructor_fields) == 0)
6432             constructor_fields = TREE_CHAIN (constructor_fields);
6433         }
6434       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6435         {
6436           tree fieldtype;
6437           enum tree_code fieldcode;
6438
6439           if (constructor_fields == 0)
6440             {
6441               pedwarn_init ("excess elements in union initializer");
6442               break;
6443             }
6444
6445           fieldtype = TREE_TYPE (constructor_fields);
6446           if (fieldtype != error_mark_node)
6447             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6448           fieldcode = TREE_CODE (fieldtype);
6449
6450           /* Warn that traditional C rejects initialization of unions.
6451              We skip the warning if the value is zero.  This is done
6452              under the assumption that the zero initializer in user
6453              code appears conditioned on e.g. __STDC__ to avoid
6454              "missing initializer" warnings and relies on default
6455              initialization to zero in the traditional C case.
6456              We also skip the warning if the initializer is designated,
6457              again on the assumption that this must be conditional on
6458              __STDC__ anyway (and we've already complained about the
6459              member-designator already).  */
6460           if (!in_system_header && !constructor_designated
6461               && !(value.value && (integer_zerop (value.value)
6462                                    || real_zerop (value.value))))
6463             warning (OPT_Wtraditional, "traditional C rejects initialization "
6464                      "of unions");
6465
6466           /* Accept a string constant to initialize a subarray.  */
6467           if (value.value != 0
6468               && fieldcode == ARRAY_TYPE
6469               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6470               && string_flag)
6471             value.value = orig_value;
6472           /* Otherwise, if we have come to a subaggregate,
6473              and we don't have an element of its type, push into it.  */
6474           else if (value.value != 0
6475                    && value.value != error_mark_node
6476                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6477                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6478                        || fieldcode == UNION_TYPE))
6479             {
6480               push_init_level (1);
6481               continue;
6482             }
6483
6484           if (value.value)
6485             {
6486               push_member_name (constructor_fields);
6487               output_init_element (value.value, strict_string,
6488                                    fieldtype, constructor_fields, 1);
6489               RESTORE_SPELLING_DEPTH (constructor_depth);
6490             }
6491           else
6492             /* Do the bookkeeping for an element that was
6493                directly output as a constructor.  */
6494             {
6495               constructor_bit_index = DECL_SIZE (constructor_fields);
6496               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6497             }
6498
6499           constructor_fields = 0;
6500         }
6501       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6502         {
6503           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6504           enum tree_code eltcode = TREE_CODE (elttype);
6505
6506           /* Accept a string constant to initialize a subarray.  */
6507           if (value.value != 0
6508               && eltcode == ARRAY_TYPE
6509               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6510               && string_flag)
6511             value.value = orig_value;
6512           /* Otherwise, if we have come to a subaggregate,
6513              and we don't have an element of its type, push into it.  */
6514           else if (value.value != 0
6515                    && value.value != error_mark_node
6516                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6517                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6518                        || eltcode == UNION_TYPE))
6519             {
6520               push_init_level (1);
6521               continue;
6522             }
6523
6524           if (constructor_max_index != 0
6525               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6526                   || integer_all_onesp (constructor_max_index)))
6527             {
6528               pedwarn_init ("excess elements in array initializer");
6529               break;
6530             }
6531
6532           /* Now output the actual element.  */
6533           if (value.value)
6534             {
6535               push_array_bounds (tree_low_cst (constructor_index, 0));
6536               output_init_element (value.value, strict_string,
6537                                    elttype, constructor_index, 1);
6538               RESTORE_SPELLING_DEPTH (constructor_depth);
6539             }
6540
6541           constructor_index
6542             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6543
6544           if (!value.value)
6545             /* If we are doing the bookkeeping for an element that was
6546                directly output as a constructor, we must update
6547                constructor_unfilled_index.  */
6548             constructor_unfilled_index = constructor_index;
6549         }
6550       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6551         {
6552           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6553
6554          /* Do a basic check of initializer size.  Note that vectors
6555             always have a fixed size derived from their type.  */
6556           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6557             {
6558               pedwarn_init ("excess elements in vector initializer");
6559               break;
6560             }
6561
6562           /* Now output the actual element.  */
6563           if (value.value)
6564             output_init_element (value.value, strict_string,
6565                                  elttype, constructor_index, 1);
6566
6567           constructor_index
6568             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6569
6570           if (!value.value)
6571             /* If we are doing the bookkeeping for an element that was
6572                directly output as a constructor, we must update
6573                constructor_unfilled_index.  */
6574             constructor_unfilled_index = constructor_index;
6575         }
6576
6577       /* Handle the sole element allowed in a braced initializer
6578          for a scalar variable.  */
6579       else if (constructor_type != error_mark_node
6580                && constructor_fields == 0)
6581         {
6582           pedwarn_init ("excess elements in scalar initializer");
6583           break;
6584         }
6585       else
6586         {
6587           if (value.value)
6588             output_init_element (value.value, strict_string,
6589                                  constructor_type, NULL_TREE, 1);
6590           constructor_fields = 0;
6591         }
6592
6593       /* Handle range initializers either at this level or anywhere higher
6594          in the designator stack.  */
6595       if (constructor_range_stack)
6596         {
6597           struct constructor_range_stack *p, *range_stack;
6598           int finish = 0;
6599
6600           range_stack = constructor_range_stack;
6601           constructor_range_stack = 0;
6602           while (constructor_stack != range_stack->stack)
6603             {
6604               gcc_assert (constructor_stack->implicit);
6605               process_init_element (pop_init_level (1));
6606             }
6607           for (p = range_stack;
6608                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6609                p = p->prev)
6610             {
6611               gcc_assert (constructor_stack->implicit);
6612               process_init_element (pop_init_level (1));
6613             }
6614
6615           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6616           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6617             finish = 1;
6618
6619           while (1)
6620             {
6621               constructor_index = p->index;
6622               constructor_fields = p->fields;
6623               if (finish && p->range_end && p->index == p->range_start)
6624                 {
6625                   finish = 0;
6626                   p->prev = 0;
6627                 }
6628               p = p->next;
6629               if (!p)
6630                 break;
6631               push_init_level (2);
6632               p->stack = constructor_stack;
6633               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6634                 p->index = p->range_start;
6635             }
6636
6637           if (!finish)
6638             constructor_range_stack = range_stack;
6639           continue;
6640         }
6641
6642       break;
6643     }
6644
6645   constructor_range_stack = 0;
6646 }
6647 \f
6648 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6649    (guaranteed to be 'volatile' or null) and ARGS (represented using
6650    an ASM_EXPR node).  */
6651 tree
6652 build_asm_stmt (tree cv_qualifier, tree args)
6653 {
6654   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6655     ASM_VOLATILE_P (args) = 1;
6656   return add_stmt (args);
6657 }
6658
6659 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6660    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6661    SIMPLE indicates whether there was anything at all after the
6662    string in the asm expression -- asm("blah") and asm("blah" : )
6663    are subtly different.  We use a ASM_EXPR node to represent this.  */
6664 tree
6665 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6666                 bool simple)
6667 {
6668   tree tail;
6669   tree args;
6670   int i;
6671   const char *constraint;
6672   const char **oconstraints;
6673   bool allows_mem, allows_reg, is_inout;
6674   int ninputs, noutputs;
6675
6676   ninputs = list_length (inputs);
6677   noutputs = list_length (outputs);
6678   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6679
6680   string = resolve_asm_operand_names (string, outputs, inputs);
6681
6682   /* Remove output conversions that change the type but not the mode.  */
6683   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6684     {
6685       tree output = TREE_VALUE (tail);
6686
6687       /* ??? Really, this should not be here.  Users should be using a
6688          proper lvalue, dammit.  But there's a long history of using casts
6689          in the output operands.  In cases like longlong.h, this becomes a
6690          primitive form of typechecking -- if the cast can be removed, then
6691          the output operand had a type of the proper width; otherwise we'll
6692          get an error.  Gross, but ...  */
6693       STRIP_NOPS (output);
6694
6695       if (!lvalue_or_else (output, lv_asm))
6696         output = error_mark_node;
6697
6698       if (output != error_mark_node
6699           && (TREE_READONLY (output)
6700               || TYPE_READONLY (TREE_TYPE (output))
6701               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6702                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6703                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6704         readonly_error (output, lv_asm);
6705
6706       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6707       oconstraints[i] = constraint;
6708
6709       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6710                                    &allows_mem, &allows_reg, &is_inout))
6711         {
6712           /* If the operand is going to end up in memory,
6713              mark it addressable.  */
6714           if (!allows_reg && !c_mark_addressable (output))
6715             output = error_mark_node;
6716         }
6717       else
6718         output = error_mark_node;
6719
6720       TREE_VALUE (tail) = output;
6721     }
6722
6723   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6724     {
6725       tree input;
6726
6727       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6728       input = TREE_VALUE (tail);
6729
6730       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6731                                   oconstraints, &allows_mem, &allows_reg))
6732         {
6733           /* If the operand is going to end up in memory,
6734              mark it addressable.  */
6735           if (!allows_reg && allows_mem)
6736             {
6737               /* Strip the nops as we allow this case.  FIXME, this really
6738                  should be rejected or made deprecated.  */
6739               STRIP_NOPS (input);
6740               if (!c_mark_addressable (input))
6741                 input = error_mark_node;
6742           }
6743         }
6744       else
6745         input = error_mark_node;
6746
6747       TREE_VALUE (tail) = input;
6748     }
6749
6750   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6751
6752   /* asm statements without outputs, including simple ones, are treated
6753      as volatile.  */
6754   ASM_INPUT_P (args) = simple;
6755   ASM_VOLATILE_P (args) = (noutputs == 0);
6756
6757   return args;
6758 }
6759 \f
6760 /* Generate a goto statement to LABEL.  */
6761
6762 tree
6763 c_finish_goto_label (tree label)
6764 {
6765   tree decl = lookup_label (label);
6766   if (!decl)
6767     return NULL_TREE;
6768
6769   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6770     {
6771       error ("jump into statement expression");
6772       return NULL_TREE;
6773     }
6774
6775   if (C_DECL_UNJUMPABLE_VM (decl))
6776     {
6777       error ("jump into scope of identifier with variably modified type");
6778       return NULL_TREE;
6779     }
6780
6781   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6782     {
6783       /* No jump from outside this statement expression context, so
6784          record that there is a jump from within this context.  */
6785       struct c_label_list *nlist;
6786       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6787       nlist->next = label_context_stack_se->labels_used;
6788       nlist->label = decl;
6789       label_context_stack_se->labels_used = nlist;
6790     }
6791
6792   if (!C_DECL_UNDEFINABLE_VM (decl))
6793     {
6794       /* No jump from outside this context context of identifiers with
6795          variably modified type, so record that there is a jump from
6796          within this context.  */
6797       struct c_label_list *nlist;
6798       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6799       nlist->next = label_context_stack_vm->labels_used;
6800       nlist->label = decl;
6801       label_context_stack_vm->labels_used = nlist;
6802     }
6803
6804   TREE_USED (decl) = 1;
6805   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6806 }
6807
6808 /* Generate a computed goto statement to EXPR.  */
6809
6810 tree
6811 c_finish_goto_ptr (tree expr)
6812 {
6813   if (pedantic)
6814     pedwarn ("ISO C forbids %<goto *expr;%>");
6815   expr = convert (ptr_type_node, expr);
6816   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6817 }
6818
6819 /* Generate a C `return' statement.  RETVAL is the expression for what
6820    to return, or a null pointer for `return;' with no value.  */
6821
6822 tree
6823 c_finish_return (tree retval)
6824 {
6825   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6826   bool no_warning = false;
6827
6828   if (TREE_THIS_VOLATILE (current_function_decl))
6829     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6830
6831   if (!retval)
6832     {
6833       current_function_returns_null = 1;
6834       if ((warn_return_type || flag_isoc99)
6835           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6836         {
6837           pedwarn_c99 ("%<return%> with no value, in "
6838                        "function returning non-void");
6839           no_warning = true;
6840         }
6841     }
6842   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6843     {
6844       current_function_returns_null = 1;
6845       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6846         pedwarn ("%<return%> with a value, in function returning void");
6847     }
6848   else
6849     {
6850       tree t = convert_for_assignment (valtype, retval, ic_return,
6851                                        NULL_TREE, NULL_TREE, 0);
6852       tree res = DECL_RESULT (current_function_decl);
6853       tree inner;
6854
6855       current_function_returns_value = 1;
6856       if (t == error_mark_node)
6857         return NULL_TREE;
6858
6859       inner = t = convert (TREE_TYPE (res), t);
6860
6861       /* Strip any conversions, additions, and subtractions, and see if
6862          we are returning the address of a local variable.  Warn if so.  */
6863       while (1)
6864         {
6865           switch (TREE_CODE (inner))
6866             {
6867             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6868             case PLUS_EXPR:
6869               inner = TREE_OPERAND (inner, 0);
6870               continue;
6871
6872             case MINUS_EXPR:
6873               /* If the second operand of the MINUS_EXPR has a pointer
6874                  type (or is converted from it), this may be valid, so
6875                  don't give a warning.  */
6876               {
6877                 tree op1 = TREE_OPERAND (inner, 1);
6878
6879                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6880                        && (TREE_CODE (op1) == NOP_EXPR
6881                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6882                            || TREE_CODE (op1) == CONVERT_EXPR))
6883                   op1 = TREE_OPERAND (op1, 0);
6884
6885                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6886                   break;
6887
6888                 inner = TREE_OPERAND (inner, 0);
6889                 continue;
6890               }
6891
6892             case ADDR_EXPR:
6893               inner = TREE_OPERAND (inner, 0);
6894
6895               while (REFERENCE_CLASS_P (inner)
6896                      && TREE_CODE (inner) != INDIRECT_REF)
6897                 inner = TREE_OPERAND (inner, 0);
6898
6899               if (DECL_P (inner)
6900                   && !DECL_EXTERNAL (inner)
6901                   && !TREE_STATIC (inner)
6902                   && DECL_CONTEXT (inner) == current_function_decl)
6903                 warning (0, "function returns address of local variable");
6904               break;
6905
6906             default:
6907               break;
6908             }
6909
6910           break;
6911         }
6912
6913       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6914     }
6915
6916   ret_stmt = build_stmt (RETURN_EXPR, retval);
6917   TREE_NO_WARNING (ret_stmt) |= no_warning;
6918   return add_stmt (ret_stmt);
6919 }
6920 \f
6921 struct c_switch {
6922   /* The SWITCH_EXPR being built.  */
6923   tree switch_expr;
6924
6925   /* The original type of the testing expression, i.e. before the
6926      default conversion is applied.  */
6927   tree orig_type;
6928
6929   /* A splay-tree mapping the low element of a case range to the high
6930      element, or NULL_TREE if there is no high element.  Used to
6931      determine whether or not a new case label duplicates an old case
6932      label.  We need a tree, rather than simply a hash table, because
6933      of the GNU case range extension.  */
6934   splay_tree cases;
6935
6936   /* Number of nested statement expressions within this switch
6937      statement; if nonzero, case and default labels may not
6938      appear.  */
6939   unsigned int blocked_stmt_expr;
6940
6941   /* Scope of outermost declarations of identifiers with variably
6942      modified type within this switch statement; if nonzero, case and
6943      default labels may not appear.  */
6944   unsigned int blocked_vm;
6945
6946   /* The next node on the stack.  */
6947   struct c_switch *next;
6948 };
6949
6950 /* A stack of the currently active switch statements.  The innermost
6951    switch statement is on the top of the stack.  There is no need to
6952    mark the stack for garbage collection because it is only active
6953    during the processing of the body of a function, and we never
6954    collect at that point.  */
6955
6956 struct c_switch *c_switch_stack;
6957
6958 /* Start a C switch statement, testing expression EXP.  Return the new
6959    SWITCH_EXPR.  */
6960
6961 tree
6962 c_start_case (tree exp)
6963 {
6964   enum tree_code code;
6965   tree type, orig_type = error_mark_node;
6966   struct c_switch *cs;
6967
6968   if (exp != error_mark_node)
6969     {
6970       code = TREE_CODE (TREE_TYPE (exp));
6971       orig_type = TREE_TYPE (exp);
6972
6973       if (!INTEGRAL_TYPE_P (orig_type)
6974           && code != ERROR_MARK)
6975         {
6976           error ("switch quantity not an integer");
6977           exp = integer_zero_node;
6978           orig_type = error_mark_node;
6979         }
6980       else
6981         {
6982           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6983
6984           if (!in_system_header
6985               && (type == long_integer_type_node
6986                   || type == long_unsigned_type_node))
6987             warning (OPT_Wtraditional, "%<long%> switch expression not "
6988                      "converted to %<int%> in ISO C");
6989
6990           exp = default_conversion (exp);
6991           type = TREE_TYPE (exp);
6992         }
6993     }
6994
6995   /* Add this new SWITCH_EXPR to the stack.  */
6996   cs = XNEW (struct c_switch);
6997   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6998   cs->orig_type = orig_type;
6999   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7000   cs->blocked_stmt_expr = 0;
7001   cs->blocked_vm = 0;
7002   cs->next = c_switch_stack;
7003   c_switch_stack = cs;
7004
7005   return add_stmt (cs->switch_expr);
7006 }
7007
7008 /* Process a case label.  */
7009
7010 tree
7011 do_case (tree low_value, tree high_value)
7012 {
7013   tree label = NULL_TREE;
7014
7015   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7016       && !c_switch_stack->blocked_vm)
7017     {
7018       label = c_add_case_label (c_switch_stack->cases,
7019                                 SWITCH_COND (c_switch_stack->switch_expr),
7020                                 c_switch_stack->orig_type,
7021                                 low_value, high_value);
7022       if (label == error_mark_node)
7023         label = NULL_TREE;
7024     }
7025   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7026     {
7027       if (low_value)
7028         error ("case label in statement expression not containing "
7029                "enclosing switch statement");
7030       else
7031         error ("%<default%> label in statement expression not containing "
7032                "enclosing switch statement");
7033     }
7034   else if (c_switch_stack && c_switch_stack->blocked_vm)
7035     {
7036       if (low_value)
7037         error ("case label in scope of identifier with variably modified "
7038                "type not containing enclosing switch statement");
7039       else
7040         error ("%<default%> label in scope of identifier with variably "
7041                "modified type not containing enclosing switch statement");
7042     }
7043   else if (low_value)
7044     error ("case label not within a switch statement");
7045   else
7046     error ("%<default%> label not within a switch statement");
7047
7048   return label;
7049 }
7050
7051 /* Finish the switch statement.  */
7052
7053 void
7054 c_finish_case (tree body)
7055 {
7056   struct c_switch *cs = c_switch_stack;
7057   location_t switch_location;
7058
7059   SWITCH_BODY (cs->switch_expr) = body;
7060
7061   /* We must not be within a statement expression nested in the switch
7062      at this point; we might, however, be within the scope of an
7063      identifier with variably modified type nested in the switch.  */
7064   gcc_assert (!cs->blocked_stmt_expr);
7065
7066   /* Emit warnings as needed.  */
7067   if (EXPR_HAS_LOCATION (cs->switch_expr))
7068     switch_location = EXPR_LOCATION (cs->switch_expr);
7069   else
7070     switch_location = input_location;
7071   c_do_switch_warnings (cs->cases, switch_location,
7072                         TREE_TYPE (cs->switch_expr),
7073                         SWITCH_COND (cs->switch_expr));
7074
7075   /* Pop the stack.  */
7076   c_switch_stack = cs->next;
7077   splay_tree_delete (cs->cases);
7078   XDELETE (cs);
7079 }
7080 \f
7081 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7082    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7083    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7084    statement, and was not surrounded with parenthesis.  */
7085
7086 void
7087 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7088                   tree else_block, bool nested_if)
7089 {
7090   tree stmt;
7091
7092   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7093   if (warn_parentheses && nested_if && else_block == NULL)
7094     {
7095       tree inner_if = then_block;
7096
7097       /* We know from the grammar productions that there is an IF nested
7098          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7099          it might not be exactly THEN_BLOCK, but should be the last
7100          non-container statement within.  */
7101       while (1)
7102         switch (TREE_CODE (inner_if))
7103           {
7104           case COND_EXPR:
7105             goto found;
7106           case BIND_EXPR:
7107             inner_if = BIND_EXPR_BODY (inner_if);
7108             break;
7109           case STATEMENT_LIST:
7110             inner_if = expr_last (then_block);
7111             break;
7112           case TRY_FINALLY_EXPR:
7113           case TRY_CATCH_EXPR:
7114             inner_if = TREE_OPERAND (inner_if, 0);
7115             break;
7116           default:
7117             gcc_unreachable ();
7118           }
7119     found:
7120
7121       if (COND_EXPR_ELSE (inner_if))
7122          warning (OPT_Wparentheses,
7123                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7124                   &if_locus);
7125     }
7126
7127   /* Diagnose ";" via the special empty statement node that we create.  */
7128   if (extra_warnings)
7129     {
7130       tree *inner_then = &then_block, *inner_else = &else_block;
7131
7132       if (TREE_CODE (*inner_then) == STATEMENT_LIST
7133           && STATEMENT_LIST_TAIL (*inner_then))
7134         inner_then = &STATEMENT_LIST_TAIL (*inner_then)->stmt;
7135       if (*inner_else && TREE_CODE (*inner_else) == STATEMENT_LIST
7136           && STATEMENT_LIST_TAIL (*inner_else))
7137         inner_else = &STATEMENT_LIST_TAIL (*inner_else)->stmt;
7138
7139       if (TREE_CODE (*inner_then) == NOP_EXPR && !TREE_TYPE (*inner_then))
7140         {
7141           if (!*inner_else)
7142             warning (0, "%Hempty body in an if-statement",
7143                      EXPR_LOCUS (*inner_then));
7144
7145           *inner_then = alloc_stmt_list ();
7146         }
7147       if (*inner_else
7148           && TREE_CODE (*inner_else) == NOP_EXPR
7149           && !TREE_TYPE (*inner_else))
7150         {
7151           warning (0, "%Hempty body in an else-statement",
7152                    EXPR_LOCUS (*inner_else));
7153
7154           *inner_else = alloc_stmt_list ();
7155         }
7156     }
7157
7158   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7159   SET_EXPR_LOCATION (stmt, if_locus);
7160   add_stmt (stmt);
7161 }
7162
7163 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7164    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7165    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7166    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7167    the continue label.  Everything is allowed to be NULL.  */
7168
7169 void
7170 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7171                tree blab, tree clab, bool cond_is_first)
7172 {
7173   tree entry = NULL, exit = NULL, t;
7174
7175   /* If the condition is zero don't generate a loop construct.  */
7176   if (cond && integer_zerop (cond))
7177     {
7178       if (cond_is_first)
7179         {
7180           t = build_and_jump (&blab);
7181           SET_EXPR_LOCATION (t, start_locus);
7182           add_stmt (t);
7183         }
7184     }
7185   else
7186     {
7187       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7188
7189       /* If we have an exit condition, then we build an IF with gotos either
7190          out of the loop, or to the top of it.  If there's no exit condition,
7191          then we just build a jump back to the top.  */
7192       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7193
7194       if (cond && !integer_nonzerop (cond))
7195         {
7196           /* Canonicalize the loop condition to the end.  This means
7197              generating a branch to the loop condition.  Reuse the
7198              continue label, if possible.  */
7199           if (cond_is_first)
7200             {
7201               if (incr || !clab)
7202                 {
7203                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7204                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7205                 }
7206               else
7207                 t = build1 (GOTO_EXPR, void_type_node, clab);
7208               SET_EXPR_LOCATION (t, start_locus);
7209               add_stmt (t);
7210             }
7211
7212           t = build_and_jump (&blab);
7213           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7214           if (cond_is_first)
7215             SET_EXPR_LOCATION (exit, start_locus);
7216           else
7217             SET_EXPR_LOCATION (exit, input_location);
7218         }
7219
7220       add_stmt (top);
7221     }
7222
7223   if (body)
7224     add_stmt (body);
7225   if (clab)
7226     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7227   if (incr)
7228     add_stmt (incr);
7229   if (entry)
7230     add_stmt (entry);
7231   if (exit)
7232     add_stmt (exit);
7233   if (blab)
7234     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7235 }
7236
7237 tree
7238 c_finish_bc_stmt (tree *label_p, bool is_break)
7239 {
7240   bool skip;
7241   tree label = *label_p;
7242
7243   /* In switch statements break is sometimes stylistically used after
7244      a return statement.  This can lead to spurious warnings about
7245      control reaching the end of a non-void function when it is
7246      inlined.  Note that we are calling block_may_fallthru with
7247      language specific tree nodes; this works because
7248      block_may_fallthru returns true when given something it does not
7249      understand.  */
7250   skip = !block_may_fallthru (cur_stmt_list);
7251
7252   if (!label)
7253     {
7254       if (!skip)
7255         *label_p = label = create_artificial_label ();
7256     }
7257   else if (TREE_CODE (label) != LABEL_DECL)
7258     {
7259       if (is_break)
7260         error ("break statement not within loop or switch");
7261       else
7262         error ("continue statement not within a loop");
7263       return NULL_TREE;
7264     }
7265
7266   if (skip)
7267     return NULL_TREE;
7268
7269   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7270 }
7271
7272 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7273
7274 static void
7275 emit_side_effect_warnings (tree expr)
7276 {
7277   if (expr == error_mark_node)
7278     ;
7279   else if (!TREE_SIDE_EFFECTS (expr))
7280     {
7281       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7282         warning (0, "%Hstatement with no effect",
7283                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7284     }
7285   else if (warn_unused_value)
7286     warn_if_unused_value (expr, input_location);
7287 }
7288
7289 /* Process an expression as if it were a complete statement.  Emit
7290    diagnostics, but do not call ADD_STMT.  */
7291
7292 tree
7293 c_process_expr_stmt (tree expr)
7294 {
7295   if (!expr)
7296     return NULL_TREE;
7297
7298   if (warn_sequence_point)
7299     verify_sequence_points (expr);
7300
7301   if (TREE_TYPE (expr) != error_mark_node
7302       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7303       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7304     error ("expression statement has incomplete type");
7305
7306   /* If we're not processing a statement expression, warn about unused values.
7307      Warnings for statement expressions will be emitted later, once we figure
7308      out which is the result.  */
7309   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7310       && (extra_warnings || warn_unused_value))
7311     emit_side_effect_warnings (expr);
7312
7313   /* If the expression is not of a type to which we cannot assign a line
7314      number, wrap the thing in a no-op NOP_EXPR.  */
7315   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7316     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7317
7318   if (EXPR_P (expr))
7319     SET_EXPR_LOCATION (expr, input_location);
7320
7321   return expr;
7322 }
7323
7324 /* Emit an expression as a statement.  */
7325
7326 tree
7327 c_finish_expr_stmt (tree expr)
7328 {
7329   if (expr)
7330     return add_stmt (c_process_expr_stmt (expr));
7331   else
7332     return NULL;
7333 }
7334
7335 /* Do the opposite and emit a statement as an expression.  To begin,
7336    create a new binding level and return it.  */
7337
7338 tree
7339 c_begin_stmt_expr (void)
7340 {
7341   tree ret;
7342   struct c_label_context_se *nstack;
7343   struct c_label_list *glist;
7344
7345   /* We must force a BLOCK for this level so that, if it is not expanded
7346      later, there is a way to turn off the entire subtree of blocks that
7347      are contained in it.  */
7348   keep_next_level ();
7349   ret = c_begin_compound_stmt (true);
7350   if (c_switch_stack)
7351     {
7352       c_switch_stack->blocked_stmt_expr++;
7353       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7354     }
7355   for (glist = label_context_stack_se->labels_used;
7356        glist != NULL;
7357        glist = glist->next)
7358     {
7359       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7360     }
7361   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7362   nstack->labels_def = NULL;
7363   nstack->labels_used = NULL;
7364   nstack->next = label_context_stack_se;
7365   label_context_stack_se = nstack;
7366
7367   /* Mark the current statement list as belonging to a statement list.  */
7368   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7369
7370   return ret;
7371 }
7372
7373 tree
7374 c_finish_stmt_expr (tree body)
7375 {
7376   tree last, type, tmp, val;
7377   tree *last_p;
7378   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7379
7380   body = c_end_compound_stmt (body, true);
7381   if (c_switch_stack)
7382     {
7383       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7384       c_switch_stack->blocked_stmt_expr--;
7385     }
7386   /* It is no longer possible to jump to labels defined within this
7387      statement expression.  */
7388   for (dlist = label_context_stack_se->labels_def;
7389        dlist != NULL;
7390        dlist = dlist->next)
7391     {
7392       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7393     }
7394   /* It is again possible to define labels with a goto just outside
7395      this statement expression.  */
7396   for (glist = label_context_stack_se->next->labels_used;
7397        glist != NULL;
7398        glist = glist->next)
7399     {
7400       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7401       glist_prev = glist;
7402     }
7403   if (glist_prev != NULL)
7404     glist_prev->next = label_context_stack_se->labels_used;
7405   else
7406     label_context_stack_se->next->labels_used
7407       = label_context_stack_se->labels_used;
7408   label_context_stack_se = label_context_stack_se->next;
7409
7410   /* Locate the last statement in BODY.  See c_end_compound_stmt
7411      about always returning a BIND_EXPR.  */
7412   last_p = &BIND_EXPR_BODY (body);
7413   last = BIND_EXPR_BODY (body);
7414
7415  continue_searching:
7416   if (TREE_CODE (last) == STATEMENT_LIST)
7417     {
7418       tree_stmt_iterator i;
7419
7420       /* This can happen with degenerate cases like ({ }).  No value.  */
7421       if (!TREE_SIDE_EFFECTS (last))
7422         return body;
7423
7424       /* If we're supposed to generate side effects warnings, process
7425          all of the statements except the last.  */
7426       if (extra_warnings || warn_unused_value)
7427         {
7428           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7429             emit_side_effect_warnings (tsi_stmt (i));
7430         }
7431       else
7432         i = tsi_last (last);
7433       last_p = tsi_stmt_ptr (i);
7434       last = *last_p;
7435     }
7436
7437   /* If the end of the list is exception related, then the list was split
7438      by a call to push_cleanup.  Continue searching.  */
7439   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7440       || TREE_CODE (last) == TRY_CATCH_EXPR)
7441     {
7442       last_p = &TREE_OPERAND (last, 0);
7443       last = *last_p;
7444       goto continue_searching;
7445     }
7446
7447   /* In the case that the BIND_EXPR is not necessary, return the
7448      expression out from inside it.  */
7449   if (last == error_mark_node
7450       || (last == BIND_EXPR_BODY (body)
7451           && BIND_EXPR_VARS (body) == NULL))
7452     {
7453       /* Do not warn if the return value of a statement expression is
7454          unused.  */
7455       if (EXPR_P (last))
7456         TREE_NO_WARNING (last) = 1;
7457       return last;
7458     }
7459
7460   /* Extract the type of said expression.  */
7461   type = TREE_TYPE (last);
7462
7463   /* If we're not returning a value at all, then the BIND_EXPR that
7464      we already have is a fine expression to return.  */
7465   if (!type || VOID_TYPE_P (type))
7466     return body;
7467
7468   /* Now that we've located the expression containing the value, it seems
7469      silly to make voidify_wrapper_expr repeat the process.  Create a
7470      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7471   tmp = create_tmp_var_raw (type, NULL);
7472
7473   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7474      tree_expr_nonnegative_p giving up immediately.  */
7475   val = last;
7476   if (TREE_CODE (val) == NOP_EXPR
7477       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7478     val = TREE_OPERAND (val, 0);
7479
7480   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7481   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7482
7483   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7484 }
7485
7486 /* Begin the scope of an identifier of variably modified type, scope
7487    number SCOPE.  Jumping from outside this scope to inside it is not
7488    permitted.  */
7489
7490 void
7491 c_begin_vm_scope (unsigned int scope)
7492 {
7493   struct c_label_context_vm *nstack;
7494   struct c_label_list *glist;
7495
7496   gcc_assert (scope > 0);
7497   if (c_switch_stack && !c_switch_stack->blocked_vm)
7498     c_switch_stack->blocked_vm = scope;
7499   for (glist = label_context_stack_vm->labels_used;
7500        glist != NULL;
7501        glist = glist->next)
7502     {
7503       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7504     }
7505   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7506   nstack->labels_def = NULL;
7507   nstack->labels_used = NULL;
7508   nstack->scope = scope;
7509   nstack->next = label_context_stack_vm;
7510   label_context_stack_vm = nstack;
7511 }
7512
7513 /* End a scope which may contain identifiers of variably modified
7514    type, scope number SCOPE.  */
7515
7516 void
7517 c_end_vm_scope (unsigned int scope)
7518 {
7519   if (label_context_stack_vm == NULL)
7520     return;
7521   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7522     c_switch_stack->blocked_vm = 0;
7523   /* We may have a number of nested scopes of identifiers with
7524      variably modified type, all at this depth.  Pop each in turn.  */
7525   while (label_context_stack_vm->scope == scope)
7526     {
7527       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7528
7529       /* It is no longer possible to jump to labels defined within this
7530          scope.  */
7531       for (dlist = label_context_stack_vm->labels_def;
7532            dlist != NULL;
7533            dlist = dlist->next)
7534         {
7535           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7536         }
7537       /* It is again possible to define labels with a goto just outside
7538          this scope.  */
7539       for (glist = label_context_stack_vm->next->labels_used;
7540            glist != NULL;
7541            glist = glist->next)
7542         {
7543           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7544           glist_prev = glist;
7545         }
7546       if (glist_prev != NULL)
7547         glist_prev->next = label_context_stack_vm->labels_used;
7548       else
7549         label_context_stack_vm->next->labels_used
7550           = label_context_stack_vm->labels_used;
7551       label_context_stack_vm = label_context_stack_vm->next;
7552     }
7553 }
7554 \f
7555 /* Begin and end compound statements.  This is as simple as pushing
7556    and popping new statement lists from the tree.  */
7557
7558 tree
7559 c_begin_compound_stmt (bool do_scope)
7560 {
7561   tree stmt = push_stmt_list ();
7562   if (do_scope)
7563     push_scope ();
7564   return stmt;
7565 }
7566
7567 tree
7568 c_end_compound_stmt (tree stmt, bool do_scope)
7569 {
7570   tree block = NULL;
7571
7572   if (do_scope)
7573     {
7574       if (c_dialect_objc ())
7575         objc_clear_super_receiver ();
7576       block = pop_scope ();
7577     }
7578
7579   stmt = pop_stmt_list (stmt);
7580   stmt = c_build_bind_expr (block, stmt);
7581
7582   /* If this compound statement is nested immediately inside a statement
7583      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7584      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7585      STATEMENT_LISTs merge, and thus we can lose track of what statement
7586      was really last.  */
7587   if (cur_stmt_list
7588       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7589       && TREE_CODE (stmt) != BIND_EXPR)
7590     {
7591       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7592       TREE_SIDE_EFFECTS (stmt) = 1;
7593     }
7594
7595   return stmt;
7596 }
7597
7598 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7599    when the current scope is exited.  EH_ONLY is true when this is not
7600    meant to apply to normal control flow transfer.  */
7601
7602 void
7603 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7604 {
7605   enum tree_code code;
7606   tree stmt, list;
7607   bool stmt_expr;
7608
7609   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7610   stmt = build_stmt (code, NULL, cleanup);
7611   add_stmt (stmt);
7612   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7613   list = push_stmt_list ();
7614   TREE_OPERAND (stmt, 0) = list;
7615   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7616 }
7617 \f
7618 /* Build a binary-operation expression without default conversions.
7619    CODE is the kind of expression to build.
7620    This function differs from `build' in several ways:
7621    the data type of the result is computed and recorded in it,
7622    warnings are generated if arg data types are invalid,
7623    special handling for addition and subtraction of pointers is known,
7624    and some optimization is done (operations on narrow ints
7625    are done in the narrower type when that gives the same result).
7626    Constant folding is also done before the result is returned.
7627
7628    Note that the operands will never have enumeral types, or function
7629    or array types, because either they will have the default conversions
7630    performed or they have both just been converted to some other type in which
7631    the arithmetic is to be done.  */
7632
7633 tree
7634 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7635                  int convert_p)
7636 {
7637   tree type0, type1;
7638   enum tree_code code0, code1;
7639   tree op0, op1;
7640   const char *invalid_op_diag;
7641
7642   /* Expression code to give to the expression when it is built.
7643      Normally this is CODE, which is what the caller asked for,
7644      but in some special cases we change it.  */
7645   enum tree_code resultcode = code;
7646
7647   /* Data type in which the computation is to be performed.
7648      In the simplest cases this is the common type of the arguments.  */
7649   tree result_type = NULL;
7650
7651   /* Nonzero means operands have already been type-converted
7652      in whatever way is necessary.
7653      Zero means they need to be converted to RESULT_TYPE.  */
7654   int converted = 0;
7655
7656   /* Nonzero means create the expression with this type, rather than
7657      RESULT_TYPE.  */
7658   tree build_type = 0;
7659
7660   /* Nonzero means after finally constructing the expression
7661      convert it to this type.  */
7662   tree final_type = 0;
7663
7664   /* Nonzero if this is an operation like MIN or MAX which can
7665      safely be computed in short if both args are promoted shorts.
7666      Also implies COMMON.
7667      -1 indicates a bitwise operation; this makes a difference
7668      in the exact conditions for when it is safe to do the operation
7669      in a narrower mode.  */
7670   int shorten = 0;
7671
7672   /* Nonzero if this is a comparison operation;
7673      if both args are promoted shorts, compare the original shorts.
7674      Also implies COMMON.  */
7675   int short_compare = 0;
7676
7677   /* Nonzero if this is a right-shift operation, which can be computed on the
7678      original short and then promoted if the operand is a promoted short.  */
7679   int short_shift = 0;
7680
7681   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7682   int common = 0;
7683
7684   /* True means types are compatible as far as ObjC is concerned.  */
7685   bool objc_ok;
7686
7687   if (convert_p)
7688     {
7689       op0 = default_conversion (orig_op0);
7690       op1 = default_conversion (orig_op1);
7691     }
7692   else
7693     {
7694       op0 = orig_op0;
7695       op1 = orig_op1;
7696     }
7697
7698   type0 = TREE_TYPE (op0);
7699   type1 = TREE_TYPE (op1);
7700
7701   /* The expression codes of the data types of the arguments tell us
7702      whether the arguments are integers, floating, pointers, etc.  */
7703   code0 = TREE_CODE (type0);
7704   code1 = TREE_CODE (type1);
7705
7706   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7707   STRIP_TYPE_NOPS (op0);
7708   STRIP_TYPE_NOPS (op1);
7709
7710   /* If an error was already reported for one of the arguments,
7711      avoid reporting another error.  */
7712
7713   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7714     return error_mark_node;
7715
7716   if ((invalid_op_diag
7717        = targetm.invalid_binary_op (code, type0, type1)))
7718     {
7719       error (invalid_op_diag);
7720       return error_mark_node;
7721     }
7722
7723   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7724
7725   switch (code)
7726     {
7727     case PLUS_EXPR:
7728       /* Handle the pointer + int case.  */
7729       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7730         return pointer_int_sum (PLUS_EXPR, op0, op1);
7731       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7732         return pointer_int_sum (PLUS_EXPR, op1, op0);
7733       else
7734         common = 1;
7735       break;
7736
7737     case MINUS_EXPR:
7738       /* Subtraction of two similar pointers.
7739          We must subtract them as integers, then divide by object size.  */
7740       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7741           && comp_target_types (type0, type1))
7742         return pointer_diff (op0, op1);
7743       /* Handle pointer minus int.  Just like pointer plus int.  */
7744       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7745         return pointer_int_sum (MINUS_EXPR, op0, op1);
7746       else
7747         common = 1;
7748       break;
7749
7750     case MULT_EXPR:
7751       common = 1;
7752       break;
7753
7754     case TRUNC_DIV_EXPR:
7755     case CEIL_DIV_EXPR:
7756     case FLOOR_DIV_EXPR:
7757     case ROUND_DIV_EXPR:
7758     case EXACT_DIV_EXPR:
7759       /* Floating point division by zero is a legitimate way to obtain
7760          infinities and NaNs.  */
7761       if (skip_evaluation == 0 && integer_zerop (op1))
7762         warning (OPT_Wdiv_by_zero, "division by zero");
7763
7764       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7765            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7766           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7767               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7768         {
7769           enum tree_code tcode0 = code0, tcode1 = code1;
7770
7771           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7772             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7773           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7774             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7775
7776           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7777             resultcode = RDIV_EXPR;
7778           else
7779             /* Although it would be tempting to shorten always here, that
7780                loses on some targets, since the modulo instruction is
7781                undefined if the quotient can't be represented in the
7782                computation mode.  We shorten only if unsigned or if
7783                dividing by something we know != -1.  */
7784             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7785                        || (TREE_CODE (op1) == INTEGER_CST
7786                            && !integer_all_onesp (op1)));
7787           common = 1;
7788         }
7789       break;
7790
7791     case BIT_AND_EXPR:
7792     case BIT_IOR_EXPR:
7793     case BIT_XOR_EXPR:
7794       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7795         shorten = -1;
7796       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7797         common = 1;
7798       break;
7799
7800     case TRUNC_MOD_EXPR:
7801     case FLOOR_MOD_EXPR:
7802       if (skip_evaluation == 0 && integer_zerop (op1))
7803         warning (OPT_Wdiv_by_zero, "division by zero");
7804
7805       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7806         {
7807           /* Although it would be tempting to shorten always here, that loses
7808              on some targets, since the modulo instruction is undefined if the
7809              quotient can't be represented in the computation mode.  We shorten
7810              only if unsigned or if dividing by something we know != -1.  */
7811           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7812                      || (TREE_CODE (op1) == INTEGER_CST
7813                          && !integer_all_onesp (op1)));
7814           common = 1;
7815         }
7816       break;
7817
7818     case TRUTH_ANDIF_EXPR:
7819     case TRUTH_ORIF_EXPR:
7820     case TRUTH_AND_EXPR:
7821     case TRUTH_OR_EXPR:
7822     case TRUTH_XOR_EXPR:
7823       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7824            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7825           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7826               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7827         {
7828           /* Result of these operations is always an int,
7829              but that does not mean the operands should be
7830              converted to ints!  */
7831           result_type = integer_type_node;
7832           op0 = c_common_truthvalue_conversion (op0);
7833           op1 = c_common_truthvalue_conversion (op1);
7834           converted = 1;
7835         }
7836       break;
7837
7838       /* Shift operations: result has same type as first operand;
7839          always convert second operand to int.
7840          Also set SHORT_SHIFT if shifting rightward.  */
7841
7842     case RSHIFT_EXPR:
7843       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7844         {
7845           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7846             {
7847               if (tree_int_cst_sgn (op1) < 0)
7848                 warning (0, "right shift count is negative");
7849               else
7850                 {
7851                   if (!integer_zerop (op1))
7852                     short_shift = 1;
7853
7854                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7855                     warning (0, "right shift count >= width of type");
7856                 }
7857             }
7858
7859           /* Use the type of the value to be shifted.  */
7860           result_type = type0;
7861           /* Convert the shift-count to an integer, regardless of size
7862              of value being shifted.  */
7863           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7864             op1 = convert (integer_type_node, op1);
7865           /* Avoid converting op1 to result_type later.  */
7866           converted = 1;
7867         }
7868       break;
7869
7870     case LSHIFT_EXPR:
7871       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7872         {
7873           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7874             {
7875               if (tree_int_cst_sgn (op1) < 0)
7876                 warning (0, "left shift count is negative");
7877
7878               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7879                 warning (0, "left shift count >= width of type");
7880             }
7881
7882           /* Use the type of the value to be shifted.  */
7883           result_type = type0;
7884           /* Convert the shift-count to an integer, regardless of size
7885              of value being shifted.  */
7886           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7887             op1 = convert (integer_type_node, op1);
7888           /* Avoid converting op1 to result_type later.  */
7889           converted = 1;
7890         }
7891       break;
7892
7893     case EQ_EXPR:
7894     case NE_EXPR:
7895       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7896         warning (OPT_Wfloat_equal,
7897                  "comparing floating point with == or != is unsafe");
7898       /* Result of comparison is always int,
7899          but don't convert the args to int!  */
7900       build_type = integer_type_node;
7901       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7902            || code0 == COMPLEX_TYPE)
7903           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7904               || code1 == COMPLEX_TYPE))
7905         short_compare = 1;
7906       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7907         {
7908           tree tt0 = TREE_TYPE (type0);
7909           tree tt1 = TREE_TYPE (type1);
7910           /* Anything compares with void *.  void * compares with anything.
7911              Otherwise, the targets must be compatible
7912              and both must be object or both incomplete.  */
7913           if (comp_target_types (type0, type1))
7914             result_type = common_pointer_type (type0, type1);
7915           else if (VOID_TYPE_P (tt0))
7916             {
7917               /* op0 != orig_op0 detects the case of something
7918                  whose value is 0 but which isn't a valid null ptr const.  */
7919               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7920                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7921                 pedwarn ("ISO C forbids comparison of %<void *%>"
7922                          " with function pointer");
7923             }
7924           else if (VOID_TYPE_P (tt1))
7925             {
7926               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7927                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7928                 pedwarn ("ISO C forbids comparison of %<void *%>"
7929                          " with function pointer");
7930             }
7931           else
7932             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7933             if (!objc_ok)
7934               pedwarn ("comparison of distinct pointer types lacks a cast");
7935
7936           if (result_type == NULL_TREE)
7937             result_type = ptr_type_node;
7938         }
7939       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7940                && integer_zerop (op1))
7941         result_type = type0;
7942       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7943                && integer_zerop (op0))
7944         result_type = type1;
7945       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7946         {
7947           result_type = type0;
7948           pedwarn ("comparison between pointer and integer");
7949         }
7950       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7951         {
7952           result_type = type1;
7953           pedwarn ("comparison between pointer and integer");
7954         }
7955       break;
7956
7957     case LE_EXPR:
7958     case GE_EXPR:
7959     case LT_EXPR:
7960     case GT_EXPR:
7961       build_type = integer_type_node;
7962       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7963           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7964         short_compare = 1;
7965       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7966         {
7967           if (comp_target_types (type0, type1))
7968             {
7969               result_type = common_pointer_type (type0, type1);
7970               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7971                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7972                 pedwarn ("comparison of complete and incomplete pointers");
7973               else if (pedantic
7974                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7975                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7976             }
7977           else
7978             {
7979               result_type = ptr_type_node;
7980               pedwarn ("comparison of distinct pointer types lacks a cast");
7981             }
7982         }
7983       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7984                && integer_zerop (op1))
7985         {
7986           result_type = type0;
7987           if (pedantic || extra_warnings)
7988             pedwarn ("ordered comparison of pointer with integer zero");
7989         }
7990       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7991                && integer_zerop (op0))
7992         {
7993           result_type = type1;
7994           if (pedantic)
7995             pedwarn ("ordered comparison of pointer with integer zero");
7996         }
7997       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7998         {
7999           result_type = type0;
8000           pedwarn ("comparison between pointer and integer");
8001         }
8002       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8003         {
8004           result_type = type1;
8005           pedwarn ("comparison between pointer and integer");
8006         }
8007       break;
8008
8009     default:
8010       gcc_unreachable ();
8011     }
8012
8013   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8014     return error_mark_node;
8015
8016   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8017       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8018           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8019                                                     TREE_TYPE (type1))))
8020     {
8021       binary_op_error (code);
8022       return error_mark_node;
8023     }
8024
8025   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8026        || code0 == VECTOR_TYPE)
8027       &&
8028       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8029        || code1 == VECTOR_TYPE))
8030     {
8031       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8032
8033       if (shorten || common || short_compare)
8034         result_type = c_common_type (type0, type1);
8035
8036       /* For certain operations (which identify themselves by shorten != 0)
8037          if both args were extended from the same smaller type,
8038          do the arithmetic in that type and then extend.
8039
8040          shorten !=0 and !=1 indicates a bitwise operation.
8041          For them, this optimization is safe only if
8042          both args are zero-extended or both are sign-extended.
8043          Otherwise, we might change the result.
8044          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8045          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8046
8047       if (shorten && none_complex)
8048         {
8049           int unsigned0, unsigned1;
8050           tree arg0 = get_narrower (op0, &unsigned0);
8051           tree arg1 = get_narrower (op1, &unsigned1);
8052           /* UNS is 1 if the operation to be done is an unsigned one.  */
8053           int uns = TYPE_UNSIGNED (result_type);
8054           tree type;
8055
8056           final_type = result_type;
8057
8058           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8059              but it *requires* conversion to FINAL_TYPE.  */
8060
8061           if ((TYPE_PRECISION (TREE_TYPE (op0))
8062                == TYPE_PRECISION (TREE_TYPE (arg0)))
8063               && TREE_TYPE (op0) != final_type)
8064             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8065           if ((TYPE_PRECISION (TREE_TYPE (op1))
8066                == TYPE_PRECISION (TREE_TYPE (arg1)))
8067               && TREE_TYPE (op1) != final_type)
8068             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8069
8070           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8071
8072           /* For bitwise operations, signedness of nominal type
8073              does not matter.  Consider only how operands were extended.  */
8074           if (shorten == -1)
8075             uns = unsigned0;
8076
8077           /* Note that in all three cases below we refrain from optimizing
8078              an unsigned operation on sign-extended args.
8079              That would not be valid.  */
8080
8081           /* Both args variable: if both extended in same way
8082              from same width, do it in that width.
8083              Do it unsigned if args were zero-extended.  */
8084           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8085                < TYPE_PRECISION (result_type))
8086               && (TYPE_PRECISION (TREE_TYPE (arg1))
8087                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8088               && unsigned0 == unsigned1
8089               && (unsigned0 || !uns))
8090             result_type
8091               = c_common_signed_or_unsigned_type
8092               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8093           else if (TREE_CODE (arg0) == INTEGER_CST
8094                    && (unsigned1 || !uns)
8095                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8096                        < TYPE_PRECISION (result_type))
8097                    && (type
8098                        = c_common_signed_or_unsigned_type (unsigned1,
8099                                                            TREE_TYPE (arg1)),
8100                        int_fits_type_p (arg0, type)))
8101             result_type = type;
8102           else if (TREE_CODE (arg1) == INTEGER_CST
8103                    && (unsigned0 || !uns)
8104                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8105                        < TYPE_PRECISION (result_type))
8106                    && (type
8107                        = c_common_signed_or_unsigned_type (unsigned0,
8108                                                            TREE_TYPE (arg0)),
8109                        int_fits_type_p (arg1, type)))
8110             result_type = type;
8111         }
8112
8113       /* Shifts can be shortened if shifting right.  */
8114
8115       if (short_shift)
8116         {
8117           int unsigned_arg;
8118           tree arg0 = get_narrower (op0, &unsigned_arg);
8119
8120           final_type = result_type;
8121
8122           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8123             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8124
8125           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8126               /* We can shorten only if the shift count is less than the
8127                  number of bits in the smaller type size.  */
8128               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8129               /* We cannot drop an unsigned shift after sign-extension.  */
8130               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8131             {
8132               /* Do an unsigned shift if the operand was zero-extended.  */
8133               result_type
8134                 = c_common_signed_or_unsigned_type (unsigned_arg,
8135                                                     TREE_TYPE (arg0));
8136               /* Convert value-to-be-shifted to that type.  */
8137               if (TREE_TYPE (op0) != result_type)
8138                 op0 = convert (result_type, op0);
8139               converted = 1;
8140             }
8141         }
8142
8143       /* Comparison operations are shortened too but differently.
8144          They identify themselves by setting short_compare = 1.  */
8145
8146       if (short_compare)
8147         {
8148           /* Don't write &op0, etc., because that would prevent op0
8149              from being kept in a register.
8150              Instead, make copies of the our local variables and
8151              pass the copies by reference, then copy them back afterward.  */
8152           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8153           enum tree_code xresultcode = resultcode;
8154           tree val
8155             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8156
8157           if (val != 0)
8158             return val;
8159
8160           op0 = xop0, op1 = xop1;
8161           converted = 1;
8162           resultcode = xresultcode;
8163
8164           if (warn_sign_compare && skip_evaluation == 0)
8165             {
8166               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8167               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8168               int unsignedp0, unsignedp1;
8169               tree primop0 = get_narrower (op0, &unsignedp0);
8170               tree primop1 = get_narrower (op1, &unsignedp1);
8171
8172               xop0 = orig_op0;
8173               xop1 = orig_op1;
8174               STRIP_TYPE_NOPS (xop0);
8175               STRIP_TYPE_NOPS (xop1);
8176
8177               /* Give warnings for comparisons between signed and unsigned
8178                  quantities that may fail.
8179
8180                  Do the checking based on the original operand trees, so that
8181                  casts will be considered, but default promotions won't be.
8182
8183                  Do not warn if the comparison is being done in a signed type,
8184                  since the signed type will only be chosen if it can represent
8185                  all the values of the unsigned type.  */
8186               if (!TYPE_UNSIGNED (result_type))
8187                 /* OK */;
8188               /* Do not warn if both operands are the same signedness.  */
8189               else if (op0_signed == op1_signed)
8190                 /* OK */;
8191               else
8192                 {
8193                   tree sop, uop;
8194
8195                   if (op0_signed)
8196                     sop = xop0, uop = xop1;
8197                   else
8198                     sop = xop1, uop = xop0;
8199
8200                   /* Do not warn if the signed quantity is an
8201                      unsuffixed integer literal (or some static
8202                      constant expression involving such literals or a
8203                      conditional expression involving such literals)
8204                      and it is non-negative.  */
8205                   if (tree_expr_nonnegative_p (sop))
8206                     /* OK */;
8207                   /* Do not warn if the comparison is an equality operation,
8208                      the unsigned quantity is an integral constant, and it
8209                      would fit in the result if the result were signed.  */
8210                   else if (TREE_CODE (uop) == INTEGER_CST
8211                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8212                            && int_fits_type_p
8213                            (uop, c_common_signed_type (result_type)))
8214                     /* OK */;
8215                   /* Do not warn if the unsigned quantity is an enumeration
8216                      constant and its maximum value would fit in the result
8217                      if the result were signed.  */
8218                   else if (TREE_CODE (uop) == INTEGER_CST
8219                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8220                            && int_fits_type_p
8221                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8222                             c_common_signed_type (result_type)))
8223                     /* OK */;
8224                   else
8225                     warning (0, "comparison between signed and unsigned");
8226                 }
8227
8228               /* Warn if two unsigned values are being compared in a size
8229                  larger than their original size, and one (and only one) is the
8230                  result of a `~' operator.  This comparison will always fail.
8231
8232                  Also warn if one operand is a constant, and the constant
8233                  does not have all bits set that are set in the ~ operand
8234                  when it is extended.  */
8235
8236               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8237                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8238                 {
8239                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8240                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8241                                             &unsignedp0);
8242                   else
8243                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8244                                             &unsignedp1);
8245
8246                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8247                     {
8248                       tree primop;
8249                       HOST_WIDE_INT constant, mask;
8250                       int unsignedp, bits;
8251
8252                       if (host_integerp (primop0, 0))
8253                         {
8254                           primop = primop1;
8255                           unsignedp = unsignedp1;
8256                           constant = tree_low_cst (primop0, 0);
8257                         }
8258                       else
8259                         {
8260                           primop = primop0;
8261                           unsignedp = unsignedp0;
8262                           constant = tree_low_cst (primop1, 0);
8263                         }
8264
8265                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8266                       if (bits < TYPE_PRECISION (result_type)
8267                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8268                         {
8269                           mask = (~(HOST_WIDE_INT) 0) << bits;
8270                           if ((mask & constant) != mask)
8271                             warning (0, "comparison of promoted ~unsigned with constant");
8272                         }
8273                     }
8274                   else if (unsignedp0 && unsignedp1
8275                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8276                                < TYPE_PRECISION (result_type))
8277                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8278                                < TYPE_PRECISION (result_type)))
8279                     warning (0, "comparison of promoted ~unsigned with unsigned");
8280                 }
8281             }
8282         }
8283     }
8284
8285   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8286      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8287      Then the expression will be built.
8288      It will be given type FINAL_TYPE if that is nonzero;
8289      otherwise, it will be given type RESULT_TYPE.  */
8290
8291   if (!result_type)
8292     {
8293       binary_op_error (code);
8294       return error_mark_node;
8295     }
8296
8297   if (!converted)
8298     {
8299       if (TREE_TYPE (op0) != result_type)
8300         op0 = convert (result_type, op0);
8301       if (TREE_TYPE (op1) != result_type)
8302         op1 = convert (result_type, op1);
8303
8304       /* This can happen if one operand has a vector type, and the other
8305          has a different type.  */
8306       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8307         return error_mark_node;
8308     }
8309
8310   if (build_type == NULL_TREE)
8311     build_type = result_type;
8312
8313   {
8314     /* Treat expressions in initializers specially as they can't trap.  */
8315     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8316                                                                     build_type,
8317                                                                     op0, op1)
8318                                          : fold_build2 (resultcode, build_type,
8319                                                         op0, op1);
8320
8321     if (final_type != 0)
8322       result = convert (final_type, result);
8323     return result;
8324   }
8325 }
8326
8327
8328 /* Convert EXPR to be a truth-value, validating its type for this
8329    purpose.  */
8330
8331 tree
8332 c_objc_common_truthvalue_conversion (tree expr)
8333 {
8334   switch (TREE_CODE (TREE_TYPE (expr)))
8335     {
8336     case ARRAY_TYPE:
8337       error ("used array that cannot be converted to pointer where scalar is required");
8338       return error_mark_node;
8339
8340     case RECORD_TYPE:
8341       error ("used struct type value where scalar is required");
8342       return error_mark_node;
8343
8344     case UNION_TYPE:
8345       error ("used union type value where scalar is required");
8346       return error_mark_node;
8347
8348     case FUNCTION_TYPE:
8349       gcc_unreachable ();
8350
8351     default:
8352       break;
8353     }
8354
8355   /* ??? Should we also give an error for void and vectors rather than
8356      leaving those to give errors later?  */
8357   return c_common_truthvalue_conversion (expr);
8358 }
8359 \f
8360
8361 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8362    required.  */
8363
8364 tree
8365 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8366                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8367 {
8368   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8369     {
8370       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8371       /* Executing a compound literal inside a function reinitializes
8372          it.  */
8373       if (!TREE_STATIC (decl))
8374         *se = true;
8375       return decl;
8376     }
8377   else
8378     return expr;
8379 }