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, 2006, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  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 "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_assign,
  53   ic_init,
  54   ic_return
  55 };
  56
  57 /* Whether we are building a boolean conversion inside
  58    convert_for_assignment, or some other late binary operation.  If
  59    build_binary_op is called (from code shared with C++) in this case,
  60    then the operands have already been folded and the result will not
  61    be folded again, so C_MAYBE_CONST_EXPR should not be generated.  */
  62 bool in_late_binary_op;
  63
  64 /* The level of nesting inside "__alignof__".  */
  65 int in_alignof;
  66
  67 /* The level of nesting inside "sizeof".  */
  68 int in_sizeof;
  69
  70 /* The level of nesting inside "typeof".  */
  71 int in_typeof;
  72
  73 /* Nonzero if we've already printed a "missing braces around initializer"
  74    message within this initializer.  */
  75 static int missing_braces_mentioned;
  76
  77 static int require_constant_value;
  78 static int require_constant_elements;
  79
  80 static bool null_pointer_constant_p (const_tree);
  81 static tree qualify_type (tree, tree);
  82 static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *);
  83 static int comp_target_types (location_t, tree, tree);
  84 static int function_types_compatible_p (const_tree, const_tree, bool *);
  85 static int type_lists_compatible_p (const_tree, const_tree, bool *);
  86 static tree lookup_field (tree, tree);
  87 static int convert_arguments (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
  88                               tree);
  89 static tree pointer_diff (tree, tree);
  90 static tree convert_for_assignment (location_t, tree, tree, tree,
  91                                     enum impl_conv, bool, tree, tree, int);
  92 static tree valid_compound_expr_initializer (tree, tree);
  93 static void push_string (const char *);
  94 static void push_member_name (tree);
  95 static int spelling_length (void);
  96 static char *print_spelling (char *);
  97 static void warning_init (int, const char *);
  98 static tree digest_init (location_t, tree, tree, tree, bool, bool, int);
  99 static void output_init_element (tree, tree, bool, tree, tree, int, bool);
 100 static void output_pending_init_elements (int);
 101 static int set_designator (int);
 102 static void push_range_stack (tree);
 103 static void add_pending_init (tree, tree, tree, bool);
 104 static void set_nonincremental_init (void);
 105 static void set_nonincremental_init_from_string (tree);
 106 static tree find_init_member (tree);
 107 static void readonly_error (tree, enum lvalue_use);
 108 static void readonly_warning (tree, enum lvalue_use);
 109 static int lvalue_or_else (const_tree, enum lvalue_use);
 110 static void record_maybe_used_decl (tree);
 111 static int comptypes_internal (const_tree, const_tree, bool *);
 112 \f
 113 /* Return true if EXP is a null pointer constant, false otherwise.  */
 114
 115 static bool
 116 null_pointer_constant_p (const_tree expr)
 117 {
 118   /* This should really operate on c_expr structures, but they aren't
 119      yet available everywhere required.  */
 120   tree type = TREE_TYPE (expr);
 121   return (TREE_CODE (expr) == INTEGER_CST
 122           && !TREE_OVERFLOW (expr)
 123           && integer_zerop (expr)
 124           && (INTEGRAL_TYPE_P (type)
 125               || (TREE_CODE (type) == POINTER_TYPE
 126                   && VOID_TYPE_P (TREE_TYPE (type))
 127                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 128 }
 129
 130 /* EXPR may appear in an unevaluated part of an integer constant
 131    expression, but not in an evaluated part.  Wrap it in a
 132    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 133    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 134
 135 static tree
 136 note_integer_operands (tree expr)
 137 {
 138   tree ret;
 139   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 140     {
 141       ret = copy_node (expr);
 142       TREE_OVERFLOW (ret) = 1;
 143     }
 144   else
 145     {
 146       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 147       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 148     }
 149   return ret;
 150 }
 151
 152 /* Having checked whether EXPR may appear in an unevaluated part of an
 153    integer constant expression and found that it may, remove any
 154    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 155    expression.  */
 156
 157 static inline tree
 158 remove_c_maybe_const_expr (tree expr)
 159 {
 160   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 161     return C_MAYBE_CONST_EXPR_EXPR (expr);
 162   else
 163     return expr;
 164 }
 165
 166 \f/* This is a cache to hold if two types are compatible or not.  */
 167
 168 struct tagged_tu_seen_cache {
 169   const struct tagged_tu_seen_cache * next;
 170   const_tree t1;
 171   const_tree t2;
 172   /* The return value of tagged_types_tu_compatible_p if we had seen
 173      these two types already.  */
 174   int val;
 175 };
 176
 177 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 178 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 179
 180 /* Do `exp = require_complete_type (exp);' to make sure exp
 181    does not have an incomplete type.  (That includes void types.)  */
 182
 183 tree
 184 require_complete_type (tree value)
 185 {
 186   tree type = TREE_TYPE (value);
 187
 188   if (value == error_mark_node || type == error_mark_node)
 189     return error_mark_node;
 190
 191   /* First, detect a valid value with a complete type.  */
 192   if (COMPLETE_TYPE_P (type))
 193     return value;
 194
 195   c_incomplete_type_error (value, type);
 196   return error_mark_node;
 197 }
 198
 199 /* Print an error message for invalid use of an incomplete type.
 200    VALUE is the expression that was used (or 0 if that isn't known)
 201    and TYPE is the type that was invalid.  */
 202
 203 void
 204 c_incomplete_type_error (const_tree value, const_tree type)
 205 {
 206   const char *type_code_string;
 207
 208   /* Avoid duplicate error message.  */
 209   if (TREE_CODE (type) == ERROR_MARK)
 210     return;
 211
 212   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 213                      || TREE_CODE (value) == PARM_DECL))
 214     error ("%qD has an incomplete type", value);
 215   else
 216     {
 217     retry:
 218       /* We must print an error message.  Be clever about what it says.  */
 219
 220       switch (TREE_CODE (type))
 221         {
 222         case RECORD_TYPE:
 223           type_code_string = "struct";
 224           break;
 225
 226         case UNION_TYPE:
 227           type_code_string = "union";
 228           break;
 229
 230         case ENUMERAL_TYPE:
 231           type_code_string = "enum";
 232           break;
 233
 234         case VOID_TYPE:
 235           error ("invalid use of void expression");
 236           return;
 237
 238         case ARRAY_TYPE:
 239           if (TYPE_DOMAIN (type))
 240             {
 241               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 242                 {
 243                   error ("invalid use of flexible array member");
 244                   return;
 245                 }
 246               type = TREE_TYPE (type);
 247               goto retry;
 248             }
 249           error ("invalid use of array with unspecified bounds");
 250           return;
 251
 252         default:
 253           gcc_unreachable ();
 254         }
 255
 256       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 257         error ("invalid use of undefined type %<%s %E%>",
 258                type_code_string, TYPE_NAME (type));
 259       else
 260         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 261         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 262     }
 263 }
 264
 265 /* Given a type, apply default promotions wrt unnamed function
 266    arguments and return the new type.  */
 267
 268 tree
 269 c_type_promotes_to (tree type)
 270 {
 271   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 272     return double_type_node;
 273
 274   if (c_promoting_integer_type_p (type))
 275     {
 276       /* Preserve unsignedness if not really getting any wider.  */
 277       if (TYPE_UNSIGNED (type)
 278           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 279         return unsigned_type_node;
 280       return integer_type_node;
 281     }
 282
 283   return type;
 284 }
 285
 286 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 287    as well as those of TYPE.  */
 288
 289 static tree
 290 qualify_type (tree type, tree like)
 291 {
 292   return c_build_qualified_type (type,
 293                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 294 }
 295
 296 /* Return true iff the given tree T is a variable length array.  */
 297
 298 bool
 299 c_vla_type_p (const_tree t)
 300 {
 301   if (TREE_CODE (t) == ARRAY_TYPE
 302       && C_TYPE_VARIABLE_SIZE (t))
 303     return true;
 304   return false;
 305 }
 306 \f
 307 /* Return the composite type of two compatible types.
 308
 309    We assume that comptypes has already been done and returned
 310    nonzero; if that isn't so, this may crash.  In particular, we
 311    assume that qualifiers match.  */
 312
 313 tree
 314 composite_type (tree t1, tree t2)
 315 {
 316   enum tree_code code1;
 317   enum tree_code code2;
 318   tree attributes;
 319
 320   /* Save time if the two types are the same.  */
 321
 322   if (t1 == t2) return t1;
 323
 324   /* If one type is nonsense, use the other.  */
 325   if (t1 == error_mark_node)
 326     return t2;
 327   if (t2 == error_mark_node)
 328     return t1;
 329
 330   code1 = TREE_CODE (t1);
 331   code2 = TREE_CODE (t2);
 332
 333   /* Merge the attributes.  */
 334   attributes = targetm.merge_type_attributes (t1, t2);
 335
 336   /* If one is an enumerated type and the other is the compatible
 337      integer type, the composite type might be either of the two
 338      (DR#013 question 3).  For consistency, use the enumerated type as
 339      the composite type.  */
 340
 341   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 342     return t1;
 343   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 344     return t2;
 345
 346   gcc_assert (code1 == code2);
 347
 348   switch (code1)
 349     {
 350     case POINTER_TYPE:
 351       /* For two pointers, do this recursively on the target type.  */
 352       {
 353         tree pointed_to_1 = TREE_TYPE (t1);
 354         tree pointed_to_2 = TREE_TYPE (t2);
 355         tree target = composite_type (pointed_to_1, pointed_to_2);
 356         t1 = build_pointer_type (target);
 357         t1 = build_type_attribute_variant (t1, attributes);
 358         return qualify_type (t1, t2);
 359       }
 360
 361     case ARRAY_TYPE:
 362       {
 363         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 364         int quals;
 365         tree unqual_elt;
 366         tree d1 = TYPE_DOMAIN (t1);
 367         tree d2 = TYPE_DOMAIN (t2);
 368         bool d1_variable, d2_variable;
 369         bool d1_zero, d2_zero;
 370         bool t1_complete, t2_complete;
 371
 372         /* We should not have any type quals on arrays at all.  */
 373         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 374
 375         t1_complete = COMPLETE_TYPE_P (t1);
 376         t2_complete = COMPLETE_TYPE_P (t2);
 377
 378         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 379         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 380
 381         d1_variable = (!d1_zero
 382                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 383                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 384         d2_variable = (!d2_zero
 385                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 386                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 387         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 388         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 389
 390         /* Save space: see if the result is identical to one of the args.  */
 391         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 392             && (d2_variable || d2_zero || !d1_variable))
 393           return build_type_attribute_variant (t1, attributes);
 394         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 395             && (d1_variable || d1_zero || !d2_variable))
 396           return build_type_attribute_variant (t2, attributes);
 397
 398         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 399           return build_type_attribute_variant (t1, attributes);
 400         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 401           return build_type_attribute_variant (t2, attributes);
 402
 403         /* Merge the element types, and have a size if either arg has
 404            one.  We may have qualifiers on the element types.  To set
 405            up TYPE_MAIN_VARIANT correctly, we need to form the
 406            composite of the unqualified types and add the qualifiers
 407            back at the end.  */
 408         quals = TYPE_QUALS (strip_array_types (elt));
 409         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 410         t1 = build_array_type (unqual_elt,
 411                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 412                                              && (d2_variable
 413                                                  || d2_zero
 414                                                  || !d1_variable))
 415                                             ? t1
 416                                             : t2));
 417         /* Ensure a composite type involving a zero-length array type
 418            is a zero-length type not an incomplete type.  */
 419         if (d1_zero && d2_zero
 420             && (t1_complete || t2_complete)
 421             && !COMPLETE_TYPE_P (t1))
 422           {
 423             TYPE_SIZE (t1) = bitsize_zero_node;
 424             TYPE_SIZE_UNIT (t1) = size_zero_node;
 425           }
 426         t1 = c_build_qualified_type (t1, quals);
 427         return build_type_attribute_variant (t1, attributes);
 428       }
 429
 430     case ENUMERAL_TYPE:
 431     case RECORD_TYPE:
 432     case UNION_TYPE:
 433       if (attributes != NULL)
 434         {
 435           /* Try harder not to create a new aggregate type.  */
 436           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 437             return t1;
 438           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 439             return t2;
 440         }
 441       return build_type_attribute_variant (t1, attributes);
 442
 443     case FUNCTION_TYPE:
 444       /* Function types: prefer the one that specified arg types.
 445          If both do, merge the arg types.  Also merge the return types.  */
 446       {
 447         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 448         tree p1 = TYPE_ARG_TYPES (t1);
 449         tree p2 = TYPE_ARG_TYPES (t2);
 450         int len;
 451         tree newargs, n;
 452         int i;
 453
 454         /* Save space: see if the result is identical to one of the args.  */
 455         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 456           return build_type_attribute_variant (t1, attributes);
 457         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 458           return build_type_attribute_variant (t2, attributes);
 459
 460         /* Simple way if one arg fails to specify argument types.  */
 461         if (TYPE_ARG_TYPES (t1) == 0)
 462          {
 463             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 464             t1 = build_type_attribute_variant (t1, attributes);
 465             return qualify_type (t1, t2);
 466          }
 467         if (TYPE_ARG_TYPES (t2) == 0)
 468          {
 469            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 470            t1 = build_type_attribute_variant (t1, attributes);
 471            return qualify_type (t1, t2);
 472          }
 473
 474         /* If both args specify argument types, we must merge the two
 475            lists, argument by argument.  */
 476         /* Tell global_bindings_p to return false so that variable_size
 477            doesn't die on VLAs in parameter types.  */
 478         c_override_global_bindings_to_false = true;
 479
 480         len = list_length (p1);
 481         newargs = 0;
 482
 483         for (i = 0; i < len; i++)
 484           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 485
 486         n = newargs;
 487
 488         for (; p1;
 489              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 490           {
 491             /* A null type means arg type is not specified.
 492                Take whatever the other function type has.  */
 493             if (TREE_VALUE (p1) == 0)
 494               {
 495                 TREE_VALUE (n) = TREE_VALUE (p2);
 496                 goto parm_done;
 497               }
 498             if (TREE_VALUE (p2) == 0)
 499               {
 500                 TREE_VALUE (n) = TREE_VALUE (p1);
 501                 goto parm_done;
 502               }
 503
 504             /* Given  wait (union {union wait *u; int *i} *)
 505                and  wait (union wait *),
 506                prefer  union wait *  as type of parm.  */
 507             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 508                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 509               {
 510                 tree memb;
 511                 tree mv2 = TREE_VALUE (p2);
 512                 if (mv2 && mv2 != error_mark_node
 513                     && TREE_CODE (mv2) != ARRAY_TYPE)
 514                   mv2 = TYPE_MAIN_VARIANT (mv2);
 515                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 516                      memb; memb = TREE_CHAIN (memb))
 517                   {
 518                     tree mv3 = TREE_TYPE (memb);
 519                     if (mv3 && mv3 != error_mark_node
 520                         && TREE_CODE (mv3) != ARRAY_TYPE)
 521                       mv3 = TYPE_MAIN_VARIANT (mv3);
 522                     if (comptypes (mv3, mv2))
 523                       {
 524                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 525                                                          TREE_VALUE (p2));
 526                         pedwarn (input_location, OPT_pedantic,
 527                                  "function types not truly compatible in ISO C");
 528                         goto parm_done;
 529                       }
 530                   }
 531               }
 532             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 533                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 534               {
 535                 tree memb;
 536                 tree mv1 = TREE_VALUE (p1);
 537                 if (mv1 && mv1 != error_mark_node
 538                     && TREE_CODE (mv1) != ARRAY_TYPE)
 539                   mv1 = TYPE_MAIN_VARIANT (mv1);
 540                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 541                      memb; memb = TREE_CHAIN (memb))
 542                   {
 543                     tree mv3 = TREE_TYPE (memb);
 544                     if (mv3 && mv3 != error_mark_node
 545                         && TREE_CODE (mv3) != ARRAY_TYPE)
 546                       mv3 = TYPE_MAIN_VARIANT (mv3);
 547                     if (comptypes (mv3, mv1))
 548                       {
 549                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 550                                                          TREE_VALUE (p1));
 551                         pedwarn (input_location, OPT_pedantic,
 552                                  "function types not truly compatible in ISO C");
 553                         goto parm_done;
 554                       }
 555                   }
 556               }
 557             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 558           parm_done: ;
 559           }
 560
 561         c_override_global_bindings_to_false = false;
 562         t1 = build_function_type (valtype, newargs);
 563         t1 = qualify_type (t1, t2);
 564         /* ... falls through ...  */
 565       }
 566
 567     default:
 568       return build_type_attribute_variant (t1, attributes);
 569     }
 570
 571 }
 572
 573 /* Return the type of a conditional expression between pointers to
 574    possibly differently qualified versions of compatible types.
 575
 576    We assume that comp_target_types has already been done and returned
 577    nonzero; if that isn't so, this may crash.  */
 578
 579 static tree
 580 common_pointer_type (tree t1, tree t2)
 581 {
 582   tree attributes;
 583   tree pointed_to_1, mv1;
 584   tree pointed_to_2, mv2;
 585   tree target;
 586   unsigned target_quals;
 587
 588   /* Save time if the two types are the same.  */
 589
 590   if (t1 == t2) return t1;
 591
 592   /* If one type is nonsense, use the other.  */
 593   if (t1 == error_mark_node)
 594     return t2;
 595   if (t2 == error_mark_node)
 596     return t1;
 597
 598   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 599               && TREE_CODE (t2) == POINTER_TYPE);
 600
 601   /* Merge the attributes.  */
 602   attributes = targetm.merge_type_attributes (t1, t2);
 603
 604   /* Find the composite type of the target types, and combine the
 605      qualifiers of the two types' targets.  Do not lose qualifiers on
 606      array element types by taking the TYPE_MAIN_VARIANT.  */
 607   mv1 = pointed_to_1 = TREE_TYPE (t1);
 608   mv2 = pointed_to_2 = TREE_TYPE (t2);
 609   if (TREE_CODE (mv1) != ARRAY_TYPE)
 610     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 611   if (TREE_CODE (mv2) != ARRAY_TYPE)
 612     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 613   target = composite_type (mv1, mv2);
 614
 615   /* For function types do not merge const qualifiers, but drop them
 616      if used inconsistently.  The middle-end uses these to mark const
 617      and noreturn functions.  */
 618   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 619     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 620   else
 621     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 622   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 623   return build_type_attribute_variant (t1, attributes);
 624 }
 625
 626 /* Return the common type for two arithmetic types under the usual
 627    arithmetic conversions.  The default conversions have already been
 628    applied, and enumerated types converted to their compatible integer
 629    types.  The resulting type is unqualified and has no attributes.
 630
 631    This is the type for the result of most arithmetic operations
 632    if the operands have the given two types.  */
 633
 634 static tree
 635 c_common_type (tree t1, tree t2)
 636 {
 637   enum tree_code code1;
 638   enum tree_code code2;
 639
 640   /* If one type is nonsense, use the other.  */
 641   if (t1 == error_mark_node)
 642     return t2;
 643   if (t2 == error_mark_node)
 644     return t1;
 645
 646   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 647     t1 = TYPE_MAIN_VARIANT (t1);
 648
 649   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 650     t2 = TYPE_MAIN_VARIANT (t2);
 651
 652   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 653     t1 = build_type_attribute_variant (t1, NULL_TREE);
 654
 655   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 656     t2 = build_type_attribute_variant (t2, NULL_TREE);
 657
 658   /* Save time if the two types are the same.  */
 659
 660   if (t1 == t2) return t1;
 661
 662   code1 = TREE_CODE (t1);
 663   code2 = TREE_CODE (t2);
 664
 665   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 666               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 667               || code1 == INTEGER_TYPE);
 668   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 669               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 670               || code2 == INTEGER_TYPE);
 671
 672   /* When one operand is a decimal float type, the other operand cannot be
 673      a generic float type or a complex type.  We also disallow vector types
 674      here.  */
 675   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 676       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 677     {
 678       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 679         {
 680           error ("can%'t mix operands of decimal float and vector types");
 681           return error_mark_node;
 682         }
 683       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 684         {
 685           error ("can%'t mix operands of decimal float and complex types");
 686           return error_mark_node;
 687         }
 688       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 689         {
 690           error ("can%'t mix operands of decimal float and other float types");
 691           return error_mark_node;
 692         }
 693     }
 694
 695   /* If one type is a vector type, return that type.  (How the usual
 696      arithmetic conversions apply to the vector types extension is not
 697      precisely specified.)  */
 698   if (code1 == VECTOR_TYPE)
 699     return t1;
 700
 701   if (code2 == VECTOR_TYPE)
 702     return t2;
 703
 704   /* If one type is complex, form the common type of the non-complex
 705      components, then make that complex.  Use T1 or T2 if it is the
 706      required type.  */
 707   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 708     {
 709       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 710       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 711       tree subtype = c_common_type (subtype1, subtype2);
 712
 713       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 714         return t1;
 715       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 716         return t2;
 717       else
 718         return build_complex_type (subtype);
 719     }
 720
 721   /* If only one is real, use it as the result.  */
 722
 723   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 724     return t1;
 725
 726   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 727     return t2;
 728
 729   /* If both are real and either are decimal floating point types, use
 730      the decimal floating point type with the greater precision. */
 731
 732   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 733     {
 734       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 735           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 736         return dfloat128_type_node;
 737       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 738                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 739         return dfloat64_type_node;
 740       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 741                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 742         return dfloat32_type_node;
 743     }
 744
 745   /* Deal with fixed-point types.  */
 746   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 747     {
 748       unsigned int unsignedp = 0, satp = 0;
 749       enum machine_mode m1, m2;
 750       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 751
 752       m1 = TYPE_MODE (t1);
 753       m2 = TYPE_MODE (t2);
 754
 755       /* If one input type is saturating, the result type is saturating.  */
 756       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 757         satp = 1;
 758
 759       /* If both fixed-point types are unsigned, the result type is unsigned.
 760          When mixing fixed-point and integer types, follow the sign of the
 761          fixed-point type.
 762          Otherwise, the result type is signed.  */
 763       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 764            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 765           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 766               && TYPE_UNSIGNED (t1))
 767           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 768               && TYPE_UNSIGNED (t2)))
 769         unsignedp = 1;
 770
 771       /* The result type is signed.  */
 772       if (unsignedp == 0)
 773         {
 774           /* If the input type is unsigned, we need to convert to the
 775              signed type.  */
 776           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 777             {
 778               enum mode_class mclass = (enum mode_class) 0;
 779               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 780                 mclass = MODE_FRACT;
 781               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 782                 mclass = MODE_ACCUM;
 783               else
 784                 gcc_unreachable ();
 785               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 786             }
 787           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 788             {
 789               enum mode_class mclass = (enum mode_class) 0;
 790               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 791                 mclass = MODE_FRACT;
 792               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 793                 mclass = MODE_ACCUM;
 794               else
 795                 gcc_unreachable ();
 796               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 797             }
 798         }
 799
 800       if (code1 == FIXED_POINT_TYPE)
 801         {
 802           fbit1 = GET_MODE_FBIT (m1);
 803           ibit1 = GET_MODE_IBIT (m1);
 804         }
 805       else
 806         {
 807           fbit1 = 0;
 808           /* Signed integers need to subtract one sign bit.  */
 809           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 810         }
 811
 812       if (code2 == FIXED_POINT_TYPE)
 813         {
 814           fbit2 = GET_MODE_FBIT (m2);
 815           ibit2 = GET_MODE_IBIT (m2);
 816         }
 817       else
 818         {
 819           fbit2 = 0;
 820           /* Signed integers need to subtract one sign bit.  */
 821           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 822         }
 823
 824       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 825       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 826       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 827                                                  satp);
 828     }
 829
 830   /* Both real or both integers; use the one with greater precision.  */
 831
 832   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 833     return t1;
 834   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 835     return t2;
 836
 837   /* Same precision.  Prefer long longs to longs to ints when the
 838      same precision, following the C99 rules on integer type rank
 839      (which are equivalent to the C90 rules for C90 types).  */
 840
 841   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 842       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 843     return long_long_unsigned_type_node;
 844
 845   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 846       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 847     {
 848       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 849         return long_long_unsigned_type_node;
 850       else
 851         return long_long_integer_type_node;
 852     }
 853
 854   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 855       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 856     return long_unsigned_type_node;
 857
 858   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 859       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 860     {
 861       /* But preserve unsignedness from the other type,
 862          since long cannot hold all the values of an unsigned int.  */
 863       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 864         return long_unsigned_type_node;
 865       else
 866         return long_integer_type_node;
 867     }
 868
 869   /* Likewise, prefer long double to double even if same size.  */
 870   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 871       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 872     return long_double_type_node;
 873
 874   /* Otherwise prefer the unsigned one.  */
 875
 876   if (TYPE_UNSIGNED (t1))
 877     return t1;
 878   else
 879     return t2;
 880 }
 881 \f
 882 /* Wrapper around c_common_type that is used by c-common.c and other
 883    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 884    are allowed here and are converted to their compatible integer types.
 885    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 886    preferably a non-Boolean type as the common type.  */
 887 tree
 888 common_type (tree t1, tree t2)
 889 {
 890   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 891     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 892   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 893     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 894
 895   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 896   if (TREE_CODE (t1) == BOOLEAN_TYPE
 897       && TREE_CODE (t2) == BOOLEAN_TYPE)
 898     return boolean_type_node;
 899
 900   /* If either type is BOOLEAN_TYPE, then return the other.  */
 901   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 902     return t2;
 903   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 904     return t1;
 905
 906   return c_common_type (t1, t2);
 907 }
 908
 909 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 910    or various other operations.  Return 2 if they are compatible
 911    but a warning may be needed if you use them together.  */
 912
 913 int
 914 comptypes (tree type1, tree type2)
 915 {
 916   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 917   int val;
 918
 919   val = comptypes_internal (type1, type2, NULL);
 920   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 921
 922   return val;
 923 }
 924
 925 /* Like comptypes, but if it returns non-zero because enum and int are
 926    compatible, it sets *ENUM_AND_INT_P to true.  */
 927
 928 static int
 929 comptypes_check_enum_int (tree type1, tree type2, bool *enum_and_int_p)
 930 {
 931   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 932   int val;
 933
 934   val = comptypes_internal (type1, type2, enum_and_int_p);
 935   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 936
 937   return val;
 938 }
 939 \f
 940 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 941    or various other operations.  Return 2 if they are compatible
 942    but a warning may be needed if you use them together.  If
 943    ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
 944    compatible integer type, then this sets *ENUM_AND_INT_P to true;
 945    *ENUM_AND_INT_P is never set to false.  This differs from
 946    comptypes, in that we don't free the seen types.  */
 947
 948 static int
 949 comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p)
 950 {
 951   const_tree t1 = type1;
 952   const_tree t2 = type2;
 953   int attrval, val;
 954
 955   /* Suppress errors caused by previously reported errors.  */
 956
 957   if (t1 == t2 || !t1 || !t2
 958       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 959     return 1;
 960
 961   /* If either type is the internal version of sizetype, return the
 962      language version.  */
 963   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 964       && TYPE_ORIG_SIZE_TYPE (t1))
 965     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 966
 967   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 968       && TYPE_ORIG_SIZE_TYPE (t2))
 969     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 970
 971
 972   /* Enumerated types are compatible with integer types, but this is
 973      not transitive: two enumerated types in the same translation unit
 974      are compatible with each other only if they are the same type.  */
 975
 976   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 977     {
 978       t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 979       if (enum_and_int_p != NULL && TREE_CODE (t2) != VOID_TYPE)
 980         *enum_and_int_p = true;
 981     }
 982   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 983     {
 984       t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 985       if (enum_and_int_p != NULL && TREE_CODE (t1) != VOID_TYPE)
 986         *enum_and_int_p = true;
 987     }
 988
 989   if (t1 == t2)
 990     return 1;
 991
 992   /* Different classes of types can't be compatible.  */
 993
 994   if (TREE_CODE (t1) != TREE_CODE (t2))
 995     return 0;
 996
 997   /* Qualifiers must match. C99 6.7.3p9 */
 998
 999   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
1000     return 0;
1001
1002   /* Allow for two different type nodes which have essentially the same
1003      definition.  Note that we already checked for equality of the type
1004      qualifiers (just above).  */
1005
1006   if (TREE_CODE (t1) != ARRAY_TYPE
1007       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
1008     return 1;
1009
1010   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1011   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
1012      return 0;
1013
1014   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1015   val = 0;
1016
1017   switch (TREE_CODE (t1))
1018     {
1019     case POINTER_TYPE:
1020       /* Do not remove mode or aliasing information.  */
1021       if (TYPE_MODE (t1) != TYPE_MODE (t2)
1022           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
1023         break;
1024       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1025              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1026                                        enum_and_int_p));
1027       break;
1028
1029     case FUNCTION_TYPE:
1030       val = function_types_compatible_p (t1, t2, enum_and_int_p);
1031       break;
1032
1033     case ARRAY_TYPE:
1034       {
1035         tree d1 = TYPE_DOMAIN (t1);
1036         tree d2 = TYPE_DOMAIN (t2);
1037         bool d1_variable, d2_variable;
1038         bool d1_zero, d2_zero;
1039         val = 1;
1040
1041         /* Target types must match incl. qualifiers.  */
1042         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1043             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1044                                                enum_and_int_p)))
1045           return 0;
1046
1047         /* Sizes must match unless one is missing or variable.  */
1048         if (d1 == 0 || d2 == 0 || d1 == d2)
1049           break;
1050
1051         d1_zero = !TYPE_MAX_VALUE (d1);
1052         d2_zero = !TYPE_MAX_VALUE (d2);
1053
1054         d1_variable = (!d1_zero
1055                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1056                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1057         d2_variable = (!d2_zero
1058                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1059                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1060         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1061         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1062
1063         if (d1_variable || d2_variable)
1064           break;
1065         if (d1_zero && d2_zero)
1066           break;
1067         if (d1_zero || d2_zero
1068             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1069             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1070           val = 0;
1071
1072         break;
1073       }
1074
1075     case ENUMERAL_TYPE:
1076     case RECORD_TYPE:
1077     case UNION_TYPE:
1078       if (val != 1 && !same_translation_unit_p (t1, t2))
1079         {
1080           tree a1 = TYPE_ATTRIBUTES (t1);
1081           tree a2 = TYPE_ATTRIBUTES (t2);
1082
1083           if (! attribute_list_contained (a1, a2)
1084               && ! attribute_list_contained (a2, a1))
1085             break;
1086
1087           if (attrval != 2)
1088             return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1089           val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1090         }
1091       break;
1092
1093     case VECTOR_TYPE:
1094       val = (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1095              && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1096                                     enum_and_int_p));
1097       break;
1098
1099     default:
1100       break;
1101     }
1102   return attrval == 2 && val == 1 ? 2 : val;
1103 }
1104
1105 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1106    ignoring their qualifiers.  */
1107
1108 static int
1109 comp_target_types (location_t location, tree ttl, tree ttr)
1110 {
1111   int val;
1112   tree mvl, mvr;
1113   bool enum_and_int_p;
1114
1115   /* Do not lose qualifiers on element types of array types that are
1116      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1117   mvl = TREE_TYPE (ttl);
1118   mvr = TREE_TYPE (ttr);
1119   if (TREE_CODE (mvl) != ARRAY_TYPE)
1120     mvl = TYPE_MAIN_VARIANT (mvl);
1121   if (TREE_CODE (mvr) != ARRAY_TYPE)
1122     mvr = TYPE_MAIN_VARIANT (mvr);
1123   enum_and_int_p = false;
1124   val = comptypes_check_enum_int (mvl, mvr, &enum_and_int_p);
1125
1126   if (val == 2)
1127     pedwarn (location, OPT_pedantic, "types are not quite compatible");
1128
1129   if (val == 1 && enum_and_int_p && warn_cxx_compat)
1130     warning_at (location, OPT_Wc___compat,
1131                 "pointer target types incompatible in C++");
1132
1133   return val;
1134 }
1135 \f
1136 /* Subroutines of `comptypes'.  */
1137
1138 /* Determine whether two trees derive from the same translation unit.
1139    If the CONTEXT chain ends in a null, that tree's context is still
1140    being parsed, so if two trees have context chains ending in null,
1141    they're in the same translation unit.  */
1142 int
1143 same_translation_unit_p (const_tree t1, const_tree t2)
1144 {
1145   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1146     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1147       {
1148       case tcc_declaration:
1149         t1 = DECL_CONTEXT (t1); break;
1150       case tcc_type:
1151         t1 = TYPE_CONTEXT (t1); break;
1152       case tcc_exceptional:
1153         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1154       default: gcc_unreachable ();
1155       }
1156
1157   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1158     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1159       {
1160       case tcc_declaration:
1161         t2 = DECL_CONTEXT (t2); break;
1162       case tcc_type:
1163         t2 = TYPE_CONTEXT (t2); break;
1164       case tcc_exceptional:
1165         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1166       default: gcc_unreachable ();
1167       }
1168
1169   return t1 == t2;
1170 }
1171
1172 /* Allocate the seen two types, assuming that they are compatible. */
1173
1174 static struct tagged_tu_seen_cache *
1175 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1176 {
1177   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1178   tu->next = tagged_tu_seen_base;
1179   tu->t1 = t1;
1180   tu->t2 = t2;
1181
1182   tagged_tu_seen_base = tu;
1183
1184   /* The C standard says that two structures in different translation
1185      units are compatible with each other only if the types of their
1186      fields are compatible (among other things).  We assume that they
1187      are compatible until proven otherwise when building the cache.
1188      An example where this can occur is:
1189      struct a
1190      {
1191        struct a *next;
1192      };
1193      If we are comparing this against a similar struct in another TU,
1194      and did not assume they were compatible, we end up with an infinite
1195      loop.  */
1196   tu->val = 1;
1197   return tu;
1198 }
1199
1200 /* Free the seen types until we get to TU_TIL. */
1201
1202 static void
1203 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1204 {
1205   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1206   while (tu != tu_til)
1207     {
1208       const struct tagged_tu_seen_cache *const tu1
1209         = (const struct tagged_tu_seen_cache *) tu;
1210       tu = tu1->next;
1211       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1212     }
1213   tagged_tu_seen_base = tu_til;
1214 }
1215
1216 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1217    compatible.  If the two types are not the same (which has been
1218    checked earlier), this can only happen when multiple translation
1219    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1220    rules.  ENUM_AND_INT_P is as in comptypes_internal.  */
1221
1222 static int
1223 tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
1224                               bool *enum_and_int_p)
1225 {
1226   tree s1, s2;
1227   bool needs_warning = false;
1228
1229   /* We have to verify that the tags of the types are the same.  This
1230      is harder than it looks because this may be a typedef, so we have
1231      to go look at the original type.  It may even be a typedef of a
1232      typedef...
1233      In the case of compiler-created builtin structs the TYPE_DECL
1234      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1235   while (TYPE_NAME (t1)
1236          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1237          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1238     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1239
1240   while (TYPE_NAME (t2)
1241          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1242          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1243     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1244
1245   /* C90 didn't have the requirement that the two tags be the same.  */
1246   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1247     return 0;
1248
1249   /* C90 didn't say what happened if one or both of the types were
1250      incomplete; we choose to follow C99 rules here, which is that they
1251      are compatible.  */
1252   if (TYPE_SIZE (t1) == NULL
1253       || TYPE_SIZE (t2) == NULL)
1254     return 1;
1255
1256   {
1257     const struct tagged_tu_seen_cache * tts_i;
1258     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1259       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1260         return tts_i->val;
1261   }
1262
1263   switch (TREE_CODE (t1))
1264     {
1265     case ENUMERAL_TYPE:
1266       {
1267         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1268         /* Speed up the case where the type values are in the same order.  */
1269         tree tv1 = TYPE_VALUES (t1);
1270         tree tv2 = TYPE_VALUES (t2);
1271
1272         if (tv1 == tv2)
1273           {
1274             return 1;
1275           }
1276
1277         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1278           {
1279             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1280               break;
1281             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1282               {
1283                 tu->val = 0;
1284                 return 0;
1285               }
1286           }
1287
1288         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1289           {
1290             return 1;
1291           }
1292         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1293           {
1294             tu->val = 0;
1295             return 0;
1296           }
1297
1298         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1299           {
1300             tu->val = 0;
1301             return 0;
1302           }
1303
1304         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1305           {
1306             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1307             if (s2 == NULL
1308                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1309               {
1310                 tu->val = 0;
1311                 return 0;
1312               }
1313           }
1314         return 1;
1315       }
1316
1317     case UNION_TYPE:
1318       {
1319         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1320         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1321           {
1322             tu->val = 0;
1323             return 0;
1324           }
1325
1326         /*  Speed up the common case where the fields are in the same order. */
1327         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1328              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1329           {
1330             int result;
1331
1332             if (DECL_NAME (s1) != DECL_NAME (s2))
1333               break;
1334             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1335                                          enum_and_int_p);
1336
1337             if (result != 1 && !DECL_NAME (s1))
1338               break;
1339             if (result == 0)
1340               {
1341                 tu->val = 0;
1342                 return 0;
1343               }
1344             if (result == 2)
1345               needs_warning = true;
1346
1347             if (TREE_CODE (s1) == FIELD_DECL
1348                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1349                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1350               {
1351                 tu->val = 0;
1352                 return 0;
1353               }
1354           }
1355         if (!s1 && !s2)
1356           {
1357             tu->val = needs_warning ? 2 : 1;
1358             return tu->val;
1359           }
1360
1361         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1362           {
1363             bool ok = false;
1364
1365             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1366               if (DECL_NAME (s1) == DECL_NAME (s2))
1367                 {
1368                   int result;
1369
1370                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1371                                                enum_and_int_p);
1372
1373                   if (result != 1 && !DECL_NAME (s1))
1374                     continue;
1375                   if (result == 0)
1376                     {
1377                       tu->val = 0;
1378                       return 0;
1379                     }
1380                   if (result == 2)
1381                     needs_warning = true;
1382
1383                   if (TREE_CODE (s1) == FIELD_DECL
1384                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1385                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1386                     break;
1387
1388                   ok = true;
1389                   break;
1390                 }
1391             if (!ok)
1392               {
1393                 tu->val = 0;
1394                 return 0;
1395               }
1396           }
1397         tu->val = needs_warning ? 2 : 10;
1398         return tu->val;
1399       }
1400
1401     case RECORD_TYPE:
1402       {
1403         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1404
1405         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1406              s1 && s2;
1407              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1408           {
1409             int result;
1410             if (TREE_CODE (s1) != TREE_CODE (s2)
1411                 || DECL_NAME (s1) != DECL_NAME (s2))
1412               break;
1413             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1414                                          enum_and_int_p);
1415             if (result == 0)
1416               break;
1417             if (result == 2)
1418               needs_warning = true;
1419
1420             if (TREE_CODE (s1) == FIELD_DECL
1421                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1422                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1423               break;
1424           }
1425         if (s1 && s2)
1426           tu->val = 0;
1427         else
1428           tu->val = needs_warning ? 2 : 1;
1429         return tu->val;
1430       }
1431
1432     default:
1433       gcc_unreachable ();
1434     }
1435 }
1436
1437 /* Return 1 if two function types F1 and F2 are compatible.
1438    If either type specifies no argument types,
1439    the other must specify a fixed number of self-promoting arg types.
1440    Otherwise, if one type specifies only the number of arguments,
1441    the other must specify that number of self-promoting arg types.
1442    Otherwise, the argument types must match.
1443    ENUM_AND_INT_P is as in comptypes_internal.  */
1444
1445 static int
1446 function_types_compatible_p (const_tree f1, const_tree f2,
1447                              bool *enum_and_int_p)
1448 {
1449   tree args1, args2;
1450   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1451   int val = 1;
1452   int val1;
1453   tree ret1, ret2;
1454
1455   ret1 = TREE_TYPE (f1);
1456   ret2 = TREE_TYPE (f2);
1457
1458   /* 'volatile' qualifiers on a function's return type used to mean
1459      the function is noreturn.  */
1460   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1461     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1462   if (TYPE_VOLATILE (ret1))
1463     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1464                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1465   if (TYPE_VOLATILE (ret2))
1466     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1467                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1468   val = comptypes_internal (ret1, ret2, enum_and_int_p);
1469   if (val == 0)
1470     return 0;
1471
1472   args1 = TYPE_ARG_TYPES (f1);
1473   args2 = TYPE_ARG_TYPES (f2);
1474
1475   /* An unspecified parmlist matches any specified parmlist
1476      whose argument types don't need default promotions.  */
1477
1478   if (args1 == 0)
1479     {
1480       if (!self_promoting_args_p (args2))
1481         return 0;
1482       /* If one of these types comes from a non-prototype fn definition,
1483          compare that with the other type's arglist.
1484          If they don't match, ask for a warning (but no error).  */
1485       if (TYPE_ACTUAL_ARG_TYPES (f1)
1486           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
1487                                            enum_and_int_p))
1488         val = 2;
1489       return val;
1490     }
1491   if (args2 == 0)
1492     {
1493       if (!self_promoting_args_p (args1))
1494         return 0;
1495       if (TYPE_ACTUAL_ARG_TYPES (f2)
1496           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
1497                                            enum_and_int_p))
1498         val = 2;
1499       return val;
1500     }
1501
1502   /* Both types have argument lists: compare them and propagate results.  */
1503   val1 = type_lists_compatible_p (args1, args2, enum_and_int_p);
1504   return val1 != 1 ? val1 : val;
1505 }
1506
1507 /* Check two lists of types for compatibility, returning 0 for
1508    incompatible, 1 for compatible, or 2 for compatible with
1509    warning.  ENUM_AND_INT_P is as in comptypes_internal.  */
1510
1511 static int
1512 type_lists_compatible_p (const_tree args1, const_tree args2,
1513                          bool *enum_and_int_p)
1514 {
1515   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1516   int val = 1;
1517   int newval = 0;
1518
1519   while (1)
1520     {
1521       tree a1, mv1, a2, mv2;
1522       if (args1 == 0 && args2 == 0)
1523         return val;
1524       /* If one list is shorter than the other,
1525          they fail to match.  */
1526       if (args1 == 0 || args2 == 0)
1527         return 0;
1528       mv1 = a1 = TREE_VALUE (args1);
1529       mv2 = a2 = TREE_VALUE (args2);
1530       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1531         mv1 = TYPE_MAIN_VARIANT (mv1);
1532       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1533         mv2 = TYPE_MAIN_VARIANT (mv2);
1534       /* A null pointer instead of a type
1535          means there is supposed to be an argument
1536          but nothing is specified about what type it has.
1537          So match anything that self-promotes.  */
1538       if (a1 == 0)
1539         {
1540           if (c_type_promotes_to (a2) != a2)
1541             return 0;
1542         }
1543       else if (a2 == 0)
1544         {
1545           if (c_type_promotes_to (a1) != a1)
1546             return 0;
1547         }
1548       /* If one of the lists has an error marker, ignore this arg.  */
1549       else if (TREE_CODE (a1) == ERROR_MARK
1550                || TREE_CODE (a2) == ERROR_MARK)
1551         ;
1552       else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p)))
1553         {
1554           /* Allow  wait (union {union wait *u; int *i} *)
1555              and  wait (union wait *)  to be compatible.  */
1556           if (TREE_CODE (a1) == UNION_TYPE
1557               && (TYPE_NAME (a1) == 0
1558                   || TYPE_TRANSPARENT_UNION (a1))
1559               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1560               && tree_int_cst_equal (TYPE_SIZE (a1),
1561                                      TYPE_SIZE (a2)))
1562             {
1563               tree memb;
1564               for (memb = TYPE_FIELDS (a1);
1565                    memb; memb = TREE_CHAIN (memb))
1566                 {
1567                   tree mv3 = TREE_TYPE (memb);
1568                   if (mv3 && mv3 != error_mark_node
1569                       && TREE_CODE (mv3) != ARRAY_TYPE)
1570                     mv3 = TYPE_MAIN_VARIANT (mv3);
1571                   if (comptypes_internal (mv3, mv2, enum_and_int_p))
1572                     break;
1573                 }
1574               if (memb == 0)
1575                 return 0;
1576             }
1577           else if (TREE_CODE (a2) == UNION_TYPE
1578                    && (TYPE_NAME (a2) == 0
1579                        || TYPE_TRANSPARENT_UNION (a2))
1580                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1581                    && tree_int_cst_equal (TYPE_SIZE (a2),
1582                                           TYPE_SIZE (a1)))
1583             {
1584               tree memb;
1585               for (memb = TYPE_FIELDS (a2);
1586                    memb; memb = TREE_CHAIN (memb))
1587                 {
1588                   tree mv3 = TREE_TYPE (memb);
1589                   if (mv3 && mv3 != error_mark_node
1590                       && TREE_CODE (mv3) != ARRAY_TYPE)
1591                     mv3 = TYPE_MAIN_VARIANT (mv3);
1592                   if (comptypes_internal (mv3, mv1, enum_and_int_p))
1593                     break;
1594                 }
1595               if (memb == 0)
1596                 return 0;
1597             }
1598           else
1599             return 0;
1600         }
1601
1602       /* comptypes said ok, but record if it said to warn.  */
1603       if (newval > val)
1604         val = newval;
1605
1606       args1 = TREE_CHAIN (args1);
1607       args2 = TREE_CHAIN (args2);
1608     }
1609 }
1610 \f
1611 /* Compute the size to increment a pointer by.  */
1612
1613 static tree
1614 c_size_in_bytes (const_tree type)
1615 {
1616   enum tree_code code = TREE_CODE (type);
1617
1618   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1619     return size_one_node;
1620
1621   if (!COMPLETE_OR_VOID_TYPE_P (type))
1622     {
1623       error ("arithmetic on pointer to an incomplete type");
1624       return size_one_node;
1625     }
1626
1627   /* Convert in case a char is more than one unit.  */
1628   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1629                      size_int (TYPE_PRECISION (char_type_node)
1630                                / BITS_PER_UNIT));
1631 }
1632 \f
1633 /* Return either DECL or its known constant value (if it has one).  */
1634
1635 tree
1636 decl_constant_value (tree decl)
1637 {
1638   if (/* Don't change a variable array bound or initial value to a constant
1639          in a place where a variable is invalid.  Note that DECL_INITIAL
1640          isn't valid for a PARM_DECL.  */
1641       current_function_decl != 0
1642       && TREE_CODE (decl) != PARM_DECL
1643       && !TREE_THIS_VOLATILE (decl)
1644       && TREE_READONLY (decl)
1645       && DECL_INITIAL (decl) != 0
1646       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1647       /* This is invalid if initial value is not constant.
1648          If it has either a function call, a memory reference,
1649          or a variable, then re-evaluating it could give different results.  */
1650       && TREE_CONSTANT (DECL_INITIAL (decl))
1651       /* Check for cases where this is sub-optimal, even though valid.  */
1652       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1653     return DECL_INITIAL (decl);
1654   return decl;
1655 }
1656
1657 /* Convert the array expression EXP to a pointer.  */
1658 static tree
1659 array_to_pointer_conversion (location_t loc, tree exp)
1660 {
1661   tree orig_exp = exp;
1662   tree type = TREE_TYPE (exp);
1663   tree adr;
1664   tree restype = TREE_TYPE (type);
1665   tree ptrtype;
1666
1667   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1668
1669   STRIP_TYPE_NOPS (exp);
1670
1671   if (TREE_NO_WARNING (orig_exp))
1672     TREE_NO_WARNING (exp) = 1;
1673
1674   ptrtype = build_pointer_type (restype);
1675
1676   if (TREE_CODE (exp) == INDIRECT_REF)
1677     return convert (ptrtype, TREE_OPERAND (exp, 0));
1678
1679   adr = build_unary_op (loc, ADDR_EXPR, exp, 1);
1680   return convert (ptrtype, adr);
1681 }
1682
1683 /* Convert the function expression EXP to a pointer.  */
1684 static tree
1685 function_to_pointer_conversion (location_t loc, tree exp)
1686 {
1687   tree orig_exp = exp;
1688
1689   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1690
1691   STRIP_TYPE_NOPS (exp);
1692
1693   if (TREE_NO_WARNING (orig_exp))
1694     TREE_NO_WARNING (exp) = 1;
1695
1696   return build_unary_op (loc, ADDR_EXPR, exp, 0);
1697 }
1698
1699 /* Perform the default conversion of arrays and functions to pointers.
1700    Return the result of converting EXP.  For any other expression, just
1701    return EXP.
1702
1703    LOC is the location of the expression.  */
1704
1705 struct c_expr
1706 default_function_array_conversion (location_t loc, struct c_expr exp)
1707 {
1708   tree orig_exp = exp.value;
1709   tree type = TREE_TYPE (exp.value);
1710   enum tree_code code = TREE_CODE (type);
1711
1712   switch (code)
1713     {
1714     case ARRAY_TYPE:
1715       {
1716         bool not_lvalue = false;
1717         bool lvalue_array_p;
1718
1719         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1720                 || CONVERT_EXPR_P (exp.value))
1721                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1722           {
1723             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1724               not_lvalue = true;
1725             exp.value = TREE_OPERAND (exp.value, 0);
1726           }
1727
1728         if (TREE_NO_WARNING (orig_exp))
1729           TREE_NO_WARNING (exp.value) = 1;
1730
1731         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1732         if (!flag_isoc99 && !lvalue_array_p)
1733           {
1734             /* Before C99, non-lvalue arrays do not decay to pointers.
1735                Normally, using such an array would be invalid; but it can
1736                be used correctly inside sizeof or as a statement expression.
1737                Thus, do not give an error here; an error will result later.  */
1738             return exp;
1739           }
1740
1741         exp.value = array_to_pointer_conversion (loc, exp.value);
1742       }
1743       break;
1744     case FUNCTION_TYPE:
1745       exp.value = function_to_pointer_conversion (loc, exp.value);
1746       break;
1747     default:
1748       break;
1749     }
1750
1751   return exp;
1752 }
1753
1754
1755 /* EXP is an expression of integer type.  Apply the integer promotions
1756    to it and return the promoted value.  */
1757
1758 tree
1759 perform_integral_promotions (tree exp)
1760 {
1761   tree type = TREE_TYPE (exp);
1762   enum tree_code code = TREE_CODE (type);
1763
1764   gcc_assert (INTEGRAL_TYPE_P (type));
1765
1766   /* Normally convert enums to int,
1767      but convert wide enums to something wider.  */
1768   if (code == ENUMERAL_TYPE)
1769     {
1770       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1771                                           TYPE_PRECISION (integer_type_node)),
1772                                      ((TYPE_PRECISION (type)
1773                                        >= TYPE_PRECISION (integer_type_node))
1774                                       && TYPE_UNSIGNED (type)));
1775
1776       return convert (type, exp);
1777     }
1778
1779   /* ??? This should no longer be needed now bit-fields have their
1780      proper types.  */
1781   if (TREE_CODE (exp) == COMPONENT_REF
1782       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1783       /* If it's thinner than an int, promote it like a
1784          c_promoting_integer_type_p, otherwise leave it alone.  */
1785       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1786                                TYPE_PRECISION (integer_type_node)))
1787     return convert (integer_type_node, exp);
1788
1789   if (c_promoting_integer_type_p (type))
1790     {
1791       /* Preserve unsignedness if not really getting any wider.  */
1792       if (TYPE_UNSIGNED (type)
1793           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1794         return convert (unsigned_type_node, exp);
1795
1796       return convert (integer_type_node, exp);
1797     }
1798
1799   return exp;
1800 }
1801
1802
1803 /* Perform default promotions for C data used in expressions.
1804    Enumeral types or short or char are converted to int.
1805    In addition, manifest constants symbols are replaced by their values.  */
1806
1807 tree
1808 default_conversion (tree exp)
1809 {
1810   tree orig_exp;
1811   tree type = TREE_TYPE (exp);
1812   enum tree_code code = TREE_CODE (type);
1813   tree promoted_type;
1814
1815   /* Functions and arrays have been converted during parsing.  */
1816   gcc_assert (code != FUNCTION_TYPE);
1817   if (code == ARRAY_TYPE)
1818     return exp;
1819
1820   /* Constants can be used directly unless they're not loadable.  */
1821   if (TREE_CODE (exp) == CONST_DECL)
1822     exp = DECL_INITIAL (exp);
1823
1824   /* Strip no-op conversions.  */
1825   orig_exp = exp;
1826   STRIP_TYPE_NOPS (exp);
1827
1828   if (TREE_NO_WARNING (orig_exp))
1829     TREE_NO_WARNING (exp) = 1;
1830
1831   if (code == VOID_TYPE)
1832     {
1833       error ("void value not ignored as it ought to be");
1834       return error_mark_node;
1835     }
1836
1837   exp = require_complete_type (exp);
1838   if (exp == error_mark_node)
1839     return error_mark_node;
1840
1841   promoted_type = targetm.promoted_type (type);
1842   if (promoted_type)
1843     return convert (promoted_type, exp);
1844
1845   if (INTEGRAL_TYPE_P (type))
1846     return perform_integral_promotions (exp);
1847
1848   return exp;
1849 }
1850 \f
1851 /* Look up COMPONENT in a structure or union DECL.
1852
1853    If the component name is not found, returns NULL_TREE.  Otherwise,
1854    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1855    stepping down the chain to the component, which is in the last
1856    TREE_VALUE of the list.  Normally the list is of length one, but if
1857    the component is embedded within (nested) anonymous structures or
1858    unions, the list steps down the chain to the component.  */
1859
1860 static tree
1861 lookup_field (tree decl, tree component)
1862 {
1863   tree type = TREE_TYPE (decl);
1864   tree field;
1865
1866   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1867      to the field elements.  Use a binary search on this array to quickly
1868      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1869      will always be set for structures which have many elements.  */
1870
1871   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1872     {
1873       int bot, top, half;
1874       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1875
1876       field = TYPE_FIELDS (type);
1877       bot = 0;
1878       top = TYPE_LANG_SPECIFIC (type)->s->len;
1879       while (top - bot > 1)
1880         {
1881           half = (top - bot + 1) >> 1;
1882           field = field_array[bot+half];
1883
1884           if (DECL_NAME (field) == NULL_TREE)
1885             {
1886               /* Step through all anon unions in linear fashion.  */
1887               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1888                 {
1889                   field = field_array[bot++];
1890                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1891                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1892                     {
1893                       tree anon = lookup_field (field, component);
1894
1895                       if (anon)
1896                         return tree_cons (NULL_TREE, field, anon);
1897                     }
1898                 }
1899
1900               /* Entire record is only anon unions.  */
1901               if (bot > top)
1902                 return NULL_TREE;
1903
1904               /* Restart the binary search, with new lower bound.  */
1905               continue;
1906             }
1907
1908           if (DECL_NAME (field) == component)
1909             break;
1910           if (DECL_NAME (field) < component)
1911             bot += half;
1912           else
1913             top = bot + half;
1914         }
1915
1916       if (DECL_NAME (field_array[bot]) == component)
1917         field = field_array[bot];
1918       else if (DECL_NAME (field) != component)
1919         return NULL_TREE;
1920     }
1921   else
1922     {
1923       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1924         {
1925           if (DECL_NAME (field) == NULL_TREE
1926               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1927                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1928             {
1929               tree anon = lookup_field (field, component);
1930
1931               if (anon)
1932                 return tree_cons (NULL_TREE, field, anon);
1933             }
1934
1935           if (DECL_NAME (field) == component)
1936             break;
1937         }
1938
1939       if (field == NULL_TREE)
1940         return NULL_TREE;
1941     }
1942
1943   return tree_cons (NULL_TREE, field, NULL_TREE);
1944 }
1945
1946 /* Make an expression to refer to the COMPONENT field of structure or
1947    union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  LOC is the
1948    location of the COMPONENT_REF.  */
1949
1950 tree
1951 build_component_ref (location_t loc, tree datum, tree component)
1952 {
1953   tree type = TREE_TYPE (datum);
1954   enum tree_code code = TREE_CODE (type);
1955   tree field = NULL;
1956   tree ref;
1957   bool datum_lvalue = lvalue_p (datum);
1958
1959   if (!objc_is_public (datum, component))
1960     return error_mark_node;
1961
1962   /* See if there is a field or component with name COMPONENT.  */
1963
1964   if (code == RECORD_TYPE || code == UNION_TYPE)
1965     {
1966       if (!COMPLETE_TYPE_P (type))
1967         {
1968           c_incomplete_type_error (NULL_TREE, type);
1969           return error_mark_node;
1970         }
1971
1972       field = lookup_field (datum, component);
1973
1974       if (!field)
1975         {
1976           error_at (loc, "%qT has no member named %qE", type, component);
1977           return error_mark_node;
1978         }
1979
1980       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1981          This might be better solved in future the way the C++ front
1982          end does it - by giving the anonymous entities each a
1983          separate name and type, and then have build_component_ref
1984          recursively call itself.  We can't do that here.  */
1985       do
1986         {
1987           tree subdatum = TREE_VALUE (field);
1988           int quals;
1989           tree subtype;
1990           bool use_datum_quals;
1991
1992           if (TREE_TYPE (subdatum) == error_mark_node)
1993             return error_mark_node;
1994
1995           /* If this is an rvalue, it does not have qualifiers in C
1996              standard terms and we must avoid propagating such
1997              qualifiers down to a non-lvalue array that is then
1998              converted to a pointer.  */
1999           use_datum_quals = (datum_lvalue
2000                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
2001
2002           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
2003           if (use_datum_quals)
2004             quals |= TYPE_QUALS (TREE_TYPE (datum));
2005           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
2006
2007           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
2008                         NULL_TREE);
2009           SET_EXPR_LOCATION (ref, loc);
2010           if (TREE_READONLY (subdatum)
2011               || (use_datum_quals && TREE_READONLY (datum)))
2012             TREE_READONLY (ref) = 1;
2013           if (TREE_THIS_VOLATILE (subdatum)
2014               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
2015             TREE_THIS_VOLATILE (ref) = 1;
2016
2017           if (TREE_DEPRECATED (subdatum))
2018             warn_deprecated_use (subdatum, NULL_TREE);
2019
2020           datum = ref;
2021
2022           field = TREE_CHAIN (field);
2023         }
2024       while (field);
2025
2026       return ref;
2027     }
2028   else if (code != ERROR_MARK)
2029     error_at (loc,
2030               "request for member %qE in something not a structure or union",
2031               component);
2032
2033   return error_mark_node;
2034 }
2035 \f
2036 /* Given an expression PTR for a pointer, return an expression
2037    for the value pointed to.
2038    ERRORSTRING is the name of the operator to appear in error messages.
2039
2040    LOC is the location to use for the generated tree.  */
2041
2042 tree
2043 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
2044 {
2045   tree pointer = default_conversion (ptr);
2046   tree type = TREE_TYPE (pointer);
2047   tree ref;
2048
2049   if (TREE_CODE (type) == POINTER_TYPE)
2050     {
2051       if (CONVERT_EXPR_P (pointer)
2052           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2053         {
2054           /* If a warning is issued, mark it to avoid duplicates from
2055              the backend.  This only needs to be done at
2056              warn_strict_aliasing > 2.  */
2057           if (warn_strict_aliasing > 2)
2058             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2059                                          type, TREE_OPERAND (pointer, 0)))
2060               TREE_NO_WARNING (pointer) = 1;
2061         }
2062
2063       if (TREE_CODE (pointer) == ADDR_EXPR
2064           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2065               == TREE_TYPE (type)))
2066         {
2067           ref = TREE_OPERAND (pointer, 0);
2068           protected_set_expr_location (ref, loc);
2069           return ref;
2070         }
2071       else
2072         {
2073           tree t = TREE_TYPE (type);
2074
2075           ref = build1 (INDIRECT_REF, t, pointer);
2076
2077           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2078             {
2079               error_at (loc, "dereferencing pointer to incomplete type");
2080               return error_mark_node;
2081             }
2082           if (VOID_TYPE_P (t) && c_inhibit_evaluation_warnings == 0)
2083             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2084
2085           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2086              so that we get the proper error message if the result is used
2087              to assign to.  Also, &* is supposed to be a no-op.
2088              And ANSI C seems to specify that the type of the result
2089              should be the const type.  */
2090           /* A de-reference of a pointer to const is not a const.  It is valid
2091              to change it via some other pointer.  */
2092           TREE_READONLY (ref) = TYPE_READONLY (t);
2093           TREE_SIDE_EFFECTS (ref)
2094             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2095           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2096           protected_set_expr_location (ref, loc);
2097           return ref;
2098         }
2099     }
2100   else if (TREE_CODE (pointer) != ERROR_MARK)
2101     error_at (loc,
2102               "invalid type argument of %qs (have %qT)", errorstring, type);
2103   return error_mark_node;
2104 }
2105
2106 /* This handles expressions of the form "a[i]", which denotes
2107    an array reference.
2108
2109    This is logically equivalent in C to *(a+i), but we may do it differently.
2110    If A is a variable or a member, we generate a primitive ARRAY_REF.
2111    This avoids forcing the array out of registers, and can work on
2112    arrays that are not lvalues (for example, members of structures returned
2113    by functions).
2114
2115    LOC is the location to use for the returned expression.  */
2116
2117 tree
2118 build_array_ref (location_t loc, tree array, tree index)
2119 {
2120   tree ret;
2121   bool swapped = false;
2122   if (TREE_TYPE (array) == error_mark_node
2123       || TREE_TYPE (index) == error_mark_node)
2124     return error_mark_node;
2125
2126   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2127       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2128     {
2129       tree temp;
2130       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2131           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2132         {
2133           error_at (loc, "subscripted value is neither array nor pointer");
2134           return error_mark_node;
2135         }
2136       temp = array;
2137       array = index;
2138       index = temp;
2139       swapped = true;
2140     }
2141
2142   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2143     {
2144       error_at (loc, "array subscript is not an integer");
2145       return error_mark_node;
2146     }
2147
2148   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2149     {
2150       error_at (loc, "subscripted value is pointer to function");
2151       return error_mark_node;
2152     }
2153
2154   /* ??? Existing practice has been to warn only when the char
2155      index is syntactically the index, not for char[array].  */
2156   if (!swapped)
2157      warn_array_subscript_with_type_char (index);
2158
2159   /* Apply default promotions *after* noticing character types.  */
2160   index = default_conversion (index);
2161
2162   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2163
2164   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2165     {
2166       tree rval, type;
2167
2168       /* An array that is indexed by a non-constant
2169          cannot be stored in a register; we must be able to do
2170          address arithmetic on its address.
2171          Likewise an array of elements of variable size.  */
2172       if (TREE_CODE (index) != INTEGER_CST
2173           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2174               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2175         {
2176           if (!c_mark_addressable (array))
2177             return error_mark_node;
2178         }
2179       /* An array that is indexed by a constant value which is not within
2180          the array bounds cannot be stored in a register either; because we
2181          would get a crash in store_bit_field/extract_bit_field when trying
2182          to access a non-existent part of the register.  */
2183       if (TREE_CODE (index) == INTEGER_CST
2184           && TYPE_DOMAIN (TREE_TYPE (array))
2185           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2186         {
2187           if (!c_mark_addressable (array))
2188             return error_mark_node;
2189         }
2190
2191       if (pedantic)
2192         {
2193           tree foo = array;
2194           while (TREE_CODE (foo) == COMPONENT_REF)
2195             foo = TREE_OPERAND (foo, 0);
2196           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2197             pedwarn (loc, OPT_pedantic,
2198                      "ISO C forbids subscripting %<register%> array");
2199           else if (!flag_isoc99 && !lvalue_p (foo))
2200             pedwarn (loc, OPT_pedantic,
2201                      "ISO C90 forbids subscripting non-lvalue array");
2202         }
2203
2204       type = TREE_TYPE (TREE_TYPE (array));
2205       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2206       /* Array ref is const/volatile if the array elements are
2207          or if the array is.  */
2208       TREE_READONLY (rval)
2209         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2210             | TREE_READONLY (array));
2211       TREE_SIDE_EFFECTS (rval)
2212         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2213             | TREE_SIDE_EFFECTS (array));
2214       TREE_THIS_VOLATILE (rval)
2215         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2216             /* This was added by rms on 16 Nov 91.
2217                It fixes  vol struct foo *a;  a->elts[1]
2218                in an inline function.
2219                Hope it doesn't break something else.  */
2220             | TREE_THIS_VOLATILE (array));
2221       ret = require_complete_type (rval);
2222       protected_set_expr_location (ret, loc);
2223       return ret;
2224     }
2225   else
2226     {
2227       tree ar = default_conversion (array);
2228
2229       if (ar == error_mark_node)
2230         return ar;
2231
2232       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2233       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2234
2235       return build_indirect_ref
2236         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2237          "array indexing");
2238     }
2239 }
2240 \f
2241 /* Build an external reference to identifier ID.  FUN indicates
2242    whether this will be used for a function call.  LOC is the source
2243    location of the identifier.  This sets *TYPE to the type of the
2244    identifier, which is not the same as the type of the returned value
2245    for CONST_DECLs defined as enum constants.  If the type of the
2246    identifier is not available, *TYPE is set to NULL.  */
2247 tree
2248 build_external_ref (location_t loc, tree id, int fun, tree *type)
2249 {
2250   tree ref;
2251   tree decl = lookup_name (id);
2252
2253   /* In Objective-C, an instance variable (ivar) may be preferred to
2254      whatever lookup_name() found.  */
2255   decl = objc_lookup_ivar (decl, id);
2256
2257   *type = NULL;
2258   if (decl && decl != error_mark_node)
2259     {
2260       ref = decl;
2261       *type = TREE_TYPE (ref);
2262     }
2263   else if (fun)
2264     /* Implicit function declaration.  */
2265     ref = implicitly_declare (loc, id);
2266   else if (decl == error_mark_node)
2267     /* Don't complain about something that's already been
2268        complained about.  */
2269     return error_mark_node;
2270   else
2271     {
2272       undeclared_variable (loc, id);
2273       return error_mark_node;
2274     }
2275
2276   if (TREE_TYPE (ref) == error_mark_node)
2277     return error_mark_node;
2278
2279   if (TREE_DEPRECATED (ref))
2280     warn_deprecated_use (ref, NULL_TREE);
2281
2282   /* Recursive call does not count as usage.  */
2283   if (ref != current_function_decl)
2284     {
2285       TREE_USED (ref) = 1;
2286     }
2287
2288   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2289     {
2290       if (!in_sizeof && !in_typeof)
2291         C_DECL_USED (ref) = 1;
2292       else if (DECL_INITIAL (ref) == 0
2293                && DECL_EXTERNAL (ref)
2294                && !TREE_PUBLIC (ref))
2295         record_maybe_used_decl (ref);
2296     }
2297
2298   if (TREE_CODE (ref) == CONST_DECL)
2299     {
2300       used_types_insert (TREE_TYPE (ref));
2301
2302       if (warn_cxx_compat
2303           && TREE_CODE (TREE_TYPE (ref)) == ENUMERAL_TYPE
2304           && C_TYPE_DEFINED_IN_STRUCT (TREE_TYPE (ref)))
2305         {
2306           warning_at (loc, OPT_Wc___compat,
2307                       ("enum constant defined in struct or union "
2308                        "is not visible in C++"));
2309           inform (DECL_SOURCE_LOCATION (ref), "enum constant defined here");
2310         }
2311
2312       ref = DECL_INITIAL (ref);
2313       TREE_CONSTANT (ref) = 1;
2314     }
2315   else if (current_function_decl != 0
2316            && !DECL_FILE_SCOPE_P (current_function_decl)
2317            && (TREE_CODE (ref) == VAR_DECL
2318                || TREE_CODE (ref) == PARM_DECL
2319                || TREE_CODE (ref) == FUNCTION_DECL))
2320     {
2321       tree context = decl_function_context (ref);
2322
2323       if (context != 0 && context != current_function_decl)
2324         DECL_NONLOCAL (ref) = 1;
2325     }
2326   /* C99 6.7.4p3: An inline definition of a function with external
2327      linkage ... shall not contain a reference to an identifier with
2328      internal linkage.  */
2329   else if (current_function_decl != 0
2330            && DECL_DECLARED_INLINE_P (current_function_decl)
2331            && DECL_EXTERNAL (current_function_decl)
2332            && VAR_OR_FUNCTION_DECL_P (ref)
2333            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2334            && ! TREE_PUBLIC (ref)
2335            && DECL_CONTEXT (ref) != current_function_decl)
2336     record_inline_static (loc, current_function_decl, ref,
2337                           csi_internal);
2338
2339   return ref;
2340 }
2341
2342 /* Record details of decls possibly used inside sizeof or typeof.  */
2343 struct maybe_used_decl
2344 {
2345   /* The decl.  */
2346   tree decl;
2347   /* The level seen at (in_sizeof + in_typeof).  */
2348   int level;
2349   /* The next one at this level or above, or NULL.  */
2350   struct maybe_used_decl *next;
2351 };
2352
2353 static struct maybe_used_decl *maybe_used_decls;
2354
2355 /* Record that DECL, an undefined static function reference seen
2356    inside sizeof or typeof, might be used if the operand of sizeof is
2357    a VLA type or the operand of typeof is a variably modified
2358    type.  */
2359
2360 static void
2361 record_maybe_used_decl (tree decl)
2362 {
2363   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2364   t->decl = decl;
2365   t->level = in_sizeof + in_typeof;
2366   t->next = maybe_used_decls;
2367   maybe_used_decls = t;
2368 }
2369
2370 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2371    USED is false, just discard them.  If it is true, mark them used
2372    (if no longer inside sizeof or typeof) or move them to the next
2373    level up (if still inside sizeof or typeof).  */
2374
2375 void
2376 pop_maybe_used (bool used)
2377 {
2378   struct maybe_used_decl *p = maybe_used_decls;
2379   int cur_level = in_sizeof + in_typeof;
2380   while (p && p->level > cur_level)
2381     {
2382       if (used)
2383         {
2384           if (cur_level == 0)
2385             C_DECL_USED (p->decl) = 1;
2386           else
2387             p->level = cur_level;
2388         }
2389       p = p->next;
2390     }
2391   if (!used || cur_level == 0)
2392     maybe_used_decls = p;
2393 }
2394
2395 /* Return the result of sizeof applied to EXPR.  */
2396
2397 struct c_expr
2398 c_expr_sizeof_expr (location_t loc, struct c_expr expr)
2399 {
2400   struct c_expr ret;
2401   if (expr.value == error_mark_node)
2402     {
2403       ret.value = error_mark_node;
2404       ret.original_code = ERROR_MARK;
2405       ret.original_type = NULL;
2406       pop_maybe_used (false);
2407     }
2408   else
2409     {
2410       bool expr_const_operands = true;
2411       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2412                                        &expr_const_operands);
2413       ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));
2414       ret.original_code = ERROR_MARK;
2415       ret.original_type = NULL;
2416       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2417         {
2418           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2419           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2420                               folded_expr, ret.value);
2421           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2422           SET_EXPR_LOCATION (ret.value, loc);
2423         }
2424       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2425     }
2426   return ret;
2427 }
2428
2429 /* Return the result of sizeof applied to T, a structure for the type
2430    name passed to sizeof (rather than the type itself).  LOC is the
2431    location of the original expression.  */
2432
2433 struct c_expr
2434 c_expr_sizeof_type (location_t loc, struct c_type_name *t)
2435 {
2436   tree type;
2437   struct c_expr ret;
2438   tree type_expr = NULL_TREE;
2439   bool type_expr_const = true;
2440   type = groktypename (t, &type_expr, &type_expr_const);
2441   ret.value = c_sizeof (loc, type);
2442   ret.original_code = ERROR_MARK;
2443   ret.original_type = NULL;
2444   if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST)
2445       && c_vla_type_p (type))
2446     {
2447       /* If the type is a [*] array, it is a VLA but is represented as
2448          having a size of zero.  In such a case we must ensure that
2449          the result of sizeof does not get folded to a constant by
2450          c_fully_fold, because if the size is evaluated the result is
2451          not constant and so constraints on zero or negative size
2452          arrays must not be applied when this sizeof call is inside
2453          another array declarator.  */
2454       if (!type_expr)
2455         type_expr = integer_zero_node;
2456       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2457                           type_expr, ret.value);
2458       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2459     }
2460   pop_maybe_used (type != error_mark_node
2461                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2462   return ret;
2463 }
2464
2465 /* Build a function call to function FUNCTION with parameters PARAMS.
2466    The function call is at LOC.
2467    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2468    TREE_VALUE of each node is a parameter-expression.
2469    FUNCTION's data type may be a function type or a pointer-to-function.  */
2470
2471 tree
2472 build_function_call (location_t loc, tree function, tree params)
2473 {
2474   VEC(tree,gc) *vec;
2475   tree ret;
2476
2477   vec = VEC_alloc (tree, gc, list_length (params));
2478   for (; params; params = TREE_CHAIN (params))
2479     VEC_quick_push (tree, vec, TREE_VALUE (params));
2480   ret = build_function_call_vec (loc, function, vec, NULL);
2481   VEC_free (tree, gc, vec);
2482   return ret;
2483 }
2484
2485 /* Build a function call to function FUNCTION with parameters PARAMS.
2486    ORIGTYPES, if not NULL, is a vector of types; each element is
2487    either NULL or the original type of the corresponding element in
2488    PARAMS.  The original type may differ from TREE_TYPE of the
2489    parameter for enums.  FUNCTION's data type may be a function type
2490    or pointer-to-function.  This function changes the elements of
2491    PARAMS.  */
2492
2493 tree
2494 build_function_call_vec (location_t loc, tree function, VEC(tree,gc) *params,
2495                          VEC(tree,gc) *origtypes)
2496 {
2497   tree fntype, fundecl = 0;
2498   tree name = NULL_TREE, result;
2499   tree tem;
2500   int nargs;
2501   tree *argarray;
2502
2503
2504   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2505   STRIP_TYPE_NOPS (function);
2506
2507   /* Convert anything with function type to a pointer-to-function.  */
2508   if (TREE_CODE (function) == FUNCTION_DECL)
2509     {
2510       /* Implement type-directed function overloading for builtins.
2511          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2512          handle all the type checking.  The result is a complete expression
2513          that implements this function call.  */
2514       tem = resolve_overloaded_builtin (loc, function, params);
2515       if (tem)
2516         return tem;
2517
2518       name = DECL_NAME (function);
2519       fundecl = function;
2520     }
2521   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2522     function = function_to_pointer_conversion (loc, function);
2523
2524   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2525      expressions, like those used for ObjC messenger dispatches.  */
2526   if (!VEC_empty (tree, params))
2527     function = objc_rewrite_function_call (function,
2528                                            VEC_index (tree, params, 0));
2529
2530   function = c_fully_fold (function, false, NULL);
2531
2532   fntype = TREE_TYPE (function);
2533
2534   if (TREE_CODE (fntype) == ERROR_MARK)
2535     return error_mark_node;
2536
2537   if (!(TREE_CODE (fntype) == POINTER_TYPE
2538         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2539     {
2540       error_at (loc, "called object %qE is not a function", function);
2541       return error_mark_node;
2542     }
2543
2544   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2545     current_function_returns_abnormally = 1;
2546
2547   /* fntype now gets the type of function pointed to.  */
2548   fntype = TREE_TYPE (fntype);
2549
2550   /* Convert the parameters to the types declared in the
2551      function prototype, or apply default promotions.  */
2552
2553   nargs = convert_arguments (TYPE_ARG_TYPES (fntype), params, origtypes,
2554                              function, fundecl);
2555   if (nargs < 0)
2556     return error_mark_node;
2557
2558   /* Check that the function is called through a compatible prototype.
2559      If it is not, replace the call by a trap, wrapped up in a compound
2560      expression if necessary.  This has the nice side-effect to prevent
2561      the tree-inliner from generating invalid assignment trees which may
2562      blow up in the RTL expander later.  */
2563   if (CONVERT_EXPR_P (function)
2564       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2565       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2566       && !comptypes (fntype, TREE_TYPE (tem)))
2567     {
2568       tree return_type = TREE_TYPE (fntype);
2569       tree trap = build_function_call (loc, built_in_decls[BUILT_IN_TRAP],
2570                                        NULL_TREE);
2571       int i;
2572
2573       /* This situation leads to run-time undefined behavior.  We can't,
2574          therefore, simply error unless we can prove that all possible
2575          executions of the program must execute the code.  */
2576       if (warning_at (loc, 0, "function called through a non-compatible type"))
2577         /* We can, however, treat "undefined" any way we please.
2578            Call abort to encourage the user to fix the program.  */
2579         inform (loc, "if this code is reached, the program will abort");
2580       /* Before the abort, allow the function arguments to exit or
2581          call longjmp.  */
2582       for (i = 0; i < nargs; i++)
2583         trap = build2 (COMPOUND_EXPR, void_type_node,
2584                        VEC_index (tree, params, i), trap);
2585
2586       if (VOID_TYPE_P (return_type))
2587         {
2588           if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
2589             pedwarn (input_location, 0,
2590                      "function with qualified void return type called");
2591           return trap;
2592         }
2593       else
2594         {
2595           tree rhs;
2596
2597           if (AGGREGATE_TYPE_P (return_type))
2598             rhs = build_compound_literal (loc, return_type,
2599                                           build_constructor (return_type, 0),
2600                                           false);
2601           else
2602             rhs = fold_convert (return_type, integer_zero_node);
2603
2604           return require_complete_type (build2 (COMPOUND_EXPR, return_type,
2605                                                 trap, rhs));
2606         }
2607     }
2608
2609   argarray = VEC_address (tree, params);
2610
2611   /* Check that arguments to builtin functions match the expectations.  */
2612   if (fundecl
2613       && DECL_BUILT_IN (fundecl)
2614       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2615       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2616     return error_mark_node;
2617
2618   /* Check that the arguments to the function are valid.  */
2619   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2620                             TYPE_ARG_TYPES (fntype));
2621
2622   if (name != NULL_TREE
2623       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2624     {
2625       if (require_constant_value)
2626         result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2627                                                     function, nargs, argarray);
2628       else
2629         result = fold_build_call_array (TREE_TYPE (fntype),
2630                                         function, nargs, argarray);
2631       if (TREE_CODE (result) == NOP_EXPR
2632           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2633         STRIP_TYPE_NOPS (result);
2634     }
2635   else
2636     result = build_call_array (TREE_TYPE (fntype),
2637                                function, nargs, argarray);
2638
2639   if (VOID_TYPE_P (TREE_TYPE (result)))
2640     {
2641       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)
2642         pedwarn (input_location, 0,
2643                  "function with qualified void return type called");
2644       return result;
2645     }
2646   return require_complete_type (result);
2647 }
2648 \f
2649 /* Convert the argument expressions in the vector VALUES
2650    to the types in the list TYPELIST.
2651
2652    If TYPELIST is exhausted, or when an element has NULL as its type,
2653    perform the default conversions.
2654
2655    ORIGTYPES is the original types of the expressions in VALUES.  This
2656    holds the type of enum values which have been converted to integral
2657    types.  It may be NULL.
2658
2659    FUNCTION is a tree for the called function.  It is used only for
2660    error messages, where it is formatted with %qE.
2661
2662    This is also where warnings about wrong number of args are generated.
2663
2664    Returns the actual number of arguments processed (which may be less
2665    than the length of VALUES in some error situations), or -1 on
2666    failure.  */
2667
2668 static int
2669 convert_arguments (tree typelist, VEC(tree,gc) *values,
2670                    VEC(tree,gc) *origtypes, tree function, tree fundecl)
2671 {
2672   tree typetail, val;
2673   unsigned int parmnum;
2674   const bool type_generic = fundecl
2675     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2676   bool type_generic_remove_excess_precision = false;
2677   tree selector;
2678
2679   /* Change pointer to function to the function itself for
2680      diagnostics.  */
2681   if (TREE_CODE (function) == ADDR_EXPR
2682       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2683     function = TREE_OPERAND (function, 0);
2684
2685   /* Handle an ObjC selector specially for diagnostics.  */
2686   selector = objc_message_selector ();
2687
2688   /* For type-generic built-in functions, determine whether excess
2689      precision should be removed (classification) or not
2690      (comparison).  */
2691   if (type_generic
2692       && DECL_BUILT_IN (fundecl)
2693       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2694     {
2695       switch (DECL_FUNCTION_CODE (fundecl))
2696         {
2697         case BUILT_IN_ISFINITE:
2698         case BUILT_IN_ISINF:
2699         case BUILT_IN_ISINF_SIGN:
2700         case BUILT_IN_ISNAN:
2701         case BUILT_IN_ISNORMAL:
2702         case BUILT_IN_FPCLASSIFY:
2703           type_generic_remove_excess_precision = true;
2704           break;
2705
2706         default:
2707           type_generic_remove_excess_precision = false;
2708           break;
2709         }
2710     }
2711
2712   /* Scan the given expressions and types, producing individual
2713      converted arguments.  */
2714
2715   for (typetail = typelist, parmnum = 0;
2716        VEC_iterate (tree, values, parmnum, val);
2717        ++parmnum)
2718     {
2719       tree type = typetail ? TREE_VALUE (typetail) : 0;
2720       tree valtype = TREE_TYPE (val);
2721       tree rname = function;
2722       int argnum = parmnum + 1;
2723       const char *invalid_func_diag;
2724       bool excess_precision = false;
2725       bool npc;
2726       tree parmval;
2727
2728       if (type == void_type_node)
2729         {
2730           error ("too many arguments to function %qE", function);
2731           return parmnum;
2732         }
2733
2734       if (selector && argnum > 2)
2735         {
2736           rname = selector;
2737           argnum -= 2;
2738         }
2739
2740       npc = null_pointer_constant_p (val);
2741
2742       /* If there is excess precision and a prototype, convert once to
2743          the required type rather than converting via the semantic
2744          type.  Likewise without a prototype a float value represented
2745          as long double should be converted once to double.  But for
2746          type-generic classification functions excess precision must
2747          be removed here.  */
2748       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2749           && (type || !type_generic || !type_generic_remove_excess_precision))
2750         {
2751           val = TREE_OPERAND (val, 0);
2752           excess_precision = true;
2753         }
2754       val = c_fully_fold (val, false, NULL);
2755       STRIP_TYPE_NOPS (val);
2756
2757       val = require_complete_type (val);
2758
2759       if (type != 0)
2760         {
2761           /* Formal parm type is specified by a function prototype.  */
2762
2763           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2764             {
2765               error ("type of formal parameter %d is incomplete", parmnum + 1);
2766               parmval = val;
2767             }
2768           else
2769             {
2770               tree origtype;
2771
2772               /* Optionally warn about conversions that
2773                  differ from the default conversions.  */
2774               if (warn_traditional_conversion || warn_traditional)
2775                 {
2776                   unsigned int formal_prec = TYPE_PRECISION (type);
2777
2778                   if (INTEGRAL_TYPE_P (type)
2779                       && TREE_CODE (valtype) == REAL_TYPE)
2780                     warning (0, "passing argument %d of %qE as integer "
2781                              "rather than floating due to prototype",
2782                              argnum, rname);
2783                   if (INTEGRAL_TYPE_P (type)
2784                       && TREE_CODE (valtype) == COMPLEX_TYPE)
2785                     warning (0, "passing argument %d of %qE as integer "
2786                              "rather than complex due to prototype",
2787                              argnum, rname);
2788                   else if (TREE_CODE (type) == COMPLEX_TYPE
2789                            && TREE_CODE (valtype) == REAL_TYPE)
2790                     warning (0, "passing argument %d of %qE as complex "
2791                              "rather than floating due to prototype",
2792                              argnum, rname);
2793                   else if (TREE_CODE (type) == REAL_TYPE
2794                            && INTEGRAL_TYPE_P (valtype))
2795                     warning (0, "passing argument %d of %qE as floating "
2796                              "rather than integer due to prototype",
2797                              argnum, rname);
2798                   else if (TREE_CODE (type) == COMPLEX_TYPE
2799                            && INTEGRAL_TYPE_P (valtype))
2800                     warning (0, "passing argument %d of %qE as complex "
2801                              "rather than integer due to prototype",
2802                              argnum, rname);
2803                   else if (TREE_CODE (type) == REAL_TYPE
2804                            && TREE_CODE (valtype) == COMPLEX_TYPE)
2805                     warning (0, "passing argument %d of %qE as floating "
2806                              "rather than complex due to prototype",
2807                              argnum, rname);
2808                   /* ??? At some point, messages should be written about
2809                      conversions between complex types, but that's too messy
2810                      to do now.  */
2811                   else if (TREE_CODE (type) == REAL_TYPE
2812                            && TREE_CODE (valtype) == REAL_TYPE)
2813                     {
2814                       /* Warn if any argument is passed as `float',
2815                          since without a prototype it would be `double'.  */
2816                       if (formal_prec == TYPE_PRECISION (float_type_node)
2817                           && type != dfloat32_type_node)
2818                         warning (0, "passing argument %d of %qE as %<float%> "
2819                                  "rather than %<double%> due to prototype",
2820                                  argnum, rname);
2821
2822                       /* Warn if mismatch between argument and prototype
2823                          for decimal float types.  Warn of conversions with
2824                          binary float types and of precision narrowing due to
2825                          prototype. */
2826                       else if (type != valtype
2827                                && (type == dfloat32_type_node
2828                                    || type == dfloat64_type_node
2829                                    || type == dfloat128_type_node
2830                                    || valtype == dfloat32_type_node
2831                                    || valtype == dfloat64_type_node
2832                                    || valtype == dfloat128_type_node)
2833                                && (formal_prec
2834                                    <= TYPE_PRECISION (valtype)
2835                                    || (type == dfloat128_type_node
2836                                        && (valtype
2837                                            != dfloat64_type_node
2838                                            && (valtype
2839                                                != dfloat32_type_node)))
2840                                    || (type == dfloat64_type_node
2841                                        && (valtype
2842                                            != dfloat32_type_node))))
2843                         warning (0, "passing argument %d of %qE as %qT "
2844                                  "rather than %qT due to prototype",
2845                                  argnum, rname, type, valtype);
2846
2847                     }
2848                   /* Detect integer changing in width or signedness.
2849                      These warnings are only activated with
2850                      -Wtraditional-conversion, not with -Wtraditional.  */
2851                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2852                            && INTEGRAL_TYPE_P (valtype))
2853                     {
2854                       tree would_have_been = default_conversion (val);
2855                       tree type1 = TREE_TYPE (would_have_been);
2856
2857                       if (TREE_CODE (type) == ENUMERAL_TYPE
2858                           && (TYPE_MAIN_VARIANT (type)
2859                               == TYPE_MAIN_VARIANT (valtype)))
2860                         /* No warning if function asks for enum
2861                            and the actual arg is that enum type.  */
2862                         ;
2863                       else if (formal_prec != TYPE_PRECISION (type1))
2864                         warning (OPT_Wtraditional_conversion,
2865                                  "passing argument %d of %qE "
2866                                  "with different width due to prototype",
2867                                  argnum, rname);
2868                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2869                         ;
2870                       /* Don't complain if the formal parameter type
2871                          is an enum, because we can't tell now whether
2872                          the value was an enum--even the same enum.  */
2873                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2874                         ;
2875                       else if (TREE_CODE (val) == INTEGER_CST
2876                                && int_fits_type_p (val, type))
2877                         /* Change in signedness doesn't matter
2878                            if a constant value is unaffected.  */
2879                         ;
2880                       /* If the value is extended from a narrower
2881                          unsigned type, it doesn't matter whether we
2882                          pass it as signed or unsigned; the value
2883                          certainly is the same either way.  */
2884                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
2885                                && TYPE_UNSIGNED (valtype))
2886                         ;
2887                       else if (TYPE_UNSIGNED (type))
2888                         warning (OPT_Wtraditional_conversion,
2889                                  "passing argument %d of %qE "
2890                                  "as unsigned due to prototype",
2891                                  argnum, rname);
2892                       else
2893                         warning (OPT_Wtraditional_conversion,
2894                                  "passing argument %d of %qE "
2895                                  "as signed due to prototype", argnum, rname);
2896                     }
2897                 }
2898
2899               /* Possibly restore an EXCESS_PRECISION_EXPR for the
2900                  sake of better warnings from convert_and_check.  */
2901               if (excess_precision)
2902                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
2903               origtype = (origtypes == NULL
2904                           ? NULL_TREE
2905                           : VEC_index (tree, origtypes, parmnum));
2906               parmval = convert_for_assignment (input_location, type, val,
2907                                                 origtype, ic_argpass, npc,
2908                                                 fundecl, function,
2909                                                 parmnum + 1);
2910
2911               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2912                   && INTEGRAL_TYPE_P (type)
2913                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2914                 parmval = default_conversion (parmval);
2915             }
2916         }
2917       else if (TREE_CODE (valtype) == REAL_TYPE
2918                && (TYPE_PRECISION (valtype)
2919                    < TYPE_PRECISION (double_type_node))
2920                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
2921         {
2922           if (type_generic)
2923             parmval = val;
2924           else
2925             /* Convert `float' to `double'.  */
2926             parmval = convert (double_type_node, val);
2927         }
2928       else if (excess_precision && !type_generic)
2929         /* A "double" argument with excess precision being passed
2930            without a prototype or in variable arguments.  */
2931         parmval = convert (valtype, val);
2932       else if ((invalid_func_diag =
2933                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2934         {
2935           error (invalid_func_diag);
2936           return -1;
2937         }
2938       else
2939         /* Convert `short' and `char' to full-size `int'.  */
2940         parmval = default_conversion (val);
2941
2942       VEC_replace (tree, values, parmnum, parmval);
2943
2944       if (typetail)
2945         typetail = TREE_CHAIN (typetail);
2946     }
2947
2948   gcc_assert (parmnum == VEC_length (tree, values));
2949
2950   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2951     {
2952       error ("too few arguments to function %qE", function);
2953       return -1;
2954     }
2955
2956   return parmnum;
2957 }
2958 \f
2959 /* This is the entry point used by the parser to build unary operators
2960    in the input.  CODE, a tree_code, specifies the unary operator, and
2961    ARG is the operand.  For unary plus, the C parser currently uses
2962    CONVERT_EXPR for code.
2963
2964    LOC is the location to use for the tree generated.
2965 */
2966
2967 struct c_expr
2968 parser_build_unary_op (location_t loc, enum tree_code code, struct c_expr arg)
2969 {
2970   struct c_expr result;
2971
2972   result.value = build_unary_op (loc, code, arg.value, 0);
2973   result.original_code = code;
2974   result.original_type = NULL;
2975
2976   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2977     overflow_warning (loc, result.value);
2978
2979   return result;
2980 }
2981
2982 /* This is the entry point used by the parser to build binary operators
2983    in the input.  CODE, a tree_code, specifies the binary operator, and
2984    ARG1 and ARG2 are the operands.  In addition to constructing the
2985    expression, we check for operands that were written with other binary
2986    operators in a way that is likely to confuse the user.
2987
2988    LOCATION is the location of the binary operator.  */
2989
2990 struct c_expr
2991 parser_build_binary_op (location_t location, enum tree_code code,
2992                         struct c_expr arg1, struct c_expr arg2)
2993 {
2994   struct c_expr result;
2995
2996   enum tree_code code1 = arg1.original_code;
2997   enum tree_code code2 = arg2.original_code;
2998   tree type1 = (arg1.original_type
2999                 ? arg1.original_type
3000                 : TREE_TYPE (arg1.value));
3001   tree type2 = (arg2.original_type
3002                 ? arg2.original_type
3003                 : TREE_TYPE (arg2.value));
3004
3005   result.value = build_binary_op (location, code,
3006                                   arg1.value, arg2.value, 1);
3007   result.original_code = code;
3008   result.original_type = NULL;
3009
3010   if (TREE_CODE (result.value) == ERROR_MARK)
3011     return result;
3012
3013   if (location != UNKNOWN_LOCATION)
3014     protected_set_expr_location (result.value, location);
3015
3016   /* Check for cases such as x+y<<z which users are likely
3017      to misinterpret.  */
3018   if (warn_parentheses)
3019     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
3020
3021   if (warn_logical_op)
3022     warn_logical_operator (input_location, code, TREE_TYPE (result.value),
3023                            code1, arg1.value, code2, arg2.value);
3024
3025   /* Warn about comparisons against string literals, with the exception
3026      of testing for equality or inequality of a string literal with NULL.  */
3027   if (code == EQ_EXPR || code == NE_EXPR)
3028     {
3029       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
3030           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
3031         warning_at (location, OPT_Waddress,
3032                     "comparison with string literal results in unspecified behavior");
3033     }
3034   else if (TREE_CODE_CLASS (code) == tcc_comparison
3035            && (code1 == STRING_CST || code2 == STRING_CST))
3036     warning_at (location, OPT_Waddress,
3037                 "comparison with string literal results in unspecified behavior");
3038
3039   if (TREE_OVERFLOW_P (result.value)
3040       && !TREE_OVERFLOW_P (arg1.value)
3041       && !TREE_OVERFLOW_P (arg2.value))
3042     overflow_warning (location, result.value);
3043
3044   /* Warn about comparisons of different enum types.  */
3045   if (warn_enum_compare
3046       && TREE_CODE_CLASS (code) == tcc_comparison
3047       && TREE_CODE (type1) == ENUMERAL_TYPE
3048       && TREE_CODE (type2) == ENUMERAL_TYPE
3049       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
3050     warning_at (location, OPT_Wenum_compare,
3051                 "comparison between %qT and %qT",
3052                 type1, type2);
3053
3054   return result;
3055 }
3056 \f
3057 /* Return a tree for the difference of pointers OP0 and OP1.
3058    The resulting tree has type int.  */
3059
3060 static tree
3061 pointer_diff (tree op0, tree op1)
3062 {
3063   tree restype = ptrdiff_type_node;
3064
3065   tree target_type = TREE_TYPE (TREE_TYPE (op0));
3066   tree con0, con1, lit0, lit1;
3067   tree orig_op1 = op1;
3068
3069   if (TREE_CODE (target_type) == VOID_TYPE)
3070     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3071              "pointer of type %<void *%> used in subtraction");
3072   if (TREE_CODE (target_type) == FUNCTION_TYPE)
3073     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3074              "pointer to a function used in subtraction");
3075
3076   /* If the conversion to ptrdiff_type does anything like widening or
3077      converting a partial to an integral mode, we get a convert_expression
3078      that is in the way to do any simplifications.
3079      (fold-const.c doesn't know that the extra bits won't be needed.
3080      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
3081      different mode in place.)
3082      So first try to find a common term here 'by hand'; we want to cover
3083      at least the cases that occur in legal static initializers.  */
3084   if (CONVERT_EXPR_P (op0)
3085       && (TYPE_PRECISION (TREE_TYPE (op0))
3086           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
3087     con0 = TREE_OPERAND (op0, 0);
3088   else
3089     con0 = op0;
3090   if (CONVERT_EXPR_P (op1)
3091       && (TYPE_PRECISION (TREE_TYPE (op1))
3092           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
3093     con1 = TREE_OPERAND (op1, 0);
3094   else
3095     con1 = op1;
3096
3097   if (TREE_CODE (con0) == PLUS_EXPR)
3098     {
3099       lit0 = TREE_OPERAND (con0, 1);
3100       con0 = TREE_OPERAND (con0, 0);
3101     }
3102   else
3103     lit0 = integer_zero_node;
3104
3105   if (TREE_CODE (con1) == PLUS_EXPR)
3106     {
3107       lit1 = TREE_OPERAND (con1, 1);
3108       con1 = TREE_OPERAND (con1, 0);
3109     }
3110   else
3111     lit1 = integer_zero_node;
3112
3113   if (operand_equal_p (con0, con1, 0))
3114     {
3115       op0 = lit0;
3116       op1 = lit1;
3117     }
3118
3119
3120   /* First do the subtraction as integers;
3121      then drop through to build the divide operator.
3122      Do not do default conversions on the minus operator
3123      in case restype is a short type.  */
3124
3125   op0 = build_binary_op (input_location,
3126                          MINUS_EXPR, convert (restype, op0),
3127                          convert (restype, op1), 0);
3128   /* This generates an error if op1 is pointer to incomplete type.  */
3129   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3130     error ("arithmetic on pointer to an incomplete type");
3131
3132   /* This generates an error if op0 is pointer to incomplete type.  */
3133   op1 = c_size_in_bytes (target_type);
3134
3135   /* Divide by the size, in easiest possible way.  */
3136   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
3137 }
3138 \f
3139 /* Construct and perhaps optimize a tree representation
3140    for a unary operation.  CODE, a tree_code, specifies the operation
3141    and XARG is the operand.
3142    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3143    the default promotions (such as from short to int).
3144    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3145    allows non-lvalues; this is only used to handle conversion of non-lvalue
3146    arrays to pointers in C99.
3147
3148    LOCATION is the location of the operator.  */
3149
3150 tree
3151 build_unary_op (location_t location,
3152                 enum tree_code code, tree xarg, int flag)
3153 {
3154   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3155   tree arg = xarg;
3156   tree argtype = 0;
3157   enum tree_code typecode;
3158   tree val;
3159   tree ret = error_mark_node;
3160   tree eptype = NULL_TREE;
3161   int noconvert = flag;
3162   const char *invalid_op_diag;
3163   bool int_operands;
3164
3165   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3166   if (int_operands)
3167     arg = remove_c_maybe_const_expr (arg);
3168
3169   if (code != ADDR_EXPR)
3170     arg = require_complete_type (arg);
3171
3172   typecode = TREE_CODE (TREE_TYPE (arg));
3173   if (typecode == ERROR_MARK)
3174     return error_mark_node;
3175   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3176     typecode = INTEGER_TYPE;
3177
3178   if ((invalid_op_diag
3179        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3180     {
3181       error_at (location, invalid_op_diag);
3182       return error_mark_node;
3183     }
3184
3185   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3186     {
3187       eptype = TREE_TYPE (arg);
3188       arg = TREE_OPERAND (arg, 0);
3189     }
3190
3191   switch (code)
3192     {
3193     case CONVERT_EXPR:
3194       /* This is used for unary plus, because a CONVERT_EXPR
3195          is enough to prevent anybody from looking inside for
3196          associativity, but won't generate any code.  */
3197       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3198             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3199             || typecode == VECTOR_TYPE))
3200         {
3201           error_at (location, "wrong type argument to unary plus");
3202           return error_mark_node;
3203         }
3204       else if (!noconvert)
3205         arg = default_conversion (arg);
3206       arg = non_lvalue (arg);
3207       break;
3208
3209     case NEGATE_EXPR:
3210       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3211             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3212             || typecode == VECTOR_TYPE))
3213         {
3214           error_at (location, "wrong type argument to unary minus");
3215           return error_mark_node;
3216         }
3217       else if (!noconvert)
3218         arg = default_conversion (arg);
3219       break;
3220
3221     case BIT_NOT_EXPR:
3222       /* ~ works on integer types and non float vectors. */
3223       if (typecode == INTEGER_TYPE
3224           || (typecode == VECTOR_TYPE
3225               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3226         {
3227           if (!noconvert)
3228             arg = default_conversion (arg);
3229         }
3230       else if (typecode == COMPLEX_TYPE)
3231         {
3232           code = CONJ_EXPR;
3233           pedwarn (location, OPT_pedantic,
3234                    "ISO C does not support %<~%> for complex conjugation");
3235           if (!noconvert)
3236             arg = default_conversion (arg);
3237         }
3238       else
3239         {
3240           error_at (location, "wrong type argument to bit-complement");
3241           return error_mark_node;
3242         }
3243       break;
3244
3245     case ABS_EXPR:
3246       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3247         {
3248           error_at (location, "wrong type argument to abs");
3249           return error_mark_node;
3250         }
3251       else if (!noconvert)
3252         arg = default_conversion (arg);
3253       break;
3254
3255     case CONJ_EXPR:
3256       /* Conjugating a real value is a no-op, but allow it anyway.  */
3257       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3258             || typecode == COMPLEX_TYPE))
3259         {
3260           error_at (location, "wrong type argument to conjugation");
3261           return error_mark_node;
3262         }
3263       else if (!noconvert)
3264         arg = default_conversion (arg);
3265       break;
3266
3267     case TRUTH_NOT_EXPR:
3268       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3269           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3270           && typecode != COMPLEX_TYPE)
3271         {
3272           error_at (location,
3273                     "wrong type argument to unary exclamation mark");
3274           return error_mark_node;
3275         }
3276       arg = c_objc_common_truthvalue_conversion (location, arg);
3277       ret = invert_truthvalue (arg);
3278       /* If the TRUTH_NOT_EXPR has been folded, reset the location.  */
3279       if (EXPR_P (ret) && EXPR_HAS_LOCATION (ret))
3280         location = EXPR_LOCATION (ret);
3281       goto return_build_unary_op;
3282
3283     case REALPART_EXPR:
3284       if (TREE_CODE (arg) == COMPLEX_CST)
3285         ret = TREE_REALPART (arg);
3286       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3287         ret = fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3288       else
3289         ret = arg;
3290       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3291         eptype = TREE_TYPE (eptype);
3292       goto return_build_unary_op;
3293
3294     case IMAGPART_EXPR:
3295       if (TREE_CODE (arg) == COMPLEX_CST)
3296         ret = TREE_IMAGPART (arg);
3297       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3298         ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3299       else
3300         ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
3301       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3302         eptype = TREE_TYPE (eptype);
3303       goto return_build_unary_op;
3304
3305     case PREINCREMENT_EXPR:
3306     case POSTINCREMENT_EXPR:
3307     case PREDECREMENT_EXPR:
3308     case POSTDECREMENT_EXPR:
3309
3310       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3311         {
3312           tree inner = build_unary_op (location, code,
3313                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3314           if (inner == error_mark_node)
3315             return error_mark_node;
3316           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3317                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3318           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3319           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3320           goto return_build_unary_op;
3321         }
3322
3323       /* Complain about anything that is not a true lvalue.  */
3324       if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3325                                   || code == POSTINCREMENT_EXPR)
3326                                  ? lv_increment
3327                                  : lv_decrement)))
3328         return error_mark_node;
3329
3330       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3331         {
3332           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3333             warning_at (location, OPT_Wc___compat,
3334                         "increment of enumeration value is invalid in C++");
3335           else
3336             warning_at (location, OPT_Wc___compat,
3337                         "decrement of enumeration value is invalid in C++");
3338         }
3339
3340       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3341       arg = c_fully_fold (arg, false, NULL);
3342
3343       /* Increment or decrement the real part of the value,
3344          and don't change the imaginary part.  */
3345       if (typecode == COMPLEX_TYPE)
3346         {
3347           tree real, imag;
3348
3349           pedwarn (location, OPT_pedantic,
3350                    "ISO C does not support %<++%> and %<--%> on complex types");
3351
3352           arg = stabilize_reference (arg);
3353           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3354           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3355           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3356           if (real == error_mark_node || imag == error_mark_node)
3357             return error_mark_node;
3358           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3359                         real, imag);
3360           goto return_build_unary_op;
3361         }
3362
3363       /* Report invalid types.  */
3364
3365       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3366           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3367         {
3368           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3369             error_at (location, "wrong type argument to increment");
3370           else
3371             error_at (location, "wrong type argument to decrement");
3372
3373           return error_mark_node;
3374         }
3375
3376       {
3377         tree inc;
3378
3379         argtype = TREE_TYPE (arg);
3380
3381         /* Compute the increment.  */
3382
3383         if (typecode == POINTER_TYPE)
3384           {
3385             /* If pointer target is an undefined struct,
3386                we just cannot know how to do the arithmetic.  */
3387             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3388               {
3389                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3390                   error_at (location,
3391                             "increment of pointer to unknown structure");
3392                 else
3393                   error_at (location,
3394                             "decrement of pointer to unknown structure");
3395               }
3396             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3397                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3398               {
3399                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3400                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3401                            "wrong type argument to increment");
3402                 else
3403                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3404                            "wrong type argument to decrement");
3405               }
3406
3407             inc = c_size_in_bytes (TREE_TYPE (argtype));
3408             inc = fold_convert (sizetype, inc);
3409           }
3410         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3411           {
3412             /* For signed fract types, we invert ++ to -- or
3413                -- to ++, and change inc from 1 to -1, because
3414                it is not possible to represent 1 in signed fract constants.
3415                For unsigned fract types, the result always overflows and
3416                we get an undefined (original) or the maximum value.  */
3417             if (code == PREINCREMENT_EXPR)
3418               code = PREDECREMENT_EXPR;
3419             else if (code == PREDECREMENT_EXPR)
3420               code = PREINCREMENT_EXPR;
3421             else if (code == POSTINCREMENT_EXPR)
3422               code = POSTDECREMENT_EXPR;
3423             else /* code == POSTDECREMENT_EXPR  */
3424               code = POSTINCREMENT_EXPR;
3425
3426             inc = integer_minus_one_node;
3427             inc = convert (argtype, inc);
3428           }
3429         else
3430           {
3431             inc = integer_one_node;
3432             inc = convert (argtype, inc);
3433           }
3434
3435         /* Report a read-only lvalue.  */
3436         if (TYPE_READONLY (argtype))
3437           {
3438             readonly_error (arg,
3439                             ((code == PREINCREMENT_EXPR
3440                               || code == POSTINCREMENT_EXPR)
3441                              ? lv_increment : lv_decrement));
3442             return error_mark_node;
3443           }
3444         else if (TREE_READONLY (arg))
3445           readonly_warning (arg,
3446                             ((code == PREINCREMENT_EXPR
3447                               || code == POSTINCREMENT_EXPR)
3448                              ? lv_increment : lv_decrement));
3449
3450         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3451           val = boolean_increment (code, arg);
3452         else
3453           val = build2 (code, TREE_TYPE (arg), arg, inc);
3454         TREE_SIDE_EFFECTS (val) = 1;
3455         if (TREE_CODE (val) != code)
3456           TREE_NO_WARNING (val) = 1;
3457         ret = val;
3458         goto return_build_unary_op;
3459       }
3460
3461     case ADDR_EXPR:
3462       /* Note that this operation never does default_conversion.  */
3463
3464       /* The operand of unary '&' must be an lvalue (which excludes
3465          expressions of type void), or, in C99, the result of a [] or
3466          unary '*' operator.  */
3467       if (VOID_TYPE_P (TREE_TYPE (arg))
3468           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3469           && (TREE_CODE (arg) != INDIRECT_REF
3470               || !flag_isoc99))
3471         pedwarn (location, 0, "taking address of expression of type %<void%>");
3472
3473       /* Let &* cancel out to simplify resulting code.  */
3474       if (TREE_CODE (arg) == INDIRECT_REF)
3475         {
3476           /* Don't let this be an lvalue.  */
3477           if (lvalue_p (TREE_OPERAND (arg, 0)))
3478             return non_lvalue (TREE_OPERAND (arg, 0));
3479           ret = TREE_OPERAND (arg, 0);
3480           goto return_build_unary_op;
3481         }
3482
3483       /* For &x[y], return x+y */
3484       if (TREE_CODE (arg) == ARRAY_REF)
3485         {
3486           tree op0 = TREE_OPERAND (arg, 0);
3487           if (!c_mark_addressable (op0))
3488             return error_mark_node;
3489           return build_binary_op (location, PLUS_EXPR,
3490                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3491                                    ? array_to_pointer_conversion (location,
3492                                                                   op0)
3493                                    : op0),
3494                                   TREE_OPERAND (arg, 1), 1);
3495         }
3496
3497       /* Anything not already handled and not a true memory reference
3498          or a non-lvalue array is an error.  */
3499       else if (typecode != FUNCTION_TYPE && !flag
3500                && !lvalue_or_else (arg, lv_addressof))
3501         return error_mark_node;
3502
3503       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3504          folding later.  */
3505       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3506         {
3507           tree inner = build_unary_op (location, code,
3508                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3509           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3510                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3511           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3512           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3513             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3514           goto return_build_unary_op;
3515         }
3516
3517       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3518       argtype = TREE_TYPE (arg);
3519
3520       /* If the lvalue is const or volatile, merge that into the type
3521          to which the address will point.  Note that you can't get a
3522          restricted pointer by taking the address of something, so we
3523          only have to deal with `const' and `volatile' here.  */
3524       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3525           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3526           argtype = c_build_type_variant (argtype,
3527                                           TREE_READONLY (arg),
3528                                           TREE_THIS_VOLATILE (arg));
3529
3530       if (!c_mark_addressable (arg))
3531         return error_mark_node;
3532
3533       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3534                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3535
3536       argtype = build_pointer_type (argtype);
3537
3538       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3539          when we have proper support for integer constant expressions.  */
3540       val = get_base_address (arg);
3541       if (val && TREE_CODE (val) == INDIRECT_REF
3542           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3543         {
3544           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3545
3546           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3547           ret = fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3548           goto return_build_unary_op;
3549         }
3550
3551       val = build1 (ADDR_EXPR, argtype, arg);
3552
3553       ret = val;
3554       goto return_build_unary_op;
3555
3556     default:
3557       gcc_unreachable ();
3558     }
3559
3560   if (argtype == 0)
3561     argtype = TREE_TYPE (arg);
3562   if (TREE_CODE (arg) == INTEGER_CST)
3563     ret = (require_constant_value
3564            ? fold_build1_initializer (code, argtype, arg)
3565            : fold_build1 (code, argtype, arg));
3566   else
3567     ret = build1 (code, argtype, arg);
3568  return_build_unary_op:
3569   gcc_assert (ret != error_mark_node);
3570   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3571       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3572     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3573   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3574     ret = note_integer_operands (ret);
3575   if (eptype)
3576     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3577   protected_set_expr_location (ret, location);
3578   return ret;
3579 }
3580
3581 /* Return nonzero if REF is an lvalue valid for this language.
3582    Lvalues can be assigned, unless their type has TYPE_READONLY.
3583    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3584
3585 bool
3586 lvalue_p (const_tree ref)
3587 {
3588   const enum tree_code code = TREE_CODE (ref);
3589
3590   switch (code)
3591     {
3592     case REALPART_EXPR:
3593     case IMAGPART_EXPR:
3594     case COMPONENT_REF:
3595       return lvalue_p (TREE_OPERAND (ref, 0));
3596
3597     case C_MAYBE_CONST_EXPR:
3598       return lvalue_p (TREE_OPERAND (ref, 1));
3599
3600     case COMPOUND_LITERAL_EXPR:
3601     case STRING_CST:
3602       return 1;
3603
3604     case INDIRECT_REF:
3605     case ARRAY_REF:
3606     case VAR_DECL:
3607     case PARM_DECL:
3608     case RESULT_DECL:
3609     case ERROR_MARK:
3610       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3611               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3612
3613     case BIND_EXPR:
3614       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3615
3616     default:
3617       return 0;
3618     }
3619 }
3620 \f
3621 /* Give an error for storing in something that is 'const'.  */
3622
3623 static void
3624 readonly_error (tree arg, enum lvalue_use use)
3625 {
3626   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3627               || use == lv_asm);
3628   /* Using this macro rather than (for example) arrays of messages
3629      ensures that all the format strings are checked at compile
3630      time.  */
3631 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3632                                    : (use == lv_increment ? (I)         \
3633                                    : (use == lv_decrement ? (D) : (AS))))
3634   if (TREE_CODE (arg) == COMPONENT_REF)
3635     {
3636       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3637         readonly_error (TREE_OPERAND (arg, 0), use);
3638       else
3639         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3640                              G_("increment of read-only member %qD"),
3641                              G_("decrement of read-only member %qD"),
3642                              G_("read-only member %qD used as %<asm%> output")),
3643                TREE_OPERAND (arg, 1));
3644     }
3645   else if (TREE_CODE (arg) == VAR_DECL)
3646     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3647                          G_("increment of read-only variable %qD"),
3648                          G_("decrement of read-only variable %qD"),
3649                          G_("read-only variable %qD used as %<asm%> output")),
3650            arg);
3651   else
3652     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3653                          G_("increment of read-only location %qE"),
3654                          G_("decrement of read-only location %qE"),
3655                          G_("read-only location %qE used as %<asm%> output")),
3656            arg);
3657 }
3658
3659 /* Give a warning for storing in something that is read-only in GCC
3660    terms but not const in ISO C terms.  */
3661
3662 static void
3663 readonly_warning (tree arg, enum lvalue_use use)
3664 {
3665   switch (use)
3666     {
3667     case lv_assign:
3668       warning (0, "assignment of read-only location %qE", arg);
3669       break;
3670     case lv_increment:
3671       warning (0, "increment of read-only location %qE", arg);
3672       break;
3673     case lv_decrement:
3674       warning (0, "decrement of read-only location %qE", arg);
3675       break;
3676     default:
3677       gcc_unreachable ();
3678     }
3679   return;
3680 }
3681
3682
3683 /* Return nonzero if REF is an lvalue valid for this language;
3684    otherwise, print an error message and return zero.  USE says
3685    how the lvalue is being used and so selects the error message.  */
3686
3687 static int
3688 lvalue_or_else (const_tree ref, enum lvalue_use use)
3689 {
3690   int win = lvalue_p (ref);
3691
3692   if (!win)
3693     lvalue_error (use);
3694
3695   return win;
3696 }
3697 \f
3698 /* Mark EXP saying that we need to be able to take the
3699    address of it; it should not be allocated in a register.
3700    Returns true if successful.  */
3701
3702 bool
3703 c_mark_addressable (tree exp)
3704 {
3705   tree x = exp;
3706
3707   while (1)
3708     switch (TREE_CODE (x))
3709       {
3710       case COMPONENT_REF:
3711         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3712           {
3713             error
3714               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3715             return false;
3716           }
3717
3718         /* ... fall through ...  */
3719
3720       case ADDR_EXPR:
3721       case ARRAY_REF:
3722       case REALPART_EXPR:
3723       case IMAGPART_EXPR:
3724         x = TREE_OPERAND (x, 0);
3725         break;
3726
3727       case COMPOUND_LITERAL_EXPR:
3728       case CONSTRUCTOR:
3729         TREE_ADDRESSABLE (x) = 1;
3730         return true;
3731
3732       case VAR_DECL:
3733       case CONST_DECL:
3734       case PARM_DECL:
3735       case RESULT_DECL:
3736         if (C_DECL_REGISTER (x)
3737             && DECL_NONLOCAL (x))
3738           {
3739             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3740               {
3741                 error
3742                   ("global register variable %qD used in nested function", x);
3743                 return false;
3744               }
3745             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3746           }
3747         else if (C_DECL_REGISTER (x))
3748           {
3749             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3750               error ("address of global register variable %qD requested", x);
3751             else
3752               error ("address of register variable %qD requested", x);
3753             return false;
3754           }
3755
3756         /* drops in */
3757       case FUNCTION_DECL:
3758         TREE_ADDRESSABLE (x) = 1;
3759         /* drops out */
3760       default:
3761         return true;
3762     }
3763 }
3764 \f
3765 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
3766    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
3767    if folded to an integer constant then the unselected half may
3768    contain arbitrary operations not normally permitted in constant
3769    expressions.  Set the location of the expression to LOC.  */
3770
3771 tree
3772 build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
3773                         tree op1, tree op1_original_type, tree op2,
3774                         tree op2_original_type)
3775 {
3776   tree type1;
3777   tree type2;
3778   enum tree_code code1;
3779   enum tree_code code2;
3780   tree result_type = NULL;
3781   tree ep_result_type = NULL;
3782   tree orig_op1 = op1, orig_op2 = op2;
3783   bool int_const, op1_int_operands, op2_int_operands, int_operands;
3784   bool ifexp_int_operands;
3785   tree ret;
3786   bool objc_ok;
3787
3788   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
3789   if (op1_int_operands)
3790     op1 = remove_c_maybe_const_expr (op1);
3791   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
3792   if (op2_int_operands)
3793     op2 = remove_c_maybe_const_expr (op2);
3794   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
3795   if (ifexp_int_operands)
3796     ifexp = remove_c_maybe_const_expr (ifexp);
3797
3798   /* Promote both alternatives.  */
3799
3800   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3801     op1 = default_conversion (op1);
3802   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3803     op2 = default_conversion (op2);
3804
3805   if (TREE_CODE (ifexp) == ERROR_MARK
3806       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3807       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3808     return error_mark_node;
3809
3810   type1 = TREE_TYPE (op1);
3811   code1 = TREE_CODE (type1);
3812   type2 = TREE_TYPE (op2);
3813   code2 = TREE_CODE (type2);
3814
3815   /* C90 does not permit non-lvalue arrays in conditional expressions.
3816      In C99 they will be pointers by now.  */
3817   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3818     {
3819       error_at (colon_loc, "non-lvalue array in conditional expression");
3820       return error_mark_node;
3821     }
3822
3823   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3824
3825   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
3826        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3827       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3828           || code1 == COMPLEX_TYPE)
3829       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3830           || code2 == COMPLEX_TYPE))
3831     {
3832       ep_result_type = c_common_type (type1, type2);
3833       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
3834         {
3835           op1 = TREE_OPERAND (op1, 0);
3836           type1 = TREE_TYPE (op1);
3837           gcc_assert (TREE_CODE (type1) == code1);
3838         }
3839       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3840         {
3841           op2 = TREE_OPERAND (op2, 0);
3842           type2 = TREE_TYPE (op2);
3843           gcc_assert (TREE_CODE (type2) == code2);
3844         }
3845     }
3846
3847   if (warn_cxx_compat)
3848     {
3849       tree t1 = op1_original_type ? op1_original_type : TREE_TYPE (orig_op1);
3850       tree t2 = op2_original_type ? op2_original_type : TREE_TYPE (orig_op2);
3851
3852       if (TREE_CODE (t1) == ENUMERAL_TYPE
3853           && TREE_CODE (t2) == ENUMERAL_TYPE
3854           && TYPE_MAIN_VARIANT (t1) != TYPE_MAIN_VARIANT (t2))
3855         warning_at (colon_loc, OPT_Wc___compat,
3856                     ("different enum types in conditional is "
3857                      "invalid in C++: %qT vs %qT"),
3858                     t1, t2);
3859     }
3860
3861   /* Quickly detect the usual case where op1 and op2 have the same type
3862      after promotion.  */
3863   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3864     {
3865       if (type1 == type2)
3866         result_type = type1;
3867       else
3868         result_type = TYPE_MAIN_VARIANT (type1);
3869     }
3870   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3871             || code1 == COMPLEX_TYPE)
3872            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3873                || code2 == COMPLEX_TYPE))
3874     {
3875       result_type = c_common_type (type1, type2);
3876
3877       /* If -Wsign-compare, warn here if type1 and type2 have
3878          different signedness.  We'll promote the signed to unsigned
3879          and later code won't know it used to be different.
3880          Do this check on the original types, so that explicit casts
3881          will be considered, but default promotions won't.  */
3882       if (c_inhibit_evaluation_warnings == 0)
3883         {
3884           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3885           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3886
3887           if (unsigned_op1 ^ unsigned_op2)
3888             {
3889               bool ovf;
3890
3891               /* Do not warn if the result type is signed, since the
3892                  signed type will only be chosen if it can represent
3893                  all the values of the unsigned type.  */
3894               if (!TYPE_UNSIGNED (result_type))
3895                 /* OK */;
3896               else
3897                 {
3898                   bool op1_maybe_const = true;
3899                   bool op2_maybe_const = true;
3900
3901                   /* Do not warn if the signed quantity is an
3902                      unsuffixed integer literal (or some static
3903                      constant expression involving such literals) and
3904                      it is non-negative.  This warning requires the
3905                      operands to be folded for best results, so do
3906                      that folding in this case even without
3907                      warn_sign_compare to avoid warning options
3908                      possibly affecting code generation.  */
3909                   op1 = c_fully_fold (op1, require_constant_value,
3910                                       &op1_maybe_const);
3911                   op2 = c_fully_fold (op2, require_constant_value,
3912                                       &op2_maybe_const);
3913
3914                   if (warn_sign_compare)
3915                     {
3916                       if ((unsigned_op2
3917                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
3918                           || (unsigned_op1
3919                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3920                         /* OK */;
3921                       else
3922                         warning_at (colon_loc, OPT_Wsign_compare,
3923                                     ("signed and unsigned type in "
3924                                      "conditional expression"));
3925                     }
3926                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
3927                     {
3928                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
3929                                     NULL, op1);
3930                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
3931                     }
3932                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
3933                     {
3934                       op2 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op2),
3935                                     NULL, op2);
3936                       C_MAYBE_CONST_EXPR_NON_CONST (op2) = !op2_maybe_const;
3937                     }
3938                 }
3939             }
3940         }
3941     }
3942   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3943     {
3944       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3945         pedwarn (colon_loc, OPT_pedantic,
3946                  "ISO C forbids conditional expr with only one void side");
3947       result_type = void_type_node;
3948     }
3949   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3950     {
3951       if (comp_target_types (colon_loc, type1, type2))
3952         result_type = common_pointer_type (type1, type2);
3953       else if (null_pointer_constant_p (orig_op1))
3954         result_type = qualify_type (type2, type1);
3955       else if (null_pointer_constant_p (orig_op2))
3956         result_type = qualify_type (type1, type2);
3957       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3958         {
3959           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3960             pedwarn (colon_loc, OPT_pedantic,
3961                      "ISO C forbids conditional expr between "
3962                      "%<void *%> and function pointer");
3963           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3964                                                           TREE_TYPE (type2)));
3965         }
3966       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3967         {
3968           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3969             pedwarn (colon_loc, OPT_pedantic,
3970                      "ISO C forbids conditional expr between "
3971                      "%<void *%> and function pointer");
3972           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3973                                                           TREE_TYPE (type1)));
3974         }
3975       else
3976         {
3977           if (!objc_ok)
3978             pedwarn (colon_loc, 0,
3979                      "pointer type mismatch in conditional expression");
3980           result_type = build_pointer_type (void_type_node);
3981         }
3982     }
3983   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3984     {
3985       if (!null_pointer_constant_p (orig_op2))
3986         pedwarn (colon_loc, 0,
3987                  "pointer/integer type mismatch in conditional expression");
3988       else
3989         {
3990           op2 = null_pointer_node;
3991         }
3992       result_type = type1;
3993     }
3994   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3995     {
3996       if (!null_pointer_constant_p (orig_op1))
3997         pedwarn (colon_loc, 0,
3998                  "pointer/integer type mismatch in conditional expression");
3999       else
4000         {
4001           op1 = null_pointer_node;
4002         }
4003       result_type = type2;
4004     }
4005
4006   if (!result_type)
4007     {
4008       if (flag_cond_mismatch)
4009         result_type = void_type_node;
4010       else
4011         {
4012           error_at (colon_loc, "type mismatch in conditional expression");
4013           return error_mark_node;
4014         }
4015     }
4016
4017   /* Merge const and volatile flags of the incoming types.  */
4018   result_type
4019     = build_type_variant (result_type,
4020                           TREE_READONLY (op1) || TREE_READONLY (op2),
4021                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
4022
4023   if (result_type != TREE_TYPE (op1))
4024     op1 = convert_and_check (result_type, op1);
4025   if (result_type != TREE_TYPE (op2))
4026     op2 = convert_and_check (result_type, op2);
4027
4028   if (ifexp_bcp && ifexp == truthvalue_true_node)
4029     {
4030       op2_int_operands = true;
4031       op1 = c_fully_fold (op1, require_constant_value, NULL);
4032     }
4033   if (ifexp_bcp && ifexp == truthvalue_false_node)
4034     {
4035       op1_int_operands = true;
4036       op2 = c_fully_fold (op2, require_constant_value, NULL);
4037     }
4038   int_const = int_operands = (ifexp_int_operands
4039                               && op1_int_operands
4040                               && op2_int_operands);
4041   if (int_operands)
4042     {
4043       int_const = ((ifexp == truthvalue_true_node
4044                     && TREE_CODE (orig_op1) == INTEGER_CST
4045                     && !TREE_OVERFLOW (orig_op1))
4046                    || (ifexp == truthvalue_false_node
4047                        && TREE_CODE (orig_op2) == INTEGER_CST
4048                        && !TREE_OVERFLOW (orig_op2)));
4049     }
4050   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
4051     ret = fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
4052   else
4053     {
4054       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
4055       if (int_operands)
4056         ret = note_integer_operands (ret);
4057     }
4058   if (ep_result_type)
4059     ret = build1 (EXCESS_PRECISION_EXPR, ep_result_type, ret);
4060
4061   protected_set_expr_location (ret, colon_loc);
4062   return ret;
4063 }
4064 \f
4065 /* Return a compound expression that performs two expressions and
4066    returns the value of the second of them.
4067
4068    LOC is the location of the COMPOUND_EXPR.  */
4069
4070 tree
4071 build_compound_expr (location_t loc, tree expr1, tree expr2)
4072 {
4073   bool expr1_int_operands, expr2_int_operands;
4074   tree eptype = NULL_TREE;
4075   tree ret;
4076
4077   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4078   if (expr1_int_operands)
4079     expr1 = remove_c_maybe_const_expr (expr1);
4080   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4081   if (expr2_int_operands)
4082     expr2 = remove_c_maybe_const_expr (expr2);
4083
4084   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4085     expr1 = TREE_OPERAND (expr1, 0);
4086   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4087     {
4088       eptype = TREE_TYPE (expr2);
4089       expr2 = TREE_OPERAND (expr2, 0);
4090     }
4091
4092   if (!TREE_SIDE_EFFECTS (expr1))
4093     {
4094       /* The left-hand operand of a comma expression is like an expression
4095          statement: with -Wunused, we should warn if it doesn't have
4096          any side-effects, unless it was explicitly cast to (void).  */
4097       if (warn_unused_value)
4098         {
4099           if (VOID_TYPE_P (TREE_TYPE (expr1))
4100               && CONVERT_EXPR_P (expr1))
4101             ; /* (void) a, b */
4102           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4103                    && TREE_CODE (expr1) == COMPOUND_EXPR
4104                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4105             ; /* (void) a, (void) b, c */
4106           else
4107             warning_at (loc, OPT_Wunused_value,
4108                         "left-hand operand of comma expression has no effect");
4109         }
4110     }
4111
4112   /* With -Wunused, we should also warn if the left-hand operand does have
4113      side-effects, but computes a value which is not used.  For example, in
4114      `foo() + bar(), baz()' the result of the `+' operator is not used,
4115      so we should issue a warning.  */
4116   else if (warn_unused_value)
4117     warn_if_unused_value (expr1, loc);
4118
4119   if (expr2 == error_mark_node)
4120     return error_mark_node;
4121
4122   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4123
4124   if (flag_isoc99
4125       && expr1_int_operands
4126       && expr2_int_operands)
4127     ret = note_integer_operands (ret);
4128
4129   if (eptype)
4130     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4131
4132   protected_set_expr_location (ret, loc);
4133   return ret;
4134 }
4135
4136 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4137    which we are casting.  OTYPE is the type of the expression being
4138    cast.  Both TYPE and OTYPE are pointer types.  -Wcast-qual appeared
4139    on the command line.  */
4140
4141 static void
4142 handle_warn_cast_qual (tree type, tree otype)
4143 {
4144   tree in_type = type;
4145   tree in_otype = otype;
4146   int added = 0;
4147   int discarded = 0;
4148   bool is_const;
4149
4150   /* Check that the qualifiers on IN_TYPE are a superset of the
4151      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4152      nodes is uninteresting and we stop as soon as we hit a
4153      non-POINTER_TYPE node on either type.  */
4154   do
4155     {
4156       in_otype = TREE_TYPE (in_otype);
4157       in_type = TREE_TYPE (in_type);
4158
4159       /* GNU C allows cv-qualified function types.  'const' means the
4160          function is very pure, 'volatile' means it can't return.  We
4161          need to warn when such qualifiers are added, not when they're
4162          taken away.  */
4163       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4164           && TREE_CODE (in_type) == FUNCTION_TYPE)
4165         added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
4166       else
4167         discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
4168     }
4169   while (TREE_CODE (in_type) == POINTER_TYPE
4170          && TREE_CODE (in_otype) == POINTER_TYPE);
4171
4172   if (added)
4173     warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
4174
4175   if (discarded)
4176     /* There are qualifiers present in IN_OTYPE that are not present
4177        in IN_TYPE.  */
4178     warning (OPT_Wcast_qual,
4179              "cast discards qualifiers from pointer target type");
4180
4181   if (added || discarded)
4182     return;
4183
4184   /* A cast from **T to const **T is unsafe, because it can cause a
4185      const value to be changed with no additional warning.  We only
4186      issue this warning if T is the same on both sides, and we only
4187      issue the warning if there are the same number of pointers on
4188      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4189      cast is unsafe when a qualifier is added at one level and const
4190      is not present at all outer levels.
4191
4192      To issue this warning, we check at each level whether the cast
4193      adds new qualifiers not already seen.  We don't need to special
4194      case function types, as they won't have the same
4195      TYPE_MAIN_VARIANT.  */
4196
4197   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4198     return;
4199   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4200     return;
4201
4202   in_type = type;
4203   in_otype = otype;
4204   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4205   do
4206     {
4207       in_type = TREE_TYPE (in_type);
4208       in_otype = TREE_TYPE (in_otype);
4209       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4210           && !is_const)
4211         {
4212           warning (OPT_Wcast_qual,
4213                    ("new qualifiers in middle of multi-level non-const cast "
4214                     "are unsafe"));
4215           break;
4216         }
4217       if (is_const)
4218         is_const = TYPE_READONLY (in_type);
4219     }
4220   while (TREE_CODE (in_type) == POINTER_TYPE);
4221 }
4222
4223 /* Build an expression representing a cast to type TYPE of expression EXPR.
4224    LOC is the location of the cast-- typically the open paren of the cast.  */
4225
4226 tree
4227 build_c_cast (location_t loc, tree type, tree expr)
4228 {
4229   tree value;
4230
4231   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4232     expr = TREE_OPERAND (expr, 0);
4233
4234   value = expr;
4235
4236   if (type == error_mark_node || expr == error_mark_node)
4237     return error_mark_node;
4238
4239   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4240      only in <protocol> qualifications.  But when constructing cast expressions,
4241      the protocols do matter and must be kept around.  */
4242   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4243     return build1 (NOP_EXPR, type, expr);
4244
4245   type = TYPE_MAIN_VARIANT (type);
4246
4247   if (TREE_CODE (type) == ARRAY_TYPE)
4248     {
4249       error_at (loc, "cast specifies array type");
4250       return error_mark_node;
4251     }
4252
4253   if (TREE_CODE (type) == FUNCTION_TYPE)
4254     {
4255       error_at (loc, "cast specifies function type");
4256       return error_mark_node;
4257     }
4258
4259   if (!VOID_TYPE_P (type))
4260     {
4261       value = require_complete_type (value);
4262       if (value == error_mark_node)
4263         return error_mark_node;
4264     }
4265
4266   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4267     {
4268       if (TREE_CODE (type) == RECORD_TYPE
4269           || TREE_CODE (type) == UNION_TYPE)
4270         pedwarn (loc, OPT_pedantic,
4271                  "ISO C forbids casting nonscalar to the same type");
4272     }
4273   else if (TREE_CODE (type) == UNION_TYPE)
4274     {
4275       tree field;
4276
4277       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4278         if (TREE_TYPE (field) != error_mark_node
4279             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4280                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4281           break;
4282
4283       if (field)
4284         {
4285           tree t;
4286
4287           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4288           t = digest_init (loc, type,
4289                            build_constructor_single (type, field, value),
4290                            NULL_TREE, false, true, 0);
4291           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4292           return t;
4293         }
4294       error_at (loc, "cast to union type from type not present in union");
4295       return error_mark_node;
4296     }
4297   else
4298     {
4299       tree otype, ovalue;
4300
4301       if (type == void_type_node)
4302         {
4303           tree t = build1 (CONVERT_EXPR, type, value);
4304           SET_EXPR_LOCATION (t, loc);
4305           return t;
4306         }
4307
4308       otype = TREE_TYPE (value);
4309
4310       /* Optionally warn about potentially worrisome casts.  */
4311       if (warn_cast_qual
4312           && TREE_CODE (type) == POINTER_TYPE
4313           && TREE_CODE (otype) == POINTER_TYPE)
4314         handle_warn_cast_qual (type, otype);
4315
4316       /* Warn about possible alignment problems.  */
4317       if (STRICT_ALIGNMENT
4318           && TREE_CODE (type) == POINTER_TYPE
4319           && TREE_CODE (otype) == POINTER_TYPE
4320           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4321           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4322           /* Don't warn about opaque types, where the actual alignment
4323              restriction is unknown.  */
4324           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4325                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4326                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4327           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4328         warning_at (loc, OPT_Wcast_align,
4329                     "cast increases required alignment of target type");
4330
4331       if (TREE_CODE (type) == INTEGER_TYPE
4332           && TREE_CODE (otype) == POINTER_TYPE
4333           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4334       /* Unlike conversion of integers to pointers, where the
4335          warning is disabled for converting constants because
4336          of cases such as SIG_*, warn about converting constant
4337          pointers to integers. In some cases it may cause unwanted
4338          sign extension, and a warning is appropriate.  */
4339         warning_at (loc, OPT_Wpointer_to_int_cast,
4340                     "cast from pointer to integer of different size");
4341
4342       if (TREE_CODE (value) == CALL_EXPR
4343           && TREE_CODE (type) != TREE_CODE (otype))
4344         warning_at (loc, OPT_Wbad_function_cast,
4345                     "cast from function call of type %qT "
4346                     "to non-matching type %qT", otype, type);
4347
4348       if (TREE_CODE (type) == POINTER_TYPE
4349           && TREE_CODE (otype) == INTEGER_TYPE
4350           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4351           /* Don't warn about converting any constant.  */
4352           && !TREE_CONSTANT (value))
4353         warning_at (loc,
4354                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4355                     "of different size");
4356
4357       if (warn_strict_aliasing <= 2)
4358         strict_aliasing_warning (otype, type, expr);
4359
4360       /* If pedantic, warn for conversions between function and object
4361          pointer types, except for converting a null pointer constant
4362          to function pointer type.  */
4363       if (pedantic
4364           && TREE_CODE (type) == POINTER_TYPE
4365           && TREE_CODE (otype) == POINTER_TYPE
4366           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4367           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4368         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4369                  "conversion of function pointer to object pointer type");
4370
4371       if (pedantic
4372           && TREE_CODE (type) == POINTER_TYPE
4373           && TREE_CODE (otype) == POINTER_TYPE
4374           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4375           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4376           && !null_pointer_constant_p (value))
4377         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4378                  "conversion of object pointer to function pointer type");
4379
4380       ovalue = value;
4381       value = convert (type, value);
4382
4383       /* Ignore any integer overflow caused by the cast.  */
4384       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4385         {
4386           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4387             {
4388               if (!TREE_OVERFLOW (value))
4389                 {
4390                   /* Avoid clobbering a shared constant.  */
4391                   value = copy_node (value);
4392                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4393                 }
4394             }
4395           else if (TREE_OVERFLOW (value))
4396             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4397             value = build_int_cst_wide (TREE_TYPE (value),
4398                                         TREE_INT_CST_LOW (value),
4399                                         TREE_INT_CST_HIGH (value));
4400         }
4401     }
4402
4403   /* Don't let a cast be an lvalue.  */
4404   if (value == expr)
4405     value = non_lvalue (value);
4406
4407   /* Don't allow the results of casting to floating-point or complex
4408      types be confused with actual constants, or casts involving
4409      integer and pointer types other than direct integer-to-integer
4410      and integer-to-pointer be confused with integer constant
4411      expressions and null pointer constants.  */
4412   if (TREE_CODE (value) == REAL_CST
4413       || TREE_CODE (value) == COMPLEX_CST
4414       || (TREE_CODE (value) == INTEGER_CST
4415           && !((TREE_CODE (expr) == INTEGER_CST
4416                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4417                || TREE_CODE (expr) == REAL_CST
4418                || TREE_CODE (expr) == COMPLEX_CST)))
4419       value = build1 (NOP_EXPR, type, value);
4420
4421   if (CAN_HAVE_LOCATION_P (value))
4422     SET_EXPR_LOCATION (value, loc);
4423   return value;
4424 }
4425
4426 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4427    location of the open paren of the cast, or the position of the cast
4428    expr.  */
4429 tree
4430 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4431 {
4432   tree type;
4433   tree type_expr = NULL_TREE;
4434   bool type_expr_const = true;
4435   tree ret;
4436   int saved_wsp = warn_strict_prototypes;
4437
4438   /* This avoids warnings about unprototyped casts on
4439      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4440   if (TREE_CODE (expr) == INTEGER_CST)
4441     warn_strict_prototypes = 0;
4442   type = groktypename (type_name, &type_expr, &type_expr_const);
4443   warn_strict_prototypes = saved_wsp;
4444
4445   ret = build_c_cast (loc, type, expr);
4446   if (type_expr)
4447     {
4448       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4449       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4450       SET_EXPR_LOCATION (ret, loc);
4451     }
4452
4453   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4454     SET_EXPR_LOCATION (ret, loc);
4455
4456   /* C++ does not permits types to be defined in a cast.  */
4457   if (warn_cxx_compat && type_name->specs->tag_defined_p)
4458     warning_at (loc, OPT_Wc___compat,
4459                 "defining a type in a cast is invalid in C++");
4460
4461   return ret;
4462 }
4463 \f
4464 /* Build an assignment expression of lvalue LHS from value RHS.
4465    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4466    may differ from TREE_TYPE (LHS) for an enum bitfield.
4467    MODIFYCODE is the code for a binary operator that we use
4468    to combine the old value of LHS with RHS to get the new value.
4469    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4470    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4471    which may differ from TREE_TYPE (RHS) for an enum value.
4472
4473    LOCATION is the location of the MODIFYCODE operator.
4474    RHS_LOC is the location of the RHS.  */
4475
4476 tree
4477 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4478                    enum tree_code modifycode,
4479                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4480 {
4481   tree result;
4482   tree newrhs;
4483   tree rhs_semantic_type = NULL_TREE;
4484   tree lhstype = TREE_TYPE (lhs);
4485   tree olhstype = lhstype;
4486   bool npc;
4487
4488   /* Types that aren't fully specified cannot be used in assignments.  */
4489   lhs = require_complete_type (lhs);
4490
4491   /* Avoid duplicate error messages from operands that had errors.  */
4492   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4493     return error_mark_node;
4494
4495   if (!lvalue_or_else (lhs, lv_assign))
4496     return error_mark_node;
4497
4498   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4499     {
4500       rhs_semantic_type = TREE_TYPE (rhs);
4501       rhs = TREE_OPERAND (rhs, 0);
4502     }
4503
4504   newrhs = rhs;
4505
4506   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4507     {
4508       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4509                                       lhs_origtype, modifycode, rhs_loc, rhs,
4510                                       rhs_origtype);
4511       if (inner == error_mark_node)
4512         return error_mark_node;
4513       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4514                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4515       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4516       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4517       protected_set_expr_location (result, location);
4518       return result;
4519     }
4520
4521   /* If a binary op has been requested, combine the old LHS value with the RHS
4522      producing the value we should actually store into the LHS.  */
4523
4524   if (modifycode != NOP_EXPR)
4525     {
4526       lhs = c_fully_fold (lhs, false, NULL);
4527       lhs = stabilize_reference (lhs);
4528       newrhs = build_binary_op (location,
4529                                 modifycode, lhs, rhs, 1);
4530
4531       /* The original type of the right hand side is no longer
4532          meaningful.  */
4533       rhs_origtype = NULL_TREE;
4534     }
4535
4536   /* Give an error for storing in something that is 'const'.  */
4537
4538   if (TYPE_READONLY (lhstype)
4539       || ((TREE_CODE (lhstype) == RECORD_TYPE
4540            || TREE_CODE (lhstype) == UNION_TYPE)
4541           && C_TYPE_FIELDS_READONLY (lhstype)))
4542     {
4543       readonly_error (lhs, lv_assign);
4544       return error_mark_node;
4545     }
4546   else if (TREE_READONLY (lhs))
4547     readonly_warning (lhs, lv_assign);
4548
4549   /* If storing into a structure or union member,
4550      it has probably been given type `int'.
4551      Compute the type that would go with
4552      the actual amount of storage the member occupies.  */
4553
4554   if (TREE_CODE (lhs) == COMPONENT_REF
4555       && (TREE_CODE (lhstype) == INTEGER_TYPE
4556           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4557           || TREE_CODE (lhstype) == REAL_TYPE
4558           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4559     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4560
4561   /* If storing in a field that is in actuality a short or narrower than one,
4562      we must store in the field in its actual type.  */
4563
4564   if (lhstype != TREE_TYPE (lhs))
4565     {
4566       lhs = copy_node (lhs);
4567       TREE_TYPE (lhs) = lhstype;
4568     }
4569
4570   /* Issue -Wc++-compat warnings about an assignment to an enum type
4571      when LHS does not have its original type.  This happens for,
4572      e.g., an enum bitfield in a struct.  */
4573   if (warn_cxx_compat
4574       && lhs_origtype != NULL_TREE
4575       && lhs_origtype != lhstype
4576       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4577     {
4578       tree checktype = (rhs_origtype != NULL_TREE
4579                         ? rhs_origtype
4580                         : TREE_TYPE (rhs));
4581       if (checktype != error_mark_node
4582           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4583         warning_at (location, OPT_Wc___compat,
4584                     "enum conversion in assignment is invalid in C++");
4585     }
4586
4587   /* Convert new value to destination type.  Fold it first, then
4588      restore any excess precision information, for the sake of
4589      conversion warnings.  */
4590
4591   npc = null_pointer_constant_p (newrhs);
4592   newrhs = c_fully_fold (newrhs, false, NULL);
4593   if (rhs_semantic_type)
4594     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4595   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4596                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4597   if (TREE_CODE (newrhs) == ERROR_MARK)
4598     return error_mark_node;
4599
4600   /* Emit ObjC write barrier, if necessary.  */
4601   if (c_dialect_objc () && flag_objc_gc)
4602     {
4603       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4604       if (result)
4605         {
4606           protected_set_expr_location (result, location);
4607           return result;
4608         }
4609     }
4610
4611   /* Scan operands.  */
4612
4613   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4614   TREE_SIDE_EFFECTS (result) = 1;
4615   protected_set_expr_location (result, location);
4616
4617   /* If we got the LHS in a different type for storing in,
4618      convert the result back to the nominal type of LHS
4619      so that the value we return always has the same type
4620      as the LHS argument.  */
4621
4622   if (olhstype == TREE_TYPE (result))
4623     return result;
4624
4625   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
4626                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
4627   protected_set_expr_location (result, location);
4628   return result;
4629 }
4630 \f
4631 /* Convert value RHS to type TYPE as preparation for an assignment to
4632    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
4633    original type of RHS; this differs from TREE_TYPE (RHS) for enum
4634    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
4635    constant before any folding.
4636    The real work of conversion is done by `convert'.
4637    The purpose of this function is to generate error messages
4638    for assignments that are not allowed in C.
4639    ERRTYPE says whether it is argument passing, assignment,
4640    initialization or return.
4641
4642    LOCATION is the location of the RHS.
4643    FUNCTION is a tree for the function being called.
4644    PARMNUM is the number of the argument, for printing in error messages.  */
4645
4646 static tree
4647 convert_for_assignment (location_t location, tree type, tree rhs,
4648                         tree origtype, enum impl_conv errtype,
4649                         bool null_pointer_constant, tree fundecl,
4650                         tree function, int parmnum)
4651 {
4652   enum tree_code codel = TREE_CODE (type);
4653   tree orig_rhs = rhs;
4654   tree rhstype;
4655   enum tree_code coder;
4656   tree rname = NULL_TREE;
4657   bool objc_ok = false;
4658
4659   if (errtype == ic_argpass)
4660     {
4661       tree selector;
4662       /* Change pointer to function to the function itself for
4663          diagnostics.  */
4664       if (TREE_CODE (function) == ADDR_EXPR
4665           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4666         function = TREE_OPERAND (function, 0);
4667
4668       /* Handle an ObjC selector specially for diagnostics.  */
4669       selector = objc_message_selector ();
4670       rname = function;
4671       if (selector && parmnum > 2)
4672         {
4673           rname = selector;
4674           parmnum -= 2;
4675         }
4676     }
4677
4678   /* This macro is used to emit diagnostics to ensure that all format
4679      strings are complete sentences, visible to gettext and checked at
4680      compile time.  */
4681 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4682   do {                                                                   \
4683     switch (errtype)                                                     \
4684       {                                                                  \
4685       case ic_argpass:                                                   \
4686         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4687           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4688                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4689                   "expected %qT but argument is of type %qT",            \
4690                   type, rhstype);                                        \
4691         break;                                                           \
4692       case ic_assign:                                                    \
4693         pedwarn (LOCATION, OPT, AS);                                     \
4694         break;                                                           \
4695       case ic_init:                                                      \
4696         pedwarn (LOCATION, OPT, IN);                                     \
4697         break;                                                           \
4698       case ic_return:                                                    \
4699         pedwarn (LOCATION, OPT, RE);                                     \
4700         break;                                                           \
4701       default:                                                           \
4702         gcc_unreachable ();                                              \
4703       }                                                                  \
4704   } while (0)
4705
4706   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4707     rhs = TREE_OPERAND (rhs, 0);
4708
4709   rhstype = TREE_TYPE (rhs);
4710   coder = TREE_CODE (rhstype);
4711
4712   if (coder == ERROR_MARK)
4713     return error_mark_node;
4714
4715   if (c_dialect_objc ())
4716     {
4717       int parmno;
4718
4719       switch (errtype)
4720         {
4721         case ic_return:
4722           parmno = 0;
4723           break;
4724
4725         case ic_assign:
4726           parmno = -1;
4727           break;
4728
4729         case ic_init:
4730           parmno = -2;
4731           break;
4732
4733         default:
4734           parmno = parmnum;
4735           break;
4736         }
4737
4738       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4739     }
4740
4741   if (warn_cxx_compat)
4742     {
4743       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
4744       if (checktype != error_mark_node
4745           && TREE_CODE (type) == ENUMERAL_TYPE
4746           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
4747         {
4748           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
4749                                G_("enum conversion when passing argument "
4750                                   "%d of %qE is invalid in C++"),
4751                                G_("enum conversion in assignment is "
4752                                   "invalid in C++"),
4753                                G_("enum conversion in initialization is "
4754                                   "invalid in C++"),
4755                                G_("enum conversion in return is "
4756                                   "invalid in C++"));
4757         }
4758     }
4759
4760   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4761     return rhs;
4762
4763   if (coder == VOID_TYPE)
4764     {
4765       /* Except for passing an argument to an unprototyped function,
4766          this is a constraint violation.  When passing an argument to
4767          an unprototyped function, it is compile-time undefined;
4768          making it a constraint in that case was rejected in
4769          DR#252.  */
4770       error_at (location, "void value not ignored as it ought to be");
4771       return error_mark_node;
4772     }
4773   rhs = require_complete_type (rhs);
4774   if (rhs == error_mark_node)
4775     return error_mark_node;
4776   /* A type converts to a reference to it.
4777      This code doesn't fully support references, it's just for the
4778      special case of va_start and va_copy.  */
4779   if (codel == REFERENCE_TYPE
4780       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4781     {
4782       if (!lvalue_p (rhs))
4783         {
4784           error_at (location, "cannot pass rvalue to reference parameter");
4785           return error_mark_node;
4786         }
4787       if (!c_mark_addressable (rhs))
4788         return error_mark_node;
4789       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4790       SET_EXPR_LOCATION (rhs, location);
4791
4792       /* We already know that these two types are compatible, but they
4793          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4794          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4795          likely to be va_list, a typedef to __builtin_va_list, which
4796          is different enough that it will cause problems later.  */
4797       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4798         {
4799           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4800           SET_EXPR_LOCATION (rhs, location);
4801         }
4802
4803       rhs = build1 (NOP_EXPR, type, rhs);
4804       SET_EXPR_LOCATION (rhs, location);
4805       return rhs;
4806     }
4807   /* Some types can interconvert without explicit casts.  */
4808   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4809            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4810     return convert (type, rhs);
4811   /* Arithmetic types all interconvert, and enum is treated like int.  */
4812   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4813             || codel == FIXED_POINT_TYPE
4814             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4815             || codel == BOOLEAN_TYPE)
4816            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4817                || coder == FIXED_POINT_TYPE
4818                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4819                || coder == BOOLEAN_TYPE))
4820     {
4821       tree ret;
4822       bool save = in_late_binary_op;
4823       if (codel == BOOLEAN_TYPE)
4824         in_late_binary_op = true;
4825       ret = convert_and_check (type, orig_rhs);
4826       if (codel == BOOLEAN_TYPE)
4827         in_late_binary_op = save;
4828       return ret;
4829     }
4830
4831   /* Aggregates in different TUs might need conversion.  */
4832   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4833       && codel == coder
4834       && comptypes (type, rhstype))
4835     return convert_and_check (type, rhs);
4836
4837   /* Conversion to a transparent union from its member types.
4838      This applies only to function arguments.  */
4839   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4840       && errtype == ic_argpass)
4841     {
4842       tree memb, marginal_memb = NULL_TREE;
4843
4844       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4845         {
4846           tree memb_type = TREE_TYPE (memb);
4847
4848           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4849                          TYPE_MAIN_VARIANT (rhstype)))
4850             break;
4851
4852           if (TREE_CODE (memb_type) != POINTER_TYPE)
4853             continue;
4854
4855           if (coder == POINTER_TYPE)
4856             {
4857               tree ttl = TREE_TYPE (memb_type);
4858               tree ttr = TREE_TYPE (rhstype);
4859
4860               /* Any non-function converts to a [const][volatile] void *
4861                  and vice versa; otherwise, targets must be the same.
4862                  Meanwhile, the lhs target must have all the qualifiers of
4863                  the rhs.  */
4864               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4865                   || comp_target_types (location, memb_type, rhstype))
4866                 {
4867                   /* If this type won't generate any warnings, use it.  */
4868                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4869                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4870                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4871                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4872                              == TYPE_QUALS (ttr))
4873                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4874                              == TYPE_QUALS (ttl))))
4875                     break;
4876
4877                   /* Keep looking for a better type, but remember this one.  */
4878                   if (!marginal_memb)
4879                     marginal_memb = memb;
4880                 }
4881             }
4882
4883           /* Can convert integer zero to any pointer type.  */
4884           if (null_pointer_constant)
4885             {
4886               rhs = null_pointer_node;
4887               break;
4888             }
4889         }
4890
4891       if (memb || marginal_memb)
4892         {
4893           if (!memb)
4894             {
4895               /* We have only a marginally acceptable member type;
4896                  it needs a warning.  */
4897               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4898               tree ttr = TREE_TYPE (rhstype);
4899
4900               /* Const and volatile mean something different for function
4901                  types, so the usual warnings are not appropriate.  */
4902               if (TREE_CODE (ttr) == FUNCTION_TYPE
4903                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4904                 {
4905                   /* Because const and volatile on functions are
4906                      restrictions that say the function will not do
4907                      certain things, it is okay to use a const or volatile
4908                      function where an ordinary one is wanted, but not
4909                      vice-versa.  */
4910                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4911                     WARN_FOR_ASSIGNMENT (location, 0,
4912                                          G_("passing argument %d of %qE "
4913                                             "makes qualified function "
4914                                             "pointer from unqualified"),
4915                                          G_("assignment makes qualified "
4916                                             "function pointer from "
4917                                             "unqualified"),
4918                                          G_("initialization makes qualified "
4919                                             "function pointer from "
4920                                             "unqualified"),
4921                                          G_("return makes qualified function "
4922                                             "pointer from unqualified"));
4923                 }
4924               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4925                 WARN_FOR_ASSIGNMENT (location, 0,
4926                                      G_("passing argument %d of %qE discards "
4927                                         "qualifiers from pointer target type"),
4928                                      G_("assignment discards qualifiers "
4929                                         "from pointer target type"),
4930                                      G_("initialization discards qualifiers "
4931                                         "from pointer target type"),
4932                                      G_("return discards qualifiers from "
4933                                         "pointer target type"));
4934
4935               memb = marginal_memb;
4936             }
4937
4938           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4939             pedwarn (location, OPT_pedantic,
4940                      "ISO C prohibits argument conversion to union type");
4941
4942           rhs = fold_convert (TREE_TYPE (memb), rhs);
4943           return build_constructor_single (type, memb, rhs);
4944         }
4945     }
4946
4947   /* Conversions among pointers */
4948   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4949            && (coder == codel))
4950     {
4951       tree ttl = TREE_TYPE (type);
4952       tree ttr = TREE_TYPE (rhstype);
4953       tree mvl = ttl;
4954       tree mvr = ttr;
4955       bool is_opaque_pointer;
4956       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4957
4958       if (TREE_CODE (mvl) != ARRAY_TYPE)
4959         mvl = TYPE_MAIN_VARIANT (mvl);
4960       if (TREE_CODE (mvr) != ARRAY_TYPE)
4961         mvr = TYPE_MAIN_VARIANT (mvr);
4962       /* Opaque pointers are treated like void pointers.  */
4963       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4964
4965       /* C++ does not allow the implicit conversion void* -> T*.  However,
4966          for the purpose of reducing the number of false positives, we
4967          tolerate the special case of
4968
4969                 int *p = NULL;
4970
4971          where NULL is typically defined in C to be '(void *) 0'.  */
4972       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4973         warning_at (location, OPT_Wc___compat,
4974                     "request for implicit conversion "
4975                     "from %qT to %qT not permitted in C++", rhstype, type);
4976
4977       /* Check if the right-hand side has a format attribute but the
4978          left-hand side doesn't.  */
4979       if (warn_missing_format_attribute
4980           && check_missing_format_attribute (type, rhstype))
4981         {
4982           switch (errtype)
4983           {
4984           case ic_argpass:
4985             warning_at (location, OPT_Wmissing_format_attribute,
4986                         "argument %d of %qE might be "
4987                         "a candidate for a format attribute",
4988                         parmnum, rname);
4989             break;
4990           case ic_assign:
4991             warning_at (location, OPT_Wmissing_format_attribute,
4992                         "assignment left-hand side might be "
4993                         "a candidate for a format attribute");
4994             break;
4995           case ic_init:
4996             warning_at (location, OPT_Wmissing_format_attribute,
4997                         "initialization left-hand side might be "
4998                         "a candidate for a format attribute");
4999             break;
5000           case ic_return:
5001             warning_at (location, OPT_Wmissing_format_attribute,
5002                         "return type might be "
5003                         "a candidate for a format attribute");
5004             break;
5005           default:
5006             gcc_unreachable ();
5007           }
5008         }
5009
5010       /* Any non-function converts to a [const][volatile] void *
5011          and vice versa; otherwise, targets must be the same.
5012          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5013       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5014           || (target_cmp = comp_target_types (location, type, rhstype))
5015           || is_opaque_pointer
5016           || (c_common_unsigned_type (mvl)
5017               == c_common_unsigned_type (mvr)))
5018         {
5019           if (pedantic
5020               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5021                   ||
5022                   (VOID_TYPE_P (ttr)
5023                    && !null_pointer_constant
5024                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5025             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5026                                  G_("ISO C forbids passing argument %d of "
5027                                     "%qE between function pointer "
5028                                     "and %<void *%>"),
5029                                  G_("ISO C forbids assignment between "
5030                                     "function pointer and %<void *%>"),
5031                                  G_("ISO C forbids initialization between "
5032                                     "function pointer and %<void *%>"),
5033                                  G_("ISO C forbids return between function "
5034                                     "pointer and %<void *%>"));
5035           /* Const and volatile mean something different for function types,
5036              so the usual warnings are not appropriate.  */
5037           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5038                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5039             {
5040               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
5041                 {
5042                   /* Types differing only by the presence of the 'volatile'
5043                      qualifier are acceptable if the 'volatile' has been added
5044                      in by the Objective-C EH machinery.  */
5045                   if (!objc_type_quals_match (ttl, ttr))
5046                     WARN_FOR_ASSIGNMENT (location, 0,
5047                                          G_("passing argument %d of %qE discards "
5048                                             "qualifiers from pointer target type"),
5049                                          G_("assignment discards qualifiers "
5050                                             "from pointer target type"),
5051                                          G_("initialization discards qualifiers "
5052                                             "from pointer target type"),
5053                                          G_("return discards qualifiers from "
5054                                             "pointer target type"));
5055                 }
5056               /* If this is not a case of ignoring a mismatch in signedness,
5057                  no warning.  */
5058               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5059                        || target_cmp)
5060                 ;
5061               /* If there is a mismatch, do warn.  */
5062               else if (warn_pointer_sign)
5063                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5064                                      G_("pointer targets in passing argument "
5065                                         "%d of %qE differ in signedness"),
5066                                      G_("pointer targets in assignment "
5067                                         "differ in signedness"),
5068                                      G_("pointer targets in initialization "
5069                                         "differ in signedness"),
5070                                      G_("pointer targets in return differ "
5071                                         "in signedness"));
5072             }
5073           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5074                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5075             {
5076               /* Because const and volatile on functions are restrictions
5077                  that say the function will not do certain things,
5078                  it is okay to use a const or volatile function
5079                  where an ordinary one is wanted, but not vice-versa.  */
5080               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
5081                 WARN_FOR_ASSIGNMENT (location, 0,
5082                                      G_("passing argument %d of %qE makes "
5083                                         "qualified function pointer "
5084                                         "from unqualified"),
5085                                      G_("assignment makes qualified function "
5086                                         "pointer from unqualified"),
5087                                      G_("initialization makes qualified "
5088                                         "function pointer from unqualified"),
5089                                      G_("return makes qualified function "
5090                                         "pointer from unqualified"));
5091             }
5092         }
5093       else
5094         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5095         if (!objc_ok)
5096           WARN_FOR_ASSIGNMENT (location, 0,
5097                                G_("passing argument %d of %qE from "
5098                                   "incompatible pointer type"),
5099                                G_("assignment from incompatible pointer type"),
5100                                G_("initialization from incompatible "
5101                                   "pointer type"),
5102                                G_("return from incompatible pointer type"));
5103
5104       return convert (type, rhs);
5105     }
5106   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5107     {
5108       /* ??? This should not be an error when inlining calls to
5109          unprototyped functions.  */
5110       error_at (location, "invalid use of non-lvalue array");
5111       return error_mark_node;
5112     }
5113   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5114     {
5115       /* An explicit constant 0 can convert to a pointer,
5116          or one that results from arithmetic, even including
5117          a cast to integer type.  */
5118       if (!null_pointer_constant)
5119         WARN_FOR_ASSIGNMENT (location, 0,
5120                              G_("passing argument %d of %qE makes "
5121                                 "pointer from integer without a cast"),
5122                              G_("assignment makes pointer from integer "
5123                                 "without a cast"),
5124                              G_("initialization makes pointer from "
5125                                 "integer without a cast"),
5126                              G_("return makes pointer from integer "
5127                                 "without a cast"));
5128
5129       return convert (type, rhs);
5130     }
5131   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5132     {
5133       WARN_FOR_ASSIGNMENT (location, 0,
5134                            G_("passing argument %d of %qE makes integer "
5135                               "from pointer without a cast"),
5136                            G_("assignment makes integer from pointer "
5137                               "without a cast"),
5138                            G_("initialization makes integer from pointer "
5139                               "without a cast"),
5140                            G_("return makes integer from pointer "
5141                               "without a cast"));
5142       return convert (type, rhs);
5143     }
5144   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5145     {
5146       tree ret;
5147       bool save = in_late_binary_op;
5148       in_late_binary_op = true;
5149       ret = convert (type, rhs);
5150       in_late_binary_op = save;
5151       return ret;
5152     }
5153
5154   switch (errtype)
5155     {
5156     case ic_argpass:
5157       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5158       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5159               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5160               "expected %qT but argument is of type %qT", type, rhstype);
5161       break;
5162     case ic_assign:
5163       error_at (location, "incompatible types when assigning to type %qT from "
5164                 "type %qT", type, rhstype);
5165       break;
5166     case ic_init:
5167       error_at (location,
5168                 "incompatible types when initializing type %qT using type %qT",
5169                 type, rhstype);
5170       break;
5171     case ic_return:
5172       error_at (location,
5173                 "incompatible types when returning type %qT but %qT was "
5174                 "expected", rhstype, type);
5175       break;
5176     default:
5177       gcc_unreachable ();
5178     }
5179
5180   return error_mark_node;
5181 }
5182 \f
5183 /* If VALUE is a compound expr all of whose expressions are constant, then
5184    return its value.  Otherwise, return error_mark_node.
5185
5186    This is for handling COMPOUND_EXPRs as initializer elements
5187    which is allowed with a warning when -pedantic is specified.  */
5188
5189 static tree
5190 valid_compound_expr_initializer (tree value, tree endtype)
5191 {
5192   if (TREE_CODE (value) == COMPOUND_EXPR)
5193     {
5194       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5195           == error_mark_node)
5196         return error_mark_node;
5197       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5198                                               endtype);
5199     }
5200   else if (!initializer_constant_valid_p (value, endtype))
5201     return error_mark_node;
5202   else
5203     return value;
5204 }
5205 \f
5206 /* Perform appropriate conversions on the initial value of a variable,
5207    store it in the declaration DECL,
5208    and print any error messages that are appropriate.
5209    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5210    If the init is invalid, store an ERROR_MARK.
5211
5212    INIT_LOC is the location of the initial value.  */
5213
5214 void
5215 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5216 {
5217   tree value, type;
5218   bool npc = false;
5219
5220   /* If variable's type was invalidly declared, just ignore it.  */
5221
5222   type = TREE_TYPE (decl);
5223   if (TREE_CODE (type) == ERROR_MARK)
5224     return;
5225
5226   /* Digest the specified initializer into an expression.  */
5227
5228   if (init)
5229     npc = null_pointer_constant_p (init);
5230   value = digest_init (init_loc, type, init, origtype, npc,
5231                        true, TREE_STATIC (decl));
5232
5233   /* Store the expression if valid; else report error.  */
5234
5235   if (!in_system_header
5236       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5237     warning (OPT_Wtraditional, "traditional C rejects automatic "
5238              "aggregate initialization");
5239
5240   DECL_INITIAL (decl) = value;
5241
5242   /* ANSI wants warnings about out-of-range constant initializers.  */
5243   STRIP_TYPE_NOPS (value);
5244   if (TREE_STATIC (decl))
5245     constant_expression_warning (value);
5246
5247   /* Check if we need to set array size from compound literal size.  */
5248   if (TREE_CODE (type) == ARRAY_TYPE
5249       && TYPE_DOMAIN (type) == 0
5250       && value != error_mark_node)
5251     {
5252       tree inside_init = init;
5253
5254       STRIP_TYPE_NOPS (inside_init);
5255       inside_init = fold (inside_init);
5256
5257       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5258         {
5259           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5260
5261           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5262             {
5263               /* For int foo[] = (int [3]){1}; we need to set array size
5264                  now since later on array initializer will be just the
5265                  brace enclosed list of the compound literal.  */
5266               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5267               TREE_TYPE (decl) = type;
5268               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5269               layout_type (type);
5270               layout_decl (cldecl, 0);
5271             }
5272         }
5273     }
5274 }
5275 \f
5276 /* Methods for storing and printing names for error messages.  */
5277
5278 /* Implement a spelling stack that allows components of a name to be pushed
5279    and popped.  Each element on the stack is this structure.  */
5280
5281 struct spelling
5282 {
5283   int kind;
5284   union
5285     {
5286       unsigned HOST_WIDE_INT i;
5287       const char *s;
5288     } u;
5289 };
5290
5291 #define SPELLING_STRING 1
5292 #define SPELLING_MEMBER 2
5293 #define SPELLING_BOUNDS 3
5294
5295 static struct spelling *spelling;       /* Next stack element (unused).  */
5296 static struct spelling *spelling_base;  /* Spelling stack base.  */
5297 static int spelling_size;               /* Size of the spelling stack.  */
5298
5299 /* Macros to save and restore the spelling stack around push_... functions.
5300    Alternative to SAVE_SPELLING_STACK.  */
5301
5302 #define SPELLING_DEPTH() (spelling - spelling_base)
5303 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5304
5305 /* Push an element on the spelling stack with type KIND and assign VALUE
5306    to MEMBER.  */
5307
5308 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5309 {                                                                       \
5310   int depth = SPELLING_DEPTH ();                                        \
5311                                                                         \
5312   if (depth >= spelling_size)                                           \
5313     {                                                                   \
5314       spelling_size += 10;                                              \
5315       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5316                                   spelling_size);                       \
5317       RESTORE_SPELLING_DEPTH (depth);                                   \
5318     }                                                                   \
5319                                                                         \
5320   spelling->kind = (KIND);                                              \
5321   spelling->MEMBER = (VALUE);                                           \
5322   spelling++;                                                           \
5323 }
5324
5325 /* Push STRING on the stack.  Printed literally.  */
5326
5327 static void
5328 push_string (const char *string)
5329 {
5330   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5331 }
5332
5333 /* Push a member name on the stack.  Printed as '.' STRING.  */
5334
5335 static void
5336 push_member_name (tree decl)
5337 {
5338   const char *const string
5339     = (DECL_NAME (decl)
5340        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5341        : _("<anonymous>"));
5342   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5343 }
5344
5345 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5346
5347 static void
5348 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5349 {
5350   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5351 }
5352
5353 /* Compute the maximum size in bytes of the printed spelling.  */
5354
5355 static int
5356 spelling_length (void)
5357 {
5358   int size = 0;
5359   struct spelling *p;
5360
5361   for (p = spelling_base; p < spelling; p++)
5362     {
5363       if (p->kind == SPELLING_BOUNDS)
5364         size += 25;
5365       else
5366         size += strlen (p->u.s) + 1;
5367     }
5368
5369   return size;
5370 }
5371
5372 /* Print the spelling to BUFFER and return it.  */
5373
5374 static char *
5375 print_spelling (char *buffer)
5376 {
5377   char *d = buffer;
5378   struct spelling *p;
5379
5380   for (p = spelling_base; p < spelling; p++)
5381     if (p->kind == SPELLING_BOUNDS)
5382       {
5383         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5384         d += strlen (d);
5385       }
5386     else
5387       {
5388         const char *s;
5389         if (p->kind == SPELLING_MEMBER)
5390           *d++ = '.';
5391         for (s = p->u.s; (*d = *s++); d++)
5392           ;
5393       }
5394   *d++ = '\0';
5395   return buffer;
5396 }
5397
5398 /* Issue an error message for a bad initializer component.
5399    MSGID identifies the message.
5400    The component name is taken from the spelling stack.  */
5401
5402 void
5403 error_init (const char *msgid)
5404 {
5405   char *ofwhat;
5406
5407   error ("%s", _(msgid));
5408   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5409   if (*ofwhat)
5410     error ("(near initialization for %qs)", ofwhat);
5411 }
5412
5413 /* Issue a pedantic warning for a bad initializer component.  OPT is
5414    the option OPT_* (from options.h) controlling this warning or 0 if
5415    it is unconditionally given.  MSGID identifies the message.  The
5416    component name is taken from the spelling stack.  */
5417
5418 void
5419 pedwarn_init (location_t location, int opt, const char *msgid)
5420 {
5421   char *ofwhat;
5422
5423   pedwarn (location, opt, "%s", _(msgid));
5424   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5425   if (*ofwhat)
5426     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5427 }
5428
5429 /* Issue a warning for a bad initializer component.
5430
5431    OPT is the OPT_W* value corresponding to the warning option that
5432    controls this warning.  MSGID identifies the message.  The
5433    component name is taken from the spelling stack.  */
5434
5435 static void
5436 warning_init (int opt, const char *msgid)
5437 {
5438   char *ofwhat;
5439
5440   warning (opt, "%s", _(msgid));
5441   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5442   if (*ofwhat)
5443     warning (opt, "(near initialization for %qs)", ofwhat);
5444 }
5445 \f
5446 /* If TYPE is an array type and EXPR is a parenthesized string
5447    constant, warn if pedantic that EXPR is being used to initialize an
5448    object of type TYPE.  */
5449
5450 void
5451 maybe_warn_string_init (tree type, struct c_expr expr)
5452 {
5453   if (pedantic
5454       && TREE_CODE (type) == ARRAY_TYPE
5455       && TREE_CODE (expr.value) == STRING_CST
5456       && expr.original_code != STRING_CST)
5457     pedwarn_init (input_location, OPT_pedantic,
5458                   "array initialized from parenthesized string constant");
5459 }
5460
5461 /* Digest the parser output INIT as an initializer for type TYPE.
5462    Return a C expression of type TYPE to represent the initial value.
5463
5464    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5465
5466    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5467
5468    If INIT is a string constant, STRICT_STRING is true if it is
5469    unparenthesized or we should not warn here for it being parenthesized.
5470    For other types of INIT, STRICT_STRING is not used.
5471
5472    INIT_LOC is the location of the INIT.
5473
5474    REQUIRE_CONSTANT requests an error if non-constant initializers or
5475    elements are seen.  */
5476
5477 static tree
5478 digest_init (location_t init_loc, tree type, tree init, tree origtype,
5479              bool null_pointer_constant, bool strict_string,
5480              int require_constant)
5481 {
5482   enum tree_code code = TREE_CODE (type);
5483   tree inside_init = init;
5484   tree semantic_type = NULL_TREE;
5485   bool maybe_const = true;
5486
5487   if (type == error_mark_node
5488       || !init
5489       || init == error_mark_node
5490       || TREE_TYPE (init) == error_mark_node)
5491     return error_mark_node;
5492
5493   STRIP_TYPE_NOPS (inside_init);
5494
5495   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5496     {
5497       semantic_type = TREE_TYPE (inside_init);
5498       inside_init = TREE_OPERAND (inside_init, 0);
5499     }
5500   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5501   inside_init = decl_constant_value_for_optimization (inside_init);
5502
5503   /* Initialization of an array of chars from a string constant
5504      optionally enclosed in braces.  */
5505
5506   if (code == ARRAY_TYPE && inside_init
5507       && TREE_CODE (inside_init) == STRING_CST)
5508     {
5509       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5510       /* Note that an array could be both an array of character type
5511          and an array of wchar_t if wchar_t is signed char or unsigned
5512          char.  */
5513       bool char_array = (typ1 == char_type_node
5514                          || typ1 == signed_char_type_node
5515                          || typ1 == unsigned_char_type_node);
5516       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5517       bool char16_array = !!comptypes (typ1, char16_type_node);
5518       bool char32_array = !!comptypes (typ1, char32_type_node);
5519
5520       if (char_array || wchar_array || char16_array || char32_array)
5521         {
5522           struct c_expr expr;
5523           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5524           expr.value = inside_init;
5525           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5526           expr.original_type = NULL;
5527           maybe_warn_string_init (type, expr);
5528
5529           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
5530             pedwarn_init (init_loc, OPT_pedantic,
5531                           "initialization of a flexible array member");
5532
5533           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5534                          TYPE_MAIN_VARIANT (type)))
5535             return inside_init;
5536
5537           if (char_array)
5538             {
5539               if (typ2 != char_type_node)
5540                 {
5541                   error_init ("char-array initialized from wide string");
5542                   return error_mark_node;
5543                 }
5544             }
5545           else
5546             {
5547               if (typ2 == char_type_node)
5548                 {
5549                   error_init ("wide character array initialized from non-wide "
5550                               "string");
5551                   return error_mark_node;
5552                 }
5553               else if (!comptypes(typ1, typ2))
5554                 {
5555                   error_init ("wide character array initialized from "
5556                               "incompatible wide string");
5557                   return error_mark_node;
5558                 }
5559             }
5560
5561           TREE_TYPE (inside_init) = type;
5562           if (TYPE_DOMAIN (type) != 0
5563               && TYPE_SIZE (type) != 0
5564               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
5565             {
5566               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
5567
5568               /* Subtract the size of a single (possibly wide) character
5569                  because it's ok to ignore the terminating null char
5570                  that is counted in the length of the constant.  */
5571               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5572                                         (len
5573                                          - (TYPE_PRECISION (typ1)
5574                                             / BITS_PER_UNIT))))
5575                 pedwarn_init (init_loc, 0,
5576                               ("initializer-string for array of chars "
5577                                "is too long"));
5578               else if (warn_cxx_compat
5579                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
5580                 warning_at (init_loc, OPT_Wc___compat,
5581                             ("initializer-string for array chars "
5582                              "is too long for C++"));
5583             }
5584
5585           return inside_init;
5586         }
5587       else if (INTEGRAL_TYPE_P (typ1))
5588         {
5589           error_init ("array of inappropriate type initialized "
5590                       "from string constant");
5591           return error_mark_node;
5592         }
5593     }
5594
5595   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5596      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5597      below and handle as a constructor.  */
5598   if (code == VECTOR_TYPE
5599       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5600       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5601       && TREE_CONSTANT (inside_init))
5602     {
5603       if (TREE_CODE (inside_init) == VECTOR_CST
5604           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5605                         TYPE_MAIN_VARIANT (type)))
5606         return inside_init;
5607
5608       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5609         {
5610           unsigned HOST_WIDE_INT ix;
5611           tree value;
5612           bool constant_p = true;
5613
5614           /* Iterate through elements and check if all constructor
5615              elements are *_CSTs.  */
5616           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5617             if (!CONSTANT_CLASS_P (value))
5618               {
5619                 constant_p = false;
5620                 break;
5621               }
5622
5623           if (constant_p)
5624             return build_vector_from_ctor (type,
5625                                            CONSTRUCTOR_ELTS (inside_init));
5626         }
5627     }
5628
5629   if (warn_sequence_point)
5630     verify_sequence_points (inside_init);
5631
5632   /* Any type can be initialized
5633      from an expression of the same type, optionally with braces.  */
5634
5635   if (inside_init && TREE_TYPE (inside_init) != 0
5636       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5637                      TYPE_MAIN_VARIANT (type))
5638           || (code == ARRAY_TYPE
5639               && comptypes (TREE_TYPE (inside_init), type))
5640           || (code == VECTOR_TYPE
5641               && comptypes (TREE_TYPE (inside_init), type))
5642           || (code == POINTER_TYPE
5643               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5644               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5645                             TREE_TYPE (type)))))
5646     {
5647       if (code == POINTER_TYPE)
5648         {
5649           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5650             {
5651               if (TREE_CODE (inside_init) == STRING_CST
5652                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5653                 inside_init = array_to_pointer_conversion
5654                   (init_loc, inside_init);
5655               else
5656                 {
5657                   error_init ("invalid use of non-lvalue array");
5658                   return error_mark_node;
5659                 }
5660             }
5661         }
5662
5663       if (code == VECTOR_TYPE)
5664         /* Although the types are compatible, we may require a
5665            conversion.  */
5666         inside_init = convert (type, inside_init);
5667
5668       if (require_constant
5669           && (code == VECTOR_TYPE || !flag_isoc99)
5670           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5671         {
5672           /* As an extension, allow initializing objects with static storage
5673              duration with compound literals (which are then treated just as
5674              the brace enclosed list they contain).  Also allow this for
5675              vectors, as we can only assign them with compound literals.  */
5676           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5677           inside_init = DECL_INITIAL (decl);
5678         }
5679
5680       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5681           && TREE_CODE (inside_init) != CONSTRUCTOR)
5682         {
5683           error_init ("array initialized from non-constant array expression");
5684           return error_mark_node;
5685         }
5686
5687       /* Compound expressions can only occur here if -pedantic or
5688          -pedantic-errors is specified.  In the later case, we always want
5689          an error.  In the former case, we simply want a warning.  */
5690       if (require_constant && pedantic
5691           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5692         {
5693           inside_init
5694             = valid_compound_expr_initializer (inside_init,
5695                                                TREE_TYPE (inside_init));
5696           if (inside_init == error_mark_node)
5697             error_init ("initializer element is not constant");
5698           else
5699             pedwarn_init (init_loc, OPT_pedantic,
5700                           "initializer element is not constant");
5701           if (flag_pedantic_errors)
5702             inside_init = error_mark_node;
5703         }
5704       else if (require_constant
5705                && !initializer_constant_valid_p (inside_init,
5706                                                  TREE_TYPE (inside_init)))
5707         {
5708           error_init ("initializer element is not constant");
5709           inside_init = error_mark_node;
5710         }
5711       else if (require_constant && !maybe_const)
5712         pedwarn_init (init_loc, 0,
5713                       "initializer element is not a constant expression");
5714
5715       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5716       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5717         inside_init = convert_for_assignment (init_loc, type, inside_init,
5718                                               origtype,
5719                                               ic_init, null_pointer_constant,
5720                                               NULL_TREE, NULL_TREE, 0);
5721       return inside_init;
5722     }
5723
5724   /* Handle scalar types, including conversions.  */
5725
5726   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5727       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5728       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5729     {
5730       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5731           && (TREE_CODE (init) == STRING_CST
5732               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5733         inside_init = init = array_to_pointer_conversion (init_loc, init);
5734       if (semantic_type)
5735         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5736                               inside_init);
5737       inside_init
5738         = convert_for_assignment (init_loc, type, inside_init, origtype,
5739                                   ic_init, null_pointer_constant,
5740                                   NULL_TREE, NULL_TREE, 0);
5741
5742       /* Check to see if we have already given an error message.  */
5743       if (inside_init == error_mark_node)
5744         ;
5745       else if (require_constant && !TREE_CONSTANT (inside_init))
5746         {
5747           error_init ("initializer element is not constant");
5748           inside_init = error_mark_node;
5749         }
5750       else if (require_constant
5751                && !initializer_constant_valid_p (inside_init,
5752                                                  TREE_TYPE (inside_init)))
5753         {
5754           error_init ("initializer element is not computable at load time");
5755           inside_init = error_mark_node;
5756         }
5757       else if (require_constant && !maybe_const)
5758         pedwarn_init (init_loc, 0,
5759                       "initializer element is not a constant expression");
5760
5761       return inside_init;
5762     }
5763
5764   /* Come here only for records and arrays.  */
5765
5766   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5767     {
5768       error_init ("variable-sized object may not be initialized");
5769       return error_mark_node;
5770     }
5771
5772   error_init ("invalid initializer");
5773   return error_mark_node;
5774 }
5775 \f
5776 /* Handle initializers that use braces.  */
5777
5778 /* Type of object we are accumulating a constructor for.
5779    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5780 static tree constructor_type;
5781
5782 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5783    left to fill.  */
5784 static tree constructor_fields;
5785
5786 /* For an ARRAY_TYPE, this is the specified index
5787    at which to store the next element we get.  */
5788 static tree constructor_index;
5789
5790 /* For an ARRAY_TYPE, this is the maximum index.  */
5791 static tree constructor_max_index;
5792
5793 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5794 static tree constructor_unfilled_fields;
5795
5796 /* For an ARRAY_TYPE, this is the index of the first element
5797    not yet written out.  */
5798 static tree constructor_unfilled_index;
5799
5800 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5801    This is so we can generate gaps between fields, when appropriate.  */
5802 static tree constructor_bit_index;
5803
5804 /* If we are saving up the elements rather than allocating them,
5805    this is the list of elements so far (in reverse order,
5806    most recent first).  */
5807 static VEC(constructor_elt,gc) *constructor_elements;
5808
5809 /* 1 if constructor should be incrementally stored into a constructor chain,
5810    0 if all the elements should be kept in AVL tree.  */
5811 static int constructor_incremental;
5812
5813 /* 1 if so far this constructor's elements are all compile-time constants.  */
5814 static int constructor_constant;
5815
5816 /* 1 if so far this constructor's elements are all valid address constants.  */
5817 static int constructor_simple;
5818
5819 /* 1 if this constructor has an element that cannot be part of a
5820    constant expression.  */
5821 static int constructor_nonconst;
5822
5823 /* 1 if this constructor is erroneous so far.  */
5824 static int constructor_erroneous;
5825
5826 /* Structure for managing pending initializer elements, organized as an
5827    AVL tree.  */
5828
5829 struct init_node
5830 {
5831   struct init_node *left, *right;
5832   struct init_node *parent;
5833   int balance;
5834   tree purpose;
5835   tree value;
5836   tree origtype;
5837 };
5838
5839 /* Tree of pending elements at this constructor level.
5840    These are elements encountered out of order
5841    which belong at places we haven't reached yet in actually
5842    writing the output.
5843    Will never hold tree nodes across GC runs.  */
5844 static struct init_node *constructor_pending_elts;
5845
5846 /* The SPELLING_DEPTH of this constructor.  */
5847 static int constructor_depth;
5848
5849 /* DECL node for which an initializer is being read.
5850    0 means we are reading a constructor expression
5851    such as (struct foo) {...}.  */
5852 static tree constructor_decl;
5853
5854 /* Nonzero if this is an initializer for a top-level decl.  */
5855 static int constructor_top_level;
5856
5857 /* Nonzero if there were any member designators in this initializer.  */
5858 static int constructor_designated;
5859
5860 /* Nesting depth of designator list.  */
5861 static int designator_depth;
5862
5863 /* Nonzero if there were diagnosed errors in this designator list.  */
5864 static int designator_erroneous;
5865
5866 \f
5867 /* This stack has a level for each implicit or explicit level of
5868    structuring in the initializer, including the outermost one.  It
5869    saves the values of most of the variables above.  */
5870
5871 struct constructor_range_stack;
5872
5873 struct constructor_stack
5874 {
5875   struct constructor_stack *next;
5876   tree type;
5877   tree fields;
5878   tree index;
5879   tree max_index;
5880   tree unfilled_index;
5881   tree unfilled_fields;
5882   tree bit_index;
5883   VEC(constructor_elt,gc) *elements;
5884   struct init_node *pending_elts;
5885   int offset;
5886   int depth;
5887   /* If value nonzero, this value should replace the entire
5888      constructor at this level.  */
5889   struct c_expr replacement_value;
5890   struct constructor_range_stack *range_stack;
5891   char constant;
5892   char simple;
5893   char nonconst;
5894   char implicit;
5895   char erroneous;
5896   char outer;
5897   char incremental;
5898   char designated;
5899 };
5900
5901 static struct constructor_stack *constructor_stack;
5902
5903 /* This stack represents designators from some range designator up to
5904    the last designator in the list.  */
5905
5906 struct constructor_range_stack
5907 {
5908   struct constructor_range_stack *next, *prev;
5909   struct constructor_stack *stack;
5910   tree range_start;
5911   tree index;
5912   tree range_end;
5913   tree fields;
5914 };
5915
5916 static struct constructor_range_stack *constructor_range_stack;
5917
5918 /* This stack records separate initializers that are nested.
5919    Nested initializers can't happen in ANSI C, but GNU C allows them
5920    in cases like { ... (struct foo) { ... } ... }.  */
5921
5922 struct initializer_stack
5923 {
5924   struct initializer_stack *next;
5925   tree decl;
5926   struct constructor_stack *constructor_stack;
5927   struct constructor_range_stack *constructor_range_stack;
5928   VEC(constructor_elt,gc) *elements;
5929   struct spelling *spelling;
5930   struct spelling *spelling_base;
5931   int spelling_size;
5932   char top_level;
5933   char require_constant_value;
5934   char require_constant_elements;
5935 };
5936
5937 static struct initializer_stack *initializer_stack;
5938 \f
5939 /* Prepare to parse and output the initializer for variable DECL.  */
5940
5941 void
5942 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5943 {
5944   const char *locus;
5945   struct initializer_stack *p = XNEW (struct initializer_stack);
5946
5947   p->decl = constructor_decl;
5948   p->require_constant_value = require_constant_value;
5949   p->require_constant_elements = require_constant_elements;
5950   p->constructor_stack = constructor_stack;
5951   p->constructor_range_stack = constructor_range_stack;
5952   p->elements = constructor_elements;
5953   p->spelling = spelling;
5954   p->spelling_base = spelling_base;
5955   p->spelling_size = spelling_size;
5956   p->top_level = constructor_top_level;
5957   p->next = initializer_stack;
5958   initializer_stack = p;
5959
5960   constructor_decl = decl;
5961   constructor_designated = 0;
5962   constructor_top_level = top_level;
5963
5964   if (decl != 0 && decl != error_mark_node)
5965     {
5966       require_constant_value = TREE_STATIC (decl);
5967       require_constant_elements
5968         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5969            /* For a scalar, you can always use any value to initialize,
5970               even within braces.  */
5971            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5972                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5973                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5974                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5975       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
5976     }
5977   else
5978     {
5979       require_constant_value = 0;
5980       require_constant_elements = 0;
5981       locus = _("(anonymous)");
5982     }
5983
5984   constructor_stack = 0;
5985   constructor_range_stack = 0;
5986
5987   missing_braces_mentioned = 0;
5988
5989   spelling_base = 0;
5990   spelling_size = 0;
5991   RESTORE_SPELLING_DEPTH (0);
5992
5993   if (locus)
5994     push_string (locus);
5995 }
5996
5997 void
5998 finish_init (void)
5999 {
6000   struct initializer_stack *p = initializer_stack;
6001
6002   /* Free the whole constructor stack of this initializer.  */
6003   while (constructor_stack)
6004     {
6005       struct constructor_stack *q = constructor_stack;
6006       constructor_stack = q->next;
6007       free (q);
6008     }
6009
6010   gcc_assert (!constructor_range_stack);
6011
6012   /* Pop back to the data of the outer initializer (if any).  */
6013   free (spelling_base);
6014
6015   constructor_decl = p->decl;
6016   require_constant_value = p->require_constant_value;
6017   require_constant_elements = p->require_constant_elements;
6018   constructor_stack = p->constructor_stack;
6019   constructor_range_stack = p->constructor_range_stack;
6020   constructor_elements = p->elements;
6021   spelling = p->spelling;
6022   spelling_base = p->spelling_base;
6023   spelling_size = p->spelling_size;
6024   constructor_top_level = p->top_level;
6025   initializer_stack = p->next;
6026   free (p);
6027 }
6028 \f
6029 /* Call here when we see the initializer is surrounded by braces.
6030    This is instead of a call to push_init_level;
6031    it is matched by a call to pop_init_level.
6032
6033    TYPE is the type to initialize, for a constructor expression.
6034    For an initializer for a decl, TYPE is zero.  */
6035
6036 void
6037 really_start_incremental_init (tree type)
6038 {
6039   struct constructor_stack *p = XNEW (struct constructor_stack);
6040
6041   if (type == 0)
6042     type = TREE_TYPE (constructor_decl);
6043
6044   if (TREE_CODE (type) == VECTOR_TYPE
6045       && TYPE_VECTOR_OPAQUE (type))
6046     error ("opaque vector types cannot be initialized");
6047
6048   p->type = constructor_type;
6049   p->fields = constructor_fields;
6050   p->index = constructor_index;
6051   p->max_index = constructor_max_index;
6052   p->unfilled_index = constructor_unfilled_index;
6053   p->unfilled_fields = constructor_unfilled_fields;
6054   p->bit_index = constructor_bit_index;
6055   p->elements = constructor_elements;
6056   p->constant = constructor_constant;
6057   p->simple = constructor_simple;
6058   p->nonconst = constructor_nonconst;
6059   p->erroneous = constructor_erroneous;
6060   p->pending_elts = constructor_pending_elts;
6061   p->depth = constructor_depth;
6062   p->replacement_value.value = 0;
6063   p->replacement_value.original_code = ERROR_MARK;
6064   p->replacement_value.original_type = NULL;
6065   p->implicit = 0;
6066   p->range_stack = 0;
6067   p->outer = 0;
6068   p->incremental = constructor_incremental;
6069   p->designated = constructor_designated;
6070   p->next = 0;
6071   constructor_stack = p;
6072
6073   constructor_constant = 1;
6074   constructor_simple = 1;
6075   constructor_nonconst = 0;
6076   constructor_depth = SPELLING_DEPTH ();
6077   constructor_elements = 0;
6078   constructor_pending_elts = 0;
6079   constructor_type = type;
6080   constructor_incremental = 1;
6081   constructor_designated = 0;
6082   designator_depth = 0;
6083   designator_erroneous = 0;
6084
6085   if (TREE_CODE (constructor_type) == RECORD_TYPE
6086       || TREE_CODE (constructor_type) == UNION_TYPE)
6087     {
6088       constructor_fields = TYPE_FIELDS (constructor_type);
6089       /* Skip any nameless bit fields at the beginning.  */
6090       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6091              && DECL_NAME (constructor_fields) == 0)
6092         constructor_fields = TREE_CHAIN (constructor_fields);
6093
6094       constructor_unfilled_fields = constructor_fields;
6095       constructor_bit_index = bitsize_zero_node;
6096     }
6097   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6098     {
6099       if (TYPE_DOMAIN (constructor_type))
6100         {
6101           constructor_max_index
6102             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6103
6104           /* Detect non-empty initializations of zero-length arrays.  */
6105           if (constructor_max_index == NULL_TREE
6106               && TYPE_SIZE (constructor_type))
6107             constructor_max_index = build_int_cst (NULL_TREE, -1);
6108
6109           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6110              to initialize VLAs will cause a proper error; avoid tree
6111              checking errors as well by setting a safe value.  */
6112           if (constructor_max_index
6113               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6114             constructor_max_index = build_int_cst (NULL_TREE, -1);
6115
6116           constructor_index
6117             = convert (bitsizetype,
6118                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6119         }
6120       else
6121         {
6122           constructor_index = bitsize_zero_node;
6123           constructor_max_index = NULL_TREE;
6124         }
6125
6126       constructor_unfilled_index = constructor_index;
6127     }
6128   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6129     {
6130       /* Vectors are like simple fixed-size arrays.  */
6131       constructor_max_index =
6132         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6133       constructor_index = bitsize_zero_node;
6134       constructor_unfilled_index = constructor_index;
6135     }
6136   else
6137     {
6138       /* Handle the case of int x = {5}; */
6139       constructor_fields = constructor_type;
6140       constructor_unfilled_fields = constructor_type;
6141     }
6142 }
6143 \f
6144 /* Push down into a subobject, for initialization.
6145    If this is for an explicit set of braces, IMPLICIT is 0.
6146    If it is because the next element belongs at a lower level,
6147    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6148
6149 void
6150 push_init_level (int implicit)
6151 {
6152   struct constructor_stack *p;
6153   tree value = NULL_TREE;
6154
6155   /* If we've exhausted any levels that didn't have braces,
6156      pop them now.  If implicit == 1, this will have been done in
6157      process_init_element; do not repeat it here because in the case
6158      of excess initializers for an empty aggregate this leads to an
6159      infinite cycle of popping a level and immediately recreating
6160      it.  */
6161   if (implicit != 1)
6162     {
6163       while (constructor_stack->implicit)
6164         {
6165           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6166                || TREE_CODE (constructor_type) == UNION_TYPE)
6167               && constructor_fields == 0)
6168             process_init_element (pop_init_level (1), true);
6169           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6170                    && constructor_max_index
6171                    && tree_int_cst_lt (constructor_max_index,
6172                                        constructor_index))
6173             process_init_element (pop_init_level (1), true);
6174           else
6175             break;
6176         }
6177     }
6178
6179   /* Unless this is an explicit brace, we need to preserve previous
6180      content if any.  */
6181   if (implicit)
6182     {
6183       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6184            || TREE_CODE (constructor_type) == UNION_TYPE)
6185           && constructor_fields)
6186         value = find_init_member (constructor_fields);
6187       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6188         value = find_init_member (constructor_index);
6189     }
6190
6191   p = XNEW (struct constructor_stack);
6192   p->type = constructor_type;
6193   p->fields = constructor_fields;
6194   p->index = constructor_index;
6195   p->max_index = constructor_max_index;
6196   p->unfilled_index = constructor_unfilled_index;
6197   p->unfilled_fields = constructor_unfilled_fields;
6198   p->bit_index = constructor_bit_index;
6199   p->elements = constructor_elements;
6200   p->constant = constructor_constant;
6201   p->simple = constructor_simple;
6202   p->nonconst = constructor_nonconst;
6203   p->erroneous = constructor_erroneous;
6204   p->pending_elts = constructor_pending_elts;
6205   p->depth = constructor_depth;
6206   p->replacement_value.value = 0;
6207   p->replacement_value.original_code = ERROR_MARK;
6208   p->replacement_value.original_type = NULL;
6209   p->implicit = implicit;
6210   p->outer = 0;
6211   p->incremental = constructor_incremental;
6212   p->designated = constructor_designated;
6213   p->next = constructor_stack;
6214   p->range_stack = 0;
6215   constructor_stack = p;
6216
6217   constructor_constant = 1;
6218   constructor_simple = 1;
6219   constructor_nonconst = 0;
6220   constructor_depth = SPELLING_DEPTH ();
6221   constructor_elements = 0;
6222   constructor_incremental = 1;
6223   constructor_designated = 0;
6224   constructor_pending_elts = 0;
6225   if (!implicit)
6226     {
6227       p->range_stack = constructor_range_stack;
6228       constructor_range_stack = 0;
6229       designator_depth = 0;
6230       designator_erroneous = 0;
6231     }
6232
6233   /* Don't die if an entire brace-pair level is superfluous
6234      in the containing level.  */
6235   if (constructor_type == 0)
6236     ;
6237   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6238            || TREE_CODE (constructor_type) == UNION_TYPE)
6239     {
6240       /* Don't die if there are extra init elts at the end.  */
6241       if (constructor_fields == 0)
6242         constructor_type = 0;
6243       else
6244         {
6245           constructor_type = TREE_TYPE (constructor_fields);
6246           push_member_name (constructor_fields);
6247           constructor_depth++;
6248         }
6249     }
6250   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6251     {
6252       constructor_type = TREE_TYPE (constructor_type);
6253       push_array_bounds (tree_low_cst (constructor_index, 1));
6254       constructor_depth++;
6255     }
6256
6257   if (constructor_type == 0)
6258     {
6259       error_init ("extra brace group at end of initializer");
6260       constructor_fields = 0;
6261       constructor_unfilled_fields = 0;
6262       return;
6263     }
6264
6265   if (value && TREE_CODE (value) == CONSTRUCTOR)
6266     {
6267       constructor_constant = TREE_CONSTANT (value);
6268       constructor_simple = TREE_STATIC (value);
6269       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6270       constructor_elements = CONSTRUCTOR_ELTS (value);
6271       if (!VEC_empty (constructor_elt, constructor_elements)
6272           && (TREE_CODE (constructor_type) == RECORD_TYPE
6273               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6274         set_nonincremental_init ();
6275     }
6276
6277   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6278     {
6279       missing_braces_mentioned = 1;
6280       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6281     }
6282
6283   if (TREE_CODE (constructor_type) == RECORD_TYPE
6284            || TREE_CODE (constructor_type) == UNION_TYPE)
6285     {
6286       constructor_fields = TYPE_FIELDS (constructor_type);
6287       /* Skip any nameless bit fields at the beginning.  */
6288       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6289              && DECL_NAME (constructor_fields) == 0)
6290         constructor_fields = TREE_CHAIN (constructor_fields);
6291
6292       constructor_unfilled_fields = constructor_fields;
6293       constructor_bit_index = bitsize_zero_node;
6294     }
6295   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6296     {
6297       /* Vectors are like simple fixed-size arrays.  */
6298       constructor_max_index =
6299         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6300       constructor_index = convert (bitsizetype, integer_zero_node);
6301       constructor_unfilled_index = constructor_index;
6302     }
6303   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6304     {
6305       if (TYPE_DOMAIN (constructor_type))
6306         {
6307           constructor_max_index
6308             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6309
6310           /* Detect non-empty initializations of zero-length arrays.  */
6311           if (constructor_max_index == NULL_TREE
6312               && TYPE_SIZE (constructor_type))
6313             constructor_max_index = build_int_cst (NULL_TREE, -1);
6314
6315           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6316              to initialize VLAs will cause a proper error; avoid tree
6317              checking errors as well by setting a safe value.  */
6318           if (constructor_max_index
6319               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6320             constructor_max_index = build_int_cst (NULL_TREE, -1);
6321
6322           constructor_index
6323             = convert (bitsizetype,
6324                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6325         }
6326       else
6327         constructor_index = bitsize_zero_node;
6328
6329       constructor_unfilled_index = constructor_index;
6330       if (value && TREE_CODE (value) == STRING_CST)
6331         {
6332           /* We need to split the char/wchar array into individual
6333              characters, so that we don't have to special case it
6334              everywhere.  */
6335           set_nonincremental_init_from_string (value);
6336         }
6337     }
6338   else
6339     {
6340       if (constructor_type != error_mark_node)
6341         warning_init (0, "braces around scalar initializer");
6342       constructor_fields = constructor_type;
6343       constructor_unfilled_fields = constructor_type;
6344     }
6345 }
6346
6347 /* At the end of an implicit or explicit brace level,
6348    finish up that level of constructor.  If a single expression
6349    with redundant braces initialized that level, return the
6350    c_expr structure for that expression.  Otherwise, the original_code
6351    element is set to ERROR_MARK.
6352    If we were outputting the elements as they are read, return 0 as the value
6353    from inner levels (process_init_element ignores that),
6354    but return error_mark_node as the value from the outermost level
6355    (that's what we want to put in DECL_INITIAL).
6356    Otherwise, return a CONSTRUCTOR expression as the value.  */
6357
6358 struct c_expr
6359 pop_init_level (int implicit)
6360 {
6361   struct constructor_stack *p;
6362   struct c_expr ret;
6363   ret.value = 0;
6364   ret.original_code = ERROR_MARK;
6365   ret.original_type = NULL;
6366
6367   if (implicit == 0)
6368     {
6369       /* When we come to an explicit close brace,
6370          pop any inner levels that didn't have explicit braces.  */
6371       while (constructor_stack->implicit)
6372         process_init_element (pop_init_level (1), true);
6373
6374       gcc_assert (!constructor_range_stack);
6375     }
6376
6377   /* Now output all pending elements.  */
6378   constructor_incremental = 1;
6379   output_pending_init_elements (1);
6380
6381   p = constructor_stack;
6382
6383   /* Error for initializing a flexible array member, or a zero-length
6384      array member in an inappropriate context.  */
6385   if (constructor_type && constructor_fields
6386       && TREE_CODE (constructor_type) == ARRAY_TYPE
6387       && TYPE_DOMAIN (constructor_type)
6388       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6389     {
6390       /* Silently discard empty initializations.  The parser will
6391          already have pedwarned for empty brackets.  */
6392       if (integer_zerop (constructor_unfilled_index))
6393         constructor_type = NULL_TREE;
6394       else
6395         {
6396           gcc_assert (!TYPE_SIZE (constructor_type));
6397
6398           if (constructor_depth > 2)
6399             error_init ("initialization of flexible array member in a nested context");
6400           else
6401             pedwarn_init (input_location, OPT_pedantic,
6402                           "initialization of a flexible array member");
6403
6404           /* We have already issued an error message for the existence
6405              of a flexible array member not at the end of the structure.
6406              Discard the initializer so that we do not die later.  */
6407           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6408             constructor_type = NULL_TREE;
6409         }
6410     }
6411
6412   /* Warn when some struct elements are implicitly initialized to zero.  */
6413   if (warn_missing_field_initializers
6414       && constructor_type
6415       && TREE_CODE (constructor_type) == RECORD_TYPE
6416       && constructor_unfilled_fields)
6417     {
6418         /* Do not warn for flexible array members or zero-length arrays.  */
6419         while (constructor_unfilled_fields
6420                && (!DECL_SIZE (constructor_unfilled_fields)
6421                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6422           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6423
6424         /* Do not warn if this level of the initializer uses member
6425            designators; it is likely to be deliberate.  */
6426         if (constructor_unfilled_fields && !constructor_designated)
6427           {
6428             push_member_name (constructor_unfilled_fields);
6429             warning_init (OPT_Wmissing_field_initializers,
6430                           "missing initializer");
6431             RESTORE_SPELLING_DEPTH (constructor_depth);
6432           }
6433     }
6434
6435   /* Pad out the end of the structure.  */
6436   if (p->replacement_value.value)
6437     /* If this closes a superfluous brace pair,
6438        just pass out the element between them.  */
6439     ret = p->replacement_value;
6440   else if (constructor_type == 0)
6441     ;
6442   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6443            && TREE_CODE (constructor_type) != UNION_TYPE
6444            && TREE_CODE (constructor_type) != ARRAY_TYPE
6445            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6446     {
6447       /* A nonincremental scalar initializer--just return
6448          the element, after verifying there is just one.  */
6449       if (VEC_empty (constructor_elt,constructor_elements))
6450         {
6451           if (!constructor_erroneous)
6452             error_init ("empty scalar initializer");
6453           ret.value = error_mark_node;
6454         }
6455       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6456         {
6457           error_init ("extra elements in scalar initializer");
6458           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6459         }
6460       else
6461         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6462     }
6463   else
6464     {
6465       if (constructor_erroneous)
6466         ret.value = error_mark_node;
6467       else
6468         {
6469           ret.value = build_constructor (constructor_type,
6470                                          constructor_elements);
6471           if (constructor_constant)
6472             TREE_CONSTANT (ret.value) = 1;
6473           if (constructor_constant && constructor_simple)
6474             TREE_STATIC (ret.value) = 1;
6475           if (constructor_nonconst)
6476             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6477         }
6478     }
6479
6480   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6481     {
6482       if (constructor_nonconst)
6483         ret.original_code = C_MAYBE_CONST_EXPR;
6484       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6485         ret.original_code = ERROR_MARK;
6486     }
6487
6488   constructor_type = p->type;
6489   constructor_fields = p->fields;
6490   constructor_index = p->index;
6491   constructor_max_index = p->max_index;
6492   constructor_unfilled_index = p->unfilled_index;
6493   constructor_unfilled_fields = p->unfilled_fields;
6494   constructor_bit_index = p->bit_index;
6495   constructor_elements = p->elements;
6496   constructor_constant = p->constant;
6497   constructor_simple = p->simple;
6498   constructor_nonconst = p->nonconst;
6499   constructor_erroneous = p->erroneous;
6500   constructor_incremental = p->incremental;
6501   constructor_designated = p->designated;
6502   constructor_pending_elts = p->pending_elts;
6503   constructor_depth = p->depth;
6504   if (!p->implicit)
6505     constructor_range_stack = p->range_stack;
6506   RESTORE_SPELLING_DEPTH (constructor_depth);
6507
6508   constructor_stack = p->next;
6509   free (p);
6510
6511   if (ret.value == 0 && constructor_stack == 0)
6512     ret.value = error_mark_node;
6513   return ret;
6514 }
6515
6516 /* Common handling for both array range and field name designators.
6517    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6518
6519 static int
6520 set_designator (int array)
6521 {
6522   tree subtype;
6523   enum tree_code subcode;
6524
6525   /* Don't die if an entire brace-pair level is superfluous
6526      in the containing level.  */
6527   if (constructor_type == 0)
6528     return 1;
6529
6530   /* If there were errors in this designator list already, bail out
6531      silently.  */
6532   if (designator_erroneous)
6533     return 1;
6534
6535   if (!designator_depth)
6536     {
6537       gcc_assert (!constructor_range_stack);
6538
6539       /* Designator list starts at the level of closest explicit
6540          braces.  */
6541       while (constructor_stack->implicit)
6542         process_init_element (pop_init_level (1), true);
6543       constructor_designated = 1;
6544       return 0;
6545     }
6546
6547   switch (TREE_CODE (constructor_type))
6548     {
6549     case  RECORD_TYPE:
6550     case  UNION_TYPE:
6551       subtype = TREE_TYPE (constructor_fields);
6552       if (subtype != error_mark_node)
6553         subtype = TYPE_MAIN_VARIANT (subtype);
6554       break;
6555     case ARRAY_TYPE:
6556       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6557       break;
6558     default:
6559       gcc_unreachable ();
6560     }
6561
6562   subcode = TREE_CODE (subtype);
6563   if (array && subcode != ARRAY_TYPE)
6564     {
6565       error_init ("array index in non-array initializer");
6566       return 1;
6567     }
6568   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6569     {
6570       error_init ("field name not in record or union initializer");
6571       return 1;
6572     }
6573
6574   constructor_designated = 1;
6575   push_init_level (2);
6576   return 0;
6577 }
6578
6579 /* If there are range designators in designator list, push a new designator
6580    to constructor_range_stack.  RANGE_END is end of such stack range or
6581    NULL_TREE if there is no range designator at this level.  */
6582
6583 static void
6584 push_range_stack (tree range_end)
6585 {
6586   struct constructor_range_stack *p;
6587
6588   p = GGC_NEW (struct constructor_range_stack);
6589   p->prev = constructor_range_stack;
6590   p->next = 0;
6591   p->fields = constructor_fields;
6592   p->range_start = constructor_index;
6593   p->index = constructor_index;
6594   p->stack = constructor_stack;
6595   p->range_end = range_end;
6596   if (constructor_range_stack)
6597     constructor_range_stack->next = p;
6598   constructor_range_stack = p;
6599 }
6600
6601 /* Within an array initializer, specify the next index to be initialized.
6602    FIRST is that index.  If LAST is nonzero, then initialize a range
6603    of indices, running from FIRST through LAST.  */
6604
6605 void
6606 set_init_index (tree first, tree last)
6607 {
6608   if (set_designator (1))
6609     return;
6610
6611   designator_erroneous = 1;
6612
6613   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6614       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6615     {
6616       error_init ("array index in initializer not of integer type");
6617       return;
6618     }
6619
6620   if (TREE_CODE (first) != INTEGER_CST)
6621     {
6622       first = c_fully_fold (first, false, NULL);
6623       if (TREE_CODE (first) == INTEGER_CST)
6624         pedwarn_init (input_location, OPT_pedantic,
6625                       "array index in initializer is not "
6626                       "an integer constant expression");
6627     }
6628
6629   if (last && TREE_CODE (last) != INTEGER_CST)
6630     {
6631       last = c_fully_fold (last, false, NULL);
6632       if (TREE_CODE (last) == INTEGER_CST)
6633         pedwarn_init (input_location, OPT_pedantic,
6634                       "array index in initializer is not "
6635                       "an integer constant expression");
6636     }
6637
6638   if (TREE_CODE (first) != INTEGER_CST)
6639     error_init ("nonconstant array index in initializer");
6640   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6641     error_init ("nonconstant array index in initializer");
6642   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6643     error_init ("array index in non-array initializer");
6644   else if (tree_int_cst_sgn (first) == -1)
6645     error_init ("array index in initializer exceeds array bounds");
6646   else if (constructor_max_index
6647            && tree_int_cst_lt (constructor_max_index, first))
6648     error_init ("array index in initializer exceeds array bounds");
6649   else
6650     {
6651       constant_expression_warning (first);
6652       if (last)
6653         constant_expression_warning (last);
6654       constructor_index = convert (bitsizetype, first);
6655
6656       if (last)
6657         {
6658           if (tree_int_cst_equal (first, last))
6659             last = 0;
6660           else if (tree_int_cst_lt (last, first))
6661             {
6662               error_init ("empty index range in initializer");
6663               last = 0;
6664             }
6665           else
6666             {
6667               last = convert (bitsizetype, last);
6668               if (constructor_max_index != 0
6669                   && tree_int_cst_lt (constructor_max_index, last))
6670                 {
6671                   error_init ("array index range in initializer exceeds array bounds");
6672                   last = 0;
6673                 }
6674             }
6675         }
6676
6677       designator_depth++;
6678       designator_erroneous = 0;
6679       if (constructor_range_stack || last)
6680         push_range_stack (last);
6681     }
6682 }
6683
6684 /* Within a struct initializer, specify the next field to be initialized.  */
6685
6686 void
6687 set_init_label (tree fieldname)
6688 {
6689   tree tail;
6690
6691   if (set_designator (0))
6692     return;
6693
6694   designator_erroneous = 1;
6695
6696   if (TREE_CODE (constructor_type) != RECORD_TYPE
6697       && TREE_CODE (constructor_type) != UNION_TYPE)
6698     {
6699       error_init ("field name not in record or union initializer");
6700       return;
6701     }
6702
6703   for (tail = TYPE_FIELDS (constructor_type); tail;
6704        tail = TREE_CHAIN (tail))
6705     {
6706       if (DECL_NAME (tail) == fieldname)
6707         break;
6708     }
6709
6710   if (tail == 0)
6711     error ("unknown field %qE specified in initializer", fieldname);
6712   else
6713     {
6714       constructor_fields = tail;
6715       designator_depth++;
6716       designator_erroneous = 0;
6717       if (constructor_range_stack)
6718         push_range_stack (NULL_TREE);
6719     }
6720 }
6721 \f
6722 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6723    identifies the initializer, either array index or field in a structure.
6724    VALUE is the value of that index or field.  If ORIGTYPE is not
6725    NULL_TREE, it is the original type of VALUE.
6726
6727    IMPLICIT is true if value comes from pop_init_level (1),
6728    the new initializer has been merged with the existing one
6729    and thus no warnings should be emitted about overriding an
6730    existing initializer.  */
6731
6732 static void
6733 add_pending_init (tree purpose, tree value, tree origtype, bool implicit)
6734 {
6735   struct init_node *p, **q, *r;
6736
6737   q = &constructor_pending_elts;
6738   p = 0;
6739
6740   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6741     {
6742       while (*q != 0)
6743         {
6744           p = *q;
6745           if (tree_int_cst_lt (purpose, p->purpose))
6746             q = &p->left;
6747           else if (tree_int_cst_lt (p->purpose, purpose))
6748             q = &p->right;
6749           else
6750             {
6751               if (!implicit)
6752                 {
6753                   if (TREE_SIDE_EFFECTS (p->value))
6754                     warning_init (0, "initialized field with side-effects overwritten");
6755                   else if (warn_override_init)
6756                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6757                 }
6758               p->value = value;
6759               p->origtype = origtype;
6760               return;
6761             }
6762         }
6763     }
6764   else
6765     {
6766       tree bitpos;
6767
6768       bitpos = bit_position (purpose);
6769       while (*q != NULL)
6770         {
6771           p = *q;
6772           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6773             q = &p->left;
6774           else if (p->purpose != purpose)
6775             q = &p->right;
6776           else
6777             {
6778               if (!implicit)
6779                 {
6780                   if (TREE_SIDE_EFFECTS (p->value))
6781                     warning_init (0, "initialized field with side-effects overwritten");
6782                   else if (warn_override_init)
6783                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6784                 }
6785               p->value = value;
6786               p->origtype = origtype;
6787               return;
6788             }
6789         }
6790     }
6791
6792   r = GGC_NEW (struct init_node);
6793   r->purpose = purpose;
6794   r->value = value;
6795   r->origtype = origtype;
6796
6797   *q = r;
6798   r->parent = p;
6799   r->left = 0;
6800   r->right = 0;
6801   r->balance = 0;
6802
6803   while (p)
6804     {
6805       struct init_node *s;
6806
6807       if (r == p->left)
6808         {
6809           if (p->balance == 0)
6810             p->balance = -1;
6811           else if (p->balance < 0)
6812             {
6813               if (r->balance < 0)
6814                 {
6815                   /* L rotation.  */
6816                   p->left = r->right;
6817                   if (p->left)
6818                     p->left->parent = p;
6819                   r->right = p;
6820
6821                   p->balance = 0;
6822                   r->balance = 0;
6823
6824                   s = p->parent;
6825                   p->parent = r;
6826                   r->parent = s;
6827                   if (s)
6828                     {
6829                       if (s->left == p)
6830                         s->left = r;
6831                       else
6832                         s->right = r;
6833                     }
6834                   else
6835                     constructor_pending_elts = r;
6836                 }
6837               else
6838                 {
6839                   /* LR rotation.  */
6840                   struct init_node *t = r->right;
6841
6842                   r->right = t->left;
6843                   if (r->right)
6844                     r->right->parent = r;
6845                   t->left = r;
6846
6847                   p->left = t->right;
6848                   if (p->left)
6849                     p->left->parent = p;
6850                   t->right = p;
6851
6852                   p->balance = t->balance < 0;
6853                   r->balance = -(t->balance > 0);
6854                   t->balance = 0;
6855
6856                   s = p->parent;
6857                   p->parent = t;
6858                   r->parent = t;
6859                   t->parent = s;
6860                   if (s)
6861                     {
6862                       if (s->left == p)
6863                         s->left = t;
6864                       else
6865                         s->right = t;
6866                     }
6867                   else
6868                     constructor_pending_elts = t;
6869                 }
6870               break;
6871             }
6872           else
6873             {
6874               /* p->balance == +1; growth of left side balances the node.  */
6875               p->balance = 0;
6876               break;
6877             }
6878         }
6879       else /* r == p->right */
6880         {
6881           if (p->balance == 0)
6882             /* Growth propagation from right side.  */
6883             p->balance++;
6884           else if (p->balance > 0)
6885             {
6886               if (r->balance > 0)
6887                 {
6888                   /* R rotation.  */
6889                   p->right = r->left;
6890                   if (p->right)
6891                     p->right->parent = p;
6892                   r->left = p;
6893
6894                   p->balance = 0;
6895                   r->balance = 0;
6896
6897                   s = p->parent;
6898                   p->parent = r;
6899                   r->parent = s;
6900                   if (s)
6901                     {
6902                       if (s->left == p)
6903                         s->left = r;
6904                       else
6905                         s->right = r;
6906                     }
6907                   else
6908                     constructor_pending_elts = r;
6909                 }
6910               else /* r->balance == -1 */
6911                 {
6912                   /* RL rotation */
6913                   struct init_node *t = r->left;
6914
6915                   r->left = t->right;
6916                   if (r->left)
6917                     r->left->parent = r;
6918                   t->right = r;
6919
6920                   p->right = t->left;
6921                   if (p->right)
6922                     p->right->parent = p;
6923                   t->left = p;
6924
6925                   r->balance = (t->balance < 0);
6926                   p->balance = -(t->balance > 0);
6927                   t->balance = 0;
6928
6929                   s = p->parent;
6930                   p->parent = t;
6931                   r->parent = t;
6932                   t->parent = s;
6933                   if (s)
6934                     {
6935                       if (s->left == p)
6936                         s->left = t;
6937                       else
6938                         s->right = t;
6939                     }
6940                   else
6941                     constructor_pending_elts = t;
6942                 }
6943               break;
6944             }
6945           else
6946             {
6947               /* p->balance == -1; growth of right side balances the node.  */
6948               p->balance = 0;
6949               break;
6950             }
6951         }
6952
6953       r = p;
6954       p = p->parent;
6955     }
6956 }
6957
6958 /* Build AVL tree from a sorted chain.  */
6959
6960 static void
6961 set_nonincremental_init (void)
6962 {
6963   unsigned HOST_WIDE_INT ix;
6964   tree index, value;
6965
6966   if (TREE_CODE (constructor_type) != RECORD_TYPE
6967       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6968     return;
6969
6970   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6971     add_pending_init (index, value, NULL_TREE, false);
6972   constructor_elements = 0;
6973   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6974     {
6975       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6976       /* Skip any nameless bit fields at the beginning.  */
6977       while (constructor_unfilled_fields != 0
6978              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6979              && DECL_NAME (constructor_unfilled_fields) == 0)
6980         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6981
6982     }
6983   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6984     {
6985       if (TYPE_DOMAIN (constructor_type))
6986         constructor_unfilled_index
6987             = convert (bitsizetype,
6988                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6989       else
6990         constructor_unfilled_index = bitsize_zero_node;
6991     }
6992   constructor_incremental = 0;
6993 }
6994
6995 /* Build AVL tree from a string constant.  */
6996
6997 static void
6998 set_nonincremental_init_from_string (tree str)
6999 {
7000   tree value, purpose, type;
7001   HOST_WIDE_INT val[2];
7002   const char *p, *end;
7003   int byte, wchar_bytes, charwidth, bitpos;
7004
7005   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7006
7007   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7008   charwidth = TYPE_PRECISION (char_type_node);
7009   type = TREE_TYPE (constructor_type);
7010   p = TREE_STRING_POINTER (str);
7011   end = p + TREE_STRING_LENGTH (str);
7012
7013   for (purpose = bitsize_zero_node;
7014        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7015        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7016     {
7017       if (wchar_bytes == 1)
7018         {
7019           val[1] = (unsigned char) *p++;
7020           val[0] = 0;
7021         }
7022       else
7023         {
7024           val[0] = 0;
7025           val[1] = 0;
7026           for (byte = 0; byte < wchar_bytes; byte++)
7027             {
7028               if (BYTES_BIG_ENDIAN)
7029                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7030               else
7031                 bitpos = byte * charwidth;
7032               val[bitpos < HOST_BITS_PER_WIDE_INT]
7033                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7034                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7035             }
7036         }
7037
7038       if (!TYPE_UNSIGNED (type))
7039         {
7040           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7041           if (bitpos < HOST_BITS_PER_WIDE_INT)
7042             {
7043               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7044                 {
7045                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7046                   val[0] = -1;
7047                 }
7048             }
7049           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7050             {
7051               if (val[1] < 0)
7052                 val[0] = -1;
7053             }
7054           else if (val[0] & (((HOST_WIDE_INT) 1)
7055                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7056             val[0] |= ((HOST_WIDE_INT) -1)
7057                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7058         }
7059
7060       value = build_int_cst_wide (type, val[1], val[0]);
7061       add_pending_init (purpose, value, NULL_TREE, false);
7062     }
7063
7064   constructor_incremental = 0;
7065 }
7066
7067 /* Return value of FIELD in pending initializer or zero if the field was
7068    not initialized yet.  */
7069
7070 static tree
7071 find_init_member (tree field)
7072 {
7073   struct init_node *p;
7074
7075   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7076     {
7077       if (constructor_incremental
7078           && tree_int_cst_lt (field, constructor_unfilled_index))
7079         set_nonincremental_init ();
7080
7081       p = constructor_pending_elts;
7082       while (p)
7083         {
7084           if (tree_int_cst_lt (field, p->purpose))
7085             p = p->left;
7086           else if (tree_int_cst_lt (p->purpose, field))
7087             p = p->right;
7088           else
7089             return p->value;
7090         }
7091     }
7092   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7093     {
7094       tree bitpos = bit_position (field);
7095
7096       if (constructor_incremental
7097           && (!constructor_unfilled_fields
7098               || tree_int_cst_lt (bitpos,
7099                                   bit_position (constructor_unfilled_fields))))
7100         set_nonincremental_init ();
7101
7102       p = constructor_pending_elts;
7103       while (p)
7104         {
7105           if (field == p->purpose)
7106             return p->value;
7107           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7108             p = p->left;
7109           else
7110             p = p->right;
7111         }
7112     }
7113   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7114     {
7115       if (!VEC_empty (constructor_elt, constructor_elements)
7116           && (VEC_last (constructor_elt, constructor_elements)->index
7117               == field))
7118         return VEC_last (constructor_elt, constructor_elements)->value;
7119     }
7120   return 0;
7121 }
7122
7123 /* "Output" the next constructor element.
7124    At top level, really output it to assembler code now.
7125    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7126    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7127    TYPE is the data type that the containing data type wants here.
7128    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7129    If VALUE is a string constant, STRICT_STRING is true if it is
7130    unparenthesized or we should not warn here for it being parenthesized.
7131    For other types of VALUE, STRICT_STRING is not used.
7132
7133    PENDING if non-nil means output pending elements that belong
7134    right after this element.  (PENDING is normally 1;
7135    it is 0 while outputting pending elements, to avoid recursion.)
7136
7137    IMPLICIT is true if value comes from pop_init_level (1),
7138    the new initializer has been merged with the existing one
7139    and thus no warnings should be emitted about overriding an
7140    existing initializer.  */
7141
7142 static void
7143 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7144                      tree field, int pending, bool implicit)
7145 {
7146   tree semantic_type = NULL_TREE;
7147   constructor_elt *celt;
7148   bool maybe_const = true;
7149   bool npc;
7150
7151   if (type == error_mark_node || value == error_mark_node)
7152     {
7153       constructor_erroneous = 1;
7154       return;
7155     }
7156   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7157       && (TREE_CODE (value) == STRING_CST
7158           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7159       && !(TREE_CODE (value) == STRING_CST
7160            && TREE_CODE (type) == ARRAY_TYPE
7161            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7162       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7163                      TYPE_MAIN_VARIANT (type)))
7164     value = array_to_pointer_conversion (input_location, value);
7165
7166   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7167       && require_constant_value && !flag_isoc99 && pending)
7168     {
7169       /* As an extension, allow initializing objects with static storage
7170          duration with compound literals (which are then treated just as
7171          the brace enclosed list they contain).  */
7172       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7173       value = DECL_INITIAL (decl);
7174     }
7175
7176   npc = null_pointer_constant_p (value);
7177   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7178     {
7179       semantic_type = TREE_TYPE (value);
7180       value = TREE_OPERAND (value, 0);
7181     }
7182   value = c_fully_fold (value, require_constant_value, &maybe_const);
7183
7184   if (value == error_mark_node)
7185     constructor_erroneous = 1;
7186   else if (!TREE_CONSTANT (value))
7187     constructor_constant = 0;
7188   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7189            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7190                 || TREE_CODE (constructor_type) == UNION_TYPE)
7191                && DECL_C_BIT_FIELD (field)
7192                && TREE_CODE (value) != INTEGER_CST))
7193     constructor_simple = 0;
7194   if (!maybe_const)
7195     constructor_nonconst = 1;
7196
7197   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7198     {
7199       if (require_constant_value)
7200         {
7201           error_init ("initializer element is not constant");
7202           value = error_mark_node;
7203         }
7204       else if (require_constant_elements)
7205         pedwarn (input_location, 0,
7206                  "initializer element is not computable at load time");
7207     }
7208   else if (!maybe_const
7209            && (require_constant_value || require_constant_elements))
7210     pedwarn_init (input_location, 0,
7211                   "initializer element is not a constant expression");
7212
7213   /* Issue -Wc++-compat warnings about initializing a bitfield with
7214      enum type.  */
7215   if (warn_cxx_compat
7216       && field != NULL_TREE
7217       && TREE_CODE (field) == FIELD_DECL
7218       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7219       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7220           != TYPE_MAIN_VARIANT (type))
7221       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7222     {
7223       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7224       if (checktype != error_mark_node
7225           && (TYPE_MAIN_VARIANT (checktype)
7226               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7227         warning_init (OPT_Wc___compat,
7228                       "enum conversion in initialization is invalid in C++");
7229     }
7230
7231   /* If this field is empty (and not at the end of structure),
7232      don't do anything other than checking the initializer.  */
7233   if (field
7234       && (TREE_TYPE (field) == error_mark_node
7235           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7236               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7237               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7238                   || TREE_CHAIN (field)))))
7239     return;
7240
7241   if (semantic_type)
7242     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7243   value = digest_init (input_location, type, value, origtype, npc,
7244                        strict_string, require_constant_value);
7245   if (value == error_mark_node)
7246     {
7247       constructor_erroneous = 1;
7248       return;
7249     }
7250   if (require_constant_value || require_constant_elements)
7251     constant_expression_warning (value);
7252
7253   /* If this element doesn't come next in sequence,
7254      put it on constructor_pending_elts.  */
7255   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7256       && (!constructor_incremental
7257           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7258     {
7259       if (constructor_incremental
7260           && tree_int_cst_lt (field, constructor_unfilled_index))
7261         set_nonincremental_init ();
7262
7263       add_pending_init (field, value, origtype, implicit);
7264       return;
7265     }
7266   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7267            && (!constructor_incremental
7268                || field != constructor_unfilled_fields))
7269     {
7270       /* We do this for records but not for unions.  In a union,
7271          no matter which field is specified, it can be initialized
7272          right away since it starts at the beginning of the union.  */
7273       if (constructor_incremental)
7274         {
7275           if (!constructor_unfilled_fields)
7276             set_nonincremental_init ();
7277           else
7278             {
7279               tree bitpos, unfillpos;
7280
7281               bitpos = bit_position (field);
7282               unfillpos = bit_position (constructor_unfilled_fields);
7283
7284               if (tree_int_cst_lt (bitpos, unfillpos))
7285                 set_nonincremental_init ();
7286             }
7287         }
7288
7289       add_pending_init (field, value, origtype, implicit);
7290       return;
7291     }
7292   else if (TREE_CODE (constructor_type) == UNION_TYPE
7293            && !VEC_empty (constructor_elt, constructor_elements))
7294     {
7295       if (!implicit)
7296         {
7297           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7298                                            constructor_elements)->value))
7299             warning_init (0,
7300                           "initialized field with side-effects overwritten");
7301           else if (warn_override_init)
7302             warning_init (OPT_Woverride_init, "initialized field overwritten");
7303         }
7304
7305       /* We can have just one union field set.  */
7306       constructor_elements = 0;
7307     }
7308
7309   /* Otherwise, output this element either to
7310      constructor_elements or to the assembler file.  */
7311
7312   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7313   celt->index = field;
7314   celt->value = value;
7315
7316   /* Advance the variable that indicates sequential elements output.  */
7317   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7318     constructor_unfilled_index
7319       = size_binop (PLUS_EXPR, constructor_unfilled_index,
7320                     bitsize_one_node);
7321   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7322     {
7323       constructor_unfilled_fields
7324         = TREE_CHAIN (constructor_unfilled_fields);
7325
7326       /* Skip any nameless bit fields.  */
7327       while (constructor_unfilled_fields != 0
7328              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7329              && DECL_NAME (constructor_unfilled_fields) == 0)
7330         constructor_unfilled_fields =
7331           TREE_CHAIN (constructor_unfilled_fields);
7332     }
7333   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7334     constructor_unfilled_fields = 0;
7335
7336   /* Now output any pending elements which have become next.  */
7337   if (pending)
7338     output_pending_init_elements (0);
7339 }
7340
7341 /* Output any pending elements which have become next.
7342    As we output elements, constructor_unfilled_{fields,index}
7343    advances, which may cause other elements to become next;
7344    if so, they too are output.
7345
7346    If ALL is 0, we return when there are
7347    no more pending elements to output now.
7348
7349    If ALL is 1, we output space as necessary so that
7350    we can output all the pending elements.  */
7351
7352 static void
7353 output_pending_init_elements (int all)
7354 {
7355   struct init_node *elt = constructor_pending_elts;
7356   tree next;
7357
7358  retry:
7359
7360   /* Look through the whole pending tree.
7361      If we find an element that should be output now,
7362      output it.  Otherwise, set NEXT to the element
7363      that comes first among those still pending.  */
7364
7365   next = 0;
7366   while (elt)
7367     {
7368       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7369         {
7370           if (tree_int_cst_equal (elt->purpose,
7371                                   constructor_unfilled_index))
7372             output_init_element (elt->value, elt->origtype, true,
7373                                  TREE_TYPE (constructor_type),
7374                                  constructor_unfilled_index, 0, false);
7375           else if (tree_int_cst_lt (constructor_unfilled_index,
7376                                     elt->purpose))
7377             {
7378               /* Advance to the next smaller node.  */
7379               if (elt->left)
7380                 elt = elt->left;
7381               else
7382                 {
7383                   /* We have reached the smallest node bigger than the
7384                      current unfilled index.  Fill the space first.  */
7385                   next = elt->purpose;
7386                   break;
7387                 }
7388             }
7389           else
7390             {
7391               /* Advance to the next bigger node.  */
7392               if (elt->right)
7393                 elt = elt->right;
7394               else
7395                 {
7396                   /* We have reached the biggest node in a subtree.  Find
7397                      the parent of it, which is the next bigger node.  */
7398                   while (elt->parent && elt->parent->right == elt)
7399                     elt = elt->parent;
7400                   elt = elt->parent;
7401                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7402                                               elt->purpose))
7403                     {
7404                       next = elt->purpose;
7405                       break;
7406                     }
7407                 }
7408             }
7409         }
7410       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7411                || TREE_CODE (constructor_type) == UNION_TYPE)
7412         {
7413           tree ctor_unfilled_bitpos, elt_bitpos;
7414
7415           /* If the current record is complete we are done.  */
7416           if (constructor_unfilled_fields == 0)
7417             break;
7418
7419           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7420           elt_bitpos = bit_position (elt->purpose);
7421           /* We can't compare fields here because there might be empty
7422              fields in between.  */
7423           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7424             {
7425               constructor_unfilled_fields = elt->purpose;
7426               output_init_element (elt->value, elt->origtype, true,
7427                                    TREE_TYPE (elt->purpose),
7428                                    elt->purpose, 0, false);
7429             }
7430           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7431             {
7432               /* Advance to the next smaller node.  */
7433               if (elt->left)
7434                 elt = elt->left;
7435               else
7436                 {
7437                   /* We have reached the smallest node bigger than the
7438                      current unfilled field.  Fill the space first.  */
7439                   next = elt->purpose;
7440                   break;
7441                 }
7442             }
7443           else
7444             {
7445               /* Advance to the next bigger node.  */
7446               if (elt->right)
7447                 elt = elt->right;
7448               else
7449                 {
7450                   /* We have reached the biggest node in a subtree.  Find
7451                      the parent of it, which is the next bigger node.  */
7452                   while (elt->parent && elt->parent->right == elt)
7453                     elt = elt->parent;
7454                   elt = elt->parent;
7455                   if (elt
7456                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7457                                            bit_position (elt->purpose))))
7458                     {
7459                       next = elt->purpose;
7460                       break;
7461                     }
7462                 }
7463             }
7464         }
7465     }
7466
7467   /* Ordinarily return, but not if we want to output all
7468      and there are elements left.  */
7469   if (!(all && next != 0))
7470     return;
7471
7472   /* If it's not incremental, just skip over the gap, so that after
7473      jumping to retry we will output the next successive element.  */
7474   if (TREE_CODE (constructor_type) == RECORD_TYPE
7475       || TREE_CODE (constructor_type) == UNION_TYPE)
7476     constructor_unfilled_fields = next;
7477   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7478     constructor_unfilled_index = next;
7479
7480   /* ELT now points to the node in the pending tree with the next
7481      initializer to output.  */
7482   goto retry;
7483 }
7484 \f
7485 /* Add one non-braced element to the current constructor level.
7486    This adjusts the current position within the constructor's type.
7487    This may also start or terminate implicit levels
7488    to handle a partly-braced initializer.
7489
7490    Once this has found the correct level for the new element,
7491    it calls output_init_element.
7492
7493    IMPLICIT is true if value comes from pop_init_level (1),
7494    the new initializer has been merged with the existing one
7495    and thus no warnings should be emitted about overriding an
7496    existing initializer.  */
7497
7498 void
7499 process_init_element (struct c_expr value, bool implicit)
7500 {
7501   tree orig_value = value.value;
7502   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7503   bool strict_string = value.original_code == STRING_CST;
7504
7505   designator_depth = 0;
7506   designator_erroneous = 0;
7507
7508   /* Handle superfluous braces around string cst as in
7509      char x[] = {"foo"}; */
7510   if (string_flag
7511       && constructor_type
7512       && TREE_CODE (constructor_type) == ARRAY_TYPE
7513       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7514       && integer_zerop (constructor_unfilled_index))
7515     {
7516       if (constructor_stack->replacement_value.value)
7517         error_init ("excess elements in char array initializer");
7518       constructor_stack->replacement_value = value;
7519       return;
7520     }
7521
7522   if (constructor_stack->replacement_value.value != 0)
7523     {
7524       error_init ("excess elements in struct initializer");
7525       return;
7526     }
7527
7528   /* Ignore elements of a brace group if it is entirely superfluous
7529      and has already been diagnosed.  */
7530   if (constructor_type == 0)
7531     return;
7532
7533   /* If we've exhausted any levels that didn't have braces,
7534      pop them now.  */
7535   while (constructor_stack->implicit)
7536     {
7537       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7538            || TREE_CODE (constructor_type) == UNION_TYPE)
7539           && constructor_fields == 0)
7540         process_init_element (pop_init_level (1), true);
7541       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
7542                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
7543                && (constructor_max_index == 0
7544                    || tree_int_cst_lt (constructor_max_index,
7545                                        constructor_index)))
7546         process_init_element (pop_init_level (1), true);
7547       else
7548         break;
7549     }
7550
7551   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7552   if (constructor_range_stack)
7553     {
7554       /* If value is a compound literal and we'll be just using its
7555          content, don't put it into a SAVE_EXPR.  */
7556       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7557           || !require_constant_value
7558           || flag_isoc99)
7559         {
7560           tree semantic_type = NULL_TREE;
7561           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7562             {
7563               semantic_type = TREE_TYPE (value.value);
7564               value.value = TREE_OPERAND (value.value, 0);
7565             }
7566           value.value = c_save_expr (value.value);
7567           if (semantic_type)
7568             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7569                                   value.value);
7570         }
7571     }
7572
7573   while (1)
7574     {
7575       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7576         {
7577           tree fieldtype;
7578           enum tree_code fieldcode;
7579
7580           if (constructor_fields == 0)
7581             {
7582               pedwarn_init (input_location, 0,
7583                             "excess elements in struct initializer");
7584               break;
7585             }
7586
7587           fieldtype = TREE_TYPE (constructor_fields);
7588           if (fieldtype != error_mark_node)
7589             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7590           fieldcode = TREE_CODE (fieldtype);
7591
7592           /* Error for non-static initialization of a flexible array member.  */
7593           if (fieldcode == ARRAY_TYPE
7594               && !require_constant_value
7595               && TYPE_SIZE (fieldtype) == NULL_TREE
7596               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7597             {
7598               error_init ("non-static initialization of a flexible array member");
7599               break;
7600             }
7601
7602           /* Accept a string constant to initialize a subarray.  */
7603           if (value.value != 0
7604               && fieldcode == ARRAY_TYPE
7605               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7606               && string_flag)
7607             value.value = orig_value;
7608           /* Otherwise, if we have come to a subaggregate,
7609              and we don't have an element of its type, push into it.  */
7610           else if (value.value != 0
7611                    && value.value != error_mark_node
7612                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7613                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7614                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7615             {
7616               push_init_level (1);
7617               continue;
7618             }
7619
7620           if (value.value)
7621             {
7622               push_member_name (constructor_fields);
7623               output_init_element (value.value, value.original_type,
7624                                    strict_string, fieldtype,
7625                                    constructor_fields, 1, implicit);
7626               RESTORE_SPELLING_DEPTH (constructor_depth);
7627             }
7628           else
7629             /* Do the bookkeeping for an element that was
7630                directly output as a constructor.  */
7631             {
7632               /* For a record, keep track of end position of last field.  */
7633               if (DECL_SIZE (constructor_fields))
7634                 constructor_bit_index
7635                   = size_binop (PLUS_EXPR,
7636                                 bit_position (constructor_fields),
7637                                 DECL_SIZE (constructor_fields));
7638
7639               /* If the current field was the first one not yet written out,
7640                  it isn't now, so update.  */
7641               if (constructor_unfilled_fields == constructor_fields)
7642                 {
7643                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7644                   /* Skip any nameless bit fields.  */
7645                   while (constructor_unfilled_fields != 0
7646                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7647                          && DECL_NAME (constructor_unfilled_fields) == 0)
7648                     constructor_unfilled_fields =
7649                       TREE_CHAIN (constructor_unfilled_fields);
7650                 }
7651             }
7652
7653           constructor_fields = TREE_CHAIN (constructor_fields);
7654           /* Skip any nameless bit fields at the beginning.  */
7655           while (constructor_fields != 0
7656                  && DECL_C_BIT_FIELD (constructor_fields)
7657                  && DECL_NAME (constructor_fields) == 0)
7658             constructor_fields = TREE_CHAIN (constructor_fields);
7659         }
7660       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7661         {
7662           tree fieldtype;
7663           enum tree_code fieldcode;
7664
7665           if (constructor_fields == 0)
7666             {
7667               pedwarn_init (input_location, 0,
7668                             "excess elements in union initializer");
7669               break;
7670             }
7671
7672           fieldtype = TREE_TYPE (constructor_fields);
7673           if (fieldtype != error_mark_node)
7674             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7675           fieldcode = TREE_CODE (fieldtype);
7676
7677           /* Warn that traditional C rejects initialization of unions.
7678              We skip the warning if the value is zero.  This is done
7679              under the assumption that the zero initializer in user
7680              code appears conditioned on e.g. __STDC__ to avoid
7681              "missing initializer" warnings and relies on default
7682              initialization to zero in the traditional C case.
7683              We also skip the warning if the initializer is designated,
7684              again on the assumption that this must be conditional on
7685              __STDC__ anyway (and we've already complained about the
7686              member-designator already).  */
7687           if (!in_system_header && !constructor_designated
7688               && !(value.value && (integer_zerop (value.value)
7689                                    || real_zerop (value.value))))
7690             warning (OPT_Wtraditional, "traditional C rejects initialization "
7691                      "of unions");
7692
7693           /* Accept a string constant to initialize a subarray.  */
7694           if (value.value != 0
7695               && fieldcode == ARRAY_TYPE
7696               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7697               && string_flag)
7698             value.value = orig_value;
7699           /* Otherwise, if we have come to a subaggregate,
7700              and we don't have an element of its type, push into it.  */
7701           else if (value.value != 0
7702                    && value.value != error_mark_node
7703                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7704                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7705                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7706             {
7707               push_init_level (1);
7708               continue;
7709             }
7710
7711           if (value.value)
7712             {
7713               push_member_name (constructor_fields);
7714               output_init_element (value.value, value.original_type,
7715                                    strict_string, fieldtype,
7716                                    constructor_fields, 1, implicit);
7717               RESTORE_SPELLING_DEPTH (constructor_depth);
7718             }
7719           else
7720             /* Do the bookkeeping for an element that was
7721                directly output as a constructor.  */
7722             {
7723               constructor_bit_index = DECL_SIZE (constructor_fields);
7724               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7725             }
7726
7727           constructor_fields = 0;
7728         }
7729       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7730         {
7731           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7732           enum tree_code eltcode = TREE_CODE (elttype);
7733
7734           /* Accept a string constant to initialize a subarray.  */
7735           if (value.value != 0
7736               && eltcode == ARRAY_TYPE
7737               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7738               && string_flag)
7739             value.value = orig_value;
7740           /* Otherwise, if we have come to a subaggregate,
7741              and we don't have an element of its type, push into it.  */
7742           else if (value.value != 0
7743                    && value.value != error_mark_node
7744                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7745                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7746                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
7747             {
7748               push_init_level (1);
7749               continue;
7750             }
7751
7752           if (constructor_max_index != 0
7753               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7754                   || integer_all_onesp (constructor_max_index)))
7755             {
7756               pedwarn_init (input_location, 0,
7757                             "excess elements in array initializer");
7758               break;
7759             }
7760
7761           /* Now output the actual element.  */
7762           if (value.value)
7763             {
7764               push_array_bounds (tree_low_cst (constructor_index, 1));
7765               output_init_element (value.value, value.original_type,
7766                                    strict_string, elttype,
7767                                    constructor_index, 1, implicit);
7768               RESTORE_SPELLING_DEPTH (constructor_depth);
7769             }
7770
7771           constructor_index
7772             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7773
7774           if (!value.value)
7775             /* If we are doing the bookkeeping for an element that was
7776                directly output as a constructor, we must update
7777                constructor_unfilled_index.  */
7778             constructor_unfilled_index = constructor_index;
7779         }
7780       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7781         {
7782           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7783
7784          /* Do a basic check of initializer size.  Note that vectors
7785             always have a fixed size derived from their type.  */
7786           if (tree_int_cst_lt (constructor_max_index, constructor_index))
7787             {
7788               pedwarn_init (input_location, 0,
7789                             "excess elements in vector initializer");
7790               break;
7791             }
7792
7793           /* Now output the actual element.  */
7794           if (value.value)
7795             {
7796               if (TREE_CODE (value.value) == VECTOR_CST)
7797                 elttype = TYPE_MAIN_VARIANT (constructor_type);
7798               output_init_element (value.value, value.original_type,
7799                                    strict_string, elttype,
7800                                    constructor_index, 1, implicit);
7801             }
7802
7803           constructor_index
7804             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
7805
7806           if (!value.value)
7807             /* If we are doing the bookkeeping for an element that was
7808                directly output as a constructor, we must update
7809                constructor_unfilled_index.  */
7810             constructor_unfilled_index = constructor_index;
7811         }
7812
7813       /* Handle the sole element allowed in a braced initializer
7814          for a scalar variable.  */
7815       else if (constructor_type != error_mark_node
7816                && constructor_fields == 0)
7817         {
7818           pedwarn_init (input_location, 0,
7819                         "excess elements in scalar initializer");
7820           break;
7821         }
7822       else
7823         {
7824           if (value.value)
7825             output_init_element (value.value, value.original_type,
7826                                  strict_string, constructor_type,
7827                                  NULL_TREE, 1, implicit);
7828           constructor_fields = 0;
7829         }
7830
7831       /* Handle range initializers either at this level or anywhere higher
7832          in the designator stack.  */
7833       if (constructor_range_stack)
7834         {
7835           struct constructor_range_stack *p, *range_stack;
7836           int finish = 0;
7837
7838           range_stack = constructor_range_stack;
7839           constructor_range_stack = 0;
7840           while (constructor_stack != range_stack->stack)
7841             {
7842               gcc_assert (constructor_stack->implicit);
7843               process_init_element (pop_init_level (1), true);
7844             }
7845           for (p = range_stack;
7846                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
7847                p = p->prev)
7848             {
7849               gcc_assert (constructor_stack->implicit);
7850               process_init_element (pop_init_level (1), true);
7851             }
7852
7853           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
7854           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
7855             finish = 1;
7856
7857           while (1)
7858             {
7859               constructor_index = p->index;
7860               constructor_fields = p->fields;
7861               if (finish && p->range_end && p->index == p->range_start)
7862                 {
7863                   finish = 0;
7864                   p->prev = 0;
7865                 }
7866               p = p->next;
7867               if (!p)
7868                 break;
7869               push_init_level (2);
7870               p->stack = constructor_stack;
7871               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
7872                 p->index = p->range_start;
7873             }
7874
7875           if (!finish)
7876             constructor_range_stack = range_stack;
7877           continue;
7878         }
7879
7880       break;
7881     }
7882
7883   constructor_range_stack = 0;
7884 }
7885 \f
7886 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
7887    (guaranteed to be 'volatile' or null) and ARGS (represented using
7888    an ASM_EXPR node).  */
7889 tree
7890 build_asm_stmt (tree cv_qualifier, tree args)
7891 {
7892   if (!ASM_VOLATILE_P (args) && cv_qualifier)
7893     ASM_VOLATILE_P (args) = 1;
7894   return add_stmt (args);
7895 }
7896
7897 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
7898    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
7899    SIMPLE indicates whether there was anything at all after the
7900    string in the asm expression -- asm("blah") and asm("blah" : )
7901    are subtly different.  We use a ASM_EXPR node to represent this.  */
7902 tree
7903 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
7904                 tree clobbers, bool simple)
7905 {
7906   tree tail;
7907   tree args;
7908   int i;
7909   const char *constraint;
7910   const char **oconstraints;
7911   bool allows_mem, allows_reg, is_inout;
7912   int ninputs, noutputs;
7913
7914   ninputs = list_length (inputs);
7915   noutputs = list_length (outputs);
7916   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7917
7918   string = resolve_asm_operand_names (string, outputs, inputs);
7919
7920   /* Remove output conversions that change the type but not the mode.  */
7921   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7922     {
7923       tree output = TREE_VALUE (tail);
7924
7925       /* ??? Really, this should not be here.  Users should be using a
7926          proper lvalue, dammit.  But there's a long history of using casts
7927          in the output operands.  In cases like longlong.h, this becomes a
7928          primitive form of typechecking -- if the cast can be removed, then
7929          the output operand had a type of the proper width; otherwise we'll
7930          get an error.  Gross, but ...  */
7931       STRIP_NOPS (output);
7932
7933       if (!lvalue_or_else (output, lv_asm))
7934         output = error_mark_node;
7935
7936       if (output != error_mark_node
7937           && (TREE_READONLY (output)
7938               || TYPE_READONLY (TREE_TYPE (output))
7939               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7940                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7941                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7942         readonly_error (output, lv_asm);
7943
7944       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7945       oconstraints[i] = constraint;
7946
7947       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7948                                    &allows_mem, &allows_reg, &is_inout))
7949         {
7950           /* If the operand is going to end up in memory,
7951              mark it addressable.  */
7952           if (!allows_reg && !c_mark_addressable (output))
7953             output = error_mark_node;
7954         }
7955       else
7956         output = error_mark_node;
7957
7958       TREE_VALUE (tail) = output;
7959     }
7960
7961   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7962     {
7963       tree input;
7964
7965       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7966       input = TREE_VALUE (tail);
7967
7968       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7969                                   oconstraints, &allows_mem, &allows_reg))
7970         {
7971           /* If the operand is going to end up in memory,
7972              mark it addressable.  */
7973           if (!allows_reg && allows_mem)
7974             {
7975               /* Strip the nops as we allow this case.  FIXME, this really
7976                  should be rejected or made deprecated.  */
7977               STRIP_NOPS (input);
7978               if (!c_mark_addressable (input))
7979                 input = error_mark_node;
7980           }
7981         }
7982       else
7983         input = error_mark_node;
7984
7985       TREE_VALUE (tail) = input;
7986     }
7987
7988   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers);
7989
7990   /* asm statements without outputs, including simple ones, are treated
7991      as volatile.  */
7992   ASM_INPUT_P (args) = simple;
7993   ASM_VOLATILE_P (args) = (noutputs == 0);
7994
7995   return args;
7996 }
7997 \f
7998 /* Generate a goto statement to LABEL.  LOC is the location of the
7999    GOTO.  */
8000
8001 tree
8002 c_finish_goto_label (location_t loc, tree label)
8003 {
8004   tree decl = lookup_label_for_goto (loc, label);
8005   if (!decl)
8006     return NULL_TREE;
8007   TREE_USED (decl) = 1;
8008   {
8009     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8010     SET_EXPR_LOCATION (t, loc);
8011     return add_stmt (t);
8012   }
8013 }
8014
8015 /* Generate a computed goto statement to EXPR.  LOC is the location of
8016    the GOTO.  */
8017
8018 tree
8019 c_finish_goto_ptr (location_t loc, tree expr)
8020 {
8021   tree t;
8022   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8023   expr = c_fully_fold (expr, false, NULL);
8024   expr = convert (ptr_type_node, expr);
8025   t = build1 (GOTO_EXPR, void_type_node, expr);
8026   SET_EXPR_LOCATION (t, loc);
8027   return add_stmt (t);
8028 }
8029
8030 /* Generate a C `return' statement.  RETVAL is the expression for what
8031    to return, or a null pointer for `return;' with no value.  LOC is
8032    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8033    is the original type of RETVAL.  */
8034
8035 tree
8036 c_finish_return (location_t loc, tree retval, tree origtype)
8037 {
8038   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8039   bool no_warning = false;
8040   bool npc = false;
8041
8042   if (TREE_THIS_VOLATILE (current_function_decl))
8043     warning_at (loc, 0,
8044                 "function declared %<noreturn%> has a %<return%> statement");
8045
8046   if (retval)
8047     {
8048       tree semantic_type = NULL_TREE;
8049       npc = null_pointer_constant_p (retval);
8050       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8051         {
8052           semantic_type = TREE_TYPE (retval);
8053           retval = TREE_OPERAND (retval, 0);
8054         }
8055       retval = c_fully_fold (retval, false, NULL);
8056       if (semantic_type)
8057         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8058     }
8059
8060   if (!retval)
8061     {
8062       current_function_returns_null = 1;
8063       if ((warn_return_type || flag_isoc99)
8064           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8065         {
8066           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8067                        "%<return%> with no value, in "
8068                        "function returning non-void");
8069           no_warning = true;
8070         }
8071     }
8072   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8073     {
8074       current_function_returns_null = 1;
8075       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8076         pedwarn (loc, 0,
8077                  "%<return%> with a value, in function returning void");
8078       else
8079         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8080                  "%<return%> with expression, in function returning void");
8081     }
8082   else
8083     {
8084       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8085                                        ic_return,
8086                                        npc, NULL_TREE, NULL_TREE, 0);
8087       tree res = DECL_RESULT (current_function_decl);
8088       tree inner;
8089
8090       current_function_returns_value = 1;
8091       if (t == error_mark_node)
8092         return NULL_TREE;
8093
8094       inner = t = convert (TREE_TYPE (res), t);
8095
8096       /* Strip any conversions, additions, and subtractions, and see if
8097          we are returning the address of a local variable.  Warn if so.  */
8098       while (1)
8099         {
8100           switch (TREE_CODE (inner))
8101             {
8102             CASE_CONVERT:
8103             case NON_LVALUE_EXPR:
8104             case PLUS_EXPR:
8105             case POINTER_PLUS_EXPR:
8106               inner = TREE_OPERAND (inner, 0);
8107               continue;
8108
8109             case MINUS_EXPR:
8110               /* If the second operand of the MINUS_EXPR has a pointer
8111                  type (or is converted from it), this may be valid, so
8112                  don't give a warning.  */
8113               {
8114                 tree op1 = TREE_OPERAND (inner, 1);
8115
8116                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8117                        && (CONVERT_EXPR_P (op1)
8118                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8119                   op1 = TREE_OPERAND (op1, 0);
8120
8121                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8122                   break;
8123
8124                 inner = TREE_OPERAND (inner, 0);
8125                 continue;
8126               }
8127
8128             case ADDR_EXPR:
8129               inner = TREE_OPERAND (inner, 0);
8130
8131               while (REFERENCE_CLASS_P (inner)
8132                      && TREE_CODE (inner) != INDIRECT_REF)
8133                 inner = TREE_OPERAND (inner, 0);
8134
8135               if (DECL_P (inner)
8136                   && !DECL_EXTERNAL (inner)
8137                   && !TREE_STATIC (inner)
8138                   && DECL_CONTEXT (inner) == current_function_decl)
8139                 warning_at (loc,
8140                             0, "function returns address of local variable");
8141               break;
8142
8143             default:
8144               break;
8145             }
8146
8147           break;
8148         }
8149
8150       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8151       SET_EXPR_LOCATION (retval, loc);
8152
8153       if (warn_sequence_point)
8154         verify_sequence_points (retval);
8155     }
8156
8157   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8158   TREE_NO_WARNING (ret_stmt) |= no_warning;
8159   return add_stmt (ret_stmt);
8160 }
8161 \f
8162 struct c_switch {
8163   /* The SWITCH_EXPR being built.  */
8164   tree switch_expr;
8165
8166   /* The original type of the testing expression, i.e. before the
8167      default conversion is applied.  */
8168   tree orig_type;
8169
8170   /* A splay-tree mapping the low element of a case range to the high
8171      element, or NULL_TREE if there is no high element.  Used to
8172      determine whether or not a new case label duplicates an old case
8173      label.  We need a tree, rather than simply a hash table, because
8174      of the GNU case range extension.  */
8175   splay_tree cases;
8176
8177   /* The bindings at the point of the switch.  This is used for
8178      warnings crossing decls when branching to a case label.  */
8179   struct c_spot_bindings *bindings;
8180
8181   /* The next node on the stack.  */
8182   struct c_switch *next;
8183 };
8184
8185 /* A stack of the currently active switch statements.  The innermost
8186    switch statement is on the top of the stack.  There is no need to
8187    mark the stack for garbage collection because it is only active
8188    during the processing of the body of a function, and we never
8189    collect at that point.  */
8190
8191 struct c_switch *c_switch_stack;
8192
8193 /* Start a C switch statement, testing expression EXP.  Return the new
8194    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8195    SWITCH_COND_LOC is the location of the switch's condition.  */
8196
8197 tree
8198 c_start_case (location_t switch_loc,
8199               location_t switch_cond_loc,
8200               tree exp)
8201 {
8202   tree orig_type = error_mark_node;
8203   struct c_switch *cs;
8204
8205   if (exp != error_mark_node)
8206     {
8207       orig_type = TREE_TYPE (exp);
8208
8209       if (!INTEGRAL_TYPE_P (orig_type))
8210         {
8211           if (orig_type != error_mark_node)
8212             {
8213               error_at (switch_cond_loc, "switch quantity not an integer");
8214               orig_type = error_mark_node;
8215             }
8216           exp = integer_zero_node;
8217         }
8218       else
8219         {
8220           tree type = TYPE_MAIN_VARIANT (orig_type);
8221
8222           if (!in_system_header
8223               && (type == long_integer_type_node
8224                   || type == long_unsigned_type_node))
8225             warning_at (switch_cond_loc,
8226                         OPT_Wtraditional, "%<long%> switch expression not "
8227                         "converted to %<int%> in ISO C");
8228
8229           exp = c_fully_fold (exp, false, NULL);
8230           exp = default_conversion (exp);
8231
8232           if (warn_sequence_point)
8233             verify_sequence_points (exp);
8234         }
8235     }
8236
8237   /* Add this new SWITCH_EXPR to the stack.  */
8238   cs = XNEW (struct c_switch);
8239   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8240   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8241   cs->orig_type = orig_type;
8242   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8243   cs->bindings = c_get_switch_bindings ();
8244   cs->next = c_switch_stack;
8245   c_switch_stack = cs;
8246
8247   return add_stmt (cs->switch_expr);
8248 }
8249
8250 /* Process a case label at location LOC.  */
8251
8252 tree
8253 do_case (location_t loc, tree low_value, tree high_value)
8254 {
8255   tree label = NULL_TREE;
8256
8257   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8258     {
8259       low_value = c_fully_fold (low_value, false, NULL);
8260       if (TREE_CODE (low_value) == INTEGER_CST)
8261         pedwarn (input_location, OPT_pedantic,
8262                  "case label is not an integer constant expression");
8263     }
8264
8265   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8266     {
8267       high_value = c_fully_fold (high_value, false, NULL);
8268       if (TREE_CODE (high_value) == INTEGER_CST)
8269         pedwarn (input_location, OPT_pedantic,
8270                  "case label is not an integer constant expression");
8271     }
8272
8273   if (c_switch_stack == NULL)
8274     {
8275       if (low_value)
8276         error_at (loc, "case label not within a switch statement");
8277       else
8278         error_at (loc, "%<default%> label not within a switch statement");
8279       return NULL_TREE;
8280     }
8281
8282   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8283                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8284                                     loc))
8285     return NULL_TREE;
8286
8287   label = c_add_case_label (loc, c_switch_stack->cases,
8288                             SWITCH_COND (c_switch_stack->switch_expr),
8289                             c_switch_stack->orig_type,
8290                             low_value, high_value);
8291   if (label == error_mark_node)
8292     label = NULL_TREE;
8293   return label;
8294 }
8295
8296 /* Finish the switch statement.  */
8297
8298 void
8299 c_finish_case (tree body)
8300 {
8301   struct c_switch *cs = c_switch_stack;
8302   location_t switch_location;
8303
8304   SWITCH_BODY (cs->switch_expr) = body;
8305
8306   /* Emit warnings as needed.  */
8307   switch_location = EXPR_LOCATION (cs->switch_expr);
8308   c_do_switch_warnings (cs->cases, switch_location,
8309                         TREE_TYPE (cs->switch_expr),
8310                         SWITCH_COND (cs->switch_expr));
8311
8312   /* Pop the stack.  */
8313   c_switch_stack = cs->next;
8314   splay_tree_delete (cs->cases);
8315   c_release_switch_bindings (cs->bindings);
8316   XDELETE (cs);
8317 }
8318 \f
8319 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8320    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8321    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8322    statement, and was not surrounded with parenthesis.  */
8323
8324 void
8325 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8326                   tree else_block, bool nested_if)
8327 {
8328   tree stmt;
8329
8330   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8331   if (warn_parentheses && nested_if && else_block == NULL)
8332     {
8333       tree inner_if = then_block;
8334
8335       /* We know from the grammar productions that there is an IF nested
8336          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8337          it might not be exactly THEN_BLOCK, but should be the last
8338          non-container statement within.  */
8339       while (1)
8340         switch (TREE_CODE (inner_if))
8341           {
8342           case COND_EXPR:
8343             goto found;
8344           case BIND_EXPR:
8345             inner_if = BIND_EXPR_BODY (inner_if);
8346             break;
8347           case STATEMENT_LIST:
8348             inner_if = expr_last (then_block);
8349             break;
8350           case TRY_FINALLY_EXPR:
8351           case TRY_CATCH_EXPR:
8352             inner_if = TREE_OPERAND (inner_if, 0);
8353             break;
8354           default:
8355             gcc_unreachable ();
8356           }
8357     found:
8358
8359       if (COND_EXPR_ELSE (inner_if))
8360          warning (OPT_Wparentheses,
8361                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
8362                   &if_locus);
8363     }
8364
8365   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8366   SET_EXPR_LOCATION (stmt, if_locus);
8367   add_stmt (stmt);
8368 }
8369
8370 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8371    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8372    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8373    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8374    the continue label.  Everything is allowed to be NULL.  */
8375
8376 void
8377 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8378                tree blab, tree clab, bool cond_is_first)
8379 {
8380   tree entry = NULL, exit = NULL, t;
8381
8382   /* If the condition is zero don't generate a loop construct.  */
8383   if (cond && integer_zerop (cond))
8384     {
8385       if (cond_is_first)
8386         {
8387           t = build_and_jump (&blab);
8388           SET_EXPR_LOCATION (t, start_locus);
8389           add_stmt (t);
8390         }
8391     }
8392   else
8393     {
8394       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8395
8396       /* If we have an exit condition, then we build an IF with gotos either
8397          out of the loop, or to the top of it.  If there's no exit condition,
8398          then we just build a jump back to the top.  */
8399       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8400
8401       if (cond && !integer_nonzerop (cond))
8402         {
8403           /* Canonicalize the loop condition to the end.  This means
8404              generating a branch to the loop condition.  Reuse the
8405              continue label, if possible.  */
8406           if (cond_is_first)
8407             {
8408               if (incr || !clab)
8409                 {
8410                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8411                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8412                 }
8413               else
8414                 t = build1 (GOTO_EXPR, void_type_node, clab);
8415               SET_EXPR_LOCATION (t, start_locus);
8416               add_stmt (t);
8417             }
8418
8419           t = build_and_jump (&blab);
8420           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
8421           if (cond_is_first)
8422             SET_EXPR_LOCATION (exit, start_locus);
8423           else
8424             SET_EXPR_LOCATION (exit, input_location);
8425         }
8426
8427       add_stmt (top);
8428     }
8429
8430   if (body)
8431     add_stmt (body);
8432   if (clab)
8433     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8434   if (incr)
8435     add_stmt (incr);
8436   if (entry)
8437     add_stmt (entry);
8438   if (exit)
8439     add_stmt (exit);
8440   if (blab)
8441     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8442 }
8443
8444 tree
8445 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
8446 {
8447   bool skip;
8448   tree label = *label_p;
8449
8450   /* In switch statements break is sometimes stylistically used after
8451      a return statement.  This can lead to spurious warnings about
8452      control reaching the end of a non-void function when it is
8453      inlined.  Note that we are calling block_may_fallthru with
8454      language specific tree nodes; this works because
8455      block_may_fallthru returns true when given something it does not
8456      understand.  */
8457   skip = !block_may_fallthru (cur_stmt_list);
8458
8459   if (!label)
8460     {
8461       if (!skip)
8462         *label_p = label = create_artificial_label (loc);
8463     }
8464   else if (TREE_CODE (label) == LABEL_DECL)
8465     ;
8466   else switch (TREE_INT_CST_LOW (label))
8467     {
8468     case 0:
8469       if (is_break)
8470         error_at (loc, "break statement not within loop or switch");
8471       else
8472         error_at (loc, "continue statement not within a loop");
8473       return NULL_TREE;
8474
8475     case 1:
8476       gcc_assert (is_break);
8477       error_at (loc, "break statement used with OpenMP for loop");
8478       return NULL_TREE;
8479
8480     default:
8481       gcc_unreachable ();
8482     }
8483
8484   if (skip)
8485     return NULL_TREE;
8486
8487   if (!is_break)
8488     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8489
8490   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8491 }
8492
8493 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8494
8495 static void
8496 emit_side_effect_warnings (location_t loc, tree expr)
8497 {
8498   if (expr == error_mark_node)
8499     ;
8500   else if (!TREE_SIDE_EFFECTS (expr))
8501     {
8502       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8503         warning_at (loc, OPT_Wunused_value, "statement with no effect");
8504     }
8505   else
8506     warn_if_unused_value (expr, loc);
8507 }
8508
8509 /* Process an expression as if it were a complete statement.  Emit
8510    diagnostics, but do not call ADD_STMT.  LOC is the location of the
8511    statement.  */
8512
8513 tree
8514 c_process_expr_stmt (location_t loc, tree expr)
8515 {
8516   if (!expr)
8517     return NULL_TREE;
8518
8519   expr = c_fully_fold (expr, false, NULL);
8520
8521   if (warn_sequence_point)
8522     verify_sequence_points (expr);
8523
8524   if (TREE_TYPE (expr) != error_mark_node
8525       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8526       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8527     error_at (loc, "expression statement has incomplete type");
8528
8529   /* If we're not processing a statement expression, warn about unused values.
8530      Warnings for statement expressions will be emitted later, once we figure
8531      out which is the result.  */
8532   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8533       && warn_unused_value)
8534     emit_side_effect_warnings (loc, expr);
8535
8536   /* If the expression is not of a type to which we cannot assign a line
8537      number, wrap the thing in a no-op NOP_EXPR.  */
8538   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8539     {
8540       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8541       SET_EXPR_LOCATION (expr, loc);
8542     }
8543
8544   return expr;
8545 }
8546
8547 /* Emit an expression as a statement.  LOC is the location of the
8548    expression.  */
8549
8550 tree
8551 c_finish_expr_stmt (location_t loc, tree expr)
8552 {
8553   if (expr)
8554     return add_stmt (c_process_expr_stmt (loc, expr));
8555   else
8556     return NULL;
8557 }
8558
8559 /* Do the opposite and emit a statement as an expression.  To begin,
8560    create a new binding level and return it.  */
8561
8562 tree
8563 c_begin_stmt_expr (void)
8564 {
8565   tree ret;
8566
8567   /* We must force a BLOCK for this level so that, if it is not expanded
8568      later, there is a way to turn off the entire subtree of blocks that
8569      are contained in it.  */
8570   keep_next_level ();
8571   ret = c_begin_compound_stmt (true);
8572
8573   c_bindings_start_stmt_expr (c_switch_stack == NULL
8574                               ? NULL
8575                               : c_switch_stack->bindings);
8576
8577   /* Mark the current statement list as belonging to a statement list.  */
8578   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8579
8580   return ret;
8581 }
8582
8583 /* LOC is the location of the compound statement to which this body
8584    belongs.  */
8585
8586 tree
8587 c_finish_stmt_expr (location_t loc, tree body)
8588 {
8589   tree last, type, tmp, val;
8590   tree *last_p;
8591
8592   body = c_end_compound_stmt (loc, body, true);
8593
8594   c_bindings_end_stmt_expr (c_switch_stack == NULL
8595                             ? NULL
8596                             : c_switch_stack->bindings);
8597
8598   /* Locate the last statement in BODY.  See c_end_compound_stmt
8599      about always returning a BIND_EXPR.  */
8600   last_p = &BIND_EXPR_BODY (body);
8601   last = BIND_EXPR_BODY (body);
8602
8603  continue_searching:
8604   if (TREE_CODE (last) == STATEMENT_LIST)
8605     {
8606       tree_stmt_iterator i;
8607
8608       /* This can happen with degenerate cases like ({ }).  No value.  */
8609       if (!TREE_SIDE_EFFECTS (last))
8610         return body;
8611
8612       /* If we're supposed to generate side effects warnings, process
8613          all of the statements except the last.  */
8614       if (warn_unused_value)
8615         {
8616           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8617             {
8618               location_t tloc;
8619               tree t = tsi_stmt (i);
8620
8621               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
8622               emit_side_effect_warnings (tloc, t);
8623             }
8624         }
8625       else
8626         i = tsi_last (last);
8627       last_p = tsi_stmt_ptr (i);
8628       last = *last_p;
8629     }
8630
8631   /* If the end of the list is exception related, then the list was split
8632      by a call to push_cleanup.  Continue searching.  */
8633   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8634       || TREE_CODE (last) == TRY_CATCH_EXPR)
8635     {
8636       last_p = &TREE_OPERAND (last, 0);
8637       last = *last_p;
8638       goto continue_searching;
8639     }
8640
8641   /* In the case that the BIND_EXPR is not necessary, return the
8642      expression out from inside it.  */
8643   if (last == error_mark_node
8644       || (last == BIND_EXPR_BODY (body)
8645           && BIND_EXPR_VARS (body) == NULL))
8646     {
8647       /* Even if this looks constant, do not allow it in a constant
8648          expression.  */
8649       last = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (last), NULL_TREE, last);
8650       C_MAYBE_CONST_EXPR_NON_CONST (last) = 1;
8651       /* Do not warn if the return value of a statement expression is
8652          unused.  */
8653       TREE_NO_WARNING (last) = 1;
8654       return last;
8655     }
8656
8657   /* Extract the type of said expression.  */
8658   type = TREE_TYPE (last);
8659
8660   /* If we're not returning a value at all, then the BIND_EXPR that
8661      we already have is a fine expression to return.  */
8662   if (!type || VOID_TYPE_P (type))
8663     return body;
8664
8665   /* Now that we've located the expression containing the value, it seems
8666      silly to make voidify_wrapper_expr repeat the process.  Create a
8667      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8668   tmp = create_tmp_var_raw (type, NULL);
8669
8670   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8671      tree_expr_nonnegative_p giving up immediately.  */
8672   val = last;
8673   if (TREE_CODE (val) == NOP_EXPR
8674       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8675     val = TREE_OPERAND (val, 0);
8676
8677   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8678   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
8679
8680   {
8681     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8682     SET_EXPR_LOCATION (t, loc);
8683     return t;
8684   }
8685 }
8686 \f
8687 /* Begin and end compound statements.  This is as simple as pushing
8688    and popping new statement lists from the tree.  */
8689
8690 tree
8691 c_begin_compound_stmt (bool do_scope)
8692 {
8693   tree stmt = push_stmt_list ();
8694   if (do_scope)
8695     push_scope ();
8696   return stmt;
8697 }
8698
8699 /* End a compound statement.  STMT is the statement.  LOC is the
8700    location of the compound statement-- this is usually the location
8701    of the opening brace.  */
8702
8703 tree
8704 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
8705 {
8706   tree block = NULL;
8707
8708   if (do_scope)
8709     {
8710       if (c_dialect_objc ())
8711         objc_clear_super_receiver ();
8712       block = pop_scope ();
8713     }
8714
8715   stmt = pop_stmt_list (stmt);
8716   stmt = c_build_bind_expr (loc, block, stmt);
8717
8718   /* If this compound statement is nested immediately inside a statement
8719      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8720      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8721      STATEMENT_LISTs merge, and thus we can lose track of what statement
8722      was really last.  */
8723   if (cur_stmt_list
8724       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8725       && TREE_CODE (stmt) != BIND_EXPR)
8726     {
8727       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8728       TREE_SIDE_EFFECTS (stmt) = 1;
8729       SET_EXPR_LOCATION (stmt, loc);
8730     }
8731
8732   return stmt;
8733 }
8734
8735 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8736    when the current scope is exited.  EH_ONLY is true when this is not
8737    meant to apply to normal control flow transfer.  */
8738
8739 void
8740 push_cleanup (tree decl, tree cleanup, bool eh_only)
8741 {
8742   enum tree_code code;
8743   tree stmt, list;
8744   bool stmt_expr;
8745
8746   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8747   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
8748   add_stmt (stmt);
8749   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8750   list = push_stmt_list ();
8751   TREE_OPERAND (stmt, 0) = list;
8752   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8753 }
8754 \f
8755 /* Build a binary-operation expression without default conversions.
8756    CODE is the kind of expression to build.
8757    LOCATION is the operator's location.
8758    This function differs from `build' in several ways:
8759    the data type of the result is computed and recorded in it,
8760    warnings are generated if arg data types are invalid,
8761    special handling for addition and subtraction of pointers is known,
8762    and some optimization is done (operations on narrow ints
8763    are done in the narrower type when that gives the same result).
8764    Constant folding is also done before the result is returned.
8765
8766    Note that the operands will never have enumeral types, or function
8767    or array types, because either they will have the default conversions
8768    performed or they have both just been converted to some other type in which
8769    the arithmetic is to be done.  */
8770
8771 tree
8772 build_binary_op (location_t location, enum tree_code code,
8773                  tree orig_op0, tree orig_op1, int convert_p)
8774 {
8775   tree type0, type1, orig_type0, orig_type1;
8776   tree eptype;
8777   enum tree_code code0, code1;
8778   tree op0, op1;
8779   tree ret = error_mark_node;
8780   const char *invalid_op_diag;
8781   bool op0_int_operands, op1_int_operands;
8782   bool int_const, int_const_or_overflow, int_operands;
8783
8784   /* Expression code to give to the expression when it is built.
8785      Normally this is CODE, which is what the caller asked for,
8786      but in some special cases we change it.  */
8787   enum tree_code resultcode = code;
8788
8789   /* Data type in which the computation is to be performed.
8790      In the simplest cases this is the common type of the arguments.  */
8791   tree result_type = NULL;
8792
8793   /* When the computation is in excess precision, the type of the
8794      final EXCESS_PRECISION_EXPR.  */
8795   tree real_result_type = NULL;
8796
8797   /* Nonzero means operands have already been type-converted
8798      in whatever way is necessary.
8799      Zero means they need to be converted to RESULT_TYPE.  */
8800   int converted = 0;
8801
8802   /* Nonzero means create the expression with this type, rather than
8803      RESULT_TYPE.  */
8804   tree build_type = 0;
8805
8806   /* Nonzero means after finally constructing the expression
8807      convert it to this type.  */
8808   tree final_type = 0;
8809
8810   /* Nonzero if this is an operation like MIN or MAX which can
8811      safely be computed in short if both args are promoted shorts.
8812      Also implies COMMON.
8813      -1 indicates a bitwise operation; this makes a difference
8814      in the exact conditions for when it is safe to do the operation
8815      in a narrower mode.  */
8816   int shorten = 0;
8817
8818   /* Nonzero if this is a comparison operation;
8819      if both args are promoted shorts, compare the original shorts.
8820      Also implies COMMON.  */
8821   int short_compare = 0;
8822
8823   /* Nonzero if this is a right-shift operation, which can be computed on the
8824      original short and then promoted if the operand is a promoted short.  */
8825   int short_shift = 0;
8826
8827   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8828   int common = 0;
8829
8830   /* True means types are compatible as far as ObjC is concerned.  */
8831   bool objc_ok;
8832
8833   /* True means this is an arithmetic operation that may need excess
8834      precision.  */
8835   bool may_need_excess_precision;
8836
8837   if (location == UNKNOWN_LOCATION)
8838     location = input_location;
8839
8840   op0 = orig_op0;
8841   op1 = orig_op1;
8842
8843   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
8844   if (op0_int_operands)
8845     op0 = remove_c_maybe_const_expr (op0);
8846   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
8847   if (op1_int_operands)
8848     op1 = remove_c_maybe_const_expr (op1);
8849   int_operands = (op0_int_operands && op1_int_operands);
8850   if (int_operands)
8851     {
8852       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
8853                                && TREE_CODE (orig_op1) == INTEGER_CST);
8854       int_const = (int_const_or_overflow
8855                    && !TREE_OVERFLOW (orig_op0)
8856                    && !TREE_OVERFLOW (orig_op1));
8857     }
8858   else
8859     int_const = int_const_or_overflow = false;
8860
8861   if (convert_p)
8862     {
8863       op0 = default_conversion (op0);
8864       op1 = default_conversion (op1);
8865     }
8866
8867   orig_type0 = type0 = TREE_TYPE (op0);
8868   orig_type1 = type1 = TREE_TYPE (op1);
8869
8870   /* The expression codes of the data types of the arguments tell us
8871      whether the arguments are integers, floating, pointers, etc.  */
8872   code0 = TREE_CODE (type0);
8873   code1 = TREE_CODE (type1);
8874
8875   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8876   STRIP_TYPE_NOPS (op0);
8877   STRIP_TYPE_NOPS (op1);
8878
8879   /* If an error was already reported for one of the arguments,
8880      avoid reporting another error.  */
8881
8882   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8883     return error_mark_node;
8884
8885   if ((invalid_op_diag
8886        = targetm.invalid_binary_op (code, type0, type1)))
8887     {
8888       error_at (location, invalid_op_diag);
8889       return error_mark_node;
8890     }
8891
8892   switch (code)
8893     {
8894     case PLUS_EXPR:
8895     case MINUS_EXPR:
8896     case MULT_EXPR:
8897     case TRUNC_DIV_EXPR:
8898     case CEIL_DIV_EXPR:
8899     case FLOOR_DIV_EXPR:
8900     case ROUND_DIV_EXPR:
8901     case EXACT_DIV_EXPR:
8902       may_need_excess_precision = true;
8903       break;
8904     default:
8905       may_need_excess_precision = false;
8906       break;
8907     }
8908   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
8909     {
8910       op0 = TREE_OPERAND (op0, 0);
8911       type0 = TREE_TYPE (op0);
8912     }
8913   else if (may_need_excess_precision
8914            && (eptype = excess_precision_type (type0)) != NULL_TREE)
8915     {
8916       type0 = eptype;
8917       op0 = convert (eptype, op0);
8918     }
8919   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
8920     {
8921       op1 = TREE_OPERAND (op1, 0);
8922       type1 = TREE_TYPE (op1);
8923     }
8924   else if (may_need_excess_precision
8925            && (eptype = excess_precision_type (type1)) != NULL_TREE)
8926     {
8927       type1 = eptype;
8928       op1 = convert (eptype, op1);
8929     }
8930
8931   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8932
8933   switch (code)
8934     {
8935     case PLUS_EXPR:
8936       /* Handle the pointer + int case.  */
8937       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8938         {
8939           ret = pointer_int_sum (PLUS_EXPR, op0, op1);
8940           goto return_build_binary_op;
8941         }
8942       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8943         {
8944           ret = pointer_int_sum (PLUS_EXPR, op1, op0);
8945           goto return_build_binary_op;
8946         }
8947       else
8948         common = 1;
8949       break;
8950
8951     case MINUS_EXPR:
8952       /* Subtraction of two similar pointers.
8953          We must subtract them as integers, then divide by object size.  */
8954       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8955           && comp_target_types (location, type0, type1))
8956         {
8957           ret = pointer_diff (op0, op1);
8958           goto return_build_binary_op;
8959         }
8960       /* Handle pointer minus int.  Just like pointer plus int.  */
8961       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8962         {
8963           ret = pointer_int_sum (MINUS_EXPR, op0, op1);
8964           goto return_build_binary_op;
8965         }
8966       else
8967         common = 1;
8968       break;
8969
8970     case MULT_EXPR:
8971       common = 1;
8972       break;
8973
8974     case TRUNC_DIV_EXPR:
8975     case CEIL_DIV_EXPR:
8976     case FLOOR_DIV_EXPR:
8977     case ROUND_DIV_EXPR:
8978     case EXACT_DIV_EXPR:
8979       warn_for_div_by_zero (location, op1);
8980
8981       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8982            || code0 == FIXED_POINT_TYPE
8983            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8984           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8985               || code1 == FIXED_POINT_TYPE
8986               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8987         {
8988           enum tree_code tcode0 = code0, tcode1 = code1;
8989
8990           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8991             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8992           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8993             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8994
8995           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8996               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8997             resultcode = RDIV_EXPR;
8998           else
8999             /* Although it would be tempting to shorten always here, that
9000                loses on some targets, since the modulo instruction is
9001                undefined if the quotient can't be represented in the
9002                computation mode.  We shorten only if unsigned or if
9003                dividing by something we know != -1.  */
9004             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9005                        || (TREE_CODE (op1) == INTEGER_CST
9006                            && !integer_all_onesp (op1)));
9007           common = 1;
9008         }
9009       break;
9010
9011     case BIT_AND_EXPR:
9012     case BIT_IOR_EXPR:
9013     case BIT_XOR_EXPR:
9014       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9015         shorten = -1;
9016       /* Allow vector types which are not floating point types.   */
9017       else if (code0 == VECTOR_TYPE
9018                && code1 == VECTOR_TYPE
9019                && !VECTOR_FLOAT_TYPE_P (type0)
9020                && !VECTOR_FLOAT_TYPE_P (type1))
9021         common = 1;
9022       break;
9023
9024     case TRUNC_MOD_EXPR:
9025     case FLOOR_MOD_EXPR:
9026       warn_for_div_by_zero (location, op1);
9027
9028       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9029           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9030           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9031         common = 1;
9032       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9033         {
9034           /* Although it would be tempting to shorten always here, that loses
9035              on some targets, since the modulo instruction is undefined if the
9036              quotient can't be represented in the computation mode.  We shorten
9037              only if unsigned or if dividing by something we know != -1.  */
9038           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9039                      || (TREE_CODE (op1) == INTEGER_CST
9040                          && !integer_all_onesp (op1)));
9041           common = 1;
9042         }
9043       break;
9044
9045     case TRUTH_ANDIF_EXPR:
9046     case TRUTH_ORIF_EXPR:
9047     case TRUTH_AND_EXPR:
9048     case TRUTH_OR_EXPR:
9049     case TRUTH_XOR_EXPR:
9050       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9051            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9052            || code0 == FIXED_POINT_TYPE)
9053           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9054               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9055               || code1 == FIXED_POINT_TYPE))
9056         {
9057           /* Result of these operations is always an int,
9058              but that does not mean the operands should be
9059              converted to ints!  */
9060           result_type = integer_type_node;
9061           op0 = c_common_truthvalue_conversion (location, op0);
9062           op1 = c_common_truthvalue_conversion (location, op1);
9063           converted = 1;
9064         }
9065       if (code == TRUTH_ANDIF_EXPR)
9066         {
9067           int_const_or_overflow = (int_operands
9068                                    && TREE_CODE (orig_op0) == INTEGER_CST
9069                                    && (op0 == truthvalue_false_node
9070                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9071           int_const = (int_const_or_overflow
9072                        && !TREE_OVERFLOW (orig_op0)
9073                        && (op0 == truthvalue_false_node
9074                            || !TREE_OVERFLOW (orig_op1)));
9075         }
9076       else if (code == TRUTH_ORIF_EXPR)
9077         {
9078           int_const_or_overflow = (int_operands
9079                                    && TREE_CODE (orig_op0) == INTEGER_CST
9080                                    && (op0 == truthvalue_true_node
9081                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9082           int_const = (int_const_or_overflow
9083                        && !TREE_OVERFLOW (orig_op0)
9084                        && (op0 == truthvalue_true_node
9085                            || !TREE_OVERFLOW (orig_op1)));
9086         }
9087       break;
9088
9089       /* Shift operations: result has same type as first operand;
9090          always convert second operand to int.
9091          Also set SHORT_SHIFT if shifting rightward.  */
9092
9093     case RSHIFT_EXPR:
9094       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9095           && code1 == INTEGER_TYPE)
9096         {
9097           if (TREE_CODE (op1) == INTEGER_CST)
9098             {
9099               if (tree_int_cst_sgn (op1) < 0)
9100                 {
9101                   int_const = false;
9102                   if (c_inhibit_evaluation_warnings == 0)
9103                     warning (0, "right shift count is negative");
9104                 }
9105               else
9106                 {
9107                   if (!integer_zerop (op1))
9108                     short_shift = 1;
9109
9110                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9111                     {
9112                       int_const = false;
9113                       if (c_inhibit_evaluation_warnings == 0)
9114                         warning (0, "right shift count >= width of type");
9115                     }
9116                 }
9117             }
9118
9119           /* Use the type of the value to be shifted.  */
9120           result_type = type0;
9121           /* Convert the shift-count to an integer, regardless of size
9122              of value being shifted.  */
9123           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9124             op1 = convert (integer_type_node, op1);
9125           /* Avoid converting op1 to result_type later.  */
9126           converted = 1;
9127         }
9128       break;
9129
9130     case LSHIFT_EXPR:
9131       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9132           && code1 == INTEGER_TYPE)
9133         {
9134           if (TREE_CODE (op1) == INTEGER_CST)
9135             {
9136               if (tree_int_cst_sgn (op1) < 0)
9137                 {
9138                   int_const = false;
9139                   if (c_inhibit_evaluation_warnings == 0)
9140                     warning (0, "left shift count is negative");
9141                 }
9142
9143               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9144                 {
9145                   int_const = false;
9146                   if (c_inhibit_evaluation_warnings == 0)
9147                     warning (0, "left shift count >= width of type");
9148                 }
9149             }
9150
9151           /* Use the type of the value to be shifted.  */
9152           result_type = type0;
9153           /* Convert the shift-count to an integer, regardless of size
9154              of value being shifted.  */
9155           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9156             op1 = convert (integer_type_node, op1);
9157           /* Avoid converting op1 to result_type later.  */
9158           converted = 1;
9159         }
9160       break;
9161
9162     case EQ_EXPR:
9163     case NE_EXPR:
9164       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9165         warning_at (location,
9166                     OPT_Wfloat_equal,
9167                     "comparing floating point with == or != is unsafe");
9168       /* Result of comparison is always int,
9169          but don't convert the args to int!  */
9170       build_type = integer_type_node;
9171       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9172            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9173           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9174               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9175         short_compare = 1;
9176       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9177         {
9178           tree tt0 = TREE_TYPE (type0);
9179           tree tt1 = TREE_TYPE (type1);
9180           /* Anything compares with void *.  void * compares with anything.
9181              Otherwise, the targets must be compatible
9182              and both must be object or both incomplete.  */
9183           if (comp_target_types (location, type0, type1))
9184             result_type = common_pointer_type (type0, type1);
9185           else if (VOID_TYPE_P (tt0))
9186             {
9187               /* op0 != orig_op0 detects the case of something
9188                  whose value is 0 but which isn't a valid null ptr const.  */
9189               if (pedantic && !null_pointer_constant_p (orig_op0)
9190                   && TREE_CODE (tt1) == FUNCTION_TYPE)
9191                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9192                          "comparison of %<void *%> with function pointer");
9193             }
9194           else if (VOID_TYPE_P (tt1))
9195             {
9196               if (pedantic && !null_pointer_constant_p (orig_op1)
9197                   && TREE_CODE (tt0) == FUNCTION_TYPE)
9198                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9199                          "comparison of %<void *%> with function pointer");
9200             }
9201           else
9202             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9203             if (!objc_ok)
9204               pedwarn (location, 0,
9205                        "comparison of distinct pointer types lacks a cast");
9206
9207           if (result_type == NULL_TREE)
9208             result_type = ptr_type_node;
9209         }
9210       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9211         {
9212           if (TREE_CODE (op0) == ADDR_EXPR
9213               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9214             warning_at (location,
9215                         OPT_Waddress, "the address of %qD will never be NULL",
9216                         TREE_OPERAND (op0, 0));
9217           result_type = type0;
9218         }
9219       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9220         {
9221           if (TREE_CODE (op1) == ADDR_EXPR
9222               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9223             warning_at (location,
9224                         OPT_Waddress, "the address of %qD will never be NULL",
9225                         TREE_OPERAND (op1, 0));
9226           result_type = type1;
9227         }
9228       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9229         {
9230           result_type = type0;
9231           pedwarn (location, 0, "comparison between pointer and integer");
9232         }
9233       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9234         {
9235           result_type = type1;
9236           pedwarn (location, 0, "comparison between pointer and integer");
9237         }
9238       break;
9239
9240     case LE_EXPR:
9241     case GE_EXPR:
9242     case LT_EXPR:
9243     case GT_EXPR:
9244       build_type = integer_type_node;
9245       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9246            || code0 == FIXED_POINT_TYPE)
9247           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9248               || code1 == FIXED_POINT_TYPE))
9249         short_compare = 1;
9250       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9251         {
9252           if (comp_target_types (location, type0, type1))
9253             {
9254               result_type = common_pointer_type (type0, type1);
9255               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9256                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9257                 pedwarn (location, 0,
9258                          "comparison of complete and incomplete pointers");
9259               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9260                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9261                          "ordered comparisons of pointers to functions");
9262             }
9263           else
9264             {
9265               result_type = ptr_type_node;
9266               pedwarn (location, 0,
9267                        "comparison of distinct pointer types lacks a cast");
9268             }
9269         }
9270       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9271         {
9272           result_type = type0;
9273           if (pedantic)
9274             pedwarn (location, OPT_pedantic,
9275                      "ordered comparison of pointer with integer zero");
9276           else if (extra_warnings)
9277             warning_at (location, OPT_Wextra,
9278                      "ordered comparison of pointer with integer zero");
9279         }
9280       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9281         {
9282           result_type = type1;
9283           pedwarn (location, OPT_pedantic,
9284                    "ordered comparison of pointer with integer zero");
9285         }
9286       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9287         {
9288           result_type = type0;
9289           pedwarn (location, 0, "comparison between pointer and integer");
9290         }
9291       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9292         {
9293           result_type = type1;
9294           pedwarn (location, 0, "comparison between pointer and integer");
9295         }
9296       break;
9297
9298     default:
9299       gcc_unreachable ();
9300     }
9301
9302   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9303     return error_mark_node;
9304
9305   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9306       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9307           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9308                                                     TREE_TYPE (type1))))
9309     {
9310       binary_op_error (location, code, type0, type1);
9311       return error_mark_node;
9312     }
9313
9314   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9315        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9316       &&
9317       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9318        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9319     {
9320       bool first_complex = (code0 == COMPLEX_TYPE);
9321       bool second_complex = (code1 == COMPLEX_TYPE);
9322       int none_complex = (!first_complex && !second_complex);
9323
9324       if (shorten || common || short_compare)
9325         {
9326           result_type = c_common_type (type0, type1);
9327           if (result_type == error_mark_node)
9328             return error_mark_node;
9329         }
9330
9331       if (first_complex != second_complex
9332           && (code == PLUS_EXPR
9333               || code == MINUS_EXPR
9334               || code == MULT_EXPR
9335               || (code == TRUNC_DIV_EXPR && first_complex))
9336           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9337           && flag_signed_zeros)
9338         {
9339           /* An operation on mixed real/complex operands must be
9340              handled specially, but the language-independent code can
9341              more easily optimize the plain complex arithmetic if
9342              -fno-signed-zeros.  */
9343           tree real_type = TREE_TYPE (result_type);
9344           tree real, imag;
9345           if (type0 != orig_type0 || type1 != orig_type1)
9346             {
9347               gcc_assert (may_need_excess_precision && common);
9348               real_result_type = c_common_type (orig_type0, orig_type1);
9349             }
9350           if (first_complex)
9351             {
9352               if (TREE_TYPE (op0) != result_type)
9353                 op0 = convert_and_check (result_type, op0);
9354               if (TREE_TYPE (op1) != real_type)
9355                 op1 = convert_and_check (real_type, op1);
9356             }
9357           else
9358             {
9359               if (TREE_TYPE (op0) != real_type)
9360                 op0 = convert_and_check (real_type, op0);
9361               if (TREE_TYPE (op1) != result_type)
9362                 op1 = convert_and_check (result_type, op1);
9363             }
9364           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9365             return error_mark_node;
9366           if (first_complex)
9367             {
9368               op0 = c_save_expr (op0);
9369               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
9370                                      op0, 1);
9371               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
9372                                      op0, 1);
9373               switch (code)
9374                 {
9375                 case MULT_EXPR:
9376                 case TRUNC_DIV_EXPR:
9377                   imag = build2 (resultcode, real_type, imag, op1);
9378                   /* Fall through.  */
9379                 case PLUS_EXPR:
9380                 case MINUS_EXPR:
9381                   real = build2 (resultcode, real_type, real, op1);
9382                   break;
9383                 default:
9384                   gcc_unreachable();
9385                 }
9386             }
9387           else
9388             {
9389               op1 = c_save_expr (op1);
9390               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
9391                                      op1, 1);
9392               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
9393                                      op1, 1);
9394               switch (code)
9395                 {
9396                 case MULT_EXPR:
9397                   imag = build2 (resultcode, real_type, op0, imag);
9398                   /* Fall through.  */
9399                 case PLUS_EXPR:
9400                   real = build2 (resultcode, real_type, op0, real);
9401                   break;
9402                 case MINUS_EXPR:
9403                   real = build2 (resultcode, real_type, op0, real);
9404                   imag = build1 (NEGATE_EXPR, real_type, imag);
9405                   break;
9406                 default:
9407                   gcc_unreachable();
9408                 }
9409             }
9410           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
9411           goto return_build_binary_op;
9412         }
9413
9414       /* For certain operations (which identify themselves by shorten != 0)
9415          if both args were extended from the same smaller type,
9416          do the arithmetic in that type and then extend.
9417
9418          shorten !=0 and !=1 indicates a bitwise operation.
9419          For them, this optimization is safe only if
9420          both args are zero-extended or both are sign-extended.
9421          Otherwise, we might change the result.
9422          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9423          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9424
9425       if (shorten && none_complex)
9426         {
9427           final_type = result_type;
9428           result_type = shorten_binary_op (result_type, op0, op1,
9429                                            shorten == -1);
9430         }
9431
9432       /* Shifts can be shortened if shifting right.  */
9433
9434       if (short_shift)
9435         {
9436           int unsigned_arg;
9437           tree arg0 = get_narrower (op0, &unsigned_arg);
9438
9439           final_type = result_type;
9440
9441           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9442             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9443
9444           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9445               /* We can shorten only if the shift count is less than the
9446                  number of bits in the smaller type size.  */
9447               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9448               /* We cannot drop an unsigned shift after sign-extension.  */
9449               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9450             {
9451               /* Do an unsigned shift if the operand was zero-extended.  */
9452               result_type
9453                 = c_common_signed_or_unsigned_type (unsigned_arg,
9454                                                     TREE_TYPE (arg0));
9455               /* Convert value-to-be-shifted to that type.  */
9456               if (TREE_TYPE (op0) != result_type)
9457                 op0 = convert (result_type, op0);
9458               converted = 1;
9459             }
9460         }
9461
9462       /* Comparison operations are shortened too but differently.
9463          They identify themselves by setting short_compare = 1.  */
9464
9465       if (short_compare)
9466         {
9467           /* Don't write &op0, etc., because that would prevent op0
9468              from being kept in a register.
9469              Instead, make copies of the our local variables and
9470              pass the copies by reference, then copy them back afterward.  */
9471           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9472           enum tree_code xresultcode = resultcode;
9473           tree val
9474             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9475
9476           if (val != 0)
9477             {
9478               ret = val;
9479               goto return_build_binary_op;
9480             }
9481
9482           op0 = xop0, op1 = xop1;
9483           converted = 1;
9484           resultcode = xresultcode;
9485
9486           if (c_inhibit_evaluation_warnings == 0)
9487             {
9488               bool op0_maybe_const = true;
9489               bool op1_maybe_const = true;
9490               tree orig_op0_folded, orig_op1_folded;
9491
9492               if (in_late_binary_op)
9493                 {
9494                   orig_op0_folded = orig_op0;
9495                   orig_op1_folded = orig_op1;
9496                 }
9497               else
9498                 {
9499                   /* Fold for the sake of possible warnings, as in
9500                      build_conditional_expr.  This requires the
9501                      "original" values to be folded, not just op0 and
9502                      op1.  */
9503                   op0 = c_fully_fold (op0, require_constant_value,
9504                                       &op0_maybe_const);
9505                   op1 = c_fully_fold (op1, require_constant_value,
9506                                       &op1_maybe_const);
9507                   orig_op0_folded = c_fully_fold (orig_op0,
9508                                                   require_constant_value,
9509                                                   NULL);
9510                   orig_op1_folded = c_fully_fold (orig_op1,
9511                                                   require_constant_value,
9512                                                   NULL);
9513                 }
9514
9515               if (warn_sign_compare)
9516                 warn_for_sign_compare (location, orig_op0_folded,
9517                                        orig_op1_folded, op0, op1,
9518                                        result_type, resultcode);
9519               if (!in_late_binary_op)
9520                 {
9521                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9522                     {
9523                       op0 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op0),
9524                                     NULL, op0);
9525                       C_MAYBE_CONST_EXPR_NON_CONST (op0) = !op0_maybe_const;
9526                     }
9527                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9528                     {
9529                       op1 = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (op1),
9530                                     NULL, op1);
9531                       C_MAYBE_CONST_EXPR_NON_CONST (op1) = !op1_maybe_const;
9532                     }
9533                 }
9534             }
9535         }
9536     }
9537
9538   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9539      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9540      Then the expression will be built.
9541      It will be given type FINAL_TYPE if that is nonzero;
9542      otherwise, it will be given type RESULT_TYPE.  */
9543
9544   if (!result_type)
9545     {
9546       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9547       return error_mark_node;
9548     }
9549
9550   if (!converted)
9551     {
9552       if (TREE_TYPE (op0) != result_type)
9553         op0 = convert_and_check (result_type, op0);
9554       if (TREE_TYPE (op1) != result_type)
9555         op1 = convert_and_check (result_type, op1);
9556
9557       /* This can happen if one operand has a vector type, and the other
9558          has a different type.  */
9559       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9560         return error_mark_node;
9561     }
9562
9563   if (build_type == NULL_TREE)
9564     {
9565       build_type = result_type;
9566       if (type0 != orig_type0 || type1 != orig_type1)
9567         {
9568           gcc_assert (may_need_excess_precision && common);
9569           real_result_type = c_common_type (orig_type0, orig_type1);
9570         }
9571     }
9572
9573   /* Treat expressions in initializers specially as they can't trap.  */
9574   if (int_const_or_overflow)
9575     ret = (require_constant_value
9576            ? fold_build2_initializer (resultcode, build_type, op0, op1)
9577            : fold_build2 (resultcode, build_type, op0, op1));
9578   else
9579     ret = build2 (resultcode, build_type, op0, op1);
9580   if (final_type != 0)
9581     ret = convert (final_type, ret);
9582
9583  return_build_binary_op:
9584   gcc_assert (ret != error_mark_node);
9585   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9586     ret = (int_operands
9587            ? note_integer_operands (ret)
9588            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9589   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9590            && !in_late_binary_op)
9591     ret = note_integer_operands (ret);
9592   if (real_result_type)
9593     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9594   protected_set_expr_location (ret, location);
9595   return ret;
9596 }
9597
9598
9599 /* Convert EXPR to be a truth-value, validating its type for this
9600    purpose.  LOCATION is the source location for the expression.  */
9601
9602 tree
9603 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9604 {
9605   bool int_const, int_operands;
9606
9607   switch (TREE_CODE (TREE_TYPE (expr)))
9608     {
9609     case ARRAY_TYPE:
9610       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9611       return error_mark_node;
9612
9613     case RECORD_TYPE:
9614       error_at (location, "used struct type value where scalar is required");
9615       return error_mark_node;
9616
9617     case UNION_TYPE:
9618       error_at (location, "used union type value where scalar is required");
9619       return error_mark_node;
9620
9621     case FUNCTION_TYPE:
9622       gcc_unreachable ();
9623
9624     default:
9625       break;
9626     }
9627
9628   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9629   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9630   if (int_operands)
9631     expr = remove_c_maybe_const_expr (expr);
9632
9633   /* ??? Should we also give an error for void and vectors rather than
9634      leaving those to give errors later?  */
9635   expr = c_common_truthvalue_conversion (location, expr);
9636
9637   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9638     {
9639       if (TREE_OVERFLOW (expr))
9640         return expr;
9641       else
9642         return note_integer_operands (expr);
9643     }
9644   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9645     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9646   return expr;
9647 }
9648 \f
9649
9650 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9651    required.  */
9652
9653 tree
9654 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9655 {
9656   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9657     {
9658       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9659       /* Executing a compound literal inside a function reinitializes
9660          it.  */
9661       if (!TREE_STATIC (decl))
9662         *se = true;
9663       return decl;
9664     }
9665   else
9666     return expr;
9667 }
9668 \f
9669 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9670
9671 tree
9672 c_begin_omp_parallel (void)
9673 {
9674   tree block;
9675
9676   keep_next_level ();
9677   block = c_begin_compound_stmt (true);
9678
9679   return block;
9680 }
9681
9682 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
9683    statement.  LOC is the location of the OMP_PARALLEL.  */
9684
9685 tree
9686 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
9687 {
9688   tree stmt;
9689
9690   block = c_end_compound_stmt (loc, block, true);
9691
9692   stmt = make_node (OMP_PARALLEL);
9693   TREE_TYPE (stmt) = void_type_node;
9694   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9695   OMP_PARALLEL_BODY (stmt) = block;
9696   SET_EXPR_LOCATION (stmt, loc);
9697
9698   return add_stmt (stmt);
9699 }
9700
9701 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9702
9703 tree
9704 c_begin_omp_task (void)
9705 {
9706   tree block;
9707
9708   keep_next_level ();
9709   block = c_begin_compound_stmt (true);
9710
9711   return block;
9712 }
9713
9714 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
9715    statement.  LOC is the location of the #pragma.  */
9716
9717 tree
9718 c_finish_omp_task (location_t loc, tree clauses, tree block)
9719 {
9720   tree stmt;
9721
9722   block = c_end_compound_stmt (loc, block, true);
9723
9724   stmt = make_node (OMP_TASK);
9725   TREE_TYPE (stmt) = void_type_node;
9726   OMP_TASK_CLAUSES (stmt) = clauses;
9727   OMP_TASK_BODY (stmt) = block;
9728   SET_EXPR_LOCATION (stmt, loc);
9729
9730   return add_stmt (stmt);
9731 }
9732
9733 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9734    Remove any elements from the list that are invalid.  */
9735
9736 tree
9737 c_finish_omp_clauses (tree clauses)
9738 {
9739   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9740   tree c, t, *pc = &clauses;
9741   const char *name;
9742
9743   bitmap_obstack_initialize (NULL);
9744   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9745   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9746   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9747
9748   for (pc = &clauses, c = clauses; c ; c = *pc)
9749     {
9750       bool remove = false;
9751       bool need_complete = false;
9752       bool need_implicitly_determined = false;
9753
9754       switch (OMP_CLAUSE_CODE (c))
9755         {
9756         case OMP_CLAUSE_SHARED:
9757           name = "shared";
9758           need_implicitly_determined = true;
9759           goto check_dup_generic;
9760
9761         case OMP_CLAUSE_PRIVATE:
9762           name = "private";
9763           need_complete = true;
9764           need_implicitly_determined = true;
9765           goto check_dup_generic;
9766
9767         case OMP_CLAUSE_REDUCTION:
9768           name = "reduction";
9769           need_implicitly_determined = true;
9770           t = OMP_CLAUSE_DECL (c);
9771           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
9772               || POINTER_TYPE_P (TREE_TYPE (t)))
9773             {
9774               error_at (OMP_CLAUSE_LOCATION (c),
9775                         "%qE has invalid type for %<reduction%>", t);
9776               remove = true;
9777             }
9778           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
9779             {
9780               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
9781               const char *r_name = NULL;
9782
9783               switch (r_code)
9784                 {
9785                 case PLUS_EXPR:
9786                 case MULT_EXPR:
9787                 case MINUS_EXPR:
9788                   break;
9789                 case BIT_AND_EXPR:
9790                   r_name = "&";
9791                   break;
9792                 case BIT_XOR_EXPR:
9793                   r_name = "^";
9794                   break;
9795                 case BIT_IOR_EXPR:
9796                   r_name = "|";
9797                   break;
9798                 case TRUTH_ANDIF_EXPR:
9799                   r_name = "&&";
9800                   break;
9801                 case TRUTH_ORIF_EXPR:
9802                   r_name = "||";
9803                   break;
9804                 default:
9805                   gcc_unreachable ();
9806                 }
9807               if (r_name)
9808                 {
9809                   error_at (OMP_CLAUSE_LOCATION (c),
9810                             "%qE has invalid type for %<reduction(%s)%>",
9811                             t, r_name);
9812                   remove = true;
9813                 }
9814             }
9815           goto check_dup_generic;
9816
9817         case OMP_CLAUSE_COPYPRIVATE:
9818           name = "copyprivate";
9819           goto check_dup_generic;
9820
9821         case OMP_CLAUSE_COPYIN:
9822           name = "copyin";
9823           t = OMP_CLAUSE_DECL (c);
9824           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
9825             {
9826               error_at (OMP_CLAUSE_LOCATION (c),
9827                         "%qE must be %<threadprivate%> for %<copyin%>", t);
9828               remove = true;
9829             }
9830           goto check_dup_generic;
9831
9832         check_dup_generic:
9833           t = OMP_CLAUSE_DECL (c);
9834           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9835             {
9836               error_at (OMP_CLAUSE_LOCATION (c),
9837                         "%qE is not a variable in clause %qs", t, name);
9838               remove = true;
9839             }
9840           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9841                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
9842                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9843             {
9844               error_at (OMP_CLAUSE_LOCATION (c),
9845                         "%qE appears more than once in data clauses", t);
9846               remove = true;
9847             }
9848           else
9849             bitmap_set_bit (&generic_head, DECL_UID (t));
9850           break;
9851
9852         case OMP_CLAUSE_FIRSTPRIVATE:
9853           name = "firstprivate";
9854           t = OMP_CLAUSE_DECL (c);
9855           need_complete = true;
9856           need_implicitly_determined = true;
9857           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9858             {
9859               error_at (OMP_CLAUSE_LOCATION (c),
9860                         "%qE is not a variable in clause %<firstprivate%>", t);
9861               remove = true;
9862             }
9863           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9864                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
9865             {
9866               error_at (OMP_CLAUSE_LOCATION (c),
9867                         "%qE appears more than once in data clauses", t);
9868               remove = true;
9869             }
9870           else
9871             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
9872           break;
9873
9874         case OMP_CLAUSE_LASTPRIVATE:
9875           name = "lastprivate";
9876           t = OMP_CLAUSE_DECL (c);
9877           need_complete = true;
9878           need_implicitly_determined = true;
9879           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
9880             {
9881               error_at (OMP_CLAUSE_LOCATION (c),
9882                         "%qE is not a variable in clause %<lastprivate%>", t);
9883               remove = true;
9884             }
9885           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
9886                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
9887             {
9888               error_at (OMP_CLAUSE_LOCATION (c),
9889                      "%qE appears more than once in data clauses", t);
9890               remove = true;
9891             }
9892           else
9893             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
9894           break;
9895
9896         case OMP_CLAUSE_IF:
9897         case OMP_CLAUSE_NUM_THREADS:
9898         case OMP_CLAUSE_SCHEDULE:
9899         case OMP_CLAUSE_NOWAIT:
9900         case OMP_CLAUSE_ORDERED:
9901         case OMP_CLAUSE_DEFAULT:
9902         case OMP_CLAUSE_UNTIED:
9903         case OMP_CLAUSE_COLLAPSE:
9904           pc = &OMP_CLAUSE_CHAIN (c);
9905           continue;
9906
9907         default:
9908           gcc_unreachable ();
9909         }
9910
9911       if (!remove)
9912         {
9913           t = OMP_CLAUSE_DECL (c);
9914
9915           if (need_complete)
9916             {
9917               t = require_complete_type (t);
9918               if (t == error_mark_node)
9919                 remove = true;
9920             }
9921
9922           if (need_implicitly_determined)
9923             {
9924               const char *share_name = NULL;
9925
9926               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
9927                 share_name = "threadprivate";
9928               else switch (c_omp_predetermined_sharing (t))
9929                 {
9930                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
9931                   break;
9932                 case OMP_CLAUSE_DEFAULT_SHARED:
9933                   share_name = "shared";
9934                   break;
9935                 case OMP_CLAUSE_DEFAULT_PRIVATE:
9936                   share_name = "private";
9937                   break;
9938                 default:
9939                   gcc_unreachable ();
9940                 }
9941               if (share_name)
9942                 {
9943                   error_at (OMP_CLAUSE_LOCATION (c),
9944                             "%qE is predetermined %qs for %qs",
9945                             t, share_name, name);
9946                   remove = true;
9947                 }
9948             }
9949         }
9950
9951       if (remove)
9952         *pc = OMP_CLAUSE_CHAIN (c);
9953       else
9954         pc = &OMP_CLAUSE_CHAIN (c);
9955     }
9956
9957   bitmap_obstack_release (NULL);
9958   return clauses;
9959 }
9960
9961 /* Make a variant type in the proper way for C/C++, propagating qualifiers
9962    down to the element type of an array.  */
9963
9964 tree
9965 c_build_qualified_type (tree type, int type_quals)
9966 {
9967   if (type == error_mark_node)
9968     return type;
9969
9970   if (TREE_CODE (type) == ARRAY_TYPE)
9971     {
9972       tree t;
9973       tree element_type = c_build_qualified_type (TREE_TYPE (type),
9974                                                   type_quals);
9975
9976       /* See if we already have an identically qualified type.  */
9977       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
9978         {
9979           if (TYPE_QUALS (strip_array_types (t)) == type_quals
9980               && TYPE_NAME (t) == TYPE_NAME (type)
9981               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
9982               && attribute_list_equal (TYPE_ATTRIBUTES (t),
9983                                        TYPE_ATTRIBUTES (type)))
9984             break;
9985         }
9986       if (!t)
9987         {
9988           tree domain = TYPE_DOMAIN (type);
9989
9990           t = build_variant_type_copy (type);
9991           TREE_TYPE (t) = element_type;
9992
9993           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
9994               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
9995             SET_TYPE_STRUCTURAL_EQUALITY (t);
9996           else if (TYPE_CANONICAL (element_type) != element_type
9997                    || (domain && TYPE_CANONICAL (domain) != domain))
9998             {
9999               tree unqualified_canon
10000                 = build_array_type (TYPE_CANONICAL (element_type),
10001                                     domain? TYPE_CANONICAL (domain)
10002                                           : NULL_TREE);
10003               TYPE_CANONICAL (t)
10004                 = c_build_qualified_type (unqualified_canon, type_quals);
10005             }
10006           else
10007             TYPE_CANONICAL (t) = t;
10008         }
10009       return t;
10010     }
10011
10012   /* A restrict-qualified pointer type must be a pointer to object or
10013      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10014      REFERENCE_TYPEs, which is appropriate for C++.  */
10015   if ((type_quals & TYPE_QUAL_RESTRICT)
10016       && (!POINTER_TYPE_P (type)
10017           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10018     {
10019       error ("invalid use of %<restrict%>");
10020       type_quals &= ~TYPE_QUAL_RESTRICT;
10021     }
10022
10023   return build_qualified_type (type, type_quals);
10024 }
10025
10026 /* Build a VA_ARG_EXPR for the C parser.  */
10027
10028 tree
10029 c_build_va_arg (location_t loc, tree expr, tree type)
10030 {
10031   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10032     warning_at (loc, OPT_Wc___compat,
10033                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10034   return build_va_arg (loc, expr, type);
10035 }