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
   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_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static bool null_pointer_constant_p (const_tree);
  78 static tree qualify_type (tree, tree);
  79 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  80 static int comp_target_types (tree, tree);
  81 static int function_types_compatible_p (const_tree, const_tree);
  82 static int type_lists_compatible_p (const_tree, const_tree);
  83 static tree decl_constant_value_for_broken_optimization (tree);
  84 static tree lookup_field (tree, tree);
  85 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  86 static tree pointer_diff (tree, tree);
  87 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  88                                     int);
  89 static tree valid_compound_expr_initializer (tree, tree);
  90 static void push_string (const char *);
  91 static void push_member_name (tree);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (int, const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (const_tree, enum lvalue_use);
 106 static int lvalue_p (const_tree);
 107 static void record_maybe_used_decl (tree);
 108 static int comptypes_internal (const_tree, const_tree);
 109 \f
 110 /* Return true if EXP is a null pointer constant, false otherwise.  */
 111
 112 static bool
 113 null_pointer_constant_p (const_tree expr)
 114 {
 115   /* This should really operate on c_expr structures, but they aren't
 116      yet available everywhere required.  */
 117   tree type = TREE_TYPE (expr);
 118   return (TREE_CODE (expr) == INTEGER_CST
 119           && !TREE_OVERFLOW (expr)
 120           && integer_zerop (expr)
 121           && (INTEGRAL_TYPE_P (type)
 122               || (TREE_CODE (type) == POINTER_TYPE
 123                   && VOID_TYPE_P (TREE_TYPE (type))
 124                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 125 }
 126 \f/* This is a cache to hold if two types are compatible or not.  */
 127
 128 struct tagged_tu_seen_cache {
 129   const struct tagged_tu_seen_cache * next;
 130   const_tree t1;
 131   const_tree t2;
 132   /* The return value of tagged_types_tu_compatible_p if we had seen
 133      these two types already.  */
 134   int val;
 135 };
 136
 137 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 138 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 139
 140 /* Do `exp = require_complete_type (exp);' to make sure exp
 141    does not have an incomplete type.  (That includes void types.)  */
 142
 143 tree
 144 require_complete_type (tree value)
 145 {
 146   tree type = TREE_TYPE (value);
 147
 148   if (value == error_mark_node || type == error_mark_node)
 149     return error_mark_node;
 150
 151   /* First, detect a valid value with a complete type.  */
 152   if (COMPLETE_TYPE_P (type))
 153     return value;
 154
 155   c_incomplete_type_error (value, type);
 156   return error_mark_node;
 157 }
 158
 159 /* Print an error message for invalid use of an incomplete type.
 160    VALUE is the expression that was used (or 0 if that isn't known)
 161    and TYPE is the type that was invalid.  */
 162
 163 void
 164 c_incomplete_type_error (const_tree value, const_tree type)
 165 {
 166   const char *type_code_string;
 167
 168   /* Avoid duplicate error message.  */
 169   if (TREE_CODE (type) == ERROR_MARK)
 170     return;
 171
 172   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 173                      || TREE_CODE (value) == PARM_DECL))
 174     error ("%qD has an incomplete type", value);
 175   else
 176     {
 177     retry:
 178       /* We must print an error message.  Be clever about what it says.  */
 179
 180       switch (TREE_CODE (type))
 181         {
 182         case RECORD_TYPE:
 183           type_code_string = "struct";
 184           break;
 185
 186         case UNION_TYPE:
 187           type_code_string = "union";
 188           break;
 189
 190         case ENUMERAL_TYPE:
 191           type_code_string = "enum";
 192           break;
 193
 194         case VOID_TYPE:
 195           error ("invalid use of void expression");
 196           return;
 197
 198         case ARRAY_TYPE:
 199           if (TYPE_DOMAIN (type))
 200             {
 201               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 202                 {
 203                   error ("invalid use of flexible array member");
 204                   return;
 205                 }
 206               type = TREE_TYPE (type);
 207               goto retry;
 208             }
 209           error ("invalid use of array with unspecified bounds");
 210           return;
 211
 212         default:
 213           gcc_unreachable ();
 214         }
 215
 216       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 217         error ("invalid use of undefined type %<%s %E%>",
 218                type_code_string, TYPE_NAME (type));
 219       else
 220         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 221         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 222     }
 223 }
 224
 225 /* Given a type, apply default promotions wrt unnamed function
 226    arguments and return the new type.  */
 227
 228 tree
 229 c_type_promotes_to (tree type)
 230 {
 231   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 232     return double_type_node;
 233
 234   if (c_promoting_integer_type_p (type))
 235     {
 236       /* Preserve unsignedness if not really getting any wider.  */
 237       if (TYPE_UNSIGNED (type)
 238           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 239         return unsigned_type_node;
 240       return integer_type_node;
 241     }
 242
 243   return type;
 244 }
 245
 246 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 247    as well as those of TYPE.  */
 248
 249 static tree
 250 qualify_type (tree type, tree like)
 251 {
 252   return c_build_qualified_type (type,
 253                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 254 }
 255
 256 /* Return true iff the given tree T is a variable length array.  */
 257
 258 bool
 259 c_vla_type_p (const_tree t)
 260 {
 261   if (TREE_CODE (t) == ARRAY_TYPE
 262       && C_TYPE_VARIABLE_SIZE (t))
 263     return true;
 264   return false;
 265 }
 266 \f
 267 /* Return the composite type of two compatible types.
 268
 269    We assume that comptypes has already been done and returned
 270    nonzero; if that isn't so, this may crash.  In particular, we
 271    assume that qualifiers match.  */
 272
 273 tree
 274 composite_type (tree t1, tree t2)
 275 {
 276   enum tree_code code1;
 277   enum tree_code code2;
 278   tree attributes;
 279
 280   /* Save time if the two types are the same.  */
 281
 282   if (t1 == t2) return t1;
 283
 284   /* If one type is nonsense, use the other.  */
 285   if (t1 == error_mark_node)
 286     return t2;
 287   if (t2 == error_mark_node)
 288     return t1;
 289
 290   code1 = TREE_CODE (t1);
 291   code2 = TREE_CODE (t2);
 292
 293   /* Merge the attributes.  */
 294   attributes = targetm.merge_type_attributes (t1, t2);
 295
 296   /* If one is an enumerated type and the other is the compatible
 297      integer type, the composite type might be either of the two
 298      (DR#013 question 3).  For consistency, use the enumerated type as
 299      the composite type.  */
 300
 301   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 302     return t1;
 303   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 304     return t2;
 305
 306   gcc_assert (code1 == code2);
 307
 308   switch (code1)
 309     {
 310     case POINTER_TYPE:
 311       /* For two pointers, do this recursively on the target type.  */
 312       {
 313         tree pointed_to_1 = TREE_TYPE (t1);
 314         tree pointed_to_2 = TREE_TYPE (t2);
 315         tree target = composite_type (pointed_to_1, pointed_to_2);
 316         t1 = build_pointer_type (target);
 317         t1 = build_type_attribute_variant (t1, attributes);
 318         return qualify_type (t1, t2);
 319       }
 320
 321     case ARRAY_TYPE:
 322       {
 323         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 324         int quals;
 325         tree unqual_elt;
 326         tree d1 = TYPE_DOMAIN (t1);
 327         tree d2 = TYPE_DOMAIN (t2);
 328         bool d1_variable, d2_variable;
 329         bool d1_zero, d2_zero;
 330
 331         /* We should not have any type quals on arrays at all.  */
 332         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 333
 334         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 335         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 336
 337         d1_variable = (!d1_zero
 338                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 339                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 340         d2_variable = (!d2_zero
 341                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 342                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 343         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 344         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 345
 346         /* Save space: see if the result is identical to one of the args.  */
 347         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 348             && (d2_variable || d2_zero || !d1_variable))
 349           return build_type_attribute_variant (t1, attributes);
 350         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 351             && (d1_variable || d1_zero || !d2_variable))
 352           return build_type_attribute_variant (t2, attributes);
 353
 354         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 355           return build_type_attribute_variant (t1, attributes);
 356         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 357           return build_type_attribute_variant (t2, attributes);
 358
 359         /* Merge the element types, and have a size if either arg has
 360            one.  We may have qualifiers on the element types.  To set
 361            up TYPE_MAIN_VARIANT correctly, we need to form the
 362            composite of the unqualified types and add the qualifiers
 363            back at the end.  */
 364         quals = TYPE_QUALS (strip_array_types (elt));
 365         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 366         t1 = build_array_type (unqual_elt,
 367                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 368                                              && (d2_variable
 369                                                  || d2_zero
 370                                                  || !d1_variable))
 371                                             ? t1
 372                                             : t2));
 373         t1 = c_build_qualified_type (t1, quals);
 374         return build_type_attribute_variant (t1, attributes);
 375       }
 376
 377     case ENUMERAL_TYPE:
 378     case RECORD_TYPE:
 379     case UNION_TYPE:
 380       if (attributes != NULL)
 381         {
 382           /* Try harder not to create a new aggregate type.  */
 383           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 384             return t1;
 385           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 386             return t2;
 387         }
 388       return build_type_attribute_variant (t1, attributes);
 389
 390     case FUNCTION_TYPE:
 391       /* Function types: prefer the one that specified arg types.
 392          If both do, merge the arg types.  Also merge the return types.  */
 393       {
 394         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 395         tree p1 = TYPE_ARG_TYPES (t1);
 396         tree p2 = TYPE_ARG_TYPES (t2);
 397         int len;
 398         tree newargs, n;
 399         int i;
 400
 401         /* Save space: see if the result is identical to one of the args.  */
 402         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 403           return build_type_attribute_variant (t1, attributes);
 404         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 405           return build_type_attribute_variant (t2, attributes);
 406
 407         /* Simple way if one arg fails to specify argument types.  */
 408         if (TYPE_ARG_TYPES (t1) == 0)
 409          {
 410             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 411             t1 = build_type_attribute_variant (t1, attributes);
 412             return qualify_type (t1, t2);
 413          }
 414         if (TYPE_ARG_TYPES (t2) == 0)
 415          {
 416            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 417            t1 = build_type_attribute_variant (t1, attributes);
 418            return qualify_type (t1, t2);
 419          }
 420
 421         /* If both args specify argument types, we must merge the two
 422            lists, argument by argument.  */
 423         /* Tell global_bindings_p to return false so that variable_size
 424            doesn't die on VLAs in parameter types.  */
 425         c_override_global_bindings_to_false = true;
 426
 427         len = list_length (p1);
 428         newargs = 0;
 429
 430         for (i = 0; i < len; i++)
 431           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 432
 433         n = newargs;
 434
 435         for (; p1;
 436              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 437           {
 438             /* A null type means arg type is not specified.
 439                Take whatever the other function type has.  */
 440             if (TREE_VALUE (p1) == 0)
 441               {
 442                 TREE_VALUE (n) = TREE_VALUE (p2);
 443                 goto parm_done;
 444               }
 445             if (TREE_VALUE (p2) == 0)
 446               {
 447                 TREE_VALUE (n) = TREE_VALUE (p1);
 448                 goto parm_done;
 449               }
 450
 451             /* Given  wait (union {union wait *u; int *i} *)
 452                and  wait (union wait *),
 453                prefer  union wait *  as type of parm.  */
 454             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 455                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 456               {
 457                 tree memb;
 458                 tree mv2 = TREE_VALUE (p2);
 459                 if (mv2 && mv2 != error_mark_node
 460                     && TREE_CODE (mv2) != ARRAY_TYPE)
 461                   mv2 = TYPE_MAIN_VARIANT (mv2);
 462                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 463                      memb; memb = TREE_CHAIN (memb))
 464                   {
 465                     tree mv3 = TREE_TYPE (memb);
 466                     if (mv3 && mv3 != error_mark_node
 467                         && TREE_CODE (mv3) != ARRAY_TYPE)
 468                       mv3 = TYPE_MAIN_VARIANT (mv3);
 469                     if (comptypes (mv3, mv2))
 470                       {
 471                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 472                                                          TREE_VALUE (p2));
 473                         pedwarn (OPT_pedantic,
 474                                  "function types not truly compatible in ISO C");
 475                         goto parm_done;
 476                       }
 477                   }
 478               }
 479             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 480                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 481               {
 482                 tree memb;
 483                 tree mv1 = TREE_VALUE (p1);
 484                 if (mv1 && mv1 != error_mark_node
 485                     && TREE_CODE (mv1) != ARRAY_TYPE)
 486                   mv1 = TYPE_MAIN_VARIANT (mv1);
 487                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 488                      memb; memb = TREE_CHAIN (memb))
 489                   {
 490                     tree mv3 = TREE_TYPE (memb);
 491                     if (mv3 && mv3 != error_mark_node
 492                         && TREE_CODE (mv3) != ARRAY_TYPE)
 493                       mv3 = TYPE_MAIN_VARIANT (mv3);
 494                     if (comptypes (mv3, mv1))
 495                       {
 496                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 497                                                          TREE_VALUE (p1));
 498                         pedwarn (OPT_pedantic,
 499                                  "function types not truly compatible in ISO C");
 500                         goto parm_done;
 501                       }
 502                   }
 503               }
 504             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 505           parm_done: ;
 506           }
 507
 508         c_override_global_bindings_to_false = false;
 509         t1 = build_function_type (valtype, newargs);
 510         t1 = qualify_type (t1, t2);
 511         /* ... falls through ...  */
 512       }
 513
 514     default:
 515       return build_type_attribute_variant (t1, attributes);
 516     }
 517
 518 }
 519
 520 /* Return the type of a conditional expression between pointers to
 521    possibly differently qualified versions of compatible types.
 522
 523    We assume that comp_target_types has already been done and returned
 524    nonzero; if that isn't so, this may crash.  */
 525
 526 static tree
 527 common_pointer_type (tree t1, tree t2)
 528 {
 529   tree attributes;
 530   tree pointed_to_1, mv1;
 531   tree pointed_to_2, mv2;
 532   tree target;
 533   unsigned target_quals;
 534
 535   /* Save time if the two types are the same.  */
 536
 537   if (t1 == t2) return t1;
 538
 539   /* If one type is nonsense, use the other.  */
 540   if (t1 == error_mark_node)
 541     return t2;
 542   if (t2 == error_mark_node)
 543     return t1;
 544
 545   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 546               && TREE_CODE (t2) == POINTER_TYPE);
 547
 548   /* Merge the attributes.  */
 549   attributes = targetm.merge_type_attributes (t1, t2);
 550
 551   /* Find the composite type of the target types, and combine the
 552      qualifiers of the two types' targets.  Do not lose qualifiers on
 553      array element types by taking the TYPE_MAIN_VARIANT.  */
 554   mv1 = pointed_to_1 = TREE_TYPE (t1);
 555   mv2 = pointed_to_2 = TREE_TYPE (t2);
 556   if (TREE_CODE (mv1) != ARRAY_TYPE)
 557     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 558   if (TREE_CODE (mv2) != ARRAY_TYPE)
 559     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 560   target = composite_type (mv1, mv2);
 561
 562   /* For function types do not merge const qualifiers, but drop them
 563      if used inconsistently.  The middle-end uses these to mark const
 564      and noreturn functions.  */
 565   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 566     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 567   else
 568     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 569   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 570   return build_type_attribute_variant (t1, attributes);
 571 }
 572
 573 /* Return the common type for two arithmetic types under the usual
 574    arithmetic conversions.  The default conversions have already been
 575    applied, and enumerated types converted to their compatible integer
 576    types.  The resulting type is unqualified and has no attributes.
 577
 578    This is the type for the result of most arithmetic operations
 579    if the operands have the given two types.  */
 580
 581 static tree
 582 c_common_type (tree t1, tree t2)
 583 {
 584   enum tree_code code1;
 585   enum tree_code code2;
 586
 587   /* If one type is nonsense, use the other.  */
 588   if (t1 == error_mark_node)
 589     return t2;
 590   if (t2 == error_mark_node)
 591     return t1;
 592
 593   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 594     t1 = TYPE_MAIN_VARIANT (t1);
 595
 596   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 597     t2 = TYPE_MAIN_VARIANT (t2);
 598
 599   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 600     t1 = build_type_attribute_variant (t1, NULL_TREE);
 601
 602   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 603     t2 = build_type_attribute_variant (t2, NULL_TREE);
 604
 605   /* Save time if the two types are the same.  */
 606
 607   if (t1 == t2) return t1;
 608
 609   code1 = TREE_CODE (t1);
 610   code2 = TREE_CODE (t2);
 611
 612   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 613               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 614               || code1 == INTEGER_TYPE);
 615   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 616               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 617               || code2 == INTEGER_TYPE);
 618
 619   /* When one operand is a decimal float type, the other operand cannot be
 620      a generic float type or a complex type.  We also disallow vector types
 621      here.  */
 622   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 623       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 624     {
 625       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 626         {
 627           error ("can%'t mix operands of decimal float and vector types");
 628           return error_mark_node;
 629         }
 630       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 631         {
 632           error ("can%'t mix operands of decimal float and complex types");
 633           return error_mark_node;
 634         }
 635       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 636         {
 637           error ("can%'t mix operands of decimal float and other float types");
 638           return error_mark_node;
 639         }
 640     }
 641
 642   /* If one type is a vector type, return that type.  (How the usual
 643      arithmetic conversions apply to the vector types extension is not
 644      precisely specified.)  */
 645   if (code1 == VECTOR_TYPE)
 646     return t1;
 647
 648   if (code2 == VECTOR_TYPE)
 649     return t2;
 650
 651   /* If one type is complex, form the common type of the non-complex
 652      components, then make that complex.  Use T1 or T2 if it is the
 653      required type.  */
 654   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 655     {
 656       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 657       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 658       tree subtype = c_common_type (subtype1, subtype2);
 659
 660       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 661         return t1;
 662       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 663         return t2;
 664       else
 665         return build_complex_type (subtype);
 666     }
 667
 668   /* If only one is real, use it as the result.  */
 669
 670   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 671     return t1;
 672
 673   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 674     return t2;
 675
 676   /* If both are real and either are decimal floating point types, use
 677      the decimal floating point type with the greater precision. */
 678
 679   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 680     {
 681       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 682           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 683         return dfloat128_type_node;
 684       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 685                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 686         return dfloat64_type_node;
 687       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 688                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 689         return dfloat32_type_node;
 690     }
 691
 692   /* Deal with fixed-point types.  */
 693   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 694     {
 695       unsigned int unsignedp = 0, satp = 0;
 696       enum machine_mode m1, m2;
 697       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 698
 699       m1 = TYPE_MODE (t1);
 700       m2 = TYPE_MODE (t2);
 701
 702       /* If one input type is saturating, the result type is saturating.  */
 703       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 704         satp = 1;
 705
 706       /* If both fixed-point types are unsigned, the result type is unsigned.
 707          When mixing fixed-point and integer types, follow the sign of the
 708          fixed-point type.
 709          Otherwise, the result type is signed.  */
 710       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 711            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 712           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 713               && TYPE_UNSIGNED (t1))
 714           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 715               && TYPE_UNSIGNED (t2)))
 716         unsignedp = 1;
 717
 718       /* The result type is signed.  */
 719       if (unsignedp == 0)
 720         {
 721           /* If the input type is unsigned, we need to convert to the
 722              signed type.  */
 723           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 724             {
 725               enum mode_class mclass = (enum mode_class) 0;
 726               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 727                 mclass = MODE_FRACT;
 728               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 729                 mclass = MODE_ACCUM;
 730               else
 731                 gcc_unreachable ();
 732               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 733             }
 734           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 735             {
 736               enum mode_class mclass = (enum mode_class) 0;
 737               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 738                 mclass = MODE_FRACT;
 739               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 740                 mclass = MODE_ACCUM;
 741               else
 742                 gcc_unreachable ();
 743               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 744             }
 745         }
 746
 747       if (code1 == FIXED_POINT_TYPE)
 748         {
 749           fbit1 = GET_MODE_FBIT (m1);
 750           ibit1 = GET_MODE_IBIT (m1);
 751         }
 752       else
 753         {
 754           fbit1 = 0;
 755           /* Signed integers need to subtract one sign bit.  */
 756           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 757         }
 758
 759       if (code2 == FIXED_POINT_TYPE)
 760         {
 761           fbit2 = GET_MODE_FBIT (m2);
 762           ibit2 = GET_MODE_IBIT (m2);
 763         }
 764       else
 765         {
 766           fbit2 = 0;
 767           /* Signed integers need to subtract one sign bit.  */
 768           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 769         }
 770
 771       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 772       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 773       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 774                                                  satp);
 775     }
 776
 777   /* Both real or both integers; use the one with greater precision.  */
 778
 779   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 780     return t1;
 781   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 782     return t2;
 783
 784   /* Same precision.  Prefer long longs to longs to ints when the
 785      same precision, following the C99 rules on integer type rank
 786      (which are equivalent to the C90 rules for C90 types).  */
 787
 788   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 789       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 790     return long_long_unsigned_type_node;
 791
 792   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 793       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 794     {
 795       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 796         return long_long_unsigned_type_node;
 797       else
 798         return long_long_integer_type_node;
 799     }
 800
 801   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 802       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 803     return long_unsigned_type_node;
 804
 805   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 806       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 807     {
 808       /* But preserve unsignedness from the other type,
 809          since long cannot hold all the values of an unsigned int.  */
 810       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 811         return long_unsigned_type_node;
 812       else
 813         return long_integer_type_node;
 814     }
 815
 816   /* Likewise, prefer long double to double even if same size.  */
 817   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 818       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 819     return long_double_type_node;
 820
 821   /* Otherwise prefer the unsigned one.  */
 822
 823   if (TYPE_UNSIGNED (t1))
 824     return t1;
 825   else
 826     return t2;
 827 }
 828 \f
 829 /* Wrapper around c_common_type that is used by c-common.c and other
 830    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 831    are allowed here and are converted to their compatible integer types.
 832    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 833    preferably a non-Boolean type as the common type.  */
 834 tree
 835 common_type (tree t1, tree t2)
 836 {
 837   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 838     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 839   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 840     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 841
 842   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 843   if (TREE_CODE (t1) == BOOLEAN_TYPE
 844       && TREE_CODE (t2) == BOOLEAN_TYPE)
 845     return boolean_type_node;
 846
 847   /* If either type is BOOLEAN_TYPE, then return the other.  */
 848   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 849     return t2;
 850   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 851     return t1;
 852
 853   return c_common_type (t1, t2);
 854 }
 855
 856 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 857    or various other operations.  Return 2 if they are compatible
 858    but a warning may be needed if you use them together.  */
 859
 860 int
 861 comptypes (tree type1, tree type2)
 862 {
 863   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 864   int val;
 865
 866   val = comptypes_internal (type1, type2);
 867   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 868
 869   return val;
 870 }
 871 \f
 872 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 873    or various other operations.  Return 2 if they are compatible
 874    but a warning may be needed if you use them together.  This
 875    differs from comptypes, in that we don't free the seen types.  */
 876
 877 static int
 878 comptypes_internal (const_tree type1, const_tree type2)
 879 {
 880   const_tree t1 = type1;
 881   const_tree t2 = type2;
 882   int attrval, val;
 883
 884   /* Suppress errors caused by previously reported errors.  */
 885
 886   if (t1 == t2 || !t1 || !t2
 887       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 888     return 1;
 889
 890   /* If either type is the internal version of sizetype, return the
 891      language version.  */
 892   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 893       && TYPE_ORIG_SIZE_TYPE (t1))
 894     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 895
 896   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 897       && TYPE_ORIG_SIZE_TYPE (t2))
 898     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 899
 900
 901   /* Enumerated types are compatible with integer types, but this is
 902      not transitive: two enumerated types in the same translation unit
 903      are compatible with each other only if they are the same type.  */
 904
 905   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 906     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 907   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 908     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 909
 910   if (t1 == t2)
 911     return 1;
 912
 913   /* Different classes of types can't be compatible.  */
 914
 915   if (TREE_CODE (t1) != TREE_CODE (t2))
 916     return 0;
 917
 918   /* Qualifiers must match. C99 6.7.3p9 */
 919
 920   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 921     return 0;
 922
 923   /* Allow for two different type nodes which have essentially the same
 924      definition.  Note that we already checked for equality of the type
 925      qualifiers (just above).  */
 926
 927   if (TREE_CODE (t1) != ARRAY_TYPE
 928       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 929     return 1;
 930
 931   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 932   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 933      return 0;
 934
 935   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 936   val = 0;
 937
 938   switch (TREE_CODE (t1))
 939     {
 940     case POINTER_TYPE:
 941       /* Do not remove mode or aliasing information.  */
 942       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 943           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 944         break;
 945       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 946              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 947       break;
 948
 949     case FUNCTION_TYPE:
 950       val = function_types_compatible_p (t1, t2);
 951       break;
 952
 953     case ARRAY_TYPE:
 954       {
 955         tree d1 = TYPE_DOMAIN (t1);
 956         tree d2 = TYPE_DOMAIN (t2);
 957         bool d1_variable, d2_variable;
 958         bool d1_zero, d2_zero;
 959         val = 1;
 960
 961         /* Target types must match incl. qualifiers.  */
 962         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 963             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 964           return 0;
 965
 966         /* Sizes must match unless one is missing or variable.  */
 967         if (d1 == 0 || d2 == 0 || d1 == d2)
 968           break;
 969
 970         d1_zero = !TYPE_MAX_VALUE (d1);
 971         d2_zero = !TYPE_MAX_VALUE (d2);
 972
 973         d1_variable = (!d1_zero
 974                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 975                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 976         d2_variable = (!d2_zero
 977                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 978                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 979         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 980         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 981
 982         if (d1_variable || d2_variable)
 983           break;
 984         if (d1_zero && d2_zero)
 985           break;
 986         if (d1_zero || d2_zero
 987             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 988             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 989           val = 0;
 990
 991         break;
 992       }
 993
 994     case ENUMERAL_TYPE:
 995     case RECORD_TYPE:
 996     case UNION_TYPE:
 997       if (val != 1 && !same_translation_unit_p (t1, t2))
 998         {
 999           tree a1 = TYPE_ATTRIBUTES (t1);
1000           tree a2 = TYPE_ATTRIBUTES (t2);
1001
1002           if (! attribute_list_contained (a1, a2)
1003               && ! attribute_list_contained (a2, a1))
1004             break;
1005
1006           if (attrval != 2)
1007             return tagged_types_tu_compatible_p (t1, t2);
1008           val = tagged_types_tu_compatible_p (t1, t2);
1009         }
1010       break;
1011
1012     case VECTOR_TYPE:
1013       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1014             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1015       break;
1016
1017     default:
1018       break;
1019     }
1020   return attrval == 2 && val == 1 ? 2 : val;
1021 }
1022
1023 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1024    ignoring their qualifiers.  */
1025
1026 static int
1027 comp_target_types (tree ttl, tree ttr)
1028 {
1029   int val;
1030   tree mvl, mvr;
1031
1032   /* Do not lose qualifiers on element types of array types that are
1033      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1034   mvl = TREE_TYPE (ttl);
1035   mvr = TREE_TYPE (ttr);
1036   if (TREE_CODE (mvl) != ARRAY_TYPE)
1037     mvl = TYPE_MAIN_VARIANT (mvl);
1038   if (TREE_CODE (mvr) != ARRAY_TYPE)
1039     mvr = TYPE_MAIN_VARIANT (mvr);
1040   val = comptypes (mvl, mvr);
1041
1042   if (val == 2)
1043     pedwarn (OPT_pedantic, "types are not quite compatible");
1044   return val;
1045 }
1046 \f
1047 /* Subroutines of `comptypes'.  */
1048
1049 /* Determine whether two trees derive from the same translation unit.
1050    If the CONTEXT chain ends in a null, that tree's context is still
1051    being parsed, so if two trees have context chains ending in null,
1052    they're in the same translation unit.  */
1053 int
1054 same_translation_unit_p (const_tree t1, const_tree t2)
1055 {
1056   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1057     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1058       {
1059       case tcc_declaration:
1060         t1 = DECL_CONTEXT (t1); break;
1061       case tcc_type:
1062         t1 = TYPE_CONTEXT (t1); break;
1063       case tcc_exceptional:
1064         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1065       default: gcc_unreachable ();
1066       }
1067
1068   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1069     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1070       {
1071       case tcc_declaration:
1072         t2 = DECL_CONTEXT (t2); break;
1073       case tcc_type:
1074         t2 = TYPE_CONTEXT (t2); break;
1075       case tcc_exceptional:
1076         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1077       default: gcc_unreachable ();
1078       }
1079
1080   return t1 == t2;
1081 }
1082
1083 /* Allocate the seen two types, assuming that they are compatible. */
1084
1085 static struct tagged_tu_seen_cache *
1086 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1087 {
1088   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1089   tu->next = tagged_tu_seen_base;
1090   tu->t1 = t1;
1091   tu->t2 = t2;
1092
1093   tagged_tu_seen_base = tu;
1094
1095   /* The C standard says that two structures in different translation
1096      units are compatible with each other only if the types of their
1097      fields are compatible (among other things).  We assume that they
1098      are compatible until proven otherwise when building the cache.
1099      An example where this can occur is:
1100      struct a
1101      {
1102        struct a *next;
1103      };
1104      If we are comparing this against a similar struct in another TU,
1105      and did not assume they were compatible, we end up with an infinite
1106      loop.  */
1107   tu->val = 1;
1108   return tu;
1109 }
1110
1111 /* Free the seen types until we get to TU_TIL. */
1112
1113 static void
1114 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1115 {
1116   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1117   while (tu != tu_til)
1118     {
1119       const struct tagged_tu_seen_cache *const tu1
1120         = (const struct tagged_tu_seen_cache *) tu;
1121       tu = tu1->next;
1122       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1123     }
1124   tagged_tu_seen_base = tu_til;
1125 }
1126
1127 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1128    compatible.  If the two types are not the same (which has been
1129    checked earlier), this can only happen when multiple translation
1130    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1131    rules.  */
1132
1133 static int
1134 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1135 {
1136   tree s1, s2;
1137   bool needs_warning = false;
1138
1139   /* We have to verify that the tags of the types are the same.  This
1140      is harder than it looks because this may be a typedef, so we have
1141      to go look at the original type.  It may even be a typedef of a
1142      typedef...
1143      In the case of compiler-created builtin structs the TYPE_DECL
1144      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1145   while (TYPE_NAME (t1)
1146          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1147          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1148     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1149
1150   while (TYPE_NAME (t2)
1151          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1152          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1153     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1154
1155   /* C90 didn't have the requirement that the two tags be the same.  */
1156   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1157     return 0;
1158
1159   /* C90 didn't say what happened if one or both of the types were
1160      incomplete; we choose to follow C99 rules here, which is that they
1161      are compatible.  */
1162   if (TYPE_SIZE (t1) == NULL
1163       || TYPE_SIZE (t2) == NULL)
1164     return 1;
1165
1166   {
1167     const struct tagged_tu_seen_cache * tts_i;
1168     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1169       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1170         return tts_i->val;
1171   }
1172
1173   switch (TREE_CODE (t1))
1174     {
1175     case ENUMERAL_TYPE:
1176       {
1177         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1178         /* Speed up the case where the type values are in the same order.  */
1179         tree tv1 = TYPE_VALUES (t1);
1180         tree tv2 = TYPE_VALUES (t2);
1181
1182         if (tv1 == tv2)
1183           {
1184             return 1;
1185           }
1186
1187         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1188           {
1189             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1190               break;
1191             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1192               {
1193                 tu->val = 0;
1194                 return 0;
1195               }
1196           }
1197
1198         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1199           {
1200             return 1;
1201           }
1202         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1203           {
1204             tu->val = 0;
1205             return 0;
1206           }
1207
1208         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1209           {
1210             tu->val = 0;
1211             return 0;
1212           }
1213
1214         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1215           {
1216             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1217             if (s2 == NULL
1218                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1219               {
1220                 tu->val = 0;
1221                 return 0;
1222               }
1223           }
1224         return 1;
1225       }
1226
1227     case UNION_TYPE:
1228       {
1229         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1230         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1231           {
1232             tu->val = 0;
1233             return 0;
1234           }
1235
1236         /*  Speed up the common case where the fields are in the same order. */
1237         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1238              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1239           {
1240             int result;
1241
1242             if (DECL_NAME (s1) != DECL_NAME (s2))
1243               break;
1244             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1245
1246             if (result != 1 && !DECL_NAME (s1))
1247               break;
1248             if (result == 0)
1249               {
1250                 tu->val = 0;
1251                 return 0;
1252               }
1253             if (result == 2)
1254               needs_warning = true;
1255
1256             if (TREE_CODE (s1) == FIELD_DECL
1257                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1258                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1259               {
1260                 tu->val = 0;
1261                 return 0;
1262               }
1263           }
1264         if (!s1 && !s2)
1265           {
1266             tu->val = needs_warning ? 2 : 1;
1267             return tu->val;
1268           }
1269
1270         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1271           {
1272             bool ok = false;
1273
1274             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1275               if (DECL_NAME (s1) == DECL_NAME (s2))
1276                 {
1277                   int result;
1278
1279                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1280
1281                   if (result != 1 && !DECL_NAME (s1))
1282                     continue;
1283                   if (result == 0)
1284                     {
1285                       tu->val = 0;
1286                       return 0;
1287                     }
1288                   if (result == 2)
1289                     needs_warning = true;
1290
1291                   if (TREE_CODE (s1) == FIELD_DECL
1292                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1293                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1294                     break;
1295
1296                   ok = true;
1297                   break;
1298                 }
1299             if (!ok)
1300               {
1301                 tu->val = 0;
1302                 return 0;
1303               }
1304           }
1305         tu->val = needs_warning ? 2 : 10;
1306         return tu->val;
1307       }
1308
1309     case RECORD_TYPE:
1310       {
1311         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1312
1313         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1314              s1 && s2;
1315              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1316           {
1317             int result;
1318             if (TREE_CODE (s1) != TREE_CODE (s2)
1319                 || DECL_NAME (s1) != DECL_NAME (s2))
1320               break;
1321             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1322             if (result == 0)
1323               break;
1324             if (result == 2)
1325               needs_warning = true;
1326
1327             if (TREE_CODE (s1) == FIELD_DECL
1328                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1329                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1330               break;
1331           }
1332         if (s1 && s2)
1333           tu->val = 0;
1334         else
1335           tu->val = needs_warning ? 2 : 1;
1336         return tu->val;
1337       }
1338
1339     default:
1340       gcc_unreachable ();
1341     }
1342 }
1343
1344 /* Return 1 if two function types F1 and F2 are compatible.
1345    If either type specifies no argument types,
1346    the other must specify a fixed number of self-promoting arg types.
1347    Otherwise, if one type specifies only the number of arguments,
1348    the other must specify that number of self-promoting arg types.
1349    Otherwise, the argument types must match.  */
1350
1351 static int
1352 function_types_compatible_p (const_tree f1, const_tree f2)
1353 {
1354   tree args1, args2;
1355   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1356   int val = 1;
1357   int val1;
1358   tree ret1, ret2;
1359
1360   ret1 = TREE_TYPE (f1);
1361   ret2 = TREE_TYPE (f2);
1362
1363   /* 'volatile' qualifiers on a function's return type used to mean
1364      the function is noreturn.  */
1365   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1366     pedwarn (0, "function return types not compatible due to %<volatile%>");
1367   if (TYPE_VOLATILE (ret1))
1368     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1369                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1370   if (TYPE_VOLATILE (ret2))
1371     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1372                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1373   val = comptypes_internal (ret1, ret2);
1374   if (val == 0)
1375     return 0;
1376
1377   args1 = TYPE_ARG_TYPES (f1);
1378   args2 = TYPE_ARG_TYPES (f2);
1379
1380   /* An unspecified parmlist matches any specified parmlist
1381      whose argument types don't need default promotions.  */
1382
1383   if (args1 == 0)
1384     {
1385       if (!self_promoting_args_p (args2))
1386         return 0;
1387       /* If one of these types comes from a non-prototype fn definition,
1388          compare that with the other type's arglist.
1389          If they don't match, ask for a warning (but no error).  */
1390       if (TYPE_ACTUAL_ARG_TYPES (f1)
1391           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1392         val = 2;
1393       return val;
1394     }
1395   if (args2 == 0)
1396     {
1397       if (!self_promoting_args_p (args1))
1398         return 0;
1399       if (TYPE_ACTUAL_ARG_TYPES (f2)
1400           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1401         val = 2;
1402       return val;
1403     }
1404
1405   /* Both types have argument lists: compare them and propagate results.  */
1406   val1 = type_lists_compatible_p (args1, args2);
1407   return val1 != 1 ? val1 : val;
1408 }
1409
1410 /* Check two lists of types for compatibility,
1411    returning 0 for incompatible, 1 for compatible,
1412    or 2 for compatible with warning.  */
1413
1414 static int
1415 type_lists_compatible_p (const_tree args1, const_tree args2)
1416 {
1417   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1418   int val = 1;
1419   int newval = 0;
1420
1421   while (1)
1422     {
1423       tree a1, mv1, a2, mv2;
1424       if (args1 == 0 && args2 == 0)
1425         return val;
1426       /* If one list is shorter than the other,
1427          they fail to match.  */
1428       if (args1 == 0 || args2 == 0)
1429         return 0;
1430       mv1 = a1 = TREE_VALUE (args1);
1431       mv2 = a2 = TREE_VALUE (args2);
1432       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1433         mv1 = TYPE_MAIN_VARIANT (mv1);
1434       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1435         mv2 = TYPE_MAIN_VARIANT (mv2);
1436       /* A null pointer instead of a type
1437          means there is supposed to be an argument
1438          but nothing is specified about what type it has.
1439          So match anything that self-promotes.  */
1440       if (a1 == 0)
1441         {
1442           if (c_type_promotes_to (a2) != a2)
1443             return 0;
1444         }
1445       else if (a2 == 0)
1446         {
1447           if (c_type_promotes_to (a1) != a1)
1448             return 0;
1449         }
1450       /* If one of the lists has an error marker, ignore this arg.  */
1451       else if (TREE_CODE (a1) == ERROR_MARK
1452                || TREE_CODE (a2) == ERROR_MARK)
1453         ;
1454       else if (!(newval = comptypes_internal (mv1, mv2)))
1455         {
1456           /* Allow  wait (union {union wait *u; int *i} *)
1457              and  wait (union wait *)  to be compatible.  */
1458           if (TREE_CODE (a1) == UNION_TYPE
1459               && (TYPE_NAME (a1) == 0
1460                   || TYPE_TRANSPARENT_UNION (a1))
1461               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1462               && tree_int_cst_equal (TYPE_SIZE (a1),
1463                                      TYPE_SIZE (a2)))
1464             {
1465               tree memb;
1466               for (memb = TYPE_FIELDS (a1);
1467                    memb; memb = TREE_CHAIN (memb))
1468                 {
1469                   tree mv3 = TREE_TYPE (memb);
1470                   if (mv3 && mv3 != error_mark_node
1471                       && TREE_CODE (mv3) != ARRAY_TYPE)
1472                     mv3 = TYPE_MAIN_VARIANT (mv3);
1473                   if (comptypes_internal (mv3, mv2))
1474                     break;
1475                 }
1476               if (memb == 0)
1477                 return 0;
1478             }
1479           else if (TREE_CODE (a2) == UNION_TYPE
1480                    && (TYPE_NAME (a2) == 0
1481                        || TYPE_TRANSPARENT_UNION (a2))
1482                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1483                    && tree_int_cst_equal (TYPE_SIZE (a2),
1484                                           TYPE_SIZE (a1)))
1485             {
1486               tree memb;
1487               for (memb = TYPE_FIELDS (a2);
1488                    memb; memb = TREE_CHAIN (memb))
1489                 {
1490                   tree mv3 = TREE_TYPE (memb);
1491                   if (mv3 && mv3 != error_mark_node
1492                       && TREE_CODE (mv3) != ARRAY_TYPE)
1493                     mv3 = TYPE_MAIN_VARIANT (mv3);
1494                   if (comptypes_internal (mv3, mv1))
1495                     break;
1496                 }
1497               if (memb == 0)
1498                 return 0;
1499             }
1500           else
1501             return 0;
1502         }
1503
1504       /* comptypes said ok, but record if it said to warn.  */
1505       if (newval > val)
1506         val = newval;
1507
1508       args1 = TREE_CHAIN (args1);
1509       args2 = TREE_CHAIN (args2);
1510     }
1511 }
1512 \f
1513 /* Compute the size to increment a pointer by.  */
1514
1515 static tree
1516 c_size_in_bytes (const_tree type)
1517 {
1518   enum tree_code code = TREE_CODE (type);
1519
1520   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1521     return size_one_node;
1522
1523   if (!COMPLETE_OR_VOID_TYPE_P (type))
1524     {
1525       error ("arithmetic on pointer to an incomplete type");
1526       return size_one_node;
1527     }
1528
1529   /* Convert in case a char is more than one unit.  */
1530   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1531                      size_int (TYPE_PRECISION (char_type_node)
1532                                / BITS_PER_UNIT));
1533 }
1534 \f
1535 /* Return either DECL or its known constant value (if it has one).  */
1536
1537 tree
1538 decl_constant_value (tree decl)
1539 {
1540   if (/* Don't change a variable array bound or initial value to a constant
1541          in a place where a variable is invalid.  Note that DECL_INITIAL
1542          isn't valid for a PARM_DECL.  */
1543       current_function_decl != 0
1544       && TREE_CODE (decl) != PARM_DECL
1545       && !TREE_THIS_VOLATILE (decl)
1546       && TREE_READONLY (decl)
1547       && DECL_INITIAL (decl) != 0
1548       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1549       /* This is invalid if initial value is not constant.
1550          If it has either a function call, a memory reference,
1551          or a variable, then re-evaluating it could give different results.  */
1552       && TREE_CONSTANT (DECL_INITIAL (decl))
1553       /* Check for cases where this is sub-optimal, even though valid.  */
1554       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1555     return DECL_INITIAL (decl);
1556   return decl;
1557 }
1558
1559 /* Return either DECL or its known constant value (if it has one), but
1560    return DECL if pedantic or DECL has mode BLKmode.  This is for
1561    bug-compatibility with the old behavior of decl_constant_value
1562    (before GCC 3.0); every use of this function is a bug and it should
1563    be removed before GCC 3.1.  It is not appropriate to use pedantic
1564    in a way that affects optimization, and BLKmode is probably not the
1565    right test for avoiding misoptimizations either.  */
1566
1567 static tree
1568 decl_constant_value_for_broken_optimization (tree decl)
1569 {
1570   tree ret;
1571
1572   if (pedantic || DECL_MODE (decl) == BLKmode)
1573     return decl;
1574
1575   ret = decl_constant_value (decl);
1576   /* Avoid unwanted tree sharing between the initializer and current
1577      function's body where the tree can be modified e.g. by the
1578      gimplifier.  */
1579   if (ret != decl && TREE_STATIC (decl))
1580     ret = unshare_expr (ret);
1581   return ret;
1582 }
1583
1584 /* Convert the array expression EXP to a pointer.  */
1585 static tree
1586 array_to_pointer_conversion (tree exp)
1587 {
1588   tree orig_exp = exp;
1589   tree type = TREE_TYPE (exp);
1590   tree adr;
1591   tree restype = TREE_TYPE (type);
1592   tree ptrtype;
1593
1594   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1595
1596   STRIP_TYPE_NOPS (exp);
1597
1598   if (TREE_NO_WARNING (orig_exp))
1599     TREE_NO_WARNING (exp) = 1;
1600
1601   ptrtype = build_pointer_type (restype);
1602
1603   if (TREE_CODE (exp) == INDIRECT_REF)
1604     return convert (ptrtype, TREE_OPERAND (exp, 0));
1605
1606   if (TREE_CODE (exp) == VAR_DECL)
1607     {
1608       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1609          ADDR_EXPR because it's the best way of representing what
1610          happens in C when we take the address of an array and place
1611          it in a pointer to the element type.  */
1612       adr = build1 (ADDR_EXPR, ptrtype, exp);
1613       if (!c_mark_addressable (exp))
1614         return error_mark_node;
1615       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1616       return adr;
1617     }
1618
1619   /* This way is better for a COMPONENT_REF since it can
1620      simplify the offset for a component.  */
1621   adr = build_unary_op (ADDR_EXPR, exp, 1);
1622   return convert (ptrtype, adr);
1623 }
1624
1625 /* Convert the function expression EXP to a pointer.  */
1626 static tree
1627 function_to_pointer_conversion (tree exp)
1628 {
1629   tree orig_exp = exp;
1630
1631   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1632
1633   STRIP_TYPE_NOPS (exp);
1634
1635   if (TREE_NO_WARNING (orig_exp))
1636     TREE_NO_WARNING (exp) = 1;
1637
1638   return build_unary_op (ADDR_EXPR, exp, 0);
1639 }
1640
1641 /* Perform the default conversion of arrays and functions to pointers.
1642    Return the result of converting EXP.  For any other expression, just
1643    return EXP after removing NOPs.  */
1644
1645 struct c_expr
1646 default_function_array_conversion (struct c_expr exp)
1647 {
1648   tree orig_exp = exp.value;
1649   tree type = TREE_TYPE (exp.value);
1650   enum tree_code code = TREE_CODE (type);
1651
1652   switch (code)
1653     {
1654     case ARRAY_TYPE:
1655       {
1656         bool not_lvalue = false;
1657         bool lvalue_array_p;
1658
1659         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1660                 || CONVERT_EXPR_P (exp.value))
1661                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1662           {
1663             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1664               not_lvalue = true;
1665             exp.value = TREE_OPERAND (exp.value, 0);
1666           }
1667
1668         if (TREE_NO_WARNING (orig_exp))
1669           TREE_NO_WARNING (exp.value) = 1;
1670
1671         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1672         if (!flag_isoc99 && !lvalue_array_p)
1673           {
1674             /* Before C99, non-lvalue arrays do not decay to pointers.
1675                Normally, using such an array would be invalid; but it can
1676                be used correctly inside sizeof or as a statement expression.
1677                Thus, do not give an error here; an error will result later.  */
1678             return exp;
1679           }
1680
1681         exp.value = array_to_pointer_conversion (exp.value);
1682       }
1683       break;
1684     case FUNCTION_TYPE:
1685       exp.value = function_to_pointer_conversion (exp.value);
1686       break;
1687     default:
1688       STRIP_TYPE_NOPS (exp.value);
1689       if (TREE_NO_WARNING (orig_exp))
1690         TREE_NO_WARNING (exp.value) = 1;
1691       break;
1692     }
1693
1694   return exp;
1695 }
1696
1697
1698 /* EXP is an expression of integer type.  Apply the integer promotions
1699    to it and return the promoted value.  */
1700
1701 tree
1702 perform_integral_promotions (tree exp)
1703 {
1704   tree type = TREE_TYPE (exp);
1705   enum tree_code code = TREE_CODE (type);
1706
1707   gcc_assert (INTEGRAL_TYPE_P (type));
1708
1709   /* Normally convert enums to int,
1710      but convert wide enums to something wider.  */
1711   if (code == ENUMERAL_TYPE)
1712     {
1713       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1714                                           TYPE_PRECISION (integer_type_node)),
1715                                      ((TYPE_PRECISION (type)
1716                                        >= TYPE_PRECISION (integer_type_node))
1717                                       && TYPE_UNSIGNED (type)));
1718
1719       return convert (type, exp);
1720     }
1721
1722   /* ??? This should no longer be needed now bit-fields have their
1723      proper types.  */
1724   if (TREE_CODE (exp) == COMPONENT_REF
1725       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1726       /* If it's thinner than an int, promote it like a
1727          c_promoting_integer_type_p, otherwise leave it alone.  */
1728       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1729                                TYPE_PRECISION (integer_type_node)))
1730     return convert (integer_type_node, exp);
1731
1732   if (c_promoting_integer_type_p (type))
1733     {
1734       /* Preserve unsignedness if not really getting any wider.  */
1735       if (TYPE_UNSIGNED (type)
1736           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1737         return convert (unsigned_type_node, exp);
1738
1739       return convert (integer_type_node, exp);
1740     }
1741
1742   return exp;
1743 }
1744
1745
1746 /* Perform default promotions for C data used in expressions.
1747    Enumeral types or short or char are converted to int.
1748    In addition, manifest constants symbols are replaced by their values.  */
1749
1750 tree
1751 default_conversion (tree exp)
1752 {
1753   tree orig_exp;
1754   tree type = TREE_TYPE (exp);
1755   enum tree_code code = TREE_CODE (type);
1756
1757   /* Functions and arrays have been converted during parsing.  */
1758   gcc_assert (code != FUNCTION_TYPE);
1759   if (code == ARRAY_TYPE)
1760     return exp;
1761
1762   /* Constants can be used directly unless they're not loadable.  */
1763   if (TREE_CODE (exp) == CONST_DECL)
1764     exp = DECL_INITIAL (exp);
1765
1766   /* Replace a nonvolatile const static variable with its value unless
1767      it is an array, in which case we must be sure that taking the
1768      address of the array produces consistent results.  */
1769   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1770     {
1771       exp = decl_constant_value_for_broken_optimization (exp);
1772       type = TREE_TYPE (exp);
1773     }
1774
1775   /* Strip no-op conversions.  */
1776   orig_exp = exp;
1777   STRIP_TYPE_NOPS (exp);
1778
1779   if (TREE_NO_WARNING (orig_exp))
1780     TREE_NO_WARNING (exp) = 1;
1781
1782   if (code == VOID_TYPE)
1783     {
1784       error ("void value not ignored as it ought to be");
1785       return error_mark_node;
1786     }
1787
1788   exp = require_complete_type (exp);
1789   if (exp == error_mark_node)
1790     return error_mark_node;
1791
1792   if (INTEGRAL_TYPE_P (type))
1793     return perform_integral_promotions (exp);
1794
1795   return exp;
1796 }
1797 \f
1798 /* Look up COMPONENT in a structure or union DECL.
1799
1800    If the component name is not found, returns NULL_TREE.  Otherwise,
1801    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1802    stepping down the chain to the component, which is in the last
1803    TREE_VALUE of the list.  Normally the list is of length one, but if
1804    the component is embedded within (nested) anonymous structures or
1805    unions, the list steps down the chain to the component.  */
1806
1807 static tree
1808 lookup_field (tree decl, tree component)
1809 {
1810   tree type = TREE_TYPE (decl);
1811   tree field;
1812
1813   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1814      to the field elements.  Use a binary search on this array to quickly
1815      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1816      will always be set for structures which have many elements.  */
1817
1818   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1819     {
1820       int bot, top, half;
1821       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1822
1823       field = TYPE_FIELDS (type);
1824       bot = 0;
1825       top = TYPE_LANG_SPECIFIC (type)->s->len;
1826       while (top - bot > 1)
1827         {
1828           half = (top - bot + 1) >> 1;
1829           field = field_array[bot+half];
1830
1831           if (DECL_NAME (field) == NULL_TREE)
1832             {
1833               /* Step through all anon unions in linear fashion.  */
1834               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1835                 {
1836                   field = field_array[bot++];
1837                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1838                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1839                     {
1840                       tree anon = lookup_field (field, component);
1841
1842                       if (anon)
1843                         return tree_cons (NULL_TREE, field, anon);
1844                     }
1845                 }
1846
1847               /* Entire record is only anon unions.  */
1848               if (bot > top)
1849                 return NULL_TREE;
1850
1851               /* Restart the binary search, with new lower bound.  */
1852               continue;
1853             }
1854
1855           if (DECL_NAME (field) == component)
1856             break;
1857           if (DECL_NAME (field) < component)
1858             bot += half;
1859           else
1860             top = bot + half;
1861         }
1862
1863       if (DECL_NAME (field_array[bot]) == component)
1864         field = field_array[bot];
1865       else if (DECL_NAME (field) != component)
1866         return NULL_TREE;
1867     }
1868   else
1869     {
1870       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1871         {
1872           if (DECL_NAME (field) == NULL_TREE
1873               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1874                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1875             {
1876               tree anon = lookup_field (field, component);
1877
1878               if (anon)
1879                 return tree_cons (NULL_TREE, field, anon);
1880             }
1881
1882           if (DECL_NAME (field) == component)
1883             break;
1884         }
1885
1886       if (field == NULL_TREE)
1887         return NULL_TREE;
1888     }
1889
1890   return tree_cons (NULL_TREE, field, NULL_TREE);
1891 }
1892
1893 /* Make an expression to refer to the COMPONENT field of
1894    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1895
1896 tree
1897 build_component_ref (tree datum, tree component)
1898 {
1899   tree type = TREE_TYPE (datum);
1900   enum tree_code code = TREE_CODE (type);
1901   tree field = NULL;
1902   tree ref;
1903
1904   if (!objc_is_public (datum, component))
1905     return error_mark_node;
1906
1907   /* See if there is a field or component with name COMPONENT.  */
1908
1909   if (code == RECORD_TYPE || code == UNION_TYPE)
1910     {
1911       if (!COMPLETE_TYPE_P (type))
1912         {
1913           c_incomplete_type_error (NULL_TREE, type);
1914           return error_mark_node;
1915         }
1916
1917       field = lookup_field (datum, component);
1918
1919       if (!field)
1920         {
1921           error ("%qT has no member named %qE", type, component);
1922           return error_mark_node;
1923         }
1924
1925       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1926          This might be better solved in future the way the C++ front
1927          end does it - by giving the anonymous entities each a
1928          separate name and type, and then have build_component_ref
1929          recursively call itself.  We can't do that here.  */
1930       do
1931         {
1932           tree subdatum = TREE_VALUE (field);
1933           int quals;
1934           tree subtype;
1935
1936           if (TREE_TYPE (subdatum) == error_mark_node)
1937             return error_mark_node;
1938
1939           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1940           quals |= TYPE_QUALS (TREE_TYPE (datum));
1941           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1942
1943           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1944                         NULL_TREE);
1945           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1946             TREE_READONLY (ref) = 1;
1947           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1948             TREE_THIS_VOLATILE (ref) = 1;
1949
1950           if (TREE_DEPRECATED (subdatum))
1951             warn_deprecated_use (subdatum);
1952
1953           datum = ref;
1954
1955           field = TREE_CHAIN (field);
1956         }
1957       while (field);
1958
1959       return ref;
1960     }
1961   else if (code != ERROR_MARK)
1962     error ("request for member %qE in something not a structure or union",
1963            component);
1964
1965   return error_mark_node;
1966 }
1967 \f
1968 /* Given an expression PTR for a pointer, return an expression
1969    for the value pointed to.
1970    ERRORSTRING is the name of the operator to appear in error messages.  */
1971
1972 tree
1973 build_indirect_ref (tree ptr, const char *errorstring)
1974 {
1975   tree pointer = default_conversion (ptr);
1976   tree type = TREE_TYPE (pointer);
1977
1978   if (TREE_CODE (type) == POINTER_TYPE)
1979     {
1980       if (CONVERT_EXPR_P (pointer)
1981           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1982         {
1983           /* If a warning is issued, mark it to avoid duplicates from
1984              the backend.  This only needs to be done at
1985              warn_strict_aliasing > 2.  */
1986           if (warn_strict_aliasing > 2)
1987             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1988                                          type, TREE_OPERAND (pointer, 0)))
1989               TREE_NO_WARNING (pointer) = 1;
1990         }
1991
1992       if (TREE_CODE (pointer) == ADDR_EXPR
1993           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1994               == TREE_TYPE (type)))
1995         return TREE_OPERAND (pointer, 0);
1996       else
1997         {
1998           tree t = TREE_TYPE (type);
1999           tree ref;
2000
2001           ref = build1 (INDIRECT_REF, t, pointer);
2002
2003           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2004             {
2005               error ("dereferencing pointer to incomplete type");
2006               return error_mark_node;
2007             }
2008           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2009             warning (0, "dereferencing %<void *%> pointer");
2010
2011           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2012              so that we get the proper error message if the result is used
2013              to assign to.  Also, &* is supposed to be a no-op.
2014              And ANSI C seems to specify that the type of the result
2015              should be the const type.  */
2016           /* A de-reference of a pointer to const is not a const.  It is valid
2017              to change it via some other pointer.  */
2018           TREE_READONLY (ref) = TYPE_READONLY (t);
2019           TREE_SIDE_EFFECTS (ref)
2020             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2021           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2022           return ref;
2023         }
2024     }
2025   else if (TREE_CODE (pointer) != ERROR_MARK)
2026     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2027   return error_mark_node;
2028 }
2029
2030 /* This handles expressions of the form "a[i]", which denotes
2031    an array reference.
2032
2033    This is logically equivalent in C to *(a+i), but we may do it differently.
2034    If A is a variable or a member, we generate a primitive ARRAY_REF.
2035    This avoids forcing the array out of registers, and can work on
2036    arrays that are not lvalues (for example, members of structures returned
2037    by functions).  */
2038
2039 tree
2040 build_array_ref (tree array, tree index)
2041 {
2042   bool swapped = false;
2043   if (TREE_TYPE (array) == error_mark_node
2044       || TREE_TYPE (index) == error_mark_node)
2045     return error_mark_node;
2046
2047   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2048       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2049     {
2050       tree temp;
2051       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2052           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2053         {
2054           error ("subscripted value is neither array nor pointer");
2055           return error_mark_node;
2056         }
2057       temp = array;
2058       array = index;
2059       index = temp;
2060       swapped = true;
2061     }
2062
2063   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2064     {
2065       error ("array subscript is not an integer");
2066       return error_mark_node;
2067     }
2068
2069   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2070     {
2071       error ("subscripted value is pointer to function");
2072       return error_mark_node;
2073     }
2074
2075   /* ??? Existing practice has been to warn only when the char
2076      index is syntactically the index, not for char[array].  */
2077   if (!swapped)
2078      warn_array_subscript_with_type_char (index);
2079
2080   /* Apply default promotions *after* noticing character types.  */
2081   index = default_conversion (index);
2082
2083   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2084
2085   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2086     {
2087       tree rval, type;
2088
2089       /* An array that is indexed by a non-constant
2090          cannot be stored in a register; we must be able to do
2091          address arithmetic on its address.
2092          Likewise an array of elements of variable size.  */
2093       if (TREE_CODE (index) != INTEGER_CST
2094           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2095               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2096         {
2097           if (!c_mark_addressable (array))
2098             return error_mark_node;
2099         }
2100       /* An array that is indexed by a constant value which is not within
2101          the array bounds cannot be stored in a register either; because we
2102          would get a crash in store_bit_field/extract_bit_field when trying
2103          to access a non-existent part of the register.  */
2104       if (TREE_CODE (index) == INTEGER_CST
2105           && TYPE_DOMAIN (TREE_TYPE (array))
2106           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2107         {
2108           if (!c_mark_addressable (array))
2109             return error_mark_node;
2110         }
2111
2112       if (pedantic)
2113         {
2114           tree foo = array;
2115           while (TREE_CODE (foo) == COMPONENT_REF)
2116             foo = TREE_OPERAND (foo, 0);
2117           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2118             pedwarn (OPT_pedantic,
2119                      "ISO C forbids subscripting %<register%> array");
2120           else if (!flag_isoc99 && !lvalue_p (foo))
2121             pedwarn (OPT_pedantic,
2122                      "ISO C90 forbids subscripting non-lvalue array");
2123         }
2124
2125       type = TREE_TYPE (TREE_TYPE (array));
2126       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2127       /* Array ref is const/volatile if the array elements are
2128          or if the array is.  */
2129       TREE_READONLY (rval)
2130         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2131             | TREE_READONLY (array));
2132       TREE_SIDE_EFFECTS (rval)
2133         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2134             | TREE_SIDE_EFFECTS (array));
2135       TREE_THIS_VOLATILE (rval)
2136         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2137             /* This was added by rms on 16 Nov 91.
2138                It fixes  vol struct foo *a;  a->elts[1]
2139                in an inline function.
2140                Hope it doesn't break something else.  */
2141             | TREE_THIS_VOLATILE (array));
2142       return require_complete_type (fold (rval));
2143     }
2144   else
2145     {
2146       tree ar = default_conversion (array);
2147
2148       if (ar == error_mark_node)
2149         return ar;
2150
2151       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2152       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2153
2154       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2155                                  "array indexing");
2156     }
2157 }
2158 \f
2159 /* Build an external reference to identifier ID.  FUN indicates
2160    whether this will be used for a function call.  LOC is the source
2161    location of the identifier.  */
2162 tree
2163 build_external_ref (tree id, int fun, location_t loc)
2164 {
2165   tree ref;
2166   tree decl = lookup_name (id);
2167
2168   /* In Objective-C, an instance variable (ivar) may be preferred to
2169      whatever lookup_name() found.  */
2170   decl = objc_lookup_ivar (decl, id);
2171
2172   if (decl && decl != error_mark_node)
2173     ref = decl;
2174   else if (fun)
2175     /* Implicit function declaration.  */
2176     ref = implicitly_declare (id);
2177   else if (decl == error_mark_node)
2178     /* Don't complain about something that's already been
2179        complained about.  */
2180     return error_mark_node;
2181   else
2182     {
2183       undeclared_variable (id, loc);
2184       return error_mark_node;
2185     }
2186
2187   if (TREE_TYPE (ref) == error_mark_node)
2188     return error_mark_node;
2189
2190   if (TREE_DEPRECATED (ref))
2191     warn_deprecated_use (ref);
2192
2193   /* Recursive call does not count as usage.  */
2194   if (ref != current_function_decl)
2195     {
2196       TREE_USED (ref) = 1;
2197     }
2198
2199   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2200     {
2201       if (!in_sizeof && !in_typeof)
2202         C_DECL_USED (ref) = 1;
2203       else if (DECL_INITIAL (ref) == 0
2204                && DECL_EXTERNAL (ref)
2205                && !TREE_PUBLIC (ref))
2206         record_maybe_used_decl (ref);
2207     }
2208
2209   if (TREE_CODE (ref) == CONST_DECL)
2210     {
2211       used_types_insert (TREE_TYPE (ref));
2212       ref = DECL_INITIAL (ref);
2213       TREE_CONSTANT (ref) = 1;
2214     }
2215   else if (current_function_decl != 0
2216            && !DECL_FILE_SCOPE_P (current_function_decl)
2217            && (TREE_CODE (ref) == VAR_DECL
2218                || TREE_CODE (ref) == PARM_DECL
2219                || TREE_CODE (ref) == FUNCTION_DECL))
2220     {
2221       tree context = decl_function_context (ref);
2222
2223       if (context != 0 && context != current_function_decl)
2224         DECL_NONLOCAL (ref) = 1;
2225     }
2226   /* C99 6.7.4p3: An inline definition of a function with external
2227      linkage ... shall not contain a reference to an identifier with
2228      internal linkage.  */
2229   else if (current_function_decl != 0
2230            && DECL_DECLARED_INLINE_P (current_function_decl)
2231            && DECL_EXTERNAL (current_function_decl)
2232            && VAR_OR_FUNCTION_DECL_P (ref)
2233            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2234            && ! TREE_PUBLIC (ref)
2235            && DECL_CONTEXT (ref) != current_function_decl)
2236     pedwarn (0, "%H%qD is static but used in inline function %qD "
2237               "which is not static", &loc, ref, current_function_decl);
2238
2239   return ref;
2240 }
2241
2242 /* Record details of decls possibly used inside sizeof or typeof.  */
2243 struct maybe_used_decl
2244 {
2245   /* The decl.  */
2246   tree decl;
2247   /* The level seen at (in_sizeof + in_typeof).  */
2248   int level;
2249   /* The next one at this level or above, or NULL.  */
2250   struct maybe_used_decl *next;
2251 };
2252
2253 static struct maybe_used_decl *maybe_used_decls;
2254
2255 /* Record that DECL, an undefined static function reference seen
2256    inside sizeof or typeof, might be used if the operand of sizeof is
2257    a VLA type or the operand of typeof is a variably modified
2258    type.  */
2259
2260 static void
2261 record_maybe_used_decl (tree decl)
2262 {
2263   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2264   t->decl = decl;
2265   t->level = in_sizeof + in_typeof;
2266   t->next = maybe_used_decls;
2267   maybe_used_decls = t;
2268 }
2269
2270 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2271    USED is false, just discard them.  If it is true, mark them used
2272    (if no longer inside sizeof or typeof) or move them to the next
2273    level up (if still inside sizeof or typeof).  */
2274
2275 void
2276 pop_maybe_used (bool used)
2277 {
2278   struct maybe_used_decl *p = maybe_used_decls;
2279   int cur_level = in_sizeof + in_typeof;
2280   while (p && p->level > cur_level)
2281     {
2282       if (used)
2283         {
2284           if (cur_level == 0)
2285             C_DECL_USED (p->decl) = 1;
2286           else
2287             p->level = cur_level;
2288         }
2289       p = p->next;
2290     }
2291   if (!used || cur_level == 0)
2292     maybe_used_decls = p;
2293 }
2294
2295 /* Return the result of sizeof applied to EXPR.  */
2296
2297 struct c_expr
2298 c_expr_sizeof_expr (struct c_expr expr)
2299 {
2300   struct c_expr ret;
2301   if (expr.value == error_mark_node)
2302     {
2303       ret.value = error_mark_node;
2304       ret.original_code = ERROR_MARK;
2305       pop_maybe_used (false);
2306     }
2307   else
2308     {
2309       ret.value = c_sizeof (TREE_TYPE (expr.value));
2310       ret.original_code = ERROR_MARK;
2311       if (c_vla_type_p (TREE_TYPE (expr.value)))
2312         {
2313           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2314           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2315         }
2316       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2317     }
2318   return ret;
2319 }
2320
2321 /* Return the result of sizeof applied to T, a structure for the type
2322    name passed to sizeof (rather than the type itself).  */
2323
2324 struct c_expr
2325 c_expr_sizeof_type (struct c_type_name *t)
2326 {
2327   tree type;
2328   struct c_expr ret;
2329   type = groktypename (t);
2330   ret.value = c_sizeof (type);
2331   ret.original_code = ERROR_MARK;
2332   pop_maybe_used (type != error_mark_node
2333                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2334   return ret;
2335 }
2336
2337 /* Build a function call to function FUNCTION with parameters PARAMS.
2338    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2339    TREE_VALUE of each node is a parameter-expression.
2340    FUNCTION's data type may be a function type or a pointer-to-function.  */
2341
2342 tree
2343 build_function_call (tree function, tree params)
2344 {
2345   tree fntype, fundecl = 0;
2346   tree name = NULL_TREE, result;
2347   tree tem;
2348   int nargs;
2349   tree *argarray;
2350
2351
2352   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2353   STRIP_TYPE_NOPS (function);
2354
2355   /* Convert anything with function type to a pointer-to-function.  */
2356   if (TREE_CODE (function) == FUNCTION_DECL)
2357     {
2358       /* Implement type-directed function overloading for builtins.
2359          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2360          handle all the type checking.  The result is a complete expression
2361          that implements this function call.  */
2362       tem = resolve_overloaded_builtin (function, params);
2363       if (tem)
2364         return tem;
2365
2366       name = DECL_NAME (function);
2367       fundecl = function;
2368     }
2369   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2370     function = function_to_pointer_conversion (function);
2371
2372   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2373      expressions, like those used for ObjC messenger dispatches.  */
2374   function = objc_rewrite_function_call (function, params);
2375
2376   fntype = TREE_TYPE (function);
2377
2378   if (TREE_CODE (fntype) == ERROR_MARK)
2379     return error_mark_node;
2380
2381   if (!(TREE_CODE (fntype) == POINTER_TYPE
2382         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2383     {
2384       error ("called object %qE is not a function", function);
2385       return error_mark_node;
2386     }
2387
2388   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2389     current_function_returns_abnormally = 1;
2390
2391   /* fntype now gets the type of function pointed to.  */
2392   fntype = TREE_TYPE (fntype);
2393
2394   /* Check that the function is called through a compatible prototype.
2395      If it is not, replace the call by a trap, wrapped up in a compound
2396      expression if necessary.  This has the nice side-effect to prevent
2397      the tree-inliner from generating invalid assignment trees which may
2398      blow up in the RTL expander later.  */
2399   if (CONVERT_EXPR_P (function)
2400       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2401       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2402       && !comptypes (fntype, TREE_TYPE (tem)))
2403     {
2404       tree return_type = TREE_TYPE (fntype);
2405       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2406                                        NULL_TREE);
2407
2408       /* This situation leads to run-time undefined behavior.  We can't,
2409          therefore, simply error unless we can prove that all possible
2410          executions of the program must execute the code.  */
2411       if (warning (0, "function called through a non-compatible type"))
2412         /* We can, however, treat "undefined" any way we please.
2413            Call abort to encourage the user to fix the program.  */
2414         inform ("if this code is reached, the program will abort");
2415
2416       if (VOID_TYPE_P (return_type))
2417         return trap;
2418       else
2419         {
2420           tree rhs;
2421
2422           if (AGGREGATE_TYPE_P (return_type))
2423             rhs = build_compound_literal (return_type,
2424                                           build_constructor (return_type, 0));
2425           else
2426             rhs = fold_convert (return_type, integer_zero_node);
2427
2428           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2429         }
2430     }
2431
2432   /* Convert the parameters to the types declared in the
2433      function prototype, or apply default promotions.  */
2434
2435   nargs = list_length (params);
2436   argarray = (tree *) alloca (nargs * sizeof (tree));
2437   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2438                              params, function, fundecl);
2439   if (nargs < 0)
2440     return error_mark_node;
2441
2442   /* Check that arguments to builtin functions match the expectations.  */
2443   if (fundecl
2444       && DECL_BUILT_IN (fundecl)
2445       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2446       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2447     return error_mark_node;
2448
2449   /* Check that the arguments to the function are valid.  */
2450   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2451                             TYPE_ARG_TYPES (fntype));
2452
2453   if (require_constant_value)
2454     {
2455       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2456                                                   function, nargs, argarray);
2457       if (TREE_CONSTANT (result)
2458           && (name == NULL_TREE
2459               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2460         pedwarn_init (0, "initializer element is not constant");
2461     }
2462   else
2463     result = fold_build_call_array (TREE_TYPE (fntype),
2464                                     function, nargs, argarray);
2465
2466   if (VOID_TYPE_P (TREE_TYPE (result)))
2467     return result;
2468   return require_complete_type (result);
2469 }
2470 \f
2471 /* Convert the argument expressions in the list VALUES
2472    to the types in the list TYPELIST.  The resulting arguments are
2473    stored in the array ARGARRAY which has size NARGS.
2474
2475    If TYPELIST is exhausted, or when an element has NULL as its type,
2476    perform the default conversions.
2477
2478    PARMLIST is the chain of parm decls for the function being called.
2479    It may be 0, if that info is not available.
2480    It is used only for generating error messages.
2481
2482    FUNCTION is a tree for the called function.  It is used only for
2483    error messages, where it is formatted with %qE.
2484
2485    This is also where warnings about wrong number of args are generated.
2486
2487    VALUES is a chain of TREE_LIST nodes with the elements of the list
2488    in the TREE_VALUE slots of those nodes.
2489
2490    Returns the actual number of arguments processed (which may be less
2491    than NARGS in some error situations), or -1 on failure.  */
2492
2493 static int
2494 convert_arguments (int nargs, tree *argarray,
2495                    tree typelist, tree values, tree function, tree fundecl)
2496 {
2497   tree typetail, valtail;
2498   int parmnum;
2499   const bool type_generic = fundecl
2500     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2501   tree selector;
2502
2503   /* Change pointer to function to the function itself for
2504      diagnostics.  */
2505   if (TREE_CODE (function) == ADDR_EXPR
2506       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2507     function = TREE_OPERAND (function, 0);
2508
2509   /* Handle an ObjC selector specially for diagnostics.  */
2510   selector = objc_message_selector ();
2511
2512   /* Scan the given expressions and types, producing individual
2513      converted arguments and storing them in ARGARRAY.  */
2514
2515   for (valtail = values, typetail = typelist, parmnum = 0;
2516        valtail;
2517        valtail = TREE_CHAIN (valtail), parmnum++)
2518     {
2519       tree type = typetail ? TREE_VALUE (typetail) : 0;
2520       tree val = TREE_VALUE (valtail);
2521       tree rname = function;
2522       int argnum = parmnum + 1;
2523       const char *invalid_func_diag;
2524
2525       if (type == void_type_node)
2526         {
2527           error ("too many arguments to function %qE", function);
2528           return parmnum;
2529         }
2530
2531       if (selector && argnum > 2)
2532         {
2533           rname = selector;
2534           argnum -= 2;
2535         }
2536
2537       STRIP_TYPE_NOPS (val);
2538
2539       val = require_complete_type (val);
2540
2541       if (type != 0)
2542         {
2543           /* Formal parm type is specified by a function prototype.  */
2544           tree parmval;
2545
2546           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2547             {
2548               error ("type of formal parameter %d is incomplete", parmnum + 1);
2549               parmval = val;
2550             }
2551           else
2552             {
2553               /* Optionally warn about conversions that
2554                  differ from the default conversions.  */
2555               if (warn_traditional_conversion || warn_traditional)
2556                 {
2557                   unsigned int formal_prec = TYPE_PRECISION (type);
2558
2559                   if (INTEGRAL_TYPE_P (type)
2560                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2561                     warning (0, "passing argument %d of %qE as integer "
2562                              "rather than floating due to prototype",
2563                              argnum, rname);
2564                   if (INTEGRAL_TYPE_P (type)
2565                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2566                     warning (0, "passing argument %d of %qE as integer "
2567                              "rather than complex due to prototype",
2568                              argnum, rname);
2569                   else if (TREE_CODE (type) == COMPLEX_TYPE
2570                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2571                     warning (0, "passing argument %d of %qE as complex "
2572                              "rather than floating due to prototype",
2573                              argnum, rname);
2574                   else if (TREE_CODE (type) == REAL_TYPE
2575                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2576                     warning (0, "passing argument %d of %qE as floating "
2577                              "rather than integer due to prototype",
2578                              argnum, rname);
2579                   else if (TREE_CODE (type) == COMPLEX_TYPE
2580                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2581                     warning (0, "passing argument %d of %qE as complex "
2582                              "rather than integer due to prototype",
2583                              argnum, rname);
2584                   else if (TREE_CODE (type) == REAL_TYPE
2585                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2586                     warning (0, "passing argument %d of %qE as floating "
2587                              "rather than complex due to prototype",
2588                              argnum, rname);
2589                   /* ??? At some point, messages should be written about
2590                      conversions between complex types, but that's too messy
2591                      to do now.  */
2592                   else if (TREE_CODE (type) == REAL_TYPE
2593                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2594                     {
2595                       /* Warn if any argument is passed as `float',
2596                          since without a prototype it would be `double'.  */
2597                       if (formal_prec == TYPE_PRECISION (float_type_node)
2598                           && type != dfloat32_type_node)
2599                         warning (0, "passing argument %d of %qE as %<float%> "
2600                                  "rather than %<double%> due to prototype",
2601                                  argnum, rname);
2602
2603                       /* Warn if mismatch between argument and prototype
2604                          for decimal float types.  Warn of conversions with
2605                          binary float types and of precision narrowing due to
2606                          prototype. */
2607                       else if (type != TREE_TYPE (val)
2608                                && (type == dfloat32_type_node
2609                                    || type == dfloat64_type_node
2610                                    || type == dfloat128_type_node
2611                                    || TREE_TYPE (val) == dfloat32_type_node
2612                                    || TREE_TYPE (val) == dfloat64_type_node
2613                                    || TREE_TYPE (val) == dfloat128_type_node)
2614                                && (formal_prec
2615                                    <= TYPE_PRECISION (TREE_TYPE (val))
2616                                    || (type == dfloat128_type_node
2617                                        && (TREE_TYPE (val)
2618                                            != dfloat64_type_node
2619                                            && (TREE_TYPE (val)
2620                                                != dfloat32_type_node)))
2621                                    || (type == dfloat64_type_node
2622                                        && (TREE_TYPE (val)
2623                                            != dfloat32_type_node))))
2624                         warning (0, "passing argument %d of %qE as %qT "
2625                                  "rather than %qT due to prototype",
2626                                  argnum, rname, type, TREE_TYPE (val));
2627
2628                     }
2629                   /* Detect integer changing in width or signedness.
2630                      These warnings are only activated with
2631                      -Wtraditional-conversion, not with -Wtraditional.  */
2632                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2633                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2634                     {
2635                       tree would_have_been = default_conversion (val);
2636                       tree type1 = TREE_TYPE (would_have_been);
2637
2638                       if (TREE_CODE (type) == ENUMERAL_TYPE
2639                           && (TYPE_MAIN_VARIANT (type)
2640                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2641                         /* No warning if function asks for enum
2642                            and the actual arg is that enum type.  */
2643                         ;
2644                       else if (formal_prec != TYPE_PRECISION (type1))
2645                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2646                                  "with different width due to prototype",
2647                                  argnum, rname);
2648                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2649                         ;
2650                       /* Don't complain if the formal parameter type
2651                          is an enum, because we can't tell now whether
2652                          the value was an enum--even the same enum.  */
2653                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2654                         ;
2655                       else if (TREE_CODE (val) == INTEGER_CST
2656                                && int_fits_type_p (val, type))
2657                         /* Change in signedness doesn't matter
2658                            if a constant value is unaffected.  */
2659                         ;
2660                       /* If the value is extended from a narrower
2661                          unsigned type, it doesn't matter whether we
2662                          pass it as signed or unsigned; the value
2663                          certainly is the same either way.  */
2664                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2665                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2666                         ;
2667                       else if (TYPE_UNSIGNED (type))
2668                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2669                                  "as unsigned due to prototype",
2670                                  argnum, rname);
2671                       else
2672                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2673                                  "as signed due to prototype", argnum, rname);
2674                     }
2675                 }
2676
2677               parmval = convert_for_assignment (type, val, ic_argpass,
2678                                                 fundecl, function,
2679                                                 parmnum + 1);
2680
2681               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2682                   && INTEGRAL_TYPE_P (type)
2683                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2684                 parmval = default_conversion (parmval);
2685             }
2686           argarray[parmnum] = parmval;
2687         }
2688       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2689                && (TYPE_PRECISION (TREE_TYPE (val))
2690                    < TYPE_PRECISION (double_type_node))
2691                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2692         {
2693           if (type_generic)
2694             argarray[parmnum] = val;
2695           else
2696             /* Convert `float' to `double'.  */
2697             argarray[parmnum] = convert (double_type_node, val);
2698         }
2699       else if ((invalid_func_diag =
2700                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2701         {
2702           error (invalid_func_diag);
2703           return -1;
2704         }
2705       else
2706         /* Convert `short' and `char' to full-size `int'.  */
2707         argarray[parmnum] = default_conversion (val);
2708
2709       if (typetail)
2710         typetail = TREE_CHAIN (typetail);
2711     }
2712
2713   gcc_assert (parmnum == nargs);
2714
2715   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2716     {
2717       error ("too few arguments to function %qE", function);
2718       return -1;
2719     }
2720
2721   return parmnum;
2722 }
2723 \f
2724 /* This is the entry point used by the parser to build unary operators
2725    in the input.  CODE, a tree_code, specifies the unary operator, and
2726    ARG is the operand.  For unary plus, the C parser currently uses
2727    CONVERT_EXPR for code.  */
2728
2729 struct c_expr
2730 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2731 {
2732   struct c_expr result;
2733
2734   result.original_code = ERROR_MARK;
2735   result.value = build_unary_op (code, arg.value, 0);
2736
2737   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2738     overflow_warning (result.value);
2739
2740   return result;
2741 }
2742
2743 /* This is the entry point used by the parser to build binary operators
2744    in the input.  CODE, a tree_code, specifies the binary operator, and
2745    ARG1 and ARG2 are the operands.  In addition to constructing the
2746    expression, we check for operands that were written with other binary
2747    operators in a way that is likely to confuse the user.  */
2748
2749 struct c_expr
2750 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2751                         struct c_expr arg2)
2752 {
2753   struct c_expr result;
2754
2755   enum tree_code code1 = arg1.original_code;
2756   enum tree_code code2 = arg2.original_code;
2757
2758   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2759   result.original_code = code;
2760
2761   if (TREE_CODE (result.value) == ERROR_MARK)
2762     return result;
2763
2764   /* Check for cases such as x+y<<z which users are likely
2765      to misinterpret.  */
2766   if (warn_parentheses)
2767     warn_about_parentheses (code, code1, code2);
2768
2769   if (TREE_CODE_CLASS (code1) != tcc_comparison)
2770     warn_logical_operator (code, arg1.value, arg2.value);
2771
2772   /* Warn about comparisons against string literals, with the exception
2773      of testing for equality or inequality of a string literal with NULL.  */
2774   if (code == EQ_EXPR || code == NE_EXPR)
2775     {
2776       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2777           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2778         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2779     }
2780   else if (TREE_CODE_CLASS (code) == tcc_comparison
2781            && (code1 == STRING_CST || code2 == STRING_CST))
2782     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2783
2784   if (TREE_OVERFLOW_P (result.value)
2785       && !TREE_OVERFLOW_P (arg1.value)
2786       && !TREE_OVERFLOW_P (arg2.value))
2787     overflow_warning (result.value);
2788
2789   return result;
2790 }
2791 \f
2792 /* Return a tree for the difference of pointers OP0 and OP1.
2793    The resulting tree has type int.  */
2794
2795 static tree
2796 pointer_diff (tree op0, tree op1)
2797 {
2798   tree restype = ptrdiff_type_node;
2799
2800   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2801   tree con0, con1, lit0, lit1;
2802   tree orig_op1 = op1;
2803
2804   if (TREE_CODE (target_type) == VOID_TYPE)
2805     pedwarn (pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2806              "pointer of type %<void *%> used in subtraction");
2807   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2808     pedwarn (pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2809              "pointer to a function used in subtraction");
2810
2811   /* If the conversion to ptrdiff_type does anything like widening or
2812      converting a partial to an integral mode, we get a convert_expression
2813      that is in the way to do any simplifications.
2814      (fold-const.c doesn't know that the extra bits won't be needed.
2815      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2816      different mode in place.)
2817      So first try to find a common term here 'by hand'; we want to cover
2818      at least the cases that occur in legal static initializers.  */
2819   if (CONVERT_EXPR_P (op0)
2820       && (TYPE_PRECISION (TREE_TYPE (op0))
2821           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2822     con0 = TREE_OPERAND (op0, 0);
2823   else
2824     con0 = op0;
2825   if (CONVERT_EXPR_P (op1)
2826       && (TYPE_PRECISION (TREE_TYPE (op1))
2827           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2828     con1 = TREE_OPERAND (op1, 0);
2829   else
2830     con1 = op1;
2831
2832   if (TREE_CODE (con0) == PLUS_EXPR)
2833     {
2834       lit0 = TREE_OPERAND (con0, 1);
2835       con0 = TREE_OPERAND (con0, 0);
2836     }
2837   else
2838     lit0 = integer_zero_node;
2839
2840   if (TREE_CODE (con1) == PLUS_EXPR)
2841     {
2842       lit1 = TREE_OPERAND (con1, 1);
2843       con1 = TREE_OPERAND (con1, 0);
2844     }
2845   else
2846     lit1 = integer_zero_node;
2847
2848   if (operand_equal_p (con0, con1, 0))
2849     {
2850       op0 = lit0;
2851       op1 = lit1;
2852     }
2853
2854
2855   /* First do the subtraction as integers;
2856      then drop through to build the divide operator.
2857      Do not do default conversions on the minus operator
2858      in case restype is a short type.  */
2859
2860   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2861                          convert (restype, op1), 0);
2862   /* This generates an error if op1 is pointer to incomplete type.  */
2863   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2864     error ("arithmetic on pointer to an incomplete type");
2865
2866   /* This generates an error if op0 is pointer to incomplete type.  */
2867   op1 = c_size_in_bytes (target_type);
2868
2869   /* Divide by the size, in easiest possible way.  */
2870   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2871 }
2872 \f
2873 /* Construct and perhaps optimize a tree representation
2874    for a unary operation.  CODE, a tree_code, specifies the operation
2875    and XARG is the operand.
2876    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2877    the default promotions (such as from short to int).
2878    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2879    allows non-lvalues; this is only used to handle conversion of non-lvalue
2880    arrays to pointers in C99.  */
2881
2882 tree
2883 build_unary_op (enum tree_code code, tree xarg, int flag)
2884 {
2885   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2886   tree arg = xarg;
2887   tree argtype = 0;
2888   enum tree_code typecode;
2889   tree val;
2890   int noconvert = flag;
2891   const char *invalid_op_diag;
2892
2893   if (code != ADDR_EXPR)
2894     arg = require_complete_type (arg);
2895
2896   typecode = TREE_CODE (TREE_TYPE (arg));
2897   if (typecode == ERROR_MARK)
2898     return error_mark_node;
2899   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2900     typecode = INTEGER_TYPE;
2901
2902   if ((invalid_op_diag
2903        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2904     {
2905       error (invalid_op_diag);
2906       return error_mark_node;
2907     }
2908
2909   switch (code)
2910     {
2911     case CONVERT_EXPR:
2912       /* This is used for unary plus, because a CONVERT_EXPR
2913          is enough to prevent anybody from looking inside for
2914          associativity, but won't generate any code.  */
2915       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2916             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2917             || typecode == VECTOR_TYPE))
2918         {
2919           error ("wrong type argument to unary plus");
2920           return error_mark_node;
2921         }
2922       else if (!noconvert)
2923         arg = default_conversion (arg);
2924       arg = non_lvalue (arg);
2925       break;
2926
2927     case NEGATE_EXPR:
2928       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2929             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2930             || typecode == VECTOR_TYPE))
2931         {
2932           error ("wrong type argument to unary minus");
2933           return error_mark_node;
2934         }
2935       else if (!noconvert)
2936         arg = default_conversion (arg);
2937       break;
2938
2939     case BIT_NOT_EXPR:
2940       /* ~ works on integer types and non float vectors. */
2941       if (typecode == INTEGER_TYPE
2942           || (typecode == VECTOR_TYPE
2943               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2944         {
2945           if (!noconvert)
2946             arg = default_conversion (arg);
2947         }
2948       else if (typecode == COMPLEX_TYPE)
2949         {
2950           code = CONJ_EXPR;
2951           pedwarn (OPT_pedantic,
2952                    "ISO C does not support %<~%> for complex conjugation");
2953           if (!noconvert)
2954             arg = default_conversion (arg);
2955         }
2956       else
2957         {
2958           error ("wrong type argument to bit-complement");
2959           return error_mark_node;
2960         }
2961       break;
2962
2963     case ABS_EXPR:
2964       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2965         {
2966           error ("wrong type argument to abs");
2967           return error_mark_node;
2968         }
2969       else if (!noconvert)
2970         arg = default_conversion (arg);
2971       break;
2972
2973     case CONJ_EXPR:
2974       /* Conjugating a real value is a no-op, but allow it anyway.  */
2975       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2976             || typecode == COMPLEX_TYPE))
2977         {
2978           error ("wrong type argument to conjugation");
2979           return error_mark_node;
2980         }
2981       else if (!noconvert)
2982         arg = default_conversion (arg);
2983       break;
2984
2985     case TRUTH_NOT_EXPR:
2986       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
2987           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2988           && typecode != COMPLEX_TYPE)
2989         {
2990           error ("wrong type argument to unary exclamation mark");
2991           return error_mark_node;
2992         }
2993       arg = c_objc_common_truthvalue_conversion (arg);
2994       return invert_truthvalue (arg);
2995
2996     case REALPART_EXPR:
2997       if (TREE_CODE (arg) == COMPLEX_CST)
2998         return TREE_REALPART (arg);
2999       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3000         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3001       else
3002         return arg;
3003
3004     case IMAGPART_EXPR:
3005       if (TREE_CODE (arg) == COMPLEX_CST)
3006         return TREE_IMAGPART (arg);
3007       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3008         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3009       else
3010         return convert (TREE_TYPE (arg), integer_zero_node);
3011
3012     case PREINCREMENT_EXPR:
3013     case POSTINCREMENT_EXPR:
3014     case PREDECREMENT_EXPR:
3015     case POSTDECREMENT_EXPR:
3016
3017       /* Increment or decrement the real part of the value,
3018          and don't change the imaginary part.  */
3019       if (typecode == COMPLEX_TYPE)
3020         {
3021           tree real, imag;
3022
3023           pedwarn (OPT_pedantic, "ISO C does not support %<++%> and %<--%>"
3024                    " on complex types");
3025
3026           arg = stabilize_reference (arg);
3027           real = build_unary_op (REALPART_EXPR, arg, 1);
3028           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3029           real = build_unary_op (code, real, 1);
3030           if (real == error_mark_node || imag == error_mark_node)
3031             return error_mark_node;
3032           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3033                          real, imag);
3034         }
3035
3036       /* Report invalid types.  */
3037
3038       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3039           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3040         {
3041           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3042             error ("wrong type argument to increment");
3043           else
3044             error ("wrong type argument to decrement");
3045
3046           return error_mark_node;
3047         }
3048
3049       {
3050         tree inc;
3051         tree result_type = TREE_TYPE (arg);
3052
3053         arg = get_unwidened (arg, 0);
3054         argtype = TREE_TYPE (arg);
3055
3056         /* Compute the increment.  */
3057
3058         if (typecode == POINTER_TYPE)
3059           {
3060             /* If pointer target is an undefined struct,
3061                we just cannot know how to do the arithmetic.  */
3062             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3063               {
3064                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3065                   error ("increment of pointer to unknown structure");
3066                 else
3067                   error ("decrement of pointer to unknown structure");
3068               }
3069             else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3070                      || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
3071               {
3072                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3073                   pedwarn (pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3074                            "wrong type argument to increment");
3075                 else
3076                   pedwarn (pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3077                            "wrong type argument to decrement");
3078               }
3079
3080             inc = c_size_in_bytes (TREE_TYPE (result_type));
3081             inc = fold_convert (sizetype, inc);
3082           }
3083         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3084           {
3085             /* For signed fract types, we invert ++ to -- or
3086                -- to ++, and change inc from 1 to -1, because
3087                it is not possible to represent 1 in signed fract constants.
3088                For unsigned fract types, the result always overflows and
3089                we get an undefined (original) or the maximum value.  */
3090             if (code == PREINCREMENT_EXPR)
3091               code = PREDECREMENT_EXPR;
3092             else if (code == PREDECREMENT_EXPR)
3093               code = PREINCREMENT_EXPR;
3094             else if (code == POSTINCREMENT_EXPR)
3095               code = POSTDECREMENT_EXPR;
3096             else /* code == POSTDECREMENT_EXPR  */
3097               code = POSTINCREMENT_EXPR;
3098
3099             inc = integer_minus_one_node;
3100             inc = convert (argtype, inc);
3101           }
3102         else
3103           {
3104             inc = integer_one_node;
3105             inc = convert (argtype, inc);
3106           }
3107
3108         /* Complain about anything else that is not a true lvalue.  */
3109         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3110                                     || code == POSTINCREMENT_EXPR)
3111                                    ? lv_increment
3112                                    : lv_decrement)))
3113           return error_mark_node;
3114
3115         /* Report a read-only lvalue.  */
3116         if (TREE_READONLY (arg))
3117           {
3118             readonly_error (arg,
3119                             ((code == PREINCREMENT_EXPR
3120                               || code == POSTINCREMENT_EXPR)
3121                              ? lv_increment : lv_decrement));
3122             return error_mark_node;
3123           }
3124
3125         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3126           val = boolean_increment (code, arg);
3127         else
3128           val = build2 (code, TREE_TYPE (arg), arg, inc);
3129         TREE_SIDE_EFFECTS (val) = 1;
3130         val = convert (result_type, val);
3131         if (TREE_CODE (val) != code)
3132           TREE_NO_WARNING (val) = 1;
3133         return val;
3134       }
3135
3136     case ADDR_EXPR:
3137       /* Note that this operation never does default_conversion.  */
3138
3139       /* Let &* cancel out to simplify resulting code.  */
3140       if (TREE_CODE (arg) == INDIRECT_REF)
3141         {
3142           /* Don't let this be an lvalue.  */
3143           if (lvalue_p (TREE_OPERAND (arg, 0)))
3144             return non_lvalue (TREE_OPERAND (arg, 0));
3145           return TREE_OPERAND (arg, 0);
3146         }
3147
3148       /* For &x[y], return x+y */
3149       if (TREE_CODE (arg) == ARRAY_REF)
3150         {
3151           tree op0 = TREE_OPERAND (arg, 0);
3152           if (!c_mark_addressable (op0))
3153             return error_mark_node;
3154           return build_binary_op (PLUS_EXPR,
3155                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3156                                    ? array_to_pointer_conversion (op0)
3157                                    : op0),
3158                                   TREE_OPERAND (arg, 1), 1);
3159         }
3160
3161       /* Anything not already handled and not a true memory reference
3162          or a non-lvalue array is an error.  */
3163       else if (typecode != FUNCTION_TYPE && !flag
3164                && !lvalue_or_else (arg, lv_addressof))
3165         return error_mark_node;
3166
3167       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3168       argtype = TREE_TYPE (arg);
3169
3170       /* If the lvalue is const or volatile, merge that into the type
3171          to which the address will point.  Note that you can't get a
3172          restricted pointer by taking the address of something, so we
3173          only have to deal with `const' and `volatile' here.  */
3174       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3175           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3176           argtype = c_build_type_variant (argtype,
3177                                           TREE_READONLY (arg),
3178                                           TREE_THIS_VOLATILE (arg));
3179
3180       if (!c_mark_addressable (arg))
3181         return error_mark_node;
3182
3183       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3184                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3185
3186       argtype = build_pointer_type (argtype);
3187
3188       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3189          when we have proper support for integer constant expressions.  */
3190       val = get_base_address (arg);
3191       if (val && TREE_CODE (val) == INDIRECT_REF
3192           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3193         {
3194           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3195
3196           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3197           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3198         }
3199
3200       val = build1 (ADDR_EXPR, argtype, arg);
3201
3202       return val;
3203
3204     default:
3205       gcc_unreachable ();
3206     }
3207
3208   if (argtype == 0)
3209     argtype = TREE_TYPE (arg);
3210   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3211                                 : fold_build1 (code, argtype, arg);
3212 }
3213
3214 /* Return nonzero if REF is an lvalue valid for this language.
3215    Lvalues can be assigned, unless their type has TYPE_READONLY.
3216    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3217
3218 static int
3219 lvalue_p (const_tree ref)
3220 {
3221   const enum tree_code code = TREE_CODE (ref);
3222
3223   switch (code)
3224     {
3225     case REALPART_EXPR:
3226     case IMAGPART_EXPR:
3227     case COMPONENT_REF:
3228       return lvalue_p (TREE_OPERAND (ref, 0));
3229
3230     case COMPOUND_LITERAL_EXPR:
3231     case STRING_CST:
3232       return 1;
3233
3234     case INDIRECT_REF:
3235     case ARRAY_REF:
3236     case VAR_DECL:
3237     case PARM_DECL:
3238     case RESULT_DECL:
3239     case ERROR_MARK:
3240       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3241               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3242
3243     case BIND_EXPR:
3244       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3245
3246     default:
3247       return 0;
3248     }
3249 }
3250 \f
3251 /* Give an error for storing in something that is 'const'.  */
3252
3253 static void
3254 readonly_error (tree arg, enum lvalue_use use)
3255 {
3256   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3257               || use == lv_asm);
3258   /* Using this macro rather than (for example) arrays of messages
3259      ensures that all the format strings are checked at compile
3260      time.  */
3261 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3262                                    : (use == lv_increment ? (I)         \
3263                                    : (use == lv_decrement ? (D) : (AS))))
3264   if (TREE_CODE (arg) == COMPONENT_REF)
3265     {
3266       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3267         readonly_error (TREE_OPERAND (arg, 0), use);
3268       else
3269         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3270                              G_("increment of read-only member %qD"),
3271                              G_("decrement of read-only member %qD"),
3272                              G_("read-only member %qD used as %<asm%> output")),
3273                TREE_OPERAND (arg, 1));
3274     }
3275   else if (TREE_CODE (arg) == VAR_DECL)
3276     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3277                          G_("increment of read-only variable %qD"),
3278                          G_("decrement of read-only variable %qD"),
3279                          G_("read-only variable %qD used as %<asm%> output")),
3280            arg);
3281   else
3282     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3283                          G_("increment of read-only location %qE"),
3284                          G_("decrement of read-only location %qE"),
3285                          G_("read-only location %qE used as %<asm%> output")),
3286            arg);
3287 }
3288
3289
3290 /* Return nonzero if REF is an lvalue valid for this language;
3291    otherwise, print an error message and return zero.  USE says
3292    how the lvalue is being used and so selects the error message.  */
3293
3294 static int
3295 lvalue_or_else (const_tree ref, enum lvalue_use use)
3296 {
3297   int win = lvalue_p (ref);
3298
3299   if (!win)
3300     lvalue_error (use);
3301
3302   return win;
3303 }
3304 \f
3305 /* Mark EXP saying that we need to be able to take the
3306    address of it; it should not be allocated in a register.
3307    Returns true if successful.  */
3308
3309 bool
3310 c_mark_addressable (tree exp)
3311 {
3312   tree x = exp;
3313
3314   while (1)
3315     switch (TREE_CODE (x))
3316       {
3317       case COMPONENT_REF:
3318         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3319           {
3320             error
3321               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3322             return false;
3323           }
3324
3325         /* ... fall through ...  */
3326
3327       case ADDR_EXPR:
3328       case ARRAY_REF:
3329       case REALPART_EXPR:
3330       case IMAGPART_EXPR:
3331         x = TREE_OPERAND (x, 0);
3332         break;
3333
3334       case COMPOUND_LITERAL_EXPR:
3335       case CONSTRUCTOR:
3336         TREE_ADDRESSABLE (x) = 1;
3337         return true;
3338
3339       case VAR_DECL:
3340       case CONST_DECL:
3341       case PARM_DECL:
3342       case RESULT_DECL:
3343         if (C_DECL_REGISTER (x)
3344             && DECL_NONLOCAL (x))
3345           {
3346             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3347               {
3348                 error
3349                   ("global register variable %qD used in nested function", x);
3350                 return false;
3351               }
3352             pedwarn (0, "register variable %qD used in nested function", x);
3353           }
3354         else if (C_DECL_REGISTER (x))
3355           {
3356             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3357               error ("address of global register variable %qD requested", x);
3358             else
3359               error ("address of register variable %qD requested", x);
3360             return false;
3361           }
3362
3363         /* drops in */
3364       case FUNCTION_DECL:
3365         TREE_ADDRESSABLE (x) = 1;
3366         /* drops out */
3367       default:
3368         return true;
3369     }
3370 }
3371 \f
3372 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3373
3374 tree
3375 build_conditional_expr (tree ifexp, tree op1, tree op2)
3376 {
3377   tree type1;
3378   tree type2;
3379   enum tree_code code1;
3380   enum tree_code code2;
3381   tree result_type = NULL;
3382   tree orig_op1 = op1, orig_op2 = op2;
3383
3384   /* Promote both alternatives.  */
3385
3386   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3387     op1 = default_conversion (op1);
3388   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3389     op2 = default_conversion (op2);
3390
3391   if (TREE_CODE (ifexp) == ERROR_MARK
3392       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3393       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3394     return error_mark_node;
3395
3396   type1 = TREE_TYPE (op1);
3397   code1 = TREE_CODE (type1);
3398   type2 = TREE_TYPE (op2);
3399   code2 = TREE_CODE (type2);
3400
3401   /* C90 does not permit non-lvalue arrays in conditional expressions.
3402      In C99 they will be pointers by now.  */
3403   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3404     {
3405       error ("non-lvalue array in conditional expression");
3406       return error_mark_node;
3407     }
3408
3409   /* Quickly detect the usual case where op1 and op2 have the same type
3410      after promotion.  */
3411   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3412     {
3413       if (type1 == type2)
3414         result_type = type1;
3415       else
3416         result_type = TYPE_MAIN_VARIANT (type1);
3417     }
3418   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3419             || code1 == COMPLEX_TYPE)
3420            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3421                || code2 == COMPLEX_TYPE))
3422     {
3423       result_type = c_common_type (type1, type2);
3424
3425       /* If -Wsign-compare, warn here if type1 and type2 have
3426          different signedness.  We'll promote the signed to unsigned
3427          and later code won't know it used to be different.
3428          Do this check on the original types, so that explicit casts
3429          will be considered, but default promotions won't.  */
3430       if (warn_sign_compare && !skip_evaluation)
3431         {
3432           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3433           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3434
3435           if (unsigned_op1 ^ unsigned_op2)
3436             {
3437               bool ovf;
3438
3439               /* Do not warn if the result type is signed, since the
3440                  signed type will only be chosen if it can represent
3441                  all the values of the unsigned type.  */
3442               if (!TYPE_UNSIGNED (result_type))
3443                 /* OK */;
3444               /* Do not warn if the signed quantity is an unsuffixed
3445                  integer literal (or some static constant expression
3446                  involving such literals) and it is non-negative.  */
3447               else if ((unsigned_op2
3448                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3449                        || (unsigned_op1
3450                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3451                 /* OK */;
3452               else
3453                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3454             }
3455         }
3456     }
3457   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3458     {
3459       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3460         pedwarn (OPT_pedantic,
3461                  "ISO C forbids conditional expr with only one void side");
3462       result_type = void_type_node;
3463     }
3464   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3465     {
3466       if (comp_target_types (type1, type2))
3467         result_type = common_pointer_type (type1, type2);
3468       else if (null_pointer_constant_p (orig_op1))
3469         result_type = qualify_type (type2, type1);
3470       else if (null_pointer_constant_p (orig_op2))
3471         result_type = qualify_type (type1, type2);
3472       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3473         {
3474           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3475             pedwarn (OPT_pedantic, "ISO C forbids conditional expr between "
3476                      "%<void *%> and function pointer");
3477           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3478                                                           TREE_TYPE (type2)));
3479         }
3480       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3481         {
3482           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3483             pedwarn (OPT_pedantic, "ISO C forbids conditional expr between "
3484                      "%<void *%> and function pointer");
3485           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3486                                                           TREE_TYPE (type1)));
3487         }
3488       else
3489         {
3490           pedwarn (0, "pointer type mismatch in conditional expression");
3491           result_type = build_pointer_type (void_type_node);
3492         }
3493     }
3494   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3495     {
3496       if (!null_pointer_constant_p (orig_op2))
3497         pedwarn (0, "pointer/integer type mismatch in conditional expression");
3498       else
3499         {
3500           op2 = null_pointer_node;
3501         }
3502       result_type = type1;
3503     }
3504   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3505     {
3506       if (!null_pointer_constant_p (orig_op1))
3507         pedwarn (0, "pointer/integer type mismatch in conditional expression");
3508       else
3509         {
3510           op1 = null_pointer_node;
3511         }
3512       result_type = type2;
3513     }
3514
3515   if (!result_type)
3516     {
3517       if (flag_cond_mismatch)
3518         result_type = void_type_node;
3519       else
3520         {
3521           error ("type mismatch in conditional expression");
3522           return error_mark_node;
3523         }
3524     }
3525
3526   /* Merge const and volatile flags of the incoming types.  */
3527   result_type
3528     = build_type_variant (result_type,
3529                           TREE_READONLY (op1) || TREE_READONLY (op2),
3530                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3531
3532   if (result_type != TREE_TYPE (op1))
3533     op1 = convert_and_check (result_type, op1);
3534   if (result_type != TREE_TYPE (op2))
3535     op2 = convert_and_check (result_type, op2);
3536
3537   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3538 }
3539 \f
3540 /* Return a compound expression that performs two expressions and
3541    returns the value of the second of them.  */
3542
3543 tree
3544 build_compound_expr (tree expr1, tree expr2)
3545 {
3546   if (!TREE_SIDE_EFFECTS (expr1))
3547     {
3548       /* The left-hand operand of a comma expression is like an expression
3549          statement: with -Wunused, we should warn if it doesn't have
3550          any side-effects, unless it was explicitly cast to (void).  */
3551       if (warn_unused_value)
3552         {
3553           if (VOID_TYPE_P (TREE_TYPE (expr1))
3554               && CONVERT_EXPR_P (expr1))
3555             ; /* (void) a, b */
3556           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3557                    && TREE_CODE (expr1) == COMPOUND_EXPR
3558                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3559             ; /* (void) a, (void) b, c */
3560           else
3561             warning (OPT_Wunused_value,
3562                      "left-hand operand of comma expression has no effect");
3563         }
3564     }
3565
3566   /* With -Wunused, we should also warn if the left-hand operand does have
3567      side-effects, but computes a value which is not used.  For example, in
3568      `foo() + bar(), baz()' the result of the `+' operator is not used,
3569      so we should issue a warning.  */
3570   else if (warn_unused_value)
3571     warn_if_unused_value (expr1, input_location);
3572
3573   if (expr2 == error_mark_node)
3574     return error_mark_node;
3575
3576   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3577 }
3578
3579 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3580
3581 tree
3582 build_c_cast (tree type, tree expr)
3583 {
3584   tree value = expr;
3585
3586   if (type == error_mark_node || expr == error_mark_node)
3587     return error_mark_node;
3588
3589   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3590      only in <protocol> qualifications.  But when constructing cast expressions,
3591      the protocols do matter and must be kept around.  */
3592   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3593     return build1 (NOP_EXPR, type, expr);
3594
3595   type = TYPE_MAIN_VARIANT (type);
3596
3597   if (TREE_CODE (type) == ARRAY_TYPE)
3598     {
3599       error ("cast specifies array type");
3600       return error_mark_node;
3601     }
3602
3603   if (TREE_CODE (type) == FUNCTION_TYPE)
3604     {
3605       error ("cast specifies function type");
3606       return error_mark_node;
3607     }
3608
3609   if (!VOID_TYPE_P (type))
3610     {
3611       value = require_complete_type (value);
3612       if (value == error_mark_node)
3613         return error_mark_node;
3614     }
3615
3616   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3617     {
3618       if (TREE_CODE (type) == RECORD_TYPE
3619           || TREE_CODE (type) == UNION_TYPE)
3620         pedwarn (OPT_pedantic,
3621                  "ISO C forbids casting nonscalar to the same type");
3622     }
3623   else if (TREE_CODE (type) == UNION_TYPE)
3624     {
3625       tree field;
3626
3627       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3628         if (TREE_TYPE (field) != error_mark_node
3629             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3630                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3631           break;
3632
3633       if (field)
3634         {
3635           tree t;
3636
3637           pedwarn (OPT_pedantic, "ISO C forbids casts to union type");
3638           t = digest_init (type,
3639                            build_constructor_single (type, field, value),
3640                            true, 0);
3641           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3642           return t;
3643         }
3644       error ("cast to union type from type not present in union");
3645       return error_mark_node;
3646     }
3647   else
3648     {
3649       tree otype, ovalue;
3650
3651       if (type == void_type_node)
3652         return build1 (CONVERT_EXPR, type, value);
3653
3654       otype = TREE_TYPE (value);
3655
3656       /* Optionally warn about potentially worrisome casts.  */
3657
3658       if (warn_cast_qual
3659           && TREE_CODE (type) == POINTER_TYPE
3660           && TREE_CODE (otype) == POINTER_TYPE)
3661         {
3662           tree in_type = type;
3663           tree in_otype = otype;
3664           int added = 0;
3665           int discarded = 0;
3666
3667           /* Check that the qualifiers on IN_TYPE are a superset of
3668              the qualifiers of IN_OTYPE.  The outermost level of
3669              POINTER_TYPE nodes is uninteresting and we stop as soon
3670              as we hit a non-POINTER_TYPE node on either type.  */
3671           do
3672             {
3673               in_otype = TREE_TYPE (in_otype);
3674               in_type = TREE_TYPE (in_type);
3675
3676               /* GNU C allows cv-qualified function types.  'const'
3677                  means the function is very pure, 'volatile' means it
3678                  can't return.  We need to warn when such qualifiers
3679                  are added, not when they're taken away.  */
3680               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3681                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3682                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3683               else
3684                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3685             }
3686           while (TREE_CODE (in_type) == POINTER_TYPE
3687                  && TREE_CODE (in_otype) == POINTER_TYPE);
3688
3689           if (added)
3690             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3691
3692           if (discarded)
3693             /* There are qualifiers present in IN_OTYPE that are not
3694                present in IN_TYPE.  */
3695             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3696         }
3697
3698       /* Warn about possible alignment problems.  */
3699       if (STRICT_ALIGNMENT
3700           && TREE_CODE (type) == POINTER_TYPE
3701           && TREE_CODE (otype) == POINTER_TYPE
3702           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3703           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3704           /* Don't warn about opaque types, where the actual alignment
3705              restriction is unknown.  */
3706           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3707                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3708                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3709           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3710         warning (OPT_Wcast_align,
3711                  "cast increases required alignment of target type");
3712
3713       if (TREE_CODE (type) == INTEGER_TYPE
3714           && TREE_CODE (otype) == POINTER_TYPE
3715           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3716       /* Unlike conversion of integers to pointers, where the
3717          warning is disabled for converting constants because
3718          of cases such as SIG_*, warn about converting constant
3719          pointers to integers. In some cases it may cause unwanted
3720          sign extension, and a warning is appropriate.  */
3721         warning (OPT_Wpointer_to_int_cast,
3722                  "cast from pointer to integer of different size");
3723
3724       if (TREE_CODE (value) == CALL_EXPR
3725           && TREE_CODE (type) != TREE_CODE (otype))
3726         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3727                  "to non-matching type %qT", otype, type);
3728
3729       if (TREE_CODE (type) == POINTER_TYPE
3730           && TREE_CODE (otype) == INTEGER_TYPE
3731           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3732           /* Don't warn about converting any constant.  */
3733           && !TREE_CONSTANT (value))
3734         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3735                  "of different size");
3736
3737       if (warn_strict_aliasing <= 2)
3738         strict_aliasing_warning (otype, type, expr);
3739
3740       /* If pedantic, warn for conversions between function and object
3741          pointer types, except for converting a null pointer constant
3742          to function pointer type.  */
3743       if (pedantic
3744           && TREE_CODE (type) == POINTER_TYPE
3745           && TREE_CODE (otype) == POINTER_TYPE
3746           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3747           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3748         pedwarn (OPT_pedantic, "ISO C forbids "
3749                  "conversion of function pointer to object pointer type");
3750
3751       if (pedantic
3752           && TREE_CODE (type) == POINTER_TYPE
3753           && TREE_CODE (otype) == POINTER_TYPE
3754           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3755           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3756           && !null_pointer_constant_p (value))
3757         pedwarn (OPT_pedantic, "ISO C forbids "
3758                  "conversion of object pointer to function pointer type");
3759
3760       ovalue = value;
3761       value = convert (type, value);
3762
3763       /* Ignore any integer overflow caused by the cast.  */
3764       if (TREE_CODE (value) == INTEGER_CST)
3765         {
3766           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3767             {
3768               if (!TREE_OVERFLOW (value))
3769                 {
3770                   /* Avoid clobbering a shared constant.  */
3771                   value = copy_node (value);
3772                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3773                 }
3774             }
3775           else if (TREE_OVERFLOW (value))
3776             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3777             value = build_int_cst_wide (TREE_TYPE (value),
3778                                         TREE_INT_CST_LOW (value),
3779                                         TREE_INT_CST_HIGH (value));
3780         }
3781     }
3782
3783   /* Don't let a cast be an lvalue.  */
3784   if (value == expr)
3785     value = non_lvalue (value);
3786
3787   return value;
3788 }
3789
3790 /* Interpret a cast of expression EXPR to type TYPE.  */
3791 tree
3792 c_cast_expr (struct c_type_name *type_name, tree expr)
3793 {
3794   tree type;
3795   int saved_wsp = warn_strict_prototypes;
3796
3797   /* This avoids warnings about unprototyped casts on
3798      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3799   if (TREE_CODE (expr) == INTEGER_CST)
3800     warn_strict_prototypes = 0;
3801   type = groktypename (type_name);
3802   warn_strict_prototypes = saved_wsp;
3803
3804   return build_c_cast (type, expr);
3805 }
3806 \f
3807 /* Build an assignment expression of lvalue LHS from value RHS.
3808    MODIFYCODE is the code for a binary operator that we use
3809    to combine the old value of LHS with RHS to get the new value.
3810    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3811
3812 tree
3813 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3814 {
3815   tree result;
3816   tree newrhs;
3817   tree lhstype = TREE_TYPE (lhs);
3818   tree olhstype = lhstype;
3819
3820   /* Types that aren't fully specified cannot be used in assignments.  */
3821   lhs = require_complete_type (lhs);
3822
3823   /* Avoid duplicate error messages from operands that had errors.  */
3824   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3825     return error_mark_node;
3826
3827   if (!lvalue_or_else (lhs, lv_assign))
3828     return error_mark_node;
3829
3830   STRIP_TYPE_NOPS (rhs);
3831
3832   newrhs = rhs;
3833
3834   /* If a binary op has been requested, combine the old LHS value with the RHS
3835      producing the value we should actually store into the LHS.  */
3836
3837   if (modifycode != NOP_EXPR)
3838     {
3839       lhs = stabilize_reference (lhs);
3840       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3841     }
3842
3843   /* Give an error for storing in something that is 'const'.  */
3844
3845   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3846       || ((TREE_CODE (lhstype) == RECORD_TYPE
3847            || TREE_CODE (lhstype) == UNION_TYPE)
3848           && C_TYPE_FIELDS_READONLY (lhstype)))
3849     {
3850       readonly_error (lhs, lv_assign);
3851       return error_mark_node;
3852     }
3853
3854   /* If storing into a structure or union member,
3855      it has probably been given type `int'.
3856      Compute the type that would go with
3857      the actual amount of storage the member occupies.  */
3858
3859   if (TREE_CODE (lhs) == COMPONENT_REF
3860       && (TREE_CODE (lhstype) == INTEGER_TYPE
3861           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3862           || TREE_CODE (lhstype) == REAL_TYPE
3863           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3864     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3865
3866   /* If storing in a field that is in actuality a short or narrower than one,
3867      we must store in the field in its actual type.  */
3868
3869   if (lhstype != TREE_TYPE (lhs))
3870     {
3871       lhs = copy_node (lhs);
3872       TREE_TYPE (lhs) = lhstype;
3873     }
3874
3875   /* Convert new value to destination type.  */
3876
3877   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3878                                    NULL_TREE, NULL_TREE, 0);
3879   if (TREE_CODE (newrhs) == ERROR_MARK)
3880     return error_mark_node;
3881
3882   /* Emit ObjC write barrier, if necessary.  */
3883   if (c_dialect_objc () && flag_objc_gc)
3884     {
3885       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3886       if (result)
3887         return result;
3888     }
3889
3890   /* Scan operands.  */
3891
3892   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3893   TREE_SIDE_EFFECTS (result) = 1;
3894
3895   /* If we got the LHS in a different type for storing in,
3896      convert the result back to the nominal type of LHS
3897      so that the value we return always has the same type
3898      as the LHS argument.  */
3899
3900   if (olhstype == TREE_TYPE (result))
3901     return result;
3902   return convert_for_assignment (olhstype, result, ic_assign,
3903                                  NULL_TREE, NULL_TREE, 0);
3904 }
3905 \f
3906 /* Convert value RHS to type TYPE as preparation for an assignment
3907    to an lvalue of type TYPE.
3908    The real work of conversion is done by `convert'.
3909    The purpose of this function is to generate error messages
3910    for assignments that are not allowed in C.
3911    ERRTYPE says whether it is argument passing, assignment,
3912    initialization or return.
3913
3914    FUNCTION is a tree for the function being called.
3915    PARMNUM is the number of the argument, for printing in error messages.  */
3916
3917 static tree
3918 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3919                         tree fundecl, tree function, int parmnum)
3920 {
3921   enum tree_code codel = TREE_CODE (type);
3922   tree rhstype;
3923   enum tree_code coder;
3924   tree rname = NULL_TREE;
3925   bool objc_ok = false;
3926
3927   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3928     {
3929       tree selector;
3930       /* Change pointer to function to the function itself for
3931          diagnostics.  */
3932       if (TREE_CODE (function) == ADDR_EXPR
3933           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3934         function = TREE_OPERAND (function, 0);
3935
3936       /* Handle an ObjC selector specially for diagnostics.  */
3937       selector = objc_message_selector ();
3938       rname = function;
3939       if (selector && parmnum > 2)
3940         {
3941           rname = selector;
3942           parmnum -= 2;
3943         }
3944     }
3945
3946   /* This macro is used to emit diagnostics to ensure that all format
3947      strings are complete sentences, visible to gettext and checked at
3948      compile time.  */
3949 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3950   do {                                          \
3951     switch (errtype)                            \
3952       {                                         \
3953       case ic_argpass:                          \
3954         pedwarn (0, AR, parmnum, rname);        \
3955         break;                                  \
3956       case ic_argpass_nonproto:                 \
3957         warning (0, AR, parmnum, rname);        \
3958         break;                                  \
3959       case ic_assign:                           \
3960         pedwarn (0, AS);                        \
3961         break;                                  \
3962       case ic_init:                             \
3963         pedwarn (0, IN);                        \
3964         break;                                  \
3965       case ic_return:                           \
3966         pedwarn (0, RE);                        \
3967         break;                                  \
3968       default:                                  \
3969         gcc_unreachable ();                     \
3970       }                                         \
3971   } while (0)
3972
3973   STRIP_TYPE_NOPS (rhs);
3974
3975   if (optimize && TREE_CODE (rhs) == VAR_DECL
3976            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3977     rhs = decl_constant_value_for_broken_optimization (rhs);
3978
3979   rhstype = TREE_TYPE (rhs);
3980   coder = TREE_CODE (rhstype);
3981
3982   if (coder == ERROR_MARK)
3983     return error_mark_node;
3984
3985   if (c_dialect_objc ())
3986     {
3987       int parmno;
3988
3989       switch (errtype)
3990         {
3991         case ic_return:
3992           parmno = 0;
3993           break;
3994
3995         case ic_assign:
3996           parmno = -1;
3997           break;
3998
3999         case ic_init:
4000           parmno = -2;
4001           break;
4002
4003         default:
4004           parmno = parmnum;
4005           break;
4006         }
4007
4008       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4009     }
4010
4011   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4012     return rhs;
4013
4014   if (coder == VOID_TYPE)
4015     {
4016       /* Except for passing an argument to an unprototyped function,
4017          this is a constraint violation.  When passing an argument to
4018          an unprototyped function, it is compile-time undefined;
4019          making it a constraint in that case was rejected in
4020          DR#252.  */
4021       error ("void value not ignored as it ought to be");
4022       return error_mark_node;
4023     }
4024   rhs = require_complete_type (rhs);
4025   if (rhs == error_mark_node)
4026     return error_mark_node;
4027   /* A type converts to a reference to it.
4028      This code doesn't fully support references, it's just for the
4029      special case of va_start and va_copy.  */
4030   if (codel == REFERENCE_TYPE
4031       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4032     {
4033       if (!lvalue_p (rhs))
4034         {
4035           error ("cannot pass rvalue to reference parameter");
4036           return error_mark_node;
4037         }
4038       if (!c_mark_addressable (rhs))
4039         return error_mark_node;
4040       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4041
4042       /* We already know that these two types are compatible, but they
4043          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4044          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4045          likely to be va_list, a typedef to __builtin_va_list, which
4046          is different enough that it will cause problems later.  */
4047       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4048         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4049
4050       rhs = build1 (NOP_EXPR, type, rhs);
4051       return rhs;
4052     }
4053   /* Some types can interconvert without explicit casts.  */
4054   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4055            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4056     return convert (type, rhs);
4057   /* Arithmetic types all interconvert, and enum is treated like int.  */
4058   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4059             || codel == FIXED_POINT_TYPE
4060             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4061             || codel == BOOLEAN_TYPE)
4062            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4063                || coder == FIXED_POINT_TYPE
4064                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4065                || coder == BOOLEAN_TYPE))
4066     return convert_and_check (type, rhs);
4067
4068   /* Aggregates in different TUs might need conversion.  */
4069   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4070       && codel == coder
4071       && comptypes (type, rhstype))
4072     return convert_and_check (type, rhs);
4073
4074   /* Conversion to a transparent union from its member types.
4075      This applies only to function arguments.  */
4076   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4077       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4078     {
4079       tree memb, marginal_memb = NULL_TREE;
4080
4081       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4082         {
4083           tree memb_type = TREE_TYPE (memb);
4084
4085           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4086                          TYPE_MAIN_VARIANT (rhstype)))
4087             break;
4088
4089           if (TREE_CODE (memb_type) != POINTER_TYPE)
4090             continue;
4091
4092           if (coder == POINTER_TYPE)
4093             {
4094               tree ttl = TREE_TYPE (memb_type);
4095               tree ttr = TREE_TYPE (rhstype);
4096
4097               /* Any non-function converts to a [const][volatile] void *
4098                  and vice versa; otherwise, targets must be the same.
4099                  Meanwhile, the lhs target must have all the qualifiers of
4100                  the rhs.  */
4101               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4102                   || comp_target_types (memb_type, rhstype))
4103                 {
4104                   /* If this type won't generate any warnings, use it.  */
4105                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4106                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4107                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4108                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4109                              == TYPE_QUALS (ttr))
4110                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4111                              == TYPE_QUALS (ttl))))
4112                     break;
4113
4114                   /* Keep looking for a better type, but remember this one.  */
4115                   if (!marginal_memb)
4116                     marginal_memb = memb;
4117                 }
4118             }
4119
4120           /* Can convert integer zero to any pointer type.  */
4121           if (null_pointer_constant_p (rhs))
4122             {
4123               rhs = null_pointer_node;
4124               break;
4125             }
4126         }
4127
4128       if (memb || marginal_memb)
4129         {
4130           if (!memb)
4131             {
4132               /* We have only a marginally acceptable member type;
4133                  it needs a warning.  */
4134               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4135               tree ttr = TREE_TYPE (rhstype);
4136
4137               /* Const and volatile mean something different for function
4138                  types, so the usual warnings are not appropriate.  */
4139               if (TREE_CODE (ttr) == FUNCTION_TYPE
4140                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4141                 {
4142                   /* Because const and volatile on functions are
4143                      restrictions that say the function will not do
4144                      certain things, it is okay to use a const or volatile
4145                      function where an ordinary one is wanted, but not
4146                      vice-versa.  */
4147                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4148                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4149                                             "makes qualified function "
4150                                             "pointer from unqualified"),
4151                                          G_("assignment makes qualified "
4152                                             "function pointer from "
4153                                             "unqualified"),
4154                                          G_("initialization makes qualified "
4155                                             "function pointer from "
4156                                             "unqualified"),
4157                                          G_("return makes qualified function "
4158                                             "pointer from unqualified"));
4159                 }
4160               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4161                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4162                                         "qualifiers from pointer target type"),
4163                                      G_("assignment discards qualifiers "
4164                                         "from pointer target type"),
4165                                      G_("initialization discards qualifiers "
4166                                         "from pointer target type"),
4167                                      G_("return discards qualifiers from "
4168                                         "pointer target type"));
4169
4170               memb = marginal_memb;
4171             }
4172
4173           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4174             pedwarn (OPT_pedantic,
4175                      "ISO C prohibits argument conversion to union type");
4176
4177           rhs = fold_convert (TREE_TYPE (memb), rhs);
4178           return build_constructor_single (type, memb, rhs);
4179         }
4180     }
4181
4182   /* Conversions among pointers */
4183   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4184            && (coder == codel))
4185     {
4186       tree ttl = TREE_TYPE (type);
4187       tree ttr = TREE_TYPE (rhstype);
4188       tree mvl = ttl;
4189       tree mvr = ttr;
4190       bool is_opaque_pointer;
4191       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4192
4193       if (TREE_CODE (mvl) != ARRAY_TYPE)
4194         mvl = TYPE_MAIN_VARIANT (mvl);
4195       if (TREE_CODE (mvr) != ARRAY_TYPE)
4196         mvr = TYPE_MAIN_VARIANT (mvr);
4197       /* Opaque pointers are treated like void pointers.  */
4198       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4199
4200       /* C++ does not allow the implicit conversion void* -> T*.  However,
4201          for the purpose of reducing the number of false positives, we
4202          tolerate the special case of
4203
4204                 int *p = NULL;
4205
4206          where NULL is typically defined in C to be '(void *) 0'.  */
4207       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4208         warning (OPT_Wc___compat, "request for implicit conversion from "
4209                  "%qT to %qT not permitted in C++", rhstype, type);
4210
4211       /* Check if the right-hand side has a format attribute but the
4212          left-hand side doesn't.  */
4213       if (warn_missing_format_attribute
4214           && check_missing_format_attribute (type, rhstype))
4215         {
4216           switch (errtype)
4217           {
4218           case ic_argpass:
4219           case ic_argpass_nonproto:
4220             warning (OPT_Wmissing_format_attribute,
4221                      "argument %d of %qE might be "
4222                      "a candidate for a format attribute",
4223                      parmnum, rname);
4224             break;
4225           case ic_assign:
4226             warning (OPT_Wmissing_format_attribute,
4227                      "assignment left-hand side might be "
4228                      "a candidate for a format attribute");
4229             break;
4230           case ic_init:
4231             warning (OPT_Wmissing_format_attribute,
4232                      "initialization left-hand side might be "
4233                      "a candidate for a format attribute");
4234             break;
4235           case ic_return:
4236             warning (OPT_Wmissing_format_attribute,
4237                      "return type might be "
4238                      "a candidate for a format attribute");
4239             break;
4240           default:
4241             gcc_unreachable ();
4242           }
4243         }
4244
4245       /* Any non-function converts to a [const][volatile] void *
4246          and vice versa; otherwise, targets must be the same.
4247          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4248       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4249           || (target_cmp = comp_target_types (type, rhstype))
4250           || is_opaque_pointer
4251           || (c_common_unsigned_type (mvl)
4252               == c_common_unsigned_type (mvr)))
4253         {
4254           if (pedantic
4255               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4256                   ||
4257                   (VOID_TYPE_P (ttr)
4258                    && !null_pointer_constant_p (rhs)
4259                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4260             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4261                                     "%qE between function pointer "
4262                                     "and %<void *%>"),
4263                                  G_("ISO C forbids assignment between "
4264                                     "function pointer and %<void *%>"),
4265                                  G_("ISO C forbids initialization between "
4266                                     "function pointer and %<void *%>"),
4267                                  G_("ISO C forbids return between function "
4268                                     "pointer and %<void *%>"));
4269           /* Const and volatile mean something different for function types,
4270              so the usual warnings are not appropriate.  */
4271           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4272                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4273             {
4274               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4275                 {
4276                   /* Types differing only by the presence of the 'volatile'
4277                      qualifier are acceptable if the 'volatile' has been added
4278                      in by the Objective-C EH machinery.  */
4279                   if (!objc_type_quals_match (ttl, ttr))
4280                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4281                                             "qualifiers from pointer target type"),
4282                                          G_("assignment discards qualifiers "
4283                                             "from pointer target type"),
4284                                          G_("initialization discards qualifiers "
4285                                             "from pointer target type"),
4286                                          G_("return discards qualifiers from "
4287                                             "pointer target type"));
4288                 }
4289               /* If this is not a case of ignoring a mismatch in signedness,
4290                  no warning.  */
4291               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4292                        || target_cmp)
4293                 ;
4294               /* If there is a mismatch, do warn.  */
4295               else if (warn_pointer_sign)
4296                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4297                                         "%d of %qE differ in signedness"),
4298                                      G_("pointer targets in assignment "
4299                                         "differ in signedness"),
4300                                      G_("pointer targets in initialization "
4301                                         "differ in signedness"),
4302                                      G_("pointer targets in return differ "
4303                                         "in signedness"));
4304             }
4305           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4306                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4307             {
4308               /* Because const and volatile on functions are restrictions
4309                  that say the function will not do certain things,
4310                  it is okay to use a const or volatile function
4311                  where an ordinary one is wanted, but not vice-versa.  */
4312               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4313                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4314                                         "qualified function pointer "
4315                                         "from unqualified"),
4316                                      G_("assignment makes qualified function "
4317                                         "pointer from unqualified"),
4318                                      G_("initialization makes qualified "
4319                                         "function pointer from unqualified"),
4320                                      G_("return makes qualified function "
4321                                         "pointer from unqualified"));
4322             }
4323         }
4324       else
4325         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4326         if (!objc_ok)
4327           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4328                                   "incompatible pointer type"),
4329                                G_("assignment from incompatible pointer type"),
4330                                G_("initialization from incompatible "
4331                                   "pointer type"),
4332                                G_("return from incompatible pointer type"));
4333
4334       return convert (type, rhs);
4335     }
4336   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4337     {
4338       /* ??? This should not be an error when inlining calls to
4339          unprototyped functions.  */
4340       error ("invalid use of non-lvalue array");
4341       return error_mark_node;
4342     }
4343   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4344     {
4345       /* An explicit constant 0 can convert to a pointer,
4346          or one that results from arithmetic, even including
4347          a cast to integer type.  */
4348       if (!null_pointer_constant_p (rhs))
4349         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4350                                 "pointer from integer without a cast"),
4351                              G_("assignment makes pointer from integer "
4352                                 "without a cast"),
4353                              G_("initialization makes pointer from "
4354                                 "integer without a cast"),
4355                              G_("return makes pointer from integer "
4356                                 "without a cast"));
4357
4358       return convert (type, rhs);
4359     }
4360   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4361     {
4362       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4363                               "from pointer without a cast"),
4364                            G_("assignment makes integer from pointer "
4365                               "without a cast"),
4366                            G_("initialization makes integer from pointer "
4367                               "without a cast"),
4368                            G_("return makes integer from pointer "
4369                               "without a cast"));
4370       return convert (type, rhs);
4371     }
4372   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4373     return convert (type, rhs);
4374
4375   switch (errtype)
4376     {
4377     case ic_argpass:
4378     case ic_argpass_nonproto:
4379       /* ??? This should not be an error when inlining calls to
4380          unprototyped functions.  */
4381       error ("incompatible type for argument %d of %qE", parmnum, rname);
4382       break;
4383     case ic_assign:
4384       error ("incompatible types in assignment");
4385       break;
4386     case ic_init:
4387       error ("incompatible types in initialization");
4388       break;
4389     case ic_return:
4390       error ("incompatible types in return");
4391       break;
4392     default:
4393       gcc_unreachable ();
4394     }
4395
4396   return error_mark_node;
4397 }
4398 \f
4399 /* If VALUE is a compound expr all of whose expressions are constant, then
4400    return its value.  Otherwise, return error_mark_node.
4401
4402    This is for handling COMPOUND_EXPRs as initializer elements
4403    which is allowed with a warning when -pedantic is specified.  */
4404
4405 static tree
4406 valid_compound_expr_initializer (tree value, tree endtype)
4407 {
4408   if (TREE_CODE (value) == COMPOUND_EXPR)
4409     {
4410       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4411           == error_mark_node)
4412         return error_mark_node;
4413       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4414                                               endtype);
4415     }
4416   else if (!initializer_constant_valid_p (value, endtype))
4417     return error_mark_node;
4418   else
4419     return value;
4420 }
4421 \f
4422 /* Perform appropriate conversions on the initial value of a variable,
4423    store it in the declaration DECL,
4424    and print any error messages that are appropriate.
4425    If the init is invalid, store an ERROR_MARK.  */
4426
4427 void
4428 store_init_value (tree decl, tree init)
4429 {
4430   tree value, type;
4431
4432   /* If variable's type was invalidly declared, just ignore it.  */
4433
4434   type = TREE_TYPE (decl);
4435   if (TREE_CODE (type) == ERROR_MARK)
4436     return;
4437
4438   /* Digest the specified initializer into an expression.  */
4439
4440   value = digest_init (type, init, true, TREE_STATIC (decl));
4441
4442   /* Store the expression if valid; else report error.  */
4443
4444   if (!in_system_header
4445       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4446     warning (OPT_Wtraditional, "traditional C rejects automatic "
4447              "aggregate initialization");
4448
4449   DECL_INITIAL (decl) = value;
4450
4451   /* ANSI wants warnings about out-of-range constant initializers.  */
4452   STRIP_TYPE_NOPS (value);
4453   if (TREE_STATIC (decl))
4454     constant_expression_warning (value);
4455
4456   /* Check if we need to set array size from compound literal size.  */
4457   if (TREE_CODE (type) == ARRAY_TYPE
4458       && TYPE_DOMAIN (type) == 0
4459       && value != error_mark_node)
4460     {
4461       tree inside_init = init;
4462
4463       STRIP_TYPE_NOPS (inside_init);
4464       inside_init = fold (inside_init);
4465
4466       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4467         {
4468           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4469
4470           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4471             {
4472               /* For int foo[] = (int [3]){1}; we need to set array size
4473                  now since later on array initializer will be just the
4474                  brace enclosed list of the compound literal.  */
4475               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4476               TREE_TYPE (decl) = type;
4477               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4478               layout_type (type);
4479               layout_decl (cldecl, 0);
4480             }
4481         }
4482     }
4483 }
4484 \f
4485 /* Methods for storing and printing names for error messages.  */
4486
4487 /* Implement a spelling stack that allows components of a name to be pushed
4488    and popped.  Each element on the stack is this structure.  */
4489
4490 struct spelling
4491 {
4492   int kind;
4493   union
4494     {
4495       unsigned HOST_WIDE_INT i;
4496       const char *s;
4497     } u;
4498 };
4499
4500 #define SPELLING_STRING 1
4501 #define SPELLING_MEMBER 2
4502 #define SPELLING_BOUNDS 3
4503
4504 static struct spelling *spelling;       /* Next stack element (unused).  */
4505 static struct spelling *spelling_base;  /* Spelling stack base.  */
4506 static int spelling_size;               /* Size of the spelling stack.  */
4507
4508 /* Macros to save and restore the spelling stack around push_... functions.
4509    Alternative to SAVE_SPELLING_STACK.  */
4510
4511 #define SPELLING_DEPTH() (spelling - spelling_base)
4512 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4513
4514 /* Push an element on the spelling stack with type KIND and assign VALUE
4515    to MEMBER.  */
4516
4517 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4518 {                                                                       \
4519   int depth = SPELLING_DEPTH ();                                        \
4520                                                                         \
4521   if (depth >= spelling_size)                                           \
4522     {                                                                   \
4523       spelling_size += 10;                                              \
4524       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4525                                   spelling_size);                       \
4526       RESTORE_SPELLING_DEPTH (depth);                                   \
4527     }                                                                   \
4528                                                                         \
4529   spelling->kind = (KIND);                                              \
4530   spelling->MEMBER = (VALUE);                                           \
4531   spelling++;                                                           \
4532 }
4533
4534 /* Push STRING on the stack.  Printed literally.  */
4535
4536 static void
4537 push_string (const char *string)
4538 {
4539   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4540 }
4541
4542 /* Push a member name on the stack.  Printed as '.' STRING.  */
4543
4544 static void
4545 push_member_name (tree decl)
4546 {
4547   const char *const string
4548     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4549   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4550 }
4551
4552 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4553
4554 static void
4555 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4556 {
4557   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4558 }
4559
4560 /* Compute the maximum size in bytes of the printed spelling.  */
4561
4562 static int
4563 spelling_length (void)
4564 {
4565   int size = 0;
4566   struct spelling *p;
4567
4568   for (p = spelling_base; p < spelling; p++)
4569     {
4570       if (p->kind == SPELLING_BOUNDS)
4571         size += 25;
4572       else
4573         size += strlen (p->u.s) + 1;
4574     }
4575
4576   return size;
4577 }
4578
4579 /* Print the spelling to BUFFER and return it.  */
4580
4581 static char *
4582 print_spelling (char *buffer)
4583 {
4584   char *d = buffer;
4585   struct spelling *p;
4586
4587   for (p = spelling_base; p < spelling; p++)
4588     if (p->kind == SPELLING_BOUNDS)
4589       {
4590         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4591         d += strlen (d);
4592       }
4593     else
4594       {
4595         const char *s;
4596         if (p->kind == SPELLING_MEMBER)
4597           *d++ = '.';
4598         for (s = p->u.s; (*d = *s++); d++)
4599           ;
4600       }
4601   *d++ = '\0';
4602   return buffer;
4603 }
4604
4605 /* Issue an error message for a bad initializer component.
4606    MSGID identifies the message.
4607    The component name is taken from the spelling stack.  */
4608
4609 void
4610 error_init (const char *msgid)
4611 {
4612   char *ofwhat;
4613
4614   error ("%s", _(msgid));
4615   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4616   if (*ofwhat)
4617     error ("(near initialization for %qs)", ofwhat);
4618 }
4619
4620 /* Issue a pedantic warning for a bad initializer component.  OPT is
4621    the option OPT_* (from options.h) controlling this warning or 0 if
4622    it is unconditionally given.  MSGID identifies the message.  The
4623    component name is taken from the spelling stack.  */
4624
4625 void
4626 pedwarn_init (int opt, const char *msgid)
4627 {
4628   char *ofwhat;
4629
4630   pedwarn (opt, "%s", _(msgid));
4631   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4632   if (*ofwhat)
4633     pedwarn (opt, "(near initialization for %qs)", ofwhat);
4634 }
4635
4636 /* Issue a warning for a bad initializer component.
4637
4638    OPT is the OPT_W* value corresponding to the warning option that
4639    controls this warning.  MSGID identifies the message.  The
4640    component name is taken from the spelling stack.  */
4641
4642 static void
4643 warning_init (int opt, const char *msgid)
4644 {
4645   char *ofwhat;
4646
4647   warning (opt, "%s", _(msgid));
4648   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4649   if (*ofwhat)
4650     warning (opt, "(near initialization for %qs)", ofwhat);
4651 }
4652 \f
4653 /* If TYPE is an array type and EXPR is a parenthesized string
4654    constant, warn if pedantic that EXPR is being used to initialize an
4655    object of type TYPE.  */
4656
4657 void
4658 maybe_warn_string_init (tree type, struct c_expr expr)
4659 {
4660   if (pedantic
4661       && TREE_CODE (type) == ARRAY_TYPE
4662       && TREE_CODE (expr.value) == STRING_CST
4663       && expr.original_code != STRING_CST)
4664     pedwarn_init (OPT_pedantic,
4665                   "array initialized from parenthesized string constant");
4666 }
4667
4668 /* Digest the parser output INIT as an initializer for type TYPE.
4669    Return a C expression of type TYPE to represent the initial value.
4670
4671    If INIT is a string constant, STRICT_STRING is true if it is
4672    unparenthesized or we should not warn here for it being parenthesized.
4673    For other types of INIT, STRICT_STRING is not used.
4674
4675    REQUIRE_CONSTANT requests an error if non-constant initializers or
4676    elements are seen.  */
4677
4678 static tree
4679 digest_init (tree type, tree init, bool strict_string, int require_constant)
4680 {
4681   enum tree_code code = TREE_CODE (type);
4682   tree inside_init = init;
4683
4684   if (type == error_mark_node
4685       || !init
4686       || init == error_mark_node
4687       || TREE_TYPE (init) == error_mark_node)
4688     return error_mark_node;
4689
4690   STRIP_TYPE_NOPS (inside_init);
4691
4692   inside_init = fold (inside_init);
4693
4694   /* Initialization of an array of chars from a string constant
4695      optionally enclosed in braces.  */
4696
4697   if (code == ARRAY_TYPE && inside_init
4698       && TREE_CODE (inside_init) == STRING_CST)
4699     {
4700       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4701       /* Note that an array could be both an array of character type
4702          and an array of wchar_t if wchar_t is signed char or unsigned
4703          char.  */
4704       bool char_array = (typ1 == char_type_node
4705                          || typ1 == signed_char_type_node
4706                          || typ1 == unsigned_char_type_node);
4707       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4708       bool char16_array = !!comptypes (typ1, char16_type_node);
4709       bool char32_array = !!comptypes (typ1, char32_type_node);
4710
4711       if (char_array || wchar_array || char16_array || char32_array)
4712         {
4713           struct c_expr expr;
4714           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
4715           expr.value = inside_init;
4716           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4717           maybe_warn_string_init (type, expr);
4718
4719           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4720                          TYPE_MAIN_VARIANT (type)))
4721             return inside_init;
4722
4723           if (char_array)
4724             {
4725               if (typ2 != char_type_node)
4726                 {
4727                   error_init ("char-array initialized from wide string");
4728                   return error_mark_node;
4729                 }
4730             }
4731           else
4732             {
4733               if (typ2 == char_type_node)
4734                 {
4735                   error_init ("wide character array initialized from non-wide "
4736                               "string");
4737                   return error_mark_node;
4738                 }
4739               else if (!comptypes(typ1, typ2))
4740                 {
4741                   error_init ("wide character array initialized from "
4742                               "incompatible wide string");
4743                   return error_mark_node;
4744                 }
4745             }
4746
4747           TREE_TYPE (inside_init) = type;
4748           if (TYPE_DOMAIN (type) != 0
4749               && TYPE_SIZE (type) != 0
4750               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4751               /* Subtract the size of a single (possibly wide) character
4752                  because it's ok to ignore the terminating null char
4753                  that is counted in the length of the constant.  */
4754               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4755                                        TREE_STRING_LENGTH (inside_init)
4756                                        - (TYPE_PRECISION (typ1)
4757                                           / BITS_PER_UNIT)))
4758             pedwarn_init (0, "initializer-string for array of chars is too long");
4759
4760           return inside_init;
4761         }
4762       else if (INTEGRAL_TYPE_P (typ1))
4763         {
4764           error_init ("array of inappropriate type initialized "
4765                       "from string constant");
4766           return error_mark_node;
4767         }
4768     }
4769
4770   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4771      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4772      below and handle as a constructor.  */
4773   if (code == VECTOR_TYPE
4774       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4775       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4776       && TREE_CONSTANT (inside_init))
4777     {
4778       if (TREE_CODE (inside_init) == VECTOR_CST
4779           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4780                         TYPE_MAIN_VARIANT (type)))
4781         return inside_init;
4782
4783       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4784         {
4785           unsigned HOST_WIDE_INT ix;
4786           tree value;
4787           bool constant_p = true;
4788
4789           /* Iterate through elements and check if all constructor
4790              elements are *_CSTs.  */
4791           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4792             if (!CONSTANT_CLASS_P (value))
4793               {
4794                 constant_p = false;
4795                 break;
4796               }
4797
4798           if (constant_p)
4799             return build_vector_from_ctor (type,
4800                                            CONSTRUCTOR_ELTS (inside_init));
4801         }
4802     }
4803
4804   if (warn_sequence_point)
4805     verify_sequence_points (inside_init);
4806
4807   /* Any type can be initialized
4808      from an expression of the same type, optionally with braces.  */
4809
4810   if (inside_init && TREE_TYPE (inside_init) != 0
4811       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4812                      TYPE_MAIN_VARIANT (type))
4813           || (code == ARRAY_TYPE
4814               && comptypes (TREE_TYPE (inside_init), type))
4815           || (code == VECTOR_TYPE
4816               && comptypes (TREE_TYPE (inside_init), type))
4817           || (code == POINTER_TYPE
4818               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4819               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4820                             TREE_TYPE (type)))))
4821     {
4822       if (code == POINTER_TYPE)
4823         {
4824           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4825             {
4826               if (TREE_CODE (inside_init) == STRING_CST
4827                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4828                 inside_init = array_to_pointer_conversion (inside_init);
4829               else
4830                 {
4831                   error_init ("invalid use of non-lvalue array");
4832                   return error_mark_node;
4833                 }
4834             }
4835         }
4836
4837       if (code == VECTOR_TYPE)
4838         /* Although the types are compatible, we may require a
4839            conversion.  */
4840         inside_init = convert (type, inside_init);
4841
4842       if (require_constant
4843           && (code == VECTOR_TYPE || !flag_isoc99)
4844           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4845         {
4846           /* As an extension, allow initializing objects with static storage
4847              duration with compound literals (which are then treated just as
4848              the brace enclosed list they contain).  Also allow this for
4849              vectors, as we can only assign them with compound literals.  */
4850           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4851           inside_init = DECL_INITIAL (decl);
4852         }
4853
4854       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4855           && TREE_CODE (inside_init) != CONSTRUCTOR)
4856         {
4857           error_init ("array initialized from non-constant array expression");
4858           return error_mark_node;
4859         }
4860
4861       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4862         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4863
4864       /* Compound expressions can only occur here if -pedantic or
4865          -pedantic-errors is specified.  In the later case, we always want
4866          an error.  In the former case, we simply want a warning.  */
4867       if (require_constant && pedantic
4868           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4869         {
4870           inside_init
4871             = valid_compound_expr_initializer (inside_init,
4872                                                TREE_TYPE (inside_init));
4873           if (inside_init == error_mark_node)
4874             error_init ("initializer element is not constant");
4875           else
4876             pedwarn_init (OPT_pedantic, "initializer element is not constant");
4877           if (flag_pedantic_errors)
4878             inside_init = error_mark_node;
4879         }
4880       else if (require_constant
4881                && !initializer_constant_valid_p (inside_init,
4882                                                  TREE_TYPE (inside_init)))
4883         {
4884           error_init ("initializer element is not constant");
4885           inside_init = error_mark_node;
4886         }
4887
4888       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4889       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4890         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4891                                               NULL_TREE, 0);
4892       return inside_init;
4893     }
4894
4895   /* Handle scalar types, including conversions.  */
4896
4897   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4898       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4899       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4900     {
4901       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4902           && (TREE_CODE (init) == STRING_CST
4903               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4904         init = array_to_pointer_conversion (init);
4905       inside_init
4906         = convert_for_assignment (type, init, ic_init,
4907                                   NULL_TREE, NULL_TREE, 0);
4908
4909       /* Check to see if we have already given an error message.  */
4910       if (inside_init == error_mark_node)
4911         ;
4912       else if (require_constant && !TREE_CONSTANT (inside_init))
4913         {
4914           error_init ("initializer element is not constant");
4915           inside_init = error_mark_node;
4916         }
4917       else if (require_constant
4918                && !initializer_constant_valid_p (inside_init,
4919                                                  TREE_TYPE (inside_init)))
4920         {
4921           error_init ("initializer element is not computable at load time");
4922           inside_init = error_mark_node;
4923         }
4924
4925       return inside_init;
4926     }
4927
4928   /* Come here only for records and arrays.  */
4929
4930   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4931     {
4932       error_init ("variable-sized object may not be initialized");
4933       return error_mark_node;
4934     }
4935
4936   error_init ("invalid initializer");
4937   return error_mark_node;
4938 }
4939 \f
4940 /* Handle initializers that use braces.  */
4941
4942 /* Type of object we are accumulating a constructor for.
4943    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4944 static tree constructor_type;
4945
4946 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4947    left to fill.  */
4948 static tree constructor_fields;
4949
4950 /* For an ARRAY_TYPE, this is the specified index
4951    at which to store the next element we get.  */
4952 static tree constructor_index;
4953
4954 /* For an ARRAY_TYPE, this is the maximum index.  */
4955 static tree constructor_max_index;
4956
4957 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4958 static tree constructor_unfilled_fields;
4959
4960 /* For an ARRAY_TYPE, this is the index of the first element
4961    not yet written out.  */
4962 static tree constructor_unfilled_index;
4963
4964 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4965    This is so we can generate gaps between fields, when appropriate.  */
4966 static tree constructor_bit_index;
4967
4968 /* If we are saving up the elements rather than allocating them,
4969    this is the list of elements so far (in reverse order,
4970    most recent first).  */
4971 static VEC(constructor_elt,gc) *constructor_elements;
4972
4973 /* 1 if constructor should be incrementally stored into a constructor chain,
4974    0 if all the elements should be kept in AVL tree.  */
4975 static int constructor_incremental;
4976
4977 /* 1 if so far this constructor's elements are all compile-time constants.  */
4978 static int constructor_constant;
4979
4980 /* 1 if so far this constructor's elements are all valid address constants.  */
4981 static int constructor_simple;
4982
4983 /* 1 if this constructor is erroneous so far.  */
4984 static int constructor_erroneous;
4985
4986 /* Structure for managing pending initializer elements, organized as an
4987    AVL tree.  */
4988
4989 struct init_node
4990 {
4991   struct init_node *left, *right;
4992   struct init_node *parent;
4993   int balance;
4994   tree purpose;
4995   tree value;
4996 };
4997
4998 /* Tree of pending elements at this constructor level.
4999    These are elements encountered out of order
5000    which belong at places we haven't reached yet in actually
5001    writing the output.
5002    Will never hold tree nodes across GC runs.  */
5003 static struct init_node *constructor_pending_elts;
5004
5005 /* The SPELLING_DEPTH of this constructor.  */
5006 static int constructor_depth;
5007
5008 /* DECL node for which an initializer is being read.
5009    0 means we are reading a constructor expression
5010    such as (struct foo) {...}.  */
5011 static tree constructor_decl;
5012
5013 /* Nonzero if this is an initializer for a top-level decl.  */
5014 static int constructor_top_level;
5015
5016 /* Nonzero if there were any member designators in this initializer.  */
5017 static int constructor_designated;
5018
5019 /* Nesting depth of designator list.  */
5020 static int designator_depth;
5021
5022 /* Nonzero if there were diagnosed errors in this designator list.  */
5023 static int designator_erroneous;
5024
5025 \f
5026 /* This stack has a level for each implicit or explicit level of
5027    structuring in the initializer, including the outermost one.  It
5028    saves the values of most of the variables above.  */
5029
5030 struct constructor_range_stack;
5031
5032 struct constructor_stack
5033 {
5034   struct constructor_stack *next;
5035   tree type;
5036   tree fields;
5037   tree index;
5038   tree max_index;
5039   tree unfilled_index;
5040   tree unfilled_fields;
5041   tree bit_index;
5042   VEC(constructor_elt,gc) *elements;
5043   struct init_node *pending_elts;
5044   int offset;
5045   int depth;
5046   /* If value nonzero, this value should replace the entire
5047      constructor at this level.  */
5048   struct c_expr replacement_value;
5049   struct constructor_range_stack *range_stack;
5050   char constant;
5051   char simple;
5052   char implicit;
5053   char erroneous;
5054   char outer;
5055   char incremental;
5056   char designated;
5057 };
5058
5059 static struct constructor_stack *constructor_stack;
5060
5061 /* This stack represents designators from some range designator up to
5062    the last designator in the list.  */
5063
5064 struct constructor_range_stack
5065 {
5066   struct constructor_range_stack *next, *prev;
5067   struct constructor_stack *stack;
5068   tree range_start;
5069   tree index;
5070   tree range_end;
5071   tree fields;
5072 };
5073
5074 static struct constructor_range_stack *constructor_range_stack;
5075
5076 /* This stack records separate initializers that are nested.
5077    Nested initializers can't happen in ANSI C, but GNU C allows them
5078    in cases like { ... (struct foo) { ... } ... }.  */
5079
5080 struct initializer_stack
5081 {
5082   struct initializer_stack *next;
5083   tree decl;
5084   struct constructor_stack *constructor_stack;
5085   struct constructor_range_stack *constructor_range_stack;
5086   VEC(constructor_elt,gc) *elements;
5087   struct spelling *spelling;
5088   struct spelling *spelling_base;
5089   int spelling_size;
5090   char top_level;
5091   char require_constant_value;
5092   char require_constant_elements;
5093 };
5094
5095 static struct initializer_stack *initializer_stack;
5096 \f
5097 /* Prepare to parse and output the initializer for variable DECL.  */
5098
5099 void
5100 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5101 {
5102   const char *locus;
5103   struct initializer_stack *p = XNEW (struct initializer_stack);
5104
5105   p->decl = constructor_decl;
5106   p->require_constant_value = require_constant_value;
5107   p->require_constant_elements = require_constant_elements;
5108   p->constructor_stack = constructor_stack;
5109   p->constructor_range_stack = constructor_range_stack;
5110   p->elements = constructor_elements;
5111   p->spelling = spelling;
5112   p->spelling_base = spelling_base;
5113   p->spelling_size = spelling_size;
5114   p->top_level = constructor_top_level;
5115   p->next = initializer_stack;
5116   initializer_stack = p;
5117
5118   constructor_decl = decl;
5119   constructor_designated = 0;
5120   constructor_top_level = top_level;
5121
5122   if (decl != 0 && decl != error_mark_node)
5123     {
5124       require_constant_value = TREE_STATIC (decl);
5125       require_constant_elements
5126         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5127            /* For a scalar, you can always use any value to initialize,
5128               even within braces.  */
5129            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5130                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5131                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5132                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5133       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5134     }
5135   else
5136     {
5137       require_constant_value = 0;
5138       require_constant_elements = 0;
5139       locus = "(anonymous)";
5140     }
5141
5142   constructor_stack = 0;
5143   constructor_range_stack = 0;
5144
5145   missing_braces_mentioned = 0;
5146
5147   spelling_base = 0;
5148   spelling_size = 0;
5149   RESTORE_SPELLING_DEPTH (0);
5150
5151   if (locus)
5152     push_string (locus);
5153 }
5154
5155 void
5156 finish_init (void)
5157 {
5158   struct initializer_stack *p = initializer_stack;
5159
5160   /* Free the whole constructor stack of this initializer.  */
5161   while (constructor_stack)
5162     {
5163       struct constructor_stack *q = constructor_stack;
5164       constructor_stack = q->next;
5165       free (q);
5166     }
5167
5168   gcc_assert (!constructor_range_stack);
5169
5170   /* Pop back to the data of the outer initializer (if any).  */
5171   free (spelling_base);
5172
5173   constructor_decl = p->decl;
5174   require_constant_value = p->require_constant_value;
5175   require_constant_elements = p->require_constant_elements;
5176   constructor_stack = p->constructor_stack;
5177   constructor_range_stack = p->constructor_range_stack;
5178   constructor_elements = p->elements;
5179   spelling = p->spelling;
5180   spelling_base = p->spelling_base;
5181   spelling_size = p->spelling_size;
5182   constructor_top_level = p->top_level;
5183   initializer_stack = p->next;
5184   free (p);
5185 }
5186 \f
5187 /* Call here when we see the initializer is surrounded by braces.
5188    This is instead of a call to push_init_level;
5189    it is matched by a call to pop_init_level.
5190
5191    TYPE is the type to initialize, for a constructor expression.
5192    For an initializer for a decl, TYPE is zero.  */
5193
5194 void
5195 really_start_incremental_init (tree type)
5196 {
5197   struct constructor_stack *p = XNEW (struct constructor_stack);
5198
5199   if (type == 0)
5200     type = TREE_TYPE (constructor_decl);
5201
5202   if (targetm.vector_opaque_p (type))
5203     error ("opaque vector types cannot be initialized");
5204
5205   p->type = constructor_type;
5206   p->fields = constructor_fields;
5207   p->index = constructor_index;
5208   p->max_index = constructor_max_index;
5209   p->unfilled_index = constructor_unfilled_index;
5210   p->unfilled_fields = constructor_unfilled_fields;
5211   p->bit_index = constructor_bit_index;
5212   p->elements = constructor_elements;
5213   p->constant = constructor_constant;
5214   p->simple = constructor_simple;
5215   p->erroneous = constructor_erroneous;
5216   p->pending_elts = constructor_pending_elts;
5217   p->depth = constructor_depth;
5218   p->replacement_value.value = 0;
5219   p->replacement_value.original_code = ERROR_MARK;
5220   p->implicit = 0;
5221   p->range_stack = 0;
5222   p->outer = 0;
5223   p->incremental = constructor_incremental;
5224   p->designated = constructor_designated;
5225   p->next = 0;
5226   constructor_stack = p;
5227
5228   constructor_constant = 1;
5229   constructor_simple = 1;
5230   constructor_depth = SPELLING_DEPTH ();
5231   constructor_elements = 0;
5232   constructor_pending_elts = 0;
5233   constructor_type = type;
5234   constructor_incremental = 1;
5235   constructor_designated = 0;
5236   designator_depth = 0;
5237   designator_erroneous = 0;
5238
5239   if (TREE_CODE (constructor_type) == RECORD_TYPE
5240       || TREE_CODE (constructor_type) == UNION_TYPE)
5241     {
5242       constructor_fields = TYPE_FIELDS (constructor_type);
5243       /* Skip any nameless bit fields at the beginning.  */
5244       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5245              && DECL_NAME (constructor_fields) == 0)
5246         constructor_fields = TREE_CHAIN (constructor_fields);
5247
5248       constructor_unfilled_fields = constructor_fields;
5249       constructor_bit_index = bitsize_zero_node;
5250     }
5251   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5252     {
5253       if (TYPE_DOMAIN (constructor_type))
5254         {
5255           constructor_max_index
5256             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5257
5258           /* Detect non-empty initializations of zero-length arrays.  */
5259           if (constructor_max_index == NULL_TREE
5260               && TYPE_SIZE (constructor_type))
5261             constructor_max_index = build_int_cst (NULL_TREE, -1);
5262
5263           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5264              to initialize VLAs will cause a proper error; avoid tree
5265              checking errors as well by setting a safe value.  */
5266           if (constructor_max_index
5267               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5268             constructor_max_index = build_int_cst (NULL_TREE, -1);
5269
5270           constructor_index
5271             = convert (bitsizetype,
5272                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5273         }
5274       else
5275         {
5276           constructor_index = bitsize_zero_node;
5277           constructor_max_index = NULL_TREE;
5278         }
5279
5280       constructor_unfilled_index = constructor_index;
5281     }
5282   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5283     {
5284       /* Vectors are like simple fixed-size arrays.  */
5285       constructor_max_index =
5286         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5287       constructor_index = bitsize_zero_node;
5288       constructor_unfilled_index = constructor_index;
5289     }
5290   else
5291     {
5292       /* Handle the case of int x = {5}; */
5293       constructor_fields = constructor_type;
5294       constructor_unfilled_fields = constructor_type;
5295     }
5296 }
5297 \f
5298 /* Push down into a subobject, for initialization.
5299    If this is for an explicit set of braces, IMPLICIT is 0.
5300    If it is because the next element belongs at a lower level,
5301    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5302
5303 void
5304 push_init_level (int implicit)
5305 {
5306   struct constructor_stack *p;
5307   tree value = NULL_TREE;
5308
5309   /* If we've exhausted any levels that didn't have braces,
5310      pop them now.  If implicit == 1, this will have been done in
5311      process_init_element; do not repeat it here because in the case
5312      of excess initializers for an empty aggregate this leads to an
5313      infinite cycle of popping a level and immediately recreating
5314      it.  */
5315   if (implicit != 1)
5316     {
5317       while (constructor_stack->implicit)
5318         {
5319           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5320                || TREE_CODE (constructor_type) == UNION_TYPE)
5321               && constructor_fields == 0)
5322             process_init_element (pop_init_level (1));
5323           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5324                    && constructor_max_index
5325                    && tree_int_cst_lt (constructor_max_index,
5326                                        constructor_index))
5327             process_init_element (pop_init_level (1));
5328           else
5329             break;
5330         }
5331     }
5332
5333   /* Unless this is an explicit brace, we need to preserve previous
5334      content if any.  */
5335   if (implicit)
5336     {
5337       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5338            || TREE_CODE (constructor_type) == UNION_TYPE)
5339           && constructor_fields)
5340         value = find_init_member (constructor_fields);
5341       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5342         value = find_init_member (constructor_index);
5343     }
5344
5345   p = XNEW (struct constructor_stack);
5346   p->type = constructor_type;
5347   p->fields = constructor_fields;
5348   p->index = constructor_index;
5349   p->max_index = constructor_max_index;
5350   p->unfilled_index = constructor_unfilled_index;
5351   p->unfilled_fields = constructor_unfilled_fields;
5352   p->bit_index = constructor_bit_index;
5353   p->elements = constructor_elements;
5354   p->constant = constructor_constant;
5355   p->simple = constructor_simple;
5356   p->erroneous = constructor_erroneous;
5357   p->pending_elts = constructor_pending_elts;
5358   p->depth = constructor_depth;
5359   p->replacement_value.value = 0;
5360   p->replacement_value.original_code = ERROR_MARK;
5361   p->implicit = implicit;
5362   p->outer = 0;
5363   p->incremental = constructor_incremental;
5364   p->designated = constructor_designated;
5365   p->next = constructor_stack;
5366   p->range_stack = 0;
5367   constructor_stack = p;
5368
5369   constructor_constant = 1;
5370   constructor_simple = 1;
5371   constructor_depth = SPELLING_DEPTH ();
5372   constructor_elements = 0;
5373   constructor_incremental = 1;
5374   constructor_designated = 0;
5375   constructor_pending_elts = 0;
5376   if (!implicit)
5377     {
5378       p->range_stack = constructor_range_stack;
5379       constructor_range_stack = 0;
5380       designator_depth = 0;
5381       designator_erroneous = 0;
5382     }
5383
5384   /* Don't die if an entire brace-pair level is superfluous
5385      in the containing level.  */
5386   if (constructor_type == 0)
5387     ;
5388   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5389            || TREE_CODE (constructor_type) == UNION_TYPE)
5390     {
5391       /* Don't die if there are extra init elts at the end.  */
5392       if (constructor_fields == 0)
5393         constructor_type = 0;
5394       else
5395         {
5396           constructor_type = TREE_TYPE (constructor_fields);
5397           push_member_name (constructor_fields);
5398           constructor_depth++;
5399         }
5400     }
5401   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5402     {
5403       constructor_type = TREE_TYPE (constructor_type);
5404       push_array_bounds (tree_low_cst (constructor_index, 1));
5405       constructor_depth++;
5406     }
5407
5408   if (constructor_type == 0)
5409     {
5410       error_init ("extra brace group at end of initializer");
5411       constructor_fields = 0;
5412       constructor_unfilled_fields = 0;
5413       return;
5414     }
5415
5416   if (value && TREE_CODE (value) == CONSTRUCTOR)
5417     {
5418       constructor_constant = TREE_CONSTANT (value);
5419       constructor_simple = TREE_STATIC (value);
5420       constructor_elements = CONSTRUCTOR_ELTS (value);
5421       if (!VEC_empty (constructor_elt, constructor_elements)
5422           && (TREE_CODE (constructor_type) == RECORD_TYPE
5423               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5424         set_nonincremental_init ();
5425     }
5426
5427   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5428     {
5429       missing_braces_mentioned = 1;
5430       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5431     }
5432
5433   if (TREE_CODE (constructor_type) == RECORD_TYPE
5434            || TREE_CODE (constructor_type) == UNION_TYPE)
5435     {
5436       constructor_fields = TYPE_FIELDS (constructor_type);
5437       /* Skip any nameless bit fields at the beginning.  */
5438       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5439              && DECL_NAME (constructor_fields) == 0)
5440         constructor_fields = TREE_CHAIN (constructor_fields);
5441
5442       constructor_unfilled_fields = constructor_fields;
5443       constructor_bit_index = bitsize_zero_node;
5444     }
5445   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5446     {
5447       /* Vectors are like simple fixed-size arrays.  */
5448       constructor_max_index =
5449         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5450       constructor_index = convert (bitsizetype, integer_zero_node);
5451       constructor_unfilled_index = constructor_index;
5452     }
5453   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5454     {
5455       if (TYPE_DOMAIN (constructor_type))
5456         {
5457           constructor_max_index
5458             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5459
5460           /* Detect non-empty initializations of zero-length arrays.  */
5461           if (constructor_max_index == NULL_TREE
5462               && TYPE_SIZE (constructor_type))
5463             constructor_max_index = build_int_cst (NULL_TREE, -1);
5464
5465           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5466              to initialize VLAs will cause a proper error; avoid tree
5467              checking errors as well by setting a safe value.  */
5468           if (constructor_max_index
5469               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5470             constructor_max_index = build_int_cst (NULL_TREE, -1);
5471
5472           constructor_index
5473             = convert (bitsizetype,
5474                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5475         }
5476       else
5477         constructor_index = bitsize_zero_node;
5478
5479       constructor_unfilled_index = constructor_index;
5480       if (value && TREE_CODE (value) == STRING_CST)
5481         {
5482           /* We need to split the char/wchar array into individual
5483              characters, so that we don't have to special case it
5484              everywhere.  */
5485           set_nonincremental_init_from_string (value);
5486         }
5487     }
5488   else
5489     {
5490       if (constructor_type != error_mark_node)
5491         warning_init (0, "braces around scalar initializer");
5492       constructor_fields = constructor_type;
5493       constructor_unfilled_fields = constructor_type;
5494     }
5495 }
5496
5497 /* At the end of an implicit or explicit brace level,
5498    finish up that level of constructor.  If a single expression
5499    with redundant braces initialized that level, return the
5500    c_expr structure for that expression.  Otherwise, the original_code
5501    element is set to ERROR_MARK.
5502    If we were outputting the elements as they are read, return 0 as the value
5503    from inner levels (process_init_element ignores that),
5504    but return error_mark_node as the value from the outermost level
5505    (that's what we want to put in DECL_INITIAL).
5506    Otherwise, return a CONSTRUCTOR expression as the value.  */
5507
5508 struct c_expr
5509 pop_init_level (int implicit)
5510 {
5511   struct constructor_stack *p;
5512   struct c_expr ret;
5513   ret.value = 0;
5514   ret.original_code = ERROR_MARK;
5515
5516   if (implicit == 0)
5517     {
5518       /* When we come to an explicit close brace,
5519          pop any inner levels that didn't have explicit braces.  */
5520       while (constructor_stack->implicit)
5521         process_init_element (pop_init_level (1));
5522
5523       gcc_assert (!constructor_range_stack);
5524     }
5525
5526   /* Now output all pending elements.  */
5527   constructor_incremental = 1;
5528   output_pending_init_elements (1);
5529
5530   p = constructor_stack;
5531
5532   /* Error for initializing a flexible array member, or a zero-length
5533      array member in an inappropriate context.  */
5534   if (constructor_type && constructor_fields
5535       && TREE_CODE (constructor_type) == ARRAY_TYPE
5536       && TYPE_DOMAIN (constructor_type)
5537       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5538     {
5539       /* Silently discard empty initializations.  The parser will
5540          already have pedwarned for empty brackets.  */
5541       if (integer_zerop (constructor_unfilled_index))
5542         constructor_type = NULL_TREE;
5543       else
5544         {
5545           gcc_assert (!TYPE_SIZE (constructor_type));
5546
5547           if (constructor_depth > 2)
5548             error_init ("initialization of flexible array member in a nested context");
5549           else
5550             pedwarn_init (OPT_pedantic, "initialization of a flexible array member");
5551
5552           /* We have already issued an error message for the existence
5553              of a flexible array member not at the end of the structure.
5554              Discard the initializer so that we do not die later.  */
5555           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5556             constructor_type = NULL_TREE;
5557         }
5558     }
5559
5560   /* Warn when some struct elements are implicitly initialized to zero.  */
5561   if (warn_missing_field_initializers
5562       && constructor_type
5563       && TREE_CODE (constructor_type) == RECORD_TYPE
5564       && constructor_unfilled_fields)
5565     {
5566         /* Do not warn for flexible array members or zero-length arrays.  */
5567         while (constructor_unfilled_fields
5568                && (!DECL_SIZE (constructor_unfilled_fields)
5569                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5570           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5571
5572         /* Do not warn if this level of the initializer uses member
5573            designators; it is likely to be deliberate.  */
5574         if (constructor_unfilled_fields && !constructor_designated)
5575           {
5576             push_member_name (constructor_unfilled_fields);
5577             warning_init (OPT_Wmissing_field_initializers,
5578                           "missing initializer");
5579             RESTORE_SPELLING_DEPTH (constructor_depth);
5580           }
5581     }
5582
5583   /* Pad out the end of the structure.  */
5584   if (p->replacement_value.value)
5585     /* If this closes a superfluous brace pair,
5586        just pass out the element between them.  */
5587     ret = p->replacement_value;
5588   else if (constructor_type == 0)
5589     ;
5590   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5591            && TREE_CODE (constructor_type) != UNION_TYPE
5592            && TREE_CODE (constructor_type) != ARRAY_TYPE
5593            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5594     {
5595       /* A nonincremental scalar initializer--just return
5596          the element, after verifying there is just one.  */
5597       if (VEC_empty (constructor_elt,constructor_elements))
5598         {
5599           if (!constructor_erroneous)
5600             error_init ("empty scalar initializer");
5601           ret.value = error_mark_node;
5602         }
5603       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5604         {
5605           error_init ("extra elements in scalar initializer");
5606           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5607         }
5608       else
5609         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5610     }
5611   else
5612     {
5613       if (constructor_erroneous)
5614         ret.value = error_mark_node;
5615       else
5616         {
5617           ret.value = build_constructor (constructor_type,
5618                                          constructor_elements);
5619           if (constructor_constant)
5620             TREE_CONSTANT (ret.value) = 1;
5621           if (constructor_constant && constructor_simple)
5622             TREE_STATIC (ret.value) = 1;
5623         }
5624     }
5625
5626   constructor_type = p->type;
5627   constructor_fields = p->fields;
5628   constructor_index = p->index;
5629   constructor_max_index = p->max_index;
5630   constructor_unfilled_index = p->unfilled_index;
5631   constructor_unfilled_fields = p->unfilled_fields;
5632   constructor_bit_index = p->bit_index;
5633   constructor_elements = p->elements;
5634   constructor_constant = p->constant;
5635   constructor_simple = p->simple;
5636   constructor_erroneous = p->erroneous;
5637   constructor_incremental = p->incremental;
5638   constructor_designated = p->designated;
5639   constructor_pending_elts = p->pending_elts;
5640   constructor_depth = p->depth;
5641   if (!p->implicit)
5642     constructor_range_stack = p->range_stack;
5643   RESTORE_SPELLING_DEPTH (constructor_depth);
5644
5645   constructor_stack = p->next;
5646   free (p);
5647
5648   if (ret.value == 0 && constructor_stack == 0)
5649     ret.value = error_mark_node;
5650   return ret;
5651 }
5652
5653 /* Common handling for both array range and field name designators.
5654    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5655
5656 static int
5657 set_designator (int array)
5658 {
5659   tree subtype;
5660   enum tree_code subcode;
5661
5662   /* Don't die if an entire brace-pair level is superfluous
5663      in the containing level.  */
5664   if (constructor_type == 0)
5665     return 1;
5666
5667   /* If there were errors in this designator list already, bail out
5668      silently.  */
5669   if (designator_erroneous)
5670     return 1;
5671
5672   if (!designator_depth)
5673     {
5674       gcc_assert (!constructor_range_stack);
5675
5676       /* Designator list starts at the level of closest explicit
5677          braces.  */
5678       while (constructor_stack->implicit)
5679         process_init_element (pop_init_level (1));
5680       constructor_designated = 1;
5681       return 0;
5682     }
5683
5684   switch (TREE_CODE (constructor_type))
5685     {
5686     case  RECORD_TYPE:
5687     case  UNION_TYPE:
5688       subtype = TREE_TYPE (constructor_fields);
5689       if (subtype != error_mark_node)
5690         subtype = TYPE_MAIN_VARIANT (subtype);
5691       break;
5692     case ARRAY_TYPE:
5693       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5694       break;
5695     default:
5696       gcc_unreachable ();
5697     }
5698
5699   subcode = TREE_CODE (subtype);
5700   if (array && subcode != ARRAY_TYPE)
5701     {
5702       error_init ("array index in non-array initializer");
5703       return 1;
5704     }
5705   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5706     {
5707       error_init ("field name not in record or union initializer");
5708       return 1;
5709     }
5710
5711   constructor_designated = 1;
5712   push_init_level (2);
5713   return 0;
5714 }
5715
5716 /* If there are range designators in designator list, push a new designator
5717    to constructor_range_stack.  RANGE_END is end of such stack range or
5718    NULL_TREE if there is no range designator at this level.  */
5719
5720 static void
5721 push_range_stack (tree range_end)
5722 {
5723   struct constructor_range_stack *p;
5724
5725   p = GGC_NEW (struct constructor_range_stack);
5726   p->prev = constructor_range_stack;
5727   p->next = 0;
5728   p->fields = constructor_fields;
5729   p->range_start = constructor_index;
5730   p->index = constructor_index;
5731   p->stack = constructor_stack;
5732   p->range_end = range_end;
5733   if (constructor_range_stack)
5734     constructor_range_stack->next = p;
5735   constructor_range_stack = p;
5736 }
5737
5738 /* Within an array initializer, specify the next index to be initialized.
5739    FIRST is that index.  If LAST is nonzero, then initialize a range
5740    of indices, running from FIRST through LAST.  */
5741
5742 void
5743 set_init_index (tree first, tree last)
5744 {
5745   if (set_designator (1))
5746     return;
5747
5748   designator_erroneous = 1;
5749
5750   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5751       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5752     {
5753       error_init ("array index in initializer not of integer type");
5754       return;
5755     }
5756
5757   if (TREE_CODE (first) != INTEGER_CST)
5758     error_init ("nonconstant array index in initializer");
5759   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5760     error_init ("nonconstant array index in initializer");
5761   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5762     error_init ("array index in non-array initializer");
5763   else if (tree_int_cst_sgn (first) == -1)
5764     error_init ("array index in initializer exceeds array bounds");
5765   else if (constructor_max_index
5766            && tree_int_cst_lt (constructor_max_index, first))
5767     error_init ("array index in initializer exceeds array bounds");
5768   else
5769     {
5770       constructor_index = convert (bitsizetype, first);
5771
5772       if (last)
5773         {
5774           if (tree_int_cst_equal (first, last))
5775             last = 0;
5776           else if (tree_int_cst_lt (last, first))
5777             {
5778               error_init ("empty index range in initializer");
5779               last = 0;
5780             }
5781           else
5782             {
5783               last = convert (bitsizetype, last);
5784               if (constructor_max_index != 0
5785                   && tree_int_cst_lt (constructor_max_index, last))
5786                 {
5787                   error_init ("array index range in initializer exceeds array bounds");
5788                   last = 0;
5789                 }
5790             }
5791         }
5792
5793       designator_depth++;
5794       designator_erroneous = 0;
5795       if (constructor_range_stack || last)
5796         push_range_stack (last);
5797     }
5798 }
5799
5800 /* Within a struct initializer, specify the next field to be initialized.  */
5801
5802 void
5803 set_init_label (tree fieldname)
5804 {
5805   tree tail;
5806
5807   if (set_designator (0))
5808     return;
5809
5810   designator_erroneous = 1;
5811
5812   if (TREE_CODE (constructor_type) != RECORD_TYPE
5813       && TREE_CODE (constructor_type) != UNION_TYPE)
5814     {
5815       error_init ("field name not in record or union initializer");
5816       return;
5817     }
5818
5819   for (tail = TYPE_FIELDS (constructor_type); tail;
5820        tail = TREE_CHAIN (tail))
5821     {
5822       if (DECL_NAME (tail) == fieldname)
5823         break;
5824     }
5825
5826   if (tail == 0)
5827     error ("unknown field %qE specified in initializer", fieldname);
5828   else
5829     {
5830       constructor_fields = tail;
5831       designator_depth++;
5832       designator_erroneous = 0;
5833       if (constructor_range_stack)
5834         push_range_stack (NULL_TREE);
5835     }
5836 }
5837 \f
5838 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5839    identifies the initializer, either array index or field in a structure.
5840    VALUE is the value of that index or field.  */
5841
5842 static void
5843 add_pending_init (tree purpose, tree value)
5844 {
5845   struct init_node *p, **q, *r;
5846
5847   q = &constructor_pending_elts;
5848   p = 0;
5849
5850   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5851     {
5852       while (*q != 0)
5853         {
5854           p = *q;
5855           if (tree_int_cst_lt (purpose, p->purpose))
5856             q = &p->left;
5857           else if (tree_int_cst_lt (p->purpose, purpose))
5858             q = &p->right;
5859           else
5860             {
5861               if (TREE_SIDE_EFFECTS (p->value))
5862                 warning_init (0, "initialized field with side-effects overwritten");
5863               else if (warn_override_init)
5864                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5865               p->value = value;
5866               return;
5867             }
5868         }
5869     }
5870   else
5871     {
5872       tree bitpos;
5873
5874       bitpos = bit_position (purpose);
5875       while (*q != NULL)
5876         {
5877           p = *q;
5878           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5879             q = &p->left;
5880           else if (p->purpose != purpose)
5881             q = &p->right;
5882           else
5883             {
5884               if (TREE_SIDE_EFFECTS (p->value))
5885                 warning_init (0, "initialized field with side-effects overwritten");
5886               else if (warn_override_init)
5887                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5888               p->value = value;
5889               return;
5890             }
5891         }
5892     }
5893
5894   r = GGC_NEW (struct init_node);
5895   r->purpose = purpose;
5896   r->value = value;
5897
5898   *q = r;
5899   r->parent = p;
5900   r->left = 0;
5901   r->right = 0;
5902   r->balance = 0;
5903
5904   while (p)
5905     {
5906       struct init_node *s;
5907
5908       if (r == p->left)
5909         {
5910           if (p->balance == 0)
5911             p->balance = -1;
5912           else if (p->balance < 0)
5913             {
5914               if (r->balance < 0)
5915                 {
5916                   /* L rotation.  */
5917                   p->left = r->right;
5918                   if (p->left)
5919                     p->left->parent = p;
5920                   r->right = p;
5921
5922                   p->balance = 0;
5923                   r->balance = 0;
5924
5925                   s = p->parent;
5926                   p->parent = r;
5927                   r->parent = s;
5928                   if (s)
5929                     {
5930                       if (s->left == p)
5931                         s->left = r;
5932                       else
5933                         s->right = r;
5934                     }
5935                   else
5936                     constructor_pending_elts = r;
5937                 }
5938               else
5939                 {
5940                   /* LR rotation.  */
5941                   struct init_node *t = r->right;
5942
5943                   r->right = t->left;
5944                   if (r->right)
5945                     r->right->parent = r;
5946                   t->left = r;
5947
5948                   p->left = t->right;
5949                   if (p->left)
5950                     p->left->parent = p;
5951                   t->right = p;
5952
5953                   p->balance = t->balance < 0;
5954                   r->balance = -(t->balance > 0);
5955                   t->balance = 0;
5956
5957                   s = p->parent;
5958                   p->parent = t;
5959                   r->parent = t;
5960                   t->parent = s;
5961                   if (s)
5962                     {
5963                       if (s->left == p)
5964                         s->left = t;
5965                       else
5966                         s->right = t;
5967                     }
5968                   else
5969                     constructor_pending_elts = t;
5970                 }
5971               break;
5972             }
5973           else
5974             {
5975               /* p->balance == +1; growth of left side balances the node.  */
5976               p->balance = 0;
5977               break;
5978             }
5979         }
5980       else /* r == p->right */
5981         {
5982           if (p->balance == 0)
5983             /* Growth propagation from right side.  */
5984             p->balance++;
5985           else if (p->balance > 0)
5986             {
5987               if (r->balance > 0)
5988                 {
5989                   /* R rotation.  */
5990                   p->right = r->left;
5991                   if (p->right)
5992                     p->right->parent = p;
5993                   r->left = p;
5994
5995                   p->balance = 0;
5996                   r->balance = 0;
5997
5998                   s = p->parent;
5999                   p->parent = r;
6000                   r->parent = s;
6001                   if (s)
6002                     {
6003                       if (s->left == p)
6004                         s->left = r;
6005                       else
6006                         s->right = r;
6007                     }
6008                   else
6009                     constructor_pending_elts = r;
6010                 }
6011               else /* r->balance == -1 */
6012                 {
6013                   /* RL rotation */
6014                   struct init_node *t = r->left;
6015
6016                   r->left = t->right;
6017                   if (r->left)
6018                     r->left->parent = r;
6019                   t->right = r;
6020
6021                   p->right = t->left;
6022                   if (p->right)
6023                     p->right->parent = p;
6024                   t->left = p;
6025
6026                   r->balance = (t->balance < 0);
6027                   p->balance = -(t->balance > 0);
6028                   t->balance = 0;
6029
6030                   s = p->parent;
6031                   p->parent = t;
6032                   r->parent = t;
6033                   t->parent = s;
6034                   if (s)
6035                     {
6036                       if (s->left == p)
6037                         s->left = t;
6038                       else
6039                         s->right = t;
6040                     }
6041                   else
6042                     constructor_pending_elts = t;
6043                 }
6044               break;
6045             }
6046           else
6047             {
6048               /* p->balance == -1; growth of right side balances the node.  */
6049               p->balance = 0;
6050               break;
6051             }
6052         }
6053
6054       r = p;
6055       p = p->parent;
6056     }
6057 }
6058
6059 /* Build AVL tree from a sorted chain.  */
6060
6061 static void
6062 set_nonincremental_init (void)
6063 {
6064   unsigned HOST_WIDE_INT ix;
6065   tree index, value;
6066
6067   if (TREE_CODE (constructor_type) != RECORD_TYPE
6068       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6069     return;
6070
6071   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6072     add_pending_init (index, value);
6073   constructor_elements = 0;
6074   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6075     {
6076       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6077       /* Skip any nameless bit fields at the beginning.  */
6078       while (constructor_unfilled_fields != 0
6079              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6080              && DECL_NAME (constructor_unfilled_fields) == 0)
6081         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6082
6083     }
6084   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6085     {
6086       if (TYPE_DOMAIN (constructor_type))
6087         constructor_unfilled_index
6088             = convert (bitsizetype,
6089                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6090       else
6091         constructor_unfilled_index = bitsize_zero_node;
6092     }
6093   constructor_incremental = 0;
6094 }
6095
6096 /* Build AVL tree from a string constant.  */
6097
6098 static void
6099 set_nonincremental_init_from_string (tree str)
6100 {
6101   tree value, purpose, type;
6102   HOST_WIDE_INT val[2];
6103   const char *p, *end;
6104   int byte, wchar_bytes, charwidth, bitpos;
6105
6106   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6107
6108   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6109   charwidth = TYPE_PRECISION (char_type_node);
6110   type = TREE_TYPE (constructor_type);
6111   p = TREE_STRING_POINTER (str);
6112   end = p + TREE_STRING_LENGTH (str);
6113
6114   for (purpose = bitsize_zero_node;
6115        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6116        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6117     {
6118       if (wchar_bytes == 1)
6119         {
6120           val[1] = (unsigned char) *p++;
6121           val[0] = 0;
6122         }
6123       else
6124         {
6125           val[0] = 0;
6126           val[1] = 0;
6127           for (byte = 0; byte < wchar_bytes; byte++)
6128             {
6129               if (BYTES_BIG_ENDIAN)
6130                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6131               else
6132                 bitpos = byte * charwidth;
6133               val[bitpos < HOST_BITS_PER_WIDE_INT]
6134                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6135                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6136             }
6137         }
6138
6139       if (!TYPE_UNSIGNED (type))
6140         {
6141           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6142           if (bitpos < HOST_BITS_PER_WIDE_INT)
6143             {
6144               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6145                 {
6146                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6147                   val[0] = -1;
6148                 }
6149             }
6150           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6151             {
6152               if (val[1] < 0)
6153                 val[0] = -1;
6154             }
6155           else if (val[0] & (((HOST_WIDE_INT) 1)
6156                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6157             val[0] |= ((HOST_WIDE_INT) -1)
6158                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6159         }
6160
6161       value = build_int_cst_wide (type, val[1], val[0]);
6162       add_pending_init (purpose, value);
6163     }
6164
6165   constructor_incremental = 0;
6166 }
6167
6168 /* Return value of FIELD in pending initializer or zero if the field was
6169    not initialized yet.  */
6170
6171 static tree
6172 find_init_member (tree field)
6173 {
6174   struct init_node *p;
6175
6176   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6177     {
6178       if (constructor_incremental
6179           && tree_int_cst_lt (field, constructor_unfilled_index))
6180         set_nonincremental_init ();
6181
6182       p = constructor_pending_elts;
6183       while (p)
6184         {
6185           if (tree_int_cst_lt (field, p->purpose))
6186             p = p->left;
6187           else if (tree_int_cst_lt (p->purpose, field))
6188             p = p->right;
6189           else
6190             return p->value;
6191         }
6192     }
6193   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6194     {
6195       tree bitpos = bit_position (field);
6196
6197       if (constructor_incremental
6198           && (!constructor_unfilled_fields
6199               || tree_int_cst_lt (bitpos,
6200                                   bit_position (constructor_unfilled_fields))))
6201         set_nonincremental_init ();
6202
6203       p = constructor_pending_elts;
6204       while (p)
6205         {
6206           if (field == p->purpose)
6207             return p->value;
6208           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6209             p = p->left;
6210           else
6211             p = p->right;
6212         }
6213     }
6214   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6215     {
6216       if (!VEC_empty (constructor_elt, constructor_elements)
6217           && (VEC_last (constructor_elt, constructor_elements)->index
6218               == field))
6219         return VEC_last (constructor_elt, constructor_elements)->value;
6220     }
6221   return 0;
6222 }
6223
6224 /* "Output" the next constructor element.
6225    At top level, really output it to assembler code now.
6226    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6227    TYPE is the data type that the containing data type wants here.
6228    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6229    If VALUE is a string constant, STRICT_STRING is true if it is
6230    unparenthesized or we should not warn here for it being parenthesized.
6231    For other types of VALUE, STRICT_STRING is not used.
6232
6233    PENDING if non-nil means output pending elements that belong
6234    right after this element.  (PENDING is normally 1;
6235    it is 0 while outputting pending elements, to avoid recursion.)  */
6236
6237 static void
6238 output_init_element (tree value, bool strict_string, tree type, tree field,
6239                      int pending)
6240 {
6241   constructor_elt *celt;
6242
6243   if (type == error_mark_node || value == error_mark_node)
6244     {
6245       constructor_erroneous = 1;
6246       return;
6247     }
6248   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6249       && (TREE_CODE (value) == STRING_CST
6250           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6251       && !(TREE_CODE (value) == STRING_CST
6252            && TREE_CODE (type) == ARRAY_TYPE
6253            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6254       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6255                      TYPE_MAIN_VARIANT (type)))
6256     value = array_to_pointer_conversion (value);
6257
6258   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6259       && require_constant_value && !flag_isoc99 && pending)
6260     {
6261       /* As an extension, allow initializing objects with static storage
6262          duration with compound literals (which are then treated just as
6263          the brace enclosed list they contain).  */
6264       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6265       value = DECL_INITIAL (decl);
6266     }
6267
6268   if (value == error_mark_node)
6269     constructor_erroneous = 1;
6270   else if (!TREE_CONSTANT (value))
6271     constructor_constant = 0;
6272   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6273            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6274                 || TREE_CODE (constructor_type) == UNION_TYPE)
6275                && DECL_C_BIT_FIELD (field)
6276                && TREE_CODE (value) != INTEGER_CST))
6277     constructor_simple = 0;
6278
6279   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6280     {
6281       if (require_constant_value)
6282         {
6283           error_init ("initializer element is not constant");
6284           value = error_mark_node;
6285         }
6286       else if (require_constant_elements)
6287         pedwarn (0, "initializer element is not computable at load time");
6288     }
6289
6290   /* If this field is empty (and not at the end of structure),
6291      don't do anything other than checking the initializer.  */
6292   if (field
6293       && (TREE_TYPE (field) == error_mark_node
6294           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6295               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6296               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6297                   || TREE_CHAIN (field)))))
6298     return;
6299
6300   value = digest_init (type, value, strict_string, require_constant_value);
6301   if (value == error_mark_node)
6302     {
6303       constructor_erroneous = 1;
6304       return;
6305     }
6306
6307   /* If this element doesn't come next in sequence,
6308      put it on constructor_pending_elts.  */
6309   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6310       && (!constructor_incremental
6311           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6312     {
6313       if (constructor_incremental
6314           && tree_int_cst_lt (field, constructor_unfilled_index))
6315         set_nonincremental_init ();
6316
6317       add_pending_init (field, value);
6318       return;
6319     }
6320   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6321            && (!constructor_incremental
6322                || field != constructor_unfilled_fields))
6323     {
6324       /* We do this for records but not for unions.  In a union,
6325          no matter which field is specified, it can be initialized
6326          right away since it starts at the beginning of the union.  */
6327       if (constructor_incremental)
6328         {
6329           if (!constructor_unfilled_fields)
6330             set_nonincremental_init ();
6331           else
6332             {
6333               tree bitpos, unfillpos;
6334
6335               bitpos = bit_position (field);
6336               unfillpos = bit_position (constructor_unfilled_fields);
6337
6338               if (tree_int_cst_lt (bitpos, unfillpos))
6339                 set_nonincremental_init ();
6340             }
6341         }
6342
6343       add_pending_init (field, value);
6344       return;
6345     }
6346   else if (TREE_CODE (constructor_type) == UNION_TYPE
6347            && !VEC_empty (constructor_elt, constructor_elements))
6348     {
6349       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6350                                        constructor_elements)->value))
6351         warning_init (0, "initialized field with side-effects overwritten");
6352       else if (warn_override_init)
6353         warning_init (OPT_Woverride_init, "initialized field overwritten");
6354
6355       /* We can have just one union field set.  */
6356       constructor_elements = 0;
6357     }
6358
6359   /* Otherwise, output this element either to
6360      constructor_elements or to the assembler file.  */
6361
6362   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6363   celt->index = field;
6364   celt->value = value;
6365
6366   /* Advance the variable that indicates sequential elements output.  */
6367   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6368     constructor_unfilled_index
6369       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6370                     bitsize_one_node);
6371   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6372     {
6373       constructor_unfilled_fields
6374         = TREE_CHAIN (constructor_unfilled_fields);
6375
6376       /* Skip any nameless bit fields.  */
6377       while (constructor_unfilled_fields != 0
6378              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6379              && DECL_NAME (constructor_unfilled_fields) == 0)
6380         constructor_unfilled_fields =
6381           TREE_CHAIN (constructor_unfilled_fields);
6382     }
6383   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6384     constructor_unfilled_fields = 0;
6385
6386   /* Now output any pending elements which have become next.  */
6387   if (pending)
6388     output_pending_init_elements (0);
6389 }
6390
6391 /* Output any pending elements which have become next.
6392    As we output elements, constructor_unfilled_{fields,index}
6393    advances, which may cause other elements to become next;
6394    if so, they too are output.
6395
6396    If ALL is 0, we return when there are
6397    no more pending elements to output now.
6398
6399    If ALL is 1, we output space as necessary so that
6400    we can output all the pending elements.  */
6401
6402 static void
6403 output_pending_init_elements (int all)
6404 {
6405   struct init_node *elt = constructor_pending_elts;
6406   tree next;
6407
6408  retry:
6409
6410   /* Look through the whole pending tree.
6411      If we find an element that should be output now,
6412      output it.  Otherwise, set NEXT to the element
6413      that comes first among those still pending.  */
6414
6415   next = 0;
6416   while (elt)
6417     {
6418       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6419         {
6420           if (tree_int_cst_equal (elt->purpose,
6421                                   constructor_unfilled_index))
6422             output_init_element (elt->value, true,
6423                                  TREE_TYPE (constructor_type),
6424                                  constructor_unfilled_index, 0);
6425           else if (tree_int_cst_lt (constructor_unfilled_index,
6426                                     elt->purpose))
6427             {
6428               /* Advance to the next smaller node.  */
6429               if (elt->left)
6430                 elt = elt->left;
6431               else
6432                 {
6433                   /* We have reached the smallest node bigger than the
6434                      current unfilled index.  Fill the space first.  */
6435                   next = elt->purpose;
6436                   break;
6437                 }
6438             }
6439           else
6440             {
6441               /* Advance to the next bigger node.  */
6442               if (elt->right)
6443                 elt = elt->right;
6444               else
6445                 {
6446                   /* We have reached the biggest node in a subtree.  Find
6447                      the parent of it, which is the next bigger node.  */
6448                   while (elt->parent && elt->parent->right == elt)
6449                     elt = elt->parent;
6450                   elt = elt->parent;
6451                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6452                                               elt->purpose))
6453                     {
6454                       next = elt->purpose;
6455                       break;
6456                     }
6457                 }
6458             }
6459         }
6460       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6461                || TREE_CODE (constructor_type) == UNION_TYPE)
6462         {
6463           tree ctor_unfilled_bitpos, elt_bitpos;
6464
6465           /* If the current record is complete we are done.  */
6466           if (constructor_unfilled_fields == 0)
6467             break;
6468
6469           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6470           elt_bitpos = bit_position (elt->purpose);
6471           /* We can't compare fields here because there might be empty
6472              fields in between.  */
6473           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6474             {
6475               constructor_unfilled_fields = elt->purpose;
6476               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6477                                    elt->purpose, 0);
6478             }
6479           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6480             {
6481               /* Advance to the next smaller node.  */
6482               if (elt->left)
6483                 elt = elt->left;
6484               else
6485                 {
6486                   /* We have reached the smallest node bigger than the
6487                      current unfilled field.  Fill the space first.  */
6488                   next = elt->purpose;
6489                   break;
6490                 }
6491             }
6492           else
6493             {
6494               /* Advance to the next bigger node.  */
6495               if (elt->right)
6496                 elt = elt->right;
6497               else
6498                 {
6499                   /* We have reached the biggest node in a subtree.  Find
6500                      the parent of it, which is the next bigger node.  */
6501                   while (elt->parent && elt->parent->right == elt)
6502                     elt = elt->parent;
6503                   elt = elt->parent;
6504                   if (elt
6505                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6506                                            bit_position (elt->purpose))))
6507                     {
6508                       next = elt->purpose;
6509                       break;
6510                     }
6511                 }
6512             }
6513         }
6514     }
6515
6516   /* Ordinarily return, but not if we want to output all
6517      and there are elements left.  */
6518   if (!(all && next != 0))
6519     return;
6520
6521   /* If it's not incremental, just skip over the gap, so that after
6522      jumping to retry we will output the next successive element.  */
6523   if (TREE_CODE (constructor_type) == RECORD_TYPE
6524       || TREE_CODE (constructor_type) == UNION_TYPE)
6525     constructor_unfilled_fields = next;
6526   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6527     constructor_unfilled_index = next;
6528
6529   /* ELT now points to the node in the pending tree with the next
6530      initializer to output.  */
6531   goto retry;
6532 }
6533 \f
6534 /* Add one non-braced element to the current constructor level.
6535    This adjusts the current position within the constructor's type.
6536    This may also start or terminate implicit levels
6537    to handle a partly-braced initializer.
6538
6539    Once this has found the correct level for the new element,
6540    it calls output_init_element.  */
6541
6542 void
6543 process_init_element (struct c_expr value)
6544 {
6545   tree orig_value = value.value;
6546   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6547   bool strict_string = value.original_code == STRING_CST;
6548
6549   designator_depth = 0;
6550   designator_erroneous = 0;
6551
6552   /* Handle superfluous braces around string cst as in
6553      char x[] = {"foo"}; */
6554   if (string_flag
6555       && constructor_type
6556       && TREE_CODE (constructor_type) == ARRAY_TYPE
6557       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6558       && integer_zerop (constructor_unfilled_index))
6559     {
6560       if (constructor_stack->replacement_value.value)
6561         error_init ("excess elements in char array initializer");
6562       constructor_stack->replacement_value = value;
6563       return;
6564     }
6565
6566   if (constructor_stack->replacement_value.value != 0)
6567     {
6568       error_init ("excess elements in struct initializer");
6569       return;
6570     }
6571
6572   /* Ignore elements of a brace group if it is entirely superfluous
6573      and has already been diagnosed.  */
6574   if (constructor_type == 0)
6575     return;
6576
6577   /* If we've exhausted any levels that didn't have braces,
6578      pop them now.  */
6579   while (constructor_stack->implicit)
6580     {
6581       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6582            || TREE_CODE (constructor_type) == UNION_TYPE)
6583           && constructor_fields == 0)
6584         process_init_element (pop_init_level (1));
6585       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6586                && (constructor_max_index == 0
6587                    || tree_int_cst_lt (constructor_max_index,
6588                                        constructor_index)))
6589         process_init_element (pop_init_level (1));
6590       else
6591         break;
6592     }
6593
6594   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6595   if (constructor_range_stack)
6596     {
6597       /* If value is a compound literal and we'll be just using its
6598          content, don't put it into a SAVE_EXPR.  */
6599       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6600           || !require_constant_value
6601           || flag_isoc99)
6602         value.value = save_expr (value.value);
6603     }
6604
6605   while (1)
6606     {
6607       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6608         {
6609           tree fieldtype;
6610           enum tree_code fieldcode;
6611
6612           if (constructor_fields == 0)
6613             {
6614               pedwarn_init (0, "excess elements in struct initializer");
6615               break;
6616             }
6617
6618           fieldtype = TREE_TYPE (constructor_fields);
6619           if (fieldtype != error_mark_node)
6620             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6621           fieldcode = TREE_CODE (fieldtype);
6622
6623           /* Error for non-static initialization of a flexible array member.  */
6624           if (fieldcode == ARRAY_TYPE
6625               && !require_constant_value
6626               && TYPE_SIZE (fieldtype) == NULL_TREE
6627               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6628             {
6629               error_init ("non-static initialization of a flexible array member");
6630               break;
6631             }
6632
6633           /* Accept a string constant to initialize a subarray.  */
6634           if (value.value != 0
6635               && fieldcode == ARRAY_TYPE
6636               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6637               && string_flag)
6638             value.value = orig_value;
6639           /* Otherwise, if we have come to a subaggregate,
6640              and we don't have an element of its type, push into it.  */
6641           else if (value.value != 0
6642                    && value.value != error_mark_node
6643                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6644                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6645                        || fieldcode == UNION_TYPE))
6646             {
6647               push_init_level (1);
6648               continue;
6649             }
6650
6651           if (value.value)
6652             {
6653               push_member_name (constructor_fields);
6654               output_init_element (value.value, strict_string,
6655                                    fieldtype, constructor_fields, 1);
6656               RESTORE_SPELLING_DEPTH (constructor_depth);
6657             }
6658           else
6659             /* Do the bookkeeping for an element that was
6660                directly output as a constructor.  */
6661             {
6662               /* For a record, keep track of end position of last field.  */
6663               if (DECL_SIZE (constructor_fields))
6664                 constructor_bit_index
6665                   = size_binop (PLUS_EXPR,
6666                                 bit_position (constructor_fields),
6667                                 DECL_SIZE (constructor_fields));
6668
6669               /* If the current field was the first one not yet written out,
6670                  it isn't now, so update.  */
6671               if (constructor_unfilled_fields == constructor_fields)
6672                 {
6673                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6674                   /* Skip any nameless bit fields.  */
6675                   while (constructor_unfilled_fields != 0
6676                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6677                          && DECL_NAME (constructor_unfilled_fields) == 0)
6678                     constructor_unfilled_fields =
6679                       TREE_CHAIN (constructor_unfilled_fields);
6680                 }
6681             }
6682
6683           constructor_fields = TREE_CHAIN (constructor_fields);
6684           /* Skip any nameless bit fields at the beginning.  */
6685           while (constructor_fields != 0
6686                  && DECL_C_BIT_FIELD (constructor_fields)
6687                  && DECL_NAME (constructor_fields) == 0)
6688             constructor_fields = TREE_CHAIN (constructor_fields);
6689         }
6690       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6691         {
6692           tree fieldtype;
6693           enum tree_code fieldcode;
6694
6695           if (constructor_fields == 0)
6696             {
6697               pedwarn_init (0, "excess elements in union initializer");
6698               break;
6699             }
6700
6701           fieldtype = TREE_TYPE (constructor_fields);
6702           if (fieldtype != error_mark_node)
6703             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6704           fieldcode = TREE_CODE (fieldtype);
6705
6706           /* Warn that traditional C rejects initialization of unions.
6707              We skip the warning if the value is zero.  This is done
6708              under the assumption that the zero initializer in user
6709              code appears conditioned on e.g. __STDC__ to avoid
6710              "missing initializer" warnings and relies on default
6711              initialization to zero in the traditional C case.
6712              We also skip the warning if the initializer is designated,
6713              again on the assumption that this must be conditional on
6714              __STDC__ anyway (and we've already complained about the
6715              member-designator already).  */
6716           if (!in_system_header && !constructor_designated
6717               && !(value.value && (integer_zerop (value.value)
6718                                    || real_zerop (value.value))))
6719             warning (OPT_Wtraditional, "traditional C rejects initialization "
6720                      "of unions");
6721
6722           /* Accept a string constant to initialize a subarray.  */
6723           if (value.value != 0
6724               && fieldcode == ARRAY_TYPE
6725               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6726               && string_flag)
6727             value.value = orig_value;
6728           /* Otherwise, if we have come to a subaggregate,
6729              and we don't have an element of its type, push into it.  */
6730           else if (value.value != 0
6731                    && value.value != error_mark_node
6732                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6733                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6734                        || fieldcode == UNION_TYPE))
6735             {
6736               push_init_level (1);
6737               continue;
6738             }
6739
6740           if (value.value)
6741             {
6742               push_member_name (constructor_fields);
6743               output_init_element (value.value, strict_string,
6744                                    fieldtype, constructor_fields, 1);
6745               RESTORE_SPELLING_DEPTH (constructor_depth);
6746             }
6747           else
6748             /* Do the bookkeeping for an element that was
6749                directly output as a constructor.  */
6750             {
6751               constructor_bit_index = DECL_SIZE (constructor_fields);
6752               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6753             }
6754
6755           constructor_fields = 0;
6756         }
6757       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6758         {
6759           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6760           enum tree_code eltcode = TREE_CODE (elttype);
6761
6762           /* Accept a string constant to initialize a subarray.  */
6763           if (value.value != 0
6764               && eltcode == ARRAY_TYPE
6765               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6766               && string_flag)
6767             value.value = orig_value;
6768           /* Otherwise, if we have come to a subaggregate,
6769              and we don't have an element of its type, push into it.  */
6770           else if (value.value != 0
6771                    && value.value != error_mark_node
6772                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6773                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6774                        || eltcode == UNION_TYPE))
6775             {
6776               push_init_level (1);
6777               continue;
6778             }
6779
6780           if (constructor_max_index != 0
6781               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6782                   || integer_all_onesp (constructor_max_index)))
6783             {
6784               pedwarn_init (0, "excess elements in array initializer");
6785               break;
6786             }
6787
6788           /* Now output the actual element.  */
6789           if (value.value)
6790             {
6791               push_array_bounds (tree_low_cst (constructor_index, 1));
6792               output_init_element (value.value, strict_string,
6793                                    elttype, constructor_index, 1);
6794               RESTORE_SPELLING_DEPTH (constructor_depth);
6795             }
6796
6797           constructor_index
6798             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6799
6800           if (!value.value)
6801             /* If we are doing the bookkeeping for an element that was
6802                directly output as a constructor, we must update
6803                constructor_unfilled_index.  */
6804             constructor_unfilled_index = constructor_index;
6805         }
6806       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6807         {
6808           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6809
6810          /* Do a basic check of initializer size.  Note that vectors
6811             always have a fixed size derived from their type.  */
6812           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6813             {
6814               pedwarn_init (0, "excess elements in vector initializer");
6815               break;
6816             }
6817
6818           /* Now output the actual element.  */
6819           if (value.value)
6820             output_init_element (value.value, strict_string,
6821                                  elttype, constructor_index, 1);
6822
6823           constructor_index
6824             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6825
6826           if (!value.value)
6827             /* If we are doing the bookkeeping for an element that was
6828                directly output as a constructor, we must update
6829                constructor_unfilled_index.  */
6830             constructor_unfilled_index = constructor_index;
6831         }
6832
6833       /* Handle the sole element allowed in a braced initializer
6834          for a scalar variable.  */
6835       else if (constructor_type != error_mark_node
6836                && constructor_fields == 0)
6837         {
6838           pedwarn_init (0, "excess elements in scalar initializer");
6839           break;
6840         }
6841       else
6842         {
6843           if (value.value)
6844             output_init_element (value.value, strict_string,
6845                                  constructor_type, NULL_TREE, 1);
6846           constructor_fields = 0;
6847         }
6848
6849       /* Handle range initializers either at this level or anywhere higher
6850          in the designator stack.  */
6851       if (constructor_range_stack)
6852         {
6853           struct constructor_range_stack *p, *range_stack;
6854           int finish = 0;
6855
6856           range_stack = constructor_range_stack;
6857           constructor_range_stack = 0;
6858           while (constructor_stack != range_stack->stack)
6859             {
6860               gcc_assert (constructor_stack->implicit);
6861               process_init_element (pop_init_level (1));
6862             }
6863           for (p = range_stack;
6864                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6865                p = p->prev)
6866             {
6867               gcc_assert (constructor_stack->implicit);
6868               process_init_element (pop_init_level (1));
6869             }
6870
6871           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6872           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6873             finish = 1;
6874
6875           while (1)
6876             {
6877               constructor_index = p->index;
6878               constructor_fields = p->fields;
6879               if (finish && p->range_end && p->index == p->range_start)
6880                 {
6881                   finish = 0;
6882                   p->prev = 0;
6883                 }
6884               p = p->next;
6885               if (!p)
6886                 break;
6887               push_init_level (2);
6888               p->stack = constructor_stack;
6889               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6890                 p->index = p->range_start;
6891             }
6892
6893           if (!finish)
6894             constructor_range_stack = range_stack;
6895           continue;
6896         }
6897
6898       break;
6899     }
6900
6901   constructor_range_stack = 0;
6902 }
6903 \f
6904 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6905    (guaranteed to be 'volatile' or null) and ARGS (represented using
6906    an ASM_EXPR node).  */
6907 tree
6908 build_asm_stmt (tree cv_qualifier, tree args)
6909 {
6910   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6911     ASM_VOLATILE_P (args) = 1;
6912   return add_stmt (args);
6913 }
6914
6915 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6916    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6917    SIMPLE indicates whether there was anything at all after the
6918    string in the asm expression -- asm("blah") and asm("blah" : )
6919    are subtly different.  We use a ASM_EXPR node to represent this.  */
6920 tree
6921 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6922                 bool simple)
6923 {
6924   tree tail;
6925   tree args;
6926   int i;
6927   const char *constraint;
6928   const char **oconstraints;
6929   bool allows_mem, allows_reg, is_inout;
6930   int ninputs, noutputs;
6931
6932   ninputs = list_length (inputs);
6933   noutputs = list_length (outputs);
6934   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6935
6936   string = resolve_asm_operand_names (string, outputs, inputs);
6937
6938   /* Remove output conversions that change the type but not the mode.  */
6939   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6940     {
6941       tree output = TREE_VALUE (tail);
6942
6943       /* ??? Really, this should not be here.  Users should be using a
6944          proper lvalue, dammit.  But there's a long history of using casts
6945          in the output operands.  In cases like longlong.h, this becomes a
6946          primitive form of typechecking -- if the cast can be removed, then
6947          the output operand had a type of the proper width; otherwise we'll
6948          get an error.  Gross, but ...  */
6949       STRIP_NOPS (output);
6950
6951       if (!lvalue_or_else (output, lv_asm))
6952         output = error_mark_node;
6953
6954       if (output != error_mark_node
6955           && (TREE_READONLY (output)
6956               || TYPE_READONLY (TREE_TYPE (output))
6957               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6958                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6959                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6960         readonly_error (output, lv_asm);
6961
6962       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6963       oconstraints[i] = constraint;
6964
6965       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6966                                    &allows_mem, &allows_reg, &is_inout))
6967         {
6968           /* If the operand is going to end up in memory,
6969              mark it addressable.  */
6970           if (!allows_reg && !c_mark_addressable (output))
6971             output = error_mark_node;
6972         }
6973       else
6974         output = error_mark_node;
6975
6976       TREE_VALUE (tail) = output;
6977     }
6978
6979   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6980     {
6981       tree input;
6982
6983       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6984       input = TREE_VALUE (tail);
6985
6986       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6987                                   oconstraints, &allows_mem, &allows_reg))
6988         {
6989           /* If the operand is going to end up in memory,
6990              mark it addressable.  */
6991           if (!allows_reg && allows_mem)
6992             {
6993               /* Strip the nops as we allow this case.  FIXME, this really
6994                  should be rejected or made deprecated.  */
6995               STRIP_NOPS (input);
6996               if (!c_mark_addressable (input))
6997                 input = error_mark_node;
6998           }
6999         }
7000       else
7001         input = error_mark_node;
7002
7003       TREE_VALUE (tail) = input;
7004     }
7005
7006   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7007
7008   /* asm statements without outputs, including simple ones, are treated
7009      as volatile.  */
7010   ASM_INPUT_P (args) = simple;
7011   ASM_VOLATILE_P (args) = (noutputs == 0);
7012
7013   return args;
7014 }
7015 \f
7016 /* Generate a goto statement to LABEL.  */
7017
7018 tree
7019 c_finish_goto_label (tree label)
7020 {
7021   tree decl = lookup_label (label);
7022   if (!decl)
7023     return NULL_TREE;
7024
7025   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7026     {
7027       error ("jump into statement expression");
7028       return NULL_TREE;
7029     }
7030
7031   if (C_DECL_UNJUMPABLE_VM (decl))
7032     {
7033       error ("jump into scope of identifier with variably modified type");
7034       return NULL_TREE;
7035     }
7036
7037   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7038     {
7039       /* No jump from outside this statement expression context, so
7040          record that there is a jump from within this context.  */
7041       struct c_label_list *nlist;
7042       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7043       nlist->next = label_context_stack_se->labels_used;
7044       nlist->label = decl;
7045       label_context_stack_se->labels_used = nlist;
7046     }
7047
7048   if (!C_DECL_UNDEFINABLE_VM (decl))
7049     {
7050       /* No jump from outside this context context of identifiers with
7051          variably modified type, so record that there is a jump from
7052          within this context.  */
7053       struct c_label_list *nlist;
7054       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7055       nlist->next = label_context_stack_vm->labels_used;
7056       nlist->label = decl;
7057       label_context_stack_vm->labels_used = nlist;
7058     }
7059
7060   TREE_USED (decl) = 1;
7061   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7062 }
7063
7064 /* Generate a computed goto statement to EXPR.  */
7065
7066 tree
7067 c_finish_goto_ptr (tree expr)
7068 {
7069   pedwarn (OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7070   expr = convert (ptr_type_node, expr);
7071   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7072 }
7073
7074 /* Generate a C `return' statement.  RETVAL is the expression for what
7075    to return, or a null pointer for `return;' with no value.  */
7076
7077 tree
7078 c_finish_return (tree retval)
7079 {
7080   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7081   bool no_warning = false;
7082
7083   if (TREE_THIS_VOLATILE (current_function_decl))
7084     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7085
7086   if (!retval)
7087     {
7088       current_function_returns_null = 1;
7089       if ((warn_return_type || flag_isoc99)
7090           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7091         {
7092           pedwarn_c99 (flag_isoc99 ? 0 : OPT_Wreturn_type,
7093                        "%<return%> with no value, in "
7094                        "function returning non-void");
7095           no_warning = true;
7096         }
7097     }
7098   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7099     {
7100       current_function_returns_null = 1;
7101       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7102         pedwarn (0, "%<return%> with a value, in function returning void");
7103       else
7104         pedwarn (OPT_pedantic, "ISO C forbids "
7105                  "%<return%> with expression, in function returning void");
7106     }
7107   else
7108     {
7109       tree t = convert_for_assignment (valtype, retval, ic_return,
7110                                        NULL_TREE, NULL_TREE, 0);
7111       tree res = DECL_RESULT (current_function_decl);
7112       tree inner;
7113
7114       current_function_returns_value = 1;
7115       if (t == error_mark_node)
7116         return NULL_TREE;
7117
7118       inner = t = convert (TREE_TYPE (res), t);
7119
7120       /* Strip any conversions, additions, and subtractions, and see if
7121          we are returning the address of a local variable.  Warn if so.  */
7122       while (1)
7123         {
7124           switch (TREE_CODE (inner))
7125             {
7126             CASE_CONVERT:   case NON_LVALUE_EXPR:
7127             case PLUS_EXPR:
7128               inner = TREE_OPERAND (inner, 0);
7129               continue;
7130
7131             case MINUS_EXPR:
7132               /* If the second operand of the MINUS_EXPR has a pointer
7133                  type (or is converted from it), this may be valid, so
7134                  don't give a warning.  */
7135               {
7136                 tree op1 = TREE_OPERAND (inner, 1);
7137
7138                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7139                        && (CONVERT_EXPR_P (op1)
7140                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7141                   op1 = TREE_OPERAND (op1, 0);
7142
7143                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7144                   break;
7145
7146                 inner = TREE_OPERAND (inner, 0);
7147                 continue;
7148               }
7149
7150             case ADDR_EXPR:
7151               inner = TREE_OPERAND (inner, 0);
7152
7153               while (REFERENCE_CLASS_P (inner)
7154                      && TREE_CODE (inner) != INDIRECT_REF)
7155                 inner = TREE_OPERAND (inner, 0);
7156
7157               if (DECL_P (inner)
7158                   && !DECL_EXTERNAL (inner)
7159                   && !TREE_STATIC (inner)
7160                   && DECL_CONTEXT (inner) == current_function_decl)
7161                 warning (0, "function returns address of local variable");
7162               break;
7163
7164             default:
7165               break;
7166             }
7167
7168           break;
7169         }
7170
7171       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7172
7173       if (warn_sequence_point)
7174         verify_sequence_points (retval);
7175     }
7176
7177   ret_stmt = build_stmt (RETURN_EXPR, retval);
7178   TREE_NO_WARNING (ret_stmt) |= no_warning;
7179   return add_stmt (ret_stmt);
7180 }
7181 \f
7182 struct c_switch {
7183   /* The SWITCH_EXPR being built.  */
7184   tree switch_expr;
7185
7186   /* The original type of the testing expression, i.e. before the
7187      default conversion is applied.  */
7188   tree orig_type;
7189
7190   /* A splay-tree mapping the low element of a case range to the high
7191      element, or NULL_TREE if there is no high element.  Used to
7192      determine whether or not a new case label duplicates an old case
7193      label.  We need a tree, rather than simply a hash table, because
7194      of the GNU case range extension.  */
7195   splay_tree cases;
7196
7197   /* Number of nested statement expressions within this switch
7198      statement; if nonzero, case and default labels may not
7199      appear.  */
7200   unsigned int blocked_stmt_expr;
7201
7202   /* Scope of outermost declarations of identifiers with variably
7203      modified type within this switch statement; if nonzero, case and
7204      default labels may not appear.  */
7205   unsigned int blocked_vm;
7206
7207   /* The next node on the stack.  */
7208   struct c_switch *next;
7209 };
7210
7211 /* A stack of the currently active switch statements.  The innermost
7212    switch statement is on the top of the stack.  There is no need to
7213    mark the stack for garbage collection because it is only active
7214    during the processing of the body of a function, and we never
7215    collect at that point.  */
7216
7217 struct c_switch *c_switch_stack;
7218
7219 /* Start a C switch statement, testing expression EXP.  Return the new
7220    SWITCH_EXPR.  */
7221
7222 tree
7223 c_start_case (tree exp)
7224 {
7225   tree orig_type = error_mark_node;
7226   struct c_switch *cs;
7227
7228   if (exp != error_mark_node)
7229     {
7230       orig_type = TREE_TYPE (exp);
7231
7232       if (!INTEGRAL_TYPE_P (orig_type))
7233         {
7234           if (orig_type != error_mark_node)
7235             {
7236               error ("switch quantity not an integer");
7237               orig_type = error_mark_node;
7238             }
7239           exp = integer_zero_node;
7240         }
7241       else
7242         {
7243           tree type = TYPE_MAIN_VARIANT (orig_type);
7244
7245           if (!in_system_header
7246               && (type == long_integer_type_node
7247                   || type == long_unsigned_type_node))
7248             warning (OPT_Wtraditional, "%<long%> switch expression not "
7249                      "converted to %<int%> in ISO C");
7250
7251           exp = default_conversion (exp);
7252
7253           if (warn_sequence_point)
7254             verify_sequence_points (exp);
7255         }
7256     }
7257
7258   /* Add this new SWITCH_EXPR to the stack.  */
7259   cs = XNEW (struct c_switch);
7260   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7261   cs->orig_type = orig_type;
7262   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7263   cs->blocked_stmt_expr = 0;
7264   cs->blocked_vm = 0;
7265   cs->next = c_switch_stack;
7266   c_switch_stack = cs;
7267
7268   return add_stmt (cs->switch_expr);
7269 }
7270
7271 /* Process a case label.  */
7272
7273 tree
7274 do_case (tree low_value, tree high_value)
7275 {
7276   tree label = NULL_TREE;
7277
7278   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7279       && !c_switch_stack->blocked_vm)
7280     {
7281       label = c_add_case_label (c_switch_stack->cases,
7282                                 SWITCH_COND (c_switch_stack->switch_expr),
7283                                 c_switch_stack->orig_type,
7284                                 low_value, high_value);
7285       if (label == error_mark_node)
7286         label = NULL_TREE;
7287     }
7288   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7289     {
7290       if (low_value)
7291         error ("case label in statement expression not containing "
7292                "enclosing switch statement");
7293       else
7294         error ("%<default%> label in statement expression not containing "
7295                "enclosing switch statement");
7296     }
7297   else if (c_switch_stack && c_switch_stack->blocked_vm)
7298     {
7299       if (low_value)
7300         error ("case label in scope of identifier with variably modified "
7301                "type not containing enclosing switch statement");
7302       else
7303         error ("%<default%> label in scope of identifier with variably "
7304                "modified type not containing enclosing switch statement");
7305     }
7306   else if (low_value)
7307     error ("case label not within a switch statement");
7308   else
7309     error ("%<default%> label not within a switch statement");
7310
7311   return label;
7312 }
7313
7314 /* Finish the switch statement.  */
7315
7316 void
7317 c_finish_case (tree body)
7318 {
7319   struct c_switch *cs = c_switch_stack;
7320   location_t switch_location;
7321
7322   SWITCH_BODY (cs->switch_expr) = body;
7323
7324   /* We must not be within a statement expression nested in the switch
7325      at this point; we might, however, be within the scope of an
7326      identifier with variably modified type nested in the switch.  */
7327   gcc_assert (!cs->blocked_stmt_expr);
7328
7329   /* Emit warnings as needed.  */
7330   if (EXPR_HAS_LOCATION (cs->switch_expr))
7331     switch_location = EXPR_LOCATION (cs->switch_expr);
7332   else
7333     switch_location = input_location;
7334   c_do_switch_warnings (cs->cases, switch_location,
7335                         TREE_TYPE (cs->switch_expr),
7336                         SWITCH_COND (cs->switch_expr));
7337
7338   /* Pop the stack.  */
7339   c_switch_stack = cs->next;
7340   splay_tree_delete (cs->cases);
7341   XDELETE (cs);
7342 }
7343 \f
7344 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7345    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7346    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7347    statement, and was not surrounded with parenthesis.  */
7348
7349 void
7350 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7351                   tree else_block, bool nested_if)
7352 {
7353   tree stmt;
7354
7355   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7356   if (warn_parentheses && nested_if && else_block == NULL)
7357     {
7358       tree inner_if = then_block;
7359
7360       /* We know from the grammar productions that there is an IF nested
7361          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7362          it might not be exactly THEN_BLOCK, but should be the last
7363          non-container statement within.  */
7364       while (1)
7365         switch (TREE_CODE (inner_if))
7366           {
7367           case COND_EXPR:
7368             goto found;
7369           case BIND_EXPR:
7370             inner_if = BIND_EXPR_BODY (inner_if);
7371             break;
7372           case STATEMENT_LIST:
7373             inner_if = expr_last (then_block);
7374             break;
7375           case TRY_FINALLY_EXPR:
7376           case TRY_CATCH_EXPR:
7377             inner_if = TREE_OPERAND (inner_if, 0);
7378             break;
7379           default:
7380             gcc_unreachable ();
7381           }
7382     found:
7383
7384       if (COND_EXPR_ELSE (inner_if))
7385          warning (OPT_Wparentheses,
7386                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7387                   &if_locus);
7388     }
7389
7390   empty_if_body_warning (then_block, else_block);
7391
7392   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7393   SET_EXPR_LOCATION (stmt, if_locus);
7394   add_stmt (stmt);
7395 }
7396
7397 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7398    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7399    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7400    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7401    the continue label.  Everything is allowed to be NULL.  */
7402
7403 void
7404 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7405                tree blab, tree clab, bool cond_is_first)
7406 {
7407   tree entry = NULL, exit = NULL, t;
7408
7409   /* If the condition is zero don't generate a loop construct.  */
7410   if (cond && integer_zerop (cond))
7411     {
7412       if (cond_is_first)
7413         {
7414           t = build_and_jump (&blab);
7415           SET_EXPR_LOCATION (t, start_locus);
7416           add_stmt (t);
7417         }
7418     }
7419   else
7420     {
7421       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7422
7423       /* If we have an exit condition, then we build an IF with gotos either
7424          out of the loop, or to the top of it.  If there's no exit condition,
7425          then we just build a jump back to the top.  */
7426       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7427
7428       if (cond && !integer_nonzerop (cond))
7429         {
7430           /* Canonicalize the loop condition to the end.  This means
7431              generating a branch to the loop condition.  Reuse the
7432              continue label, if possible.  */
7433           if (cond_is_first)
7434             {
7435               if (incr || !clab)
7436                 {
7437                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7438                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7439                 }
7440               else
7441                 t = build1 (GOTO_EXPR, void_type_node, clab);
7442               SET_EXPR_LOCATION (t, start_locus);
7443               add_stmt (t);
7444             }
7445
7446           t = build_and_jump (&blab);
7447           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7448           if (cond_is_first)
7449             SET_EXPR_LOCATION (exit, start_locus);
7450           else
7451             SET_EXPR_LOCATION (exit, input_location);
7452         }
7453
7454       add_stmt (top);
7455     }
7456
7457   if (body)
7458     add_stmt (body);
7459   if (clab)
7460     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7461   if (incr)
7462     add_stmt (incr);
7463   if (entry)
7464     add_stmt (entry);
7465   if (exit)
7466     add_stmt (exit);
7467   if (blab)
7468     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7469 }
7470
7471 tree
7472 c_finish_bc_stmt (tree *label_p, bool is_break)
7473 {
7474   bool skip;
7475   tree label = *label_p;
7476
7477   /* In switch statements break is sometimes stylistically used after
7478      a return statement.  This can lead to spurious warnings about
7479      control reaching the end of a non-void function when it is
7480      inlined.  Note that we are calling block_may_fallthru with
7481      language specific tree nodes; this works because
7482      block_may_fallthru returns true when given something it does not
7483      understand.  */
7484   skip = !block_may_fallthru (cur_stmt_list);
7485
7486   if (!label)
7487     {
7488       if (!skip)
7489         *label_p = label = create_artificial_label ();
7490     }
7491   else if (TREE_CODE (label) == LABEL_DECL)
7492     ;
7493   else switch (TREE_INT_CST_LOW (label))
7494     {
7495     case 0:
7496       if (is_break)
7497         error ("break statement not within loop or switch");
7498       else
7499         error ("continue statement not within a loop");
7500       return NULL_TREE;
7501
7502     case 1:
7503       gcc_assert (is_break);
7504       error ("break statement used with OpenMP for loop");
7505       return NULL_TREE;
7506
7507     default:
7508       gcc_unreachable ();
7509     }
7510
7511   if (skip)
7512     return NULL_TREE;
7513
7514   if (!is_break)
7515     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7516
7517   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7518 }
7519
7520 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7521
7522 static void
7523 emit_side_effect_warnings (tree expr)
7524 {
7525   if (expr == error_mark_node)
7526     ;
7527   else if (!TREE_SIDE_EFFECTS (expr))
7528     {
7529       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7530         warning (OPT_Wunused_value, "%Hstatement with no effect",
7531                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7532     }
7533   else
7534     warn_if_unused_value (expr, input_location);
7535 }
7536
7537 /* Process an expression as if it were a complete statement.  Emit
7538    diagnostics, but do not call ADD_STMT.  */
7539
7540 tree
7541 c_process_expr_stmt (tree expr)
7542 {
7543   if (!expr)
7544     return NULL_TREE;
7545
7546   if (warn_sequence_point)
7547     verify_sequence_points (expr);
7548
7549   if (TREE_TYPE (expr) != error_mark_node
7550       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7551       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7552     error ("expression statement has incomplete type");
7553
7554   /* If we're not processing a statement expression, warn about unused values.
7555      Warnings for statement expressions will be emitted later, once we figure
7556      out which is the result.  */
7557   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7558       && warn_unused_value)
7559     emit_side_effect_warnings (expr);
7560
7561   /* If the expression is not of a type to which we cannot assign a line
7562      number, wrap the thing in a no-op NOP_EXPR.  */
7563   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7564     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7565
7566   if (CAN_HAVE_LOCATION_P (expr))
7567     SET_EXPR_LOCATION (expr, input_location);
7568
7569   return expr;
7570 }
7571
7572 /* Emit an expression as a statement.  */
7573
7574 tree
7575 c_finish_expr_stmt (tree expr)
7576 {
7577   if (expr)
7578     return add_stmt (c_process_expr_stmt (expr));
7579   else
7580     return NULL;
7581 }
7582
7583 /* Do the opposite and emit a statement as an expression.  To begin,
7584    create a new binding level and return it.  */
7585
7586 tree
7587 c_begin_stmt_expr (void)
7588 {
7589   tree ret;
7590   struct c_label_context_se *nstack;
7591   struct c_label_list *glist;
7592
7593   /* We must force a BLOCK for this level so that, if it is not expanded
7594      later, there is a way to turn off the entire subtree of blocks that
7595      are contained in it.  */
7596   keep_next_level ();
7597   ret = c_begin_compound_stmt (true);
7598   if (c_switch_stack)
7599     {
7600       c_switch_stack->blocked_stmt_expr++;
7601       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7602     }
7603   for (glist = label_context_stack_se->labels_used;
7604        glist != NULL;
7605        glist = glist->next)
7606     {
7607       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7608     }
7609   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7610   nstack->labels_def = NULL;
7611   nstack->labels_used = NULL;
7612   nstack->next = label_context_stack_se;
7613   label_context_stack_se = nstack;
7614
7615   /* Mark the current statement list as belonging to a statement list.  */
7616   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7617
7618   return ret;
7619 }
7620
7621 tree
7622 c_finish_stmt_expr (tree body)
7623 {
7624   tree last, type, tmp, val;
7625   tree *last_p;
7626   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7627
7628   body = c_end_compound_stmt (body, true);
7629   if (c_switch_stack)
7630     {
7631       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7632       c_switch_stack->blocked_stmt_expr--;
7633     }
7634   /* It is no longer possible to jump to labels defined within this
7635      statement expression.  */
7636   for (dlist = label_context_stack_se->labels_def;
7637        dlist != NULL;
7638        dlist = dlist->next)
7639     {
7640       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7641     }
7642   /* It is again possible to define labels with a goto just outside
7643      this statement expression.  */
7644   for (glist = label_context_stack_se->next->labels_used;
7645        glist != NULL;
7646        glist = glist->next)
7647     {
7648       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7649       glist_prev = glist;
7650     }
7651   if (glist_prev != NULL)
7652     glist_prev->next = label_context_stack_se->labels_used;
7653   else
7654     label_context_stack_se->next->labels_used
7655       = label_context_stack_se->labels_used;
7656   label_context_stack_se = label_context_stack_se->next;
7657
7658   /* Locate the last statement in BODY.  See c_end_compound_stmt
7659      about always returning a BIND_EXPR.  */
7660   last_p = &BIND_EXPR_BODY (body);
7661   last = BIND_EXPR_BODY (body);
7662
7663  continue_searching:
7664   if (TREE_CODE (last) == STATEMENT_LIST)
7665     {
7666       tree_stmt_iterator i;
7667
7668       /* This can happen with degenerate cases like ({ }).  No value.  */
7669       if (!TREE_SIDE_EFFECTS (last))
7670         return body;
7671
7672       /* If we're supposed to generate side effects warnings, process
7673          all of the statements except the last.  */
7674       if (warn_unused_value)
7675         {
7676           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7677             emit_side_effect_warnings (tsi_stmt (i));
7678         }
7679       else
7680         i = tsi_last (last);
7681       last_p = tsi_stmt_ptr (i);
7682       last = *last_p;
7683     }
7684
7685   /* If the end of the list is exception related, then the list was split
7686      by a call to push_cleanup.  Continue searching.  */
7687   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7688       || TREE_CODE (last) == TRY_CATCH_EXPR)
7689     {
7690       last_p = &TREE_OPERAND (last, 0);
7691       last = *last_p;
7692       goto continue_searching;
7693     }
7694
7695   /* In the case that the BIND_EXPR is not necessary, return the
7696      expression out from inside it.  */
7697   if (last == error_mark_node
7698       || (last == BIND_EXPR_BODY (body)
7699           && BIND_EXPR_VARS (body) == NULL))
7700     {
7701       /* Do not warn if the return value of a statement expression is
7702          unused.  */
7703       if (CAN_HAVE_LOCATION_P (last))
7704         TREE_NO_WARNING (last) = 1;
7705       return last;
7706     }
7707
7708   /* Extract the type of said expression.  */
7709   type = TREE_TYPE (last);
7710
7711   /* If we're not returning a value at all, then the BIND_EXPR that
7712      we already have is a fine expression to return.  */
7713   if (!type || VOID_TYPE_P (type))
7714     return body;
7715
7716   /* Now that we've located the expression containing the value, it seems
7717      silly to make voidify_wrapper_expr repeat the process.  Create a
7718      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7719   tmp = create_tmp_var_raw (type, NULL);
7720
7721   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7722      tree_expr_nonnegative_p giving up immediately.  */
7723   val = last;
7724   if (TREE_CODE (val) == NOP_EXPR
7725       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7726     val = TREE_OPERAND (val, 0);
7727
7728   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7729   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7730
7731   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7732 }
7733
7734 /* Begin the scope of an identifier of variably modified type, scope
7735    number SCOPE.  Jumping from outside this scope to inside it is not
7736    permitted.  */
7737
7738 void
7739 c_begin_vm_scope (unsigned int scope)
7740 {
7741   struct c_label_context_vm *nstack;
7742   struct c_label_list *glist;
7743
7744   gcc_assert (scope > 0);
7745
7746   /* At file_scope, we don't have to do any processing.  */
7747   if (label_context_stack_vm == NULL)
7748     return;
7749
7750   if (c_switch_stack && !c_switch_stack->blocked_vm)
7751     c_switch_stack->blocked_vm = scope;
7752   for (glist = label_context_stack_vm->labels_used;
7753        glist != NULL;
7754        glist = glist->next)
7755     {
7756       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7757     }
7758   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7759   nstack->labels_def = NULL;
7760   nstack->labels_used = NULL;
7761   nstack->scope = scope;
7762   nstack->next = label_context_stack_vm;
7763   label_context_stack_vm = nstack;
7764 }
7765
7766 /* End a scope which may contain identifiers of variably modified
7767    type, scope number SCOPE.  */
7768
7769 void
7770 c_end_vm_scope (unsigned int scope)
7771 {
7772   if (label_context_stack_vm == NULL)
7773     return;
7774   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7775     c_switch_stack->blocked_vm = 0;
7776   /* We may have a number of nested scopes of identifiers with
7777      variably modified type, all at this depth.  Pop each in turn.  */
7778   while (label_context_stack_vm->scope == scope)
7779     {
7780       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7781
7782       /* It is no longer possible to jump to labels defined within this
7783          scope.  */
7784       for (dlist = label_context_stack_vm->labels_def;
7785            dlist != NULL;
7786            dlist = dlist->next)
7787         {
7788           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7789         }
7790       /* It is again possible to define labels with a goto just outside
7791          this scope.  */
7792       for (glist = label_context_stack_vm->next->labels_used;
7793            glist != NULL;
7794            glist = glist->next)
7795         {
7796           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7797           glist_prev = glist;
7798         }
7799       if (glist_prev != NULL)
7800         glist_prev->next = label_context_stack_vm->labels_used;
7801       else
7802         label_context_stack_vm->next->labels_used
7803           = label_context_stack_vm->labels_used;
7804       label_context_stack_vm = label_context_stack_vm->next;
7805     }
7806 }
7807 \f
7808 /* Begin and end compound statements.  This is as simple as pushing
7809    and popping new statement lists from the tree.  */
7810
7811 tree
7812 c_begin_compound_stmt (bool do_scope)
7813 {
7814   tree stmt = push_stmt_list ();
7815   if (do_scope)
7816     push_scope ();
7817   return stmt;
7818 }
7819
7820 tree
7821 c_end_compound_stmt (tree stmt, bool do_scope)
7822 {
7823   tree block = NULL;
7824
7825   if (do_scope)
7826     {
7827       if (c_dialect_objc ())
7828         objc_clear_super_receiver ();
7829       block = pop_scope ();
7830     }
7831
7832   stmt = pop_stmt_list (stmt);
7833   stmt = c_build_bind_expr (block, stmt);
7834
7835   /* If this compound statement is nested immediately inside a statement
7836      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7837      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7838      STATEMENT_LISTs merge, and thus we can lose track of what statement
7839      was really last.  */
7840   if (cur_stmt_list
7841       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7842       && TREE_CODE (stmt) != BIND_EXPR)
7843     {
7844       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7845       TREE_SIDE_EFFECTS (stmt) = 1;
7846     }
7847
7848   return stmt;
7849 }
7850
7851 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7852    when the current scope is exited.  EH_ONLY is true when this is not
7853    meant to apply to normal control flow transfer.  */
7854
7855 void
7856 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7857 {
7858   enum tree_code code;
7859   tree stmt, list;
7860   bool stmt_expr;
7861
7862   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7863   stmt = build_stmt (code, NULL, cleanup);
7864   add_stmt (stmt);
7865   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7866   list = push_stmt_list ();
7867   TREE_OPERAND (stmt, 0) = list;
7868   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7869 }
7870 \f
7871 /* Build a binary-operation expression without default conversions.
7872    CODE is the kind of expression to build.
7873    This function differs from `build' in several ways:
7874    the data type of the result is computed and recorded in it,
7875    warnings are generated if arg data types are invalid,
7876    special handling for addition and subtraction of pointers is known,
7877    and some optimization is done (operations on narrow ints
7878    are done in the narrower type when that gives the same result).
7879    Constant folding is also done before the result is returned.
7880
7881    Note that the operands will never have enumeral types, or function
7882    or array types, because either they will have the default conversions
7883    performed or they have both just been converted to some other type in which
7884    the arithmetic is to be done.  */
7885
7886 tree
7887 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7888                  int convert_p)
7889 {
7890   tree type0, type1;
7891   enum tree_code code0, code1;
7892   tree op0, op1;
7893   const char *invalid_op_diag;
7894
7895   /* Expression code to give to the expression when it is built.
7896      Normally this is CODE, which is what the caller asked for,
7897      but in some special cases we change it.  */
7898   enum tree_code resultcode = code;
7899
7900   /* Data type in which the computation is to be performed.
7901      In the simplest cases this is the common type of the arguments.  */
7902   tree result_type = NULL;
7903
7904   /* Nonzero means operands have already been type-converted
7905      in whatever way is necessary.
7906      Zero means they need to be converted to RESULT_TYPE.  */
7907   int converted = 0;
7908
7909   /* Nonzero means create the expression with this type, rather than
7910      RESULT_TYPE.  */
7911   tree build_type = 0;
7912
7913   /* Nonzero means after finally constructing the expression
7914      convert it to this type.  */
7915   tree final_type = 0;
7916
7917   /* Nonzero if this is an operation like MIN or MAX which can
7918      safely be computed in short if both args are promoted shorts.
7919      Also implies COMMON.
7920      -1 indicates a bitwise operation; this makes a difference
7921      in the exact conditions for when it is safe to do the operation
7922      in a narrower mode.  */
7923   int shorten = 0;
7924
7925   /* Nonzero if this is a comparison operation;
7926      if both args are promoted shorts, compare the original shorts.
7927      Also implies COMMON.  */
7928   int short_compare = 0;
7929
7930   /* Nonzero if this is a right-shift operation, which can be computed on the
7931      original short and then promoted if the operand is a promoted short.  */
7932   int short_shift = 0;
7933
7934   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7935   int common = 0;
7936
7937   /* True means types are compatible as far as ObjC is concerned.  */
7938   bool objc_ok;
7939
7940   if (convert_p)
7941     {
7942       op0 = default_conversion (orig_op0);
7943       op1 = default_conversion (orig_op1);
7944     }
7945   else
7946     {
7947       op0 = orig_op0;
7948       op1 = orig_op1;
7949     }
7950
7951   type0 = TREE_TYPE (op0);
7952   type1 = TREE_TYPE (op1);
7953
7954   /* The expression codes of the data types of the arguments tell us
7955      whether the arguments are integers, floating, pointers, etc.  */
7956   code0 = TREE_CODE (type0);
7957   code1 = TREE_CODE (type1);
7958
7959   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7960   STRIP_TYPE_NOPS (op0);
7961   STRIP_TYPE_NOPS (op1);
7962
7963   /* If an error was already reported for one of the arguments,
7964      avoid reporting another error.  */
7965
7966   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7967     return error_mark_node;
7968
7969   if ((invalid_op_diag
7970        = targetm.invalid_binary_op (code, type0, type1)))
7971     {
7972       error (invalid_op_diag);
7973       return error_mark_node;
7974     }
7975
7976   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7977
7978   switch (code)
7979     {
7980     case PLUS_EXPR:
7981       /* Handle the pointer + int case.  */
7982       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7983         return pointer_int_sum (PLUS_EXPR, op0, op1);
7984       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7985         return pointer_int_sum (PLUS_EXPR, op1, op0);
7986       else
7987         common = 1;
7988       break;
7989
7990     case MINUS_EXPR:
7991       /* Subtraction of two similar pointers.
7992          We must subtract them as integers, then divide by object size.  */
7993       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7994           && comp_target_types (type0, type1))
7995         return pointer_diff (op0, op1);
7996       /* Handle pointer minus int.  Just like pointer plus int.  */
7997       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7998         return pointer_int_sum (MINUS_EXPR, op0, op1);
7999       else
8000         common = 1;
8001       break;
8002
8003     case MULT_EXPR:
8004       common = 1;
8005       break;
8006
8007     case TRUNC_DIV_EXPR:
8008     case CEIL_DIV_EXPR:
8009     case FLOOR_DIV_EXPR:
8010     case ROUND_DIV_EXPR:
8011     case EXACT_DIV_EXPR:
8012       warn_for_div_by_zero (op1);
8013
8014       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8015            || code0 == FIXED_POINT_TYPE
8016            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8017           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8018               || code1 == FIXED_POINT_TYPE
8019               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8020         {
8021           enum tree_code tcode0 = code0, tcode1 = code1;
8022
8023           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8024             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8025           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8026             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8027
8028           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8029               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8030             resultcode = RDIV_EXPR;
8031           else
8032             /* Although it would be tempting to shorten always here, that
8033                loses on some targets, since the modulo instruction is
8034                undefined if the quotient can't be represented in the
8035                computation mode.  We shorten only if unsigned or if
8036                dividing by something we know != -1.  */
8037             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8038                        || (TREE_CODE (op1) == INTEGER_CST
8039                            && !integer_all_onesp (op1)));
8040           common = 1;
8041         }
8042       break;
8043
8044     case BIT_AND_EXPR:
8045     case BIT_IOR_EXPR:
8046     case BIT_XOR_EXPR:
8047       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8048         shorten = -1;
8049       /* Allow vector types which are not floating point types.   */
8050       else if (code0 == VECTOR_TYPE
8051                && code1 == VECTOR_TYPE
8052                && !VECTOR_FLOAT_TYPE_P (type0)
8053                && !VECTOR_FLOAT_TYPE_P (type1))
8054         common = 1;
8055       break;
8056
8057     case TRUNC_MOD_EXPR:
8058     case FLOOR_MOD_EXPR:
8059       warn_for_div_by_zero (op1);
8060
8061       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8062         {
8063           /* Although it would be tempting to shorten always here, that loses
8064              on some targets, since the modulo instruction is undefined if the
8065              quotient can't be represented in the computation mode.  We shorten
8066              only if unsigned or if dividing by something we know != -1.  */
8067           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8068                      || (TREE_CODE (op1) == INTEGER_CST
8069                          && !integer_all_onesp (op1)));
8070           common = 1;
8071         }
8072       break;
8073
8074     case TRUTH_ANDIF_EXPR:
8075     case TRUTH_ORIF_EXPR:
8076     case TRUTH_AND_EXPR:
8077     case TRUTH_OR_EXPR:
8078     case TRUTH_XOR_EXPR:
8079       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8080            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8081            || code0 == FIXED_POINT_TYPE)
8082           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8083               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8084               || code1 == FIXED_POINT_TYPE))
8085         {
8086           /* Result of these operations is always an int,
8087              but that does not mean the operands should be
8088              converted to ints!  */
8089           result_type = integer_type_node;
8090           op0 = c_common_truthvalue_conversion (op0);
8091           op1 = c_common_truthvalue_conversion (op1);
8092           converted = 1;
8093         }
8094       break;
8095
8096       /* Shift operations: result has same type as first operand;
8097          always convert second operand to int.
8098          Also set SHORT_SHIFT if shifting rightward.  */
8099
8100     case RSHIFT_EXPR:
8101       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8102           && code1 == INTEGER_TYPE)
8103         {
8104           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8105             {
8106               if (tree_int_cst_sgn (op1) < 0)
8107                 warning (0, "right shift count is negative");
8108               else
8109                 {
8110                   if (!integer_zerop (op1))
8111                     short_shift = 1;
8112
8113                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8114                     warning (0, "right shift count >= width of type");
8115                 }
8116             }
8117
8118           /* Use the type of the value to be shifted.  */
8119           result_type = type0;
8120           /* Convert the shift-count to an integer, regardless of size
8121              of value being shifted.  */
8122           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8123             op1 = convert (integer_type_node, op1);
8124           /* Avoid converting op1 to result_type later.  */
8125           converted = 1;
8126         }
8127       break;
8128
8129     case LSHIFT_EXPR:
8130       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8131           && code1 == INTEGER_TYPE)
8132         {
8133           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8134             {
8135               if (tree_int_cst_sgn (op1) < 0)
8136                 warning (0, "left shift count is negative");
8137
8138               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8139                 warning (0, "left shift count >= width of type");
8140             }
8141
8142           /* Use the type of the value to be shifted.  */
8143           result_type = type0;
8144           /* Convert the shift-count to an integer, regardless of size
8145              of value being shifted.  */
8146           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8147             op1 = convert (integer_type_node, op1);
8148           /* Avoid converting op1 to result_type later.  */
8149           converted = 1;
8150         }
8151       break;
8152
8153     case EQ_EXPR:
8154     case NE_EXPR:
8155       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8156         warning (OPT_Wfloat_equal,
8157                  "comparing floating point with == or != is unsafe");
8158       /* Result of comparison is always int,
8159          but don't convert the args to int!  */
8160       build_type = integer_type_node;
8161       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8162            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8163           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8164               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8165         short_compare = 1;
8166       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8167         {
8168           tree tt0 = TREE_TYPE (type0);
8169           tree tt1 = TREE_TYPE (type1);
8170           /* Anything compares with void *.  void * compares with anything.
8171              Otherwise, the targets must be compatible
8172              and both must be object or both incomplete.  */
8173           if (comp_target_types (type0, type1))
8174             result_type = common_pointer_type (type0, type1);
8175           else if (VOID_TYPE_P (tt0))
8176             {
8177               /* op0 != orig_op0 detects the case of something
8178                  whose value is 0 but which isn't a valid null ptr const.  */
8179               if (pedantic && !null_pointer_constant_p (orig_op0)
8180                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8181                 pedwarn (OPT_pedantic, "ISO C forbids "
8182                          "comparison of %<void *%> with function pointer");
8183             }
8184           else if (VOID_TYPE_P (tt1))
8185             {
8186               if (pedantic && !null_pointer_constant_p (orig_op1)
8187                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8188                 pedwarn (OPT_pedantic, "ISO C forbids "
8189                          "comparison of %<void *%> with function pointer");
8190             }
8191           else
8192             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8193             if (!objc_ok)
8194               pedwarn (0, "comparison of distinct pointer types lacks a cast");
8195
8196           if (result_type == NULL_TREE)
8197             result_type = ptr_type_node;
8198         }
8199       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8200         {
8201           if (TREE_CODE (op0) == ADDR_EXPR
8202               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8203             warning (OPT_Waddress, "the address of %qD will never be NULL",
8204                      TREE_OPERAND (op0, 0));
8205           result_type = type0;
8206         }
8207       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8208         {
8209           if (TREE_CODE (op1) == ADDR_EXPR
8210               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8211             warning (OPT_Waddress, "the address of %qD will never be NULL",
8212                      TREE_OPERAND (op1, 0));
8213           result_type = type1;
8214         }
8215       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8216         {
8217           result_type = type0;
8218           pedwarn (0, "comparison between pointer and integer");
8219         }
8220       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8221         {
8222           result_type = type1;
8223           pedwarn (0, "comparison between pointer and integer");
8224         }
8225       break;
8226
8227     case LE_EXPR:
8228     case GE_EXPR:
8229     case LT_EXPR:
8230     case GT_EXPR:
8231       build_type = integer_type_node;
8232       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8233            || code0 == FIXED_POINT_TYPE)
8234           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8235               || code1 == FIXED_POINT_TYPE))
8236         short_compare = 1;
8237       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8238         {
8239           if (comp_target_types (type0, type1))
8240             {
8241               result_type = common_pointer_type (type0, type1);
8242               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8243                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8244                 pedwarn (0, "comparison of complete and incomplete pointers");
8245               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8246                 pedwarn (OPT_pedantic, "ISO C forbids "
8247                          "ordered comparisons of pointers to functions");
8248             }
8249           else
8250             {
8251               result_type = ptr_type_node;
8252               pedwarn (0, "comparison of distinct pointer types lacks a cast");
8253             }
8254         }
8255       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8256         {
8257           result_type = type0;
8258           if (pedantic)
8259             pedwarn (OPT_pedantic,
8260                      "ordered comparison of pointer with integer zero");
8261           else if (extra_warnings)
8262             warning (OPT_Wextra,
8263                      "ordered comparison of pointer with integer zero");
8264         }
8265       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8266         {
8267           result_type = type1;
8268           pedwarn (OPT_pedantic,
8269                    "ordered comparison of pointer with integer zero");
8270         }
8271       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8272         {
8273           result_type = type0;
8274           pedwarn (0, "comparison between pointer and integer");
8275         }
8276       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8277         {
8278           result_type = type1;
8279           pedwarn (0, "comparison between pointer and integer");
8280         }
8281       break;
8282
8283     default:
8284       gcc_unreachable ();
8285     }
8286
8287   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8288     return error_mark_node;
8289
8290   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8291       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8292           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8293                                                     TREE_TYPE (type1))))
8294     {
8295       binary_op_error (code, type0, type1);
8296       return error_mark_node;
8297     }
8298
8299   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8300        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8301       &&
8302       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8303        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8304     {
8305       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8306
8307       if (shorten || common || short_compare)
8308         {
8309           result_type = c_common_type (type0, type1);
8310           if (result_type == error_mark_node)
8311             return error_mark_node;
8312         }
8313
8314       /* For certain operations (which identify themselves by shorten != 0)
8315          if both args were extended from the same smaller type,
8316          do the arithmetic in that type and then extend.
8317
8318          shorten !=0 and !=1 indicates a bitwise operation.
8319          For them, this optimization is safe only if
8320          both args are zero-extended or both are sign-extended.
8321          Otherwise, we might change the result.
8322          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8323          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8324
8325       if (shorten && none_complex)
8326         {
8327           final_type = result_type;
8328           result_type = shorten_binary_op (result_type, op0, op1,
8329                                            shorten == -1);
8330         }
8331
8332       /* Shifts can be shortened if shifting right.  */
8333
8334       if (short_shift)
8335         {
8336           int unsigned_arg;
8337           tree arg0 = get_narrower (op0, &unsigned_arg);
8338
8339           final_type = result_type;
8340
8341           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8342             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8343
8344           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8345               /* We can shorten only if the shift count is less than the
8346                  number of bits in the smaller type size.  */
8347               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8348               /* We cannot drop an unsigned shift after sign-extension.  */
8349               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8350             {
8351               /* Do an unsigned shift if the operand was zero-extended.  */
8352               result_type
8353                 = c_common_signed_or_unsigned_type (unsigned_arg,
8354                                                     TREE_TYPE (arg0));
8355               /* Convert value-to-be-shifted to that type.  */
8356               if (TREE_TYPE (op0) != result_type)
8357                 op0 = convert (result_type, op0);
8358               converted = 1;
8359             }
8360         }
8361
8362       /* Comparison operations are shortened too but differently.
8363          They identify themselves by setting short_compare = 1.  */
8364
8365       if (short_compare)
8366         {
8367           /* Don't write &op0, etc., because that would prevent op0
8368              from being kept in a register.
8369              Instead, make copies of the our local variables and
8370              pass the copies by reference, then copy them back afterward.  */
8371           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8372           enum tree_code xresultcode = resultcode;
8373           tree val
8374             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8375
8376           if (val != 0)
8377             return val;
8378
8379           op0 = xop0, op1 = xop1;
8380           converted = 1;
8381           resultcode = xresultcode;
8382
8383           if (warn_sign_compare && !skip_evaluation)
8384             {
8385               warn_for_sign_compare (orig_op0, orig_op1, op0, op1,
8386                                      result_type, resultcode);
8387             }
8388         }
8389     }
8390
8391   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8392      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8393      Then the expression will be built.
8394      It will be given type FINAL_TYPE if that is nonzero;
8395      otherwise, it will be given type RESULT_TYPE.  */
8396
8397   if (!result_type)
8398     {
8399       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8400       return error_mark_node;
8401     }
8402
8403   if (!converted)
8404     {
8405       if (TREE_TYPE (op0) != result_type)
8406         op0 = convert_and_check (result_type, op0);
8407       if (TREE_TYPE (op1) != result_type)
8408         op1 = convert_and_check (result_type, op1);
8409
8410       /* This can happen if one operand has a vector type, and the other
8411          has a different type.  */
8412       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8413         return error_mark_node;
8414     }
8415
8416   if (build_type == NULL_TREE)
8417     build_type = result_type;
8418
8419   {
8420     /* Treat expressions in initializers specially as they can't trap.  */
8421     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8422                                                                     build_type,
8423                                                                     op0, op1)
8424                                          : fold_build2 (resultcode, build_type,
8425                                                         op0, op1);
8426
8427     if (final_type != 0)
8428       result = convert (final_type, result);
8429     return result;
8430   }
8431 }
8432
8433
8434 /* Convert EXPR to be a truth-value, validating its type for this
8435    purpose.  */
8436
8437 tree
8438 c_objc_common_truthvalue_conversion (tree expr)
8439 {
8440   switch (TREE_CODE (TREE_TYPE (expr)))
8441     {
8442     case ARRAY_TYPE:
8443       error ("used array that cannot be converted to pointer where scalar is required");
8444       return error_mark_node;
8445
8446     case RECORD_TYPE:
8447       error ("used struct type value where scalar is required");
8448       return error_mark_node;
8449
8450     case UNION_TYPE:
8451       error ("used union type value where scalar is required");
8452       return error_mark_node;
8453
8454     case FUNCTION_TYPE:
8455       gcc_unreachable ();
8456
8457     default:
8458       break;
8459     }
8460
8461   /* ??? Should we also give an error for void and vectors rather than
8462      leaving those to give errors later?  */
8463   return c_common_truthvalue_conversion (expr);
8464 }
8465 \f
8466
8467 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8468    required.  */
8469
8470 tree
8471 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8472 {
8473   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8474     {
8475       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8476       /* Executing a compound literal inside a function reinitializes
8477          it.  */
8478       if (!TREE_STATIC (decl))
8479         *se = true;
8480       return decl;
8481     }
8482   else
8483     return expr;
8484 }
8485 \f
8486 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8487
8488 tree
8489 c_begin_omp_parallel (void)
8490 {
8491   tree block;
8492
8493   keep_next_level ();
8494   block = c_begin_compound_stmt (true);
8495
8496   return block;
8497 }
8498
8499 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8500
8501 tree
8502 c_finish_omp_parallel (tree clauses, tree block)
8503 {
8504   tree stmt;
8505
8506   block = c_end_compound_stmt (block, true);
8507
8508   stmt = make_node (OMP_PARALLEL);
8509   TREE_TYPE (stmt) = void_type_node;
8510   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8511   OMP_PARALLEL_BODY (stmt) = block;
8512
8513   return add_stmt (stmt);
8514 }
8515
8516 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8517
8518 tree
8519 c_begin_omp_task (void)
8520 {
8521   tree block;
8522
8523   keep_next_level ();
8524   block = c_begin_compound_stmt (true);
8525
8526   return block;
8527 }
8528
8529 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8530
8531 tree
8532 c_finish_omp_task (tree clauses, tree block)
8533 {
8534   tree stmt;
8535
8536   block = c_end_compound_stmt (block, true);
8537
8538   stmt = make_node (OMP_TASK);
8539   TREE_TYPE (stmt) = void_type_node;
8540   OMP_TASK_CLAUSES (stmt) = clauses;
8541   OMP_TASK_BODY (stmt) = block;
8542
8543   return add_stmt (stmt);
8544 }
8545
8546 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8547    Remove any elements from the list that are invalid.  */
8548
8549 tree
8550 c_finish_omp_clauses (tree clauses)
8551 {
8552   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8553   tree c, t, *pc = &clauses;
8554   const char *name;
8555
8556   bitmap_obstack_initialize (NULL);
8557   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8558   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8559   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8560
8561   for (pc = &clauses, c = clauses; c ; c = *pc)
8562     {
8563       bool remove = false;
8564       bool need_complete = false;
8565       bool need_implicitly_determined = false;
8566
8567       switch (OMP_CLAUSE_CODE (c))
8568         {
8569         case OMP_CLAUSE_SHARED:
8570           name = "shared";
8571           need_implicitly_determined = true;
8572           goto check_dup_generic;
8573
8574         case OMP_CLAUSE_PRIVATE:
8575           name = "private";
8576           need_complete = true;
8577           need_implicitly_determined = true;
8578           goto check_dup_generic;
8579
8580         case OMP_CLAUSE_REDUCTION:
8581           name = "reduction";
8582           need_implicitly_determined = true;
8583           t = OMP_CLAUSE_DECL (c);
8584           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8585               || POINTER_TYPE_P (TREE_TYPE (t)))
8586             {
8587               error ("%qE has invalid type for %<reduction%>", t);
8588               remove = true;
8589             }
8590           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8591             {
8592               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8593               const char *r_name = NULL;
8594
8595               switch (r_code)
8596                 {
8597                 case PLUS_EXPR:
8598                 case MULT_EXPR:
8599                 case MINUS_EXPR:
8600                   break;
8601                 case BIT_AND_EXPR:
8602                   r_name = "&";
8603                   break;
8604                 case BIT_XOR_EXPR:
8605                   r_name = "^";
8606                   break;
8607                 case BIT_IOR_EXPR:
8608                   r_name = "|";
8609                   break;
8610                 case TRUTH_ANDIF_EXPR:
8611                   r_name = "&&";
8612                   break;
8613                 case TRUTH_ORIF_EXPR:
8614                   r_name = "||";
8615                   break;
8616                 default:
8617                   gcc_unreachable ();
8618                 }
8619               if (r_name)
8620                 {
8621                   error ("%qE has invalid type for %<reduction(%s)%>",
8622                          t, r_name);
8623                   remove = true;
8624                 }
8625             }
8626           goto check_dup_generic;
8627
8628         case OMP_CLAUSE_COPYPRIVATE:
8629           name = "copyprivate";
8630           goto check_dup_generic;
8631
8632         case OMP_CLAUSE_COPYIN:
8633           name = "copyin";
8634           t = OMP_CLAUSE_DECL (c);
8635           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8636             {
8637               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8638               remove = true;
8639             }
8640           goto check_dup_generic;
8641
8642         check_dup_generic:
8643           t = OMP_CLAUSE_DECL (c);
8644           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8645             {
8646               error ("%qE is not a variable in clause %qs", t, name);
8647               remove = true;
8648             }
8649           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8650                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8651                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8652             {
8653               error ("%qE appears more than once in data clauses", t);
8654               remove = true;
8655             }
8656           else
8657             bitmap_set_bit (&generic_head, DECL_UID (t));
8658           break;
8659
8660         case OMP_CLAUSE_FIRSTPRIVATE:
8661           name = "firstprivate";
8662           t = OMP_CLAUSE_DECL (c);
8663           need_complete = true;
8664           need_implicitly_determined = true;
8665           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8666             {
8667               error ("%qE is not a variable in clause %<firstprivate%>", t);
8668               remove = true;
8669             }
8670           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8671                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8672             {
8673               error ("%qE appears more than once in data clauses", t);
8674               remove = true;
8675             }
8676           else
8677             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8678           break;
8679
8680         case OMP_CLAUSE_LASTPRIVATE:
8681           name = "lastprivate";
8682           t = OMP_CLAUSE_DECL (c);
8683           need_complete = true;
8684           need_implicitly_determined = true;
8685           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8686             {
8687               error ("%qE is not a variable in clause %<lastprivate%>", t);
8688               remove = true;
8689             }
8690           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8691                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8692             {
8693               error ("%qE appears more than once in data clauses", t);
8694               remove = true;
8695             }
8696           else
8697             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8698           break;
8699
8700         case OMP_CLAUSE_IF:
8701         case OMP_CLAUSE_NUM_THREADS:
8702         case OMP_CLAUSE_SCHEDULE:
8703         case OMP_CLAUSE_NOWAIT:
8704         case OMP_CLAUSE_ORDERED:
8705         case OMP_CLAUSE_DEFAULT:
8706         case OMP_CLAUSE_UNTIED:
8707         case OMP_CLAUSE_COLLAPSE:
8708           pc = &OMP_CLAUSE_CHAIN (c);
8709           continue;
8710
8711         default:
8712           gcc_unreachable ();
8713         }
8714
8715       if (!remove)
8716         {
8717           t = OMP_CLAUSE_DECL (c);
8718
8719           if (need_complete)
8720             {
8721               t = require_complete_type (t);
8722               if (t == error_mark_node)
8723                 remove = true;
8724             }
8725
8726           if (need_implicitly_determined)
8727             {
8728               const char *share_name = NULL;
8729
8730               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8731                 share_name = "threadprivate";
8732               else switch (c_omp_predetermined_sharing (t))
8733                 {
8734                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8735                   break;
8736                 case OMP_CLAUSE_DEFAULT_SHARED:
8737                   share_name = "shared";
8738                   break;
8739                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8740                   share_name = "private";
8741                   break;
8742                 default:
8743                   gcc_unreachable ();
8744                 }
8745               if (share_name)
8746                 {
8747                   error ("%qE is predetermined %qs for %qs",
8748                          t, share_name, name);
8749                   remove = true;
8750                 }
8751             }
8752         }
8753
8754       if (remove)
8755         *pc = OMP_CLAUSE_CHAIN (c);
8756       else
8757         pc = &OMP_CLAUSE_CHAIN (c);
8758     }
8759
8760   bitmap_obstack_release (NULL);
8761   return clauses;
8762 }
8763
8764 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8765    down to the element type of an array.  */
8766
8767 tree
8768 c_build_qualified_type (tree type, int type_quals)
8769 {
8770   if (type == error_mark_node)
8771     return type;
8772
8773   if (TREE_CODE (type) == ARRAY_TYPE)
8774     {
8775       tree t;
8776       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8777                                                   type_quals);
8778
8779       /* See if we already have an identically qualified type.  */
8780       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8781         {
8782           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8783               && TYPE_NAME (t) == TYPE_NAME (type)
8784               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8785               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8786                                        TYPE_ATTRIBUTES (type)))
8787             break;
8788         }
8789       if (!t)
8790         {
8791           tree domain = TYPE_DOMAIN (type);
8792
8793           t = build_variant_type_copy (type);
8794           TREE_TYPE (t) = element_type;
8795
8796           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8797               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8798             SET_TYPE_STRUCTURAL_EQUALITY (t);
8799           else if (TYPE_CANONICAL (element_type) != element_type
8800                    || (domain && TYPE_CANONICAL (domain) != domain))
8801             {
8802               tree unqualified_canon
8803                 = build_array_type (TYPE_CANONICAL (element_type),
8804                                     domain? TYPE_CANONICAL (domain)
8805                                           : NULL_TREE);
8806               TYPE_CANONICAL (t)
8807                 = c_build_qualified_type (unqualified_canon, type_quals);
8808             }
8809           else
8810             TYPE_CANONICAL (t) = t;
8811         }
8812       return t;
8813     }
8814
8815   /* A restrict-qualified pointer type must be a pointer to object or
8816      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8817      REFERENCE_TYPEs, which is appropriate for C++.  */
8818   if ((type_quals & TYPE_QUAL_RESTRICT)
8819       && (!POINTER_TYPE_P (type)
8820           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8821     {
8822       error ("invalid use of %<restrict%>");
8823       type_quals &= ~TYPE_QUAL_RESTRICT;
8824     }
8825
8826   return build_qualified_type (type, type_quals);
8827 }