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 "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static 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 (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         bool t1_complete, t2_complete;
 331
 332         /* We should not have any type quals on arrays at all.  */
 333         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 334
 335         t1_complete = COMPLETE_TYPE_P (t1);
 336         t2_complete = COMPLETE_TYPE_P (t2);
 337
 338         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 339         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 340
 341         d1_variable = (!d1_zero
 342                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 343                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 344         d2_variable = (!d2_zero
 345                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 346                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 347         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 348         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 349
 350         /* Save space: see if the result is identical to one of the args.  */
 351         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 352             && (d2_variable || d2_zero || !d1_variable))
 353           return build_type_attribute_variant (t1, attributes);
 354         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 355             && (d1_variable || d1_zero || !d2_variable))
 356           return build_type_attribute_variant (t2, attributes);
 357
 358         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 359           return build_type_attribute_variant (t1, attributes);
 360         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 361           return build_type_attribute_variant (t2, attributes);
 362
 363         /* Merge the element types, and have a size if either arg has
 364            one.  We may have qualifiers on the element types.  To set
 365            up TYPE_MAIN_VARIANT correctly, we need to form the
 366            composite of the unqualified types and add the qualifiers
 367            back at the end.  */
 368         quals = TYPE_QUALS (strip_array_types (elt));
 369         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 370         t1 = build_array_type (unqual_elt,
 371                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 372                                              && (d2_variable
 373                                                  || d2_zero
 374                                                  || !d1_variable))
 375                                             ? t1
 376                                             : t2));
 377         /* Ensure a composite type involving a zero-length array type
 378            is a zero-length type not an incomplete type.  */
 379         if (d1_zero && d2_zero
 380             && (t1_complete || t2_complete)
 381             && !COMPLETE_TYPE_P (t1))
 382           {
 383             TYPE_SIZE (t1) = bitsize_zero_node;
 384             TYPE_SIZE_UNIT (t1) = size_zero_node;
 385           }
 386         t1 = c_build_qualified_type (t1, quals);
 387         return build_type_attribute_variant (t1, attributes);
 388       }
 389
 390     case ENUMERAL_TYPE:
 391     case RECORD_TYPE:
 392     case UNION_TYPE:
 393       if (attributes != NULL)
 394         {
 395           /* Try harder not to create a new aggregate type.  */
 396           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 397             return t1;
 398           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 399             return t2;
 400         }
 401       return build_type_attribute_variant (t1, attributes);
 402
 403     case FUNCTION_TYPE:
 404       /* Function types: prefer the one that specified arg types.
 405          If both do, merge the arg types.  Also merge the return types.  */
 406       {
 407         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 408         tree p1 = TYPE_ARG_TYPES (t1);
 409         tree p2 = TYPE_ARG_TYPES (t2);
 410         int len;
 411         tree newargs, n;
 412         int i;
 413
 414         /* Save space: see if the result is identical to one of the args.  */
 415         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 416           return build_type_attribute_variant (t1, attributes);
 417         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 418           return build_type_attribute_variant (t2, attributes);
 419
 420         /* Simple way if one arg fails to specify argument types.  */
 421         if (TYPE_ARG_TYPES (t1) == 0)
 422          {
 423             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 424             t1 = build_type_attribute_variant (t1, attributes);
 425             return qualify_type (t1, t2);
 426          }
 427         if (TYPE_ARG_TYPES (t2) == 0)
 428          {
 429            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 430            t1 = build_type_attribute_variant (t1, attributes);
 431            return qualify_type (t1, t2);
 432          }
 433
 434         /* If both args specify argument types, we must merge the two
 435            lists, argument by argument.  */
 436         /* Tell global_bindings_p to return false so that variable_size
 437            doesn't die on VLAs in parameter types.  */
 438         c_override_global_bindings_to_false = true;
 439
 440         len = list_length (p1);
 441         newargs = 0;
 442
 443         for (i = 0; i < len; i++)
 444           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 445
 446         n = newargs;
 447
 448         for (; p1;
 449              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 450           {
 451             /* A null type means arg type is not specified.
 452                Take whatever the other function type has.  */
 453             if (TREE_VALUE (p1) == 0)
 454               {
 455                 TREE_VALUE (n) = TREE_VALUE (p2);
 456                 goto parm_done;
 457               }
 458             if (TREE_VALUE (p2) == 0)
 459               {
 460                 TREE_VALUE (n) = TREE_VALUE (p1);
 461                 goto parm_done;
 462               }
 463
 464             /* Given  wait (union {union wait *u; int *i} *)
 465                and  wait (union wait *),
 466                prefer  union wait *  as type of parm.  */
 467             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 468                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 469               {
 470                 tree memb;
 471                 tree mv2 = TREE_VALUE (p2);
 472                 if (mv2 && mv2 != error_mark_node
 473                     && TREE_CODE (mv2) != ARRAY_TYPE)
 474                   mv2 = TYPE_MAIN_VARIANT (mv2);
 475                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 476                      memb; memb = TREE_CHAIN (memb))
 477                   {
 478                     tree mv3 = TREE_TYPE (memb);
 479                     if (mv3 && mv3 != error_mark_node
 480                         && TREE_CODE (mv3) != ARRAY_TYPE)
 481                       mv3 = TYPE_MAIN_VARIANT (mv3);
 482                     if (comptypes (mv3, mv2))
 483                       {
 484                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 485                                                          TREE_VALUE (p2));
 486                         if (pedantic)
 487                           pedwarn ("function types not truly compatible in ISO C");
 488                         goto parm_done;
 489                       }
 490                   }
 491               }
 492             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 493                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 494               {
 495                 tree memb;
 496                 tree mv1 = TREE_VALUE (p1);
 497                 if (mv1 && mv1 != error_mark_node
 498                     && TREE_CODE (mv1) != ARRAY_TYPE)
 499                   mv1 = TYPE_MAIN_VARIANT (mv1);
 500                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 501                      memb; memb = TREE_CHAIN (memb))
 502                   {
 503                     tree mv3 = TREE_TYPE (memb);
 504                     if (mv3 && mv3 != error_mark_node
 505                         && TREE_CODE (mv3) != ARRAY_TYPE)
 506                       mv3 = TYPE_MAIN_VARIANT (mv3);
 507                     if (comptypes (mv3, mv1))
 508                       {
 509                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 510                                                          TREE_VALUE (p1));
 511                         if (pedantic)
 512                           pedwarn ("function types not truly compatible in ISO C");
 513                         goto parm_done;
 514                       }
 515                   }
 516               }
 517             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 518           parm_done: ;
 519           }
 520
 521         c_override_global_bindings_to_false = false;
 522         t1 = build_function_type (valtype, newargs);
 523         t1 = qualify_type (t1, t2);
 524         /* ... falls through ...  */
 525       }
 526
 527     default:
 528       return build_type_attribute_variant (t1, attributes);
 529     }
 530
 531 }
 532
 533 /* Return the type of a conditional expression between pointers to
 534    possibly differently qualified versions of compatible types.
 535
 536    We assume that comp_target_types has already been done and returned
 537    nonzero; if that isn't so, this may crash.  */
 538
 539 static tree
 540 common_pointer_type (tree t1, tree t2)
 541 {
 542   tree attributes;
 543   tree pointed_to_1, mv1;
 544   tree pointed_to_2, mv2;
 545   tree target;
 546   unsigned target_quals;
 547
 548   /* Save time if the two types are the same.  */
 549
 550   if (t1 == t2) return t1;
 551
 552   /* If one type is nonsense, use the other.  */
 553   if (t1 == error_mark_node)
 554     return t2;
 555   if (t2 == error_mark_node)
 556     return t1;
 557
 558   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 559               && TREE_CODE (t2) == POINTER_TYPE);
 560
 561   /* Merge the attributes.  */
 562   attributes = targetm.merge_type_attributes (t1, t2);
 563
 564   /* Find the composite type of the target types, and combine the
 565      qualifiers of the two types' targets.  Do not lose qualifiers on
 566      array element types by taking the TYPE_MAIN_VARIANT.  */
 567   mv1 = pointed_to_1 = TREE_TYPE (t1);
 568   mv2 = pointed_to_2 = TREE_TYPE (t2);
 569   if (TREE_CODE (mv1) != ARRAY_TYPE)
 570     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 571   if (TREE_CODE (mv2) != ARRAY_TYPE)
 572     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 573   target = composite_type (mv1, mv2);
 574
 575   /* For function types do not merge const qualifiers, but drop them
 576      if used inconsistently.  The middle-end uses these to mark const
 577      and noreturn functions.  */
 578   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 579     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 580   else
 581     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 582   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 583   return build_type_attribute_variant (t1, attributes);
 584 }
 585
 586 /* Return the common type for two arithmetic types under the usual
 587    arithmetic conversions.  The default conversions have already been
 588    applied, and enumerated types converted to their compatible integer
 589    types.  The resulting type is unqualified and has no attributes.
 590
 591    This is the type for the result of most arithmetic operations
 592    if the operands have the given two types.  */
 593
 594 static tree
 595 c_common_type (tree t1, tree t2)
 596 {
 597   enum tree_code code1;
 598   enum tree_code code2;
 599
 600   /* If one type is nonsense, use the other.  */
 601   if (t1 == error_mark_node)
 602     return t2;
 603   if (t2 == error_mark_node)
 604     return t1;
 605
 606   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 607     t1 = TYPE_MAIN_VARIANT (t1);
 608
 609   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 610     t2 = TYPE_MAIN_VARIANT (t2);
 611
 612   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 613     t1 = build_type_attribute_variant (t1, NULL_TREE);
 614
 615   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 616     t2 = build_type_attribute_variant (t2, NULL_TREE);
 617
 618   /* Save time if the two types are the same.  */
 619
 620   if (t1 == t2) return t1;
 621
 622   code1 = TREE_CODE (t1);
 623   code2 = TREE_CODE (t2);
 624
 625   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 626               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 627               || code1 == INTEGER_TYPE);
 628   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 629               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 630               || code2 == INTEGER_TYPE);
 631
 632   /* When one operand is a decimal float type, the other operand cannot be
 633      a generic float type or a complex type.  We also disallow vector types
 634      here.  */
 635   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 636       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 637     {
 638       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 639         {
 640           error ("can%'t mix operands of decimal float and vector types");
 641           return error_mark_node;
 642         }
 643       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 644         {
 645           error ("can%'t mix operands of decimal float and complex types");
 646           return error_mark_node;
 647         }
 648       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 649         {
 650           error ("can%'t mix operands of decimal float and other float types");
 651           return error_mark_node;
 652         }
 653     }
 654
 655   /* If one type is a vector type, return that type.  (How the usual
 656      arithmetic conversions apply to the vector types extension is not
 657      precisely specified.)  */
 658   if (code1 == VECTOR_TYPE)
 659     return t1;
 660
 661   if (code2 == VECTOR_TYPE)
 662     return t2;
 663
 664   /* If one type is complex, form the common type of the non-complex
 665      components, then make that complex.  Use T1 or T2 if it is the
 666      required type.  */
 667   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 668     {
 669       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 670       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 671       tree subtype = c_common_type (subtype1, subtype2);
 672
 673       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 674         return t1;
 675       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 676         return t2;
 677       else
 678         return build_complex_type (subtype);
 679     }
 680
 681   /* If only one is real, use it as the result.  */
 682
 683   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 684     return t1;
 685
 686   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 687     return t2;
 688
 689   /* If both are real and either are decimal floating point types, use
 690      the decimal floating point type with the greater precision. */
 691
 692   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 693     {
 694       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 695           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 696         return dfloat128_type_node;
 697       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 698                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 699         return dfloat64_type_node;
 700       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 701                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 702         return dfloat32_type_node;
 703     }
 704
 705   /* Deal with fixed-point types.  */
 706   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 707     {
 708       unsigned int unsignedp = 0, satp = 0;
 709       enum machine_mode m1, m2;
 710       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 711
 712       m1 = TYPE_MODE (t1);
 713       m2 = TYPE_MODE (t2);
 714
 715       /* If one input type is saturating, the result type is saturating.  */
 716       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 717         satp = 1;
 718
 719       /* If both fixed-point types are unsigned, the result type is unsigned.
 720          When mixing fixed-point and integer types, follow the sign of the
 721          fixed-point type.
 722          Otherwise, the result type is signed.  */
 723       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 724            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 725           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 726               && TYPE_UNSIGNED (t1))
 727           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 728               && TYPE_UNSIGNED (t2)))
 729         unsignedp = 1;
 730
 731       /* The result type is signed.  */
 732       if (unsignedp == 0)
 733         {
 734           /* If the input type is unsigned, we need to convert to the
 735              signed type.  */
 736           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 737             {
 738               unsigned char mclass = 0;
 739               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 740                 mclass = MODE_FRACT;
 741               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 742                 mclass = MODE_ACCUM;
 743               else
 744                 gcc_unreachable ();
 745               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 746             }
 747           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 748             {
 749               unsigned char mclass = 0;
 750               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 751                 mclass = MODE_FRACT;
 752               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 753                 mclass = MODE_ACCUM;
 754               else
 755                 gcc_unreachable ();
 756               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 757             }
 758         }
 759
 760       if (code1 == FIXED_POINT_TYPE)
 761         {
 762           fbit1 = GET_MODE_FBIT (m1);
 763           ibit1 = GET_MODE_IBIT (m1);
 764         }
 765       else
 766         {
 767           fbit1 = 0;
 768           /* Signed integers need to subtract one sign bit.  */
 769           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 770         }
 771
 772       if (code2 == FIXED_POINT_TYPE)
 773         {
 774           fbit2 = GET_MODE_FBIT (m2);
 775           ibit2 = GET_MODE_IBIT (m2);
 776         }
 777       else
 778         {
 779           fbit2 = 0;
 780           /* Signed integers need to subtract one sign bit.  */
 781           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 782         }
 783
 784       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 785       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 786       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 787                                                  satp);
 788     }
 789
 790   /* Both real or both integers; use the one with greater precision.  */
 791
 792   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 793     return t1;
 794   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 795     return t2;
 796
 797   /* Same precision.  Prefer long longs to longs to ints when the
 798      same precision, following the C99 rules on integer type rank
 799      (which are equivalent to the C90 rules for C90 types).  */
 800
 801   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 802       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 803     return long_long_unsigned_type_node;
 804
 805   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 806       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 807     {
 808       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 809         return long_long_unsigned_type_node;
 810       else
 811         return long_long_integer_type_node;
 812     }
 813
 814   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 815       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 816     return long_unsigned_type_node;
 817
 818   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 819       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 820     {
 821       /* But preserve unsignedness from the other type,
 822          since long cannot hold all the values of an unsigned int.  */
 823       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 824         return long_unsigned_type_node;
 825       else
 826         return long_integer_type_node;
 827     }
 828
 829   /* Likewise, prefer long double to double even if same size.  */
 830   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 831       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 832     return long_double_type_node;
 833
 834   /* Otherwise prefer the unsigned one.  */
 835
 836   if (TYPE_UNSIGNED (t1))
 837     return t1;
 838   else
 839     return t2;
 840 }
 841 \f
 842 /* Wrapper around c_common_type that is used by c-common.c and other
 843    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 844    are allowed here and are converted to their compatible integer types.
 845    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 846    preferably a non-Boolean type as the common type.  */
 847 tree
 848 common_type (tree t1, tree t2)
 849 {
 850   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 851     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 852   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 853     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 854
 855   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 856   if (TREE_CODE (t1) == BOOLEAN_TYPE
 857       && TREE_CODE (t2) == BOOLEAN_TYPE)
 858     return boolean_type_node;
 859
 860   /* If either type is BOOLEAN_TYPE, then return the other.  */
 861   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 862     return t2;
 863   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 864     return t1;
 865
 866   return c_common_type (t1, t2);
 867 }
 868
 869 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 870    or various other operations.  Return 2 if they are compatible
 871    but a warning may be needed if you use them together.  */
 872
 873 int
 874 comptypes (tree type1, tree type2)
 875 {
 876   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 877   int val;
 878
 879   val = comptypes_internal (type1, type2);
 880   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 881
 882   return val;
 883 }
 884 \f
 885 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 886    or various other operations.  Return 2 if they are compatible
 887    but a warning may be needed if you use them together.  This
 888    differs from comptypes, in that we don't free the seen types.  */
 889
 890 static int
 891 comptypes_internal (const_tree type1, const_tree type2)
 892 {
 893   const_tree t1 = type1;
 894   const_tree t2 = type2;
 895   int attrval, val;
 896
 897   /* Suppress errors caused by previously reported errors.  */
 898
 899   if (t1 == t2 || !t1 || !t2
 900       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 901     return 1;
 902
 903   /* If either type is the internal version of sizetype, return the
 904      language version.  */
 905   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 906       && TYPE_ORIG_SIZE_TYPE (t1))
 907     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 908
 909   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 910       && TYPE_ORIG_SIZE_TYPE (t2))
 911     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 912
 913
 914   /* Enumerated types are compatible with integer types, but this is
 915      not transitive: two enumerated types in the same translation unit
 916      are compatible with each other only if they are the same type.  */
 917
 918   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 919     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 920   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 921     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 922
 923   if (t1 == t2)
 924     return 1;
 925
 926   /* Different classes of types can't be compatible.  */
 927
 928   if (TREE_CODE (t1) != TREE_CODE (t2))
 929     return 0;
 930
 931   /* Qualifiers must match. C99 6.7.3p9 */
 932
 933   if (TYPE_QUALS (CONST_CAST_TREE (t1)) != TYPE_QUALS (CONST_CAST_TREE (t2)))
 934     return 0;
 935
 936   /* Allow for two different type nodes which have essentially the same
 937      definition.  Note that we already checked for equality of the type
 938      qualifiers (just above).  */
 939
 940   if (TREE_CODE (t1) != ARRAY_TYPE
 941       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 942     return 1;
 943
 944   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 945   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 946      return 0;
 947
 948   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 949   val = 0;
 950
 951   switch (TREE_CODE (t1))
 952     {
 953     case POINTER_TYPE:
 954       /* Do not remove mode or aliasing information.  */
 955       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 956           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 957         break;
 958       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 959              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 960       break;
 961
 962     case FUNCTION_TYPE:
 963       val = function_types_compatible_p (t1, t2);
 964       break;
 965
 966     case ARRAY_TYPE:
 967       {
 968         tree d1 = TYPE_DOMAIN (t1);
 969         tree d2 = TYPE_DOMAIN (t2);
 970         bool d1_variable, d2_variable;
 971         bool d1_zero, d2_zero;
 972         val = 1;
 973
 974         /* Target types must match incl. qualifiers.  */
 975         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 976             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 977           return 0;
 978
 979         /* Sizes must match unless one is missing or variable.  */
 980         if (d1 == 0 || d2 == 0 || d1 == d2)
 981           break;
 982
 983         d1_zero = !TYPE_MAX_VALUE (d1);
 984         d2_zero = !TYPE_MAX_VALUE (d2);
 985
 986         d1_variable = (!d1_zero
 987                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 988                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 989         d2_variable = (!d2_zero
 990                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 991                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 992         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 993         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 994
 995         if (d1_variable || d2_variable)
 996           break;
 997         if (d1_zero && d2_zero)
 998           break;
 999         if (d1_zero || d2_zero
1000             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1001             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1002           val = 0;
1003
1004         break;
1005       }
1006
1007     case ENUMERAL_TYPE:
1008     case RECORD_TYPE:
1009     case UNION_TYPE:
1010       if (val != 1 && !same_translation_unit_p (t1, t2))
1011         {
1012           tree a1 = TYPE_ATTRIBUTES (t1);
1013           tree a2 = TYPE_ATTRIBUTES (t2);
1014
1015           if (! attribute_list_contained (a1, a2)
1016               && ! attribute_list_contained (a2, a1))
1017             break;
1018
1019           if (attrval != 2)
1020             return tagged_types_tu_compatible_p (t1, t2);
1021           val = tagged_types_tu_compatible_p (t1, t2);
1022         }
1023       break;
1024
1025     case VECTOR_TYPE:
1026       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1027             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1028       break;
1029
1030     default:
1031       break;
1032     }
1033   return attrval == 2 && val == 1 ? 2 : val;
1034 }
1035
1036 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1037    ignoring their qualifiers.  */
1038
1039 static int
1040 comp_target_types (tree ttl, tree ttr)
1041 {
1042   int val;
1043   tree mvl, mvr;
1044
1045   /* Do not lose qualifiers on element types of array types that are
1046      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1047   mvl = TREE_TYPE (ttl);
1048   mvr = TREE_TYPE (ttr);
1049   if (TREE_CODE (mvl) != ARRAY_TYPE)
1050     mvl = TYPE_MAIN_VARIANT (mvl);
1051   if (TREE_CODE (mvr) != ARRAY_TYPE)
1052     mvr = TYPE_MAIN_VARIANT (mvr);
1053   val = comptypes (mvl, mvr);
1054
1055   if (val == 2 && pedantic)
1056     pedwarn ("types are not quite compatible");
1057   return val;
1058 }
1059 \f
1060 /* Subroutines of `comptypes'.  */
1061
1062 /* Determine whether two trees derive from the same translation unit.
1063    If the CONTEXT chain ends in a null, that tree's context is still
1064    being parsed, so if two trees have context chains ending in null,
1065    they're in the same translation unit.  */
1066 int
1067 same_translation_unit_p (const_tree t1, const_tree t2)
1068 {
1069   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1070     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1071       {
1072       case tcc_declaration:
1073         t1 = DECL_CONTEXT (t1); break;
1074       case tcc_type:
1075         t1 = TYPE_CONTEXT (t1); break;
1076       case tcc_exceptional:
1077         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1078       default: gcc_unreachable ();
1079       }
1080
1081   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1082     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1083       {
1084       case tcc_declaration:
1085         t2 = DECL_CONTEXT (t2); break;
1086       case tcc_type:
1087         t2 = TYPE_CONTEXT (t2); break;
1088       case tcc_exceptional:
1089         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1090       default: gcc_unreachable ();
1091       }
1092
1093   return t1 == t2;
1094 }
1095
1096 /* Allocate the seen two types, assuming that they are compatible. */
1097
1098 static struct tagged_tu_seen_cache *
1099 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1100 {
1101   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1102   tu->next = tagged_tu_seen_base;
1103   tu->t1 = t1;
1104   tu->t2 = t2;
1105
1106   tagged_tu_seen_base = tu;
1107
1108   /* The C standard says that two structures in different translation
1109      units are compatible with each other only if the types of their
1110      fields are compatible (among other things).  We assume that they
1111      are compatible until proven otherwise when building the cache.
1112      An example where this can occur is:
1113      struct a
1114      {
1115        struct a *next;
1116      };
1117      If we are comparing this against a similar struct in another TU,
1118      and did not assume they were compatible, we end up with an infinite
1119      loop.  */
1120   tu->val = 1;
1121   return tu;
1122 }
1123
1124 /* Free the seen types until we get to TU_TIL. */
1125
1126 static void
1127 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1128 {
1129   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1130   while (tu != tu_til)
1131     {
1132       const struct tagged_tu_seen_cache *const tu1
1133         = (const struct tagged_tu_seen_cache *) tu;
1134       tu = tu1->next;
1135       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1136     }
1137   tagged_tu_seen_base = tu_til;
1138 }
1139
1140 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1141    compatible.  If the two types are not the same (which has been
1142    checked earlier), this can only happen when multiple translation
1143    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1144    rules.  */
1145
1146 static int
1147 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1148 {
1149   tree s1, s2;
1150   bool needs_warning = false;
1151
1152   /* We have to verify that the tags of the types are the same.  This
1153      is harder than it looks because this may be a typedef, so we have
1154      to go look at the original type.  It may even be a typedef of a
1155      typedef...
1156      In the case of compiler-created builtin structs the TYPE_DECL
1157      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1158   while (TYPE_NAME (t1)
1159          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1160          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1161     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1162
1163   while (TYPE_NAME (t2)
1164          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1165          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1166     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1167
1168   /* C90 didn't have the requirement that the two tags be the same.  */
1169   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1170     return 0;
1171
1172   /* C90 didn't say what happened if one or both of the types were
1173      incomplete; we choose to follow C99 rules here, which is that they
1174      are compatible.  */
1175   if (TYPE_SIZE (t1) == NULL
1176       || TYPE_SIZE (t2) == NULL)
1177     return 1;
1178
1179   {
1180     const struct tagged_tu_seen_cache * tts_i;
1181     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1182       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1183         return tts_i->val;
1184   }
1185
1186   switch (TREE_CODE (t1))
1187     {
1188     case ENUMERAL_TYPE:
1189       {
1190         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1191         /* Speed up the case where the type values are in the same order.  */
1192         tree tv1 = TYPE_VALUES (t1);
1193         tree tv2 = TYPE_VALUES (t2);
1194
1195         if (tv1 == tv2)
1196           {
1197             return 1;
1198           }
1199
1200         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1201           {
1202             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1203               break;
1204             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1205               {
1206                 tu->val = 0;
1207                 return 0;
1208               }
1209           }
1210
1211         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1212           {
1213             return 1;
1214           }
1215         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1216           {
1217             tu->val = 0;
1218             return 0;
1219           }
1220
1221         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1222           {
1223             tu->val = 0;
1224             return 0;
1225           }
1226
1227         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1228           {
1229             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1230             if (s2 == NULL
1231                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1232               {
1233                 tu->val = 0;
1234                 return 0;
1235               }
1236           }
1237         return 1;
1238       }
1239
1240     case UNION_TYPE:
1241       {
1242         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1243         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1244           {
1245             tu->val = 0;
1246             return 0;
1247           }
1248
1249         /*  Speed up the common case where the fields are in the same order. */
1250         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1251              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1252           {
1253             int result;
1254
1255             if (DECL_NAME (s1) != DECL_NAME (s2))
1256               break;
1257             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1258
1259             if (result != 1 && !DECL_NAME (s1))
1260               break;
1261             if (result == 0)
1262               {
1263                 tu->val = 0;
1264                 return 0;
1265               }
1266             if (result == 2)
1267               needs_warning = true;
1268
1269             if (TREE_CODE (s1) == FIELD_DECL
1270                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1271                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1272               {
1273                 tu->val = 0;
1274                 return 0;
1275               }
1276           }
1277         if (!s1 && !s2)
1278           {
1279             tu->val = needs_warning ? 2 : 1;
1280             return tu->val;
1281           }
1282
1283         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1284           {
1285             bool ok = false;
1286
1287             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1288               if (DECL_NAME (s1) == DECL_NAME (s2))
1289                 {
1290                   int result;
1291
1292                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1293
1294                   if (result != 1 && !DECL_NAME (s1))
1295                     continue;
1296                   if (result == 0)
1297                     {
1298                       tu->val = 0;
1299                       return 0;
1300                     }
1301                   if (result == 2)
1302                     needs_warning = true;
1303
1304                   if (TREE_CODE (s1) == FIELD_DECL
1305                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1306                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1307                     break;
1308
1309                   ok = true;
1310                   break;
1311                 }
1312             if (!ok)
1313               {
1314                 tu->val = 0;
1315                 return 0;
1316               }
1317           }
1318         tu->val = needs_warning ? 2 : 10;
1319         return tu->val;
1320       }
1321
1322     case RECORD_TYPE:
1323       {
1324         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1325
1326         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1327              s1 && s2;
1328              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1329           {
1330             int result;
1331             if (TREE_CODE (s1) != TREE_CODE (s2)
1332                 || DECL_NAME (s1) != DECL_NAME (s2))
1333               break;
1334             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1335             if (result == 0)
1336               break;
1337             if (result == 2)
1338               needs_warning = true;
1339
1340             if (TREE_CODE (s1) == FIELD_DECL
1341                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1342                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1343               break;
1344           }
1345         if (s1 && s2)
1346           tu->val = 0;
1347         else
1348           tu->val = needs_warning ? 2 : 1;
1349         return tu->val;
1350       }
1351
1352     default:
1353       gcc_unreachable ();
1354     }
1355 }
1356
1357 /* Return 1 if two function types F1 and F2 are compatible.
1358    If either type specifies no argument types,
1359    the other must specify a fixed number of self-promoting arg types.
1360    Otherwise, if one type specifies only the number of arguments,
1361    the other must specify that number of self-promoting arg types.
1362    Otherwise, the argument types must match.  */
1363
1364 static int
1365 function_types_compatible_p (const_tree f1, const_tree f2)
1366 {
1367   tree args1, args2;
1368   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1369   int val = 1;
1370   int val1;
1371   tree ret1, ret2;
1372
1373   ret1 = TREE_TYPE (f1);
1374   ret2 = TREE_TYPE (f2);
1375
1376   /* 'volatile' qualifiers on a function's return type used to mean
1377      the function is noreturn.  */
1378   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1379     pedwarn ("function return types not compatible due to %<volatile%>");
1380   if (TYPE_VOLATILE (ret1))
1381     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1382                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1383   if (TYPE_VOLATILE (ret2))
1384     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1385                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1386   val = comptypes_internal (ret1, ret2);
1387   if (val == 0)
1388     return 0;
1389
1390   args1 = TYPE_ARG_TYPES (f1);
1391   args2 = TYPE_ARG_TYPES (f2);
1392
1393   /* An unspecified parmlist matches any specified parmlist
1394      whose argument types don't need default promotions.  */
1395
1396   if (args1 == 0)
1397     {
1398       if (!self_promoting_args_p (args2))
1399         return 0;
1400       /* If one of these types comes from a non-prototype fn definition,
1401          compare that with the other type's arglist.
1402          If they don't match, ask for a warning (but no error).  */
1403       if (TYPE_ACTUAL_ARG_TYPES (f1)
1404           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1405         val = 2;
1406       return val;
1407     }
1408   if (args2 == 0)
1409     {
1410       if (!self_promoting_args_p (args1))
1411         return 0;
1412       if (TYPE_ACTUAL_ARG_TYPES (f2)
1413           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1414         val = 2;
1415       return val;
1416     }
1417
1418   /* Both types have argument lists: compare them and propagate results.  */
1419   val1 = type_lists_compatible_p (args1, args2);
1420   return val1 != 1 ? val1 : val;
1421 }
1422
1423 /* Check two lists of types for compatibility,
1424    returning 0 for incompatible, 1 for compatible,
1425    or 2 for compatible with warning.  */
1426
1427 static int
1428 type_lists_compatible_p (const_tree args1, const_tree args2)
1429 {
1430   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1431   int val = 1;
1432   int newval = 0;
1433
1434   while (1)
1435     {
1436       tree a1, mv1, a2, mv2;
1437       if (args1 == 0 && args2 == 0)
1438         return val;
1439       /* If one list is shorter than the other,
1440          they fail to match.  */
1441       if (args1 == 0 || args2 == 0)
1442         return 0;
1443       mv1 = a1 = TREE_VALUE (args1);
1444       mv2 = a2 = TREE_VALUE (args2);
1445       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1446         mv1 = TYPE_MAIN_VARIANT (mv1);
1447       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1448         mv2 = TYPE_MAIN_VARIANT (mv2);
1449       /* A null pointer instead of a type
1450          means there is supposed to be an argument
1451          but nothing is specified about what type it has.
1452          So match anything that self-promotes.  */
1453       if (a1 == 0)
1454         {
1455           if (c_type_promotes_to (a2) != a2)
1456             return 0;
1457         }
1458       else if (a2 == 0)
1459         {
1460           if (c_type_promotes_to (a1) != a1)
1461             return 0;
1462         }
1463       /* If one of the lists has an error marker, ignore this arg.  */
1464       else if (TREE_CODE (a1) == ERROR_MARK
1465                || TREE_CODE (a2) == ERROR_MARK)
1466         ;
1467       else if (!(newval = comptypes_internal (mv1, mv2)))
1468         {
1469           /* Allow  wait (union {union wait *u; int *i} *)
1470              and  wait (union wait *)  to be compatible.  */
1471           if (TREE_CODE (a1) == UNION_TYPE
1472               && (TYPE_NAME (a1) == 0
1473                   || TYPE_TRANSPARENT_UNION (a1))
1474               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1475               && tree_int_cst_equal (TYPE_SIZE (a1),
1476                                      TYPE_SIZE (a2)))
1477             {
1478               tree memb;
1479               for (memb = TYPE_FIELDS (a1);
1480                    memb; memb = TREE_CHAIN (memb))
1481                 {
1482                   tree mv3 = TREE_TYPE (memb);
1483                   if (mv3 && mv3 != error_mark_node
1484                       && TREE_CODE (mv3) != ARRAY_TYPE)
1485                     mv3 = TYPE_MAIN_VARIANT (mv3);
1486                   if (comptypes_internal (mv3, mv2))
1487                     break;
1488                 }
1489               if (memb == 0)
1490                 return 0;
1491             }
1492           else if (TREE_CODE (a2) == UNION_TYPE
1493                    && (TYPE_NAME (a2) == 0
1494                        || TYPE_TRANSPARENT_UNION (a2))
1495                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1496                    && tree_int_cst_equal (TYPE_SIZE (a2),
1497                                           TYPE_SIZE (a1)))
1498             {
1499               tree memb;
1500               for (memb = TYPE_FIELDS (a2);
1501                    memb; memb = TREE_CHAIN (memb))
1502                 {
1503                   tree mv3 = TREE_TYPE (memb);
1504                   if (mv3 && mv3 != error_mark_node
1505                       && TREE_CODE (mv3) != ARRAY_TYPE)
1506                     mv3 = TYPE_MAIN_VARIANT (mv3);
1507                   if (comptypes_internal (mv3, mv1))
1508                     break;
1509                 }
1510               if (memb == 0)
1511                 return 0;
1512             }
1513           else
1514             return 0;
1515         }
1516
1517       /* comptypes said ok, but record if it said to warn.  */
1518       if (newval > val)
1519         val = newval;
1520
1521       args1 = TREE_CHAIN (args1);
1522       args2 = TREE_CHAIN (args2);
1523     }
1524 }
1525 \f
1526 /* Compute the size to increment a pointer by.  */
1527
1528 static tree
1529 c_size_in_bytes (const_tree type)
1530 {
1531   enum tree_code code = TREE_CODE (type);
1532
1533   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1534     return size_one_node;
1535
1536   if (!COMPLETE_OR_VOID_TYPE_P (type))
1537     {
1538       error ("arithmetic on pointer to an incomplete type");
1539       return size_one_node;
1540     }
1541
1542   /* Convert in case a char is more than one unit.  */
1543   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1544                      size_int (TYPE_PRECISION (char_type_node)
1545                                / BITS_PER_UNIT));
1546 }
1547 \f
1548 /* Return either DECL or its known constant value (if it has one).  */
1549
1550 tree
1551 decl_constant_value (tree decl)
1552 {
1553   if (/* Don't change a variable array bound or initial value to a constant
1554          in a place where a variable is invalid.  Note that DECL_INITIAL
1555          isn't valid for a PARM_DECL.  */
1556       current_function_decl != 0
1557       && TREE_CODE (decl) != PARM_DECL
1558       && !TREE_THIS_VOLATILE (decl)
1559       && TREE_READONLY (decl)
1560       && DECL_INITIAL (decl) != 0
1561       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1562       /* This is invalid if initial value is not constant.
1563          If it has either a function call, a memory reference,
1564          or a variable, then re-evaluating it could give different results.  */
1565       && TREE_CONSTANT (DECL_INITIAL (decl))
1566       /* Check for cases where this is sub-optimal, even though valid.  */
1567       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1568     return DECL_INITIAL (decl);
1569   return decl;
1570 }
1571
1572 /* Return either DECL or its known constant value (if it has one), but
1573    return DECL if pedantic or DECL has mode BLKmode.  This is for
1574    bug-compatibility with the old behavior of decl_constant_value
1575    (before GCC 3.0); every use of this function is a bug and it should
1576    be removed before GCC 3.1.  It is not appropriate to use pedantic
1577    in a way that affects optimization, and BLKmode is probably not the
1578    right test for avoiding misoptimizations either.  */
1579
1580 static tree
1581 decl_constant_value_for_broken_optimization (tree decl)
1582 {
1583   tree ret;
1584
1585   if (pedantic || DECL_MODE (decl) == BLKmode)
1586     return decl;
1587
1588   ret = decl_constant_value (decl);
1589   /* Avoid unwanted tree sharing between the initializer and current
1590      function's body where the tree can be modified e.g. by the
1591      gimplifier.  */
1592   if (ret != decl && TREE_STATIC (decl))
1593     ret = unshare_expr (ret);
1594   return ret;
1595 }
1596
1597 /* Convert the array expression EXP to a pointer.  */
1598 static tree
1599 array_to_pointer_conversion (tree exp)
1600 {
1601   tree orig_exp = exp;
1602   tree type = TREE_TYPE (exp);
1603   tree adr;
1604   tree restype = TREE_TYPE (type);
1605   tree ptrtype;
1606
1607   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1608
1609   STRIP_TYPE_NOPS (exp);
1610
1611   if (TREE_NO_WARNING (orig_exp))
1612     TREE_NO_WARNING (exp) = 1;
1613
1614   ptrtype = build_pointer_type (restype);
1615
1616   if (TREE_CODE (exp) == INDIRECT_REF)
1617     return convert (ptrtype, TREE_OPERAND (exp, 0));
1618
1619   if (TREE_CODE (exp) == VAR_DECL)
1620     {
1621       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1622          ADDR_EXPR because it's the best way of representing what
1623          happens in C when we take the address of an array and place
1624          it in a pointer to the element type.  */
1625       adr = build1 (ADDR_EXPR, ptrtype, exp);
1626       if (!c_mark_addressable (exp))
1627         return error_mark_node;
1628       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1629       return adr;
1630     }
1631
1632   /* This way is better for a COMPONENT_REF since it can
1633      simplify the offset for a component.  */
1634   adr = build_unary_op (ADDR_EXPR, exp, 1);
1635   return convert (ptrtype, adr);
1636 }
1637
1638 /* Convert the function expression EXP to a pointer.  */
1639 static tree
1640 function_to_pointer_conversion (tree exp)
1641 {
1642   tree orig_exp = exp;
1643
1644   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1645
1646   STRIP_TYPE_NOPS (exp);
1647
1648   if (TREE_NO_WARNING (orig_exp))
1649     TREE_NO_WARNING (exp) = 1;
1650
1651   return build_unary_op (ADDR_EXPR, exp, 0);
1652 }
1653
1654 /* Perform the default conversion of arrays and functions to pointers.
1655    Return the result of converting EXP.  For any other expression, just
1656    return EXP after removing NOPs.  */
1657
1658 struct c_expr
1659 default_function_array_conversion (struct c_expr exp)
1660 {
1661   tree orig_exp = exp.value;
1662   tree type = TREE_TYPE (exp.value);
1663   enum tree_code code = TREE_CODE (type);
1664
1665   switch (code)
1666     {
1667     case ARRAY_TYPE:
1668       {
1669         bool not_lvalue = false;
1670         bool lvalue_array_p;
1671
1672         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1673                 || TREE_CODE (exp.value) == NOP_EXPR
1674                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1675                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1676           {
1677             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1678               not_lvalue = true;
1679             exp.value = TREE_OPERAND (exp.value, 0);
1680           }
1681
1682         if (TREE_NO_WARNING (orig_exp))
1683           TREE_NO_WARNING (exp.value) = 1;
1684
1685         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1686         if (!flag_isoc99 && !lvalue_array_p)
1687           {
1688             /* Before C99, non-lvalue arrays do not decay to pointers.
1689                Normally, using such an array would be invalid; but it can
1690                be used correctly inside sizeof or as a statement expression.
1691                Thus, do not give an error here; an error will result later.  */
1692             return exp;
1693           }
1694
1695         exp.value = array_to_pointer_conversion (exp.value);
1696       }
1697       break;
1698     case FUNCTION_TYPE:
1699       exp.value = function_to_pointer_conversion (exp.value);
1700       break;
1701     default:
1702       STRIP_TYPE_NOPS (exp.value);
1703       if (TREE_NO_WARNING (orig_exp))
1704         TREE_NO_WARNING (exp.value) = 1;
1705       break;
1706     }
1707
1708   return exp;
1709 }
1710
1711
1712 /* EXP is an expression of integer type.  Apply the integer promotions
1713    to it and return the promoted value.  */
1714
1715 tree
1716 perform_integral_promotions (tree exp)
1717 {
1718   tree type = TREE_TYPE (exp);
1719   enum tree_code code = TREE_CODE (type);
1720
1721   gcc_assert (INTEGRAL_TYPE_P (type));
1722
1723   /* Normally convert enums to int,
1724      but convert wide enums to something wider.  */
1725   if (code == ENUMERAL_TYPE)
1726     {
1727       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1728                                           TYPE_PRECISION (integer_type_node)),
1729                                      ((TYPE_PRECISION (type)
1730                                        >= TYPE_PRECISION (integer_type_node))
1731                                       && TYPE_UNSIGNED (type)));
1732
1733       return convert (type, exp);
1734     }
1735
1736   /* ??? This should no longer be needed now bit-fields have their
1737      proper types.  */
1738   if (TREE_CODE (exp) == COMPONENT_REF
1739       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1740       /* If it's thinner than an int, promote it like a
1741          c_promoting_integer_type_p, otherwise leave it alone.  */
1742       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1743                                TYPE_PRECISION (integer_type_node)))
1744     return convert (integer_type_node, exp);
1745
1746   if (c_promoting_integer_type_p (type))
1747     {
1748       /* Preserve unsignedness if not really getting any wider.  */
1749       if (TYPE_UNSIGNED (type)
1750           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1751         return convert (unsigned_type_node, exp);
1752
1753       return convert (integer_type_node, exp);
1754     }
1755
1756   return exp;
1757 }
1758
1759
1760 /* Perform default promotions for C data used in expressions.
1761    Enumeral types or short or char are converted to int.
1762    In addition, manifest constants symbols are replaced by their values.  */
1763
1764 tree
1765 default_conversion (tree exp)
1766 {
1767   tree orig_exp;
1768   tree type = TREE_TYPE (exp);
1769   enum tree_code code = TREE_CODE (type);
1770
1771   /* Functions and arrays have been converted during parsing.  */
1772   gcc_assert (code != FUNCTION_TYPE);
1773   if (code == ARRAY_TYPE)
1774     return exp;
1775
1776   /* Constants can be used directly unless they're not loadable.  */
1777   if (TREE_CODE (exp) == CONST_DECL)
1778     exp = DECL_INITIAL (exp);
1779
1780   /* Replace a nonvolatile const static variable with its value unless
1781      it is an array, in which case we must be sure that taking the
1782      address of the array produces consistent results.  */
1783   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1784     {
1785       exp = decl_constant_value_for_broken_optimization (exp);
1786       type = TREE_TYPE (exp);
1787     }
1788
1789   /* Strip no-op conversions.  */
1790   orig_exp = exp;
1791   STRIP_TYPE_NOPS (exp);
1792
1793   if (TREE_NO_WARNING (orig_exp))
1794     TREE_NO_WARNING (exp) = 1;
1795
1796   if (code == VOID_TYPE)
1797     {
1798       error ("void value not ignored as it ought to be");
1799       return error_mark_node;
1800     }
1801
1802   exp = require_complete_type (exp);
1803   if (exp == error_mark_node)
1804     return error_mark_node;
1805
1806   if (INTEGRAL_TYPE_P (type))
1807     return perform_integral_promotions (exp);
1808
1809   return exp;
1810 }
1811 \f
1812 /* Look up COMPONENT in a structure or union DECL.
1813
1814    If the component name is not found, returns NULL_TREE.  Otherwise,
1815    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1816    stepping down the chain to the component, which is in the last
1817    TREE_VALUE of the list.  Normally the list is of length one, but if
1818    the component is embedded within (nested) anonymous structures or
1819    unions, the list steps down the chain to the component.  */
1820
1821 static tree
1822 lookup_field (tree decl, tree component)
1823 {
1824   tree type = TREE_TYPE (decl);
1825   tree field;
1826
1827   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1828      to the field elements.  Use a binary search on this array to quickly
1829      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1830      will always be set for structures which have many elements.  */
1831
1832   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1833     {
1834       int bot, top, half;
1835       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1836
1837       field = TYPE_FIELDS (type);
1838       bot = 0;
1839       top = TYPE_LANG_SPECIFIC (type)->s->len;
1840       while (top - bot > 1)
1841         {
1842           half = (top - bot + 1) >> 1;
1843           field = field_array[bot+half];
1844
1845           if (DECL_NAME (field) == NULL_TREE)
1846             {
1847               /* Step through all anon unions in linear fashion.  */
1848               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1849                 {
1850                   field = field_array[bot++];
1851                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1852                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1853                     {
1854                       tree anon = lookup_field (field, component);
1855
1856                       if (anon)
1857                         return tree_cons (NULL_TREE, field, anon);
1858                     }
1859                 }
1860
1861               /* Entire record is only anon unions.  */
1862               if (bot > top)
1863                 return NULL_TREE;
1864
1865               /* Restart the binary search, with new lower bound.  */
1866               continue;
1867             }
1868
1869           if (DECL_NAME (field) == component)
1870             break;
1871           if (DECL_NAME (field) < component)
1872             bot += half;
1873           else
1874             top = bot + half;
1875         }
1876
1877       if (DECL_NAME (field_array[bot]) == component)
1878         field = field_array[bot];
1879       else if (DECL_NAME (field) != component)
1880         return NULL_TREE;
1881     }
1882   else
1883     {
1884       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1885         {
1886           if (DECL_NAME (field) == NULL_TREE
1887               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1888                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1889             {
1890               tree anon = lookup_field (field, component);
1891
1892               if (anon)
1893                 return tree_cons (NULL_TREE, field, anon);
1894             }
1895
1896           if (DECL_NAME (field) == component)
1897             break;
1898         }
1899
1900       if (field == NULL_TREE)
1901         return NULL_TREE;
1902     }
1903
1904   return tree_cons (NULL_TREE, field, NULL_TREE);
1905 }
1906
1907 /* Make an expression to refer to the COMPONENT field of
1908    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1909
1910 tree
1911 build_component_ref (tree datum, tree component)
1912 {
1913   tree type = TREE_TYPE (datum);
1914   enum tree_code code = TREE_CODE (type);
1915   tree field = NULL;
1916   tree ref;
1917
1918   if (!objc_is_public (datum, component))
1919     return error_mark_node;
1920
1921   /* See if there is a field or component with name COMPONENT.  */
1922
1923   if (code == RECORD_TYPE || code == UNION_TYPE)
1924     {
1925       if (!COMPLETE_TYPE_P (type))
1926         {
1927           c_incomplete_type_error (NULL_TREE, type);
1928           return error_mark_node;
1929         }
1930
1931       field = lookup_field (datum, component);
1932
1933       if (!field)
1934         {
1935           error ("%qT has no member named %qE", type, component);
1936           return error_mark_node;
1937         }
1938
1939       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1940          This might be better solved in future the way the C++ front
1941          end does it - by giving the anonymous entities each a
1942          separate name and type, and then have build_component_ref
1943          recursively call itself.  We can't do that here.  */
1944       do
1945         {
1946           tree subdatum = TREE_VALUE (field);
1947           int quals;
1948           tree subtype;
1949
1950           if (TREE_TYPE (subdatum) == error_mark_node)
1951             return error_mark_node;
1952
1953           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1954           quals |= TYPE_QUALS (TREE_TYPE (datum));
1955           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1956
1957           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1958                         NULL_TREE);
1959           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1960             TREE_READONLY (ref) = 1;
1961           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1962             TREE_THIS_VOLATILE (ref) = 1;
1963
1964           if (TREE_DEPRECATED (subdatum))
1965             warn_deprecated_use (subdatum);
1966
1967           datum = ref;
1968
1969           field = TREE_CHAIN (field);
1970         }
1971       while (field);
1972
1973       return ref;
1974     }
1975   else if (code != ERROR_MARK)
1976     error ("request for member %qE in something not a structure or union",
1977            component);
1978
1979   return error_mark_node;
1980 }
1981 \f
1982 /* Given an expression PTR for a pointer, return an expression
1983    for the value pointed to.
1984    ERRORSTRING is the name of the operator to appear in error messages.  */
1985
1986 tree
1987 build_indirect_ref (tree ptr, const char *errorstring)
1988 {
1989   tree pointer = default_conversion (ptr);
1990   tree type = TREE_TYPE (pointer);
1991
1992   if (TREE_CODE (type) == POINTER_TYPE)
1993     {
1994       if (TREE_CODE (pointer) == CONVERT_EXPR
1995           || TREE_CODE (pointer) == NOP_EXPR
1996           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1997         {
1998           /* If a warning is issued, mark it to avoid duplicates from
1999              the backend.  This only needs to be done at
2000              warn_strict_aliasing > 2.  */
2001           if (warn_strict_aliasing > 2)
2002             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2003                                          type, TREE_OPERAND (pointer, 0)))
2004               TREE_NO_WARNING (pointer) = 1;
2005         }
2006
2007       if (TREE_CODE (pointer) == ADDR_EXPR
2008           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2009               == TREE_TYPE (type)))
2010         return TREE_OPERAND (pointer, 0);
2011       else
2012         {
2013           tree t = TREE_TYPE (type);
2014           tree ref;
2015
2016           ref = build1 (INDIRECT_REF, t, pointer);
2017
2018           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2019             {
2020               error ("dereferencing pointer to incomplete type");
2021               return error_mark_node;
2022             }
2023           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2024             warning (0, "dereferencing %<void *%> pointer");
2025
2026           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2027              so that we get the proper error message if the result is used
2028              to assign to.  Also, &* is supposed to be a no-op.
2029              And ANSI C seems to specify that the type of the result
2030              should be the const type.  */
2031           /* A de-reference of a pointer to const is not a const.  It is valid
2032              to change it via some other pointer.  */
2033           TREE_READONLY (ref) = TYPE_READONLY (t);
2034           TREE_SIDE_EFFECTS (ref)
2035             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2036           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2037           return ref;
2038         }
2039     }
2040   else if (TREE_CODE (pointer) != ERROR_MARK)
2041     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2042   return error_mark_node;
2043 }
2044
2045 /* Like c_mark_addressable but don't check register qualifier.  */
2046 static void
2047 mark_addressable_vector (tree x)
2048 {
2049   while (handled_component_p (x))
2050     x = TREE_OPERAND (x, 0);
2051   if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
2052     return ;
2053   TREE_ADDRESSABLE (x) = 1;
2054 }
2055
2056 /* This handles expressions of the form "a[i]", which denotes
2057    an array reference.
2058
2059    This is logically equivalent in C to *(a+i), but we may do it differently.
2060    If A is a variable or a member, we generate a primitive ARRAY_REF.
2061    This avoids forcing the array out of registers, and can work on
2062    arrays that are not lvalues (for example, members of structures returned
2063    by functions).
2064
2065    For vector types, allow vector[i] but not i[vector], and create
2066    *(((type*)&vectortype) + i) for the expression.  */
2067
2068 tree
2069 build_array_ref (tree array, tree index)
2070 {
2071   bool swapped = false;
2072   if (TREE_TYPE (array) == error_mark_node
2073       || TREE_TYPE (index) == error_mark_node)
2074     return error_mark_node;
2075
2076   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2077       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE
2078       /* Allow vector[index] but not index[vector].  */
2079       && TREE_CODE (TREE_TYPE (array)) != VECTOR_TYPE)
2080     {
2081       tree temp;
2082       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2083           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2084         {
2085           error ("subscripted value is not an array, a pointer, or a vector");
2086           return error_mark_node;
2087         }
2088       temp = array;
2089       array = index;
2090       index = temp;
2091       swapped = true;
2092     }
2093
2094   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2095     {
2096       error ("array subscript is not an integer");
2097       return error_mark_node;
2098     }
2099
2100   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2101     {
2102       error ("subscripted value is pointer to function");
2103       return error_mark_node;
2104     }
2105
2106   /* ??? Existing practice has been to warn only when the char
2107      index is syntactically the index, not for char[array].  */
2108   if (!swapped)
2109      warn_array_subscript_with_type_char (index);
2110
2111   /* Apply default promotions *after* noticing character types.  */
2112   index = default_conversion (index);
2113
2114   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2115
2116   /* For vector[index], convert the vector to a pointer of the underlying
2117      type. */
2118   if (TREE_CODE (TREE_TYPE (array)) == VECTOR_TYPE)
2119     {
2120       tree type = TREE_TYPE (array);
2121       tree type1;
2122       /* Mark the vector as addressable but ignore the
2123          register storage class.  */
2124       mark_addressable_vector (array);
2125       type = build_qualified_type (TREE_TYPE (type), TYPE_QUALS (type));
2126       type = build_pointer_type (type);
2127       type1 = build_pointer_type (TREE_TYPE (array));
2128       array = build1 (ADDR_EXPR, type1, array);
2129       array = convert (type, array);
2130     }
2131
2132   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2133     {
2134       tree rval, type;
2135
2136       /* An array that is indexed by a non-constant
2137          cannot be stored in a register; we must be able to do
2138          address arithmetic on its address.
2139          Likewise an array of elements of variable size.  */
2140       if (TREE_CODE (index) != INTEGER_CST
2141           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2142               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2143         {
2144           if (!c_mark_addressable (array))
2145             return error_mark_node;
2146         }
2147       /* An array that is indexed by a constant value which is not within
2148          the array bounds cannot be stored in a register either; because we
2149          would get a crash in store_bit_field/extract_bit_field when trying
2150          to access a non-existent part of the register.  */
2151       if (TREE_CODE (index) == INTEGER_CST
2152           && TYPE_DOMAIN (TREE_TYPE (array))
2153           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2154         {
2155           if (!c_mark_addressable (array))
2156             return error_mark_node;
2157         }
2158
2159       if (pedantic)
2160         {
2161           tree foo = array;
2162           while (TREE_CODE (foo) == COMPONENT_REF)
2163             foo = TREE_OPERAND (foo, 0);
2164           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2165             pedwarn ("ISO C forbids subscripting %<register%> array");
2166           else if (!flag_isoc99 && !lvalue_p (foo))
2167             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2168         }
2169
2170       type = TREE_TYPE (TREE_TYPE (array));
2171       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2172       /* Array ref is const/volatile if the array elements are
2173          or if the array is.  */
2174       TREE_READONLY (rval)
2175         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2176             | TREE_READONLY (array));
2177       TREE_SIDE_EFFECTS (rval)
2178         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2179             | TREE_SIDE_EFFECTS (array));
2180       TREE_THIS_VOLATILE (rval)
2181         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2182             /* This was added by rms on 16 Nov 91.
2183                It fixes  vol struct foo *a;  a->elts[1]
2184                in an inline function.
2185                Hope it doesn't break something else.  */
2186             | TREE_THIS_VOLATILE (array));
2187       return require_complete_type (fold (rval));
2188     }
2189   else
2190     {
2191       tree ar = default_conversion (array);
2192
2193       if (ar == error_mark_node)
2194         return ar;
2195
2196       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2197       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2198
2199       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2200                                  "array indexing");
2201     }
2202 }
2203 \f
2204 /* Build an external reference to identifier ID.  FUN indicates
2205    whether this will be used for a function call.  LOC is the source
2206    location of the identifier.  */
2207 tree
2208 build_external_ref (tree id, int fun, location_t loc)
2209 {
2210   tree ref;
2211   tree decl = lookup_name (id);
2212
2213   /* In Objective-C, an instance variable (ivar) may be preferred to
2214      whatever lookup_name() found.  */
2215   decl = objc_lookup_ivar (decl, id);
2216
2217   if (decl && decl != error_mark_node)
2218     ref = decl;
2219   else if (fun)
2220     /* Implicit function declaration.  */
2221     ref = implicitly_declare (id);
2222   else if (decl == error_mark_node)
2223     /* Don't complain about something that's already been
2224        complained about.  */
2225     return error_mark_node;
2226   else
2227     {
2228       undeclared_variable (id, loc);
2229       return error_mark_node;
2230     }
2231
2232   if (TREE_TYPE (ref) == error_mark_node)
2233     return error_mark_node;
2234
2235   if (TREE_DEPRECATED (ref))
2236     warn_deprecated_use (ref);
2237
2238   /* Recursive call does not count as usage.  */
2239   if (ref != current_function_decl)
2240     {
2241       if (!skip_evaluation)
2242         assemble_external (ref);
2243       TREE_USED (ref) = 1;
2244     }
2245
2246   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2247     {
2248       if (!in_sizeof && !in_typeof)
2249         C_DECL_USED (ref) = 1;
2250       else if (DECL_INITIAL (ref) == 0
2251                && DECL_EXTERNAL (ref)
2252                && !TREE_PUBLIC (ref))
2253         record_maybe_used_decl (ref);
2254     }
2255
2256   if (TREE_CODE (ref) == CONST_DECL)
2257     {
2258       used_types_insert (TREE_TYPE (ref));
2259       ref = DECL_INITIAL (ref);
2260       TREE_CONSTANT (ref) = 1;
2261       TREE_INVARIANT (ref) = 1;
2262     }
2263   else if (current_function_decl != 0
2264            && !DECL_FILE_SCOPE_P (current_function_decl)
2265            && (TREE_CODE (ref) == VAR_DECL
2266                || TREE_CODE (ref) == PARM_DECL
2267                || TREE_CODE (ref) == FUNCTION_DECL))
2268     {
2269       tree context = decl_function_context (ref);
2270
2271       if (context != 0 && context != current_function_decl)
2272         DECL_NONLOCAL (ref) = 1;
2273     }
2274   /* C99 6.7.4p3: An inline definition of a function with external
2275      linkage ... shall not contain a reference to an identifier with
2276      internal linkage.  */
2277   else if (current_function_decl != 0
2278            && DECL_DECLARED_INLINE_P (current_function_decl)
2279            && DECL_EXTERNAL (current_function_decl)
2280            && VAR_OR_FUNCTION_DECL_P (ref)
2281            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2282            && ! TREE_PUBLIC (ref)
2283            && DECL_CONTEXT (ref) != current_function_decl)
2284     pedwarn ("%H%qD is static but used in inline function %qD "
2285              "which is not static", &loc, ref, current_function_decl);
2286
2287   return ref;
2288 }
2289
2290 /* Record details of decls possibly used inside sizeof or typeof.  */
2291 struct maybe_used_decl
2292 {
2293   /* The decl.  */
2294   tree decl;
2295   /* The level seen at (in_sizeof + in_typeof).  */
2296   int level;
2297   /* The next one at this level or above, or NULL.  */
2298   struct maybe_used_decl *next;
2299 };
2300
2301 static struct maybe_used_decl *maybe_used_decls;
2302
2303 /* Record that DECL, an undefined static function reference seen
2304    inside sizeof or typeof, might be used if the operand of sizeof is
2305    a VLA type or the operand of typeof is a variably modified
2306    type.  */
2307
2308 static void
2309 record_maybe_used_decl (tree decl)
2310 {
2311   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2312   t->decl = decl;
2313   t->level = in_sizeof + in_typeof;
2314   t->next = maybe_used_decls;
2315   maybe_used_decls = t;
2316 }
2317
2318 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2319    USED is false, just discard them.  If it is true, mark them used
2320    (if no longer inside sizeof or typeof) or move them to the next
2321    level up (if still inside sizeof or typeof).  */
2322
2323 void
2324 pop_maybe_used (bool used)
2325 {
2326   struct maybe_used_decl *p = maybe_used_decls;
2327   int cur_level = in_sizeof + in_typeof;
2328   while (p && p->level > cur_level)
2329     {
2330       if (used)
2331         {
2332           if (cur_level == 0)
2333             C_DECL_USED (p->decl) = 1;
2334           else
2335             p->level = cur_level;
2336         }
2337       p = p->next;
2338     }
2339   if (!used || cur_level == 0)
2340     maybe_used_decls = p;
2341 }
2342
2343 /* Return the result of sizeof applied to EXPR.  */
2344
2345 struct c_expr
2346 c_expr_sizeof_expr (struct c_expr expr)
2347 {
2348   struct c_expr ret;
2349   if (expr.value == error_mark_node)
2350     {
2351       ret.value = error_mark_node;
2352       ret.original_code = ERROR_MARK;
2353       pop_maybe_used (false);
2354     }
2355   else
2356     {
2357       ret.value = c_sizeof (TREE_TYPE (expr.value));
2358       ret.original_code = ERROR_MARK;
2359       if (c_vla_type_p (TREE_TYPE (expr.value)))
2360         {
2361           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2362           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2363         }
2364       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2365     }
2366   return ret;
2367 }
2368
2369 /* Return the result of sizeof applied to T, a structure for the type
2370    name passed to sizeof (rather than the type itself).  */
2371
2372 struct c_expr
2373 c_expr_sizeof_type (struct c_type_name *t)
2374 {
2375   tree type;
2376   struct c_expr ret;
2377   type = groktypename (t);
2378   ret.value = c_sizeof (type);
2379   ret.original_code = ERROR_MARK;
2380   pop_maybe_used (type != error_mark_node
2381                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2382   return ret;
2383 }
2384
2385 /* Build a function call to function FUNCTION with parameters PARAMS.
2386    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2387    TREE_VALUE of each node is a parameter-expression.
2388    FUNCTION's data type may be a function type or a pointer-to-function.  */
2389
2390 tree
2391 build_function_call (tree function, tree params)
2392 {
2393   tree fntype, fundecl = 0;
2394   tree name = NULL_TREE, result;
2395   tree tem;
2396   int nargs;
2397   tree *argarray;
2398
2399
2400   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2401   STRIP_TYPE_NOPS (function);
2402
2403   /* Convert anything with function type to a pointer-to-function.  */
2404   if (TREE_CODE (function) == FUNCTION_DECL)
2405     {
2406       /* Implement type-directed function overloading for builtins.
2407          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2408          handle all the type checking.  The result is a complete expression
2409          that implements this function call.  */
2410       tem = resolve_overloaded_builtin (function, params);
2411       if (tem)
2412         return tem;
2413
2414       name = DECL_NAME (function);
2415       fundecl = function;
2416     }
2417   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2418     function = function_to_pointer_conversion (function);
2419
2420   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2421      expressions, like those used for ObjC messenger dispatches.  */
2422   function = objc_rewrite_function_call (function, params);
2423
2424   fntype = TREE_TYPE (function);
2425
2426   if (TREE_CODE (fntype) == ERROR_MARK)
2427     return error_mark_node;
2428
2429   if (!(TREE_CODE (fntype) == POINTER_TYPE
2430         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2431     {
2432       error ("called object %qE is not a function", function);
2433       return error_mark_node;
2434     }
2435
2436   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2437     current_function_returns_abnormally = 1;
2438
2439   /* fntype now gets the type of function pointed to.  */
2440   fntype = TREE_TYPE (fntype);
2441
2442   /* Check that the function is called through a compatible prototype.
2443      If it is not, replace the call by a trap, wrapped up in a compound
2444      expression if necessary.  This has the nice side-effect to prevent
2445      the tree-inliner from generating invalid assignment trees which may
2446      blow up in the RTL expander later.  */
2447   if ((TREE_CODE (function) == NOP_EXPR
2448        || TREE_CODE (function) == CONVERT_EXPR)
2449       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2450       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2451       && !comptypes (fntype, TREE_TYPE (tem)))
2452     {
2453       tree return_type = TREE_TYPE (fntype);
2454       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2455                                        NULL_TREE);
2456
2457       /* This situation leads to run-time undefined behavior.  We can't,
2458          therefore, simply error unless we can prove that all possible
2459          executions of the program must execute the code.  */
2460       warning (0, "function called through a non-compatible type");
2461
2462       /* We can, however, treat "undefined" any way we please.
2463          Call abort to encourage the user to fix the program.  */
2464       inform ("if this code is reached, the program will abort");
2465
2466       if (VOID_TYPE_P (return_type))
2467         return trap;
2468       else
2469         {
2470           tree rhs;
2471
2472           if (AGGREGATE_TYPE_P (return_type))
2473             rhs = build_compound_literal (return_type,
2474                                           build_constructor (return_type, 0));
2475           else
2476             rhs = fold_convert (return_type, integer_zero_node);
2477
2478           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2479         }
2480     }
2481
2482   /* Convert the parameters to the types declared in the
2483      function prototype, or apply default promotions.  */
2484
2485   nargs = list_length (params);
2486   argarray = (tree *) alloca (nargs * sizeof (tree));
2487   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2488                              params, function, fundecl);
2489   if (nargs < 0)
2490     return error_mark_node;
2491
2492   /* Check that the arguments to the function are valid.  */
2493
2494   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2495                             TYPE_ARG_TYPES (fntype));
2496
2497   if (require_constant_value)
2498     {
2499       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2500                                                   function, nargs, argarray);
2501       if (TREE_CONSTANT (result)
2502           && (name == NULL_TREE
2503               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2504         pedwarn_init ("initializer element is not constant");
2505     }
2506   else
2507     result = fold_build_call_array (TREE_TYPE (fntype),
2508                                     function, nargs, argarray);
2509
2510   if (VOID_TYPE_P (TREE_TYPE (result)))
2511     return result;
2512   return require_complete_type (result);
2513 }
2514 \f
2515 /* Convert the argument expressions in the list VALUES
2516    to the types in the list TYPELIST.  The resulting arguments are
2517    stored in the array ARGARRAY which has size NARGS.
2518
2519    If TYPELIST is exhausted, or when an element has NULL as its type,
2520    perform the default conversions.
2521
2522    PARMLIST is the chain of parm decls for the function being called.
2523    It may be 0, if that info is not available.
2524    It is used only for generating error messages.
2525
2526    FUNCTION is a tree for the called function.  It is used only for
2527    error messages, where it is formatted with %qE.
2528
2529    This is also where warnings about wrong number of args are generated.
2530
2531    VALUES is a chain of TREE_LIST nodes with the elements of the list
2532    in the TREE_VALUE slots of those nodes.
2533
2534    Returns the actual number of arguments processed (which may be less
2535    than NARGS in some error situations), or -1 on failure.  */
2536
2537 static int
2538 convert_arguments (int nargs, tree *argarray,
2539                    tree typelist, tree values, tree function, tree fundecl)
2540 {
2541   tree typetail, valtail;
2542   int parmnum;
2543   const bool type_generic = fundecl
2544     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2545   tree selector;
2546
2547   /* Change pointer to function to the function itself for
2548      diagnostics.  */
2549   if (TREE_CODE (function) == ADDR_EXPR
2550       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2551     function = TREE_OPERAND (function, 0);
2552
2553   /* Handle an ObjC selector specially for diagnostics.  */
2554   selector = objc_message_selector ();
2555
2556   /* Scan the given expressions and types, producing individual
2557      converted arguments and storing them in ARGARRAY.  */
2558
2559   for (valtail = values, typetail = typelist, parmnum = 0;
2560        valtail;
2561        valtail = TREE_CHAIN (valtail), parmnum++)
2562     {
2563       tree type = typetail ? TREE_VALUE (typetail) : 0;
2564       tree val = TREE_VALUE (valtail);
2565       tree rname = function;
2566       int argnum = parmnum + 1;
2567       const char *invalid_func_diag;
2568
2569       if (type == void_type_node)
2570         {
2571           error ("too many arguments to function %qE", function);
2572           return parmnum;
2573         }
2574
2575       if (selector && argnum > 2)
2576         {
2577           rname = selector;
2578           argnum -= 2;
2579         }
2580
2581       STRIP_TYPE_NOPS (val);
2582
2583       val = require_complete_type (val);
2584
2585       if (type != 0)
2586         {
2587           /* Formal parm type is specified by a function prototype.  */
2588           tree parmval;
2589
2590           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2591             {
2592               error ("type of formal parameter %d is incomplete", parmnum + 1);
2593               parmval = val;
2594             }
2595           else
2596             {
2597               /* Optionally warn about conversions that
2598                  differ from the default conversions.  */
2599               if (warn_traditional_conversion || warn_traditional)
2600                 {
2601                   unsigned int formal_prec = TYPE_PRECISION (type);
2602
2603                   if (INTEGRAL_TYPE_P (type)
2604                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2605                     warning (0, "passing argument %d of %qE as integer "
2606                              "rather than floating due to prototype",
2607                              argnum, rname);
2608                   if (INTEGRAL_TYPE_P (type)
2609                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2610                     warning (0, "passing argument %d of %qE as integer "
2611                              "rather than complex due to prototype",
2612                              argnum, rname);
2613                   else if (TREE_CODE (type) == COMPLEX_TYPE
2614                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2615                     warning (0, "passing argument %d of %qE as complex "
2616                              "rather than floating due to prototype",
2617                              argnum, rname);
2618                   else if (TREE_CODE (type) == REAL_TYPE
2619                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2620                     warning (0, "passing argument %d of %qE as floating "
2621                              "rather than integer due to prototype",
2622                              argnum, rname);
2623                   else if (TREE_CODE (type) == COMPLEX_TYPE
2624                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2625                     warning (0, "passing argument %d of %qE as complex "
2626                              "rather than integer due to prototype",
2627                              argnum, rname);
2628                   else if (TREE_CODE (type) == REAL_TYPE
2629                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2630                     warning (0, "passing argument %d of %qE as floating "
2631                              "rather than complex due to prototype",
2632                              argnum, rname);
2633                   /* ??? At some point, messages should be written about
2634                      conversions between complex types, but that's too messy
2635                      to do now.  */
2636                   else if (TREE_CODE (type) == REAL_TYPE
2637                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2638                     {
2639                       /* Warn if any argument is passed as `float',
2640                          since without a prototype it would be `double'.  */
2641                       if (formal_prec == TYPE_PRECISION (float_type_node)
2642                           && type != dfloat32_type_node)
2643                         warning (0, "passing argument %d of %qE as %<float%> "
2644                                  "rather than %<double%> due to prototype",
2645                                  argnum, rname);
2646
2647                       /* Warn if mismatch between argument and prototype
2648                          for decimal float types.  Warn of conversions with
2649                          binary float types and of precision narrowing due to
2650                          prototype. */
2651                       else if (type != TREE_TYPE (val)
2652                                && (type == dfloat32_type_node
2653                                    || type == dfloat64_type_node
2654                                    || type == dfloat128_type_node
2655                                    || TREE_TYPE (val) == dfloat32_type_node
2656                                    || TREE_TYPE (val) == dfloat64_type_node
2657                                    || TREE_TYPE (val) == dfloat128_type_node)
2658                                && (formal_prec
2659                                    <= TYPE_PRECISION (TREE_TYPE (val))
2660                                    || (type == dfloat128_type_node
2661                                        && (TREE_TYPE (val)
2662                                            != dfloat64_type_node
2663                                            && (TREE_TYPE (val)
2664                                                != dfloat32_type_node)))
2665                                    || (type == dfloat64_type_node
2666                                        && (TREE_TYPE (val)
2667                                            != dfloat32_type_node))))
2668                         warning (0, "passing argument %d of %qE as %qT "
2669                                  "rather than %qT due to prototype",
2670                                  argnum, rname, type, TREE_TYPE (val));
2671
2672                     }
2673                   /* Detect integer changing in width or signedness.
2674                      These warnings are only activated with
2675                      -Wtraditional-conversion, not with -Wtraditional.  */
2676                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2677                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2678                     {
2679                       tree would_have_been = default_conversion (val);
2680                       tree type1 = TREE_TYPE (would_have_been);
2681
2682                       if (TREE_CODE (type) == ENUMERAL_TYPE
2683                           && (TYPE_MAIN_VARIANT (type)
2684                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2685                         /* No warning if function asks for enum
2686                            and the actual arg is that enum type.  */
2687                         ;
2688                       else if (formal_prec != TYPE_PRECISION (type1))
2689                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2690                                  "with different width due to prototype",
2691                                  argnum, rname);
2692                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2693                         ;
2694                       /* Don't complain if the formal parameter type
2695                          is an enum, because we can't tell now whether
2696                          the value was an enum--even the same enum.  */
2697                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2698                         ;
2699                       else if (TREE_CODE (val) == INTEGER_CST
2700                                && int_fits_type_p (val, type))
2701                         /* Change in signedness doesn't matter
2702                            if a constant value is unaffected.  */
2703                         ;
2704                       /* If the value is extended from a narrower
2705                          unsigned type, it doesn't matter whether we
2706                          pass it as signed or unsigned; the value
2707                          certainly is the same either way.  */
2708                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2709                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2710                         ;
2711                       else if (TYPE_UNSIGNED (type))
2712                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2713                                  "as unsigned due to prototype",
2714                                  argnum, rname);
2715                       else
2716                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2717                                  "as signed due to prototype", argnum, rname);
2718                     }
2719                 }
2720
2721               parmval = convert_for_assignment (type, val, ic_argpass,
2722                                                 fundecl, function,
2723                                                 parmnum + 1);
2724
2725               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2726                   && INTEGRAL_TYPE_P (type)
2727                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2728                 parmval = default_conversion (parmval);
2729             }
2730           argarray[parmnum] = parmval;
2731         }
2732       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2733                && (TYPE_PRECISION (TREE_TYPE (val))
2734                    < TYPE_PRECISION (double_type_node))
2735                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2736         {
2737           if (type_generic)
2738             argarray[parmnum] = val;
2739           else
2740             /* Convert `float' to `double'.  */
2741             argarray[parmnum] = convert (double_type_node, val);
2742         }
2743       else if ((invalid_func_diag =
2744                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2745         {
2746           error (invalid_func_diag);
2747           return -1;
2748         }
2749       else
2750         /* Convert `short' and `char' to full-size `int'.  */
2751         argarray[parmnum] = default_conversion (val);
2752
2753       if (typetail)
2754         typetail = TREE_CHAIN (typetail);
2755     }
2756
2757   gcc_assert (parmnum == nargs);
2758
2759   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2760     {
2761       error ("too few arguments to function %qE", function);
2762       return -1;
2763     }
2764
2765   return parmnum;
2766 }
2767 \f
2768 /* This is the entry point used by the parser to build unary operators
2769    in the input.  CODE, a tree_code, specifies the unary operator, and
2770    ARG is the operand.  For unary plus, the C parser currently uses
2771    CONVERT_EXPR for code.  */
2772
2773 struct c_expr
2774 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2775 {
2776   struct c_expr result;
2777
2778   result.original_code = ERROR_MARK;
2779   result.value = build_unary_op (code, arg.value, 0);
2780
2781   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2782     overflow_warning (result.value);
2783
2784   return result;
2785 }
2786
2787 /* This is the entry point used by the parser to build binary operators
2788    in the input.  CODE, a tree_code, specifies the binary operator, and
2789    ARG1 and ARG2 are the operands.  In addition to constructing the
2790    expression, we check for operands that were written with other binary
2791    operators in a way that is likely to confuse the user.  */
2792
2793 struct c_expr
2794 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2795                         struct c_expr arg2)
2796 {
2797   struct c_expr result;
2798
2799   enum tree_code code1 = arg1.original_code;
2800   enum tree_code code2 = arg2.original_code;
2801
2802   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2803   result.original_code = code;
2804
2805   if (TREE_CODE (result.value) == ERROR_MARK)
2806     return result;
2807
2808   /* Check for cases such as x+y<<z which users are likely
2809      to misinterpret.  */
2810   if (warn_parentheses)
2811     warn_about_parentheses (code, code1, code2);
2812
2813   if (code1 != tcc_comparison)
2814     warn_logical_operator (code, arg1.value, arg2.value);
2815
2816   /* Warn about comparisons against string literals, with the exception
2817      of testing for equality or inequality of a string literal with NULL.  */
2818   if (code == EQ_EXPR || code == NE_EXPR)
2819     {
2820       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2821           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2822         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2823     }
2824   else if (TREE_CODE_CLASS (code) == tcc_comparison
2825            && (code1 == STRING_CST || code2 == STRING_CST))
2826     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2827
2828   if (TREE_OVERFLOW_P (result.value)
2829       && !TREE_OVERFLOW_P (arg1.value)
2830       && !TREE_OVERFLOW_P (arg2.value))
2831     overflow_warning (result.value);
2832
2833   return result;
2834 }
2835 \f
2836 /* Return a tree for the difference of pointers OP0 and OP1.
2837    The resulting tree has type int.  */
2838
2839 static tree
2840 pointer_diff (tree op0, tree op1)
2841 {
2842   tree restype = ptrdiff_type_node;
2843
2844   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2845   tree con0, con1, lit0, lit1;
2846   tree orig_op1 = op1;
2847
2848   if (pedantic || warn_pointer_arith)
2849     {
2850       if (TREE_CODE (target_type) == VOID_TYPE)
2851         pedwarn ("pointer of type %<void *%> used in subtraction");
2852       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2853         pedwarn ("pointer to a function used in subtraction");
2854     }
2855
2856   /* If the conversion to ptrdiff_type does anything like widening or
2857      converting a partial to an integral mode, we get a convert_expression
2858      that is in the way to do any simplifications.
2859      (fold-const.c doesn't know that the extra bits won't be needed.
2860      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2861      different mode in place.)
2862      So first try to find a common term here 'by hand'; we want to cover
2863      at least the cases that occur in legal static initializers.  */
2864   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2865       && (TYPE_PRECISION (TREE_TYPE (op0))
2866           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2867     con0 = TREE_OPERAND (op0, 0);
2868   else
2869     con0 = op0;
2870   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2871       && (TYPE_PRECISION (TREE_TYPE (op1))
2872           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2873     con1 = TREE_OPERAND (op1, 0);
2874   else
2875     con1 = op1;
2876
2877   if (TREE_CODE (con0) == PLUS_EXPR)
2878     {
2879       lit0 = TREE_OPERAND (con0, 1);
2880       con0 = TREE_OPERAND (con0, 0);
2881     }
2882   else
2883     lit0 = integer_zero_node;
2884
2885   if (TREE_CODE (con1) == PLUS_EXPR)
2886     {
2887       lit1 = TREE_OPERAND (con1, 1);
2888       con1 = TREE_OPERAND (con1, 0);
2889     }
2890   else
2891     lit1 = integer_zero_node;
2892
2893   if (operand_equal_p (con0, con1, 0))
2894     {
2895       op0 = lit0;
2896       op1 = lit1;
2897     }
2898
2899
2900   /* First do the subtraction as integers;
2901      then drop through to build the divide operator.
2902      Do not do default conversions on the minus operator
2903      in case restype is a short type.  */
2904
2905   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2906                          convert (restype, op1), 0);
2907   /* This generates an error if op1 is pointer to incomplete type.  */
2908   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2909     error ("arithmetic on pointer to an incomplete type");
2910
2911   /* This generates an error if op0 is pointer to incomplete type.  */
2912   op1 = c_size_in_bytes (target_type);
2913
2914   /* Divide by the size, in easiest possible way.  */
2915   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2916 }
2917 \f
2918 /* Construct and perhaps optimize a tree representation
2919    for a unary operation.  CODE, a tree_code, specifies the operation
2920    and XARG is the operand.
2921    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2922    the default promotions (such as from short to int).
2923    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2924    allows non-lvalues; this is only used to handle conversion of non-lvalue
2925    arrays to pointers in C99.  */
2926
2927 tree
2928 build_unary_op (enum tree_code code, tree xarg, int flag)
2929 {
2930   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2931   tree arg = xarg;
2932   tree argtype = 0;
2933   enum tree_code typecode;
2934   tree val;
2935   int noconvert = flag;
2936   const char *invalid_op_diag;
2937
2938   if (code != ADDR_EXPR)
2939     arg = require_complete_type (arg);
2940
2941   typecode = TREE_CODE (TREE_TYPE (arg));
2942   if (typecode == ERROR_MARK)
2943     return error_mark_node;
2944   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2945     typecode = INTEGER_TYPE;
2946
2947   if ((invalid_op_diag
2948        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2949     {
2950       error (invalid_op_diag);
2951       return error_mark_node;
2952     }
2953
2954   switch (code)
2955     {
2956     case CONVERT_EXPR:
2957       /* This is used for unary plus, because a CONVERT_EXPR
2958          is enough to prevent anybody from looking inside for
2959          associativity, but won't generate any code.  */
2960       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2961             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2962             || typecode == VECTOR_TYPE))
2963         {
2964           error ("wrong type argument to unary plus");
2965           return error_mark_node;
2966         }
2967       else if (!noconvert)
2968         arg = default_conversion (arg);
2969       arg = non_lvalue (arg);
2970       break;
2971
2972     case NEGATE_EXPR:
2973       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2974             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2975             || typecode == VECTOR_TYPE))
2976         {
2977           error ("wrong type argument to unary minus");
2978           return error_mark_node;
2979         }
2980       else if (!noconvert)
2981         arg = default_conversion (arg);
2982       break;
2983
2984     case BIT_NOT_EXPR:
2985       /* ~ works on integer types and non float vectors. */
2986       if (typecode == INTEGER_TYPE
2987           || (typecode == VECTOR_TYPE
2988               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2989         {
2990           if (!noconvert)
2991             arg = default_conversion (arg);
2992         }
2993       else if (typecode == COMPLEX_TYPE)
2994         {
2995           code = CONJ_EXPR;
2996           if (pedantic)
2997             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2998           if (!noconvert)
2999             arg = default_conversion (arg);
3000         }
3001       else
3002         {
3003           error ("wrong type argument to bit-complement");
3004           return error_mark_node;
3005         }
3006       break;
3007
3008     case ABS_EXPR:
3009       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3010         {
3011           error ("wrong type argument to abs");
3012           return error_mark_node;
3013         }
3014       else if (!noconvert)
3015         arg = default_conversion (arg);
3016       break;
3017
3018     case CONJ_EXPR:
3019       /* Conjugating a real value is a no-op, but allow it anyway.  */
3020       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3021             || typecode == COMPLEX_TYPE))
3022         {
3023           error ("wrong type argument to conjugation");
3024           return error_mark_node;
3025         }
3026       else if (!noconvert)
3027         arg = default_conversion (arg);
3028       break;
3029
3030     case TRUTH_NOT_EXPR:
3031       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3032           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3033           && typecode != COMPLEX_TYPE)
3034         {
3035           error ("wrong type argument to unary exclamation mark");
3036           return error_mark_node;
3037         }
3038       arg = c_objc_common_truthvalue_conversion (arg);
3039       return invert_truthvalue (arg);
3040
3041     case REALPART_EXPR:
3042       if (TREE_CODE (arg) == COMPLEX_CST)
3043         return TREE_REALPART (arg);
3044       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3045         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3046       else
3047         return arg;
3048
3049     case IMAGPART_EXPR:
3050       if (TREE_CODE (arg) == COMPLEX_CST)
3051         return TREE_IMAGPART (arg);
3052       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3053         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3054       else
3055         return convert (TREE_TYPE (arg), integer_zero_node);
3056
3057     case PREINCREMENT_EXPR:
3058     case POSTINCREMENT_EXPR:
3059     case PREDECREMENT_EXPR:
3060     case POSTDECREMENT_EXPR:
3061
3062       /* Increment or decrement the real part of the value,
3063          and don't change the imaginary part.  */
3064       if (typecode == COMPLEX_TYPE)
3065         {
3066           tree real, imag;
3067
3068           if (pedantic)
3069             pedwarn ("ISO C does not support %<++%> and %<--%>"
3070                      " on complex types");
3071
3072           arg = stabilize_reference (arg);
3073           real = build_unary_op (REALPART_EXPR, arg, 1);
3074           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3075           real = build_unary_op (code, real, 1);
3076           if (real == error_mark_node || imag == error_mark_node)
3077             return error_mark_node;
3078           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3079                          real, imag);
3080         }
3081
3082       /* Report invalid types.  */
3083
3084       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3085           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3086         {
3087           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3088             error ("wrong type argument to increment");
3089           else
3090             error ("wrong type argument to decrement");
3091
3092           return error_mark_node;
3093         }
3094
3095       {
3096         tree inc;
3097         tree result_type = TREE_TYPE (arg);
3098
3099         arg = get_unwidened (arg, 0);
3100         argtype = TREE_TYPE (arg);
3101
3102         /* Compute the increment.  */
3103
3104         if (typecode == POINTER_TYPE)
3105           {
3106             /* If pointer target is an undefined struct,
3107                we just cannot know how to do the arithmetic.  */
3108             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3109               {
3110                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3111                   error ("increment of pointer to unknown structure");
3112                 else
3113                   error ("decrement of pointer to unknown structure");
3114               }
3115             else if ((pedantic || warn_pointer_arith)
3116                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3117                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
3118               {
3119                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3120                   pedwarn ("wrong type argument to increment");
3121                 else
3122                   pedwarn ("wrong type argument to decrement");
3123               }
3124
3125             inc = c_size_in_bytes (TREE_TYPE (result_type));
3126             inc = fold_convert (sizetype, inc);
3127           }
3128         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3129           {
3130             /* For signed fract types, we invert ++ to -- or
3131                -- to ++, and change inc from 1 to -1, because
3132                it is not possible to represent 1 in signed fract constants.
3133                For unsigned fract types, the result always overflows and
3134                we get an undefined (original) or the maximum value.  */
3135             if (code == PREINCREMENT_EXPR)
3136               code = PREDECREMENT_EXPR;
3137             else if (code == PREDECREMENT_EXPR)
3138               code = PREINCREMENT_EXPR;
3139             else if (code == POSTINCREMENT_EXPR)
3140               code = POSTDECREMENT_EXPR;
3141             else /* code == POSTDECREMENT_EXPR  */
3142               code = POSTINCREMENT_EXPR;
3143
3144             inc = integer_minus_one_node;
3145             inc = convert (argtype, inc);
3146           }
3147         else
3148           {
3149             inc = integer_one_node;
3150             inc = convert (argtype, inc);
3151           }
3152
3153         /* Complain about anything else that is not a true lvalue.  */
3154         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3155                                     || code == POSTINCREMENT_EXPR)
3156                                    ? lv_increment
3157                                    : lv_decrement)))
3158           return error_mark_node;
3159
3160         /* Report a read-only lvalue.  */
3161         if (TREE_READONLY (arg))
3162           {
3163             readonly_error (arg,
3164                             ((code == PREINCREMENT_EXPR
3165                               || code == POSTINCREMENT_EXPR)
3166                              ? lv_increment : lv_decrement));
3167             return error_mark_node;
3168           }
3169
3170         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3171           val = boolean_increment (code, arg);
3172         else
3173           val = build2 (code, TREE_TYPE (arg), arg, inc);
3174         TREE_SIDE_EFFECTS (val) = 1;
3175         val = convert (result_type, val);
3176         if (TREE_CODE (val) != code)
3177           TREE_NO_WARNING (val) = 1;
3178         return val;
3179       }
3180
3181     case ADDR_EXPR:
3182       /* Note that this operation never does default_conversion.  */
3183
3184       /* Let &* cancel out to simplify resulting code.  */
3185       if (TREE_CODE (arg) == INDIRECT_REF)
3186         {
3187           /* Don't let this be an lvalue.  */
3188           if (lvalue_p (TREE_OPERAND (arg, 0)))
3189             return non_lvalue (TREE_OPERAND (arg, 0));
3190           return TREE_OPERAND (arg, 0);
3191         }
3192
3193       /* For &x[y], return x+y */
3194       if (TREE_CODE (arg) == ARRAY_REF)
3195         {
3196           tree op0 = TREE_OPERAND (arg, 0);
3197           if (!c_mark_addressable (op0))
3198             return error_mark_node;
3199           return build_binary_op (PLUS_EXPR,
3200                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3201                                    ? array_to_pointer_conversion (op0)
3202                                    : op0),
3203                                   TREE_OPERAND (arg, 1), 1);
3204         }
3205
3206       /* Anything not already handled and not a true memory reference
3207          or a non-lvalue array is an error.  */
3208       else if (typecode != FUNCTION_TYPE && !flag
3209                && !lvalue_or_else (arg, lv_addressof))
3210         return error_mark_node;
3211
3212       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3213       argtype = TREE_TYPE (arg);
3214
3215       /* If the lvalue is const or volatile, merge that into the type
3216          to which the address will point.  Note that you can't get a
3217          restricted pointer by taking the address of something, so we
3218          only have to deal with `const' and `volatile' here.  */
3219       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3220           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3221           argtype = c_build_type_variant (argtype,
3222                                           TREE_READONLY (arg),
3223                                           TREE_THIS_VOLATILE (arg));
3224
3225       if (!c_mark_addressable (arg))
3226         return error_mark_node;
3227
3228       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3229                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3230
3231       argtype = build_pointer_type (argtype);
3232
3233       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3234          when we have proper support for integer constant expressions.  */
3235       val = get_base_address (arg);
3236       if (val && TREE_CODE (val) == INDIRECT_REF
3237           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3238         {
3239           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3240
3241           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3242           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3243         }
3244
3245       val = build1 (ADDR_EXPR, argtype, arg);
3246
3247       return val;
3248
3249     default:
3250       gcc_unreachable ();
3251     }
3252
3253   if (argtype == 0)
3254     argtype = TREE_TYPE (arg);
3255   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3256                                 : fold_build1 (code, argtype, arg);
3257 }
3258
3259 /* Return nonzero if REF is an lvalue valid for this language.
3260    Lvalues can be assigned, unless their type has TYPE_READONLY.
3261    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3262
3263 static int
3264 lvalue_p (const_tree ref)
3265 {
3266   const enum tree_code code = TREE_CODE (ref);
3267
3268   switch (code)
3269     {
3270     case REALPART_EXPR:
3271     case IMAGPART_EXPR:
3272     case COMPONENT_REF:
3273       return lvalue_p (TREE_OPERAND (ref, 0));
3274
3275     case COMPOUND_LITERAL_EXPR:
3276     case STRING_CST:
3277       return 1;
3278
3279     case INDIRECT_REF:
3280     case ARRAY_REF:
3281     case VAR_DECL:
3282     case PARM_DECL:
3283     case RESULT_DECL:
3284     case ERROR_MARK:
3285       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3286               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3287
3288     case BIND_EXPR:
3289       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3290
3291     default:
3292       return 0;
3293     }
3294 }
3295 \f
3296 /* Give an error for storing in something that is 'const'.  */
3297
3298 static void
3299 readonly_error (tree arg, enum lvalue_use use)
3300 {
3301   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3302               || use == lv_asm);
3303   /* Using this macro rather than (for example) arrays of messages
3304      ensures that all the format strings are checked at compile
3305      time.  */
3306 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3307                                    : (use == lv_increment ? (I)         \
3308                                    : (use == lv_decrement ? (D) : (AS))))
3309   if (TREE_CODE (arg) == COMPONENT_REF)
3310     {
3311       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3312         readonly_error (TREE_OPERAND (arg, 0), use);
3313       else
3314         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3315                              G_("increment of read-only member %qD"),
3316                              G_("decrement of read-only member %qD"),
3317                              G_("read-only member %qD used as %<asm%> output")),
3318                TREE_OPERAND (arg, 1));
3319     }
3320   else if (TREE_CODE (arg) == VAR_DECL)
3321     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3322                          G_("increment of read-only variable %qD"),
3323                          G_("decrement of read-only variable %qD"),
3324                          G_("read-only variable %qD used as %<asm%> output")),
3325            arg);
3326   else
3327     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3328                          G_("increment of read-only location %qE"),
3329                          G_("decrement of read-only location %qE"),
3330                          G_("read-only location %qE used as %<asm%> output")),
3331            arg);
3332 }
3333
3334
3335 /* Return nonzero if REF is an lvalue valid for this language;
3336    otherwise, print an error message and return zero.  USE says
3337    how the lvalue is being used and so selects the error message.  */
3338
3339 static int
3340 lvalue_or_else (const_tree ref, enum lvalue_use use)
3341 {
3342   int win = lvalue_p (ref);
3343
3344   if (!win)
3345     lvalue_error (use);
3346
3347   return win;
3348 }
3349 \f
3350 /* Mark EXP saying that we need to be able to take the
3351    address of it; it should not be allocated in a register.
3352    Returns true if successful.  */
3353
3354 bool
3355 c_mark_addressable (tree exp)
3356 {
3357   tree x = exp;
3358
3359   while (1)
3360     switch (TREE_CODE (x))
3361       {
3362       case COMPONENT_REF:
3363         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3364           {
3365             error
3366               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3367             return false;
3368           }
3369
3370         /* ... fall through ...  */
3371
3372       case ADDR_EXPR:
3373       case ARRAY_REF:
3374       case REALPART_EXPR:
3375       case IMAGPART_EXPR:
3376         x = TREE_OPERAND (x, 0);
3377         break;
3378
3379       case COMPOUND_LITERAL_EXPR:
3380       case CONSTRUCTOR:
3381         TREE_ADDRESSABLE (x) = 1;
3382         return true;
3383
3384       case VAR_DECL:
3385       case CONST_DECL:
3386       case PARM_DECL:
3387       case RESULT_DECL:
3388         if (C_DECL_REGISTER (x)
3389             && DECL_NONLOCAL (x))
3390           {
3391             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3392               {
3393                 error
3394                   ("global register variable %qD used in nested function", x);
3395                 return false;
3396               }
3397             pedwarn ("register variable %qD used in nested function", x);
3398           }
3399         else if (C_DECL_REGISTER (x))
3400           {
3401             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3402               error ("address of global register variable %qD requested", x);
3403             else
3404               error ("address of register variable %qD requested", x);
3405             return false;
3406           }
3407
3408         /* drops in */
3409       case FUNCTION_DECL:
3410         TREE_ADDRESSABLE (x) = 1;
3411         /* drops out */
3412       default:
3413         return true;
3414     }
3415 }
3416 \f
3417 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3418
3419 tree
3420 build_conditional_expr (tree ifexp, tree op1, tree op2)
3421 {
3422   tree type1;
3423   tree type2;
3424   enum tree_code code1;
3425   enum tree_code code2;
3426   tree result_type = NULL;
3427   tree orig_op1 = op1, orig_op2 = op2;
3428   bool objc_ok;
3429
3430   /* Promote both alternatives.  */
3431
3432   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3433     op1 = default_conversion (op1);
3434   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3435     op2 = default_conversion (op2);
3436
3437   if (TREE_CODE (ifexp) == ERROR_MARK
3438       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3439       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3440     return error_mark_node;
3441
3442   type1 = TREE_TYPE (op1);
3443   code1 = TREE_CODE (type1);
3444   type2 = TREE_TYPE (op2);
3445   code2 = TREE_CODE (type2);
3446
3447   /* C90 does not permit non-lvalue arrays in conditional expressions.
3448      In C99 they will be pointers by now.  */
3449   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3450     {
3451       error ("non-lvalue array in conditional expression");
3452       return error_mark_node;
3453     }
3454
3455   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3456
3457   /* Quickly detect the usual case where op1 and op2 have the same type
3458      after promotion.  */
3459   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3460     {
3461       if (type1 == type2)
3462         result_type = type1;
3463       else
3464         result_type = TYPE_MAIN_VARIANT (type1);
3465     }
3466   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3467             || code1 == COMPLEX_TYPE)
3468            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3469                || code2 == COMPLEX_TYPE))
3470     {
3471       result_type = c_common_type (type1, type2);
3472
3473       /* If -Wsign-compare, warn here if type1 and type2 have
3474          different signedness.  We'll promote the signed to unsigned
3475          and later code won't know it used to be different.
3476          Do this check on the original types, so that explicit casts
3477          will be considered, but default promotions won't.  */
3478       if (warn_sign_compare && !skip_evaluation)
3479         {
3480           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3481           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3482
3483           if (unsigned_op1 ^ unsigned_op2)
3484             {
3485               bool ovf;
3486
3487               /* Do not warn if the result type is signed, since the
3488                  signed type will only be chosen if it can represent
3489                  all the values of the unsigned type.  */
3490               if (!TYPE_UNSIGNED (result_type))
3491                 /* OK */;
3492               /* Do not warn if the signed quantity is an unsuffixed
3493                  integer literal (or some static constant expression
3494                  involving such literals) and it is non-negative.  */
3495               else if ((unsigned_op2
3496                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3497                        || (unsigned_op1
3498                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3499                 /* OK */;
3500               else
3501                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3502             }
3503         }
3504     }
3505   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3506     {
3507       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3508         pedwarn ("ISO C forbids conditional expr with only one void side");
3509       result_type = void_type_node;
3510     }
3511   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3512     {
3513       if (comp_target_types (type1, type2))
3514         result_type = common_pointer_type (type1, type2);
3515       else if (null_pointer_constant_p (orig_op1))
3516         result_type = qualify_type (type2, type1);
3517       else if (null_pointer_constant_p (orig_op2))
3518         result_type = qualify_type (type1, type2);
3519       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3520         {
3521           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3522             pedwarn ("ISO C forbids conditional expr between "
3523                      "%<void *%> and function pointer");
3524           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3525                                                           TREE_TYPE (type2)));
3526         }
3527       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3528         {
3529           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3530             pedwarn ("ISO C forbids conditional expr between "
3531                      "%<void *%> and function pointer");
3532           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3533                                                           TREE_TYPE (type1)));
3534         }
3535       else
3536         {
3537           if (!objc_ok)
3538             pedwarn ("pointer type mismatch in conditional expression");
3539           result_type = build_pointer_type (void_type_node);
3540         }
3541     }
3542   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3543     {
3544       if (!null_pointer_constant_p (orig_op2))
3545         pedwarn ("pointer/integer type mismatch in conditional expression");
3546       else
3547         {
3548           op2 = null_pointer_node;
3549         }
3550       result_type = type1;
3551     }
3552   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3553     {
3554       if (!null_pointer_constant_p (orig_op1))
3555         pedwarn ("pointer/integer type mismatch in conditional expression");
3556       else
3557         {
3558           op1 = null_pointer_node;
3559         }
3560       result_type = type2;
3561     }
3562
3563   if (!result_type)
3564     {
3565       if (flag_cond_mismatch)
3566         result_type = void_type_node;
3567       else
3568         {
3569           error ("type mismatch in conditional expression");
3570           return error_mark_node;
3571         }
3572     }
3573
3574   /* Merge const and volatile flags of the incoming types.  */
3575   result_type
3576     = build_type_variant (result_type,
3577                           TREE_READONLY (op1) || TREE_READONLY (op2),
3578                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3579
3580   if (result_type != TREE_TYPE (op1))
3581     op1 = convert_and_check (result_type, op1);
3582   if (result_type != TREE_TYPE (op2))
3583     op2 = convert_and_check (result_type, op2);
3584
3585   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3586 }
3587 \f
3588 /* Return a compound expression that performs two expressions and
3589    returns the value of the second of them.  */
3590
3591 tree
3592 build_compound_expr (tree expr1, tree expr2)
3593 {
3594   if (!TREE_SIDE_EFFECTS (expr1))
3595     {
3596       /* The left-hand operand of a comma expression is like an expression
3597          statement: with -Wunused, we should warn if it doesn't have
3598          any side-effects, unless it was explicitly cast to (void).  */
3599       if (warn_unused_value)
3600         {
3601           if (VOID_TYPE_P (TREE_TYPE (expr1))
3602               && (TREE_CODE (expr1) == NOP_EXPR
3603                   || TREE_CODE (expr1) == CONVERT_EXPR))
3604             ; /* (void) a, b */
3605           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3606                    && TREE_CODE (expr1) == COMPOUND_EXPR
3607                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3608                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3609             ; /* (void) a, (void) b, c */
3610           else
3611             warning (OPT_Wunused_value,
3612                      "left-hand operand of comma expression has no effect");
3613         }
3614     }
3615
3616   /* With -Wunused, we should also warn if the left-hand operand does have
3617      side-effects, but computes a value which is not used.  For example, in
3618      `foo() + bar(), baz()' the result of the `+' operator is not used,
3619      so we should issue a warning.  */
3620   else if (warn_unused_value)
3621     warn_if_unused_value (expr1, input_location);
3622
3623   if (expr2 == error_mark_node)
3624     return error_mark_node;
3625
3626   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3627 }
3628
3629 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3630
3631 tree
3632 build_c_cast (tree type, tree expr)
3633 {
3634   tree value = expr;
3635
3636   if (type == error_mark_node || expr == error_mark_node)
3637     return error_mark_node;
3638
3639   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3640      only in <protocol> qualifications.  But when constructing cast expressions,
3641      the protocols do matter and must be kept around.  */
3642   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3643     return build1 (NOP_EXPR, type, expr);
3644
3645   type = TYPE_MAIN_VARIANT (type);
3646
3647   if (TREE_CODE (type) == ARRAY_TYPE)
3648     {
3649       error ("cast specifies array type");
3650       return error_mark_node;
3651     }
3652
3653   if (TREE_CODE (type) == FUNCTION_TYPE)
3654     {
3655       error ("cast specifies function type");
3656       return error_mark_node;
3657     }
3658
3659   if (!VOID_TYPE_P (type))
3660     {
3661       value = require_complete_type (value);
3662       if (value == error_mark_node)
3663         return error_mark_node;
3664     }
3665
3666   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3667     {
3668       if (pedantic)
3669         {
3670           if (TREE_CODE (type) == RECORD_TYPE
3671               || TREE_CODE (type) == UNION_TYPE)
3672             pedwarn ("ISO C forbids casting nonscalar to the same type");
3673         }
3674     }
3675   else if (TREE_CODE (type) == UNION_TYPE)
3676     {
3677       tree field;
3678
3679       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3680         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3681                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3682           break;
3683
3684       if (field)
3685         {
3686           tree t;
3687
3688           if (pedantic)
3689             pedwarn ("ISO C forbids casts to union type");
3690           t = digest_init (type,
3691                            build_constructor_single (type, field, value),
3692                            true, 0);
3693           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3694           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3695           return t;
3696         }
3697       error ("cast to union type from type not present in union");
3698       return error_mark_node;
3699     }
3700   else
3701     {
3702       tree otype, ovalue;
3703
3704       if (type == void_type_node)
3705         return build1 (CONVERT_EXPR, type, value);
3706
3707       otype = TREE_TYPE (value);
3708
3709       /* Optionally warn about potentially worrisome casts.  */
3710
3711       if (warn_cast_qual
3712           && TREE_CODE (type) == POINTER_TYPE
3713           && TREE_CODE (otype) == POINTER_TYPE)
3714         {
3715           tree in_type = type;
3716           tree in_otype = otype;
3717           int added = 0;
3718           int discarded = 0;
3719
3720           /* Check that the qualifiers on IN_TYPE are a superset of
3721              the qualifiers of IN_OTYPE.  The outermost level of
3722              POINTER_TYPE nodes is uninteresting and we stop as soon
3723              as we hit a non-POINTER_TYPE node on either type.  */
3724           do
3725             {
3726               in_otype = TREE_TYPE (in_otype);
3727               in_type = TREE_TYPE (in_type);
3728
3729               /* GNU C allows cv-qualified function types.  'const'
3730                  means the function is very pure, 'volatile' means it
3731                  can't return.  We need to warn when such qualifiers
3732                  are added, not when they're taken away.  */
3733               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3734                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3735                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3736               else
3737                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3738             }
3739           while (TREE_CODE (in_type) == POINTER_TYPE
3740                  && TREE_CODE (in_otype) == POINTER_TYPE);
3741
3742           if (added)
3743             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3744
3745           if (discarded)
3746             /* There are qualifiers present in IN_OTYPE that are not
3747                present in IN_TYPE.  */
3748             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3749         }
3750
3751       /* Warn about possible alignment problems.  */
3752       if (STRICT_ALIGNMENT
3753           && TREE_CODE (type) == POINTER_TYPE
3754           && TREE_CODE (otype) == POINTER_TYPE
3755           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3756           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3757           /* Don't warn about opaque types, where the actual alignment
3758              restriction is unknown.  */
3759           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3760                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3761                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3762           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3763         warning (OPT_Wcast_align,
3764                  "cast increases required alignment of target type");
3765
3766       if (TREE_CODE (type) == INTEGER_TYPE
3767           && TREE_CODE (otype) == POINTER_TYPE
3768           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3769       /* Unlike conversion of integers to pointers, where the
3770          warning is disabled for converting constants because
3771          of cases such as SIG_*, warn about converting constant
3772          pointers to integers. In some cases it may cause unwanted
3773          sign extension, and a warning is appropriate.  */
3774         warning (OPT_Wpointer_to_int_cast,
3775                  "cast from pointer to integer of different size");
3776
3777       if (TREE_CODE (value) == CALL_EXPR
3778           && TREE_CODE (type) != TREE_CODE (otype))
3779         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3780                  "to non-matching type %qT", otype, type);
3781
3782       if (TREE_CODE (type) == POINTER_TYPE
3783           && TREE_CODE (otype) == INTEGER_TYPE
3784           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3785           /* Don't warn about converting any constant.  */
3786           && !TREE_CONSTANT (value))
3787         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3788                  "of different size");
3789
3790       if (warn_strict_aliasing <= 2)
3791         strict_aliasing_warning (otype, type, expr);
3792
3793       /* If pedantic, warn for conversions between function and object
3794          pointer types, except for converting a null pointer constant
3795          to function pointer type.  */
3796       if (pedantic
3797           && TREE_CODE (type) == POINTER_TYPE
3798           && TREE_CODE (otype) == POINTER_TYPE
3799           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3800           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3801         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3802
3803       if (pedantic
3804           && TREE_CODE (type) == POINTER_TYPE
3805           && TREE_CODE (otype) == POINTER_TYPE
3806           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3807           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3808           && !null_pointer_constant_p (value))
3809         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3810
3811       ovalue = value;
3812       value = convert (type, value);
3813
3814       /* Ignore any integer overflow caused by the cast.  */
3815       if (TREE_CODE (value) == INTEGER_CST)
3816         {
3817           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3818             {
3819               if (!TREE_OVERFLOW (value))
3820                 {
3821                   /* Avoid clobbering a shared constant.  */
3822                   value = copy_node (value);
3823                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3824                 }
3825             }
3826           else if (TREE_OVERFLOW (value))
3827             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3828             value = build_int_cst_wide (TREE_TYPE (value),
3829                                         TREE_INT_CST_LOW (value),
3830                                         TREE_INT_CST_HIGH (value));
3831         }
3832     }
3833
3834   /* Don't let a cast be an lvalue.  */
3835   if (value == expr)
3836     value = non_lvalue (value);
3837
3838   return value;
3839 }
3840
3841 /* Interpret a cast of expression EXPR to type TYPE.  */
3842 tree
3843 c_cast_expr (struct c_type_name *type_name, tree expr)
3844 {
3845   tree type;
3846   int saved_wsp = warn_strict_prototypes;
3847
3848   /* This avoids warnings about unprototyped casts on
3849      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3850   if (TREE_CODE (expr) == INTEGER_CST)
3851     warn_strict_prototypes = 0;
3852   type = groktypename (type_name);
3853   warn_strict_prototypes = saved_wsp;
3854
3855   return build_c_cast (type, expr);
3856 }
3857 \f
3858 /* Build an assignment expression of lvalue LHS from value RHS.
3859    MODIFYCODE is the code for a binary operator that we use
3860    to combine the old value of LHS with RHS to get the new value.
3861    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3862
3863 tree
3864 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3865 {
3866   tree result;
3867   tree newrhs;
3868   tree lhstype = TREE_TYPE (lhs);
3869   tree olhstype = lhstype;
3870
3871   /* Types that aren't fully specified cannot be used in assignments.  */
3872   lhs = require_complete_type (lhs);
3873
3874   /* Avoid duplicate error messages from operands that had errors.  */
3875   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3876     return error_mark_node;
3877
3878   if (!lvalue_or_else (lhs, lv_assign))
3879     return error_mark_node;
3880
3881   STRIP_TYPE_NOPS (rhs);
3882
3883   newrhs = rhs;
3884
3885   /* If a binary op has been requested, combine the old LHS value with the RHS
3886      producing the value we should actually store into the LHS.  */
3887
3888   if (modifycode != NOP_EXPR)
3889     {
3890       lhs = stabilize_reference (lhs);
3891       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3892     }
3893
3894   /* Give an error for storing in something that is 'const'.  */
3895
3896   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3897       || ((TREE_CODE (lhstype) == RECORD_TYPE
3898            || TREE_CODE (lhstype) == UNION_TYPE)
3899           && C_TYPE_FIELDS_READONLY (lhstype)))
3900     {
3901       readonly_error (lhs, lv_assign);
3902       return error_mark_node;
3903     }
3904
3905   /* If storing into a structure or union member,
3906      it has probably been given type `int'.
3907      Compute the type that would go with
3908      the actual amount of storage the member occupies.  */
3909
3910   if (TREE_CODE (lhs) == COMPONENT_REF
3911       && (TREE_CODE (lhstype) == INTEGER_TYPE
3912           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3913           || TREE_CODE (lhstype) == REAL_TYPE
3914           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3915     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3916
3917   /* If storing in a field that is in actuality a short or narrower than one,
3918      we must store in the field in its actual type.  */
3919
3920   if (lhstype != TREE_TYPE (lhs))
3921     {
3922       lhs = copy_node (lhs);
3923       TREE_TYPE (lhs) = lhstype;
3924     }
3925
3926   /* Convert new value to destination type.  */
3927
3928   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3929                                    NULL_TREE, NULL_TREE, 0);
3930   if (TREE_CODE (newrhs) == ERROR_MARK)
3931     return error_mark_node;
3932
3933   /* Emit ObjC write barrier, if necessary.  */
3934   if (c_dialect_objc () && flag_objc_gc)
3935     {
3936       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3937       if (result)
3938         return result;
3939     }
3940
3941   /* Scan operands.  */
3942
3943   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3944   TREE_SIDE_EFFECTS (result) = 1;
3945
3946   /* If we got the LHS in a different type for storing in,
3947      convert the result back to the nominal type of LHS
3948      so that the value we return always has the same type
3949      as the LHS argument.  */
3950
3951   if (olhstype == TREE_TYPE (result))
3952     return result;
3953   return convert_for_assignment (olhstype, result, ic_assign,
3954                                  NULL_TREE, NULL_TREE, 0);
3955 }
3956 \f
3957 /* Convert value RHS to type TYPE as preparation for an assignment
3958    to an lvalue of type TYPE.
3959    The real work of conversion is done by `convert'.
3960    The purpose of this function is to generate error messages
3961    for assignments that are not allowed in C.
3962    ERRTYPE says whether it is argument passing, assignment,
3963    initialization or return.
3964
3965    FUNCTION is a tree for the function being called.
3966    PARMNUM is the number of the argument, for printing in error messages.  */
3967
3968 static tree
3969 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3970                         tree fundecl, tree function, int parmnum)
3971 {
3972   enum tree_code codel = TREE_CODE (type);
3973   tree rhstype;
3974   enum tree_code coder;
3975   tree rname = NULL_TREE;
3976   bool objc_ok = false;
3977
3978   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3979     {
3980       tree selector;
3981       /* Change pointer to function to the function itself for
3982          diagnostics.  */
3983       if (TREE_CODE (function) == ADDR_EXPR
3984           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3985         function = TREE_OPERAND (function, 0);
3986
3987       /* Handle an ObjC selector specially for diagnostics.  */
3988       selector = objc_message_selector ();
3989       rname = function;
3990       if (selector && parmnum > 2)
3991         {
3992           rname = selector;
3993           parmnum -= 2;
3994         }
3995     }
3996
3997   /* This macro is used to emit diagnostics to ensure that all format
3998      strings are complete sentences, visible to gettext and checked at
3999      compile time.  */
4000 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
4001   do {                                          \
4002     switch (errtype)                            \
4003       {                                         \
4004       case ic_argpass:                          \
4005         pedwarn (AR, parmnum, rname);           \
4006         break;                                  \
4007       case ic_argpass_nonproto:                 \
4008         warning (0, AR, parmnum, rname);                \
4009         break;                                  \
4010       case ic_assign:                           \
4011         pedwarn (AS);                           \
4012         break;                                  \
4013       case ic_init:                             \
4014         pedwarn (IN);                           \
4015         break;                                  \
4016       case ic_return:                           \
4017         pedwarn (RE);                           \
4018         break;                                  \
4019       default:                                  \
4020         gcc_unreachable ();                     \
4021       }                                         \
4022   } while (0)
4023
4024   STRIP_TYPE_NOPS (rhs);
4025
4026   if (optimize && TREE_CODE (rhs) == VAR_DECL
4027            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
4028     rhs = decl_constant_value_for_broken_optimization (rhs);
4029
4030   rhstype = TREE_TYPE (rhs);
4031   coder = TREE_CODE (rhstype);
4032
4033   if (coder == ERROR_MARK)
4034     return error_mark_node;
4035
4036   if (c_dialect_objc ())
4037     {
4038       int parmno;
4039
4040       switch (errtype)
4041         {
4042         case ic_return:
4043           parmno = 0;
4044           break;
4045
4046         case ic_assign:
4047           parmno = -1;
4048           break;
4049
4050         case ic_init:
4051           parmno = -2;
4052           break;
4053
4054         default:
4055           parmno = parmnum;
4056           break;
4057         }
4058
4059       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4060     }
4061
4062   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4063     return rhs;
4064
4065   if (coder == VOID_TYPE)
4066     {
4067       /* Except for passing an argument to an unprototyped function,
4068          this is a constraint violation.  When passing an argument to
4069          an unprototyped function, it is compile-time undefined;
4070          making it a constraint in that case was rejected in
4071          DR#252.  */
4072       error ("void value not ignored as it ought to be");
4073       return error_mark_node;
4074     }
4075   rhs = require_complete_type (rhs);
4076   if (rhs == error_mark_node)
4077     return error_mark_node;
4078   /* A type converts to a reference to it.
4079      This code doesn't fully support references, it's just for the
4080      special case of va_start and va_copy.  */
4081   if (codel == REFERENCE_TYPE
4082       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4083     {
4084       if (!lvalue_p (rhs))
4085         {
4086           error ("cannot pass rvalue to reference parameter");
4087           return error_mark_node;
4088         }
4089       if (!c_mark_addressable (rhs))
4090         return error_mark_node;
4091       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4092
4093       /* We already know that these two types are compatible, but they
4094          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4095          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4096          likely to be va_list, a typedef to __builtin_va_list, which
4097          is different enough that it will cause problems later.  */
4098       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4099         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4100
4101       rhs = build1 (NOP_EXPR, type, rhs);
4102       return rhs;
4103     }
4104   /* Some types can interconvert without explicit casts.  */
4105   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4106            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4107     return convert (type, rhs);
4108   /* Arithmetic types all interconvert, and enum is treated like int.  */
4109   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4110             || codel == FIXED_POINT_TYPE
4111             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4112             || codel == BOOLEAN_TYPE)
4113            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4114                || coder == FIXED_POINT_TYPE
4115                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4116                || coder == BOOLEAN_TYPE))
4117     return convert_and_check (type, rhs);
4118
4119   /* Aggregates in different TUs might need conversion.  */
4120   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4121       && codel == coder
4122       && comptypes (type, rhstype))
4123     return convert_and_check (type, rhs);
4124
4125   /* Conversion to a transparent union from its member types.
4126      This applies only to function arguments.  */
4127   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4128       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4129     {
4130       tree memb, marginal_memb = NULL_TREE;
4131
4132       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4133         {
4134           tree memb_type = TREE_TYPE (memb);
4135
4136           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4137                          TYPE_MAIN_VARIANT (rhstype)))
4138             break;
4139
4140           if (TREE_CODE (memb_type) != POINTER_TYPE)
4141             continue;
4142
4143           if (coder == POINTER_TYPE)
4144             {
4145               tree ttl = TREE_TYPE (memb_type);
4146               tree ttr = TREE_TYPE (rhstype);
4147
4148               /* Any non-function converts to a [const][volatile] void *
4149                  and vice versa; otherwise, targets must be the same.
4150                  Meanwhile, the lhs target must have all the qualifiers of
4151                  the rhs.  */
4152               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4153                   || comp_target_types (memb_type, rhstype))
4154                 {
4155                   /* If this type won't generate any warnings, use it.  */
4156                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4157                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4158                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4159                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4160                              == TYPE_QUALS (ttr))
4161                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4162                              == TYPE_QUALS (ttl))))
4163                     break;
4164
4165                   /* Keep looking for a better type, but remember this one.  */
4166                   if (!marginal_memb)
4167                     marginal_memb = memb;
4168                 }
4169             }
4170
4171           /* Can convert integer zero to any pointer type.  */
4172           if (null_pointer_constant_p (rhs))
4173             {
4174               rhs = null_pointer_node;
4175               break;
4176             }
4177         }
4178
4179       if (memb || marginal_memb)
4180         {
4181           if (!memb)
4182             {
4183               /* We have only a marginally acceptable member type;
4184                  it needs a warning.  */
4185               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4186               tree ttr = TREE_TYPE (rhstype);
4187
4188               /* Const and volatile mean something different for function
4189                  types, so the usual warnings are not appropriate.  */
4190               if (TREE_CODE (ttr) == FUNCTION_TYPE
4191                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4192                 {
4193                   /* Because const and volatile on functions are
4194                      restrictions that say the function will not do
4195                      certain things, it is okay to use a const or volatile
4196                      function where an ordinary one is wanted, but not
4197                      vice-versa.  */
4198                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4199                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4200                                             "makes qualified function "
4201                                             "pointer from unqualified"),
4202                                          G_("assignment makes qualified "
4203                                             "function pointer from "
4204                                             "unqualified"),
4205                                          G_("initialization makes qualified "
4206                                             "function pointer from "
4207                                             "unqualified"),
4208                                          G_("return makes qualified function "
4209                                             "pointer from unqualified"));
4210                 }
4211               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4212                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4213                                         "qualifiers from pointer target type"),
4214                                      G_("assignment discards qualifiers "
4215                                         "from pointer target type"),
4216                                      G_("initialization discards qualifiers "
4217                                         "from pointer target type"),
4218                                      G_("return discards qualifiers from "
4219                                         "pointer target type"));
4220
4221               memb = marginal_memb;
4222             }
4223
4224           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4225             pedwarn ("ISO C prohibits argument conversion to union type");
4226
4227           rhs = fold_convert (TREE_TYPE (memb), rhs);
4228           return build_constructor_single (type, memb, rhs);
4229         }
4230     }
4231
4232   /* Conversions among pointers */
4233   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4234            && (coder == codel))
4235     {
4236       tree ttl = TREE_TYPE (type);
4237       tree ttr = TREE_TYPE (rhstype);
4238       tree mvl = ttl;
4239       tree mvr = ttr;
4240       bool is_opaque_pointer;
4241       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4242
4243       if (TREE_CODE (mvl) != ARRAY_TYPE)
4244         mvl = TYPE_MAIN_VARIANT (mvl);
4245       if (TREE_CODE (mvr) != ARRAY_TYPE)
4246         mvr = TYPE_MAIN_VARIANT (mvr);
4247       /* Opaque pointers are treated like void pointers.  */
4248       is_opaque_pointer = (targetm.vector_opaque_p (type)
4249                            || targetm.vector_opaque_p (rhstype))
4250         && TREE_CODE (ttl) == VECTOR_TYPE
4251         && TREE_CODE (ttr) == VECTOR_TYPE;
4252
4253       /* C++ does not allow the implicit conversion void* -> T*.  However,
4254          for the purpose of reducing the number of false positives, we
4255          tolerate the special case of
4256
4257                 int *p = NULL;
4258
4259          where NULL is typically defined in C to be '(void *) 0'.  */
4260       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4261         warning (OPT_Wc___compat, "request for implicit conversion from "
4262                  "%qT to %qT not permitted in C++", rhstype, type);
4263
4264       /* Check if the right-hand side has a format attribute but the
4265          left-hand side doesn't.  */
4266       if (warn_missing_format_attribute
4267           && check_missing_format_attribute (type, rhstype))
4268         {
4269           switch (errtype)
4270           {
4271           case ic_argpass:
4272           case ic_argpass_nonproto:
4273             warning (OPT_Wmissing_format_attribute,
4274                      "argument %d of %qE might be "
4275                      "a candidate for a format attribute",
4276                      parmnum, rname);
4277             break;
4278           case ic_assign:
4279             warning (OPT_Wmissing_format_attribute,
4280                      "assignment left-hand side might be "
4281                      "a candidate for a format attribute");
4282             break;
4283           case ic_init:
4284             warning (OPT_Wmissing_format_attribute,
4285                      "initialization left-hand side might be "
4286                      "a candidate for a format attribute");
4287             break;
4288           case ic_return:
4289             warning (OPT_Wmissing_format_attribute,
4290                      "return type might be "
4291                      "a candidate for a format attribute");
4292             break;
4293           default:
4294             gcc_unreachable ();
4295           }
4296         }
4297
4298       /* Any non-function converts to a [const][volatile] void *
4299          and vice versa; otherwise, targets must be the same.
4300          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4301       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4302           || (target_cmp = comp_target_types (type, rhstype))
4303           || is_opaque_pointer
4304           || (c_common_unsigned_type (mvl)
4305               == c_common_unsigned_type (mvr)))
4306         {
4307           if (pedantic
4308               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4309                   ||
4310                   (VOID_TYPE_P (ttr)
4311                    && !null_pointer_constant_p (rhs)
4312                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4313             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4314                                     "%qE between function pointer "
4315                                     "and %<void *%>"),
4316                                  G_("ISO C forbids assignment between "
4317                                     "function pointer and %<void *%>"),
4318                                  G_("ISO C forbids initialization between "
4319                                     "function pointer and %<void *%>"),
4320                                  G_("ISO C forbids return between function "
4321                                     "pointer and %<void *%>"));
4322           /* Const and volatile mean something different for function types,
4323              so the usual warnings are not appropriate.  */
4324           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4325                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4326             {
4327               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4328                 {
4329                   /* Types differing only by the presence of the 'volatile'
4330                      qualifier are acceptable if the 'volatile' has been added
4331                      in by the Objective-C EH machinery.  */
4332                   if (!objc_type_quals_match (ttl, ttr))
4333                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4334                                             "qualifiers from pointer target type"),
4335                                          G_("assignment discards qualifiers "
4336                                             "from pointer target type"),
4337                                          G_("initialization discards qualifiers "
4338                                             "from pointer target type"),
4339                                          G_("return discards qualifiers from "
4340                                             "pointer target type"));
4341                 }
4342               /* If this is not a case of ignoring a mismatch in signedness,
4343                  no warning.  */
4344               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4345                        || target_cmp)
4346                 ;
4347               /* If there is a mismatch, do warn.  */
4348               else if (warn_pointer_sign)
4349                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4350                                         "%d of %qE differ in signedness"),
4351                                      G_("pointer targets in assignment "
4352                                         "differ in signedness"),
4353                                      G_("pointer targets in initialization "
4354                                         "differ in signedness"),
4355                                      G_("pointer targets in return differ "
4356                                         "in signedness"));
4357             }
4358           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4359                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4360             {
4361               /* Because const and volatile on functions are restrictions
4362                  that say the function will not do certain things,
4363                  it is okay to use a const or volatile function
4364                  where an ordinary one is wanted, but not vice-versa.  */
4365               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4366                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4367                                         "qualified function pointer "
4368                                         "from unqualified"),
4369                                      G_("assignment makes qualified function "
4370                                         "pointer from unqualified"),
4371                                      G_("initialization makes qualified "
4372                                         "function pointer from unqualified"),
4373                                      G_("return makes qualified function "
4374                                         "pointer from unqualified"));
4375             }
4376         }
4377       else
4378         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4379         if (!objc_ok)
4380           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4381                                   "incompatible pointer type"),
4382                                G_("assignment from incompatible pointer type"),
4383                                G_("initialization from incompatible "
4384                                   "pointer type"),
4385                                G_("return from incompatible pointer type"));
4386
4387       return convert (type, rhs);
4388     }
4389   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4390     {
4391       /* ??? This should not be an error when inlining calls to
4392          unprototyped functions.  */
4393       error ("invalid use of non-lvalue array");
4394       return error_mark_node;
4395     }
4396   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4397     {
4398       /* An explicit constant 0 can convert to a pointer,
4399          or one that results from arithmetic, even including
4400          a cast to integer type.  */
4401       if (!null_pointer_constant_p (rhs))
4402         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4403                                 "pointer from integer without a cast"),
4404                              G_("assignment makes pointer from integer "
4405                                 "without a cast"),
4406                              G_("initialization makes pointer from "
4407                                 "integer without a cast"),
4408                              G_("return makes pointer from integer "
4409                                 "without a cast"));
4410
4411       return convert (type, rhs);
4412     }
4413   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4414     {
4415       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4416                               "from pointer without a cast"),
4417                            G_("assignment makes integer from pointer "
4418                               "without a cast"),
4419                            G_("initialization makes integer from pointer "
4420                               "without a cast"),
4421                            G_("return makes integer from pointer "
4422                               "without a cast"));
4423       return convert (type, rhs);
4424     }
4425   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4426     return convert (type, rhs);
4427
4428   switch (errtype)
4429     {
4430     case ic_argpass:
4431     case ic_argpass_nonproto:
4432       /* ??? This should not be an error when inlining calls to
4433          unprototyped functions.  */
4434       error ("incompatible type for argument %d of %qE", parmnum, rname);
4435       break;
4436     case ic_assign:
4437       error ("incompatible types in assignment");
4438       break;
4439     case ic_init:
4440       error ("incompatible types in initialization");
4441       break;
4442     case ic_return:
4443       error ("incompatible types in return");
4444       break;
4445     default:
4446       gcc_unreachable ();
4447     }
4448
4449   return error_mark_node;
4450 }
4451 \f
4452 /* If VALUE is a compound expr all of whose expressions are constant, then
4453    return its value.  Otherwise, return error_mark_node.
4454
4455    This is for handling COMPOUND_EXPRs as initializer elements
4456    which is allowed with a warning when -pedantic is specified.  */
4457
4458 static tree
4459 valid_compound_expr_initializer (tree value, tree endtype)
4460 {
4461   if (TREE_CODE (value) == COMPOUND_EXPR)
4462     {
4463       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4464           == error_mark_node)
4465         return error_mark_node;
4466       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4467                                               endtype);
4468     }
4469   else if (!initializer_constant_valid_p (value, endtype))
4470     return error_mark_node;
4471   else
4472     return value;
4473 }
4474 \f
4475 /* Perform appropriate conversions on the initial value of a variable,
4476    store it in the declaration DECL,
4477    and print any error messages that are appropriate.
4478    If the init is invalid, store an ERROR_MARK.  */
4479
4480 void
4481 store_init_value (tree decl, tree init)
4482 {
4483   tree value, type;
4484
4485   /* If variable's type was invalidly declared, just ignore it.  */
4486
4487   type = TREE_TYPE (decl);
4488   if (TREE_CODE (type) == ERROR_MARK)
4489     return;
4490
4491   /* Digest the specified initializer into an expression.  */
4492
4493   value = digest_init (type, init, true, TREE_STATIC (decl));
4494
4495   /* Store the expression if valid; else report error.  */
4496
4497   if (!in_system_header
4498       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4499     warning (OPT_Wtraditional, "traditional C rejects automatic "
4500              "aggregate initialization");
4501
4502   DECL_INITIAL (decl) = value;
4503
4504   /* ANSI wants warnings about out-of-range constant initializers.  */
4505   STRIP_TYPE_NOPS (value);
4506   if (TREE_STATIC (decl))
4507     constant_expression_warning (value);
4508
4509   /* Check if we need to set array size from compound literal size.  */
4510   if (TREE_CODE (type) == ARRAY_TYPE
4511       && TYPE_DOMAIN (type) == 0
4512       && value != error_mark_node)
4513     {
4514       tree inside_init = init;
4515
4516       STRIP_TYPE_NOPS (inside_init);
4517       inside_init = fold (inside_init);
4518
4519       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4520         {
4521           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4522
4523           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4524             {
4525               /* For int foo[] = (int [3]){1}; we need to set array size
4526                  now since later on array initializer will be just the
4527                  brace enclosed list of the compound literal.  */
4528               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4529               TREE_TYPE (decl) = type;
4530               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4531               layout_type (type);
4532               layout_decl (cldecl, 0);
4533             }
4534         }
4535     }
4536 }
4537 \f
4538 /* Methods for storing and printing names for error messages.  */
4539
4540 /* Implement a spelling stack that allows components of a name to be pushed
4541    and popped.  Each element on the stack is this structure.  */
4542
4543 struct spelling
4544 {
4545   int kind;
4546   union
4547     {
4548       unsigned HOST_WIDE_INT i;
4549       const char *s;
4550     } u;
4551 };
4552
4553 #define SPELLING_STRING 1
4554 #define SPELLING_MEMBER 2
4555 #define SPELLING_BOUNDS 3
4556
4557 static struct spelling *spelling;       /* Next stack element (unused).  */
4558 static struct spelling *spelling_base;  /* Spelling stack base.  */
4559 static int spelling_size;               /* Size of the spelling stack.  */
4560
4561 /* Macros to save and restore the spelling stack around push_... functions.
4562    Alternative to SAVE_SPELLING_STACK.  */
4563
4564 #define SPELLING_DEPTH() (spelling - spelling_base)
4565 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4566
4567 /* Push an element on the spelling stack with type KIND and assign VALUE
4568    to MEMBER.  */
4569
4570 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4571 {                                                                       \
4572   int depth = SPELLING_DEPTH ();                                        \
4573                                                                         \
4574   if (depth >= spelling_size)                                           \
4575     {                                                                   \
4576       spelling_size += 10;                                              \
4577       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4578                                   spelling_size);                       \
4579       RESTORE_SPELLING_DEPTH (depth);                                   \
4580     }                                                                   \
4581                                                                         \
4582   spelling->kind = (KIND);                                              \
4583   spelling->MEMBER = (VALUE);                                           \
4584   spelling++;                                                           \
4585 }
4586
4587 /* Push STRING on the stack.  Printed literally.  */
4588
4589 static void
4590 push_string (const char *string)
4591 {
4592   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4593 }
4594
4595 /* Push a member name on the stack.  Printed as '.' STRING.  */
4596
4597 static void
4598 push_member_name (tree decl)
4599 {
4600   const char *const string
4601     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4602   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4603 }
4604
4605 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4606
4607 static void
4608 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4609 {
4610   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4611 }
4612
4613 /* Compute the maximum size in bytes of the printed spelling.  */
4614
4615 static int
4616 spelling_length (void)
4617 {
4618   int size = 0;
4619   struct spelling *p;
4620
4621   for (p = spelling_base; p < spelling; p++)
4622     {
4623       if (p->kind == SPELLING_BOUNDS)
4624         size += 25;
4625       else
4626         size += strlen (p->u.s) + 1;
4627     }
4628
4629   return size;
4630 }
4631
4632 /* Print the spelling to BUFFER and return it.  */
4633
4634 static char *
4635 print_spelling (char *buffer)
4636 {
4637   char *d = buffer;
4638   struct spelling *p;
4639
4640   for (p = spelling_base; p < spelling; p++)
4641     if (p->kind == SPELLING_BOUNDS)
4642       {
4643         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4644         d += strlen (d);
4645       }
4646     else
4647       {
4648         const char *s;
4649         if (p->kind == SPELLING_MEMBER)
4650           *d++ = '.';
4651         for (s = p->u.s; (*d = *s++); d++)
4652           ;
4653       }
4654   *d++ = '\0';
4655   return buffer;
4656 }
4657
4658 /* Issue an error message for a bad initializer component.
4659    MSGID identifies the message.
4660    The component name is taken from the spelling stack.  */
4661
4662 void
4663 error_init (const char *msgid)
4664 {
4665   char *ofwhat;
4666
4667   error ("%s", _(msgid));
4668   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4669   if (*ofwhat)
4670     error ("(near initialization for %qs)", ofwhat);
4671 }
4672
4673 /* Issue a pedantic warning for a bad initializer component.
4674    MSGID identifies the message.
4675    The component name is taken from the spelling stack.  */
4676
4677 void
4678 pedwarn_init (const char *msgid)
4679 {
4680   char *ofwhat;
4681
4682   pedwarn ("%s", _(msgid));
4683   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4684   if (*ofwhat)
4685     pedwarn ("(near initialization for %qs)", ofwhat);
4686 }
4687
4688 /* Issue a warning for a bad initializer component.
4689    MSGID identifies the message.
4690    The component name is taken from the spelling stack.  */
4691
4692 static void
4693 warning_init (const char *msgid)
4694 {
4695   char *ofwhat;
4696
4697   warning (0, "%s", _(msgid));
4698   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4699   if (*ofwhat)
4700     warning (0, "(near initialization for %qs)", ofwhat);
4701 }
4702 \f
4703 /* If TYPE is an array type and EXPR is a parenthesized string
4704    constant, warn if pedantic that EXPR is being used to initialize an
4705    object of type TYPE.  */
4706
4707 void
4708 maybe_warn_string_init (tree type, struct c_expr expr)
4709 {
4710   if (pedantic
4711       && TREE_CODE (type) == ARRAY_TYPE
4712       && TREE_CODE (expr.value) == STRING_CST
4713       && expr.original_code != STRING_CST)
4714     pedwarn_init ("array initialized from parenthesized string constant");
4715 }
4716
4717 /* Digest the parser output INIT as an initializer for type TYPE.
4718    Return a C expression of type TYPE to represent the initial value.
4719
4720    If INIT is a string constant, STRICT_STRING is true if it is
4721    unparenthesized or we should not warn here for it being parenthesized.
4722    For other types of INIT, STRICT_STRING is not used.
4723
4724    REQUIRE_CONSTANT requests an error if non-constant initializers or
4725    elements are seen.  */
4726
4727 static tree
4728 digest_init (tree type, tree init, bool strict_string, int require_constant)
4729 {
4730   enum tree_code code = TREE_CODE (type);
4731   tree inside_init = init;
4732
4733   if (type == error_mark_node
4734       || !init
4735       || init == error_mark_node
4736       || TREE_TYPE (init) == error_mark_node)
4737     return error_mark_node;
4738
4739   STRIP_TYPE_NOPS (inside_init);
4740
4741   inside_init = fold (inside_init);
4742
4743   /* Initialization of an array of chars from a string constant
4744      optionally enclosed in braces.  */
4745
4746   if (code == ARRAY_TYPE && inside_init
4747       && TREE_CODE (inside_init) == STRING_CST)
4748     {
4749       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4750       /* Note that an array could be both an array of character type
4751          and an array of wchar_t if wchar_t is signed char or unsigned
4752          char.  */
4753       bool char_array = (typ1 == char_type_node
4754                          || typ1 == signed_char_type_node
4755                          || typ1 == unsigned_char_type_node);
4756       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4757       if (char_array || wchar_array)
4758         {
4759           struct c_expr expr;
4760           bool char_string;
4761           expr.value = inside_init;
4762           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4763           maybe_warn_string_init (type, expr);
4764
4765           char_string
4766             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4767                == char_type_node);
4768
4769           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4770                          TYPE_MAIN_VARIANT (type)))
4771             return inside_init;
4772
4773           if (!wchar_array && !char_string)
4774             {
4775               error_init ("char-array initialized from wide string");
4776               return error_mark_node;
4777             }
4778           if (char_string && !char_array)
4779             {
4780               error_init ("wchar_t-array initialized from non-wide string");
4781               return error_mark_node;
4782             }
4783
4784           TREE_TYPE (inside_init) = type;
4785           if (TYPE_DOMAIN (type) != 0
4786               && TYPE_SIZE (type) != 0
4787               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4788               /* Subtract 1 (or sizeof (wchar_t))
4789                  because it's ok to ignore the terminating null char
4790                  that is counted in the length of the constant.  */
4791               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4792                                        TREE_STRING_LENGTH (inside_init)
4793                                        - ((TYPE_PRECISION (typ1)
4794                                            != TYPE_PRECISION (char_type_node))
4795                                           ? (TYPE_PRECISION (wchar_type_node)
4796                                              / BITS_PER_UNIT)
4797                                           : 1)))
4798             pedwarn_init ("initializer-string for array of chars is too long");
4799
4800           return inside_init;
4801         }
4802       else if (INTEGRAL_TYPE_P (typ1))
4803         {
4804           error_init ("array of inappropriate type initialized "
4805                       "from string constant");
4806           return error_mark_node;
4807         }
4808     }
4809
4810   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4811      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4812      below and handle as a constructor.  */
4813   if (code == VECTOR_TYPE
4814       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4815       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4816       && TREE_CONSTANT (inside_init))
4817     {
4818       if (TREE_CODE (inside_init) == VECTOR_CST
4819           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4820                         TYPE_MAIN_VARIANT (type)))
4821         return inside_init;
4822
4823       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4824         {
4825           unsigned HOST_WIDE_INT ix;
4826           tree value;
4827           bool constant_p = true;
4828
4829           /* Iterate through elements and check if all constructor
4830              elements are *_CSTs.  */
4831           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4832             if (!CONSTANT_CLASS_P (value))
4833               {
4834                 constant_p = false;
4835                 break;
4836               }
4837
4838           if (constant_p)
4839             return build_vector_from_ctor (type,
4840                                            CONSTRUCTOR_ELTS (inside_init));
4841         }
4842     }
4843
4844   /* Any type can be initialized
4845      from an expression of the same type, optionally with braces.  */
4846
4847   if (inside_init && TREE_TYPE (inside_init) != 0
4848       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4849                      TYPE_MAIN_VARIANT (type))
4850           || (code == ARRAY_TYPE
4851               && comptypes (TREE_TYPE (inside_init), type))
4852           || (code == VECTOR_TYPE
4853               && comptypes (TREE_TYPE (inside_init), type))
4854           || (code == POINTER_TYPE
4855               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4856               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4857                             TREE_TYPE (type)))))
4858     {
4859       if (code == POINTER_TYPE)
4860         {
4861           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4862             {
4863               if (TREE_CODE (inside_init) == STRING_CST
4864                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4865                 inside_init = array_to_pointer_conversion (inside_init);
4866               else
4867                 {
4868                   error_init ("invalid use of non-lvalue array");
4869                   return error_mark_node;
4870                 }
4871             }
4872         }
4873
4874       if (code == VECTOR_TYPE)
4875         /* Although the types are compatible, we may require a
4876            conversion.  */
4877         inside_init = convert (type, inside_init);
4878
4879       if (require_constant
4880           && (code == VECTOR_TYPE || !flag_isoc99)
4881           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4882         {
4883           /* As an extension, allow initializing objects with static storage
4884              duration with compound literals (which are then treated just as
4885              the brace enclosed list they contain).  Also allow this for
4886              vectors, as we can only assign them with compound literals.  */
4887           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4888           inside_init = DECL_INITIAL (decl);
4889         }
4890
4891       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4892           && TREE_CODE (inside_init) != CONSTRUCTOR)
4893         {
4894           error_init ("array initialized from non-constant array expression");
4895           return error_mark_node;
4896         }
4897
4898       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4899         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4900
4901       /* Compound expressions can only occur here if -pedantic or
4902          -pedantic-errors is specified.  In the later case, we always want
4903          an error.  In the former case, we simply want a warning.  */
4904       if (require_constant && pedantic
4905           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4906         {
4907           inside_init
4908             = valid_compound_expr_initializer (inside_init,
4909                                                TREE_TYPE (inside_init));
4910           if (inside_init == error_mark_node)
4911             error_init ("initializer element is not constant");
4912           else
4913             pedwarn_init ("initializer element is not constant");
4914           if (flag_pedantic_errors)
4915             inside_init = error_mark_node;
4916         }
4917       else if (require_constant
4918                && !initializer_constant_valid_p (inside_init,
4919                                                  TREE_TYPE (inside_init)))
4920         {
4921           error_init ("initializer element is not constant");
4922           inside_init = error_mark_node;
4923         }
4924
4925       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4926       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4927         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4928                                               NULL_TREE, 0);
4929       return inside_init;
4930     }
4931
4932   /* Handle scalar types, including conversions.  */
4933
4934   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4935       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4936       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4937     {
4938       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4939           && (TREE_CODE (init) == STRING_CST
4940               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4941         init = array_to_pointer_conversion (init);
4942       inside_init
4943         = convert_for_assignment (type, init, ic_init,
4944                                   NULL_TREE, NULL_TREE, 0);
4945
4946       /* Check to see if we have already given an error message.  */
4947       if (inside_init == error_mark_node)
4948         ;
4949       else if (require_constant && !TREE_CONSTANT (inside_init))
4950         {
4951           error_init ("initializer element is not constant");
4952           inside_init = error_mark_node;
4953         }
4954       else if (require_constant
4955                && !initializer_constant_valid_p (inside_init,
4956                                                  TREE_TYPE (inside_init)))
4957         {
4958           error_init ("initializer element is not computable at load time");
4959           inside_init = error_mark_node;
4960         }
4961
4962       return inside_init;
4963     }
4964
4965   /* Come here only for records and arrays.  */
4966
4967   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4968     {
4969       error_init ("variable-sized object may not be initialized");
4970       return error_mark_node;
4971     }
4972
4973   error_init ("invalid initializer");
4974   return error_mark_node;
4975 }
4976 \f
4977 /* Handle initializers that use braces.  */
4978
4979 /* Type of object we are accumulating a constructor for.
4980    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4981 static tree constructor_type;
4982
4983 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4984    left to fill.  */
4985 static tree constructor_fields;
4986
4987 /* For an ARRAY_TYPE, this is the specified index
4988    at which to store the next element we get.  */
4989 static tree constructor_index;
4990
4991 /* For an ARRAY_TYPE, this is the maximum index.  */
4992 static tree constructor_max_index;
4993
4994 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4995 static tree constructor_unfilled_fields;
4996
4997 /* For an ARRAY_TYPE, this is the index of the first element
4998    not yet written out.  */
4999 static tree constructor_unfilled_index;
5000
5001 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5002    This is so we can generate gaps between fields, when appropriate.  */
5003 static tree constructor_bit_index;
5004
5005 /* If we are saving up the elements rather than allocating them,
5006    this is the list of elements so far (in reverse order,
5007    most recent first).  */
5008 static VEC(constructor_elt,gc) *constructor_elements;
5009
5010 /* 1 if constructor should be incrementally stored into a constructor chain,
5011    0 if all the elements should be kept in AVL tree.  */
5012 static int constructor_incremental;
5013
5014 /* 1 if so far this constructor's elements are all compile-time constants.  */
5015 static int constructor_constant;
5016
5017 /* 1 if so far this constructor's elements are all valid address constants.  */
5018 static int constructor_simple;
5019
5020 /* 1 if this constructor is erroneous so far.  */
5021 static int constructor_erroneous;
5022
5023 /* Structure for managing pending initializer elements, organized as an
5024    AVL tree.  */
5025
5026 struct init_node
5027 {
5028   struct init_node *left, *right;
5029   struct init_node *parent;
5030   int balance;
5031   tree purpose;
5032   tree value;
5033 };
5034
5035 /* Tree of pending elements at this constructor level.
5036    These are elements encountered out of order
5037    which belong at places we haven't reached yet in actually
5038    writing the output.
5039    Will never hold tree nodes across GC runs.  */
5040 static struct init_node *constructor_pending_elts;
5041
5042 /* The SPELLING_DEPTH of this constructor.  */
5043 static int constructor_depth;
5044
5045 /* DECL node for which an initializer is being read.
5046    0 means we are reading a constructor expression
5047    such as (struct foo) {...}.  */
5048 static tree constructor_decl;
5049
5050 /* Nonzero if this is an initializer for a top-level decl.  */
5051 static int constructor_top_level;
5052
5053 /* Nonzero if there were any member designators in this initializer.  */
5054 static int constructor_designated;
5055
5056 /* Nesting depth of designator list.  */
5057 static int designator_depth;
5058
5059 /* Nonzero if there were diagnosed errors in this designator list.  */
5060 static int designator_erroneous;
5061
5062 \f
5063 /* This stack has a level for each implicit or explicit level of
5064    structuring in the initializer, including the outermost one.  It
5065    saves the values of most of the variables above.  */
5066
5067 struct constructor_range_stack;
5068
5069 struct constructor_stack
5070 {
5071   struct constructor_stack *next;
5072   tree type;
5073   tree fields;
5074   tree index;
5075   tree max_index;
5076   tree unfilled_index;
5077   tree unfilled_fields;
5078   tree bit_index;
5079   VEC(constructor_elt,gc) *elements;
5080   struct init_node *pending_elts;
5081   int offset;
5082   int depth;
5083   /* If value nonzero, this value should replace the entire
5084      constructor at this level.  */
5085   struct c_expr replacement_value;
5086   struct constructor_range_stack *range_stack;
5087   char constant;
5088   char simple;
5089   char implicit;
5090   char erroneous;
5091   char outer;
5092   char incremental;
5093   char designated;
5094 };
5095
5096 static struct constructor_stack *constructor_stack;
5097
5098 /* This stack represents designators from some range designator up to
5099    the last designator in the list.  */
5100
5101 struct constructor_range_stack
5102 {
5103   struct constructor_range_stack *next, *prev;
5104   struct constructor_stack *stack;
5105   tree range_start;
5106   tree index;
5107   tree range_end;
5108   tree fields;
5109 };
5110
5111 static struct constructor_range_stack *constructor_range_stack;
5112
5113 /* This stack records separate initializers that are nested.
5114    Nested initializers can't happen in ANSI C, but GNU C allows them
5115    in cases like { ... (struct foo) { ... } ... }.  */
5116
5117 struct initializer_stack
5118 {
5119   struct initializer_stack *next;
5120   tree decl;
5121   struct constructor_stack *constructor_stack;
5122   struct constructor_range_stack *constructor_range_stack;
5123   VEC(constructor_elt,gc) *elements;
5124   struct spelling *spelling;
5125   struct spelling *spelling_base;
5126   int spelling_size;
5127   char top_level;
5128   char require_constant_value;
5129   char require_constant_elements;
5130 };
5131
5132 static struct initializer_stack *initializer_stack;
5133 \f
5134 /* Prepare to parse and output the initializer for variable DECL.  */
5135
5136 void
5137 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5138 {
5139   const char *locus;
5140   struct initializer_stack *p = XNEW (struct initializer_stack);
5141
5142   p->decl = constructor_decl;
5143   p->require_constant_value = require_constant_value;
5144   p->require_constant_elements = require_constant_elements;
5145   p->constructor_stack = constructor_stack;
5146   p->constructor_range_stack = constructor_range_stack;
5147   p->elements = constructor_elements;
5148   p->spelling = spelling;
5149   p->spelling_base = spelling_base;
5150   p->spelling_size = spelling_size;
5151   p->top_level = constructor_top_level;
5152   p->next = initializer_stack;
5153   initializer_stack = p;
5154
5155   constructor_decl = decl;
5156   constructor_designated = 0;
5157   constructor_top_level = top_level;
5158
5159   if (decl != 0 && decl != error_mark_node)
5160     {
5161       require_constant_value = TREE_STATIC (decl);
5162       require_constant_elements
5163         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5164            /* For a scalar, you can always use any value to initialize,
5165               even within braces.  */
5166            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5167                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5168                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5169                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5170       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5171     }
5172   else
5173     {
5174       require_constant_value = 0;
5175       require_constant_elements = 0;
5176       locus = "(anonymous)";
5177     }
5178
5179   constructor_stack = 0;
5180   constructor_range_stack = 0;
5181
5182   missing_braces_mentioned = 0;
5183
5184   spelling_base = 0;
5185   spelling_size = 0;
5186   RESTORE_SPELLING_DEPTH (0);
5187
5188   if (locus)
5189     push_string (locus);
5190 }
5191
5192 void
5193 finish_init (void)
5194 {
5195   struct initializer_stack *p = initializer_stack;
5196
5197   /* Free the whole constructor stack of this initializer.  */
5198   while (constructor_stack)
5199     {
5200       struct constructor_stack *q = constructor_stack;
5201       constructor_stack = q->next;
5202       free (q);
5203     }
5204
5205   gcc_assert (!constructor_range_stack);
5206
5207   /* Pop back to the data of the outer initializer (if any).  */
5208   free (spelling_base);
5209
5210   constructor_decl = p->decl;
5211   require_constant_value = p->require_constant_value;
5212   require_constant_elements = p->require_constant_elements;
5213   constructor_stack = p->constructor_stack;
5214   constructor_range_stack = p->constructor_range_stack;
5215   constructor_elements = p->elements;
5216   spelling = p->spelling;
5217   spelling_base = p->spelling_base;
5218   spelling_size = p->spelling_size;
5219   constructor_top_level = p->top_level;
5220   initializer_stack = p->next;
5221   free (p);
5222 }
5223 \f
5224 /* Call here when we see the initializer is surrounded by braces.
5225    This is instead of a call to push_init_level;
5226    it is matched by a call to pop_init_level.
5227
5228    TYPE is the type to initialize, for a constructor expression.
5229    For an initializer for a decl, TYPE is zero.  */
5230
5231 void
5232 really_start_incremental_init (tree type)
5233 {
5234   struct constructor_stack *p = XNEW (struct constructor_stack);
5235
5236   if (type == 0)
5237     type = TREE_TYPE (constructor_decl);
5238
5239   if (targetm.vector_opaque_p (type))
5240     error ("opaque vector types cannot be initialized");
5241
5242   p->type = constructor_type;
5243   p->fields = constructor_fields;
5244   p->index = constructor_index;
5245   p->max_index = constructor_max_index;
5246   p->unfilled_index = constructor_unfilled_index;
5247   p->unfilled_fields = constructor_unfilled_fields;
5248   p->bit_index = constructor_bit_index;
5249   p->elements = constructor_elements;
5250   p->constant = constructor_constant;
5251   p->simple = constructor_simple;
5252   p->erroneous = constructor_erroneous;
5253   p->pending_elts = constructor_pending_elts;
5254   p->depth = constructor_depth;
5255   p->replacement_value.value = 0;
5256   p->replacement_value.original_code = ERROR_MARK;
5257   p->implicit = 0;
5258   p->range_stack = 0;
5259   p->outer = 0;
5260   p->incremental = constructor_incremental;
5261   p->designated = constructor_designated;
5262   p->next = 0;
5263   constructor_stack = p;
5264
5265   constructor_constant = 1;
5266   constructor_simple = 1;
5267   constructor_depth = SPELLING_DEPTH ();
5268   constructor_elements = 0;
5269   constructor_pending_elts = 0;
5270   constructor_type = type;
5271   constructor_incremental = 1;
5272   constructor_designated = 0;
5273   designator_depth = 0;
5274   designator_erroneous = 0;
5275
5276   if (TREE_CODE (constructor_type) == RECORD_TYPE
5277       || TREE_CODE (constructor_type) == UNION_TYPE)
5278     {
5279       constructor_fields = TYPE_FIELDS (constructor_type);
5280       /* Skip any nameless bit fields at the beginning.  */
5281       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5282              && DECL_NAME (constructor_fields) == 0)
5283         constructor_fields = TREE_CHAIN (constructor_fields);
5284
5285       constructor_unfilled_fields = constructor_fields;
5286       constructor_bit_index = bitsize_zero_node;
5287     }
5288   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5289     {
5290       if (TYPE_DOMAIN (constructor_type))
5291         {
5292           constructor_max_index
5293             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5294
5295           /* Detect non-empty initializations of zero-length arrays.  */
5296           if (constructor_max_index == NULL_TREE
5297               && TYPE_SIZE (constructor_type))
5298             constructor_max_index = build_int_cst (NULL_TREE, -1);
5299
5300           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5301              to initialize VLAs will cause a proper error; avoid tree
5302              checking errors as well by setting a safe value.  */
5303           if (constructor_max_index
5304               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5305             constructor_max_index = build_int_cst (NULL_TREE, -1);
5306
5307           constructor_index
5308             = convert (bitsizetype,
5309                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5310         }
5311       else
5312         {
5313           constructor_index = bitsize_zero_node;
5314           constructor_max_index = NULL_TREE;
5315         }
5316
5317       constructor_unfilled_index = constructor_index;
5318     }
5319   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5320     {
5321       /* Vectors are like simple fixed-size arrays.  */
5322       constructor_max_index =
5323         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5324       constructor_index = bitsize_zero_node;
5325       constructor_unfilled_index = constructor_index;
5326     }
5327   else
5328     {
5329       /* Handle the case of int x = {5}; */
5330       constructor_fields = constructor_type;
5331       constructor_unfilled_fields = constructor_type;
5332     }
5333 }
5334 \f
5335 /* Push down into a subobject, for initialization.
5336    If this is for an explicit set of braces, IMPLICIT is 0.
5337    If it is because the next element belongs at a lower level,
5338    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5339
5340 void
5341 push_init_level (int implicit)
5342 {
5343   struct constructor_stack *p;
5344   tree value = NULL_TREE;
5345
5346   /* If we've exhausted any levels that didn't have braces,
5347      pop them now.  If implicit == 1, this will have been done in
5348      process_init_element; do not repeat it here because in the case
5349      of excess initializers for an empty aggregate this leads to an
5350      infinite cycle of popping a level and immediately recreating
5351      it.  */
5352   if (implicit != 1)
5353     {
5354       while (constructor_stack->implicit)
5355         {
5356           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5357                || TREE_CODE (constructor_type) == UNION_TYPE)
5358               && constructor_fields == 0)
5359             process_init_element (pop_init_level (1));
5360           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5361                    && constructor_max_index
5362                    && tree_int_cst_lt (constructor_max_index,
5363                                        constructor_index))
5364             process_init_element (pop_init_level (1));
5365           else
5366             break;
5367         }
5368     }
5369
5370   /* Unless this is an explicit brace, we need to preserve previous
5371      content if any.  */
5372   if (implicit)
5373     {
5374       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5375            || TREE_CODE (constructor_type) == UNION_TYPE)
5376           && constructor_fields)
5377         value = find_init_member (constructor_fields);
5378       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5379         value = find_init_member (constructor_index);
5380     }
5381
5382   p = XNEW (struct constructor_stack);
5383   p->type = constructor_type;
5384   p->fields = constructor_fields;
5385   p->index = constructor_index;
5386   p->max_index = constructor_max_index;
5387   p->unfilled_index = constructor_unfilled_index;
5388   p->unfilled_fields = constructor_unfilled_fields;
5389   p->bit_index = constructor_bit_index;
5390   p->elements = constructor_elements;
5391   p->constant = constructor_constant;
5392   p->simple = constructor_simple;
5393   p->erroneous = constructor_erroneous;
5394   p->pending_elts = constructor_pending_elts;
5395   p->depth = constructor_depth;
5396   p->replacement_value.value = 0;
5397   p->replacement_value.original_code = ERROR_MARK;
5398   p->implicit = implicit;
5399   p->outer = 0;
5400   p->incremental = constructor_incremental;
5401   p->designated = constructor_designated;
5402   p->next = constructor_stack;
5403   p->range_stack = 0;
5404   constructor_stack = p;
5405
5406   constructor_constant = 1;
5407   constructor_simple = 1;
5408   constructor_depth = SPELLING_DEPTH ();
5409   constructor_elements = 0;
5410   constructor_incremental = 1;
5411   constructor_designated = 0;
5412   constructor_pending_elts = 0;
5413   if (!implicit)
5414     {
5415       p->range_stack = constructor_range_stack;
5416       constructor_range_stack = 0;
5417       designator_depth = 0;
5418       designator_erroneous = 0;
5419     }
5420
5421   /* Don't die if an entire brace-pair level is superfluous
5422      in the containing level.  */
5423   if (constructor_type == 0)
5424     ;
5425   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5426            || TREE_CODE (constructor_type) == UNION_TYPE)
5427     {
5428       /* Don't die if there are extra init elts at the end.  */
5429       if (constructor_fields == 0)
5430         constructor_type = 0;
5431       else
5432         {
5433           constructor_type = TREE_TYPE (constructor_fields);
5434           push_member_name (constructor_fields);
5435           constructor_depth++;
5436         }
5437     }
5438   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5439     {
5440       constructor_type = TREE_TYPE (constructor_type);
5441       push_array_bounds (tree_low_cst (constructor_index, 1));
5442       constructor_depth++;
5443     }
5444
5445   if (constructor_type == 0)
5446     {
5447       error_init ("extra brace group at end of initializer");
5448       constructor_fields = 0;
5449       constructor_unfilled_fields = 0;
5450       return;
5451     }
5452
5453   if (value && TREE_CODE (value) == CONSTRUCTOR)
5454     {
5455       constructor_constant = TREE_CONSTANT (value);
5456       constructor_simple = TREE_STATIC (value);
5457       constructor_elements = CONSTRUCTOR_ELTS (value);
5458       if (!VEC_empty (constructor_elt, constructor_elements)
5459           && (TREE_CODE (constructor_type) == RECORD_TYPE
5460               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5461         set_nonincremental_init ();
5462     }
5463
5464   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5465     {
5466       missing_braces_mentioned = 1;
5467       warning_init ("missing braces around initializer");
5468     }
5469
5470   if (TREE_CODE (constructor_type) == RECORD_TYPE
5471            || TREE_CODE (constructor_type) == UNION_TYPE)
5472     {
5473       constructor_fields = TYPE_FIELDS (constructor_type);
5474       /* Skip any nameless bit fields at the beginning.  */
5475       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5476              && DECL_NAME (constructor_fields) == 0)
5477         constructor_fields = TREE_CHAIN (constructor_fields);
5478
5479       constructor_unfilled_fields = constructor_fields;
5480       constructor_bit_index = bitsize_zero_node;
5481     }
5482   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5483     {
5484       /* Vectors are like simple fixed-size arrays.  */
5485       constructor_max_index =
5486         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5487       constructor_index = convert (bitsizetype, integer_zero_node);
5488       constructor_unfilled_index = constructor_index;
5489     }
5490   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5491     {
5492       if (TYPE_DOMAIN (constructor_type))
5493         {
5494           constructor_max_index
5495             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5496
5497           /* Detect non-empty initializations of zero-length arrays.  */
5498           if (constructor_max_index == NULL_TREE
5499               && TYPE_SIZE (constructor_type))
5500             constructor_max_index = build_int_cst (NULL_TREE, -1);
5501
5502           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5503              to initialize VLAs will cause a proper error; avoid tree
5504              checking errors as well by setting a safe value.  */
5505           if (constructor_max_index
5506               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5507             constructor_max_index = build_int_cst (NULL_TREE, -1);
5508
5509           constructor_index
5510             = convert (bitsizetype,
5511                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5512         }
5513       else
5514         constructor_index = bitsize_zero_node;
5515
5516       constructor_unfilled_index = constructor_index;
5517       if (value && TREE_CODE (value) == STRING_CST)
5518         {
5519           /* We need to split the char/wchar array into individual
5520              characters, so that we don't have to special case it
5521              everywhere.  */
5522           set_nonincremental_init_from_string (value);
5523         }
5524     }
5525   else
5526     {
5527       if (constructor_type != error_mark_node)
5528         warning_init ("braces around scalar initializer");
5529       constructor_fields = constructor_type;
5530       constructor_unfilled_fields = constructor_type;
5531     }
5532 }
5533
5534 /* At the end of an implicit or explicit brace level,
5535    finish up that level of constructor.  If a single expression
5536    with redundant braces initialized that level, return the
5537    c_expr structure for that expression.  Otherwise, the original_code
5538    element is set to ERROR_MARK.
5539    If we were outputting the elements as they are read, return 0 as the value
5540    from inner levels (process_init_element ignores that),
5541    but return error_mark_node as the value from the outermost level
5542    (that's what we want to put in DECL_INITIAL).
5543    Otherwise, return a CONSTRUCTOR expression as the value.  */
5544
5545 struct c_expr
5546 pop_init_level (int implicit)
5547 {
5548   struct constructor_stack *p;
5549   struct c_expr ret;
5550   ret.value = 0;
5551   ret.original_code = ERROR_MARK;
5552
5553   if (implicit == 0)
5554     {
5555       /* When we come to an explicit close brace,
5556          pop any inner levels that didn't have explicit braces.  */
5557       while (constructor_stack->implicit)
5558         process_init_element (pop_init_level (1));
5559
5560       gcc_assert (!constructor_range_stack);
5561     }
5562
5563   /* Now output all pending elements.  */
5564   constructor_incremental = 1;
5565   output_pending_init_elements (1);
5566
5567   p = constructor_stack;
5568
5569   /* Error for initializing a flexible array member, or a zero-length
5570      array member in an inappropriate context.  */
5571   if (constructor_type && constructor_fields
5572       && TREE_CODE (constructor_type) == ARRAY_TYPE
5573       && TYPE_DOMAIN (constructor_type)
5574       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5575     {
5576       /* Silently discard empty initializations.  The parser will
5577          already have pedwarned for empty brackets.  */
5578       if (integer_zerop (constructor_unfilled_index))
5579         constructor_type = NULL_TREE;
5580       else
5581         {
5582           gcc_assert (!TYPE_SIZE (constructor_type));
5583
5584           if (constructor_depth > 2)
5585             error_init ("initialization of flexible array member in a nested context");
5586           else if (pedantic)
5587             pedwarn_init ("initialization of a flexible array member");
5588
5589           /* We have already issued an error message for the existence
5590              of a flexible array member not at the end of the structure.
5591              Discard the initializer so that we do not die later.  */
5592           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5593             constructor_type = NULL_TREE;
5594         }
5595     }
5596
5597   /* Warn when some struct elements are implicitly initialized to zero.  */
5598   if (warn_missing_field_initializers
5599       && constructor_type
5600       && TREE_CODE (constructor_type) == RECORD_TYPE
5601       && constructor_unfilled_fields)
5602     {
5603         /* Do not warn for flexible array members or zero-length arrays.  */
5604         while (constructor_unfilled_fields
5605                && (!DECL_SIZE (constructor_unfilled_fields)
5606                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5607           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5608
5609         /* Do not warn if this level of the initializer uses member
5610            designators; it is likely to be deliberate.  */
5611         if (constructor_unfilled_fields && !constructor_designated)
5612           {
5613             push_member_name (constructor_unfilled_fields);
5614             warning_init ("missing initializer");
5615             RESTORE_SPELLING_DEPTH (constructor_depth);
5616           }
5617     }
5618
5619   /* Pad out the end of the structure.  */
5620   if (p->replacement_value.value)
5621     /* If this closes a superfluous brace pair,
5622        just pass out the element between them.  */
5623     ret = p->replacement_value;
5624   else if (constructor_type == 0)
5625     ;
5626   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5627            && TREE_CODE (constructor_type) != UNION_TYPE
5628            && TREE_CODE (constructor_type) != ARRAY_TYPE
5629            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5630     {
5631       /* A nonincremental scalar initializer--just return
5632          the element, after verifying there is just one.  */
5633       if (VEC_empty (constructor_elt,constructor_elements))
5634         {
5635           if (!constructor_erroneous)
5636             error_init ("empty scalar initializer");
5637           ret.value = error_mark_node;
5638         }
5639       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5640         {
5641           error_init ("extra elements in scalar initializer");
5642           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5643         }
5644       else
5645         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5646     }
5647   else
5648     {
5649       if (constructor_erroneous)
5650         ret.value = error_mark_node;
5651       else
5652         {
5653           ret.value = build_constructor (constructor_type,
5654                                          constructor_elements);
5655           if (constructor_constant)
5656             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5657           if (constructor_constant && constructor_simple)
5658             TREE_STATIC (ret.value) = 1;
5659         }
5660     }
5661
5662   constructor_type = p->type;
5663   constructor_fields = p->fields;
5664   constructor_index = p->index;
5665   constructor_max_index = p->max_index;
5666   constructor_unfilled_index = p->unfilled_index;
5667   constructor_unfilled_fields = p->unfilled_fields;
5668   constructor_bit_index = p->bit_index;
5669   constructor_elements = p->elements;
5670   constructor_constant = p->constant;
5671   constructor_simple = p->simple;
5672   constructor_erroneous = p->erroneous;
5673   constructor_incremental = p->incremental;
5674   constructor_designated = p->designated;
5675   constructor_pending_elts = p->pending_elts;
5676   constructor_depth = p->depth;
5677   if (!p->implicit)
5678     constructor_range_stack = p->range_stack;
5679   RESTORE_SPELLING_DEPTH (constructor_depth);
5680
5681   constructor_stack = p->next;
5682   free (p);
5683
5684   if (ret.value == 0 && constructor_stack == 0)
5685     ret.value = error_mark_node;
5686   return ret;
5687 }
5688
5689 /* Common handling for both array range and field name designators.
5690    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5691
5692 static int
5693 set_designator (int array)
5694 {
5695   tree subtype;
5696   enum tree_code subcode;
5697
5698   /* Don't die if an entire brace-pair level is superfluous
5699      in the containing level.  */
5700   if (constructor_type == 0)
5701     return 1;
5702
5703   /* If there were errors in this designator list already, bail out
5704      silently.  */
5705   if (designator_erroneous)
5706     return 1;
5707
5708   if (!designator_depth)
5709     {
5710       gcc_assert (!constructor_range_stack);
5711
5712       /* Designator list starts at the level of closest explicit
5713          braces.  */
5714       while (constructor_stack->implicit)
5715         process_init_element (pop_init_level (1));
5716       constructor_designated = 1;
5717       return 0;
5718     }
5719
5720   switch (TREE_CODE (constructor_type))
5721     {
5722     case  RECORD_TYPE:
5723     case  UNION_TYPE:
5724       subtype = TREE_TYPE (constructor_fields);
5725       if (subtype != error_mark_node)
5726         subtype = TYPE_MAIN_VARIANT (subtype);
5727       break;
5728     case ARRAY_TYPE:
5729       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5730       break;
5731     default:
5732       gcc_unreachable ();
5733     }
5734
5735   subcode = TREE_CODE (subtype);
5736   if (array && subcode != ARRAY_TYPE)
5737     {
5738       error_init ("array index in non-array initializer");
5739       return 1;
5740     }
5741   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5742     {
5743       error_init ("field name not in record or union initializer");
5744       return 1;
5745     }
5746
5747   constructor_designated = 1;
5748   push_init_level (2);
5749   return 0;
5750 }
5751
5752 /* If there are range designators in designator list, push a new designator
5753    to constructor_range_stack.  RANGE_END is end of such stack range or
5754    NULL_TREE if there is no range designator at this level.  */
5755
5756 static void
5757 push_range_stack (tree range_end)
5758 {
5759   struct constructor_range_stack *p;
5760
5761   p = GGC_NEW (struct constructor_range_stack);
5762   p->prev = constructor_range_stack;
5763   p->next = 0;
5764   p->fields = constructor_fields;
5765   p->range_start = constructor_index;
5766   p->index = constructor_index;
5767   p->stack = constructor_stack;
5768   p->range_end = range_end;
5769   if (constructor_range_stack)
5770     constructor_range_stack->next = p;
5771   constructor_range_stack = p;
5772 }
5773
5774 /* Within an array initializer, specify the next index to be initialized.
5775    FIRST is that index.  If LAST is nonzero, then initialize a range
5776    of indices, running from FIRST through LAST.  */
5777
5778 void
5779 set_init_index (tree first, tree last)
5780 {
5781   if (set_designator (1))
5782     return;
5783
5784   designator_erroneous = 1;
5785
5786   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5787       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5788     {
5789       error_init ("array index in initializer not of integer type");
5790       return;
5791     }
5792
5793   if (TREE_CODE (first) != INTEGER_CST)
5794     error_init ("nonconstant array index in initializer");
5795   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5796     error_init ("nonconstant array index in initializer");
5797   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5798     error_init ("array index in non-array initializer");
5799   else if (tree_int_cst_sgn (first) == -1)
5800     error_init ("array index in initializer exceeds array bounds");
5801   else if (constructor_max_index
5802            && tree_int_cst_lt (constructor_max_index, first))
5803     error_init ("array index in initializer exceeds array bounds");
5804   else
5805     {
5806       constructor_index = convert (bitsizetype, first);
5807
5808       if (last)
5809         {
5810           if (tree_int_cst_equal (first, last))
5811             last = 0;
5812           else if (tree_int_cst_lt (last, first))
5813             {
5814               error_init ("empty index range in initializer");
5815               last = 0;
5816             }
5817           else
5818             {
5819               last = convert (bitsizetype, last);
5820               if (constructor_max_index != 0
5821                   && tree_int_cst_lt (constructor_max_index, last))
5822                 {
5823                   error_init ("array index range in initializer exceeds array bounds");
5824                   last = 0;
5825                 }
5826             }
5827         }
5828
5829       designator_depth++;
5830       designator_erroneous = 0;
5831       if (constructor_range_stack || last)
5832         push_range_stack (last);
5833     }
5834 }
5835
5836 /* Within a struct initializer, specify the next field to be initialized.  */
5837
5838 void
5839 set_init_label (tree fieldname)
5840 {
5841   tree tail;
5842
5843   if (set_designator (0))
5844     return;
5845
5846   designator_erroneous = 1;
5847
5848   if (TREE_CODE (constructor_type) != RECORD_TYPE
5849       && TREE_CODE (constructor_type) != UNION_TYPE)
5850     {
5851       error_init ("field name not in record or union initializer");
5852       return;
5853     }
5854
5855   for (tail = TYPE_FIELDS (constructor_type); tail;
5856        tail = TREE_CHAIN (tail))
5857     {
5858       if (DECL_NAME (tail) == fieldname)
5859         break;
5860     }
5861
5862   if (tail == 0)
5863     error ("unknown field %qE specified in initializer", fieldname);
5864   else
5865     {
5866       constructor_fields = tail;
5867       designator_depth++;
5868       designator_erroneous = 0;
5869       if (constructor_range_stack)
5870         push_range_stack (NULL_TREE);
5871     }
5872 }
5873 \f
5874 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5875    identifies the initializer, either array index or field in a structure.
5876    VALUE is the value of that index or field.  */
5877
5878 static void
5879 add_pending_init (tree purpose, tree value)
5880 {
5881   struct init_node *p, **q, *r;
5882
5883   q = &constructor_pending_elts;
5884   p = 0;
5885
5886   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5887     {
5888       while (*q != 0)
5889         {
5890           p = *q;
5891           if (tree_int_cst_lt (purpose, p->purpose))
5892             q = &p->left;
5893           else if (tree_int_cst_lt (p->purpose, purpose))
5894             q = &p->right;
5895           else
5896             {
5897               if (TREE_SIDE_EFFECTS (p->value))
5898                 warning_init ("initialized field with side-effects overwritten");
5899               else if (warn_override_init)
5900                 warning_init ("initialized field overwritten");
5901               p->value = value;
5902               return;
5903             }
5904         }
5905     }
5906   else
5907     {
5908       tree bitpos;
5909
5910       bitpos = bit_position (purpose);
5911       while (*q != NULL)
5912         {
5913           p = *q;
5914           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5915             q = &p->left;
5916           else if (p->purpose != purpose)
5917             q = &p->right;
5918           else
5919             {
5920               if (TREE_SIDE_EFFECTS (p->value))
5921                 warning_init ("initialized field with side-effects overwritten");
5922               else if (warn_override_init)
5923                 warning_init ("initialized field overwritten");
5924               p->value = value;
5925               return;
5926             }
5927         }
5928     }
5929
5930   r = GGC_NEW (struct init_node);
5931   r->purpose = purpose;
5932   r->value = value;
5933
5934   *q = r;
5935   r->parent = p;
5936   r->left = 0;
5937   r->right = 0;
5938   r->balance = 0;
5939
5940   while (p)
5941     {
5942       struct init_node *s;
5943
5944       if (r == p->left)
5945         {
5946           if (p->balance == 0)
5947             p->balance = -1;
5948           else if (p->balance < 0)
5949             {
5950               if (r->balance < 0)
5951                 {
5952                   /* L rotation.  */
5953                   p->left = r->right;
5954                   if (p->left)
5955                     p->left->parent = p;
5956                   r->right = p;
5957
5958                   p->balance = 0;
5959                   r->balance = 0;
5960
5961                   s = p->parent;
5962                   p->parent = r;
5963                   r->parent = s;
5964                   if (s)
5965                     {
5966                       if (s->left == p)
5967                         s->left = r;
5968                       else
5969                         s->right = r;
5970                     }
5971                   else
5972                     constructor_pending_elts = r;
5973                 }
5974               else
5975                 {
5976                   /* LR rotation.  */
5977                   struct init_node *t = r->right;
5978
5979                   r->right = t->left;
5980                   if (r->right)
5981                     r->right->parent = r;
5982                   t->left = r;
5983
5984                   p->left = t->right;
5985                   if (p->left)
5986                     p->left->parent = p;
5987                   t->right = p;
5988
5989                   p->balance = t->balance < 0;
5990                   r->balance = -(t->balance > 0);
5991                   t->balance = 0;
5992
5993                   s = p->parent;
5994                   p->parent = t;
5995                   r->parent = t;
5996                   t->parent = s;
5997                   if (s)
5998                     {
5999                       if (s->left == p)
6000                         s->left = t;
6001                       else
6002                         s->right = t;
6003                     }
6004                   else
6005                     constructor_pending_elts = t;
6006                 }
6007               break;
6008             }
6009           else
6010             {
6011               /* p->balance == +1; growth of left side balances the node.  */
6012               p->balance = 0;
6013               break;
6014             }
6015         }
6016       else /* r == p->right */
6017         {
6018           if (p->balance == 0)
6019             /* Growth propagation from right side.  */
6020             p->balance++;
6021           else if (p->balance > 0)
6022             {
6023               if (r->balance > 0)
6024                 {
6025                   /* R rotation.  */
6026                   p->right = r->left;
6027                   if (p->right)
6028                     p->right->parent = p;
6029                   r->left = p;
6030
6031                   p->balance = 0;
6032                   r->balance = 0;
6033
6034                   s = p->parent;
6035                   p->parent = r;
6036                   r->parent = s;
6037                   if (s)
6038                     {
6039                       if (s->left == p)
6040                         s->left = r;
6041                       else
6042                         s->right = r;
6043                     }
6044                   else
6045                     constructor_pending_elts = r;
6046                 }
6047               else /* r->balance == -1 */
6048                 {
6049                   /* RL rotation */
6050                   struct init_node *t = r->left;
6051
6052                   r->left = t->right;
6053                   if (r->left)
6054                     r->left->parent = r;
6055                   t->right = r;
6056
6057                   p->right = t->left;
6058                   if (p->right)
6059                     p->right->parent = p;
6060                   t->left = p;
6061
6062                   r->balance = (t->balance < 0);
6063                   p->balance = -(t->balance > 0);
6064                   t->balance = 0;
6065
6066                   s = p->parent;
6067                   p->parent = t;
6068                   r->parent = t;
6069                   t->parent = s;
6070                   if (s)
6071                     {
6072                       if (s->left == p)
6073                         s->left = t;
6074                       else
6075                         s->right = t;
6076                     }
6077                   else
6078                     constructor_pending_elts = t;
6079                 }
6080               break;
6081             }
6082           else
6083             {
6084               /* p->balance == -1; growth of right side balances the node.  */
6085               p->balance = 0;
6086               break;
6087             }
6088         }
6089
6090       r = p;
6091       p = p->parent;
6092     }
6093 }
6094
6095 /* Build AVL tree from a sorted chain.  */
6096
6097 static void
6098 set_nonincremental_init (void)
6099 {
6100   unsigned HOST_WIDE_INT ix;
6101   tree index, value;
6102
6103   if (TREE_CODE (constructor_type) != RECORD_TYPE
6104       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6105     return;
6106
6107   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6108     add_pending_init (index, value);
6109   constructor_elements = 0;
6110   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6111     {
6112       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6113       /* Skip any nameless bit fields at the beginning.  */
6114       while (constructor_unfilled_fields != 0
6115              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6116              && DECL_NAME (constructor_unfilled_fields) == 0)
6117         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6118
6119     }
6120   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6121     {
6122       if (TYPE_DOMAIN (constructor_type))
6123         constructor_unfilled_index
6124             = convert (bitsizetype,
6125                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6126       else
6127         constructor_unfilled_index = bitsize_zero_node;
6128     }
6129   constructor_incremental = 0;
6130 }
6131
6132 /* Build AVL tree from a string constant.  */
6133
6134 static void
6135 set_nonincremental_init_from_string (tree str)
6136 {
6137   tree value, purpose, type;
6138   HOST_WIDE_INT val[2];
6139   const char *p, *end;
6140   int byte, wchar_bytes, charwidth, bitpos;
6141
6142   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6143
6144   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6145       == TYPE_PRECISION (char_type_node))
6146     wchar_bytes = 1;
6147   else
6148     {
6149       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6150                   == TYPE_PRECISION (wchar_type_node));
6151       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6152     }
6153   charwidth = TYPE_PRECISION (char_type_node);
6154   type = TREE_TYPE (constructor_type);
6155   p = TREE_STRING_POINTER (str);
6156   end = p + TREE_STRING_LENGTH (str);
6157
6158   for (purpose = bitsize_zero_node;
6159        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6160        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6161     {
6162       if (wchar_bytes == 1)
6163         {
6164           val[1] = (unsigned char) *p++;
6165           val[0] = 0;
6166         }
6167       else
6168         {
6169           val[0] = 0;
6170           val[1] = 0;
6171           for (byte = 0; byte < wchar_bytes; byte++)
6172             {
6173               if (BYTES_BIG_ENDIAN)
6174                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6175               else
6176                 bitpos = byte * charwidth;
6177               val[bitpos < HOST_BITS_PER_WIDE_INT]
6178                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6179                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6180             }
6181         }
6182
6183       if (!TYPE_UNSIGNED (type))
6184         {
6185           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6186           if (bitpos < HOST_BITS_PER_WIDE_INT)
6187             {
6188               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6189                 {
6190                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6191                   val[0] = -1;
6192                 }
6193             }
6194           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6195             {
6196               if (val[1] < 0)
6197                 val[0] = -1;
6198             }
6199           else if (val[0] & (((HOST_WIDE_INT) 1)
6200                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6201             val[0] |= ((HOST_WIDE_INT) -1)
6202                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6203         }
6204
6205       value = build_int_cst_wide (type, val[1], val[0]);
6206       add_pending_init (purpose, value);
6207     }
6208
6209   constructor_incremental = 0;
6210 }
6211
6212 /* Return value of FIELD in pending initializer or zero if the field was
6213    not initialized yet.  */
6214
6215 static tree
6216 find_init_member (tree field)
6217 {
6218   struct init_node *p;
6219
6220   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6221     {
6222       if (constructor_incremental
6223           && tree_int_cst_lt (field, constructor_unfilled_index))
6224         set_nonincremental_init ();
6225
6226       p = constructor_pending_elts;
6227       while (p)
6228         {
6229           if (tree_int_cst_lt (field, p->purpose))
6230             p = p->left;
6231           else if (tree_int_cst_lt (p->purpose, field))
6232             p = p->right;
6233           else
6234             return p->value;
6235         }
6236     }
6237   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6238     {
6239       tree bitpos = bit_position (field);
6240
6241       if (constructor_incremental
6242           && (!constructor_unfilled_fields
6243               || tree_int_cst_lt (bitpos,
6244                                   bit_position (constructor_unfilled_fields))))
6245         set_nonincremental_init ();
6246
6247       p = constructor_pending_elts;
6248       while (p)
6249         {
6250           if (field == p->purpose)
6251             return p->value;
6252           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6253             p = p->left;
6254           else
6255             p = p->right;
6256         }
6257     }
6258   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6259     {
6260       if (!VEC_empty (constructor_elt, constructor_elements)
6261           && (VEC_last (constructor_elt, constructor_elements)->index
6262               == field))
6263         return VEC_last (constructor_elt, constructor_elements)->value;
6264     }
6265   return 0;
6266 }
6267
6268 /* "Output" the next constructor element.
6269    At top level, really output it to assembler code now.
6270    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6271    TYPE is the data type that the containing data type wants here.
6272    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6273    If VALUE is a string constant, STRICT_STRING is true if it is
6274    unparenthesized or we should not warn here for it being parenthesized.
6275    For other types of VALUE, STRICT_STRING is not used.
6276
6277    PENDING if non-nil means output pending elements that belong
6278    right after this element.  (PENDING is normally 1;
6279    it is 0 while outputting pending elements, to avoid recursion.)  */
6280
6281 static void
6282 output_init_element (tree value, bool strict_string, tree type, tree field,
6283                      int pending)
6284 {
6285   constructor_elt *celt;
6286
6287   if (type == error_mark_node || value == error_mark_node)
6288     {
6289       constructor_erroneous = 1;
6290       return;
6291     }
6292   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6293       && (TREE_CODE (value) == STRING_CST
6294           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6295       && !(TREE_CODE (value) == STRING_CST
6296            && TREE_CODE (type) == ARRAY_TYPE
6297            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6298       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6299                      TYPE_MAIN_VARIANT (type)))
6300     value = array_to_pointer_conversion (value);
6301
6302   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6303       && require_constant_value && !flag_isoc99 && pending)
6304     {
6305       /* As an extension, allow initializing objects with static storage
6306          duration with compound literals (which are then treated just as
6307          the brace enclosed list they contain).  */
6308       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6309       value = DECL_INITIAL (decl);
6310     }
6311
6312   if (value == error_mark_node)
6313     constructor_erroneous = 1;
6314   else if (!TREE_CONSTANT (value))
6315     constructor_constant = 0;
6316   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6317            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6318                 || TREE_CODE (constructor_type) == UNION_TYPE)
6319                && DECL_C_BIT_FIELD (field)
6320                && TREE_CODE (value) != INTEGER_CST))
6321     constructor_simple = 0;
6322
6323   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6324     {
6325       if (require_constant_value)
6326         {
6327           error_init ("initializer element is not constant");
6328           value = error_mark_node;
6329         }
6330       else if (require_constant_elements)
6331         pedwarn ("initializer element is not computable at load time");
6332     }
6333
6334   /* If this field is empty (and not at the end of structure),
6335      don't do anything other than checking the initializer.  */
6336   if (field
6337       && (TREE_TYPE (field) == error_mark_node
6338           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6339               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6340               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6341                   || TREE_CHAIN (field)))))
6342     return;
6343
6344   value = digest_init (type, value, strict_string, require_constant_value);
6345   if (value == error_mark_node)
6346     {
6347       constructor_erroneous = 1;
6348       return;
6349     }
6350
6351   /* If this element doesn't come next in sequence,
6352      put it on constructor_pending_elts.  */
6353   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6354       && (!constructor_incremental
6355           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6356     {
6357       if (constructor_incremental
6358           && tree_int_cst_lt (field, constructor_unfilled_index))
6359         set_nonincremental_init ();
6360
6361       add_pending_init (field, value);
6362       return;
6363     }
6364   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6365            && (!constructor_incremental
6366                || field != constructor_unfilled_fields))
6367     {
6368       /* We do this for records but not for unions.  In a union,
6369          no matter which field is specified, it can be initialized
6370          right away since it starts at the beginning of the union.  */
6371       if (constructor_incremental)
6372         {
6373           if (!constructor_unfilled_fields)
6374             set_nonincremental_init ();
6375           else
6376             {
6377               tree bitpos, unfillpos;
6378
6379               bitpos = bit_position (field);
6380               unfillpos = bit_position (constructor_unfilled_fields);
6381
6382               if (tree_int_cst_lt (bitpos, unfillpos))
6383                 set_nonincremental_init ();
6384             }
6385         }
6386
6387       add_pending_init (field, value);
6388       return;
6389     }
6390   else if (TREE_CODE (constructor_type) == UNION_TYPE
6391            && !VEC_empty (constructor_elt, constructor_elements))
6392     {
6393       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6394                                        constructor_elements)->value))
6395         warning_init ("initialized field with side-effects overwritten");
6396       else if (warn_override_init)
6397         warning_init ("initialized field overwritten");
6398
6399       /* We can have just one union field set.  */
6400       constructor_elements = 0;
6401     }
6402
6403   /* Otherwise, output this element either to
6404      constructor_elements or to the assembler file.  */
6405
6406   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6407   celt->index = field;
6408   celt->value = value;
6409
6410   /* Advance the variable that indicates sequential elements output.  */
6411   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6412     constructor_unfilled_index
6413       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6414                     bitsize_one_node);
6415   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6416     {
6417       constructor_unfilled_fields
6418         = TREE_CHAIN (constructor_unfilled_fields);
6419
6420       /* Skip any nameless bit fields.  */
6421       while (constructor_unfilled_fields != 0
6422              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6423              && DECL_NAME (constructor_unfilled_fields) == 0)
6424         constructor_unfilled_fields =
6425           TREE_CHAIN (constructor_unfilled_fields);
6426     }
6427   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6428     constructor_unfilled_fields = 0;
6429
6430   /* Now output any pending elements which have become next.  */
6431   if (pending)
6432     output_pending_init_elements (0);
6433 }
6434
6435 /* Output any pending elements which have become next.
6436    As we output elements, constructor_unfilled_{fields,index}
6437    advances, which may cause other elements to become next;
6438    if so, they too are output.
6439
6440    If ALL is 0, we return when there are
6441    no more pending elements to output now.
6442
6443    If ALL is 1, we output space as necessary so that
6444    we can output all the pending elements.  */
6445
6446 static void
6447 output_pending_init_elements (int all)
6448 {
6449   struct init_node *elt = constructor_pending_elts;
6450   tree next;
6451
6452  retry:
6453
6454   /* Look through the whole pending tree.
6455      If we find an element that should be output now,
6456      output it.  Otherwise, set NEXT to the element
6457      that comes first among those still pending.  */
6458
6459   next = 0;
6460   while (elt)
6461     {
6462       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6463         {
6464           if (tree_int_cst_equal (elt->purpose,
6465                                   constructor_unfilled_index))
6466             output_init_element (elt->value, true,
6467                                  TREE_TYPE (constructor_type),
6468                                  constructor_unfilled_index, 0);
6469           else if (tree_int_cst_lt (constructor_unfilled_index,
6470                                     elt->purpose))
6471             {
6472               /* Advance to the next smaller node.  */
6473               if (elt->left)
6474                 elt = elt->left;
6475               else
6476                 {
6477                   /* We have reached the smallest node bigger than the
6478                      current unfilled index.  Fill the space first.  */
6479                   next = elt->purpose;
6480                   break;
6481                 }
6482             }
6483           else
6484             {
6485               /* Advance to the next bigger node.  */
6486               if (elt->right)
6487                 elt = elt->right;
6488               else
6489                 {
6490                   /* We have reached the biggest node in a subtree.  Find
6491                      the parent of it, which is the next bigger node.  */
6492                   while (elt->parent && elt->parent->right == elt)
6493                     elt = elt->parent;
6494                   elt = elt->parent;
6495                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6496                                               elt->purpose))
6497                     {
6498                       next = elt->purpose;
6499                       break;
6500                     }
6501                 }
6502             }
6503         }
6504       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6505                || TREE_CODE (constructor_type) == UNION_TYPE)
6506         {
6507           tree ctor_unfilled_bitpos, elt_bitpos;
6508
6509           /* If the current record is complete we are done.  */
6510           if (constructor_unfilled_fields == 0)
6511             break;
6512
6513           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6514           elt_bitpos = bit_position (elt->purpose);
6515           /* We can't compare fields here because there might be empty
6516              fields in between.  */
6517           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6518             {
6519               constructor_unfilled_fields = elt->purpose;
6520               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6521                                    elt->purpose, 0);
6522             }
6523           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6524             {
6525               /* Advance to the next smaller node.  */
6526               if (elt->left)
6527                 elt = elt->left;
6528               else
6529                 {
6530                   /* We have reached the smallest node bigger than the
6531                      current unfilled field.  Fill the space first.  */
6532                   next = elt->purpose;
6533                   break;
6534                 }
6535             }
6536           else
6537             {
6538               /* Advance to the next bigger node.  */
6539               if (elt->right)
6540                 elt = elt->right;
6541               else
6542                 {
6543                   /* We have reached the biggest node in a subtree.  Find
6544                      the parent of it, which is the next bigger node.  */
6545                   while (elt->parent && elt->parent->right == elt)
6546                     elt = elt->parent;
6547                   elt = elt->parent;
6548                   if (elt
6549                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6550                                            bit_position (elt->purpose))))
6551                     {
6552                       next = elt->purpose;
6553                       break;
6554                     }
6555                 }
6556             }
6557         }
6558     }
6559
6560   /* Ordinarily return, but not if we want to output all
6561      and there are elements left.  */
6562   if (!(all && next != 0))
6563     return;
6564
6565   /* If it's not incremental, just skip over the gap, so that after
6566      jumping to retry we will output the next successive element.  */
6567   if (TREE_CODE (constructor_type) == RECORD_TYPE
6568       || TREE_CODE (constructor_type) == UNION_TYPE)
6569     constructor_unfilled_fields = next;
6570   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6571     constructor_unfilled_index = next;
6572
6573   /* ELT now points to the node in the pending tree with the next
6574      initializer to output.  */
6575   goto retry;
6576 }
6577 \f
6578 /* Add one non-braced element to the current constructor level.
6579    This adjusts the current position within the constructor's type.
6580    This may also start or terminate implicit levels
6581    to handle a partly-braced initializer.
6582
6583    Once this has found the correct level for the new element,
6584    it calls output_init_element.  */
6585
6586 void
6587 process_init_element (struct c_expr value)
6588 {
6589   tree orig_value = value.value;
6590   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6591   bool strict_string = value.original_code == STRING_CST;
6592
6593   designator_depth = 0;
6594   designator_erroneous = 0;
6595
6596   /* Handle superfluous braces around string cst as in
6597      char x[] = {"foo"}; */
6598   if (string_flag
6599       && constructor_type
6600       && TREE_CODE (constructor_type) == ARRAY_TYPE
6601       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6602       && integer_zerop (constructor_unfilled_index))
6603     {
6604       if (constructor_stack->replacement_value.value)
6605         error_init ("excess elements in char array initializer");
6606       constructor_stack->replacement_value = value;
6607       return;
6608     }
6609
6610   if (constructor_stack->replacement_value.value != 0)
6611     {
6612       error_init ("excess elements in struct initializer");
6613       return;
6614     }
6615
6616   /* Ignore elements of a brace group if it is entirely superfluous
6617      and has already been diagnosed.  */
6618   if (constructor_type == 0)
6619     return;
6620
6621   /* If we've exhausted any levels that didn't have braces,
6622      pop them now.  */
6623   while (constructor_stack->implicit)
6624     {
6625       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6626            || TREE_CODE (constructor_type) == UNION_TYPE)
6627           && constructor_fields == 0)
6628         process_init_element (pop_init_level (1));
6629       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6630                && (constructor_max_index == 0
6631                    || tree_int_cst_lt (constructor_max_index,
6632                                        constructor_index)))
6633         process_init_element (pop_init_level (1));
6634       else
6635         break;
6636     }
6637
6638   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6639   if (constructor_range_stack)
6640     {
6641       /* If value is a compound literal and we'll be just using its
6642          content, don't put it into a SAVE_EXPR.  */
6643       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6644           || !require_constant_value
6645           || flag_isoc99)
6646         value.value = save_expr (value.value);
6647     }
6648
6649   while (1)
6650     {
6651       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6652         {
6653           tree fieldtype;
6654           enum tree_code fieldcode;
6655
6656           if (constructor_fields == 0)
6657             {
6658               pedwarn_init ("excess elements in struct initializer");
6659               break;
6660             }
6661
6662           fieldtype = TREE_TYPE (constructor_fields);
6663           if (fieldtype != error_mark_node)
6664             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6665           fieldcode = TREE_CODE (fieldtype);
6666
6667           /* Error for non-static initialization of a flexible array member.  */
6668           if (fieldcode == ARRAY_TYPE
6669               && !require_constant_value
6670               && TYPE_SIZE (fieldtype) == NULL_TREE
6671               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6672             {
6673               error_init ("non-static initialization of a flexible array member");
6674               break;
6675             }
6676
6677           /* Accept a string constant to initialize a subarray.  */
6678           if (value.value != 0
6679               && fieldcode == ARRAY_TYPE
6680               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6681               && string_flag)
6682             value.value = orig_value;
6683           /* Otherwise, if we have come to a subaggregate,
6684              and we don't have an element of its type, push into it.  */
6685           else if (value.value != 0
6686                    && value.value != error_mark_node
6687                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6688                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6689                        || fieldcode == UNION_TYPE))
6690             {
6691               push_init_level (1);
6692               continue;
6693             }
6694
6695           if (value.value)
6696             {
6697               push_member_name (constructor_fields);
6698               output_init_element (value.value, strict_string,
6699                                    fieldtype, constructor_fields, 1);
6700               RESTORE_SPELLING_DEPTH (constructor_depth);
6701             }
6702           else
6703             /* Do the bookkeeping for an element that was
6704                directly output as a constructor.  */
6705             {
6706               /* For a record, keep track of end position of last field.  */
6707               if (DECL_SIZE (constructor_fields))
6708                 constructor_bit_index
6709                   = size_binop (PLUS_EXPR,
6710                                 bit_position (constructor_fields),
6711                                 DECL_SIZE (constructor_fields));
6712
6713               /* If the current field was the first one not yet written out,
6714                  it isn't now, so update.  */
6715               if (constructor_unfilled_fields == constructor_fields)
6716                 {
6717                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6718                   /* Skip any nameless bit fields.  */
6719                   while (constructor_unfilled_fields != 0
6720                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6721                          && DECL_NAME (constructor_unfilled_fields) == 0)
6722                     constructor_unfilled_fields =
6723                       TREE_CHAIN (constructor_unfilled_fields);
6724                 }
6725             }
6726
6727           constructor_fields = TREE_CHAIN (constructor_fields);
6728           /* Skip any nameless bit fields at the beginning.  */
6729           while (constructor_fields != 0
6730                  && DECL_C_BIT_FIELD (constructor_fields)
6731                  && DECL_NAME (constructor_fields) == 0)
6732             constructor_fields = TREE_CHAIN (constructor_fields);
6733         }
6734       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6735         {
6736           tree fieldtype;
6737           enum tree_code fieldcode;
6738
6739           if (constructor_fields == 0)
6740             {
6741               pedwarn_init ("excess elements in union initializer");
6742               break;
6743             }
6744
6745           fieldtype = TREE_TYPE (constructor_fields);
6746           if (fieldtype != error_mark_node)
6747             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6748           fieldcode = TREE_CODE (fieldtype);
6749
6750           /* Warn that traditional C rejects initialization of unions.
6751              We skip the warning if the value is zero.  This is done
6752              under the assumption that the zero initializer in user
6753              code appears conditioned on e.g. __STDC__ to avoid
6754              "missing initializer" warnings and relies on default
6755              initialization to zero in the traditional C case.
6756              We also skip the warning if the initializer is designated,
6757              again on the assumption that this must be conditional on
6758              __STDC__ anyway (and we've already complained about the
6759              member-designator already).  */
6760           if (!in_system_header && !constructor_designated
6761               && !(value.value && (integer_zerop (value.value)
6762                                    || real_zerop (value.value))))
6763             warning (OPT_Wtraditional, "traditional C rejects initialization "
6764                      "of unions");
6765
6766           /* Accept a string constant to initialize a subarray.  */
6767           if (value.value != 0
6768               && fieldcode == ARRAY_TYPE
6769               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6770               && string_flag)
6771             value.value = orig_value;
6772           /* Otherwise, if we have come to a subaggregate,
6773              and we don't have an element of its type, push into it.  */
6774           else if (value.value != 0
6775                    && value.value != error_mark_node
6776                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6777                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6778                        || fieldcode == UNION_TYPE))
6779             {
6780               push_init_level (1);
6781               continue;
6782             }
6783
6784           if (value.value)
6785             {
6786               push_member_name (constructor_fields);
6787               output_init_element (value.value, strict_string,
6788                                    fieldtype, constructor_fields, 1);
6789               RESTORE_SPELLING_DEPTH (constructor_depth);
6790             }
6791           else
6792             /* Do the bookkeeping for an element that was
6793                directly output as a constructor.  */
6794             {
6795               constructor_bit_index = DECL_SIZE (constructor_fields);
6796               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6797             }
6798
6799           constructor_fields = 0;
6800         }
6801       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6802         {
6803           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6804           enum tree_code eltcode = TREE_CODE (elttype);
6805
6806           /* Accept a string constant to initialize a subarray.  */
6807           if (value.value != 0
6808               && eltcode == ARRAY_TYPE
6809               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6810               && string_flag)
6811             value.value = orig_value;
6812           /* Otherwise, if we have come to a subaggregate,
6813              and we don't have an element of its type, push into it.  */
6814           else if (value.value != 0
6815                    && value.value != error_mark_node
6816                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6817                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6818                        || eltcode == UNION_TYPE))
6819             {
6820               push_init_level (1);
6821               continue;
6822             }
6823
6824           if (constructor_max_index != 0
6825               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6826                   || integer_all_onesp (constructor_max_index)))
6827             {
6828               pedwarn_init ("excess elements in array initializer");
6829               break;
6830             }
6831
6832           /* Now output the actual element.  */
6833           if (value.value)
6834             {
6835               push_array_bounds (tree_low_cst (constructor_index, 1));
6836               output_init_element (value.value, strict_string,
6837                                    elttype, constructor_index, 1);
6838               RESTORE_SPELLING_DEPTH (constructor_depth);
6839             }
6840
6841           constructor_index
6842             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6843
6844           if (!value.value)
6845             /* If we are doing the bookkeeping for an element that was
6846                directly output as a constructor, we must update
6847                constructor_unfilled_index.  */
6848             constructor_unfilled_index = constructor_index;
6849         }
6850       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6851         {
6852           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6853
6854          /* Do a basic check of initializer size.  Note that vectors
6855             always have a fixed size derived from their type.  */
6856           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6857             {
6858               pedwarn_init ("excess elements in vector initializer");
6859               break;
6860             }
6861
6862           /* Now output the actual element.  */
6863           if (value.value)
6864             output_init_element (value.value, strict_string,
6865                                  elttype, constructor_index, 1);
6866
6867           constructor_index
6868             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6869
6870           if (!value.value)
6871             /* If we are doing the bookkeeping for an element that was
6872                directly output as a constructor, we must update
6873                constructor_unfilled_index.  */
6874             constructor_unfilled_index = constructor_index;
6875         }
6876
6877       /* Handle the sole element allowed in a braced initializer
6878          for a scalar variable.  */
6879       else if (constructor_type != error_mark_node
6880                && constructor_fields == 0)
6881         {
6882           pedwarn_init ("excess elements in scalar initializer");
6883           break;
6884         }
6885       else
6886         {
6887           if (value.value)
6888             output_init_element (value.value, strict_string,
6889                                  constructor_type, NULL_TREE, 1);
6890           constructor_fields = 0;
6891         }
6892
6893       /* Handle range initializers either at this level or anywhere higher
6894          in the designator stack.  */
6895       if (constructor_range_stack)
6896         {
6897           struct constructor_range_stack *p, *range_stack;
6898           int finish = 0;
6899
6900           range_stack = constructor_range_stack;
6901           constructor_range_stack = 0;
6902           while (constructor_stack != range_stack->stack)
6903             {
6904               gcc_assert (constructor_stack->implicit);
6905               process_init_element (pop_init_level (1));
6906             }
6907           for (p = range_stack;
6908                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6909                p = p->prev)
6910             {
6911               gcc_assert (constructor_stack->implicit);
6912               process_init_element (pop_init_level (1));
6913             }
6914
6915           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6916           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6917             finish = 1;
6918
6919           while (1)
6920             {
6921               constructor_index = p->index;
6922               constructor_fields = p->fields;
6923               if (finish && p->range_end && p->index == p->range_start)
6924                 {
6925                   finish = 0;
6926                   p->prev = 0;
6927                 }
6928               p = p->next;
6929               if (!p)
6930                 break;
6931               push_init_level (2);
6932               p->stack = constructor_stack;
6933               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6934                 p->index = p->range_start;
6935             }
6936
6937           if (!finish)
6938             constructor_range_stack = range_stack;
6939           continue;
6940         }
6941
6942       break;
6943     }
6944
6945   constructor_range_stack = 0;
6946 }
6947 \f
6948 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6949    (guaranteed to be 'volatile' or null) and ARGS (represented using
6950    an ASM_EXPR node).  */
6951 tree
6952 build_asm_stmt (tree cv_qualifier, tree args)
6953 {
6954   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6955     ASM_VOLATILE_P (args) = 1;
6956   return add_stmt (args);
6957 }
6958
6959 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6960    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6961    SIMPLE indicates whether there was anything at all after the
6962    string in the asm expression -- asm("blah") and asm("blah" : )
6963    are subtly different.  We use a ASM_EXPR node to represent this.  */
6964 tree
6965 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6966                 bool simple)
6967 {
6968   tree tail;
6969   tree args;
6970   int i;
6971   const char *constraint;
6972   const char **oconstraints;
6973   bool allows_mem, allows_reg, is_inout;
6974   int ninputs, noutputs;
6975
6976   ninputs = list_length (inputs);
6977   noutputs = list_length (outputs);
6978   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6979
6980   string = resolve_asm_operand_names (string, outputs, inputs);
6981
6982   /* Remove output conversions that change the type but not the mode.  */
6983   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6984     {
6985       tree output = TREE_VALUE (tail);
6986
6987       /* ??? Really, this should not be here.  Users should be using a
6988          proper lvalue, dammit.  But there's a long history of using casts
6989          in the output operands.  In cases like longlong.h, this becomes a
6990          primitive form of typechecking -- if the cast can be removed, then
6991          the output operand had a type of the proper width; otherwise we'll
6992          get an error.  Gross, but ...  */
6993       STRIP_NOPS (output);
6994
6995       if (!lvalue_or_else (output, lv_asm))
6996         output = error_mark_node;
6997
6998       if (output != error_mark_node
6999           && (TREE_READONLY (output)
7000               || TYPE_READONLY (TREE_TYPE (output))
7001               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7002                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7003                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7004         readonly_error (output, lv_asm);
7005
7006       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7007       oconstraints[i] = constraint;
7008
7009       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7010                                    &allows_mem, &allows_reg, &is_inout))
7011         {
7012           /* If the operand is going to end up in memory,
7013              mark it addressable.  */
7014           if (!allows_reg && !c_mark_addressable (output))
7015             output = error_mark_node;
7016         }
7017       else
7018         output = error_mark_node;
7019
7020       TREE_VALUE (tail) = output;
7021     }
7022
7023   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7024     {
7025       tree input;
7026
7027       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7028       input = TREE_VALUE (tail);
7029
7030       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7031                                   oconstraints, &allows_mem, &allows_reg))
7032         {
7033           /* If the operand is going to end up in memory,
7034              mark it addressable.  */
7035           if (!allows_reg && allows_mem)
7036             {
7037               /* Strip the nops as we allow this case.  FIXME, this really
7038                  should be rejected or made deprecated.  */
7039               STRIP_NOPS (input);
7040               if (!c_mark_addressable (input))
7041                 input = error_mark_node;
7042           }
7043         }
7044       else
7045         input = error_mark_node;
7046
7047       TREE_VALUE (tail) = input;
7048     }
7049
7050   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7051
7052   /* asm statements without outputs, including simple ones, are treated
7053      as volatile.  */
7054   ASM_INPUT_P (args) = simple;
7055   ASM_VOLATILE_P (args) = (noutputs == 0);
7056
7057   return args;
7058 }
7059 \f
7060 /* Generate a goto statement to LABEL.  */
7061
7062 tree
7063 c_finish_goto_label (tree label)
7064 {
7065   tree decl = lookup_label (label);
7066   if (!decl)
7067     return NULL_TREE;
7068
7069   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7070     {
7071       error ("jump into statement expression");
7072       return NULL_TREE;
7073     }
7074
7075   if (C_DECL_UNJUMPABLE_VM (decl))
7076     {
7077       error ("jump into scope of identifier with variably modified type");
7078       return NULL_TREE;
7079     }
7080
7081   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7082     {
7083       /* No jump from outside this statement expression context, so
7084          record that there is a jump from within this context.  */
7085       struct c_label_list *nlist;
7086       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7087       nlist->next = label_context_stack_se->labels_used;
7088       nlist->label = decl;
7089       label_context_stack_se->labels_used = nlist;
7090     }
7091
7092   if (!C_DECL_UNDEFINABLE_VM (decl))
7093     {
7094       /* No jump from outside this context context of identifiers with
7095          variably modified type, so record that there is a jump from
7096          within this context.  */
7097       struct c_label_list *nlist;
7098       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7099       nlist->next = label_context_stack_vm->labels_used;
7100       nlist->label = decl;
7101       label_context_stack_vm->labels_used = nlist;
7102     }
7103
7104   TREE_USED (decl) = 1;
7105   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7106 }
7107
7108 /* Generate a computed goto statement to EXPR.  */
7109
7110 tree
7111 c_finish_goto_ptr (tree expr)
7112 {
7113   if (pedantic)
7114     pedwarn ("ISO C forbids %<goto *expr;%>");
7115   expr = convert (ptr_type_node, expr);
7116   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7117 }
7118
7119 /* Generate a C `return' statement.  RETVAL is the expression for what
7120    to return, or a null pointer for `return;' with no value.  */
7121
7122 tree
7123 c_finish_return (tree retval)
7124 {
7125   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7126   bool no_warning = false;
7127
7128   if (TREE_THIS_VOLATILE (current_function_decl))
7129     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7130
7131   if (!retval)
7132     {
7133       current_function_returns_null = 1;
7134       if ((warn_return_type || flag_isoc99)
7135           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7136         {
7137           pedwarn_c99 ("%<return%> with no value, in "
7138                        "function returning non-void");
7139           no_warning = true;
7140         }
7141     }
7142   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7143     {
7144       current_function_returns_null = 1;
7145       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7146         pedwarn ("%<return%> with a value, in function returning void");
7147       else if (pedantic)
7148         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7149     }
7150   else
7151     {
7152       tree t = convert_for_assignment (valtype, retval, ic_return,
7153                                        NULL_TREE, NULL_TREE, 0);
7154       tree res = DECL_RESULT (current_function_decl);
7155       tree inner;
7156
7157       current_function_returns_value = 1;
7158       if (t == error_mark_node)
7159         return NULL_TREE;
7160
7161       inner = t = convert (TREE_TYPE (res), t);
7162
7163       /* Strip any conversions, additions, and subtractions, and see if
7164          we are returning the address of a local variable.  Warn if so.  */
7165       while (1)
7166         {
7167           switch (TREE_CODE (inner))
7168             {
7169             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
7170             case PLUS_EXPR:
7171             case POINTER_PLUS_EXPR:
7172               inner = TREE_OPERAND (inner, 0);
7173               continue;
7174
7175             case MINUS_EXPR:
7176               /* If the second operand of the MINUS_EXPR has a pointer
7177                  type (or is converted from it), this may be valid, so
7178                  don't give a warning.  */
7179               {
7180                 tree op1 = TREE_OPERAND (inner, 1);
7181
7182                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7183                        && (TREE_CODE (op1) == NOP_EXPR
7184                            || TREE_CODE (op1) == NON_LVALUE_EXPR
7185                            || TREE_CODE (op1) == CONVERT_EXPR))
7186                   op1 = TREE_OPERAND (op1, 0);
7187
7188                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7189                   break;
7190
7191                 inner = TREE_OPERAND (inner, 0);
7192                 continue;
7193               }
7194
7195             case ADDR_EXPR:
7196               inner = TREE_OPERAND (inner, 0);
7197
7198               while (REFERENCE_CLASS_P (inner)
7199                      && TREE_CODE (inner) != INDIRECT_REF)
7200                 inner = TREE_OPERAND (inner, 0);
7201
7202               if (DECL_P (inner)
7203                   && !DECL_EXTERNAL (inner)
7204                   && !TREE_STATIC (inner)
7205                   && DECL_CONTEXT (inner) == current_function_decl)
7206                 warning (0, "function returns address of local variable");
7207               break;
7208
7209             default:
7210               break;
7211             }
7212
7213           break;
7214         }
7215
7216       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7217     }
7218
7219   ret_stmt = build_stmt (RETURN_EXPR, retval);
7220   TREE_NO_WARNING (ret_stmt) |= no_warning;
7221   return add_stmt (ret_stmt);
7222 }
7223 \f
7224 struct c_switch {
7225   /* The SWITCH_EXPR being built.  */
7226   tree switch_expr;
7227
7228   /* The original type of the testing expression, i.e. before the
7229      default conversion is applied.  */
7230   tree orig_type;
7231
7232   /* A splay-tree mapping the low element of a case range to the high
7233      element, or NULL_TREE if there is no high element.  Used to
7234      determine whether or not a new case label duplicates an old case
7235      label.  We need a tree, rather than simply a hash table, because
7236      of the GNU case range extension.  */
7237   splay_tree cases;
7238
7239   /* Number of nested statement expressions within this switch
7240      statement; if nonzero, case and default labels may not
7241      appear.  */
7242   unsigned int blocked_stmt_expr;
7243
7244   /* Scope of outermost declarations of identifiers with variably
7245      modified type within this switch statement; if nonzero, case and
7246      default labels may not appear.  */
7247   unsigned int blocked_vm;
7248
7249   /* The next node on the stack.  */
7250   struct c_switch *next;
7251 };
7252
7253 /* A stack of the currently active switch statements.  The innermost
7254    switch statement is on the top of the stack.  There is no need to
7255    mark the stack for garbage collection because it is only active
7256    during the processing of the body of a function, and we never
7257    collect at that point.  */
7258
7259 struct c_switch *c_switch_stack;
7260
7261 /* Start a C switch statement, testing expression EXP.  Return the new
7262    SWITCH_EXPR.  */
7263
7264 tree
7265 c_start_case (tree exp)
7266 {
7267   tree orig_type = error_mark_node;
7268   struct c_switch *cs;
7269
7270   if (exp != error_mark_node)
7271     {
7272       orig_type = TREE_TYPE (exp);
7273
7274       if (!INTEGRAL_TYPE_P (orig_type))
7275         {
7276           if (orig_type != error_mark_node)
7277             {
7278               error ("switch quantity not an integer");
7279               orig_type = error_mark_node;
7280             }
7281           exp = integer_zero_node;
7282         }
7283       else
7284         {
7285           tree type = TYPE_MAIN_VARIANT (orig_type);
7286
7287           if (!in_system_header
7288               && (type == long_integer_type_node
7289                   || type == long_unsigned_type_node))
7290             warning (OPT_Wtraditional, "%<long%> switch expression not "
7291                      "converted to %<int%> in ISO C");
7292
7293           exp = default_conversion (exp);
7294         }
7295     }
7296
7297   /* Add this new SWITCH_EXPR to the stack.  */
7298   cs = XNEW (struct c_switch);
7299   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7300   cs->orig_type = orig_type;
7301   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7302   cs->blocked_stmt_expr = 0;
7303   cs->blocked_vm = 0;
7304   cs->next = c_switch_stack;
7305   c_switch_stack = cs;
7306
7307   return add_stmt (cs->switch_expr);
7308 }
7309
7310 /* Process a case label.  */
7311
7312 tree
7313 do_case (tree low_value, tree high_value)
7314 {
7315   tree label = NULL_TREE;
7316
7317   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7318       && !c_switch_stack->blocked_vm)
7319     {
7320       label = c_add_case_label (c_switch_stack->cases,
7321                                 SWITCH_COND (c_switch_stack->switch_expr),
7322                                 c_switch_stack->orig_type,
7323                                 low_value, high_value);
7324       if (label == error_mark_node)
7325         label = NULL_TREE;
7326     }
7327   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7328     {
7329       if (low_value)
7330         error ("case label in statement expression not containing "
7331                "enclosing switch statement");
7332       else
7333         error ("%<default%> label in statement expression not containing "
7334                "enclosing switch statement");
7335     }
7336   else if (c_switch_stack && c_switch_stack->blocked_vm)
7337     {
7338       if (low_value)
7339         error ("case label in scope of identifier with variably modified "
7340                "type not containing enclosing switch statement");
7341       else
7342         error ("%<default%> label in scope of identifier with variably "
7343                "modified type not containing enclosing switch statement");
7344     }
7345   else if (low_value)
7346     error ("case label not within a switch statement");
7347   else
7348     error ("%<default%> label not within a switch statement");
7349
7350   return label;
7351 }
7352
7353 /* Finish the switch statement.  */
7354
7355 void
7356 c_finish_case (tree body)
7357 {
7358   struct c_switch *cs = c_switch_stack;
7359   location_t switch_location;
7360
7361   SWITCH_BODY (cs->switch_expr) = body;
7362
7363   /* We must not be within a statement expression nested in the switch
7364      at this point; we might, however, be within the scope of an
7365      identifier with variably modified type nested in the switch.  */
7366   gcc_assert (!cs->blocked_stmt_expr);
7367
7368   /* Emit warnings as needed.  */
7369   if (EXPR_HAS_LOCATION (cs->switch_expr))
7370     switch_location = EXPR_LOCATION (cs->switch_expr);
7371   else
7372     switch_location = input_location;
7373   c_do_switch_warnings (cs->cases, switch_location,
7374                         TREE_TYPE (cs->switch_expr),
7375                         SWITCH_COND (cs->switch_expr));
7376
7377   /* Pop the stack.  */
7378   c_switch_stack = cs->next;
7379   splay_tree_delete (cs->cases);
7380   XDELETE (cs);
7381 }
7382 \f
7383 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7384    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7385    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7386    statement, and was not surrounded with parenthesis.  */
7387
7388 void
7389 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7390                   tree else_block, bool nested_if)
7391 {
7392   tree stmt;
7393
7394   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7395   if (warn_parentheses && nested_if && else_block == NULL)
7396     {
7397       tree inner_if = then_block;
7398
7399       /* We know from the grammar productions that there is an IF nested
7400          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7401          it might not be exactly THEN_BLOCK, but should be the last
7402          non-container statement within.  */
7403       while (1)
7404         switch (TREE_CODE (inner_if))
7405           {
7406           case COND_EXPR:
7407             goto found;
7408           case BIND_EXPR:
7409             inner_if = BIND_EXPR_BODY (inner_if);
7410             break;
7411           case STATEMENT_LIST:
7412             inner_if = expr_last (then_block);
7413             break;
7414           case TRY_FINALLY_EXPR:
7415           case TRY_CATCH_EXPR:
7416             inner_if = TREE_OPERAND (inner_if, 0);
7417             break;
7418           default:
7419             gcc_unreachable ();
7420           }
7421     found:
7422
7423       if (COND_EXPR_ELSE (inner_if))
7424          warning (OPT_Wparentheses,
7425                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7426                   &if_locus);
7427     }
7428
7429   empty_if_body_warning (then_block, else_block);
7430
7431   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7432   SET_EXPR_LOCATION (stmt, if_locus);
7433   add_stmt (stmt);
7434 }
7435
7436 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7437    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7438    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7439    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7440    the continue label.  Everything is allowed to be NULL.  */
7441
7442 void
7443 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7444                tree blab, tree clab, bool cond_is_first)
7445 {
7446   tree entry = NULL, exit = NULL, t;
7447
7448   /* If the condition is zero don't generate a loop construct.  */
7449   if (cond && integer_zerop (cond))
7450     {
7451       if (cond_is_first)
7452         {
7453           t = build_and_jump (&blab);
7454           SET_EXPR_LOCATION (t, start_locus);
7455           add_stmt (t);
7456         }
7457     }
7458   else
7459     {
7460       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7461
7462       /* If we have an exit condition, then we build an IF with gotos either
7463          out of the loop, or to the top of it.  If there's no exit condition,
7464          then we just build a jump back to the top.  */
7465       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7466
7467       if (cond && !integer_nonzerop (cond))
7468         {
7469           /* Canonicalize the loop condition to the end.  This means
7470              generating a branch to the loop condition.  Reuse the
7471              continue label, if possible.  */
7472           if (cond_is_first)
7473             {
7474               if (incr || !clab)
7475                 {
7476                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7477                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7478                 }
7479               else
7480                 t = build1 (GOTO_EXPR, void_type_node, clab);
7481               SET_EXPR_LOCATION (t, start_locus);
7482               add_stmt (t);
7483             }
7484
7485           t = build_and_jump (&blab);
7486           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7487           if (cond_is_first)
7488             SET_EXPR_LOCATION (exit, start_locus);
7489           else
7490             SET_EXPR_LOCATION (exit, input_location);
7491         }
7492
7493       add_stmt (top);
7494     }
7495
7496   if (body)
7497     add_stmt (body);
7498   if (clab)
7499     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7500   if (incr)
7501     add_stmt (incr);
7502   if (entry)
7503     add_stmt (entry);
7504   if (exit)
7505     add_stmt (exit);
7506   if (blab)
7507     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7508 }
7509
7510 tree
7511 c_finish_bc_stmt (tree *label_p, bool is_break)
7512 {
7513   bool skip;
7514   tree label = *label_p;
7515
7516   /* In switch statements break is sometimes stylistically used after
7517      a return statement.  This can lead to spurious warnings about
7518      control reaching the end of a non-void function when it is
7519      inlined.  Note that we are calling block_may_fallthru with
7520      language specific tree nodes; this works because
7521      block_may_fallthru returns true when given something it does not
7522      understand.  */
7523   skip = !block_may_fallthru (cur_stmt_list);
7524
7525   if (!label)
7526     {
7527       if (!skip)
7528         *label_p = label = create_artificial_label ();
7529     }
7530   else if (TREE_CODE (label) == LABEL_DECL)
7531     ;
7532   else switch (TREE_INT_CST_LOW (label))
7533     {
7534     case 0:
7535       if (is_break)
7536         error ("break statement not within loop or switch");
7537       else
7538         error ("continue statement not within a loop");
7539       return NULL_TREE;
7540
7541     case 1:
7542       gcc_assert (is_break);
7543       error ("break statement used with OpenMP for loop");
7544       return NULL_TREE;
7545
7546     default:
7547       gcc_unreachable ();
7548     }
7549
7550   if (skip)
7551     return NULL_TREE;
7552
7553   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7554 }
7555
7556 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7557
7558 static void
7559 emit_side_effect_warnings (tree expr)
7560 {
7561   if (expr == error_mark_node)
7562     ;
7563   else if (!TREE_SIDE_EFFECTS (expr))
7564     {
7565       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7566         warning (OPT_Wunused_value, "%Hstatement with no effect",
7567                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7568     }
7569   else
7570     warn_if_unused_value (expr, input_location);
7571 }
7572
7573 /* Process an expression as if it were a complete statement.  Emit
7574    diagnostics, but do not call ADD_STMT.  */
7575
7576 tree
7577 c_process_expr_stmt (tree expr)
7578 {
7579   if (!expr)
7580     return NULL_TREE;
7581
7582   if (warn_sequence_point)
7583     verify_sequence_points (expr);
7584
7585   if (TREE_TYPE (expr) != error_mark_node
7586       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7587       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7588     error ("expression statement has incomplete type");
7589
7590   /* If we're not processing a statement expression, warn about unused values.
7591      Warnings for statement expressions will be emitted later, once we figure
7592      out which is the result.  */
7593   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7594       && warn_unused_value)
7595     emit_side_effect_warnings (expr);
7596
7597   /* If the expression is not of a type to which we cannot assign a line
7598      number, wrap the thing in a no-op NOP_EXPR.  */
7599   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7600     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7601
7602   if (CAN_HAVE_LOCATION_P (expr))
7603     SET_EXPR_LOCATION (expr, input_location);
7604
7605   return expr;
7606 }
7607
7608 /* Emit an expression as a statement.  */
7609
7610 tree
7611 c_finish_expr_stmt (tree expr)
7612 {
7613   if (expr)
7614     return add_stmt (c_process_expr_stmt (expr));
7615   else
7616     return NULL;
7617 }
7618
7619 /* Do the opposite and emit a statement as an expression.  To begin,
7620    create a new binding level and return it.  */
7621
7622 tree
7623 c_begin_stmt_expr (void)
7624 {
7625   tree ret;
7626   struct c_label_context_se *nstack;
7627   struct c_label_list *glist;
7628
7629   /* We must force a BLOCK for this level so that, if it is not expanded
7630      later, there is a way to turn off the entire subtree of blocks that
7631      are contained in it.  */
7632   keep_next_level ();
7633   ret = c_begin_compound_stmt (true);
7634   if (c_switch_stack)
7635     {
7636       c_switch_stack->blocked_stmt_expr++;
7637       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7638     }
7639   for (glist = label_context_stack_se->labels_used;
7640        glist != NULL;
7641        glist = glist->next)
7642     {
7643       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7644     }
7645   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7646   nstack->labels_def = NULL;
7647   nstack->labels_used = NULL;
7648   nstack->next = label_context_stack_se;
7649   label_context_stack_se = nstack;
7650
7651   /* Mark the current statement list as belonging to a statement list.  */
7652   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7653
7654   return ret;
7655 }
7656
7657 tree
7658 c_finish_stmt_expr (tree body)
7659 {
7660   tree last, type, tmp, val;
7661   tree *last_p;
7662   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7663
7664   body = c_end_compound_stmt (body, true);
7665   if (c_switch_stack)
7666     {
7667       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7668       c_switch_stack->blocked_stmt_expr--;
7669     }
7670   /* It is no longer possible to jump to labels defined within this
7671      statement expression.  */
7672   for (dlist = label_context_stack_se->labels_def;
7673        dlist != NULL;
7674        dlist = dlist->next)
7675     {
7676       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7677     }
7678   /* It is again possible to define labels with a goto just outside
7679      this statement expression.  */
7680   for (glist = label_context_stack_se->next->labels_used;
7681        glist != NULL;
7682        glist = glist->next)
7683     {
7684       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7685       glist_prev = glist;
7686     }
7687   if (glist_prev != NULL)
7688     glist_prev->next = label_context_stack_se->labels_used;
7689   else
7690     label_context_stack_se->next->labels_used
7691       = label_context_stack_se->labels_used;
7692   label_context_stack_se = label_context_stack_se->next;
7693
7694   /* Locate the last statement in BODY.  See c_end_compound_stmt
7695      about always returning a BIND_EXPR.  */
7696   last_p = &BIND_EXPR_BODY (body);
7697   last = BIND_EXPR_BODY (body);
7698
7699  continue_searching:
7700   if (TREE_CODE (last) == STATEMENT_LIST)
7701     {
7702       tree_stmt_iterator i;
7703
7704       /* This can happen with degenerate cases like ({ }).  No value.  */
7705       if (!TREE_SIDE_EFFECTS (last))
7706         return body;
7707
7708       /* If we're supposed to generate side effects warnings, process
7709          all of the statements except the last.  */
7710       if (warn_unused_value)
7711         {
7712           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7713             emit_side_effect_warnings (tsi_stmt (i));
7714         }
7715       else
7716         i = tsi_last (last);
7717       last_p = tsi_stmt_ptr (i);
7718       last = *last_p;
7719     }
7720
7721   /* If the end of the list is exception related, then the list was split
7722      by a call to push_cleanup.  Continue searching.  */
7723   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7724       || TREE_CODE (last) == TRY_CATCH_EXPR)
7725     {
7726       last_p = &TREE_OPERAND (last, 0);
7727       last = *last_p;
7728       goto continue_searching;
7729     }
7730
7731   /* In the case that the BIND_EXPR is not necessary, return the
7732      expression out from inside it.  */
7733   if (last == error_mark_node
7734       || (last == BIND_EXPR_BODY (body)
7735           && BIND_EXPR_VARS (body) == NULL))
7736     {
7737       /* Do not warn if the return value of a statement expression is
7738          unused.  */
7739       if (CAN_HAVE_LOCATION_P (last))
7740         TREE_NO_WARNING (last) = 1;
7741       return last;
7742     }
7743
7744   /* Extract the type of said expression.  */
7745   type = TREE_TYPE (last);
7746
7747   /* If we're not returning a value at all, then the BIND_EXPR that
7748      we already have is a fine expression to return.  */
7749   if (!type || VOID_TYPE_P (type))
7750     return body;
7751
7752   /* Now that we've located the expression containing the value, it seems
7753      silly to make voidify_wrapper_expr repeat the process.  Create a
7754      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7755   tmp = create_tmp_var_raw (type, NULL);
7756
7757   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7758      tree_expr_nonnegative_p giving up immediately.  */
7759   val = last;
7760   if (TREE_CODE (val) == NOP_EXPR
7761       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7762     val = TREE_OPERAND (val, 0);
7763
7764   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7765   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7766
7767   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7768 }
7769
7770 /* Begin the scope of an identifier of variably modified type, scope
7771    number SCOPE.  Jumping from outside this scope to inside it is not
7772    permitted.  */
7773
7774 void
7775 c_begin_vm_scope (unsigned int scope)
7776 {
7777   struct c_label_context_vm *nstack;
7778   struct c_label_list *glist;
7779
7780   gcc_assert (scope > 0);
7781
7782   /* At file_scope, we don't have to do any processing.  */
7783   if (label_context_stack_vm == NULL)
7784     return;
7785
7786   if (c_switch_stack && !c_switch_stack->blocked_vm)
7787     c_switch_stack->blocked_vm = scope;
7788   for (glist = label_context_stack_vm->labels_used;
7789        glist != NULL;
7790        glist = glist->next)
7791     {
7792       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7793     }
7794   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7795   nstack->labels_def = NULL;
7796   nstack->labels_used = NULL;
7797   nstack->scope = scope;
7798   nstack->next = label_context_stack_vm;
7799   label_context_stack_vm = nstack;
7800 }
7801
7802 /* End a scope which may contain identifiers of variably modified
7803    type, scope number SCOPE.  */
7804
7805 void
7806 c_end_vm_scope (unsigned int scope)
7807 {
7808   if (label_context_stack_vm == NULL)
7809     return;
7810   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7811     c_switch_stack->blocked_vm = 0;
7812   /* We may have a number of nested scopes of identifiers with
7813      variably modified type, all at this depth.  Pop each in turn.  */
7814   while (label_context_stack_vm->scope == scope)
7815     {
7816       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7817
7818       /* It is no longer possible to jump to labels defined within this
7819          scope.  */
7820       for (dlist = label_context_stack_vm->labels_def;
7821            dlist != NULL;
7822            dlist = dlist->next)
7823         {
7824           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7825         }
7826       /* It is again possible to define labels with a goto just outside
7827          this scope.  */
7828       for (glist = label_context_stack_vm->next->labels_used;
7829            glist != NULL;
7830            glist = glist->next)
7831         {
7832           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7833           glist_prev = glist;
7834         }
7835       if (glist_prev != NULL)
7836         glist_prev->next = label_context_stack_vm->labels_used;
7837       else
7838         label_context_stack_vm->next->labels_used
7839           = label_context_stack_vm->labels_used;
7840       label_context_stack_vm = label_context_stack_vm->next;
7841     }
7842 }
7843 \f
7844 /* Begin and end compound statements.  This is as simple as pushing
7845    and popping new statement lists from the tree.  */
7846
7847 tree
7848 c_begin_compound_stmt (bool do_scope)
7849 {
7850   tree stmt = push_stmt_list ();
7851   if (do_scope)
7852     push_scope ();
7853   return stmt;
7854 }
7855
7856 tree
7857 c_end_compound_stmt (tree stmt, bool do_scope)
7858 {
7859   tree block = NULL;
7860
7861   if (do_scope)
7862     {
7863       if (c_dialect_objc ())
7864         objc_clear_super_receiver ();
7865       block = pop_scope ();
7866     }
7867
7868   stmt = pop_stmt_list (stmt);
7869   stmt = c_build_bind_expr (block, stmt);
7870
7871   /* If this compound statement is nested immediately inside a statement
7872      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7873      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7874      STATEMENT_LISTs merge, and thus we can lose track of what statement
7875      was really last.  */
7876   if (cur_stmt_list
7877       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7878       && TREE_CODE (stmt) != BIND_EXPR)
7879     {
7880       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7881       TREE_SIDE_EFFECTS (stmt) = 1;
7882     }
7883
7884   return stmt;
7885 }
7886
7887 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7888    when the current scope is exited.  EH_ONLY is true when this is not
7889    meant to apply to normal control flow transfer.  */
7890
7891 void
7892 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7893 {
7894   enum tree_code code;
7895   tree stmt, list;
7896   bool stmt_expr;
7897
7898   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7899   stmt = build_stmt (code, NULL, cleanup);
7900   add_stmt (stmt);
7901   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7902   list = push_stmt_list ();
7903   TREE_OPERAND (stmt, 0) = list;
7904   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7905 }
7906 \f
7907 /* Build a binary-operation expression without default conversions.
7908    CODE is the kind of expression to build.
7909    This function differs from `build' in several ways:
7910    the data type of the result is computed and recorded in it,
7911    warnings are generated if arg data types are invalid,
7912    special handling for addition and subtraction of pointers is known,
7913    and some optimization is done (operations on narrow ints
7914    are done in the narrower type when that gives the same result).
7915    Constant folding is also done before the result is returned.
7916
7917    Note that the operands will never have enumeral types, or function
7918    or array types, because either they will have the default conversions
7919    performed or they have both just been converted to some other type in which
7920    the arithmetic is to be done.  */
7921
7922 tree
7923 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7924                  int convert_p)
7925 {
7926   tree type0, type1;
7927   enum tree_code code0, code1;
7928   tree op0, op1;
7929   const char *invalid_op_diag;
7930
7931   /* Expression code to give to the expression when it is built.
7932      Normally this is CODE, which is what the caller asked for,
7933      but in some special cases we change it.  */
7934   enum tree_code resultcode = code;
7935
7936   /* Data type in which the computation is to be performed.
7937      In the simplest cases this is the common type of the arguments.  */
7938   tree result_type = NULL;
7939
7940   /* Nonzero means operands have already been type-converted
7941      in whatever way is necessary.
7942      Zero means they need to be converted to RESULT_TYPE.  */
7943   int converted = 0;
7944
7945   /* Nonzero means create the expression with this type, rather than
7946      RESULT_TYPE.  */
7947   tree build_type = 0;
7948
7949   /* Nonzero means after finally constructing the expression
7950      convert it to this type.  */
7951   tree final_type = 0;
7952
7953   /* Nonzero if this is an operation like MIN or MAX which can
7954      safely be computed in short if both args are promoted shorts.
7955      Also implies COMMON.
7956      -1 indicates a bitwise operation; this makes a difference
7957      in the exact conditions for when it is safe to do the operation
7958      in a narrower mode.  */
7959   int shorten = 0;
7960
7961   /* Nonzero if this is a comparison operation;
7962      if both args are promoted shorts, compare the original shorts.
7963      Also implies COMMON.  */
7964   int short_compare = 0;
7965
7966   /* Nonzero if this is a right-shift operation, which can be computed on the
7967      original short and then promoted if the operand is a promoted short.  */
7968   int short_shift = 0;
7969
7970   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7971   int common = 0;
7972
7973   /* True means types are compatible as far as ObjC is concerned.  */
7974   bool objc_ok;
7975
7976   if (convert_p)
7977     {
7978       op0 = default_conversion (orig_op0);
7979       op1 = default_conversion (orig_op1);
7980     }
7981   else
7982     {
7983       op0 = orig_op0;
7984       op1 = orig_op1;
7985     }
7986
7987   type0 = TREE_TYPE (op0);
7988   type1 = TREE_TYPE (op1);
7989
7990   /* The expression codes of the data types of the arguments tell us
7991      whether the arguments are integers, floating, pointers, etc.  */
7992   code0 = TREE_CODE (type0);
7993   code1 = TREE_CODE (type1);
7994
7995   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7996   STRIP_TYPE_NOPS (op0);
7997   STRIP_TYPE_NOPS (op1);
7998
7999   /* If an error was already reported for one of the arguments,
8000      avoid reporting another error.  */
8001
8002   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8003     return error_mark_node;
8004
8005   if ((invalid_op_diag
8006        = targetm.invalid_binary_op (code, type0, type1)))
8007     {
8008       error (invalid_op_diag);
8009       return error_mark_node;
8010     }
8011
8012   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8013
8014   switch (code)
8015     {
8016     case PLUS_EXPR:
8017       /* Handle the pointer + int case.  */
8018       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8019         return pointer_int_sum (PLUS_EXPR, op0, op1);
8020       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8021         return pointer_int_sum (PLUS_EXPR, op1, op0);
8022       else
8023         common = 1;
8024       break;
8025
8026     case MINUS_EXPR:
8027       /* Subtraction of two similar pointers.
8028          We must subtract them as integers, then divide by object size.  */
8029       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8030           && comp_target_types (type0, type1))
8031         return pointer_diff (op0, op1);
8032       /* Handle pointer minus int.  Just like pointer plus int.  */
8033       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8034         return pointer_int_sum (MINUS_EXPR, op0, op1);
8035       else
8036         common = 1;
8037       break;
8038
8039     case MULT_EXPR:
8040       common = 1;
8041       break;
8042
8043     case TRUNC_DIV_EXPR:
8044     case CEIL_DIV_EXPR:
8045     case FLOOR_DIV_EXPR:
8046     case ROUND_DIV_EXPR:
8047     case EXACT_DIV_EXPR:
8048       warn_for_div_by_zero (op1);
8049
8050       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8051            || code0 == FIXED_POINT_TYPE
8052            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8053           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8054               || code1 == FIXED_POINT_TYPE
8055               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8056         {
8057           enum tree_code tcode0 = code0, tcode1 = code1;
8058
8059           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8060             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8061           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8062             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8063
8064           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8065               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8066             resultcode = RDIV_EXPR;
8067           else
8068             /* Although it would be tempting to shorten always here, that
8069                loses on some targets, since the modulo instruction is
8070                undefined if the quotient can't be represented in the
8071                computation mode.  We shorten only if unsigned or if
8072                dividing by something we know != -1.  */
8073             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8074                        || (TREE_CODE (op1) == INTEGER_CST
8075                            && !integer_all_onesp (op1)));
8076           common = 1;
8077         }
8078       break;
8079
8080     case BIT_AND_EXPR:
8081     case BIT_IOR_EXPR:
8082     case BIT_XOR_EXPR:
8083       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8084         shorten = -1;
8085       /* Allow vector types which are not floating point types.   */
8086       else if (code0 == VECTOR_TYPE
8087                && code1 == VECTOR_TYPE
8088                && !VECTOR_FLOAT_TYPE_P (type0)
8089                && !VECTOR_FLOAT_TYPE_P (type1))
8090         common = 1;
8091       break;
8092
8093     case TRUNC_MOD_EXPR:
8094     case FLOOR_MOD_EXPR:
8095       warn_for_div_by_zero (op1);
8096
8097       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8098         {
8099           /* Although it would be tempting to shorten always here, that loses
8100              on some targets, since the modulo instruction is undefined if the
8101              quotient can't be represented in the computation mode.  We shorten
8102              only if unsigned or if dividing by something we know != -1.  */
8103           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8104                      || (TREE_CODE (op1) == INTEGER_CST
8105                          && !integer_all_onesp (op1)));
8106           common = 1;
8107         }
8108       break;
8109
8110     case TRUTH_ANDIF_EXPR:
8111     case TRUTH_ORIF_EXPR:
8112     case TRUTH_AND_EXPR:
8113     case TRUTH_OR_EXPR:
8114     case TRUTH_XOR_EXPR:
8115       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8116            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8117            || code0 == FIXED_POINT_TYPE)
8118           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8119               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8120               || code1 == FIXED_POINT_TYPE))
8121         {
8122           /* Result of these operations is always an int,
8123              but that does not mean the operands should be
8124              converted to ints!  */
8125           result_type = integer_type_node;
8126           op0 = c_common_truthvalue_conversion (op0);
8127           op1 = c_common_truthvalue_conversion (op1);
8128           converted = 1;
8129         }
8130       break;
8131
8132       /* Shift operations: result has same type as first operand;
8133          always convert second operand to int.
8134          Also set SHORT_SHIFT if shifting rightward.  */
8135
8136     case RSHIFT_EXPR:
8137       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8138           && code1 == INTEGER_TYPE)
8139         {
8140           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8141             {
8142               if (tree_int_cst_sgn (op1) < 0)
8143                 warning (0, "right shift count is negative");
8144               else
8145                 {
8146                   if (!integer_zerop (op1))
8147                     short_shift = 1;
8148
8149                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8150                     warning (0, "right shift count >= width of type");
8151                 }
8152             }
8153
8154           /* Use the type of the value to be shifted.  */
8155           result_type = type0;
8156           /* Convert the shift-count to an integer, regardless of size
8157              of value being shifted.  */
8158           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8159             op1 = convert (integer_type_node, op1);
8160           /* Avoid converting op1 to result_type later.  */
8161           converted = 1;
8162         }
8163       break;
8164
8165     case LSHIFT_EXPR:
8166       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8167           && code1 == INTEGER_TYPE)
8168         {
8169           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8170             {
8171               if (tree_int_cst_sgn (op1) < 0)
8172                 warning (0, "left shift count is negative");
8173
8174               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8175                 warning (0, "left shift count >= width of type");
8176             }
8177
8178           /* Use the type of the value to be shifted.  */
8179           result_type = type0;
8180           /* Convert the shift-count to an integer, regardless of size
8181              of value being shifted.  */
8182           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8183             op1 = convert (integer_type_node, op1);
8184           /* Avoid converting op1 to result_type later.  */
8185           converted = 1;
8186         }
8187       break;
8188
8189     case EQ_EXPR:
8190     case NE_EXPR:
8191       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
8192         warning (OPT_Wfloat_equal,
8193                  "comparing floating point with == or != is unsafe");
8194       /* Result of comparison is always int,
8195          but don't convert the args to int!  */
8196       build_type = integer_type_node;
8197       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8198            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8199           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8200               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8201         short_compare = 1;
8202       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8203         {
8204           tree tt0 = TREE_TYPE (type0);
8205           tree tt1 = TREE_TYPE (type1);
8206           /* Anything compares with void *.  void * compares with anything.
8207              Otherwise, the targets must be compatible
8208              and both must be object or both incomplete.  */
8209           if (comp_target_types (type0, type1))
8210             result_type = common_pointer_type (type0, type1);
8211           else if (VOID_TYPE_P (tt0))
8212             {
8213               /* op0 != orig_op0 detects the case of something
8214                  whose value is 0 but which isn't a valid null ptr const.  */
8215               if (pedantic && !null_pointer_constant_p (orig_op0)
8216                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8217                 pedwarn ("ISO C forbids comparison of %<void *%>"
8218                          " with function pointer");
8219
8220               /* If this operand is a pointer into another address
8221                  space, make the result of the comparison such a
8222                  pointer also.  */
8223               if (OTHER_ADDR_SPACE_POINTER_TYPE_P (type0))
8224                 {
8225                   int qual = ENCODE_QUAL_ADDR_SPACE (TYPE_ADDR_SPACE (TREE_TYPE (type0)));
8226                   result_type = build_pointer_type
8227                     (build_qualified_type (void_type_node, qual));
8228                 }
8229             }
8230           else if (VOID_TYPE_P (tt1))
8231             {
8232               if (pedantic && !null_pointer_constant_p (orig_op1)
8233                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8234                 pedwarn ("ISO C forbids comparison of %<void *%>"
8235                          " with function pointer");
8236
8237               /* If this operand is a pointer into another address
8238                  space, make the result of the comparison such a
8239                  pointer also.  */
8240               if (OTHER_ADDR_SPACE_POINTER_TYPE_P (type1))
8241                 {
8242                   int qual = ENCODE_QUAL_ADDR_SPACE (TYPE_ADDR_SPACE (TREE_TYPE (type1)));
8243                   result_type = build_pointer_type
8244                     (build_qualified_type (void_type_node, qual));
8245                 }
8246             }
8247           else
8248             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8249             if (!objc_ok)
8250               pedwarn ("comparison of distinct pointer types lacks a cast");
8251
8252           if (result_type == NULL_TREE)
8253             result_type = ptr_type_node;
8254         }
8255       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8256         {
8257           if (TREE_CODE (op0) == ADDR_EXPR
8258               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8259             warning (OPT_Waddress, "the address of %qD will never be NULL",
8260                      TREE_OPERAND (op0, 0));
8261           result_type = type0;
8262         }
8263       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8264         {
8265           if (TREE_CODE (op1) == ADDR_EXPR
8266               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8267             warning (OPT_Waddress, "the address of %qD will never be NULL",
8268                      TREE_OPERAND (op1, 0));
8269           result_type = type1;
8270         }
8271       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8272         {
8273           result_type = type0;
8274           pedwarn ("comparison between pointer and integer");
8275         }
8276       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8277         {
8278           result_type = type1;
8279           pedwarn ("comparison between pointer and integer");
8280         }
8281       break;
8282
8283     case LE_EXPR:
8284     case GE_EXPR:
8285     case LT_EXPR:
8286     case GT_EXPR:
8287       build_type = integer_type_node;
8288       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8289            || code0 == FIXED_POINT_TYPE)
8290           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8291               || code1 == FIXED_POINT_TYPE))
8292         short_compare = 1;
8293       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8294         {
8295           if (comp_target_types (type0, type1))
8296             {
8297               result_type = common_pointer_type (type0, type1);
8298               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8299                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8300                 pedwarn ("comparison of complete and incomplete pointers");
8301               else if (pedantic
8302                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8303                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8304             }
8305           else
8306             {
8307               result_type = ptr_type_node;
8308               pedwarn ("comparison of distinct pointer types lacks a cast");
8309             }
8310         }
8311       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8312         {
8313           result_type = type0;
8314           if (pedantic || extra_warnings)
8315             pedwarn ("ordered comparison of pointer with integer zero");
8316         }
8317       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8318         {
8319           result_type = type1;
8320           if (pedantic)
8321             pedwarn ("ordered comparison of pointer with integer zero");
8322         }
8323       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8324         {
8325           result_type = type0;
8326           pedwarn ("comparison between pointer and integer");
8327         }
8328       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8329         {
8330           result_type = type1;
8331           pedwarn ("comparison between pointer and integer");
8332         }
8333       break;
8334
8335     default:
8336       gcc_unreachable ();
8337     }
8338
8339   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8340     return error_mark_node;
8341
8342   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8343       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8344           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8345                                                     TREE_TYPE (type1))))
8346     {
8347       binary_op_error (code, type0, type1);
8348       return error_mark_node;
8349     }
8350
8351   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8352        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8353       &&
8354       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8355        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8356     {
8357       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8358
8359       if (shorten || common || short_compare)
8360         {
8361           result_type = c_common_type (type0, type1);
8362           if (result_type == error_mark_node)
8363             return error_mark_node;
8364         }
8365
8366       /* For certain operations (which identify themselves by shorten != 0)
8367          if both args were extended from the same smaller type,
8368          do the arithmetic in that type and then extend.
8369
8370          shorten !=0 and !=1 indicates a bitwise operation.
8371          For them, this optimization is safe only if
8372          both args are zero-extended or both are sign-extended.
8373          Otherwise, we might change the result.
8374          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8375          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8376
8377       if (shorten && none_complex)
8378         {
8379           int unsigned0, unsigned1;
8380           tree arg0, arg1;
8381           int uns;
8382           tree type;
8383
8384           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8385              excessive narrowing when we call get_narrower below.  For
8386              example, suppose that OP0 is of unsigned int extended
8387              from signed char and that RESULT_TYPE is long long int.
8388              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8389              like
8390
8391                (long long int) (unsigned int) signed_char
8392
8393              which get_narrower would narrow down to
8394
8395                (unsigned int) signed char
8396
8397              If we do not cast OP0 first, get_narrower would return
8398              signed_char, which is inconsistent with the case of the
8399              explicit cast.  */
8400           op0 = convert (result_type, op0);
8401           op1 = convert (result_type, op1);
8402
8403           arg0 = get_narrower (op0, &unsigned0);
8404           arg1 = get_narrower (op1, &unsigned1);
8405
8406           /* UNS is 1 if the operation to be done is an unsigned one.  */
8407           uns = TYPE_UNSIGNED (result_type);
8408
8409           final_type = result_type;
8410
8411           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8412              but it *requires* conversion to FINAL_TYPE.  */
8413
8414           if ((TYPE_PRECISION (TREE_TYPE (op0))
8415                == TYPE_PRECISION (TREE_TYPE (arg0)))
8416               && TREE_TYPE (op0) != final_type)
8417             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8418           if ((TYPE_PRECISION (TREE_TYPE (op1))
8419                == TYPE_PRECISION (TREE_TYPE (arg1)))
8420               && TREE_TYPE (op1) != final_type)
8421             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8422
8423           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8424
8425           /* For bitwise operations, signedness of nominal type
8426              does not matter.  Consider only how operands were extended.  */
8427           if (shorten == -1)
8428             uns = unsigned0;
8429
8430           /* Note that in all three cases below we refrain from optimizing
8431              an unsigned operation on sign-extended args.
8432              That would not be valid.  */
8433
8434           /* Both args variable: if both extended in same way
8435              from same width, do it in that width.
8436              Do it unsigned if args were zero-extended.  */
8437           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8438                < TYPE_PRECISION (result_type))
8439               && (TYPE_PRECISION (TREE_TYPE (arg1))
8440                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8441               && unsigned0 == unsigned1
8442               && (unsigned0 || !uns))
8443             result_type
8444               = c_common_signed_or_unsigned_type
8445               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8446           else if (TREE_CODE (arg0) == INTEGER_CST
8447                    && (unsigned1 || !uns)
8448                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8449                        < TYPE_PRECISION (result_type))
8450                    && (type
8451                        = c_common_signed_or_unsigned_type (unsigned1,
8452                                                            TREE_TYPE (arg1)))
8453                    && !POINTER_TYPE_P (type)
8454                    && int_fits_type_p (arg0, type))
8455             result_type = type;
8456           else if (TREE_CODE (arg1) == INTEGER_CST
8457                    && (unsigned0 || !uns)
8458                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8459                        < TYPE_PRECISION (result_type))
8460                    && (type
8461                        = c_common_signed_or_unsigned_type (unsigned0,
8462                                                            TREE_TYPE (arg0)))
8463                    && !POINTER_TYPE_P (type)
8464                    && int_fits_type_p (arg1, type))
8465             result_type = type;
8466         }
8467
8468       /* Shifts can be shortened if shifting right.  */
8469
8470       if (short_shift)
8471         {
8472           int unsigned_arg;
8473           tree arg0 = get_narrower (op0, &unsigned_arg);
8474
8475           final_type = result_type;
8476
8477           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8478             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8479
8480           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8481               && tree_int_cst_sgn (op1) > 0
8482               /* We can shorten only if the shift count is less than the
8483                  number of bits in the smaller type size.  */
8484               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8485               /* We cannot drop an unsigned shift after sign-extension.  */
8486               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8487             {
8488               /* Do an unsigned shift if the operand was zero-extended.  */
8489               result_type
8490                 = c_common_signed_or_unsigned_type (unsigned_arg,
8491                                                     TREE_TYPE (arg0));
8492               /* Convert value-to-be-shifted to that type.  */
8493               if (TREE_TYPE (op0) != result_type)
8494                 op0 = convert (result_type, op0);
8495               converted = 1;
8496             }
8497         }
8498
8499       /* Comparison operations are shortened too but differently.
8500          They identify themselves by setting short_compare = 1.  */
8501
8502       if (short_compare)
8503         {
8504           /* Don't write &op0, etc., because that would prevent op0
8505              from being kept in a register.
8506              Instead, make copies of the our local variables and
8507              pass the copies by reference, then copy them back afterward.  */
8508           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8509           enum tree_code xresultcode = resultcode;
8510           tree val
8511             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8512
8513           if (val != 0)
8514             return val;
8515
8516           op0 = xop0, op1 = xop1;
8517           converted = 1;
8518           resultcode = xresultcode;
8519
8520           if (warn_sign_compare && skip_evaluation == 0)
8521             {
8522               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8523               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8524               int unsignedp0, unsignedp1;
8525               tree primop0 = get_narrower (op0, &unsignedp0);
8526               tree primop1 = get_narrower (op1, &unsignedp1);
8527
8528               xop0 = orig_op0;
8529               xop1 = orig_op1;
8530               STRIP_TYPE_NOPS (xop0);
8531               STRIP_TYPE_NOPS (xop1);
8532
8533               /* Give warnings for comparisons between signed and unsigned
8534                  quantities that may fail.
8535
8536                  Do the checking based on the original operand trees, so that
8537                  casts will be considered, but default promotions won't be.
8538
8539                  Do not warn if the comparison is being done in a signed type,
8540                  since the signed type will only be chosen if it can represent
8541                  all the values of the unsigned type.  */
8542               if (!TYPE_UNSIGNED (result_type))
8543                 /* OK */;
8544               /* Do not warn if both operands are the same signedness.  */
8545               else if (op0_signed == op1_signed)
8546                 /* OK */;
8547               else
8548                 {
8549                   tree sop, uop;
8550                   bool ovf;
8551
8552                   if (op0_signed)
8553                     sop = xop0, uop = xop1;
8554                   else
8555                     sop = xop1, uop = xop0;
8556
8557                   /* Do not warn if the signed quantity is an
8558                      unsuffixed integer literal (or some static
8559                      constant expression involving such literals or a
8560                      conditional expression involving such literals)
8561                      and it is non-negative.  */
8562                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8563                     /* OK */;
8564                   /* Do not warn if the comparison is an equality operation,
8565                      the unsigned quantity is an integral constant, and it
8566                      would fit in the result if the result were signed.  */
8567                   else if (TREE_CODE (uop) == INTEGER_CST
8568                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8569                            && int_fits_type_p
8570                            (uop, c_common_signed_type (result_type)))
8571                     /* OK */;
8572                   /* Do not warn if the unsigned quantity is an enumeration
8573                      constant and its maximum value would fit in the result
8574                      if the result were signed.  */
8575                   else if (TREE_CODE (uop) == INTEGER_CST
8576                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8577                            && int_fits_type_p
8578                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8579                             c_common_signed_type (result_type)))
8580                     /* OK */;
8581                   else
8582                     warning (OPT_Wsign_compare, "comparison between signed and unsigned");
8583                 }
8584
8585               /* Warn if two unsigned values are being compared in a size
8586                  larger than their original size, and one (and only one) is the
8587                  result of a `~' operator.  This comparison will always fail.
8588
8589                  Also warn if one operand is a constant, and the constant
8590                  does not have all bits set that are set in the ~ operand
8591                  when it is extended.  */
8592
8593               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8594                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8595                 {
8596                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8597                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8598                                             &unsignedp0);
8599                   else
8600                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8601                                             &unsignedp1);
8602
8603                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8604                     {
8605                       tree primop;
8606                       HOST_WIDE_INT constant, mask;
8607                       int unsignedp, bits;
8608
8609                       if (host_integerp (primop0, 0))
8610                         {
8611                           primop = primop1;
8612                           unsignedp = unsignedp1;
8613                           constant = tree_low_cst (primop0, 0);
8614                         }
8615                       else
8616                         {
8617                           primop = primop0;
8618                           unsignedp = unsignedp0;
8619                           constant = tree_low_cst (primop1, 0);
8620                         }
8621
8622                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8623                       if (bits < TYPE_PRECISION (result_type)
8624                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8625                         {
8626                           mask = (~(HOST_WIDE_INT) 0) << bits;
8627                           if ((mask & constant) != mask)
8628                             warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with constant");
8629                         }
8630                     }
8631                   else if (unsignedp0 && unsignedp1
8632                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8633                                < TYPE_PRECISION (result_type))
8634                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8635                                < TYPE_PRECISION (result_type)))
8636                     warning (OPT_Wsign_compare, "comparison of promoted ~unsigned with unsigned");
8637                 }
8638             }
8639         }
8640     }
8641
8642   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8643      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8644      Then the expression will be built.
8645      It will be given type FINAL_TYPE if that is nonzero;
8646      otherwise, it will be given type RESULT_TYPE.  */
8647
8648   if (!result_type)
8649     {
8650       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8651       return error_mark_node;
8652     }
8653
8654   if (!converted)
8655     {
8656       if (TREE_TYPE (op0) != result_type)
8657         op0 = convert_and_check (result_type, op0);
8658       if (TREE_TYPE (op1) != result_type)
8659         op1 = convert_and_check (result_type, op1);
8660
8661       /* This can happen if one operand has a vector type, and the other
8662          has a different type.  */
8663       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8664         return error_mark_node;
8665     }
8666
8667   if (build_type == NULL_TREE)
8668     build_type = result_type;
8669
8670   {
8671     /* Treat expressions in initializers specially as they can't trap.  */
8672     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8673                                                                     build_type,
8674                                                                     op0, op1)
8675                                          : fold_build2 (resultcode, build_type,
8676                                                         op0, op1);
8677
8678     if (final_type != 0)
8679       result = convert (final_type, result);
8680     return result;
8681   }
8682 }
8683
8684
8685 /* Convert EXPR to be a truth-value, validating its type for this
8686    purpose.  */
8687
8688 tree
8689 c_objc_common_truthvalue_conversion (tree expr)
8690 {
8691   switch (TREE_CODE (TREE_TYPE (expr)))
8692     {
8693     case ARRAY_TYPE:
8694       error ("used array that cannot be converted to pointer where scalar is required");
8695       return error_mark_node;
8696
8697     case RECORD_TYPE:
8698       error ("used struct type value where scalar is required");
8699       return error_mark_node;
8700
8701     case UNION_TYPE:
8702       error ("used union type value where scalar is required");
8703       return error_mark_node;
8704
8705     case FUNCTION_TYPE:
8706       gcc_unreachable ();
8707
8708     default:
8709       break;
8710     }
8711
8712   /* ??? Should we also give an error for void and vectors rather than
8713      leaving those to give errors later?  */
8714   return c_common_truthvalue_conversion (expr);
8715 }
8716 \f
8717
8718 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8719    required.  */
8720
8721 tree
8722 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8723                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8724 {
8725   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8726     {
8727       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8728       /* Executing a compound literal inside a function reinitializes
8729          it.  */
8730       if (!TREE_STATIC (decl))
8731         *se = true;
8732       return decl;
8733     }
8734   else
8735     return expr;
8736 }
8737 \f
8738 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8739
8740 tree
8741 c_begin_omp_parallel (void)
8742 {
8743   tree block;
8744
8745   keep_next_level ();
8746   block = c_begin_compound_stmt (true);
8747
8748   return block;
8749 }
8750
8751 tree
8752 c_finish_omp_parallel (tree clauses, tree block)
8753 {
8754   tree stmt;
8755
8756   block = c_end_compound_stmt (block, true);
8757
8758   stmt = make_node (OMP_PARALLEL);
8759   TREE_TYPE (stmt) = void_type_node;
8760   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8761   OMP_PARALLEL_BODY (stmt) = block;
8762
8763   return add_stmt (stmt);
8764 }
8765
8766 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8767    Remove any elements from the list that are invalid.  */
8768
8769 tree
8770 c_finish_omp_clauses (tree clauses)
8771 {
8772   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8773   tree c, t, *pc = &clauses;
8774   const char *name;
8775
8776   bitmap_obstack_initialize (NULL);
8777   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8778   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8779   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8780
8781   for (pc = &clauses, c = clauses; c ; c = *pc)
8782     {
8783       bool remove = false;
8784       bool need_complete = false;
8785       bool need_implicitly_determined = false;
8786
8787       switch (OMP_CLAUSE_CODE (c))
8788         {
8789         case OMP_CLAUSE_SHARED:
8790           name = "shared";
8791           need_implicitly_determined = true;
8792           goto check_dup_generic;
8793
8794         case OMP_CLAUSE_PRIVATE:
8795           name = "private";
8796           need_complete = true;
8797           need_implicitly_determined = true;
8798           goto check_dup_generic;
8799
8800         case OMP_CLAUSE_REDUCTION:
8801           name = "reduction";
8802           need_implicitly_determined = true;
8803           t = OMP_CLAUSE_DECL (c);
8804           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8805               || POINTER_TYPE_P (TREE_TYPE (t)))
8806             {
8807               error ("%qE has invalid type for %<reduction%>", t);
8808               remove = true;
8809             }
8810           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8811             {
8812               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8813               const char *r_name = NULL;
8814
8815               switch (r_code)
8816                 {
8817                 case PLUS_EXPR:
8818                 case MULT_EXPR:
8819                 case MINUS_EXPR:
8820                   break;
8821                 case BIT_AND_EXPR:
8822                   r_name = "&";
8823                   break;
8824                 case BIT_XOR_EXPR:
8825                   r_name = "^";
8826                   break;
8827                 case BIT_IOR_EXPR:
8828                   r_name = "|";
8829                   break;
8830                 case TRUTH_ANDIF_EXPR:
8831                   r_name = "&&";
8832                   break;
8833                 case TRUTH_ORIF_EXPR:
8834                   r_name = "||";
8835                   break;
8836                 default:
8837                   gcc_unreachable ();
8838                 }
8839               if (r_name)
8840                 {
8841                   error ("%qE has invalid type for %<reduction(%s)%>",
8842                          t, r_name);
8843                   remove = true;
8844                 }
8845             }
8846           goto check_dup_generic;
8847
8848         case OMP_CLAUSE_COPYPRIVATE:
8849           name = "copyprivate";
8850           goto check_dup_generic;
8851
8852         case OMP_CLAUSE_COPYIN:
8853           name = "copyin";
8854           t = OMP_CLAUSE_DECL (c);
8855           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8856             {
8857               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8858               remove = true;
8859             }
8860           goto check_dup_generic;
8861
8862         check_dup_generic:
8863           t = OMP_CLAUSE_DECL (c);
8864           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8865             {
8866               error ("%qE is not a variable in clause %qs", t, name);
8867               remove = true;
8868             }
8869           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8870                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8871                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8872             {
8873               error ("%qE appears more than once in data clauses", t);
8874               remove = true;
8875             }
8876           else
8877             bitmap_set_bit (&generic_head, DECL_UID (t));
8878           break;
8879
8880         case OMP_CLAUSE_FIRSTPRIVATE:
8881           name = "firstprivate";
8882           t = OMP_CLAUSE_DECL (c);
8883           need_complete = true;
8884           need_implicitly_determined = true;
8885           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8886             {
8887               error ("%qE is not a variable in clause %<firstprivate%>", t);
8888               remove = true;
8889             }
8890           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8891                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8892             {
8893               error ("%qE appears more than once in data clauses", t);
8894               remove = true;
8895             }
8896           else
8897             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8898           break;
8899
8900         case OMP_CLAUSE_LASTPRIVATE:
8901           name = "lastprivate";
8902           t = OMP_CLAUSE_DECL (c);
8903           need_complete = true;
8904           need_implicitly_determined = true;
8905           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8906             {
8907               error ("%qE is not a variable in clause %<lastprivate%>", t);
8908               remove = true;
8909             }
8910           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8911                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8912             {
8913               error ("%qE appears more than once in data clauses", t);
8914               remove = true;
8915             }
8916           else
8917             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8918           break;
8919
8920         case OMP_CLAUSE_IF:
8921         case OMP_CLAUSE_NUM_THREADS:
8922         case OMP_CLAUSE_SCHEDULE:
8923         case OMP_CLAUSE_NOWAIT:
8924         case OMP_CLAUSE_ORDERED:
8925         case OMP_CLAUSE_DEFAULT:
8926           pc = &OMP_CLAUSE_CHAIN (c);
8927           continue;
8928
8929         default:
8930           gcc_unreachable ();
8931         }
8932
8933       if (!remove)
8934         {
8935           t = OMP_CLAUSE_DECL (c);
8936
8937           if (need_complete)
8938             {
8939               t = require_complete_type (t);
8940               if (t == error_mark_node)
8941                 remove = true;
8942             }
8943
8944           if (need_implicitly_determined)
8945             {
8946               const char *share_name = NULL;
8947
8948               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8949                 share_name = "threadprivate";
8950               else switch (c_omp_predetermined_sharing (t))
8951                 {
8952                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8953                   break;
8954                 case OMP_CLAUSE_DEFAULT_SHARED:
8955                   share_name = "shared";
8956                   break;
8957                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8958                   share_name = "private";
8959                   break;
8960                 default:
8961                   gcc_unreachable ();
8962                 }
8963               if (share_name)
8964                 {
8965                   error ("%qE is predetermined %qs for %qs",
8966                          t, share_name, name);
8967                   remove = true;
8968                 }
8969             }
8970         }
8971
8972       if (remove)
8973         *pc = OMP_CLAUSE_CHAIN (c);
8974       else
8975         pc = &OMP_CLAUSE_CHAIN (c);
8976     }
8977
8978   bitmap_obstack_release (NULL);
8979   return clauses;
8980 }
8981
8982 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8983    down to the element type of an array.  */
8984
8985 tree
8986 c_build_qualified_type (tree type, int type_quals)
8987 {
8988   if (type == error_mark_node)
8989     return type;
8990
8991   if (TREE_CODE (type) == ARRAY_TYPE)
8992     {
8993       tree t;
8994       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8995                                                   type_quals);
8996
8997       /* See if we already have an identically qualified type.  */
8998       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8999         {
9000           if (TYPE_QUALS (strip_array_types (t)) == type_quals
9001               && TYPE_NAME (t) == TYPE_NAME (type)
9002               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
9003               && attribute_list_equal (TYPE_ATTRIBUTES (t),
9004                                        TYPE_ATTRIBUTES (type)))
9005             break;
9006         }
9007       if (!t)
9008         {
9009           tree domain = TYPE_DOMAIN (type);
9010
9011           t = build_variant_type_copy (type);
9012           TREE_TYPE (t) = element_type;
9013
9014           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
9015               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
9016             SET_TYPE_STRUCTURAL_EQUALITY (t);
9017           else if (TYPE_CANONICAL (element_type) != element_type
9018                    || (domain && TYPE_CANONICAL (domain) != domain))
9019             {
9020               tree unqualified_canon
9021                 = build_array_type (TYPE_CANONICAL (element_type),
9022                                     domain? TYPE_CANONICAL (domain)
9023                                           : NULL_TREE);
9024               TYPE_CANONICAL (t)
9025                 = c_build_qualified_type (unqualified_canon, type_quals);
9026             }
9027           else
9028             TYPE_CANONICAL (t) = t;
9029         }
9030       return t;
9031     }
9032
9033   /* A restrict-qualified pointer type must be a pointer to object or
9034      incomplete type.  Note that the use of POINTER_TYPE_P also allows
9035      REFERENCE_TYPEs, which is appropriate for C++.  */
9036   if ((type_quals & TYPE_QUAL_RESTRICT)
9037       && (!POINTER_TYPE_P (type)
9038           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
9039     {
9040       error ("invalid use of %<restrict%>");
9041       type_quals &= ~TYPE_QUAL_RESTRICT;
9042     }
9043
9044   return build_qualified_type (type, type_quals);
9045 }