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    LOC is the location to use for the generated tree.  */
1973
1974 tree
1975 build_indirect_ref (tree ptr, const char *errorstring, location_t loc)
1976 {
1977   tree pointer = default_conversion (ptr);
1978   tree type = TREE_TYPE (pointer);
1979   tree ref;
1980
1981   if (TREE_CODE (type) == POINTER_TYPE)
1982     {
1983       if (CONVERT_EXPR_P (pointer)
1984           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1985         {
1986           /* If a warning is issued, mark it to avoid duplicates from
1987              the backend.  This only needs to be done at
1988              warn_strict_aliasing > 2.  */
1989           if (warn_strict_aliasing > 2)
1990             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1991                                          type, TREE_OPERAND (pointer, 0)))
1992               TREE_NO_WARNING (pointer) = 1;
1993         }
1994
1995       if (TREE_CODE (pointer) == ADDR_EXPR
1996           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1997               == TREE_TYPE (type)))
1998         {
1999           ref = TREE_OPERAND (pointer, 0);
2000           protected_set_expr_location (ref, loc);
2001           return ref;
2002         }
2003       else
2004         {
2005           tree t = TREE_TYPE (type);
2006
2007           ref = build1 (INDIRECT_REF, t, pointer);
2008
2009           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2010             {
2011               error ("dereferencing pointer to incomplete type");
2012               return error_mark_node;
2013             }
2014           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2015             warning (0, "dereferencing %<void *%> pointer");
2016
2017           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2018              so that we get the proper error message if the result is used
2019              to assign to.  Also, &* is supposed to be a no-op.
2020              And ANSI C seems to specify that the type of the result
2021              should be the const type.  */
2022           /* A de-reference of a pointer to const is not a const.  It is valid
2023              to change it via some other pointer.  */
2024           TREE_READONLY (ref) = TYPE_READONLY (t);
2025           TREE_SIDE_EFFECTS (ref)
2026             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2027           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2028           protected_set_expr_location (ref, loc);
2029           return ref;
2030         }
2031     }
2032   else if (TREE_CODE (pointer) != ERROR_MARK)
2033     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2034   return error_mark_node;
2035 }
2036
2037 /* This handles expressions of the form "a[i]", which denotes
2038    an array reference.
2039
2040    This is logically equivalent in C to *(a+i), but we may do it differently.
2041    If A is a variable or a member, we generate a primitive ARRAY_REF.
2042    This avoids forcing the array out of registers, and can work on
2043    arrays that are not lvalues (for example, members of structures returned
2044    by functions).
2045
2046    LOC is the location to use for the returned expression.  */
2047
2048 tree
2049 build_array_ref (tree array, tree index, location_t loc)
2050 {
2051   tree ret;
2052   bool swapped = false;
2053   if (TREE_TYPE (array) == error_mark_node
2054       || TREE_TYPE (index) == error_mark_node)
2055     return error_mark_node;
2056
2057   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2058       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2059     {
2060       tree temp;
2061       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2062           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2063         {
2064           error_at (loc, "subscripted value is neither array nor pointer");
2065           return error_mark_node;
2066         }
2067       temp = array;
2068       array = index;
2069       index = temp;
2070       swapped = true;
2071     }
2072
2073   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2074     {
2075       error_at (loc, "array subscript is not an integer");
2076       return error_mark_node;
2077     }
2078
2079   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2080     {
2081       error_at (loc, "subscripted value is pointer to function");
2082       return error_mark_node;
2083     }
2084
2085   /* ??? Existing practice has been to warn only when the char
2086      index is syntactically the index, not for char[array].  */
2087   if (!swapped)
2088      warn_array_subscript_with_type_char (index);
2089
2090   /* Apply default promotions *after* noticing character types.  */
2091   index = default_conversion (index);
2092
2093   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2094
2095   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2096     {
2097       tree rval, type;
2098
2099       /* An array that is indexed by a non-constant
2100          cannot be stored in a register; we must be able to do
2101          address arithmetic on its address.
2102          Likewise an array of elements of variable size.  */
2103       if (TREE_CODE (index) != INTEGER_CST
2104           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2105               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2106         {
2107           if (!c_mark_addressable (array))
2108             return error_mark_node;
2109         }
2110       /* An array that is indexed by a constant value which is not within
2111          the array bounds cannot be stored in a register either; because we
2112          would get a crash in store_bit_field/extract_bit_field when trying
2113          to access a non-existent part of the register.  */
2114       if (TREE_CODE (index) == INTEGER_CST
2115           && TYPE_DOMAIN (TREE_TYPE (array))
2116           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2117         {
2118           if (!c_mark_addressable (array))
2119             return error_mark_node;
2120         }
2121
2122       if (pedantic)
2123         {
2124           tree foo = array;
2125           while (TREE_CODE (foo) == COMPONENT_REF)
2126             foo = TREE_OPERAND (foo, 0);
2127           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2128             pedwarn (loc, OPT_pedantic,
2129                      "ISO C forbids subscripting %<register%> array");
2130           else if (!flag_isoc99 && !lvalue_p (foo))
2131             pedwarn (loc, OPT_pedantic,
2132                      "ISO C90 forbids subscripting non-lvalue array");
2133         }
2134
2135       type = TREE_TYPE (TREE_TYPE (array));
2136       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2137       /* Array ref is const/volatile if the array elements are
2138          or if the array is.  */
2139       TREE_READONLY (rval)
2140         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2141             | TREE_READONLY (array));
2142       TREE_SIDE_EFFECTS (rval)
2143         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2144             | TREE_SIDE_EFFECTS (array));
2145       TREE_THIS_VOLATILE (rval)
2146         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2147             /* This was added by rms on 16 Nov 91.
2148                It fixes  vol struct foo *a;  a->elts[1]
2149                in an inline function.
2150                Hope it doesn't break something else.  */
2151             | TREE_THIS_VOLATILE (array));
2152       ret = require_complete_type (fold (rval));
2153       protected_set_expr_location (ret, loc);
2154       return ret;
2155     }
2156   else
2157     {
2158       tree ar = default_conversion (array);
2159
2160       if (ar == error_mark_node)
2161         return ar;
2162
2163       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2164       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2165
2166       return build_indirect_ref
2167         (build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2168          "array indexing", loc);
2169     }
2170 }
2171 \f
2172 /* Build an external reference to identifier ID.  FUN indicates
2173    whether this will be used for a function call.  LOC is the source
2174    location of the identifier.  */
2175 tree
2176 build_external_ref (tree id, int fun, location_t loc)
2177 {
2178   tree ref;
2179   tree decl = lookup_name (id);
2180
2181   /* In Objective-C, an instance variable (ivar) may be preferred to
2182      whatever lookup_name() found.  */
2183   decl = objc_lookup_ivar (decl, id);
2184
2185   if (decl && decl != error_mark_node)
2186     ref = decl;
2187   else if (fun)
2188     /* Implicit function declaration.  */
2189     ref = implicitly_declare (id);
2190   else if (decl == error_mark_node)
2191     /* Don't complain about something that's already been
2192        complained about.  */
2193     return error_mark_node;
2194   else
2195     {
2196       undeclared_variable (id, loc);
2197       return error_mark_node;
2198     }
2199
2200   if (TREE_TYPE (ref) == error_mark_node)
2201     return error_mark_node;
2202
2203   if (TREE_DEPRECATED (ref))
2204     warn_deprecated_use (ref);
2205
2206   /* Recursive call does not count as usage.  */
2207   if (ref != current_function_decl)
2208     {
2209       TREE_USED (ref) = 1;
2210     }
2211
2212   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2213     {
2214       if (!in_sizeof && !in_typeof)
2215         C_DECL_USED (ref) = 1;
2216       else if (DECL_INITIAL (ref) == 0
2217                && DECL_EXTERNAL (ref)
2218                && !TREE_PUBLIC (ref))
2219         record_maybe_used_decl (ref);
2220     }
2221
2222   if (TREE_CODE (ref) == CONST_DECL)
2223     {
2224       used_types_insert (TREE_TYPE (ref));
2225       ref = DECL_INITIAL (ref);
2226       TREE_CONSTANT (ref) = 1;
2227     }
2228   else if (current_function_decl != 0
2229            && !DECL_FILE_SCOPE_P (current_function_decl)
2230            && (TREE_CODE (ref) == VAR_DECL
2231                || TREE_CODE (ref) == PARM_DECL
2232                || TREE_CODE (ref) == FUNCTION_DECL))
2233     {
2234       tree context = decl_function_context (ref);
2235
2236       if (context != 0 && context != current_function_decl)
2237         DECL_NONLOCAL (ref) = 1;
2238     }
2239   /* C99 6.7.4p3: An inline definition of a function with external
2240      linkage ... shall not contain a reference to an identifier with
2241      internal linkage.  */
2242   else if (current_function_decl != 0
2243            && DECL_DECLARED_INLINE_P (current_function_decl)
2244            && DECL_EXTERNAL (current_function_decl)
2245            && VAR_OR_FUNCTION_DECL_P (ref)
2246            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2247            && ! TREE_PUBLIC (ref)
2248            && DECL_CONTEXT (ref) != current_function_decl)
2249     pedwarn (loc, 0, "%qD is static but used in inline function %qD "
2250              "which is not static", ref, current_function_decl);
2251
2252   return ref;
2253 }
2254
2255 /* Record details of decls possibly used inside sizeof or typeof.  */
2256 struct maybe_used_decl
2257 {
2258   /* The decl.  */
2259   tree decl;
2260   /* The level seen at (in_sizeof + in_typeof).  */
2261   int level;
2262   /* The next one at this level or above, or NULL.  */
2263   struct maybe_used_decl *next;
2264 };
2265
2266 static struct maybe_used_decl *maybe_used_decls;
2267
2268 /* Record that DECL, an undefined static function reference seen
2269    inside sizeof or typeof, might be used if the operand of sizeof is
2270    a VLA type or the operand of typeof is a variably modified
2271    type.  */
2272
2273 static void
2274 record_maybe_used_decl (tree decl)
2275 {
2276   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2277   t->decl = decl;
2278   t->level = in_sizeof + in_typeof;
2279   t->next = maybe_used_decls;
2280   maybe_used_decls = t;
2281 }
2282
2283 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2284    USED is false, just discard them.  If it is true, mark them used
2285    (if no longer inside sizeof or typeof) or move them to the next
2286    level up (if still inside sizeof or typeof).  */
2287
2288 void
2289 pop_maybe_used (bool used)
2290 {
2291   struct maybe_used_decl *p = maybe_used_decls;
2292   int cur_level = in_sizeof + in_typeof;
2293   while (p && p->level > cur_level)
2294     {
2295       if (used)
2296         {
2297           if (cur_level == 0)
2298             C_DECL_USED (p->decl) = 1;
2299           else
2300             p->level = cur_level;
2301         }
2302       p = p->next;
2303     }
2304   if (!used || cur_level == 0)
2305     maybe_used_decls = p;
2306 }
2307
2308 /* Return the result of sizeof applied to EXPR.  */
2309
2310 struct c_expr
2311 c_expr_sizeof_expr (struct c_expr expr)
2312 {
2313   struct c_expr ret;
2314   if (expr.value == error_mark_node)
2315     {
2316       ret.value = error_mark_node;
2317       ret.original_code = ERROR_MARK;
2318       pop_maybe_used (false);
2319     }
2320   else
2321     {
2322       ret.value = c_sizeof (TREE_TYPE (expr.value));
2323       ret.original_code = ERROR_MARK;
2324       if (c_vla_type_p (TREE_TYPE (expr.value)))
2325         {
2326           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2327           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2328         }
2329       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2330     }
2331   return ret;
2332 }
2333
2334 /* Return the result of sizeof applied to T, a structure for the type
2335    name passed to sizeof (rather than the type itself).  */
2336
2337 struct c_expr
2338 c_expr_sizeof_type (struct c_type_name *t)
2339 {
2340   tree type;
2341   struct c_expr ret;
2342   type = groktypename (t);
2343   ret.value = c_sizeof (type);
2344   ret.original_code = ERROR_MARK;
2345   pop_maybe_used (type != error_mark_node
2346                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2347   return ret;
2348 }
2349
2350 /* Build a function call to function FUNCTION with parameters PARAMS.
2351    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2352    TREE_VALUE of each node is a parameter-expression.
2353    FUNCTION's data type may be a function type or a pointer-to-function.  */
2354
2355 tree
2356 build_function_call (tree function, tree params)
2357 {
2358   tree fntype, fundecl = 0;
2359   tree name = NULL_TREE, result;
2360   tree tem;
2361   int nargs;
2362   tree *argarray;
2363
2364
2365   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2366   STRIP_TYPE_NOPS (function);
2367
2368   /* Convert anything with function type to a pointer-to-function.  */
2369   if (TREE_CODE (function) == FUNCTION_DECL)
2370     {
2371       /* Implement type-directed function overloading for builtins.
2372          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2373          handle all the type checking.  The result is a complete expression
2374          that implements this function call.  */
2375       tem = resolve_overloaded_builtin (function, params);
2376       if (tem)
2377         return tem;
2378
2379       name = DECL_NAME (function);
2380       fundecl = function;
2381     }
2382   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2383     function = function_to_pointer_conversion (function);
2384
2385   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2386      expressions, like those used for ObjC messenger dispatches.  */
2387   function = objc_rewrite_function_call (function, params);
2388
2389   fntype = TREE_TYPE (function);
2390
2391   if (TREE_CODE (fntype) == ERROR_MARK)
2392     return error_mark_node;
2393
2394   if (!(TREE_CODE (fntype) == POINTER_TYPE
2395         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2396     {
2397       error ("called object %qE is not a function", function);
2398       return error_mark_node;
2399     }
2400
2401   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2402     current_function_returns_abnormally = 1;
2403
2404   /* fntype now gets the type of function pointed to.  */
2405   fntype = TREE_TYPE (fntype);
2406
2407   /* Check that the function is called through a compatible prototype.
2408      If it is not, replace the call by a trap, wrapped up in a compound
2409      expression if necessary.  This has the nice side-effect to prevent
2410      the tree-inliner from generating invalid assignment trees which may
2411      blow up in the RTL expander later.  */
2412   if (CONVERT_EXPR_P (function)
2413       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2414       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2415       && !comptypes (fntype, TREE_TYPE (tem)))
2416     {
2417       tree return_type = TREE_TYPE (fntype);
2418       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2419                                        NULL_TREE);
2420
2421       /* This situation leads to run-time undefined behavior.  We can't,
2422          therefore, simply error unless we can prove that all possible
2423          executions of the program must execute the code.  */
2424       if (warning (0, "function called through a non-compatible type"))
2425         /* We can, however, treat "undefined" any way we please.
2426            Call abort to encourage the user to fix the program.  */
2427         inform (input_location, "if this code is reached, the program will abort");
2428
2429       if (VOID_TYPE_P (return_type))
2430         return trap;
2431       else
2432         {
2433           tree rhs;
2434
2435           if (AGGREGATE_TYPE_P (return_type))
2436             rhs = build_compound_literal (return_type,
2437                                           build_constructor (return_type, 0));
2438           else
2439             rhs = fold_convert (return_type, integer_zero_node);
2440
2441           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2442         }
2443     }
2444
2445   /* Convert the parameters to the types declared in the
2446      function prototype, or apply default promotions.  */
2447
2448   nargs = list_length (params);
2449   argarray = (tree *) alloca (nargs * sizeof (tree));
2450   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2451                              params, function, fundecl);
2452   if (nargs < 0)
2453     return error_mark_node;
2454
2455   /* Check that arguments to builtin functions match the expectations.  */
2456   if (fundecl
2457       && DECL_BUILT_IN (fundecl)
2458       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2459       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2460     return error_mark_node;
2461
2462   /* Check that the arguments to the function are valid.  */
2463   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2464                             TYPE_ARG_TYPES (fntype));
2465
2466   if (require_constant_value)
2467     {
2468       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2469                                                   function, nargs, argarray);
2470       if (TREE_CONSTANT (result)
2471           && (name == NULL_TREE
2472               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2473         pedwarn_init (input_location, 0, "initializer element is not constant");
2474     }
2475   else
2476     result = fold_build_call_array (TREE_TYPE (fntype),
2477                                     function, nargs, argarray);
2478
2479   if (VOID_TYPE_P (TREE_TYPE (result)))
2480     return result;
2481   return require_complete_type (result);
2482 }
2483 \f
2484 /* Convert the argument expressions in the list VALUES
2485    to the types in the list TYPELIST.  The resulting arguments are
2486    stored in the array ARGARRAY which has size NARGS.
2487
2488    If TYPELIST is exhausted, or when an element has NULL as its type,
2489    perform the default conversions.
2490
2491    PARMLIST is the chain of parm decls for the function being called.
2492    It may be 0, if that info is not available.
2493    It is used only for generating error messages.
2494
2495    FUNCTION is a tree for the called function.  It is used only for
2496    error messages, where it is formatted with %qE.
2497
2498    This is also where warnings about wrong number of args are generated.
2499
2500    VALUES is a chain of TREE_LIST nodes with the elements of the list
2501    in the TREE_VALUE slots of those nodes.
2502
2503    Returns the actual number of arguments processed (which may be less
2504    than NARGS in some error situations), or -1 on failure.  */
2505
2506 static int
2507 convert_arguments (int nargs, tree *argarray,
2508                    tree typelist, tree values, tree function, tree fundecl)
2509 {
2510   tree typetail, valtail;
2511   int parmnum;
2512   const bool type_generic = fundecl
2513     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2514   tree selector;
2515
2516   /* Change pointer to function to the function itself for
2517      diagnostics.  */
2518   if (TREE_CODE (function) == ADDR_EXPR
2519       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2520     function = TREE_OPERAND (function, 0);
2521
2522   /* Handle an ObjC selector specially for diagnostics.  */
2523   selector = objc_message_selector ();
2524
2525   /* Scan the given expressions and types, producing individual
2526      converted arguments and storing them in ARGARRAY.  */
2527
2528   for (valtail = values, typetail = typelist, parmnum = 0;
2529        valtail;
2530        valtail = TREE_CHAIN (valtail), parmnum++)
2531     {
2532       tree type = typetail ? TREE_VALUE (typetail) : 0;
2533       tree val = TREE_VALUE (valtail);
2534       tree rname = function;
2535       int argnum = parmnum + 1;
2536       const char *invalid_func_diag;
2537
2538       if (type == void_type_node)
2539         {
2540           error ("too many arguments to function %qE", function);
2541           return parmnum;
2542         }
2543
2544       if (selector && argnum > 2)
2545         {
2546           rname = selector;
2547           argnum -= 2;
2548         }
2549
2550       STRIP_TYPE_NOPS (val);
2551
2552       val = require_complete_type (val);
2553
2554       if (type != 0)
2555         {
2556           /* Formal parm type is specified by a function prototype.  */
2557           tree parmval;
2558
2559           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2560             {
2561               error ("type of formal parameter %d is incomplete", parmnum + 1);
2562               parmval = val;
2563             }
2564           else
2565             {
2566               /* Optionally warn about conversions that
2567                  differ from the default conversions.  */
2568               if (warn_traditional_conversion || warn_traditional)
2569                 {
2570                   unsigned int formal_prec = TYPE_PRECISION (type);
2571
2572                   if (INTEGRAL_TYPE_P (type)
2573                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2574                     warning (0, "passing argument %d of %qE as integer "
2575                              "rather than floating due to prototype",
2576                              argnum, rname);
2577                   if (INTEGRAL_TYPE_P (type)
2578                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2579                     warning (0, "passing argument %d of %qE as integer "
2580                              "rather than complex due to prototype",
2581                              argnum, rname);
2582                   else if (TREE_CODE (type) == COMPLEX_TYPE
2583                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2584                     warning (0, "passing argument %d of %qE as complex "
2585                              "rather than floating due to prototype",
2586                              argnum, rname);
2587                   else if (TREE_CODE (type) == REAL_TYPE
2588                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2589                     warning (0, "passing argument %d of %qE as floating "
2590                              "rather than integer due to prototype",
2591                              argnum, rname);
2592                   else if (TREE_CODE (type) == COMPLEX_TYPE
2593                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2594                     warning (0, "passing argument %d of %qE as complex "
2595                              "rather than integer due to prototype",
2596                              argnum, rname);
2597                   else if (TREE_CODE (type) == REAL_TYPE
2598                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2599                     warning (0, "passing argument %d of %qE as floating "
2600                              "rather than complex due to prototype",
2601                              argnum, rname);
2602                   /* ??? At some point, messages should be written about
2603                      conversions between complex types, but that's too messy
2604                      to do now.  */
2605                   else if (TREE_CODE (type) == REAL_TYPE
2606                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2607                     {
2608                       /* Warn if any argument is passed as `float',
2609                          since without a prototype it would be `double'.  */
2610                       if (formal_prec == TYPE_PRECISION (float_type_node)
2611                           && type != dfloat32_type_node)
2612                         warning (0, "passing argument %d of %qE as %<float%> "
2613                                  "rather than %<double%> due to prototype",
2614                                  argnum, rname);
2615
2616                       /* Warn if mismatch between argument and prototype
2617                          for decimal float types.  Warn of conversions with
2618                          binary float types and of precision narrowing due to
2619                          prototype. */
2620                       else if (type != TREE_TYPE (val)
2621                                && (type == dfloat32_type_node
2622                                    || type == dfloat64_type_node
2623                                    || type == dfloat128_type_node
2624                                    || TREE_TYPE (val) == dfloat32_type_node
2625                                    || TREE_TYPE (val) == dfloat64_type_node
2626                                    || TREE_TYPE (val) == dfloat128_type_node)
2627                                && (formal_prec
2628                                    <= TYPE_PRECISION (TREE_TYPE (val))
2629                                    || (type == dfloat128_type_node
2630                                        && (TREE_TYPE (val)
2631                                            != dfloat64_type_node
2632                                            && (TREE_TYPE (val)
2633                                                != dfloat32_type_node)))
2634                                    || (type == dfloat64_type_node
2635                                        && (TREE_TYPE (val)
2636                                            != dfloat32_type_node))))
2637                         warning (0, "passing argument %d of %qE as %qT "
2638                                  "rather than %qT due to prototype",
2639                                  argnum, rname, type, TREE_TYPE (val));
2640
2641                     }
2642                   /* Detect integer changing in width or signedness.
2643                      These warnings are only activated with
2644                      -Wtraditional-conversion, not with -Wtraditional.  */
2645                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2646                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2647                     {
2648                       tree would_have_been = default_conversion (val);
2649                       tree type1 = TREE_TYPE (would_have_been);
2650
2651                       if (TREE_CODE (type) == ENUMERAL_TYPE
2652                           && (TYPE_MAIN_VARIANT (type)
2653                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2654                         /* No warning if function asks for enum
2655                            and the actual arg is that enum type.  */
2656                         ;
2657                       else if (formal_prec != TYPE_PRECISION (type1))
2658                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2659                                  "with different width due to prototype",
2660                                  argnum, rname);
2661                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2662                         ;
2663                       /* Don't complain if the formal parameter type
2664                          is an enum, because we can't tell now whether
2665                          the value was an enum--even the same enum.  */
2666                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2667                         ;
2668                       else if (TREE_CODE (val) == INTEGER_CST
2669                                && int_fits_type_p (val, type))
2670                         /* Change in signedness doesn't matter
2671                            if a constant value is unaffected.  */
2672                         ;
2673                       /* If the value is extended from a narrower
2674                          unsigned type, it doesn't matter whether we
2675                          pass it as signed or unsigned; the value
2676                          certainly is the same either way.  */
2677                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2678                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2679                         ;
2680                       else if (TYPE_UNSIGNED (type))
2681                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2682                                  "as unsigned due to prototype",
2683                                  argnum, rname);
2684                       else
2685                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2686                                  "as signed due to prototype", argnum, rname);
2687                     }
2688                 }
2689
2690               parmval = convert_for_assignment (type, val, ic_argpass,
2691                                                 fundecl, function,
2692                                                 parmnum + 1);
2693
2694               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2695                   && INTEGRAL_TYPE_P (type)
2696                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2697                 parmval = default_conversion (parmval);
2698             }
2699           argarray[parmnum] = parmval;
2700         }
2701       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2702                && (TYPE_PRECISION (TREE_TYPE (val))
2703                    < TYPE_PRECISION (double_type_node))
2704                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2705         {
2706           if (type_generic)
2707             argarray[parmnum] = val;
2708           else
2709             /* Convert `float' to `double'.  */
2710             argarray[parmnum] = convert (double_type_node, val);
2711         }
2712       else if ((invalid_func_diag =
2713                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2714         {
2715           error (invalid_func_diag);
2716           return -1;
2717         }
2718       else
2719         /* Convert `short' and `char' to full-size `int'.  */
2720         argarray[parmnum] = default_conversion (val);
2721
2722       if (typetail)
2723         typetail = TREE_CHAIN (typetail);
2724     }
2725
2726   gcc_assert (parmnum == nargs);
2727
2728   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2729     {
2730       error ("too few arguments to function %qE", function);
2731       return -1;
2732     }
2733
2734   return parmnum;
2735 }
2736 \f
2737 /* This is the entry point used by the parser to build unary operators
2738    in the input.  CODE, a tree_code, specifies the unary operator, and
2739    ARG is the operand.  For unary plus, the C parser currently uses
2740    CONVERT_EXPR for code.
2741
2742    LOC is the location to use for the tree generated.
2743 */
2744
2745 struct c_expr
2746 parser_build_unary_op (enum tree_code code, struct c_expr arg, location_t loc)
2747 {
2748   struct c_expr result;
2749
2750   result.original_code = ERROR_MARK;
2751   result.value = build_unary_op (code, arg.value, 0);
2752   protected_set_expr_location (result.value, loc);
2753
2754   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2755     overflow_warning (result.value);
2756
2757   return result;
2758 }
2759
2760 /* This is the entry point used by the parser to build binary operators
2761    in the input.  CODE, a tree_code, specifies the binary operator, and
2762    ARG1 and ARG2 are the operands.  In addition to constructing the
2763    expression, we check for operands that were written with other binary
2764    operators in a way that is likely to confuse the user.
2765
2766    LOCATION is the location of the binary operator.  */
2767
2768 struct c_expr
2769 parser_build_binary_op (location_t location, enum tree_code code,
2770                         struct c_expr arg1, struct c_expr arg2)
2771 {
2772   struct c_expr result;
2773
2774   enum tree_code code1 = arg1.original_code;
2775   enum tree_code code2 = arg2.original_code;
2776
2777   result.value = build_binary_op (location, code,
2778                                   arg1.value, arg2.value, 1);
2779   result.original_code = code;
2780
2781   if (TREE_CODE (result.value) == ERROR_MARK)
2782     return result;
2783
2784   if (location != UNKNOWN_LOCATION)
2785     protected_set_expr_location (result.value, location);
2786
2787   /* Check for cases such as x+y<<z which users are likely
2788      to misinterpret.  */
2789   if (warn_parentheses)
2790     warn_about_parentheses (code, code1, code2);
2791
2792   if (TREE_CODE_CLASS (code1) != tcc_comparison)
2793     warn_logical_operator (code, arg1.value, arg2.value);
2794
2795   /* Warn about comparisons against string literals, with the exception
2796      of testing for equality or inequality of a string literal with NULL.  */
2797   if (code == EQ_EXPR || code == NE_EXPR)
2798     {
2799       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2800           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2801         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2802     }
2803   else if (TREE_CODE_CLASS (code) == tcc_comparison
2804            && (code1 == STRING_CST || code2 == STRING_CST))
2805     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2806
2807   if (TREE_OVERFLOW_P (result.value)
2808       && !TREE_OVERFLOW_P (arg1.value)
2809       && !TREE_OVERFLOW_P (arg2.value))
2810     overflow_warning (result.value);
2811
2812   return result;
2813 }
2814 \f
2815 /* Return a tree for the difference of pointers OP0 and OP1.
2816    The resulting tree has type int.  */
2817
2818 static tree
2819 pointer_diff (tree op0, tree op1)
2820 {
2821   tree restype = ptrdiff_type_node;
2822
2823   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2824   tree con0, con1, lit0, lit1;
2825   tree orig_op1 = op1;
2826
2827   if (TREE_CODE (target_type) == VOID_TYPE)
2828     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2829              "pointer of type %<void *%> used in subtraction");
2830   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2831     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2832              "pointer to a function used in subtraction");
2833
2834   /* If the conversion to ptrdiff_type does anything like widening or
2835      converting a partial to an integral mode, we get a convert_expression
2836      that is in the way to do any simplifications.
2837      (fold-const.c doesn't know that the extra bits won't be needed.
2838      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2839      different mode in place.)
2840      So first try to find a common term here 'by hand'; we want to cover
2841      at least the cases that occur in legal static initializers.  */
2842   if (CONVERT_EXPR_P (op0)
2843       && (TYPE_PRECISION (TREE_TYPE (op0))
2844           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2845     con0 = TREE_OPERAND (op0, 0);
2846   else
2847     con0 = op0;
2848   if (CONVERT_EXPR_P (op1)
2849       && (TYPE_PRECISION (TREE_TYPE (op1))
2850           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2851     con1 = TREE_OPERAND (op1, 0);
2852   else
2853     con1 = op1;
2854
2855   if (TREE_CODE (con0) == PLUS_EXPR)
2856     {
2857       lit0 = TREE_OPERAND (con0, 1);
2858       con0 = TREE_OPERAND (con0, 0);
2859     }
2860   else
2861     lit0 = integer_zero_node;
2862
2863   if (TREE_CODE (con1) == PLUS_EXPR)
2864     {
2865       lit1 = TREE_OPERAND (con1, 1);
2866       con1 = TREE_OPERAND (con1, 0);
2867     }
2868   else
2869     lit1 = integer_zero_node;
2870
2871   if (operand_equal_p (con0, con1, 0))
2872     {
2873       op0 = lit0;
2874       op1 = lit1;
2875     }
2876
2877
2878   /* First do the subtraction as integers;
2879      then drop through to build the divide operator.
2880      Do not do default conversions on the minus operator
2881      in case restype is a short type.  */
2882
2883   op0 = build_binary_op (input_location,
2884                          MINUS_EXPR, convert (restype, op0),
2885                          convert (restype, op1), 0);
2886   /* This generates an error if op1 is pointer to incomplete type.  */
2887   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2888     error ("arithmetic on pointer to an incomplete type");
2889
2890   /* This generates an error if op0 is pointer to incomplete type.  */
2891   op1 = c_size_in_bytes (target_type);
2892
2893   /* Divide by the size, in easiest possible way.  */
2894   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2895 }
2896 \f
2897 /* Construct and perhaps optimize a tree representation
2898    for a unary operation.  CODE, a tree_code, specifies the operation
2899    and XARG is the operand.
2900    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2901    the default promotions (such as from short to int).
2902    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2903    allows non-lvalues; this is only used to handle conversion of non-lvalue
2904    arrays to pointers in C99.  */
2905
2906 tree
2907 build_unary_op (enum tree_code code, tree xarg, int flag)
2908 {
2909   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2910   tree arg = xarg;
2911   tree argtype = 0;
2912   enum tree_code typecode;
2913   tree val;
2914   int noconvert = flag;
2915   const char *invalid_op_diag;
2916
2917   if (code != ADDR_EXPR)
2918     arg = require_complete_type (arg);
2919
2920   typecode = TREE_CODE (TREE_TYPE (arg));
2921   if (typecode == ERROR_MARK)
2922     return error_mark_node;
2923   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2924     typecode = INTEGER_TYPE;
2925
2926   if ((invalid_op_diag
2927        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2928     {
2929       error (invalid_op_diag);
2930       return error_mark_node;
2931     }
2932
2933   switch (code)
2934     {
2935     case CONVERT_EXPR:
2936       /* This is used for unary plus, because a CONVERT_EXPR
2937          is enough to prevent anybody from looking inside for
2938          associativity, but won't generate any code.  */
2939       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2940             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2941             || typecode == VECTOR_TYPE))
2942         {
2943           error ("wrong type argument to unary plus");
2944           return error_mark_node;
2945         }
2946       else if (!noconvert)
2947         arg = default_conversion (arg);
2948       arg = non_lvalue (arg);
2949       break;
2950
2951     case NEGATE_EXPR:
2952       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2953             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2954             || typecode == VECTOR_TYPE))
2955         {
2956           error ("wrong type argument to unary minus");
2957           return error_mark_node;
2958         }
2959       else if (!noconvert)
2960         arg = default_conversion (arg);
2961       break;
2962
2963     case BIT_NOT_EXPR:
2964       /* ~ works on integer types and non float vectors. */
2965       if (typecode == INTEGER_TYPE
2966           || (typecode == VECTOR_TYPE
2967               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2968         {
2969           if (!noconvert)
2970             arg = default_conversion (arg);
2971         }
2972       else if (typecode == COMPLEX_TYPE)
2973         {
2974           code = CONJ_EXPR;
2975           pedwarn (input_location, OPT_pedantic,
2976                    "ISO C does not support %<~%> for complex conjugation");
2977           if (!noconvert)
2978             arg = default_conversion (arg);
2979         }
2980       else
2981         {
2982           error ("wrong type argument to bit-complement");
2983           return error_mark_node;
2984         }
2985       break;
2986
2987     case ABS_EXPR:
2988       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2989         {
2990           error ("wrong type argument to abs");
2991           return error_mark_node;
2992         }
2993       else if (!noconvert)
2994         arg = default_conversion (arg);
2995       break;
2996
2997     case CONJ_EXPR:
2998       /* Conjugating a real value is a no-op, but allow it anyway.  */
2999       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3000             || typecode == COMPLEX_TYPE))
3001         {
3002           error ("wrong type argument to conjugation");
3003           return error_mark_node;
3004         }
3005       else if (!noconvert)
3006         arg = default_conversion (arg);
3007       break;
3008
3009     case TRUTH_NOT_EXPR:
3010       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3011           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3012           && typecode != COMPLEX_TYPE)
3013         {
3014           error ("wrong type argument to unary exclamation mark");
3015           return error_mark_node;
3016         }
3017       arg = c_objc_common_truthvalue_conversion (input_location, arg);
3018       return invert_truthvalue (arg);
3019
3020     case REALPART_EXPR:
3021       if (TREE_CODE (arg) == COMPLEX_CST)
3022         return TREE_REALPART (arg);
3023       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3024         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3025       else
3026         return arg;
3027
3028     case IMAGPART_EXPR:
3029       if (TREE_CODE (arg) == COMPLEX_CST)
3030         return TREE_IMAGPART (arg);
3031       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3032         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3033       else
3034         return convert (TREE_TYPE (arg), integer_zero_node);
3035
3036     case PREINCREMENT_EXPR:
3037     case POSTINCREMENT_EXPR:
3038     case PREDECREMENT_EXPR:
3039     case POSTDECREMENT_EXPR:
3040
3041       /* Increment or decrement the real part of the value,
3042          and don't change the imaginary part.  */
3043       if (typecode == COMPLEX_TYPE)
3044         {
3045           tree real, imag;
3046
3047           pedwarn (input_location, OPT_pedantic,
3048                    "ISO C does not support %<++%> and %<--%> on complex types");
3049
3050           arg = stabilize_reference (arg);
3051           real = build_unary_op (REALPART_EXPR, arg, 1);
3052           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3053           real = build_unary_op (code, real, 1);
3054           if (real == error_mark_node || imag == error_mark_node)
3055             return error_mark_node;
3056           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3057                          real, imag);
3058         }
3059
3060       /* Report invalid types.  */
3061
3062       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3063           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3064         {
3065           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3066             error ("wrong type argument to increment");
3067           else
3068             error ("wrong type argument to decrement");
3069
3070           return error_mark_node;
3071         }
3072
3073       {
3074         tree inc;
3075         tree result_type = TREE_TYPE (arg);
3076
3077         arg = get_unwidened (arg, 0);
3078         argtype = TREE_TYPE (arg);
3079
3080         /* Compute the increment.  */
3081
3082         if (typecode == POINTER_TYPE)
3083           {
3084             /* If pointer target is an undefined struct,
3085                we just cannot know how to do the arithmetic.  */
3086             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3087               {
3088                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3089                   error ("increment of pointer to unknown structure");
3090                 else
3091                   error ("decrement of pointer to unknown structure");
3092               }
3093             else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3094                      || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
3095               {
3096                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3097                   pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3098                            "wrong type argument to increment");
3099                 else
3100                   pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3101                            "wrong type argument to decrement");
3102               }
3103
3104             inc = c_size_in_bytes (TREE_TYPE (result_type));
3105             inc = fold_convert (sizetype, inc);
3106           }
3107         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3108           {
3109             /* For signed fract types, we invert ++ to -- or
3110                -- to ++, and change inc from 1 to -1, because
3111                it is not possible to represent 1 in signed fract constants.
3112                For unsigned fract types, the result always overflows and
3113                we get an undefined (original) or the maximum value.  */
3114             if (code == PREINCREMENT_EXPR)
3115               code = PREDECREMENT_EXPR;
3116             else if (code == PREDECREMENT_EXPR)
3117               code = PREINCREMENT_EXPR;
3118             else if (code == POSTINCREMENT_EXPR)
3119               code = POSTDECREMENT_EXPR;
3120             else /* code == POSTDECREMENT_EXPR  */
3121               code = POSTINCREMENT_EXPR;
3122
3123             inc = integer_minus_one_node;
3124             inc = convert (argtype, inc);
3125           }
3126         else
3127           {
3128             inc = integer_one_node;
3129             inc = convert (argtype, inc);
3130           }
3131
3132         /* Complain about anything else that is not a true lvalue.  */
3133         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3134                                     || code == POSTINCREMENT_EXPR)
3135                                    ? lv_increment
3136                                    : lv_decrement)))
3137           return error_mark_node;
3138
3139         /* Report a read-only lvalue.  */
3140         if (TREE_READONLY (arg))
3141           {
3142             readonly_error (arg,
3143                             ((code == PREINCREMENT_EXPR
3144                               || code == POSTINCREMENT_EXPR)
3145                              ? lv_increment : lv_decrement));
3146             return error_mark_node;
3147           }
3148
3149         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3150           val = boolean_increment (code, arg);
3151         else
3152           val = build2 (code, TREE_TYPE (arg), arg, inc);
3153         TREE_SIDE_EFFECTS (val) = 1;
3154         val = convert (result_type, val);
3155         if (TREE_CODE (val) != code)
3156           TREE_NO_WARNING (val) = 1;
3157         return val;
3158       }
3159
3160     case ADDR_EXPR:
3161       /* Note that this operation never does default_conversion.  */
3162
3163       /* Let &* cancel out to simplify resulting code.  */
3164       if (TREE_CODE (arg) == INDIRECT_REF)
3165         {
3166           /* Don't let this be an lvalue.  */
3167           if (lvalue_p (TREE_OPERAND (arg, 0)))
3168             return non_lvalue (TREE_OPERAND (arg, 0));
3169           return TREE_OPERAND (arg, 0);
3170         }
3171
3172       /* For &x[y], return x+y */
3173       if (TREE_CODE (arg) == ARRAY_REF)
3174         {
3175           tree op0 = TREE_OPERAND (arg, 0);
3176           if (!c_mark_addressable (op0))
3177             return error_mark_node;
3178           return build_binary_op (EXPR_LOCATION (xarg), PLUS_EXPR,
3179                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3180                                    ? array_to_pointer_conversion (op0)
3181                                    : op0),
3182                                   TREE_OPERAND (arg, 1), 1);
3183         }
3184
3185       /* Anything not already handled and not a true memory reference
3186          or a non-lvalue array is an error.  */
3187       else if (typecode != FUNCTION_TYPE && !flag
3188                && !lvalue_or_else (arg, lv_addressof))
3189         return error_mark_node;
3190
3191       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3192       argtype = TREE_TYPE (arg);
3193
3194       /* If the lvalue is const or volatile, merge that into the type
3195          to which the address will point.  Note that you can't get a
3196          restricted pointer by taking the address of something, so we
3197          only have to deal with `const' and `volatile' here.  */
3198       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3199           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3200           argtype = c_build_type_variant (argtype,
3201                                           TREE_READONLY (arg),
3202                                           TREE_THIS_VOLATILE (arg));
3203
3204       if (!c_mark_addressable (arg))
3205         return error_mark_node;
3206
3207       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3208                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3209
3210       argtype = build_pointer_type (argtype);
3211
3212       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3213          when we have proper support for integer constant expressions.  */
3214       val = get_base_address (arg);
3215       if (val && TREE_CODE (val) == INDIRECT_REF
3216           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3217         {
3218           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3219
3220           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3221           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3222         }
3223
3224       val = build1 (ADDR_EXPR, argtype, arg);
3225
3226       return val;
3227
3228     default:
3229       gcc_unreachable ();
3230     }
3231
3232   if (argtype == 0)
3233     argtype = TREE_TYPE (arg);
3234   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3235                                 : fold_build1 (code, argtype, arg);
3236 }
3237
3238 /* Return nonzero if REF is an lvalue valid for this language.
3239    Lvalues can be assigned, unless their type has TYPE_READONLY.
3240    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3241
3242 static int
3243 lvalue_p (const_tree ref)
3244 {
3245   const enum tree_code code = TREE_CODE (ref);
3246
3247   switch (code)
3248     {
3249     case REALPART_EXPR:
3250     case IMAGPART_EXPR:
3251     case COMPONENT_REF:
3252       return lvalue_p (TREE_OPERAND (ref, 0));
3253
3254     case COMPOUND_LITERAL_EXPR:
3255     case STRING_CST:
3256       return 1;
3257
3258     case INDIRECT_REF:
3259     case ARRAY_REF:
3260     case VAR_DECL:
3261     case PARM_DECL:
3262     case RESULT_DECL:
3263     case ERROR_MARK:
3264       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3265               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3266
3267     case BIND_EXPR:
3268       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3269
3270     default:
3271       return 0;
3272     }
3273 }
3274 \f
3275 /* Give an error for storing in something that is 'const'.  */
3276
3277 static void
3278 readonly_error (tree arg, enum lvalue_use use)
3279 {
3280   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3281               || use == lv_asm);
3282   /* Using this macro rather than (for example) arrays of messages
3283      ensures that all the format strings are checked at compile
3284      time.  */
3285 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3286                                    : (use == lv_increment ? (I)         \
3287                                    : (use == lv_decrement ? (D) : (AS))))
3288   if (TREE_CODE (arg) == COMPONENT_REF)
3289     {
3290       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3291         readonly_error (TREE_OPERAND (arg, 0), use);
3292       else
3293         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3294                              G_("increment of read-only member %qD"),
3295                              G_("decrement of read-only member %qD"),
3296                              G_("read-only member %qD used as %<asm%> output")),
3297                TREE_OPERAND (arg, 1));
3298     }
3299   else if (TREE_CODE (arg) == VAR_DECL)
3300     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3301                          G_("increment of read-only variable %qD"),
3302                          G_("decrement of read-only variable %qD"),
3303                          G_("read-only variable %qD used as %<asm%> output")),
3304            arg);
3305   else
3306     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3307                          G_("increment of read-only location %qE"),
3308                          G_("decrement of read-only location %qE"),
3309                          G_("read-only location %qE used as %<asm%> output")),
3310            arg);
3311 }
3312
3313
3314 /* Return nonzero if REF is an lvalue valid for this language;
3315    otherwise, print an error message and return zero.  USE says
3316    how the lvalue is being used and so selects the error message.  */
3317
3318 static int
3319 lvalue_or_else (const_tree ref, enum lvalue_use use)
3320 {
3321   int win = lvalue_p (ref);
3322
3323   if (!win)
3324     lvalue_error (use);
3325
3326   return win;
3327 }
3328 \f
3329 /* Mark EXP saying that we need to be able to take the
3330    address of it; it should not be allocated in a register.
3331    Returns true if successful.  */
3332
3333 bool
3334 c_mark_addressable (tree exp)
3335 {
3336   tree x = exp;
3337
3338   while (1)
3339     switch (TREE_CODE (x))
3340       {
3341       case COMPONENT_REF:
3342         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3343           {
3344             error
3345               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3346             return false;
3347           }
3348
3349         /* ... fall through ...  */
3350
3351       case ADDR_EXPR:
3352       case ARRAY_REF:
3353       case REALPART_EXPR:
3354       case IMAGPART_EXPR:
3355         x = TREE_OPERAND (x, 0);
3356         break;
3357
3358       case COMPOUND_LITERAL_EXPR:
3359       case CONSTRUCTOR:
3360         TREE_ADDRESSABLE (x) = 1;
3361         return true;
3362
3363       case VAR_DECL:
3364       case CONST_DECL:
3365       case PARM_DECL:
3366       case RESULT_DECL:
3367         if (C_DECL_REGISTER (x)
3368             && DECL_NONLOCAL (x))
3369           {
3370             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3371               {
3372                 error
3373                   ("global register variable %qD used in nested function", x);
3374                 return false;
3375               }
3376             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3377           }
3378         else if (C_DECL_REGISTER (x))
3379           {
3380             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3381               error ("address of global register variable %qD requested", x);
3382             else
3383               error ("address of register variable %qD requested", x);
3384             return false;
3385           }
3386
3387         /* drops in */
3388       case FUNCTION_DECL:
3389         TREE_ADDRESSABLE (x) = 1;
3390         /* drops out */
3391       default:
3392         return true;
3393     }
3394 }
3395 \f
3396 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3397
3398 tree
3399 build_conditional_expr (tree ifexp, tree op1, tree op2)
3400 {
3401   tree type1;
3402   tree type2;
3403   enum tree_code code1;
3404   enum tree_code code2;
3405   tree result_type = NULL;
3406   tree orig_op1 = op1, orig_op2 = op2;
3407
3408   /* Promote both alternatives.  */
3409
3410   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3411     op1 = default_conversion (op1);
3412   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3413     op2 = default_conversion (op2);
3414
3415   if (TREE_CODE (ifexp) == ERROR_MARK
3416       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3417       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3418     return error_mark_node;
3419
3420   type1 = TREE_TYPE (op1);
3421   code1 = TREE_CODE (type1);
3422   type2 = TREE_TYPE (op2);
3423   code2 = TREE_CODE (type2);
3424
3425   /* C90 does not permit non-lvalue arrays in conditional expressions.
3426      In C99 they will be pointers by now.  */
3427   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3428     {
3429       error ("non-lvalue array in conditional expression");
3430       return error_mark_node;
3431     }
3432
3433   /* Quickly detect the usual case where op1 and op2 have the same type
3434      after promotion.  */
3435   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3436     {
3437       if (type1 == type2)
3438         result_type = type1;
3439       else
3440         result_type = TYPE_MAIN_VARIANT (type1);
3441     }
3442   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3443             || code1 == COMPLEX_TYPE)
3444            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3445                || code2 == COMPLEX_TYPE))
3446     {
3447       result_type = c_common_type (type1, type2);
3448
3449       /* If -Wsign-compare, warn here if type1 and type2 have
3450          different signedness.  We'll promote the signed to unsigned
3451          and later code won't know it used to be different.
3452          Do this check on the original types, so that explicit casts
3453          will be considered, but default promotions won't.  */
3454       if (warn_sign_compare && !skip_evaluation)
3455         {
3456           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3457           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3458
3459           if (unsigned_op1 ^ unsigned_op2)
3460             {
3461               bool ovf;
3462
3463               /* Do not warn if the result type is signed, since the
3464                  signed type will only be chosen if it can represent
3465                  all the values of the unsigned type.  */
3466               if (!TYPE_UNSIGNED (result_type))
3467                 /* OK */;
3468               /* Do not warn if the signed quantity is an unsuffixed
3469                  integer literal (or some static constant expression
3470                  involving such literals) and it is non-negative.  */
3471               else if ((unsigned_op2
3472                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3473                        || (unsigned_op1
3474                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3475                 /* OK */;
3476               else
3477                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3478             }
3479         }
3480     }
3481   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3482     {
3483       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3484         pedwarn (input_location, OPT_pedantic,
3485                  "ISO C forbids conditional expr with only one void side");
3486       result_type = void_type_node;
3487     }
3488   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3489     {
3490       if (comp_target_types (type1, type2))
3491         result_type = common_pointer_type (type1, type2);
3492       else if (null_pointer_constant_p (orig_op1))
3493         result_type = qualify_type (type2, type1);
3494       else if (null_pointer_constant_p (orig_op2))
3495         result_type = qualify_type (type1, type2);
3496       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3497         {
3498           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3499             pedwarn (input_location, OPT_pedantic,
3500                      "ISO C forbids conditional expr between "
3501                      "%<void *%> and function pointer");
3502           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3503                                                           TREE_TYPE (type2)));
3504         }
3505       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3506         {
3507           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3508             pedwarn (input_location, OPT_pedantic,
3509                      "ISO C forbids conditional expr between "
3510                      "%<void *%> and function pointer");
3511           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3512                                                           TREE_TYPE (type1)));
3513         }
3514       else
3515         {
3516           pedwarn (input_location, 0,
3517                    "pointer type mismatch in conditional expression");
3518           result_type = build_pointer_type (void_type_node);
3519         }
3520     }
3521   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3522     {
3523       if (!null_pointer_constant_p (orig_op2))
3524         pedwarn (input_location, 0,
3525                  "pointer/integer type mismatch in conditional expression");
3526       else
3527         {
3528           op2 = null_pointer_node;
3529         }
3530       result_type = type1;
3531     }
3532   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3533     {
3534       if (!null_pointer_constant_p (orig_op1))
3535         pedwarn (input_location, 0,
3536                  "pointer/integer type mismatch in conditional expression");
3537       else
3538         {
3539           op1 = null_pointer_node;
3540         }
3541       result_type = type2;
3542     }
3543
3544   if (!result_type)
3545     {
3546       if (flag_cond_mismatch)
3547         result_type = void_type_node;
3548       else
3549         {
3550           error ("type mismatch in conditional expression");
3551           return error_mark_node;
3552         }
3553     }
3554
3555   /* Merge const and volatile flags of the incoming types.  */
3556   result_type
3557     = build_type_variant (result_type,
3558                           TREE_READONLY (op1) || TREE_READONLY (op2),
3559                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3560
3561   if (result_type != TREE_TYPE (op1))
3562     op1 = convert_and_check (result_type, op1);
3563   if (result_type != TREE_TYPE (op2))
3564     op2 = convert_and_check (result_type, op2);
3565
3566   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3567 }
3568 \f
3569 /* Return a compound expression that performs two expressions and
3570    returns the value of the second of them.  */
3571
3572 tree
3573 build_compound_expr (tree expr1, tree expr2)
3574 {
3575   if (!TREE_SIDE_EFFECTS (expr1))
3576     {
3577       /* The left-hand operand of a comma expression is like an expression
3578          statement: with -Wunused, we should warn if it doesn't have
3579          any side-effects, unless it was explicitly cast to (void).  */
3580       if (warn_unused_value)
3581         {
3582           if (VOID_TYPE_P (TREE_TYPE (expr1))
3583               && CONVERT_EXPR_P (expr1))
3584             ; /* (void) a, b */
3585           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3586                    && TREE_CODE (expr1) == COMPOUND_EXPR
3587                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3588             ; /* (void) a, (void) b, c */
3589           else
3590             warning (OPT_Wunused_value,
3591                      "left-hand operand of comma expression has no effect");
3592         }
3593     }
3594
3595   /* With -Wunused, we should also warn if the left-hand operand does have
3596      side-effects, but computes a value which is not used.  For example, in
3597      `foo() + bar(), baz()' the result of the `+' operator is not used,
3598      so we should issue a warning.  */
3599   else if (warn_unused_value)
3600     warn_if_unused_value (expr1, input_location);
3601
3602   if (expr2 == error_mark_node)
3603     return error_mark_node;
3604
3605   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3606 }
3607
3608 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3609
3610 tree
3611 build_c_cast (tree type, tree expr)
3612 {
3613   tree value = expr;
3614
3615   if (type == error_mark_node || expr == error_mark_node)
3616     return error_mark_node;
3617
3618   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3619      only in <protocol> qualifications.  But when constructing cast expressions,
3620      the protocols do matter and must be kept around.  */
3621   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3622     return build1 (NOP_EXPR, type, expr);
3623
3624   type = TYPE_MAIN_VARIANT (type);
3625
3626   if (TREE_CODE (type) == ARRAY_TYPE)
3627     {
3628       error ("cast specifies array type");
3629       return error_mark_node;
3630     }
3631
3632   if (TREE_CODE (type) == FUNCTION_TYPE)
3633     {
3634       error ("cast specifies function type");
3635       return error_mark_node;
3636     }
3637
3638   if (!VOID_TYPE_P (type))
3639     {
3640       value = require_complete_type (value);
3641       if (value == error_mark_node)
3642         return error_mark_node;
3643     }
3644
3645   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3646     {
3647       if (TREE_CODE (type) == RECORD_TYPE
3648           || TREE_CODE (type) == UNION_TYPE)
3649         pedwarn (input_location, OPT_pedantic,
3650                  "ISO C forbids casting nonscalar to the same type");
3651     }
3652   else if (TREE_CODE (type) == UNION_TYPE)
3653     {
3654       tree field;
3655
3656       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3657         if (TREE_TYPE (field) != error_mark_node
3658             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3659                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3660           break;
3661
3662       if (field)
3663         {
3664           tree t;
3665
3666           pedwarn (input_location, OPT_pedantic,
3667                    "ISO C forbids casts to union type");
3668           t = digest_init (type,
3669                            build_constructor_single (type, field, value),
3670                            true, 0);
3671           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3672           return t;
3673         }
3674       error ("cast to union type from type not present in union");
3675       return error_mark_node;
3676     }
3677   else
3678     {
3679       tree otype, ovalue;
3680
3681       if (type == void_type_node)
3682         return build1 (CONVERT_EXPR, type, value);
3683
3684       otype = TREE_TYPE (value);
3685
3686       /* Optionally warn about potentially worrisome casts.  */
3687
3688       if (warn_cast_qual
3689           && TREE_CODE (type) == POINTER_TYPE
3690           && TREE_CODE (otype) == POINTER_TYPE)
3691         {
3692           tree in_type = type;
3693           tree in_otype = otype;
3694           int added = 0;
3695           int discarded = 0;
3696
3697           /* Check that the qualifiers on IN_TYPE are a superset of
3698              the qualifiers of IN_OTYPE.  The outermost level of
3699              POINTER_TYPE nodes is uninteresting and we stop as soon
3700              as we hit a non-POINTER_TYPE node on either type.  */
3701           do
3702             {
3703               in_otype = TREE_TYPE (in_otype);
3704               in_type = TREE_TYPE (in_type);
3705
3706               /* GNU C allows cv-qualified function types.  'const'
3707                  means the function is very pure, 'volatile' means it
3708                  can't return.  We need to warn when such qualifiers
3709                  are added, not when they're taken away.  */
3710               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3711                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3712                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3713               else
3714                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3715             }
3716           while (TREE_CODE (in_type) == POINTER_TYPE
3717                  && TREE_CODE (in_otype) == POINTER_TYPE);
3718
3719           if (added)
3720             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3721
3722           if (discarded)
3723             /* There are qualifiers present in IN_OTYPE that are not
3724                present in IN_TYPE.  */
3725             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3726         }
3727
3728       /* Warn about possible alignment problems.  */
3729       if (STRICT_ALIGNMENT
3730           && TREE_CODE (type) == POINTER_TYPE
3731           && TREE_CODE (otype) == POINTER_TYPE
3732           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3733           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3734           /* Don't warn about opaque types, where the actual alignment
3735              restriction is unknown.  */
3736           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3737                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3738                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3739           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3740         warning (OPT_Wcast_align,
3741                  "cast increases required alignment of target type");
3742
3743       if (TREE_CODE (type) == INTEGER_TYPE
3744           && TREE_CODE (otype) == POINTER_TYPE
3745           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3746       /* Unlike conversion of integers to pointers, where the
3747          warning is disabled for converting constants because
3748          of cases such as SIG_*, warn about converting constant
3749          pointers to integers. In some cases it may cause unwanted
3750          sign extension, and a warning is appropriate.  */
3751         warning (OPT_Wpointer_to_int_cast,
3752                  "cast from pointer to integer of different size");
3753
3754       if (TREE_CODE (value) == CALL_EXPR
3755           && TREE_CODE (type) != TREE_CODE (otype))
3756         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3757                  "to non-matching type %qT", otype, type);
3758
3759       if (TREE_CODE (type) == POINTER_TYPE
3760           && TREE_CODE (otype) == INTEGER_TYPE
3761           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3762           /* Don't warn about converting any constant.  */
3763           && !TREE_CONSTANT (value))
3764         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3765                  "of different size");
3766
3767       if (warn_strict_aliasing <= 2)
3768         strict_aliasing_warning (otype, type, expr);
3769
3770       /* If pedantic, warn for conversions between function and object
3771          pointer types, except for converting a null pointer constant
3772          to function pointer type.  */
3773       if (pedantic
3774           && TREE_CODE (type) == POINTER_TYPE
3775           && TREE_CODE (otype) == POINTER_TYPE
3776           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3777           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3778         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3779                  "conversion of function pointer to object pointer type");
3780
3781       if (pedantic
3782           && TREE_CODE (type) == POINTER_TYPE
3783           && TREE_CODE (otype) == POINTER_TYPE
3784           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3785           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3786           && !null_pointer_constant_p (value))
3787         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3788                  "conversion of object pointer to function pointer type");
3789
3790       ovalue = value;
3791       value = convert (type, value);
3792
3793       /* Ignore any integer overflow caused by the cast.  */
3794       if (TREE_CODE (value) == INTEGER_CST)
3795         {
3796           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3797             {
3798               if (!TREE_OVERFLOW (value))
3799                 {
3800                   /* Avoid clobbering a shared constant.  */
3801                   value = copy_node (value);
3802                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3803                 }
3804             }
3805           else if (TREE_OVERFLOW (value))
3806             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3807             value = build_int_cst_wide (TREE_TYPE (value),
3808                                         TREE_INT_CST_LOW (value),
3809                                         TREE_INT_CST_HIGH (value));
3810         }
3811     }
3812
3813   /* Don't let a cast be an lvalue.  */
3814   if (value == expr)
3815     value = non_lvalue (value);
3816
3817   return value;
3818 }
3819
3820 /* Interpret a cast of expression EXPR to type TYPE.  */
3821 tree
3822 c_cast_expr (struct c_type_name *type_name, tree expr)
3823 {
3824   tree type;
3825   int saved_wsp = warn_strict_prototypes;
3826
3827   /* This avoids warnings about unprototyped casts on
3828      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3829   if (TREE_CODE (expr) == INTEGER_CST)
3830     warn_strict_prototypes = 0;
3831   type = groktypename (type_name);
3832   warn_strict_prototypes = saved_wsp;
3833
3834   return build_c_cast (type, expr);
3835 }
3836 \f
3837 /* Build an assignment expression of lvalue LHS from value RHS.
3838    MODIFYCODE is the code for a binary operator that we use
3839    to combine the old value of LHS with RHS to get the new value.
3840    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3841
3842 tree
3843 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3844 {
3845   tree result;
3846   tree newrhs;
3847   tree lhstype = TREE_TYPE (lhs);
3848   tree olhstype = lhstype;
3849
3850   /* Types that aren't fully specified cannot be used in assignments.  */
3851   lhs = require_complete_type (lhs);
3852
3853   /* Avoid duplicate error messages from operands that had errors.  */
3854   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3855     return error_mark_node;
3856
3857   if (!lvalue_or_else (lhs, lv_assign))
3858     return error_mark_node;
3859
3860   STRIP_TYPE_NOPS (rhs);
3861
3862   newrhs = rhs;
3863
3864   /* If a binary op has been requested, combine the old LHS value with the RHS
3865      producing the value we should actually store into the LHS.  */
3866
3867   if (modifycode != NOP_EXPR)
3868     {
3869       lhs = stabilize_reference (lhs);
3870       newrhs = build_binary_op (EXPR_LOCATION (lhs),
3871                                 modifycode, lhs, rhs, 1);
3872     }
3873
3874   /* Give an error for storing in something that is 'const'.  */
3875
3876   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3877       || ((TREE_CODE (lhstype) == RECORD_TYPE
3878            || TREE_CODE (lhstype) == UNION_TYPE)
3879           && C_TYPE_FIELDS_READONLY (lhstype)))
3880     {
3881       readonly_error (lhs, lv_assign);
3882       return error_mark_node;
3883     }
3884
3885   /* If storing into a structure or union member,
3886      it has probably been given type `int'.
3887      Compute the type that would go with
3888      the actual amount of storage the member occupies.  */
3889
3890   if (TREE_CODE (lhs) == COMPONENT_REF
3891       && (TREE_CODE (lhstype) == INTEGER_TYPE
3892           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3893           || TREE_CODE (lhstype) == REAL_TYPE
3894           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3895     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3896
3897   /* If storing in a field that is in actuality a short or narrower than one,
3898      we must store in the field in its actual type.  */
3899
3900   if (lhstype != TREE_TYPE (lhs))
3901     {
3902       lhs = copy_node (lhs);
3903       TREE_TYPE (lhs) = lhstype;
3904     }
3905
3906   /* Convert new value to destination type.  */
3907
3908   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3909                                    NULL_TREE, NULL_TREE, 0);
3910   if (TREE_CODE (newrhs) == ERROR_MARK)
3911     return error_mark_node;
3912
3913   /* Emit ObjC write barrier, if necessary.  */
3914   if (c_dialect_objc () && flag_objc_gc)
3915     {
3916       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3917       if (result)
3918         return result;
3919     }
3920
3921   /* Scan operands.  */
3922
3923   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3924   TREE_SIDE_EFFECTS (result) = 1;
3925
3926   /* If we got the LHS in a different type for storing in,
3927      convert the result back to the nominal type of LHS
3928      so that the value we return always has the same type
3929      as the LHS argument.  */
3930
3931   if (olhstype == TREE_TYPE (result))
3932     return result;
3933   return convert_for_assignment (olhstype, result, ic_assign,
3934                                  NULL_TREE, NULL_TREE, 0);
3935 }
3936 \f
3937 /* Convert value RHS to type TYPE as preparation for an assignment
3938    to an lvalue of type TYPE.
3939    The real work of conversion is done by `convert'.
3940    The purpose of this function is to generate error messages
3941    for assignments that are not allowed in C.
3942    ERRTYPE says whether it is argument passing, assignment,
3943    initialization or return.
3944
3945    FUNCTION is a tree for the function being called.
3946    PARMNUM is the number of the argument, for printing in error messages.  */
3947
3948 static tree
3949 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3950                         tree fundecl, tree function, int parmnum)
3951 {
3952   enum tree_code codel = TREE_CODE (type);
3953   tree rhstype;
3954   enum tree_code coder;
3955   tree rname = NULL_TREE;
3956   bool objc_ok = false;
3957
3958   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3959     {
3960       tree selector;
3961       /* Change pointer to function to the function itself for
3962          diagnostics.  */
3963       if (TREE_CODE (function) == ADDR_EXPR
3964           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3965         function = TREE_OPERAND (function, 0);
3966
3967       /* Handle an ObjC selector specially for diagnostics.  */
3968       selector = objc_message_selector ();
3969       rname = function;
3970       if (selector && parmnum > 2)
3971         {
3972           rname = selector;
3973           parmnum -= 2;
3974         }
3975     }
3976
3977   /* This macro is used to emit diagnostics to ensure that all format
3978      strings are complete sentences, visible to gettext and checked at
3979      compile time.  */
3980 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
3981   do {                                                                   \
3982     switch (errtype)                                                     \
3983       {                                                                  \
3984       case ic_argpass:                                                   \
3985         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
3986           inform (fundecl ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,   \
3987                   "expected %qT but argument is of type %qT",            \
3988                   type, rhstype);                                        \
3989         break;                                                           \
3990       case ic_argpass_nonproto:                                          \
3991         warning (OPT, AR, parmnum, rname);                               \
3992         break;                                                           \
3993       case ic_assign:                                                    \
3994         pedwarn (LOCATION, OPT, AS);                                     \
3995         break;                                                           \
3996       case ic_init:                                                      \
3997         pedwarn (LOCATION, OPT, IN);                                     \
3998         break;                                                           \
3999       case ic_return:                                                    \
4000         pedwarn (LOCATION, OPT, RE);                                     \
4001         break;                                                           \
4002       default:                                                           \
4003         gcc_unreachable ();                                              \
4004       }                                                                  \
4005   } while (0)
4006
4007   STRIP_TYPE_NOPS (rhs);
4008
4009   if (optimize && TREE_CODE (rhs) == VAR_DECL
4010            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
4011     rhs = decl_constant_value_for_broken_optimization (rhs);
4012
4013   rhstype = TREE_TYPE (rhs);
4014   coder = TREE_CODE (rhstype);
4015
4016   if (coder == ERROR_MARK)
4017     return error_mark_node;
4018
4019   if (c_dialect_objc ())
4020     {
4021       int parmno;
4022
4023       switch (errtype)
4024         {
4025         case ic_return:
4026           parmno = 0;
4027           break;
4028
4029         case ic_assign:
4030           parmno = -1;
4031           break;
4032
4033         case ic_init:
4034           parmno = -2;
4035           break;
4036
4037         default:
4038           parmno = parmnum;
4039           break;
4040         }
4041
4042       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4043     }
4044
4045   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4046     return rhs;
4047
4048   if (coder == VOID_TYPE)
4049     {
4050       /* Except for passing an argument to an unprototyped function,
4051          this is a constraint violation.  When passing an argument to
4052          an unprototyped function, it is compile-time undefined;
4053          making it a constraint in that case was rejected in
4054          DR#252.  */
4055       error ("void value not ignored as it ought to be");
4056       return error_mark_node;
4057     }
4058   rhs = require_complete_type (rhs);
4059   if (rhs == error_mark_node)
4060     return error_mark_node;
4061   /* A type converts to a reference to it.
4062      This code doesn't fully support references, it's just for the
4063      special case of va_start and va_copy.  */
4064   if (codel == REFERENCE_TYPE
4065       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4066     {
4067       if (!lvalue_p (rhs))
4068         {
4069           error ("cannot pass rvalue to reference parameter");
4070           return error_mark_node;
4071         }
4072       if (!c_mark_addressable (rhs))
4073         return error_mark_node;
4074       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4075
4076       /* We already know that these two types are compatible, but they
4077          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4078          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4079          likely to be va_list, a typedef to __builtin_va_list, which
4080          is different enough that it will cause problems later.  */
4081       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4082         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4083
4084       rhs = build1 (NOP_EXPR, type, rhs);
4085       return rhs;
4086     }
4087   /* Some types can interconvert without explicit casts.  */
4088   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4089            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4090     return convert (type, rhs);
4091   /* Arithmetic types all interconvert, and enum is treated like int.  */
4092   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4093             || codel == FIXED_POINT_TYPE
4094             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4095             || codel == BOOLEAN_TYPE)
4096            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4097                || coder == FIXED_POINT_TYPE
4098                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4099                || coder == BOOLEAN_TYPE))
4100     return convert_and_check (type, rhs);
4101
4102   /* Aggregates in different TUs might need conversion.  */
4103   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4104       && codel == coder
4105       && comptypes (type, rhstype))
4106     return convert_and_check (type, rhs);
4107
4108   /* Conversion to a transparent union from its member types.
4109      This applies only to function arguments.  */
4110   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4111       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4112     {
4113       tree memb, marginal_memb = NULL_TREE;
4114
4115       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4116         {
4117           tree memb_type = TREE_TYPE (memb);
4118
4119           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4120                          TYPE_MAIN_VARIANT (rhstype)))
4121             break;
4122
4123           if (TREE_CODE (memb_type) != POINTER_TYPE)
4124             continue;
4125
4126           if (coder == POINTER_TYPE)
4127             {
4128               tree ttl = TREE_TYPE (memb_type);
4129               tree ttr = TREE_TYPE (rhstype);
4130
4131               /* Any non-function converts to a [const][volatile] void *
4132                  and vice versa; otherwise, targets must be the same.
4133                  Meanwhile, the lhs target must have all the qualifiers of
4134                  the rhs.  */
4135               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4136                   || comp_target_types (memb_type, rhstype))
4137                 {
4138                   /* If this type won't generate any warnings, use it.  */
4139                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4140                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4141                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4142                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4143                              == TYPE_QUALS (ttr))
4144                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4145                              == TYPE_QUALS (ttl))))
4146                     break;
4147
4148                   /* Keep looking for a better type, but remember this one.  */
4149                   if (!marginal_memb)
4150                     marginal_memb = memb;
4151                 }
4152             }
4153
4154           /* Can convert integer zero to any pointer type.  */
4155           if (null_pointer_constant_p (rhs))
4156             {
4157               rhs = null_pointer_node;
4158               break;
4159             }
4160         }
4161
4162       if (memb || marginal_memb)
4163         {
4164           if (!memb)
4165             {
4166               /* We have only a marginally acceptable member type;
4167                  it needs a warning.  */
4168               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4169               tree ttr = TREE_TYPE (rhstype);
4170
4171               /* Const and volatile mean something different for function
4172                  types, so the usual warnings are not appropriate.  */
4173               if (TREE_CODE (ttr) == FUNCTION_TYPE
4174                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4175                 {
4176                   /* Because const and volatile on functions are
4177                      restrictions that say the function will not do
4178                      certain things, it is okay to use a const or volatile
4179                      function where an ordinary one is wanted, but not
4180                      vice-versa.  */
4181                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4182                     WARN_FOR_ASSIGNMENT (input_location, 0,
4183                                          G_("passing argument %d of %qE "
4184                                             "makes qualified function "
4185                                             "pointer from unqualified"),
4186                                          G_("assignment makes qualified "
4187                                             "function pointer from "
4188                                             "unqualified"),
4189                                          G_("initialization makes qualified "
4190                                             "function pointer from "
4191                                             "unqualified"),
4192                                          G_("return makes qualified function "
4193                                             "pointer from unqualified"));
4194                 }
4195               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4196                 WARN_FOR_ASSIGNMENT (input_location, 0,
4197                                      G_("passing argument %d of %qE discards "
4198                                         "qualifiers from pointer target type"),
4199                                      G_("assignment discards qualifiers "
4200                                         "from pointer target type"),
4201                                      G_("initialization discards qualifiers "
4202                                         "from pointer target type"),
4203                                      G_("return discards qualifiers from "
4204                                         "pointer target type"));
4205
4206               memb = marginal_memb;
4207             }
4208
4209           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4210             pedwarn (input_location, OPT_pedantic,
4211                      "ISO C prohibits argument conversion to union type");
4212
4213           rhs = fold_convert (TREE_TYPE (memb), rhs);
4214           return build_constructor_single (type, memb, rhs);
4215         }
4216     }
4217
4218   /* Conversions among pointers */
4219   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4220            && (coder == codel))
4221     {
4222       tree ttl = TREE_TYPE (type);
4223       tree ttr = TREE_TYPE (rhstype);
4224       tree mvl = ttl;
4225       tree mvr = ttr;
4226       bool is_opaque_pointer;
4227       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4228
4229       if (TREE_CODE (mvl) != ARRAY_TYPE)
4230         mvl = TYPE_MAIN_VARIANT (mvl);
4231       if (TREE_CODE (mvr) != ARRAY_TYPE)
4232         mvr = TYPE_MAIN_VARIANT (mvr);
4233       /* Opaque pointers are treated like void pointers.  */
4234       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4235
4236       /* C++ does not allow the implicit conversion void* -> T*.  However,
4237          for the purpose of reducing the number of false positives, we
4238          tolerate the special case of
4239
4240                 int *p = NULL;
4241
4242          where NULL is typically defined in C to be '(void *) 0'.  */
4243       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4244         warning (OPT_Wc___compat, "request for implicit conversion from "
4245                  "%qT to %qT not permitted in C++", rhstype, type);
4246
4247       /* Check if the right-hand side has a format attribute but the
4248          left-hand side doesn't.  */
4249       if (warn_missing_format_attribute
4250           && check_missing_format_attribute (type, rhstype))
4251         {
4252           switch (errtype)
4253           {
4254           case ic_argpass:
4255           case ic_argpass_nonproto:
4256             warning (OPT_Wmissing_format_attribute,
4257                      "argument %d of %qE might be "
4258                      "a candidate for a format attribute",
4259                      parmnum, rname);
4260             break;
4261           case ic_assign:
4262             warning (OPT_Wmissing_format_attribute,
4263                      "assignment left-hand side might be "
4264                      "a candidate for a format attribute");
4265             break;
4266           case ic_init:
4267             warning (OPT_Wmissing_format_attribute,
4268                      "initialization left-hand side might be "
4269                      "a candidate for a format attribute");
4270             break;
4271           case ic_return:
4272             warning (OPT_Wmissing_format_attribute,
4273                      "return type might be "
4274                      "a candidate for a format attribute");
4275             break;
4276           default:
4277             gcc_unreachable ();
4278           }
4279         }
4280
4281       /* Any non-function converts to a [const][volatile] void *
4282          and vice versa; otherwise, targets must be the same.
4283          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4284       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4285           || (target_cmp = comp_target_types (type, rhstype))
4286           || is_opaque_pointer
4287           || (c_common_unsigned_type (mvl)
4288               == c_common_unsigned_type (mvr)))
4289         {
4290           if (pedantic
4291               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4292                   ||
4293                   (VOID_TYPE_P (ttr)
4294                    && !null_pointer_constant_p (rhs)
4295                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4296             WARN_FOR_ASSIGNMENT (input_location, OPT_pedantic,
4297                                  G_("ISO C forbids passing argument %d of "
4298                                     "%qE between function pointer "
4299                                     "and %<void *%>"),
4300                                  G_("ISO C forbids assignment between "
4301                                     "function pointer and %<void *%>"),
4302                                  G_("ISO C forbids initialization between "
4303                                     "function pointer and %<void *%>"),
4304                                  G_("ISO C forbids return between function "
4305                                     "pointer and %<void *%>"));
4306           /* Const and volatile mean something different for function types,
4307              so the usual warnings are not appropriate.  */
4308           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4309                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4310             {
4311               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4312                 {
4313                   /* Types differing only by the presence of the 'volatile'
4314                      qualifier are acceptable if the 'volatile' has been added
4315                      in by the Objective-C EH machinery.  */
4316                   if (!objc_type_quals_match (ttl, ttr))
4317                     WARN_FOR_ASSIGNMENT (input_location, 0,
4318                                          G_("passing argument %d of %qE discards "
4319                                             "qualifiers from pointer target type"),
4320                                          G_("assignment discards qualifiers "
4321                                             "from pointer target type"),
4322                                          G_("initialization discards qualifiers "
4323                                             "from pointer target type"),
4324                                          G_("return discards qualifiers from "
4325                                             "pointer target type"));
4326                 }
4327               /* If this is not a case of ignoring a mismatch in signedness,
4328                  no warning.  */
4329               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4330                        || target_cmp)
4331                 ;
4332               /* If there is a mismatch, do warn.  */
4333               else if (warn_pointer_sign)
4334                 WARN_FOR_ASSIGNMENT (input_location, OPT_Wpointer_sign,
4335                                      G_("pointer targets in passing argument "
4336                                         "%d of %qE differ in signedness"),
4337                                      G_("pointer targets in assignment "
4338                                         "differ in signedness"),
4339                                      G_("pointer targets in initialization "
4340                                         "differ in signedness"),
4341                                      G_("pointer targets in return differ "
4342                                         "in signedness"));
4343             }
4344           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4345                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4346             {
4347               /* Because const and volatile on functions are restrictions
4348                  that say the function will not do certain things,
4349                  it is okay to use a const or volatile function
4350                  where an ordinary one is wanted, but not vice-versa.  */
4351               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4352                 WARN_FOR_ASSIGNMENT (input_location, 0,
4353                                      G_("passing argument %d of %qE makes "
4354                                         "qualified function pointer "
4355                                         "from unqualified"),
4356                                      G_("assignment makes qualified function "
4357                                         "pointer from unqualified"),
4358                                      G_("initialization makes qualified "
4359                                         "function pointer from unqualified"),
4360                                      G_("return makes qualified function "
4361                                         "pointer from unqualified"));
4362             }
4363         }
4364       else
4365         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4366         if (!objc_ok)
4367           WARN_FOR_ASSIGNMENT (input_location, 0,
4368                                G_("passing argument %d of %qE from "
4369                                   "incompatible pointer type"),
4370                                G_("assignment from incompatible pointer type"),
4371                                G_("initialization from incompatible "
4372                                   "pointer type"),
4373                                G_("return from incompatible pointer type"));
4374
4375       return convert (type, rhs);
4376     }
4377   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4378     {
4379       /* ??? This should not be an error when inlining calls to
4380          unprototyped functions.  */
4381       error ("invalid use of non-lvalue array");
4382       return error_mark_node;
4383     }
4384   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4385     {
4386       /* An explicit constant 0 can convert to a pointer,
4387          or one that results from arithmetic, even including
4388          a cast to integer type.  */
4389       if (!null_pointer_constant_p (rhs))
4390         WARN_FOR_ASSIGNMENT (input_location, 0,
4391                              G_("passing argument %d of %qE makes "
4392                                 "pointer from integer without a cast"),
4393                              G_("assignment makes pointer from integer "
4394                                 "without a cast"),
4395                              G_("initialization makes pointer from "
4396                                 "integer without a cast"),
4397                              G_("return makes pointer from integer "
4398                                 "without a cast"));
4399
4400       return convert (type, rhs);
4401     }
4402   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4403     {
4404       WARN_FOR_ASSIGNMENT (input_location, 0,
4405                            G_("passing argument %d of %qE makes integer "
4406                               "from pointer without a cast"),
4407                            G_("assignment makes integer from pointer "
4408                               "without a cast"),
4409                            G_("initialization makes integer from pointer "
4410                               "without a cast"),
4411                            G_("return makes integer from pointer "
4412                               "without a cast"));
4413       return convert (type, rhs);
4414     }
4415   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4416     return convert (type, rhs);
4417
4418   switch (errtype)
4419     {
4420     case ic_argpass:
4421     case ic_argpass_nonproto:
4422       /* ??? This should not be an error when inlining calls to
4423          unprototyped functions.  */
4424       error ("incompatible type for argument %d of %qE", parmnum, rname);
4425       break;
4426     case ic_assign:
4427       error ("incompatible types in assignment");
4428       break;
4429     case ic_init:
4430       error ("incompatible types in initialization");
4431       break;
4432     case ic_return:
4433       error ("incompatible types in return");
4434       break;
4435     default:
4436       gcc_unreachable ();
4437     }
4438
4439   return error_mark_node;
4440 }
4441 \f
4442 /* If VALUE is a compound expr all of whose expressions are constant, then
4443    return its value.  Otherwise, return error_mark_node.
4444
4445    This is for handling COMPOUND_EXPRs as initializer elements
4446    which is allowed with a warning when -pedantic is specified.  */
4447
4448 static tree
4449 valid_compound_expr_initializer (tree value, tree endtype)
4450 {
4451   if (TREE_CODE (value) == COMPOUND_EXPR)
4452     {
4453       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4454           == error_mark_node)
4455         return error_mark_node;
4456       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4457                                               endtype);
4458     }
4459   else if (!initializer_constant_valid_p (value, endtype))
4460     return error_mark_node;
4461   else
4462     return value;
4463 }
4464 \f
4465 /* Perform appropriate conversions on the initial value of a variable,
4466    store it in the declaration DECL,
4467    and print any error messages that are appropriate.
4468    If the init is invalid, store an ERROR_MARK.  */
4469
4470 void
4471 store_init_value (tree decl, tree init)
4472 {
4473   tree value, type;
4474
4475   /* If variable's type was invalidly declared, just ignore it.  */
4476
4477   type = TREE_TYPE (decl);
4478   if (TREE_CODE (type) == ERROR_MARK)
4479     return;
4480
4481   /* Digest the specified initializer into an expression.  */
4482
4483   value = digest_init (type, init, true, TREE_STATIC (decl));
4484
4485   /* Store the expression if valid; else report error.  */
4486
4487   if (!in_system_header
4488       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4489     warning (OPT_Wtraditional, "traditional C rejects automatic "
4490              "aggregate initialization");
4491
4492   DECL_INITIAL (decl) = value;
4493
4494   /* ANSI wants warnings about out-of-range constant initializers.  */
4495   STRIP_TYPE_NOPS (value);
4496   if (TREE_STATIC (decl))
4497     constant_expression_warning (value);
4498
4499   /* Check if we need to set array size from compound literal size.  */
4500   if (TREE_CODE (type) == ARRAY_TYPE
4501       && TYPE_DOMAIN (type) == 0
4502       && value != error_mark_node)
4503     {
4504       tree inside_init = init;
4505
4506       STRIP_TYPE_NOPS (inside_init);
4507       inside_init = fold (inside_init);
4508
4509       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4510         {
4511           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4512
4513           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4514             {
4515               /* For int foo[] = (int [3]){1}; we need to set array size
4516                  now since later on array initializer will be just the
4517                  brace enclosed list of the compound literal.  */
4518               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4519               TREE_TYPE (decl) = type;
4520               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4521               layout_type (type);
4522               layout_decl (cldecl, 0);
4523             }
4524         }
4525     }
4526 }
4527 \f
4528 /* Methods for storing and printing names for error messages.  */
4529
4530 /* Implement a spelling stack that allows components of a name to be pushed
4531    and popped.  Each element on the stack is this structure.  */
4532
4533 struct spelling
4534 {
4535   int kind;
4536   union
4537     {
4538       unsigned HOST_WIDE_INT i;
4539       const char *s;
4540     } u;
4541 };
4542
4543 #define SPELLING_STRING 1
4544 #define SPELLING_MEMBER 2
4545 #define SPELLING_BOUNDS 3
4546
4547 static struct spelling *spelling;       /* Next stack element (unused).  */
4548 static struct spelling *spelling_base;  /* Spelling stack base.  */
4549 static int spelling_size;               /* Size of the spelling stack.  */
4550
4551 /* Macros to save and restore the spelling stack around push_... functions.
4552    Alternative to SAVE_SPELLING_STACK.  */
4553
4554 #define SPELLING_DEPTH() (spelling - spelling_base)
4555 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4556
4557 /* Push an element on the spelling stack with type KIND and assign VALUE
4558    to MEMBER.  */
4559
4560 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4561 {                                                                       \
4562   int depth = SPELLING_DEPTH ();                                        \
4563                                                                         \
4564   if (depth >= spelling_size)                                           \
4565     {                                                                   \
4566       spelling_size += 10;                                              \
4567       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4568                                   spelling_size);                       \
4569       RESTORE_SPELLING_DEPTH (depth);                                   \
4570     }                                                                   \
4571                                                                         \
4572   spelling->kind = (KIND);                                              \
4573   spelling->MEMBER = (VALUE);                                           \
4574   spelling++;                                                           \
4575 }
4576
4577 /* Push STRING on the stack.  Printed literally.  */
4578
4579 static void
4580 push_string (const char *string)
4581 {
4582   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4583 }
4584
4585 /* Push a member name on the stack.  Printed as '.' STRING.  */
4586
4587 static void
4588 push_member_name (tree decl)
4589 {
4590   const char *const string
4591     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4592   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4593 }
4594
4595 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4596
4597 static void
4598 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4599 {
4600   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4601 }
4602
4603 /* Compute the maximum size in bytes of the printed spelling.  */
4604
4605 static int
4606 spelling_length (void)
4607 {
4608   int size = 0;
4609   struct spelling *p;
4610
4611   for (p = spelling_base; p < spelling; p++)
4612     {
4613       if (p->kind == SPELLING_BOUNDS)
4614         size += 25;
4615       else
4616         size += strlen (p->u.s) + 1;
4617     }
4618
4619   return size;
4620 }
4621
4622 /* Print the spelling to BUFFER and return it.  */
4623
4624 static char *
4625 print_spelling (char *buffer)
4626 {
4627   char *d = buffer;
4628   struct spelling *p;
4629
4630   for (p = spelling_base; p < spelling; p++)
4631     if (p->kind == SPELLING_BOUNDS)
4632       {
4633         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4634         d += strlen (d);
4635       }
4636     else
4637       {
4638         const char *s;
4639         if (p->kind == SPELLING_MEMBER)
4640           *d++ = '.';
4641         for (s = p->u.s; (*d = *s++); d++)
4642           ;
4643       }
4644   *d++ = '\0';
4645   return buffer;
4646 }
4647
4648 /* Issue an error message for a bad initializer component.
4649    MSGID identifies the message.
4650    The component name is taken from the spelling stack.  */
4651
4652 void
4653 error_init (const char *msgid)
4654 {
4655   char *ofwhat;
4656
4657   error ("%s", _(msgid));
4658   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4659   if (*ofwhat)
4660     error ("(near initialization for %qs)", ofwhat);
4661 }
4662
4663 /* Issue a pedantic warning for a bad initializer component.  OPT is
4664    the option OPT_* (from options.h) controlling this warning or 0 if
4665    it is unconditionally given.  MSGID identifies the message.  The
4666    component name is taken from the spelling stack.  */
4667
4668 void
4669 pedwarn_init (location_t location, int opt, const char *msgid)
4670 {
4671   char *ofwhat;
4672
4673   pedwarn (location, opt, "%s", _(msgid));
4674   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4675   if (*ofwhat)
4676     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
4677 }
4678
4679 /* Issue a warning for a bad initializer component.
4680
4681    OPT is the OPT_W* value corresponding to the warning option that
4682    controls this warning.  MSGID identifies the message.  The
4683    component name is taken from the spelling stack.  */
4684
4685 static void
4686 warning_init (int opt, const char *msgid)
4687 {
4688   char *ofwhat;
4689
4690   warning (opt, "%s", _(msgid));
4691   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4692   if (*ofwhat)
4693     warning (opt, "(near initialization for %qs)", ofwhat);
4694 }
4695 \f
4696 /* If TYPE is an array type and EXPR is a parenthesized string
4697    constant, warn if pedantic that EXPR is being used to initialize an
4698    object of type TYPE.  */
4699
4700 void
4701 maybe_warn_string_init (tree type, struct c_expr expr)
4702 {
4703   if (pedantic
4704       && TREE_CODE (type) == ARRAY_TYPE
4705       && TREE_CODE (expr.value) == STRING_CST
4706       && expr.original_code != STRING_CST)
4707     pedwarn_init (input_location, OPT_pedantic,
4708                   "array initialized from parenthesized string constant");
4709 }
4710
4711 /* Digest the parser output INIT as an initializer for type TYPE.
4712    Return a C expression of type TYPE to represent the initial value.
4713
4714    If INIT is a string constant, STRICT_STRING is true if it is
4715    unparenthesized or we should not warn here for it being parenthesized.
4716    For other types of INIT, STRICT_STRING is not used.
4717
4718    REQUIRE_CONSTANT requests an error if non-constant initializers or
4719    elements are seen.  */
4720
4721 static tree
4722 digest_init (tree type, tree init, bool strict_string, int require_constant)
4723 {
4724   enum tree_code code = TREE_CODE (type);
4725   tree inside_init = init;
4726
4727   if (type == error_mark_node
4728       || !init
4729       || init == error_mark_node
4730       || TREE_TYPE (init) == error_mark_node)
4731     return error_mark_node;
4732
4733   STRIP_TYPE_NOPS (inside_init);
4734
4735   inside_init = fold (inside_init);
4736
4737   /* Initialization of an array of chars from a string constant
4738      optionally enclosed in braces.  */
4739
4740   if (code == ARRAY_TYPE && inside_init
4741       && TREE_CODE (inside_init) == STRING_CST)
4742     {
4743       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4744       /* Note that an array could be both an array of character type
4745          and an array of wchar_t if wchar_t is signed char or unsigned
4746          char.  */
4747       bool char_array = (typ1 == char_type_node
4748                          || typ1 == signed_char_type_node
4749                          || typ1 == unsigned_char_type_node);
4750       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4751       bool char16_array = !!comptypes (typ1, char16_type_node);
4752       bool char32_array = !!comptypes (typ1, char32_type_node);
4753
4754       if (char_array || wchar_array || char16_array || char32_array)
4755         {
4756           struct c_expr expr;
4757           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
4758           expr.value = inside_init;
4759           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4760           maybe_warn_string_init (type, expr);
4761
4762           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4763                          TYPE_MAIN_VARIANT (type)))
4764             return inside_init;
4765
4766           if (char_array)
4767             {
4768               if (typ2 != char_type_node)
4769                 {
4770                   error_init ("char-array initialized from wide string");
4771                   return error_mark_node;
4772                 }
4773             }
4774           else
4775             {
4776               if (typ2 == char_type_node)
4777                 {
4778                   error_init ("wide character array initialized from non-wide "
4779                               "string");
4780                   return error_mark_node;
4781                 }
4782               else if (!comptypes(typ1, typ2))
4783                 {
4784                   error_init ("wide character array initialized from "
4785                               "incompatible wide string");
4786                   return error_mark_node;
4787                 }
4788             }
4789
4790           TREE_TYPE (inside_init) = type;
4791           if (TYPE_DOMAIN (type) != 0
4792               && TYPE_SIZE (type) != 0
4793               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4794               /* Subtract the size of a single (possibly wide) character
4795                  because it's ok to ignore the terminating null char
4796                  that is counted in the length of the constant.  */
4797               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4798                                        TREE_STRING_LENGTH (inside_init)
4799                                        - (TYPE_PRECISION (typ1)
4800                                           / BITS_PER_UNIT)))
4801             pedwarn_init (input_location, 0,
4802                           "initializer-string for array of chars is too long");
4803
4804           return inside_init;
4805         }
4806       else if (INTEGRAL_TYPE_P (typ1))
4807         {
4808           error_init ("array of inappropriate type initialized "
4809                       "from string constant");
4810           return error_mark_node;
4811         }
4812     }
4813
4814   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4815      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4816      below and handle as a constructor.  */
4817   if (code == VECTOR_TYPE
4818       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4819       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4820       && TREE_CONSTANT (inside_init))
4821     {
4822       if (TREE_CODE (inside_init) == VECTOR_CST
4823           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4824                         TYPE_MAIN_VARIANT (type)))
4825         return inside_init;
4826
4827       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4828         {
4829           unsigned HOST_WIDE_INT ix;
4830           tree value;
4831           bool constant_p = true;
4832
4833           /* Iterate through elements and check if all constructor
4834              elements are *_CSTs.  */
4835           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4836             if (!CONSTANT_CLASS_P (value))
4837               {
4838                 constant_p = false;
4839                 break;
4840               }
4841
4842           if (constant_p)
4843             return build_vector_from_ctor (type,
4844                                            CONSTRUCTOR_ELTS (inside_init));
4845         }
4846     }
4847
4848   if (warn_sequence_point)
4849     verify_sequence_points (inside_init);
4850
4851   /* Any type can be initialized
4852      from an expression of the same type, optionally with braces.  */
4853
4854   if (inside_init && TREE_TYPE (inside_init) != 0
4855       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4856                      TYPE_MAIN_VARIANT (type))
4857           || (code == ARRAY_TYPE
4858               && comptypes (TREE_TYPE (inside_init), type))
4859           || (code == VECTOR_TYPE
4860               && comptypes (TREE_TYPE (inside_init), type))
4861           || (code == POINTER_TYPE
4862               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4863               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4864                             TREE_TYPE (type)))))
4865     {
4866       if (code == POINTER_TYPE)
4867         {
4868           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4869             {
4870               if (TREE_CODE (inside_init) == STRING_CST
4871                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4872                 inside_init = array_to_pointer_conversion (inside_init);
4873               else
4874                 {
4875                   error_init ("invalid use of non-lvalue array");
4876                   return error_mark_node;
4877                 }
4878             }
4879         }
4880
4881       if (code == VECTOR_TYPE)
4882         /* Although the types are compatible, we may require a
4883            conversion.  */
4884         inside_init = convert (type, inside_init);
4885
4886       if (require_constant
4887           && (code == VECTOR_TYPE || !flag_isoc99)
4888           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4889         {
4890           /* As an extension, allow initializing objects with static storage
4891              duration with compound literals (which are then treated just as
4892              the brace enclosed list they contain).  Also allow this for
4893              vectors, as we can only assign them with compound literals.  */
4894           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4895           inside_init = DECL_INITIAL (decl);
4896         }
4897
4898       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4899           && TREE_CODE (inside_init) != CONSTRUCTOR)
4900         {
4901           error_init ("array initialized from non-constant array expression");
4902           return error_mark_node;
4903         }
4904
4905       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4906         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4907
4908       /* Compound expressions can only occur here if -pedantic or
4909          -pedantic-errors is specified.  In the later case, we always want
4910          an error.  In the former case, we simply want a warning.  */
4911       if (require_constant && pedantic
4912           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4913         {
4914           inside_init
4915             = valid_compound_expr_initializer (inside_init,
4916                                                TREE_TYPE (inside_init));
4917           if (inside_init == error_mark_node)
4918             error_init ("initializer element is not constant");
4919           else
4920             pedwarn_init (input_location, OPT_pedantic,
4921                           "initializer element is not constant");
4922           if (flag_pedantic_errors)
4923             inside_init = error_mark_node;
4924         }
4925       else if (require_constant
4926                && !initializer_constant_valid_p (inside_init,
4927                                                  TREE_TYPE (inside_init)))
4928         {
4929           error_init ("initializer element is not constant");
4930           inside_init = error_mark_node;
4931         }
4932
4933       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4934       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4935         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4936                                               NULL_TREE, 0);
4937       return inside_init;
4938     }
4939
4940   /* Handle scalar types, including conversions.  */
4941
4942   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4943       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4944       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4945     {
4946       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4947           && (TREE_CODE (init) == STRING_CST
4948               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4949         init = array_to_pointer_conversion (init);
4950       inside_init
4951         = convert_for_assignment (type, init, ic_init,
4952                                   NULL_TREE, NULL_TREE, 0);
4953
4954       /* Check to see if we have already given an error message.  */
4955       if (inside_init == error_mark_node)
4956         ;
4957       else if (require_constant && !TREE_CONSTANT (inside_init))
4958         {
4959           error_init ("initializer element is not constant");
4960           inside_init = error_mark_node;
4961         }
4962       else if (require_constant
4963                && !initializer_constant_valid_p (inside_init,
4964                                                  TREE_TYPE (inside_init)))
4965         {
4966           error_init ("initializer element is not computable at load time");
4967           inside_init = error_mark_node;
4968         }
4969
4970       return inside_init;
4971     }
4972
4973   /* Come here only for records and arrays.  */
4974
4975   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4976     {
4977       error_init ("variable-sized object may not be initialized");
4978       return error_mark_node;
4979     }
4980
4981   error_init ("invalid initializer");
4982   return error_mark_node;
4983 }
4984 \f
4985 /* Handle initializers that use braces.  */
4986
4987 /* Type of object we are accumulating a constructor for.
4988    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4989 static tree constructor_type;
4990
4991 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4992    left to fill.  */
4993 static tree constructor_fields;
4994
4995 /* For an ARRAY_TYPE, this is the specified index
4996    at which to store the next element we get.  */
4997 static tree constructor_index;
4998
4999 /* For an ARRAY_TYPE, this is the maximum index.  */
5000 static tree constructor_max_index;
5001
5002 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5003 static tree constructor_unfilled_fields;
5004
5005 /* For an ARRAY_TYPE, this is the index of the first element
5006    not yet written out.  */
5007 static tree constructor_unfilled_index;
5008
5009 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5010    This is so we can generate gaps between fields, when appropriate.  */
5011 static tree constructor_bit_index;
5012
5013 /* If we are saving up the elements rather than allocating them,
5014    this is the list of elements so far (in reverse order,
5015    most recent first).  */
5016 static VEC(constructor_elt,gc) *constructor_elements;
5017
5018 /* 1 if constructor should be incrementally stored into a constructor chain,
5019    0 if all the elements should be kept in AVL tree.  */
5020 static int constructor_incremental;
5021
5022 /* 1 if so far this constructor's elements are all compile-time constants.  */
5023 static int constructor_constant;
5024
5025 /* 1 if so far this constructor's elements are all valid address constants.  */
5026 static int constructor_simple;
5027
5028 /* 1 if this constructor is erroneous so far.  */
5029 static int constructor_erroneous;
5030
5031 /* Structure for managing pending initializer elements, organized as an
5032    AVL tree.  */
5033
5034 struct init_node
5035 {
5036   struct init_node *left, *right;
5037   struct init_node *parent;
5038   int balance;
5039   tree purpose;
5040   tree value;
5041 };
5042
5043 /* Tree of pending elements at this constructor level.
5044    These are elements encountered out of order
5045    which belong at places we haven't reached yet in actually
5046    writing the output.
5047    Will never hold tree nodes across GC runs.  */
5048 static struct init_node *constructor_pending_elts;
5049
5050 /* The SPELLING_DEPTH of this constructor.  */
5051 static int constructor_depth;
5052
5053 /* DECL node for which an initializer is being read.
5054    0 means we are reading a constructor expression
5055    such as (struct foo) {...}.  */
5056 static tree constructor_decl;
5057
5058 /* Nonzero if this is an initializer for a top-level decl.  */
5059 static int constructor_top_level;
5060
5061 /* Nonzero if there were any member designators in this initializer.  */
5062 static int constructor_designated;
5063
5064 /* Nesting depth of designator list.  */
5065 static int designator_depth;
5066
5067 /* Nonzero if there were diagnosed errors in this designator list.  */
5068 static int designator_erroneous;
5069
5070 \f
5071 /* This stack has a level for each implicit or explicit level of
5072    structuring in the initializer, including the outermost one.  It
5073    saves the values of most of the variables above.  */
5074
5075 struct constructor_range_stack;
5076
5077 struct constructor_stack
5078 {
5079   struct constructor_stack *next;
5080   tree type;
5081   tree fields;
5082   tree index;
5083   tree max_index;
5084   tree unfilled_index;
5085   tree unfilled_fields;
5086   tree bit_index;
5087   VEC(constructor_elt,gc) *elements;
5088   struct init_node *pending_elts;
5089   int offset;
5090   int depth;
5091   /* If value nonzero, this value should replace the entire
5092      constructor at this level.  */
5093   struct c_expr replacement_value;
5094   struct constructor_range_stack *range_stack;
5095   char constant;
5096   char simple;
5097   char implicit;
5098   char erroneous;
5099   char outer;
5100   char incremental;
5101   char designated;
5102 };
5103
5104 static struct constructor_stack *constructor_stack;
5105
5106 /* This stack represents designators from some range designator up to
5107    the last designator in the list.  */
5108
5109 struct constructor_range_stack
5110 {
5111   struct constructor_range_stack *next, *prev;
5112   struct constructor_stack *stack;
5113   tree range_start;
5114   tree index;
5115   tree range_end;
5116   tree fields;
5117 };
5118
5119 static struct constructor_range_stack *constructor_range_stack;
5120
5121 /* This stack records separate initializers that are nested.
5122    Nested initializers can't happen in ANSI C, but GNU C allows them
5123    in cases like { ... (struct foo) { ... } ... }.  */
5124
5125 struct initializer_stack
5126 {
5127   struct initializer_stack *next;
5128   tree decl;
5129   struct constructor_stack *constructor_stack;
5130   struct constructor_range_stack *constructor_range_stack;
5131   VEC(constructor_elt,gc) *elements;
5132   struct spelling *spelling;
5133   struct spelling *spelling_base;
5134   int spelling_size;
5135   char top_level;
5136   char require_constant_value;
5137   char require_constant_elements;
5138 };
5139
5140 static struct initializer_stack *initializer_stack;
5141 \f
5142 /* Prepare to parse and output the initializer for variable DECL.  */
5143
5144 void
5145 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5146 {
5147   const char *locus;
5148   struct initializer_stack *p = XNEW (struct initializer_stack);
5149
5150   p->decl = constructor_decl;
5151   p->require_constant_value = require_constant_value;
5152   p->require_constant_elements = require_constant_elements;
5153   p->constructor_stack = constructor_stack;
5154   p->constructor_range_stack = constructor_range_stack;
5155   p->elements = constructor_elements;
5156   p->spelling = spelling;
5157   p->spelling_base = spelling_base;
5158   p->spelling_size = spelling_size;
5159   p->top_level = constructor_top_level;
5160   p->next = initializer_stack;
5161   initializer_stack = p;
5162
5163   constructor_decl = decl;
5164   constructor_designated = 0;
5165   constructor_top_level = top_level;
5166
5167   if (decl != 0 && decl != error_mark_node)
5168     {
5169       require_constant_value = TREE_STATIC (decl);
5170       require_constant_elements
5171         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5172            /* For a scalar, you can always use any value to initialize,
5173               even within braces.  */
5174            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5175                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5176                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5177                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5178       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5179     }
5180   else
5181     {
5182       require_constant_value = 0;
5183       require_constant_elements = 0;
5184       locus = "(anonymous)";
5185     }
5186
5187   constructor_stack = 0;
5188   constructor_range_stack = 0;
5189
5190   missing_braces_mentioned = 0;
5191
5192   spelling_base = 0;
5193   spelling_size = 0;
5194   RESTORE_SPELLING_DEPTH (0);
5195
5196   if (locus)
5197     push_string (locus);
5198 }
5199
5200 void
5201 finish_init (void)
5202 {
5203   struct initializer_stack *p = initializer_stack;
5204
5205   /* Free the whole constructor stack of this initializer.  */
5206   while (constructor_stack)
5207     {
5208       struct constructor_stack *q = constructor_stack;
5209       constructor_stack = q->next;
5210       free (q);
5211     }
5212
5213   gcc_assert (!constructor_range_stack);
5214
5215   /* Pop back to the data of the outer initializer (if any).  */
5216   free (spelling_base);
5217
5218   constructor_decl = p->decl;
5219   require_constant_value = p->require_constant_value;
5220   require_constant_elements = p->require_constant_elements;
5221   constructor_stack = p->constructor_stack;
5222   constructor_range_stack = p->constructor_range_stack;
5223   constructor_elements = p->elements;
5224   spelling = p->spelling;
5225   spelling_base = p->spelling_base;
5226   spelling_size = p->spelling_size;
5227   constructor_top_level = p->top_level;
5228   initializer_stack = p->next;
5229   free (p);
5230 }
5231 \f
5232 /* Call here when we see the initializer is surrounded by braces.
5233    This is instead of a call to push_init_level;
5234    it is matched by a call to pop_init_level.
5235
5236    TYPE is the type to initialize, for a constructor expression.
5237    For an initializer for a decl, TYPE is zero.  */
5238
5239 void
5240 really_start_incremental_init (tree type)
5241 {
5242   struct constructor_stack *p = XNEW (struct constructor_stack);
5243
5244   if (type == 0)
5245     type = TREE_TYPE (constructor_decl);
5246
5247   if (targetm.vector_opaque_p (type))
5248     error ("opaque vector types cannot be initialized");
5249
5250   p->type = constructor_type;
5251   p->fields = constructor_fields;
5252   p->index = constructor_index;
5253   p->max_index = constructor_max_index;
5254   p->unfilled_index = constructor_unfilled_index;
5255   p->unfilled_fields = constructor_unfilled_fields;
5256   p->bit_index = constructor_bit_index;
5257   p->elements = constructor_elements;
5258   p->constant = constructor_constant;
5259   p->simple = constructor_simple;
5260   p->erroneous = constructor_erroneous;
5261   p->pending_elts = constructor_pending_elts;
5262   p->depth = constructor_depth;
5263   p->replacement_value.value = 0;
5264   p->replacement_value.original_code = ERROR_MARK;
5265   p->implicit = 0;
5266   p->range_stack = 0;
5267   p->outer = 0;
5268   p->incremental = constructor_incremental;
5269   p->designated = constructor_designated;
5270   p->next = 0;
5271   constructor_stack = p;
5272
5273   constructor_constant = 1;
5274   constructor_simple = 1;
5275   constructor_depth = SPELLING_DEPTH ();
5276   constructor_elements = 0;
5277   constructor_pending_elts = 0;
5278   constructor_type = type;
5279   constructor_incremental = 1;
5280   constructor_designated = 0;
5281   designator_depth = 0;
5282   designator_erroneous = 0;
5283
5284   if (TREE_CODE (constructor_type) == RECORD_TYPE
5285       || TREE_CODE (constructor_type) == UNION_TYPE)
5286     {
5287       constructor_fields = TYPE_FIELDS (constructor_type);
5288       /* Skip any nameless bit fields at the beginning.  */
5289       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5290              && DECL_NAME (constructor_fields) == 0)
5291         constructor_fields = TREE_CHAIN (constructor_fields);
5292
5293       constructor_unfilled_fields = constructor_fields;
5294       constructor_bit_index = bitsize_zero_node;
5295     }
5296   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5297     {
5298       if (TYPE_DOMAIN (constructor_type))
5299         {
5300           constructor_max_index
5301             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5302
5303           /* Detect non-empty initializations of zero-length arrays.  */
5304           if (constructor_max_index == NULL_TREE
5305               && TYPE_SIZE (constructor_type))
5306             constructor_max_index = build_int_cst (NULL_TREE, -1);
5307
5308           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5309              to initialize VLAs will cause a proper error; avoid tree
5310              checking errors as well by setting a safe value.  */
5311           if (constructor_max_index
5312               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5313             constructor_max_index = build_int_cst (NULL_TREE, -1);
5314
5315           constructor_index
5316             = convert (bitsizetype,
5317                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5318         }
5319       else
5320         {
5321           constructor_index = bitsize_zero_node;
5322           constructor_max_index = NULL_TREE;
5323         }
5324
5325       constructor_unfilled_index = constructor_index;
5326     }
5327   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5328     {
5329       /* Vectors are like simple fixed-size arrays.  */
5330       constructor_max_index =
5331         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5332       constructor_index = bitsize_zero_node;
5333       constructor_unfilled_index = constructor_index;
5334     }
5335   else
5336     {
5337       /* Handle the case of int x = {5}; */
5338       constructor_fields = constructor_type;
5339       constructor_unfilled_fields = constructor_type;
5340     }
5341 }
5342 \f
5343 /* Push down into a subobject, for initialization.
5344    If this is for an explicit set of braces, IMPLICIT is 0.
5345    If it is because the next element belongs at a lower level,
5346    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5347
5348 void
5349 push_init_level (int implicit)
5350 {
5351   struct constructor_stack *p;
5352   tree value = NULL_TREE;
5353
5354   /* If we've exhausted any levels that didn't have braces,
5355      pop them now.  If implicit == 1, this will have been done in
5356      process_init_element; do not repeat it here because in the case
5357      of excess initializers for an empty aggregate this leads to an
5358      infinite cycle of popping a level and immediately recreating
5359      it.  */
5360   if (implicit != 1)
5361     {
5362       while (constructor_stack->implicit)
5363         {
5364           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5365                || TREE_CODE (constructor_type) == UNION_TYPE)
5366               && constructor_fields == 0)
5367             process_init_element (pop_init_level (1));
5368           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5369                    && constructor_max_index
5370                    && tree_int_cst_lt (constructor_max_index,
5371                                        constructor_index))
5372             process_init_element (pop_init_level (1));
5373           else
5374             break;
5375         }
5376     }
5377
5378   /* Unless this is an explicit brace, we need to preserve previous
5379      content if any.  */
5380   if (implicit)
5381     {
5382       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5383            || TREE_CODE (constructor_type) == UNION_TYPE)
5384           && constructor_fields)
5385         value = find_init_member (constructor_fields);
5386       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5387         value = find_init_member (constructor_index);
5388     }
5389
5390   p = XNEW (struct constructor_stack);
5391   p->type = constructor_type;
5392   p->fields = constructor_fields;
5393   p->index = constructor_index;
5394   p->max_index = constructor_max_index;
5395   p->unfilled_index = constructor_unfilled_index;
5396   p->unfilled_fields = constructor_unfilled_fields;
5397   p->bit_index = constructor_bit_index;
5398   p->elements = constructor_elements;
5399   p->constant = constructor_constant;
5400   p->simple = constructor_simple;
5401   p->erroneous = constructor_erroneous;
5402   p->pending_elts = constructor_pending_elts;
5403   p->depth = constructor_depth;
5404   p->replacement_value.value = 0;
5405   p->replacement_value.original_code = ERROR_MARK;
5406   p->implicit = implicit;
5407   p->outer = 0;
5408   p->incremental = constructor_incremental;
5409   p->designated = constructor_designated;
5410   p->next = constructor_stack;
5411   p->range_stack = 0;
5412   constructor_stack = p;
5413
5414   constructor_constant = 1;
5415   constructor_simple = 1;
5416   constructor_depth = SPELLING_DEPTH ();
5417   constructor_elements = 0;
5418   constructor_incremental = 1;
5419   constructor_designated = 0;
5420   constructor_pending_elts = 0;
5421   if (!implicit)
5422     {
5423       p->range_stack = constructor_range_stack;
5424       constructor_range_stack = 0;
5425       designator_depth = 0;
5426       designator_erroneous = 0;
5427     }
5428
5429   /* Don't die if an entire brace-pair level is superfluous
5430      in the containing level.  */
5431   if (constructor_type == 0)
5432     ;
5433   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5434            || TREE_CODE (constructor_type) == UNION_TYPE)
5435     {
5436       /* Don't die if there are extra init elts at the end.  */
5437       if (constructor_fields == 0)
5438         constructor_type = 0;
5439       else
5440         {
5441           constructor_type = TREE_TYPE (constructor_fields);
5442           push_member_name (constructor_fields);
5443           constructor_depth++;
5444         }
5445     }
5446   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5447     {
5448       constructor_type = TREE_TYPE (constructor_type);
5449       push_array_bounds (tree_low_cst (constructor_index, 1));
5450       constructor_depth++;
5451     }
5452
5453   if (constructor_type == 0)
5454     {
5455       error_init ("extra brace group at end of initializer");
5456       constructor_fields = 0;
5457       constructor_unfilled_fields = 0;
5458       return;
5459     }
5460
5461   if (value && TREE_CODE (value) == CONSTRUCTOR)
5462     {
5463       constructor_constant = TREE_CONSTANT (value);
5464       constructor_simple = TREE_STATIC (value);
5465       constructor_elements = CONSTRUCTOR_ELTS (value);
5466       if (!VEC_empty (constructor_elt, constructor_elements)
5467           && (TREE_CODE (constructor_type) == RECORD_TYPE
5468               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5469         set_nonincremental_init ();
5470     }
5471
5472   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5473     {
5474       missing_braces_mentioned = 1;
5475       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5476     }
5477
5478   if (TREE_CODE (constructor_type) == RECORD_TYPE
5479            || TREE_CODE (constructor_type) == UNION_TYPE)
5480     {
5481       constructor_fields = TYPE_FIELDS (constructor_type);
5482       /* Skip any nameless bit fields at the beginning.  */
5483       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5484              && DECL_NAME (constructor_fields) == 0)
5485         constructor_fields = TREE_CHAIN (constructor_fields);
5486
5487       constructor_unfilled_fields = constructor_fields;
5488       constructor_bit_index = bitsize_zero_node;
5489     }
5490   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5491     {
5492       /* Vectors are like simple fixed-size arrays.  */
5493       constructor_max_index =
5494         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5495       constructor_index = convert (bitsizetype, integer_zero_node);
5496       constructor_unfilled_index = constructor_index;
5497     }
5498   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5499     {
5500       if (TYPE_DOMAIN (constructor_type))
5501         {
5502           constructor_max_index
5503             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5504
5505           /* Detect non-empty initializations of zero-length arrays.  */
5506           if (constructor_max_index == NULL_TREE
5507               && TYPE_SIZE (constructor_type))
5508             constructor_max_index = build_int_cst (NULL_TREE, -1);
5509
5510           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5511              to initialize VLAs will cause a proper error; avoid tree
5512              checking errors as well by setting a safe value.  */
5513           if (constructor_max_index
5514               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5515             constructor_max_index = build_int_cst (NULL_TREE, -1);
5516
5517           constructor_index
5518             = convert (bitsizetype,
5519                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5520         }
5521       else
5522         constructor_index = bitsize_zero_node;
5523
5524       constructor_unfilled_index = constructor_index;
5525       if (value && TREE_CODE (value) == STRING_CST)
5526         {
5527           /* We need to split the char/wchar array into individual
5528              characters, so that we don't have to special case it
5529              everywhere.  */
5530           set_nonincremental_init_from_string (value);
5531         }
5532     }
5533   else
5534     {
5535       if (constructor_type != error_mark_node)
5536         warning_init (0, "braces around scalar initializer");
5537       constructor_fields = constructor_type;
5538       constructor_unfilled_fields = constructor_type;
5539     }
5540 }
5541
5542 /* At the end of an implicit or explicit brace level,
5543    finish up that level of constructor.  If a single expression
5544    with redundant braces initialized that level, return the
5545    c_expr structure for that expression.  Otherwise, the original_code
5546    element is set to ERROR_MARK.
5547    If we were outputting the elements as they are read, return 0 as the value
5548    from inner levels (process_init_element ignores that),
5549    but return error_mark_node as the value from the outermost level
5550    (that's what we want to put in DECL_INITIAL).
5551    Otherwise, return a CONSTRUCTOR expression as the value.  */
5552
5553 struct c_expr
5554 pop_init_level (int implicit)
5555 {
5556   struct constructor_stack *p;
5557   struct c_expr ret;
5558   ret.value = 0;
5559   ret.original_code = ERROR_MARK;
5560
5561   if (implicit == 0)
5562     {
5563       /* When we come to an explicit close brace,
5564          pop any inner levels that didn't have explicit braces.  */
5565       while (constructor_stack->implicit)
5566         process_init_element (pop_init_level (1));
5567
5568       gcc_assert (!constructor_range_stack);
5569     }
5570
5571   /* Now output all pending elements.  */
5572   constructor_incremental = 1;
5573   output_pending_init_elements (1);
5574
5575   p = constructor_stack;
5576
5577   /* Error for initializing a flexible array member, or a zero-length
5578      array member in an inappropriate context.  */
5579   if (constructor_type && constructor_fields
5580       && TREE_CODE (constructor_type) == ARRAY_TYPE
5581       && TYPE_DOMAIN (constructor_type)
5582       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5583     {
5584       /* Silently discard empty initializations.  The parser will
5585          already have pedwarned for empty brackets.  */
5586       if (integer_zerop (constructor_unfilled_index))
5587         constructor_type = NULL_TREE;
5588       else
5589         {
5590           gcc_assert (!TYPE_SIZE (constructor_type));
5591
5592           if (constructor_depth > 2)
5593             error_init ("initialization of flexible array member in a nested context");
5594           else
5595             pedwarn_init (input_location, OPT_pedantic,
5596                           "initialization of a flexible array member");
5597
5598           /* We have already issued an error message for the existence
5599              of a flexible array member not at the end of the structure.
5600              Discard the initializer so that we do not die later.  */
5601           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5602             constructor_type = NULL_TREE;
5603         }
5604     }
5605
5606   /* Warn when some struct elements are implicitly initialized to zero.  */
5607   if (warn_missing_field_initializers
5608       && constructor_type
5609       && TREE_CODE (constructor_type) == RECORD_TYPE
5610       && constructor_unfilled_fields)
5611     {
5612         /* Do not warn for flexible array members or zero-length arrays.  */
5613         while (constructor_unfilled_fields
5614                && (!DECL_SIZE (constructor_unfilled_fields)
5615                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5616           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5617
5618         /* Do not warn if this level of the initializer uses member
5619            designators; it is likely to be deliberate.  */
5620         if (constructor_unfilled_fields && !constructor_designated)
5621           {
5622             push_member_name (constructor_unfilled_fields);
5623             warning_init (OPT_Wmissing_field_initializers,
5624                           "missing initializer");
5625             RESTORE_SPELLING_DEPTH (constructor_depth);
5626           }
5627     }
5628
5629   /* Pad out the end of the structure.  */
5630   if (p->replacement_value.value)
5631     /* If this closes a superfluous brace pair,
5632        just pass out the element between them.  */
5633     ret = p->replacement_value;
5634   else if (constructor_type == 0)
5635     ;
5636   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5637            && TREE_CODE (constructor_type) != UNION_TYPE
5638            && TREE_CODE (constructor_type) != ARRAY_TYPE
5639            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5640     {
5641       /* A nonincremental scalar initializer--just return
5642          the element, after verifying there is just one.  */
5643       if (VEC_empty (constructor_elt,constructor_elements))
5644         {
5645           if (!constructor_erroneous)
5646             error_init ("empty scalar initializer");
5647           ret.value = error_mark_node;
5648         }
5649       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5650         {
5651           error_init ("extra elements in scalar initializer");
5652           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5653         }
5654       else
5655         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5656     }
5657   else
5658     {
5659       if (constructor_erroneous)
5660         ret.value = error_mark_node;
5661       else
5662         {
5663           ret.value = build_constructor (constructor_type,
5664                                          constructor_elements);
5665           if (constructor_constant)
5666             TREE_CONSTANT (ret.value) = 1;
5667           if (constructor_constant && constructor_simple)
5668             TREE_STATIC (ret.value) = 1;
5669         }
5670     }
5671
5672   constructor_type = p->type;
5673   constructor_fields = p->fields;
5674   constructor_index = p->index;
5675   constructor_max_index = p->max_index;
5676   constructor_unfilled_index = p->unfilled_index;
5677   constructor_unfilled_fields = p->unfilled_fields;
5678   constructor_bit_index = p->bit_index;
5679   constructor_elements = p->elements;
5680   constructor_constant = p->constant;
5681   constructor_simple = p->simple;
5682   constructor_erroneous = p->erroneous;
5683   constructor_incremental = p->incremental;
5684   constructor_designated = p->designated;
5685   constructor_pending_elts = p->pending_elts;
5686   constructor_depth = p->depth;
5687   if (!p->implicit)
5688     constructor_range_stack = p->range_stack;
5689   RESTORE_SPELLING_DEPTH (constructor_depth);
5690
5691   constructor_stack = p->next;
5692   free (p);
5693
5694   if (ret.value == 0 && constructor_stack == 0)
5695     ret.value = error_mark_node;
5696   return ret;
5697 }
5698
5699 /* Common handling for both array range and field name designators.
5700    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5701
5702 static int
5703 set_designator (int array)
5704 {
5705   tree subtype;
5706   enum tree_code subcode;
5707
5708   /* Don't die if an entire brace-pair level is superfluous
5709      in the containing level.  */
5710   if (constructor_type == 0)
5711     return 1;
5712
5713   /* If there were errors in this designator list already, bail out
5714      silently.  */
5715   if (designator_erroneous)
5716     return 1;
5717
5718   if (!designator_depth)
5719     {
5720       gcc_assert (!constructor_range_stack);
5721
5722       /* Designator list starts at the level of closest explicit
5723          braces.  */
5724       while (constructor_stack->implicit)
5725         process_init_element (pop_init_level (1));
5726       constructor_designated = 1;
5727       return 0;
5728     }
5729
5730   switch (TREE_CODE (constructor_type))
5731     {
5732     case  RECORD_TYPE:
5733     case  UNION_TYPE:
5734       subtype = TREE_TYPE (constructor_fields);
5735       if (subtype != error_mark_node)
5736         subtype = TYPE_MAIN_VARIANT (subtype);
5737       break;
5738     case ARRAY_TYPE:
5739       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5740       break;
5741     default:
5742       gcc_unreachable ();
5743     }
5744
5745   subcode = TREE_CODE (subtype);
5746   if (array && subcode != ARRAY_TYPE)
5747     {
5748       error_init ("array index in non-array initializer");
5749       return 1;
5750     }
5751   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5752     {
5753       error_init ("field name not in record or union initializer");
5754       return 1;
5755     }
5756
5757   constructor_designated = 1;
5758   push_init_level (2);
5759   return 0;
5760 }
5761
5762 /* If there are range designators in designator list, push a new designator
5763    to constructor_range_stack.  RANGE_END is end of such stack range or
5764    NULL_TREE if there is no range designator at this level.  */
5765
5766 static void
5767 push_range_stack (tree range_end)
5768 {
5769   struct constructor_range_stack *p;
5770
5771   p = GGC_NEW (struct constructor_range_stack);
5772   p->prev = constructor_range_stack;
5773   p->next = 0;
5774   p->fields = constructor_fields;
5775   p->range_start = constructor_index;
5776   p->index = constructor_index;
5777   p->stack = constructor_stack;
5778   p->range_end = range_end;
5779   if (constructor_range_stack)
5780     constructor_range_stack->next = p;
5781   constructor_range_stack = p;
5782 }
5783
5784 /* Within an array initializer, specify the next index to be initialized.
5785    FIRST is that index.  If LAST is nonzero, then initialize a range
5786    of indices, running from FIRST through LAST.  */
5787
5788 void
5789 set_init_index (tree first, tree last)
5790 {
5791   if (set_designator (1))
5792     return;
5793
5794   designator_erroneous = 1;
5795
5796   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5797       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5798     {
5799       error_init ("array index in initializer not of integer type");
5800       return;
5801     }
5802
5803   if (TREE_CODE (first) != INTEGER_CST)
5804     error_init ("nonconstant array index in initializer");
5805   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5806     error_init ("nonconstant array index in initializer");
5807   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5808     error_init ("array index in non-array initializer");
5809   else if (tree_int_cst_sgn (first) == -1)
5810     error_init ("array index in initializer exceeds array bounds");
5811   else if (constructor_max_index
5812            && tree_int_cst_lt (constructor_max_index, first))
5813     error_init ("array index in initializer exceeds array bounds");
5814   else
5815     {
5816       constructor_index = convert (bitsizetype, first);
5817
5818       if (last)
5819         {
5820           if (tree_int_cst_equal (first, last))
5821             last = 0;
5822           else if (tree_int_cst_lt (last, first))
5823             {
5824               error_init ("empty index range in initializer");
5825               last = 0;
5826             }
5827           else
5828             {
5829               last = convert (bitsizetype, last);
5830               if (constructor_max_index != 0
5831                   && tree_int_cst_lt (constructor_max_index, last))
5832                 {
5833                   error_init ("array index range in initializer exceeds array bounds");
5834                   last = 0;
5835                 }
5836             }
5837         }
5838
5839       designator_depth++;
5840       designator_erroneous = 0;
5841       if (constructor_range_stack || last)
5842         push_range_stack (last);
5843     }
5844 }
5845
5846 /* Within a struct initializer, specify the next field to be initialized.  */
5847
5848 void
5849 set_init_label (tree fieldname)
5850 {
5851   tree tail;
5852
5853   if (set_designator (0))
5854     return;
5855
5856   designator_erroneous = 1;
5857
5858   if (TREE_CODE (constructor_type) != RECORD_TYPE
5859       && TREE_CODE (constructor_type) != UNION_TYPE)
5860     {
5861       error_init ("field name not in record or union initializer");
5862       return;
5863     }
5864
5865   for (tail = TYPE_FIELDS (constructor_type); tail;
5866        tail = TREE_CHAIN (tail))
5867     {
5868       if (DECL_NAME (tail) == fieldname)
5869         break;
5870     }
5871
5872   if (tail == 0)
5873     error ("unknown field %qE specified in initializer", fieldname);
5874   else
5875     {
5876       constructor_fields = tail;
5877       designator_depth++;
5878       designator_erroneous = 0;
5879       if (constructor_range_stack)
5880         push_range_stack (NULL_TREE);
5881     }
5882 }
5883 \f
5884 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5885    identifies the initializer, either array index or field in a structure.
5886    VALUE is the value of that index or field.  */
5887
5888 static void
5889 add_pending_init (tree purpose, tree value)
5890 {
5891   struct init_node *p, **q, *r;
5892
5893   q = &constructor_pending_elts;
5894   p = 0;
5895
5896   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5897     {
5898       while (*q != 0)
5899         {
5900           p = *q;
5901           if (tree_int_cst_lt (purpose, p->purpose))
5902             q = &p->left;
5903           else if (tree_int_cst_lt (p->purpose, purpose))
5904             q = &p->right;
5905           else
5906             {
5907               if (TREE_SIDE_EFFECTS (p->value))
5908                 warning_init (0, "initialized field with side-effects overwritten");
5909               else if (warn_override_init)
5910                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5911               p->value = value;
5912               return;
5913             }
5914         }
5915     }
5916   else
5917     {
5918       tree bitpos;
5919
5920       bitpos = bit_position (purpose);
5921       while (*q != NULL)
5922         {
5923           p = *q;
5924           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5925             q = &p->left;
5926           else if (p->purpose != purpose)
5927             q = &p->right;
5928           else
5929             {
5930               if (TREE_SIDE_EFFECTS (p->value))
5931                 warning_init (0, "initialized field with side-effects overwritten");
5932               else if (warn_override_init)
5933                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5934               p->value = value;
5935               return;
5936             }
5937         }
5938     }
5939
5940   r = GGC_NEW (struct init_node);
5941   r->purpose = purpose;
5942   r->value = value;
5943
5944   *q = r;
5945   r->parent = p;
5946   r->left = 0;
5947   r->right = 0;
5948   r->balance = 0;
5949
5950   while (p)
5951     {
5952       struct init_node *s;
5953
5954       if (r == p->left)
5955         {
5956           if (p->balance == 0)
5957             p->balance = -1;
5958           else if (p->balance < 0)
5959             {
5960               if (r->balance < 0)
5961                 {
5962                   /* L rotation.  */
5963                   p->left = r->right;
5964                   if (p->left)
5965                     p->left->parent = p;
5966                   r->right = p;
5967
5968                   p->balance = 0;
5969                   r->balance = 0;
5970
5971                   s = p->parent;
5972                   p->parent = r;
5973                   r->parent = s;
5974                   if (s)
5975                     {
5976                       if (s->left == p)
5977                         s->left = r;
5978                       else
5979                         s->right = r;
5980                     }
5981                   else
5982                     constructor_pending_elts = r;
5983                 }
5984               else
5985                 {
5986                   /* LR rotation.  */
5987                   struct init_node *t = r->right;
5988
5989                   r->right = t->left;
5990                   if (r->right)
5991                     r->right->parent = r;
5992                   t->left = r;
5993
5994                   p->left = t->right;
5995                   if (p->left)
5996                     p->left->parent = p;
5997                   t->right = p;
5998
5999                   p->balance = t->balance < 0;
6000                   r->balance = -(t->balance > 0);
6001                   t->balance = 0;
6002
6003                   s = p->parent;
6004                   p->parent = t;
6005                   r->parent = t;
6006                   t->parent = s;
6007                   if (s)
6008                     {
6009                       if (s->left == p)
6010                         s->left = t;
6011                       else
6012                         s->right = t;
6013                     }
6014                   else
6015                     constructor_pending_elts = t;
6016                 }
6017               break;
6018             }
6019           else
6020             {
6021               /* p->balance == +1; growth of left side balances the node.  */
6022               p->balance = 0;
6023               break;
6024             }
6025         }
6026       else /* r == p->right */
6027         {
6028           if (p->balance == 0)
6029             /* Growth propagation from right side.  */
6030             p->balance++;
6031           else if (p->balance > 0)
6032             {
6033               if (r->balance > 0)
6034                 {
6035                   /* R rotation.  */
6036                   p->right = r->left;
6037                   if (p->right)
6038                     p->right->parent = p;
6039                   r->left = p;
6040
6041                   p->balance = 0;
6042                   r->balance = 0;
6043
6044                   s = p->parent;
6045                   p->parent = r;
6046                   r->parent = s;
6047                   if (s)
6048                     {
6049                       if (s->left == p)
6050                         s->left = r;
6051                       else
6052                         s->right = r;
6053                     }
6054                   else
6055                     constructor_pending_elts = r;
6056                 }
6057               else /* r->balance == -1 */
6058                 {
6059                   /* RL rotation */
6060                   struct init_node *t = r->left;
6061
6062                   r->left = t->right;
6063                   if (r->left)
6064                     r->left->parent = r;
6065                   t->right = r;
6066
6067                   p->right = t->left;
6068                   if (p->right)
6069                     p->right->parent = p;
6070                   t->left = p;
6071
6072                   r->balance = (t->balance < 0);
6073                   p->balance = -(t->balance > 0);
6074                   t->balance = 0;
6075
6076                   s = p->parent;
6077                   p->parent = t;
6078                   r->parent = t;
6079                   t->parent = s;
6080                   if (s)
6081                     {
6082                       if (s->left == p)
6083                         s->left = t;
6084                       else
6085                         s->right = t;
6086                     }
6087                   else
6088                     constructor_pending_elts = t;
6089                 }
6090               break;
6091             }
6092           else
6093             {
6094               /* p->balance == -1; growth of right side balances the node.  */
6095               p->balance = 0;
6096               break;
6097             }
6098         }
6099
6100       r = p;
6101       p = p->parent;
6102     }
6103 }
6104
6105 /* Build AVL tree from a sorted chain.  */
6106
6107 static void
6108 set_nonincremental_init (void)
6109 {
6110   unsigned HOST_WIDE_INT ix;
6111   tree index, value;
6112
6113   if (TREE_CODE (constructor_type) != RECORD_TYPE
6114       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6115     return;
6116
6117   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6118     add_pending_init (index, value);
6119   constructor_elements = 0;
6120   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6121     {
6122       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6123       /* Skip any nameless bit fields at the beginning.  */
6124       while (constructor_unfilled_fields != 0
6125              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6126              && DECL_NAME (constructor_unfilled_fields) == 0)
6127         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6128
6129     }
6130   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6131     {
6132       if (TYPE_DOMAIN (constructor_type))
6133         constructor_unfilled_index
6134             = convert (bitsizetype,
6135                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6136       else
6137         constructor_unfilled_index = bitsize_zero_node;
6138     }
6139   constructor_incremental = 0;
6140 }
6141
6142 /* Build AVL tree from a string constant.  */
6143
6144 static void
6145 set_nonincremental_init_from_string (tree str)
6146 {
6147   tree value, purpose, type;
6148   HOST_WIDE_INT val[2];
6149   const char *p, *end;
6150   int byte, wchar_bytes, charwidth, bitpos;
6151
6152   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6153
6154   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6155   charwidth = TYPE_PRECISION (char_type_node);
6156   type = TREE_TYPE (constructor_type);
6157   p = TREE_STRING_POINTER (str);
6158   end = p + TREE_STRING_LENGTH (str);
6159
6160   for (purpose = bitsize_zero_node;
6161        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6162        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6163     {
6164       if (wchar_bytes == 1)
6165         {
6166           val[1] = (unsigned char) *p++;
6167           val[0] = 0;
6168         }
6169       else
6170         {
6171           val[0] = 0;
6172           val[1] = 0;
6173           for (byte = 0; byte < wchar_bytes; byte++)
6174             {
6175               if (BYTES_BIG_ENDIAN)
6176                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6177               else
6178                 bitpos = byte * charwidth;
6179               val[bitpos < HOST_BITS_PER_WIDE_INT]
6180                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6181                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6182             }
6183         }
6184
6185       if (!TYPE_UNSIGNED (type))
6186         {
6187           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6188           if (bitpos < HOST_BITS_PER_WIDE_INT)
6189             {
6190               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6191                 {
6192                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6193                   val[0] = -1;
6194                 }
6195             }
6196           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6197             {
6198               if (val[1] < 0)
6199                 val[0] = -1;
6200             }
6201           else if (val[0] & (((HOST_WIDE_INT) 1)
6202                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6203             val[0] |= ((HOST_WIDE_INT) -1)
6204                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6205         }
6206
6207       value = build_int_cst_wide (type, val[1], val[0]);
6208       add_pending_init (purpose, value);
6209     }
6210
6211   constructor_incremental = 0;
6212 }
6213
6214 /* Return value of FIELD in pending initializer or zero if the field was
6215    not initialized yet.  */
6216
6217 static tree
6218 find_init_member (tree field)
6219 {
6220   struct init_node *p;
6221
6222   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6223     {
6224       if (constructor_incremental
6225           && tree_int_cst_lt (field, constructor_unfilled_index))
6226         set_nonincremental_init ();
6227
6228       p = constructor_pending_elts;
6229       while (p)
6230         {
6231           if (tree_int_cst_lt (field, p->purpose))
6232             p = p->left;
6233           else if (tree_int_cst_lt (p->purpose, field))
6234             p = p->right;
6235           else
6236             return p->value;
6237         }
6238     }
6239   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6240     {
6241       tree bitpos = bit_position (field);
6242
6243       if (constructor_incremental
6244           && (!constructor_unfilled_fields
6245               || tree_int_cst_lt (bitpos,
6246                                   bit_position (constructor_unfilled_fields))))
6247         set_nonincremental_init ();
6248
6249       p = constructor_pending_elts;
6250       while (p)
6251         {
6252           if (field == p->purpose)
6253             return p->value;
6254           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6255             p = p->left;
6256           else
6257             p = p->right;
6258         }
6259     }
6260   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6261     {
6262       if (!VEC_empty (constructor_elt, constructor_elements)
6263           && (VEC_last (constructor_elt, constructor_elements)->index
6264               == field))
6265         return VEC_last (constructor_elt, constructor_elements)->value;
6266     }
6267   return 0;
6268 }
6269
6270 /* "Output" the next constructor element.
6271    At top level, really output it to assembler code now.
6272    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6273    TYPE is the data type that the containing data type wants here.
6274    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6275    If VALUE is a string constant, STRICT_STRING is true if it is
6276    unparenthesized or we should not warn here for it being parenthesized.
6277    For other types of VALUE, STRICT_STRING is not used.
6278
6279    PENDING if non-nil means output pending elements that belong
6280    right after this element.  (PENDING is normally 1;
6281    it is 0 while outputting pending elements, to avoid recursion.)  */
6282
6283 static void
6284 output_init_element (tree value, bool strict_string, tree type, tree field,
6285                      int pending)
6286 {
6287   constructor_elt *celt;
6288
6289   if (type == error_mark_node || value == error_mark_node)
6290     {
6291       constructor_erroneous = 1;
6292       return;
6293     }
6294   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6295       && (TREE_CODE (value) == STRING_CST
6296           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6297       && !(TREE_CODE (value) == STRING_CST
6298            && TREE_CODE (type) == ARRAY_TYPE
6299            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6300       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6301                      TYPE_MAIN_VARIANT (type)))
6302     value = array_to_pointer_conversion (value);
6303
6304   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6305       && require_constant_value && !flag_isoc99 && pending)
6306     {
6307       /* As an extension, allow initializing objects with static storage
6308          duration with compound literals (which are then treated just as
6309          the brace enclosed list they contain).  */
6310       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6311       value = DECL_INITIAL (decl);
6312     }
6313
6314   if (value == error_mark_node)
6315     constructor_erroneous = 1;
6316   else if (!TREE_CONSTANT (value))
6317     constructor_constant = 0;
6318   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6319            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6320                 || TREE_CODE (constructor_type) == UNION_TYPE)
6321                && DECL_C_BIT_FIELD (field)
6322                && TREE_CODE (value) != INTEGER_CST))
6323     constructor_simple = 0;
6324
6325   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6326     {
6327       if (require_constant_value)
6328         {
6329           error_init ("initializer element is not constant");
6330           value = error_mark_node;
6331         }
6332       else if (require_constant_elements)
6333         pedwarn (input_location, 0,
6334                  "initializer element is not computable at load time");
6335     }
6336
6337   /* If this field is empty (and not at the end of structure),
6338      don't do anything other than checking the initializer.  */
6339   if (field
6340       && (TREE_TYPE (field) == error_mark_node
6341           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6342               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6343               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6344                   || TREE_CHAIN (field)))))
6345     return;
6346
6347   value = digest_init (type, value, strict_string, require_constant_value);
6348   if (value == error_mark_node)
6349     {
6350       constructor_erroneous = 1;
6351       return;
6352     }
6353
6354   /* If this element doesn't come next in sequence,
6355      put it on constructor_pending_elts.  */
6356   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6357       && (!constructor_incremental
6358           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6359     {
6360       if (constructor_incremental
6361           && tree_int_cst_lt (field, constructor_unfilled_index))
6362         set_nonincremental_init ();
6363
6364       add_pending_init (field, value);
6365       return;
6366     }
6367   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6368            && (!constructor_incremental
6369                || field != constructor_unfilled_fields))
6370     {
6371       /* We do this for records but not for unions.  In a union,
6372          no matter which field is specified, it can be initialized
6373          right away since it starts at the beginning of the union.  */
6374       if (constructor_incremental)
6375         {
6376           if (!constructor_unfilled_fields)
6377             set_nonincremental_init ();
6378           else
6379             {
6380               tree bitpos, unfillpos;
6381
6382               bitpos = bit_position (field);
6383               unfillpos = bit_position (constructor_unfilled_fields);
6384
6385               if (tree_int_cst_lt (bitpos, unfillpos))
6386                 set_nonincremental_init ();
6387             }
6388         }
6389
6390       add_pending_init (field, value);
6391       return;
6392     }
6393   else if (TREE_CODE (constructor_type) == UNION_TYPE
6394            && !VEC_empty (constructor_elt, constructor_elements))
6395     {
6396       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6397                                        constructor_elements)->value))
6398         warning_init (0, "initialized field with side-effects overwritten");
6399       else if (warn_override_init)
6400         warning_init (OPT_Woverride_init, "initialized field overwritten");
6401
6402       /* We can have just one union field set.  */
6403       constructor_elements = 0;
6404     }
6405
6406   /* Otherwise, output this element either to
6407      constructor_elements or to the assembler file.  */
6408
6409   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6410   celt->index = field;
6411   celt->value = value;
6412
6413   /* Advance the variable that indicates sequential elements output.  */
6414   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6415     constructor_unfilled_index
6416       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6417                     bitsize_one_node);
6418   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6419     {
6420       constructor_unfilled_fields
6421         = TREE_CHAIN (constructor_unfilled_fields);
6422
6423       /* Skip any nameless bit fields.  */
6424       while (constructor_unfilled_fields != 0
6425              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6426              && DECL_NAME (constructor_unfilled_fields) == 0)
6427         constructor_unfilled_fields =
6428           TREE_CHAIN (constructor_unfilled_fields);
6429     }
6430   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6431     constructor_unfilled_fields = 0;
6432
6433   /* Now output any pending elements which have become next.  */
6434   if (pending)
6435     output_pending_init_elements (0);
6436 }
6437
6438 /* Output any pending elements which have become next.
6439    As we output elements, constructor_unfilled_{fields,index}
6440    advances, which may cause other elements to become next;
6441    if so, they too are output.
6442
6443    If ALL is 0, we return when there are
6444    no more pending elements to output now.
6445
6446    If ALL is 1, we output space as necessary so that
6447    we can output all the pending elements.  */
6448
6449 static void
6450 output_pending_init_elements (int all)
6451 {
6452   struct init_node *elt = constructor_pending_elts;
6453   tree next;
6454
6455  retry:
6456
6457   /* Look through the whole pending tree.
6458      If we find an element that should be output now,
6459      output it.  Otherwise, set NEXT to the element
6460      that comes first among those still pending.  */
6461
6462   next = 0;
6463   while (elt)
6464     {
6465       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6466         {
6467           if (tree_int_cst_equal (elt->purpose,
6468                                   constructor_unfilled_index))
6469             output_init_element (elt->value, true,
6470                                  TREE_TYPE (constructor_type),
6471                                  constructor_unfilled_index, 0);
6472           else if (tree_int_cst_lt (constructor_unfilled_index,
6473                                     elt->purpose))
6474             {
6475               /* Advance to the next smaller node.  */
6476               if (elt->left)
6477                 elt = elt->left;
6478               else
6479                 {
6480                   /* We have reached the smallest node bigger than the
6481                      current unfilled index.  Fill the space first.  */
6482                   next = elt->purpose;
6483                   break;
6484                 }
6485             }
6486           else
6487             {
6488               /* Advance to the next bigger node.  */
6489               if (elt->right)
6490                 elt = elt->right;
6491               else
6492                 {
6493                   /* We have reached the biggest node in a subtree.  Find
6494                      the parent of it, which is the next bigger node.  */
6495                   while (elt->parent && elt->parent->right == elt)
6496                     elt = elt->parent;
6497                   elt = elt->parent;
6498                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6499                                               elt->purpose))
6500                     {
6501                       next = elt->purpose;
6502                       break;
6503                     }
6504                 }
6505             }
6506         }
6507       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6508                || TREE_CODE (constructor_type) == UNION_TYPE)
6509         {
6510           tree ctor_unfilled_bitpos, elt_bitpos;
6511
6512           /* If the current record is complete we are done.  */
6513           if (constructor_unfilled_fields == 0)
6514             break;
6515
6516           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6517           elt_bitpos = bit_position (elt->purpose);
6518           /* We can't compare fields here because there might be empty
6519              fields in between.  */
6520           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6521             {
6522               constructor_unfilled_fields = elt->purpose;
6523               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6524                                    elt->purpose, 0);
6525             }
6526           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6527             {
6528               /* Advance to the next smaller node.  */
6529               if (elt->left)
6530                 elt = elt->left;
6531               else
6532                 {
6533                   /* We have reached the smallest node bigger than the
6534                      current unfilled field.  Fill the space first.  */
6535                   next = elt->purpose;
6536                   break;
6537                 }
6538             }
6539           else
6540             {
6541               /* Advance to the next bigger node.  */
6542               if (elt->right)
6543                 elt = elt->right;
6544               else
6545                 {
6546                   /* We have reached the biggest node in a subtree.  Find
6547                      the parent of it, which is the next bigger node.  */
6548                   while (elt->parent && elt->parent->right == elt)
6549                     elt = elt->parent;
6550                   elt = elt->parent;
6551                   if (elt
6552                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6553                                            bit_position (elt->purpose))))
6554                     {
6555                       next = elt->purpose;
6556                       break;
6557                     }
6558                 }
6559             }
6560         }
6561     }
6562
6563   /* Ordinarily return, but not if we want to output all
6564      and there are elements left.  */
6565   if (!(all && next != 0))
6566     return;
6567
6568   /* If it's not incremental, just skip over the gap, so that after
6569      jumping to retry we will output the next successive element.  */
6570   if (TREE_CODE (constructor_type) == RECORD_TYPE
6571       || TREE_CODE (constructor_type) == UNION_TYPE)
6572     constructor_unfilled_fields = next;
6573   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6574     constructor_unfilled_index = next;
6575
6576   /* ELT now points to the node in the pending tree with the next
6577      initializer to output.  */
6578   goto retry;
6579 }
6580 \f
6581 /* Add one non-braced element to the current constructor level.
6582    This adjusts the current position within the constructor's type.
6583    This may also start or terminate implicit levels
6584    to handle a partly-braced initializer.
6585
6586    Once this has found the correct level for the new element,
6587    it calls output_init_element.  */
6588
6589 void
6590 process_init_element (struct c_expr value)
6591 {
6592   tree orig_value = value.value;
6593   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6594   bool strict_string = value.original_code == STRING_CST;
6595
6596   designator_depth = 0;
6597   designator_erroneous = 0;
6598
6599   /* Handle superfluous braces around string cst as in
6600      char x[] = {"foo"}; */
6601   if (string_flag
6602       && constructor_type
6603       && TREE_CODE (constructor_type) == ARRAY_TYPE
6604       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6605       && integer_zerop (constructor_unfilled_index))
6606     {
6607       if (constructor_stack->replacement_value.value)
6608         error_init ("excess elements in char array initializer");
6609       constructor_stack->replacement_value = value;
6610       return;
6611     }
6612
6613   if (constructor_stack->replacement_value.value != 0)
6614     {
6615       error_init ("excess elements in struct initializer");
6616       return;
6617     }
6618
6619   /* Ignore elements of a brace group if it is entirely superfluous
6620      and has already been diagnosed.  */
6621   if (constructor_type == 0)
6622     return;
6623
6624   /* If we've exhausted any levels that didn't have braces,
6625      pop them now.  */
6626   while (constructor_stack->implicit)
6627     {
6628       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6629            || TREE_CODE (constructor_type) == UNION_TYPE)
6630           && constructor_fields == 0)
6631         process_init_element (pop_init_level (1));
6632       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6633                && (constructor_max_index == 0
6634                    || tree_int_cst_lt (constructor_max_index,
6635                                        constructor_index)))
6636         process_init_element (pop_init_level (1));
6637       else
6638         break;
6639     }
6640
6641   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6642   if (constructor_range_stack)
6643     {
6644       /* If value is a compound literal and we'll be just using its
6645          content, don't put it into a SAVE_EXPR.  */
6646       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6647           || !require_constant_value
6648           || flag_isoc99)
6649         value.value = save_expr (value.value);
6650     }
6651
6652   while (1)
6653     {
6654       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6655         {
6656           tree fieldtype;
6657           enum tree_code fieldcode;
6658
6659           if (constructor_fields == 0)
6660             {
6661               pedwarn_init (input_location, 0,
6662                             "excess elements in struct initializer");
6663               break;
6664             }
6665
6666           fieldtype = TREE_TYPE (constructor_fields);
6667           if (fieldtype != error_mark_node)
6668             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6669           fieldcode = TREE_CODE (fieldtype);
6670
6671           /* Error for non-static initialization of a flexible array member.  */
6672           if (fieldcode == ARRAY_TYPE
6673               && !require_constant_value
6674               && TYPE_SIZE (fieldtype) == NULL_TREE
6675               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6676             {
6677               error_init ("non-static initialization of a flexible array member");
6678               break;
6679             }
6680
6681           /* Accept a string constant to initialize a subarray.  */
6682           if (value.value != 0
6683               && fieldcode == ARRAY_TYPE
6684               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6685               && string_flag)
6686             value.value = orig_value;
6687           /* Otherwise, if we have come to a subaggregate,
6688              and we don't have an element of its type, push into it.  */
6689           else if (value.value != 0
6690                    && value.value != error_mark_node
6691                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6692                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6693                        || fieldcode == UNION_TYPE))
6694             {
6695               push_init_level (1);
6696               continue;
6697             }
6698
6699           if (value.value)
6700             {
6701               push_member_name (constructor_fields);
6702               output_init_element (value.value, strict_string,
6703                                    fieldtype, constructor_fields, 1);
6704               RESTORE_SPELLING_DEPTH (constructor_depth);
6705             }
6706           else
6707             /* Do the bookkeeping for an element that was
6708                directly output as a constructor.  */
6709             {
6710               /* For a record, keep track of end position of last field.  */
6711               if (DECL_SIZE (constructor_fields))
6712                 constructor_bit_index
6713                   = size_binop (PLUS_EXPR,
6714                                 bit_position (constructor_fields),
6715                                 DECL_SIZE (constructor_fields));
6716
6717               /* If the current field was the first one not yet written out,
6718                  it isn't now, so update.  */
6719               if (constructor_unfilled_fields == constructor_fields)
6720                 {
6721                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6722                   /* Skip any nameless bit fields.  */
6723                   while (constructor_unfilled_fields != 0
6724                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6725                          && DECL_NAME (constructor_unfilled_fields) == 0)
6726                     constructor_unfilled_fields =
6727                       TREE_CHAIN (constructor_unfilled_fields);
6728                 }
6729             }
6730
6731           constructor_fields = TREE_CHAIN (constructor_fields);
6732           /* Skip any nameless bit fields at the beginning.  */
6733           while (constructor_fields != 0
6734                  && DECL_C_BIT_FIELD (constructor_fields)
6735                  && DECL_NAME (constructor_fields) == 0)
6736             constructor_fields = TREE_CHAIN (constructor_fields);
6737         }
6738       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6739         {
6740           tree fieldtype;
6741           enum tree_code fieldcode;
6742
6743           if (constructor_fields == 0)
6744             {
6745               pedwarn_init (input_location, 0,
6746                             "excess elements in union initializer");
6747               break;
6748             }
6749
6750           fieldtype = TREE_TYPE (constructor_fields);
6751           if (fieldtype != error_mark_node)
6752             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6753           fieldcode = TREE_CODE (fieldtype);
6754
6755           /* Warn that traditional C rejects initialization of unions.
6756              We skip the warning if the value is zero.  This is done
6757              under the assumption that the zero initializer in user
6758              code appears conditioned on e.g. __STDC__ to avoid
6759              "missing initializer" warnings and relies on default
6760              initialization to zero in the traditional C case.
6761              We also skip the warning if the initializer is designated,
6762              again on the assumption that this must be conditional on
6763              __STDC__ anyway (and we've already complained about the
6764              member-designator already).  */
6765           if (!in_system_header && !constructor_designated
6766               && !(value.value && (integer_zerop (value.value)
6767                                    || real_zerop (value.value))))
6768             warning (OPT_Wtraditional, "traditional C rejects initialization "
6769                      "of unions");
6770
6771           /* Accept a string constant to initialize a subarray.  */
6772           if (value.value != 0
6773               && fieldcode == ARRAY_TYPE
6774               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6775               && string_flag)
6776             value.value = orig_value;
6777           /* Otherwise, if we have come to a subaggregate,
6778              and we don't have an element of its type, push into it.  */
6779           else if (value.value != 0
6780                    && value.value != error_mark_node
6781                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6782                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6783                        || fieldcode == UNION_TYPE))
6784             {
6785               push_init_level (1);
6786               continue;
6787             }
6788
6789           if (value.value)
6790             {
6791               push_member_name (constructor_fields);
6792               output_init_element (value.value, strict_string,
6793                                    fieldtype, constructor_fields, 1);
6794               RESTORE_SPELLING_DEPTH (constructor_depth);
6795             }
6796           else
6797             /* Do the bookkeeping for an element that was
6798                directly output as a constructor.  */
6799             {
6800               constructor_bit_index = DECL_SIZE (constructor_fields);
6801               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6802             }
6803
6804           constructor_fields = 0;
6805         }
6806       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6807         {
6808           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6809           enum tree_code eltcode = TREE_CODE (elttype);
6810
6811           /* Accept a string constant to initialize a subarray.  */
6812           if (value.value != 0
6813               && eltcode == ARRAY_TYPE
6814               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6815               && string_flag)
6816             value.value = orig_value;
6817           /* Otherwise, if we have come to a subaggregate,
6818              and we don't have an element of its type, push into it.  */
6819           else if (value.value != 0
6820                    && value.value != error_mark_node
6821                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6822                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6823                        || eltcode == UNION_TYPE))
6824             {
6825               push_init_level (1);
6826               continue;
6827             }
6828
6829           if (constructor_max_index != 0
6830               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6831                   || integer_all_onesp (constructor_max_index)))
6832             {
6833               pedwarn_init (input_location, 0,
6834                             "excess elements in array initializer");
6835               break;
6836             }
6837
6838           /* Now output the actual element.  */
6839           if (value.value)
6840             {
6841               push_array_bounds (tree_low_cst (constructor_index, 1));
6842               output_init_element (value.value, strict_string,
6843                                    elttype, constructor_index, 1);
6844               RESTORE_SPELLING_DEPTH (constructor_depth);
6845             }
6846
6847           constructor_index
6848             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6849
6850           if (!value.value)
6851             /* If we are doing the bookkeeping for an element that was
6852                directly output as a constructor, we must update
6853                constructor_unfilled_index.  */
6854             constructor_unfilled_index = constructor_index;
6855         }
6856       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6857         {
6858           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6859
6860          /* Do a basic check of initializer size.  Note that vectors
6861             always have a fixed size derived from their type.  */
6862           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6863             {
6864               pedwarn_init (input_location, 0,
6865                             "excess elements in vector initializer");
6866               break;
6867             }
6868
6869           /* Now output the actual element.  */
6870           if (value.value)
6871             output_init_element (value.value, strict_string,
6872                                  elttype, constructor_index, 1);
6873
6874           constructor_index
6875             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6876
6877           if (!value.value)
6878             /* If we are doing the bookkeeping for an element that was
6879                directly output as a constructor, we must update
6880                constructor_unfilled_index.  */
6881             constructor_unfilled_index = constructor_index;
6882         }
6883
6884       /* Handle the sole element allowed in a braced initializer
6885          for a scalar variable.  */
6886       else if (constructor_type != error_mark_node
6887                && constructor_fields == 0)
6888         {
6889           pedwarn_init (input_location, 0,
6890                         "excess elements in scalar initializer");
6891           break;
6892         }
6893       else
6894         {
6895           if (value.value)
6896             output_init_element (value.value, strict_string,
6897                                  constructor_type, NULL_TREE, 1);
6898           constructor_fields = 0;
6899         }
6900
6901       /* Handle range initializers either at this level or anywhere higher
6902          in the designator stack.  */
6903       if (constructor_range_stack)
6904         {
6905           struct constructor_range_stack *p, *range_stack;
6906           int finish = 0;
6907
6908           range_stack = constructor_range_stack;
6909           constructor_range_stack = 0;
6910           while (constructor_stack != range_stack->stack)
6911             {
6912               gcc_assert (constructor_stack->implicit);
6913               process_init_element (pop_init_level (1));
6914             }
6915           for (p = range_stack;
6916                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6917                p = p->prev)
6918             {
6919               gcc_assert (constructor_stack->implicit);
6920               process_init_element (pop_init_level (1));
6921             }
6922
6923           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6924           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6925             finish = 1;
6926
6927           while (1)
6928             {
6929               constructor_index = p->index;
6930               constructor_fields = p->fields;
6931               if (finish && p->range_end && p->index == p->range_start)
6932                 {
6933                   finish = 0;
6934                   p->prev = 0;
6935                 }
6936               p = p->next;
6937               if (!p)
6938                 break;
6939               push_init_level (2);
6940               p->stack = constructor_stack;
6941               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6942                 p->index = p->range_start;
6943             }
6944
6945           if (!finish)
6946             constructor_range_stack = range_stack;
6947           continue;
6948         }
6949
6950       break;
6951     }
6952
6953   constructor_range_stack = 0;
6954 }
6955 \f
6956 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6957    (guaranteed to be 'volatile' or null) and ARGS (represented using
6958    an ASM_EXPR node).  */
6959 tree
6960 build_asm_stmt (tree cv_qualifier, tree args)
6961 {
6962   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6963     ASM_VOLATILE_P (args) = 1;
6964   return add_stmt (args);
6965 }
6966
6967 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6968    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6969    SIMPLE indicates whether there was anything at all after the
6970    string in the asm expression -- asm("blah") and asm("blah" : )
6971    are subtly different.  We use a ASM_EXPR node to represent this.  */
6972 tree
6973 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6974                 bool simple)
6975 {
6976   tree tail;
6977   tree args;
6978   int i;
6979   const char *constraint;
6980   const char **oconstraints;
6981   bool allows_mem, allows_reg, is_inout;
6982   int ninputs, noutputs;
6983
6984   ninputs = list_length (inputs);
6985   noutputs = list_length (outputs);
6986   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6987
6988   string = resolve_asm_operand_names (string, outputs, inputs);
6989
6990   /* Remove output conversions that change the type but not the mode.  */
6991   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6992     {
6993       tree output = TREE_VALUE (tail);
6994
6995       /* ??? Really, this should not be here.  Users should be using a
6996          proper lvalue, dammit.  But there's a long history of using casts
6997          in the output operands.  In cases like longlong.h, this becomes a
6998          primitive form of typechecking -- if the cast can be removed, then
6999          the output operand had a type of the proper width; otherwise we'll
7000          get an error.  Gross, but ...  */
7001       STRIP_NOPS (output);
7002
7003       if (!lvalue_or_else (output, lv_asm))
7004         output = error_mark_node;
7005
7006       if (output != error_mark_node
7007           && (TREE_READONLY (output)
7008               || TYPE_READONLY (TREE_TYPE (output))
7009               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7010                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7011                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7012         readonly_error (output, lv_asm);
7013
7014       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7015       oconstraints[i] = constraint;
7016
7017       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7018                                    &allows_mem, &allows_reg, &is_inout))
7019         {
7020           /* If the operand is going to end up in memory,
7021              mark it addressable.  */
7022           if (!allows_reg && !c_mark_addressable (output))
7023             output = error_mark_node;
7024         }
7025       else
7026         output = error_mark_node;
7027
7028       TREE_VALUE (tail) = output;
7029     }
7030
7031   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7032     {
7033       tree input;
7034
7035       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7036       input = TREE_VALUE (tail);
7037
7038       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7039                                   oconstraints, &allows_mem, &allows_reg))
7040         {
7041           /* If the operand is going to end up in memory,
7042              mark it addressable.  */
7043           if (!allows_reg && allows_mem)
7044             {
7045               /* Strip the nops as we allow this case.  FIXME, this really
7046                  should be rejected or made deprecated.  */
7047               STRIP_NOPS (input);
7048               if (!c_mark_addressable (input))
7049                 input = error_mark_node;
7050           }
7051         }
7052       else
7053         input = error_mark_node;
7054
7055       TREE_VALUE (tail) = input;
7056     }
7057
7058   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7059
7060   /* asm statements without outputs, including simple ones, are treated
7061      as volatile.  */
7062   ASM_INPUT_P (args) = simple;
7063   ASM_VOLATILE_P (args) = (noutputs == 0);
7064
7065   return args;
7066 }
7067 \f
7068 /* Generate a goto statement to LABEL.  */
7069
7070 tree
7071 c_finish_goto_label (tree label)
7072 {
7073   tree decl = lookup_label (label);
7074   if (!decl)
7075     return NULL_TREE;
7076
7077   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7078     {
7079       error ("jump into statement expression");
7080       return NULL_TREE;
7081     }
7082
7083   if (C_DECL_UNJUMPABLE_VM (decl))
7084     {
7085       error ("jump into scope of identifier with variably modified type");
7086       return NULL_TREE;
7087     }
7088
7089   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7090     {
7091       /* No jump from outside this statement expression context, so
7092          record that there is a jump from within this context.  */
7093       struct c_label_list *nlist;
7094       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7095       nlist->next = label_context_stack_se->labels_used;
7096       nlist->label = decl;
7097       label_context_stack_se->labels_used = nlist;
7098     }
7099
7100   if (!C_DECL_UNDEFINABLE_VM (decl))
7101     {
7102       /* No jump from outside this context context of identifiers with
7103          variably modified type, so record that there is a jump from
7104          within this context.  */
7105       struct c_label_list *nlist;
7106       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7107       nlist->next = label_context_stack_vm->labels_used;
7108       nlist->label = decl;
7109       label_context_stack_vm->labels_used = nlist;
7110     }
7111
7112   TREE_USED (decl) = 1;
7113   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7114 }
7115
7116 /* Generate a computed goto statement to EXPR.  */
7117
7118 tree
7119 c_finish_goto_ptr (tree expr)
7120 {
7121   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7122   expr = convert (ptr_type_node, expr);
7123   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7124 }
7125
7126 /* Generate a C `return' statement.  RETVAL is the expression for what
7127    to return, or a null pointer for `return;' with no value.  */
7128
7129 tree
7130 c_finish_return (tree retval)
7131 {
7132   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7133   bool no_warning = false;
7134
7135   if (TREE_THIS_VOLATILE (current_function_decl))
7136     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7137
7138   if (!retval)
7139     {
7140       current_function_returns_null = 1;
7141       if ((warn_return_type || flag_isoc99)
7142           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7143         {
7144           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7145                        "%<return%> with no value, in "
7146                        "function returning non-void");
7147           no_warning = true;
7148         }
7149     }
7150   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7151     {
7152       current_function_returns_null = 1;
7153       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7154         pedwarn (input_location, 0,
7155                  "%<return%> with a value, in function returning void");
7156       else
7157         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7158                  "%<return%> with expression, in function returning void");
7159     }
7160   else
7161     {
7162       tree t = convert_for_assignment (valtype, retval, ic_return,
7163                                        NULL_TREE, NULL_TREE, 0);
7164       tree res = DECL_RESULT (current_function_decl);
7165       tree inner;
7166
7167       current_function_returns_value = 1;
7168       if (t == error_mark_node)
7169         return NULL_TREE;
7170
7171       inner = t = convert (TREE_TYPE (res), t);
7172
7173       /* Strip any conversions, additions, and subtractions, and see if
7174          we are returning the address of a local variable.  Warn if so.  */
7175       while (1)
7176         {
7177           switch (TREE_CODE (inner))
7178             {
7179             CASE_CONVERT:   case NON_LVALUE_EXPR:
7180             case PLUS_EXPR:
7181               inner = TREE_OPERAND (inner, 0);
7182               continue;
7183
7184             case MINUS_EXPR:
7185               /* If the second operand of the MINUS_EXPR has a pointer
7186                  type (or is converted from it), this may be valid, so
7187                  don't give a warning.  */
7188               {
7189                 tree op1 = TREE_OPERAND (inner, 1);
7190
7191                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7192                        && (CONVERT_EXPR_P (op1)
7193                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7194                   op1 = TREE_OPERAND (op1, 0);
7195
7196                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7197                   break;
7198
7199                 inner = TREE_OPERAND (inner, 0);
7200                 continue;
7201               }
7202
7203             case ADDR_EXPR:
7204               inner = TREE_OPERAND (inner, 0);
7205
7206               while (REFERENCE_CLASS_P (inner)
7207                      && TREE_CODE (inner) != INDIRECT_REF)
7208                 inner = TREE_OPERAND (inner, 0);
7209
7210               if (DECL_P (inner)
7211                   && !DECL_EXTERNAL (inner)
7212                   && !TREE_STATIC (inner)
7213                   && DECL_CONTEXT (inner) == current_function_decl)
7214                 warning (0, "function returns address of local variable");
7215               break;
7216
7217             default:
7218               break;
7219             }
7220
7221           break;
7222         }
7223
7224       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7225
7226       if (warn_sequence_point)
7227         verify_sequence_points (retval);
7228     }
7229
7230   ret_stmt = build_stmt (RETURN_EXPR, retval);
7231   TREE_NO_WARNING (ret_stmt) |= no_warning;
7232   return add_stmt (ret_stmt);
7233 }
7234 \f
7235 struct c_switch {
7236   /* The SWITCH_EXPR being built.  */
7237   tree switch_expr;
7238
7239   /* The original type of the testing expression, i.e. before the
7240      default conversion is applied.  */
7241   tree orig_type;
7242
7243   /* A splay-tree mapping the low element of a case range to the high
7244      element, or NULL_TREE if there is no high element.  Used to
7245      determine whether or not a new case label duplicates an old case
7246      label.  We need a tree, rather than simply a hash table, because
7247      of the GNU case range extension.  */
7248   splay_tree cases;
7249
7250   /* Number of nested statement expressions within this switch
7251      statement; if nonzero, case and default labels may not
7252      appear.  */
7253   unsigned int blocked_stmt_expr;
7254
7255   /* Scope of outermost declarations of identifiers with variably
7256      modified type within this switch statement; if nonzero, case and
7257      default labels may not appear.  */
7258   unsigned int blocked_vm;
7259
7260   /* The next node on the stack.  */
7261   struct c_switch *next;
7262 };
7263
7264 /* A stack of the currently active switch statements.  The innermost
7265    switch statement is on the top of the stack.  There is no need to
7266    mark the stack for garbage collection because it is only active
7267    during the processing of the body of a function, and we never
7268    collect at that point.  */
7269
7270 struct c_switch *c_switch_stack;
7271
7272 /* Start a C switch statement, testing expression EXP.  Return the new
7273    SWITCH_EXPR.  */
7274
7275 tree
7276 c_start_case (tree exp)
7277 {
7278   tree orig_type = error_mark_node;
7279   struct c_switch *cs;
7280
7281   if (exp != error_mark_node)
7282     {
7283       orig_type = TREE_TYPE (exp);
7284
7285       if (!INTEGRAL_TYPE_P (orig_type))
7286         {
7287           if (orig_type != error_mark_node)
7288             {
7289               error ("switch quantity not an integer");
7290               orig_type = error_mark_node;
7291             }
7292           exp = integer_zero_node;
7293         }
7294       else
7295         {
7296           tree type = TYPE_MAIN_VARIANT (orig_type);
7297
7298           if (!in_system_header
7299               && (type == long_integer_type_node
7300                   || type == long_unsigned_type_node))
7301             warning (OPT_Wtraditional, "%<long%> switch expression not "
7302                      "converted to %<int%> in ISO C");
7303
7304           exp = default_conversion (exp);
7305
7306           if (warn_sequence_point)
7307             verify_sequence_points (exp);
7308         }
7309     }
7310
7311   /* Add this new SWITCH_EXPR to the stack.  */
7312   cs = XNEW (struct c_switch);
7313   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7314   cs->orig_type = orig_type;
7315   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7316   cs->blocked_stmt_expr = 0;
7317   cs->blocked_vm = 0;
7318   cs->next = c_switch_stack;
7319   c_switch_stack = cs;
7320
7321   return add_stmt (cs->switch_expr);
7322 }
7323
7324 /* Process a case label.  */
7325
7326 tree
7327 do_case (tree low_value, tree high_value)
7328 {
7329   tree label = NULL_TREE;
7330
7331   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7332       && !c_switch_stack->blocked_vm)
7333     {
7334       label = c_add_case_label (c_switch_stack->cases,
7335                                 SWITCH_COND (c_switch_stack->switch_expr),
7336                                 c_switch_stack->orig_type,
7337                                 low_value, high_value);
7338       if (label == error_mark_node)
7339         label = NULL_TREE;
7340     }
7341   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7342     {
7343       if (low_value)
7344         error ("case label in statement expression not containing "
7345                "enclosing switch statement");
7346       else
7347         error ("%<default%> label in statement expression not containing "
7348                "enclosing switch statement");
7349     }
7350   else if (c_switch_stack && c_switch_stack->blocked_vm)
7351     {
7352       if (low_value)
7353         error ("case label in scope of identifier with variably modified "
7354                "type not containing enclosing switch statement");
7355       else
7356         error ("%<default%> label in scope of identifier with variably "
7357                "modified type not containing enclosing switch statement");
7358     }
7359   else if (low_value)
7360     error ("case label not within a switch statement");
7361   else
7362     error ("%<default%> label not within a switch statement");
7363
7364   return label;
7365 }
7366
7367 /* Finish the switch statement.  */
7368
7369 void
7370 c_finish_case (tree body)
7371 {
7372   struct c_switch *cs = c_switch_stack;
7373   location_t switch_location;
7374
7375   SWITCH_BODY (cs->switch_expr) = body;
7376
7377   /* We must not be within a statement expression nested in the switch
7378      at this point; we might, however, be within the scope of an
7379      identifier with variably modified type nested in the switch.  */
7380   gcc_assert (!cs->blocked_stmt_expr);
7381
7382   /* Emit warnings as needed.  */
7383   if (EXPR_HAS_LOCATION (cs->switch_expr))
7384     switch_location = EXPR_LOCATION (cs->switch_expr);
7385   else
7386     switch_location = input_location;
7387   c_do_switch_warnings (cs->cases, switch_location,
7388                         TREE_TYPE (cs->switch_expr),
7389                         SWITCH_COND (cs->switch_expr));
7390
7391   /* Pop the stack.  */
7392   c_switch_stack = cs->next;
7393   splay_tree_delete (cs->cases);
7394   XDELETE (cs);
7395 }
7396 \f
7397 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7398    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7399    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7400    statement, and was not surrounded with parenthesis.  */
7401
7402 void
7403 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7404                   tree else_block, bool nested_if)
7405 {
7406   tree stmt;
7407
7408   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7409   if (warn_parentheses && nested_if && else_block == NULL)
7410     {
7411       tree inner_if = then_block;
7412
7413       /* We know from the grammar productions that there is an IF nested
7414          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7415          it might not be exactly THEN_BLOCK, but should be the last
7416          non-container statement within.  */
7417       while (1)
7418         switch (TREE_CODE (inner_if))
7419           {
7420           case COND_EXPR:
7421             goto found;
7422           case BIND_EXPR:
7423             inner_if = BIND_EXPR_BODY (inner_if);
7424             break;
7425           case STATEMENT_LIST:
7426             inner_if = expr_last (then_block);
7427             break;
7428           case TRY_FINALLY_EXPR:
7429           case TRY_CATCH_EXPR:
7430             inner_if = TREE_OPERAND (inner_if, 0);
7431             break;
7432           default:
7433             gcc_unreachable ();
7434           }
7435     found:
7436
7437       if (COND_EXPR_ELSE (inner_if))
7438          warning (OPT_Wparentheses,
7439                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7440                   &if_locus);
7441     }
7442
7443   empty_if_body_warning (then_block, else_block);
7444
7445   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7446   SET_EXPR_LOCATION (stmt, if_locus);
7447   add_stmt (stmt);
7448 }
7449
7450 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7451    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7452    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7453    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7454    the continue label.  Everything is allowed to be NULL.  */
7455
7456 void
7457 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7458                tree blab, tree clab, bool cond_is_first)
7459 {
7460   tree entry = NULL, exit = NULL, t;
7461
7462   /* If the condition is zero don't generate a loop construct.  */
7463   if (cond && integer_zerop (cond))
7464     {
7465       if (cond_is_first)
7466         {
7467           t = build_and_jump (&blab);
7468           SET_EXPR_LOCATION (t, start_locus);
7469           add_stmt (t);
7470         }
7471     }
7472   else
7473     {
7474       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7475
7476       /* If we have an exit condition, then we build an IF with gotos either
7477          out of the loop, or to the top of it.  If there's no exit condition,
7478          then we just build a jump back to the top.  */
7479       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7480
7481       if (cond && !integer_nonzerop (cond))
7482         {
7483           /* Canonicalize the loop condition to the end.  This means
7484              generating a branch to the loop condition.  Reuse the
7485              continue label, if possible.  */
7486           if (cond_is_first)
7487             {
7488               if (incr || !clab)
7489                 {
7490                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7491                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7492                 }
7493               else
7494                 t = build1 (GOTO_EXPR, void_type_node, clab);
7495               SET_EXPR_LOCATION (t, start_locus);
7496               add_stmt (t);
7497             }
7498
7499           t = build_and_jump (&blab);
7500           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7501           if (cond_is_first)
7502             SET_EXPR_LOCATION (exit, start_locus);
7503           else
7504             SET_EXPR_LOCATION (exit, input_location);
7505         }
7506
7507       add_stmt (top);
7508     }
7509
7510   if (body)
7511     add_stmt (body);
7512   if (clab)
7513     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7514   if (incr)
7515     add_stmt (incr);
7516   if (entry)
7517     add_stmt (entry);
7518   if (exit)
7519     add_stmt (exit);
7520   if (blab)
7521     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7522 }
7523
7524 tree
7525 c_finish_bc_stmt (tree *label_p, bool is_break)
7526 {
7527   bool skip;
7528   tree label = *label_p;
7529
7530   /* In switch statements break is sometimes stylistically used after
7531      a return statement.  This can lead to spurious warnings about
7532      control reaching the end of a non-void function when it is
7533      inlined.  Note that we are calling block_may_fallthru with
7534      language specific tree nodes; this works because
7535      block_may_fallthru returns true when given something it does not
7536      understand.  */
7537   skip = !block_may_fallthru (cur_stmt_list);
7538
7539   if (!label)
7540     {
7541       if (!skip)
7542         *label_p = label = create_artificial_label ();
7543     }
7544   else if (TREE_CODE (label) == LABEL_DECL)
7545     ;
7546   else switch (TREE_INT_CST_LOW (label))
7547     {
7548     case 0:
7549       if (is_break)
7550         error ("break statement not within loop or switch");
7551       else
7552         error ("continue statement not within a loop");
7553       return NULL_TREE;
7554
7555     case 1:
7556       gcc_assert (is_break);
7557       error ("break statement used with OpenMP for loop");
7558       return NULL_TREE;
7559
7560     default:
7561       gcc_unreachable ();
7562     }
7563
7564   if (skip)
7565     return NULL_TREE;
7566
7567   if (!is_break)
7568     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7569
7570   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7571 }
7572
7573 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7574
7575 static void
7576 emit_side_effect_warnings (tree expr)
7577 {
7578   if (expr == error_mark_node)
7579     ;
7580   else if (!TREE_SIDE_EFFECTS (expr))
7581     {
7582       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7583         warning (OPT_Wunused_value, "%Hstatement with no effect",
7584                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7585     }
7586   else
7587     warn_if_unused_value (expr, input_location);
7588 }
7589
7590 /* Process an expression as if it were a complete statement.  Emit
7591    diagnostics, but do not call ADD_STMT.  */
7592
7593 tree
7594 c_process_expr_stmt (tree expr)
7595 {
7596   if (!expr)
7597     return NULL_TREE;
7598
7599   if (warn_sequence_point)
7600     verify_sequence_points (expr);
7601
7602   if (TREE_TYPE (expr) != error_mark_node
7603       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7604       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7605     error ("expression statement has incomplete type");
7606
7607   /* If we're not processing a statement expression, warn about unused values.
7608      Warnings for statement expressions will be emitted later, once we figure
7609      out which is the result.  */
7610   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7611       && warn_unused_value)
7612     emit_side_effect_warnings (expr);
7613
7614   /* If the expression is not of a type to which we cannot assign a line
7615      number, wrap the thing in a no-op NOP_EXPR.  */
7616   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7617     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7618
7619   if (CAN_HAVE_LOCATION_P (expr))
7620     SET_EXPR_LOCATION (expr, input_location);
7621
7622   return expr;
7623 }
7624
7625 /* Emit an expression as a statement.  */
7626
7627 tree
7628 c_finish_expr_stmt (tree expr)
7629 {
7630   if (expr)
7631     return add_stmt (c_process_expr_stmt (expr));
7632   else
7633     return NULL;
7634 }
7635
7636 /* Do the opposite and emit a statement as an expression.  To begin,
7637    create a new binding level and return it.  */
7638
7639 tree
7640 c_begin_stmt_expr (void)
7641 {
7642   tree ret;
7643   struct c_label_context_se *nstack;
7644   struct c_label_list *glist;
7645
7646   /* We must force a BLOCK for this level so that, if it is not expanded
7647      later, there is a way to turn off the entire subtree of blocks that
7648      are contained in it.  */
7649   keep_next_level ();
7650   ret = c_begin_compound_stmt (true);
7651   if (c_switch_stack)
7652     {
7653       c_switch_stack->blocked_stmt_expr++;
7654       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7655     }
7656   for (glist = label_context_stack_se->labels_used;
7657        glist != NULL;
7658        glist = glist->next)
7659     {
7660       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7661     }
7662   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7663   nstack->labels_def = NULL;
7664   nstack->labels_used = NULL;
7665   nstack->next = label_context_stack_se;
7666   label_context_stack_se = nstack;
7667
7668   /* Mark the current statement list as belonging to a statement list.  */
7669   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7670
7671   return ret;
7672 }
7673
7674 tree
7675 c_finish_stmt_expr (tree body)
7676 {
7677   tree last, type, tmp, val;
7678   tree *last_p;
7679   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7680
7681   body = c_end_compound_stmt (body, true);
7682   if (c_switch_stack)
7683     {
7684       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7685       c_switch_stack->blocked_stmt_expr--;
7686     }
7687   /* It is no longer possible to jump to labels defined within this
7688      statement expression.  */
7689   for (dlist = label_context_stack_se->labels_def;
7690        dlist != NULL;
7691        dlist = dlist->next)
7692     {
7693       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7694     }
7695   /* It is again possible to define labels with a goto just outside
7696      this statement expression.  */
7697   for (glist = label_context_stack_se->next->labels_used;
7698        glist != NULL;
7699        glist = glist->next)
7700     {
7701       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7702       glist_prev = glist;
7703     }
7704   if (glist_prev != NULL)
7705     glist_prev->next = label_context_stack_se->labels_used;
7706   else
7707     label_context_stack_se->next->labels_used
7708       = label_context_stack_se->labels_used;
7709   label_context_stack_se = label_context_stack_se->next;
7710
7711   /* Locate the last statement in BODY.  See c_end_compound_stmt
7712      about always returning a BIND_EXPR.  */
7713   last_p = &BIND_EXPR_BODY (body);
7714   last = BIND_EXPR_BODY (body);
7715
7716  continue_searching:
7717   if (TREE_CODE (last) == STATEMENT_LIST)
7718     {
7719       tree_stmt_iterator i;
7720
7721       /* This can happen with degenerate cases like ({ }).  No value.  */
7722       if (!TREE_SIDE_EFFECTS (last))
7723         return body;
7724
7725       /* If we're supposed to generate side effects warnings, process
7726          all of the statements except the last.  */
7727       if (warn_unused_value)
7728         {
7729           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7730             emit_side_effect_warnings (tsi_stmt (i));
7731         }
7732       else
7733         i = tsi_last (last);
7734       last_p = tsi_stmt_ptr (i);
7735       last = *last_p;
7736     }
7737
7738   /* If the end of the list is exception related, then the list was split
7739      by a call to push_cleanup.  Continue searching.  */
7740   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7741       || TREE_CODE (last) == TRY_CATCH_EXPR)
7742     {
7743       last_p = &TREE_OPERAND (last, 0);
7744       last = *last_p;
7745       goto continue_searching;
7746     }
7747
7748   /* In the case that the BIND_EXPR is not necessary, return the
7749      expression out from inside it.  */
7750   if (last == error_mark_node
7751       || (last == BIND_EXPR_BODY (body)
7752           && BIND_EXPR_VARS (body) == NULL))
7753     {
7754       /* Do not warn if the return value of a statement expression is
7755          unused.  */
7756       if (CAN_HAVE_LOCATION_P (last))
7757         TREE_NO_WARNING (last) = 1;
7758       return last;
7759     }
7760
7761   /* Extract the type of said expression.  */
7762   type = TREE_TYPE (last);
7763
7764   /* If we're not returning a value at all, then the BIND_EXPR that
7765      we already have is a fine expression to return.  */
7766   if (!type || VOID_TYPE_P (type))
7767     return body;
7768
7769   /* Now that we've located the expression containing the value, it seems
7770      silly to make voidify_wrapper_expr repeat the process.  Create a
7771      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7772   tmp = create_tmp_var_raw (type, NULL);
7773
7774   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7775      tree_expr_nonnegative_p giving up immediately.  */
7776   val = last;
7777   if (TREE_CODE (val) == NOP_EXPR
7778       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7779     val = TREE_OPERAND (val, 0);
7780
7781   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7782   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7783
7784   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7785 }
7786
7787 /* Begin the scope of an identifier of variably modified type, scope
7788    number SCOPE.  Jumping from outside this scope to inside it is not
7789    permitted.  */
7790
7791 void
7792 c_begin_vm_scope (unsigned int scope)
7793 {
7794   struct c_label_context_vm *nstack;
7795   struct c_label_list *glist;
7796
7797   gcc_assert (scope > 0);
7798
7799   /* At file_scope, we don't have to do any processing.  */
7800   if (label_context_stack_vm == NULL)
7801     return;
7802
7803   if (c_switch_stack && !c_switch_stack->blocked_vm)
7804     c_switch_stack->blocked_vm = scope;
7805   for (glist = label_context_stack_vm->labels_used;
7806        glist != NULL;
7807        glist = glist->next)
7808     {
7809       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7810     }
7811   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7812   nstack->labels_def = NULL;
7813   nstack->labels_used = NULL;
7814   nstack->scope = scope;
7815   nstack->next = label_context_stack_vm;
7816   label_context_stack_vm = nstack;
7817 }
7818
7819 /* End a scope which may contain identifiers of variably modified
7820    type, scope number SCOPE.  */
7821
7822 void
7823 c_end_vm_scope (unsigned int scope)
7824 {
7825   if (label_context_stack_vm == NULL)
7826     return;
7827   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7828     c_switch_stack->blocked_vm = 0;
7829   /* We may have a number of nested scopes of identifiers with
7830      variably modified type, all at this depth.  Pop each in turn.  */
7831   while (label_context_stack_vm->scope == scope)
7832     {
7833       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7834
7835       /* It is no longer possible to jump to labels defined within this
7836          scope.  */
7837       for (dlist = label_context_stack_vm->labels_def;
7838            dlist != NULL;
7839            dlist = dlist->next)
7840         {
7841           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7842         }
7843       /* It is again possible to define labels with a goto just outside
7844          this scope.  */
7845       for (glist = label_context_stack_vm->next->labels_used;
7846            glist != NULL;
7847            glist = glist->next)
7848         {
7849           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7850           glist_prev = glist;
7851         }
7852       if (glist_prev != NULL)
7853         glist_prev->next = label_context_stack_vm->labels_used;
7854       else
7855         label_context_stack_vm->next->labels_used
7856           = label_context_stack_vm->labels_used;
7857       label_context_stack_vm = label_context_stack_vm->next;
7858     }
7859 }
7860 \f
7861 /* Begin and end compound statements.  This is as simple as pushing
7862    and popping new statement lists from the tree.  */
7863
7864 tree
7865 c_begin_compound_stmt (bool do_scope)
7866 {
7867   tree stmt = push_stmt_list ();
7868   if (do_scope)
7869     push_scope ();
7870   return stmt;
7871 }
7872
7873 tree
7874 c_end_compound_stmt (tree stmt, bool do_scope)
7875 {
7876   tree block = NULL;
7877
7878   if (do_scope)
7879     {
7880       if (c_dialect_objc ())
7881         objc_clear_super_receiver ();
7882       block = pop_scope ();
7883     }
7884
7885   stmt = pop_stmt_list (stmt);
7886   stmt = c_build_bind_expr (block, stmt);
7887
7888   /* If this compound statement is nested immediately inside a statement
7889      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7890      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7891      STATEMENT_LISTs merge, and thus we can lose track of what statement
7892      was really last.  */
7893   if (cur_stmt_list
7894       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7895       && TREE_CODE (stmt) != BIND_EXPR)
7896     {
7897       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7898       TREE_SIDE_EFFECTS (stmt) = 1;
7899     }
7900
7901   return stmt;
7902 }
7903
7904 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7905    when the current scope is exited.  EH_ONLY is true when this is not
7906    meant to apply to normal control flow transfer.  */
7907
7908 void
7909 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7910 {
7911   enum tree_code code;
7912   tree stmt, list;
7913   bool stmt_expr;
7914
7915   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7916   stmt = build_stmt (code, NULL, cleanup);
7917   add_stmt (stmt);
7918   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7919   list = push_stmt_list ();
7920   TREE_OPERAND (stmt, 0) = list;
7921   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7922 }
7923 \f
7924 /* Build a binary-operation expression without default conversions.
7925    CODE is the kind of expression to build.
7926    LOCATION is the operator's location.
7927    This function differs from `build' in several ways:
7928    the data type of the result is computed and recorded in it,
7929    warnings are generated if arg data types are invalid,
7930    special handling for addition and subtraction of pointers is known,
7931    and some optimization is done (operations on narrow ints
7932    are done in the narrower type when that gives the same result).
7933    Constant folding is also done before the result is returned.
7934
7935    Note that the operands will never have enumeral types, or function
7936    or array types, because either they will have the default conversions
7937    performed or they have both just been converted to some other type in which
7938    the arithmetic is to be done.  */
7939
7940 tree
7941 build_binary_op (location_t location, enum tree_code code,
7942                  tree orig_op0, tree orig_op1, int convert_p)
7943 {
7944   tree type0, type1;
7945   enum tree_code code0, code1;
7946   tree op0, op1;
7947   const char *invalid_op_diag;
7948
7949   /* Expression code to give to the expression when it is built.
7950      Normally this is CODE, which is what the caller asked for,
7951      but in some special cases we change it.  */
7952   enum tree_code resultcode = code;
7953
7954   /* Data type in which the computation is to be performed.
7955      In the simplest cases this is the common type of the arguments.  */
7956   tree result_type = NULL;
7957
7958   /* Nonzero means operands have already been type-converted
7959      in whatever way is necessary.
7960      Zero means they need to be converted to RESULT_TYPE.  */
7961   int converted = 0;
7962
7963   /* Nonzero means create the expression with this type, rather than
7964      RESULT_TYPE.  */
7965   tree build_type = 0;
7966
7967   /* Nonzero means after finally constructing the expression
7968      convert it to this type.  */
7969   tree final_type = 0;
7970
7971   /* Nonzero if this is an operation like MIN or MAX which can
7972      safely be computed in short if both args are promoted shorts.
7973      Also implies COMMON.
7974      -1 indicates a bitwise operation; this makes a difference
7975      in the exact conditions for when it is safe to do the operation
7976      in a narrower mode.  */
7977   int shorten = 0;
7978
7979   /* Nonzero if this is a comparison operation;
7980      if both args are promoted shorts, compare the original shorts.
7981      Also implies COMMON.  */
7982   int short_compare = 0;
7983
7984   /* Nonzero if this is a right-shift operation, which can be computed on the
7985      original short and then promoted if the operand is a promoted short.  */
7986   int short_shift = 0;
7987
7988   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7989   int common = 0;
7990
7991   /* True means types are compatible as far as ObjC is concerned.  */
7992   bool objc_ok;
7993
7994   if (location == UNKNOWN_LOCATION)
7995     location = input_location;
7996
7997   if (convert_p)
7998     {
7999       op0 = default_conversion (orig_op0);
8000       op1 = default_conversion (orig_op1);
8001     }
8002   else
8003     {
8004       op0 = orig_op0;
8005       op1 = orig_op1;
8006     }
8007
8008   type0 = TREE_TYPE (op0);
8009   type1 = TREE_TYPE (op1);
8010
8011   /* The expression codes of the data types of the arguments tell us
8012      whether the arguments are integers, floating, pointers, etc.  */
8013   code0 = TREE_CODE (type0);
8014   code1 = TREE_CODE (type1);
8015
8016   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8017   STRIP_TYPE_NOPS (op0);
8018   STRIP_TYPE_NOPS (op1);
8019
8020   /* If an error was already reported for one of the arguments,
8021      avoid reporting another error.  */
8022
8023   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8024     return error_mark_node;
8025
8026   if ((invalid_op_diag
8027        = targetm.invalid_binary_op (code, type0, type1)))
8028     {
8029       error_at (location, invalid_op_diag);
8030       return error_mark_node;
8031     }
8032
8033   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8034
8035   switch (code)
8036     {
8037     case PLUS_EXPR:
8038       /* Handle the pointer + int case.  */
8039       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8040         return pointer_int_sum (PLUS_EXPR, op0, op1);
8041       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8042         return pointer_int_sum (PLUS_EXPR, op1, op0);
8043       else
8044         common = 1;
8045       break;
8046
8047     case MINUS_EXPR:
8048       /* Subtraction of two similar pointers.
8049          We must subtract them as integers, then divide by object size.  */
8050       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8051           && comp_target_types (type0, type1))
8052         return pointer_diff (op0, op1);
8053       /* Handle pointer minus int.  Just like pointer plus int.  */
8054       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8055         return pointer_int_sum (MINUS_EXPR, op0, op1);
8056       else
8057         common = 1;
8058       break;
8059
8060     case MULT_EXPR:
8061       common = 1;
8062       break;
8063
8064     case TRUNC_DIV_EXPR:
8065     case CEIL_DIV_EXPR:
8066     case FLOOR_DIV_EXPR:
8067     case ROUND_DIV_EXPR:
8068     case EXACT_DIV_EXPR:
8069       warn_for_div_by_zero (op1);
8070
8071       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8072            || code0 == FIXED_POINT_TYPE
8073            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8074           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8075               || code1 == FIXED_POINT_TYPE
8076               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8077         {
8078           enum tree_code tcode0 = code0, tcode1 = code1;
8079
8080           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8081             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8082           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8083             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8084
8085           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8086               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8087             resultcode = RDIV_EXPR;
8088           else
8089             /* Although it would be tempting to shorten always here, that
8090                loses on some targets, since the modulo instruction is
8091                undefined if the quotient can't be represented in the
8092                computation mode.  We shorten only if unsigned or if
8093                dividing by something we know != -1.  */
8094             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8095                        || (TREE_CODE (op1) == INTEGER_CST
8096                            && !integer_all_onesp (op1)));
8097           common = 1;
8098         }
8099       break;
8100
8101     case BIT_AND_EXPR:
8102     case BIT_IOR_EXPR:
8103     case BIT_XOR_EXPR:
8104       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8105         shorten = -1;
8106       /* Allow vector types which are not floating point types.   */
8107       else if (code0 == VECTOR_TYPE
8108                && code1 == VECTOR_TYPE
8109                && !VECTOR_FLOAT_TYPE_P (type0)
8110                && !VECTOR_FLOAT_TYPE_P (type1))
8111         common = 1;
8112       break;
8113
8114     case TRUNC_MOD_EXPR:
8115     case FLOOR_MOD_EXPR:
8116       warn_for_div_by_zero (op1);
8117
8118       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8119         {
8120           /* Although it would be tempting to shorten always here, that loses
8121              on some targets, since the modulo instruction is undefined if the
8122              quotient can't be represented in the computation mode.  We shorten
8123              only if unsigned or if dividing by something we know != -1.  */
8124           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8125                      || (TREE_CODE (op1) == INTEGER_CST
8126                          && !integer_all_onesp (op1)));
8127           common = 1;
8128         }
8129       break;
8130
8131     case TRUTH_ANDIF_EXPR:
8132     case TRUTH_ORIF_EXPR:
8133     case TRUTH_AND_EXPR:
8134     case TRUTH_OR_EXPR:
8135     case TRUTH_XOR_EXPR:
8136       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8137            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8138            || code0 == FIXED_POINT_TYPE)
8139           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8140               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8141               || code1 == FIXED_POINT_TYPE))
8142         {
8143           /* Result of these operations is always an int,
8144              but that does not mean the operands should be
8145              converted to ints!  */
8146           result_type = integer_type_node;
8147           op0 = c_common_truthvalue_conversion (location, op0);
8148           op1 = c_common_truthvalue_conversion (location, op1);
8149           converted = 1;
8150         }
8151       break;
8152
8153       /* Shift operations: result has same type as first operand;
8154          always convert second operand to int.
8155          Also set SHORT_SHIFT if shifting rightward.  */
8156
8157     case RSHIFT_EXPR:
8158       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8159           && code1 == INTEGER_TYPE)
8160         {
8161           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8162             {
8163               if (tree_int_cst_sgn (op1) < 0)
8164                 warning (0, "right shift count is negative");
8165               else
8166                 {
8167                   if (!integer_zerop (op1))
8168                     short_shift = 1;
8169
8170                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8171                     warning (0, "right shift count >= width of type");
8172                 }
8173             }
8174
8175           /* Use the type of the value to be shifted.  */
8176           result_type = type0;
8177           /* Convert the shift-count to an integer, regardless of size
8178              of value being shifted.  */
8179           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8180             op1 = convert (integer_type_node, op1);
8181           /* Avoid converting op1 to result_type later.  */
8182           converted = 1;
8183         }
8184       break;
8185
8186     case LSHIFT_EXPR:
8187       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8188           && code1 == INTEGER_TYPE)
8189         {
8190           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8191             {
8192               if (tree_int_cst_sgn (op1) < 0)
8193                 warning (0, "left shift count is negative");
8194
8195               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8196                 warning (0, "left shift count >= width of type");
8197             }
8198
8199           /* Use the type of the value to be shifted.  */
8200           result_type = type0;
8201           /* Convert the shift-count to an integer, regardless of size
8202              of value being shifted.  */
8203           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8204             op1 = convert (integer_type_node, op1);
8205           /* Avoid converting op1 to result_type later.  */
8206           converted = 1;
8207         }
8208       break;
8209
8210     case EQ_EXPR:
8211     case NE_EXPR:
8212       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8213         warning_at (location,
8214                     OPT_Wfloat_equal,
8215                     "comparing floating point with == or != is unsafe");
8216       /* Result of comparison is always int,
8217          but don't convert the args to int!  */
8218       build_type = integer_type_node;
8219       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8220            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8221           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8222               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8223         short_compare = 1;
8224       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8225         {
8226           tree tt0 = TREE_TYPE (type0);
8227           tree tt1 = TREE_TYPE (type1);
8228           /* Anything compares with void *.  void * compares with anything.
8229              Otherwise, the targets must be compatible
8230              and both must be object or both incomplete.  */
8231           if (comp_target_types (type0, type1))
8232             result_type = common_pointer_type (type0, type1);
8233           else if (VOID_TYPE_P (tt0))
8234             {
8235               /* op0 != orig_op0 detects the case of something
8236                  whose value is 0 but which isn't a valid null ptr const.  */
8237               if (pedantic && !null_pointer_constant_p (orig_op0)
8238                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8239                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8240                          "comparison of %<void *%> with function pointer");
8241             }
8242           else if (VOID_TYPE_P (tt1))
8243             {
8244               if (pedantic && !null_pointer_constant_p (orig_op1)
8245                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8246                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8247                          "comparison of %<void *%> with function pointer");
8248             }
8249           else
8250             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8251             if (!objc_ok)
8252               pedwarn (location, 0,
8253                        "comparison of distinct pointer types lacks a cast");
8254
8255           if (result_type == NULL_TREE)
8256             result_type = ptr_type_node;
8257         }
8258       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8259         {
8260           if (TREE_CODE (op0) == ADDR_EXPR
8261               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8262             warning_at (location,
8263                         OPT_Waddress, "the address of %qD will never be NULL",
8264                         TREE_OPERAND (op0, 0));
8265           result_type = type0;
8266         }
8267       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8268         {
8269           if (TREE_CODE (op1) == ADDR_EXPR
8270               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8271             warning_at (location,
8272                         OPT_Waddress, "the address of %qD will never be NULL",
8273                         TREE_OPERAND (op1, 0));
8274           result_type = type1;
8275         }
8276       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8277         {
8278           result_type = type0;
8279           pedwarn (location, 0, "comparison between pointer and integer");
8280         }
8281       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8282         {
8283           result_type = type1;
8284           pedwarn (location, 0, "comparison between pointer and integer");
8285         }
8286       break;
8287
8288     case LE_EXPR:
8289     case GE_EXPR:
8290     case LT_EXPR:
8291     case GT_EXPR:
8292       build_type = integer_type_node;
8293       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8294            || code0 == FIXED_POINT_TYPE)
8295           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8296               || code1 == FIXED_POINT_TYPE))
8297         short_compare = 1;
8298       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8299         {
8300           if (comp_target_types (type0, type1))
8301             {
8302               result_type = common_pointer_type (type0, type1);
8303               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8304                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8305                 pedwarn (location, 0,
8306                          "comparison of complete and incomplete pointers");
8307               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8308                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8309                          "ordered comparisons of pointers to functions");
8310             }
8311           else
8312             {
8313               result_type = ptr_type_node;
8314               pedwarn (location, 0,
8315                        "comparison of distinct pointer types lacks a cast");
8316             }
8317         }
8318       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8319         {
8320           result_type = type0;
8321           if (pedantic)
8322             pedwarn (location, OPT_pedantic,
8323                      "ordered comparison of pointer with integer zero");
8324           else if (extra_warnings)
8325             warning_at (location, OPT_Wextra,
8326                      "ordered comparison of pointer with integer zero");
8327         }
8328       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8329         {
8330           result_type = type1;
8331           pedwarn (location, OPT_pedantic,
8332                    "ordered comparison of pointer with integer zero");
8333         }
8334       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8335         {
8336           result_type = type0;
8337           pedwarn (location, 0, "comparison between pointer and integer");
8338         }
8339       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8340         {
8341           result_type = type1;
8342           pedwarn (location, 0, "comparison between pointer and integer");
8343         }
8344       break;
8345
8346     default:
8347       gcc_unreachable ();
8348     }
8349
8350   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8351     return error_mark_node;
8352
8353   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8354       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8355           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8356                                                     TREE_TYPE (type1))))
8357     {
8358       binary_op_error (location, code, type0, type1);
8359       return error_mark_node;
8360     }
8361
8362   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8363        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8364       &&
8365       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8366        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8367     {
8368       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8369
8370       if (shorten || common || short_compare)
8371         {
8372           result_type = c_common_type (type0, type1);
8373           if (result_type == error_mark_node)
8374             return error_mark_node;
8375         }
8376
8377       /* For certain operations (which identify themselves by shorten != 0)
8378          if both args were extended from the same smaller type,
8379          do the arithmetic in that type and then extend.
8380
8381          shorten !=0 and !=1 indicates a bitwise operation.
8382          For them, this optimization is safe only if
8383          both args are zero-extended or both are sign-extended.
8384          Otherwise, we might change the result.
8385          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8386          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8387
8388       if (shorten && none_complex)
8389         {
8390           final_type = result_type;
8391           result_type = shorten_binary_op (result_type, op0, op1,
8392                                            shorten == -1);
8393         }
8394
8395       /* Shifts can be shortened if shifting right.  */
8396
8397       if (short_shift)
8398         {
8399           int unsigned_arg;
8400           tree arg0 = get_narrower (op0, &unsigned_arg);
8401
8402           final_type = result_type;
8403
8404           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8405             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8406
8407           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8408               /* We can shorten only if the shift count is less than the
8409                  number of bits in the smaller type size.  */
8410               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8411               /* We cannot drop an unsigned shift after sign-extension.  */
8412               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8413             {
8414               /* Do an unsigned shift if the operand was zero-extended.  */
8415               result_type
8416                 = c_common_signed_or_unsigned_type (unsigned_arg,
8417                                                     TREE_TYPE (arg0));
8418               /* Convert value-to-be-shifted to that type.  */
8419               if (TREE_TYPE (op0) != result_type)
8420                 op0 = convert (result_type, op0);
8421               converted = 1;
8422             }
8423         }
8424
8425       /* Comparison operations are shortened too but differently.
8426          They identify themselves by setting short_compare = 1.  */
8427
8428       if (short_compare)
8429         {
8430           /* Don't write &op0, etc., because that would prevent op0
8431              from being kept in a register.
8432              Instead, make copies of the our local variables and
8433              pass the copies by reference, then copy them back afterward.  */
8434           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8435           enum tree_code xresultcode = resultcode;
8436           tree val
8437             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8438
8439           if (val != 0)
8440             return val;
8441
8442           op0 = xop0, op1 = xop1;
8443           converted = 1;
8444           resultcode = xresultcode;
8445
8446           if (warn_sign_compare && !skip_evaluation)
8447             {
8448               warn_for_sign_compare (location, orig_op0, orig_op1, op0, op1,
8449                                      result_type, resultcode);
8450             }
8451         }
8452     }
8453
8454   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8455      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8456      Then the expression will be built.
8457      It will be given type FINAL_TYPE if that is nonzero;
8458      otherwise, it will be given type RESULT_TYPE.  */
8459
8460   if (!result_type)
8461     {
8462       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
8463       return error_mark_node;
8464     }
8465
8466   if (!converted)
8467     {
8468       if (TREE_TYPE (op0) != result_type)
8469         op0 = convert_and_check (result_type, op0);
8470       if (TREE_TYPE (op1) != result_type)
8471         op1 = convert_and_check (result_type, op1);
8472
8473       /* This can happen if one operand has a vector type, and the other
8474          has a different type.  */
8475       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8476         return error_mark_node;
8477     }
8478
8479   if (build_type == NULL_TREE)
8480     build_type = result_type;
8481
8482   {
8483     /* Treat expressions in initializers specially as they can't trap.  */
8484     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8485                                                                     build_type,
8486                                                                     op0, op1)
8487                                          : fold_build2 (resultcode, build_type,
8488                                                         op0, op1);
8489
8490     if (final_type != 0)
8491       result = convert (final_type, result);
8492     return result;
8493   }
8494 }
8495
8496
8497 /* Convert EXPR to be a truth-value, validating its type for this
8498    purpose.  LOCATION is the source location for the expression.  */
8499
8500 tree
8501 c_objc_common_truthvalue_conversion (location_t location, tree expr)
8502 {
8503   switch (TREE_CODE (TREE_TYPE (expr)))
8504     {
8505     case ARRAY_TYPE:
8506       error_at (location, "used array that cannot be converted to pointer where scalar is required");
8507       return error_mark_node;
8508
8509     case RECORD_TYPE:
8510       error_at (location, "used struct type value where scalar is required");
8511       return error_mark_node;
8512
8513     case UNION_TYPE:
8514       error_at (location, "used union type value where scalar is required");
8515       return error_mark_node;
8516
8517     case FUNCTION_TYPE:
8518       gcc_unreachable ();
8519
8520     default:
8521       break;
8522     }
8523
8524   /* ??? Should we also give an error for void and vectors rather than
8525      leaving those to give errors later?  */
8526   return c_common_truthvalue_conversion (location, expr);
8527 }
8528 \f
8529
8530 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8531    required.  */
8532
8533 tree
8534 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8535 {
8536   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8537     {
8538       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8539       /* Executing a compound literal inside a function reinitializes
8540          it.  */
8541       if (!TREE_STATIC (decl))
8542         *se = true;
8543       return decl;
8544     }
8545   else
8546     return expr;
8547 }
8548 \f
8549 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8550
8551 tree
8552 c_begin_omp_parallel (void)
8553 {
8554   tree block;
8555
8556   keep_next_level ();
8557   block = c_begin_compound_stmt (true);
8558
8559   return block;
8560 }
8561
8562 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8563
8564 tree
8565 c_finish_omp_parallel (tree clauses, tree block)
8566 {
8567   tree stmt;
8568
8569   block = c_end_compound_stmt (block, true);
8570
8571   stmt = make_node (OMP_PARALLEL);
8572   TREE_TYPE (stmt) = void_type_node;
8573   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8574   OMP_PARALLEL_BODY (stmt) = block;
8575
8576   return add_stmt (stmt);
8577 }
8578
8579 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8580
8581 tree
8582 c_begin_omp_task (void)
8583 {
8584   tree block;
8585
8586   keep_next_level ();
8587   block = c_begin_compound_stmt (true);
8588
8589   return block;
8590 }
8591
8592 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8593
8594 tree
8595 c_finish_omp_task (tree clauses, tree block)
8596 {
8597   tree stmt;
8598
8599   block = c_end_compound_stmt (block, true);
8600
8601   stmt = make_node (OMP_TASK);
8602   TREE_TYPE (stmt) = void_type_node;
8603   OMP_TASK_CLAUSES (stmt) = clauses;
8604   OMP_TASK_BODY (stmt) = block;
8605
8606   return add_stmt (stmt);
8607 }
8608
8609 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8610    Remove any elements from the list that are invalid.  */
8611
8612 tree
8613 c_finish_omp_clauses (tree clauses)
8614 {
8615   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8616   tree c, t, *pc = &clauses;
8617   const char *name;
8618
8619   bitmap_obstack_initialize (NULL);
8620   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8621   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8622   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8623
8624   for (pc = &clauses, c = clauses; c ; c = *pc)
8625     {
8626       bool remove = false;
8627       bool need_complete = false;
8628       bool need_implicitly_determined = false;
8629
8630       switch (OMP_CLAUSE_CODE (c))
8631         {
8632         case OMP_CLAUSE_SHARED:
8633           name = "shared";
8634           need_implicitly_determined = true;
8635           goto check_dup_generic;
8636
8637         case OMP_CLAUSE_PRIVATE:
8638           name = "private";
8639           need_complete = true;
8640           need_implicitly_determined = true;
8641           goto check_dup_generic;
8642
8643         case OMP_CLAUSE_REDUCTION:
8644           name = "reduction";
8645           need_implicitly_determined = true;
8646           t = OMP_CLAUSE_DECL (c);
8647           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8648               || POINTER_TYPE_P (TREE_TYPE (t)))
8649             {
8650               error ("%qE has invalid type for %<reduction%>", t);
8651               remove = true;
8652             }
8653           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8654             {
8655               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8656               const char *r_name = NULL;
8657
8658               switch (r_code)
8659                 {
8660                 case PLUS_EXPR:
8661                 case MULT_EXPR:
8662                 case MINUS_EXPR:
8663                   break;
8664                 case BIT_AND_EXPR:
8665                   r_name = "&";
8666                   break;
8667                 case BIT_XOR_EXPR:
8668                   r_name = "^";
8669                   break;
8670                 case BIT_IOR_EXPR:
8671                   r_name = "|";
8672                   break;
8673                 case TRUTH_ANDIF_EXPR:
8674                   r_name = "&&";
8675                   break;
8676                 case TRUTH_ORIF_EXPR:
8677                   r_name = "||";
8678                   break;
8679                 default:
8680                   gcc_unreachable ();
8681                 }
8682               if (r_name)
8683                 {
8684                   error ("%qE has invalid type for %<reduction(%s)%>",
8685                          t, r_name);
8686                   remove = true;
8687                 }
8688             }
8689           goto check_dup_generic;
8690
8691         case OMP_CLAUSE_COPYPRIVATE:
8692           name = "copyprivate";
8693           goto check_dup_generic;
8694
8695         case OMP_CLAUSE_COPYIN:
8696           name = "copyin";
8697           t = OMP_CLAUSE_DECL (c);
8698           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8699             {
8700               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8701               remove = true;
8702             }
8703           goto check_dup_generic;
8704
8705         check_dup_generic:
8706           t = OMP_CLAUSE_DECL (c);
8707           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8708             {
8709               error ("%qE is not a variable in clause %qs", t, name);
8710               remove = true;
8711             }
8712           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8713                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8714                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8715             {
8716               error ("%qE appears more than once in data clauses", t);
8717               remove = true;
8718             }
8719           else
8720             bitmap_set_bit (&generic_head, DECL_UID (t));
8721           break;
8722
8723         case OMP_CLAUSE_FIRSTPRIVATE:
8724           name = "firstprivate";
8725           t = OMP_CLAUSE_DECL (c);
8726           need_complete = true;
8727           need_implicitly_determined = true;
8728           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8729             {
8730               error ("%qE is not a variable in clause %<firstprivate%>", t);
8731               remove = true;
8732             }
8733           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8734                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8735             {
8736               error ("%qE appears more than once in data clauses", t);
8737               remove = true;
8738             }
8739           else
8740             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8741           break;
8742
8743         case OMP_CLAUSE_LASTPRIVATE:
8744           name = "lastprivate";
8745           t = OMP_CLAUSE_DECL (c);
8746           need_complete = true;
8747           need_implicitly_determined = true;
8748           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8749             {
8750               error ("%qE is not a variable in clause %<lastprivate%>", t);
8751               remove = true;
8752             }
8753           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8754                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8755             {
8756               error ("%qE appears more than once in data clauses", t);
8757               remove = true;
8758             }
8759           else
8760             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8761           break;
8762
8763         case OMP_CLAUSE_IF:
8764         case OMP_CLAUSE_NUM_THREADS:
8765         case OMP_CLAUSE_SCHEDULE:
8766         case OMP_CLAUSE_NOWAIT:
8767         case OMP_CLAUSE_ORDERED:
8768         case OMP_CLAUSE_DEFAULT:
8769         case OMP_CLAUSE_UNTIED:
8770         case OMP_CLAUSE_COLLAPSE:
8771           pc = &OMP_CLAUSE_CHAIN (c);
8772           continue;
8773
8774         default:
8775           gcc_unreachable ();
8776         }
8777
8778       if (!remove)
8779         {
8780           t = OMP_CLAUSE_DECL (c);
8781
8782           if (need_complete)
8783             {
8784               t = require_complete_type (t);
8785               if (t == error_mark_node)
8786                 remove = true;
8787             }
8788
8789           if (need_implicitly_determined)
8790             {
8791               const char *share_name = NULL;
8792
8793               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8794                 share_name = "threadprivate";
8795               else switch (c_omp_predetermined_sharing (t))
8796                 {
8797                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8798                   break;
8799                 case OMP_CLAUSE_DEFAULT_SHARED:
8800                   share_name = "shared";
8801                   break;
8802                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8803                   share_name = "private";
8804                   break;
8805                 default:
8806                   gcc_unreachable ();
8807                 }
8808               if (share_name)
8809                 {
8810                   error ("%qE is predetermined %qs for %qs",
8811                          t, share_name, name);
8812                   remove = true;
8813                 }
8814             }
8815         }
8816
8817       if (remove)
8818         *pc = OMP_CLAUSE_CHAIN (c);
8819       else
8820         pc = &OMP_CLAUSE_CHAIN (c);
8821     }
8822
8823   bitmap_obstack_release (NULL);
8824   return clauses;
8825 }
8826
8827 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8828    down to the element type of an array.  */
8829
8830 tree
8831 c_build_qualified_type (tree type, int type_quals)
8832 {
8833   if (type == error_mark_node)
8834     return type;
8835
8836   if (TREE_CODE (type) == ARRAY_TYPE)
8837     {
8838       tree t;
8839       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8840                                                   type_quals);
8841
8842       /* See if we already have an identically qualified type.  */
8843       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8844         {
8845           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8846               && TYPE_NAME (t) == TYPE_NAME (type)
8847               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8848               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8849                                        TYPE_ATTRIBUTES (type)))
8850             break;
8851         }
8852       if (!t)
8853         {
8854           tree domain = TYPE_DOMAIN (type);
8855
8856           t = build_variant_type_copy (type);
8857           TREE_TYPE (t) = element_type;
8858
8859           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8860               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8861             SET_TYPE_STRUCTURAL_EQUALITY (t);
8862           else if (TYPE_CANONICAL (element_type) != element_type
8863                    || (domain && TYPE_CANONICAL (domain) != domain))
8864             {
8865               tree unqualified_canon
8866                 = build_array_type (TYPE_CANONICAL (element_type),
8867                                     domain? TYPE_CANONICAL (domain)
8868                                           : NULL_TREE);
8869               TYPE_CANONICAL (t)
8870                 = c_build_qualified_type (unqualified_canon, type_quals);
8871             }
8872           else
8873             TYPE_CANONICAL (t) = t;
8874         }
8875       return t;
8876     }
8877
8878   /* A restrict-qualified pointer type must be a pointer to object or
8879      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8880      REFERENCE_TYPEs, which is appropriate for C++.  */
8881   if ((type_quals & TYPE_QUAL_RESTRICT)
8882       && (!POINTER_TYPE_P (type)
8883           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8884     {
8885       error ("invalid use of %<restrict%>");
8886       type_quals &= ~TYPE_QUAL_RESTRICT;
8887     }
8888
8889   return build_qualified_type (type, type_quals);
8890 }