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 (input_location, 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 (input_location, 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 (input_location, 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 (input_location, 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 (input_location, OPT_pedantic,
2119                      "ISO C forbids subscripting %<register%> array");
2120           else if (!flag_isoc99 && !lvalue_p (foo))
2121             pedwarn (input_location, 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 (loc, 0, "%qD is static but used in inline function %qD "
2237              "which is not static", 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 (input_location, "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 (input_location, 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 (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2806              "pointer of type %<void *%> used in subtraction");
2807   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2808     pedwarn (input_location, 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 (input_location, 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 (input_location, OPT_pedantic,
3024                    "ISO C does not support %<++%> and %<--%> 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 (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3074                            "wrong type argument to increment");
3075                 else
3076                   pedwarn (input_location, 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 (input_location, 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 (input_location, 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 (input_location, OPT_pedantic,
3476                      "ISO C forbids conditional expr between "
3477                      "%<void *%> and function pointer");
3478           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3479                                                           TREE_TYPE (type2)));
3480         }
3481       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3482         {
3483           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3484             pedwarn (input_location, OPT_pedantic,
3485                      "ISO C forbids conditional expr between "
3486                      "%<void *%> and function pointer");
3487           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3488                                                           TREE_TYPE (type1)));
3489         }
3490       else
3491         {
3492           pedwarn (input_location, 0,
3493                    "pointer type mismatch in conditional expression");
3494           result_type = build_pointer_type (void_type_node);
3495         }
3496     }
3497   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3498     {
3499       if (!null_pointer_constant_p (orig_op2))
3500         pedwarn (input_location, 0,
3501                  "pointer/integer type mismatch in conditional expression");
3502       else
3503         {
3504           op2 = null_pointer_node;
3505         }
3506       result_type = type1;
3507     }
3508   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3509     {
3510       if (!null_pointer_constant_p (orig_op1))
3511         pedwarn (input_location, 0,
3512                  "pointer/integer type mismatch in conditional expression");
3513       else
3514         {
3515           op1 = null_pointer_node;
3516         }
3517       result_type = type2;
3518     }
3519
3520   if (!result_type)
3521     {
3522       if (flag_cond_mismatch)
3523         result_type = void_type_node;
3524       else
3525         {
3526           error ("type mismatch in conditional expression");
3527           return error_mark_node;
3528         }
3529     }
3530
3531   /* Merge const and volatile flags of the incoming types.  */
3532   result_type
3533     = build_type_variant (result_type,
3534                           TREE_READONLY (op1) || TREE_READONLY (op2),
3535                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3536
3537   if (result_type != TREE_TYPE (op1))
3538     op1 = convert_and_check (result_type, op1);
3539   if (result_type != TREE_TYPE (op2))
3540     op2 = convert_and_check (result_type, op2);
3541
3542   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3543 }
3544 \f
3545 /* Return a compound expression that performs two expressions and
3546    returns the value of the second of them.  */
3547
3548 tree
3549 build_compound_expr (tree expr1, tree expr2)
3550 {
3551   if (!TREE_SIDE_EFFECTS (expr1))
3552     {
3553       /* The left-hand operand of a comma expression is like an expression
3554          statement: with -Wunused, we should warn if it doesn't have
3555          any side-effects, unless it was explicitly cast to (void).  */
3556       if (warn_unused_value)
3557         {
3558           if (VOID_TYPE_P (TREE_TYPE (expr1))
3559               && CONVERT_EXPR_P (expr1))
3560             ; /* (void) a, b */
3561           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3562                    && TREE_CODE (expr1) == COMPOUND_EXPR
3563                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3564             ; /* (void) a, (void) b, c */
3565           else
3566             warning (OPT_Wunused_value,
3567                      "left-hand operand of comma expression has no effect");
3568         }
3569     }
3570
3571   /* With -Wunused, we should also warn if the left-hand operand does have
3572      side-effects, but computes a value which is not used.  For example, in
3573      `foo() + bar(), baz()' the result of the `+' operator is not used,
3574      so we should issue a warning.  */
3575   else if (warn_unused_value)
3576     warn_if_unused_value (expr1, input_location);
3577
3578   if (expr2 == error_mark_node)
3579     return error_mark_node;
3580
3581   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3582 }
3583
3584 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3585
3586 tree
3587 build_c_cast (tree type, tree expr)
3588 {
3589   tree value = expr;
3590
3591   if (type == error_mark_node || expr == error_mark_node)
3592     return error_mark_node;
3593
3594   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3595      only in <protocol> qualifications.  But when constructing cast expressions,
3596      the protocols do matter and must be kept around.  */
3597   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3598     return build1 (NOP_EXPR, type, expr);
3599
3600   type = TYPE_MAIN_VARIANT (type);
3601
3602   if (TREE_CODE (type) == ARRAY_TYPE)
3603     {
3604       error ("cast specifies array type");
3605       return error_mark_node;
3606     }
3607
3608   if (TREE_CODE (type) == FUNCTION_TYPE)
3609     {
3610       error ("cast specifies function type");
3611       return error_mark_node;
3612     }
3613
3614   if (!VOID_TYPE_P (type))
3615     {
3616       value = require_complete_type (value);
3617       if (value == error_mark_node)
3618         return error_mark_node;
3619     }
3620
3621   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3622     {
3623       if (TREE_CODE (type) == RECORD_TYPE
3624           || TREE_CODE (type) == UNION_TYPE)
3625         pedwarn (input_location, OPT_pedantic,
3626                  "ISO C forbids casting nonscalar to the same type");
3627     }
3628   else if (TREE_CODE (type) == UNION_TYPE)
3629     {
3630       tree field;
3631
3632       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3633         if (TREE_TYPE (field) != error_mark_node
3634             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3635                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3636           break;
3637
3638       if (field)
3639         {
3640           tree t;
3641
3642           pedwarn (input_location, OPT_pedantic,
3643                    "ISO C forbids casts to union type");
3644           t = digest_init (type,
3645                            build_constructor_single (type, field, value),
3646                            true, 0);
3647           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3648           return t;
3649         }
3650       error ("cast to union type from type not present in union");
3651       return error_mark_node;
3652     }
3653   else
3654     {
3655       tree otype, ovalue;
3656
3657       if (type == void_type_node)
3658         return build1 (CONVERT_EXPR, type, value);
3659
3660       otype = TREE_TYPE (value);
3661
3662       /* Optionally warn about potentially worrisome casts.  */
3663
3664       if (warn_cast_qual
3665           && TREE_CODE (type) == POINTER_TYPE
3666           && TREE_CODE (otype) == POINTER_TYPE)
3667         {
3668           tree in_type = type;
3669           tree in_otype = otype;
3670           int added = 0;
3671           int discarded = 0;
3672
3673           /* Check that the qualifiers on IN_TYPE are a superset of
3674              the qualifiers of IN_OTYPE.  The outermost level of
3675              POINTER_TYPE nodes is uninteresting and we stop as soon
3676              as we hit a non-POINTER_TYPE node on either type.  */
3677           do
3678             {
3679               in_otype = TREE_TYPE (in_otype);
3680               in_type = TREE_TYPE (in_type);
3681
3682               /* GNU C allows cv-qualified function types.  'const'
3683                  means the function is very pure, 'volatile' means it
3684                  can't return.  We need to warn when such qualifiers
3685                  are added, not when they're taken away.  */
3686               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3687                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3688                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3689               else
3690                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3691             }
3692           while (TREE_CODE (in_type) == POINTER_TYPE
3693                  && TREE_CODE (in_otype) == POINTER_TYPE);
3694
3695           if (added)
3696             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3697
3698           if (discarded)
3699             /* There are qualifiers present in IN_OTYPE that are not
3700                present in IN_TYPE.  */
3701             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3702         }
3703
3704       /* Warn about possible alignment problems.  */
3705       if (STRICT_ALIGNMENT
3706           && TREE_CODE (type) == POINTER_TYPE
3707           && TREE_CODE (otype) == POINTER_TYPE
3708           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3709           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3710           /* Don't warn about opaque types, where the actual alignment
3711              restriction is unknown.  */
3712           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3713                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3714                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3715           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3716         warning (OPT_Wcast_align,
3717                  "cast increases required alignment of target type");
3718
3719       if (TREE_CODE (type) == INTEGER_TYPE
3720           && TREE_CODE (otype) == POINTER_TYPE
3721           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3722       /* Unlike conversion of integers to pointers, where the
3723          warning is disabled for converting constants because
3724          of cases such as SIG_*, warn about converting constant
3725          pointers to integers. In some cases it may cause unwanted
3726          sign extension, and a warning is appropriate.  */
3727         warning (OPT_Wpointer_to_int_cast,
3728                  "cast from pointer to integer of different size");
3729
3730       if (TREE_CODE (value) == CALL_EXPR
3731           && TREE_CODE (type) != TREE_CODE (otype))
3732         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3733                  "to non-matching type %qT", otype, type);
3734
3735       if (TREE_CODE (type) == POINTER_TYPE
3736           && TREE_CODE (otype) == INTEGER_TYPE
3737           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3738           /* Don't warn about converting any constant.  */
3739           && !TREE_CONSTANT (value))
3740         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3741                  "of different size");
3742
3743       if (warn_strict_aliasing <= 2)
3744         strict_aliasing_warning (otype, type, expr);
3745
3746       /* If pedantic, warn for conversions between function and object
3747          pointer types, except for converting a null pointer constant
3748          to function pointer type.  */
3749       if (pedantic
3750           && TREE_CODE (type) == POINTER_TYPE
3751           && TREE_CODE (otype) == POINTER_TYPE
3752           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3753           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3754         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3755                  "conversion of function pointer to object pointer type");
3756
3757       if (pedantic
3758           && TREE_CODE (type) == POINTER_TYPE
3759           && TREE_CODE (otype) == POINTER_TYPE
3760           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3761           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3762           && !null_pointer_constant_p (value))
3763         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3764                  "conversion of object pointer to function pointer type");
3765
3766       ovalue = value;
3767       value = convert (type, value);
3768
3769       /* Ignore any integer overflow caused by the cast.  */
3770       if (TREE_CODE (value) == INTEGER_CST)
3771         {
3772           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3773             {
3774               if (!TREE_OVERFLOW (value))
3775                 {
3776                   /* Avoid clobbering a shared constant.  */
3777                   value = copy_node (value);
3778                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3779                 }
3780             }
3781           else if (TREE_OVERFLOW (value))
3782             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3783             value = build_int_cst_wide (TREE_TYPE (value),
3784                                         TREE_INT_CST_LOW (value),
3785                                         TREE_INT_CST_HIGH (value));
3786         }
3787     }
3788
3789   /* Don't let a cast be an lvalue.  */
3790   if (value == expr)
3791     value = non_lvalue (value);
3792
3793   return value;
3794 }
3795
3796 /* Interpret a cast of expression EXPR to type TYPE.  */
3797 tree
3798 c_cast_expr (struct c_type_name *type_name, tree expr)
3799 {
3800   tree type;
3801   int saved_wsp = warn_strict_prototypes;
3802
3803   /* This avoids warnings about unprototyped casts on
3804      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3805   if (TREE_CODE (expr) == INTEGER_CST)
3806     warn_strict_prototypes = 0;
3807   type = groktypename (type_name);
3808   warn_strict_prototypes = saved_wsp;
3809
3810   return build_c_cast (type, expr);
3811 }
3812 \f
3813 /* Build an assignment expression of lvalue LHS from value RHS.
3814    MODIFYCODE is the code for a binary operator that we use
3815    to combine the old value of LHS with RHS to get the new value.
3816    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3817
3818 tree
3819 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3820 {
3821   tree result;
3822   tree newrhs;
3823   tree lhstype = TREE_TYPE (lhs);
3824   tree olhstype = lhstype;
3825
3826   /* Types that aren't fully specified cannot be used in assignments.  */
3827   lhs = require_complete_type (lhs);
3828
3829   /* Avoid duplicate error messages from operands that had errors.  */
3830   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3831     return error_mark_node;
3832
3833   if (!lvalue_or_else (lhs, lv_assign))
3834     return error_mark_node;
3835
3836   STRIP_TYPE_NOPS (rhs);
3837
3838   newrhs = rhs;
3839
3840   /* If a binary op has been requested, combine the old LHS value with the RHS
3841      producing the value we should actually store into the LHS.  */
3842
3843   if (modifycode != NOP_EXPR)
3844     {
3845       lhs = stabilize_reference (lhs);
3846       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3847     }
3848
3849   /* Give an error for storing in something that is 'const'.  */
3850
3851   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3852       || ((TREE_CODE (lhstype) == RECORD_TYPE
3853            || TREE_CODE (lhstype) == UNION_TYPE)
3854           && C_TYPE_FIELDS_READONLY (lhstype)))
3855     {
3856       readonly_error (lhs, lv_assign);
3857       return error_mark_node;
3858     }
3859
3860   /* If storing into a structure or union member,
3861      it has probably been given type `int'.
3862      Compute the type that would go with
3863      the actual amount of storage the member occupies.  */
3864
3865   if (TREE_CODE (lhs) == COMPONENT_REF
3866       && (TREE_CODE (lhstype) == INTEGER_TYPE
3867           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3868           || TREE_CODE (lhstype) == REAL_TYPE
3869           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3870     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3871
3872   /* If storing in a field that is in actuality a short or narrower than one,
3873      we must store in the field in its actual type.  */
3874
3875   if (lhstype != TREE_TYPE (lhs))
3876     {
3877       lhs = copy_node (lhs);
3878       TREE_TYPE (lhs) = lhstype;
3879     }
3880
3881   /* Convert new value to destination type.  */
3882
3883   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3884                                    NULL_TREE, NULL_TREE, 0);
3885   if (TREE_CODE (newrhs) == ERROR_MARK)
3886     return error_mark_node;
3887
3888   /* Emit ObjC write barrier, if necessary.  */
3889   if (c_dialect_objc () && flag_objc_gc)
3890     {
3891       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3892       if (result)
3893         return result;
3894     }
3895
3896   /* Scan operands.  */
3897
3898   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3899   TREE_SIDE_EFFECTS (result) = 1;
3900
3901   /* If we got the LHS in a different type for storing in,
3902      convert the result back to the nominal type of LHS
3903      so that the value we return always has the same type
3904      as the LHS argument.  */
3905
3906   if (olhstype == TREE_TYPE (result))
3907     return result;
3908   return convert_for_assignment (olhstype, result, ic_assign,
3909                                  NULL_TREE, NULL_TREE, 0);
3910 }
3911 \f
3912 /* Convert value RHS to type TYPE as preparation for an assignment
3913    to an lvalue of type TYPE.
3914    The real work of conversion is done by `convert'.
3915    The purpose of this function is to generate error messages
3916    for assignments that are not allowed in C.
3917    ERRTYPE says whether it is argument passing, assignment,
3918    initialization or return.
3919
3920    FUNCTION is a tree for the function being called.
3921    PARMNUM is the number of the argument, for printing in error messages.  */
3922
3923 static tree
3924 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3925                         tree fundecl, tree function, int parmnum)
3926 {
3927   enum tree_code codel = TREE_CODE (type);
3928   tree rhstype;
3929   enum tree_code coder;
3930   tree rname = NULL_TREE;
3931   bool objc_ok = false;
3932
3933   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3934     {
3935       tree selector;
3936       /* Change pointer to function to the function itself for
3937          diagnostics.  */
3938       if (TREE_CODE (function) == ADDR_EXPR
3939           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3940         function = TREE_OPERAND (function, 0);
3941
3942       /* Handle an ObjC selector specially for diagnostics.  */
3943       selector = objc_message_selector ();
3944       rname = function;
3945       if (selector && parmnum > 2)
3946         {
3947           rname = selector;
3948           parmnum -= 2;
3949         }
3950     }
3951
3952   /* This macro is used to emit diagnostics to ensure that all format
3953      strings are complete sentences, visible to gettext and checked at
3954      compile time.  */
3955 #define WARN_FOR_ASSIGNMENT(LOCATION, AR, AS, IN, RE)   \
3956   do {                                          \
3957     switch (errtype)                            \
3958       {                                         \
3959       case ic_argpass:                          \
3960         pedwarn (LOCATION, 0, AR, parmnum, rname);      \
3961         break;                                  \
3962       case ic_argpass_nonproto:                 \
3963         warning (0, AR, parmnum, rname);        \
3964         break;                                  \
3965       case ic_assign:                           \
3966         pedwarn (LOCATION, 0, AS);                      \
3967         break;                                  \
3968       case ic_init:                             \
3969         pedwarn (LOCATION, 0, IN);                      \
3970         break;                                  \
3971       case ic_return:                           \
3972         pedwarn (LOCATION, 0, RE);                      \
3973         break;                                  \
3974       default:                                  \
3975         gcc_unreachable ();                     \
3976       }                                         \
3977   } while (0)
3978
3979   STRIP_TYPE_NOPS (rhs);
3980
3981   if (optimize && TREE_CODE (rhs) == VAR_DECL
3982            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3983     rhs = decl_constant_value_for_broken_optimization (rhs);
3984
3985   rhstype = TREE_TYPE (rhs);
3986   coder = TREE_CODE (rhstype);
3987
3988   if (coder == ERROR_MARK)
3989     return error_mark_node;
3990
3991   if (c_dialect_objc ())
3992     {
3993       int parmno;
3994
3995       switch (errtype)
3996         {
3997         case ic_return:
3998           parmno = 0;
3999           break;
4000
4001         case ic_assign:
4002           parmno = -1;
4003           break;
4004
4005         case ic_init:
4006           parmno = -2;
4007           break;
4008
4009         default:
4010           parmno = parmnum;
4011           break;
4012         }
4013
4014       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4015     }
4016
4017   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4018     return rhs;
4019
4020   if (coder == VOID_TYPE)
4021     {
4022       /* Except for passing an argument to an unprototyped function,
4023          this is a constraint violation.  When passing an argument to
4024          an unprototyped function, it is compile-time undefined;
4025          making it a constraint in that case was rejected in
4026          DR#252.  */
4027       error ("void value not ignored as it ought to be");
4028       return error_mark_node;
4029     }
4030   rhs = require_complete_type (rhs);
4031   if (rhs == error_mark_node)
4032     return error_mark_node;
4033   /* A type converts to a reference to it.
4034      This code doesn't fully support references, it's just for the
4035      special case of va_start and va_copy.  */
4036   if (codel == REFERENCE_TYPE
4037       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4038     {
4039       if (!lvalue_p (rhs))
4040         {
4041           error ("cannot pass rvalue to reference parameter");
4042           return error_mark_node;
4043         }
4044       if (!c_mark_addressable (rhs))
4045         return error_mark_node;
4046       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4047
4048       /* We already know that these two types are compatible, but they
4049          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4050          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4051          likely to be va_list, a typedef to __builtin_va_list, which
4052          is different enough that it will cause problems later.  */
4053       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4054         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4055
4056       rhs = build1 (NOP_EXPR, type, rhs);
4057       return rhs;
4058     }
4059   /* Some types can interconvert without explicit casts.  */
4060   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4061            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4062     return convert (type, rhs);
4063   /* Arithmetic types all interconvert, and enum is treated like int.  */
4064   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4065             || codel == FIXED_POINT_TYPE
4066             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4067             || codel == BOOLEAN_TYPE)
4068            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4069                || coder == FIXED_POINT_TYPE
4070                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4071                || coder == BOOLEAN_TYPE))
4072     return convert_and_check (type, rhs);
4073
4074   /* Aggregates in different TUs might need conversion.  */
4075   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4076       && codel == coder
4077       && comptypes (type, rhstype))
4078     return convert_and_check (type, rhs);
4079
4080   /* Conversion to a transparent union from its member types.
4081      This applies only to function arguments.  */
4082   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4083       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4084     {
4085       tree memb, marginal_memb = NULL_TREE;
4086
4087       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4088         {
4089           tree memb_type = TREE_TYPE (memb);
4090
4091           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4092                          TYPE_MAIN_VARIANT (rhstype)))
4093             break;
4094
4095           if (TREE_CODE (memb_type) != POINTER_TYPE)
4096             continue;
4097
4098           if (coder == POINTER_TYPE)
4099             {
4100               tree ttl = TREE_TYPE (memb_type);
4101               tree ttr = TREE_TYPE (rhstype);
4102
4103               /* Any non-function converts to a [const][volatile] void *
4104                  and vice versa; otherwise, targets must be the same.
4105                  Meanwhile, the lhs target must have all the qualifiers of
4106                  the rhs.  */
4107               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4108                   || comp_target_types (memb_type, rhstype))
4109                 {
4110                   /* If this type won't generate any warnings, use it.  */
4111                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4112                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4113                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4114                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4115                              == TYPE_QUALS (ttr))
4116                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4117                              == TYPE_QUALS (ttl))))
4118                     break;
4119
4120                   /* Keep looking for a better type, but remember this one.  */
4121                   if (!marginal_memb)
4122                     marginal_memb = memb;
4123                 }
4124             }
4125
4126           /* Can convert integer zero to any pointer type.  */
4127           if (null_pointer_constant_p (rhs))
4128             {
4129               rhs = null_pointer_node;
4130               break;
4131             }
4132         }
4133
4134       if (memb || marginal_memb)
4135         {
4136           if (!memb)
4137             {
4138               /* We have only a marginally acceptable member type;
4139                  it needs a warning.  */
4140               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4141               tree ttr = TREE_TYPE (rhstype);
4142
4143               /* Const and volatile mean something different for function
4144                  types, so the usual warnings are not appropriate.  */
4145               if (TREE_CODE (ttr) == FUNCTION_TYPE
4146                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4147                 {
4148                   /* Because const and volatile on functions are
4149                      restrictions that say the function will not do
4150                      certain things, it is okay to use a const or volatile
4151                      function where an ordinary one is wanted, but not
4152                      vice-versa.  */
4153                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4154                     WARN_FOR_ASSIGNMENT (input_location,
4155                                          G_("passing argument %d of %qE "
4156                                             "makes qualified function "
4157                                             "pointer from unqualified"),
4158                                          G_("assignment makes qualified "
4159                                             "function pointer from "
4160                                             "unqualified"),
4161                                          G_("initialization makes qualified "
4162                                             "function pointer from "
4163                                             "unqualified"),
4164                                          G_("return makes qualified function "
4165                                             "pointer from unqualified"));
4166                 }
4167               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4168                 WARN_FOR_ASSIGNMENT (input_location,
4169                                      G_("passing argument %d of %qE discards "
4170                                         "qualifiers from pointer target type"),
4171                                      G_("assignment discards qualifiers "
4172                                         "from pointer target type"),
4173                                      G_("initialization discards qualifiers "
4174                                         "from pointer target type"),
4175                                      G_("return discards qualifiers from "
4176                                         "pointer target type"));
4177
4178               memb = marginal_memb;
4179             }
4180
4181           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4182             pedwarn (input_location, OPT_pedantic,
4183                      "ISO C prohibits argument conversion to union type");
4184
4185           rhs = fold_convert (TREE_TYPE (memb), rhs);
4186           return build_constructor_single (type, memb, rhs);
4187         }
4188     }
4189
4190   /* Conversions among pointers */
4191   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4192            && (coder == codel))
4193     {
4194       tree ttl = TREE_TYPE (type);
4195       tree ttr = TREE_TYPE (rhstype);
4196       tree mvl = ttl;
4197       tree mvr = ttr;
4198       bool is_opaque_pointer;
4199       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4200
4201       if (TREE_CODE (mvl) != ARRAY_TYPE)
4202         mvl = TYPE_MAIN_VARIANT (mvl);
4203       if (TREE_CODE (mvr) != ARRAY_TYPE)
4204         mvr = TYPE_MAIN_VARIANT (mvr);
4205       /* Opaque pointers are treated like void pointers.  */
4206       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4207
4208       /* C++ does not allow the implicit conversion void* -> T*.  However,
4209          for the purpose of reducing the number of false positives, we
4210          tolerate the special case of
4211
4212                 int *p = NULL;
4213
4214          where NULL is typically defined in C to be '(void *) 0'.  */
4215       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4216         warning (OPT_Wc___compat, "request for implicit conversion from "
4217                  "%qT to %qT not permitted in C++", rhstype, type);
4218
4219       /* Check if the right-hand side has a format attribute but the
4220          left-hand side doesn't.  */
4221       if (warn_missing_format_attribute
4222           && check_missing_format_attribute (type, rhstype))
4223         {
4224           switch (errtype)
4225           {
4226           case ic_argpass:
4227           case ic_argpass_nonproto:
4228             warning (OPT_Wmissing_format_attribute,
4229                      "argument %d of %qE might be "
4230                      "a candidate for a format attribute",
4231                      parmnum, rname);
4232             break;
4233           case ic_assign:
4234             warning (OPT_Wmissing_format_attribute,
4235                      "assignment left-hand side might be "
4236                      "a candidate for a format attribute");
4237             break;
4238           case ic_init:
4239             warning (OPT_Wmissing_format_attribute,
4240                      "initialization left-hand side might be "
4241                      "a candidate for a format attribute");
4242             break;
4243           case ic_return:
4244             warning (OPT_Wmissing_format_attribute,
4245                      "return type might be "
4246                      "a candidate for a format attribute");
4247             break;
4248           default:
4249             gcc_unreachable ();
4250           }
4251         }
4252
4253       /* Any non-function converts to a [const][volatile] void *
4254          and vice versa; otherwise, targets must be the same.
4255          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4256       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4257           || (target_cmp = comp_target_types (type, rhstype))
4258           || is_opaque_pointer
4259           || (c_common_unsigned_type (mvl)
4260               == c_common_unsigned_type (mvr)))
4261         {
4262           if (pedantic
4263               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4264                   ||
4265                   (VOID_TYPE_P (ttr)
4266                    && !null_pointer_constant_p (rhs)
4267                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4268             WARN_FOR_ASSIGNMENT (input_location,
4269                                  G_("ISO C forbids passing argument %d of "
4270                                     "%qE between function pointer "
4271                                     "and %<void *%>"),
4272                                  G_("ISO C forbids assignment between "
4273                                     "function pointer and %<void *%>"),
4274                                  G_("ISO C forbids initialization between "
4275                                     "function pointer and %<void *%>"),
4276                                  G_("ISO C forbids return between function "
4277                                     "pointer and %<void *%>"));
4278           /* Const and volatile mean something different for function types,
4279              so the usual warnings are not appropriate.  */
4280           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4281                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4282             {
4283               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4284                 {
4285                   /* Types differing only by the presence of the 'volatile'
4286                      qualifier are acceptable if the 'volatile' has been added
4287                      in by the Objective-C EH machinery.  */
4288                   if (!objc_type_quals_match (ttl, ttr))
4289                     WARN_FOR_ASSIGNMENT (input_location,
4290                                          G_("passing argument %d of %qE discards "
4291                                             "qualifiers from pointer target type"),
4292                                          G_("assignment discards qualifiers "
4293                                             "from pointer target type"),
4294                                          G_("initialization discards qualifiers "
4295                                             "from pointer target type"),
4296                                          G_("return discards qualifiers from "
4297                                             "pointer target type"));
4298                 }
4299               /* If this is not a case of ignoring a mismatch in signedness,
4300                  no warning.  */
4301               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4302                        || target_cmp)
4303                 ;
4304               /* If there is a mismatch, do warn.  */
4305               else if (warn_pointer_sign)
4306                 WARN_FOR_ASSIGNMENT (input_location,
4307                                      G_("pointer targets in passing argument "
4308                                         "%d of %qE differ in signedness"),
4309                                      G_("pointer targets in assignment "
4310                                         "differ in signedness"),
4311                                      G_("pointer targets in initialization "
4312                                         "differ in signedness"),
4313                                      G_("pointer targets in return differ "
4314                                         "in signedness"));
4315             }
4316           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4317                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4318             {
4319               /* Because const and volatile on functions are restrictions
4320                  that say the function will not do certain things,
4321                  it is okay to use a const or volatile function
4322                  where an ordinary one is wanted, but not vice-versa.  */
4323               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4324                 WARN_FOR_ASSIGNMENT (input_location,
4325                                      G_("passing argument %d of %qE makes "
4326                                         "qualified function pointer "
4327                                         "from unqualified"),
4328                                      G_("assignment makes qualified function "
4329                                         "pointer from unqualified"),
4330                                      G_("initialization makes qualified "
4331                                         "function pointer from unqualified"),
4332                                      G_("return makes qualified function "
4333                                         "pointer from unqualified"));
4334             }
4335         }
4336       else
4337         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4338         if (!objc_ok)
4339           WARN_FOR_ASSIGNMENT (input_location,
4340                                G_("passing argument %d of %qE from "
4341                                   "incompatible pointer type"),
4342                                G_("assignment from incompatible pointer type"),
4343                                G_("initialization from incompatible "
4344                                   "pointer type"),
4345                                G_("return from incompatible pointer type"));
4346
4347       return convert (type, rhs);
4348     }
4349   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4350     {
4351       /* ??? This should not be an error when inlining calls to
4352          unprototyped functions.  */
4353       error ("invalid use of non-lvalue array");
4354       return error_mark_node;
4355     }
4356   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4357     {
4358       /* An explicit constant 0 can convert to a pointer,
4359          or one that results from arithmetic, even including
4360          a cast to integer type.  */
4361       if (!null_pointer_constant_p (rhs))
4362         WARN_FOR_ASSIGNMENT (input_location,
4363                              G_("passing argument %d of %qE makes "
4364                                 "pointer from integer without a cast"),
4365                              G_("assignment makes pointer from integer "
4366                                 "without a cast"),
4367                              G_("initialization makes pointer from "
4368                                 "integer without a cast"),
4369                              G_("return makes pointer from integer "
4370                                 "without a cast"));
4371
4372       return convert (type, rhs);
4373     }
4374   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4375     {
4376       WARN_FOR_ASSIGNMENT (input_location,
4377                            G_("passing argument %d of %qE makes integer "
4378                               "from pointer without a cast"),
4379                            G_("assignment makes integer from pointer "
4380                               "without a cast"),
4381                            G_("initialization makes integer from pointer "
4382                               "without a cast"),
4383                            G_("return makes integer from pointer "
4384                               "without a cast"));
4385       return convert (type, rhs);
4386     }
4387   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4388     return convert (type, rhs);
4389
4390   switch (errtype)
4391     {
4392     case ic_argpass:
4393     case ic_argpass_nonproto:
4394       /* ??? This should not be an error when inlining calls to
4395          unprototyped functions.  */
4396       error ("incompatible type for argument %d of %qE", parmnum, rname);
4397       break;
4398     case ic_assign:
4399       error ("incompatible types in assignment");
4400       break;
4401     case ic_init:
4402       error ("incompatible types in initialization");
4403       break;
4404     case ic_return:
4405       error ("incompatible types in return");
4406       break;
4407     default:
4408       gcc_unreachable ();
4409     }
4410
4411   return error_mark_node;
4412 }
4413 \f
4414 /* If VALUE is a compound expr all of whose expressions are constant, then
4415    return its value.  Otherwise, return error_mark_node.
4416
4417    This is for handling COMPOUND_EXPRs as initializer elements
4418    which is allowed with a warning when -pedantic is specified.  */
4419
4420 static tree
4421 valid_compound_expr_initializer (tree value, tree endtype)
4422 {
4423   if (TREE_CODE (value) == COMPOUND_EXPR)
4424     {
4425       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4426           == error_mark_node)
4427         return error_mark_node;
4428       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4429                                               endtype);
4430     }
4431   else if (!initializer_constant_valid_p (value, endtype))
4432     return error_mark_node;
4433   else
4434     return value;
4435 }
4436 \f
4437 /* Perform appropriate conversions on the initial value of a variable,
4438    store it in the declaration DECL,
4439    and print any error messages that are appropriate.
4440    If the init is invalid, store an ERROR_MARK.  */
4441
4442 void
4443 store_init_value (tree decl, tree init)
4444 {
4445   tree value, type;
4446
4447   /* If variable's type was invalidly declared, just ignore it.  */
4448
4449   type = TREE_TYPE (decl);
4450   if (TREE_CODE (type) == ERROR_MARK)
4451     return;
4452
4453   /* Digest the specified initializer into an expression.  */
4454
4455   value = digest_init (type, init, true, TREE_STATIC (decl));
4456
4457   /* Store the expression if valid; else report error.  */
4458
4459   if (!in_system_header
4460       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4461     warning (OPT_Wtraditional, "traditional C rejects automatic "
4462              "aggregate initialization");
4463
4464   DECL_INITIAL (decl) = value;
4465
4466   /* ANSI wants warnings about out-of-range constant initializers.  */
4467   STRIP_TYPE_NOPS (value);
4468   if (TREE_STATIC (decl))
4469     constant_expression_warning (value);
4470
4471   /* Check if we need to set array size from compound literal size.  */
4472   if (TREE_CODE (type) == ARRAY_TYPE
4473       && TYPE_DOMAIN (type) == 0
4474       && value != error_mark_node)
4475     {
4476       tree inside_init = init;
4477
4478       STRIP_TYPE_NOPS (inside_init);
4479       inside_init = fold (inside_init);
4480
4481       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4482         {
4483           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4484
4485           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4486             {
4487               /* For int foo[] = (int [3]){1}; we need to set array size
4488                  now since later on array initializer will be just the
4489                  brace enclosed list of the compound literal.  */
4490               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4491               TREE_TYPE (decl) = type;
4492               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4493               layout_type (type);
4494               layout_decl (cldecl, 0);
4495             }
4496         }
4497     }
4498 }
4499 \f
4500 /* Methods for storing and printing names for error messages.  */
4501
4502 /* Implement a spelling stack that allows components of a name to be pushed
4503    and popped.  Each element on the stack is this structure.  */
4504
4505 struct spelling
4506 {
4507   int kind;
4508   union
4509     {
4510       unsigned HOST_WIDE_INT i;
4511       const char *s;
4512     } u;
4513 };
4514
4515 #define SPELLING_STRING 1
4516 #define SPELLING_MEMBER 2
4517 #define SPELLING_BOUNDS 3
4518
4519 static struct spelling *spelling;       /* Next stack element (unused).  */
4520 static struct spelling *spelling_base;  /* Spelling stack base.  */
4521 static int spelling_size;               /* Size of the spelling stack.  */
4522
4523 /* Macros to save and restore the spelling stack around push_... functions.
4524    Alternative to SAVE_SPELLING_STACK.  */
4525
4526 #define SPELLING_DEPTH() (spelling - spelling_base)
4527 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4528
4529 /* Push an element on the spelling stack with type KIND and assign VALUE
4530    to MEMBER.  */
4531
4532 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4533 {                                                                       \
4534   int depth = SPELLING_DEPTH ();                                        \
4535                                                                         \
4536   if (depth >= spelling_size)                                           \
4537     {                                                                   \
4538       spelling_size += 10;                                              \
4539       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4540                                   spelling_size);                       \
4541       RESTORE_SPELLING_DEPTH (depth);                                   \
4542     }                                                                   \
4543                                                                         \
4544   spelling->kind = (KIND);                                              \
4545   spelling->MEMBER = (VALUE);                                           \
4546   spelling++;                                                           \
4547 }
4548
4549 /* Push STRING on the stack.  Printed literally.  */
4550
4551 static void
4552 push_string (const char *string)
4553 {
4554   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4555 }
4556
4557 /* Push a member name on the stack.  Printed as '.' STRING.  */
4558
4559 static void
4560 push_member_name (tree decl)
4561 {
4562   const char *const string
4563     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4564   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4565 }
4566
4567 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4568
4569 static void
4570 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4571 {
4572   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4573 }
4574
4575 /* Compute the maximum size in bytes of the printed spelling.  */
4576
4577 static int
4578 spelling_length (void)
4579 {
4580   int size = 0;
4581   struct spelling *p;
4582
4583   for (p = spelling_base; p < spelling; p++)
4584     {
4585       if (p->kind == SPELLING_BOUNDS)
4586         size += 25;
4587       else
4588         size += strlen (p->u.s) + 1;
4589     }
4590
4591   return size;
4592 }
4593
4594 /* Print the spelling to BUFFER and return it.  */
4595
4596 static char *
4597 print_spelling (char *buffer)
4598 {
4599   char *d = buffer;
4600   struct spelling *p;
4601
4602   for (p = spelling_base; p < spelling; p++)
4603     if (p->kind == SPELLING_BOUNDS)
4604       {
4605         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4606         d += strlen (d);
4607       }
4608     else
4609       {
4610         const char *s;
4611         if (p->kind == SPELLING_MEMBER)
4612           *d++ = '.';
4613         for (s = p->u.s; (*d = *s++); d++)
4614           ;
4615       }
4616   *d++ = '\0';
4617   return buffer;
4618 }
4619
4620 /* Issue an error message for a bad initializer component.
4621    MSGID identifies the message.
4622    The component name is taken from the spelling stack.  */
4623
4624 void
4625 error_init (const char *msgid)
4626 {
4627   char *ofwhat;
4628
4629   error ("%s", _(msgid));
4630   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4631   if (*ofwhat)
4632     error ("(near initialization for %qs)", ofwhat);
4633 }
4634
4635 /* Issue a pedantic warning for a bad initializer component.  OPT is
4636    the option OPT_* (from options.h) controlling this warning or 0 if
4637    it is unconditionally given.  MSGID identifies the message.  The
4638    component name is taken from the spelling stack.  */
4639
4640 void
4641 pedwarn_init (location_t location, int opt, const char *msgid)
4642 {
4643   char *ofwhat;
4644
4645   pedwarn (location, opt, "%s", _(msgid));
4646   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4647   if (*ofwhat)
4648     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
4649 }
4650
4651 /* Issue a warning for a bad initializer component.
4652
4653    OPT is the OPT_W* value corresponding to the warning option that
4654    controls this warning.  MSGID identifies the message.  The
4655    component name is taken from the spelling stack.  */
4656
4657 static void
4658 warning_init (int opt, const char *msgid)
4659 {
4660   char *ofwhat;
4661
4662   warning (opt, "%s", _(msgid));
4663   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4664   if (*ofwhat)
4665     warning (opt, "(near initialization for %qs)", ofwhat);
4666 }
4667 \f
4668 /* If TYPE is an array type and EXPR is a parenthesized string
4669    constant, warn if pedantic that EXPR is being used to initialize an
4670    object of type TYPE.  */
4671
4672 void
4673 maybe_warn_string_init (tree type, struct c_expr expr)
4674 {
4675   if (pedantic
4676       && TREE_CODE (type) == ARRAY_TYPE
4677       && TREE_CODE (expr.value) == STRING_CST
4678       && expr.original_code != STRING_CST)
4679     pedwarn_init (input_location, OPT_pedantic,
4680                   "array initialized from parenthesized string constant");
4681 }
4682
4683 /* Digest the parser output INIT as an initializer for type TYPE.
4684    Return a C expression of type TYPE to represent the initial value.
4685
4686    If INIT is a string constant, STRICT_STRING is true if it is
4687    unparenthesized or we should not warn here for it being parenthesized.
4688    For other types of INIT, STRICT_STRING is not used.
4689
4690    REQUIRE_CONSTANT requests an error if non-constant initializers or
4691    elements are seen.  */
4692
4693 static tree
4694 digest_init (tree type, tree init, bool strict_string, int require_constant)
4695 {
4696   enum tree_code code = TREE_CODE (type);
4697   tree inside_init = init;
4698
4699   if (type == error_mark_node
4700       || !init
4701       || init == error_mark_node
4702       || TREE_TYPE (init) == error_mark_node)
4703     return error_mark_node;
4704
4705   STRIP_TYPE_NOPS (inside_init);
4706
4707   inside_init = fold (inside_init);
4708
4709   /* Initialization of an array of chars from a string constant
4710      optionally enclosed in braces.  */
4711
4712   if (code == ARRAY_TYPE && inside_init
4713       && TREE_CODE (inside_init) == STRING_CST)
4714     {
4715       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4716       /* Note that an array could be both an array of character type
4717          and an array of wchar_t if wchar_t is signed char or unsigned
4718          char.  */
4719       bool char_array = (typ1 == char_type_node
4720                          || typ1 == signed_char_type_node
4721                          || typ1 == unsigned_char_type_node);
4722       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4723       bool char16_array = !!comptypes (typ1, char16_type_node);
4724       bool char32_array = !!comptypes (typ1, char32_type_node);
4725
4726       if (char_array || wchar_array || char16_array || char32_array)
4727         {
4728           struct c_expr expr;
4729           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
4730           expr.value = inside_init;
4731           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4732           maybe_warn_string_init (type, expr);
4733
4734           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4735                          TYPE_MAIN_VARIANT (type)))
4736             return inside_init;
4737
4738           if (char_array)
4739             {
4740               if (typ2 != char_type_node)
4741                 {
4742                   error_init ("char-array initialized from wide string");
4743                   return error_mark_node;
4744                 }
4745             }
4746           else
4747             {
4748               if (typ2 == char_type_node)
4749                 {
4750                   error_init ("wide character array initialized from non-wide "
4751                               "string");
4752                   return error_mark_node;
4753                 }
4754               else if (!comptypes(typ1, typ2))
4755                 {
4756                   error_init ("wide character array initialized from "
4757                               "incompatible wide string");
4758                   return error_mark_node;
4759                 }
4760             }
4761
4762           TREE_TYPE (inside_init) = type;
4763           if (TYPE_DOMAIN (type) != 0
4764               && TYPE_SIZE (type) != 0
4765               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4766               /* Subtract the size of a single (possibly wide) character
4767                  because it's ok to ignore the terminating null char
4768                  that is counted in the length of the constant.  */
4769               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4770                                        TREE_STRING_LENGTH (inside_init)
4771                                        - (TYPE_PRECISION (typ1)
4772                                           / BITS_PER_UNIT)))
4773             pedwarn_init (input_location, 0,
4774                           "initializer-string for array of chars is too long");
4775
4776           return inside_init;
4777         }
4778       else if (INTEGRAL_TYPE_P (typ1))
4779         {
4780           error_init ("array of inappropriate type initialized "
4781                       "from string constant");
4782           return error_mark_node;
4783         }
4784     }
4785
4786   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4787      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4788      below and handle as a constructor.  */
4789   if (code == VECTOR_TYPE
4790       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4791       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4792       && TREE_CONSTANT (inside_init))
4793     {
4794       if (TREE_CODE (inside_init) == VECTOR_CST
4795           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4796                         TYPE_MAIN_VARIANT (type)))
4797         return inside_init;
4798
4799       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4800         {
4801           unsigned HOST_WIDE_INT ix;
4802           tree value;
4803           bool constant_p = true;
4804
4805           /* Iterate through elements and check if all constructor
4806              elements are *_CSTs.  */
4807           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4808             if (!CONSTANT_CLASS_P (value))
4809               {
4810                 constant_p = false;
4811                 break;
4812               }
4813
4814           if (constant_p)
4815             return build_vector_from_ctor (type,
4816                                            CONSTRUCTOR_ELTS (inside_init));
4817         }
4818     }
4819
4820   if (warn_sequence_point)
4821     verify_sequence_points (inside_init);
4822
4823   /* Any type can be initialized
4824      from an expression of the same type, optionally with braces.  */
4825
4826   if (inside_init && TREE_TYPE (inside_init) != 0
4827       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4828                      TYPE_MAIN_VARIANT (type))
4829           || (code == ARRAY_TYPE
4830               && comptypes (TREE_TYPE (inside_init), type))
4831           || (code == VECTOR_TYPE
4832               && comptypes (TREE_TYPE (inside_init), type))
4833           || (code == POINTER_TYPE
4834               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4835               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4836                             TREE_TYPE (type)))))
4837     {
4838       if (code == POINTER_TYPE)
4839         {
4840           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4841             {
4842               if (TREE_CODE (inside_init) == STRING_CST
4843                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4844                 inside_init = array_to_pointer_conversion (inside_init);
4845               else
4846                 {
4847                   error_init ("invalid use of non-lvalue array");
4848                   return error_mark_node;
4849                 }
4850             }
4851         }
4852
4853       if (code == VECTOR_TYPE)
4854         /* Although the types are compatible, we may require a
4855            conversion.  */
4856         inside_init = convert (type, inside_init);
4857
4858       if (require_constant
4859           && (code == VECTOR_TYPE || !flag_isoc99)
4860           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4861         {
4862           /* As an extension, allow initializing objects with static storage
4863              duration with compound literals (which are then treated just as
4864              the brace enclosed list they contain).  Also allow this for
4865              vectors, as we can only assign them with compound literals.  */
4866           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4867           inside_init = DECL_INITIAL (decl);
4868         }
4869
4870       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4871           && TREE_CODE (inside_init) != CONSTRUCTOR)
4872         {
4873           error_init ("array initialized from non-constant array expression");
4874           return error_mark_node;
4875         }
4876
4877       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4878         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4879
4880       /* Compound expressions can only occur here if -pedantic or
4881          -pedantic-errors is specified.  In the later case, we always want
4882          an error.  In the former case, we simply want a warning.  */
4883       if (require_constant && pedantic
4884           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4885         {
4886           inside_init
4887             = valid_compound_expr_initializer (inside_init,
4888                                                TREE_TYPE (inside_init));
4889           if (inside_init == error_mark_node)
4890             error_init ("initializer element is not constant");
4891           else
4892             pedwarn_init (input_location, OPT_pedantic,
4893                           "initializer element is not constant");
4894           if (flag_pedantic_errors)
4895             inside_init = error_mark_node;
4896         }
4897       else if (require_constant
4898                && !initializer_constant_valid_p (inside_init,
4899                                                  TREE_TYPE (inside_init)))
4900         {
4901           error_init ("initializer element is not constant");
4902           inside_init = error_mark_node;
4903         }
4904
4905       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4906       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4907         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4908                                               NULL_TREE, 0);
4909       return inside_init;
4910     }
4911
4912   /* Handle scalar types, including conversions.  */
4913
4914   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4915       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4916       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4917     {
4918       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4919           && (TREE_CODE (init) == STRING_CST
4920               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4921         init = array_to_pointer_conversion (init);
4922       inside_init
4923         = convert_for_assignment (type, init, ic_init,
4924                                   NULL_TREE, NULL_TREE, 0);
4925
4926       /* Check to see if we have already given an error message.  */
4927       if (inside_init == error_mark_node)
4928         ;
4929       else if (require_constant && !TREE_CONSTANT (inside_init))
4930         {
4931           error_init ("initializer element is not constant");
4932           inside_init = error_mark_node;
4933         }
4934       else if (require_constant
4935                && !initializer_constant_valid_p (inside_init,
4936                                                  TREE_TYPE (inside_init)))
4937         {
4938           error_init ("initializer element is not computable at load time");
4939           inside_init = error_mark_node;
4940         }
4941
4942       return inside_init;
4943     }
4944
4945   /* Come here only for records and arrays.  */
4946
4947   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4948     {
4949       error_init ("variable-sized object may not be initialized");
4950       return error_mark_node;
4951     }
4952
4953   error_init ("invalid initializer");
4954   return error_mark_node;
4955 }
4956 \f
4957 /* Handle initializers that use braces.  */
4958
4959 /* Type of object we are accumulating a constructor for.
4960    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4961 static tree constructor_type;
4962
4963 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4964    left to fill.  */
4965 static tree constructor_fields;
4966
4967 /* For an ARRAY_TYPE, this is the specified index
4968    at which to store the next element we get.  */
4969 static tree constructor_index;
4970
4971 /* For an ARRAY_TYPE, this is the maximum index.  */
4972 static tree constructor_max_index;
4973
4974 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4975 static tree constructor_unfilled_fields;
4976
4977 /* For an ARRAY_TYPE, this is the index of the first element
4978    not yet written out.  */
4979 static tree constructor_unfilled_index;
4980
4981 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4982    This is so we can generate gaps between fields, when appropriate.  */
4983 static tree constructor_bit_index;
4984
4985 /* If we are saving up the elements rather than allocating them,
4986    this is the list of elements so far (in reverse order,
4987    most recent first).  */
4988 static VEC(constructor_elt,gc) *constructor_elements;
4989
4990 /* 1 if constructor should be incrementally stored into a constructor chain,
4991    0 if all the elements should be kept in AVL tree.  */
4992 static int constructor_incremental;
4993
4994 /* 1 if so far this constructor's elements are all compile-time constants.  */
4995 static int constructor_constant;
4996
4997 /* 1 if so far this constructor's elements are all valid address constants.  */
4998 static int constructor_simple;
4999
5000 /* 1 if this constructor is erroneous so far.  */
5001 static int constructor_erroneous;
5002
5003 /* Structure for managing pending initializer elements, organized as an
5004    AVL tree.  */
5005
5006 struct init_node
5007 {
5008   struct init_node *left, *right;
5009   struct init_node *parent;
5010   int balance;
5011   tree purpose;
5012   tree value;
5013 };
5014
5015 /* Tree of pending elements at this constructor level.
5016    These are elements encountered out of order
5017    which belong at places we haven't reached yet in actually
5018    writing the output.
5019    Will never hold tree nodes across GC runs.  */
5020 static struct init_node *constructor_pending_elts;
5021
5022 /* The SPELLING_DEPTH of this constructor.  */
5023 static int constructor_depth;
5024
5025 /* DECL node for which an initializer is being read.
5026    0 means we are reading a constructor expression
5027    such as (struct foo) {...}.  */
5028 static tree constructor_decl;
5029
5030 /* Nonzero if this is an initializer for a top-level decl.  */
5031 static int constructor_top_level;
5032
5033 /* Nonzero if there were any member designators in this initializer.  */
5034 static int constructor_designated;
5035
5036 /* Nesting depth of designator list.  */
5037 static int designator_depth;
5038
5039 /* Nonzero if there were diagnosed errors in this designator list.  */
5040 static int designator_erroneous;
5041
5042 \f
5043 /* This stack has a level for each implicit or explicit level of
5044    structuring in the initializer, including the outermost one.  It
5045    saves the values of most of the variables above.  */
5046
5047 struct constructor_range_stack;
5048
5049 struct constructor_stack
5050 {
5051   struct constructor_stack *next;
5052   tree type;
5053   tree fields;
5054   tree index;
5055   tree max_index;
5056   tree unfilled_index;
5057   tree unfilled_fields;
5058   tree bit_index;
5059   VEC(constructor_elt,gc) *elements;
5060   struct init_node *pending_elts;
5061   int offset;
5062   int depth;
5063   /* If value nonzero, this value should replace the entire
5064      constructor at this level.  */
5065   struct c_expr replacement_value;
5066   struct constructor_range_stack *range_stack;
5067   char constant;
5068   char simple;
5069   char implicit;
5070   char erroneous;
5071   char outer;
5072   char incremental;
5073   char designated;
5074 };
5075
5076 static struct constructor_stack *constructor_stack;
5077
5078 /* This stack represents designators from some range designator up to
5079    the last designator in the list.  */
5080
5081 struct constructor_range_stack
5082 {
5083   struct constructor_range_stack *next, *prev;
5084   struct constructor_stack *stack;
5085   tree range_start;
5086   tree index;
5087   tree range_end;
5088   tree fields;
5089 };
5090
5091 static struct constructor_range_stack *constructor_range_stack;
5092
5093 /* This stack records separate initializers that are nested.
5094    Nested initializers can't happen in ANSI C, but GNU C allows them
5095    in cases like { ... (struct foo) { ... } ... }.  */
5096
5097 struct initializer_stack
5098 {
5099   struct initializer_stack *next;
5100   tree decl;
5101   struct constructor_stack *constructor_stack;
5102   struct constructor_range_stack *constructor_range_stack;
5103   VEC(constructor_elt,gc) *elements;
5104   struct spelling *spelling;
5105   struct spelling *spelling_base;
5106   int spelling_size;
5107   char top_level;
5108   char require_constant_value;
5109   char require_constant_elements;
5110 };
5111
5112 static struct initializer_stack *initializer_stack;
5113 \f
5114 /* Prepare to parse and output the initializer for variable DECL.  */
5115
5116 void
5117 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5118 {
5119   const char *locus;
5120   struct initializer_stack *p = XNEW (struct initializer_stack);
5121
5122   p->decl = constructor_decl;
5123   p->require_constant_value = require_constant_value;
5124   p->require_constant_elements = require_constant_elements;
5125   p->constructor_stack = constructor_stack;
5126   p->constructor_range_stack = constructor_range_stack;
5127   p->elements = constructor_elements;
5128   p->spelling = spelling;
5129   p->spelling_base = spelling_base;
5130   p->spelling_size = spelling_size;
5131   p->top_level = constructor_top_level;
5132   p->next = initializer_stack;
5133   initializer_stack = p;
5134
5135   constructor_decl = decl;
5136   constructor_designated = 0;
5137   constructor_top_level = top_level;
5138
5139   if (decl != 0 && decl != error_mark_node)
5140     {
5141       require_constant_value = TREE_STATIC (decl);
5142       require_constant_elements
5143         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5144            /* For a scalar, you can always use any value to initialize,
5145               even within braces.  */
5146            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5147                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5148                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5149                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5150       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5151     }
5152   else
5153     {
5154       require_constant_value = 0;
5155       require_constant_elements = 0;
5156       locus = "(anonymous)";
5157     }
5158
5159   constructor_stack = 0;
5160   constructor_range_stack = 0;
5161
5162   missing_braces_mentioned = 0;
5163
5164   spelling_base = 0;
5165   spelling_size = 0;
5166   RESTORE_SPELLING_DEPTH (0);
5167
5168   if (locus)
5169     push_string (locus);
5170 }
5171
5172 void
5173 finish_init (void)
5174 {
5175   struct initializer_stack *p = initializer_stack;
5176
5177   /* Free the whole constructor stack of this initializer.  */
5178   while (constructor_stack)
5179     {
5180       struct constructor_stack *q = constructor_stack;
5181       constructor_stack = q->next;
5182       free (q);
5183     }
5184
5185   gcc_assert (!constructor_range_stack);
5186
5187   /* Pop back to the data of the outer initializer (if any).  */
5188   free (spelling_base);
5189
5190   constructor_decl = p->decl;
5191   require_constant_value = p->require_constant_value;
5192   require_constant_elements = p->require_constant_elements;
5193   constructor_stack = p->constructor_stack;
5194   constructor_range_stack = p->constructor_range_stack;
5195   constructor_elements = p->elements;
5196   spelling = p->spelling;
5197   spelling_base = p->spelling_base;
5198   spelling_size = p->spelling_size;
5199   constructor_top_level = p->top_level;
5200   initializer_stack = p->next;
5201   free (p);
5202 }
5203 \f
5204 /* Call here when we see the initializer is surrounded by braces.
5205    This is instead of a call to push_init_level;
5206    it is matched by a call to pop_init_level.
5207
5208    TYPE is the type to initialize, for a constructor expression.
5209    For an initializer for a decl, TYPE is zero.  */
5210
5211 void
5212 really_start_incremental_init (tree type)
5213 {
5214   struct constructor_stack *p = XNEW (struct constructor_stack);
5215
5216   if (type == 0)
5217     type = TREE_TYPE (constructor_decl);
5218
5219   if (targetm.vector_opaque_p (type))
5220     error ("opaque vector types cannot be initialized");
5221
5222   p->type = constructor_type;
5223   p->fields = constructor_fields;
5224   p->index = constructor_index;
5225   p->max_index = constructor_max_index;
5226   p->unfilled_index = constructor_unfilled_index;
5227   p->unfilled_fields = constructor_unfilled_fields;
5228   p->bit_index = constructor_bit_index;
5229   p->elements = constructor_elements;
5230   p->constant = constructor_constant;
5231   p->simple = constructor_simple;
5232   p->erroneous = constructor_erroneous;
5233   p->pending_elts = constructor_pending_elts;
5234   p->depth = constructor_depth;
5235   p->replacement_value.value = 0;
5236   p->replacement_value.original_code = ERROR_MARK;
5237   p->implicit = 0;
5238   p->range_stack = 0;
5239   p->outer = 0;
5240   p->incremental = constructor_incremental;
5241   p->designated = constructor_designated;
5242   p->next = 0;
5243   constructor_stack = p;
5244
5245   constructor_constant = 1;
5246   constructor_simple = 1;
5247   constructor_depth = SPELLING_DEPTH ();
5248   constructor_elements = 0;
5249   constructor_pending_elts = 0;
5250   constructor_type = type;
5251   constructor_incremental = 1;
5252   constructor_designated = 0;
5253   designator_depth = 0;
5254   designator_erroneous = 0;
5255
5256   if (TREE_CODE (constructor_type) == RECORD_TYPE
5257       || TREE_CODE (constructor_type) == UNION_TYPE)
5258     {
5259       constructor_fields = TYPE_FIELDS (constructor_type);
5260       /* Skip any nameless bit fields at the beginning.  */
5261       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5262              && DECL_NAME (constructor_fields) == 0)
5263         constructor_fields = TREE_CHAIN (constructor_fields);
5264
5265       constructor_unfilled_fields = constructor_fields;
5266       constructor_bit_index = bitsize_zero_node;
5267     }
5268   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5269     {
5270       if (TYPE_DOMAIN (constructor_type))
5271         {
5272           constructor_max_index
5273             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5274
5275           /* Detect non-empty initializations of zero-length arrays.  */
5276           if (constructor_max_index == NULL_TREE
5277               && TYPE_SIZE (constructor_type))
5278             constructor_max_index = build_int_cst (NULL_TREE, -1);
5279
5280           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5281              to initialize VLAs will cause a proper error; avoid tree
5282              checking errors as well by setting a safe value.  */
5283           if (constructor_max_index
5284               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5285             constructor_max_index = build_int_cst (NULL_TREE, -1);
5286
5287           constructor_index
5288             = convert (bitsizetype,
5289                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5290         }
5291       else
5292         {
5293           constructor_index = bitsize_zero_node;
5294           constructor_max_index = NULL_TREE;
5295         }
5296
5297       constructor_unfilled_index = constructor_index;
5298     }
5299   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5300     {
5301       /* Vectors are like simple fixed-size arrays.  */
5302       constructor_max_index =
5303         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5304       constructor_index = bitsize_zero_node;
5305       constructor_unfilled_index = constructor_index;
5306     }
5307   else
5308     {
5309       /* Handle the case of int x = {5}; */
5310       constructor_fields = constructor_type;
5311       constructor_unfilled_fields = constructor_type;
5312     }
5313 }
5314 \f
5315 /* Push down into a subobject, for initialization.
5316    If this is for an explicit set of braces, IMPLICIT is 0.
5317    If it is because the next element belongs at a lower level,
5318    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5319
5320 void
5321 push_init_level (int implicit)
5322 {
5323   struct constructor_stack *p;
5324   tree value = NULL_TREE;
5325
5326   /* If we've exhausted any levels that didn't have braces,
5327      pop them now.  If implicit == 1, this will have been done in
5328      process_init_element; do not repeat it here because in the case
5329      of excess initializers for an empty aggregate this leads to an
5330      infinite cycle of popping a level and immediately recreating
5331      it.  */
5332   if (implicit != 1)
5333     {
5334       while (constructor_stack->implicit)
5335         {
5336           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5337                || TREE_CODE (constructor_type) == UNION_TYPE)
5338               && constructor_fields == 0)
5339             process_init_element (pop_init_level (1));
5340           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5341                    && constructor_max_index
5342                    && tree_int_cst_lt (constructor_max_index,
5343                                        constructor_index))
5344             process_init_element (pop_init_level (1));
5345           else
5346             break;
5347         }
5348     }
5349
5350   /* Unless this is an explicit brace, we need to preserve previous
5351      content if any.  */
5352   if (implicit)
5353     {
5354       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5355            || TREE_CODE (constructor_type) == UNION_TYPE)
5356           && constructor_fields)
5357         value = find_init_member (constructor_fields);
5358       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5359         value = find_init_member (constructor_index);
5360     }
5361
5362   p = XNEW (struct constructor_stack);
5363   p->type = constructor_type;
5364   p->fields = constructor_fields;
5365   p->index = constructor_index;
5366   p->max_index = constructor_max_index;
5367   p->unfilled_index = constructor_unfilled_index;
5368   p->unfilled_fields = constructor_unfilled_fields;
5369   p->bit_index = constructor_bit_index;
5370   p->elements = constructor_elements;
5371   p->constant = constructor_constant;
5372   p->simple = constructor_simple;
5373   p->erroneous = constructor_erroneous;
5374   p->pending_elts = constructor_pending_elts;
5375   p->depth = constructor_depth;
5376   p->replacement_value.value = 0;
5377   p->replacement_value.original_code = ERROR_MARK;
5378   p->implicit = implicit;
5379   p->outer = 0;
5380   p->incremental = constructor_incremental;
5381   p->designated = constructor_designated;
5382   p->next = constructor_stack;
5383   p->range_stack = 0;
5384   constructor_stack = p;
5385
5386   constructor_constant = 1;
5387   constructor_simple = 1;
5388   constructor_depth = SPELLING_DEPTH ();
5389   constructor_elements = 0;
5390   constructor_incremental = 1;
5391   constructor_designated = 0;
5392   constructor_pending_elts = 0;
5393   if (!implicit)
5394     {
5395       p->range_stack = constructor_range_stack;
5396       constructor_range_stack = 0;
5397       designator_depth = 0;
5398       designator_erroneous = 0;
5399     }
5400
5401   /* Don't die if an entire brace-pair level is superfluous
5402      in the containing level.  */
5403   if (constructor_type == 0)
5404     ;
5405   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5406            || TREE_CODE (constructor_type) == UNION_TYPE)
5407     {
5408       /* Don't die if there are extra init elts at the end.  */
5409       if (constructor_fields == 0)
5410         constructor_type = 0;
5411       else
5412         {
5413           constructor_type = TREE_TYPE (constructor_fields);
5414           push_member_name (constructor_fields);
5415           constructor_depth++;
5416         }
5417     }
5418   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5419     {
5420       constructor_type = TREE_TYPE (constructor_type);
5421       push_array_bounds (tree_low_cst (constructor_index, 1));
5422       constructor_depth++;
5423     }
5424
5425   if (constructor_type == 0)
5426     {
5427       error_init ("extra brace group at end of initializer");
5428       constructor_fields = 0;
5429       constructor_unfilled_fields = 0;
5430       return;
5431     }
5432
5433   if (value && TREE_CODE (value) == CONSTRUCTOR)
5434     {
5435       constructor_constant = TREE_CONSTANT (value);
5436       constructor_simple = TREE_STATIC (value);
5437       constructor_elements = CONSTRUCTOR_ELTS (value);
5438       if (!VEC_empty (constructor_elt, constructor_elements)
5439           && (TREE_CODE (constructor_type) == RECORD_TYPE
5440               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5441         set_nonincremental_init ();
5442     }
5443
5444   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5445     {
5446       missing_braces_mentioned = 1;
5447       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5448     }
5449
5450   if (TREE_CODE (constructor_type) == RECORD_TYPE
5451            || TREE_CODE (constructor_type) == UNION_TYPE)
5452     {
5453       constructor_fields = TYPE_FIELDS (constructor_type);
5454       /* Skip any nameless bit fields at the beginning.  */
5455       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5456              && DECL_NAME (constructor_fields) == 0)
5457         constructor_fields = TREE_CHAIN (constructor_fields);
5458
5459       constructor_unfilled_fields = constructor_fields;
5460       constructor_bit_index = bitsize_zero_node;
5461     }
5462   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5463     {
5464       /* Vectors are like simple fixed-size arrays.  */
5465       constructor_max_index =
5466         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5467       constructor_index = convert (bitsizetype, integer_zero_node);
5468       constructor_unfilled_index = constructor_index;
5469     }
5470   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5471     {
5472       if (TYPE_DOMAIN (constructor_type))
5473         {
5474           constructor_max_index
5475             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5476
5477           /* Detect non-empty initializations of zero-length arrays.  */
5478           if (constructor_max_index == NULL_TREE
5479               && TYPE_SIZE (constructor_type))
5480             constructor_max_index = build_int_cst (NULL_TREE, -1);
5481
5482           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5483              to initialize VLAs will cause a proper error; avoid tree
5484              checking errors as well by setting a safe value.  */
5485           if (constructor_max_index
5486               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5487             constructor_max_index = build_int_cst (NULL_TREE, -1);
5488
5489           constructor_index
5490             = convert (bitsizetype,
5491                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5492         }
5493       else
5494         constructor_index = bitsize_zero_node;
5495
5496       constructor_unfilled_index = constructor_index;
5497       if (value && TREE_CODE (value) == STRING_CST)
5498         {
5499           /* We need to split the char/wchar array into individual
5500              characters, so that we don't have to special case it
5501              everywhere.  */
5502           set_nonincremental_init_from_string (value);
5503         }
5504     }
5505   else
5506     {
5507       if (constructor_type != error_mark_node)
5508         warning_init (0, "braces around scalar initializer");
5509       constructor_fields = constructor_type;
5510       constructor_unfilled_fields = constructor_type;
5511     }
5512 }
5513
5514 /* At the end of an implicit or explicit brace level,
5515    finish up that level of constructor.  If a single expression
5516    with redundant braces initialized that level, return the
5517    c_expr structure for that expression.  Otherwise, the original_code
5518    element is set to ERROR_MARK.
5519    If we were outputting the elements as they are read, return 0 as the value
5520    from inner levels (process_init_element ignores that),
5521    but return error_mark_node as the value from the outermost level
5522    (that's what we want to put in DECL_INITIAL).
5523    Otherwise, return a CONSTRUCTOR expression as the value.  */
5524
5525 struct c_expr
5526 pop_init_level (int implicit)
5527 {
5528   struct constructor_stack *p;
5529   struct c_expr ret;
5530   ret.value = 0;
5531   ret.original_code = ERROR_MARK;
5532
5533   if (implicit == 0)
5534     {
5535       /* When we come to an explicit close brace,
5536          pop any inner levels that didn't have explicit braces.  */
5537       while (constructor_stack->implicit)
5538         process_init_element (pop_init_level (1));
5539
5540       gcc_assert (!constructor_range_stack);
5541     }
5542
5543   /* Now output all pending elements.  */
5544   constructor_incremental = 1;
5545   output_pending_init_elements (1);
5546
5547   p = constructor_stack;
5548
5549   /* Error for initializing a flexible array member, or a zero-length
5550      array member in an inappropriate context.  */
5551   if (constructor_type && constructor_fields
5552       && TREE_CODE (constructor_type) == ARRAY_TYPE
5553       && TYPE_DOMAIN (constructor_type)
5554       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5555     {
5556       /* Silently discard empty initializations.  The parser will
5557          already have pedwarned for empty brackets.  */
5558       if (integer_zerop (constructor_unfilled_index))
5559         constructor_type = NULL_TREE;
5560       else
5561         {
5562           gcc_assert (!TYPE_SIZE (constructor_type));
5563
5564           if (constructor_depth > 2)
5565             error_init ("initialization of flexible array member in a nested context");
5566           else
5567             pedwarn_init (input_location, OPT_pedantic,
5568                           "initialization of a flexible array member");
5569
5570           /* We have already issued an error message for the existence
5571              of a flexible array member not at the end of the structure.
5572              Discard the initializer so that we do not die later.  */
5573           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5574             constructor_type = NULL_TREE;
5575         }
5576     }
5577
5578   /* Warn when some struct elements are implicitly initialized to zero.  */
5579   if (warn_missing_field_initializers
5580       && constructor_type
5581       && TREE_CODE (constructor_type) == RECORD_TYPE
5582       && constructor_unfilled_fields)
5583     {
5584         /* Do not warn for flexible array members or zero-length arrays.  */
5585         while (constructor_unfilled_fields
5586                && (!DECL_SIZE (constructor_unfilled_fields)
5587                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5588           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5589
5590         /* Do not warn if this level of the initializer uses member
5591            designators; it is likely to be deliberate.  */
5592         if (constructor_unfilled_fields && !constructor_designated)
5593           {
5594             push_member_name (constructor_unfilled_fields);
5595             warning_init (OPT_Wmissing_field_initializers,
5596                           "missing initializer");
5597             RESTORE_SPELLING_DEPTH (constructor_depth);
5598           }
5599     }
5600
5601   /* Pad out the end of the structure.  */
5602   if (p->replacement_value.value)
5603     /* If this closes a superfluous brace pair,
5604        just pass out the element between them.  */
5605     ret = p->replacement_value;
5606   else if (constructor_type == 0)
5607     ;
5608   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5609            && TREE_CODE (constructor_type) != UNION_TYPE
5610            && TREE_CODE (constructor_type) != ARRAY_TYPE
5611            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5612     {
5613       /* A nonincremental scalar initializer--just return
5614          the element, after verifying there is just one.  */
5615       if (VEC_empty (constructor_elt,constructor_elements))
5616         {
5617           if (!constructor_erroneous)
5618             error_init ("empty scalar initializer");
5619           ret.value = error_mark_node;
5620         }
5621       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5622         {
5623           error_init ("extra elements in scalar initializer");
5624           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5625         }
5626       else
5627         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5628     }
5629   else
5630     {
5631       if (constructor_erroneous)
5632         ret.value = error_mark_node;
5633       else
5634         {
5635           ret.value = build_constructor (constructor_type,
5636                                          constructor_elements);
5637           if (constructor_constant)
5638             TREE_CONSTANT (ret.value) = 1;
5639           if (constructor_constant && constructor_simple)
5640             TREE_STATIC (ret.value) = 1;
5641         }
5642     }
5643
5644   constructor_type = p->type;
5645   constructor_fields = p->fields;
5646   constructor_index = p->index;
5647   constructor_max_index = p->max_index;
5648   constructor_unfilled_index = p->unfilled_index;
5649   constructor_unfilled_fields = p->unfilled_fields;
5650   constructor_bit_index = p->bit_index;
5651   constructor_elements = p->elements;
5652   constructor_constant = p->constant;
5653   constructor_simple = p->simple;
5654   constructor_erroneous = p->erroneous;
5655   constructor_incremental = p->incremental;
5656   constructor_designated = p->designated;
5657   constructor_pending_elts = p->pending_elts;
5658   constructor_depth = p->depth;
5659   if (!p->implicit)
5660     constructor_range_stack = p->range_stack;
5661   RESTORE_SPELLING_DEPTH (constructor_depth);
5662
5663   constructor_stack = p->next;
5664   free (p);
5665
5666   if (ret.value == 0 && constructor_stack == 0)
5667     ret.value = error_mark_node;
5668   return ret;
5669 }
5670
5671 /* Common handling for both array range and field name designators.
5672    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5673
5674 static int
5675 set_designator (int array)
5676 {
5677   tree subtype;
5678   enum tree_code subcode;
5679
5680   /* Don't die if an entire brace-pair level is superfluous
5681      in the containing level.  */
5682   if (constructor_type == 0)
5683     return 1;
5684
5685   /* If there were errors in this designator list already, bail out
5686      silently.  */
5687   if (designator_erroneous)
5688     return 1;
5689
5690   if (!designator_depth)
5691     {
5692       gcc_assert (!constructor_range_stack);
5693
5694       /* Designator list starts at the level of closest explicit
5695          braces.  */
5696       while (constructor_stack->implicit)
5697         process_init_element (pop_init_level (1));
5698       constructor_designated = 1;
5699       return 0;
5700     }
5701
5702   switch (TREE_CODE (constructor_type))
5703     {
5704     case  RECORD_TYPE:
5705     case  UNION_TYPE:
5706       subtype = TREE_TYPE (constructor_fields);
5707       if (subtype != error_mark_node)
5708         subtype = TYPE_MAIN_VARIANT (subtype);
5709       break;
5710     case ARRAY_TYPE:
5711       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5712       break;
5713     default:
5714       gcc_unreachable ();
5715     }
5716
5717   subcode = TREE_CODE (subtype);
5718   if (array && subcode != ARRAY_TYPE)
5719     {
5720       error_init ("array index in non-array initializer");
5721       return 1;
5722     }
5723   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5724     {
5725       error_init ("field name not in record or union initializer");
5726       return 1;
5727     }
5728
5729   constructor_designated = 1;
5730   push_init_level (2);
5731   return 0;
5732 }
5733
5734 /* If there are range designators in designator list, push a new designator
5735    to constructor_range_stack.  RANGE_END is end of such stack range or
5736    NULL_TREE if there is no range designator at this level.  */
5737
5738 static void
5739 push_range_stack (tree range_end)
5740 {
5741   struct constructor_range_stack *p;
5742
5743   p = GGC_NEW (struct constructor_range_stack);
5744   p->prev = constructor_range_stack;
5745   p->next = 0;
5746   p->fields = constructor_fields;
5747   p->range_start = constructor_index;
5748   p->index = constructor_index;
5749   p->stack = constructor_stack;
5750   p->range_end = range_end;
5751   if (constructor_range_stack)
5752     constructor_range_stack->next = p;
5753   constructor_range_stack = p;
5754 }
5755
5756 /* Within an array initializer, specify the next index to be initialized.
5757    FIRST is that index.  If LAST is nonzero, then initialize a range
5758    of indices, running from FIRST through LAST.  */
5759
5760 void
5761 set_init_index (tree first, tree last)
5762 {
5763   if (set_designator (1))
5764     return;
5765
5766   designator_erroneous = 1;
5767
5768   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5769       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5770     {
5771       error_init ("array index in initializer not of integer type");
5772       return;
5773     }
5774
5775   if (TREE_CODE (first) != INTEGER_CST)
5776     error_init ("nonconstant array index in initializer");
5777   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5778     error_init ("nonconstant array index in initializer");
5779   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5780     error_init ("array index in non-array initializer");
5781   else if (tree_int_cst_sgn (first) == -1)
5782     error_init ("array index in initializer exceeds array bounds");
5783   else if (constructor_max_index
5784            && tree_int_cst_lt (constructor_max_index, first))
5785     error_init ("array index in initializer exceeds array bounds");
5786   else
5787     {
5788       constructor_index = convert (bitsizetype, first);
5789
5790       if (last)
5791         {
5792           if (tree_int_cst_equal (first, last))
5793             last = 0;
5794           else if (tree_int_cst_lt (last, first))
5795             {
5796               error_init ("empty index range in initializer");
5797               last = 0;
5798             }
5799           else
5800             {
5801               last = convert (bitsizetype, last);
5802               if (constructor_max_index != 0
5803                   && tree_int_cst_lt (constructor_max_index, last))
5804                 {
5805                   error_init ("array index range in initializer exceeds array bounds");
5806                   last = 0;
5807                 }
5808             }
5809         }
5810
5811       designator_depth++;
5812       designator_erroneous = 0;
5813       if (constructor_range_stack || last)
5814         push_range_stack (last);
5815     }
5816 }
5817
5818 /* Within a struct initializer, specify the next field to be initialized.  */
5819
5820 void
5821 set_init_label (tree fieldname)
5822 {
5823   tree tail;
5824
5825   if (set_designator (0))
5826     return;
5827
5828   designator_erroneous = 1;
5829
5830   if (TREE_CODE (constructor_type) != RECORD_TYPE
5831       && TREE_CODE (constructor_type) != UNION_TYPE)
5832     {
5833       error_init ("field name not in record or union initializer");
5834       return;
5835     }
5836
5837   for (tail = TYPE_FIELDS (constructor_type); tail;
5838        tail = TREE_CHAIN (tail))
5839     {
5840       if (DECL_NAME (tail) == fieldname)
5841         break;
5842     }
5843
5844   if (tail == 0)
5845     error ("unknown field %qE specified in initializer", fieldname);
5846   else
5847     {
5848       constructor_fields = tail;
5849       designator_depth++;
5850       designator_erroneous = 0;
5851       if (constructor_range_stack)
5852         push_range_stack (NULL_TREE);
5853     }
5854 }
5855 \f
5856 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5857    identifies the initializer, either array index or field in a structure.
5858    VALUE is the value of that index or field.  */
5859
5860 static void
5861 add_pending_init (tree purpose, tree value)
5862 {
5863   struct init_node *p, **q, *r;
5864
5865   q = &constructor_pending_elts;
5866   p = 0;
5867
5868   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5869     {
5870       while (*q != 0)
5871         {
5872           p = *q;
5873           if (tree_int_cst_lt (purpose, p->purpose))
5874             q = &p->left;
5875           else if (tree_int_cst_lt (p->purpose, purpose))
5876             q = &p->right;
5877           else
5878             {
5879               if (TREE_SIDE_EFFECTS (p->value))
5880                 warning_init (0, "initialized field with side-effects overwritten");
5881               else if (warn_override_init)
5882                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5883               p->value = value;
5884               return;
5885             }
5886         }
5887     }
5888   else
5889     {
5890       tree bitpos;
5891
5892       bitpos = bit_position (purpose);
5893       while (*q != NULL)
5894         {
5895           p = *q;
5896           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5897             q = &p->left;
5898           else if (p->purpose != purpose)
5899             q = &p->right;
5900           else
5901             {
5902               if (TREE_SIDE_EFFECTS (p->value))
5903                 warning_init (0, "initialized field with side-effects overwritten");
5904               else if (warn_override_init)
5905                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5906               p->value = value;
5907               return;
5908             }
5909         }
5910     }
5911
5912   r = GGC_NEW (struct init_node);
5913   r->purpose = purpose;
5914   r->value = value;
5915
5916   *q = r;
5917   r->parent = p;
5918   r->left = 0;
5919   r->right = 0;
5920   r->balance = 0;
5921
5922   while (p)
5923     {
5924       struct init_node *s;
5925
5926       if (r == p->left)
5927         {
5928           if (p->balance == 0)
5929             p->balance = -1;
5930           else if (p->balance < 0)
5931             {
5932               if (r->balance < 0)
5933                 {
5934                   /* L rotation.  */
5935                   p->left = r->right;
5936                   if (p->left)
5937                     p->left->parent = p;
5938                   r->right = p;
5939
5940                   p->balance = 0;
5941                   r->balance = 0;
5942
5943                   s = p->parent;
5944                   p->parent = r;
5945                   r->parent = s;
5946                   if (s)
5947                     {
5948                       if (s->left == p)
5949                         s->left = r;
5950                       else
5951                         s->right = r;
5952                     }
5953                   else
5954                     constructor_pending_elts = r;
5955                 }
5956               else
5957                 {
5958                   /* LR rotation.  */
5959                   struct init_node *t = r->right;
5960
5961                   r->right = t->left;
5962                   if (r->right)
5963                     r->right->parent = r;
5964                   t->left = r;
5965
5966                   p->left = t->right;
5967                   if (p->left)
5968                     p->left->parent = p;
5969                   t->right = p;
5970
5971                   p->balance = t->balance < 0;
5972                   r->balance = -(t->balance > 0);
5973                   t->balance = 0;
5974
5975                   s = p->parent;
5976                   p->parent = t;
5977                   r->parent = t;
5978                   t->parent = s;
5979                   if (s)
5980                     {
5981                       if (s->left == p)
5982                         s->left = t;
5983                       else
5984                         s->right = t;
5985                     }
5986                   else
5987                     constructor_pending_elts = t;
5988                 }
5989               break;
5990             }
5991           else
5992             {
5993               /* p->balance == +1; growth of left side balances the node.  */
5994               p->balance = 0;
5995               break;
5996             }
5997         }
5998       else /* r == p->right */
5999         {
6000           if (p->balance == 0)
6001             /* Growth propagation from right side.  */
6002             p->balance++;
6003           else if (p->balance > 0)
6004             {
6005               if (r->balance > 0)
6006                 {
6007                   /* R rotation.  */
6008                   p->right = r->left;
6009                   if (p->right)
6010                     p->right->parent = p;
6011                   r->left = p;
6012
6013                   p->balance = 0;
6014                   r->balance = 0;
6015
6016                   s = p->parent;
6017                   p->parent = r;
6018                   r->parent = s;
6019                   if (s)
6020                     {
6021                       if (s->left == p)
6022                         s->left = r;
6023                       else
6024                         s->right = r;
6025                     }
6026                   else
6027                     constructor_pending_elts = r;
6028                 }
6029               else /* r->balance == -1 */
6030                 {
6031                   /* RL rotation */
6032                   struct init_node *t = r->left;
6033
6034                   r->left = t->right;
6035                   if (r->left)
6036                     r->left->parent = r;
6037                   t->right = r;
6038
6039                   p->right = t->left;
6040                   if (p->right)
6041                     p->right->parent = p;
6042                   t->left = p;
6043
6044                   r->balance = (t->balance < 0);
6045                   p->balance = -(t->balance > 0);
6046                   t->balance = 0;
6047
6048                   s = p->parent;
6049                   p->parent = t;
6050                   r->parent = t;
6051                   t->parent = s;
6052                   if (s)
6053                     {
6054                       if (s->left == p)
6055                         s->left = t;
6056                       else
6057                         s->right = t;
6058                     }
6059                   else
6060                     constructor_pending_elts = t;
6061                 }
6062               break;
6063             }
6064           else
6065             {
6066               /* p->balance == -1; growth of right side balances the node.  */
6067               p->balance = 0;
6068               break;
6069             }
6070         }
6071
6072       r = p;
6073       p = p->parent;
6074     }
6075 }
6076
6077 /* Build AVL tree from a sorted chain.  */
6078
6079 static void
6080 set_nonincremental_init (void)
6081 {
6082   unsigned HOST_WIDE_INT ix;
6083   tree index, value;
6084
6085   if (TREE_CODE (constructor_type) != RECORD_TYPE
6086       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6087     return;
6088
6089   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6090     add_pending_init (index, value);
6091   constructor_elements = 0;
6092   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6093     {
6094       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6095       /* Skip any nameless bit fields at the beginning.  */
6096       while (constructor_unfilled_fields != 0
6097              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6098              && DECL_NAME (constructor_unfilled_fields) == 0)
6099         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6100
6101     }
6102   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6103     {
6104       if (TYPE_DOMAIN (constructor_type))
6105         constructor_unfilled_index
6106             = convert (bitsizetype,
6107                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6108       else
6109         constructor_unfilled_index = bitsize_zero_node;
6110     }
6111   constructor_incremental = 0;
6112 }
6113
6114 /* Build AVL tree from a string constant.  */
6115
6116 static void
6117 set_nonincremental_init_from_string (tree str)
6118 {
6119   tree value, purpose, type;
6120   HOST_WIDE_INT val[2];
6121   const char *p, *end;
6122   int byte, wchar_bytes, charwidth, bitpos;
6123
6124   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6125
6126   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6127   charwidth = TYPE_PRECISION (char_type_node);
6128   type = TREE_TYPE (constructor_type);
6129   p = TREE_STRING_POINTER (str);
6130   end = p + TREE_STRING_LENGTH (str);
6131
6132   for (purpose = bitsize_zero_node;
6133        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6134        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6135     {
6136       if (wchar_bytes == 1)
6137         {
6138           val[1] = (unsigned char) *p++;
6139           val[0] = 0;
6140         }
6141       else
6142         {
6143           val[0] = 0;
6144           val[1] = 0;
6145           for (byte = 0; byte < wchar_bytes; byte++)
6146             {
6147               if (BYTES_BIG_ENDIAN)
6148                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6149               else
6150                 bitpos = byte * charwidth;
6151               val[bitpos < HOST_BITS_PER_WIDE_INT]
6152                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6153                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6154             }
6155         }
6156
6157       if (!TYPE_UNSIGNED (type))
6158         {
6159           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6160           if (bitpos < HOST_BITS_PER_WIDE_INT)
6161             {
6162               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6163                 {
6164                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6165                   val[0] = -1;
6166                 }
6167             }
6168           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6169             {
6170               if (val[1] < 0)
6171                 val[0] = -1;
6172             }
6173           else if (val[0] & (((HOST_WIDE_INT) 1)
6174                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6175             val[0] |= ((HOST_WIDE_INT) -1)
6176                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6177         }
6178
6179       value = build_int_cst_wide (type, val[1], val[0]);
6180       add_pending_init (purpose, value);
6181     }
6182
6183   constructor_incremental = 0;
6184 }
6185
6186 /* Return value of FIELD in pending initializer or zero if the field was
6187    not initialized yet.  */
6188
6189 static tree
6190 find_init_member (tree field)
6191 {
6192   struct init_node *p;
6193
6194   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6195     {
6196       if (constructor_incremental
6197           && tree_int_cst_lt (field, constructor_unfilled_index))
6198         set_nonincremental_init ();
6199
6200       p = constructor_pending_elts;
6201       while (p)
6202         {
6203           if (tree_int_cst_lt (field, p->purpose))
6204             p = p->left;
6205           else if (tree_int_cst_lt (p->purpose, field))
6206             p = p->right;
6207           else
6208             return p->value;
6209         }
6210     }
6211   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6212     {
6213       tree bitpos = bit_position (field);
6214
6215       if (constructor_incremental
6216           && (!constructor_unfilled_fields
6217               || tree_int_cst_lt (bitpos,
6218                                   bit_position (constructor_unfilled_fields))))
6219         set_nonincremental_init ();
6220
6221       p = constructor_pending_elts;
6222       while (p)
6223         {
6224           if (field == p->purpose)
6225             return p->value;
6226           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6227             p = p->left;
6228           else
6229             p = p->right;
6230         }
6231     }
6232   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6233     {
6234       if (!VEC_empty (constructor_elt, constructor_elements)
6235           && (VEC_last (constructor_elt, constructor_elements)->index
6236               == field))
6237         return VEC_last (constructor_elt, constructor_elements)->value;
6238     }
6239   return 0;
6240 }
6241
6242 /* "Output" the next constructor element.
6243    At top level, really output it to assembler code now.
6244    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6245    TYPE is the data type that the containing data type wants here.
6246    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6247    If VALUE is a string constant, STRICT_STRING is true if it is
6248    unparenthesized or we should not warn here for it being parenthesized.
6249    For other types of VALUE, STRICT_STRING is not used.
6250
6251    PENDING if non-nil means output pending elements that belong
6252    right after this element.  (PENDING is normally 1;
6253    it is 0 while outputting pending elements, to avoid recursion.)  */
6254
6255 static void
6256 output_init_element (tree value, bool strict_string, tree type, tree field,
6257                      int pending)
6258 {
6259   constructor_elt *celt;
6260
6261   if (type == error_mark_node || value == error_mark_node)
6262     {
6263       constructor_erroneous = 1;
6264       return;
6265     }
6266   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6267       && (TREE_CODE (value) == STRING_CST
6268           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6269       && !(TREE_CODE (value) == STRING_CST
6270            && TREE_CODE (type) == ARRAY_TYPE
6271            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6272       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6273                      TYPE_MAIN_VARIANT (type)))
6274     value = array_to_pointer_conversion (value);
6275
6276   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6277       && require_constant_value && !flag_isoc99 && pending)
6278     {
6279       /* As an extension, allow initializing objects with static storage
6280          duration with compound literals (which are then treated just as
6281          the brace enclosed list they contain).  */
6282       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6283       value = DECL_INITIAL (decl);
6284     }
6285
6286   if (value == error_mark_node)
6287     constructor_erroneous = 1;
6288   else if (!TREE_CONSTANT (value))
6289     constructor_constant = 0;
6290   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6291            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6292                 || TREE_CODE (constructor_type) == UNION_TYPE)
6293                && DECL_C_BIT_FIELD (field)
6294                && TREE_CODE (value) != INTEGER_CST))
6295     constructor_simple = 0;
6296
6297   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6298     {
6299       if (require_constant_value)
6300         {
6301           error_init ("initializer element is not constant");
6302           value = error_mark_node;
6303         }
6304       else if (require_constant_elements)
6305         pedwarn (input_location, 0,
6306                  "initializer element is not computable at load time");
6307     }
6308
6309   /* If this field is empty (and not at the end of structure),
6310      don't do anything other than checking the initializer.  */
6311   if (field
6312       && (TREE_TYPE (field) == error_mark_node
6313           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6314               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6315               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6316                   || TREE_CHAIN (field)))))
6317     return;
6318
6319   value = digest_init (type, value, strict_string, require_constant_value);
6320   if (value == error_mark_node)
6321     {
6322       constructor_erroneous = 1;
6323       return;
6324     }
6325
6326   /* If this element doesn't come next in sequence,
6327      put it on constructor_pending_elts.  */
6328   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6329       && (!constructor_incremental
6330           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6331     {
6332       if (constructor_incremental
6333           && tree_int_cst_lt (field, constructor_unfilled_index))
6334         set_nonincremental_init ();
6335
6336       add_pending_init (field, value);
6337       return;
6338     }
6339   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6340            && (!constructor_incremental
6341                || field != constructor_unfilled_fields))
6342     {
6343       /* We do this for records but not for unions.  In a union,
6344          no matter which field is specified, it can be initialized
6345          right away since it starts at the beginning of the union.  */
6346       if (constructor_incremental)
6347         {
6348           if (!constructor_unfilled_fields)
6349             set_nonincremental_init ();
6350           else
6351             {
6352               tree bitpos, unfillpos;
6353
6354               bitpos = bit_position (field);
6355               unfillpos = bit_position (constructor_unfilled_fields);
6356
6357               if (tree_int_cst_lt (bitpos, unfillpos))
6358                 set_nonincremental_init ();
6359             }
6360         }
6361
6362       add_pending_init (field, value);
6363       return;
6364     }
6365   else if (TREE_CODE (constructor_type) == UNION_TYPE
6366            && !VEC_empty (constructor_elt, constructor_elements))
6367     {
6368       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6369                                        constructor_elements)->value))
6370         warning_init (0, "initialized field with side-effects overwritten");
6371       else if (warn_override_init)
6372         warning_init (OPT_Woverride_init, "initialized field overwritten");
6373
6374       /* We can have just one union field set.  */
6375       constructor_elements = 0;
6376     }
6377
6378   /* Otherwise, output this element either to
6379      constructor_elements or to the assembler file.  */
6380
6381   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6382   celt->index = field;
6383   celt->value = value;
6384
6385   /* Advance the variable that indicates sequential elements output.  */
6386   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6387     constructor_unfilled_index
6388       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6389                     bitsize_one_node);
6390   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6391     {
6392       constructor_unfilled_fields
6393         = TREE_CHAIN (constructor_unfilled_fields);
6394
6395       /* Skip any nameless bit fields.  */
6396       while (constructor_unfilled_fields != 0
6397              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6398              && DECL_NAME (constructor_unfilled_fields) == 0)
6399         constructor_unfilled_fields =
6400           TREE_CHAIN (constructor_unfilled_fields);
6401     }
6402   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6403     constructor_unfilled_fields = 0;
6404
6405   /* Now output any pending elements which have become next.  */
6406   if (pending)
6407     output_pending_init_elements (0);
6408 }
6409
6410 /* Output any pending elements which have become next.
6411    As we output elements, constructor_unfilled_{fields,index}
6412    advances, which may cause other elements to become next;
6413    if so, they too are output.
6414
6415    If ALL is 0, we return when there are
6416    no more pending elements to output now.
6417
6418    If ALL is 1, we output space as necessary so that
6419    we can output all the pending elements.  */
6420
6421 static void
6422 output_pending_init_elements (int all)
6423 {
6424   struct init_node *elt = constructor_pending_elts;
6425   tree next;
6426
6427  retry:
6428
6429   /* Look through the whole pending tree.
6430      If we find an element that should be output now,
6431      output it.  Otherwise, set NEXT to the element
6432      that comes first among those still pending.  */
6433
6434   next = 0;
6435   while (elt)
6436     {
6437       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6438         {
6439           if (tree_int_cst_equal (elt->purpose,
6440                                   constructor_unfilled_index))
6441             output_init_element (elt->value, true,
6442                                  TREE_TYPE (constructor_type),
6443                                  constructor_unfilled_index, 0);
6444           else if (tree_int_cst_lt (constructor_unfilled_index,
6445                                     elt->purpose))
6446             {
6447               /* Advance to the next smaller node.  */
6448               if (elt->left)
6449                 elt = elt->left;
6450               else
6451                 {
6452                   /* We have reached the smallest node bigger than the
6453                      current unfilled index.  Fill the space first.  */
6454                   next = elt->purpose;
6455                   break;
6456                 }
6457             }
6458           else
6459             {
6460               /* Advance to the next bigger node.  */
6461               if (elt->right)
6462                 elt = elt->right;
6463               else
6464                 {
6465                   /* We have reached the biggest node in a subtree.  Find
6466                      the parent of it, which is the next bigger node.  */
6467                   while (elt->parent && elt->parent->right == elt)
6468                     elt = elt->parent;
6469                   elt = elt->parent;
6470                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6471                                               elt->purpose))
6472                     {
6473                       next = elt->purpose;
6474                       break;
6475                     }
6476                 }
6477             }
6478         }
6479       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6480                || TREE_CODE (constructor_type) == UNION_TYPE)
6481         {
6482           tree ctor_unfilled_bitpos, elt_bitpos;
6483
6484           /* If the current record is complete we are done.  */
6485           if (constructor_unfilled_fields == 0)
6486             break;
6487
6488           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6489           elt_bitpos = bit_position (elt->purpose);
6490           /* We can't compare fields here because there might be empty
6491              fields in between.  */
6492           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6493             {
6494               constructor_unfilled_fields = elt->purpose;
6495               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6496                                    elt->purpose, 0);
6497             }
6498           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6499             {
6500               /* Advance to the next smaller node.  */
6501               if (elt->left)
6502                 elt = elt->left;
6503               else
6504                 {
6505                   /* We have reached the smallest node bigger than the
6506                      current unfilled field.  Fill the space first.  */
6507                   next = elt->purpose;
6508                   break;
6509                 }
6510             }
6511           else
6512             {
6513               /* Advance to the next bigger node.  */
6514               if (elt->right)
6515                 elt = elt->right;
6516               else
6517                 {
6518                   /* We have reached the biggest node in a subtree.  Find
6519                      the parent of it, which is the next bigger node.  */
6520                   while (elt->parent && elt->parent->right == elt)
6521                     elt = elt->parent;
6522                   elt = elt->parent;
6523                   if (elt
6524                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6525                                            bit_position (elt->purpose))))
6526                     {
6527                       next = elt->purpose;
6528                       break;
6529                     }
6530                 }
6531             }
6532         }
6533     }
6534
6535   /* Ordinarily return, but not if we want to output all
6536      and there are elements left.  */
6537   if (!(all && next != 0))
6538     return;
6539
6540   /* If it's not incremental, just skip over the gap, so that after
6541      jumping to retry we will output the next successive element.  */
6542   if (TREE_CODE (constructor_type) == RECORD_TYPE
6543       || TREE_CODE (constructor_type) == UNION_TYPE)
6544     constructor_unfilled_fields = next;
6545   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6546     constructor_unfilled_index = next;
6547
6548   /* ELT now points to the node in the pending tree with the next
6549      initializer to output.  */
6550   goto retry;
6551 }
6552 \f
6553 /* Add one non-braced element to the current constructor level.
6554    This adjusts the current position within the constructor's type.
6555    This may also start or terminate implicit levels
6556    to handle a partly-braced initializer.
6557
6558    Once this has found the correct level for the new element,
6559    it calls output_init_element.  */
6560
6561 void
6562 process_init_element (struct c_expr value)
6563 {
6564   tree orig_value = value.value;
6565   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6566   bool strict_string = value.original_code == STRING_CST;
6567
6568   designator_depth = 0;
6569   designator_erroneous = 0;
6570
6571   /* Handle superfluous braces around string cst as in
6572      char x[] = {"foo"}; */
6573   if (string_flag
6574       && constructor_type
6575       && TREE_CODE (constructor_type) == ARRAY_TYPE
6576       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6577       && integer_zerop (constructor_unfilled_index))
6578     {
6579       if (constructor_stack->replacement_value.value)
6580         error_init ("excess elements in char array initializer");
6581       constructor_stack->replacement_value = value;
6582       return;
6583     }
6584
6585   if (constructor_stack->replacement_value.value != 0)
6586     {
6587       error_init ("excess elements in struct initializer");
6588       return;
6589     }
6590
6591   /* Ignore elements of a brace group if it is entirely superfluous
6592      and has already been diagnosed.  */
6593   if (constructor_type == 0)
6594     return;
6595
6596   /* If we've exhausted any levels that didn't have braces,
6597      pop them now.  */
6598   while (constructor_stack->implicit)
6599     {
6600       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6601            || TREE_CODE (constructor_type) == UNION_TYPE)
6602           && constructor_fields == 0)
6603         process_init_element (pop_init_level (1));
6604       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6605                && (constructor_max_index == 0
6606                    || tree_int_cst_lt (constructor_max_index,
6607                                        constructor_index)))
6608         process_init_element (pop_init_level (1));
6609       else
6610         break;
6611     }
6612
6613   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6614   if (constructor_range_stack)
6615     {
6616       /* If value is a compound literal and we'll be just using its
6617          content, don't put it into a SAVE_EXPR.  */
6618       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6619           || !require_constant_value
6620           || flag_isoc99)
6621         value.value = save_expr (value.value);
6622     }
6623
6624   while (1)
6625     {
6626       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6627         {
6628           tree fieldtype;
6629           enum tree_code fieldcode;
6630
6631           if (constructor_fields == 0)
6632             {
6633               pedwarn_init (input_location, 0,
6634                             "excess elements in struct initializer");
6635               break;
6636             }
6637
6638           fieldtype = TREE_TYPE (constructor_fields);
6639           if (fieldtype != error_mark_node)
6640             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6641           fieldcode = TREE_CODE (fieldtype);
6642
6643           /* Error for non-static initialization of a flexible array member.  */
6644           if (fieldcode == ARRAY_TYPE
6645               && !require_constant_value
6646               && TYPE_SIZE (fieldtype) == NULL_TREE
6647               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6648             {
6649               error_init ("non-static initialization of a flexible array member");
6650               break;
6651             }
6652
6653           /* Accept a string constant to initialize a subarray.  */
6654           if (value.value != 0
6655               && fieldcode == ARRAY_TYPE
6656               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6657               && string_flag)
6658             value.value = orig_value;
6659           /* Otherwise, if we have come to a subaggregate,
6660              and we don't have an element of its type, push into it.  */
6661           else if (value.value != 0
6662                    && value.value != error_mark_node
6663                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6664                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6665                        || fieldcode == UNION_TYPE))
6666             {
6667               push_init_level (1);
6668               continue;
6669             }
6670
6671           if (value.value)
6672             {
6673               push_member_name (constructor_fields);
6674               output_init_element (value.value, strict_string,
6675                                    fieldtype, constructor_fields, 1);
6676               RESTORE_SPELLING_DEPTH (constructor_depth);
6677             }
6678           else
6679             /* Do the bookkeeping for an element that was
6680                directly output as a constructor.  */
6681             {
6682               /* For a record, keep track of end position of last field.  */
6683               if (DECL_SIZE (constructor_fields))
6684                 constructor_bit_index
6685                   = size_binop (PLUS_EXPR,
6686                                 bit_position (constructor_fields),
6687                                 DECL_SIZE (constructor_fields));
6688
6689               /* If the current field was the first one not yet written out,
6690                  it isn't now, so update.  */
6691               if (constructor_unfilled_fields == constructor_fields)
6692                 {
6693                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6694                   /* Skip any nameless bit fields.  */
6695                   while (constructor_unfilled_fields != 0
6696                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6697                          && DECL_NAME (constructor_unfilled_fields) == 0)
6698                     constructor_unfilled_fields =
6699                       TREE_CHAIN (constructor_unfilled_fields);
6700                 }
6701             }
6702
6703           constructor_fields = TREE_CHAIN (constructor_fields);
6704           /* Skip any nameless bit fields at the beginning.  */
6705           while (constructor_fields != 0
6706                  && DECL_C_BIT_FIELD (constructor_fields)
6707                  && DECL_NAME (constructor_fields) == 0)
6708             constructor_fields = TREE_CHAIN (constructor_fields);
6709         }
6710       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6711         {
6712           tree fieldtype;
6713           enum tree_code fieldcode;
6714
6715           if (constructor_fields == 0)
6716             {
6717               pedwarn_init (input_location, 0,
6718                             "excess elements in union initializer");
6719               break;
6720             }
6721
6722           fieldtype = TREE_TYPE (constructor_fields);
6723           if (fieldtype != error_mark_node)
6724             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6725           fieldcode = TREE_CODE (fieldtype);
6726
6727           /* Warn that traditional C rejects initialization of unions.
6728              We skip the warning if the value is zero.  This is done
6729              under the assumption that the zero initializer in user
6730              code appears conditioned on e.g. __STDC__ to avoid
6731              "missing initializer" warnings and relies on default
6732              initialization to zero in the traditional C case.
6733              We also skip the warning if the initializer is designated,
6734              again on the assumption that this must be conditional on
6735              __STDC__ anyway (and we've already complained about the
6736              member-designator already).  */
6737           if (!in_system_header && !constructor_designated
6738               && !(value.value && (integer_zerop (value.value)
6739                                    || real_zerop (value.value))))
6740             warning (OPT_Wtraditional, "traditional C rejects initialization "
6741                      "of unions");
6742
6743           /* Accept a string constant to initialize a subarray.  */
6744           if (value.value != 0
6745               && fieldcode == ARRAY_TYPE
6746               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6747               && string_flag)
6748             value.value = orig_value;
6749           /* Otherwise, if we have come to a subaggregate,
6750              and we don't have an element of its type, push into it.  */
6751           else if (value.value != 0
6752                    && value.value != error_mark_node
6753                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6754                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6755                        || fieldcode == UNION_TYPE))
6756             {
6757               push_init_level (1);
6758               continue;
6759             }
6760
6761           if (value.value)
6762             {
6763               push_member_name (constructor_fields);
6764               output_init_element (value.value, strict_string,
6765                                    fieldtype, constructor_fields, 1);
6766               RESTORE_SPELLING_DEPTH (constructor_depth);
6767             }
6768           else
6769             /* Do the bookkeeping for an element that was
6770                directly output as a constructor.  */
6771             {
6772               constructor_bit_index = DECL_SIZE (constructor_fields);
6773               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6774             }
6775
6776           constructor_fields = 0;
6777         }
6778       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6779         {
6780           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6781           enum tree_code eltcode = TREE_CODE (elttype);
6782
6783           /* Accept a string constant to initialize a subarray.  */
6784           if (value.value != 0
6785               && eltcode == ARRAY_TYPE
6786               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6787               && string_flag)
6788             value.value = orig_value;
6789           /* Otherwise, if we have come to a subaggregate,
6790              and we don't have an element of its type, push into it.  */
6791           else if (value.value != 0
6792                    && value.value != error_mark_node
6793                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6794                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6795                        || eltcode == UNION_TYPE))
6796             {
6797               push_init_level (1);
6798               continue;
6799             }
6800
6801           if (constructor_max_index != 0
6802               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6803                   || integer_all_onesp (constructor_max_index)))
6804             {
6805               pedwarn_init (input_location, 0,
6806                             "excess elements in array initializer");
6807               break;
6808             }
6809
6810           /* Now output the actual element.  */
6811           if (value.value)
6812             {
6813               push_array_bounds (tree_low_cst (constructor_index, 1));
6814               output_init_element (value.value, strict_string,
6815                                    elttype, constructor_index, 1);
6816               RESTORE_SPELLING_DEPTH (constructor_depth);
6817             }
6818
6819           constructor_index
6820             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6821
6822           if (!value.value)
6823             /* If we are doing the bookkeeping for an element that was
6824                directly output as a constructor, we must update
6825                constructor_unfilled_index.  */
6826             constructor_unfilled_index = constructor_index;
6827         }
6828       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6829         {
6830           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6831
6832          /* Do a basic check of initializer size.  Note that vectors
6833             always have a fixed size derived from their type.  */
6834           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6835             {
6836               pedwarn_init (input_location, 0,
6837                             "excess elements in vector initializer");
6838               break;
6839             }
6840
6841           /* Now output the actual element.  */
6842           if (value.value)
6843             output_init_element (value.value, strict_string,
6844                                  elttype, constructor_index, 1);
6845
6846           constructor_index
6847             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6848
6849           if (!value.value)
6850             /* If we are doing the bookkeeping for an element that was
6851                directly output as a constructor, we must update
6852                constructor_unfilled_index.  */
6853             constructor_unfilled_index = constructor_index;
6854         }
6855
6856       /* Handle the sole element allowed in a braced initializer
6857          for a scalar variable.  */
6858       else if (constructor_type != error_mark_node
6859                && constructor_fields == 0)
6860         {
6861           pedwarn_init (input_location, 0,
6862                         "excess elements in scalar initializer");
6863           break;
6864         }
6865       else
6866         {
6867           if (value.value)
6868             output_init_element (value.value, strict_string,
6869                                  constructor_type, NULL_TREE, 1);
6870           constructor_fields = 0;
6871         }
6872
6873       /* Handle range initializers either at this level or anywhere higher
6874          in the designator stack.  */
6875       if (constructor_range_stack)
6876         {
6877           struct constructor_range_stack *p, *range_stack;
6878           int finish = 0;
6879
6880           range_stack = constructor_range_stack;
6881           constructor_range_stack = 0;
6882           while (constructor_stack != range_stack->stack)
6883             {
6884               gcc_assert (constructor_stack->implicit);
6885               process_init_element (pop_init_level (1));
6886             }
6887           for (p = range_stack;
6888                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6889                p = p->prev)
6890             {
6891               gcc_assert (constructor_stack->implicit);
6892               process_init_element (pop_init_level (1));
6893             }
6894
6895           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6896           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6897             finish = 1;
6898
6899           while (1)
6900             {
6901               constructor_index = p->index;
6902               constructor_fields = p->fields;
6903               if (finish && p->range_end && p->index == p->range_start)
6904                 {
6905                   finish = 0;
6906                   p->prev = 0;
6907                 }
6908               p = p->next;
6909               if (!p)
6910                 break;
6911               push_init_level (2);
6912               p->stack = constructor_stack;
6913               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6914                 p->index = p->range_start;
6915             }
6916
6917           if (!finish)
6918             constructor_range_stack = range_stack;
6919           continue;
6920         }
6921
6922       break;
6923     }
6924
6925   constructor_range_stack = 0;
6926 }
6927 \f
6928 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6929    (guaranteed to be 'volatile' or null) and ARGS (represented using
6930    an ASM_EXPR node).  */
6931 tree
6932 build_asm_stmt (tree cv_qualifier, tree args)
6933 {
6934   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6935     ASM_VOLATILE_P (args) = 1;
6936   return add_stmt (args);
6937 }
6938
6939 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6940    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6941    SIMPLE indicates whether there was anything at all after the
6942    string in the asm expression -- asm("blah") and asm("blah" : )
6943    are subtly different.  We use a ASM_EXPR node to represent this.  */
6944 tree
6945 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6946                 bool simple)
6947 {
6948   tree tail;
6949   tree args;
6950   int i;
6951   const char *constraint;
6952   const char **oconstraints;
6953   bool allows_mem, allows_reg, is_inout;
6954   int ninputs, noutputs;
6955
6956   ninputs = list_length (inputs);
6957   noutputs = list_length (outputs);
6958   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6959
6960   string = resolve_asm_operand_names (string, outputs, inputs);
6961
6962   /* Remove output conversions that change the type but not the mode.  */
6963   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6964     {
6965       tree output = TREE_VALUE (tail);
6966
6967       /* ??? Really, this should not be here.  Users should be using a
6968          proper lvalue, dammit.  But there's a long history of using casts
6969          in the output operands.  In cases like longlong.h, this becomes a
6970          primitive form of typechecking -- if the cast can be removed, then
6971          the output operand had a type of the proper width; otherwise we'll
6972          get an error.  Gross, but ...  */
6973       STRIP_NOPS (output);
6974
6975       if (!lvalue_or_else (output, lv_asm))
6976         output = error_mark_node;
6977
6978       if (output != error_mark_node
6979           && (TREE_READONLY (output)
6980               || TYPE_READONLY (TREE_TYPE (output))
6981               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6982                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6983                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6984         readonly_error (output, lv_asm);
6985
6986       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6987       oconstraints[i] = constraint;
6988
6989       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6990                                    &allows_mem, &allows_reg, &is_inout))
6991         {
6992           /* If the operand is going to end up in memory,
6993              mark it addressable.  */
6994           if (!allows_reg && !c_mark_addressable (output))
6995             output = error_mark_node;
6996         }
6997       else
6998         output = error_mark_node;
6999
7000       TREE_VALUE (tail) = output;
7001     }
7002
7003   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7004     {
7005       tree input;
7006
7007       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7008       input = TREE_VALUE (tail);
7009
7010       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7011                                   oconstraints, &allows_mem, &allows_reg))
7012         {
7013           /* If the operand is going to end up in memory,
7014              mark it addressable.  */
7015           if (!allows_reg && allows_mem)
7016             {
7017               /* Strip the nops as we allow this case.  FIXME, this really
7018                  should be rejected or made deprecated.  */
7019               STRIP_NOPS (input);
7020               if (!c_mark_addressable (input))
7021                 input = error_mark_node;
7022           }
7023         }
7024       else
7025         input = error_mark_node;
7026
7027       TREE_VALUE (tail) = input;
7028     }
7029
7030   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7031
7032   /* asm statements without outputs, including simple ones, are treated
7033      as volatile.  */
7034   ASM_INPUT_P (args) = simple;
7035   ASM_VOLATILE_P (args) = (noutputs == 0);
7036
7037   return args;
7038 }
7039 \f
7040 /* Generate a goto statement to LABEL.  */
7041
7042 tree
7043 c_finish_goto_label (tree label)
7044 {
7045   tree decl = lookup_label (label);
7046   if (!decl)
7047     return NULL_TREE;
7048
7049   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7050     {
7051       error ("jump into statement expression");
7052       return NULL_TREE;
7053     }
7054
7055   if (C_DECL_UNJUMPABLE_VM (decl))
7056     {
7057       error ("jump into scope of identifier with variably modified type");
7058       return NULL_TREE;
7059     }
7060
7061   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7062     {
7063       /* No jump from outside this statement expression context, so
7064          record that there is a jump from within this context.  */
7065       struct c_label_list *nlist;
7066       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7067       nlist->next = label_context_stack_se->labels_used;
7068       nlist->label = decl;
7069       label_context_stack_se->labels_used = nlist;
7070     }
7071
7072   if (!C_DECL_UNDEFINABLE_VM (decl))
7073     {
7074       /* No jump from outside this context context of identifiers with
7075          variably modified type, so record that there is a jump from
7076          within this context.  */
7077       struct c_label_list *nlist;
7078       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7079       nlist->next = label_context_stack_vm->labels_used;
7080       nlist->label = decl;
7081       label_context_stack_vm->labels_used = nlist;
7082     }
7083
7084   TREE_USED (decl) = 1;
7085   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7086 }
7087
7088 /* Generate a computed goto statement to EXPR.  */
7089
7090 tree
7091 c_finish_goto_ptr (tree expr)
7092 {
7093   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7094   expr = convert (ptr_type_node, expr);
7095   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7096 }
7097
7098 /* Generate a C `return' statement.  RETVAL is the expression for what
7099    to return, or a null pointer for `return;' with no value.  */
7100
7101 tree
7102 c_finish_return (tree retval)
7103 {
7104   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7105   bool no_warning = false;
7106
7107   if (TREE_THIS_VOLATILE (current_function_decl))
7108     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7109
7110   if (!retval)
7111     {
7112       current_function_returns_null = 1;
7113       if ((warn_return_type || flag_isoc99)
7114           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7115         {
7116           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7117                        "%<return%> with no value, in "
7118                        "function returning non-void");
7119           no_warning = true;
7120         }
7121     }
7122   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7123     {
7124       current_function_returns_null = 1;
7125       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7126         pedwarn (input_location, 0,
7127                  "%<return%> with a value, in function returning void");
7128       else
7129         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7130                  "%<return%> with expression, in function returning void");
7131     }
7132   else
7133     {
7134       tree t = convert_for_assignment (valtype, retval, ic_return,
7135                                        NULL_TREE, NULL_TREE, 0);
7136       tree res = DECL_RESULT (current_function_decl);
7137       tree inner;
7138
7139       current_function_returns_value = 1;
7140       if (t == error_mark_node)
7141         return NULL_TREE;
7142
7143       inner = t = convert (TREE_TYPE (res), t);
7144
7145       /* Strip any conversions, additions, and subtractions, and see if
7146          we are returning the address of a local variable.  Warn if so.  */
7147       while (1)
7148         {
7149           switch (TREE_CODE (inner))
7150             {
7151             CASE_CONVERT:   case NON_LVALUE_EXPR:
7152             case PLUS_EXPR:
7153               inner = TREE_OPERAND (inner, 0);
7154               continue;
7155
7156             case MINUS_EXPR:
7157               /* If the second operand of the MINUS_EXPR has a pointer
7158                  type (or is converted from it), this may be valid, so
7159                  don't give a warning.  */
7160               {
7161                 tree op1 = TREE_OPERAND (inner, 1);
7162
7163                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7164                        && (CONVERT_EXPR_P (op1)
7165                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7166                   op1 = TREE_OPERAND (op1, 0);
7167
7168                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7169                   break;
7170
7171                 inner = TREE_OPERAND (inner, 0);
7172                 continue;
7173               }
7174
7175             case ADDR_EXPR:
7176               inner = TREE_OPERAND (inner, 0);
7177
7178               while (REFERENCE_CLASS_P (inner)
7179                      && TREE_CODE (inner) != INDIRECT_REF)
7180                 inner = TREE_OPERAND (inner, 0);
7181
7182               if (DECL_P (inner)
7183                   && !DECL_EXTERNAL (inner)
7184                   && !TREE_STATIC (inner)
7185                   && DECL_CONTEXT (inner) == current_function_decl)
7186                 warning (0, "function returns address of local variable");
7187               break;
7188
7189             default:
7190               break;
7191             }
7192
7193           break;
7194         }
7195
7196       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7197
7198       if (warn_sequence_point)
7199         verify_sequence_points (retval);
7200     }
7201
7202   ret_stmt = build_stmt (RETURN_EXPR, retval);
7203   TREE_NO_WARNING (ret_stmt) |= no_warning;
7204   return add_stmt (ret_stmt);
7205 }
7206 \f
7207 struct c_switch {
7208   /* The SWITCH_EXPR being built.  */
7209   tree switch_expr;
7210
7211   /* The original type of the testing expression, i.e. before the
7212      default conversion is applied.  */
7213   tree orig_type;
7214
7215   /* A splay-tree mapping the low element of a case range to the high
7216      element, or NULL_TREE if there is no high element.  Used to
7217      determine whether or not a new case label duplicates an old case
7218      label.  We need a tree, rather than simply a hash table, because
7219      of the GNU case range extension.  */
7220   splay_tree cases;
7221
7222   /* Number of nested statement expressions within this switch
7223      statement; if nonzero, case and default labels may not
7224      appear.  */
7225   unsigned int blocked_stmt_expr;
7226
7227   /* Scope of outermost declarations of identifiers with variably
7228      modified type within this switch statement; if nonzero, case and
7229      default labels may not appear.  */
7230   unsigned int blocked_vm;
7231
7232   /* The next node on the stack.  */
7233   struct c_switch *next;
7234 };
7235
7236 /* A stack of the currently active switch statements.  The innermost
7237    switch statement is on the top of the stack.  There is no need to
7238    mark the stack for garbage collection because it is only active
7239    during the processing of the body of a function, and we never
7240    collect at that point.  */
7241
7242 struct c_switch *c_switch_stack;
7243
7244 /* Start a C switch statement, testing expression EXP.  Return the new
7245    SWITCH_EXPR.  */
7246
7247 tree
7248 c_start_case (tree exp)
7249 {
7250   tree orig_type = error_mark_node;
7251   struct c_switch *cs;
7252
7253   if (exp != error_mark_node)
7254     {
7255       orig_type = TREE_TYPE (exp);
7256
7257       if (!INTEGRAL_TYPE_P (orig_type))
7258         {
7259           if (orig_type != error_mark_node)
7260             {
7261               error ("switch quantity not an integer");
7262               orig_type = error_mark_node;
7263             }
7264           exp = integer_zero_node;
7265         }
7266       else
7267         {
7268           tree type = TYPE_MAIN_VARIANT (orig_type);
7269
7270           if (!in_system_header
7271               && (type == long_integer_type_node
7272                   || type == long_unsigned_type_node))
7273             warning (OPT_Wtraditional, "%<long%> switch expression not "
7274                      "converted to %<int%> in ISO C");
7275
7276           exp = default_conversion (exp);
7277
7278           if (warn_sequence_point)
7279             verify_sequence_points (exp);
7280         }
7281     }
7282
7283   /* Add this new SWITCH_EXPR to the stack.  */
7284   cs = XNEW (struct c_switch);
7285   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7286   cs->orig_type = orig_type;
7287   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7288   cs->blocked_stmt_expr = 0;
7289   cs->blocked_vm = 0;
7290   cs->next = c_switch_stack;
7291   c_switch_stack = cs;
7292
7293   return add_stmt (cs->switch_expr);
7294 }
7295
7296 /* Process a case label.  */
7297
7298 tree
7299 do_case (tree low_value, tree high_value)
7300 {
7301   tree label = NULL_TREE;
7302
7303   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7304       && !c_switch_stack->blocked_vm)
7305     {
7306       label = c_add_case_label (c_switch_stack->cases,
7307                                 SWITCH_COND (c_switch_stack->switch_expr),
7308                                 c_switch_stack->orig_type,
7309                                 low_value, high_value);
7310       if (label == error_mark_node)
7311         label = NULL_TREE;
7312     }
7313   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7314     {
7315       if (low_value)
7316         error ("case label in statement expression not containing "
7317                "enclosing switch statement");
7318       else
7319         error ("%<default%> label in statement expression not containing "
7320                "enclosing switch statement");
7321     }
7322   else if (c_switch_stack && c_switch_stack->blocked_vm)
7323     {
7324       if (low_value)
7325         error ("case label in scope of identifier with variably modified "
7326                "type not containing enclosing switch statement");
7327       else
7328         error ("%<default%> label in scope of identifier with variably "
7329                "modified type not containing enclosing switch statement");
7330     }
7331   else if (low_value)
7332     error ("case label not within a switch statement");
7333   else
7334     error ("%<default%> label not within a switch statement");
7335
7336   return label;
7337 }
7338
7339 /* Finish the switch statement.  */
7340
7341 void
7342 c_finish_case (tree body)
7343 {
7344   struct c_switch *cs = c_switch_stack;
7345   location_t switch_location;
7346
7347   SWITCH_BODY (cs->switch_expr) = body;
7348
7349   /* We must not be within a statement expression nested in the switch
7350      at this point; we might, however, be within the scope of an
7351      identifier with variably modified type nested in the switch.  */
7352   gcc_assert (!cs->blocked_stmt_expr);
7353
7354   /* Emit warnings as needed.  */
7355   if (EXPR_HAS_LOCATION (cs->switch_expr))
7356     switch_location = EXPR_LOCATION (cs->switch_expr);
7357   else
7358     switch_location = input_location;
7359   c_do_switch_warnings (cs->cases, switch_location,
7360                         TREE_TYPE (cs->switch_expr),
7361                         SWITCH_COND (cs->switch_expr));
7362
7363   /* Pop the stack.  */
7364   c_switch_stack = cs->next;
7365   splay_tree_delete (cs->cases);
7366   XDELETE (cs);
7367 }
7368 \f
7369 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7370    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7371    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7372    statement, and was not surrounded with parenthesis.  */
7373
7374 void
7375 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7376                   tree else_block, bool nested_if)
7377 {
7378   tree stmt;
7379
7380   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7381   if (warn_parentheses && nested_if && else_block == NULL)
7382     {
7383       tree inner_if = then_block;
7384
7385       /* We know from the grammar productions that there is an IF nested
7386          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7387          it might not be exactly THEN_BLOCK, but should be the last
7388          non-container statement within.  */
7389       while (1)
7390         switch (TREE_CODE (inner_if))
7391           {
7392           case COND_EXPR:
7393             goto found;
7394           case BIND_EXPR:
7395             inner_if = BIND_EXPR_BODY (inner_if);
7396             break;
7397           case STATEMENT_LIST:
7398             inner_if = expr_last (then_block);
7399             break;
7400           case TRY_FINALLY_EXPR:
7401           case TRY_CATCH_EXPR:
7402             inner_if = TREE_OPERAND (inner_if, 0);
7403             break;
7404           default:
7405             gcc_unreachable ();
7406           }
7407     found:
7408
7409       if (COND_EXPR_ELSE (inner_if))
7410          warning (OPT_Wparentheses,
7411                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7412                   &if_locus);
7413     }
7414
7415   empty_if_body_warning (then_block, else_block);
7416
7417   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7418   SET_EXPR_LOCATION (stmt, if_locus);
7419   add_stmt (stmt);
7420 }
7421
7422 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7423    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7424    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7425    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7426    the continue label.  Everything is allowed to be NULL.  */
7427
7428 void
7429 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7430                tree blab, tree clab, bool cond_is_first)
7431 {
7432   tree entry = NULL, exit = NULL, t;
7433
7434   /* If the condition is zero don't generate a loop construct.  */
7435   if (cond && integer_zerop (cond))
7436     {
7437       if (cond_is_first)
7438         {
7439           t = build_and_jump (&blab);
7440           SET_EXPR_LOCATION (t, start_locus);
7441           add_stmt (t);
7442         }
7443     }
7444   else
7445     {
7446       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7447
7448       /* If we have an exit condition, then we build an IF with gotos either
7449          out of the loop, or to the top of it.  If there's no exit condition,
7450          then we just build a jump back to the top.  */
7451       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7452
7453       if (cond && !integer_nonzerop (cond))
7454         {
7455           /* Canonicalize the loop condition to the end.  This means
7456              generating a branch to the loop condition.  Reuse the
7457              continue label, if possible.  */
7458           if (cond_is_first)
7459             {
7460               if (incr || !clab)
7461                 {
7462                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7463                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7464                 }
7465               else
7466                 t = build1 (GOTO_EXPR, void_type_node, clab);
7467               SET_EXPR_LOCATION (t, start_locus);
7468               add_stmt (t);
7469             }
7470
7471           t = build_and_jump (&blab);
7472           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7473           if (cond_is_first)
7474             SET_EXPR_LOCATION (exit, start_locus);
7475           else
7476             SET_EXPR_LOCATION (exit, input_location);
7477         }
7478
7479       add_stmt (top);
7480     }
7481
7482   if (body)
7483     add_stmt (body);
7484   if (clab)
7485     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7486   if (incr)
7487     add_stmt (incr);
7488   if (entry)
7489     add_stmt (entry);
7490   if (exit)
7491     add_stmt (exit);
7492   if (blab)
7493     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7494 }
7495
7496 tree
7497 c_finish_bc_stmt (tree *label_p, bool is_break)
7498 {
7499   bool skip;
7500   tree label = *label_p;
7501
7502   /* In switch statements break is sometimes stylistically used after
7503      a return statement.  This can lead to spurious warnings about
7504      control reaching the end of a non-void function when it is
7505      inlined.  Note that we are calling block_may_fallthru with
7506      language specific tree nodes; this works because
7507      block_may_fallthru returns true when given something it does not
7508      understand.  */
7509   skip = !block_may_fallthru (cur_stmt_list);
7510
7511   if (!label)
7512     {
7513       if (!skip)
7514         *label_p = label = create_artificial_label ();
7515     }
7516   else if (TREE_CODE (label) == LABEL_DECL)
7517     ;
7518   else switch (TREE_INT_CST_LOW (label))
7519     {
7520     case 0:
7521       if (is_break)
7522         error ("break statement not within loop or switch");
7523       else
7524         error ("continue statement not within a loop");
7525       return NULL_TREE;
7526
7527     case 1:
7528       gcc_assert (is_break);
7529       error ("break statement used with OpenMP for loop");
7530       return NULL_TREE;
7531
7532     default:
7533       gcc_unreachable ();
7534     }
7535
7536   if (skip)
7537     return NULL_TREE;
7538
7539   if (!is_break)
7540     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7541
7542   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7543 }
7544
7545 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7546
7547 static void
7548 emit_side_effect_warnings (tree expr)
7549 {
7550   if (expr == error_mark_node)
7551     ;
7552   else if (!TREE_SIDE_EFFECTS (expr))
7553     {
7554       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7555         warning (OPT_Wunused_value, "%Hstatement with no effect",
7556                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7557     }
7558   else
7559     warn_if_unused_value (expr, input_location);
7560 }
7561
7562 /* Process an expression as if it were a complete statement.  Emit
7563    diagnostics, but do not call ADD_STMT.  */
7564
7565 tree
7566 c_process_expr_stmt (tree expr)
7567 {
7568   if (!expr)
7569     return NULL_TREE;
7570
7571   if (warn_sequence_point)
7572     verify_sequence_points (expr);
7573
7574   if (TREE_TYPE (expr) != error_mark_node
7575       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7576       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7577     error ("expression statement has incomplete type");
7578
7579   /* If we're not processing a statement expression, warn about unused values.
7580      Warnings for statement expressions will be emitted later, once we figure
7581      out which is the result.  */
7582   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7583       && warn_unused_value)
7584     emit_side_effect_warnings (expr);
7585
7586   /* If the expression is not of a type to which we cannot assign a line
7587      number, wrap the thing in a no-op NOP_EXPR.  */
7588   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7589     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7590
7591   if (CAN_HAVE_LOCATION_P (expr))
7592     SET_EXPR_LOCATION (expr, input_location);
7593
7594   return expr;
7595 }
7596
7597 /* Emit an expression as a statement.  */
7598
7599 tree
7600 c_finish_expr_stmt (tree expr)
7601 {
7602   if (expr)
7603     return add_stmt (c_process_expr_stmt (expr));
7604   else
7605     return NULL;
7606 }
7607
7608 /* Do the opposite and emit a statement as an expression.  To begin,
7609    create a new binding level and return it.  */
7610
7611 tree
7612 c_begin_stmt_expr (void)
7613 {
7614   tree ret;
7615   struct c_label_context_se *nstack;
7616   struct c_label_list *glist;
7617
7618   /* We must force a BLOCK for this level so that, if it is not expanded
7619      later, there is a way to turn off the entire subtree of blocks that
7620      are contained in it.  */
7621   keep_next_level ();
7622   ret = c_begin_compound_stmt (true);
7623   if (c_switch_stack)
7624     {
7625       c_switch_stack->blocked_stmt_expr++;
7626       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7627     }
7628   for (glist = label_context_stack_se->labels_used;
7629        glist != NULL;
7630        glist = glist->next)
7631     {
7632       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7633     }
7634   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7635   nstack->labels_def = NULL;
7636   nstack->labels_used = NULL;
7637   nstack->next = label_context_stack_se;
7638   label_context_stack_se = nstack;
7639
7640   /* Mark the current statement list as belonging to a statement list.  */
7641   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7642
7643   return ret;
7644 }
7645
7646 tree
7647 c_finish_stmt_expr (tree body)
7648 {
7649   tree last, type, tmp, val;
7650   tree *last_p;
7651   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7652
7653   body = c_end_compound_stmt (body, true);
7654   if (c_switch_stack)
7655     {
7656       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7657       c_switch_stack->blocked_stmt_expr--;
7658     }
7659   /* It is no longer possible to jump to labels defined within this
7660      statement expression.  */
7661   for (dlist = label_context_stack_se->labels_def;
7662        dlist != NULL;
7663        dlist = dlist->next)
7664     {
7665       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7666     }
7667   /* It is again possible to define labels with a goto just outside
7668      this statement expression.  */
7669   for (glist = label_context_stack_se->next->labels_used;
7670        glist != NULL;
7671        glist = glist->next)
7672     {
7673       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7674       glist_prev = glist;
7675     }
7676   if (glist_prev != NULL)
7677     glist_prev->next = label_context_stack_se->labels_used;
7678   else
7679     label_context_stack_se->next->labels_used
7680       = label_context_stack_se->labels_used;
7681   label_context_stack_se = label_context_stack_se->next;
7682
7683   /* Locate the last statement in BODY.  See c_end_compound_stmt
7684      about always returning a BIND_EXPR.  */
7685   last_p = &BIND_EXPR_BODY (body);
7686   last = BIND_EXPR_BODY (body);
7687
7688  continue_searching:
7689   if (TREE_CODE (last) == STATEMENT_LIST)
7690     {
7691       tree_stmt_iterator i;
7692
7693       /* This can happen with degenerate cases like ({ }).  No value.  */
7694       if (!TREE_SIDE_EFFECTS (last))
7695         return body;
7696
7697       /* If we're supposed to generate side effects warnings, process
7698          all of the statements except the last.  */
7699       if (warn_unused_value)
7700         {
7701           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7702             emit_side_effect_warnings (tsi_stmt (i));
7703         }
7704       else
7705         i = tsi_last (last);
7706       last_p = tsi_stmt_ptr (i);
7707       last = *last_p;
7708     }
7709
7710   /* If the end of the list is exception related, then the list was split
7711      by a call to push_cleanup.  Continue searching.  */
7712   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7713       || TREE_CODE (last) == TRY_CATCH_EXPR)
7714     {
7715       last_p = &TREE_OPERAND (last, 0);
7716       last = *last_p;
7717       goto continue_searching;
7718     }
7719
7720   /* In the case that the BIND_EXPR is not necessary, return the
7721      expression out from inside it.  */
7722   if (last == error_mark_node
7723       || (last == BIND_EXPR_BODY (body)
7724           && BIND_EXPR_VARS (body) == NULL))
7725     {
7726       /* Do not warn if the return value of a statement expression is
7727          unused.  */
7728       if (CAN_HAVE_LOCATION_P (last))
7729         TREE_NO_WARNING (last) = 1;
7730       return last;
7731     }
7732
7733   /* Extract the type of said expression.  */
7734   type = TREE_TYPE (last);
7735
7736   /* If we're not returning a value at all, then the BIND_EXPR that
7737      we already have is a fine expression to return.  */
7738   if (!type || VOID_TYPE_P (type))
7739     return body;
7740
7741   /* Now that we've located the expression containing the value, it seems
7742      silly to make voidify_wrapper_expr repeat the process.  Create a
7743      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7744   tmp = create_tmp_var_raw (type, NULL);
7745
7746   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7747      tree_expr_nonnegative_p giving up immediately.  */
7748   val = last;
7749   if (TREE_CODE (val) == NOP_EXPR
7750       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7751     val = TREE_OPERAND (val, 0);
7752
7753   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7754   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7755
7756   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7757 }
7758
7759 /* Begin the scope of an identifier of variably modified type, scope
7760    number SCOPE.  Jumping from outside this scope to inside it is not
7761    permitted.  */
7762
7763 void
7764 c_begin_vm_scope (unsigned int scope)
7765 {
7766   struct c_label_context_vm *nstack;
7767   struct c_label_list *glist;
7768
7769   gcc_assert (scope > 0);
7770
7771   /* At file_scope, we don't have to do any processing.  */
7772   if (label_context_stack_vm == NULL)
7773     return;
7774
7775   if (c_switch_stack && !c_switch_stack->blocked_vm)
7776     c_switch_stack->blocked_vm = scope;
7777   for (glist = label_context_stack_vm->labels_used;
7778        glist != NULL;
7779        glist = glist->next)
7780     {
7781       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7782     }
7783   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7784   nstack->labels_def = NULL;
7785   nstack->labels_used = NULL;
7786   nstack->scope = scope;
7787   nstack->next = label_context_stack_vm;
7788   label_context_stack_vm = nstack;
7789 }
7790
7791 /* End a scope which may contain identifiers of variably modified
7792    type, scope number SCOPE.  */
7793
7794 void
7795 c_end_vm_scope (unsigned int scope)
7796 {
7797   if (label_context_stack_vm == NULL)
7798     return;
7799   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7800     c_switch_stack->blocked_vm = 0;
7801   /* We may have a number of nested scopes of identifiers with
7802      variably modified type, all at this depth.  Pop each in turn.  */
7803   while (label_context_stack_vm->scope == scope)
7804     {
7805       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7806
7807       /* It is no longer possible to jump to labels defined within this
7808          scope.  */
7809       for (dlist = label_context_stack_vm->labels_def;
7810            dlist != NULL;
7811            dlist = dlist->next)
7812         {
7813           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7814         }
7815       /* It is again possible to define labels with a goto just outside
7816          this scope.  */
7817       for (glist = label_context_stack_vm->next->labels_used;
7818            glist != NULL;
7819            glist = glist->next)
7820         {
7821           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7822           glist_prev = glist;
7823         }
7824       if (glist_prev != NULL)
7825         glist_prev->next = label_context_stack_vm->labels_used;
7826       else
7827         label_context_stack_vm->next->labels_used
7828           = label_context_stack_vm->labels_used;
7829       label_context_stack_vm = label_context_stack_vm->next;
7830     }
7831 }
7832 \f
7833 /* Begin and end compound statements.  This is as simple as pushing
7834    and popping new statement lists from the tree.  */
7835
7836 tree
7837 c_begin_compound_stmt (bool do_scope)
7838 {
7839   tree stmt = push_stmt_list ();
7840   if (do_scope)
7841     push_scope ();
7842   return stmt;
7843 }
7844
7845 tree
7846 c_end_compound_stmt (tree stmt, bool do_scope)
7847 {
7848   tree block = NULL;
7849
7850   if (do_scope)
7851     {
7852       if (c_dialect_objc ())
7853         objc_clear_super_receiver ();
7854       block = pop_scope ();
7855     }
7856
7857   stmt = pop_stmt_list (stmt);
7858   stmt = c_build_bind_expr (block, stmt);
7859
7860   /* If this compound statement is nested immediately inside a statement
7861      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7862      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7863      STATEMENT_LISTs merge, and thus we can lose track of what statement
7864      was really last.  */
7865   if (cur_stmt_list
7866       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7867       && TREE_CODE (stmt) != BIND_EXPR)
7868     {
7869       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7870       TREE_SIDE_EFFECTS (stmt) = 1;
7871     }
7872
7873   return stmt;
7874 }
7875
7876 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7877    when the current scope is exited.  EH_ONLY is true when this is not
7878    meant to apply to normal control flow transfer.  */
7879
7880 void
7881 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7882 {
7883   enum tree_code code;
7884   tree stmt, list;
7885   bool stmt_expr;
7886
7887   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7888   stmt = build_stmt (code, NULL, cleanup);
7889   add_stmt (stmt);
7890   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7891   list = push_stmt_list ();
7892   TREE_OPERAND (stmt, 0) = list;
7893   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7894 }
7895 \f
7896 /* Build a binary-operation expression without default conversions.
7897    CODE is the kind of expression to build.
7898    This function differs from `build' in several ways:
7899    the data type of the result is computed and recorded in it,
7900    warnings are generated if arg data types are invalid,
7901    special handling for addition and subtraction of pointers is known,
7902    and some optimization is done (operations on narrow ints
7903    are done in the narrower type when that gives the same result).
7904    Constant folding is also done before the result is returned.
7905
7906    Note that the operands will never have enumeral types, or function
7907    or array types, because either they will have the default conversions
7908    performed or they have both just been converted to some other type in which
7909    the arithmetic is to be done.  */
7910
7911 tree
7912 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7913                  int convert_p)
7914 {
7915   tree type0, type1;
7916   enum tree_code code0, code1;
7917   tree op0, op1;
7918   const char *invalid_op_diag;
7919
7920   /* Expression code to give to the expression when it is built.
7921      Normally this is CODE, which is what the caller asked for,
7922      but in some special cases we change it.  */
7923   enum tree_code resultcode = code;
7924
7925   /* Data type in which the computation is to be performed.
7926      In the simplest cases this is the common type of the arguments.  */
7927   tree result_type = NULL;
7928
7929   /* Nonzero means operands have already been type-converted
7930      in whatever way is necessary.
7931      Zero means they need to be converted to RESULT_TYPE.  */
7932   int converted = 0;
7933
7934   /* Nonzero means create the expression with this type, rather than
7935      RESULT_TYPE.  */
7936   tree build_type = 0;
7937
7938   /* Nonzero means after finally constructing the expression
7939      convert it to this type.  */
7940   tree final_type = 0;
7941
7942   /* Nonzero if this is an operation like MIN or MAX which can
7943      safely be computed in short if both args are promoted shorts.
7944      Also implies COMMON.
7945      -1 indicates a bitwise operation; this makes a difference
7946      in the exact conditions for when it is safe to do the operation
7947      in a narrower mode.  */
7948   int shorten = 0;
7949
7950   /* Nonzero if this is a comparison operation;
7951      if both args are promoted shorts, compare the original shorts.
7952      Also implies COMMON.  */
7953   int short_compare = 0;
7954
7955   /* Nonzero if this is a right-shift operation, which can be computed on the
7956      original short and then promoted if the operand is a promoted short.  */
7957   int short_shift = 0;
7958
7959   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7960   int common = 0;
7961
7962   /* True means types are compatible as far as ObjC is concerned.  */
7963   bool objc_ok;
7964
7965   if (convert_p)
7966     {
7967       op0 = default_conversion (orig_op0);
7968       op1 = default_conversion (orig_op1);
7969     }
7970   else
7971     {
7972       op0 = orig_op0;
7973       op1 = orig_op1;
7974     }
7975
7976   type0 = TREE_TYPE (op0);
7977   type1 = TREE_TYPE (op1);
7978
7979   /* The expression codes of the data types of the arguments tell us
7980      whether the arguments are integers, floating, pointers, etc.  */
7981   code0 = TREE_CODE (type0);
7982   code1 = TREE_CODE (type1);
7983
7984   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7985   STRIP_TYPE_NOPS (op0);
7986   STRIP_TYPE_NOPS (op1);
7987
7988   /* If an error was already reported for one of the arguments,
7989      avoid reporting another error.  */
7990
7991   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7992     return error_mark_node;
7993
7994   if ((invalid_op_diag
7995        = targetm.invalid_binary_op (code, type0, type1)))
7996     {
7997       error (invalid_op_diag);
7998       return error_mark_node;
7999     }
8000
8001   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8002
8003   switch (code)
8004     {
8005     case PLUS_EXPR:
8006       /* Handle the pointer + int case.  */
8007       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8008         return pointer_int_sum (PLUS_EXPR, op0, op1);
8009       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8010         return pointer_int_sum (PLUS_EXPR, op1, op0);
8011       else
8012         common = 1;
8013       break;
8014
8015     case MINUS_EXPR:
8016       /* Subtraction of two similar pointers.
8017          We must subtract them as integers, then divide by object size.  */
8018       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8019           && comp_target_types (type0, type1))
8020         return pointer_diff (op0, op1);
8021       /* Handle pointer minus int.  Just like pointer plus int.  */
8022       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8023         return pointer_int_sum (MINUS_EXPR, op0, op1);
8024       else
8025         common = 1;
8026       break;
8027
8028     case MULT_EXPR:
8029       common = 1;
8030       break;
8031
8032     case TRUNC_DIV_EXPR:
8033     case CEIL_DIV_EXPR:
8034     case FLOOR_DIV_EXPR:
8035     case ROUND_DIV_EXPR:
8036     case EXACT_DIV_EXPR:
8037       warn_for_div_by_zero (op1);
8038
8039       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8040            || code0 == FIXED_POINT_TYPE
8041            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8042           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8043               || code1 == FIXED_POINT_TYPE
8044               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8045         {
8046           enum tree_code tcode0 = code0, tcode1 = code1;
8047
8048           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8049             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8050           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8051             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8052
8053           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8054               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8055             resultcode = RDIV_EXPR;
8056           else
8057             /* Although it would be tempting to shorten always here, that
8058                loses on some targets, since the modulo instruction is
8059                undefined if the quotient can't be represented in the
8060                computation mode.  We shorten only if unsigned or if
8061                dividing by something we know != -1.  */
8062             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8063                        || (TREE_CODE (op1) == INTEGER_CST
8064                            && !integer_all_onesp (op1)));
8065           common = 1;
8066         }
8067       break;
8068
8069     case BIT_AND_EXPR:
8070     case BIT_IOR_EXPR:
8071     case BIT_XOR_EXPR:
8072       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8073         shorten = -1;
8074       /* Allow vector types which are not floating point types.   */
8075       else if (code0 == VECTOR_TYPE
8076                && code1 == VECTOR_TYPE
8077                && !VECTOR_FLOAT_TYPE_P (type0)
8078                && !VECTOR_FLOAT_TYPE_P (type1))
8079         common = 1;
8080       break;
8081
8082     case TRUNC_MOD_EXPR:
8083     case FLOOR_MOD_EXPR:
8084       warn_for_div_by_zero (op1);
8085
8086       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8087         {
8088           /* Although it would be tempting to shorten always here, that loses
8089              on some targets, since the modulo instruction is undefined if the
8090              quotient can't be represented in the computation mode.  We shorten
8091              only if unsigned or if dividing by something we know != -1.  */
8092           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8093                      || (TREE_CODE (op1) == INTEGER_CST
8094                          && !integer_all_onesp (op1)));
8095           common = 1;
8096         }
8097       break;
8098
8099     case TRUTH_ANDIF_EXPR:
8100     case TRUTH_ORIF_EXPR:
8101     case TRUTH_AND_EXPR:
8102     case TRUTH_OR_EXPR:
8103     case TRUTH_XOR_EXPR:
8104       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8105            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8106            || code0 == FIXED_POINT_TYPE)
8107           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8108               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8109               || code1 == FIXED_POINT_TYPE))
8110         {
8111           /* Result of these operations is always an int,
8112              but that does not mean the operands should be
8113              converted to ints!  */
8114           result_type = integer_type_node;
8115           op0 = c_common_truthvalue_conversion (op0);
8116           op1 = c_common_truthvalue_conversion (op1);
8117           converted = 1;
8118         }
8119       break;
8120
8121       /* Shift operations: result has same type as first operand;
8122          always convert second operand to int.
8123          Also set SHORT_SHIFT if shifting rightward.  */
8124
8125     case RSHIFT_EXPR:
8126       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8127           && code1 == INTEGER_TYPE)
8128         {
8129           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8130             {
8131               if (tree_int_cst_sgn (op1) < 0)
8132                 warning (0, "right shift count is negative");
8133               else
8134                 {
8135                   if (!integer_zerop (op1))
8136                     short_shift = 1;
8137
8138                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8139                     warning (0, "right shift count >= width of type");
8140                 }
8141             }
8142
8143           /* Use the type of the value to be shifted.  */
8144           result_type = type0;
8145           /* Convert the shift-count to an integer, regardless of size
8146              of value being shifted.  */
8147           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8148             op1 = convert (integer_type_node, op1);
8149           /* Avoid converting op1 to result_type later.  */
8150           converted = 1;
8151         }
8152       break;
8153
8154     case LSHIFT_EXPR:
8155       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8156           && code1 == INTEGER_TYPE)
8157         {
8158           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8159             {
8160               if (tree_int_cst_sgn (op1) < 0)
8161                 warning (0, "left shift count is negative");
8162
8163               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8164                 warning (0, "left shift count >= width of type");
8165             }
8166
8167           /* Use the type of the value to be shifted.  */
8168           result_type = type0;
8169           /* Convert the shift-count to an integer, regardless of size
8170              of value being shifted.  */
8171           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8172             op1 = convert (integer_type_node, op1);
8173           /* Avoid converting op1 to result_type later.  */
8174           converted = 1;
8175         }
8176       break;
8177
8178     case EQ_EXPR:
8179     case NE_EXPR:
8180       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8181         warning (OPT_Wfloat_equal,
8182                  "comparing floating point with == or != is unsafe");
8183       /* Result of comparison is always int,
8184          but don't convert the args to int!  */
8185       build_type = integer_type_node;
8186       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8187            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8188           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8189               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8190         short_compare = 1;
8191       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8192         {
8193           tree tt0 = TREE_TYPE (type0);
8194           tree tt1 = TREE_TYPE (type1);
8195           /* Anything compares with void *.  void * compares with anything.
8196              Otherwise, the targets must be compatible
8197              and both must be object or both incomplete.  */
8198           if (comp_target_types (type0, type1))
8199             result_type = common_pointer_type (type0, type1);
8200           else if (VOID_TYPE_P (tt0))
8201             {
8202               /* op0 != orig_op0 detects the case of something
8203                  whose value is 0 but which isn't a valid null ptr const.  */
8204               if (pedantic && !null_pointer_constant_p (orig_op0)
8205                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8206                 pedwarn (input_location, OPT_pedantic, "ISO C forbids "
8207                          "comparison of %<void *%> with function pointer");
8208             }
8209           else if (VOID_TYPE_P (tt1))
8210             {
8211               if (pedantic && !null_pointer_constant_p (orig_op1)
8212                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8213                 pedwarn (input_location, OPT_pedantic, "ISO C forbids "
8214                          "comparison of %<void *%> with function pointer");
8215             }
8216           else
8217             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8218             if (!objc_ok)
8219               pedwarn (input_location, 0,
8220                        "comparison of distinct pointer types lacks a cast");
8221
8222           if (result_type == NULL_TREE)
8223             result_type = ptr_type_node;
8224         }
8225       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8226         {
8227           if (TREE_CODE (op0) == ADDR_EXPR
8228               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8229             warning (OPT_Waddress, "the address of %qD will never be NULL",
8230                      TREE_OPERAND (op0, 0));
8231           result_type = type0;
8232         }
8233       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8234         {
8235           if (TREE_CODE (op1) == ADDR_EXPR
8236               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8237             warning (OPT_Waddress, "the address of %qD will never be NULL",
8238                      TREE_OPERAND (op1, 0));
8239           result_type = type1;
8240         }
8241       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8242         {
8243           result_type = type0;
8244           pedwarn (input_location, 0, "comparison between pointer and integer");
8245         }
8246       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8247         {
8248           result_type = type1;
8249           pedwarn (input_location, 0, "comparison between pointer and integer");
8250         }
8251       break;
8252
8253     case LE_EXPR:
8254     case GE_EXPR:
8255     case LT_EXPR:
8256     case GT_EXPR:
8257       build_type = integer_type_node;
8258       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8259            || code0 == FIXED_POINT_TYPE)
8260           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8261               || code1 == FIXED_POINT_TYPE))
8262         short_compare = 1;
8263       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8264         {
8265           if (comp_target_types (type0, type1))
8266             {
8267               result_type = common_pointer_type (type0, type1);
8268               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8269                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8270                 pedwarn (input_location, 0,
8271                          "comparison of complete and incomplete pointers");
8272               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8273                 pedwarn (input_location, OPT_pedantic, "ISO C forbids "
8274                          "ordered comparisons of pointers to functions");
8275             }
8276           else
8277             {
8278               result_type = ptr_type_node;
8279               pedwarn (input_location, 0,
8280                        "comparison of distinct pointer types lacks a cast");
8281             }
8282         }
8283       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8284         {
8285           result_type = type0;
8286           if (pedantic)
8287             pedwarn (input_location, OPT_pedantic,
8288                      "ordered comparison of pointer with integer zero");
8289           else if (extra_warnings)
8290             warning (OPT_Wextra,
8291                      "ordered comparison of pointer with integer zero");
8292         }
8293       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8294         {
8295           result_type = type1;
8296           pedwarn (input_location, OPT_pedantic,
8297                    "ordered comparison of pointer with integer zero");
8298         }
8299       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8300         {
8301           result_type = type0;
8302           pedwarn (input_location, 0, "comparison between pointer and integer");
8303         }
8304       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8305         {
8306           result_type = type1;
8307           pedwarn (input_location, 0, "comparison between pointer and integer");
8308         }
8309       break;
8310
8311     default:
8312       gcc_unreachable ();
8313     }
8314
8315   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8316     return error_mark_node;
8317
8318   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8319       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8320           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8321                                                     TREE_TYPE (type1))))
8322     {
8323       binary_op_error (code, type0, type1);
8324       return error_mark_node;
8325     }
8326
8327   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8328        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8329       &&
8330       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8331        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8332     {
8333       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8334
8335       if (shorten || common || short_compare)
8336         {
8337           result_type = c_common_type (type0, type1);
8338           if (result_type == error_mark_node)
8339             return error_mark_node;
8340         }
8341
8342       /* For certain operations (which identify themselves by shorten != 0)
8343          if both args were extended from the same smaller type,
8344          do the arithmetic in that type and then extend.
8345
8346          shorten !=0 and !=1 indicates a bitwise operation.
8347          For them, this optimization is safe only if
8348          both args are zero-extended or both are sign-extended.
8349          Otherwise, we might change the result.
8350          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8351          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8352
8353       if (shorten && none_complex)
8354         {
8355           final_type = result_type;
8356           result_type = shorten_binary_op (result_type, op0, op1,
8357                                            shorten == -1);
8358         }
8359
8360       /* Shifts can be shortened if shifting right.  */
8361
8362       if (short_shift)
8363         {
8364           int unsigned_arg;
8365           tree arg0 = get_narrower (op0, &unsigned_arg);
8366
8367           final_type = result_type;
8368
8369           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8370             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8371
8372           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8373               /* We can shorten only if the shift count is less than the
8374                  number of bits in the smaller type size.  */
8375               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8376               /* We cannot drop an unsigned shift after sign-extension.  */
8377               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8378             {
8379               /* Do an unsigned shift if the operand was zero-extended.  */
8380               result_type
8381                 = c_common_signed_or_unsigned_type (unsigned_arg,
8382                                                     TREE_TYPE (arg0));
8383               /* Convert value-to-be-shifted to that type.  */
8384               if (TREE_TYPE (op0) != result_type)
8385                 op0 = convert (result_type, op0);
8386               converted = 1;
8387             }
8388         }
8389
8390       /* Comparison operations are shortened too but differently.
8391          They identify themselves by setting short_compare = 1.  */
8392
8393       if (short_compare)
8394         {
8395           /* Don't write &op0, etc., because that would prevent op0
8396              from being kept in a register.
8397              Instead, make copies of the our local variables and
8398              pass the copies by reference, then copy them back afterward.  */
8399           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8400           enum tree_code xresultcode = resultcode;
8401           tree val
8402             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8403
8404           if (val != 0)
8405             return val;
8406
8407           op0 = xop0, op1 = xop1;
8408           converted = 1;
8409           resultcode = xresultcode;
8410
8411           if (warn_sign_compare && !skip_evaluation)
8412             {
8413               warn_for_sign_compare (orig_op0, orig_op1, op0, op1,
8414                                      result_type, resultcode);
8415             }
8416         }
8417     }
8418
8419   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8420      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8421      Then the expression will be built.
8422      It will be given type FINAL_TYPE if that is nonzero;
8423      otherwise, it will be given type RESULT_TYPE.  */
8424
8425   if (!result_type)
8426     {
8427       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8428       return error_mark_node;
8429     }
8430
8431   if (!converted)
8432     {
8433       if (TREE_TYPE (op0) != result_type)
8434         op0 = convert_and_check (result_type, op0);
8435       if (TREE_TYPE (op1) != result_type)
8436         op1 = convert_and_check (result_type, op1);
8437
8438       /* This can happen if one operand has a vector type, and the other
8439          has a different type.  */
8440       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8441         return error_mark_node;
8442     }
8443
8444   if (build_type == NULL_TREE)
8445     build_type = result_type;
8446
8447   {
8448     /* Treat expressions in initializers specially as they can't trap.  */
8449     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8450                                                                     build_type,
8451                                                                     op0, op1)
8452                                          : fold_build2 (resultcode, build_type,
8453                                                         op0, op1);
8454
8455     if (final_type != 0)
8456       result = convert (final_type, result);
8457     return result;
8458   }
8459 }
8460
8461
8462 /* Convert EXPR to be a truth-value, validating its type for this
8463    purpose.  */
8464
8465 tree
8466 c_objc_common_truthvalue_conversion (tree expr)
8467 {
8468   switch (TREE_CODE (TREE_TYPE (expr)))
8469     {
8470     case ARRAY_TYPE:
8471       error ("used array that cannot be converted to pointer where scalar is required");
8472       return error_mark_node;
8473
8474     case RECORD_TYPE:
8475       error ("used struct type value where scalar is required");
8476       return error_mark_node;
8477
8478     case UNION_TYPE:
8479       error ("used union type value where scalar is required");
8480       return error_mark_node;
8481
8482     case FUNCTION_TYPE:
8483       gcc_unreachable ();
8484
8485     default:
8486       break;
8487     }
8488
8489   /* ??? Should we also give an error for void and vectors rather than
8490      leaving those to give errors later?  */
8491   return c_common_truthvalue_conversion (expr);
8492 }
8493 \f
8494
8495 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8496    required.  */
8497
8498 tree
8499 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8500 {
8501   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8502     {
8503       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8504       /* Executing a compound literal inside a function reinitializes
8505          it.  */
8506       if (!TREE_STATIC (decl))
8507         *se = true;
8508       return decl;
8509     }
8510   else
8511     return expr;
8512 }
8513 \f
8514 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8515
8516 tree
8517 c_begin_omp_parallel (void)
8518 {
8519   tree block;
8520
8521   keep_next_level ();
8522   block = c_begin_compound_stmt (true);
8523
8524   return block;
8525 }
8526
8527 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8528
8529 tree
8530 c_finish_omp_parallel (tree clauses, tree block)
8531 {
8532   tree stmt;
8533
8534   block = c_end_compound_stmt (block, true);
8535
8536   stmt = make_node (OMP_PARALLEL);
8537   TREE_TYPE (stmt) = void_type_node;
8538   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8539   OMP_PARALLEL_BODY (stmt) = block;
8540
8541   return add_stmt (stmt);
8542 }
8543
8544 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8545
8546 tree
8547 c_begin_omp_task (void)
8548 {
8549   tree block;
8550
8551   keep_next_level ();
8552   block = c_begin_compound_stmt (true);
8553
8554   return block;
8555 }
8556
8557 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8558
8559 tree
8560 c_finish_omp_task (tree clauses, tree block)
8561 {
8562   tree stmt;
8563
8564   block = c_end_compound_stmt (block, true);
8565
8566   stmt = make_node (OMP_TASK);
8567   TREE_TYPE (stmt) = void_type_node;
8568   OMP_TASK_CLAUSES (stmt) = clauses;
8569   OMP_TASK_BODY (stmt) = block;
8570
8571   return add_stmt (stmt);
8572 }
8573
8574 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8575    Remove any elements from the list that are invalid.  */
8576
8577 tree
8578 c_finish_omp_clauses (tree clauses)
8579 {
8580   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8581   tree c, t, *pc = &clauses;
8582   const char *name;
8583
8584   bitmap_obstack_initialize (NULL);
8585   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8586   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8587   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8588
8589   for (pc = &clauses, c = clauses; c ; c = *pc)
8590     {
8591       bool remove = false;
8592       bool need_complete = false;
8593       bool need_implicitly_determined = false;
8594
8595       switch (OMP_CLAUSE_CODE (c))
8596         {
8597         case OMP_CLAUSE_SHARED:
8598           name = "shared";
8599           need_implicitly_determined = true;
8600           goto check_dup_generic;
8601
8602         case OMP_CLAUSE_PRIVATE:
8603           name = "private";
8604           need_complete = true;
8605           need_implicitly_determined = true;
8606           goto check_dup_generic;
8607
8608         case OMP_CLAUSE_REDUCTION:
8609           name = "reduction";
8610           need_implicitly_determined = true;
8611           t = OMP_CLAUSE_DECL (c);
8612           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8613               || POINTER_TYPE_P (TREE_TYPE (t)))
8614             {
8615               error ("%qE has invalid type for %<reduction%>", t);
8616               remove = true;
8617             }
8618           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8619             {
8620               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8621               const char *r_name = NULL;
8622
8623               switch (r_code)
8624                 {
8625                 case PLUS_EXPR:
8626                 case MULT_EXPR:
8627                 case MINUS_EXPR:
8628                   break;
8629                 case BIT_AND_EXPR:
8630                   r_name = "&";
8631                   break;
8632                 case BIT_XOR_EXPR:
8633                   r_name = "^";
8634                   break;
8635                 case BIT_IOR_EXPR:
8636                   r_name = "|";
8637                   break;
8638                 case TRUTH_ANDIF_EXPR:
8639                   r_name = "&&";
8640                   break;
8641                 case TRUTH_ORIF_EXPR:
8642                   r_name = "||";
8643                   break;
8644                 default:
8645                   gcc_unreachable ();
8646                 }
8647               if (r_name)
8648                 {
8649                   error ("%qE has invalid type for %<reduction(%s)%>",
8650                          t, r_name);
8651                   remove = true;
8652                 }
8653             }
8654           goto check_dup_generic;
8655
8656         case OMP_CLAUSE_COPYPRIVATE:
8657           name = "copyprivate";
8658           goto check_dup_generic;
8659
8660         case OMP_CLAUSE_COPYIN:
8661           name = "copyin";
8662           t = OMP_CLAUSE_DECL (c);
8663           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8664             {
8665               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8666               remove = true;
8667             }
8668           goto check_dup_generic;
8669
8670         check_dup_generic:
8671           t = OMP_CLAUSE_DECL (c);
8672           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8673             {
8674               error ("%qE is not a variable in clause %qs", t, name);
8675               remove = true;
8676             }
8677           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8678                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8679                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8680             {
8681               error ("%qE appears more than once in data clauses", t);
8682               remove = true;
8683             }
8684           else
8685             bitmap_set_bit (&generic_head, DECL_UID (t));
8686           break;
8687
8688         case OMP_CLAUSE_FIRSTPRIVATE:
8689           name = "firstprivate";
8690           t = OMP_CLAUSE_DECL (c);
8691           need_complete = true;
8692           need_implicitly_determined = true;
8693           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8694             {
8695               error ("%qE is not a variable in clause %<firstprivate%>", t);
8696               remove = true;
8697             }
8698           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8699                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8700             {
8701               error ("%qE appears more than once in data clauses", t);
8702               remove = true;
8703             }
8704           else
8705             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8706           break;
8707
8708         case OMP_CLAUSE_LASTPRIVATE:
8709           name = "lastprivate";
8710           t = OMP_CLAUSE_DECL (c);
8711           need_complete = true;
8712           need_implicitly_determined = true;
8713           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8714             {
8715               error ("%qE is not a variable in clause %<lastprivate%>", t);
8716               remove = true;
8717             }
8718           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8719                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8720             {
8721               error ("%qE appears more than once in data clauses", t);
8722               remove = true;
8723             }
8724           else
8725             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8726           break;
8727
8728         case OMP_CLAUSE_IF:
8729         case OMP_CLAUSE_NUM_THREADS:
8730         case OMP_CLAUSE_SCHEDULE:
8731         case OMP_CLAUSE_NOWAIT:
8732         case OMP_CLAUSE_ORDERED:
8733         case OMP_CLAUSE_DEFAULT:
8734         case OMP_CLAUSE_UNTIED:
8735         case OMP_CLAUSE_COLLAPSE:
8736           pc = &OMP_CLAUSE_CHAIN (c);
8737           continue;
8738
8739         default:
8740           gcc_unreachable ();
8741         }
8742
8743       if (!remove)
8744         {
8745           t = OMP_CLAUSE_DECL (c);
8746
8747           if (need_complete)
8748             {
8749               t = require_complete_type (t);
8750               if (t == error_mark_node)
8751                 remove = true;
8752             }
8753
8754           if (need_implicitly_determined)
8755             {
8756               const char *share_name = NULL;
8757
8758               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8759                 share_name = "threadprivate";
8760               else switch (c_omp_predetermined_sharing (t))
8761                 {
8762                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8763                   break;
8764                 case OMP_CLAUSE_DEFAULT_SHARED:
8765                   share_name = "shared";
8766                   break;
8767                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8768                   share_name = "private";
8769                   break;
8770                 default:
8771                   gcc_unreachable ();
8772                 }
8773               if (share_name)
8774                 {
8775                   error ("%qE is predetermined %qs for %qs",
8776                          t, share_name, name);
8777                   remove = true;
8778                 }
8779             }
8780         }
8781
8782       if (remove)
8783         *pc = OMP_CLAUSE_CHAIN (c);
8784       else
8785         pc = &OMP_CLAUSE_CHAIN (c);
8786     }
8787
8788   bitmap_obstack_release (NULL);
8789   return clauses;
8790 }
8791
8792 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8793    down to the element type of an array.  */
8794
8795 tree
8796 c_build_qualified_type (tree type, int type_quals)
8797 {
8798   if (type == error_mark_node)
8799     return type;
8800
8801   if (TREE_CODE (type) == ARRAY_TYPE)
8802     {
8803       tree t;
8804       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8805                                                   type_quals);
8806
8807       /* See if we already have an identically qualified type.  */
8808       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8809         {
8810           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8811               && TYPE_NAME (t) == TYPE_NAME (type)
8812               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8813               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8814                                        TYPE_ATTRIBUTES (type)))
8815             break;
8816         }
8817       if (!t)
8818         {
8819           tree domain = TYPE_DOMAIN (type);
8820
8821           t = build_variant_type_copy (type);
8822           TREE_TYPE (t) = element_type;
8823
8824           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8825               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8826             SET_TYPE_STRUCTURAL_EQUALITY (t);
8827           else if (TYPE_CANONICAL (element_type) != element_type
8828                    || (domain && TYPE_CANONICAL (domain) != domain))
8829             {
8830               tree unqualified_canon
8831                 = build_array_type (TYPE_CANONICAL (element_type),
8832                                     domain? TYPE_CANONICAL (domain)
8833                                           : NULL_TREE);
8834               TYPE_CANONICAL (t)
8835                 = c_build_qualified_type (unqualified_canon, type_quals);
8836             }
8837           else
8838             TYPE_CANONICAL (t) = t;
8839         }
8840       return t;
8841     }
8842
8843   /* A restrict-qualified pointer type must be a pointer to object or
8844      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8845      REFERENCE_TYPEs, which is appropriate for C++.  */
8846   if ((type_quals & TYPE_QUAL_RESTRICT)
8847       && (!POINTER_TYPE_P (type)
8848           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8849     {
8850       error ("invalid use of %<restrict%>");
8851       type_quals &= ~TYPE_QUAL_RESTRICT;
8852     }
8853
8854   return build_qualified_type (type, type_quals);
8855 }