gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "c-lang.h"
  37 #include "tm_p.h"
  38 #include "flags.h"
  39 #include "output.h"
  40 #include "expr.h"
  41 #include "toplev.h"
  42 #include "intl.h"
  43 #include "ggc.h"
  44 #include "target.h"
  45 #include "tree-iterator.h"
  46 #include "gimple.h"
  47 #include "tree-flow.h"
  48
  49 /* Possible cases of implicit bad conversions.  Used to select
  50    diagnostic messages in convert_for_assignment.  */
  51 enum impl_conv {
  52   ic_argpass,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* Whether we are building a boolean conversion inside
  59    convert_for_assignment, or some other late binary operation.  If
  60    build_binary_op is called (from code shared with C++) in this case,
  61    then the operands have already been folded and the result will not
  62    be folded again, so C_MAYBE_CONST_EXPR should not be generated.  */
  63 bool in_late_binary_op;
  64
  65 /* The level of nesting inside "__alignof__".  */
  66 int in_alignof;
  67
  68 /* The level of nesting inside "sizeof".  */
  69 int in_sizeof;
  70
  71 /* The level of nesting inside "typeof".  */
  72 int in_typeof;
  73
  74 /* Nonzero if we've already printed a "missing braces around initializer"
  75    message within this initializer.  */
  76 static int missing_braces_mentioned;
  77
  78 static int require_constant_value;
  79 static int require_constant_elements;
  80
  81 static bool null_pointer_constant_p (const_tree);
  82 static tree qualify_type (tree, tree);
  83 static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *);
  84 static int comp_target_types (location_t, tree, tree);
  85 static int function_types_compatible_p (const_tree, const_tree, bool *);
  86 static int type_lists_compatible_p (const_tree, const_tree, bool *);
  87 static tree lookup_field (tree, tree);
  88 static int convert_arguments (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
  89                               tree);
  90 static tree pointer_diff (location_t, tree, tree);
  91 static tree convert_for_assignment (location_t, tree, tree, tree,
  92                                     enum impl_conv, bool, tree, tree, int);
  93 static tree valid_compound_expr_initializer (tree, tree);
  94 static void push_string (const char *);
  95 static void push_member_name (tree);
  96 static int spelling_length (void);
  97 static char *print_spelling (char *);
  98 static void warning_init (int, const char *);
  99 static tree digest_init (location_t, tree, tree, tree, bool, bool, int);
 100 static void output_init_element (tree, tree, bool, tree, tree, int, bool);
 101 static void output_pending_init_elements (int);
 102 static int set_designator (int);
 103 static void push_range_stack (tree);
 104 static void add_pending_init (tree, tree, tree, bool);
 105 static void set_nonincremental_init (void);
 106 static void set_nonincremental_init_from_string (tree);
 107 static tree find_init_member (tree);
 108 static void readonly_error (tree, enum lvalue_use);
 109 static void readonly_warning (tree, enum lvalue_use);
 110 static int lvalue_or_else (const_tree, enum lvalue_use);
 111 static void record_maybe_used_decl (tree);
 112 static int comptypes_internal (const_tree, const_tree, bool *);
 113 \f
 114 /* Return true if EXP is a null pointer constant, false otherwise.  */
 115
 116 static bool
 117 null_pointer_constant_p (const_tree expr)
 118 {
 119   /* This should really operate on c_expr structures, but they aren't
 120      yet available everywhere required.  */
 121   tree type = TREE_TYPE (expr);
 122   return (TREE_CODE (expr) == INTEGER_CST
 123           && !TREE_OVERFLOW (expr)
 124           && integer_zerop (expr)
 125           && (INTEGRAL_TYPE_P (type)
 126               || (TREE_CODE (type) == POINTER_TYPE
 127                   && VOID_TYPE_P (TREE_TYPE (type))
 128                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 129 }
 130
 131 /* EXPR may appear in an unevaluated part of an integer constant
 132    expression, but not in an evaluated part.  Wrap it in a
 133    C_MAYBE_CONST_EXPR, or mark it with TREE_OVERFLOW if it is just an
 134    INTEGER_CST and we cannot create a C_MAYBE_CONST_EXPR.  */
 135
 136 static tree
 137 note_integer_operands (tree expr)
 138 {
 139   tree ret;
 140   if (TREE_CODE (expr) == INTEGER_CST && in_late_binary_op)
 141     {
 142       ret = copy_node (expr);
 143       TREE_OVERFLOW (ret) = 1;
 144     }
 145   else
 146     {
 147       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (expr), NULL_TREE, expr);
 148       C_MAYBE_CONST_EXPR_INT_OPERANDS (ret) = 1;
 149     }
 150   return ret;
 151 }
 152
 153 /* Having checked whether EXPR may appear in an unevaluated part of an
 154    integer constant expression and found that it may, remove any
 155    C_MAYBE_CONST_EXPR noting this fact and return the resulting
 156    expression.  */
 157
 158 static inline tree
 159 remove_c_maybe_const_expr (tree expr)
 160 {
 161   if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR)
 162     return C_MAYBE_CONST_EXPR_EXPR (expr);
 163   else
 164     return expr;
 165 }
 166
 167 \f/* This is a cache to hold if two types are compatible or not.  */
 168
 169 struct tagged_tu_seen_cache {
 170   const struct tagged_tu_seen_cache * next;
 171   const_tree t1;
 172   const_tree t2;
 173   /* The return value of tagged_types_tu_compatible_p if we had seen
 174      these two types already.  */
 175   int val;
 176 };
 177
 178 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 179 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 180
 181 /* Do `exp = require_complete_type (exp);' to make sure exp
 182    does not have an incomplete type.  (That includes void types.)  */
 183
 184 tree
 185 require_complete_type (tree value)
 186 {
 187   tree type = TREE_TYPE (value);
 188
 189   if (value == error_mark_node || type == error_mark_node)
 190     return error_mark_node;
 191
 192   /* First, detect a valid value with a complete type.  */
 193   if (COMPLETE_TYPE_P (type))
 194     return value;
 195
 196   c_incomplete_type_error (value, type);
 197   return error_mark_node;
 198 }
 199
 200 /* Print an error message for invalid use of an incomplete type.
 201    VALUE is the expression that was used (or 0 if that isn't known)
 202    and TYPE is the type that was invalid.  */
 203
 204 void
 205 c_incomplete_type_error (const_tree value, const_tree type)
 206 {
 207   const char *type_code_string;
 208
 209   /* Avoid duplicate error message.  */
 210   if (TREE_CODE (type) == ERROR_MARK)
 211     return;
 212
 213   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 214                      || TREE_CODE (value) == PARM_DECL))
 215     error ("%qD has an incomplete type", value);
 216   else
 217     {
 218     retry:
 219       /* We must print an error message.  Be clever about what it says.  */
 220
 221       switch (TREE_CODE (type))
 222         {
 223         case RECORD_TYPE:
 224           type_code_string = "struct";
 225           break;
 226
 227         case UNION_TYPE:
 228           type_code_string = "union";
 229           break;
 230
 231         case ENUMERAL_TYPE:
 232           type_code_string = "enum";
 233           break;
 234
 235         case VOID_TYPE:
 236           error ("invalid use of void expression");
 237           return;
 238
 239         case ARRAY_TYPE:
 240           if (TYPE_DOMAIN (type))
 241             {
 242               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 243                 {
 244                   error ("invalid use of flexible array member");
 245                   return;
 246                 }
 247               type = TREE_TYPE (type);
 248               goto retry;
 249             }
 250           error ("invalid use of array with unspecified bounds");
 251           return;
 252
 253         default:
 254           gcc_unreachable ();
 255         }
 256
 257       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 258         error ("invalid use of undefined type %<%s %E%>",
 259                type_code_string, TYPE_NAME (type));
 260       else
 261         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 262         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 263     }
 264 }
 265
 266 /* Given a type, apply default promotions wrt unnamed function
 267    arguments and return the new type.  */
 268
 269 tree
 270 c_type_promotes_to (tree type)
 271 {
 272   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 273     return double_type_node;
 274
 275   if (c_promoting_integer_type_p (type))
 276     {
 277       /* Preserve unsignedness if not really getting any wider.  */
 278       if (TYPE_UNSIGNED (type)
 279           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 280         return unsigned_type_node;
 281       return integer_type_node;
 282     }
 283
 284   return type;
 285 }
 286
 287 /* Return true if between two named address spaces, whether there is a superset
 288    named address space that encompasses both address spaces.  If there is a
 289    superset, return which address space is the superset.  */
 290
 291 static bool
 292 addr_space_superset (addr_space_t as1, addr_space_t as2, addr_space_t *common)
 293 {
 294   if (as1 == as2)
 295     {
 296       *common = as1;
 297       return true;
 298     }
 299   else if (targetm.addr_space.subset_p (as1, as2))
 300     {
 301       *common = as2;
 302       return true;
 303     }
 304   else if (targetm.addr_space.subset_p (as2, as1))
 305     {
 306       *common = as1;
 307       return true;
 308     }
 309   else
 310     return false;
 311 }
 312
 313 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 314    as well as those of TYPE.  */
 315
 316 static tree
 317 qualify_type (tree type, tree like)
 318 {
 319   addr_space_t as_type = TYPE_ADDR_SPACE (type);
 320   addr_space_t as_like = TYPE_ADDR_SPACE (like);
 321   addr_space_t as_common;
 322
 323   /* If the two named address spaces are different, determine the common
 324      superset address space.  If there isn't one, raise an error.  */
 325   if (!addr_space_superset (as_type, as_like, &as_common))
 326     {
 327       as_common = as_type;
 328       error ("%qT and %qT are in disjoint named address spaces",
 329              type, like);
 330     }
 331
 332   return c_build_qualified_type (type,
 333                                  TYPE_QUALS_NO_ADDR_SPACE (type)
 334                                  | TYPE_QUALS_NO_ADDR_SPACE (like)
 335                                  | ENCODE_QUAL_ADDR_SPACE (as_common));
 336 }
 337
 338 /* Return true iff the given tree T is a variable length array.  */
 339
 340 bool
 341 c_vla_type_p (const_tree t)
 342 {
 343   if (TREE_CODE (t) == ARRAY_TYPE
 344       && C_TYPE_VARIABLE_SIZE (t))
 345     return true;
 346   return false;
 347 }
 348 \f
 349 /* Return the composite type of two compatible types.
 350
 351    We assume that comptypes has already been done and returned
 352    nonzero; if that isn't so, this may crash.  In particular, we
 353    assume that qualifiers match.  */
 354
 355 tree
 356 composite_type (tree t1, tree t2)
 357 {
 358   enum tree_code code1;
 359   enum tree_code code2;
 360   tree attributes;
 361
 362   /* Save time if the two types are the same.  */
 363
 364   if (t1 == t2) return t1;
 365
 366   /* If one type is nonsense, use the other.  */
 367   if (t1 == error_mark_node)
 368     return t2;
 369   if (t2 == error_mark_node)
 370     return t1;
 371
 372   code1 = TREE_CODE (t1);
 373   code2 = TREE_CODE (t2);
 374
 375   /* Merge the attributes.  */
 376   attributes = targetm.merge_type_attributes (t1, t2);
 377
 378   /* If one is an enumerated type and the other is the compatible
 379      integer type, the composite type might be either of the two
 380      (DR#013 question 3).  For consistency, use the enumerated type as
 381      the composite type.  */
 382
 383   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 384     return t1;
 385   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 386     return t2;
 387
 388   gcc_assert (code1 == code2);
 389
 390   switch (code1)
 391     {
 392     case POINTER_TYPE:
 393       /* For two pointers, do this recursively on the target type.  */
 394       {
 395         tree pointed_to_1 = TREE_TYPE (t1);
 396         tree pointed_to_2 = TREE_TYPE (t2);
 397         tree target = composite_type (pointed_to_1, pointed_to_2);
 398         t1 = build_pointer_type (target);
 399         t1 = build_type_attribute_variant (t1, attributes);
 400         return qualify_type (t1, t2);
 401       }
 402
 403     case ARRAY_TYPE:
 404       {
 405         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 406         int quals;
 407         tree unqual_elt;
 408         tree d1 = TYPE_DOMAIN (t1);
 409         tree d2 = TYPE_DOMAIN (t2);
 410         bool d1_variable, d2_variable;
 411         bool d1_zero, d2_zero;
 412         bool t1_complete, t2_complete;
 413
 414         /* We should not have any type quals on arrays at all.  */
 415         gcc_assert (!TYPE_QUALS_NO_ADDR_SPACE (t1)
 416                     && !TYPE_QUALS_NO_ADDR_SPACE (t2));
 417
 418         t1_complete = COMPLETE_TYPE_P (t1);
 419         t2_complete = COMPLETE_TYPE_P (t2);
 420
 421         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 422         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 423
 424         d1_variable = (!d1_zero
 425                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 426                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 427         d2_variable = (!d2_zero
 428                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 429                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 430         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 431         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 432
 433         /* Save space: see if the result is identical to one of the args.  */
 434         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 435             && (d2_variable || d2_zero || !d1_variable))
 436           return build_type_attribute_variant (t1, attributes);
 437         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 438             && (d1_variable || d1_zero || !d2_variable))
 439           return build_type_attribute_variant (t2, attributes);
 440
 441         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 442           return build_type_attribute_variant (t1, attributes);
 443         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 444           return build_type_attribute_variant (t2, attributes);
 445
 446         /* Merge the element types, and have a size if either arg has
 447            one.  We may have qualifiers on the element types.  To set
 448            up TYPE_MAIN_VARIANT correctly, we need to form the
 449            composite of the unqualified types and add the qualifiers
 450            back at the end.  */
 451         quals = TYPE_QUALS (strip_array_types (elt));
 452         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 453         t1 = build_array_type (unqual_elt,
 454                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 455                                              && (d2_variable
 456                                                  || d2_zero
 457                                                  || !d1_variable))
 458                                             ? t1
 459                                             : t2));
 460         /* Ensure a composite type involving a zero-length array type
 461            is a zero-length type not an incomplete type.  */
 462         if (d1_zero && d2_zero
 463             && (t1_complete || t2_complete)
 464             && !COMPLETE_TYPE_P (t1))
 465           {
 466             TYPE_SIZE (t1) = bitsize_zero_node;
 467             TYPE_SIZE_UNIT (t1) = size_zero_node;
 468           }
 469         t1 = c_build_qualified_type (t1, quals);
 470         return build_type_attribute_variant (t1, attributes);
 471       }
 472
 473     case ENUMERAL_TYPE:
 474     case RECORD_TYPE:
 475     case UNION_TYPE:
 476       if (attributes != NULL)
 477         {
 478           /* Try harder not to create a new aggregate type.  */
 479           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 480             return t1;
 481           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 482             return t2;
 483         }
 484       return build_type_attribute_variant (t1, attributes);
 485
 486     case FUNCTION_TYPE:
 487       /* Function types: prefer the one that specified arg types.
 488          If both do, merge the arg types.  Also merge the return types.  */
 489       {
 490         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 491         tree p1 = TYPE_ARG_TYPES (t1);
 492         tree p2 = TYPE_ARG_TYPES (t2);
 493         int len;
 494         tree newargs, n;
 495         int i;
 496
 497         /* Save space: see if the result is identical to one of the args.  */
 498         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 499           return build_type_attribute_variant (t1, attributes);
 500         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 501           return build_type_attribute_variant (t2, attributes);
 502
 503         /* Simple way if one arg fails to specify argument types.  */
 504         if (TYPE_ARG_TYPES (t1) == 0)
 505          {
 506             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 507             t1 = build_type_attribute_variant (t1, attributes);
 508             return qualify_type (t1, t2);
 509          }
 510         if (TYPE_ARG_TYPES (t2) == 0)
 511          {
 512            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 513            t1 = build_type_attribute_variant (t1, attributes);
 514            return qualify_type (t1, t2);
 515          }
 516
 517         /* If both args specify argument types, we must merge the two
 518            lists, argument by argument.  */
 519         /* Tell global_bindings_p to return false so that variable_size
 520            doesn't die on VLAs in parameter types.  */
 521         c_override_global_bindings_to_false = true;
 522
 523         len = list_length (p1);
 524         newargs = 0;
 525
 526         for (i = 0; i < len; i++)
 527           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 528
 529         n = newargs;
 530
 531         for (; p1;
 532              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 533           {
 534             /* A null type means arg type is not specified.
 535                Take whatever the other function type has.  */
 536             if (TREE_VALUE (p1) == 0)
 537               {
 538                 TREE_VALUE (n) = TREE_VALUE (p2);
 539                 goto parm_done;
 540               }
 541             if (TREE_VALUE (p2) == 0)
 542               {
 543                 TREE_VALUE (n) = TREE_VALUE (p1);
 544                 goto parm_done;
 545               }
 546
 547             /* Given  wait (union {union wait *u; int *i} *)
 548                and  wait (union wait *),
 549                prefer  union wait *  as type of parm.  */
 550             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 551                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 552               {
 553                 tree memb;
 554                 tree mv2 = TREE_VALUE (p2);
 555                 if (mv2 && mv2 != error_mark_node
 556                     && TREE_CODE (mv2) != ARRAY_TYPE)
 557                   mv2 = TYPE_MAIN_VARIANT (mv2);
 558                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 559                      memb; memb = TREE_CHAIN (memb))
 560                   {
 561                     tree mv3 = TREE_TYPE (memb);
 562                     if (mv3 && mv3 != error_mark_node
 563                         && TREE_CODE (mv3) != ARRAY_TYPE)
 564                       mv3 = TYPE_MAIN_VARIANT (mv3);
 565                     if (comptypes (mv3, mv2))
 566                       {
 567                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 568                                                          TREE_VALUE (p2));
 569                         pedwarn (input_location, OPT_pedantic,
 570                                  "function types not truly compatible in ISO C");
 571                         goto parm_done;
 572                       }
 573                   }
 574               }
 575             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 576                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 577               {
 578                 tree memb;
 579                 tree mv1 = TREE_VALUE (p1);
 580                 if (mv1 && mv1 != error_mark_node
 581                     && TREE_CODE (mv1) != ARRAY_TYPE)
 582                   mv1 = TYPE_MAIN_VARIANT (mv1);
 583                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 584                      memb; memb = TREE_CHAIN (memb))
 585                   {
 586                     tree mv3 = TREE_TYPE (memb);
 587                     if (mv3 && mv3 != error_mark_node
 588                         && TREE_CODE (mv3) != ARRAY_TYPE)
 589                       mv3 = TYPE_MAIN_VARIANT (mv3);
 590                     if (comptypes (mv3, mv1))
 591                       {
 592                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 593                                                          TREE_VALUE (p1));
 594                         pedwarn (input_location, OPT_pedantic,
 595                                  "function types not truly compatible in ISO C");
 596                         goto parm_done;
 597                       }
 598                   }
 599               }
 600             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 601           parm_done: ;
 602           }
 603
 604         c_override_global_bindings_to_false = false;
 605         t1 = build_function_type (valtype, newargs);
 606         t1 = qualify_type (t1, t2);
 607         /* ... falls through ...  */
 608       }
 609
 610     default:
 611       return build_type_attribute_variant (t1, attributes);
 612     }
 613
 614 }
 615
 616 /* Return the type of a conditional expression between pointers to
 617    possibly differently qualified versions of compatible types.
 618
 619    We assume that comp_target_types has already been done and returned
 620    nonzero; if that isn't so, this may crash.  */
 621
 622 static tree
 623 common_pointer_type (tree t1, tree t2)
 624 {
 625   tree attributes;
 626   tree pointed_to_1, mv1;
 627   tree pointed_to_2, mv2;
 628   tree target;
 629   unsigned target_quals;
 630   addr_space_t as1, as2, as_common;
 631   int quals1, quals2;
 632
 633   /* Save time if the two types are the same.  */
 634
 635   if (t1 == t2) return t1;
 636
 637   /* If one type is nonsense, use the other.  */
 638   if (t1 == error_mark_node)
 639     return t2;
 640   if (t2 == error_mark_node)
 641     return t1;
 642
 643   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 644               && TREE_CODE (t2) == POINTER_TYPE);
 645
 646   /* Merge the attributes.  */
 647   attributes = targetm.merge_type_attributes (t1, t2);
 648
 649   /* Find the composite type of the target types, and combine the
 650      qualifiers of the two types' targets.  Do not lose qualifiers on
 651      array element types by taking the TYPE_MAIN_VARIANT.  */
 652   mv1 = pointed_to_1 = TREE_TYPE (t1);
 653   mv2 = pointed_to_2 = TREE_TYPE (t2);
 654   if (TREE_CODE (mv1) != ARRAY_TYPE)
 655     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 656   if (TREE_CODE (mv2) != ARRAY_TYPE)
 657     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 658   target = composite_type (mv1, mv2);
 659
 660   /* For function types do not merge const qualifiers, but drop them
 661      if used inconsistently.  The middle-end uses these to mark const
 662      and noreturn functions.  */
 663   quals1 = TYPE_QUALS_NO_ADDR_SPACE (pointed_to_1);
 664   quals2 = TYPE_QUALS_NO_ADDR_SPACE (pointed_to_2);
 665
 666   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 667     target_quals = (quals1 & quals2);
 668   else
 669     target_quals = (quals1 | quals2);
 670
 671   /* If the two named address spaces are different, determine the common
 672      superset address space.  This is guaranteed to exist due to the
 673      assumption that comp_target_type returned non-zero.  */
 674   as1 = TYPE_ADDR_SPACE (pointed_to_1);
 675   as2 = TYPE_ADDR_SPACE (pointed_to_2);
 676   if (!addr_space_superset (as1, as2, &as_common))
 677     gcc_unreachable ();
 678
 679   target_quals |= ENCODE_QUAL_ADDR_SPACE (as_common);
 680
 681   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 682   return build_type_attribute_variant (t1, attributes);
 683 }
 684
 685 /* Return the common type for two arithmetic types under the usual
 686    arithmetic conversions.  The default conversions have already been
 687    applied, and enumerated types converted to their compatible integer
 688    types.  The resulting type is unqualified and has no attributes.
 689
 690    This is the type for the result of most arithmetic operations
 691    if the operands have the given two types.  */
 692
 693 static tree
 694 c_common_type (tree t1, tree t2)
 695 {
 696   enum tree_code code1;
 697   enum tree_code code2;
 698
 699   /* If one type is nonsense, use the other.  */
 700   if (t1 == error_mark_node)
 701     return t2;
 702   if (t2 == error_mark_node)
 703     return t1;
 704
 705   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 706     t1 = TYPE_MAIN_VARIANT (t1);
 707
 708   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 709     t2 = TYPE_MAIN_VARIANT (t2);
 710
 711   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 712     t1 = build_type_attribute_variant (t1, NULL_TREE);
 713
 714   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 715     t2 = build_type_attribute_variant (t2, NULL_TREE);
 716
 717   /* Save time if the two types are the same.  */
 718
 719   if (t1 == t2) return t1;
 720
 721   code1 = TREE_CODE (t1);
 722   code2 = TREE_CODE (t2);
 723
 724   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 725               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 726               || code1 == INTEGER_TYPE);
 727   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 728               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 729               || code2 == INTEGER_TYPE);
 730
 731   /* When one operand is a decimal float type, the other operand cannot be
 732      a generic float type or a complex type.  We also disallow vector types
 733      here.  */
 734   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 735       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 736     {
 737       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 738         {
 739           error ("can%'t mix operands of decimal float and vector types");
 740           return error_mark_node;
 741         }
 742       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 743         {
 744           error ("can%'t mix operands of decimal float and complex types");
 745           return error_mark_node;
 746         }
 747       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 748         {
 749           error ("can%'t mix operands of decimal float and other float types");
 750           return error_mark_node;
 751         }
 752     }
 753
 754   /* If one type is a vector type, return that type.  (How the usual
 755      arithmetic conversions apply to the vector types extension is not
 756      precisely specified.)  */
 757   if (code1 == VECTOR_TYPE)
 758     return t1;
 759
 760   if (code2 == VECTOR_TYPE)
 761     return t2;
 762
 763   /* If one type is complex, form the common type of the non-complex
 764      components, then make that complex.  Use T1 or T2 if it is the
 765      required type.  */
 766   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 767     {
 768       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 769       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 770       tree subtype = c_common_type (subtype1, subtype2);
 771
 772       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 773         return t1;
 774       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 775         return t2;
 776       else
 777         return build_complex_type (subtype);
 778     }
 779
 780   /* If only one is real, use it as the result.  */
 781
 782   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 783     return t1;
 784
 785   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 786     return t2;
 787
 788   /* If both are real and either are decimal floating point types, use
 789      the decimal floating point type with the greater precision. */
 790
 791   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 792     {
 793       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 794           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 795         return dfloat128_type_node;
 796       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 797                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 798         return dfloat64_type_node;
 799       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 800                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 801         return dfloat32_type_node;
 802     }
 803
 804   /* Deal with fixed-point types.  */
 805   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 806     {
 807       unsigned int unsignedp = 0, satp = 0;
 808       enum machine_mode m1, m2;
 809       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 810
 811       m1 = TYPE_MODE (t1);
 812       m2 = TYPE_MODE (t2);
 813
 814       /* If one input type is saturating, the result type is saturating.  */
 815       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 816         satp = 1;
 817
 818       /* If both fixed-point types are unsigned, the result type is unsigned.
 819          When mixing fixed-point and integer types, follow the sign of the
 820          fixed-point type.
 821          Otherwise, the result type is signed.  */
 822       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 823            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 824           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 825               && TYPE_UNSIGNED (t1))
 826           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 827               && TYPE_UNSIGNED (t2)))
 828         unsignedp = 1;
 829
 830       /* The result type is signed.  */
 831       if (unsignedp == 0)
 832         {
 833           /* If the input type is unsigned, we need to convert to the
 834              signed type.  */
 835           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 836             {
 837               enum mode_class mclass = (enum mode_class) 0;
 838               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 839                 mclass = MODE_FRACT;
 840               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 841                 mclass = MODE_ACCUM;
 842               else
 843                 gcc_unreachable ();
 844               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 845             }
 846           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 847             {
 848               enum mode_class mclass = (enum mode_class) 0;
 849               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 850                 mclass = MODE_FRACT;
 851               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 852                 mclass = MODE_ACCUM;
 853               else
 854                 gcc_unreachable ();
 855               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 856             }
 857         }
 858
 859       if (code1 == FIXED_POINT_TYPE)
 860         {
 861           fbit1 = GET_MODE_FBIT (m1);
 862           ibit1 = GET_MODE_IBIT (m1);
 863         }
 864       else
 865         {
 866           fbit1 = 0;
 867           /* Signed integers need to subtract one sign bit.  */
 868           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 869         }
 870
 871       if (code2 == FIXED_POINT_TYPE)
 872         {
 873           fbit2 = GET_MODE_FBIT (m2);
 874           ibit2 = GET_MODE_IBIT (m2);
 875         }
 876       else
 877         {
 878           fbit2 = 0;
 879           /* Signed integers need to subtract one sign bit.  */
 880           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 881         }
 882
 883       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 884       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 885       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 886                                                  satp);
 887     }
 888
 889   /* Both real or both integers; use the one with greater precision.  */
 890
 891   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 892     return t1;
 893   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 894     return t2;
 895
 896   /* Same precision.  Prefer long longs to longs to ints when the
 897      same precision, following the C99 rules on integer type rank
 898      (which are equivalent to the C90 rules for C90 types).  */
 899
 900   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 901       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 902     return long_long_unsigned_type_node;
 903
 904   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 905       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 906     {
 907       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 908         return long_long_unsigned_type_node;
 909       else
 910         return long_long_integer_type_node;
 911     }
 912
 913   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 914       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 915     return long_unsigned_type_node;
 916
 917   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 918       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 919     {
 920       /* But preserve unsignedness from the other type,
 921          since long cannot hold all the values of an unsigned int.  */
 922       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 923         return long_unsigned_type_node;
 924       else
 925         return long_integer_type_node;
 926     }
 927
 928   /* Likewise, prefer long double to double even if same size.  */
 929   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 930       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 931     return long_double_type_node;
 932
 933   /* Otherwise prefer the unsigned one.  */
 934
 935   if (TYPE_UNSIGNED (t1))
 936     return t1;
 937   else
 938     return t2;
 939 }
 940 \f
 941 /* Wrapper around c_common_type that is used by c-common.c and other
 942    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 943    are allowed here and are converted to their compatible integer types.
 944    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 945    preferably a non-Boolean type as the common type.  */
 946 tree
 947 common_type (tree t1, tree t2)
 948 {
 949   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 950     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 951   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 952     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 953
 954   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 955   if (TREE_CODE (t1) == BOOLEAN_TYPE
 956       && TREE_CODE (t2) == BOOLEAN_TYPE)
 957     return boolean_type_node;
 958
 959   /* If either type is BOOLEAN_TYPE, then return the other.  */
 960   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 961     return t2;
 962   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 963     return t1;
 964
 965   return c_common_type (t1, t2);
 966 }
 967
 968 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 969    or various other operations.  Return 2 if they are compatible
 970    but a warning may be needed if you use them together.  */
 971
 972 int
 973 comptypes (tree type1, tree type2)
 974 {
 975   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 976   int val;
 977
 978   val = comptypes_internal (type1, type2, NULL);
 979   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 980
 981   return val;
 982 }
 983
 984 /* Like comptypes, but if it returns non-zero because enum and int are
 985    compatible, it sets *ENUM_AND_INT_P to true.  */
 986
 987 static int
 988 comptypes_check_enum_int (tree type1, tree type2, bool *enum_and_int_p)
 989 {
 990   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 991   int val;
 992
 993   val = comptypes_internal (type1, type2, enum_and_int_p);
 994   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 995
 996   return val;
 997 }
 998 \f
 999 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
1000    or various other operations.  Return 2 if they are compatible
1001    but a warning may be needed if you use them together.  If
1002    ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
1003    compatible integer type, then this sets *ENUM_AND_INT_P to true;
1004    *ENUM_AND_INT_P is never set to false.  This differs from
1005    comptypes, in that we don't free the seen types.  */
1006
1007 static int
1008 comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p)
1009 {
1010   const_tree t1 = type1;
1011   const_tree t2 = type2;
1012   int attrval, val;
1013
1014   /* Suppress errors caused by previously reported errors.  */
1015
1016   if (t1 == t2 || !t1 || !t2
1017       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
1018     return 1;
1019
1020   /* If either type is the internal version of sizetype, return the
1021      language version.  */
1022   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
1023       && TYPE_ORIG_SIZE_TYPE (t1))
1024     t1 = TYPE_ORIG_SIZE_TYPE (t1);
1025
1026   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
1027       && TYPE_ORIG_SIZE_TYPE (t2))
1028     t2 = TYPE_ORIG_SIZE_TYPE (t2);
1029
1030
1031   /* Enumerated types are compatible with integer types, but this is
1032      not transitive: two enumerated types in the same translation unit
1033      are compatible with each other only if they are the same type.  */
1034
1035   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
1036     {
1037       t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
1038       if (enum_and_int_p != NULL && TREE_CODE (t2) != VOID_TYPE)
1039         *enum_and_int_p = true;
1040     }
1041   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
1042     {
1043       t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
1044       if (enum_and_int_p != NULL && TREE_CODE (t1) != VOID_TYPE)
1045         *enum_and_int_p = true;
1046     }
1047
1048   if (t1 == t2)
1049     return 1;
1050
1051   /* Different classes of types can't be compatible.  */
1052
1053   if (TREE_CODE (t1) != TREE_CODE (t2))
1054     return 0;
1055
1056   /* Qualifiers must match. C99 6.7.3p9 */
1057
1058   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
1059     return 0;
1060
1061   /* Allow for two different type nodes which have essentially the same
1062      definition.  Note that we already checked for equality of the type
1063      qualifiers (just above).  */
1064
1065   if (TREE_CODE (t1) != ARRAY_TYPE
1066       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
1067     return 1;
1068
1069   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1070   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
1071      return 0;
1072
1073   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1074   val = 0;
1075
1076   switch (TREE_CODE (t1))
1077     {
1078     case POINTER_TYPE:
1079       /* Do not remove mode or aliasing information.  */
1080       if (TYPE_MODE (t1) != TYPE_MODE (t2)
1081           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
1082         break;
1083       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
1084              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1085                                        enum_and_int_p));
1086       break;
1087
1088     case FUNCTION_TYPE:
1089       val = function_types_compatible_p (t1, t2, enum_and_int_p);
1090       break;
1091
1092     case ARRAY_TYPE:
1093       {
1094         tree d1 = TYPE_DOMAIN (t1);
1095         tree d2 = TYPE_DOMAIN (t2);
1096         bool d1_variable, d2_variable;
1097         bool d1_zero, d2_zero;
1098         val = 1;
1099
1100         /* Target types must match incl. qualifiers.  */
1101         if (TREE_TYPE (t1) != TREE_TYPE (t2)
1102             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1103                                                enum_and_int_p)))
1104           return 0;
1105
1106         /* Sizes must match unless one is missing or variable.  */
1107         if (d1 == 0 || d2 == 0 || d1 == d2)
1108           break;
1109
1110         d1_zero = !TYPE_MAX_VALUE (d1);
1111         d2_zero = !TYPE_MAX_VALUE (d2);
1112
1113         d1_variable = (!d1_zero
1114                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
1115                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
1116         d2_variable = (!d2_zero
1117                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
1118                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
1119         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
1120         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
1121
1122         if (d1_variable || d2_variable)
1123           break;
1124         if (d1_zero && d2_zero)
1125           break;
1126         if (d1_zero || d2_zero
1127             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
1128             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
1129           val = 0;
1130
1131         break;
1132       }
1133
1134     case ENUMERAL_TYPE:
1135     case RECORD_TYPE:
1136     case UNION_TYPE:
1137       if (val != 1 && !same_translation_unit_p (t1, t2))
1138         {
1139           tree a1 = TYPE_ATTRIBUTES (t1);
1140           tree a2 = TYPE_ATTRIBUTES (t2);
1141
1142           if (! attribute_list_contained (a1, a2)
1143               && ! attribute_list_contained (a2, a1))
1144             break;
1145
1146           if (attrval != 2)
1147             return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1148           val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
1149         }
1150       break;
1151
1152     case VECTOR_TYPE:
1153       val = (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1154              && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
1155                                     enum_and_int_p));
1156       break;
1157
1158     default:
1159       break;
1160     }
1161   return attrval == 2 && val == 1 ? 2 : val;
1162 }
1163
1164 /* Return 1 if TTL and TTR are pointers to types that are equivalent, ignoring
1165    their qualifiers, except for named address spaces.  If the pointers point to
1166    different named addresses, then we must determine if one address space is a
1167    subset of the other.  */
1168
1169 static int
1170 comp_target_types (location_t location, tree ttl, tree ttr)
1171 {
1172   int val;
1173   tree mvl = TREE_TYPE (ttl);
1174   tree mvr = TREE_TYPE (ttr);
1175   addr_space_t asl = TYPE_ADDR_SPACE (mvl);
1176   addr_space_t asr = TYPE_ADDR_SPACE (mvr);
1177   addr_space_t as_common;
1178   bool enum_and_int_p;
1179
1180   /* Fail if pointers point to incompatible address spaces.  */
1181   if (!addr_space_superset (asl, asr, &as_common))
1182     return 0;
1183
1184   /* Do not lose qualifiers on element types of array types that are
1185      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1186   if (TREE_CODE (mvl) != ARRAY_TYPE)
1187     mvl = TYPE_MAIN_VARIANT (mvl);
1188   if (TREE_CODE (mvr) != ARRAY_TYPE)
1189     mvr = TYPE_MAIN_VARIANT (mvr);
1190   enum_and_int_p = false;
1191   val = comptypes_check_enum_int (mvl, mvr, &enum_and_int_p);
1192
1193   if (val == 2)
1194     pedwarn (location, OPT_pedantic, "types are not quite compatible");
1195
1196   if (val == 1 && enum_and_int_p && warn_cxx_compat)
1197     warning_at (location, OPT_Wc___compat,
1198                 "pointer target types incompatible in C++");
1199
1200   return val;
1201 }
1202 \f
1203 /* Subroutines of `comptypes'.  */
1204
1205 /* Determine whether two trees derive from the same translation unit.
1206    If the CONTEXT chain ends in a null, that tree's context is still
1207    being parsed, so if two trees have context chains ending in null,
1208    they're in the same translation unit.  */
1209 int
1210 same_translation_unit_p (const_tree t1, const_tree t2)
1211 {
1212   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1213     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1214       {
1215       case tcc_declaration:
1216         t1 = DECL_CONTEXT (t1); break;
1217       case tcc_type:
1218         t1 = TYPE_CONTEXT (t1); break;
1219       case tcc_exceptional:
1220         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1221       default: gcc_unreachable ();
1222       }
1223
1224   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1225     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1226       {
1227       case tcc_declaration:
1228         t2 = DECL_CONTEXT (t2); break;
1229       case tcc_type:
1230         t2 = TYPE_CONTEXT (t2); break;
1231       case tcc_exceptional:
1232         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1233       default: gcc_unreachable ();
1234       }
1235
1236   return t1 == t2;
1237 }
1238
1239 /* Allocate the seen two types, assuming that they are compatible. */
1240
1241 static struct tagged_tu_seen_cache *
1242 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1243 {
1244   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1245   tu->next = tagged_tu_seen_base;
1246   tu->t1 = t1;
1247   tu->t2 = t2;
1248
1249   tagged_tu_seen_base = tu;
1250
1251   /* The C standard says that two structures in different translation
1252      units are compatible with each other only if the types of their
1253      fields are compatible (among other things).  We assume that they
1254      are compatible until proven otherwise when building the cache.
1255      An example where this can occur is:
1256      struct a
1257      {
1258        struct a *next;
1259      };
1260      If we are comparing this against a similar struct in another TU,
1261      and did not assume they were compatible, we end up with an infinite
1262      loop.  */
1263   tu->val = 1;
1264   return tu;
1265 }
1266
1267 /* Free the seen types until we get to TU_TIL. */
1268
1269 static void
1270 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1271 {
1272   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1273   while (tu != tu_til)
1274     {
1275       const struct tagged_tu_seen_cache *const tu1
1276         = (const struct tagged_tu_seen_cache *) tu;
1277       tu = tu1->next;
1278       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1279     }
1280   tagged_tu_seen_base = tu_til;
1281 }
1282
1283 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1284    compatible.  If the two types are not the same (which has been
1285    checked earlier), this can only happen when multiple translation
1286    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1287    rules.  ENUM_AND_INT_P is as in comptypes_internal.  */
1288
1289 static int
1290 tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
1291                               bool *enum_and_int_p)
1292 {
1293   tree s1, s2;
1294   bool needs_warning = false;
1295
1296   /* We have to verify that the tags of the types are the same.  This
1297      is harder than it looks because this may be a typedef, so we have
1298      to go look at the original type.  It may even be a typedef of a
1299      typedef...
1300      In the case of compiler-created builtin structs the TYPE_DECL
1301      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1302   while (TYPE_NAME (t1)
1303          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1304          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1305     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1306
1307   while (TYPE_NAME (t2)
1308          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1309          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1310     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1311
1312   /* C90 didn't have the requirement that the two tags be the same.  */
1313   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1314     return 0;
1315
1316   /* C90 didn't say what happened if one or both of the types were
1317      incomplete; we choose to follow C99 rules here, which is that they
1318      are compatible.  */
1319   if (TYPE_SIZE (t1) == NULL
1320       || TYPE_SIZE (t2) == NULL)
1321     return 1;
1322
1323   {
1324     const struct tagged_tu_seen_cache * tts_i;
1325     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1326       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1327         return tts_i->val;
1328   }
1329
1330   switch (TREE_CODE (t1))
1331     {
1332     case ENUMERAL_TYPE:
1333       {
1334         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1335         /* Speed up the case where the type values are in the same order.  */
1336         tree tv1 = TYPE_VALUES (t1);
1337         tree tv2 = TYPE_VALUES (t2);
1338
1339         if (tv1 == tv2)
1340           {
1341             return 1;
1342           }
1343
1344         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1345           {
1346             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1347               break;
1348             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1349               {
1350                 tu->val = 0;
1351                 return 0;
1352               }
1353           }
1354
1355         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1356           {
1357             return 1;
1358           }
1359         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1360           {
1361             tu->val = 0;
1362             return 0;
1363           }
1364
1365         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1366           {
1367             tu->val = 0;
1368             return 0;
1369           }
1370
1371         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1372           {
1373             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1374             if (s2 == NULL
1375                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1376               {
1377                 tu->val = 0;
1378                 return 0;
1379               }
1380           }
1381         return 1;
1382       }
1383
1384     case UNION_TYPE:
1385       {
1386         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1387         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1388           {
1389             tu->val = 0;
1390             return 0;
1391           }
1392
1393         /*  Speed up the common case where the fields are in the same order. */
1394         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1395              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1396           {
1397             int result;
1398
1399             if (DECL_NAME (s1) != DECL_NAME (s2))
1400               break;
1401             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1402                                          enum_and_int_p);
1403
1404             if (result != 1 && !DECL_NAME (s1))
1405               break;
1406             if (result == 0)
1407               {
1408                 tu->val = 0;
1409                 return 0;
1410               }
1411             if (result == 2)
1412               needs_warning = true;
1413
1414             if (TREE_CODE (s1) == FIELD_DECL
1415                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1416                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1417               {
1418                 tu->val = 0;
1419                 return 0;
1420               }
1421           }
1422         if (!s1 && !s2)
1423           {
1424             tu->val = needs_warning ? 2 : 1;
1425             return tu->val;
1426           }
1427
1428         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1429           {
1430             bool ok = false;
1431
1432             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1433               if (DECL_NAME (s1) == DECL_NAME (s2))
1434                 {
1435                   int result;
1436
1437                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1438                                                enum_and_int_p);
1439
1440                   if (result != 1 && !DECL_NAME (s1))
1441                     continue;
1442                   if (result == 0)
1443                     {
1444                       tu->val = 0;
1445                       return 0;
1446                     }
1447                   if (result == 2)
1448                     needs_warning = true;
1449
1450                   if (TREE_CODE (s1) == FIELD_DECL
1451                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1452                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1453                     break;
1454
1455                   ok = true;
1456                   break;
1457                 }
1458             if (!ok)
1459               {
1460                 tu->val = 0;
1461                 return 0;
1462               }
1463           }
1464         tu->val = needs_warning ? 2 : 10;
1465         return tu->val;
1466       }
1467
1468     case RECORD_TYPE:
1469       {
1470         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1471
1472         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1473              s1 && s2;
1474              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1475           {
1476             int result;
1477             if (TREE_CODE (s1) != TREE_CODE (s2)
1478                 || DECL_NAME (s1) != DECL_NAME (s2))
1479               break;
1480             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
1481                                          enum_and_int_p);
1482             if (result == 0)
1483               break;
1484             if (result == 2)
1485               needs_warning = true;
1486
1487             if (TREE_CODE (s1) == FIELD_DECL
1488                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1489                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1490               break;
1491           }
1492         if (s1 && s2)
1493           tu->val = 0;
1494         else
1495           tu->val = needs_warning ? 2 : 1;
1496         return tu->val;
1497       }
1498
1499     default:
1500       gcc_unreachable ();
1501     }
1502 }
1503
1504 /* Return 1 if two function types F1 and F2 are compatible.
1505    If either type specifies no argument types,
1506    the other must specify a fixed number of self-promoting arg types.
1507    Otherwise, if one type specifies only the number of arguments,
1508    the other must specify that number of self-promoting arg types.
1509    Otherwise, the argument types must match.
1510    ENUM_AND_INT_P is as in comptypes_internal.  */
1511
1512 static int
1513 function_types_compatible_p (const_tree f1, const_tree f2,
1514                              bool *enum_and_int_p)
1515 {
1516   tree args1, args2;
1517   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1518   int val = 1;
1519   int val1;
1520   tree ret1, ret2;
1521
1522   ret1 = TREE_TYPE (f1);
1523   ret2 = TREE_TYPE (f2);
1524
1525   /* 'volatile' qualifiers on a function's return type used to mean
1526      the function is noreturn.  */
1527   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1528     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1529   if (TYPE_VOLATILE (ret1))
1530     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1531                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1532   if (TYPE_VOLATILE (ret2))
1533     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1534                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1535   val = comptypes_internal (ret1, ret2, enum_and_int_p);
1536   if (val == 0)
1537     return 0;
1538
1539   args1 = TYPE_ARG_TYPES (f1);
1540   args2 = TYPE_ARG_TYPES (f2);
1541
1542   /* An unspecified parmlist matches any specified parmlist
1543      whose argument types don't need default promotions.  */
1544
1545   if (args1 == 0)
1546     {
1547       if (!self_promoting_args_p (args2))
1548         return 0;
1549       /* If one of these types comes from a non-prototype fn definition,
1550          compare that with the other type's arglist.
1551          If they don't match, ask for a warning (but no error).  */
1552       if (TYPE_ACTUAL_ARG_TYPES (f1)
1553           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
1554                                            enum_and_int_p))
1555         val = 2;
1556       return val;
1557     }
1558   if (args2 == 0)
1559     {
1560       if (!self_promoting_args_p (args1))
1561         return 0;
1562       if (TYPE_ACTUAL_ARG_TYPES (f2)
1563           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
1564                                            enum_and_int_p))
1565         val = 2;
1566       return val;
1567     }
1568
1569   /* Both types have argument lists: compare them and propagate results.  */
1570   val1 = type_lists_compatible_p (args1, args2, enum_and_int_p);
1571   return val1 != 1 ? val1 : val;
1572 }
1573
1574 /* Check two lists of types for compatibility, returning 0 for
1575    incompatible, 1 for compatible, or 2 for compatible with
1576    warning.  ENUM_AND_INT_P is as in comptypes_internal.  */
1577
1578 static int
1579 type_lists_compatible_p (const_tree args1, const_tree args2,
1580                          bool *enum_and_int_p)
1581 {
1582   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1583   int val = 1;
1584   int newval = 0;
1585
1586   while (1)
1587     {
1588       tree a1, mv1, a2, mv2;
1589       if (args1 == 0 && args2 == 0)
1590         return val;
1591       /* If one list is shorter than the other,
1592          they fail to match.  */
1593       if (args1 == 0 || args2 == 0)
1594         return 0;
1595       mv1 = a1 = TREE_VALUE (args1);
1596       mv2 = a2 = TREE_VALUE (args2);
1597       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1598         mv1 = TYPE_MAIN_VARIANT (mv1);
1599       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1600         mv2 = TYPE_MAIN_VARIANT (mv2);
1601       /* A null pointer instead of a type
1602          means there is supposed to be an argument
1603          but nothing is specified about what type it has.
1604          So match anything that self-promotes.  */
1605       if (a1 == 0)
1606         {
1607           if (c_type_promotes_to (a2) != a2)
1608             return 0;
1609         }
1610       else if (a2 == 0)
1611         {
1612           if (c_type_promotes_to (a1) != a1)
1613             return 0;
1614         }
1615       /* If one of the lists has an error marker, ignore this arg.  */
1616       else if (TREE_CODE (a1) == ERROR_MARK
1617                || TREE_CODE (a2) == ERROR_MARK)
1618         ;
1619       else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p)))
1620         {
1621           /* Allow  wait (union {union wait *u; int *i} *)
1622              and  wait (union wait *)  to be compatible.  */
1623           if (TREE_CODE (a1) == UNION_TYPE
1624               && (TYPE_NAME (a1) == 0
1625                   || TYPE_TRANSPARENT_AGGR (a1))
1626               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1627               && tree_int_cst_equal (TYPE_SIZE (a1),
1628                                      TYPE_SIZE (a2)))
1629             {
1630               tree memb;
1631               for (memb = TYPE_FIELDS (a1);
1632                    memb; memb = TREE_CHAIN (memb))
1633                 {
1634                   tree mv3 = TREE_TYPE (memb);
1635                   if (mv3 && mv3 != error_mark_node
1636                       && TREE_CODE (mv3) != ARRAY_TYPE)
1637                     mv3 = TYPE_MAIN_VARIANT (mv3);
1638                   if (comptypes_internal (mv3, mv2, enum_and_int_p))
1639                     break;
1640                 }
1641               if (memb == 0)
1642                 return 0;
1643             }
1644           else if (TREE_CODE (a2) == UNION_TYPE
1645                    && (TYPE_NAME (a2) == 0
1646                        || TYPE_TRANSPARENT_AGGR (a2))
1647                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1648                    && tree_int_cst_equal (TYPE_SIZE (a2),
1649                                           TYPE_SIZE (a1)))
1650             {
1651               tree memb;
1652               for (memb = TYPE_FIELDS (a2);
1653                    memb; memb = TREE_CHAIN (memb))
1654                 {
1655                   tree mv3 = TREE_TYPE (memb);
1656                   if (mv3 && mv3 != error_mark_node
1657                       && TREE_CODE (mv3) != ARRAY_TYPE)
1658                     mv3 = TYPE_MAIN_VARIANT (mv3);
1659                   if (comptypes_internal (mv3, mv1, enum_and_int_p))
1660                     break;
1661                 }
1662               if (memb == 0)
1663                 return 0;
1664             }
1665           else
1666             return 0;
1667         }
1668
1669       /* comptypes said ok, but record if it said to warn.  */
1670       if (newval > val)
1671         val = newval;
1672
1673       args1 = TREE_CHAIN (args1);
1674       args2 = TREE_CHAIN (args2);
1675     }
1676 }
1677 \f
1678 /* Compute the size to increment a pointer by.  */
1679
1680 static tree
1681 c_size_in_bytes (const_tree type)
1682 {
1683   enum tree_code code = TREE_CODE (type);
1684
1685   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1686     return size_one_node;
1687
1688   if (!COMPLETE_OR_VOID_TYPE_P (type))
1689     {
1690       error ("arithmetic on pointer to an incomplete type");
1691       return size_one_node;
1692     }
1693
1694   /* Convert in case a char is more than one unit.  */
1695   return size_binop_loc (input_location, CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1696                          size_int (TYPE_PRECISION (char_type_node)
1697                                    / BITS_PER_UNIT));
1698 }
1699 \f
1700 /* Return either DECL or its known constant value (if it has one).  */
1701
1702 tree
1703 decl_constant_value (tree decl)
1704 {
1705   if (/* Don't change a variable array bound or initial value to a constant
1706          in a place where a variable is invalid.  Note that DECL_INITIAL
1707          isn't valid for a PARM_DECL.  */
1708       current_function_decl != 0
1709       && TREE_CODE (decl) != PARM_DECL
1710       && !TREE_THIS_VOLATILE (decl)
1711       && TREE_READONLY (decl)
1712       && DECL_INITIAL (decl) != 0
1713       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1714       /* This is invalid if initial value is not constant.
1715          If it has either a function call, a memory reference,
1716          or a variable, then re-evaluating it could give different results.  */
1717       && TREE_CONSTANT (DECL_INITIAL (decl))
1718       /* Check for cases where this is sub-optimal, even though valid.  */
1719       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1720     return DECL_INITIAL (decl);
1721   return decl;
1722 }
1723
1724 /* Convert the array expression EXP to a pointer.  */
1725 static tree
1726 array_to_pointer_conversion (location_t loc, tree exp)
1727 {
1728   tree orig_exp = exp;
1729   tree type = TREE_TYPE (exp);
1730   tree adr;
1731   tree restype = TREE_TYPE (type);
1732   tree ptrtype;
1733
1734   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1735
1736   STRIP_TYPE_NOPS (exp);
1737
1738   if (TREE_NO_WARNING (orig_exp))
1739     TREE_NO_WARNING (exp) = 1;
1740
1741   ptrtype = build_pointer_type (restype);
1742
1743   if (TREE_CODE (exp) == INDIRECT_REF)
1744     return convert (ptrtype, TREE_OPERAND (exp, 0));
1745
1746   adr = build_unary_op (loc, ADDR_EXPR, exp, 1);
1747   return convert (ptrtype, adr);
1748 }
1749
1750 /* Convert the function expression EXP to a pointer.  */
1751 static tree
1752 function_to_pointer_conversion (location_t loc, tree exp)
1753 {
1754   tree orig_exp = exp;
1755
1756   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1757
1758   STRIP_TYPE_NOPS (exp);
1759
1760   if (TREE_NO_WARNING (orig_exp))
1761     TREE_NO_WARNING (exp) = 1;
1762
1763   return build_unary_op (loc, ADDR_EXPR, exp, 0);
1764 }
1765
1766 /* Perform the default conversion of arrays and functions to pointers.
1767    Return the result of converting EXP.  For any other expression, just
1768    return EXP.
1769
1770    LOC is the location of the expression.  */
1771
1772 struct c_expr
1773 default_function_array_conversion (location_t loc, struct c_expr exp)
1774 {
1775   tree orig_exp = exp.value;
1776   tree type = TREE_TYPE (exp.value);
1777   enum tree_code code = TREE_CODE (type);
1778
1779   switch (code)
1780     {
1781     case ARRAY_TYPE:
1782       {
1783         bool not_lvalue = false;
1784         bool lvalue_array_p;
1785
1786         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1787                 || CONVERT_EXPR_P (exp.value))
1788                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1789           {
1790             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1791               not_lvalue = true;
1792             exp.value = TREE_OPERAND (exp.value, 0);
1793           }
1794
1795         if (TREE_NO_WARNING (orig_exp))
1796           TREE_NO_WARNING (exp.value) = 1;
1797
1798         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1799         if (!flag_isoc99 && !lvalue_array_p)
1800           {
1801             /* Before C99, non-lvalue arrays do not decay to pointers.
1802                Normally, using such an array would be invalid; but it can
1803                be used correctly inside sizeof or as a statement expression.
1804                Thus, do not give an error here; an error will result later.  */
1805             return exp;
1806           }
1807
1808         exp.value = array_to_pointer_conversion (loc, exp.value);
1809       }
1810       break;
1811     case FUNCTION_TYPE:
1812       exp.value = function_to_pointer_conversion (loc, exp.value);
1813       break;
1814     default:
1815       break;
1816     }
1817
1818   return exp;
1819 }
1820
1821
1822 /* EXP is an expression of integer type.  Apply the integer promotions
1823    to it and return the promoted value.  */
1824
1825 tree
1826 perform_integral_promotions (tree exp)
1827 {
1828   tree type = TREE_TYPE (exp);
1829   enum tree_code code = TREE_CODE (type);
1830
1831   gcc_assert (INTEGRAL_TYPE_P (type));
1832
1833   /* Normally convert enums to int,
1834      but convert wide enums to something wider.  */
1835   if (code == ENUMERAL_TYPE)
1836     {
1837       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1838                                           TYPE_PRECISION (integer_type_node)),
1839                                      ((TYPE_PRECISION (type)
1840                                        >= TYPE_PRECISION (integer_type_node))
1841                                       && TYPE_UNSIGNED (type)));
1842
1843       return convert (type, exp);
1844     }
1845
1846   /* ??? This should no longer be needed now bit-fields have their
1847      proper types.  */
1848   if (TREE_CODE (exp) == COMPONENT_REF
1849       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1850       /* If it's thinner than an int, promote it like a
1851          c_promoting_integer_type_p, otherwise leave it alone.  */
1852       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1853                                TYPE_PRECISION (integer_type_node)))
1854     return convert (integer_type_node, exp);
1855
1856   if (c_promoting_integer_type_p (type))
1857     {
1858       /* Preserve unsignedness if not really getting any wider.  */
1859       if (TYPE_UNSIGNED (type)
1860           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1861         return convert (unsigned_type_node, exp);
1862
1863       return convert (integer_type_node, exp);
1864     }
1865
1866   return exp;
1867 }
1868
1869
1870 /* Perform default promotions for C data used in expressions.
1871    Enumeral types or short or char are converted to int.
1872    In addition, manifest constants symbols are replaced by their values.  */
1873
1874 tree
1875 default_conversion (tree exp)
1876 {
1877   tree orig_exp;
1878   tree type = TREE_TYPE (exp);
1879   enum tree_code code = TREE_CODE (type);
1880   tree promoted_type;
1881
1882   /* Functions and arrays have been converted during parsing.  */
1883   gcc_assert (code != FUNCTION_TYPE);
1884   if (code == ARRAY_TYPE)
1885     return exp;
1886
1887   /* Constants can be used directly unless they're not loadable.  */
1888   if (TREE_CODE (exp) == CONST_DECL)
1889     exp = DECL_INITIAL (exp);
1890
1891   /* Strip no-op conversions.  */
1892   orig_exp = exp;
1893   STRIP_TYPE_NOPS (exp);
1894
1895   if (TREE_NO_WARNING (orig_exp))
1896     TREE_NO_WARNING (exp) = 1;
1897
1898   if (code == VOID_TYPE)
1899     {
1900       error ("void value not ignored as it ought to be");
1901       return error_mark_node;
1902     }
1903
1904   exp = require_complete_type (exp);
1905   if (exp == error_mark_node)
1906     return error_mark_node;
1907
1908   promoted_type = targetm.promoted_type (type);
1909   if (promoted_type)
1910     return convert (promoted_type, exp);
1911
1912   if (INTEGRAL_TYPE_P (type))
1913     return perform_integral_promotions (exp);
1914
1915   return exp;
1916 }
1917 \f
1918 /* Look up COMPONENT in a structure or union DECL.
1919
1920    If the component name is not found, returns NULL_TREE.  Otherwise,
1921    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1922    stepping down the chain to the component, which is in the last
1923    TREE_VALUE of the list.  Normally the list is of length one, but if
1924    the component is embedded within (nested) anonymous structures or
1925    unions, the list steps down the chain to the component.  */
1926
1927 static tree
1928 lookup_field (tree decl, tree component)
1929 {
1930   tree type = TREE_TYPE (decl);
1931   tree field;
1932
1933   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1934      to the field elements.  Use a binary search on this array to quickly
1935      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1936      will always be set for structures which have many elements.  */
1937
1938   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1939     {
1940       int bot, top, half;
1941       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1942
1943       field = TYPE_FIELDS (type);
1944       bot = 0;
1945       top = TYPE_LANG_SPECIFIC (type)->s->len;
1946       while (top - bot > 1)
1947         {
1948           half = (top - bot + 1) >> 1;
1949           field = field_array[bot+half];
1950
1951           if (DECL_NAME (field) == NULL_TREE)
1952             {
1953               /* Step through all anon unions in linear fashion.  */
1954               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1955                 {
1956                   field = field_array[bot++];
1957                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1958                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1959                     {
1960                       tree anon = lookup_field (field, component);
1961
1962                       if (anon)
1963                         return tree_cons (NULL_TREE, field, anon);
1964                     }
1965                 }
1966
1967               /* Entire record is only anon unions.  */
1968               if (bot > top)
1969                 return NULL_TREE;
1970
1971               /* Restart the binary search, with new lower bound.  */
1972               continue;
1973             }
1974
1975           if (DECL_NAME (field) == component)
1976             break;
1977           if (DECL_NAME (field) < component)
1978             bot += half;
1979           else
1980             top = bot + half;
1981         }
1982
1983       if (DECL_NAME (field_array[bot]) == component)
1984         field = field_array[bot];
1985       else if (DECL_NAME (field) != component)
1986         return NULL_TREE;
1987     }
1988   else
1989     {
1990       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1991         {
1992           if (DECL_NAME (field) == NULL_TREE
1993               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1994                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1995             {
1996               tree anon = lookup_field (field, component);
1997
1998               if (anon)
1999                 return tree_cons (NULL_TREE, field, anon);
2000             }
2001
2002           if (DECL_NAME (field) == component)
2003             break;
2004         }
2005
2006       if (field == NULL_TREE)
2007         return NULL_TREE;
2008     }
2009
2010   return tree_cons (NULL_TREE, field, NULL_TREE);
2011 }
2012
2013 /* Make an expression to refer to the COMPONENT field of structure or
2014    union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  LOC is the
2015    location of the COMPONENT_REF.  */
2016
2017 tree
2018 build_component_ref (location_t loc, tree datum, tree component)
2019 {
2020   tree type = TREE_TYPE (datum);
2021   enum tree_code code = TREE_CODE (type);
2022   tree field = NULL;
2023   tree ref;
2024   bool datum_lvalue = lvalue_p (datum);
2025
2026   if (!objc_is_public (datum, component))
2027     return error_mark_node;
2028
2029   /* See if there is a field or component with name COMPONENT.  */
2030
2031   if (code == RECORD_TYPE || code == UNION_TYPE)
2032     {
2033       if (!COMPLETE_TYPE_P (type))
2034         {
2035           c_incomplete_type_error (NULL_TREE, type);
2036           return error_mark_node;
2037         }
2038
2039       field = lookup_field (datum, component);
2040
2041       if (!field)
2042         {
2043           error_at (loc, "%qT has no member named %qE", type, component);
2044           return error_mark_node;
2045         }
2046
2047       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
2048          This might be better solved in future the way the C++ front
2049          end does it - by giving the anonymous entities each a
2050          separate name and type, and then have build_component_ref
2051          recursively call itself.  We can't do that here.  */
2052       do
2053         {
2054           tree subdatum = TREE_VALUE (field);
2055           int quals;
2056           tree subtype;
2057           bool use_datum_quals;
2058
2059           if (TREE_TYPE (subdatum) == error_mark_node)
2060             return error_mark_node;
2061
2062           /* If this is an rvalue, it does not have qualifiers in C
2063              standard terms and we must avoid propagating such
2064              qualifiers down to a non-lvalue array that is then
2065              converted to a pointer.  */
2066           use_datum_quals = (datum_lvalue
2067                              || TREE_CODE (TREE_TYPE (subdatum)) != ARRAY_TYPE);
2068
2069           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
2070           if (use_datum_quals)
2071             quals |= TYPE_QUALS (TREE_TYPE (datum));
2072           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
2073
2074           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
2075                         NULL_TREE);
2076           SET_EXPR_LOCATION (ref, loc);
2077           if (TREE_READONLY (subdatum)
2078               || (use_datum_quals && TREE_READONLY (datum)))
2079             TREE_READONLY (ref) = 1;
2080           if (TREE_THIS_VOLATILE (subdatum)
2081               || (use_datum_quals && TREE_THIS_VOLATILE (datum)))
2082             TREE_THIS_VOLATILE (ref) = 1;
2083
2084           if (TREE_DEPRECATED (subdatum))
2085             warn_deprecated_use (subdatum, NULL_TREE);
2086
2087           datum = ref;
2088
2089           field = TREE_CHAIN (field);
2090         }
2091       while (field);
2092
2093       return ref;
2094     }
2095   else if (code != ERROR_MARK)
2096     error_at (loc,
2097               "request for member %qE in something not a structure or union",
2098               component);
2099
2100   return error_mark_node;
2101 }
2102 \f
2103 /* Given an expression PTR for a pointer, return an expression
2104    for the value pointed to.
2105    ERRORSTRING is the name of the operator to appear in error messages.
2106
2107    LOC is the location to use for the generated tree.  */
2108
2109 tree
2110 build_indirect_ref (location_t loc, tree ptr, ref_operator errstring)
2111 {
2112   tree pointer = default_conversion (ptr);
2113   tree type = TREE_TYPE (pointer);
2114   tree ref;
2115
2116   if (TREE_CODE (type) == POINTER_TYPE)
2117     {
2118       if (CONVERT_EXPR_P (pointer)
2119           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
2120         {
2121           /* If a warning is issued, mark it to avoid duplicates from
2122              the backend.  This only needs to be done at
2123              warn_strict_aliasing > 2.  */
2124           if (warn_strict_aliasing > 2)
2125             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
2126                                          type, TREE_OPERAND (pointer, 0)))
2127               TREE_NO_WARNING (pointer) = 1;
2128         }
2129
2130       if (TREE_CODE (pointer) == ADDR_EXPR
2131           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
2132               == TREE_TYPE (type)))
2133         {
2134           ref = TREE_OPERAND (pointer, 0);
2135           protected_set_expr_location (ref, loc);
2136           return ref;
2137         }
2138       else
2139         {
2140           tree t = TREE_TYPE (type);
2141
2142           ref = build1 (INDIRECT_REF, t, pointer);
2143
2144           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2145             {
2146               error_at (loc, "dereferencing pointer to incomplete type");
2147               return error_mark_node;
2148             }
2149           if (VOID_TYPE_P (t) && c_inhibit_evaluation_warnings == 0)
2150             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2151
2152           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2153              so that we get the proper error message if the result is used
2154              to assign to.  Also, &* is supposed to be a no-op.
2155              And ANSI C seems to specify that the type of the result
2156              should be the const type.  */
2157           /* A de-reference of a pointer to const is not a const.  It is valid
2158              to change it via some other pointer.  */
2159           TREE_READONLY (ref) = TYPE_READONLY (t);
2160           TREE_SIDE_EFFECTS (ref)
2161             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2162           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2163           protected_set_expr_location (ref, loc);
2164           return ref;
2165         }
2166     }
2167   else if (TREE_CODE (pointer) != ERROR_MARK)
2168     switch (errstring)
2169       {
2170          case RO_ARRAY_INDEXING:
2171            error_at (loc,
2172                      "invalid type argument of array indexing (have %qT)",
2173                      type);
2174            break;
2175          case RO_UNARY_STAR:
2176            error_at (loc,
2177                      "invalid type argument of unary %<*%> (have %qT)",
2178                      type);
2179            break;
2180          case RO_ARROW:
2181            error_at (loc,
2182                      "invalid type argument of %<->%> (have %qT)",
2183                      type);
2184            break;
2185          default:
2186            gcc_unreachable ();
2187       }
2188   return error_mark_node;
2189 }
2190
2191 /* This handles expressions of the form "a[i]", which denotes
2192    an array reference.
2193
2194    This is logically equivalent in C to *(a+i), but we may do it differently.
2195    If A is a variable or a member, we generate a primitive ARRAY_REF.
2196    This avoids forcing the array out of registers, and can work on
2197    arrays that are not lvalues (for example, members of structures returned
2198    by functions).
2199
2200    LOC is the location to use for the returned expression.  */
2201
2202 tree
2203 build_array_ref (location_t loc, tree array, tree index)
2204 {
2205   tree ret;
2206   bool swapped = false;
2207   if (TREE_TYPE (array) == error_mark_node
2208       || TREE_TYPE (index) == error_mark_node)
2209     return error_mark_node;
2210
2211   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2212       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2213     {
2214       tree temp;
2215       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2216           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2217         {
2218           error_at (loc, "subscripted value is neither array nor pointer");
2219           return error_mark_node;
2220         }
2221       temp = array;
2222       array = index;
2223       index = temp;
2224       swapped = true;
2225     }
2226
2227   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2228     {
2229       error_at (loc, "array subscript is not an integer");
2230       return error_mark_node;
2231     }
2232
2233   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2234     {
2235       error_at (loc, "subscripted value is pointer to function");
2236       return error_mark_node;
2237     }
2238
2239   /* ??? Existing practice has been to warn only when the char
2240      index is syntactically the index, not for char[array].  */
2241   if (!swapped)
2242      warn_array_subscript_with_type_char (index);
2243
2244   /* Apply default promotions *after* noticing character types.  */
2245   index = default_conversion (index);
2246
2247   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2248
2249   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2250     {
2251       tree rval, type;
2252
2253       /* An array that is indexed by a non-constant
2254          cannot be stored in a register; we must be able to do
2255          address arithmetic on its address.
2256          Likewise an array of elements of variable size.  */
2257       if (TREE_CODE (index) != INTEGER_CST
2258           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2259               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2260         {
2261           if (!c_mark_addressable (array))
2262             return error_mark_node;
2263         }
2264       /* An array that is indexed by a constant value which is not within
2265          the array bounds cannot be stored in a register either; because we
2266          would get a crash in store_bit_field/extract_bit_field when trying
2267          to access a non-existent part of the register.  */
2268       if (TREE_CODE (index) == INTEGER_CST
2269           && TYPE_DOMAIN (TREE_TYPE (array))
2270           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2271         {
2272           if (!c_mark_addressable (array))
2273             return error_mark_node;
2274         }
2275
2276       if (pedantic)
2277         {
2278           tree foo = array;
2279           while (TREE_CODE (foo) == COMPONENT_REF)
2280             foo = TREE_OPERAND (foo, 0);
2281           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2282             pedwarn (loc, OPT_pedantic,
2283                      "ISO C forbids subscripting %<register%> array");
2284           else if (!flag_isoc99 && !lvalue_p (foo))
2285             pedwarn (loc, OPT_pedantic,
2286                      "ISO C90 forbids subscripting non-lvalue array");
2287         }
2288
2289       type = TREE_TYPE (TREE_TYPE (array));
2290       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2291       /* Array ref is const/volatile if the array elements are
2292          or if the array is.  */
2293       TREE_READONLY (rval)
2294         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2295             | TREE_READONLY (array));
2296       TREE_SIDE_EFFECTS (rval)
2297         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2298             | TREE_SIDE_EFFECTS (array));
2299       TREE_THIS_VOLATILE (rval)
2300         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2301             /* This was added by rms on 16 Nov 91.
2302                It fixes  vol struct foo *a;  a->elts[1]
2303                in an inline function.
2304                Hope it doesn't break something else.  */
2305             | TREE_THIS_VOLATILE (array));
2306       ret = require_complete_type (rval);
2307       protected_set_expr_location (ret, loc);
2308       return ret;
2309     }
2310   else
2311     {
2312       tree ar = default_conversion (array);
2313
2314       if (ar == error_mark_node)
2315         return ar;
2316
2317       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2318       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2319
2320       return build_indirect_ref
2321         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2322          RO_ARRAY_INDEXING);
2323     }
2324 }
2325 \f
2326 /* Build an external reference to identifier ID.  FUN indicates
2327    whether this will be used for a function call.  LOC is the source
2328    location of the identifier.  This sets *TYPE to the type of the
2329    identifier, which is not the same as the type of the returned value
2330    for CONST_DECLs defined as enum constants.  If the type of the
2331    identifier is not available, *TYPE is set to NULL.  */
2332 tree
2333 build_external_ref (location_t loc, tree id, int fun, tree *type)
2334 {
2335   tree ref;
2336   tree decl = lookup_name (id);
2337
2338   /* In Objective-C, an instance variable (ivar) may be preferred to
2339      whatever lookup_name() found.  */
2340   decl = objc_lookup_ivar (decl, id);
2341
2342   *type = NULL;
2343   if (decl && decl != error_mark_node)
2344     {
2345       ref = decl;
2346       *type = TREE_TYPE (ref);
2347     }
2348   else if (fun)
2349     /* Implicit function declaration.  */
2350     ref = implicitly_declare (loc, id);
2351   else if (decl == error_mark_node)
2352     /* Don't complain about something that's already been
2353        complained about.  */
2354     return error_mark_node;
2355   else
2356     {
2357       undeclared_variable (loc, id);
2358       return error_mark_node;
2359     }
2360
2361   if (TREE_TYPE (ref) == error_mark_node)
2362     return error_mark_node;
2363
2364   if (TREE_DEPRECATED (ref))
2365     warn_deprecated_use (ref, NULL_TREE);
2366
2367   /* Recursive call does not count as usage.  */
2368   if (ref != current_function_decl)
2369     {
2370       TREE_USED (ref) = 1;
2371     }
2372
2373   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2374     {
2375       if (!in_sizeof && !in_typeof)
2376         C_DECL_USED (ref) = 1;
2377       else if (DECL_INITIAL (ref) == 0
2378                && DECL_EXTERNAL (ref)
2379                && !TREE_PUBLIC (ref))
2380         record_maybe_used_decl (ref);
2381     }
2382
2383   if (TREE_CODE (ref) == CONST_DECL)
2384     {
2385       used_types_insert (TREE_TYPE (ref));
2386
2387       if (warn_cxx_compat
2388           && TREE_CODE (TREE_TYPE (ref)) == ENUMERAL_TYPE
2389           && C_TYPE_DEFINED_IN_STRUCT (TREE_TYPE (ref)))
2390         {
2391           warning_at (loc, OPT_Wc___compat,
2392                       ("enum constant defined in struct or union "
2393                        "is not visible in C++"));
2394           inform (DECL_SOURCE_LOCATION (ref), "enum constant defined here");
2395         }
2396
2397       ref = DECL_INITIAL (ref);
2398       TREE_CONSTANT (ref) = 1;
2399     }
2400   else if (current_function_decl != 0
2401            && !DECL_FILE_SCOPE_P (current_function_decl)
2402            && (TREE_CODE (ref) == VAR_DECL
2403                || TREE_CODE (ref) == PARM_DECL
2404                || TREE_CODE (ref) == FUNCTION_DECL))
2405     {
2406       tree context = decl_function_context (ref);
2407
2408       if (context != 0 && context != current_function_decl)
2409         DECL_NONLOCAL (ref) = 1;
2410     }
2411   /* C99 6.7.4p3: An inline definition of a function with external
2412      linkage ... shall not contain a reference to an identifier with
2413      internal linkage.  */
2414   else if (current_function_decl != 0
2415            && DECL_DECLARED_INLINE_P (current_function_decl)
2416            && DECL_EXTERNAL (current_function_decl)
2417            && VAR_OR_FUNCTION_DECL_P (ref)
2418            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2419            && ! TREE_PUBLIC (ref)
2420            && DECL_CONTEXT (ref) != current_function_decl)
2421     record_inline_static (loc, current_function_decl, ref,
2422                           csi_internal);
2423
2424   return ref;
2425 }
2426
2427 /* Record details of decls possibly used inside sizeof or typeof.  */
2428 struct maybe_used_decl
2429 {
2430   /* The decl.  */
2431   tree decl;
2432   /* The level seen at (in_sizeof + in_typeof).  */
2433   int level;
2434   /* The next one at this level or above, or NULL.  */
2435   struct maybe_used_decl *next;
2436 };
2437
2438 static struct maybe_used_decl *maybe_used_decls;
2439
2440 /* Record that DECL, an undefined static function reference seen
2441    inside sizeof or typeof, might be used if the operand of sizeof is
2442    a VLA type or the operand of typeof is a variably modified
2443    type.  */
2444
2445 static void
2446 record_maybe_used_decl (tree decl)
2447 {
2448   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2449   t->decl = decl;
2450   t->level = in_sizeof + in_typeof;
2451   t->next = maybe_used_decls;
2452   maybe_used_decls = t;
2453 }
2454
2455 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2456    USED is false, just discard them.  If it is true, mark them used
2457    (if no longer inside sizeof or typeof) or move them to the next
2458    level up (if still inside sizeof or typeof).  */
2459
2460 void
2461 pop_maybe_used (bool used)
2462 {
2463   struct maybe_used_decl *p = maybe_used_decls;
2464   int cur_level = in_sizeof + in_typeof;
2465   while (p && p->level > cur_level)
2466     {
2467       if (used)
2468         {
2469           if (cur_level == 0)
2470             C_DECL_USED (p->decl) = 1;
2471           else
2472             p->level = cur_level;
2473         }
2474       p = p->next;
2475     }
2476   if (!used || cur_level == 0)
2477     maybe_used_decls = p;
2478 }
2479
2480 /* Return the result of sizeof applied to EXPR.  */
2481
2482 struct c_expr
2483 c_expr_sizeof_expr (location_t loc, struct c_expr expr)
2484 {
2485   struct c_expr ret;
2486   if (expr.value == error_mark_node)
2487     {
2488       ret.value = error_mark_node;
2489       ret.original_code = ERROR_MARK;
2490       ret.original_type = NULL;
2491       pop_maybe_used (false);
2492     }
2493   else
2494     {
2495       bool expr_const_operands = true;
2496       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
2497                                        &expr_const_operands);
2498       ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));
2499       ret.original_code = ERROR_MARK;
2500       ret.original_type = NULL;
2501       if (c_vla_type_p (TREE_TYPE (folded_expr)))
2502         {
2503           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2504           ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2505                               folded_expr, ret.value);
2506           C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands;
2507           SET_EXPR_LOCATION (ret.value, loc);
2508         }
2509       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (folded_expr)));
2510     }
2511   return ret;
2512 }
2513
2514 /* Return the result of sizeof applied to T, a structure for the type
2515    name passed to sizeof (rather than the type itself).  LOC is the
2516    location of the original expression.  */
2517
2518 struct c_expr
2519 c_expr_sizeof_type (location_t loc, struct c_type_name *t)
2520 {
2521   tree type;
2522   struct c_expr ret;
2523   tree type_expr = NULL_TREE;
2524   bool type_expr_const = true;
2525   type = groktypename (t, &type_expr, &type_expr_const);
2526   ret.value = c_sizeof (loc, type);
2527   ret.original_code = ERROR_MARK;
2528   ret.original_type = NULL;
2529   if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST)
2530       && c_vla_type_p (type))
2531     {
2532       /* If the type is a [*] array, it is a VLA but is represented as
2533          having a size of zero.  In such a case we must ensure that
2534          the result of sizeof does not get folded to a constant by
2535          c_fully_fold, because if the size is evaluated the result is
2536          not constant and so constraints on zero or negative size
2537          arrays must not be applied when this sizeof call is inside
2538          another array declarator.  */
2539       if (!type_expr)
2540         type_expr = integer_zero_node;
2541       ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value),
2542                           type_expr, ret.value);
2543       C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const;
2544     }
2545   pop_maybe_used (type != error_mark_node
2546                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2547   return ret;
2548 }
2549
2550 /* Build a function call to function FUNCTION with parameters PARAMS.
2551    The function call is at LOC.
2552    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2553    TREE_VALUE of each node is a parameter-expression.
2554    FUNCTION's data type may be a function type or a pointer-to-function.  */
2555
2556 tree
2557 build_function_call (location_t loc, tree function, tree params)
2558 {
2559   VEC(tree,gc) *vec;
2560   tree ret;
2561
2562   vec = VEC_alloc (tree, gc, list_length (params));
2563   for (; params; params = TREE_CHAIN (params))
2564     VEC_quick_push (tree, vec, TREE_VALUE (params));
2565   ret = build_function_call_vec (loc, function, vec, NULL);
2566   VEC_free (tree, gc, vec);
2567   return ret;
2568 }
2569
2570 /* Build a function call to function FUNCTION with parameters PARAMS.
2571    ORIGTYPES, if not NULL, is a vector of types; each element is
2572    either NULL or the original type of the corresponding element in
2573    PARAMS.  The original type may differ from TREE_TYPE of the
2574    parameter for enums.  FUNCTION's data type may be a function type
2575    or pointer-to-function.  This function changes the elements of
2576    PARAMS.  */
2577
2578 tree
2579 build_function_call_vec (location_t loc, tree function, VEC(tree,gc) *params,
2580                          VEC(tree,gc) *origtypes)
2581 {
2582   tree fntype, fundecl = 0;
2583   tree name = NULL_TREE, result;
2584   tree tem;
2585   int nargs;
2586   tree *argarray;
2587
2588
2589   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2590   STRIP_TYPE_NOPS (function);
2591
2592   /* Convert anything with function type to a pointer-to-function.  */
2593   if (TREE_CODE (function) == FUNCTION_DECL)
2594     {
2595       /* Implement type-directed function overloading for builtins.
2596          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2597          handle all the type checking.  The result is a complete expression
2598          that implements this function call.  */
2599       tem = resolve_overloaded_builtin (loc, function, params);
2600       if (tem)
2601         return tem;
2602
2603       name = DECL_NAME (function);
2604       fundecl = function;
2605     }
2606   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2607     function = function_to_pointer_conversion (loc, function);
2608
2609   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2610      expressions, like those used for ObjC messenger dispatches.  */
2611   if (!VEC_empty (tree, params))
2612     function = objc_rewrite_function_call (function,
2613                                            VEC_index (tree, params, 0));
2614
2615   function = c_fully_fold (function, false, NULL);
2616
2617   fntype = TREE_TYPE (function);
2618
2619   if (TREE_CODE (fntype) == ERROR_MARK)
2620     return error_mark_node;
2621
2622   if (!(TREE_CODE (fntype) == POINTER_TYPE
2623         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2624     {
2625       error_at (loc, "called object %qE is not a function", function);
2626       return error_mark_node;
2627     }
2628
2629   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2630     current_function_returns_abnormally = 1;
2631
2632   /* fntype now gets the type of function pointed to.  */
2633   fntype = TREE_TYPE (fntype);
2634
2635   /* Convert the parameters to the types declared in the
2636      function prototype, or apply default promotions.  */
2637
2638   nargs = convert_arguments (TYPE_ARG_TYPES (fntype), params, origtypes,
2639                              function, fundecl);
2640   if (nargs < 0)
2641     return error_mark_node;
2642
2643   /* Check that the function is called through a compatible prototype.
2644      If it is not, replace the call by a trap, wrapped up in a compound
2645      expression if necessary.  This has the nice side-effect to prevent
2646      the tree-inliner from generating invalid assignment trees which may
2647      blow up in the RTL expander later.  */
2648   if (CONVERT_EXPR_P (function)
2649       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2650       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2651       && !comptypes (fntype, TREE_TYPE (tem)))
2652     {
2653       tree return_type = TREE_TYPE (fntype);
2654       tree trap = build_function_call (loc, built_in_decls[BUILT_IN_TRAP],
2655                                        NULL_TREE);
2656       int i;
2657
2658       /* This situation leads to run-time undefined behavior.  We can't,
2659          therefore, simply error unless we can prove that all possible
2660          executions of the program must execute the code.  */
2661       if (warning_at (loc, 0, "function called through a non-compatible type"))
2662         /* We can, however, treat "undefined" any way we please.
2663            Call abort to encourage the user to fix the program.  */
2664         inform (loc, "if this code is reached, the program will abort");
2665       /* Before the abort, allow the function arguments to exit or
2666          call longjmp.  */
2667       for (i = 0; i < nargs; i++)
2668         trap = build2 (COMPOUND_EXPR, void_type_node,
2669                        VEC_index (tree, params, i), trap);
2670
2671       if (VOID_TYPE_P (return_type))
2672         {
2673           if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
2674             pedwarn (loc, 0,
2675                      "function with qualified void return type called");
2676           return trap;
2677         }
2678       else
2679         {
2680           tree rhs;
2681
2682           if (AGGREGATE_TYPE_P (return_type))
2683             rhs = build_compound_literal (loc, return_type,
2684                                           build_constructor (return_type, 0),
2685                                           false);
2686           else
2687             rhs = fold_convert_loc (loc, return_type, integer_zero_node);
2688
2689           return require_complete_type (build2 (COMPOUND_EXPR, return_type,
2690                                                 trap, rhs));
2691         }
2692     }
2693
2694   argarray = VEC_address (tree, params);
2695
2696   /* Check that arguments to builtin functions match the expectations.  */
2697   if (fundecl
2698       && DECL_BUILT_IN (fundecl)
2699       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2700       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2701     return error_mark_node;
2702
2703   /* Check that the arguments to the function are valid.  */
2704   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2705                             TYPE_ARG_TYPES (fntype));
2706
2707   if (name != NULL_TREE
2708       && !strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10))
2709     {
2710       if (require_constant_value)
2711         result =
2712           fold_build_call_array_initializer_loc (loc, TREE_TYPE (fntype),
2713                                                  function, nargs, argarray);
2714       else
2715         result = fold_build_call_array_loc (loc, TREE_TYPE (fntype),
2716                                             function, nargs, argarray);
2717       if (TREE_CODE (result) == NOP_EXPR
2718           && TREE_CODE (TREE_OPERAND (result, 0)) == INTEGER_CST)
2719         STRIP_TYPE_NOPS (result);
2720     }
2721   else
2722     result = build_call_array_loc (loc, TREE_TYPE (fntype),
2723                                    function, nargs, argarray);
2724
2725   if (VOID_TYPE_P (TREE_TYPE (result)))
2726     {
2727       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)
2728         pedwarn (loc, 0,
2729                  "function with qualified void return type called");
2730       return result;
2731     }
2732   return require_complete_type (result);
2733 }
2734 \f
2735 /* Convert the argument expressions in the vector VALUES
2736    to the types in the list TYPELIST.
2737
2738    If TYPELIST is exhausted, or when an element has NULL as its type,
2739    perform the default conversions.
2740
2741    ORIGTYPES is the original types of the expressions in VALUES.  This
2742    holds the type of enum values which have been converted to integral
2743    types.  It may be NULL.
2744
2745    FUNCTION is a tree for the called function.  It is used only for
2746    error messages, where it is formatted with %qE.
2747
2748    This is also where warnings about wrong number of args are generated.
2749
2750    Returns the actual number of arguments processed (which may be less
2751    than the length of VALUES in some error situations), or -1 on
2752    failure.  */
2753
2754 static int
2755 convert_arguments (tree typelist, VEC(tree,gc) *values,
2756                    VEC(tree,gc) *origtypes, tree function, tree fundecl)
2757 {
2758   tree typetail, val;
2759   unsigned int parmnum;
2760   bool error_args = false;
2761   const bool type_generic = fundecl
2762     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2763   bool type_generic_remove_excess_precision = false;
2764   tree selector;
2765
2766   /* Change pointer to function to the function itself for
2767      diagnostics.  */
2768   if (TREE_CODE (function) == ADDR_EXPR
2769       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2770     function = TREE_OPERAND (function, 0);
2771
2772   /* Handle an ObjC selector specially for diagnostics.  */
2773   selector = objc_message_selector ();
2774
2775   /* For type-generic built-in functions, determine whether excess
2776      precision should be removed (classification) or not
2777      (comparison).  */
2778   if (type_generic
2779       && DECL_BUILT_IN (fundecl)
2780       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL)
2781     {
2782       switch (DECL_FUNCTION_CODE (fundecl))
2783         {
2784         case BUILT_IN_ISFINITE:
2785         case BUILT_IN_ISINF:
2786         case BUILT_IN_ISINF_SIGN:
2787         case BUILT_IN_ISNAN:
2788         case BUILT_IN_ISNORMAL:
2789         case BUILT_IN_FPCLASSIFY:
2790           type_generic_remove_excess_precision = true;
2791           break;
2792
2793         default:
2794           type_generic_remove_excess_precision = false;
2795           break;
2796         }
2797     }
2798
2799   /* Scan the given expressions and types, producing individual
2800      converted arguments.  */
2801
2802   for (typetail = typelist, parmnum = 0;
2803        VEC_iterate (tree, values, parmnum, val);
2804        ++parmnum)
2805     {
2806       tree type = typetail ? TREE_VALUE (typetail) : 0;
2807       tree valtype = TREE_TYPE (val);
2808       tree rname = function;
2809       int argnum = parmnum + 1;
2810       const char *invalid_func_diag;
2811       bool excess_precision = false;
2812       bool npc;
2813       tree parmval;
2814
2815       if (type == void_type_node)
2816         {
2817           error ("too many arguments to function %qE", function);
2818           return parmnum;
2819         }
2820
2821       if (selector && argnum > 2)
2822         {
2823           rname = selector;
2824           argnum -= 2;
2825         }
2826
2827       npc = null_pointer_constant_p (val);
2828
2829       /* If there is excess precision and a prototype, convert once to
2830          the required type rather than converting via the semantic
2831          type.  Likewise without a prototype a float value represented
2832          as long double should be converted once to double.  But for
2833          type-generic classification functions excess precision must
2834          be removed here.  */
2835       if (TREE_CODE (val) == EXCESS_PRECISION_EXPR
2836           && (type || !type_generic || !type_generic_remove_excess_precision))
2837         {
2838           val = TREE_OPERAND (val, 0);
2839           excess_precision = true;
2840         }
2841       val = c_fully_fold (val, false, NULL);
2842       STRIP_TYPE_NOPS (val);
2843
2844       val = require_complete_type (val);
2845
2846       if (type != 0)
2847         {
2848           /* Formal parm type is specified by a function prototype.  */
2849
2850           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2851             {
2852               error ("type of formal parameter %d is incomplete", parmnum + 1);
2853               parmval = val;
2854             }
2855           else
2856             {
2857               tree origtype;
2858
2859               /* Optionally warn about conversions that
2860                  differ from the default conversions.  */
2861               if (warn_traditional_conversion || warn_traditional)
2862                 {
2863                   unsigned int formal_prec = TYPE_PRECISION (type);
2864
2865                   if (INTEGRAL_TYPE_P (type)
2866                       && TREE_CODE (valtype) == REAL_TYPE)
2867                     warning (0, "passing argument %d of %qE as integer "
2868                              "rather than floating due to prototype",
2869                              argnum, rname);
2870                   if (INTEGRAL_TYPE_P (type)
2871                       && TREE_CODE (valtype) == COMPLEX_TYPE)
2872                     warning (0, "passing argument %d of %qE as integer "
2873                              "rather than complex due to prototype",
2874                              argnum, rname);
2875                   else if (TREE_CODE (type) == COMPLEX_TYPE
2876                            && TREE_CODE (valtype) == REAL_TYPE)
2877                     warning (0, "passing argument %d of %qE as complex "
2878                              "rather than floating due to prototype",
2879                              argnum, rname);
2880                   else if (TREE_CODE (type) == REAL_TYPE
2881                            && INTEGRAL_TYPE_P (valtype))
2882                     warning (0, "passing argument %d of %qE as floating "
2883                              "rather than integer due to prototype",
2884                              argnum, rname);
2885                   else if (TREE_CODE (type) == COMPLEX_TYPE
2886                            && INTEGRAL_TYPE_P (valtype))
2887                     warning (0, "passing argument %d of %qE as complex "
2888                              "rather than integer due to prototype",
2889                              argnum, rname);
2890                   else if (TREE_CODE (type) == REAL_TYPE
2891                            && TREE_CODE (valtype) == COMPLEX_TYPE)
2892                     warning (0, "passing argument %d of %qE as floating "
2893                              "rather than complex due to prototype",
2894                              argnum, rname);
2895                   /* ??? At some point, messages should be written about
2896                      conversions between complex types, but that's too messy
2897                      to do now.  */
2898                   else if (TREE_CODE (type) == REAL_TYPE
2899                            && TREE_CODE (valtype) == REAL_TYPE)
2900                     {
2901                       /* Warn if any argument is passed as `float',
2902                          since without a prototype it would be `double'.  */
2903                       if (formal_prec == TYPE_PRECISION (float_type_node)
2904                           && type != dfloat32_type_node)
2905                         warning (0, "passing argument %d of %qE as %<float%> "
2906                                  "rather than %<double%> due to prototype",
2907                                  argnum, rname);
2908
2909                       /* Warn if mismatch between argument and prototype
2910                          for decimal float types.  Warn of conversions with
2911                          binary float types and of precision narrowing due to
2912                          prototype. */
2913                       else if (type != valtype
2914                                && (type == dfloat32_type_node
2915                                    || type == dfloat64_type_node
2916                                    || type == dfloat128_type_node
2917                                    || valtype == dfloat32_type_node
2918                                    || valtype == dfloat64_type_node
2919                                    || valtype == dfloat128_type_node)
2920                                && (formal_prec
2921                                    <= TYPE_PRECISION (valtype)
2922                                    || (type == dfloat128_type_node
2923                                        && (valtype
2924                                            != dfloat64_type_node
2925                                            && (valtype
2926                                                != dfloat32_type_node)))
2927                                    || (type == dfloat64_type_node
2928                                        && (valtype
2929                                            != dfloat32_type_node))))
2930                         warning (0, "passing argument %d of %qE as %qT "
2931                                  "rather than %qT due to prototype",
2932                                  argnum, rname, type, valtype);
2933
2934                     }
2935                   /* Detect integer changing in width or signedness.
2936                      These warnings are only activated with
2937                      -Wtraditional-conversion, not with -Wtraditional.  */
2938                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2939                            && INTEGRAL_TYPE_P (valtype))
2940                     {
2941                       tree would_have_been = default_conversion (val);
2942                       tree type1 = TREE_TYPE (would_have_been);
2943
2944                       if (TREE_CODE (type) == ENUMERAL_TYPE
2945                           && (TYPE_MAIN_VARIANT (type)
2946                               == TYPE_MAIN_VARIANT (valtype)))
2947                         /* No warning if function asks for enum
2948                            and the actual arg is that enum type.  */
2949                         ;
2950                       else if (formal_prec != TYPE_PRECISION (type1))
2951                         warning (OPT_Wtraditional_conversion,
2952                                  "passing argument %d of %qE "
2953                                  "with different width due to prototype",
2954                                  argnum, rname);
2955                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2956                         ;
2957                       /* Don't complain if the formal parameter type
2958                          is an enum, because we can't tell now whether
2959                          the value was an enum--even the same enum.  */
2960                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2961                         ;
2962                       else if (TREE_CODE (val) == INTEGER_CST
2963                                && int_fits_type_p (val, type))
2964                         /* Change in signedness doesn't matter
2965                            if a constant value is unaffected.  */
2966                         ;
2967                       /* If the value is extended from a narrower
2968                          unsigned type, it doesn't matter whether we
2969                          pass it as signed or unsigned; the value
2970                          certainly is the same either way.  */
2971                       else if (TYPE_PRECISION (valtype) < TYPE_PRECISION (type)
2972                                && TYPE_UNSIGNED (valtype))
2973                         ;
2974                       else if (TYPE_UNSIGNED (type))
2975                         warning (OPT_Wtraditional_conversion,
2976                                  "passing argument %d of %qE "
2977                                  "as unsigned due to prototype",
2978                                  argnum, rname);
2979                       else
2980                         warning (OPT_Wtraditional_conversion,
2981                                  "passing argument %d of %qE "
2982                                  "as signed due to prototype", argnum, rname);
2983                     }
2984                 }
2985
2986               /* Possibly restore an EXCESS_PRECISION_EXPR for the
2987                  sake of better warnings from convert_and_check.  */
2988               if (excess_precision)
2989                 val = build1 (EXCESS_PRECISION_EXPR, valtype, val);
2990               origtype = (origtypes == NULL
2991                           ? NULL_TREE
2992                           : VEC_index (tree, origtypes, parmnum));
2993               parmval = convert_for_assignment (input_location, type, val,
2994                                                 origtype, ic_argpass, npc,
2995                                                 fundecl, function,
2996                                                 parmnum + 1);
2997
2998               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2999                   && INTEGRAL_TYPE_P (type)
3000                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
3001                 parmval = default_conversion (parmval);
3002             }
3003         }
3004       else if (TREE_CODE (valtype) == REAL_TYPE
3005                && (TYPE_PRECISION (valtype)
3006                    < TYPE_PRECISION (double_type_node))
3007                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (valtype)))
3008         {
3009           if (type_generic)
3010             parmval = val;
3011           else
3012             /* Convert `float' to `double'.  */
3013             parmval = convert (double_type_node, val);
3014         }
3015       else if (excess_precision && !type_generic)
3016         /* A "double" argument with excess precision being passed
3017            without a prototype or in variable arguments.  */
3018         parmval = convert (valtype, val);
3019       else if ((invalid_func_diag =
3020                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
3021         {
3022           error (invalid_func_diag);
3023           return -1;
3024         }
3025       else
3026         /* Convert `short' and `char' to full-size `int'.  */
3027         parmval = default_conversion (val);
3028
3029       VEC_replace (tree, values, parmnum, parmval);
3030       if (parmval == error_mark_node)
3031         error_args = true;
3032
3033       if (typetail)
3034         typetail = TREE_CHAIN (typetail);
3035     }
3036
3037   gcc_assert (parmnum == VEC_length (tree, values));
3038
3039   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
3040     {
3041       error ("too few arguments to function %qE", function);
3042       return -1;
3043     }
3044
3045   return error_args ? -1 : (int) parmnum;
3046 }
3047 \f
3048 /* This is the entry point used by the parser to build unary operators
3049    in the input.  CODE, a tree_code, specifies the unary operator, and
3050    ARG is the operand.  For unary plus, the C parser currently uses
3051    CONVERT_EXPR for code.
3052
3053    LOC is the location to use for the tree generated.
3054 */
3055
3056 struct c_expr
3057 parser_build_unary_op (location_t loc, enum tree_code code, struct c_expr arg)
3058 {
3059   struct c_expr result;
3060
3061   result.value = build_unary_op (loc, code, arg.value, 0);
3062   result.original_code = code;
3063   result.original_type = NULL;
3064
3065   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
3066     overflow_warning (loc, result.value);
3067
3068   return result;
3069 }
3070
3071 /* This is the entry point used by the parser to build binary operators
3072    in the input.  CODE, a tree_code, specifies the binary operator, and
3073    ARG1 and ARG2 are the operands.  In addition to constructing the
3074    expression, we check for operands that were written with other binary
3075    operators in a way that is likely to confuse the user.
3076
3077    LOCATION is the location of the binary operator.  */
3078
3079 struct c_expr
3080 parser_build_binary_op (location_t location, enum tree_code code,
3081                         struct c_expr arg1, struct c_expr arg2)
3082 {
3083   struct c_expr result;
3084
3085   enum tree_code code1 = arg1.original_code;
3086   enum tree_code code2 = arg2.original_code;
3087   tree type1 = (arg1.original_type
3088                 ? arg1.original_type
3089                 : TREE_TYPE (arg1.value));
3090   tree type2 = (arg2.original_type
3091                 ? arg2.original_type
3092                 : TREE_TYPE (arg2.value));
3093
3094   result.value = build_binary_op (location, code,
3095                                   arg1.value, arg2.value, 1);
3096   result.original_code = code;
3097   result.original_type = NULL;
3098
3099   if (TREE_CODE (result.value) == ERROR_MARK)
3100     return result;
3101
3102   if (location != UNKNOWN_LOCATION)
3103     protected_set_expr_location (result.value, location);
3104
3105   /* Check for cases such as x+y<<z which users are likely
3106      to misinterpret.  */
3107   if (warn_parentheses)
3108     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
3109
3110   if (warn_logical_op)
3111     warn_logical_operator (input_location, code, TREE_TYPE (result.value),
3112                            code1, arg1.value, code2, arg2.value);
3113
3114   /* Warn about comparisons against string literals, with the exception
3115      of testing for equality or inequality of a string literal with NULL.  */
3116   if (code == EQ_EXPR || code == NE_EXPR)
3117     {
3118       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
3119           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
3120         warning_at (location, OPT_Waddress,
3121                     "comparison with string literal results in unspecified behavior");
3122     }
3123   else if (TREE_CODE_CLASS (code) == tcc_comparison
3124            && (code1 == STRING_CST || code2 == STRING_CST))
3125     warning_at (location, OPT_Waddress,
3126                 "comparison with string literal results in unspecified behavior");
3127
3128   if (TREE_OVERFLOW_P (result.value)
3129       && !TREE_OVERFLOW_P (arg1.value)
3130       && !TREE_OVERFLOW_P (arg2.value))
3131     overflow_warning (location, result.value);
3132
3133   /* Warn about comparisons of different enum types.  */
3134   if (warn_enum_compare
3135       && TREE_CODE_CLASS (code) == tcc_comparison
3136       && TREE_CODE (type1) == ENUMERAL_TYPE
3137       && TREE_CODE (type2) == ENUMERAL_TYPE
3138       && TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
3139     warning_at (location, OPT_Wenum_compare,
3140                 "comparison between %qT and %qT",
3141                 type1, type2);
3142
3143   return result;
3144 }
3145 \f
3146 /* Return a tree for the difference of pointers OP0 and OP1.
3147    The resulting tree has type int.  */
3148
3149 static tree
3150 pointer_diff (location_t loc, tree op0, tree op1)
3151 {
3152   tree restype = ptrdiff_type_node;
3153   tree result, inttype;
3154
3155   addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op0)));
3156   addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op1)));
3157   tree target_type = TREE_TYPE (TREE_TYPE (op0));
3158   tree con0, con1, lit0, lit1;
3159   tree orig_op1 = op1;
3160
3161   /* If the operands point into different address spaces, we need to
3162      explicitly convert them to pointers into the common address space
3163      before we can subtract the numerical address values.  */
3164   if (as0 != as1)
3165     {
3166       addr_space_t as_common;
3167       tree common_type;
3168
3169       /* Determine the common superset address space.  This is guaranteed
3170          to exist because the caller verified that comp_target_types
3171          returned non-zero.  */
3172       if (!addr_space_superset (as0, as1, &as_common))
3173         gcc_unreachable ();
3174
3175       common_type = common_pointer_type (TREE_TYPE (op0), TREE_TYPE (op1));
3176       op0 = convert (common_type, op0);
3177       op1 = convert (common_type, op1);
3178     }
3179
3180   /* Determine integer type to perform computations in.  This will usually
3181      be the same as the result type (ptrdiff_t), but may need to be a wider
3182      type if pointers for the address space are wider than ptrdiff_t.  */
3183   if (TYPE_PRECISION (restype) < TYPE_PRECISION (TREE_TYPE (op0)))
3184     inttype = lang_hooks.types.type_for_size
3185                 (TYPE_PRECISION (TREE_TYPE (op0)), 0);
3186   else
3187     inttype = restype;
3188
3189
3190   if (TREE_CODE (target_type) == VOID_TYPE)
3191     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3192              "pointer of type %<void *%> used in subtraction");
3193   if (TREE_CODE (target_type) == FUNCTION_TYPE)
3194     pedwarn (loc, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3195              "pointer to a function used in subtraction");
3196
3197   /* If the conversion to ptrdiff_type does anything like widening or
3198      converting a partial to an integral mode, we get a convert_expression
3199      that is in the way to do any simplifications.
3200      (fold-const.c doesn't know that the extra bits won't be needed.
3201      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
3202      different mode in place.)
3203      So first try to find a common term here 'by hand'; we want to cover
3204      at least the cases that occur in legal static initializers.  */
3205   if (CONVERT_EXPR_P (op0)
3206       && (TYPE_PRECISION (TREE_TYPE (op0))
3207           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
3208     con0 = TREE_OPERAND (op0, 0);
3209   else
3210     con0 = op0;
3211   if (CONVERT_EXPR_P (op1)
3212       && (TYPE_PRECISION (TREE_TYPE (op1))
3213           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
3214     con1 = TREE_OPERAND (op1, 0);
3215   else
3216     con1 = op1;
3217
3218   if (TREE_CODE (con0) == PLUS_EXPR)
3219     {
3220       lit0 = TREE_OPERAND (con0, 1);
3221       con0 = TREE_OPERAND (con0, 0);
3222     }
3223   else
3224     lit0 = integer_zero_node;
3225
3226   if (TREE_CODE (con1) == PLUS_EXPR)
3227     {
3228       lit1 = TREE_OPERAND (con1, 1);
3229       con1 = TREE_OPERAND (con1, 0);
3230     }
3231   else
3232     lit1 = integer_zero_node;
3233
3234   if (operand_equal_p (con0, con1, 0))
3235     {
3236       op0 = lit0;
3237       op1 = lit1;
3238     }
3239
3240
3241   /* First do the subtraction as integers;
3242      then drop through to build the divide operator.
3243      Do not do default conversions on the minus operator
3244      in case restype is a short type.  */
3245
3246   op0 = build_binary_op (loc,
3247                          MINUS_EXPR, convert (inttype, op0),
3248                          convert (inttype, op1), 0);
3249   /* This generates an error if op1 is pointer to incomplete type.  */
3250   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
3251     error_at (loc, "arithmetic on pointer to an incomplete type");
3252
3253   /* This generates an error if op0 is pointer to incomplete type.  */
3254   op1 = c_size_in_bytes (target_type);
3255
3256   /* Divide by the size, in easiest possible way.  */
3257   result = fold_build2_loc (loc, EXACT_DIV_EXPR, inttype,
3258                             op0, convert (inttype, op1));
3259
3260   /* Convert to final result type if necessary.  */
3261   return convert (restype, result);
3262 }
3263 \f
3264 /* Construct and perhaps optimize a tree representation
3265    for a unary operation.  CODE, a tree_code, specifies the operation
3266    and XARG is the operand.
3267    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
3268    the default promotions (such as from short to int).
3269    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
3270    allows non-lvalues; this is only used to handle conversion of non-lvalue
3271    arrays to pointers in C99.
3272
3273    LOCATION is the location of the operator.  */
3274
3275 tree
3276 build_unary_op (location_t location,
3277                 enum tree_code code, tree xarg, int flag)
3278 {
3279   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3280   tree arg = xarg;
3281   tree argtype = 0;
3282   enum tree_code typecode;
3283   tree val;
3284   tree ret = error_mark_node;
3285   tree eptype = NULL_TREE;
3286   int noconvert = flag;
3287   const char *invalid_op_diag;
3288   bool int_operands;
3289
3290   int_operands = EXPR_INT_CONST_OPERANDS (xarg);
3291   if (int_operands)
3292     arg = remove_c_maybe_const_expr (arg);
3293
3294   if (code != ADDR_EXPR)
3295     arg = require_complete_type (arg);
3296
3297   typecode = TREE_CODE (TREE_TYPE (arg));
3298   if (typecode == ERROR_MARK)
3299     return error_mark_node;
3300   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
3301     typecode = INTEGER_TYPE;
3302
3303   if ((invalid_op_diag
3304        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
3305     {
3306       error_at (location, invalid_op_diag);
3307       return error_mark_node;
3308     }
3309
3310   if (TREE_CODE (arg) == EXCESS_PRECISION_EXPR)
3311     {
3312       eptype = TREE_TYPE (arg);
3313       arg = TREE_OPERAND (arg, 0);
3314     }
3315
3316   switch (code)
3317     {
3318     case CONVERT_EXPR:
3319       /* This is used for unary plus, because a CONVERT_EXPR
3320          is enough to prevent anybody from looking inside for
3321          associativity, but won't generate any code.  */
3322       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3323             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3324             || typecode == VECTOR_TYPE))
3325         {
3326           error_at (location, "wrong type argument to unary plus");
3327           return error_mark_node;
3328         }
3329       else if (!noconvert)
3330         arg = default_conversion (arg);
3331       arg = non_lvalue_loc (location, arg);
3332       break;
3333
3334     case NEGATE_EXPR:
3335       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3336             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
3337             || typecode == VECTOR_TYPE))
3338         {
3339           error_at (location, "wrong type argument to unary minus");
3340           return error_mark_node;
3341         }
3342       else if (!noconvert)
3343         arg = default_conversion (arg);
3344       break;
3345
3346     case BIT_NOT_EXPR:
3347       /* ~ works on integer types and non float vectors. */
3348       if (typecode == INTEGER_TYPE
3349           || (typecode == VECTOR_TYPE
3350               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
3351         {
3352           if (!noconvert)
3353             arg = default_conversion (arg);
3354         }
3355       else if (typecode == COMPLEX_TYPE)
3356         {
3357           code = CONJ_EXPR;
3358           pedwarn (location, OPT_pedantic,
3359                    "ISO C does not support %<~%> for complex conjugation");
3360           if (!noconvert)
3361             arg = default_conversion (arg);
3362         }
3363       else
3364         {
3365           error_at (location, "wrong type argument to bit-complement");
3366           return error_mark_node;
3367         }
3368       break;
3369
3370     case ABS_EXPR:
3371       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
3372         {
3373           error_at (location, "wrong type argument to abs");
3374           return error_mark_node;
3375         }
3376       else if (!noconvert)
3377         arg = default_conversion (arg);
3378       break;
3379
3380     case CONJ_EXPR:
3381       /* Conjugating a real value is a no-op, but allow it anyway.  */
3382       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3383             || typecode == COMPLEX_TYPE))
3384         {
3385           error_at (location, "wrong type argument to conjugation");
3386           return error_mark_node;
3387         }
3388       else if (!noconvert)
3389         arg = default_conversion (arg);
3390       break;
3391
3392     case TRUTH_NOT_EXPR:
3393       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3394           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3395           && typecode != COMPLEX_TYPE)
3396         {
3397           error_at (location,
3398                     "wrong type argument to unary exclamation mark");
3399           return error_mark_node;
3400         }
3401       arg = c_objc_common_truthvalue_conversion (location, arg);
3402       ret = invert_truthvalue_loc (location, arg);
3403       /* If the TRUTH_NOT_EXPR has been folded, reset the location.  */
3404       if (EXPR_P (ret) && EXPR_HAS_LOCATION (ret))
3405         location = EXPR_LOCATION (ret);
3406       goto return_build_unary_op;
3407
3408     case REALPART_EXPR:
3409       if (TREE_CODE (arg) == COMPLEX_CST)
3410         ret = TREE_REALPART (arg);
3411       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3412         ret = fold_build1_loc (location,
3413                                REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3414       else
3415         ret = arg;
3416       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3417         eptype = TREE_TYPE (eptype);
3418       goto return_build_unary_op;
3419
3420     case IMAGPART_EXPR:
3421       if (TREE_CODE (arg) == COMPLEX_CST)
3422         ret = TREE_IMAGPART (arg);
3423       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3424         ret = fold_build1_loc (location,
3425                                IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3426       else
3427         ret = omit_one_operand_loc (location, TREE_TYPE (arg),
3428                                 integer_zero_node, arg);
3429       if (eptype && TREE_CODE (eptype) == COMPLEX_TYPE)
3430         eptype = TREE_TYPE (eptype);
3431       goto return_build_unary_op;
3432
3433     case PREINCREMENT_EXPR:
3434     case POSTINCREMENT_EXPR:
3435     case PREDECREMENT_EXPR:
3436     case POSTDECREMENT_EXPR:
3437
3438       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3439         {
3440           tree inner = build_unary_op (location, code,
3441                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3442           if (inner == error_mark_node)
3443             return error_mark_node;
3444           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3445                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3446           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3447           C_MAYBE_CONST_EXPR_NON_CONST (ret) = 1;
3448           goto return_build_unary_op;
3449         }
3450
3451       /* Complain about anything that is not a true lvalue.  */
3452       if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3453                                   || code == POSTINCREMENT_EXPR)
3454                                  ? lv_increment
3455                                  : lv_decrement)))
3456         return error_mark_node;
3457
3458       if (warn_cxx_compat && TREE_CODE (TREE_TYPE (arg)) == ENUMERAL_TYPE)
3459         {
3460           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3461             warning_at (location, OPT_Wc___compat,
3462                         "increment of enumeration value is invalid in C++");
3463           else
3464             warning_at (location, OPT_Wc___compat,
3465                         "decrement of enumeration value is invalid in C++");
3466         }
3467
3468       /* Ensure the argument is fully folded inside any SAVE_EXPR.  */
3469       arg = c_fully_fold (arg, false, NULL);
3470
3471       /* Increment or decrement the real part of the value,
3472          and don't change the imaginary part.  */
3473       if (typecode == COMPLEX_TYPE)
3474         {
3475           tree real, imag;
3476
3477           pedwarn (location, OPT_pedantic,
3478                    "ISO C does not support %<++%> and %<--%> on complex types");
3479
3480           arg = stabilize_reference (arg);
3481           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3482           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3483           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3484           if (real == error_mark_node || imag == error_mark_node)
3485             return error_mark_node;
3486           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3487                         real, imag);
3488           goto return_build_unary_op;
3489         }
3490
3491       /* Report invalid types.  */
3492
3493       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3494           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3495         {
3496           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3497             error_at (location, "wrong type argument to increment");
3498           else
3499             error_at (location, "wrong type argument to decrement");
3500
3501           return error_mark_node;
3502         }
3503
3504       {
3505         tree inc;
3506
3507         argtype = TREE_TYPE (arg);
3508
3509         /* Compute the increment.  */
3510
3511         if (typecode == POINTER_TYPE)
3512           {
3513             /* If pointer target is an undefined struct,
3514                we just cannot know how to do the arithmetic.  */
3515             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3516               {
3517                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3518                   error_at (location,
3519                             "increment of pointer to unknown structure");
3520                 else
3521                   error_at (location,
3522                             "decrement of pointer to unknown structure");
3523               }
3524             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3525                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3526               {
3527                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3528                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3529                            "wrong type argument to increment");
3530                 else
3531                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3532                            "wrong type argument to decrement");
3533               }
3534
3535             inc = c_size_in_bytes (TREE_TYPE (argtype));
3536             inc = fold_convert_loc (location, sizetype, inc);
3537           }
3538         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3539           {
3540             /* For signed fract types, we invert ++ to -- or
3541                -- to ++, and change inc from 1 to -1, because
3542                it is not possible to represent 1 in signed fract constants.
3543                For unsigned fract types, the result always overflows and
3544                we get an undefined (original) or the maximum value.  */
3545             if (code == PREINCREMENT_EXPR)
3546               code = PREDECREMENT_EXPR;
3547             else if (code == PREDECREMENT_EXPR)
3548               code = PREINCREMENT_EXPR;
3549             else if (code == POSTINCREMENT_EXPR)
3550               code = POSTDECREMENT_EXPR;
3551             else /* code == POSTDECREMENT_EXPR  */
3552               code = POSTINCREMENT_EXPR;
3553
3554             inc = integer_minus_one_node;
3555             inc = convert (argtype, inc);
3556           }
3557         else
3558           {
3559             inc = integer_one_node;
3560             inc = convert (argtype, inc);
3561           }
3562
3563         /* Report a read-only lvalue.  */
3564         if (TYPE_READONLY (argtype))
3565           {
3566             readonly_error (arg,
3567                             ((code == PREINCREMENT_EXPR
3568                               || code == POSTINCREMENT_EXPR)
3569                              ? lv_increment : lv_decrement));
3570             return error_mark_node;
3571           }
3572         else if (TREE_READONLY (arg))
3573           readonly_warning (arg,
3574                             ((code == PREINCREMENT_EXPR
3575                               || code == POSTINCREMENT_EXPR)
3576                              ? lv_increment : lv_decrement));
3577
3578         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3579           val = boolean_increment (code, arg);
3580         else
3581           val = build2 (code, TREE_TYPE (arg), arg, inc);
3582         TREE_SIDE_EFFECTS (val) = 1;
3583         if (TREE_CODE (val) != code)
3584           TREE_NO_WARNING (val) = 1;
3585         ret = val;
3586         goto return_build_unary_op;
3587       }
3588
3589     case ADDR_EXPR:
3590       /* Note that this operation never does default_conversion.  */
3591
3592       /* The operand of unary '&' must be an lvalue (which excludes
3593          expressions of type void), or, in C99, the result of a [] or
3594          unary '*' operator.  */
3595       if (VOID_TYPE_P (TREE_TYPE (arg))
3596           && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
3597           && (TREE_CODE (arg) != INDIRECT_REF
3598               || !flag_isoc99))
3599         pedwarn (location, 0, "taking address of expression of type %<void%>");
3600
3601       /* Let &* cancel out to simplify resulting code.  */
3602       if (TREE_CODE (arg) == INDIRECT_REF)
3603         {
3604           /* Don't let this be an lvalue.  */
3605           if (lvalue_p (TREE_OPERAND (arg, 0)))
3606             return non_lvalue_loc (location, TREE_OPERAND (arg, 0));
3607           ret = TREE_OPERAND (arg, 0);
3608           goto return_build_unary_op;
3609         }
3610
3611       /* For &x[y], return x+y */
3612       if (TREE_CODE (arg) == ARRAY_REF)
3613         {
3614           tree op0 = TREE_OPERAND (arg, 0);
3615           if (!c_mark_addressable (op0))
3616             return error_mark_node;
3617           return build_binary_op (location, PLUS_EXPR,
3618                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3619                                    ? array_to_pointer_conversion (location,
3620                                                                   op0)
3621                                    : op0),
3622                                   TREE_OPERAND (arg, 1), 1);
3623         }
3624
3625       /* Anything not already handled and not a true memory reference
3626          or a non-lvalue array is an error.  */
3627       else if (typecode != FUNCTION_TYPE && !flag
3628                && !lvalue_or_else (arg, lv_addressof))
3629         return error_mark_node;
3630
3631       /* Move address operations inside C_MAYBE_CONST_EXPR to simplify
3632          folding later.  */
3633       if (TREE_CODE (arg) == C_MAYBE_CONST_EXPR)
3634         {
3635           tree inner = build_unary_op (location, code,
3636                                        C_MAYBE_CONST_EXPR_EXPR (arg), flag);
3637           ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
3638                         C_MAYBE_CONST_EXPR_PRE (arg), inner);
3639           gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (arg));
3640           C_MAYBE_CONST_EXPR_NON_CONST (ret)
3641             = C_MAYBE_CONST_EXPR_NON_CONST (arg);
3642           goto return_build_unary_op;
3643         }
3644
3645       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3646       argtype = TREE_TYPE (arg);
3647
3648       /* If the lvalue is const or volatile, merge that into the type
3649          to which the address will point.  Note that you can't get a
3650          restricted pointer by taking the address of something, so we
3651          only have to deal with `const' and `volatile' here.  */
3652       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3653           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3654           argtype = c_build_type_variant (argtype,
3655                                           TREE_READONLY (arg),
3656                                           TREE_THIS_VOLATILE (arg));
3657
3658       if (!c_mark_addressable (arg))
3659         return error_mark_node;
3660
3661       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3662                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3663
3664       argtype = build_pointer_type (argtype);
3665
3666       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3667          when we have proper support for integer constant expressions.  */
3668       val = get_base_address (arg);
3669       if (val && TREE_CODE (val) == INDIRECT_REF
3670           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3671         {
3672           tree op0 = fold_convert_loc (location, sizetype,
3673                                        fold_offsetof (arg, val)), op1;
3674
3675           op1 = fold_convert_loc (location, argtype, TREE_OPERAND (val, 0));
3676           ret = fold_build2_loc (location, POINTER_PLUS_EXPR, argtype, op1, op0);
3677           goto return_build_unary_op;
3678         }
3679
3680       val = build1 (ADDR_EXPR, argtype, arg);
3681
3682       ret = val;
3683       goto return_build_unary_op;
3684
3685     default:
3686       gcc_unreachable ();
3687     }
3688
3689   if (argtype == 0)
3690     argtype = TREE_TYPE (arg);
3691   if (TREE_CODE (arg) == INTEGER_CST)
3692     ret = (require_constant_value
3693            ? fold_build1_initializer_loc (location, code, argtype, arg)
3694            : fold_build1_loc (location, code, argtype, arg));
3695   else
3696     ret = build1 (code, argtype, arg);
3697  return_build_unary_op:
3698   gcc_assert (ret != error_mark_node);
3699   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret)
3700       && !(TREE_CODE (xarg) == INTEGER_CST && !TREE_OVERFLOW (xarg)))
3701     ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
3702   else if (TREE_CODE (ret) != INTEGER_CST && int_operands)
3703     ret = note_integer_operands (ret);
3704   if (eptype)
3705     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
3706   protected_set_expr_location (ret, location);
3707   return ret;
3708 }
3709
3710 /* Return nonzero if REF is an lvalue valid for this language.
3711    Lvalues can be assigned, unless their type has TYPE_READONLY.
3712    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3713
3714 bool
3715 lvalue_p (const_tree ref)
3716 {
3717   const enum tree_code code = TREE_CODE (ref);
3718
3719   switch (code)
3720     {
3721     case REALPART_EXPR:
3722     case IMAGPART_EXPR:
3723     case COMPONENT_REF:
3724       return lvalue_p (TREE_OPERAND (ref, 0));
3725
3726     case C_MAYBE_CONST_EXPR:
3727       return lvalue_p (TREE_OPERAND (ref, 1));
3728
3729     case COMPOUND_LITERAL_EXPR:
3730     case STRING_CST:
3731       return 1;
3732
3733     case INDIRECT_REF:
3734     case ARRAY_REF:
3735     case VAR_DECL:
3736     case PARM_DECL:
3737     case RESULT_DECL:
3738     case ERROR_MARK:
3739       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3740               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3741
3742     case BIND_EXPR:
3743       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3744
3745     default:
3746       return 0;
3747     }
3748 }
3749 \f
3750 /* Give an error for storing in something that is 'const'.  */
3751
3752 static void
3753 readonly_error (tree arg, enum lvalue_use use)
3754 {
3755   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3756               || use == lv_asm);
3757   /* Using this macro rather than (for example) arrays of messages
3758      ensures that all the format strings are checked at compile
3759      time.  */
3760 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3761                                    : (use == lv_increment ? (I)         \
3762                                    : (use == lv_decrement ? (D) : (AS))))
3763   if (TREE_CODE (arg) == COMPONENT_REF)
3764     {
3765       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3766         readonly_error (TREE_OPERAND (arg, 0), use);
3767       else
3768         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3769                              G_("increment of read-only member %qD"),
3770                              G_("decrement of read-only member %qD"),
3771                              G_("read-only member %qD used as %<asm%> output")),
3772                TREE_OPERAND (arg, 1));
3773     }
3774   else if (TREE_CODE (arg) == VAR_DECL)
3775     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3776                          G_("increment of read-only variable %qD"),
3777                          G_("decrement of read-only variable %qD"),
3778                          G_("read-only variable %qD used as %<asm%> output")),
3779            arg);
3780   else
3781     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3782                          G_("increment of read-only location %qE"),
3783                          G_("decrement of read-only location %qE"),
3784                          G_("read-only location %qE used as %<asm%> output")),
3785            arg);
3786 }
3787
3788 /* Give a warning for storing in something that is read-only in GCC
3789    terms but not const in ISO C terms.  */
3790
3791 static void
3792 readonly_warning (tree arg, enum lvalue_use use)
3793 {
3794   switch (use)
3795     {
3796     case lv_assign:
3797       warning (0, "assignment of read-only location %qE", arg);
3798       break;
3799     case lv_increment:
3800       warning (0, "increment of read-only location %qE", arg);
3801       break;
3802     case lv_decrement:
3803       warning (0, "decrement of read-only location %qE", arg);
3804       break;
3805     default:
3806       gcc_unreachable ();
3807     }
3808   return;
3809 }
3810
3811
3812 /* Return nonzero if REF is an lvalue valid for this language;
3813    otherwise, print an error message and return zero.  USE says
3814    how the lvalue is being used and so selects the error message.  */
3815
3816 static int
3817 lvalue_or_else (const_tree ref, enum lvalue_use use)
3818 {
3819   int win = lvalue_p (ref);
3820
3821   if (!win)
3822     lvalue_error (use);
3823
3824   return win;
3825 }
3826 \f
3827 /* Mark EXP saying that we need to be able to take the
3828    address of it; it should not be allocated in a register.
3829    Returns true if successful.  */
3830
3831 bool
3832 c_mark_addressable (tree exp)
3833 {
3834   tree x = exp;
3835
3836   while (1)
3837     switch (TREE_CODE (x))
3838       {
3839       case COMPONENT_REF:
3840         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3841           {
3842             error
3843               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3844             return false;
3845           }
3846
3847         /* ... fall through ...  */
3848
3849       case ADDR_EXPR:
3850       case ARRAY_REF:
3851       case REALPART_EXPR:
3852       case IMAGPART_EXPR:
3853         x = TREE_OPERAND (x, 0);
3854         break;
3855
3856       case COMPOUND_LITERAL_EXPR:
3857       case CONSTRUCTOR:
3858         TREE_ADDRESSABLE (x) = 1;
3859         return true;
3860
3861       case VAR_DECL:
3862       case CONST_DECL:
3863       case PARM_DECL:
3864       case RESULT_DECL:
3865         if (C_DECL_REGISTER (x)
3866             && DECL_NONLOCAL (x))
3867           {
3868             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3869               {
3870                 error
3871                   ("global register variable %qD used in nested function", x);
3872                 return false;
3873               }
3874             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3875           }
3876         else if (C_DECL_REGISTER (x))
3877           {
3878             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3879               error ("address of global register variable %qD requested", x);
3880             else
3881               error ("address of register variable %qD requested", x);
3882             return false;
3883           }
3884
3885         /* drops in */
3886       case FUNCTION_DECL:
3887         TREE_ADDRESSABLE (x) = 1;
3888         /* drops out */
3889       default:
3890         return true;
3891     }
3892 }
3893 \f
3894 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  If
3895    IFEXP_BCP then the condition is a call to __builtin_constant_p, and
3896    if folded to an integer constant then the unselected half may
3897    contain arbitrary operations not normally permitted in constant
3898    expressions.  Set the location of the expression to LOC.  */
3899
3900 tree
3901 build_conditional_expr (location_t colon_loc, tree ifexp, bool ifexp_bcp,
3902                         tree op1, tree op1_original_type, tree op2,
3903                         tree op2_original_type)
3904 {
3905   tree type1;
3906   tree type2;
3907   enum tree_code code1;
3908   enum tree_code code2;
3909   tree result_type = NULL;
3910   tree ep_result_type = NULL;
3911   tree orig_op1 = op1, orig_op2 = op2;
3912   bool int_const, op1_int_operands, op2_int_operands, int_operands;
3913   bool ifexp_int_operands;
3914   tree ret;
3915   bool objc_ok;
3916
3917   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
3918   if (op1_int_operands)
3919     op1 = remove_c_maybe_const_expr (op1);
3920   op2_int_operands = EXPR_INT_CONST_OPERANDS (orig_op2);
3921   if (op2_int_operands)
3922     op2 = remove_c_maybe_const_expr (op2);
3923   ifexp_int_operands = EXPR_INT_CONST_OPERANDS (ifexp);
3924   if (ifexp_int_operands)
3925     ifexp = remove_c_maybe_const_expr (ifexp);
3926
3927   /* Promote both alternatives.  */
3928
3929   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3930     op1 = default_conversion (op1);
3931   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3932     op2 = default_conversion (op2);
3933
3934   if (TREE_CODE (ifexp) == ERROR_MARK
3935       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3936       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3937     return error_mark_node;
3938
3939   type1 = TREE_TYPE (op1);
3940   code1 = TREE_CODE (type1);
3941   type2 = TREE_TYPE (op2);
3942   code2 = TREE_CODE (type2);
3943
3944   /* C90 does not permit non-lvalue arrays in conditional expressions.
3945      In C99 they will be pointers by now.  */
3946   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3947     {
3948       error_at (colon_loc, "non-lvalue array in conditional expression");
3949       return error_mark_node;
3950     }
3951
3952   objc_ok = objc_compare_types (type1, type2, -3, NULL_TREE);
3953
3954   if ((TREE_CODE (op1) == EXCESS_PRECISION_EXPR
3955        || TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3956       && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3957           || code1 == COMPLEX_TYPE)
3958       && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3959           || code2 == COMPLEX_TYPE))
3960     {
3961       ep_result_type = c_common_type (type1, type2);
3962       if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
3963         {
3964           op1 = TREE_OPERAND (op1, 0);
3965           type1 = TREE_TYPE (op1);
3966           gcc_assert (TREE_CODE (type1) == code1);
3967         }
3968       if (TREE_CODE (op2) == EXCESS_PRECISION_EXPR)
3969         {
3970           op2 = TREE_OPERAND (op2, 0);
3971           type2 = TREE_TYPE (op2);
3972           gcc_assert (TREE_CODE (type2) == code2);
3973         }
3974     }
3975
3976   if (warn_cxx_compat)
3977     {
3978       tree t1 = op1_original_type ? op1_original_type : TREE_TYPE (orig_op1);
3979       tree t2 = op2_original_type ? op2_original_type : TREE_TYPE (orig_op2);
3980
3981       if (TREE_CODE (t1) == ENUMERAL_TYPE
3982           && TREE_CODE (t2) == ENUMERAL_TYPE
3983           && TYPE_MAIN_VARIANT (t1) != TYPE_MAIN_VARIANT (t2))
3984         warning_at (colon_loc, OPT_Wc___compat,
3985                     ("different enum types in conditional is "
3986                      "invalid in C++: %qT vs %qT"),
3987                     t1, t2);
3988     }
3989
3990   /* Quickly detect the usual case where op1 and op2 have the same type
3991      after promotion.  */
3992   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3993     {
3994       if (type1 == type2)
3995         result_type = type1;
3996       else
3997         result_type = TYPE_MAIN_VARIANT (type1);
3998     }
3999   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
4000             || code1 == COMPLEX_TYPE)
4001            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
4002                || code2 == COMPLEX_TYPE))
4003     {
4004       result_type = c_common_type (type1, type2);
4005
4006       /* If -Wsign-compare, warn here if type1 and type2 have
4007          different signedness.  We'll promote the signed to unsigned
4008          and later code won't know it used to be different.
4009          Do this check on the original types, so that explicit casts
4010          will be considered, but default promotions won't.  */
4011       if (c_inhibit_evaluation_warnings == 0)
4012         {
4013           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
4014           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
4015
4016           if (unsigned_op1 ^ unsigned_op2)
4017             {
4018               bool ovf;
4019
4020               /* Do not warn if the result type is signed, since the
4021                  signed type will only be chosen if it can represent
4022                  all the values of the unsigned type.  */
4023               if (!TYPE_UNSIGNED (result_type))
4024                 /* OK */;
4025               else
4026                 {
4027                   bool op1_maybe_const = true;
4028                   bool op2_maybe_const = true;
4029
4030                   /* Do not warn if the signed quantity is an
4031                      unsuffixed integer literal (or some static
4032                      constant expression involving such literals) and
4033                      it is non-negative.  This warning requires the
4034                      operands to be folded for best results, so do
4035                      that folding in this case even without
4036                      warn_sign_compare to avoid warning options
4037                      possibly affecting code generation.  */
4038                   c_inhibit_evaluation_warnings
4039                     += (ifexp == truthvalue_false_node);
4040                   op1 = c_fully_fold (op1, require_constant_value,
4041                                       &op1_maybe_const);
4042                   c_inhibit_evaluation_warnings
4043                     -= (ifexp == truthvalue_false_node);
4044
4045                   c_inhibit_evaluation_warnings
4046                     += (ifexp == truthvalue_true_node);
4047                   op2 = c_fully_fold (op2, require_constant_value,
4048                                       &op2_maybe_const);
4049                   c_inhibit_evaluation_warnings
4050                     -= (ifexp == truthvalue_true_node);
4051
4052                   if (warn_sign_compare)
4053                     {
4054                       if ((unsigned_op2
4055                            && tree_expr_nonnegative_warnv_p (op1, &ovf))
4056                           || (unsigned_op1
4057                               && tree_expr_nonnegative_warnv_p (op2, &ovf)))
4058                         /* OK */;
4059                       else
4060                         warning_at (colon_loc, OPT_Wsign_compare,
4061                                     ("signed and unsigned type in "
4062                                      "conditional expression"));
4063                     }
4064                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
4065                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
4066                   if (!op2_maybe_const || TREE_CODE (op2) != INTEGER_CST)
4067                     op2 = c_wrap_maybe_const (op2, !op2_maybe_const);
4068                 }
4069             }
4070         }
4071     }
4072   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
4073     {
4074       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
4075         pedwarn (colon_loc, OPT_pedantic,
4076                  "ISO C forbids conditional expr with only one void side");
4077       result_type = void_type_node;
4078     }
4079   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
4080     {
4081       addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
4082       addr_space_t as2 = TYPE_ADDR_SPACE (TREE_TYPE (type2));
4083       addr_space_t as_common;
4084
4085       if (comp_target_types (colon_loc, type1, type2))
4086         result_type = common_pointer_type (type1, type2);
4087       else if (null_pointer_constant_p (orig_op1))
4088         result_type = type2;
4089       else if (null_pointer_constant_p (orig_op2))
4090         result_type = type1;
4091       else if (!addr_space_superset (as1, as2, &as_common))
4092         {
4093           error_at (colon_loc, "pointers to disjoint address spaces "
4094                     "used in conditional expression");
4095           return error_mark_node;
4096         }
4097       else if (VOID_TYPE_P (TREE_TYPE (type1)))
4098         {
4099           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
4100             pedwarn (colon_loc, OPT_pedantic,
4101                      "ISO C forbids conditional expr between "
4102                      "%<void *%> and function pointer");
4103           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
4104                                                           TREE_TYPE (type2)));
4105         }
4106       else if (VOID_TYPE_P (TREE_TYPE (type2)))
4107         {
4108           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
4109             pedwarn (colon_loc, OPT_pedantic,
4110                      "ISO C forbids conditional expr between "
4111                      "%<void *%> and function pointer");
4112           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
4113                                                           TREE_TYPE (type1)));
4114         }
4115       else
4116         {
4117           int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
4118
4119           if (!objc_ok)
4120             pedwarn (colon_loc, 0,
4121                      "pointer type mismatch in conditional expression");
4122           result_type = build_pointer_type
4123                           (build_qualified_type (void_type_node, qual));
4124         }
4125     }
4126   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
4127     {
4128       if (!null_pointer_constant_p (orig_op2))
4129         pedwarn (colon_loc, 0,
4130                  "pointer/integer type mismatch in conditional expression");
4131       else
4132         {
4133           op2 = null_pointer_node;
4134         }
4135       result_type = type1;
4136     }
4137   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
4138     {
4139       if (!null_pointer_constant_p (orig_op1))
4140         pedwarn (colon_loc, 0,
4141                  "pointer/integer type mismatch in conditional expression");
4142       else
4143         {
4144           op1 = null_pointer_node;
4145         }
4146       result_type = type2;
4147     }
4148
4149   if (!result_type)
4150     {
4151       if (flag_cond_mismatch)
4152         result_type = void_type_node;
4153       else
4154         {
4155           error_at (colon_loc, "type mismatch in conditional expression");
4156           return error_mark_node;
4157         }
4158     }
4159
4160   /* Merge const and volatile flags of the incoming types.  */
4161   result_type
4162     = build_type_variant (result_type,
4163                           TYPE_READONLY (type1) || TYPE_READONLY (type2),
4164                           TYPE_VOLATILE (type1) || TYPE_VOLATILE (type2));
4165
4166   if (result_type != type1)
4167     op1 = convert_and_check (result_type, op1);
4168   if (result_type != type2)
4169     op2 = convert_and_check (result_type, op2);
4170
4171   if (ifexp_bcp && ifexp == truthvalue_true_node)
4172     {
4173       op2_int_operands = true;
4174       op1 = c_fully_fold (op1, require_constant_value, NULL);
4175     }
4176   if (ifexp_bcp && ifexp == truthvalue_false_node)
4177     {
4178       op1_int_operands = true;
4179       op2 = c_fully_fold (op2, require_constant_value, NULL);
4180     }
4181   int_const = int_operands = (ifexp_int_operands
4182                               && op1_int_operands
4183                               && op2_int_operands);
4184   if (int_operands)
4185     {
4186       int_const = ((ifexp == truthvalue_true_node
4187                     && TREE_CODE (orig_op1) == INTEGER_CST
4188                     && !TREE_OVERFLOW (orig_op1))
4189                    || (ifexp == truthvalue_false_node
4190                        && TREE_CODE (orig_op2) == INTEGER_CST
4191                        && !TREE_OVERFLOW (orig_op2)));
4192     }
4193   if (int_const || (ifexp_bcp && TREE_CODE (ifexp) == INTEGER_CST))
4194     ret = fold_build3_loc (colon_loc, COND_EXPR, result_type, ifexp, op1, op2);
4195   else
4196     {
4197       ret = build3 (COND_EXPR, result_type, ifexp, op1, op2);
4198       if (int_operands)
4199         ret = note_integer_operands (ret);
4200     }
4201   if (ep_result_type)
4202     ret = build1 (EXCESS_PRECISION_EXPR, ep_result_type, ret);
4203
4204   protected_set_expr_location (ret, colon_loc);
4205   return ret;
4206 }
4207 \f
4208 /* Return a compound expression that performs two expressions and
4209    returns the value of the second of them.
4210
4211    LOC is the location of the COMPOUND_EXPR.  */
4212
4213 tree
4214 build_compound_expr (location_t loc, tree expr1, tree expr2)
4215 {
4216   bool expr1_int_operands, expr2_int_operands;
4217   tree eptype = NULL_TREE;
4218   tree ret;
4219
4220   expr1_int_operands = EXPR_INT_CONST_OPERANDS (expr1);
4221   if (expr1_int_operands)
4222     expr1 = remove_c_maybe_const_expr (expr1);
4223   expr2_int_operands = EXPR_INT_CONST_OPERANDS (expr2);
4224   if (expr2_int_operands)
4225     expr2 = remove_c_maybe_const_expr (expr2);
4226
4227   if (TREE_CODE (expr1) == EXCESS_PRECISION_EXPR)
4228     expr1 = TREE_OPERAND (expr1, 0);
4229   if (TREE_CODE (expr2) == EXCESS_PRECISION_EXPR)
4230     {
4231       eptype = TREE_TYPE (expr2);
4232       expr2 = TREE_OPERAND (expr2, 0);
4233     }
4234
4235   if (!TREE_SIDE_EFFECTS (expr1))
4236     {
4237       /* The left-hand operand of a comma expression is like an expression
4238          statement: with -Wunused, we should warn if it doesn't have
4239          any side-effects, unless it was explicitly cast to (void).  */
4240       if (warn_unused_value)
4241         {
4242           if (VOID_TYPE_P (TREE_TYPE (expr1))
4243               && CONVERT_EXPR_P (expr1))
4244             ; /* (void) a, b */
4245           else if (VOID_TYPE_P (TREE_TYPE (expr1))
4246                    && TREE_CODE (expr1) == COMPOUND_EXPR
4247                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
4248             ; /* (void) a, (void) b, c */
4249           else
4250             warning_at (loc, OPT_Wunused_value,
4251                         "left-hand operand of comma expression has no effect");
4252         }
4253     }
4254
4255   /* With -Wunused, we should also warn if the left-hand operand does have
4256      side-effects, but computes a value which is not used.  For example, in
4257      `foo() + bar(), baz()' the result of the `+' operator is not used,
4258      so we should issue a warning.  */
4259   else if (warn_unused_value)
4260     warn_if_unused_value (expr1, loc);
4261
4262   if (expr2 == error_mark_node)
4263     return error_mark_node;
4264
4265   ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
4266
4267   if (flag_isoc99
4268       && expr1_int_operands
4269       && expr2_int_operands)
4270     ret = note_integer_operands (ret);
4271
4272   if (eptype)
4273     ret = build1 (EXCESS_PRECISION_EXPR, eptype, ret);
4274
4275   protected_set_expr_location (ret, loc);
4276   return ret;
4277 }
4278
4279 /* Issue -Wcast-qual warnings when appropriate.  TYPE is the type to
4280    which we are casting.  OTYPE is the type of the expression being
4281    cast.  Both TYPE and OTYPE are pointer types.  -Wcast-qual appeared
4282    on the command line.  Named address space qualifiers are not handled
4283    here, because they result in different warnings.  */
4284
4285 static void
4286 handle_warn_cast_qual (tree type, tree otype)
4287 {
4288   tree in_type = type;
4289   tree in_otype = otype;
4290   int added = 0;
4291   int discarded = 0;
4292   bool is_const;
4293
4294   /* Check that the qualifiers on IN_TYPE are a superset of the
4295      qualifiers of IN_OTYPE.  The outermost level of POINTER_TYPE
4296      nodes is uninteresting and we stop as soon as we hit a
4297      non-POINTER_TYPE node on either type.  */
4298   do
4299     {
4300       in_otype = TREE_TYPE (in_otype);
4301       in_type = TREE_TYPE (in_type);
4302
4303       /* GNU C allows cv-qualified function types.  'const' means the
4304          function is very pure, 'volatile' means it can't return.  We
4305          need to warn when such qualifiers are added, not when they're
4306          taken away.  */
4307       if (TREE_CODE (in_otype) == FUNCTION_TYPE
4308           && TREE_CODE (in_type) == FUNCTION_TYPE)
4309         added |= (TYPE_QUALS_NO_ADDR_SPACE (in_type)
4310                   & ~TYPE_QUALS_NO_ADDR_SPACE (in_otype));
4311       else
4312         discarded |= (TYPE_QUALS_NO_ADDR_SPACE (in_otype)
4313                       & ~TYPE_QUALS_NO_ADDR_SPACE (in_type));
4314     }
4315   while (TREE_CODE (in_type) == POINTER_TYPE
4316          && TREE_CODE (in_otype) == POINTER_TYPE);
4317
4318   if (added)
4319     warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
4320
4321   if (discarded)
4322     /* There are qualifiers present in IN_OTYPE that are not present
4323        in IN_TYPE.  */
4324     warning (OPT_Wcast_qual,
4325              "cast discards qualifiers from pointer target type");
4326
4327   if (added || discarded)
4328     return;
4329
4330   /* A cast from **T to const **T is unsafe, because it can cause a
4331      const value to be changed with no additional warning.  We only
4332      issue this warning if T is the same on both sides, and we only
4333      issue the warning if there are the same number of pointers on
4334      both sides, as otherwise the cast is clearly unsafe anyhow.  A
4335      cast is unsafe when a qualifier is added at one level and const
4336      is not present at all outer levels.
4337
4338      To issue this warning, we check at each level whether the cast
4339      adds new qualifiers not already seen.  We don't need to special
4340      case function types, as they won't have the same
4341      TYPE_MAIN_VARIANT.  */
4342
4343   if (TYPE_MAIN_VARIANT (in_type) != TYPE_MAIN_VARIANT (in_otype))
4344     return;
4345   if (TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE)
4346     return;
4347
4348   in_type = type;
4349   in_otype = otype;
4350   is_const = TYPE_READONLY (TREE_TYPE (in_type));
4351   do
4352     {
4353       in_type = TREE_TYPE (in_type);
4354       in_otype = TREE_TYPE (in_otype);
4355       if ((TYPE_QUALS (in_type) &~ TYPE_QUALS (in_otype)) != 0
4356           && !is_const)
4357         {
4358           warning (OPT_Wcast_qual,
4359                    ("new qualifiers in middle of multi-level non-const cast "
4360                     "are unsafe"));
4361           break;
4362         }
4363       if (is_const)
4364         is_const = TYPE_READONLY (in_type);
4365     }
4366   while (TREE_CODE (in_type) == POINTER_TYPE);
4367 }
4368
4369 /* Build an expression representing a cast to type TYPE of expression EXPR.
4370    LOC is the location of the cast-- typically the open paren of the cast.  */
4371
4372 tree
4373 build_c_cast (location_t loc, tree type, tree expr)
4374 {
4375   tree value;
4376
4377   if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
4378     expr = TREE_OPERAND (expr, 0);
4379
4380   value = expr;
4381
4382   if (type == error_mark_node || expr == error_mark_node)
4383     return error_mark_node;
4384
4385   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
4386      only in <protocol> qualifications.  But when constructing cast expressions,
4387      the protocols do matter and must be kept around.  */
4388   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
4389     return build1 (NOP_EXPR, type, expr);
4390
4391   type = TYPE_MAIN_VARIANT (type);
4392
4393   if (TREE_CODE (type) == ARRAY_TYPE)
4394     {
4395       error_at (loc, "cast specifies array type");
4396       return error_mark_node;
4397     }
4398
4399   if (TREE_CODE (type) == FUNCTION_TYPE)
4400     {
4401       error_at (loc, "cast specifies function type");
4402       return error_mark_node;
4403     }
4404
4405   if (!VOID_TYPE_P (type))
4406     {
4407       value = require_complete_type (value);
4408       if (value == error_mark_node)
4409         return error_mark_node;
4410     }
4411
4412   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
4413     {
4414       if (TREE_CODE (type) == RECORD_TYPE
4415           || TREE_CODE (type) == UNION_TYPE)
4416         pedwarn (loc, OPT_pedantic,
4417                  "ISO C forbids casting nonscalar to the same type");
4418     }
4419   else if (TREE_CODE (type) == UNION_TYPE)
4420     {
4421       tree field;
4422
4423       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4424         if (TREE_TYPE (field) != error_mark_node
4425             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
4426                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
4427           break;
4428
4429       if (field)
4430         {
4431           tree t;
4432           bool maybe_const = true;
4433
4434           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4435           t = c_fully_fold (value, false, &maybe_const);
4436           t = build_constructor_single (type, field, t);
4437           if (!maybe_const)
4438             t = c_wrap_maybe_const (t, true);
4439           t = digest_init (loc, type, t,
4440                            NULL_TREE, false, true, 0);
4441           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4442           return t;
4443         }
4444       error_at (loc, "cast to union type from type not present in union");
4445       return error_mark_node;
4446     }
4447   else
4448     {
4449       tree otype, ovalue;
4450
4451       if (type == void_type_node)
4452         {
4453           tree t = build1 (CONVERT_EXPR, type, value);
4454           SET_EXPR_LOCATION (t, loc);
4455           return t;
4456         }
4457
4458       otype = TREE_TYPE (value);
4459
4460       /* Optionally warn about potentially worrisome casts.  */
4461       if (warn_cast_qual
4462           && TREE_CODE (type) == POINTER_TYPE
4463           && TREE_CODE (otype) == POINTER_TYPE)
4464         handle_warn_cast_qual (type, otype);
4465
4466       /* Warn about conversions between pointers to disjoint
4467          address spaces.  */
4468       if (TREE_CODE (type) == POINTER_TYPE
4469           && TREE_CODE (otype) == POINTER_TYPE
4470           && !null_pointer_constant_p (value))
4471         {
4472           addr_space_t as_to = TYPE_ADDR_SPACE (TREE_TYPE (type));
4473           addr_space_t as_from = TYPE_ADDR_SPACE (TREE_TYPE (otype));
4474           addr_space_t as_common;
4475
4476           if (!addr_space_superset (as_to, as_from, &as_common))
4477             {
4478               if (ADDR_SPACE_GENERIC_P (as_from))
4479                 warning_at (loc, 0, "cast to %s address space pointer "
4480                             "from disjoint generic address space pointer",
4481                             c_addr_space_name (as_to));
4482
4483               else if (ADDR_SPACE_GENERIC_P (as_to))
4484                 warning_at (loc, 0, "cast to generic address space pointer "
4485                             "from disjoint %s address space pointer",
4486                             c_addr_space_name (as_from));
4487
4488               else
4489                 warning_at (loc, 0, "cast to %s address space pointer "
4490                             "from disjoint %s address space pointer",
4491                             c_addr_space_name (as_to),
4492                             c_addr_space_name (as_from));
4493             }
4494         }
4495
4496       /* Warn about possible alignment problems.  */
4497       if (STRICT_ALIGNMENT
4498           && TREE_CODE (type) == POINTER_TYPE
4499           && TREE_CODE (otype) == POINTER_TYPE
4500           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4501           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4502           /* Don't warn about opaque types, where the actual alignment
4503              restriction is unknown.  */
4504           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4505                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4506                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4507           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4508         warning_at (loc, OPT_Wcast_align,
4509                     "cast increases required alignment of target type");
4510
4511       if (TREE_CODE (type) == INTEGER_TYPE
4512           && TREE_CODE (otype) == POINTER_TYPE
4513           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4514       /* Unlike conversion of integers to pointers, where the
4515          warning is disabled for converting constants because
4516          of cases such as SIG_*, warn about converting constant
4517          pointers to integers. In some cases it may cause unwanted
4518          sign extension, and a warning is appropriate.  */
4519         warning_at (loc, OPT_Wpointer_to_int_cast,
4520                     "cast from pointer to integer of different size");
4521
4522       if (TREE_CODE (value) == CALL_EXPR
4523           && TREE_CODE (type) != TREE_CODE (otype))
4524         warning_at (loc, OPT_Wbad_function_cast,
4525                     "cast from function call of type %qT "
4526                     "to non-matching type %qT", otype, type);
4527
4528       if (TREE_CODE (type) == POINTER_TYPE
4529           && TREE_CODE (otype) == INTEGER_TYPE
4530           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4531           /* Don't warn about converting any constant.  */
4532           && !TREE_CONSTANT (value))
4533         warning_at (loc,
4534                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4535                     "of different size");
4536
4537       if (warn_strict_aliasing <= 2)
4538         strict_aliasing_warning (otype, type, expr);
4539
4540       /* If pedantic, warn for conversions between function and object
4541          pointer types, except for converting a null pointer constant
4542          to function pointer type.  */
4543       if (pedantic
4544           && TREE_CODE (type) == POINTER_TYPE
4545           && TREE_CODE (otype) == POINTER_TYPE
4546           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4547           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4548         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4549                  "conversion of function pointer to object pointer type");
4550
4551       if (pedantic
4552           && TREE_CODE (type) == POINTER_TYPE
4553           && TREE_CODE (otype) == POINTER_TYPE
4554           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4555           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4556           && !null_pointer_constant_p (value))
4557         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4558                  "conversion of object pointer to function pointer type");
4559
4560       ovalue = value;
4561       value = convert (type, value);
4562
4563       /* Ignore any integer overflow caused by the cast.  */
4564       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4565         {
4566           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4567             {
4568               if (!TREE_OVERFLOW (value))
4569                 {
4570                   /* Avoid clobbering a shared constant.  */
4571                   value = copy_node (value);
4572                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4573                 }
4574             }
4575           else if (TREE_OVERFLOW (value))
4576             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4577             value = build_int_cst_wide (TREE_TYPE (value),
4578                                         TREE_INT_CST_LOW (value),
4579                                         TREE_INT_CST_HIGH (value));
4580         }
4581     }
4582
4583   /* Don't let a cast be an lvalue.  */
4584   if (value == expr)
4585     value = non_lvalue_loc (loc, value);
4586
4587   /* Don't allow the results of casting to floating-point or complex
4588      types be confused with actual constants, or casts involving
4589      integer and pointer types other than direct integer-to-integer
4590      and integer-to-pointer be confused with integer constant
4591      expressions and null pointer constants.  */
4592   if (TREE_CODE (value) == REAL_CST
4593       || TREE_CODE (value) == COMPLEX_CST
4594       || (TREE_CODE (value) == INTEGER_CST
4595           && !((TREE_CODE (expr) == INTEGER_CST
4596                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4597                || TREE_CODE (expr) == REAL_CST
4598                || TREE_CODE (expr) == COMPLEX_CST)))
4599       value = build1 (NOP_EXPR, type, value);
4600
4601   if (CAN_HAVE_LOCATION_P (value))
4602     SET_EXPR_LOCATION (value, loc);
4603   return value;
4604 }
4605
4606 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4607    location of the open paren of the cast, or the position of the cast
4608    expr.  */
4609 tree
4610 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4611 {
4612   tree type;
4613   tree type_expr = NULL_TREE;
4614   bool type_expr_const = true;
4615   tree ret;
4616   int saved_wsp = warn_strict_prototypes;
4617
4618   /* This avoids warnings about unprototyped casts on
4619      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4620   if (TREE_CODE (expr) == INTEGER_CST)
4621     warn_strict_prototypes = 0;
4622   type = groktypename (type_name, &type_expr, &type_expr_const);
4623   warn_strict_prototypes = saved_wsp;
4624
4625   ret = build_c_cast (loc, type, expr);
4626   if (type_expr)
4627     {
4628       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4629       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4630       SET_EXPR_LOCATION (ret, loc);
4631     }
4632
4633   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4634     SET_EXPR_LOCATION (ret, loc);
4635
4636   /* C++ does not permits types to be defined in a cast.  */
4637   if (warn_cxx_compat && type_name->specs->tag_defined_p)
4638     warning_at (loc, OPT_Wc___compat,
4639                 "defining a type in a cast is invalid in C++");
4640
4641   return ret;
4642 }
4643 \f
4644 /* Build an assignment expression of lvalue LHS from value RHS.
4645    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4646    may differ from TREE_TYPE (LHS) for an enum bitfield.
4647    MODIFYCODE is the code for a binary operator that we use
4648    to combine the old value of LHS with RHS to get the new value.
4649    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4650    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4651    which may differ from TREE_TYPE (RHS) for an enum value.
4652
4653    LOCATION is the location of the MODIFYCODE operator.
4654    RHS_LOC is the location of the RHS.  */
4655
4656 tree
4657 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4658                    enum tree_code modifycode,
4659                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4660 {
4661   tree result;
4662   tree newrhs;
4663   tree rhs_semantic_type = NULL_TREE;
4664   tree lhstype = TREE_TYPE (lhs);
4665   tree olhstype = lhstype;
4666   bool npc;
4667
4668   /* Types that aren't fully specified cannot be used in assignments.  */
4669   lhs = require_complete_type (lhs);
4670
4671   /* Avoid duplicate error messages from operands that had errors.  */
4672   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4673     return error_mark_node;
4674
4675   if (!lvalue_or_else (lhs, lv_assign))
4676     return error_mark_node;
4677
4678   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4679     {
4680       rhs_semantic_type = TREE_TYPE (rhs);
4681       rhs = TREE_OPERAND (rhs, 0);
4682     }
4683
4684   newrhs = rhs;
4685
4686   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4687     {
4688       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4689                                       lhs_origtype, modifycode, rhs_loc, rhs,
4690                                       rhs_origtype);
4691       if (inner == error_mark_node)
4692         return error_mark_node;
4693       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4694                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4695       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4696       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4697       protected_set_expr_location (result, location);
4698       return result;
4699     }
4700
4701   /* If a binary op has been requested, combine the old LHS value with the RHS
4702      producing the value we should actually store into the LHS.  */
4703
4704   if (modifycode != NOP_EXPR)
4705     {
4706       lhs = c_fully_fold (lhs, false, NULL);
4707       lhs = stabilize_reference (lhs);
4708       newrhs = build_binary_op (location,
4709                                 modifycode, lhs, rhs, 1);
4710
4711       /* The original type of the right hand side is no longer
4712          meaningful.  */
4713       rhs_origtype = NULL_TREE;
4714     }
4715
4716   /* Give an error for storing in something that is 'const'.  */
4717
4718   if (TYPE_READONLY (lhstype)
4719       || ((TREE_CODE (lhstype) == RECORD_TYPE
4720            || TREE_CODE (lhstype) == UNION_TYPE)
4721           && C_TYPE_FIELDS_READONLY (lhstype)))
4722     {
4723       readonly_error (lhs, lv_assign);
4724       return error_mark_node;
4725     }
4726   else if (TREE_READONLY (lhs))
4727     readonly_warning (lhs, lv_assign);
4728
4729   /* If storing into a structure or union member,
4730      it has probably been given type `int'.
4731      Compute the type that would go with
4732      the actual amount of storage the member occupies.  */
4733
4734   if (TREE_CODE (lhs) == COMPONENT_REF
4735       && (TREE_CODE (lhstype) == INTEGER_TYPE
4736           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4737           || TREE_CODE (lhstype) == REAL_TYPE
4738           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4739     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4740
4741   /* If storing in a field that is in actuality a short or narrower than one,
4742      we must store in the field in its actual type.  */
4743
4744   if (lhstype != TREE_TYPE (lhs))
4745     {
4746       lhs = copy_node (lhs);
4747       TREE_TYPE (lhs) = lhstype;
4748     }
4749
4750   /* Issue -Wc++-compat warnings about an assignment to an enum type
4751      when LHS does not have its original type.  This happens for,
4752      e.g., an enum bitfield in a struct.  */
4753   if (warn_cxx_compat
4754       && lhs_origtype != NULL_TREE
4755       && lhs_origtype != lhstype
4756       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4757     {
4758       tree checktype = (rhs_origtype != NULL_TREE
4759                         ? rhs_origtype
4760                         : TREE_TYPE (rhs));
4761       if (checktype != error_mark_node
4762           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4763         warning_at (location, OPT_Wc___compat,
4764                     "enum conversion in assignment is invalid in C++");
4765     }
4766
4767   /* Convert new value to destination type.  Fold it first, then
4768      restore any excess precision information, for the sake of
4769      conversion warnings.  */
4770
4771   npc = null_pointer_constant_p (newrhs);
4772   newrhs = c_fully_fold (newrhs, false, NULL);
4773   if (rhs_semantic_type)
4774     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4775   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4776                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4777   if (TREE_CODE (newrhs) == ERROR_MARK)
4778     return error_mark_node;
4779
4780   /* Emit ObjC write barrier, if necessary.  */
4781   if (c_dialect_objc () && flag_objc_gc)
4782     {
4783       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4784       if (result)
4785         {
4786           protected_set_expr_location (result, location);
4787           return result;
4788         }
4789     }
4790
4791   /* Scan operands.  */
4792
4793   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4794   TREE_SIDE_EFFECTS (result) = 1;
4795   protected_set_expr_location (result, location);
4796
4797   /* If we got the LHS in a different type for storing in,
4798      convert the result back to the nominal type of LHS
4799      so that the value we return always has the same type
4800      as the LHS argument.  */
4801
4802   if (olhstype == TREE_TYPE (result))
4803     return result;
4804
4805   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
4806                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
4807   protected_set_expr_location (result, location);
4808   return result;
4809 }
4810 \f
4811 /* Convert value RHS to type TYPE as preparation for an assignment to
4812    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
4813    original type of RHS; this differs from TREE_TYPE (RHS) for enum
4814    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
4815    constant before any folding.
4816    The real work of conversion is done by `convert'.
4817    The purpose of this function is to generate error messages
4818    for assignments that are not allowed in C.
4819    ERRTYPE says whether it is argument passing, assignment,
4820    initialization or return.
4821
4822    LOCATION is the location of the RHS.
4823    FUNCTION is a tree for the function being called.
4824    PARMNUM is the number of the argument, for printing in error messages.  */
4825
4826 static tree
4827 convert_for_assignment (location_t location, tree type, tree rhs,
4828                         tree origtype, enum impl_conv errtype,
4829                         bool null_pointer_constant, tree fundecl,
4830                         tree function, int parmnum)
4831 {
4832   enum tree_code codel = TREE_CODE (type);
4833   tree orig_rhs = rhs;
4834   tree rhstype;
4835   enum tree_code coder;
4836   tree rname = NULL_TREE;
4837   bool objc_ok = false;
4838
4839   if (errtype == ic_argpass)
4840     {
4841       tree selector;
4842       /* Change pointer to function to the function itself for
4843          diagnostics.  */
4844       if (TREE_CODE (function) == ADDR_EXPR
4845           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4846         function = TREE_OPERAND (function, 0);
4847
4848       /* Handle an ObjC selector specially for diagnostics.  */
4849       selector = objc_message_selector ();
4850       rname = function;
4851       if (selector && parmnum > 2)
4852         {
4853           rname = selector;
4854           parmnum -= 2;
4855         }
4856     }
4857
4858   /* This macro is used to emit diagnostics to ensure that all format
4859      strings are complete sentences, visible to gettext and checked at
4860      compile time.  */
4861 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4862   do {                                                                   \
4863     switch (errtype)                                                     \
4864       {                                                                  \
4865       case ic_argpass:                                                   \
4866         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4867           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4868                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4869                   "expected %qT but argument is of type %qT",            \
4870                   type, rhstype);                                        \
4871         break;                                                           \
4872       case ic_assign:                                                    \
4873         pedwarn (LOCATION, OPT, AS);                                     \
4874         break;                                                           \
4875       case ic_init:                                                      \
4876         pedwarn (LOCATION, OPT, IN);                                     \
4877         break;                                                           \
4878       case ic_return:                                                    \
4879         pedwarn (LOCATION, OPT, RE);                                     \
4880         break;                                                           \
4881       default:                                                           \
4882         gcc_unreachable ();                                              \
4883       }                                                                  \
4884   } while (0)
4885
4886   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4887     rhs = TREE_OPERAND (rhs, 0);
4888
4889   rhstype = TREE_TYPE (rhs);
4890   coder = TREE_CODE (rhstype);
4891
4892   if (coder == ERROR_MARK)
4893     return error_mark_node;
4894
4895   if (c_dialect_objc ())
4896     {
4897       int parmno;
4898
4899       switch (errtype)
4900         {
4901         case ic_return:
4902           parmno = 0;
4903           break;
4904
4905         case ic_assign:
4906           parmno = -1;
4907           break;
4908
4909         case ic_init:
4910           parmno = -2;
4911           break;
4912
4913         default:
4914           parmno = parmnum;
4915           break;
4916         }
4917
4918       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4919     }
4920
4921   if (warn_cxx_compat)
4922     {
4923       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
4924       if (checktype != error_mark_node
4925           && TREE_CODE (type) == ENUMERAL_TYPE
4926           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
4927         {
4928           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
4929                                G_("enum conversion when passing argument "
4930                                   "%d of %qE is invalid in C++"),
4931                                G_("enum conversion in assignment is "
4932                                   "invalid in C++"),
4933                                G_("enum conversion in initialization is "
4934                                   "invalid in C++"),
4935                                G_("enum conversion in return is "
4936                                   "invalid in C++"));
4937         }
4938     }
4939
4940   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4941     return rhs;
4942
4943   if (coder == VOID_TYPE)
4944     {
4945       /* Except for passing an argument to an unprototyped function,
4946          this is a constraint violation.  When passing an argument to
4947          an unprototyped function, it is compile-time undefined;
4948          making it a constraint in that case was rejected in
4949          DR#252.  */
4950       error_at (location, "void value not ignored as it ought to be");
4951       return error_mark_node;
4952     }
4953   rhs = require_complete_type (rhs);
4954   if (rhs == error_mark_node)
4955     return error_mark_node;
4956   /* A type converts to a reference to it.
4957      This code doesn't fully support references, it's just for the
4958      special case of va_start and va_copy.  */
4959   if (codel == REFERENCE_TYPE
4960       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4961     {
4962       if (!lvalue_p (rhs))
4963         {
4964           error_at (location, "cannot pass rvalue to reference parameter");
4965           return error_mark_node;
4966         }
4967       if (!c_mark_addressable (rhs))
4968         return error_mark_node;
4969       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4970       SET_EXPR_LOCATION (rhs, location);
4971
4972       /* We already know that these two types are compatible, but they
4973          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4974          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4975          likely to be va_list, a typedef to __builtin_va_list, which
4976          is different enough that it will cause problems later.  */
4977       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4978         {
4979           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4980           SET_EXPR_LOCATION (rhs, location);
4981         }
4982
4983       rhs = build1 (NOP_EXPR, type, rhs);
4984       SET_EXPR_LOCATION (rhs, location);
4985       return rhs;
4986     }
4987   /* Some types can interconvert without explicit casts.  */
4988   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4989            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4990     return convert (type, rhs);
4991   /* Arithmetic types all interconvert, and enum is treated like int.  */
4992   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4993             || codel == FIXED_POINT_TYPE
4994             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4995             || codel == BOOLEAN_TYPE)
4996            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4997                || coder == FIXED_POINT_TYPE
4998                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4999                || coder == BOOLEAN_TYPE))
5000     {
5001       tree ret;
5002       bool save = in_late_binary_op;
5003       if (codel == BOOLEAN_TYPE)
5004         in_late_binary_op = true;
5005       ret = convert_and_check (type, orig_rhs);
5006       if (codel == BOOLEAN_TYPE)
5007         in_late_binary_op = save;
5008       return ret;
5009     }
5010
5011   /* Aggregates in different TUs might need conversion.  */
5012   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
5013       && codel == coder
5014       && comptypes (type, rhstype))
5015     return convert_and_check (type, rhs);
5016
5017   /* Conversion to a transparent union or record from its member types.
5018      This applies only to function arguments.  */
5019   if (((codel == UNION_TYPE || codel == RECORD_TYPE)
5020       && TYPE_TRANSPARENT_AGGR (type))
5021       && errtype == ic_argpass)
5022     {
5023       tree memb, marginal_memb = NULL_TREE;
5024
5025       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
5026         {
5027           tree memb_type = TREE_TYPE (memb);
5028
5029           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
5030                          TYPE_MAIN_VARIANT (rhstype)))
5031             break;
5032
5033           if (TREE_CODE (memb_type) != POINTER_TYPE)
5034             continue;
5035
5036           if (coder == POINTER_TYPE)
5037             {
5038               tree ttl = TREE_TYPE (memb_type);
5039               tree ttr = TREE_TYPE (rhstype);
5040
5041               /* Any non-function converts to a [const][volatile] void *
5042                  and vice versa; otherwise, targets must be the same.
5043                  Meanwhile, the lhs target must have all the qualifiers of
5044                  the rhs.  */
5045               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5046                   || comp_target_types (location, memb_type, rhstype))
5047                 {
5048                   /* If this type won't generate any warnings, use it.  */
5049                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
5050                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
5051                            && TREE_CODE (ttl) == FUNCTION_TYPE)
5052                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5053                              == TYPE_QUALS (ttr))
5054                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5055                              == TYPE_QUALS (ttl))))
5056                     break;
5057
5058                   /* Keep looking for a better type, but remember this one.  */
5059                   if (!marginal_memb)
5060                     marginal_memb = memb;
5061                 }
5062             }
5063
5064           /* Can convert integer zero to any pointer type.  */
5065           if (null_pointer_constant)
5066             {
5067               rhs = null_pointer_node;
5068               break;
5069             }
5070         }
5071
5072       if (memb || marginal_memb)
5073         {
5074           if (!memb)
5075             {
5076               /* We have only a marginally acceptable member type;
5077                  it needs a warning.  */
5078               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
5079               tree ttr = TREE_TYPE (rhstype);
5080
5081               /* Const and volatile mean something different for function
5082                  types, so the usual warnings are not appropriate.  */
5083               if (TREE_CODE (ttr) == FUNCTION_TYPE
5084                   && TREE_CODE (ttl) == FUNCTION_TYPE)
5085                 {
5086                   /* Because const and volatile on functions are
5087                      restrictions that say the function will not do
5088                      certain things, it is okay to use a const or volatile
5089                      function where an ordinary one is wanted, but not
5090                      vice-versa.  */
5091                   if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5092                       & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5093                     WARN_FOR_ASSIGNMENT (location, 0,
5094                                          G_("passing argument %d of %qE "
5095                                             "makes qualified function "
5096                                             "pointer from unqualified"),
5097                                          G_("assignment makes qualified "
5098                                             "function pointer from "
5099                                             "unqualified"),
5100                                          G_("initialization makes qualified "
5101                                             "function pointer from "
5102                                             "unqualified"),
5103                                          G_("return makes qualified function "
5104                                             "pointer from unqualified"));
5105                 }
5106               else if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5107                        & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5108                 WARN_FOR_ASSIGNMENT (location, 0,
5109                                      G_("passing argument %d of %qE discards "
5110                                         "qualifiers from pointer target type"),
5111                                      G_("assignment discards qualifiers "
5112                                         "from pointer target type"),
5113                                      G_("initialization discards qualifiers "
5114                                         "from pointer target type"),
5115                                      G_("return discards qualifiers from "
5116                                         "pointer target type"));
5117
5118               memb = marginal_memb;
5119             }
5120
5121           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
5122             pedwarn (location, OPT_pedantic,
5123                      "ISO C prohibits argument conversion to union type");
5124
5125           rhs = fold_convert_loc (location, TREE_TYPE (memb), rhs);
5126           return build_constructor_single (type, memb, rhs);
5127         }
5128     }
5129
5130   /* Conversions among pointers */
5131   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
5132            && (coder == codel))
5133     {
5134       tree ttl = TREE_TYPE (type);
5135       tree ttr = TREE_TYPE (rhstype);
5136       tree mvl = ttl;
5137       tree mvr = ttr;
5138       bool is_opaque_pointer;
5139       int target_cmp = 0;   /* Cache comp_target_types () result.  */
5140       addr_space_t asl;
5141       addr_space_t asr;
5142
5143       if (TREE_CODE (mvl) != ARRAY_TYPE)
5144         mvl = TYPE_MAIN_VARIANT (mvl);
5145       if (TREE_CODE (mvr) != ARRAY_TYPE)
5146         mvr = TYPE_MAIN_VARIANT (mvr);
5147       /* Opaque pointers are treated like void pointers.  */
5148       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
5149
5150       /* C++ does not allow the implicit conversion void* -> T*.  However,
5151          for the purpose of reducing the number of false positives, we
5152          tolerate the special case of
5153
5154                 int *p = NULL;
5155
5156          where NULL is typically defined in C to be '(void *) 0'.  */
5157       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
5158         warning_at (location, OPT_Wc___compat,
5159                     "request for implicit conversion "
5160                     "from %qT to %qT not permitted in C++", rhstype, type);
5161
5162       /* See if the pointers point to incompatible address spaces.  */
5163       asl = TYPE_ADDR_SPACE (ttl);
5164       asr = TYPE_ADDR_SPACE (ttr);
5165       if (!null_pointer_constant_p (rhs)
5166           && asr != asl && !targetm.addr_space.subset_p (asr, asl))
5167         {
5168           switch (errtype)
5169             {
5170             case ic_argpass:
5171               error_at (location, "passing argument %d of %qE from pointer to "
5172                         "non-enclosed address space", parmnum, rname);
5173               break;
5174             case ic_assign:
5175               error_at (location, "assignment from pointer to "
5176                         "non-enclosed address space");
5177               break;
5178             case ic_init:
5179               error_at (location, "initialization from pointer to "
5180                         "non-enclosed address space");
5181               break;
5182             case ic_return:
5183               error_at (location, "return from pointer to "
5184                         "non-enclosed address space");
5185               break;
5186             default:
5187               gcc_unreachable ();
5188             }
5189           return error_mark_node;
5190         }
5191
5192       /* Check if the right-hand side has a format attribute but the
5193          left-hand side doesn't.  */
5194       if (warn_missing_format_attribute
5195           && check_missing_format_attribute (type, rhstype))
5196         {
5197           switch (errtype)
5198           {
5199           case ic_argpass:
5200             warning_at (location, OPT_Wmissing_format_attribute,
5201                         "argument %d of %qE might be "
5202                         "a candidate for a format attribute",
5203                         parmnum, rname);
5204             break;
5205           case ic_assign:
5206             warning_at (location, OPT_Wmissing_format_attribute,
5207                         "assignment left-hand side might be "
5208                         "a candidate for a format attribute");
5209             break;
5210           case ic_init:
5211             warning_at (location, OPT_Wmissing_format_attribute,
5212                         "initialization left-hand side might be "
5213                         "a candidate for a format attribute");
5214             break;
5215           case ic_return:
5216             warning_at (location, OPT_Wmissing_format_attribute,
5217                         "return type might be "
5218                         "a candidate for a format attribute");
5219             break;
5220           default:
5221             gcc_unreachable ();
5222           }
5223         }
5224
5225       /* Any non-function converts to a [const][volatile] void *
5226          and vice versa; otherwise, targets must be the same.
5227          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5228       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5229           || (target_cmp = comp_target_types (location, type, rhstype))
5230           || is_opaque_pointer
5231           || (c_common_unsigned_type (mvl)
5232               == c_common_unsigned_type (mvr)))
5233         {
5234           if (pedantic
5235               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5236                   ||
5237                   (VOID_TYPE_P (ttr)
5238                    && !null_pointer_constant
5239                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5240             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5241                                  G_("ISO C forbids passing argument %d of "
5242                                     "%qE between function pointer "
5243                                     "and %<void *%>"),
5244                                  G_("ISO C forbids assignment between "
5245                                     "function pointer and %<void *%>"),
5246                                  G_("ISO C forbids initialization between "
5247                                     "function pointer and %<void *%>"),
5248                                  G_("ISO C forbids return between function "
5249                                     "pointer and %<void *%>"));
5250           /* Const and volatile mean something different for function types,
5251              so the usual warnings are not appropriate.  */
5252           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5253                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5254             {
5255               if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5256                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5257                 {
5258                   /* Types differing only by the presence of the 'volatile'
5259                      qualifier are acceptable if the 'volatile' has been added
5260                      in by the Objective-C EH machinery.  */
5261                   if (!objc_type_quals_match (ttl, ttr))
5262                     WARN_FOR_ASSIGNMENT (location, 0,
5263                                          G_("passing argument %d of %qE discards "
5264                                             "qualifiers from pointer target type"),
5265                                          G_("assignment discards qualifiers "
5266                                             "from pointer target type"),
5267                                          G_("initialization discards qualifiers "
5268                                             "from pointer target type"),
5269                                          G_("return discards qualifiers from "
5270                                             "pointer target type"));
5271                 }
5272               /* If this is not a case of ignoring a mismatch in signedness,
5273                  no warning.  */
5274               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5275                        || target_cmp)
5276                 ;
5277               /* If there is a mismatch, do warn.  */
5278               else if (warn_pointer_sign)
5279                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5280                                      G_("pointer targets in passing argument "
5281                                         "%d of %qE differ in signedness"),
5282                                      G_("pointer targets in assignment "
5283                                         "differ in signedness"),
5284                                      G_("pointer targets in initialization "
5285                                         "differ in signedness"),
5286                                      G_("pointer targets in return differ "
5287                                         "in signedness"));
5288             }
5289           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5290                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5291             {
5292               /* Because const and volatile on functions are restrictions
5293                  that say the function will not do certain things,
5294                  it is okay to use a const or volatile function
5295                  where an ordinary one is wanted, but not vice-versa.  */
5296               if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5297                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5298                 WARN_FOR_ASSIGNMENT (location, 0,
5299                                      G_("passing argument %d of %qE makes "
5300                                         "qualified function pointer "
5301                                         "from unqualified"),
5302                                      G_("assignment makes qualified function "
5303                                         "pointer from unqualified"),
5304                                      G_("initialization makes qualified "
5305                                         "function pointer from unqualified"),
5306                                      G_("return makes qualified function "
5307                                         "pointer from unqualified"));
5308             }
5309         }
5310       else
5311         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5312         if (!objc_ok)
5313           WARN_FOR_ASSIGNMENT (location, 0,
5314                                G_("passing argument %d of %qE from "
5315                                   "incompatible pointer type"),
5316                                G_("assignment from incompatible pointer type"),
5317                                G_("initialization from incompatible "
5318                                   "pointer type"),
5319                                G_("return from incompatible pointer type"));
5320
5321       return convert (type, rhs);
5322     }
5323   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5324     {
5325       /* ??? This should not be an error when inlining calls to
5326          unprototyped functions.  */
5327       error_at (location, "invalid use of non-lvalue array");
5328       return error_mark_node;
5329     }
5330   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5331     {
5332       /* An explicit constant 0 can convert to a pointer,
5333          or one that results from arithmetic, even including
5334          a cast to integer type.  */
5335       if (!null_pointer_constant)
5336         WARN_FOR_ASSIGNMENT (location, 0,
5337                              G_("passing argument %d of %qE makes "
5338                                 "pointer from integer without a cast"),
5339                              G_("assignment makes pointer from integer "
5340                                 "without a cast"),
5341                              G_("initialization makes pointer from "
5342                                 "integer without a cast"),
5343                              G_("return makes pointer from integer "
5344                                 "without a cast"));
5345
5346       return convert (type, rhs);
5347     }
5348   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5349     {
5350       WARN_FOR_ASSIGNMENT (location, 0,
5351                            G_("passing argument %d of %qE makes integer "
5352                               "from pointer without a cast"),
5353                            G_("assignment makes integer from pointer "
5354                               "without a cast"),
5355                            G_("initialization makes integer from pointer "
5356                               "without a cast"),
5357                            G_("return makes integer from pointer "
5358                               "without a cast"));
5359       return convert (type, rhs);
5360     }
5361   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5362     {
5363       tree ret;
5364       bool save = in_late_binary_op;
5365       in_late_binary_op = true;
5366       ret = convert (type, rhs);
5367       in_late_binary_op = save;
5368       return ret;
5369     }
5370
5371   switch (errtype)
5372     {
5373     case ic_argpass:
5374       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5375       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5376               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5377               "expected %qT but argument is of type %qT", type, rhstype);
5378       break;
5379     case ic_assign:
5380       error_at (location, "incompatible types when assigning to type %qT from "
5381                 "type %qT", type, rhstype);
5382       break;
5383     case ic_init:
5384       error_at (location,
5385                 "incompatible types when initializing type %qT using type %qT",
5386                 type, rhstype);
5387       break;
5388     case ic_return:
5389       error_at (location,
5390                 "incompatible types when returning type %qT but %qT was "
5391                 "expected", rhstype, type);
5392       break;
5393     default:
5394       gcc_unreachable ();
5395     }
5396
5397   return error_mark_node;
5398 }
5399 \f
5400 /* If VALUE is a compound expr all of whose expressions are constant, then
5401    return its value.  Otherwise, return error_mark_node.
5402
5403    This is for handling COMPOUND_EXPRs as initializer elements
5404    which is allowed with a warning when -pedantic is specified.  */
5405
5406 static tree
5407 valid_compound_expr_initializer (tree value, tree endtype)
5408 {
5409   if (TREE_CODE (value) == COMPOUND_EXPR)
5410     {
5411       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5412           == error_mark_node)
5413         return error_mark_node;
5414       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5415                                               endtype);
5416     }
5417   else if (!initializer_constant_valid_p (value, endtype))
5418     return error_mark_node;
5419   else
5420     return value;
5421 }
5422 \f
5423 /* Perform appropriate conversions on the initial value of a variable,
5424    store it in the declaration DECL,
5425    and print any error messages that are appropriate.
5426    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5427    If the init is invalid, store an ERROR_MARK.
5428
5429    INIT_LOC is the location of the initial value.  */
5430
5431 void
5432 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5433 {
5434   tree value, type;
5435   bool npc = false;
5436
5437   /* If variable's type was invalidly declared, just ignore it.  */
5438
5439   type = TREE_TYPE (decl);
5440   if (TREE_CODE (type) == ERROR_MARK)
5441     return;
5442
5443   /* Digest the specified initializer into an expression.  */
5444
5445   if (init)
5446     npc = null_pointer_constant_p (init);
5447   value = digest_init (init_loc, type, init, origtype, npc,
5448                        true, TREE_STATIC (decl));
5449
5450   /* Store the expression if valid; else report error.  */
5451
5452   if (!in_system_header
5453       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5454     warning (OPT_Wtraditional, "traditional C rejects automatic "
5455              "aggregate initialization");
5456
5457   DECL_INITIAL (decl) = value;
5458
5459   /* ANSI wants warnings about out-of-range constant initializers.  */
5460   STRIP_TYPE_NOPS (value);
5461   if (TREE_STATIC (decl))
5462     constant_expression_warning (value);
5463
5464   /* Check if we need to set array size from compound literal size.  */
5465   if (TREE_CODE (type) == ARRAY_TYPE
5466       && TYPE_DOMAIN (type) == 0
5467       && value != error_mark_node)
5468     {
5469       tree inside_init = init;
5470
5471       STRIP_TYPE_NOPS (inside_init);
5472       inside_init = fold (inside_init);
5473
5474       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5475         {
5476           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5477
5478           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5479             {
5480               /* For int foo[] = (int [3]){1}; we need to set array size
5481                  now since later on array initializer will be just the
5482                  brace enclosed list of the compound literal.  */
5483               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5484               TREE_TYPE (decl) = type;
5485               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5486               layout_type (type);
5487               layout_decl (cldecl, 0);
5488             }
5489         }
5490     }
5491 }
5492 \f
5493 /* Methods for storing and printing names for error messages.  */
5494
5495 /* Implement a spelling stack that allows components of a name to be pushed
5496    and popped.  Each element on the stack is this structure.  */
5497
5498 struct spelling
5499 {
5500   int kind;
5501   union
5502     {
5503       unsigned HOST_WIDE_INT i;
5504       const char *s;
5505     } u;
5506 };
5507
5508 #define SPELLING_STRING 1
5509 #define SPELLING_MEMBER 2
5510 #define SPELLING_BOUNDS 3
5511
5512 static struct spelling *spelling;       /* Next stack element (unused).  */
5513 static struct spelling *spelling_base;  /* Spelling stack base.  */
5514 static int spelling_size;               /* Size of the spelling stack.  */
5515
5516 /* Macros to save and restore the spelling stack around push_... functions.
5517    Alternative to SAVE_SPELLING_STACK.  */
5518
5519 #define SPELLING_DEPTH() (spelling - spelling_base)
5520 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5521
5522 /* Push an element on the spelling stack with type KIND and assign VALUE
5523    to MEMBER.  */
5524
5525 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5526 {                                                                       \
5527   int depth = SPELLING_DEPTH ();                                        \
5528                                                                         \
5529   if (depth >= spelling_size)                                           \
5530     {                                                                   \
5531       spelling_size += 10;                                              \
5532       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5533                                   spelling_size);                       \
5534       RESTORE_SPELLING_DEPTH (depth);                                   \
5535     }                                                                   \
5536                                                                         \
5537   spelling->kind = (KIND);                                              \
5538   spelling->MEMBER = (VALUE);                                           \
5539   spelling++;                                                           \
5540 }
5541
5542 /* Push STRING on the stack.  Printed literally.  */
5543
5544 static void
5545 push_string (const char *string)
5546 {
5547   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5548 }
5549
5550 /* Push a member name on the stack.  Printed as '.' STRING.  */
5551
5552 static void
5553 push_member_name (tree decl)
5554 {
5555   const char *const string
5556     = (DECL_NAME (decl)
5557        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5558        : _("<anonymous>"));
5559   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5560 }
5561
5562 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5563
5564 static void
5565 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5566 {
5567   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5568 }
5569
5570 /* Compute the maximum size in bytes of the printed spelling.  */
5571
5572 static int
5573 spelling_length (void)
5574 {
5575   int size = 0;
5576   struct spelling *p;
5577
5578   for (p = spelling_base; p < spelling; p++)
5579     {
5580       if (p->kind == SPELLING_BOUNDS)
5581         size += 25;
5582       else
5583         size += strlen (p->u.s) + 1;
5584     }
5585
5586   return size;
5587 }
5588
5589 /* Print the spelling to BUFFER and return it.  */
5590
5591 static char *
5592 print_spelling (char *buffer)
5593 {
5594   char *d = buffer;
5595   struct spelling *p;
5596
5597   for (p = spelling_base; p < spelling; p++)
5598     if (p->kind == SPELLING_BOUNDS)
5599       {
5600         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5601         d += strlen (d);
5602       }
5603     else
5604       {
5605         const char *s;
5606         if (p->kind == SPELLING_MEMBER)
5607           *d++ = '.';
5608         for (s = p->u.s; (*d = *s++); d++)
5609           ;
5610       }
5611   *d++ = '\0';
5612   return buffer;
5613 }
5614
5615 /* Issue an error message for a bad initializer component.
5616    MSGID identifies the message.
5617    The component name is taken from the spelling stack.  */
5618
5619 void
5620 error_init (const char *msgid)
5621 {
5622   char *ofwhat;
5623
5624   error ("%s", _(msgid));
5625   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5626   if (*ofwhat)
5627     error ("(near initialization for %qs)", ofwhat);
5628 }
5629
5630 /* Issue a pedantic warning for a bad initializer component.  OPT is
5631    the option OPT_* (from options.h) controlling this warning or 0 if
5632    it is unconditionally given.  MSGID identifies the message.  The
5633    component name is taken from the spelling stack.  */
5634
5635 void
5636 pedwarn_init (location_t location, int opt, const char *msgid)
5637 {
5638   char *ofwhat;
5639
5640   pedwarn (location, opt, "%s", _(msgid));
5641   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5642   if (*ofwhat)
5643     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5644 }
5645
5646 /* Issue a warning for a bad initializer component.
5647
5648    OPT is the OPT_W* value corresponding to the warning option that
5649    controls this warning.  MSGID identifies the message.  The
5650    component name is taken from the spelling stack.  */
5651
5652 static void
5653 warning_init (int opt, const char *msgid)
5654 {
5655   char *ofwhat;
5656
5657   warning (opt, "%s", _(msgid));
5658   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5659   if (*ofwhat)
5660     warning (opt, "(near initialization for %qs)", ofwhat);
5661 }
5662 \f
5663 /* If TYPE is an array type and EXPR is a parenthesized string
5664    constant, warn if pedantic that EXPR is being used to initialize an
5665    object of type TYPE.  */
5666
5667 void
5668 maybe_warn_string_init (tree type, struct c_expr expr)
5669 {
5670   if (pedantic
5671       && TREE_CODE (type) == ARRAY_TYPE
5672       && TREE_CODE (expr.value) == STRING_CST
5673       && expr.original_code != STRING_CST)
5674     pedwarn_init (input_location, OPT_pedantic,
5675                   "array initialized from parenthesized string constant");
5676 }
5677
5678 /* Digest the parser output INIT as an initializer for type TYPE.
5679    Return a C expression of type TYPE to represent the initial value.
5680
5681    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5682
5683    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5684
5685    If INIT is a string constant, STRICT_STRING is true if it is
5686    unparenthesized or we should not warn here for it being parenthesized.
5687    For other types of INIT, STRICT_STRING is not used.
5688
5689    INIT_LOC is the location of the INIT.
5690
5691    REQUIRE_CONSTANT requests an error if non-constant initializers or
5692    elements are seen.  */
5693
5694 static tree
5695 digest_init (location_t init_loc, tree type, tree init, tree origtype,
5696              bool null_pointer_constant, bool strict_string,
5697              int require_constant)
5698 {
5699   enum tree_code code = TREE_CODE (type);
5700   tree inside_init = init;
5701   tree semantic_type = NULL_TREE;
5702   bool maybe_const = true;
5703
5704   if (type == error_mark_node
5705       || !init
5706       || init == error_mark_node
5707       || TREE_TYPE (init) == error_mark_node)
5708     return error_mark_node;
5709
5710   STRIP_TYPE_NOPS (inside_init);
5711
5712   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5713     {
5714       semantic_type = TREE_TYPE (inside_init);
5715       inside_init = TREE_OPERAND (inside_init, 0);
5716     }
5717   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5718   inside_init = decl_constant_value_for_optimization (inside_init);
5719
5720   /* Initialization of an array of chars from a string constant
5721      optionally enclosed in braces.  */
5722
5723   if (code == ARRAY_TYPE && inside_init
5724       && TREE_CODE (inside_init) == STRING_CST)
5725     {
5726       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5727       /* Note that an array could be both an array of character type
5728          and an array of wchar_t if wchar_t is signed char or unsigned
5729          char.  */
5730       bool char_array = (typ1 == char_type_node
5731                          || typ1 == signed_char_type_node
5732                          || typ1 == unsigned_char_type_node);
5733       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5734       bool char16_array = !!comptypes (typ1, char16_type_node);
5735       bool char32_array = !!comptypes (typ1, char32_type_node);
5736
5737       if (char_array || wchar_array || char16_array || char32_array)
5738         {
5739           struct c_expr expr;
5740           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5741           expr.value = inside_init;
5742           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5743           expr.original_type = NULL;
5744           maybe_warn_string_init (type, expr);
5745
5746           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
5747             pedwarn_init (init_loc, OPT_pedantic,
5748                           "initialization of a flexible array member");
5749
5750           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5751                          TYPE_MAIN_VARIANT (type)))
5752             return inside_init;
5753
5754           if (char_array)
5755             {
5756               if (typ2 != char_type_node)
5757                 {
5758                   error_init ("char-array initialized from wide string");
5759                   return error_mark_node;
5760                 }
5761             }
5762           else
5763             {
5764               if (typ2 == char_type_node)
5765                 {
5766                   error_init ("wide character array initialized from non-wide "
5767                               "string");
5768                   return error_mark_node;
5769                 }
5770               else if (!comptypes(typ1, typ2))
5771                 {
5772                   error_init ("wide character array initialized from "
5773                               "incompatible wide string");
5774                   return error_mark_node;
5775                 }
5776             }
5777
5778           TREE_TYPE (inside_init) = type;
5779           if (TYPE_DOMAIN (type) != 0
5780               && TYPE_SIZE (type) != 0
5781               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
5782             {
5783               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
5784
5785               /* Subtract the size of a single (possibly wide) character
5786                  because it's ok to ignore the terminating null char
5787                  that is counted in the length of the constant.  */
5788               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5789                                         (len
5790                                          - (TYPE_PRECISION (typ1)
5791                                             / BITS_PER_UNIT))))
5792                 pedwarn_init (init_loc, 0,
5793                               ("initializer-string for array of chars "
5794                                "is too long"));
5795               else if (warn_cxx_compat
5796                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
5797                 warning_at (init_loc, OPT_Wc___compat,
5798                             ("initializer-string for array chars "
5799                              "is too long for C++"));
5800             }
5801
5802           return inside_init;
5803         }
5804       else if (INTEGRAL_TYPE_P (typ1))
5805         {
5806           error_init ("array of inappropriate type initialized "
5807                       "from string constant");
5808           return error_mark_node;
5809         }
5810     }
5811
5812   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5813      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5814      below and handle as a constructor.  */
5815   if (code == VECTOR_TYPE
5816       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5817       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5818       && TREE_CONSTANT (inside_init))
5819     {
5820       if (TREE_CODE (inside_init) == VECTOR_CST
5821           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5822                         TYPE_MAIN_VARIANT (type)))
5823         return inside_init;
5824
5825       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5826         {
5827           unsigned HOST_WIDE_INT ix;
5828           tree value;
5829           bool constant_p = true;
5830
5831           /* Iterate through elements and check if all constructor
5832              elements are *_CSTs.  */
5833           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5834             if (!CONSTANT_CLASS_P (value))
5835               {
5836                 constant_p = false;
5837                 break;
5838               }
5839
5840           if (constant_p)
5841             return build_vector_from_ctor (type,
5842                                            CONSTRUCTOR_ELTS (inside_init));
5843         }
5844     }
5845
5846   if (warn_sequence_point)
5847     verify_sequence_points (inside_init);
5848
5849   /* Any type can be initialized
5850      from an expression of the same type, optionally with braces.  */
5851
5852   if (inside_init && TREE_TYPE (inside_init) != 0
5853       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5854                      TYPE_MAIN_VARIANT (type))
5855           || (code == ARRAY_TYPE
5856               && comptypes (TREE_TYPE (inside_init), type))
5857           || (code == VECTOR_TYPE
5858               && comptypes (TREE_TYPE (inside_init), type))
5859           || (code == POINTER_TYPE
5860               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5861               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5862                             TREE_TYPE (type)))))
5863     {
5864       if (code == POINTER_TYPE)
5865         {
5866           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5867             {
5868               if (TREE_CODE (inside_init) == STRING_CST
5869                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5870                 inside_init = array_to_pointer_conversion
5871                   (init_loc, inside_init);
5872               else
5873                 {
5874                   error_init ("invalid use of non-lvalue array");
5875                   return error_mark_node;
5876                 }
5877             }
5878         }
5879
5880       if (code == VECTOR_TYPE)
5881         /* Although the types are compatible, we may require a
5882            conversion.  */
5883         inside_init = convert (type, inside_init);
5884
5885       if (require_constant
5886           && (code == VECTOR_TYPE || !flag_isoc99)
5887           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5888         {
5889           /* As an extension, allow initializing objects with static storage
5890              duration with compound literals (which are then treated just as
5891              the brace enclosed list they contain).  Also allow this for
5892              vectors, as we can only assign them with compound literals.  */
5893           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5894           inside_init = DECL_INITIAL (decl);
5895         }
5896
5897       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5898           && TREE_CODE (inside_init) != CONSTRUCTOR)
5899         {
5900           error_init ("array initialized from non-constant array expression");
5901           return error_mark_node;
5902         }
5903
5904       /* Compound expressions can only occur here if -pedantic or
5905          -pedantic-errors is specified.  In the later case, we always want
5906          an error.  In the former case, we simply want a warning.  */
5907       if (require_constant && pedantic
5908           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5909         {
5910           inside_init
5911             = valid_compound_expr_initializer (inside_init,
5912                                                TREE_TYPE (inside_init));
5913           if (inside_init == error_mark_node)
5914             error_init ("initializer element is not constant");
5915           else
5916             pedwarn_init (init_loc, OPT_pedantic,
5917                           "initializer element is not constant");
5918           if (flag_pedantic_errors)
5919             inside_init = error_mark_node;
5920         }
5921       else if (require_constant
5922                && !initializer_constant_valid_p (inside_init,
5923                                                  TREE_TYPE (inside_init)))
5924         {
5925           error_init ("initializer element is not constant");
5926           inside_init = error_mark_node;
5927         }
5928       else if (require_constant && !maybe_const)
5929         pedwarn_init (init_loc, 0,
5930                       "initializer element is not a constant expression");
5931
5932       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5933       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5934         inside_init = convert_for_assignment (init_loc, type, inside_init,
5935                                               origtype,
5936                                               ic_init, null_pointer_constant,
5937                                               NULL_TREE, NULL_TREE, 0);
5938       return inside_init;
5939     }
5940
5941   /* Handle scalar types, including conversions.  */
5942
5943   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5944       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5945       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5946     {
5947       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5948           && (TREE_CODE (init) == STRING_CST
5949               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5950         inside_init = init = array_to_pointer_conversion (init_loc, init);
5951       if (semantic_type)
5952         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5953                               inside_init);
5954       inside_init
5955         = convert_for_assignment (init_loc, type, inside_init, origtype,
5956                                   ic_init, null_pointer_constant,
5957                                   NULL_TREE, NULL_TREE, 0);
5958
5959       /* Check to see if we have already given an error message.  */
5960       if (inside_init == error_mark_node)
5961         ;
5962       else if (require_constant && !TREE_CONSTANT (inside_init))
5963         {
5964           error_init ("initializer element is not constant");
5965           inside_init = error_mark_node;
5966         }
5967       else if (require_constant
5968                && !initializer_constant_valid_p (inside_init,
5969                                                  TREE_TYPE (inside_init)))
5970         {
5971           error_init ("initializer element is not computable at load time");
5972           inside_init = error_mark_node;
5973         }
5974       else if (require_constant && !maybe_const)
5975         pedwarn_init (init_loc, 0,
5976                       "initializer element is not a constant expression");
5977
5978       return inside_init;
5979     }
5980
5981   /* Come here only for records and arrays.  */
5982
5983   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5984     {
5985       error_init ("variable-sized object may not be initialized");
5986       return error_mark_node;
5987     }
5988
5989   error_init ("invalid initializer");
5990   return error_mark_node;
5991 }
5992 \f
5993 /* Handle initializers that use braces.  */
5994
5995 /* Type of object we are accumulating a constructor for.
5996    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5997 static tree constructor_type;
5998
5999 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
6000    left to fill.  */
6001 static tree constructor_fields;
6002
6003 /* For an ARRAY_TYPE, this is the specified index
6004    at which to store the next element we get.  */
6005 static tree constructor_index;
6006
6007 /* For an ARRAY_TYPE, this is the maximum index.  */
6008 static tree constructor_max_index;
6009
6010 /* For a RECORD_TYPE, this is the first field not yet written out.  */
6011 static tree constructor_unfilled_fields;
6012
6013 /* For an ARRAY_TYPE, this is the index of the first element
6014    not yet written out.  */
6015 static tree constructor_unfilled_index;
6016
6017 /* In a RECORD_TYPE, the byte index of the next consecutive field.
6018    This is so we can generate gaps between fields, when appropriate.  */
6019 static tree constructor_bit_index;
6020
6021 /* If we are saving up the elements rather than allocating them,
6022    this is the list of elements so far (in reverse order,
6023    most recent first).  */
6024 static VEC(constructor_elt,gc) *constructor_elements;
6025
6026 /* 1 if constructor should be incrementally stored into a constructor chain,
6027    0 if all the elements should be kept in AVL tree.  */
6028 static int constructor_incremental;
6029
6030 /* 1 if so far this constructor's elements are all compile-time constants.  */
6031 static int constructor_constant;
6032
6033 /* 1 if so far this constructor's elements are all valid address constants.  */
6034 static int constructor_simple;
6035
6036 /* 1 if this constructor has an element that cannot be part of a
6037    constant expression.  */
6038 static int constructor_nonconst;
6039
6040 /* 1 if this constructor is erroneous so far.  */
6041 static int constructor_erroneous;
6042
6043 /* Structure for managing pending initializer elements, organized as an
6044    AVL tree.  */
6045
6046 struct init_node
6047 {
6048   struct init_node *left, *right;
6049   struct init_node *parent;
6050   int balance;
6051   tree purpose;
6052   tree value;
6053   tree origtype;
6054 };
6055
6056 /* Tree of pending elements at this constructor level.
6057    These are elements encountered out of order
6058    which belong at places we haven't reached yet in actually
6059    writing the output.
6060    Will never hold tree nodes across GC runs.  */
6061 static struct init_node *constructor_pending_elts;
6062
6063 /* The SPELLING_DEPTH of this constructor.  */
6064 static int constructor_depth;
6065
6066 /* DECL node for which an initializer is being read.
6067    0 means we are reading a constructor expression
6068    such as (struct foo) {...}.  */
6069 static tree constructor_decl;
6070
6071 /* Nonzero if this is an initializer for a top-level decl.  */
6072 static int constructor_top_level;
6073
6074 /* Nonzero if there were any member designators in this initializer.  */
6075 static int constructor_designated;
6076
6077 /* Nesting depth of designator list.  */
6078 static int designator_depth;
6079
6080 /* Nonzero if there were diagnosed errors in this designator list.  */
6081 static int designator_erroneous;
6082
6083 \f
6084 /* This stack has a level for each implicit or explicit level of
6085    structuring in the initializer, including the outermost one.  It
6086    saves the values of most of the variables above.  */
6087
6088 struct constructor_range_stack;
6089
6090 struct constructor_stack
6091 {
6092   struct constructor_stack *next;
6093   tree type;
6094   tree fields;
6095   tree index;
6096   tree max_index;
6097   tree unfilled_index;
6098   tree unfilled_fields;
6099   tree bit_index;
6100   VEC(constructor_elt,gc) *elements;
6101   struct init_node *pending_elts;
6102   int offset;
6103   int depth;
6104   /* If value nonzero, this value should replace the entire
6105      constructor at this level.  */
6106   struct c_expr replacement_value;
6107   struct constructor_range_stack *range_stack;
6108   char constant;
6109   char simple;
6110   char nonconst;
6111   char implicit;
6112   char erroneous;
6113   char outer;
6114   char incremental;
6115   char designated;
6116 };
6117
6118 static struct constructor_stack *constructor_stack;
6119
6120 /* This stack represents designators from some range designator up to
6121    the last designator in the list.  */
6122
6123 struct constructor_range_stack
6124 {
6125   struct constructor_range_stack *next, *prev;
6126   struct constructor_stack *stack;
6127   tree range_start;
6128   tree index;
6129   tree range_end;
6130   tree fields;
6131 };
6132
6133 static struct constructor_range_stack *constructor_range_stack;
6134
6135 /* This stack records separate initializers that are nested.
6136    Nested initializers can't happen in ANSI C, but GNU C allows them
6137    in cases like { ... (struct foo) { ... } ... }.  */
6138
6139 struct initializer_stack
6140 {
6141   struct initializer_stack *next;
6142   tree decl;
6143   struct constructor_stack *constructor_stack;
6144   struct constructor_range_stack *constructor_range_stack;
6145   VEC(constructor_elt,gc) *elements;
6146   struct spelling *spelling;
6147   struct spelling *spelling_base;
6148   int spelling_size;
6149   char top_level;
6150   char require_constant_value;
6151   char require_constant_elements;
6152 };
6153
6154 static struct initializer_stack *initializer_stack;
6155 \f
6156 /* Prepare to parse and output the initializer for variable DECL.  */
6157
6158 void
6159 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
6160 {
6161   const char *locus;
6162   struct initializer_stack *p = XNEW (struct initializer_stack);
6163
6164   p->decl = constructor_decl;
6165   p->require_constant_value = require_constant_value;
6166   p->require_constant_elements = require_constant_elements;
6167   p->constructor_stack = constructor_stack;
6168   p->constructor_range_stack = constructor_range_stack;
6169   p->elements = constructor_elements;
6170   p->spelling = spelling;
6171   p->spelling_base = spelling_base;
6172   p->spelling_size = spelling_size;
6173   p->top_level = constructor_top_level;
6174   p->next = initializer_stack;
6175   initializer_stack = p;
6176
6177   constructor_decl = decl;
6178   constructor_designated = 0;
6179   constructor_top_level = top_level;
6180
6181   if (decl != 0 && decl != error_mark_node)
6182     {
6183       require_constant_value = TREE_STATIC (decl);
6184       require_constant_elements
6185         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
6186            /* For a scalar, you can always use any value to initialize,
6187               even within braces.  */
6188            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
6189                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
6190                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
6191                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
6192       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
6193     }
6194   else
6195     {
6196       require_constant_value = 0;
6197       require_constant_elements = 0;
6198       locus = _("(anonymous)");
6199     }
6200
6201   constructor_stack = 0;
6202   constructor_range_stack = 0;
6203
6204   missing_braces_mentioned = 0;
6205
6206   spelling_base = 0;
6207   spelling_size = 0;
6208   RESTORE_SPELLING_DEPTH (0);
6209
6210   if (locus)
6211     push_string (locus);
6212 }
6213
6214 void
6215 finish_init (void)
6216 {
6217   struct initializer_stack *p = initializer_stack;
6218
6219   /* Free the whole constructor stack of this initializer.  */
6220   while (constructor_stack)
6221     {
6222       struct constructor_stack *q = constructor_stack;
6223       constructor_stack = q->next;
6224       free (q);
6225     }
6226
6227   gcc_assert (!constructor_range_stack);
6228
6229   /* Pop back to the data of the outer initializer (if any).  */
6230   free (spelling_base);
6231
6232   constructor_decl = p->decl;
6233   require_constant_value = p->require_constant_value;
6234   require_constant_elements = p->require_constant_elements;
6235   constructor_stack = p->constructor_stack;
6236   constructor_range_stack = p->constructor_range_stack;
6237   constructor_elements = p->elements;
6238   spelling = p->spelling;
6239   spelling_base = p->spelling_base;
6240   spelling_size = p->spelling_size;
6241   constructor_top_level = p->top_level;
6242   initializer_stack = p->next;
6243   free (p);
6244 }
6245 \f
6246 /* Call here when we see the initializer is surrounded by braces.
6247    This is instead of a call to push_init_level;
6248    it is matched by a call to pop_init_level.
6249
6250    TYPE is the type to initialize, for a constructor expression.
6251    For an initializer for a decl, TYPE is zero.  */
6252
6253 void
6254 really_start_incremental_init (tree type)
6255 {
6256   struct constructor_stack *p = XNEW (struct constructor_stack);
6257
6258   if (type == 0)
6259     type = TREE_TYPE (constructor_decl);
6260
6261   if (TREE_CODE (type) == VECTOR_TYPE
6262       && TYPE_VECTOR_OPAQUE (type))
6263     error ("opaque vector types cannot be initialized");
6264
6265   p->type = constructor_type;
6266   p->fields = constructor_fields;
6267   p->index = constructor_index;
6268   p->max_index = constructor_max_index;
6269   p->unfilled_index = constructor_unfilled_index;
6270   p->unfilled_fields = constructor_unfilled_fields;
6271   p->bit_index = constructor_bit_index;
6272   p->elements = constructor_elements;
6273   p->constant = constructor_constant;
6274   p->simple = constructor_simple;
6275   p->nonconst = constructor_nonconst;
6276   p->erroneous = constructor_erroneous;
6277   p->pending_elts = constructor_pending_elts;
6278   p->depth = constructor_depth;
6279   p->replacement_value.value = 0;
6280   p->replacement_value.original_code = ERROR_MARK;
6281   p->replacement_value.original_type = NULL;
6282   p->implicit = 0;
6283   p->range_stack = 0;
6284   p->outer = 0;
6285   p->incremental = constructor_incremental;
6286   p->designated = constructor_designated;
6287   p->next = 0;
6288   constructor_stack = p;
6289
6290   constructor_constant = 1;
6291   constructor_simple = 1;
6292   constructor_nonconst = 0;
6293   constructor_depth = SPELLING_DEPTH ();
6294   constructor_elements = 0;
6295   constructor_pending_elts = 0;
6296   constructor_type = type;
6297   constructor_incremental = 1;
6298   constructor_designated = 0;
6299   designator_depth = 0;
6300   designator_erroneous = 0;
6301
6302   if (TREE_CODE (constructor_type) == RECORD_TYPE
6303       || TREE_CODE (constructor_type) == UNION_TYPE)
6304     {
6305       constructor_fields = TYPE_FIELDS (constructor_type);
6306       /* Skip any nameless bit fields at the beginning.  */
6307       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6308              && DECL_NAME (constructor_fields) == 0)
6309         constructor_fields = TREE_CHAIN (constructor_fields);
6310
6311       constructor_unfilled_fields = constructor_fields;
6312       constructor_bit_index = bitsize_zero_node;
6313     }
6314   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6315     {
6316       if (TYPE_DOMAIN (constructor_type))
6317         {
6318           constructor_max_index
6319             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6320
6321           /* Detect non-empty initializations of zero-length arrays.  */
6322           if (constructor_max_index == NULL_TREE
6323               && TYPE_SIZE (constructor_type))
6324             constructor_max_index = build_int_cst (NULL_TREE, -1);
6325
6326           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6327              to initialize VLAs will cause a proper error; avoid tree
6328              checking errors as well by setting a safe value.  */
6329           if (constructor_max_index
6330               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6331             constructor_max_index = build_int_cst (NULL_TREE, -1);
6332
6333           constructor_index
6334             = convert (bitsizetype,
6335                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6336         }
6337       else
6338         {
6339           constructor_index = bitsize_zero_node;
6340           constructor_max_index = NULL_TREE;
6341         }
6342
6343       constructor_unfilled_index = constructor_index;
6344     }
6345   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6346     {
6347       /* Vectors are like simple fixed-size arrays.  */
6348       constructor_max_index =
6349         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6350       constructor_index = bitsize_zero_node;
6351       constructor_unfilled_index = constructor_index;
6352     }
6353   else
6354     {
6355       /* Handle the case of int x = {5}; */
6356       constructor_fields = constructor_type;
6357       constructor_unfilled_fields = constructor_type;
6358     }
6359 }
6360 \f
6361 /* Push down into a subobject, for initialization.
6362    If this is for an explicit set of braces, IMPLICIT is 0.
6363    If it is because the next element belongs at a lower level,
6364    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6365
6366 void
6367 push_init_level (int implicit)
6368 {
6369   struct constructor_stack *p;
6370   tree value = NULL_TREE;
6371
6372   /* If we've exhausted any levels that didn't have braces,
6373      pop them now.  If implicit == 1, this will have been done in
6374      process_init_element; do not repeat it here because in the case
6375      of excess initializers for an empty aggregate this leads to an
6376      infinite cycle of popping a level and immediately recreating
6377      it.  */
6378   if (implicit != 1)
6379     {
6380       while (constructor_stack->implicit)
6381         {
6382           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6383                || TREE_CODE (constructor_type) == UNION_TYPE)
6384               && constructor_fields == 0)
6385             process_init_element (pop_init_level (1), true);
6386           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6387                    && constructor_max_index
6388                    && tree_int_cst_lt (constructor_max_index,
6389                                        constructor_index))
6390             process_init_element (pop_init_level (1), true);
6391           else
6392             break;
6393         }
6394     }
6395
6396   /* Unless this is an explicit brace, we need to preserve previous
6397      content if any.  */
6398   if (implicit)
6399     {
6400       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6401            || TREE_CODE (constructor_type) == UNION_TYPE)
6402           && constructor_fields)
6403         value = find_init_member (constructor_fields);
6404       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6405         value = find_init_member (constructor_index);
6406     }
6407
6408   p = XNEW (struct constructor_stack);
6409   p->type = constructor_type;
6410   p->fields = constructor_fields;
6411   p->index = constructor_index;
6412   p->max_index = constructor_max_index;
6413   p->unfilled_index = constructor_unfilled_index;
6414   p->unfilled_fields = constructor_unfilled_fields;
6415   p->bit_index = constructor_bit_index;
6416   p->elements = constructor_elements;
6417   p->constant = constructor_constant;
6418   p->simple = constructor_simple;
6419   p->nonconst = constructor_nonconst;
6420   p->erroneous = constructor_erroneous;
6421   p->pending_elts = constructor_pending_elts;
6422   p->depth = constructor_depth;
6423   p->replacement_value.value = 0;
6424   p->replacement_value.original_code = ERROR_MARK;
6425   p->replacement_value.original_type = NULL;
6426   p->implicit = implicit;
6427   p->outer = 0;
6428   p->incremental = constructor_incremental;
6429   p->designated = constructor_designated;
6430   p->next = constructor_stack;
6431   p->range_stack = 0;
6432   constructor_stack = p;
6433
6434   constructor_constant = 1;
6435   constructor_simple = 1;
6436   constructor_nonconst = 0;
6437   constructor_depth = SPELLING_DEPTH ();
6438   constructor_elements = 0;
6439   constructor_incremental = 1;
6440   constructor_designated = 0;
6441   constructor_pending_elts = 0;
6442   if (!implicit)
6443     {
6444       p->range_stack = constructor_range_stack;
6445       constructor_range_stack = 0;
6446       designator_depth = 0;
6447       designator_erroneous = 0;
6448     }
6449
6450   /* Don't die if an entire brace-pair level is superfluous
6451      in the containing level.  */
6452   if (constructor_type == 0)
6453     ;
6454   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6455            || TREE_CODE (constructor_type) == UNION_TYPE)
6456     {
6457       /* Don't die if there are extra init elts at the end.  */
6458       if (constructor_fields == 0)
6459         constructor_type = 0;
6460       else
6461         {
6462           constructor_type = TREE_TYPE (constructor_fields);
6463           push_member_name (constructor_fields);
6464           constructor_depth++;
6465         }
6466     }
6467   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6468     {
6469       constructor_type = TREE_TYPE (constructor_type);
6470       push_array_bounds (tree_low_cst (constructor_index, 1));
6471       constructor_depth++;
6472     }
6473
6474   if (constructor_type == 0)
6475     {
6476       error_init ("extra brace group at end of initializer");
6477       constructor_fields = 0;
6478       constructor_unfilled_fields = 0;
6479       return;
6480     }
6481
6482   if (value && TREE_CODE (value) == CONSTRUCTOR)
6483     {
6484       constructor_constant = TREE_CONSTANT (value);
6485       constructor_simple = TREE_STATIC (value);
6486       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6487       constructor_elements = CONSTRUCTOR_ELTS (value);
6488       if (!VEC_empty (constructor_elt, constructor_elements)
6489           && (TREE_CODE (constructor_type) == RECORD_TYPE
6490               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6491         set_nonincremental_init ();
6492     }
6493
6494   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6495     {
6496       missing_braces_mentioned = 1;
6497       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6498     }
6499
6500   if (TREE_CODE (constructor_type) == RECORD_TYPE
6501            || TREE_CODE (constructor_type) == UNION_TYPE)
6502     {
6503       constructor_fields = TYPE_FIELDS (constructor_type);
6504       /* Skip any nameless bit fields at the beginning.  */
6505       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6506              && DECL_NAME (constructor_fields) == 0)
6507         constructor_fields = TREE_CHAIN (constructor_fields);
6508
6509       constructor_unfilled_fields = constructor_fields;
6510       constructor_bit_index = bitsize_zero_node;
6511     }
6512   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6513     {
6514       /* Vectors are like simple fixed-size arrays.  */
6515       constructor_max_index =
6516         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6517       constructor_index = convert (bitsizetype, integer_zero_node);
6518       constructor_unfilled_index = constructor_index;
6519     }
6520   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6521     {
6522       if (TYPE_DOMAIN (constructor_type))
6523         {
6524           constructor_max_index
6525             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6526
6527           /* Detect non-empty initializations of zero-length arrays.  */
6528           if (constructor_max_index == NULL_TREE
6529               && TYPE_SIZE (constructor_type))
6530             constructor_max_index = build_int_cst (NULL_TREE, -1);
6531
6532           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6533              to initialize VLAs will cause a proper error; avoid tree
6534              checking errors as well by setting a safe value.  */
6535           if (constructor_max_index
6536               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6537             constructor_max_index = build_int_cst (NULL_TREE, -1);
6538
6539           constructor_index
6540             = convert (bitsizetype,
6541                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6542         }
6543       else
6544         constructor_index = bitsize_zero_node;
6545
6546       constructor_unfilled_index = constructor_index;
6547       if (value && TREE_CODE (value) == STRING_CST)
6548         {
6549           /* We need to split the char/wchar array into individual
6550              characters, so that we don't have to special case it
6551              everywhere.  */
6552           set_nonincremental_init_from_string (value);
6553         }
6554     }
6555   else
6556     {
6557       if (constructor_type != error_mark_node)
6558         warning_init (0, "braces around scalar initializer");
6559       constructor_fields = constructor_type;
6560       constructor_unfilled_fields = constructor_type;
6561     }
6562 }
6563
6564 /* At the end of an implicit or explicit brace level,
6565    finish up that level of constructor.  If a single expression
6566    with redundant braces initialized that level, return the
6567    c_expr structure for that expression.  Otherwise, the original_code
6568    element is set to ERROR_MARK.
6569    If we were outputting the elements as they are read, return 0 as the value
6570    from inner levels (process_init_element ignores that),
6571    but return error_mark_node as the value from the outermost level
6572    (that's what we want to put in DECL_INITIAL).
6573    Otherwise, return a CONSTRUCTOR expression as the value.  */
6574
6575 struct c_expr
6576 pop_init_level (int implicit)
6577 {
6578   struct constructor_stack *p;
6579   struct c_expr ret;
6580   ret.value = 0;
6581   ret.original_code = ERROR_MARK;
6582   ret.original_type = NULL;
6583
6584   if (implicit == 0)
6585     {
6586       /* When we come to an explicit close brace,
6587          pop any inner levels that didn't have explicit braces.  */
6588       while (constructor_stack->implicit)
6589         process_init_element (pop_init_level (1), true);
6590
6591       gcc_assert (!constructor_range_stack);
6592     }
6593
6594   /* Now output all pending elements.  */
6595   constructor_incremental = 1;
6596   output_pending_init_elements (1);
6597
6598   p = constructor_stack;
6599
6600   /* Error for initializing a flexible array member, or a zero-length
6601      array member in an inappropriate context.  */
6602   if (constructor_type && constructor_fields
6603       && TREE_CODE (constructor_type) == ARRAY_TYPE
6604       && TYPE_DOMAIN (constructor_type)
6605       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6606     {
6607       /* Silently discard empty initializations.  The parser will
6608          already have pedwarned for empty brackets.  */
6609       if (integer_zerop (constructor_unfilled_index))
6610         constructor_type = NULL_TREE;
6611       else
6612         {
6613           gcc_assert (!TYPE_SIZE (constructor_type));
6614
6615           if (constructor_depth > 2)
6616             error_init ("initialization of flexible array member in a nested context");
6617           else
6618             pedwarn_init (input_location, OPT_pedantic,
6619                           "initialization of a flexible array member");
6620
6621           /* We have already issued an error message for the existence
6622              of a flexible array member not at the end of the structure.
6623              Discard the initializer so that we do not die later.  */
6624           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6625             constructor_type = NULL_TREE;
6626         }
6627     }
6628
6629   /* Warn when some struct elements are implicitly initialized to zero.  */
6630   if (warn_missing_field_initializers
6631       && constructor_type
6632       && TREE_CODE (constructor_type) == RECORD_TYPE
6633       && constructor_unfilled_fields)
6634     {
6635         /* Do not warn for flexible array members or zero-length arrays.  */
6636         while (constructor_unfilled_fields
6637                && (!DECL_SIZE (constructor_unfilled_fields)
6638                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6639           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6640
6641         /* Do not warn if this level of the initializer uses member
6642            designators; it is likely to be deliberate.  */
6643         if (constructor_unfilled_fields && !constructor_designated)
6644           {
6645             push_member_name (constructor_unfilled_fields);
6646             warning_init (OPT_Wmissing_field_initializers,
6647                           "missing initializer");
6648             RESTORE_SPELLING_DEPTH (constructor_depth);
6649           }
6650     }
6651
6652   /* Pad out the end of the structure.  */
6653   if (p->replacement_value.value)
6654     /* If this closes a superfluous brace pair,
6655        just pass out the element between them.  */
6656     ret = p->replacement_value;
6657   else if (constructor_type == 0)
6658     ;
6659   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6660            && TREE_CODE (constructor_type) != UNION_TYPE
6661            && TREE_CODE (constructor_type) != ARRAY_TYPE
6662            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6663     {
6664       /* A nonincremental scalar initializer--just return
6665          the element, after verifying there is just one.  */
6666       if (VEC_empty (constructor_elt,constructor_elements))
6667         {
6668           if (!constructor_erroneous)
6669             error_init ("empty scalar initializer");
6670           ret.value = error_mark_node;
6671         }
6672       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6673         {
6674           error_init ("extra elements in scalar initializer");
6675           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6676         }
6677       else
6678         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6679     }
6680   else
6681     {
6682       if (constructor_erroneous)
6683         ret.value = error_mark_node;
6684       else
6685         {
6686           ret.value = build_constructor (constructor_type,
6687                                          constructor_elements);
6688           if (constructor_constant)
6689             TREE_CONSTANT (ret.value) = 1;
6690           if (constructor_constant && constructor_simple)
6691             TREE_STATIC (ret.value) = 1;
6692           if (constructor_nonconst)
6693             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6694         }
6695     }
6696
6697   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6698     {
6699       if (constructor_nonconst)
6700         ret.original_code = C_MAYBE_CONST_EXPR;
6701       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6702         ret.original_code = ERROR_MARK;
6703     }
6704
6705   constructor_type = p->type;
6706   constructor_fields = p->fields;
6707   constructor_index = p->index;
6708   constructor_max_index = p->max_index;
6709   constructor_unfilled_index = p->unfilled_index;
6710   constructor_unfilled_fields = p->unfilled_fields;
6711   constructor_bit_index = p->bit_index;
6712   constructor_elements = p->elements;
6713   constructor_constant = p->constant;
6714   constructor_simple = p->simple;
6715   constructor_nonconst = p->nonconst;
6716   constructor_erroneous = p->erroneous;
6717   constructor_incremental = p->incremental;
6718   constructor_designated = p->designated;
6719   constructor_pending_elts = p->pending_elts;
6720   constructor_depth = p->depth;
6721   if (!p->implicit)
6722     constructor_range_stack = p->range_stack;
6723   RESTORE_SPELLING_DEPTH (constructor_depth);
6724
6725   constructor_stack = p->next;
6726   free (p);
6727
6728   if (ret.value == 0 && constructor_stack == 0)
6729     ret.value = error_mark_node;
6730   return ret;
6731 }
6732
6733 /* Common handling for both array range and field name designators.
6734    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6735
6736 static int
6737 set_designator (int array)
6738 {
6739   tree subtype;
6740   enum tree_code subcode;
6741
6742   /* Don't die if an entire brace-pair level is superfluous
6743      in the containing level.  */
6744   if (constructor_type == 0)
6745     return 1;
6746
6747   /* If there were errors in this designator list already, bail out
6748      silently.  */
6749   if (designator_erroneous)
6750     return 1;
6751
6752   if (!designator_depth)
6753     {
6754       gcc_assert (!constructor_range_stack);
6755
6756       /* Designator list starts at the level of closest explicit
6757          braces.  */
6758       while (constructor_stack->implicit)
6759         process_init_element (pop_init_level (1), true);
6760       constructor_designated = 1;
6761       return 0;
6762     }
6763
6764   switch (TREE_CODE (constructor_type))
6765     {
6766     case  RECORD_TYPE:
6767     case  UNION_TYPE:
6768       subtype = TREE_TYPE (constructor_fields);
6769       if (subtype != error_mark_node)
6770         subtype = TYPE_MAIN_VARIANT (subtype);
6771       break;
6772     case ARRAY_TYPE:
6773       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6774       break;
6775     default:
6776       gcc_unreachable ();
6777     }
6778
6779   subcode = TREE_CODE (subtype);
6780   if (array && subcode != ARRAY_TYPE)
6781     {
6782       error_init ("array index in non-array initializer");
6783       return 1;
6784     }
6785   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6786     {
6787       error_init ("field name not in record or union initializer");
6788       return 1;
6789     }
6790
6791   constructor_designated = 1;
6792   push_init_level (2);
6793   return 0;
6794 }
6795
6796 /* If there are range designators in designator list, push a new designator
6797    to constructor_range_stack.  RANGE_END is end of such stack range or
6798    NULL_TREE if there is no range designator at this level.  */
6799
6800 static void
6801 push_range_stack (tree range_end)
6802 {
6803   struct constructor_range_stack *p;
6804
6805   p = GGC_NEW (struct constructor_range_stack);
6806   p->prev = constructor_range_stack;
6807   p->next = 0;
6808   p->fields = constructor_fields;
6809   p->range_start = constructor_index;
6810   p->index = constructor_index;
6811   p->stack = constructor_stack;
6812   p->range_end = range_end;
6813   if (constructor_range_stack)
6814     constructor_range_stack->next = p;
6815   constructor_range_stack = p;
6816 }
6817
6818 /* Within an array initializer, specify the next index to be initialized.
6819    FIRST is that index.  If LAST is nonzero, then initialize a range
6820    of indices, running from FIRST through LAST.  */
6821
6822 void
6823 set_init_index (tree first, tree last)
6824 {
6825   if (set_designator (1))
6826     return;
6827
6828   designator_erroneous = 1;
6829
6830   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6831       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6832     {
6833       error_init ("array index in initializer not of integer type");
6834       return;
6835     }
6836
6837   if (TREE_CODE (first) != INTEGER_CST)
6838     {
6839       first = c_fully_fold (first, false, NULL);
6840       if (TREE_CODE (first) == INTEGER_CST)
6841         pedwarn_init (input_location, OPT_pedantic,
6842                       "array index in initializer is not "
6843                       "an integer constant expression");
6844     }
6845
6846   if (last && TREE_CODE (last) != INTEGER_CST)
6847     {
6848       last = c_fully_fold (last, false, NULL);
6849       if (TREE_CODE (last) == INTEGER_CST)
6850         pedwarn_init (input_location, OPT_pedantic,
6851                       "array index in initializer is not "
6852                       "an integer constant expression");
6853     }
6854
6855   if (TREE_CODE (first) != INTEGER_CST)
6856     error_init ("nonconstant array index in initializer");
6857   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6858     error_init ("nonconstant array index in initializer");
6859   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6860     error_init ("array index in non-array initializer");
6861   else if (tree_int_cst_sgn (first) == -1)
6862     error_init ("array index in initializer exceeds array bounds");
6863   else if (constructor_max_index
6864            && tree_int_cst_lt (constructor_max_index, first))
6865     error_init ("array index in initializer exceeds array bounds");
6866   else
6867     {
6868       constant_expression_warning (first);
6869       if (last)
6870         constant_expression_warning (last);
6871       constructor_index = convert (bitsizetype, first);
6872
6873       if (last)
6874         {
6875           if (tree_int_cst_equal (first, last))
6876             last = 0;
6877           else if (tree_int_cst_lt (last, first))
6878             {
6879               error_init ("empty index range in initializer");
6880               last = 0;
6881             }
6882           else
6883             {
6884               last = convert (bitsizetype, last);
6885               if (constructor_max_index != 0
6886                   && tree_int_cst_lt (constructor_max_index, last))
6887                 {
6888                   error_init ("array index range in initializer exceeds array bounds");
6889                   last = 0;
6890                 }
6891             }
6892         }
6893
6894       designator_depth++;
6895       designator_erroneous = 0;
6896       if (constructor_range_stack || last)
6897         push_range_stack (last);
6898     }
6899 }
6900
6901 /* Within a struct initializer, specify the next field to be initialized.  */
6902
6903 void
6904 set_init_label (tree fieldname)
6905 {
6906   tree tail;
6907
6908   if (set_designator (0))
6909     return;
6910
6911   designator_erroneous = 1;
6912
6913   if (TREE_CODE (constructor_type) != RECORD_TYPE
6914       && TREE_CODE (constructor_type) != UNION_TYPE)
6915     {
6916       error_init ("field name not in record or union initializer");
6917       return;
6918     }
6919
6920   for (tail = TYPE_FIELDS (constructor_type); tail;
6921        tail = TREE_CHAIN (tail))
6922     {
6923       if (DECL_NAME (tail) == fieldname)
6924         break;
6925     }
6926
6927   if (tail == 0)
6928     error ("unknown field %qE specified in initializer", fieldname);
6929   else
6930     {
6931       constructor_fields = tail;
6932       designator_depth++;
6933       designator_erroneous = 0;
6934       if (constructor_range_stack)
6935         push_range_stack (NULL_TREE);
6936     }
6937 }
6938 \f
6939 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6940    identifies the initializer, either array index or field in a structure.
6941    VALUE is the value of that index or field.  If ORIGTYPE is not
6942    NULL_TREE, it is the original type of VALUE.
6943
6944    IMPLICIT is true if value comes from pop_init_level (1),
6945    the new initializer has been merged with the existing one
6946    and thus no warnings should be emitted about overriding an
6947    existing initializer.  */
6948
6949 static void
6950 add_pending_init (tree purpose, tree value, tree origtype, bool implicit)
6951 {
6952   struct init_node *p, **q, *r;
6953
6954   q = &constructor_pending_elts;
6955   p = 0;
6956
6957   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6958     {
6959       while (*q != 0)
6960         {
6961           p = *q;
6962           if (tree_int_cst_lt (purpose, p->purpose))
6963             q = &p->left;
6964           else if (tree_int_cst_lt (p->purpose, purpose))
6965             q = &p->right;
6966           else
6967             {
6968               if (!implicit)
6969                 {
6970                   if (TREE_SIDE_EFFECTS (p->value))
6971                     warning_init (0, "initialized field with side-effects overwritten");
6972                   else if (warn_override_init)
6973                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6974                 }
6975               p->value = value;
6976               p->origtype = origtype;
6977               return;
6978             }
6979         }
6980     }
6981   else
6982     {
6983       tree bitpos;
6984
6985       bitpos = bit_position (purpose);
6986       while (*q != NULL)
6987         {
6988           p = *q;
6989           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6990             q = &p->left;
6991           else if (p->purpose != purpose)
6992             q = &p->right;
6993           else
6994             {
6995               if (!implicit)
6996                 {
6997                   if (TREE_SIDE_EFFECTS (p->value))
6998                     warning_init (0, "initialized field with side-effects overwritten");
6999                   else if (warn_override_init)
7000                     warning_init (OPT_Woverride_init, "initialized field overwritten");
7001                 }
7002               p->value = value;
7003               p->origtype = origtype;
7004               return;
7005             }
7006         }
7007     }
7008
7009   r = GGC_NEW (struct init_node);
7010   r->purpose = purpose;
7011   r->value = value;
7012   r->origtype = origtype;
7013
7014   *q = r;
7015   r->parent = p;
7016   r->left = 0;
7017   r->right = 0;
7018   r->balance = 0;
7019
7020   while (p)
7021     {
7022       struct init_node *s;
7023
7024       if (r == p->left)
7025         {
7026           if (p->balance == 0)
7027             p->balance = -1;
7028           else if (p->balance < 0)
7029             {
7030               if (r->balance < 0)
7031                 {
7032                   /* L rotation.  */
7033                   p->left = r->right;
7034                   if (p->left)
7035                     p->left->parent = p;
7036                   r->right = p;
7037
7038                   p->balance = 0;
7039                   r->balance = 0;
7040
7041                   s = p->parent;
7042                   p->parent = r;
7043                   r->parent = s;
7044                   if (s)
7045                     {
7046                       if (s->left == p)
7047                         s->left = r;
7048                       else
7049                         s->right = r;
7050                     }
7051                   else
7052                     constructor_pending_elts = r;
7053                 }
7054               else
7055                 {
7056                   /* LR rotation.  */
7057                   struct init_node *t = r->right;
7058
7059                   r->right = t->left;
7060                   if (r->right)
7061                     r->right->parent = r;
7062                   t->left = r;
7063
7064                   p->left = t->right;
7065                   if (p->left)
7066                     p->left->parent = p;
7067                   t->right = p;
7068
7069                   p->balance = t->balance < 0;
7070                   r->balance = -(t->balance > 0);
7071                   t->balance = 0;
7072
7073                   s = p->parent;
7074                   p->parent = t;
7075                   r->parent = t;
7076                   t->parent = s;
7077                   if (s)
7078                     {
7079                       if (s->left == p)
7080                         s->left = t;
7081                       else
7082                         s->right = t;
7083                     }
7084                   else
7085                     constructor_pending_elts = t;
7086                 }
7087               break;
7088             }
7089           else
7090             {
7091               /* p->balance == +1; growth of left side balances the node.  */
7092               p->balance = 0;
7093               break;
7094             }
7095         }
7096       else /* r == p->right */
7097         {
7098           if (p->balance == 0)
7099             /* Growth propagation from right side.  */
7100             p->balance++;
7101           else if (p->balance > 0)
7102             {
7103               if (r->balance > 0)
7104                 {
7105                   /* R rotation.  */
7106                   p->right = r->left;
7107                   if (p->right)
7108                     p->right->parent = p;
7109                   r->left = p;
7110
7111                   p->balance = 0;
7112                   r->balance = 0;
7113
7114                   s = p->parent;
7115                   p->parent = r;
7116                   r->parent = s;
7117                   if (s)
7118                     {
7119                       if (s->left == p)
7120                         s->left = r;
7121                       else
7122                         s->right = r;
7123                     }
7124                   else
7125                     constructor_pending_elts = r;
7126                 }
7127               else /* r->balance == -1 */
7128                 {
7129                   /* RL rotation */
7130                   struct init_node *t = r->left;
7131
7132                   r->left = t->right;
7133                   if (r->left)
7134                     r->left->parent = r;
7135                   t->right = r;
7136
7137                   p->right = t->left;
7138                   if (p->right)
7139                     p->right->parent = p;
7140                   t->left = p;
7141
7142                   r->balance = (t->balance < 0);
7143                   p->balance = -(t->balance > 0);
7144                   t->balance = 0;
7145
7146                   s = p->parent;
7147                   p->parent = t;
7148                   r->parent = t;
7149                   t->parent = s;
7150                   if (s)
7151                     {
7152                       if (s->left == p)
7153                         s->left = t;
7154                       else
7155                         s->right = t;
7156                     }
7157                   else
7158                     constructor_pending_elts = t;
7159                 }
7160               break;
7161             }
7162           else
7163             {
7164               /* p->balance == -1; growth of right side balances the node.  */
7165               p->balance = 0;
7166               break;
7167             }
7168         }
7169
7170       r = p;
7171       p = p->parent;
7172     }
7173 }
7174
7175 /* Build AVL tree from a sorted chain.  */
7176
7177 static void
7178 set_nonincremental_init (void)
7179 {
7180   unsigned HOST_WIDE_INT ix;
7181   tree index, value;
7182
7183   if (TREE_CODE (constructor_type) != RECORD_TYPE
7184       && TREE_CODE (constructor_type) != ARRAY_TYPE)
7185     return;
7186
7187   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
7188     add_pending_init (index, value, NULL_TREE, false);
7189   constructor_elements = 0;
7190   if (TREE_CODE (constructor_type) == RECORD_TYPE)
7191     {
7192       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
7193       /* Skip any nameless bit fields at the beginning.  */
7194       while (constructor_unfilled_fields != 0
7195              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7196              && DECL_NAME (constructor_unfilled_fields) == 0)
7197         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
7198
7199     }
7200   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7201     {
7202       if (TYPE_DOMAIN (constructor_type))
7203         constructor_unfilled_index
7204             = convert (bitsizetype,
7205                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
7206       else
7207         constructor_unfilled_index = bitsize_zero_node;
7208     }
7209   constructor_incremental = 0;
7210 }
7211
7212 /* Build AVL tree from a string constant.  */
7213
7214 static void
7215 set_nonincremental_init_from_string (tree str)
7216 {
7217   tree value, purpose, type;
7218   HOST_WIDE_INT val[2];
7219   const char *p, *end;
7220   int byte, wchar_bytes, charwidth, bitpos;
7221
7222   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7223
7224   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7225   charwidth = TYPE_PRECISION (char_type_node);
7226   type = TREE_TYPE (constructor_type);
7227   p = TREE_STRING_POINTER (str);
7228   end = p + TREE_STRING_LENGTH (str);
7229
7230   for (purpose = bitsize_zero_node;
7231        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7232        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7233     {
7234       if (wchar_bytes == 1)
7235         {
7236           val[1] = (unsigned char) *p++;
7237           val[0] = 0;
7238         }
7239       else
7240         {
7241           val[0] = 0;
7242           val[1] = 0;
7243           for (byte = 0; byte < wchar_bytes; byte++)
7244             {
7245               if (BYTES_BIG_ENDIAN)
7246                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7247               else
7248                 bitpos = byte * charwidth;
7249               val[bitpos < HOST_BITS_PER_WIDE_INT]
7250                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7251                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7252             }
7253         }
7254
7255       if (!TYPE_UNSIGNED (type))
7256         {
7257           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7258           if (bitpos < HOST_BITS_PER_WIDE_INT)
7259             {
7260               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7261                 {
7262                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7263                   val[0] = -1;
7264                 }
7265             }
7266           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7267             {
7268               if (val[1] < 0)
7269                 val[0] = -1;
7270             }
7271           else if (val[0] & (((HOST_WIDE_INT) 1)
7272                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7273             val[0] |= ((HOST_WIDE_INT) -1)
7274                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7275         }
7276
7277       value = build_int_cst_wide (type, val[1], val[0]);
7278       add_pending_init (purpose, value, NULL_TREE, false);
7279     }
7280
7281   constructor_incremental = 0;
7282 }
7283
7284 /* Return value of FIELD in pending initializer or zero if the field was
7285    not initialized yet.  */
7286
7287 static tree
7288 find_init_member (tree field)
7289 {
7290   struct init_node *p;
7291
7292   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7293     {
7294       if (constructor_incremental
7295           && tree_int_cst_lt (field, constructor_unfilled_index))
7296         set_nonincremental_init ();
7297
7298       p = constructor_pending_elts;
7299       while (p)
7300         {
7301           if (tree_int_cst_lt (field, p->purpose))
7302             p = p->left;
7303           else if (tree_int_cst_lt (p->purpose, field))
7304             p = p->right;
7305           else
7306             return p->value;
7307         }
7308     }
7309   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7310     {
7311       tree bitpos = bit_position (field);
7312
7313       if (constructor_incremental
7314           && (!constructor_unfilled_fields
7315               || tree_int_cst_lt (bitpos,
7316                                   bit_position (constructor_unfilled_fields))))
7317         set_nonincremental_init ();
7318
7319       p = constructor_pending_elts;
7320       while (p)
7321         {
7322           if (field == p->purpose)
7323             return p->value;
7324           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7325             p = p->left;
7326           else
7327             p = p->right;
7328         }
7329     }
7330   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7331     {
7332       if (!VEC_empty (constructor_elt, constructor_elements)
7333           && (VEC_last (constructor_elt, constructor_elements)->index
7334               == field))
7335         return VEC_last (constructor_elt, constructor_elements)->value;
7336     }
7337   return 0;
7338 }
7339
7340 /* "Output" the next constructor element.
7341    At top level, really output it to assembler code now.
7342    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7343    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7344    TYPE is the data type that the containing data type wants here.
7345    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7346    If VALUE is a string constant, STRICT_STRING is true if it is
7347    unparenthesized or we should not warn here for it being parenthesized.
7348    For other types of VALUE, STRICT_STRING is not used.
7349
7350    PENDING if non-nil means output pending elements that belong
7351    right after this element.  (PENDING is normally 1;
7352    it is 0 while outputting pending elements, to avoid recursion.)
7353
7354    IMPLICIT is true if value comes from pop_init_level (1),
7355    the new initializer has been merged with the existing one
7356    and thus no warnings should be emitted about overriding an
7357    existing initializer.  */
7358
7359 static void
7360 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7361                      tree field, int pending, bool implicit)
7362 {
7363   tree semantic_type = NULL_TREE;
7364   constructor_elt *celt;
7365   bool maybe_const = true;
7366   bool npc;
7367
7368   if (type == error_mark_node || value == error_mark_node)
7369     {
7370       constructor_erroneous = 1;
7371       return;
7372     }
7373   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7374       && (TREE_CODE (value) == STRING_CST
7375           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7376       && !(TREE_CODE (value) == STRING_CST
7377            && TREE_CODE (type) == ARRAY_TYPE
7378            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7379       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7380                      TYPE_MAIN_VARIANT (type)))
7381     value = array_to_pointer_conversion (input_location, value);
7382
7383   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7384       && require_constant_value && !flag_isoc99 && pending)
7385     {
7386       /* As an extension, allow initializing objects with static storage
7387          duration with compound literals (which are then treated just as
7388          the brace enclosed list they contain).  */
7389       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7390       value = DECL_INITIAL (decl);
7391     }
7392
7393   npc = null_pointer_constant_p (value);
7394   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7395     {
7396       semantic_type = TREE_TYPE (value);
7397       value = TREE_OPERAND (value, 0);
7398     }
7399   value = c_fully_fold (value, require_constant_value, &maybe_const);
7400
7401   if (value == error_mark_node)
7402     constructor_erroneous = 1;
7403   else if (!TREE_CONSTANT (value))
7404     constructor_constant = 0;
7405   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7406            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7407                 || TREE_CODE (constructor_type) == UNION_TYPE)
7408                && DECL_C_BIT_FIELD (field)
7409                && TREE_CODE (value) != INTEGER_CST))
7410     constructor_simple = 0;
7411   if (!maybe_const)
7412     constructor_nonconst = 1;
7413
7414   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7415     {
7416       if (require_constant_value)
7417         {
7418           error_init ("initializer element is not constant");
7419           value = error_mark_node;
7420         }
7421       else if (require_constant_elements)
7422         pedwarn (input_location, 0,
7423                  "initializer element is not computable at load time");
7424     }
7425   else if (!maybe_const
7426            && (require_constant_value || require_constant_elements))
7427     pedwarn_init (input_location, 0,
7428                   "initializer element is not a constant expression");
7429
7430   /* Issue -Wc++-compat warnings about initializing a bitfield with
7431      enum type.  */
7432   if (warn_cxx_compat
7433       && field != NULL_TREE
7434       && TREE_CODE (field) == FIELD_DECL
7435       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7436       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7437           != TYPE_MAIN_VARIANT (type))
7438       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7439     {
7440       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7441       if (checktype != error_mark_node
7442           && (TYPE_MAIN_VARIANT (checktype)
7443               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7444         warning_init (OPT_Wc___compat,
7445                       "enum conversion in initialization is invalid in C++");
7446     }
7447
7448   /* If this field is empty (and not at the end of structure),
7449      don't do anything other than checking the initializer.  */
7450   if (field
7451       && (TREE_TYPE (field) == error_mark_node
7452           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7453               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7454               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7455                   || TREE_CHAIN (field)))))
7456     return;
7457
7458   if (semantic_type)
7459     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7460   value = digest_init (input_location, type, value, origtype, npc,
7461                        strict_string, require_constant_value);
7462   if (value == error_mark_node)
7463     {
7464       constructor_erroneous = 1;
7465       return;
7466     }
7467   if (require_constant_value || require_constant_elements)
7468     constant_expression_warning (value);
7469
7470   /* If this element doesn't come next in sequence,
7471      put it on constructor_pending_elts.  */
7472   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7473       && (!constructor_incremental
7474           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7475     {
7476       if (constructor_incremental
7477           && tree_int_cst_lt (field, constructor_unfilled_index))
7478         set_nonincremental_init ();
7479
7480       add_pending_init (field, value, origtype, implicit);
7481       return;
7482     }
7483   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7484            && (!constructor_incremental
7485                || field != constructor_unfilled_fields))
7486     {
7487       /* We do this for records but not for unions.  In a union,
7488          no matter which field is specified, it can be initialized
7489          right away since it starts at the beginning of the union.  */
7490       if (constructor_incremental)
7491         {
7492           if (!constructor_unfilled_fields)
7493             set_nonincremental_init ();
7494           else
7495             {
7496               tree bitpos, unfillpos;
7497
7498               bitpos = bit_position (field);
7499               unfillpos = bit_position (constructor_unfilled_fields);
7500
7501               if (tree_int_cst_lt (bitpos, unfillpos))
7502                 set_nonincremental_init ();
7503             }
7504         }
7505
7506       add_pending_init (field, value, origtype, implicit);
7507       return;
7508     }
7509   else if (TREE_CODE (constructor_type) == UNION_TYPE
7510            && !VEC_empty (constructor_elt, constructor_elements))
7511     {
7512       if (!implicit)
7513         {
7514           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7515                                            constructor_elements)->value))
7516             warning_init (0,
7517                           "initialized field with side-effects overwritten");
7518           else if (warn_override_init)
7519             warning_init (OPT_Woverride_init, "initialized field overwritten");
7520         }
7521
7522       /* We can have just one union field set.  */
7523       constructor_elements = 0;
7524     }
7525
7526   /* Otherwise, output this element either to
7527      constructor_elements or to the assembler file.  */
7528
7529   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7530   celt->index = field;
7531   celt->value = value;
7532
7533   /* Advance the variable that indicates sequential elements output.  */
7534   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7535     constructor_unfilled_index
7536       = size_binop_loc (input_location, PLUS_EXPR, constructor_unfilled_index,
7537                         bitsize_one_node);
7538   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7539     {
7540       constructor_unfilled_fields
7541         = TREE_CHAIN (constructor_unfilled_fields);
7542
7543       /* Skip any nameless bit fields.  */
7544       while (constructor_unfilled_fields != 0
7545              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7546              && DECL_NAME (constructor_unfilled_fields) == 0)
7547         constructor_unfilled_fields =
7548           TREE_CHAIN (constructor_unfilled_fields);
7549     }
7550   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7551     constructor_unfilled_fields = 0;
7552
7553   /* Now output any pending elements which have become next.  */
7554   if (pending)
7555     output_pending_init_elements (0);
7556 }
7557
7558 /* Output any pending elements which have become next.
7559    As we output elements, constructor_unfilled_{fields,index}
7560    advances, which may cause other elements to become next;
7561    if so, they too are output.
7562
7563    If ALL is 0, we return when there are
7564    no more pending elements to output now.
7565
7566    If ALL is 1, we output space as necessary so that
7567    we can output all the pending elements.  */
7568
7569 static void
7570 output_pending_init_elements (int all)
7571 {
7572   struct init_node *elt = constructor_pending_elts;
7573   tree next;
7574
7575  retry:
7576
7577   /* Look through the whole pending tree.
7578      If we find an element that should be output now,
7579      output it.  Otherwise, set NEXT to the element
7580      that comes first among those still pending.  */
7581
7582   next = 0;
7583   while (elt)
7584     {
7585       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7586         {
7587           if (tree_int_cst_equal (elt->purpose,
7588                                   constructor_unfilled_index))
7589             output_init_element (elt->value, elt->origtype, true,
7590                                  TREE_TYPE (constructor_type),
7591                                  constructor_unfilled_index, 0, false);
7592           else if (tree_int_cst_lt (constructor_unfilled_index,
7593                                     elt->purpose))
7594             {
7595               /* Advance to the next smaller node.  */
7596               if (elt->left)
7597                 elt = elt->left;
7598               else
7599                 {
7600                   /* We have reached the smallest node bigger than the
7601                      current unfilled index.  Fill the space first.  */
7602                   next = elt->purpose;
7603                   break;
7604                 }
7605             }
7606           else
7607             {
7608               /* Advance to the next bigger node.  */
7609               if (elt->right)
7610                 elt = elt->right;
7611               else
7612                 {
7613                   /* We have reached the biggest node in a subtree.  Find
7614                      the parent of it, which is the next bigger node.  */
7615                   while (elt->parent && elt->parent->right == elt)
7616                     elt = elt->parent;
7617                   elt = elt->parent;
7618                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7619                                               elt->purpose))
7620                     {
7621                       next = elt->purpose;
7622                       break;
7623                     }
7624                 }
7625             }
7626         }
7627       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7628                || TREE_CODE (constructor_type) == UNION_TYPE)
7629         {
7630           tree ctor_unfilled_bitpos, elt_bitpos;
7631
7632           /* If the current record is complete we are done.  */
7633           if (constructor_unfilled_fields == 0)
7634             break;
7635
7636           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7637           elt_bitpos = bit_position (elt->purpose);
7638           /* We can't compare fields here because there might be empty
7639              fields in between.  */
7640           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7641             {
7642               constructor_unfilled_fields = elt->purpose;
7643               output_init_element (elt->value, elt->origtype, true,
7644                                    TREE_TYPE (elt->purpose),
7645                                    elt->purpose, 0, false);
7646             }
7647           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7648             {
7649               /* Advance to the next smaller node.  */
7650               if (elt->left)
7651                 elt = elt->left;
7652               else
7653                 {
7654                   /* We have reached the smallest node bigger than the
7655                      current unfilled field.  Fill the space first.  */
7656                   next = elt->purpose;
7657                   break;
7658                 }
7659             }
7660           else
7661             {
7662               /* Advance to the next bigger node.  */
7663               if (elt->right)
7664                 elt = elt->right;
7665               else
7666                 {
7667                   /* We have reached the biggest node in a subtree.  Find
7668                      the parent of it, which is the next bigger node.  */
7669                   while (elt->parent && elt->parent->right == elt)
7670                     elt = elt->parent;
7671                   elt = elt->parent;
7672                   if (elt
7673                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7674                                            bit_position (elt->purpose))))
7675                     {
7676                       next = elt->purpose;
7677                       break;
7678                     }
7679                 }
7680             }
7681         }
7682     }
7683
7684   /* Ordinarily return, but not if we want to output all
7685      and there are elements left.  */
7686   if (!(all && next != 0))
7687     return;
7688
7689   /* If it's not incremental, just skip over the gap, so that after
7690      jumping to retry we will output the next successive element.  */
7691   if (TREE_CODE (constructor_type) == RECORD_TYPE
7692       || TREE_CODE (constructor_type) == UNION_TYPE)
7693     constructor_unfilled_fields = next;
7694   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7695     constructor_unfilled_index = next;
7696
7697   /* ELT now points to the node in the pending tree with the next
7698      initializer to output.  */
7699   goto retry;
7700 }
7701 \f
7702 /* Add one non-braced element to the current constructor level.
7703    This adjusts the current position within the constructor's type.
7704    This may also start or terminate implicit levels
7705    to handle a partly-braced initializer.
7706
7707    Once this has found the correct level for the new element,
7708    it calls output_init_element.
7709
7710    IMPLICIT is true if value comes from pop_init_level (1),
7711    the new initializer has been merged with the existing one
7712    and thus no warnings should be emitted about overriding an
7713    existing initializer.  */
7714
7715 void
7716 process_init_element (struct c_expr value, bool implicit)
7717 {
7718   tree orig_value = value.value;
7719   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7720   bool strict_string = value.original_code == STRING_CST;
7721
7722   designator_depth = 0;
7723   designator_erroneous = 0;
7724
7725   /* Handle superfluous braces around string cst as in
7726      char x[] = {"foo"}; */
7727   if (string_flag
7728       && constructor_type
7729       && TREE_CODE (constructor_type) == ARRAY_TYPE
7730       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7731       && integer_zerop (constructor_unfilled_index))
7732     {
7733       if (constructor_stack->replacement_value.value)
7734         error_init ("excess elements in char array initializer");
7735       constructor_stack->replacement_value = value;
7736       return;
7737     }
7738
7739   if (constructor_stack->replacement_value.value != 0)
7740     {
7741       error_init ("excess elements in struct initializer");
7742       return;
7743     }
7744
7745   /* Ignore elements of a brace group if it is entirely superfluous
7746      and has already been diagnosed.  */
7747   if (constructor_type == 0)
7748     return;
7749
7750   /* If we've exhausted any levels that didn't have braces,
7751      pop them now.  */
7752   while (constructor_stack->implicit)
7753     {
7754       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7755            || TREE_CODE (constructor_type) == UNION_TYPE)
7756           && constructor_fields == 0)
7757         process_init_element (pop_init_level (1), true);
7758       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
7759                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
7760                && (constructor_max_index == 0
7761                    || tree_int_cst_lt (constructor_max_index,
7762                                        constructor_index)))
7763         process_init_element (pop_init_level (1), true);
7764       else
7765         break;
7766     }
7767
7768   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7769   if (constructor_range_stack)
7770     {
7771       /* If value is a compound literal and we'll be just using its
7772          content, don't put it into a SAVE_EXPR.  */
7773       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7774           || !require_constant_value
7775           || flag_isoc99)
7776         {
7777           tree semantic_type = NULL_TREE;
7778           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7779             {
7780               semantic_type = TREE_TYPE (value.value);
7781               value.value = TREE_OPERAND (value.value, 0);
7782             }
7783           value.value = c_save_expr (value.value);
7784           if (semantic_type)
7785             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7786                                   value.value);
7787         }
7788     }
7789
7790   while (1)
7791     {
7792       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7793         {
7794           tree fieldtype;
7795           enum tree_code fieldcode;
7796
7797           if (constructor_fields == 0)
7798             {
7799               pedwarn_init (input_location, 0,
7800                             "excess elements in struct initializer");
7801               break;
7802             }
7803
7804           fieldtype = TREE_TYPE (constructor_fields);
7805           if (fieldtype != error_mark_node)
7806             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7807           fieldcode = TREE_CODE (fieldtype);
7808
7809           /* Error for non-static initialization of a flexible array member.  */
7810           if (fieldcode == ARRAY_TYPE
7811               && !require_constant_value
7812               && TYPE_SIZE (fieldtype) == NULL_TREE
7813               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7814             {
7815               error_init ("non-static initialization of a flexible array member");
7816               break;
7817             }
7818
7819           /* Accept a string constant to initialize a subarray.  */
7820           if (value.value != 0
7821               && fieldcode == ARRAY_TYPE
7822               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7823               && string_flag)
7824             value.value = orig_value;
7825           /* Otherwise, if we have come to a subaggregate,
7826              and we don't have an element of its type, push into it.  */
7827           else if (value.value != 0
7828                    && value.value != error_mark_node
7829                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7830                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7831                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7832             {
7833               push_init_level (1);
7834               continue;
7835             }
7836
7837           if (value.value)
7838             {
7839               push_member_name (constructor_fields);
7840               output_init_element (value.value, value.original_type,
7841                                    strict_string, fieldtype,
7842                                    constructor_fields, 1, implicit);
7843               RESTORE_SPELLING_DEPTH (constructor_depth);
7844             }
7845           else
7846             /* Do the bookkeeping for an element that was
7847                directly output as a constructor.  */
7848             {
7849               /* For a record, keep track of end position of last field.  */
7850               if (DECL_SIZE (constructor_fields))
7851                 constructor_bit_index
7852                   = size_binop_loc (input_location, PLUS_EXPR,
7853                                     bit_position (constructor_fields),
7854                                     DECL_SIZE (constructor_fields));
7855
7856               /* If the current field was the first one not yet written out,
7857                  it isn't now, so update.  */
7858               if (constructor_unfilled_fields == constructor_fields)
7859                 {
7860                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7861                   /* Skip any nameless bit fields.  */
7862                   while (constructor_unfilled_fields != 0
7863                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7864                          && DECL_NAME (constructor_unfilled_fields) == 0)
7865                     constructor_unfilled_fields =
7866                       TREE_CHAIN (constructor_unfilled_fields);
7867                 }
7868             }
7869
7870           constructor_fields = TREE_CHAIN (constructor_fields);
7871           /* Skip any nameless bit fields at the beginning.  */
7872           while (constructor_fields != 0
7873                  && DECL_C_BIT_FIELD (constructor_fields)
7874                  && DECL_NAME (constructor_fields) == 0)
7875             constructor_fields = TREE_CHAIN (constructor_fields);
7876         }
7877       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7878         {
7879           tree fieldtype;
7880           enum tree_code fieldcode;
7881
7882           if (constructor_fields == 0)
7883             {
7884               pedwarn_init (input_location, 0,
7885                             "excess elements in union initializer");
7886               break;
7887             }
7888
7889           fieldtype = TREE_TYPE (constructor_fields);
7890           if (fieldtype != error_mark_node)
7891             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7892           fieldcode = TREE_CODE (fieldtype);
7893
7894           /* Warn that traditional C rejects initialization of unions.
7895              We skip the warning if the value is zero.  This is done
7896              under the assumption that the zero initializer in user
7897              code appears conditioned on e.g. __STDC__ to avoid
7898              "missing initializer" warnings and relies on default
7899              initialization to zero in the traditional C case.
7900              We also skip the warning if the initializer is designated,
7901              again on the assumption that this must be conditional on
7902              __STDC__ anyway (and we've already complained about the
7903              member-designator already).  */
7904           if (!in_system_header && !constructor_designated
7905               && !(value.value && (integer_zerop (value.value)
7906                                    || real_zerop (value.value))))
7907             warning (OPT_Wtraditional, "traditional C rejects initialization "
7908                      "of unions");
7909
7910           /* Accept a string constant to initialize a subarray.  */
7911           if (value.value != 0
7912               && fieldcode == ARRAY_TYPE
7913               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7914               && string_flag)
7915             value.value = orig_value;
7916           /* Otherwise, if we have come to a subaggregate,
7917              and we don't have an element of its type, push into it.  */
7918           else if (value.value != 0
7919                    && value.value != error_mark_node
7920                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7921                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7922                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7923             {
7924               push_init_level (1);
7925               continue;
7926             }
7927
7928           if (value.value)
7929             {
7930               push_member_name (constructor_fields);
7931               output_init_element (value.value, value.original_type,
7932                                    strict_string, fieldtype,
7933                                    constructor_fields, 1, implicit);
7934               RESTORE_SPELLING_DEPTH (constructor_depth);
7935             }
7936           else
7937             /* Do the bookkeeping for an element that was
7938                directly output as a constructor.  */
7939             {
7940               constructor_bit_index = DECL_SIZE (constructor_fields);
7941               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7942             }
7943
7944           constructor_fields = 0;
7945         }
7946       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7947         {
7948           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7949           enum tree_code eltcode = TREE_CODE (elttype);
7950
7951           /* Accept a string constant to initialize a subarray.  */
7952           if (value.value != 0
7953               && eltcode == ARRAY_TYPE
7954               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7955               && string_flag)
7956             value.value = orig_value;
7957           /* Otherwise, if we have come to a subaggregate,
7958              and we don't have an element of its type, push into it.  */
7959           else if (value.value != 0
7960                    && value.value != error_mark_node
7961                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7962                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7963                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
7964             {
7965               push_init_level (1);
7966               continue;
7967             }
7968
7969           if (constructor_max_index != 0
7970               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7971                   || integer_all_onesp (constructor_max_index)))
7972             {
7973               pedwarn_init (input_location, 0,
7974                             "excess elements in array initializer");
7975               break;
7976             }
7977
7978           /* Now output the actual element.  */
7979           if (value.value)
7980             {
7981               push_array_bounds (tree_low_cst (constructor_index, 1));
7982               output_init_element (value.value, value.original_type,
7983                                    strict_string, elttype,
7984                                    constructor_index, 1, implicit);
7985               RESTORE_SPELLING_DEPTH (constructor_depth);
7986             }
7987
7988           constructor_index
7989             = size_binop_loc (input_location, PLUS_EXPR,
7990                               constructor_index, bitsize_one_node);
7991
7992           if (!value.value)
7993             /* If we are doing the bookkeeping for an element that was
7994                directly output as a constructor, we must update
7995                constructor_unfilled_index.  */
7996             constructor_unfilled_index = constructor_index;
7997         }
7998       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7999         {
8000           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
8001
8002          /* Do a basic check of initializer size.  Note that vectors
8003             always have a fixed size derived from their type.  */
8004           if (tree_int_cst_lt (constructor_max_index, constructor_index))
8005             {
8006               pedwarn_init (input_location, 0,
8007                             "excess elements in vector initializer");
8008               break;
8009             }
8010
8011           /* Now output the actual element.  */
8012           if (value.value)
8013             {
8014               if (TREE_CODE (value.value) == VECTOR_CST)
8015                 elttype = TYPE_MAIN_VARIANT (constructor_type);
8016               output_init_element (value.value, value.original_type,
8017                                    strict_string, elttype,
8018                                    constructor_index, 1, implicit);
8019             }
8020
8021           constructor_index
8022             = size_binop_loc (input_location,
8023                               PLUS_EXPR, constructor_index, bitsize_one_node);
8024
8025           if (!value.value)
8026             /* If we are doing the bookkeeping for an element that was
8027                directly output as a constructor, we must update
8028                constructor_unfilled_index.  */
8029             constructor_unfilled_index = constructor_index;
8030         }
8031
8032       /* Handle the sole element allowed in a braced initializer
8033          for a scalar variable.  */
8034       else if (constructor_type != error_mark_node
8035                && constructor_fields == 0)
8036         {
8037           pedwarn_init (input_location, 0,
8038                         "excess elements in scalar initializer");
8039           break;
8040         }
8041       else
8042         {
8043           if (value.value)
8044             output_init_element (value.value, value.original_type,
8045                                  strict_string, constructor_type,
8046                                  NULL_TREE, 1, implicit);
8047           constructor_fields = 0;
8048         }
8049
8050       /* Handle range initializers either at this level or anywhere higher
8051          in the designator stack.  */
8052       if (constructor_range_stack)
8053         {
8054           struct constructor_range_stack *p, *range_stack;
8055           int finish = 0;
8056
8057           range_stack = constructor_range_stack;
8058           constructor_range_stack = 0;
8059           while (constructor_stack != range_stack->stack)
8060             {
8061               gcc_assert (constructor_stack->implicit);
8062               process_init_element (pop_init_level (1), true);
8063             }
8064           for (p = range_stack;
8065                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
8066                p = p->prev)
8067             {
8068               gcc_assert (constructor_stack->implicit);
8069               process_init_element (pop_init_level (1), true);
8070             }
8071
8072           p->index = size_binop_loc (input_location,
8073                                      PLUS_EXPR, p->index, bitsize_one_node);
8074           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
8075             finish = 1;
8076
8077           while (1)
8078             {
8079               constructor_index = p->index;
8080               constructor_fields = p->fields;
8081               if (finish && p->range_end && p->index == p->range_start)
8082                 {
8083                   finish = 0;
8084                   p->prev = 0;
8085                 }
8086               p = p->next;
8087               if (!p)
8088                 break;
8089               push_init_level (2);
8090               p->stack = constructor_stack;
8091               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
8092                 p->index = p->range_start;
8093             }
8094
8095           if (!finish)
8096             constructor_range_stack = range_stack;
8097           continue;
8098         }
8099
8100       break;
8101     }
8102
8103   constructor_range_stack = 0;
8104 }
8105 \f
8106 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
8107    (guaranteed to be 'volatile' or null) and ARGS (represented using
8108    an ASM_EXPR node).  */
8109 tree
8110 build_asm_stmt (tree cv_qualifier, tree args)
8111 {
8112   if (!ASM_VOLATILE_P (args) && cv_qualifier)
8113     ASM_VOLATILE_P (args) = 1;
8114   return add_stmt (args);
8115 }
8116
8117 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
8118    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
8119    SIMPLE indicates whether there was anything at all after the
8120    string in the asm expression -- asm("blah") and asm("blah" : )
8121    are subtly different.  We use a ASM_EXPR node to represent this.  */
8122 tree
8123 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
8124                 tree clobbers, tree labels, bool simple)
8125 {
8126   tree tail;
8127   tree args;
8128   int i;
8129   const char *constraint;
8130   const char **oconstraints;
8131   bool allows_mem, allows_reg, is_inout;
8132   int ninputs, noutputs;
8133
8134   ninputs = list_length (inputs);
8135   noutputs = list_length (outputs);
8136   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
8137
8138   string = resolve_asm_operand_names (string, outputs, inputs, labels);
8139
8140   /* Remove output conversions that change the type but not the mode.  */
8141   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
8142     {
8143       tree output = TREE_VALUE (tail);
8144
8145       /* ??? Really, this should not be here.  Users should be using a
8146          proper lvalue, dammit.  But there's a long history of using casts
8147          in the output operands.  In cases like longlong.h, this becomes a
8148          primitive form of typechecking -- if the cast can be removed, then
8149          the output operand had a type of the proper width; otherwise we'll
8150          get an error.  Gross, but ...  */
8151       STRIP_NOPS (output);
8152
8153       if (!lvalue_or_else (output, lv_asm))
8154         output = error_mark_node;
8155
8156       if (output != error_mark_node
8157           && (TREE_READONLY (output)
8158               || TYPE_READONLY (TREE_TYPE (output))
8159               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
8160                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
8161                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
8162         readonly_error (output, lv_asm);
8163
8164       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8165       oconstraints[i] = constraint;
8166
8167       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
8168                                    &allows_mem, &allows_reg, &is_inout))
8169         {
8170           /* If the operand is going to end up in memory,
8171              mark it addressable.  */
8172           if (!allows_reg && !c_mark_addressable (output))
8173             output = error_mark_node;
8174         }
8175       else
8176         output = error_mark_node;
8177
8178       TREE_VALUE (tail) = output;
8179     }
8180
8181   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
8182     {
8183       tree input;
8184
8185       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8186       input = TREE_VALUE (tail);
8187
8188       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
8189                                   oconstraints, &allows_mem, &allows_reg))
8190         {
8191           /* If the operand is going to end up in memory,
8192              mark it addressable.  */
8193           if (!allows_reg && allows_mem)
8194             {
8195               /* Strip the nops as we allow this case.  FIXME, this really
8196                  should be rejected or made deprecated.  */
8197               STRIP_NOPS (input);
8198               if (!c_mark_addressable (input))
8199                 input = error_mark_node;
8200           }
8201         }
8202       else
8203         input = error_mark_node;
8204
8205       TREE_VALUE (tail) = input;
8206     }
8207
8208   /* ASMs with labels cannot have outputs.  This should have been
8209      enforced by the parser.  */
8210   gcc_assert (outputs == NULL || labels == NULL);
8211
8212   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers, labels);
8213
8214   /* asm statements without outputs, including simple ones, are treated
8215      as volatile.  */
8216   ASM_INPUT_P (args) = simple;
8217   ASM_VOLATILE_P (args) = (noutputs == 0);
8218
8219   return args;
8220 }
8221 \f
8222 /* Generate a goto statement to LABEL.  LOC is the location of the
8223    GOTO.  */
8224
8225 tree
8226 c_finish_goto_label (location_t loc, tree label)
8227 {
8228   tree decl = lookup_label_for_goto (loc, label);
8229   if (!decl)
8230     return NULL_TREE;
8231   TREE_USED (decl) = 1;
8232   {
8233     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8234     SET_EXPR_LOCATION (t, loc);
8235     return add_stmt (t);
8236   }
8237 }
8238
8239 /* Generate a computed goto statement to EXPR.  LOC is the location of
8240    the GOTO.  */
8241
8242 tree
8243 c_finish_goto_ptr (location_t loc, tree expr)
8244 {
8245   tree t;
8246   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8247   expr = c_fully_fold (expr, false, NULL);
8248   expr = convert (ptr_type_node, expr);
8249   t = build1 (GOTO_EXPR, void_type_node, expr);
8250   SET_EXPR_LOCATION (t, loc);
8251   return add_stmt (t);
8252 }
8253
8254 /* Generate a C `return' statement.  RETVAL is the expression for what
8255    to return, or a null pointer for `return;' with no value.  LOC is
8256    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8257    is the original type of RETVAL.  */
8258
8259 tree
8260 c_finish_return (location_t loc, tree retval, tree origtype)
8261 {
8262   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8263   bool no_warning = false;
8264   bool npc = false;
8265
8266   if (TREE_THIS_VOLATILE (current_function_decl))
8267     warning_at (loc, 0,
8268                 "function declared %<noreturn%> has a %<return%> statement");
8269
8270   if (retval)
8271     {
8272       tree semantic_type = NULL_TREE;
8273       npc = null_pointer_constant_p (retval);
8274       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8275         {
8276           semantic_type = TREE_TYPE (retval);
8277           retval = TREE_OPERAND (retval, 0);
8278         }
8279       retval = c_fully_fold (retval, false, NULL);
8280       if (semantic_type)
8281         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8282     }
8283
8284   if (!retval)
8285     {
8286       current_function_returns_null = 1;
8287       if ((warn_return_type || flag_isoc99)
8288           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8289         {
8290           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8291                        "%<return%> with no value, in "
8292                        "function returning non-void");
8293           no_warning = true;
8294         }
8295     }
8296   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8297     {
8298       current_function_returns_null = 1;
8299       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8300         pedwarn (loc, 0,
8301                  "%<return%> with a value, in function returning void");
8302       else
8303         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8304                  "%<return%> with expression, in function returning void");
8305     }
8306   else
8307     {
8308       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8309                                        ic_return,
8310                                        npc, NULL_TREE, NULL_TREE, 0);
8311       tree res = DECL_RESULT (current_function_decl);
8312       tree inner;
8313
8314       current_function_returns_value = 1;
8315       if (t == error_mark_node)
8316         return NULL_TREE;
8317
8318       inner = t = convert (TREE_TYPE (res), t);
8319
8320       /* Strip any conversions, additions, and subtractions, and see if
8321          we are returning the address of a local variable.  Warn if so.  */
8322       while (1)
8323         {
8324           switch (TREE_CODE (inner))
8325             {
8326             CASE_CONVERT:
8327             case NON_LVALUE_EXPR:
8328             case PLUS_EXPR:
8329             case POINTER_PLUS_EXPR:
8330               inner = TREE_OPERAND (inner, 0);
8331               continue;
8332
8333             case MINUS_EXPR:
8334               /* If the second operand of the MINUS_EXPR has a pointer
8335                  type (or is converted from it), this may be valid, so
8336                  don't give a warning.  */
8337               {
8338                 tree op1 = TREE_OPERAND (inner, 1);
8339
8340                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8341                        && (CONVERT_EXPR_P (op1)
8342                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8343                   op1 = TREE_OPERAND (op1, 0);
8344
8345                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8346                   break;
8347
8348                 inner = TREE_OPERAND (inner, 0);
8349                 continue;
8350               }
8351
8352             case ADDR_EXPR:
8353               inner = TREE_OPERAND (inner, 0);
8354
8355               while (REFERENCE_CLASS_P (inner)
8356                      && TREE_CODE (inner) != INDIRECT_REF)
8357                 inner = TREE_OPERAND (inner, 0);
8358
8359               if (DECL_P (inner)
8360                   && !DECL_EXTERNAL (inner)
8361                   && !TREE_STATIC (inner)
8362                   && DECL_CONTEXT (inner) == current_function_decl)
8363                 warning_at (loc,
8364                             0, "function returns address of local variable");
8365               break;
8366
8367             default:
8368               break;
8369             }
8370
8371           break;
8372         }
8373
8374       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8375       SET_EXPR_LOCATION (retval, loc);
8376
8377       if (warn_sequence_point)
8378         verify_sequence_points (retval);
8379     }
8380
8381   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8382   TREE_NO_WARNING (ret_stmt) |= no_warning;
8383   return add_stmt (ret_stmt);
8384 }
8385 \f
8386 struct c_switch {
8387   /* The SWITCH_EXPR being built.  */
8388   tree switch_expr;
8389
8390   /* The original type of the testing expression, i.e. before the
8391      default conversion is applied.  */
8392   tree orig_type;
8393
8394   /* A splay-tree mapping the low element of a case range to the high
8395      element, or NULL_TREE if there is no high element.  Used to
8396      determine whether or not a new case label duplicates an old case
8397      label.  We need a tree, rather than simply a hash table, because
8398      of the GNU case range extension.  */
8399   splay_tree cases;
8400
8401   /* The bindings at the point of the switch.  This is used for
8402      warnings crossing decls when branching to a case label.  */
8403   struct c_spot_bindings *bindings;
8404
8405   /* The next node on the stack.  */
8406   struct c_switch *next;
8407 };
8408
8409 /* A stack of the currently active switch statements.  The innermost
8410    switch statement is on the top of the stack.  There is no need to
8411    mark the stack for garbage collection because it is only active
8412    during the processing of the body of a function, and we never
8413    collect at that point.  */
8414
8415 struct c_switch *c_switch_stack;
8416
8417 /* Start a C switch statement, testing expression EXP.  Return the new
8418    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8419    SWITCH_COND_LOC is the location of the switch's condition.  */
8420
8421 tree
8422 c_start_case (location_t switch_loc,
8423               location_t switch_cond_loc,
8424               tree exp)
8425 {
8426   tree orig_type = error_mark_node;
8427   struct c_switch *cs;
8428
8429   if (exp != error_mark_node)
8430     {
8431       orig_type = TREE_TYPE (exp);
8432
8433       if (!INTEGRAL_TYPE_P (orig_type))
8434         {
8435           if (orig_type != error_mark_node)
8436             {
8437               error_at (switch_cond_loc, "switch quantity not an integer");
8438               orig_type = error_mark_node;
8439             }
8440           exp = integer_zero_node;
8441         }
8442       else
8443         {
8444           tree type = TYPE_MAIN_VARIANT (orig_type);
8445
8446           if (!in_system_header
8447               && (type == long_integer_type_node
8448                   || type == long_unsigned_type_node))
8449             warning_at (switch_cond_loc,
8450                         OPT_Wtraditional, "%<long%> switch expression not "
8451                         "converted to %<int%> in ISO C");
8452
8453           exp = c_fully_fold (exp, false, NULL);
8454           exp = default_conversion (exp);
8455
8456           if (warn_sequence_point)
8457             verify_sequence_points (exp);
8458         }
8459     }
8460
8461   /* Add this new SWITCH_EXPR to the stack.  */
8462   cs = XNEW (struct c_switch);
8463   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8464   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8465   cs->orig_type = orig_type;
8466   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8467   cs->bindings = c_get_switch_bindings ();
8468   cs->next = c_switch_stack;
8469   c_switch_stack = cs;
8470
8471   return add_stmt (cs->switch_expr);
8472 }
8473
8474 /* Process a case label at location LOC.  */
8475
8476 tree
8477 do_case (location_t loc, tree low_value, tree high_value)
8478 {
8479   tree label = NULL_TREE;
8480
8481   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8482     {
8483       low_value = c_fully_fold (low_value, false, NULL);
8484       if (TREE_CODE (low_value) == INTEGER_CST)
8485         pedwarn (input_location, OPT_pedantic,
8486                  "case label is not an integer constant expression");
8487     }
8488
8489   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8490     {
8491       high_value = c_fully_fold (high_value, false, NULL);
8492       if (TREE_CODE (high_value) == INTEGER_CST)
8493         pedwarn (input_location, OPT_pedantic,
8494                  "case label is not an integer constant expression");
8495     }
8496
8497   if (c_switch_stack == NULL)
8498     {
8499       if (low_value)
8500         error_at (loc, "case label not within a switch statement");
8501       else
8502         error_at (loc, "%<default%> label not within a switch statement");
8503       return NULL_TREE;
8504     }
8505
8506   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8507                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8508                                     loc))
8509     return NULL_TREE;
8510
8511   label = c_add_case_label (loc, c_switch_stack->cases,
8512                             SWITCH_COND (c_switch_stack->switch_expr),
8513                             c_switch_stack->orig_type,
8514                             low_value, high_value);
8515   if (label == error_mark_node)
8516     label = NULL_TREE;
8517   return label;
8518 }
8519
8520 /* Finish the switch statement.  */
8521
8522 void
8523 c_finish_case (tree body)
8524 {
8525   struct c_switch *cs = c_switch_stack;
8526   location_t switch_location;
8527
8528   SWITCH_BODY (cs->switch_expr) = body;
8529
8530   /* Emit warnings as needed.  */
8531   switch_location = EXPR_LOCATION (cs->switch_expr);
8532   c_do_switch_warnings (cs->cases, switch_location,
8533                         TREE_TYPE (cs->switch_expr),
8534                         SWITCH_COND (cs->switch_expr));
8535
8536   /* Pop the stack.  */
8537   c_switch_stack = cs->next;
8538   splay_tree_delete (cs->cases);
8539   c_release_switch_bindings (cs->bindings);
8540   XDELETE (cs);
8541 }
8542 \f
8543 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8544    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8545    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8546    statement, and was not surrounded with parenthesis.  */
8547
8548 void
8549 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8550                   tree else_block, bool nested_if)
8551 {
8552   tree stmt;
8553
8554   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8555   if (warn_parentheses && nested_if && else_block == NULL)
8556     {
8557       tree inner_if = then_block;
8558
8559       /* We know from the grammar productions that there is an IF nested
8560          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8561          it might not be exactly THEN_BLOCK, but should be the last
8562          non-container statement within.  */
8563       while (1)
8564         switch (TREE_CODE (inner_if))
8565           {
8566           case COND_EXPR:
8567             goto found;
8568           case BIND_EXPR:
8569             inner_if = BIND_EXPR_BODY (inner_if);
8570             break;
8571           case STATEMENT_LIST:
8572             inner_if = expr_last (then_block);
8573             break;
8574           case TRY_FINALLY_EXPR:
8575           case TRY_CATCH_EXPR:
8576             inner_if = TREE_OPERAND (inner_if, 0);
8577             break;
8578           default:
8579             gcc_unreachable ();
8580           }
8581     found:
8582
8583       if (COND_EXPR_ELSE (inner_if))
8584          warning_at (if_locus, OPT_Wparentheses,
8585                      "suggest explicit braces to avoid ambiguous %<else%>");
8586     }
8587
8588   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8589   SET_EXPR_LOCATION (stmt, if_locus);
8590   add_stmt (stmt);
8591 }
8592
8593 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8594    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8595    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8596    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8597    the continue label.  Everything is allowed to be NULL.  */
8598
8599 void
8600 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8601                tree blab, tree clab, bool cond_is_first)
8602 {
8603   tree entry = NULL, exit = NULL, t;
8604
8605   /* If the condition is zero don't generate a loop construct.  */
8606   if (cond && integer_zerop (cond))
8607     {
8608       if (cond_is_first)
8609         {
8610           t = build_and_jump (&blab);
8611           SET_EXPR_LOCATION (t, start_locus);
8612           add_stmt (t);
8613         }
8614     }
8615   else
8616     {
8617       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8618
8619       /* If we have an exit condition, then we build an IF with gotos either
8620          out of the loop, or to the top of it.  If there's no exit condition,
8621          then we just build a jump back to the top.  */
8622       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8623
8624       if (cond && !integer_nonzerop (cond))
8625         {
8626           /* Canonicalize the loop condition to the end.  This means
8627              generating a branch to the loop condition.  Reuse the
8628              continue label, if possible.  */
8629           if (cond_is_first)
8630             {
8631               if (incr || !clab)
8632                 {
8633                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8634                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8635                 }
8636               else
8637                 t = build1 (GOTO_EXPR, void_type_node, clab);
8638               SET_EXPR_LOCATION (t, start_locus);
8639               add_stmt (t);
8640             }
8641
8642           t = build_and_jump (&blab);
8643           if (cond_is_first)
8644             exit = fold_build3_loc (start_locus,
8645                                 COND_EXPR, void_type_node, cond, exit, t);
8646           else
8647             exit = fold_build3_loc (input_location,
8648                                 COND_EXPR, void_type_node, cond, exit, t);
8649         }
8650
8651       add_stmt (top);
8652     }
8653
8654   if (body)
8655     add_stmt (body);
8656   if (clab)
8657     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8658   if (incr)
8659     add_stmt (incr);
8660   if (entry)
8661     add_stmt (entry);
8662   if (exit)
8663     add_stmt (exit);
8664   if (blab)
8665     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8666 }
8667
8668 tree
8669 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
8670 {
8671   bool skip;
8672   tree label = *label_p;
8673
8674   /* In switch statements break is sometimes stylistically used after
8675      a return statement.  This can lead to spurious warnings about
8676      control reaching the end of a non-void function when it is
8677      inlined.  Note that we are calling block_may_fallthru with
8678      language specific tree nodes; this works because
8679      block_may_fallthru returns true when given something it does not
8680      understand.  */
8681   skip = !block_may_fallthru (cur_stmt_list);
8682
8683   if (!label)
8684     {
8685       if (!skip)
8686         *label_p = label = create_artificial_label (loc);
8687     }
8688   else if (TREE_CODE (label) == LABEL_DECL)
8689     ;
8690   else switch (TREE_INT_CST_LOW (label))
8691     {
8692     case 0:
8693       if (is_break)
8694         error_at (loc, "break statement not within loop or switch");
8695       else
8696         error_at (loc, "continue statement not within a loop");
8697       return NULL_TREE;
8698
8699     case 1:
8700       gcc_assert (is_break);
8701       error_at (loc, "break statement used with OpenMP for loop");
8702       return NULL_TREE;
8703
8704     default:
8705       gcc_unreachable ();
8706     }
8707
8708   if (skip)
8709     return NULL_TREE;
8710
8711   if (!is_break)
8712     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8713
8714   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8715 }
8716
8717 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8718
8719 static void
8720 emit_side_effect_warnings (location_t loc, tree expr)
8721 {
8722   if (expr == error_mark_node)
8723     ;
8724   else if (!TREE_SIDE_EFFECTS (expr))
8725     {
8726       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8727         warning_at (loc, OPT_Wunused_value, "statement with no effect");
8728     }
8729   else
8730     warn_if_unused_value (expr, loc);
8731 }
8732
8733 /* Process an expression as if it were a complete statement.  Emit
8734    diagnostics, but do not call ADD_STMT.  LOC is the location of the
8735    statement.  */
8736
8737 tree
8738 c_process_expr_stmt (location_t loc, tree expr)
8739 {
8740   if (!expr)
8741     return NULL_TREE;
8742
8743   expr = c_fully_fold (expr, false, NULL);
8744
8745   if (warn_sequence_point)
8746     verify_sequence_points (expr);
8747
8748   if (TREE_TYPE (expr) != error_mark_node
8749       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8750       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8751     error_at (loc, "expression statement has incomplete type");
8752
8753   /* If we're not processing a statement expression, warn about unused values.
8754      Warnings for statement expressions will be emitted later, once we figure
8755      out which is the result.  */
8756   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8757       && warn_unused_value)
8758     emit_side_effect_warnings (loc, expr);
8759
8760   /* If the expression is not of a type to which we cannot assign a line
8761      number, wrap the thing in a no-op NOP_EXPR.  */
8762   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8763     {
8764       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8765       SET_EXPR_LOCATION (expr, loc);
8766     }
8767
8768   return expr;
8769 }
8770
8771 /* Emit an expression as a statement.  LOC is the location of the
8772    expression.  */
8773
8774 tree
8775 c_finish_expr_stmt (location_t loc, tree expr)
8776 {
8777   if (expr)
8778     return add_stmt (c_process_expr_stmt (loc, expr));
8779   else
8780     return NULL;
8781 }
8782
8783 /* Do the opposite and emit a statement as an expression.  To begin,
8784    create a new binding level and return it.  */
8785
8786 tree
8787 c_begin_stmt_expr (void)
8788 {
8789   tree ret;
8790
8791   /* We must force a BLOCK for this level so that, if it is not expanded
8792      later, there is a way to turn off the entire subtree of blocks that
8793      are contained in it.  */
8794   keep_next_level ();
8795   ret = c_begin_compound_stmt (true);
8796
8797   c_bindings_start_stmt_expr (c_switch_stack == NULL
8798                               ? NULL
8799                               : c_switch_stack->bindings);
8800
8801   /* Mark the current statement list as belonging to a statement list.  */
8802   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8803
8804   return ret;
8805 }
8806
8807 /* LOC is the location of the compound statement to which this body
8808    belongs.  */
8809
8810 tree
8811 c_finish_stmt_expr (location_t loc, tree body)
8812 {
8813   tree last, type, tmp, val;
8814   tree *last_p;
8815
8816   body = c_end_compound_stmt (loc, body, true);
8817
8818   c_bindings_end_stmt_expr (c_switch_stack == NULL
8819                             ? NULL
8820                             : c_switch_stack->bindings);
8821
8822   /* Locate the last statement in BODY.  See c_end_compound_stmt
8823      about always returning a BIND_EXPR.  */
8824   last_p = &BIND_EXPR_BODY (body);
8825   last = BIND_EXPR_BODY (body);
8826
8827  continue_searching:
8828   if (TREE_CODE (last) == STATEMENT_LIST)
8829     {
8830       tree_stmt_iterator i;
8831
8832       /* This can happen with degenerate cases like ({ }).  No value.  */
8833       if (!TREE_SIDE_EFFECTS (last))
8834         return body;
8835
8836       /* If we're supposed to generate side effects warnings, process
8837          all of the statements except the last.  */
8838       if (warn_unused_value)
8839         {
8840           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8841             {
8842               location_t tloc;
8843               tree t = tsi_stmt (i);
8844
8845               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
8846               emit_side_effect_warnings (tloc, t);
8847             }
8848         }
8849       else
8850         i = tsi_last (last);
8851       last_p = tsi_stmt_ptr (i);
8852       last = *last_p;
8853     }
8854
8855   /* If the end of the list is exception related, then the list was split
8856      by a call to push_cleanup.  Continue searching.  */
8857   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8858       || TREE_CODE (last) == TRY_CATCH_EXPR)
8859     {
8860       last_p = &TREE_OPERAND (last, 0);
8861       last = *last_p;
8862       goto continue_searching;
8863     }
8864
8865   if (last == error_mark_node)
8866     return last;
8867
8868   /* In the case that the BIND_EXPR is not necessary, return the
8869      expression out from inside it.  */
8870   if (last == BIND_EXPR_BODY (body)
8871       && BIND_EXPR_VARS (body) == NULL)
8872     {
8873       /* Even if this looks constant, do not allow it in a constant
8874          expression.  */
8875       last = c_wrap_maybe_const (last, true);
8876       /* Do not warn if the return value of a statement expression is
8877          unused.  */
8878       TREE_NO_WARNING (last) = 1;
8879       return last;
8880     }
8881
8882   /* Extract the type of said expression.  */
8883   type = TREE_TYPE (last);
8884
8885   /* If we're not returning a value at all, then the BIND_EXPR that
8886      we already have is a fine expression to return.  */
8887   if (!type || VOID_TYPE_P (type))
8888     return body;
8889
8890   /* Now that we've located the expression containing the value, it seems
8891      silly to make voidify_wrapper_expr repeat the process.  Create a
8892      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8893   tmp = create_tmp_var_raw (type, NULL);
8894
8895   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8896      tree_expr_nonnegative_p giving up immediately.  */
8897   val = last;
8898   if (TREE_CODE (val) == NOP_EXPR
8899       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8900     val = TREE_OPERAND (val, 0);
8901
8902   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8903   SET_EXPR_LOCATION (*last_p, EXPR_LOCATION (last));
8904
8905   {
8906     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8907     SET_EXPR_LOCATION (t, loc);
8908     return t;
8909   }
8910 }
8911 \f
8912 /* Begin and end compound statements.  This is as simple as pushing
8913    and popping new statement lists from the tree.  */
8914
8915 tree
8916 c_begin_compound_stmt (bool do_scope)
8917 {
8918   tree stmt = push_stmt_list ();
8919   if (do_scope)
8920     push_scope ();
8921   return stmt;
8922 }
8923
8924 /* End a compound statement.  STMT is the statement.  LOC is the
8925    location of the compound statement-- this is usually the location
8926    of the opening brace.  */
8927
8928 tree
8929 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
8930 {
8931   tree block = NULL;
8932
8933   if (do_scope)
8934     {
8935       if (c_dialect_objc ())
8936         objc_clear_super_receiver ();
8937       block = pop_scope ();
8938     }
8939
8940   stmt = pop_stmt_list (stmt);
8941   stmt = c_build_bind_expr (loc, block, stmt);
8942
8943   /* If this compound statement is nested immediately inside a statement
8944      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8945      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8946      STATEMENT_LISTs merge, and thus we can lose track of what statement
8947      was really last.  */
8948   if (cur_stmt_list
8949       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8950       && TREE_CODE (stmt) != BIND_EXPR)
8951     {
8952       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8953       TREE_SIDE_EFFECTS (stmt) = 1;
8954       SET_EXPR_LOCATION (stmt, loc);
8955     }
8956
8957   return stmt;
8958 }
8959
8960 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8961    when the current scope is exited.  EH_ONLY is true when this is not
8962    meant to apply to normal control flow transfer.  */
8963
8964 void
8965 push_cleanup (tree decl, tree cleanup, bool eh_only)
8966 {
8967   enum tree_code code;
8968   tree stmt, list;
8969   bool stmt_expr;
8970
8971   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8972   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
8973   add_stmt (stmt);
8974   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8975   list = push_stmt_list ();
8976   TREE_OPERAND (stmt, 0) = list;
8977   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8978 }
8979 \f
8980 /* Build a binary-operation expression without default conversions.
8981    CODE is the kind of expression to build.
8982    LOCATION is the operator's location.
8983    This function differs from `build' in several ways:
8984    the data type of the result is computed and recorded in it,
8985    warnings are generated if arg data types are invalid,
8986    special handling for addition and subtraction of pointers is known,
8987    and some optimization is done (operations on narrow ints
8988    are done in the narrower type when that gives the same result).
8989    Constant folding is also done before the result is returned.
8990
8991    Note that the operands will never have enumeral types, or function
8992    or array types, because either they will have the default conversions
8993    performed or they have both just been converted to some other type in which
8994    the arithmetic is to be done.  */
8995
8996 tree
8997 build_binary_op (location_t location, enum tree_code code,
8998                  tree orig_op0, tree orig_op1, int convert_p)
8999 {
9000   tree type0, type1, orig_type0, orig_type1;
9001   tree eptype;
9002   enum tree_code code0, code1;
9003   tree op0, op1;
9004   tree ret = error_mark_node;
9005   const char *invalid_op_diag;
9006   bool op0_int_operands, op1_int_operands;
9007   bool int_const, int_const_or_overflow, int_operands;
9008
9009   /* Expression code to give to the expression when it is built.
9010      Normally this is CODE, which is what the caller asked for,
9011      but in some special cases we change it.  */
9012   enum tree_code resultcode = code;
9013
9014   /* Data type in which the computation is to be performed.
9015      In the simplest cases this is the common type of the arguments.  */
9016   tree result_type = NULL;
9017
9018   /* When the computation is in excess precision, the type of the
9019      final EXCESS_PRECISION_EXPR.  */
9020   tree real_result_type = NULL;
9021
9022   /* Nonzero means operands have already been type-converted
9023      in whatever way is necessary.
9024      Zero means they need to be converted to RESULT_TYPE.  */
9025   int converted = 0;
9026
9027   /* Nonzero means create the expression with this type, rather than
9028      RESULT_TYPE.  */
9029   tree build_type = 0;
9030
9031   /* Nonzero means after finally constructing the expression
9032      convert it to this type.  */
9033   tree final_type = 0;
9034
9035   /* Nonzero if this is an operation like MIN or MAX which can
9036      safely be computed in short if both args are promoted shorts.
9037      Also implies COMMON.
9038      -1 indicates a bitwise operation; this makes a difference
9039      in the exact conditions for when it is safe to do the operation
9040      in a narrower mode.  */
9041   int shorten = 0;
9042
9043   /* Nonzero if this is a comparison operation;
9044      if both args are promoted shorts, compare the original shorts.
9045      Also implies COMMON.  */
9046   int short_compare = 0;
9047
9048   /* Nonzero if this is a right-shift operation, which can be computed on the
9049      original short and then promoted if the operand is a promoted short.  */
9050   int short_shift = 0;
9051
9052   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
9053   int common = 0;
9054
9055   /* True means types are compatible as far as ObjC is concerned.  */
9056   bool objc_ok;
9057
9058   /* True means this is an arithmetic operation that may need excess
9059      precision.  */
9060   bool may_need_excess_precision;
9061
9062   if (location == UNKNOWN_LOCATION)
9063     location = input_location;
9064
9065   op0 = orig_op0;
9066   op1 = orig_op1;
9067
9068   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
9069   if (op0_int_operands)
9070     op0 = remove_c_maybe_const_expr (op0);
9071   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
9072   if (op1_int_operands)
9073     op1 = remove_c_maybe_const_expr (op1);
9074   int_operands = (op0_int_operands && op1_int_operands);
9075   if (int_operands)
9076     {
9077       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
9078                                && TREE_CODE (orig_op1) == INTEGER_CST);
9079       int_const = (int_const_or_overflow
9080                    && !TREE_OVERFLOW (orig_op0)
9081                    && !TREE_OVERFLOW (orig_op1));
9082     }
9083   else
9084     int_const = int_const_or_overflow = false;
9085
9086   if (convert_p)
9087     {
9088       op0 = default_conversion (op0);
9089       op1 = default_conversion (op1);
9090     }
9091
9092   orig_type0 = type0 = TREE_TYPE (op0);
9093   orig_type1 = type1 = TREE_TYPE (op1);
9094
9095   /* The expression codes of the data types of the arguments tell us
9096      whether the arguments are integers, floating, pointers, etc.  */
9097   code0 = TREE_CODE (type0);
9098   code1 = TREE_CODE (type1);
9099
9100   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
9101   STRIP_TYPE_NOPS (op0);
9102   STRIP_TYPE_NOPS (op1);
9103
9104   /* If an error was already reported for one of the arguments,
9105      avoid reporting another error.  */
9106
9107   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9108     return error_mark_node;
9109
9110   if ((invalid_op_diag
9111        = targetm.invalid_binary_op (code, type0, type1)))
9112     {
9113       error_at (location, invalid_op_diag);
9114       return error_mark_node;
9115     }
9116
9117   switch (code)
9118     {
9119     case PLUS_EXPR:
9120     case MINUS_EXPR:
9121     case MULT_EXPR:
9122     case TRUNC_DIV_EXPR:
9123     case CEIL_DIV_EXPR:
9124     case FLOOR_DIV_EXPR:
9125     case ROUND_DIV_EXPR:
9126     case EXACT_DIV_EXPR:
9127       may_need_excess_precision = true;
9128       break;
9129     default:
9130       may_need_excess_precision = false;
9131       break;
9132     }
9133   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
9134     {
9135       op0 = TREE_OPERAND (op0, 0);
9136       type0 = TREE_TYPE (op0);
9137     }
9138   else if (may_need_excess_precision
9139            && (eptype = excess_precision_type (type0)) != NULL_TREE)
9140     {
9141       type0 = eptype;
9142       op0 = convert (eptype, op0);
9143     }
9144   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
9145     {
9146       op1 = TREE_OPERAND (op1, 0);
9147       type1 = TREE_TYPE (op1);
9148     }
9149   else if (may_need_excess_precision
9150            && (eptype = excess_precision_type (type1)) != NULL_TREE)
9151     {
9152       type1 = eptype;
9153       op1 = convert (eptype, op1);
9154     }
9155
9156   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
9157
9158   switch (code)
9159     {
9160     case PLUS_EXPR:
9161       /* Handle the pointer + int case.  */
9162       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9163         {
9164           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
9165           goto return_build_binary_op;
9166         }
9167       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
9168         {
9169           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
9170           goto return_build_binary_op;
9171         }
9172       else
9173         common = 1;
9174       break;
9175
9176     case MINUS_EXPR:
9177       /* Subtraction of two similar pointers.
9178          We must subtract them as integers, then divide by object size.  */
9179       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
9180           && comp_target_types (location, type0, type1))
9181         {
9182           ret = pointer_diff (location, op0, op1);
9183           goto return_build_binary_op;
9184         }
9185       /* Handle pointer minus int.  Just like pointer plus int.  */
9186       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9187         {
9188           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
9189           goto return_build_binary_op;
9190         }
9191       else
9192         common = 1;
9193       break;
9194
9195     case MULT_EXPR:
9196       common = 1;
9197       break;
9198
9199     case TRUNC_DIV_EXPR:
9200     case CEIL_DIV_EXPR:
9201     case FLOOR_DIV_EXPR:
9202     case ROUND_DIV_EXPR:
9203     case EXACT_DIV_EXPR:
9204       warn_for_div_by_zero (location, op1);
9205
9206       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9207            || code0 == FIXED_POINT_TYPE
9208            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9209           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9210               || code1 == FIXED_POINT_TYPE
9211               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9212         {
9213           enum tree_code tcode0 = code0, tcode1 = code1;
9214
9215           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9216             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9217           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9218             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9219
9220           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9221               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9222             resultcode = RDIV_EXPR;
9223           else
9224             /* Although it would be tempting to shorten always here, that
9225                loses on some targets, since the modulo instruction is
9226                undefined if the quotient can't be represented in the
9227                computation mode.  We shorten only if unsigned or if
9228                dividing by something we know != -1.  */
9229             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9230                        || (TREE_CODE (op1) == INTEGER_CST
9231                            && !integer_all_onesp (op1)));
9232           common = 1;
9233         }
9234       break;
9235
9236     case BIT_AND_EXPR:
9237     case BIT_IOR_EXPR:
9238     case BIT_XOR_EXPR:
9239       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9240         shorten = -1;
9241       /* Allow vector types which are not floating point types.   */
9242       else if (code0 == VECTOR_TYPE
9243                && code1 == VECTOR_TYPE
9244                && !VECTOR_FLOAT_TYPE_P (type0)
9245                && !VECTOR_FLOAT_TYPE_P (type1))
9246         common = 1;
9247       break;
9248
9249     case TRUNC_MOD_EXPR:
9250     case FLOOR_MOD_EXPR:
9251       warn_for_div_by_zero (location, op1);
9252
9253       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9254           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9255           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9256         common = 1;
9257       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9258         {
9259           /* Although it would be tempting to shorten always here, that loses
9260              on some targets, since the modulo instruction is undefined if the
9261              quotient can't be represented in the computation mode.  We shorten
9262              only if unsigned or if dividing by something we know != -1.  */
9263           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9264                      || (TREE_CODE (op1) == INTEGER_CST
9265                          && !integer_all_onesp (op1)));
9266           common = 1;
9267         }
9268       break;
9269
9270     case TRUTH_ANDIF_EXPR:
9271     case TRUTH_ORIF_EXPR:
9272     case TRUTH_AND_EXPR:
9273     case TRUTH_OR_EXPR:
9274     case TRUTH_XOR_EXPR:
9275       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9276            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9277            || code0 == FIXED_POINT_TYPE)
9278           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9279               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9280               || code1 == FIXED_POINT_TYPE))
9281         {
9282           /* Result of these operations is always an int,
9283              but that does not mean the operands should be
9284              converted to ints!  */
9285           result_type = integer_type_node;
9286           op0 = c_common_truthvalue_conversion (location, op0);
9287           op1 = c_common_truthvalue_conversion (location, op1);
9288           converted = 1;
9289         }
9290       if (code == TRUTH_ANDIF_EXPR)
9291         {
9292           int_const_or_overflow = (int_operands
9293                                    && TREE_CODE (orig_op0) == INTEGER_CST
9294                                    && (op0 == truthvalue_false_node
9295                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9296           int_const = (int_const_or_overflow
9297                        && !TREE_OVERFLOW (orig_op0)
9298                        && (op0 == truthvalue_false_node
9299                            || !TREE_OVERFLOW (orig_op1)));
9300         }
9301       else if (code == TRUTH_ORIF_EXPR)
9302         {
9303           int_const_or_overflow = (int_operands
9304                                    && TREE_CODE (orig_op0) == INTEGER_CST
9305                                    && (op0 == truthvalue_true_node
9306                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9307           int_const = (int_const_or_overflow
9308                        && !TREE_OVERFLOW (orig_op0)
9309                        && (op0 == truthvalue_true_node
9310                            || !TREE_OVERFLOW (orig_op1)));
9311         }
9312       break;
9313
9314       /* Shift operations: result has same type as first operand;
9315          always convert second operand to int.
9316          Also set SHORT_SHIFT if shifting rightward.  */
9317
9318     case RSHIFT_EXPR:
9319       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9320           && code1 == INTEGER_TYPE)
9321         {
9322           if (TREE_CODE (op1) == INTEGER_CST)
9323             {
9324               if (tree_int_cst_sgn (op1) < 0)
9325                 {
9326                   int_const = false;
9327                   if (c_inhibit_evaluation_warnings == 0)
9328                     warning (0, "right shift count is negative");
9329                 }
9330               else
9331                 {
9332                   if (!integer_zerop (op1))
9333                     short_shift = 1;
9334
9335                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9336                     {
9337                       int_const = false;
9338                       if (c_inhibit_evaluation_warnings == 0)
9339                         warning (0, "right shift count >= width of type");
9340                     }
9341                 }
9342             }
9343
9344           /* Use the type of the value to be shifted.  */
9345           result_type = type0;
9346           /* Convert the shift-count to an integer, regardless of size
9347              of value being shifted.  */
9348           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9349             op1 = convert (integer_type_node, op1);
9350           /* Avoid converting op1 to result_type later.  */
9351           converted = 1;
9352         }
9353       break;
9354
9355     case LSHIFT_EXPR:
9356       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9357           && code1 == INTEGER_TYPE)
9358         {
9359           if (TREE_CODE (op1) == INTEGER_CST)
9360             {
9361               if (tree_int_cst_sgn (op1) < 0)
9362                 {
9363                   int_const = false;
9364                   if (c_inhibit_evaluation_warnings == 0)
9365                     warning (0, "left shift count is negative");
9366                 }
9367
9368               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9369                 {
9370                   int_const = false;
9371                   if (c_inhibit_evaluation_warnings == 0)
9372                     warning (0, "left shift count >= width of type");
9373                 }
9374             }
9375
9376           /* Use the type of the value to be shifted.  */
9377           result_type = type0;
9378           /* Convert the shift-count to an integer, regardless of size
9379              of value being shifted.  */
9380           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9381             op1 = convert (integer_type_node, op1);
9382           /* Avoid converting op1 to result_type later.  */
9383           converted = 1;
9384         }
9385       break;
9386
9387     case EQ_EXPR:
9388     case NE_EXPR:
9389       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9390         warning_at (location,
9391                     OPT_Wfloat_equal,
9392                     "comparing floating point with == or != is unsafe");
9393       /* Result of comparison is always int,
9394          but don't convert the args to int!  */
9395       build_type = integer_type_node;
9396       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9397            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9398           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9399               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9400         short_compare = 1;
9401       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9402         {
9403           tree tt0 = TREE_TYPE (type0);
9404           tree tt1 = TREE_TYPE (type1);
9405           addr_space_t as0 = TYPE_ADDR_SPACE (tt0);
9406           addr_space_t as1 = TYPE_ADDR_SPACE (tt1);
9407           addr_space_t as_common = ADDR_SPACE_GENERIC;
9408
9409           /* Anything compares with void *.  void * compares with anything.
9410              Otherwise, the targets must be compatible
9411              and both must be object or both incomplete.  */
9412           if (comp_target_types (location, type0, type1))
9413             result_type = common_pointer_type (type0, type1);
9414           else if (null_pointer_constant_p (orig_op0))
9415             result_type = type1;
9416           else if (null_pointer_constant_p (orig_op1))
9417             result_type = type0;
9418           else if (!addr_space_superset (as0, as1, &as_common))
9419             {
9420               error_at (location, "comparison of pointers to "
9421                         "disjoint address spaces");
9422               return error_mark_node;
9423             }
9424           else if (VOID_TYPE_P (tt0))
9425             {
9426               if (pedantic && TREE_CODE (tt1) == FUNCTION_TYPE)
9427                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9428                          "comparison of %<void *%> with function pointer");
9429             }
9430           else if (VOID_TYPE_P (tt1))
9431             {
9432               if (pedantic && TREE_CODE (tt0) == FUNCTION_TYPE)
9433                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9434                          "comparison of %<void *%> with function pointer");
9435             }
9436           else
9437             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9438             if (!objc_ok)
9439               pedwarn (location, 0,
9440                        "comparison of distinct pointer types lacks a cast");
9441
9442           if (result_type == NULL_TREE)
9443             {
9444               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9445               result_type = build_pointer_type
9446                               (build_qualified_type (void_type_node, qual));
9447             }
9448         }
9449       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9450         {
9451           if (TREE_CODE (op0) == ADDR_EXPR
9452               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9453             warning_at (location,
9454                         OPT_Waddress, "the address of %qD will never be NULL",
9455                         TREE_OPERAND (op0, 0));
9456           result_type = type0;
9457         }
9458       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9459         {
9460           if (TREE_CODE (op1) == ADDR_EXPR
9461               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9462             warning_at (location,
9463                         OPT_Waddress, "the address of %qD will never be NULL",
9464                         TREE_OPERAND (op1, 0));
9465           result_type = type1;
9466         }
9467       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9468         {
9469           result_type = type0;
9470           pedwarn (location, 0, "comparison between pointer and integer");
9471         }
9472       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9473         {
9474           result_type = type1;
9475           pedwarn (location, 0, "comparison between pointer and integer");
9476         }
9477       break;
9478
9479     case LE_EXPR:
9480     case GE_EXPR:
9481     case LT_EXPR:
9482     case GT_EXPR:
9483       build_type = integer_type_node;
9484       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9485            || code0 == FIXED_POINT_TYPE)
9486           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9487               || code1 == FIXED_POINT_TYPE))
9488         short_compare = 1;
9489       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9490         {
9491           addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (type0));
9492           addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
9493           addr_space_t as_common;
9494
9495           if (comp_target_types (location, type0, type1))
9496             {
9497               result_type = common_pointer_type (type0, type1);
9498               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9499                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9500                 pedwarn (location, 0,
9501                          "comparison of complete and incomplete pointers");
9502               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9503                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9504                          "ordered comparisons of pointers to functions");
9505             }
9506           else if (!addr_space_superset (as0, as1, &as_common))
9507             {
9508               error_at (location, "comparison of pointers to "
9509                         "disjoint address spaces");
9510               return error_mark_node;
9511             }
9512           else
9513             {
9514               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9515               result_type = build_pointer_type
9516                               (build_qualified_type (void_type_node, qual));
9517               pedwarn (location, 0,
9518                        "comparison of distinct pointer types lacks a cast");
9519             }
9520         }
9521       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9522         {
9523           result_type = type0;
9524           if (pedantic)
9525             pedwarn (location, OPT_pedantic,
9526                      "ordered comparison of pointer with integer zero");
9527           else if (extra_warnings)
9528             warning_at (location, OPT_Wextra,
9529                      "ordered comparison of pointer with integer zero");
9530         }
9531       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9532         {
9533           result_type = type1;
9534           pedwarn (location, OPT_pedantic,
9535                    "ordered comparison of pointer with integer zero");
9536         }
9537       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9538         {
9539           result_type = type0;
9540           pedwarn (location, 0, "comparison between pointer and integer");
9541         }
9542       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9543         {
9544           result_type = type1;
9545           pedwarn (location, 0, "comparison between pointer and integer");
9546         }
9547       break;
9548
9549     default:
9550       gcc_unreachable ();
9551     }
9552
9553   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9554     return error_mark_node;
9555
9556   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9557       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9558           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9559                                                     TREE_TYPE (type1))))
9560     {
9561       binary_op_error (location, code, type0, type1);
9562       return error_mark_node;
9563     }
9564
9565   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9566        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9567       &&
9568       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9569        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9570     {
9571       bool first_complex = (code0 == COMPLEX_TYPE);
9572       bool second_complex = (code1 == COMPLEX_TYPE);
9573       int none_complex = (!first_complex && !second_complex);
9574
9575       if (shorten || common || short_compare)
9576         {
9577           result_type = c_common_type (type0, type1);
9578           if (result_type == error_mark_node)
9579             return error_mark_node;
9580         }
9581
9582       if (first_complex != second_complex
9583           && (code == PLUS_EXPR
9584               || code == MINUS_EXPR
9585               || code == MULT_EXPR
9586               || (code == TRUNC_DIV_EXPR && first_complex))
9587           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9588           && flag_signed_zeros)
9589         {
9590           /* An operation on mixed real/complex operands must be
9591              handled specially, but the language-independent code can
9592              more easily optimize the plain complex arithmetic if
9593              -fno-signed-zeros.  */
9594           tree real_type = TREE_TYPE (result_type);
9595           tree real, imag;
9596           if (type0 != orig_type0 || type1 != orig_type1)
9597             {
9598               gcc_assert (may_need_excess_precision && common);
9599               real_result_type = c_common_type (orig_type0, orig_type1);
9600             }
9601           if (first_complex)
9602             {
9603               if (TREE_TYPE (op0) != result_type)
9604                 op0 = convert_and_check (result_type, op0);
9605               if (TREE_TYPE (op1) != real_type)
9606                 op1 = convert_and_check (real_type, op1);
9607             }
9608           else
9609             {
9610               if (TREE_TYPE (op0) != real_type)
9611                 op0 = convert_and_check (real_type, op0);
9612               if (TREE_TYPE (op1) != result_type)
9613                 op1 = convert_and_check (result_type, op1);
9614             }
9615           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9616             return error_mark_node;
9617           if (first_complex)
9618             {
9619               op0 = c_save_expr (op0);
9620               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
9621                                      op0, 1);
9622               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
9623                                      op0, 1);
9624               switch (code)
9625                 {
9626                 case MULT_EXPR:
9627                 case TRUNC_DIV_EXPR:
9628                   imag = build2 (resultcode, real_type, imag, op1);
9629                   /* Fall through.  */
9630                 case PLUS_EXPR:
9631                 case MINUS_EXPR:
9632                   real = build2 (resultcode, real_type, real, op1);
9633                   break;
9634                 default:
9635                   gcc_unreachable();
9636                 }
9637             }
9638           else
9639             {
9640               op1 = c_save_expr (op1);
9641               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
9642                                      op1, 1);
9643               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
9644                                      op1, 1);
9645               switch (code)
9646                 {
9647                 case MULT_EXPR:
9648                   imag = build2 (resultcode, real_type, op0, imag);
9649                   /* Fall through.  */
9650                 case PLUS_EXPR:
9651                   real = build2 (resultcode, real_type, op0, real);
9652                   break;
9653                 case MINUS_EXPR:
9654                   real = build2 (resultcode, real_type, op0, real);
9655                   imag = build1 (NEGATE_EXPR, real_type, imag);
9656                   break;
9657                 default:
9658                   gcc_unreachable();
9659                 }
9660             }
9661           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
9662           goto return_build_binary_op;
9663         }
9664
9665       /* For certain operations (which identify themselves by shorten != 0)
9666          if both args were extended from the same smaller type,
9667          do the arithmetic in that type and then extend.
9668
9669          shorten !=0 and !=1 indicates a bitwise operation.
9670          For them, this optimization is safe only if
9671          both args are zero-extended or both are sign-extended.
9672          Otherwise, we might change the result.
9673          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9674          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9675
9676       if (shorten && none_complex)
9677         {
9678           final_type = result_type;
9679           result_type = shorten_binary_op (result_type, op0, op1,
9680                                            shorten == -1);
9681         }
9682
9683       /* Shifts can be shortened if shifting right.  */
9684
9685       if (short_shift)
9686         {
9687           int unsigned_arg;
9688           tree arg0 = get_narrower (op0, &unsigned_arg);
9689
9690           final_type = result_type;
9691
9692           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9693             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9694
9695           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9696               && tree_int_cst_sgn (op1) > 0
9697               /* We can shorten only if the shift count is less than the
9698                  number of bits in the smaller type size.  */
9699               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9700               /* We cannot drop an unsigned shift after sign-extension.  */
9701               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9702             {
9703               /* Do an unsigned shift if the operand was zero-extended.  */
9704               result_type
9705                 = c_common_signed_or_unsigned_type (unsigned_arg,
9706                                                     TREE_TYPE (arg0));
9707               /* Convert value-to-be-shifted to that type.  */
9708               if (TREE_TYPE (op0) != result_type)
9709                 op0 = convert (result_type, op0);
9710               converted = 1;
9711             }
9712         }
9713
9714       /* Comparison operations are shortened too but differently.
9715          They identify themselves by setting short_compare = 1.  */
9716
9717       if (short_compare)
9718         {
9719           /* Don't write &op0, etc., because that would prevent op0
9720              from being kept in a register.
9721              Instead, make copies of the our local variables and
9722              pass the copies by reference, then copy them back afterward.  */
9723           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9724           enum tree_code xresultcode = resultcode;
9725           tree val
9726             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9727
9728           if (val != 0)
9729             {
9730               ret = val;
9731               goto return_build_binary_op;
9732             }
9733
9734           op0 = xop0, op1 = xop1;
9735           converted = 1;
9736           resultcode = xresultcode;
9737
9738           if (c_inhibit_evaluation_warnings == 0)
9739             {
9740               bool op0_maybe_const = true;
9741               bool op1_maybe_const = true;
9742               tree orig_op0_folded, orig_op1_folded;
9743
9744               if (in_late_binary_op)
9745                 {
9746                   orig_op0_folded = orig_op0;
9747                   orig_op1_folded = orig_op1;
9748                 }
9749               else
9750                 {
9751                   /* Fold for the sake of possible warnings, as in
9752                      build_conditional_expr.  This requires the
9753                      "original" values to be folded, not just op0 and
9754                      op1.  */
9755                   c_inhibit_evaluation_warnings++;
9756                   op0 = c_fully_fold (op0, require_constant_value,
9757                                       &op0_maybe_const);
9758                   op1 = c_fully_fold (op1, require_constant_value,
9759                                       &op1_maybe_const);
9760                   c_inhibit_evaluation_warnings--;
9761                   orig_op0_folded = c_fully_fold (orig_op0,
9762                                                   require_constant_value,
9763                                                   NULL);
9764                   orig_op1_folded = c_fully_fold (orig_op1,
9765                                                   require_constant_value,
9766                                                   NULL);
9767                 }
9768
9769               if (warn_sign_compare)
9770                 warn_for_sign_compare (location, orig_op0_folded,
9771                                        orig_op1_folded, op0, op1,
9772                                        result_type, resultcode);
9773               if (!in_late_binary_op)
9774                 {
9775                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9776                     op0 = c_wrap_maybe_const (op0, !op0_maybe_const);
9777                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9778                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
9779                 }
9780             }
9781         }
9782     }
9783
9784   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9785      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9786      Then the expression will be built.
9787      It will be given type FINAL_TYPE if that is nonzero;
9788      otherwise, it will be given type RESULT_TYPE.  */
9789
9790   if (!result_type)
9791     {
9792       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9793       return error_mark_node;
9794     }
9795
9796   if (!converted)
9797     {
9798       if (TREE_TYPE (op0) != result_type)
9799         op0 = convert_and_check (result_type, op0);
9800       if (TREE_TYPE (op1) != result_type)
9801         op1 = convert_and_check (result_type, op1);
9802
9803       /* This can happen if one operand has a vector type, and the other
9804          has a different type.  */
9805       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9806         return error_mark_node;
9807     }
9808
9809   if (build_type == NULL_TREE)
9810     {
9811       build_type = result_type;
9812       if (type0 != orig_type0 || type1 != orig_type1)
9813         {
9814           gcc_assert (may_need_excess_precision && common);
9815           real_result_type = c_common_type (orig_type0, orig_type1);
9816         }
9817     }
9818
9819   /* Treat expressions in initializers specially as they can't trap.  */
9820   if (int_const_or_overflow)
9821     ret = (require_constant_value
9822            ? fold_build2_initializer_loc (location, resultcode, build_type,
9823                                           op0, op1)
9824            : fold_build2_loc (location, resultcode, build_type, op0, op1));
9825   else
9826     ret = build2 (resultcode, build_type, op0, op1);
9827   if (final_type != 0)
9828     ret = convert (final_type, ret);
9829
9830  return_build_binary_op:
9831   gcc_assert (ret != error_mark_node);
9832   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9833     ret = (int_operands
9834            ? note_integer_operands (ret)
9835            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9836   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9837            && !in_late_binary_op)
9838     ret = note_integer_operands (ret);
9839   if (real_result_type)
9840     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9841   protected_set_expr_location (ret, location);
9842   return ret;
9843 }
9844
9845
9846 /* Convert EXPR to be a truth-value, validating its type for this
9847    purpose.  LOCATION is the source location for the expression.  */
9848
9849 tree
9850 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9851 {
9852   bool int_const, int_operands;
9853
9854   switch (TREE_CODE (TREE_TYPE (expr)))
9855     {
9856     case ARRAY_TYPE:
9857       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9858       return error_mark_node;
9859
9860     case RECORD_TYPE:
9861       error_at (location, "used struct type value where scalar is required");
9862       return error_mark_node;
9863
9864     case UNION_TYPE:
9865       error_at (location, "used union type value where scalar is required");
9866       return error_mark_node;
9867
9868     case FUNCTION_TYPE:
9869       gcc_unreachable ();
9870
9871     default:
9872       break;
9873     }
9874
9875   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9876   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9877   if (int_operands)
9878     expr = remove_c_maybe_const_expr (expr);
9879
9880   /* ??? Should we also give an error for void and vectors rather than
9881      leaving those to give errors later?  */
9882   expr = c_common_truthvalue_conversion (location, expr);
9883
9884   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9885     {
9886       if (TREE_OVERFLOW (expr))
9887         return expr;
9888       else
9889         return note_integer_operands (expr);
9890     }
9891   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9892     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9893   return expr;
9894 }
9895 \f
9896
9897 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9898    required.  */
9899
9900 tree
9901 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9902 {
9903   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9904     {
9905       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9906       /* Executing a compound literal inside a function reinitializes
9907          it.  */
9908       if (!TREE_STATIC (decl))
9909         *se = true;
9910       return decl;
9911     }
9912   else
9913     return expr;
9914 }
9915 \f
9916 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9917
9918 tree
9919 c_begin_omp_parallel (void)
9920 {
9921   tree block;
9922
9923   keep_next_level ();
9924   block = c_begin_compound_stmt (true);
9925
9926   return block;
9927 }
9928
9929 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
9930    statement.  LOC is the location of the OMP_PARALLEL.  */
9931
9932 tree
9933 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
9934 {
9935   tree stmt;
9936
9937   block = c_end_compound_stmt (loc, block, true);
9938
9939   stmt = make_node (OMP_PARALLEL);
9940   TREE_TYPE (stmt) = void_type_node;
9941   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9942   OMP_PARALLEL_BODY (stmt) = block;
9943   SET_EXPR_LOCATION (stmt, loc);
9944
9945   return add_stmt (stmt);
9946 }
9947
9948 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9949
9950 tree
9951 c_begin_omp_task (void)
9952 {
9953   tree block;
9954
9955   keep_next_level ();
9956   block = c_begin_compound_stmt (true);
9957
9958   return block;
9959 }
9960
9961 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
9962    statement.  LOC is the location of the #pragma.  */
9963
9964 tree
9965 c_finish_omp_task (location_t loc, tree clauses, tree block)
9966 {
9967   tree stmt;
9968
9969   block = c_end_compound_stmt (loc, block, true);
9970
9971   stmt = make_node (OMP_TASK);
9972   TREE_TYPE (stmt) = void_type_node;
9973   OMP_TASK_CLAUSES (stmt) = clauses;
9974   OMP_TASK_BODY (stmt) = block;
9975   SET_EXPR_LOCATION (stmt, loc);
9976
9977   return add_stmt (stmt);
9978 }
9979
9980 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9981    Remove any elements from the list that are invalid.  */
9982
9983 tree
9984 c_finish_omp_clauses (tree clauses)
9985 {
9986   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9987   tree c, t, *pc = &clauses;
9988   const char *name;
9989
9990   bitmap_obstack_initialize (NULL);
9991   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9992   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9993   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9994
9995   for (pc = &clauses, c = clauses; c ; c = *pc)
9996     {
9997       bool remove = false;
9998       bool need_complete = false;
9999       bool need_implicitly_determined = false;
10000
10001       switch (OMP_CLAUSE_CODE (c))
10002         {
10003         case OMP_CLAUSE_SHARED:
10004           name = "shared";
10005           need_implicitly_determined = true;
10006           goto check_dup_generic;
10007
10008         case OMP_CLAUSE_PRIVATE:
10009           name = "private";
10010           need_complete = true;
10011           need_implicitly_determined = true;
10012           goto check_dup_generic;
10013
10014         case OMP_CLAUSE_REDUCTION:
10015           name = "reduction";
10016           need_implicitly_determined = true;
10017           t = OMP_CLAUSE_DECL (c);
10018           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
10019               || POINTER_TYPE_P (TREE_TYPE (t)))
10020             {
10021               error_at (OMP_CLAUSE_LOCATION (c),
10022                         "%qE has invalid type for %<reduction%>", t);
10023               remove = true;
10024             }
10025           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
10026             {
10027               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
10028               const char *r_name = NULL;
10029
10030               switch (r_code)
10031                 {
10032                 case PLUS_EXPR:
10033                 case MULT_EXPR:
10034                 case MINUS_EXPR:
10035                   break;
10036                 case BIT_AND_EXPR:
10037                   r_name = "&";
10038                   break;
10039                 case BIT_XOR_EXPR:
10040                   r_name = "^";
10041                   break;
10042                 case BIT_IOR_EXPR:
10043                   r_name = "|";
10044                   break;
10045                 case TRUTH_ANDIF_EXPR:
10046                   r_name = "&&";
10047                   break;
10048                 case TRUTH_ORIF_EXPR:
10049                   r_name = "||";
10050                   break;
10051                 default:
10052                   gcc_unreachable ();
10053                 }
10054               if (r_name)
10055                 {
10056                   error_at (OMP_CLAUSE_LOCATION (c),
10057                             "%qE has invalid type for %<reduction(%s)%>",
10058                             t, r_name);
10059                   remove = true;
10060                 }
10061             }
10062           goto check_dup_generic;
10063
10064         case OMP_CLAUSE_COPYPRIVATE:
10065           name = "copyprivate";
10066           goto check_dup_generic;
10067
10068         case OMP_CLAUSE_COPYIN:
10069           name = "copyin";
10070           t = OMP_CLAUSE_DECL (c);
10071           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
10072             {
10073               error_at (OMP_CLAUSE_LOCATION (c),
10074                         "%qE must be %<threadprivate%> for %<copyin%>", t);
10075               remove = true;
10076             }
10077           goto check_dup_generic;
10078
10079         check_dup_generic:
10080           t = OMP_CLAUSE_DECL (c);
10081           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10082             {
10083               error_at (OMP_CLAUSE_LOCATION (c),
10084                         "%qE is not a variable in clause %qs", t, name);
10085               remove = true;
10086             }
10087           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10088                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
10089                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10090             {
10091               error_at (OMP_CLAUSE_LOCATION (c),
10092                         "%qE appears more than once in data clauses", t);
10093               remove = true;
10094             }
10095           else
10096             bitmap_set_bit (&generic_head, DECL_UID (t));
10097           break;
10098
10099         case OMP_CLAUSE_FIRSTPRIVATE:
10100           name = "firstprivate";
10101           t = OMP_CLAUSE_DECL (c);
10102           need_complete = true;
10103           need_implicitly_determined = true;
10104           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10105             {
10106               error_at (OMP_CLAUSE_LOCATION (c),
10107                         "%qE is not a variable in clause %<firstprivate%>", t);
10108               remove = true;
10109             }
10110           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10111                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
10112             {
10113               error_at (OMP_CLAUSE_LOCATION (c),
10114                         "%qE appears more than once in data clauses", t);
10115               remove = true;
10116             }
10117           else
10118             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
10119           break;
10120
10121         case OMP_CLAUSE_LASTPRIVATE:
10122           name = "lastprivate";
10123           t = OMP_CLAUSE_DECL (c);
10124           need_complete = true;
10125           need_implicitly_determined = true;
10126           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10127             {
10128               error_at (OMP_CLAUSE_LOCATION (c),
10129                         "%qE is not a variable in clause %<lastprivate%>", t);
10130               remove = true;
10131             }
10132           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10133                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10134             {
10135               error_at (OMP_CLAUSE_LOCATION (c),
10136                      "%qE appears more than once in data clauses", t);
10137               remove = true;
10138             }
10139           else
10140             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
10141           break;
10142
10143         case OMP_CLAUSE_IF:
10144         case OMP_CLAUSE_NUM_THREADS:
10145         case OMP_CLAUSE_SCHEDULE:
10146         case OMP_CLAUSE_NOWAIT:
10147         case OMP_CLAUSE_ORDERED:
10148         case OMP_CLAUSE_DEFAULT:
10149         case OMP_CLAUSE_UNTIED:
10150         case OMP_CLAUSE_COLLAPSE:
10151           pc = &OMP_CLAUSE_CHAIN (c);
10152           continue;
10153
10154         default:
10155           gcc_unreachable ();
10156         }
10157
10158       if (!remove)
10159         {
10160           t = OMP_CLAUSE_DECL (c);
10161
10162           if (need_complete)
10163             {
10164               t = require_complete_type (t);
10165               if (t == error_mark_node)
10166                 remove = true;
10167             }
10168
10169           if (need_implicitly_determined)
10170             {
10171               const char *share_name = NULL;
10172
10173               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
10174                 share_name = "threadprivate";
10175               else switch (c_omp_predetermined_sharing (t))
10176                 {
10177                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
10178                   break;
10179                 case OMP_CLAUSE_DEFAULT_SHARED:
10180                   share_name = "shared";
10181                   break;
10182                 case OMP_CLAUSE_DEFAULT_PRIVATE:
10183                   share_name = "private";
10184                   break;
10185                 default:
10186                   gcc_unreachable ();
10187                 }
10188               if (share_name)
10189                 {
10190                   error_at (OMP_CLAUSE_LOCATION (c),
10191                             "%qE is predetermined %qs for %qs",
10192                             t, share_name, name);
10193                   remove = true;
10194                 }
10195             }
10196         }
10197
10198       if (remove)
10199         *pc = OMP_CLAUSE_CHAIN (c);
10200       else
10201         pc = &OMP_CLAUSE_CHAIN (c);
10202     }
10203
10204   bitmap_obstack_release (NULL);
10205   return clauses;
10206 }
10207
10208 /* Make a variant type in the proper way for C/C++, propagating qualifiers
10209    down to the element type of an array.  */
10210
10211 tree
10212 c_build_qualified_type (tree type, int type_quals)
10213 {
10214   if (type == error_mark_node)
10215     return type;
10216
10217   if (TREE_CODE (type) == ARRAY_TYPE)
10218     {
10219       tree t;
10220       tree element_type = c_build_qualified_type (TREE_TYPE (type),
10221                                                   type_quals);
10222
10223       /* See if we already have an identically qualified type.  */
10224       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
10225         {
10226           if (TYPE_QUALS (strip_array_types (t)) == type_quals
10227               && TYPE_NAME (t) == TYPE_NAME (type)
10228               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
10229               && attribute_list_equal (TYPE_ATTRIBUTES (t),
10230                                        TYPE_ATTRIBUTES (type)))
10231             break;
10232         }
10233       if (!t)
10234         {
10235           tree domain = TYPE_DOMAIN (type);
10236
10237           t = build_variant_type_copy (type);
10238           TREE_TYPE (t) = element_type;
10239
10240           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
10241               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10242             SET_TYPE_STRUCTURAL_EQUALITY (t);
10243           else if (TYPE_CANONICAL (element_type) != element_type
10244                    || (domain && TYPE_CANONICAL (domain) != domain))
10245             {
10246               tree unqualified_canon
10247                 = build_array_type (TYPE_CANONICAL (element_type),
10248                                     domain? TYPE_CANONICAL (domain)
10249                                           : NULL_TREE);
10250               TYPE_CANONICAL (t)
10251                 = c_build_qualified_type (unqualified_canon, type_quals);
10252             }
10253           else
10254             TYPE_CANONICAL (t) = t;
10255         }
10256       return t;
10257     }
10258
10259   /* A restrict-qualified pointer type must be a pointer to object or
10260      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10261      REFERENCE_TYPEs, which is appropriate for C++.  */
10262   if ((type_quals & TYPE_QUAL_RESTRICT)
10263       && (!POINTER_TYPE_P (type)
10264           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10265     {
10266       error ("invalid use of %<restrict%>");
10267       type_quals &= ~TYPE_QUAL_RESTRICT;
10268     }
10269
10270   return build_qualified_type (type, type_quals);
10271 }
10272
10273 /* Build a VA_ARG_EXPR for the C parser.  */
10274
10275 tree
10276 c_build_va_arg (location_t loc, tree expr, tree type)
10277 {
10278   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10279     warning_at (loc, OPT_Wc___compat,
10280                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10281   return build_va_arg (loc, expr, type);
10282 }