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_UNION (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_UNION (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
4433           pedwarn (loc, OPT_pedantic, "ISO C forbids casts to union type");
4434           t = digest_init (loc, type,
4435                            build_constructor_single (type, field, value),
4436                            NULL_TREE, false, true, 0);
4437           TREE_CONSTANT (t) = TREE_CONSTANT (value);
4438           return t;
4439         }
4440       error_at (loc, "cast to union type from type not present in union");
4441       return error_mark_node;
4442     }
4443   else
4444     {
4445       tree otype, ovalue;
4446
4447       if (type == void_type_node)
4448         {
4449           tree t = build1 (CONVERT_EXPR, type, value);
4450           SET_EXPR_LOCATION (t, loc);
4451           return t;
4452         }
4453
4454       otype = TREE_TYPE (value);
4455
4456       /* Optionally warn about potentially worrisome casts.  */
4457       if (warn_cast_qual
4458           && TREE_CODE (type) == POINTER_TYPE
4459           && TREE_CODE (otype) == POINTER_TYPE)
4460         handle_warn_cast_qual (type, otype);
4461
4462       /* Warn about conversions between pointers to disjoint
4463          address spaces.  */
4464       if (TREE_CODE (type) == POINTER_TYPE
4465           && TREE_CODE (otype) == POINTER_TYPE
4466           && !null_pointer_constant_p (value))
4467         {
4468           addr_space_t as_to = TYPE_ADDR_SPACE (TREE_TYPE (type));
4469           addr_space_t as_from = TYPE_ADDR_SPACE (TREE_TYPE (otype));
4470           addr_space_t as_common;
4471
4472           if (!addr_space_superset (as_to, as_from, &as_common))
4473             {
4474               if (ADDR_SPACE_GENERIC_P (as_from))
4475                 warning_at (loc, 0, "cast to %s address space pointer "
4476                             "from disjoint generic address space pointer",
4477                             c_addr_space_name (as_to));
4478
4479               else if (ADDR_SPACE_GENERIC_P (as_to))
4480                 warning_at (loc, 0, "cast to generic address space pointer "
4481                             "from disjoint %s address space pointer",
4482                             c_addr_space_name (as_from));
4483
4484               else
4485                 warning_at (loc, 0, "cast to %s address space pointer "
4486                             "from disjoint %s address space pointer",
4487                             c_addr_space_name (as_to),
4488                             c_addr_space_name (as_from));
4489             }
4490         }
4491
4492       /* Warn about possible alignment problems.  */
4493       if (STRICT_ALIGNMENT
4494           && TREE_CODE (type) == POINTER_TYPE
4495           && TREE_CODE (otype) == POINTER_TYPE
4496           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4497           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4498           /* Don't warn about opaque types, where the actual alignment
4499              restriction is unknown.  */
4500           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
4501                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
4502                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
4503           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4504         warning_at (loc, OPT_Wcast_align,
4505                     "cast increases required alignment of target type");
4506
4507       if (TREE_CODE (type) == INTEGER_TYPE
4508           && TREE_CODE (otype) == POINTER_TYPE
4509           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4510       /* Unlike conversion of integers to pointers, where the
4511          warning is disabled for converting constants because
4512          of cases such as SIG_*, warn about converting constant
4513          pointers to integers. In some cases it may cause unwanted
4514          sign extension, and a warning is appropriate.  */
4515         warning_at (loc, OPT_Wpointer_to_int_cast,
4516                     "cast from pointer to integer of different size");
4517
4518       if (TREE_CODE (value) == CALL_EXPR
4519           && TREE_CODE (type) != TREE_CODE (otype))
4520         warning_at (loc, OPT_Wbad_function_cast,
4521                     "cast from function call of type %qT "
4522                     "to non-matching type %qT", otype, type);
4523
4524       if (TREE_CODE (type) == POINTER_TYPE
4525           && TREE_CODE (otype) == INTEGER_TYPE
4526           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4527           /* Don't warn about converting any constant.  */
4528           && !TREE_CONSTANT (value))
4529         warning_at (loc,
4530                     OPT_Wint_to_pointer_cast, "cast to pointer from integer "
4531                     "of different size");
4532
4533       if (warn_strict_aliasing <= 2)
4534         strict_aliasing_warning (otype, type, expr);
4535
4536       /* If pedantic, warn for conversions between function and object
4537          pointer types, except for converting a null pointer constant
4538          to function pointer type.  */
4539       if (pedantic
4540           && TREE_CODE (type) == POINTER_TYPE
4541           && TREE_CODE (otype) == POINTER_TYPE
4542           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
4543           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
4544         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4545                  "conversion of function pointer to object pointer type");
4546
4547       if (pedantic
4548           && TREE_CODE (type) == POINTER_TYPE
4549           && TREE_CODE (otype) == POINTER_TYPE
4550           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
4551           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4552           && !null_pointer_constant_p (value))
4553         pedwarn (loc, OPT_pedantic, "ISO C forbids "
4554                  "conversion of object pointer to function pointer type");
4555
4556       ovalue = value;
4557       value = convert (type, value);
4558
4559       /* Ignore any integer overflow caused by the cast.  */
4560       if (TREE_CODE (value) == INTEGER_CST && !FLOAT_TYPE_P (otype))
4561         {
4562           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
4563             {
4564               if (!TREE_OVERFLOW (value))
4565                 {
4566                   /* Avoid clobbering a shared constant.  */
4567                   value = copy_node (value);
4568                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4569                 }
4570             }
4571           else if (TREE_OVERFLOW (value))
4572             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
4573             value = build_int_cst_wide (TREE_TYPE (value),
4574                                         TREE_INT_CST_LOW (value),
4575                                         TREE_INT_CST_HIGH (value));
4576         }
4577     }
4578
4579   /* Don't let a cast be an lvalue.  */
4580   if (value == expr)
4581     value = non_lvalue_loc (loc, value);
4582
4583   /* Don't allow the results of casting to floating-point or complex
4584      types be confused with actual constants, or casts involving
4585      integer and pointer types other than direct integer-to-integer
4586      and integer-to-pointer be confused with integer constant
4587      expressions and null pointer constants.  */
4588   if (TREE_CODE (value) == REAL_CST
4589       || TREE_CODE (value) == COMPLEX_CST
4590       || (TREE_CODE (value) == INTEGER_CST
4591           && !((TREE_CODE (expr) == INTEGER_CST
4592                 && INTEGRAL_TYPE_P (TREE_TYPE (expr)))
4593                || TREE_CODE (expr) == REAL_CST
4594                || TREE_CODE (expr) == COMPLEX_CST)))
4595       value = build1 (NOP_EXPR, type, value);
4596
4597   if (CAN_HAVE_LOCATION_P (value))
4598     SET_EXPR_LOCATION (value, loc);
4599   return value;
4600 }
4601
4602 /* Interpret a cast of expression EXPR to type TYPE.  LOC is the
4603    location of the open paren of the cast, or the position of the cast
4604    expr.  */
4605 tree
4606 c_cast_expr (location_t loc, struct c_type_name *type_name, tree expr)
4607 {
4608   tree type;
4609   tree type_expr = NULL_TREE;
4610   bool type_expr_const = true;
4611   tree ret;
4612   int saved_wsp = warn_strict_prototypes;
4613
4614   /* This avoids warnings about unprototyped casts on
4615      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
4616   if (TREE_CODE (expr) == INTEGER_CST)
4617     warn_strict_prototypes = 0;
4618   type = groktypename (type_name, &type_expr, &type_expr_const);
4619   warn_strict_prototypes = saved_wsp;
4620
4621   ret = build_c_cast (loc, type, expr);
4622   if (type_expr)
4623     {
4624       ret = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret), type_expr, ret);
4625       C_MAYBE_CONST_EXPR_NON_CONST (ret) = !type_expr_const;
4626       SET_EXPR_LOCATION (ret, loc);
4627     }
4628
4629   if (CAN_HAVE_LOCATION_P (ret) && !EXPR_HAS_LOCATION (ret))
4630     SET_EXPR_LOCATION (ret, loc);
4631
4632   /* C++ does not permits types to be defined in a cast.  */
4633   if (warn_cxx_compat && type_name->specs->tag_defined_p)
4634     warning_at (loc, OPT_Wc___compat,
4635                 "defining a type in a cast is invalid in C++");
4636
4637   return ret;
4638 }
4639 \f
4640 /* Build an assignment expression of lvalue LHS from value RHS.
4641    If LHS_ORIGTYPE is not NULL, it is the original type of LHS, which
4642    may differ from TREE_TYPE (LHS) for an enum bitfield.
4643    MODIFYCODE is the code for a binary operator that we use
4644    to combine the old value of LHS with RHS to get the new value.
4645    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4646    If RHS_ORIGTYPE is not NULL_TREE, it is the original type of RHS,
4647    which may differ from TREE_TYPE (RHS) for an enum value.
4648
4649    LOCATION is the location of the MODIFYCODE operator.
4650    RHS_LOC is the location of the RHS.  */
4651
4652 tree
4653 build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
4654                    enum tree_code modifycode,
4655                    location_t rhs_loc, tree rhs, tree rhs_origtype)
4656 {
4657   tree result;
4658   tree newrhs;
4659   tree rhs_semantic_type = NULL_TREE;
4660   tree lhstype = TREE_TYPE (lhs);
4661   tree olhstype = lhstype;
4662   bool npc;
4663
4664   /* Types that aren't fully specified cannot be used in assignments.  */
4665   lhs = require_complete_type (lhs);
4666
4667   /* Avoid duplicate error messages from operands that had errors.  */
4668   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
4669     return error_mark_node;
4670
4671   if (!lvalue_or_else (lhs, lv_assign))
4672     return error_mark_node;
4673
4674   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4675     {
4676       rhs_semantic_type = TREE_TYPE (rhs);
4677       rhs = TREE_OPERAND (rhs, 0);
4678     }
4679
4680   newrhs = rhs;
4681
4682   if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR)
4683     {
4684       tree inner = build_modify_expr (location, C_MAYBE_CONST_EXPR_EXPR (lhs),
4685                                       lhs_origtype, modifycode, rhs_loc, rhs,
4686                                       rhs_origtype);
4687       if (inner == error_mark_node)
4688         return error_mark_node;
4689       result = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (inner),
4690                        C_MAYBE_CONST_EXPR_PRE (lhs), inner);
4691       gcc_assert (!C_MAYBE_CONST_EXPR_INT_OPERANDS (lhs));
4692       C_MAYBE_CONST_EXPR_NON_CONST (result) = 1;
4693       protected_set_expr_location (result, location);
4694       return result;
4695     }
4696
4697   /* If a binary op has been requested, combine the old LHS value with the RHS
4698      producing the value we should actually store into the LHS.  */
4699
4700   if (modifycode != NOP_EXPR)
4701     {
4702       lhs = c_fully_fold (lhs, false, NULL);
4703       lhs = stabilize_reference (lhs);
4704       newrhs = build_binary_op (location,
4705                                 modifycode, lhs, rhs, 1);
4706
4707       /* The original type of the right hand side is no longer
4708          meaningful.  */
4709       rhs_origtype = NULL_TREE;
4710     }
4711
4712   /* Give an error for storing in something that is 'const'.  */
4713
4714   if (TYPE_READONLY (lhstype)
4715       || ((TREE_CODE (lhstype) == RECORD_TYPE
4716            || TREE_CODE (lhstype) == UNION_TYPE)
4717           && C_TYPE_FIELDS_READONLY (lhstype)))
4718     {
4719       readonly_error (lhs, lv_assign);
4720       return error_mark_node;
4721     }
4722   else if (TREE_READONLY (lhs))
4723     readonly_warning (lhs, lv_assign);
4724
4725   /* If storing into a structure or union member,
4726      it has probably been given type `int'.
4727      Compute the type that would go with
4728      the actual amount of storage the member occupies.  */
4729
4730   if (TREE_CODE (lhs) == COMPONENT_REF
4731       && (TREE_CODE (lhstype) == INTEGER_TYPE
4732           || TREE_CODE (lhstype) == BOOLEAN_TYPE
4733           || TREE_CODE (lhstype) == REAL_TYPE
4734           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
4735     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
4736
4737   /* If storing in a field that is in actuality a short or narrower than one,
4738      we must store in the field in its actual type.  */
4739
4740   if (lhstype != TREE_TYPE (lhs))
4741     {
4742       lhs = copy_node (lhs);
4743       TREE_TYPE (lhs) = lhstype;
4744     }
4745
4746   /* Issue -Wc++-compat warnings about an assignment to an enum type
4747      when LHS does not have its original type.  This happens for,
4748      e.g., an enum bitfield in a struct.  */
4749   if (warn_cxx_compat
4750       && lhs_origtype != NULL_TREE
4751       && lhs_origtype != lhstype
4752       && TREE_CODE (lhs_origtype) == ENUMERAL_TYPE)
4753     {
4754       tree checktype = (rhs_origtype != NULL_TREE
4755                         ? rhs_origtype
4756                         : TREE_TYPE (rhs));
4757       if (checktype != error_mark_node
4758           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (lhs_origtype))
4759         warning_at (location, OPT_Wc___compat,
4760                     "enum conversion in assignment is invalid in C++");
4761     }
4762
4763   /* Convert new value to destination type.  Fold it first, then
4764      restore any excess precision information, for the sake of
4765      conversion warnings.  */
4766
4767   npc = null_pointer_constant_p (newrhs);
4768   newrhs = c_fully_fold (newrhs, false, NULL);
4769   if (rhs_semantic_type)
4770     newrhs = build1 (EXCESS_PRECISION_EXPR, rhs_semantic_type, newrhs);
4771   newrhs = convert_for_assignment (location, lhstype, newrhs, rhs_origtype,
4772                                    ic_assign, npc, NULL_TREE, NULL_TREE, 0);
4773   if (TREE_CODE (newrhs) == ERROR_MARK)
4774     return error_mark_node;
4775
4776   /* Emit ObjC write barrier, if necessary.  */
4777   if (c_dialect_objc () && flag_objc_gc)
4778     {
4779       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
4780       if (result)
4781         {
4782           protected_set_expr_location (result, location);
4783           return result;
4784         }
4785     }
4786
4787   /* Scan operands.  */
4788
4789   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
4790   TREE_SIDE_EFFECTS (result) = 1;
4791   protected_set_expr_location (result, location);
4792
4793   /* If we got the LHS in a different type for storing in,
4794      convert the result back to the nominal type of LHS
4795      so that the value we return always has the same type
4796      as the LHS argument.  */
4797
4798   if (olhstype == TREE_TYPE (result))
4799     return result;
4800
4801   result = convert_for_assignment (location, olhstype, result, rhs_origtype,
4802                                    ic_assign, false, NULL_TREE, NULL_TREE, 0);
4803   protected_set_expr_location (result, location);
4804   return result;
4805 }
4806 \f
4807 /* Convert value RHS to type TYPE as preparation for an assignment to
4808    an lvalue of type TYPE.  If ORIGTYPE is not NULL_TREE, it is the
4809    original type of RHS; this differs from TREE_TYPE (RHS) for enum
4810    types.  NULL_POINTER_CONSTANT says whether RHS was a null pointer
4811    constant before any folding.
4812    The real work of conversion is done by `convert'.
4813    The purpose of this function is to generate error messages
4814    for assignments that are not allowed in C.
4815    ERRTYPE says whether it is argument passing, assignment,
4816    initialization or return.
4817
4818    LOCATION is the location of the RHS.
4819    FUNCTION is a tree for the function being called.
4820    PARMNUM is the number of the argument, for printing in error messages.  */
4821
4822 static tree
4823 convert_for_assignment (location_t location, tree type, tree rhs,
4824                         tree origtype, enum impl_conv errtype,
4825                         bool null_pointer_constant, tree fundecl,
4826                         tree function, int parmnum)
4827 {
4828   enum tree_code codel = TREE_CODE (type);
4829   tree orig_rhs = rhs;
4830   tree rhstype;
4831   enum tree_code coder;
4832   tree rname = NULL_TREE;
4833   bool objc_ok = false;
4834
4835   if (errtype == ic_argpass)
4836     {
4837       tree selector;
4838       /* Change pointer to function to the function itself for
4839          diagnostics.  */
4840       if (TREE_CODE (function) == ADDR_EXPR
4841           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
4842         function = TREE_OPERAND (function, 0);
4843
4844       /* Handle an ObjC selector specially for diagnostics.  */
4845       selector = objc_message_selector ();
4846       rname = function;
4847       if (selector && parmnum > 2)
4848         {
4849           rname = selector;
4850           parmnum -= 2;
4851         }
4852     }
4853
4854   /* This macro is used to emit diagnostics to ensure that all format
4855      strings are complete sentences, visible to gettext and checked at
4856      compile time.  */
4857 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4858   do {                                                                   \
4859     switch (errtype)                                                     \
4860       {                                                                  \
4861       case ic_argpass:                                                   \
4862         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4863           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4864                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4865                   "expected %qT but argument is of type %qT",            \
4866                   type, rhstype);                                        \
4867         break;                                                           \
4868       case ic_assign:                                                    \
4869         pedwarn (LOCATION, OPT, AS);                                     \
4870         break;                                                           \
4871       case ic_init:                                                      \
4872         pedwarn (LOCATION, OPT, IN);                                     \
4873         break;                                                           \
4874       case ic_return:                                                    \
4875         pedwarn (LOCATION, OPT, RE);                                     \
4876         break;                                                           \
4877       default:                                                           \
4878         gcc_unreachable ();                                              \
4879       }                                                                  \
4880   } while (0)
4881
4882   if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
4883     rhs = TREE_OPERAND (rhs, 0);
4884
4885   rhstype = TREE_TYPE (rhs);
4886   coder = TREE_CODE (rhstype);
4887
4888   if (coder == ERROR_MARK)
4889     return error_mark_node;
4890
4891   if (c_dialect_objc ())
4892     {
4893       int parmno;
4894
4895       switch (errtype)
4896         {
4897         case ic_return:
4898           parmno = 0;
4899           break;
4900
4901         case ic_assign:
4902           parmno = -1;
4903           break;
4904
4905         case ic_init:
4906           parmno = -2;
4907           break;
4908
4909         default:
4910           parmno = parmnum;
4911           break;
4912         }
4913
4914       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4915     }
4916
4917   if (warn_cxx_compat)
4918     {
4919       tree checktype = origtype != NULL_TREE ? origtype : rhstype;
4920       if (checktype != error_mark_node
4921           && TREE_CODE (type) == ENUMERAL_TYPE
4922           && TYPE_MAIN_VARIANT (checktype) != TYPE_MAIN_VARIANT (type))
4923         {
4924           WARN_FOR_ASSIGNMENT (input_location, OPT_Wc___compat,
4925                                G_("enum conversion when passing argument "
4926                                   "%d of %qE is invalid in C++"),
4927                                G_("enum conversion in assignment is "
4928                                   "invalid in C++"),
4929                                G_("enum conversion in initialization is "
4930                                   "invalid in C++"),
4931                                G_("enum conversion in return is "
4932                                   "invalid in C++"));
4933         }
4934     }
4935
4936   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4937     return rhs;
4938
4939   if (coder == VOID_TYPE)
4940     {
4941       /* Except for passing an argument to an unprototyped function,
4942          this is a constraint violation.  When passing an argument to
4943          an unprototyped function, it is compile-time undefined;
4944          making it a constraint in that case was rejected in
4945          DR#252.  */
4946       error_at (location, "void value not ignored as it ought to be");
4947       return error_mark_node;
4948     }
4949   rhs = require_complete_type (rhs);
4950   if (rhs == error_mark_node)
4951     return error_mark_node;
4952   /* A type converts to a reference to it.
4953      This code doesn't fully support references, it's just for the
4954      special case of va_start and va_copy.  */
4955   if (codel == REFERENCE_TYPE
4956       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4957     {
4958       if (!lvalue_p (rhs))
4959         {
4960           error_at (location, "cannot pass rvalue to reference parameter");
4961           return error_mark_node;
4962         }
4963       if (!c_mark_addressable (rhs))
4964         return error_mark_node;
4965       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4966       SET_EXPR_LOCATION (rhs, location);
4967
4968       /* We already know that these two types are compatible, but they
4969          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4970          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4971          likely to be va_list, a typedef to __builtin_va_list, which
4972          is different enough that it will cause problems later.  */
4973       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4974         {
4975           rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4976           SET_EXPR_LOCATION (rhs, location);
4977         }
4978
4979       rhs = build1 (NOP_EXPR, type, rhs);
4980       SET_EXPR_LOCATION (rhs, location);
4981       return rhs;
4982     }
4983   /* Some types can interconvert without explicit casts.  */
4984   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4985            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4986     return convert (type, rhs);
4987   /* Arithmetic types all interconvert, and enum is treated like int.  */
4988   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4989             || codel == FIXED_POINT_TYPE
4990             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4991             || codel == BOOLEAN_TYPE)
4992            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4993                || coder == FIXED_POINT_TYPE
4994                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4995                || coder == BOOLEAN_TYPE))
4996     {
4997       tree ret;
4998       bool save = in_late_binary_op;
4999       if (codel == BOOLEAN_TYPE)
5000         in_late_binary_op = true;
5001       ret = convert_and_check (type, orig_rhs);
5002       if (codel == BOOLEAN_TYPE)
5003         in_late_binary_op = save;
5004       return ret;
5005     }
5006
5007   /* Aggregates in different TUs might need conversion.  */
5008   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
5009       && codel == coder
5010       && comptypes (type, rhstype))
5011     return convert_and_check (type, rhs);
5012
5013   /* Conversion to a transparent union from its member types.
5014      This applies only to function arguments.  */
5015   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
5016       && errtype == ic_argpass)
5017     {
5018       tree memb, marginal_memb = NULL_TREE;
5019
5020       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
5021         {
5022           tree memb_type = TREE_TYPE (memb);
5023
5024           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
5025                          TYPE_MAIN_VARIANT (rhstype)))
5026             break;
5027
5028           if (TREE_CODE (memb_type) != POINTER_TYPE)
5029             continue;
5030
5031           if (coder == POINTER_TYPE)
5032             {
5033               tree ttl = TREE_TYPE (memb_type);
5034               tree ttr = TREE_TYPE (rhstype);
5035
5036               /* Any non-function converts to a [const][volatile] void *
5037                  and vice versa; otherwise, targets must be the same.
5038                  Meanwhile, the lhs target must have all the qualifiers of
5039                  the rhs.  */
5040               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5041                   || comp_target_types (location, memb_type, rhstype))
5042                 {
5043                   /* If this type won't generate any warnings, use it.  */
5044                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
5045                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
5046                            && TREE_CODE (ttl) == FUNCTION_TYPE)
5047                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5048                              == TYPE_QUALS (ttr))
5049                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
5050                              == TYPE_QUALS (ttl))))
5051                     break;
5052
5053                   /* Keep looking for a better type, but remember this one.  */
5054                   if (!marginal_memb)
5055                     marginal_memb = memb;
5056                 }
5057             }
5058
5059           /* Can convert integer zero to any pointer type.  */
5060           if (null_pointer_constant)
5061             {
5062               rhs = null_pointer_node;
5063               break;
5064             }
5065         }
5066
5067       if (memb || marginal_memb)
5068         {
5069           if (!memb)
5070             {
5071               /* We have only a marginally acceptable member type;
5072                  it needs a warning.  */
5073               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
5074               tree ttr = TREE_TYPE (rhstype);
5075
5076               /* Const and volatile mean something different for function
5077                  types, so the usual warnings are not appropriate.  */
5078               if (TREE_CODE (ttr) == FUNCTION_TYPE
5079                   && TREE_CODE (ttl) == FUNCTION_TYPE)
5080                 {
5081                   /* Because const and volatile on functions are
5082                      restrictions that say the function will not do
5083                      certain things, it is okay to use a const or volatile
5084                      function where an ordinary one is wanted, but not
5085                      vice-versa.  */
5086                   if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5087                       & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5088                     WARN_FOR_ASSIGNMENT (location, 0,
5089                                          G_("passing argument %d of %qE "
5090                                             "makes qualified function "
5091                                             "pointer from unqualified"),
5092                                          G_("assignment makes qualified "
5093                                             "function pointer from "
5094                                             "unqualified"),
5095                                          G_("initialization makes qualified "
5096                                             "function pointer from "
5097                                             "unqualified"),
5098                                          G_("return makes qualified function "
5099                                             "pointer from unqualified"));
5100                 }
5101               else if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5102                        & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5103                 WARN_FOR_ASSIGNMENT (location, 0,
5104                                      G_("passing argument %d of %qE discards "
5105                                         "qualifiers from pointer target type"),
5106                                      G_("assignment discards qualifiers "
5107                                         "from pointer target type"),
5108                                      G_("initialization discards qualifiers "
5109                                         "from pointer target type"),
5110                                      G_("return discards qualifiers from "
5111                                         "pointer target type"));
5112
5113               memb = marginal_memb;
5114             }
5115
5116           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
5117             pedwarn (location, OPT_pedantic,
5118                      "ISO C prohibits argument conversion to union type");
5119
5120           rhs = fold_convert_loc (location, TREE_TYPE (memb), rhs);
5121           return build_constructor_single (type, memb, rhs);
5122         }
5123     }
5124
5125   /* Conversions among pointers */
5126   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
5127            && (coder == codel))
5128     {
5129       tree ttl = TREE_TYPE (type);
5130       tree ttr = TREE_TYPE (rhstype);
5131       tree mvl = ttl;
5132       tree mvr = ttr;
5133       bool is_opaque_pointer;
5134       int target_cmp = 0;   /* Cache comp_target_types () result.  */
5135       addr_space_t asl;
5136       addr_space_t asr;
5137
5138       if (TREE_CODE (mvl) != ARRAY_TYPE)
5139         mvl = TYPE_MAIN_VARIANT (mvl);
5140       if (TREE_CODE (mvr) != ARRAY_TYPE)
5141         mvr = TYPE_MAIN_VARIANT (mvr);
5142       /* Opaque pointers are treated like void pointers.  */
5143       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
5144
5145       /* C++ does not allow the implicit conversion void* -> T*.  However,
5146          for the purpose of reducing the number of false positives, we
5147          tolerate the special case of
5148
5149                 int *p = NULL;
5150
5151          where NULL is typically defined in C to be '(void *) 0'.  */
5152       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
5153         warning_at (location, OPT_Wc___compat,
5154                     "request for implicit conversion "
5155                     "from %qT to %qT not permitted in C++", rhstype, type);
5156
5157       /* See if the pointers point to incompatible address spaces.  */
5158       asl = TYPE_ADDR_SPACE (ttl);
5159       asr = TYPE_ADDR_SPACE (ttr);
5160       if (!null_pointer_constant_p (rhs)
5161           && asr != asl && !targetm.addr_space.subset_p (asr, asl))
5162         {
5163           switch (errtype)
5164             {
5165             case ic_argpass:
5166               error_at (location, "passing argument %d of %qE from pointer to "
5167                         "non-enclosed address space", parmnum, rname);
5168               break;
5169             case ic_assign:
5170               error_at (location, "assignment from pointer to "
5171                         "non-enclosed address space");
5172               break;
5173             case ic_init:
5174               error_at (location, "initialization from pointer to "
5175                         "non-enclosed address space");
5176               break;
5177             case ic_return:
5178               error_at (location, "return from pointer to "
5179                         "non-enclosed address space");
5180               break;
5181             default:
5182               gcc_unreachable ();
5183             }
5184           return error_mark_node;
5185         }
5186
5187       /* Check if the right-hand side has a format attribute but the
5188          left-hand side doesn't.  */
5189       if (warn_missing_format_attribute
5190           && check_missing_format_attribute (type, rhstype))
5191         {
5192           switch (errtype)
5193           {
5194           case ic_argpass:
5195             warning_at (location, OPT_Wmissing_format_attribute,
5196                         "argument %d of %qE might be "
5197                         "a candidate for a format attribute",
5198                         parmnum, rname);
5199             break;
5200           case ic_assign:
5201             warning_at (location, OPT_Wmissing_format_attribute,
5202                         "assignment left-hand side might be "
5203                         "a candidate for a format attribute");
5204             break;
5205           case ic_init:
5206             warning_at (location, OPT_Wmissing_format_attribute,
5207                         "initialization left-hand side might be "
5208                         "a candidate for a format attribute");
5209             break;
5210           case ic_return:
5211             warning_at (location, OPT_Wmissing_format_attribute,
5212                         "return type might be "
5213                         "a candidate for a format attribute");
5214             break;
5215           default:
5216             gcc_unreachable ();
5217           }
5218         }
5219
5220       /* Any non-function converts to a [const][volatile] void *
5221          and vice versa; otherwise, targets must be the same.
5222          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
5223       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5224           || (target_cmp = comp_target_types (location, type, rhstype))
5225           || is_opaque_pointer
5226           || (c_common_unsigned_type (mvl)
5227               == c_common_unsigned_type (mvr)))
5228         {
5229           if (pedantic
5230               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
5231                   ||
5232                   (VOID_TYPE_P (ttr)
5233                    && !null_pointer_constant
5234                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
5235             WARN_FOR_ASSIGNMENT (location, OPT_pedantic,
5236                                  G_("ISO C forbids passing argument %d of "
5237                                     "%qE between function pointer "
5238                                     "and %<void *%>"),
5239                                  G_("ISO C forbids assignment between "
5240                                     "function pointer and %<void *%>"),
5241                                  G_("ISO C forbids initialization between "
5242                                     "function pointer and %<void *%>"),
5243                                  G_("ISO C forbids return between function "
5244                                     "pointer and %<void *%>"));
5245           /* Const and volatile mean something different for function types,
5246              so the usual warnings are not appropriate.  */
5247           else if (TREE_CODE (ttr) != FUNCTION_TYPE
5248                    && TREE_CODE (ttl) != FUNCTION_TYPE)
5249             {
5250               if (TYPE_QUALS_NO_ADDR_SPACE (ttr)
5251                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttl))
5252                 {
5253                   /* Types differing only by the presence of the 'volatile'
5254                      qualifier are acceptable if the 'volatile' has been added
5255                      in by the Objective-C EH machinery.  */
5256                   if (!objc_type_quals_match (ttl, ttr))
5257                     WARN_FOR_ASSIGNMENT (location, 0,
5258                                          G_("passing argument %d of %qE discards "
5259                                             "qualifiers from pointer target type"),
5260                                          G_("assignment discards qualifiers "
5261                                             "from pointer target type"),
5262                                          G_("initialization discards qualifiers "
5263                                             "from pointer target type"),
5264                                          G_("return discards qualifiers from "
5265                                             "pointer target type"));
5266                 }
5267               /* If this is not a case of ignoring a mismatch in signedness,
5268                  no warning.  */
5269               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
5270                        || target_cmp)
5271                 ;
5272               /* If there is a mismatch, do warn.  */
5273               else if (warn_pointer_sign)
5274                 WARN_FOR_ASSIGNMENT (location, OPT_Wpointer_sign,
5275                                      G_("pointer targets in passing argument "
5276                                         "%d of %qE differ in signedness"),
5277                                      G_("pointer targets in assignment "
5278                                         "differ in signedness"),
5279                                      G_("pointer targets in initialization "
5280                                         "differ in signedness"),
5281                                      G_("pointer targets in return differ "
5282                                         "in signedness"));
5283             }
5284           else if (TREE_CODE (ttl) == FUNCTION_TYPE
5285                    && TREE_CODE (ttr) == FUNCTION_TYPE)
5286             {
5287               /* Because const and volatile on functions are restrictions
5288                  that say the function will not do certain things,
5289                  it is okay to use a const or volatile function
5290                  where an ordinary one is wanted, but not vice-versa.  */
5291               if (TYPE_QUALS_NO_ADDR_SPACE (ttl)
5292                   & ~TYPE_QUALS_NO_ADDR_SPACE (ttr))
5293                 WARN_FOR_ASSIGNMENT (location, 0,
5294                                      G_("passing argument %d of %qE makes "
5295                                         "qualified function pointer "
5296                                         "from unqualified"),
5297                                      G_("assignment makes qualified function "
5298                                         "pointer from unqualified"),
5299                                      G_("initialization makes qualified "
5300                                         "function pointer from unqualified"),
5301                                      G_("return makes qualified function "
5302                                         "pointer from unqualified"));
5303             }
5304         }
5305       else
5306         /* Avoid warning about the volatile ObjC EH puts on decls.  */
5307         if (!objc_ok)
5308           WARN_FOR_ASSIGNMENT (location, 0,
5309                                G_("passing argument %d of %qE from "
5310                                   "incompatible pointer type"),
5311                                G_("assignment from incompatible pointer type"),
5312                                G_("initialization from incompatible "
5313                                   "pointer type"),
5314                                G_("return from incompatible pointer type"));
5315
5316       return convert (type, rhs);
5317     }
5318   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
5319     {
5320       /* ??? This should not be an error when inlining calls to
5321          unprototyped functions.  */
5322       error_at (location, "invalid use of non-lvalue array");
5323       return error_mark_node;
5324     }
5325   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
5326     {
5327       /* An explicit constant 0 can convert to a pointer,
5328          or one that results from arithmetic, even including
5329          a cast to integer type.  */
5330       if (!null_pointer_constant)
5331         WARN_FOR_ASSIGNMENT (location, 0,
5332                              G_("passing argument %d of %qE makes "
5333                                 "pointer from integer without a cast"),
5334                              G_("assignment makes pointer from integer "
5335                                 "without a cast"),
5336                              G_("initialization makes pointer from "
5337                                 "integer without a cast"),
5338                              G_("return makes pointer from integer "
5339                                 "without a cast"));
5340
5341       return convert (type, rhs);
5342     }
5343   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
5344     {
5345       WARN_FOR_ASSIGNMENT (location, 0,
5346                            G_("passing argument %d of %qE makes integer "
5347                               "from pointer without a cast"),
5348                            G_("assignment makes integer from pointer "
5349                               "without a cast"),
5350                            G_("initialization makes integer from pointer "
5351                               "without a cast"),
5352                            G_("return makes integer from pointer "
5353                               "without a cast"));
5354       return convert (type, rhs);
5355     }
5356   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
5357     {
5358       tree ret;
5359       bool save = in_late_binary_op;
5360       in_late_binary_op = true;
5361       ret = convert (type, rhs);
5362       in_late_binary_op = save;
5363       return ret;
5364     }
5365
5366   switch (errtype)
5367     {
5368     case ic_argpass:
5369       error_at (location, "incompatible type for argument %d of %qE", parmnum, rname);
5370       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
5371               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
5372               "expected %qT but argument is of type %qT", type, rhstype);
5373       break;
5374     case ic_assign:
5375       error_at (location, "incompatible types when assigning to type %qT from "
5376                 "type %qT", type, rhstype);
5377       break;
5378     case ic_init:
5379       error_at (location,
5380                 "incompatible types when initializing type %qT using type %qT",
5381                 type, rhstype);
5382       break;
5383     case ic_return:
5384       error_at (location,
5385                 "incompatible types when returning type %qT but %qT was "
5386                 "expected", rhstype, type);
5387       break;
5388     default:
5389       gcc_unreachable ();
5390     }
5391
5392   return error_mark_node;
5393 }
5394 \f
5395 /* If VALUE is a compound expr all of whose expressions are constant, then
5396    return its value.  Otherwise, return error_mark_node.
5397
5398    This is for handling COMPOUND_EXPRs as initializer elements
5399    which is allowed with a warning when -pedantic is specified.  */
5400
5401 static tree
5402 valid_compound_expr_initializer (tree value, tree endtype)
5403 {
5404   if (TREE_CODE (value) == COMPOUND_EXPR)
5405     {
5406       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
5407           == error_mark_node)
5408         return error_mark_node;
5409       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
5410                                               endtype);
5411     }
5412   else if (!initializer_constant_valid_p (value, endtype))
5413     return error_mark_node;
5414   else
5415     return value;
5416 }
5417 \f
5418 /* Perform appropriate conversions on the initial value of a variable,
5419    store it in the declaration DECL,
5420    and print any error messages that are appropriate.
5421    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5422    If the init is invalid, store an ERROR_MARK.
5423
5424    INIT_LOC is the location of the initial value.  */
5425
5426 void
5427 store_init_value (location_t init_loc, tree decl, tree init, tree origtype)
5428 {
5429   tree value, type;
5430   bool npc = false;
5431
5432   /* If variable's type was invalidly declared, just ignore it.  */
5433
5434   type = TREE_TYPE (decl);
5435   if (TREE_CODE (type) == ERROR_MARK)
5436     return;
5437
5438   /* Digest the specified initializer into an expression.  */
5439
5440   if (init)
5441     npc = null_pointer_constant_p (init);
5442   value = digest_init (init_loc, type, init, origtype, npc,
5443                        true, TREE_STATIC (decl));
5444
5445   /* Store the expression if valid; else report error.  */
5446
5447   if (!in_system_header
5448       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
5449     warning (OPT_Wtraditional, "traditional C rejects automatic "
5450              "aggregate initialization");
5451
5452   DECL_INITIAL (decl) = value;
5453
5454   /* ANSI wants warnings about out-of-range constant initializers.  */
5455   STRIP_TYPE_NOPS (value);
5456   if (TREE_STATIC (decl))
5457     constant_expression_warning (value);
5458
5459   /* Check if we need to set array size from compound literal size.  */
5460   if (TREE_CODE (type) == ARRAY_TYPE
5461       && TYPE_DOMAIN (type) == 0
5462       && value != error_mark_node)
5463     {
5464       tree inside_init = init;
5465
5466       STRIP_TYPE_NOPS (inside_init);
5467       inside_init = fold (inside_init);
5468
5469       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5470         {
5471           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5472
5473           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
5474             {
5475               /* For int foo[] = (int [3]){1}; we need to set array size
5476                  now since later on array initializer will be just the
5477                  brace enclosed list of the compound literal.  */
5478               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5479               TREE_TYPE (decl) = type;
5480               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
5481               layout_type (type);
5482               layout_decl (cldecl, 0);
5483             }
5484         }
5485     }
5486 }
5487 \f
5488 /* Methods for storing and printing names for error messages.  */
5489
5490 /* Implement a spelling stack that allows components of a name to be pushed
5491    and popped.  Each element on the stack is this structure.  */
5492
5493 struct spelling
5494 {
5495   int kind;
5496   union
5497     {
5498       unsigned HOST_WIDE_INT i;
5499       const char *s;
5500     } u;
5501 };
5502
5503 #define SPELLING_STRING 1
5504 #define SPELLING_MEMBER 2
5505 #define SPELLING_BOUNDS 3
5506
5507 static struct spelling *spelling;       /* Next stack element (unused).  */
5508 static struct spelling *spelling_base;  /* Spelling stack base.  */
5509 static int spelling_size;               /* Size of the spelling stack.  */
5510
5511 /* Macros to save and restore the spelling stack around push_... functions.
5512    Alternative to SAVE_SPELLING_STACK.  */
5513
5514 #define SPELLING_DEPTH() (spelling - spelling_base)
5515 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
5516
5517 /* Push an element on the spelling stack with type KIND and assign VALUE
5518    to MEMBER.  */
5519
5520 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
5521 {                                                                       \
5522   int depth = SPELLING_DEPTH ();                                        \
5523                                                                         \
5524   if (depth >= spelling_size)                                           \
5525     {                                                                   \
5526       spelling_size += 10;                                              \
5527       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
5528                                   spelling_size);                       \
5529       RESTORE_SPELLING_DEPTH (depth);                                   \
5530     }                                                                   \
5531                                                                         \
5532   spelling->kind = (KIND);                                              \
5533   spelling->MEMBER = (VALUE);                                           \
5534   spelling++;                                                           \
5535 }
5536
5537 /* Push STRING on the stack.  Printed literally.  */
5538
5539 static void
5540 push_string (const char *string)
5541 {
5542   PUSH_SPELLING (SPELLING_STRING, string, u.s);
5543 }
5544
5545 /* Push a member name on the stack.  Printed as '.' STRING.  */
5546
5547 static void
5548 push_member_name (tree decl)
5549 {
5550   const char *const string
5551     = (DECL_NAME (decl)
5552        ? identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)))
5553        : _("<anonymous>"));
5554   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
5555 }
5556
5557 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
5558
5559 static void
5560 push_array_bounds (unsigned HOST_WIDE_INT bounds)
5561 {
5562   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
5563 }
5564
5565 /* Compute the maximum size in bytes of the printed spelling.  */
5566
5567 static int
5568 spelling_length (void)
5569 {
5570   int size = 0;
5571   struct spelling *p;
5572
5573   for (p = spelling_base; p < spelling; p++)
5574     {
5575       if (p->kind == SPELLING_BOUNDS)
5576         size += 25;
5577       else
5578         size += strlen (p->u.s) + 1;
5579     }
5580
5581   return size;
5582 }
5583
5584 /* Print the spelling to BUFFER and return it.  */
5585
5586 static char *
5587 print_spelling (char *buffer)
5588 {
5589   char *d = buffer;
5590   struct spelling *p;
5591
5592   for (p = spelling_base; p < spelling; p++)
5593     if (p->kind == SPELLING_BOUNDS)
5594       {
5595         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
5596         d += strlen (d);
5597       }
5598     else
5599       {
5600         const char *s;
5601         if (p->kind == SPELLING_MEMBER)
5602           *d++ = '.';
5603         for (s = p->u.s; (*d = *s++); d++)
5604           ;
5605       }
5606   *d++ = '\0';
5607   return buffer;
5608 }
5609
5610 /* Issue an error message for a bad initializer component.
5611    MSGID identifies the message.
5612    The component name is taken from the spelling stack.  */
5613
5614 void
5615 error_init (const char *msgid)
5616 {
5617   char *ofwhat;
5618
5619   error ("%s", _(msgid));
5620   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5621   if (*ofwhat)
5622     error ("(near initialization for %qs)", ofwhat);
5623 }
5624
5625 /* Issue a pedantic warning for a bad initializer component.  OPT is
5626    the option OPT_* (from options.h) controlling this warning or 0 if
5627    it is unconditionally given.  MSGID identifies the message.  The
5628    component name is taken from the spelling stack.  */
5629
5630 void
5631 pedwarn_init (location_t location, int opt, const char *msgid)
5632 {
5633   char *ofwhat;
5634
5635   pedwarn (location, opt, "%s", _(msgid));
5636   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5637   if (*ofwhat)
5638     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
5639 }
5640
5641 /* Issue a warning for a bad initializer component.
5642
5643    OPT is the OPT_W* value corresponding to the warning option that
5644    controls this warning.  MSGID identifies the message.  The
5645    component name is taken from the spelling stack.  */
5646
5647 static void
5648 warning_init (int opt, const char *msgid)
5649 {
5650   char *ofwhat;
5651
5652   warning (opt, "%s", _(msgid));
5653   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
5654   if (*ofwhat)
5655     warning (opt, "(near initialization for %qs)", ofwhat);
5656 }
5657 \f
5658 /* If TYPE is an array type and EXPR is a parenthesized string
5659    constant, warn if pedantic that EXPR is being used to initialize an
5660    object of type TYPE.  */
5661
5662 void
5663 maybe_warn_string_init (tree type, struct c_expr expr)
5664 {
5665   if (pedantic
5666       && TREE_CODE (type) == ARRAY_TYPE
5667       && TREE_CODE (expr.value) == STRING_CST
5668       && expr.original_code != STRING_CST)
5669     pedwarn_init (input_location, OPT_pedantic,
5670                   "array initialized from parenthesized string constant");
5671 }
5672
5673 /* Digest the parser output INIT as an initializer for type TYPE.
5674    Return a C expression of type TYPE to represent the initial value.
5675
5676    If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
5677
5678    NULL_POINTER_CONSTANT is true if INIT is a null pointer constant.
5679
5680    If INIT is a string constant, STRICT_STRING is true if it is
5681    unparenthesized or we should not warn here for it being parenthesized.
5682    For other types of INIT, STRICT_STRING is not used.
5683
5684    INIT_LOC is the location of the INIT.
5685
5686    REQUIRE_CONSTANT requests an error if non-constant initializers or
5687    elements are seen.  */
5688
5689 static tree
5690 digest_init (location_t init_loc, tree type, tree init, tree origtype,
5691              bool null_pointer_constant, bool strict_string,
5692              int require_constant)
5693 {
5694   enum tree_code code = TREE_CODE (type);
5695   tree inside_init = init;
5696   tree semantic_type = NULL_TREE;
5697   bool maybe_const = true;
5698
5699   if (type == error_mark_node
5700       || !init
5701       || init == error_mark_node
5702       || TREE_TYPE (init) == error_mark_node)
5703     return error_mark_node;
5704
5705   STRIP_TYPE_NOPS (inside_init);
5706
5707   if (TREE_CODE (inside_init) == EXCESS_PRECISION_EXPR)
5708     {
5709       semantic_type = TREE_TYPE (inside_init);
5710       inside_init = TREE_OPERAND (inside_init, 0);
5711     }
5712   inside_init = c_fully_fold (inside_init, require_constant, &maybe_const);
5713   inside_init = decl_constant_value_for_optimization (inside_init);
5714
5715   /* Initialization of an array of chars from a string constant
5716      optionally enclosed in braces.  */
5717
5718   if (code == ARRAY_TYPE && inside_init
5719       && TREE_CODE (inside_init) == STRING_CST)
5720     {
5721       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
5722       /* Note that an array could be both an array of character type
5723          and an array of wchar_t if wchar_t is signed char or unsigned
5724          char.  */
5725       bool char_array = (typ1 == char_type_node
5726                          || typ1 == signed_char_type_node
5727                          || typ1 == unsigned_char_type_node);
5728       bool wchar_array = !!comptypes (typ1, wchar_type_node);
5729       bool char16_array = !!comptypes (typ1, char16_type_node);
5730       bool char32_array = !!comptypes (typ1, char32_type_node);
5731
5732       if (char_array || wchar_array || char16_array || char32_array)
5733         {
5734           struct c_expr expr;
5735           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
5736           expr.value = inside_init;
5737           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
5738           expr.original_type = NULL;
5739           maybe_warn_string_init (type, expr);
5740
5741           if (TYPE_DOMAIN (type) && !TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
5742             pedwarn_init (init_loc, OPT_pedantic,
5743                           "initialization of a flexible array member");
5744
5745           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5746                          TYPE_MAIN_VARIANT (type)))
5747             return inside_init;
5748
5749           if (char_array)
5750             {
5751               if (typ2 != char_type_node)
5752                 {
5753                   error_init ("char-array initialized from wide string");
5754                   return error_mark_node;
5755                 }
5756             }
5757           else
5758             {
5759               if (typ2 == char_type_node)
5760                 {
5761                   error_init ("wide character array initialized from non-wide "
5762                               "string");
5763                   return error_mark_node;
5764                 }
5765               else if (!comptypes(typ1, typ2))
5766                 {
5767                   error_init ("wide character array initialized from "
5768                               "incompatible wide string");
5769                   return error_mark_node;
5770                 }
5771             }
5772
5773           TREE_TYPE (inside_init) = type;
5774           if (TYPE_DOMAIN (type) != 0
5775               && TYPE_SIZE (type) != 0
5776               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
5777             {
5778               unsigned HOST_WIDE_INT len = TREE_STRING_LENGTH (inside_init);
5779
5780               /* Subtract the size of a single (possibly wide) character
5781                  because it's ok to ignore the terminating null char
5782                  that is counted in the length of the constant.  */
5783               if (0 > compare_tree_int (TYPE_SIZE_UNIT (type),
5784                                         (len
5785                                          - (TYPE_PRECISION (typ1)
5786                                             / BITS_PER_UNIT))))
5787                 pedwarn_init (init_loc, 0,
5788                               ("initializer-string for array of chars "
5789                                "is too long"));
5790               else if (warn_cxx_compat
5791                        && 0 > compare_tree_int (TYPE_SIZE_UNIT (type), len))
5792                 warning_at (init_loc, OPT_Wc___compat,
5793                             ("initializer-string for array chars "
5794                              "is too long for C++"));
5795             }
5796
5797           return inside_init;
5798         }
5799       else if (INTEGRAL_TYPE_P (typ1))
5800         {
5801           error_init ("array of inappropriate type initialized "
5802                       "from string constant");
5803           return error_mark_node;
5804         }
5805     }
5806
5807   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
5808      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
5809      below and handle as a constructor.  */
5810   if (code == VECTOR_TYPE
5811       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
5812       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
5813       && TREE_CONSTANT (inside_init))
5814     {
5815       if (TREE_CODE (inside_init) == VECTOR_CST
5816           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5817                         TYPE_MAIN_VARIANT (type)))
5818         return inside_init;
5819
5820       if (TREE_CODE (inside_init) == CONSTRUCTOR)
5821         {
5822           unsigned HOST_WIDE_INT ix;
5823           tree value;
5824           bool constant_p = true;
5825
5826           /* Iterate through elements and check if all constructor
5827              elements are *_CSTs.  */
5828           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
5829             if (!CONSTANT_CLASS_P (value))
5830               {
5831                 constant_p = false;
5832                 break;
5833               }
5834
5835           if (constant_p)
5836             return build_vector_from_ctor (type,
5837                                            CONSTRUCTOR_ELTS (inside_init));
5838         }
5839     }
5840
5841   if (warn_sequence_point)
5842     verify_sequence_points (inside_init);
5843
5844   /* Any type can be initialized
5845      from an expression of the same type, optionally with braces.  */
5846
5847   if (inside_init && TREE_TYPE (inside_init) != 0
5848       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
5849                      TYPE_MAIN_VARIANT (type))
5850           || (code == ARRAY_TYPE
5851               && comptypes (TREE_TYPE (inside_init), type))
5852           || (code == VECTOR_TYPE
5853               && comptypes (TREE_TYPE (inside_init), type))
5854           || (code == POINTER_TYPE
5855               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
5856               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
5857                             TREE_TYPE (type)))))
5858     {
5859       if (code == POINTER_TYPE)
5860         {
5861           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
5862             {
5863               if (TREE_CODE (inside_init) == STRING_CST
5864                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5865                 inside_init = array_to_pointer_conversion
5866                   (init_loc, inside_init);
5867               else
5868                 {
5869                   error_init ("invalid use of non-lvalue array");
5870                   return error_mark_node;
5871                 }
5872             }
5873         }
5874
5875       if (code == VECTOR_TYPE)
5876         /* Although the types are compatible, we may require a
5877            conversion.  */
5878         inside_init = convert (type, inside_init);
5879
5880       if (require_constant
5881           && (code == VECTOR_TYPE || !flag_isoc99)
5882           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
5883         {
5884           /* As an extension, allow initializing objects with static storage
5885              duration with compound literals (which are then treated just as
5886              the brace enclosed list they contain).  Also allow this for
5887              vectors, as we can only assign them with compound literals.  */
5888           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
5889           inside_init = DECL_INITIAL (decl);
5890         }
5891
5892       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
5893           && TREE_CODE (inside_init) != CONSTRUCTOR)
5894         {
5895           error_init ("array initialized from non-constant array expression");
5896           return error_mark_node;
5897         }
5898
5899       /* Compound expressions can only occur here if -pedantic or
5900          -pedantic-errors is specified.  In the later case, we always want
5901          an error.  In the former case, we simply want a warning.  */
5902       if (require_constant && pedantic
5903           && TREE_CODE (inside_init) == COMPOUND_EXPR)
5904         {
5905           inside_init
5906             = valid_compound_expr_initializer (inside_init,
5907                                                TREE_TYPE (inside_init));
5908           if (inside_init == error_mark_node)
5909             error_init ("initializer element is not constant");
5910           else
5911             pedwarn_init (init_loc, OPT_pedantic,
5912                           "initializer element is not constant");
5913           if (flag_pedantic_errors)
5914             inside_init = error_mark_node;
5915         }
5916       else if (require_constant
5917                && !initializer_constant_valid_p (inside_init,
5918                                                  TREE_TYPE (inside_init)))
5919         {
5920           error_init ("initializer element is not constant");
5921           inside_init = error_mark_node;
5922         }
5923       else if (require_constant && !maybe_const)
5924         pedwarn_init (init_loc, 0,
5925                       "initializer element is not a constant expression");
5926
5927       /* Added to enable additional -Wmissing-format-attribute warnings.  */
5928       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
5929         inside_init = convert_for_assignment (init_loc, type, inside_init,
5930                                               origtype,
5931                                               ic_init, null_pointer_constant,
5932                                               NULL_TREE, NULL_TREE, 0);
5933       return inside_init;
5934     }
5935
5936   /* Handle scalar types, including conversions.  */
5937
5938   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
5939       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
5940       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
5941     {
5942       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
5943           && (TREE_CODE (init) == STRING_CST
5944               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
5945         inside_init = init = array_to_pointer_conversion (init_loc, init);
5946       if (semantic_type)
5947         inside_init = build1 (EXCESS_PRECISION_EXPR, semantic_type,
5948                               inside_init);
5949       inside_init
5950         = convert_for_assignment (init_loc, type, inside_init, origtype,
5951                                   ic_init, null_pointer_constant,
5952                                   NULL_TREE, NULL_TREE, 0);
5953
5954       /* Check to see if we have already given an error message.  */
5955       if (inside_init == error_mark_node)
5956         ;
5957       else if (require_constant && !TREE_CONSTANT (inside_init))
5958         {
5959           error_init ("initializer element is not constant");
5960           inside_init = error_mark_node;
5961         }
5962       else if (require_constant
5963                && !initializer_constant_valid_p (inside_init,
5964                                                  TREE_TYPE (inside_init)))
5965         {
5966           error_init ("initializer element is not computable at load time");
5967           inside_init = error_mark_node;
5968         }
5969       else if (require_constant && !maybe_const)
5970         pedwarn_init (init_loc, 0,
5971                       "initializer element is not a constant expression");
5972
5973       return inside_init;
5974     }
5975
5976   /* Come here only for records and arrays.  */
5977
5978   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5979     {
5980       error_init ("variable-sized object may not be initialized");
5981       return error_mark_node;
5982     }
5983
5984   error_init ("invalid initializer");
5985   return error_mark_node;
5986 }
5987 \f
5988 /* Handle initializers that use braces.  */
5989
5990 /* Type of object we are accumulating a constructor for.
5991    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5992 static tree constructor_type;
5993
5994 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5995    left to fill.  */
5996 static tree constructor_fields;
5997
5998 /* For an ARRAY_TYPE, this is the specified index
5999    at which to store the next element we get.  */
6000 static tree constructor_index;
6001
6002 /* For an ARRAY_TYPE, this is the maximum index.  */
6003 static tree constructor_max_index;
6004
6005 /* For a RECORD_TYPE, this is the first field not yet written out.  */
6006 static tree constructor_unfilled_fields;
6007
6008 /* For an ARRAY_TYPE, this is the index of the first element
6009    not yet written out.  */
6010 static tree constructor_unfilled_index;
6011
6012 /* In a RECORD_TYPE, the byte index of the next consecutive field.
6013    This is so we can generate gaps between fields, when appropriate.  */
6014 static tree constructor_bit_index;
6015
6016 /* If we are saving up the elements rather than allocating them,
6017    this is the list of elements so far (in reverse order,
6018    most recent first).  */
6019 static VEC(constructor_elt,gc) *constructor_elements;
6020
6021 /* 1 if constructor should be incrementally stored into a constructor chain,
6022    0 if all the elements should be kept in AVL tree.  */
6023 static int constructor_incremental;
6024
6025 /* 1 if so far this constructor's elements are all compile-time constants.  */
6026 static int constructor_constant;
6027
6028 /* 1 if so far this constructor's elements are all valid address constants.  */
6029 static int constructor_simple;
6030
6031 /* 1 if this constructor has an element that cannot be part of a
6032    constant expression.  */
6033 static int constructor_nonconst;
6034
6035 /* 1 if this constructor is erroneous so far.  */
6036 static int constructor_erroneous;
6037
6038 /* Structure for managing pending initializer elements, organized as an
6039    AVL tree.  */
6040
6041 struct init_node
6042 {
6043   struct init_node *left, *right;
6044   struct init_node *parent;
6045   int balance;
6046   tree purpose;
6047   tree value;
6048   tree origtype;
6049 };
6050
6051 /* Tree of pending elements at this constructor level.
6052    These are elements encountered out of order
6053    which belong at places we haven't reached yet in actually
6054    writing the output.
6055    Will never hold tree nodes across GC runs.  */
6056 static struct init_node *constructor_pending_elts;
6057
6058 /* The SPELLING_DEPTH of this constructor.  */
6059 static int constructor_depth;
6060
6061 /* DECL node for which an initializer is being read.
6062    0 means we are reading a constructor expression
6063    such as (struct foo) {...}.  */
6064 static tree constructor_decl;
6065
6066 /* Nonzero if this is an initializer for a top-level decl.  */
6067 static int constructor_top_level;
6068
6069 /* Nonzero if there were any member designators in this initializer.  */
6070 static int constructor_designated;
6071
6072 /* Nesting depth of designator list.  */
6073 static int designator_depth;
6074
6075 /* Nonzero if there were diagnosed errors in this designator list.  */
6076 static int designator_erroneous;
6077
6078 \f
6079 /* This stack has a level for each implicit or explicit level of
6080    structuring in the initializer, including the outermost one.  It
6081    saves the values of most of the variables above.  */
6082
6083 struct constructor_range_stack;
6084
6085 struct constructor_stack
6086 {
6087   struct constructor_stack *next;
6088   tree type;
6089   tree fields;
6090   tree index;
6091   tree max_index;
6092   tree unfilled_index;
6093   tree unfilled_fields;
6094   tree bit_index;
6095   VEC(constructor_elt,gc) *elements;
6096   struct init_node *pending_elts;
6097   int offset;
6098   int depth;
6099   /* If value nonzero, this value should replace the entire
6100      constructor at this level.  */
6101   struct c_expr replacement_value;
6102   struct constructor_range_stack *range_stack;
6103   char constant;
6104   char simple;
6105   char nonconst;
6106   char implicit;
6107   char erroneous;
6108   char outer;
6109   char incremental;
6110   char designated;
6111 };
6112
6113 static struct constructor_stack *constructor_stack;
6114
6115 /* This stack represents designators from some range designator up to
6116    the last designator in the list.  */
6117
6118 struct constructor_range_stack
6119 {
6120   struct constructor_range_stack *next, *prev;
6121   struct constructor_stack *stack;
6122   tree range_start;
6123   tree index;
6124   tree range_end;
6125   tree fields;
6126 };
6127
6128 static struct constructor_range_stack *constructor_range_stack;
6129
6130 /* This stack records separate initializers that are nested.
6131    Nested initializers can't happen in ANSI C, but GNU C allows them
6132    in cases like { ... (struct foo) { ... } ... }.  */
6133
6134 struct initializer_stack
6135 {
6136   struct initializer_stack *next;
6137   tree decl;
6138   struct constructor_stack *constructor_stack;
6139   struct constructor_range_stack *constructor_range_stack;
6140   VEC(constructor_elt,gc) *elements;
6141   struct spelling *spelling;
6142   struct spelling *spelling_base;
6143   int spelling_size;
6144   char top_level;
6145   char require_constant_value;
6146   char require_constant_elements;
6147 };
6148
6149 static struct initializer_stack *initializer_stack;
6150 \f
6151 /* Prepare to parse and output the initializer for variable DECL.  */
6152
6153 void
6154 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
6155 {
6156   const char *locus;
6157   struct initializer_stack *p = XNEW (struct initializer_stack);
6158
6159   p->decl = constructor_decl;
6160   p->require_constant_value = require_constant_value;
6161   p->require_constant_elements = require_constant_elements;
6162   p->constructor_stack = constructor_stack;
6163   p->constructor_range_stack = constructor_range_stack;
6164   p->elements = constructor_elements;
6165   p->spelling = spelling;
6166   p->spelling_base = spelling_base;
6167   p->spelling_size = spelling_size;
6168   p->top_level = constructor_top_level;
6169   p->next = initializer_stack;
6170   initializer_stack = p;
6171
6172   constructor_decl = decl;
6173   constructor_designated = 0;
6174   constructor_top_level = top_level;
6175
6176   if (decl != 0 && decl != error_mark_node)
6177     {
6178       require_constant_value = TREE_STATIC (decl);
6179       require_constant_elements
6180         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
6181            /* For a scalar, you can always use any value to initialize,
6182               even within braces.  */
6183            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
6184                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
6185                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
6186                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
6187       locus = identifier_to_locale (IDENTIFIER_POINTER (DECL_NAME (decl)));
6188     }
6189   else
6190     {
6191       require_constant_value = 0;
6192       require_constant_elements = 0;
6193       locus = _("(anonymous)");
6194     }
6195
6196   constructor_stack = 0;
6197   constructor_range_stack = 0;
6198
6199   missing_braces_mentioned = 0;
6200
6201   spelling_base = 0;
6202   spelling_size = 0;
6203   RESTORE_SPELLING_DEPTH (0);
6204
6205   if (locus)
6206     push_string (locus);
6207 }
6208
6209 void
6210 finish_init (void)
6211 {
6212   struct initializer_stack *p = initializer_stack;
6213
6214   /* Free the whole constructor stack of this initializer.  */
6215   while (constructor_stack)
6216     {
6217       struct constructor_stack *q = constructor_stack;
6218       constructor_stack = q->next;
6219       free (q);
6220     }
6221
6222   gcc_assert (!constructor_range_stack);
6223
6224   /* Pop back to the data of the outer initializer (if any).  */
6225   free (spelling_base);
6226
6227   constructor_decl = p->decl;
6228   require_constant_value = p->require_constant_value;
6229   require_constant_elements = p->require_constant_elements;
6230   constructor_stack = p->constructor_stack;
6231   constructor_range_stack = p->constructor_range_stack;
6232   constructor_elements = p->elements;
6233   spelling = p->spelling;
6234   spelling_base = p->spelling_base;
6235   spelling_size = p->spelling_size;
6236   constructor_top_level = p->top_level;
6237   initializer_stack = p->next;
6238   free (p);
6239 }
6240 \f
6241 /* Call here when we see the initializer is surrounded by braces.
6242    This is instead of a call to push_init_level;
6243    it is matched by a call to pop_init_level.
6244
6245    TYPE is the type to initialize, for a constructor expression.
6246    For an initializer for a decl, TYPE is zero.  */
6247
6248 void
6249 really_start_incremental_init (tree type)
6250 {
6251   struct constructor_stack *p = XNEW (struct constructor_stack);
6252
6253   if (type == 0)
6254     type = TREE_TYPE (constructor_decl);
6255
6256   if (TREE_CODE (type) == VECTOR_TYPE
6257       && TYPE_VECTOR_OPAQUE (type))
6258     error ("opaque vector types cannot be initialized");
6259
6260   p->type = constructor_type;
6261   p->fields = constructor_fields;
6262   p->index = constructor_index;
6263   p->max_index = constructor_max_index;
6264   p->unfilled_index = constructor_unfilled_index;
6265   p->unfilled_fields = constructor_unfilled_fields;
6266   p->bit_index = constructor_bit_index;
6267   p->elements = constructor_elements;
6268   p->constant = constructor_constant;
6269   p->simple = constructor_simple;
6270   p->nonconst = constructor_nonconst;
6271   p->erroneous = constructor_erroneous;
6272   p->pending_elts = constructor_pending_elts;
6273   p->depth = constructor_depth;
6274   p->replacement_value.value = 0;
6275   p->replacement_value.original_code = ERROR_MARK;
6276   p->replacement_value.original_type = NULL;
6277   p->implicit = 0;
6278   p->range_stack = 0;
6279   p->outer = 0;
6280   p->incremental = constructor_incremental;
6281   p->designated = constructor_designated;
6282   p->next = 0;
6283   constructor_stack = p;
6284
6285   constructor_constant = 1;
6286   constructor_simple = 1;
6287   constructor_nonconst = 0;
6288   constructor_depth = SPELLING_DEPTH ();
6289   constructor_elements = 0;
6290   constructor_pending_elts = 0;
6291   constructor_type = type;
6292   constructor_incremental = 1;
6293   constructor_designated = 0;
6294   designator_depth = 0;
6295   designator_erroneous = 0;
6296
6297   if (TREE_CODE (constructor_type) == RECORD_TYPE
6298       || TREE_CODE (constructor_type) == UNION_TYPE)
6299     {
6300       constructor_fields = TYPE_FIELDS (constructor_type);
6301       /* Skip any nameless bit fields at the beginning.  */
6302       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6303              && DECL_NAME (constructor_fields) == 0)
6304         constructor_fields = TREE_CHAIN (constructor_fields);
6305
6306       constructor_unfilled_fields = constructor_fields;
6307       constructor_bit_index = bitsize_zero_node;
6308     }
6309   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6310     {
6311       if (TYPE_DOMAIN (constructor_type))
6312         {
6313           constructor_max_index
6314             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6315
6316           /* Detect non-empty initializations of zero-length arrays.  */
6317           if (constructor_max_index == NULL_TREE
6318               && TYPE_SIZE (constructor_type))
6319             constructor_max_index = build_int_cst (NULL_TREE, -1);
6320
6321           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6322              to initialize VLAs will cause a proper error; avoid tree
6323              checking errors as well by setting a safe value.  */
6324           if (constructor_max_index
6325               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6326             constructor_max_index = build_int_cst (NULL_TREE, -1);
6327
6328           constructor_index
6329             = convert (bitsizetype,
6330                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6331         }
6332       else
6333         {
6334           constructor_index = bitsize_zero_node;
6335           constructor_max_index = NULL_TREE;
6336         }
6337
6338       constructor_unfilled_index = constructor_index;
6339     }
6340   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6341     {
6342       /* Vectors are like simple fixed-size arrays.  */
6343       constructor_max_index =
6344         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6345       constructor_index = bitsize_zero_node;
6346       constructor_unfilled_index = constructor_index;
6347     }
6348   else
6349     {
6350       /* Handle the case of int x = {5}; */
6351       constructor_fields = constructor_type;
6352       constructor_unfilled_fields = constructor_type;
6353     }
6354 }
6355 \f
6356 /* Push down into a subobject, for initialization.
6357    If this is for an explicit set of braces, IMPLICIT is 0.
6358    If it is because the next element belongs at a lower level,
6359    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
6360
6361 void
6362 push_init_level (int implicit)
6363 {
6364   struct constructor_stack *p;
6365   tree value = NULL_TREE;
6366
6367   /* If we've exhausted any levels that didn't have braces,
6368      pop them now.  If implicit == 1, this will have been done in
6369      process_init_element; do not repeat it here because in the case
6370      of excess initializers for an empty aggregate this leads to an
6371      infinite cycle of popping a level and immediately recreating
6372      it.  */
6373   if (implicit != 1)
6374     {
6375       while (constructor_stack->implicit)
6376         {
6377           if ((TREE_CODE (constructor_type) == RECORD_TYPE
6378                || TREE_CODE (constructor_type) == UNION_TYPE)
6379               && constructor_fields == 0)
6380             process_init_element (pop_init_level (1), true);
6381           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6382                    && constructor_max_index
6383                    && tree_int_cst_lt (constructor_max_index,
6384                                        constructor_index))
6385             process_init_element (pop_init_level (1), true);
6386           else
6387             break;
6388         }
6389     }
6390
6391   /* Unless this is an explicit brace, we need to preserve previous
6392      content if any.  */
6393   if (implicit)
6394     {
6395       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6396            || TREE_CODE (constructor_type) == UNION_TYPE)
6397           && constructor_fields)
6398         value = find_init_member (constructor_fields);
6399       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6400         value = find_init_member (constructor_index);
6401     }
6402
6403   p = XNEW (struct constructor_stack);
6404   p->type = constructor_type;
6405   p->fields = constructor_fields;
6406   p->index = constructor_index;
6407   p->max_index = constructor_max_index;
6408   p->unfilled_index = constructor_unfilled_index;
6409   p->unfilled_fields = constructor_unfilled_fields;
6410   p->bit_index = constructor_bit_index;
6411   p->elements = constructor_elements;
6412   p->constant = constructor_constant;
6413   p->simple = constructor_simple;
6414   p->nonconst = constructor_nonconst;
6415   p->erroneous = constructor_erroneous;
6416   p->pending_elts = constructor_pending_elts;
6417   p->depth = constructor_depth;
6418   p->replacement_value.value = 0;
6419   p->replacement_value.original_code = ERROR_MARK;
6420   p->replacement_value.original_type = NULL;
6421   p->implicit = implicit;
6422   p->outer = 0;
6423   p->incremental = constructor_incremental;
6424   p->designated = constructor_designated;
6425   p->next = constructor_stack;
6426   p->range_stack = 0;
6427   constructor_stack = p;
6428
6429   constructor_constant = 1;
6430   constructor_simple = 1;
6431   constructor_nonconst = 0;
6432   constructor_depth = SPELLING_DEPTH ();
6433   constructor_elements = 0;
6434   constructor_incremental = 1;
6435   constructor_designated = 0;
6436   constructor_pending_elts = 0;
6437   if (!implicit)
6438     {
6439       p->range_stack = constructor_range_stack;
6440       constructor_range_stack = 0;
6441       designator_depth = 0;
6442       designator_erroneous = 0;
6443     }
6444
6445   /* Don't die if an entire brace-pair level is superfluous
6446      in the containing level.  */
6447   if (constructor_type == 0)
6448     ;
6449   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6450            || TREE_CODE (constructor_type) == UNION_TYPE)
6451     {
6452       /* Don't die if there are extra init elts at the end.  */
6453       if (constructor_fields == 0)
6454         constructor_type = 0;
6455       else
6456         {
6457           constructor_type = TREE_TYPE (constructor_fields);
6458           push_member_name (constructor_fields);
6459           constructor_depth++;
6460         }
6461     }
6462   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6463     {
6464       constructor_type = TREE_TYPE (constructor_type);
6465       push_array_bounds (tree_low_cst (constructor_index, 1));
6466       constructor_depth++;
6467     }
6468
6469   if (constructor_type == 0)
6470     {
6471       error_init ("extra brace group at end of initializer");
6472       constructor_fields = 0;
6473       constructor_unfilled_fields = 0;
6474       return;
6475     }
6476
6477   if (value && TREE_CODE (value) == CONSTRUCTOR)
6478     {
6479       constructor_constant = TREE_CONSTANT (value);
6480       constructor_simple = TREE_STATIC (value);
6481       constructor_nonconst = CONSTRUCTOR_NON_CONST (value);
6482       constructor_elements = CONSTRUCTOR_ELTS (value);
6483       if (!VEC_empty (constructor_elt, constructor_elements)
6484           && (TREE_CODE (constructor_type) == RECORD_TYPE
6485               || TREE_CODE (constructor_type) == ARRAY_TYPE))
6486         set_nonincremental_init ();
6487     }
6488
6489   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
6490     {
6491       missing_braces_mentioned = 1;
6492       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
6493     }
6494
6495   if (TREE_CODE (constructor_type) == RECORD_TYPE
6496            || TREE_CODE (constructor_type) == UNION_TYPE)
6497     {
6498       constructor_fields = TYPE_FIELDS (constructor_type);
6499       /* Skip any nameless bit fields at the beginning.  */
6500       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
6501              && DECL_NAME (constructor_fields) == 0)
6502         constructor_fields = TREE_CHAIN (constructor_fields);
6503
6504       constructor_unfilled_fields = constructor_fields;
6505       constructor_bit_index = bitsize_zero_node;
6506     }
6507   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6508     {
6509       /* Vectors are like simple fixed-size arrays.  */
6510       constructor_max_index =
6511         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
6512       constructor_index = convert (bitsizetype, integer_zero_node);
6513       constructor_unfilled_index = constructor_index;
6514     }
6515   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6516     {
6517       if (TYPE_DOMAIN (constructor_type))
6518         {
6519           constructor_max_index
6520             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
6521
6522           /* Detect non-empty initializations of zero-length arrays.  */
6523           if (constructor_max_index == NULL_TREE
6524               && TYPE_SIZE (constructor_type))
6525             constructor_max_index = build_int_cst (NULL_TREE, -1);
6526
6527           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
6528              to initialize VLAs will cause a proper error; avoid tree
6529              checking errors as well by setting a safe value.  */
6530           if (constructor_max_index
6531               && TREE_CODE (constructor_max_index) != INTEGER_CST)
6532             constructor_max_index = build_int_cst (NULL_TREE, -1);
6533
6534           constructor_index
6535             = convert (bitsizetype,
6536                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6537         }
6538       else
6539         constructor_index = bitsize_zero_node;
6540
6541       constructor_unfilled_index = constructor_index;
6542       if (value && TREE_CODE (value) == STRING_CST)
6543         {
6544           /* We need to split the char/wchar array into individual
6545              characters, so that we don't have to special case it
6546              everywhere.  */
6547           set_nonincremental_init_from_string (value);
6548         }
6549     }
6550   else
6551     {
6552       if (constructor_type != error_mark_node)
6553         warning_init (0, "braces around scalar initializer");
6554       constructor_fields = constructor_type;
6555       constructor_unfilled_fields = constructor_type;
6556     }
6557 }
6558
6559 /* At the end of an implicit or explicit brace level,
6560    finish up that level of constructor.  If a single expression
6561    with redundant braces initialized that level, return the
6562    c_expr structure for that expression.  Otherwise, the original_code
6563    element is set to ERROR_MARK.
6564    If we were outputting the elements as they are read, return 0 as the value
6565    from inner levels (process_init_element ignores that),
6566    but return error_mark_node as the value from the outermost level
6567    (that's what we want to put in DECL_INITIAL).
6568    Otherwise, return a CONSTRUCTOR expression as the value.  */
6569
6570 struct c_expr
6571 pop_init_level (int implicit)
6572 {
6573   struct constructor_stack *p;
6574   struct c_expr ret;
6575   ret.value = 0;
6576   ret.original_code = ERROR_MARK;
6577   ret.original_type = NULL;
6578
6579   if (implicit == 0)
6580     {
6581       /* When we come to an explicit close brace,
6582          pop any inner levels that didn't have explicit braces.  */
6583       while (constructor_stack->implicit)
6584         process_init_element (pop_init_level (1), true);
6585
6586       gcc_assert (!constructor_range_stack);
6587     }
6588
6589   /* Now output all pending elements.  */
6590   constructor_incremental = 1;
6591   output_pending_init_elements (1);
6592
6593   p = constructor_stack;
6594
6595   /* Error for initializing a flexible array member, or a zero-length
6596      array member in an inappropriate context.  */
6597   if (constructor_type && constructor_fields
6598       && TREE_CODE (constructor_type) == ARRAY_TYPE
6599       && TYPE_DOMAIN (constructor_type)
6600       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
6601     {
6602       /* Silently discard empty initializations.  The parser will
6603          already have pedwarned for empty brackets.  */
6604       if (integer_zerop (constructor_unfilled_index))
6605         constructor_type = NULL_TREE;
6606       else
6607         {
6608           gcc_assert (!TYPE_SIZE (constructor_type));
6609
6610           if (constructor_depth > 2)
6611             error_init ("initialization of flexible array member in a nested context");
6612           else
6613             pedwarn_init (input_location, OPT_pedantic,
6614                           "initialization of a flexible array member");
6615
6616           /* We have already issued an error message for the existence
6617              of a flexible array member not at the end of the structure.
6618              Discard the initializer so that we do not die later.  */
6619           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
6620             constructor_type = NULL_TREE;
6621         }
6622     }
6623
6624   /* Warn when some struct elements are implicitly initialized to zero.  */
6625   if (warn_missing_field_initializers
6626       && constructor_type
6627       && TREE_CODE (constructor_type) == RECORD_TYPE
6628       && constructor_unfilled_fields)
6629     {
6630         /* Do not warn for flexible array members or zero-length arrays.  */
6631         while (constructor_unfilled_fields
6632                && (!DECL_SIZE (constructor_unfilled_fields)
6633                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
6634           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6635
6636         /* Do not warn if this level of the initializer uses member
6637            designators; it is likely to be deliberate.  */
6638         if (constructor_unfilled_fields && !constructor_designated)
6639           {
6640             push_member_name (constructor_unfilled_fields);
6641             warning_init (OPT_Wmissing_field_initializers,
6642                           "missing initializer");
6643             RESTORE_SPELLING_DEPTH (constructor_depth);
6644           }
6645     }
6646
6647   /* Pad out the end of the structure.  */
6648   if (p->replacement_value.value)
6649     /* If this closes a superfluous brace pair,
6650        just pass out the element between them.  */
6651     ret = p->replacement_value;
6652   else if (constructor_type == 0)
6653     ;
6654   else if (TREE_CODE (constructor_type) != RECORD_TYPE
6655            && TREE_CODE (constructor_type) != UNION_TYPE
6656            && TREE_CODE (constructor_type) != ARRAY_TYPE
6657            && TREE_CODE (constructor_type) != VECTOR_TYPE)
6658     {
6659       /* A nonincremental scalar initializer--just return
6660          the element, after verifying there is just one.  */
6661       if (VEC_empty (constructor_elt,constructor_elements))
6662         {
6663           if (!constructor_erroneous)
6664             error_init ("empty scalar initializer");
6665           ret.value = error_mark_node;
6666         }
6667       else if (VEC_length (constructor_elt,constructor_elements) != 1)
6668         {
6669           error_init ("extra elements in scalar initializer");
6670           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6671         }
6672       else
6673         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
6674     }
6675   else
6676     {
6677       if (constructor_erroneous)
6678         ret.value = error_mark_node;
6679       else
6680         {
6681           ret.value = build_constructor (constructor_type,
6682                                          constructor_elements);
6683           if (constructor_constant)
6684             TREE_CONSTANT (ret.value) = 1;
6685           if (constructor_constant && constructor_simple)
6686             TREE_STATIC (ret.value) = 1;
6687           if (constructor_nonconst)
6688             CONSTRUCTOR_NON_CONST (ret.value) = 1;
6689         }
6690     }
6691
6692   if (ret.value && TREE_CODE (ret.value) != CONSTRUCTOR)
6693     {
6694       if (constructor_nonconst)
6695         ret.original_code = C_MAYBE_CONST_EXPR;
6696       else if (ret.original_code == C_MAYBE_CONST_EXPR)
6697         ret.original_code = ERROR_MARK;
6698     }
6699
6700   constructor_type = p->type;
6701   constructor_fields = p->fields;
6702   constructor_index = p->index;
6703   constructor_max_index = p->max_index;
6704   constructor_unfilled_index = p->unfilled_index;
6705   constructor_unfilled_fields = p->unfilled_fields;
6706   constructor_bit_index = p->bit_index;
6707   constructor_elements = p->elements;
6708   constructor_constant = p->constant;
6709   constructor_simple = p->simple;
6710   constructor_nonconst = p->nonconst;
6711   constructor_erroneous = p->erroneous;
6712   constructor_incremental = p->incremental;
6713   constructor_designated = p->designated;
6714   constructor_pending_elts = p->pending_elts;
6715   constructor_depth = p->depth;
6716   if (!p->implicit)
6717     constructor_range_stack = p->range_stack;
6718   RESTORE_SPELLING_DEPTH (constructor_depth);
6719
6720   constructor_stack = p->next;
6721   free (p);
6722
6723   if (ret.value == 0 && constructor_stack == 0)
6724     ret.value = error_mark_node;
6725   return ret;
6726 }
6727
6728 /* Common handling for both array range and field name designators.
6729    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
6730
6731 static int
6732 set_designator (int array)
6733 {
6734   tree subtype;
6735   enum tree_code subcode;
6736
6737   /* Don't die if an entire brace-pair level is superfluous
6738      in the containing level.  */
6739   if (constructor_type == 0)
6740     return 1;
6741
6742   /* If there were errors in this designator list already, bail out
6743      silently.  */
6744   if (designator_erroneous)
6745     return 1;
6746
6747   if (!designator_depth)
6748     {
6749       gcc_assert (!constructor_range_stack);
6750
6751       /* Designator list starts at the level of closest explicit
6752          braces.  */
6753       while (constructor_stack->implicit)
6754         process_init_element (pop_init_level (1), true);
6755       constructor_designated = 1;
6756       return 0;
6757     }
6758
6759   switch (TREE_CODE (constructor_type))
6760     {
6761     case  RECORD_TYPE:
6762     case  UNION_TYPE:
6763       subtype = TREE_TYPE (constructor_fields);
6764       if (subtype != error_mark_node)
6765         subtype = TYPE_MAIN_VARIANT (subtype);
6766       break;
6767     case ARRAY_TYPE:
6768       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6769       break;
6770     default:
6771       gcc_unreachable ();
6772     }
6773
6774   subcode = TREE_CODE (subtype);
6775   if (array && subcode != ARRAY_TYPE)
6776     {
6777       error_init ("array index in non-array initializer");
6778       return 1;
6779     }
6780   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
6781     {
6782       error_init ("field name not in record or union initializer");
6783       return 1;
6784     }
6785
6786   constructor_designated = 1;
6787   push_init_level (2);
6788   return 0;
6789 }
6790
6791 /* If there are range designators in designator list, push a new designator
6792    to constructor_range_stack.  RANGE_END is end of such stack range or
6793    NULL_TREE if there is no range designator at this level.  */
6794
6795 static void
6796 push_range_stack (tree range_end)
6797 {
6798   struct constructor_range_stack *p;
6799
6800   p = GGC_NEW (struct constructor_range_stack);
6801   p->prev = constructor_range_stack;
6802   p->next = 0;
6803   p->fields = constructor_fields;
6804   p->range_start = constructor_index;
6805   p->index = constructor_index;
6806   p->stack = constructor_stack;
6807   p->range_end = range_end;
6808   if (constructor_range_stack)
6809     constructor_range_stack->next = p;
6810   constructor_range_stack = p;
6811 }
6812
6813 /* Within an array initializer, specify the next index to be initialized.
6814    FIRST is that index.  If LAST is nonzero, then initialize a range
6815    of indices, running from FIRST through LAST.  */
6816
6817 void
6818 set_init_index (tree first, tree last)
6819 {
6820   if (set_designator (1))
6821     return;
6822
6823   designator_erroneous = 1;
6824
6825   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
6826       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
6827     {
6828       error_init ("array index in initializer not of integer type");
6829       return;
6830     }
6831
6832   if (TREE_CODE (first) != INTEGER_CST)
6833     {
6834       first = c_fully_fold (first, false, NULL);
6835       if (TREE_CODE (first) == INTEGER_CST)
6836         pedwarn_init (input_location, OPT_pedantic,
6837                       "array index in initializer is not "
6838                       "an integer constant expression");
6839     }
6840
6841   if (last && TREE_CODE (last) != INTEGER_CST)
6842     {
6843       last = c_fully_fold (last, false, NULL);
6844       if (TREE_CODE (last) == INTEGER_CST)
6845         pedwarn_init (input_location, OPT_pedantic,
6846                       "array index in initializer is not "
6847                       "an integer constant expression");
6848     }
6849
6850   if (TREE_CODE (first) != INTEGER_CST)
6851     error_init ("nonconstant array index in initializer");
6852   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
6853     error_init ("nonconstant array index in initializer");
6854   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
6855     error_init ("array index in non-array initializer");
6856   else if (tree_int_cst_sgn (first) == -1)
6857     error_init ("array index in initializer exceeds array bounds");
6858   else if (constructor_max_index
6859            && tree_int_cst_lt (constructor_max_index, first))
6860     error_init ("array index in initializer exceeds array bounds");
6861   else
6862     {
6863       constant_expression_warning (first);
6864       if (last)
6865         constant_expression_warning (last);
6866       constructor_index = convert (bitsizetype, first);
6867
6868       if (last)
6869         {
6870           if (tree_int_cst_equal (first, last))
6871             last = 0;
6872           else if (tree_int_cst_lt (last, first))
6873             {
6874               error_init ("empty index range in initializer");
6875               last = 0;
6876             }
6877           else
6878             {
6879               last = convert (bitsizetype, last);
6880               if (constructor_max_index != 0
6881                   && tree_int_cst_lt (constructor_max_index, last))
6882                 {
6883                   error_init ("array index range in initializer exceeds array bounds");
6884                   last = 0;
6885                 }
6886             }
6887         }
6888
6889       designator_depth++;
6890       designator_erroneous = 0;
6891       if (constructor_range_stack || last)
6892         push_range_stack (last);
6893     }
6894 }
6895
6896 /* Within a struct initializer, specify the next field to be initialized.  */
6897
6898 void
6899 set_init_label (tree fieldname)
6900 {
6901   tree tail;
6902
6903   if (set_designator (0))
6904     return;
6905
6906   designator_erroneous = 1;
6907
6908   if (TREE_CODE (constructor_type) != RECORD_TYPE
6909       && TREE_CODE (constructor_type) != UNION_TYPE)
6910     {
6911       error_init ("field name not in record or union initializer");
6912       return;
6913     }
6914
6915   for (tail = TYPE_FIELDS (constructor_type); tail;
6916        tail = TREE_CHAIN (tail))
6917     {
6918       if (DECL_NAME (tail) == fieldname)
6919         break;
6920     }
6921
6922   if (tail == 0)
6923     error ("unknown field %qE specified in initializer", fieldname);
6924   else
6925     {
6926       constructor_fields = tail;
6927       designator_depth++;
6928       designator_erroneous = 0;
6929       if (constructor_range_stack)
6930         push_range_stack (NULL_TREE);
6931     }
6932 }
6933 \f
6934 /* Add a new initializer to the tree of pending initializers.  PURPOSE
6935    identifies the initializer, either array index or field in a structure.
6936    VALUE is the value of that index or field.  If ORIGTYPE is not
6937    NULL_TREE, it is the original type of VALUE.
6938
6939    IMPLICIT is true if value comes from pop_init_level (1),
6940    the new initializer has been merged with the existing one
6941    and thus no warnings should be emitted about overriding an
6942    existing initializer.  */
6943
6944 static void
6945 add_pending_init (tree purpose, tree value, tree origtype, bool implicit)
6946 {
6947   struct init_node *p, **q, *r;
6948
6949   q = &constructor_pending_elts;
6950   p = 0;
6951
6952   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6953     {
6954       while (*q != 0)
6955         {
6956           p = *q;
6957           if (tree_int_cst_lt (purpose, p->purpose))
6958             q = &p->left;
6959           else if (tree_int_cst_lt (p->purpose, purpose))
6960             q = &p->right;
6961           else
6962             {
6963               if (!implicit)
6964                 {
6965                   if (TREE_SIDE_EFFECTS (p->value))
6966                     warning_init (0, "initialized field with side-effects overwritten");
6967                   else if (warn_override_init)
6968                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6969                 }
6970               p->value = value;
6971               p->origtype = origtype;
6972               return;
6973             }
6974         }
6975     }
6976   else
6977     {
6978       tree bitpos;
6979
6980       bitpos = bit_position (purpose);
6981       while (*q != NULL)
6982         {
6983           p = *q;
6984           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6985             q = &p->left;
6986           else if (p->purpose != purpose)
6987             q = &p->right;
6988           else
6989             {
6990               if (!implicit)
6991                 {
6992                   if (TREE_SIDE_EFFECTS (p->value))
6993                     warning_init (0, "initialized field with side-effects overwritten");
6994                   else if (warn_override_init)
6995                     warning_init (OPT_Woverride_init, "initialized field overwritten");
6996                 }
6997               p->value = value;
6998               p->origtype = origtype;
6999               return;
7000             }
7001         }
7002     }
7003
7004   r = GGC_NEW (struct init_node);
7005   r->purpose = purpose;
7006   r->value = value;
7007   r->origtype = origtype;
7008
7009   *q = r;
7010   r->parent = p;
7011   r->left = 0;
7012   r->right = 0;
7013   r->balance = 0;
7014
7015   while (p)
7016     {
7017       struct init_node *s;
7018
7019       if (r == p->left)
7020         {
7021           if (p->balance == 0)
7022             p->balance = -1;
7023           else if (p->balance < 0)
7024             {
7025               if (r->balance < 0)
7026                 {
7027                   /* L rotation.  */
7028                   p->left = r->right;
7029                   if (p->left)
7030                     p->left->parent = p;
7031                   r->right = p;
7032
7033                   p->balance = 0;
7034                   r->balance = 0;
7035
7036                   s = p->parent;
7037                   p->parent = r;
7038                   r->parent = s;
7039                   if (s)
7040                     {
7041                       if (s->left == p)
7042                         s->left = r;
7043                       else
7044                         s->right = r;
7045                     }
7046                   else
7047                     constructor_pending_elts = r;
7048                 }
7049               else
7050                 {
7051                   /* LR rotation.  */
7052                   struct init_node *t = r->right;
7053
7054                   r->right = t->left;
7055                   if (r->right)
7056                     r->right->parent = r;
7057                   t->left = r;
7058
7059                   p->left = t->right;
7060                   if (p->left)
7061                     p->left->parent = p;
7062                   t->right = p;
7063
7064                   p->balance = t->balance < 0;
7065                   r->balance = -(t->balance > 0);
7066                   t->balance = 0;
7067
7068                   s = p->parent;
7069                   p->parent = t;
7070                   r->parent = t;
7071                   t->parent = s;
7072                   if (s)
7073                     {
7074                       if (s->left == p)
7075                         s->left = t;
7076                       else
7077                         s->right = t;
7078                     }
7079                   else
7080                     constructor_pending_elts = t;
7081                 }
7082               break;
7083             }
7084           else
7085             {
7086               /* p->balance == +1; growth of left side balances the node.  */
7087               p->balance = 0;
7088               break;
7089             }
7090         }
7091       else /* r == p->right */
7092         {
7093           if (p->balance == 0)
7094             /* Growth propagation from right side.  */
7095             p->balance++;
7096           else if (p->balance > 0)
7097             {
7098               if (r->balance > 0)
7099                 {
7100                   /* R rotation.  */
7101                   p->right = r->left;
7102                   if (p->right)
7103                     p->right->parent = p;
7104                   r->left = p;
7105
7106                   p->balance = 0;
7107                   r->balance = 0;
7108
7109                   s = p->parent;
7110                   p->parent = r;
7111                   r->parent = s;
7112                   if (s)
7113                     {
7114                       if (s->left == p)
7115                         s->left = r;
7116                       else
7117                         s->right = r;
7118                     }
7119                   else
7120                     constructor_pending_elts = r;
7121                 }
7122               else /* r->balance == -1 */
7123                 {
7124                   /* RL rotation */
7125                   struct init_node *t = r->left;
7126
7127                   r->left = t->right;
7128                   if (r->left)
7129                     r->left->parent = r;
7130                   t->right = r;
7131
7132                   p->right = t->left;
7133                   if (p->right)
7134                     p->right->parent = p;
7135                   t->left = p;
7136
7137                   r->balance = (t->balance < 0);
7138                   p->balance = -(t->balance > 0);
7139                   t->balance = 0;
7140
7141                   s = p->parent;
7142                   p->parent = t;
7143                   r->parent = t;
7144                   t->parent = s;
7145                   if (s)
7146                     {
7147                       if (s->left == p)
7148                         s->left = t;
7149                       else
7150                         s->right = t;
7151                     }
7152                   else
7153                     constructor_pending_elts = t;
7154                 }
7155               break;
7156             }
7157           else
7158             {
7159               /* p->balance == -1; growth of right side balances the node.  */
7160               p->balance = 0;
7161               break;
7162             }
7163         }
7164
7165       r = p;
7166       p = p->parent;
7167     }
7168 }
7169
7170 /* Build AVL tree from a sorted chain.  */
7171
7172 static void
7173 set_nonincremental_init (void)
7174 {
7175   unsigned HOST_WIDE_INT ix;
7176   tree index, value;
7177
7178   if (TREE_CODE (constructor_type) != RECORD_TYPE
7179       && TREE_CODE (constructor_type) != ARRAY_TYPE)
7180     return;
7181
7182   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
7183     add_pending_init (index, value, NULL_TREE, false);
7184   constructor_elements = 0;
7185   if (TREE_CODE (constructor_type) == RECORD_TYPE)
7186     {
7187       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
7188       /* Skip any nameless bit fields at the beginning.  */
7189       while (constructor_unfilled_fields != 0
7190              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7191              && DECL_NAME (constructor_unfilled_fields) == 0)
7192         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
7193
7194     }
7195   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7196     {
7197       if (TYPE_DOMAIN (constructor_type))
7198         constructor_unfilled_index
7199             = convert (bitsizetype,
7200                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
7201       else
7202         constructor_unfilled_index = bitsize_zero_node;
7203     }
7204   constructor_incremental = 0;
7205 }
7206
7207 /* Build AVL tree from a string constant.  */
7208
7209 static void
7210 set_nonincremental_init_from_string (tree str)
7211 {
7212   tree value, purpose, type;
7213   HOST_WIDE_INT val[2];
7214   const char *p, *end;
7215   int byte, wchar_bytes, charwidth, bitpos;
7216
7217   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
7218
7219   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
7220   charwidth = TYPE_PRECISION (char_type_node);
7221   type = TREE_TYPE (constructor_type);
7222   p = TREE_STRING_POINTER (str);
7223   end = p + TREE_STRING_LENGTH (str);
7224
7225   for (purpose = bitsize_zero_node;
7226        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
7227        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
7228     {
7229       if (wchar_bytes == 1)
7230         {
7231           val[1] = (unsigned char) *p++;
7232           val[0] = 0;
7233         }
7234       else
7235         {
7236           val[0] = 0;
7237           val[1] = 0;
7238           for (byte = 0; byte < wchar_bytes; byte++)
7239             {
7240               if (BYTES_BIG_ENDIAN)
7241                 bitpos = (wchar_bytes - byte - 1) * charwidth;
7242               else
7243                 bitpos = byte * charwidth;
7244               val[bitpos < HOST_BITS_PER_WIDE_INT]
7245                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
7246                    << (bitpos % HOST_BITS_PER_WIDE_INT);
7247             }
7248         }
7249
7250       if (!TYPE_UNSIGNED (type))
7251         {
7252           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
7253           if (bitpos < HOST_BITS_PER_WIDE_INT)
7254             {
7255               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
7256                 {
7257                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
7258                   val[0] = -1;
7259                 }
7260             }
7261           else if (bitpos == HOST_BITS_PER_WIDE_INT)
7262             {
7263               if (val[1] < 0)
7264                 val[0] = -1;
7265             }
7266           else if (val[0] & (((HOST_WIDE_INT) 1)
7267                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
7268             val[0] |= ((HOST_WIDE_INT) -1)
7269                       << (bitpos - HOST_BITS_PER_WIDE_INT);
7270         }
7271
7272       value = build_int_cst_wide (type, val[1], val[0]);
7273       add_pending_init (purpose, value, NULL_TREE, false);
7274     }
7275
7276   constructor_incremental = 0;
7277 }
7278
7279 /* Return value of FIELD in pending initializer or zero if the field was
7280    not initialized yet.  */
7281
7282 static tree
7283 find_init_member (tree field)
7284 {
7285   struct init_node *p;
7286
7287   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7288     {
7289       if (constructor_incremental
7290           && tree_int_cst_lt (field, constructor_unfilled_index))
7291         set_nonincremental_init ();
7292
7293       p = constructor_pending_elts;
7294       while (p)
7295         {
7296           if (tree_int_cst_lt (field, p->purpose))
7297             p = p->left;
7298           else if (tree_int_cst_lt (p->purpose, field))
7299             p = p->right;
7300           else
7301             return p->value;
7302         }
7303     }
7304   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7305     {
7306       tree bitpos = bit_position (field);
7307
7308       if (constructor_incremental
7309           && (!constructor_unfilled_fields
7310               || tree_int_cst_lt (bitpos,
7311                                   bit_position (constructor_unfilled_fields))))
7312         set_nonincremental_init ();
7313
7314       p = constructor_pending_elts;
7315       while (p)
7316         {
7317           if (field == p->purpose)
7318             return p->value;
7319           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
7320             p = p->left;
7321           else
7322             p = p->right;
7323         }
7324     }
7325   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7326     {
7327       if (!VEC_empty (constructor_elt, constructor_elements)
7328           && (VEC_last (constructor_elt, constructor_elements)->index
7329               == field))
7330         return VEC_last (constructor_elt, constructor_elements)->value;
7331     }
7332   return 0;
7333 }
7334
7335 /* "Output" the next constructor element.
7336    At top level, really output it to assembler code now.
7337    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
7338    If ORIGTYPE is not NULL_TREE, it is the original type of VALUE.
7339    TYPE is the data type that the containing data type wants here.
7340    FIELD is the field (a FIELD_DECL) or the index that this element fills.
7341    If VALUE is a string constant, STRICT_STRING is true if it is
7342    unparenthesized or we should not warn here for it being parenthesized.
7343    For other types of VALUE, STRICT_STRING is not used.
7344
7345    PENDING if non-nil means output pending elements that belong
7346    right after this element.  (PENDING is normally 1;
7347    it is 0 while outputting pending elements, to avoid recursion.)
7348
7349    IMPLICIT is true if value comes from pop_init_level (1),
7350    the new initializer has been merged with the existing one
7351    and thus no warnings should be emitted about overriding an
7352    existing initializer.  */
7353
7354 static void
7355 output_init_element (tree value, tree origtype, bool strict_string, tree type,
7356                      tree field, int pending, bool implicit)
7357 {
7358   tree semantic_type = NULL_TREE;
7359   constructor_elt *celt;
7360   bool maybe_const = true;
7361   bool npc;
7362
7363   if (type == error_mark_node || value == error_mark_node)
7364     {
7365       constructor_erroneous = 1;
7366       return;
7367     }
7368   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
7369       && (TREE_CODE (value) == STRING_CST
7370           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
7371       && !(TREE_CODE (value) == STRING_CST
7372            && TREE_CODE (type) == ARRAY_TYPE
7373            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
7374       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
7375                      TYPE_MAIN_VARIANT (type)))
7376     value = array_to_pointer_conversion (input_location, value);
7377
7378   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
7379       && require_constant_value && !flag_isoc99 && pending)
7380     {
7381       /* As an extension, allow initializing objects with static storage
7382          duration with compound literals (which are then treated just as
7383          the brace enclosed list they contain).  */
7384       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
7385       value = DECL_INITIAL (decl);
7386     }
7387
7388   npc = null_pointer_constant_p (value);
7389   if (TREE_CODE (value) == EXCESS_PRECISION_EXPR)
7390     {
7391       semantic_type = TREE_TYPE (value);
7392       value = TREE_OPERAND (value, 0);
7393     }
7394   value = c_fully_fold (value, require_constant_value, &maybe_const);
7395
7396   if (value == error_mark_node)
7397     constructor_erroneous = 1;
7398   else if (!TREE_CONSTANT (value))
7399     constructor_constant = 0;
7400   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
7401            || ((TREE_CODE (constructor_type) == RECORD_TYPE
7402                 || TREE_CODE (constructor_type) == UNION_TYPE)
7403                && DECL_C_BIT_FIELD (field)
7404                && TREE_CODE (value) != INTEGER_CST))
7405     constructor_simple = 0;
7406   if (!maybe_const)
7407     constructor_nonconst = 1;
7408
7409   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
7410     {
7411       if (require_constant_value)
7412         {
7413           error_init ("initializer element is not constant");
7414           value = error_mark_node;
7415         }
7416       else if (require_constant_elements)
7417         pedwarn (input_location, 0,
7418                  "initializer element is not computable at load time");
7419     }
7420   else if (!maybe_const
7421            && (require_constant_value || require_constant_elements))
7422     pedwarn_init (input_location, 0,
7423                   "initializer element is not a constant expression");
7424
7425   /* Issue -Wc++-compat warnings about initializing a bitfield with
7426      enum type.  */
7427   if (warn_cxx_compat
7428       && field != NULL_TREE
7429       && TREE_CODE (field) == FIELD_DECL
7430       && DECL_BIT_FIELD_TYPE (field) != NULL_TREE
7431       && (TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))
7432           != TYPE_MAIN_VARIANT (type))
7433       && TREE_CODE (DECL_BIT_FIELD_TYPE (field)) == ENUMERAL_TYPE)
7434     {
7435       tree checktype = origtype != NULL_TREE ? origtype : TREE_TYPE (value);
7436       if (checktype != error_mark_node
7437           && (TYPE_MAIN_VARIANT (checktype)
7438               != TYPE_MAIN_VARIANT (DECL_BIT_FIELD_TYPE (field))))
7439         warning_init (OPT_Wc___compat,
7440                       "enum conversion in initialization is invalid in C++");
7441     }
7442
7443   /* If this field is empty (and not at the end of structure),
7444      don't do anything other than checking the initializer.  */
7445   if (field
7446       && (TREE_TYPE (field) == error_mark_node
7447           || (COMPLETE_TYPE_P (TREE_TYPE (field))
7448               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
7449               && (TREE_CODE (constructor_type) == ARRAY_TYPE
7450                   || TREE_CHAIN (field)))))
7451     return;
7452
7453   if (semantic_type)
7454     value = build1 (EXCESS_PRECISION_EXPR, semantic_type, value);
7455   value = digest_init (input_location, type, value, origtype, npc,
7456                        strict_string, require_constant_value);
7457   if (value == error_mark_node)
7458     {
7459       constructor_erroneous = 1;
7460       return;
7461     }
7462   if (require_constant_value || require_constant_elements)
7463     constant_expression_warning (value);
7464
7465   /* If this element doesn't come next in sequence,
7466      put it on constructor_pending_elts.  */
7467   if (TREE_CODE (constructor_type) == ARRAY_TYPE
7468       && (!constructor_incremental
7469           || !tree_int_cst_equal (field, constructor_unfilled_index)))
7470     {
7471       if (constructor_incremental
7472           && tree_int_cst_lt (field, constructor_unfilled_index))
7473         set_nonincremental_init ();
7474
7475       add_pending_init (field, value, origtype, implicit);
7476       return;
7477     }
7478   else if (TREE_CODE (constructor_type) == RECORD_TYPE
7479            && (!constructor_incremental
7480                || field != constructor_unfilled_fields))
7481     {
7482       /* We do this for records but not for unions.  In a union,
7483          no matter which field is specified, it can be initialized
7484          right away since it starts at the beginning of the union.  */
7485       if (constructor_incremental)
7486         {
7487           if (!constructor_unfilled_fields)
7488             set_nonincremental_init ();
7489           else
7490             {
7491               tree bitpos, unfillpos;
7492
7493               bitpos = bit_position (field);
7494               unfillpos = bit_position (constructor_unfilled_fields);
7495
7496               if (tree_int_cst_lt (bitpos, unfillpos))
7497                 set_nonincremental_init ();
7498             }
7499         }
7500
7501       add_pending_init (field, value, origtype, implicit);
7502       return;
7503     }
7504   else if (TREE_CODE (constructor_type) == UNION_TYPE
7505            && !VEC_empty (constructor_elt, constructor_elements))
7506     {
7507       if (!implicit)
7508         {
7509           if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
7510                                            constructor_elements)->value))
7511             warning_init (0,
7512                           "initialized field with side-effects overwritten");
7513           else if (warn_override_init)
7514             warning_init (OPT_Woverride_init, "initialized field overwritten");
7515         }
7516
7517       /* We can have just one union field set.  */
7518       constructor_elements = 0;
7519     }
7520
7521   /* Otherwise, output this element either to
7522      constructor_elements or to the assembler file.  */
7523
7524   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
7525   celt->index = field;
7526   celt->value = value;
7527
7528   /* Advance the variable that indicates sequential elements output.  */
7529   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7530     constructor_unfilled_index
7531       = size_binop_loc (input_location, PLUS_EXPR, constructor_unfilled_index,
7532                         bitsize_one_node);
7533   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
7534     {
7535       constructor_unfilled_fields
7536         = TREE_CHAIN (constructor_unfilled_fields);
7537
7538       /* Skip any nameless bit fields.  */
7539       while (constructor_unfilled_fields != 0
7540              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7541              && DECL_NAME (constructor_unfilled_fields) == 0)
7542         constructor_unfilled_fields =
7543           TREE_CHAIN (constructor_unfilled_fields);
7544     }
7545   else if (TREE_CODE (constructor_type) == UNION_TYPE)
7546     constructor_unfilled_fields = 0;
7547
7548   /* Now output any pending elements which have become next.  */
7549   if (pending)
7550     output_pending_init_elements (0);
7551 }
7552
7553 /* Output any pending elements which have become next.
7554    As we output elements, constructor_unfilled_{fields,index}
7555    advances, which may cause other elements to become next;
7556    if so, they too are output.
7557
7558    If ALL is 0, we return when there are
7559    no more pending elements to output now.
7560
7561    If ALL is 1, we output space as necessary so that
7562    we can output all the pending elements.  */
7563
7564 static void
7565 output_pending_init_elements (int all)
7566 {
7567   struct init_node *elt = constructor_pending_elts;
7568   tree next;
7569
7570  retry:
7571
7572   /* Look through the whole pending tree.
7573      If we find an element that should be output now,
7574      output it.  Otherwise, set NEXT to the element
7575      that comes first among those still pending.  */
7576
7577   next = 0;
7578   while (elt)
7579     {
7580       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7581         {
7582           if (tree_int_cst_equal (elt->purpose,
7583                                   constructor_unfilled_index))
7584             output_init_element (elt->value, elt->origtype, true,
7585                                  TREE_TYPE (constructor_type),
7586                                  constructor_unfilled_index, 0, false);
7587           else if (tree_int_cst_lt (constructor_unfilled_index,
7588                                     elt->purpose))
7589             {
7590               /* Advance to the next smaller node.  */
7591               if (elt->left)
7592                 elt = elt->left;
7593               else
7594                 {
7595                   /* We have reached the smallest node bigger than the
7596                      current unfilled index.  Fill the space first.  */
7597                   next = elt->purpose;
7598                   break;
7599                 }
7600             }
7601           else
7602             {
7603               /* Advance to the next bigger node.  */
7604               if (elt->right)
7605                 elt = elt->right;
7606               else
7607                 {
7608                   /* We have reached the biggest node in a subtree.  Find
7609                      the parent of it, which is the next bigger node.  */
7610                   while (elt->parent && elt->parent->right == elt)
7611                     elt = elt->parent;
7612                   elt = elt->parent;
7613                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
7614                                               elt->purpose))
7615                     {
7616                       next = elt->purpose;
7617                       break;
7618                     }
7619                 }
7620             }
7621         }
7622       else if (TREE_CODE (constructor_type) == RECORD_TYPE
7623                || TREE_CODE (constructor_type) == UNION_TYPE)
7624         {
7625           tree ctor_unfilled_bitpos, elt_bitpos;
7626
7627           /* If the current record is complete we are done.  */
7628           if (constructor_unfilled_fields == 0)
7629             break;
7630
7631           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
7632           elt_bitpos = bit_position (elt->purpose);
7633           /* We can't compare fields here because there might be empty
7634              fields in between.  */
7635           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
7636             {
7637               constructor_unfilled_fields = elt->purpose;
7638               output_init_element (elt->value, elt->origtype, true,
7639                                    TREE_TYPE (elt->purpose),
7640                                    elt->purpose, 0, false);
7641             }
7642           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
7643             {
7644               /* Advance to the next smaller node.  */
7645               if (elt->left)
7646                 elt = elt->left;
7647               else
7648                 {
7649                   /* We have reached the smallest node bigger than the
7650                      current unfilled field.  Fill the space first.  */
7651                   next = elt->purpose;
7652                   break;
7653                 }
7654             }
7655           else
7656             {
7657               /* Advance to the next bigger node.  */
7658               if (elt->right)
7659                 elt = elt->right;
7660               else
7661                 {
7662                   /* We have reached the biggest node in a subtree.  Find
7663                      the parent of it, which is the next bigger node.  */
7664                   while (elt->parent && elt->parent->right == elt)
7665                     elt = elt->parent;
7666                   elt = elt->parent;
7667                   if (elt
7668                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
7669                                            bit_position (elt->purpose))))
7670                     {
7671                       next = elt->purpose;
7672                       break;
7673                     }
7674                 }
7675             }
7676         }
7677     }
7678
7679   /* Ordinarily return, but not if we want to output all
7680      and there are elements left.  */
7681   if (!(all && next != 0))
7682     return;
7683
7684   /* If it's not incremental, just skip over the gap, so that after
7685      jumping to retry we will output the next successive element.  */
7686   if (TREE_CODE (constructor_type) == RECORD_TYPE
7687       || TREE_CODE (constructor_type) == UNION_TYPE)
7688     constructor_unfilled_fields = next;
7689   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7690     constructor_unfilled_index = next;
7691
7692   /* ELT now points to the node in the pending tree with the next
7693      initializer to output.  */
7694   goto retry;
7695 }
7696 \f
7697 /* Add one non-braced element to the current constructor level.
7698    This adjusts the current position within the constructor's type.
7699    This may also start or terminate implicit levels
7700    to handle a partly-braced initializer.
7701
7702    Once this has found the correct level for the new element,
7703    it calls output_init_element.
7704
7705    IMPLICIT is true if value comes from pop_init_level (1),
7706    the new initializer has been merged with the existing one
7707    and thus no warnings should be emitted about overriding an
7708    existing initializer.  */
7709
7710 void
7711 process_init_element (struct c_expr value, bool implicit)
7712 {
7713   tree orig_value = value.value;
7714   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
7715   bool strict_string = value.original_code == STRING_CST;
7716
7717   designator_depth = 0;
7718   designator_erroneous = 0;
7719
7720   /* Handle superfluous braces around string cst as in
7721      char x[] = {"foo"}; */
7722   if (string_flag
7723       && constructor_type
7724       && TREE_CODE (constructor_type) == ARRAY_TYPE
7725       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
7726       && integer_zerop (constructor_unfilled_index))
7727     {
7728       if (constructor_stack->replacement_value.value)
7729         error_init ("excess elements in char array initializer");
7730       constructor_stack->replacement_value = value;
7731       return;
7732     }
7733
7734   if (constructor_stack->replacement_value.value != 0)
7735     {
7736       error_init ("excess elements in struct initializer");
7737       return;
7738     }
7739
7740   /* Ignore elements of a brace group if it is entirely superfluous
7741      and has already been diagnosed.  */
7742   if (constructor_type == 0)
7743     return;
7744
7745   /* If we've exhausted any levels that didn't have braces,
7746      pop them now.  */
7747   while (constructor_stack->implicit)
7748     {
7749       if ((TREE_CODE (constructor_type) == RECORD_TYPE
7750            || TREE_CODE (constructor_type) == UNION_TYPE)
7751           && constructor_fields == 0)
7752         process_init_element (pop_init_level (1), true);
7753       else if ((TREE_CODE (constructor_type) == ARRAY_TYPE
7754                 || TREE_CODE (constructor_type) == VECTOR_TYPE)
7755                && (constructor_max_index == 0
7756                    || tree_int_cst_lt (constructor_max_index,
7757                                        constructor_index)))
7758         process_init_element (pop_init_level (1), true);
7759       else
7760         break;
7761     }
7762
7763   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
7764   if (constructor_range_stack)
7765     {
7766       /* If value is a compound literal and we'll be just using its
7767          content, don't put it into a SAVE_EXPR.  */
7768       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
7769           || !require_constant_value
7770           || flag_isoc99)
7771         {
7772           tree semantic_type = NULL_TREE;
7773           if (TREE_CODE (value.value) == EXCESS_PRECISION_EXPR)
7774             {
7775               semantic_type = TREE_TYPE (value.value);
7776               value.value = TREE_OPERAND (value.value, 0);
7777             }
7778           value.value = c_save_expr (value.value);
7779           if (semantic_type)
7780             value.value = build1 (EXCESS_PRECISION_EXPR, semantic_type,
7781                                   value.value);
7782         }
7783     }
7784
7785   while (1)
7786     {
7787       if (TREE_CODE (constructor_type) == RECORD_TYPE)
7788         {
7789           tree fieldtype;
7790           enum tree_code fieldcode;
7791
7792           if (constructor_fields == 0)
7793             {
7794               pedwarn_init (input_location, 0,
7795                             "excess elements in struct initializer");
7796               break;
7797             }
7798
7799           fieldtype = TREE_TYPE (constructor_fields);
7800           if (fieldtype != error_mark_node)
7801             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7802           fieldcode = TREE_CODE (fieldtype);
7803
7804           /* Error for non-static initialization of a flexible array member.  */
7805           if (fieldcode == ARRAY_TYPE
7806               && !require_constant_value
7807               && TYPE_SIZE (fieldtype) == NULL_TREE
7808               && TREE_CHAIN (constructor_fields) == NULL_TREE)
7809             {
7810               error_init ("non-static initialization of a flexible array member");
7811               break;
7812             }
7813
7814           /* Accept a string constant to initialize a subarray.  */
7815           if (value.value != 0
7816               && fieldcode == ARRAY_TYPE
7817               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7818               && string_flag)
7819             value.value = orig_value;
7820           /* Otherwise, if we have come to a subaggregate,
7821              and we don't have an element of its type, push into it.  */
7822           else if (value.value != 0
7823                    && value.value != error_mark_node
7824                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7825                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7826                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7827             {
7828               push_init_level (1);
7829               continue;
7830             }
7831
7832           if (value.value)
7833             {
7834               push_member_name (constructor_fields);
7835               output_init_element (value.value, value.original_type,
7836                                    strict_string, fieldtype,
7837                                    constructor_fields, 1, implicit);
7838               RESTORE_SPELLING_DEPTH (constructor_depth);
7839             }
7840           else
7841             /* Do the bookkeeping for an element that was
7842                directly output as a constructor.  */
7843             {
7844               /* For a record, keep track of end position of last field.  */
7845               if (DECL_SIZE (constructor_fields))
7846                 constructor_bit_index
7847                   = size_binop_loc (input_location, PLUS_EXPR,
7848                                     bit_position (constructor_fields),
7849                                     DECL_SIZE (constructor_fields));
7850
7851               /* If the current field was the first one not yet written out,
7852                  it isn't now, so update.  */
7853               if (constructor_unfilled_fields == constructor_fields)
7854                 {
7855                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7856                   /* Skip any nameless bit fields.  */
7857                   while (constructor_unfilled_fields != 0
7858                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
7859                          && DECL_NAME (constructor_unfilled_fields) == 0)
7860                     constructor_unfilled_fields =
7861                       TREE_CHAIN (constructor_unfilled_fields);
7862                 }
7863             }
7864
7865           constructor_fields = TREE_CHAIN (constructor_fields);
7866           /* Skip any nameless bit fields at the beginning.  */
7867           while (constructor_fields != 0
7868                  && DECL_C_BIT_FIELD (constructor_fields)
7869                  && DECL_NAME (constructor_fields) == 0)
7870             constructor_fields = TREE_CHAIN (constructor_fields);
7871         }
7872       else if (TREE_CODE (constructor_type) == UNION_TYPE)
7873         {
7874           tree fieldtype;
7875           enum tree_code fieldcode;
7876
7877           if (constructor_fields == 0)
7878             {
7879               pedwarn_init (input_location, 0,
7880                             "excess elements in union initializer");
7881               break;
7882             }
7883
7884           fieldtype = TREE_TYPE (constructor_fields);
7885           if (fieldtype != error_mark_node)
7886             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
7887           fieldcode = TREE_CODE (fieldtype);
7888
7889           /* Warn that traditional C rejects initialization of unions.
7890              We skip the warning if the value is zero.  This is done
7891              under the assumption that the zero initializer in user
7892              code appears conditioned on e.g. __STDC__ to avoid
7893              "missing initializer" warnings and relies on default
7894              initialization to zero in the traditional C case.
7895              We also skip the warning if the initializer is designated,
7896              again on the assumption that this must be conditional on
7897              __STDC__ anyway (and we've already complained about the
7898              member-designator already).  */
7899           if (!in_system_header && !constructor_designated
7900               && !(value.value && (integer_zerop (value.value)
7901                                    || real_zerop (value.value))))
7902             warning (OPT_Wtraditional, "traditional C rejects initialization "
7903                      "of unions");
7904
7905           /* Accept a string constant to initialize a subarray.  */
7906           if (value.value != 0
7907               && fieldcode == ARRAY_TYPE
7908               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
7909               && string_flag)
7910             value.value = orig_value;
7911           /* Otherwise, if we have come to a subaggregate,
7912              and we don't have an element of its type, push into it.  */
7913           else if (value.value != 0
7914                    && value.value != error_mark_node
7915                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
7916                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
7917                        || fieldcode == UNION_TYPE || fieldcode == VECTOR_TYPE))
7918             {
7919               push_init_level (1);
7920               continue;
7921             }
7922
7923           if (value.value)
7924             {
7925               push_member_name (constructor_fields);
7926               output_init_element (value.value, value.original_type,
7927                                    strict_string, fieldtype,
7928                                    constructor_fields, 1, implicit);
7929               RESTORE_SPELLING_DEPTH (constructor_depth);
7930             }
7931           else
7932             /* Do the bookkeeping for an element that was
7933                directly output as a constructor.  */
7934             {
7935               constructor_bit_index = DECL_SIZE (constructor_fields);
7936               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
7937             }
7938
7939           constructor_fields = 0;
7940         }
7941       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
7942         {
7943           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7944           enum tree_code eltcode = TREE_CODE (elttype);
7945
7946           /* Accept a string constant to initialize a subarray.  */
7947           if (value.value != 0
7948               && eltcode == ARRAY_TYPE
7949               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
7950               && string_flag)
7951             value.value = orig_value;
7952           /* Otherwise, if we have come to a subaggregate,
7953              and we don't have an element of its type, push into it.  */
7954           else if (value.value != 0
7955                    && value.value != error_mark_node
7956                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
7957                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
7958                        || eltcode == UNION_TYPE || eltcode == VECTOR_TYPE))
7959             {
7960               push_init_level (1);
7961               continue;
7962             }
7963
7964           if (constructor_max_index != 0
7965               && (tree_int_cst_lt (constructor_max_index, constructor_index)
7966                   || integer_all_onesp (constructor_max_index)))
7967             {
7968               pedwarn_init (input_location, 0,
7969                             "excess elements in array initializer");
7970               break;
7971             }
7972
7973           /* Now output the actual element.  */
7974           if (value.value)
7975             {
7976               push_array_bounds (tree_low_cst (constructor_index, 1));
7977               output_init_element (value.value, value.original_type,
7978                                    strict_string, elttype,
7979                                    constructor_index, 1, implicit);
7980               RESTORE_SPELLING_DEPTH (constructor_depth);
7981             }
7982
7983           constructor_index
7984             = size_binop_loc (input_location, PLUS_EXPR,
7985                               constructor_index, bitsize_one_node);
7986
7987           if (!value.value)
7988             /* If we are doing the bookkeeping for an element that was
7989                directly output as a constructor, we must update
7990                constructor_unfilled_index.  */
7991             constructor_unfilled_index = constructor_index;
7992         }
7993       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
7994         {
7995           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
7996
7997          /* Do a basic check of initializer size.  Note that vectors
7998             always have a fixed size derived from their type.  */
7999           if (tree_int_cst_lt (constructor_max_index, constructor_index))
8000             {
8001               pedwarn_init (input_location, 0,
8002                             "excess elements in vector initializer");
8003               break;
8004             }
8005
8006           /* Now output the actual element.  */
8007           if (value.value)
8008             {
8009               if (TREE_CODE (value.value) == VECTOR_CST)
8010                 elttype = TYPE_MAIN_VARIANT (constructor_type);
8011               output_init_element (value.value, value.original_type,
8012                                    strict_string, elttype,
8013                                    constructor_index, 1, implicit);
8014             }
8015
8016           constructor_index
8017             = size_binop_loc (input_location,
8018                               PLUS_EXPR, constructor_index, bitsize_one_node);
8019
8020           if (!value.value)
8021             /* If we are doing the bookkeeping for an element that was
8022                directly output as a constructor, we must update
8023                constructor_unfilled_index.  */
8024             constructor_unfilled_index = constructor_index;
8025         }
8026
8027       /* Handle the sole element allowed in a braced initializer
8028          for a scalar variable.  */
8029       else if (constructor_type != error_mark_node
8030                && constructor_fields == 0)
8031         {
8032           pedwarn_init (input_location, 0,
8033                         "excess elements in scalar initializer");
8034           break;
8035         }
8036       else
8037         {
8038           if (value.value)
8039             output_init_element (value.value, value.original_type,
8040                                  strict_string, constructor_type,
8041                                  NULL_TREE, 1, implicit);
8042           constructor_fields = 0;
8043         }
8044
8045       /* Handle range initializers either at this level or anywhere higher
8046          in the designator stack.  */
8047       if (constructor_range_stack)
8048         {
8049           struct constructor_range_stack *p, *range_stack;
8050           int finish = 0;
8051
8052           range_stack = constructor_range_stack;
8053           constructor_range_stack = 0;
8054           while (constructor_stack != range_stack->stack)
8055             {
8056               gcc_assert (constructor_stack->implicit);
8057               process_init_element (pop_init_level (1), true);
8058             }
8059           for (p = range_stack;
8060                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
8061                p = p->prev)
8062             {
8063               gcc_assert (constructor_stack->implicit);
8064               process_init_element (pop_init_level (1), true);
8065             }
8066
8067           p->index = size_binop_loc (input_location,
8068                                      PLUS_EXPR, p->index, bitsize_one_node);
8069           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
8070             finish = 1;
8071
8072           while (1)
8073             {
8074               constructor_index = p->index;
8075               constructor_fields = p->fields;
8076               if (finish && p->range_end && p->index == p->range_start)
8077                 {
8078                   finish = 0;
8079                   p->prev = 0;
8080                 }
8081               p = p->next;
8082               if (!p)
8083                 break;
8084               push_init_level (2);
8085               p->stack = constructor_stack;
8086               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
8087                 p->index = p->range_start;
8088             }
8089
8090           if (!finish)
8091             constructor_range_stack = range_stack;
8092           continue;
8093         }
8094
8095       break;
8096     }
8097
8098   constructor_range_stack = 0;
8099 }
8100 \f
8101 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
8102    (guaranteed to be 'volatile' or null) and ARGS (represented using
8103    an ASM_EXPR node).  */
8104 tree
8105 build_asm_stmt (tree cv_qualifier, tree args)
8106 {
8107   if (!ASM_VOLATILE_P (args) && cv_qualifier)
8108     ASM_VOLATILE_P (args) = 1;
8109   return add_stmt (args);
8110 }
8111
8112 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
8113    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
8114    SIMPLE indicates whether there was anything at all after the
8115    string in the asm expression -- asm("blah") and asm("blah" : )
8116    are subtly different.  We use a ASM_EXPR node to represent this.  */
8117 tree
8118 build_asm_expr (location_t loc, tree string, tree outputs, tree inputs,
8119                 tree clobbers, tree labels, bool simple)
8120 {
8121   tree tail;
8122   tree args;
8123   int i;
8124   const char *constraint;
8125   const char **oconstraints;
8126   bool allows_mem, allows_reg, is_inout;
8127   int ninputs, noutputs;
8128
8129   ninputs = list_length (inputs);
8130   noutputs = list_length (outputs);
8131   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
8132
8133   string = resolve_asm_operand_names (string, outputs, inputs, labels);
8134
8135   /* Remove output conversions that change the type but not the mode.  */
8136   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
8137     {
8138       tree output = TREE_VALUE (tail);
8139
8140       /* ??? Really, this should not be here.  Users should be using a
8141          proper lvalue, dammit.  But there's a long history of using casts
8142          in the output operands.  In cases like longlong.h, this becomes a
8143          primitive form of typechecking -- if the cast can be removed, then
8144          the output operand had a type of the proper width; otherwise we'll
8145          get an error.  Gross, but ...  */
8146       STRIP_NOPS (output);
8147
8148       if (!lvalue_or_else (output, lv_asm))
8149         output = error_mark_node;
8150
8151       if (output != error_mark_node
8152           && (TREE_READONLY (output)
8153               || TYPE_READONLY (TREE_TYPE (output))
8154               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
8155                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
8156                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
8157         readonly_error (output, lv_asm);
8158
8159       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8160       oconstraints[i] = constraint;
8161
8162       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
8163                                    &allows_mem, &allows_reg, &is_inout))
8164         {
8165           /* If the operand is going to end up in memory,
8166              mark it addressable.  */
8167           if (!allows_reg && !c_mark_addressable (output))
8168             output = error_mark_node;
8169         }
8170       else
8171         output = error_mark_node;
8172
8173       TREE_VALUE (tail) = output;
8174     }
8175
8176   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
8177     {
8178       tree input;
8179
8180       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
8181       input = TREE_VALUE (tail);
8182
8183       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
8184                                   oconstraints, &allows_mem, &allows_reg))
8185         {
8186           /* If the operand is going to end up in memory,
8187              mark it addressable.  */
8188           if (!allows_reg && allows_mem)
8189             {
8190               /* Strip the nops as we allow this case.  FIXME, this really
8191                  should be rejected or made deprecated.  */
8192               STRIP_NOPS (input);
8193               if (!c_mark_addressable (input))
8194                 input = error_mark_node;
8195           }
8196         }
8197       else
8198         input = error_mark_node;
8199
8200       TREE_VALUE (tail) = input;
8201     }
8202
8203   /* ASMs with labels cannot have outputs.  This should have been
8204      enforced by the parser.  */
8205   gcc_assert (outputs == NULL || labels == NULL);
8206
8207   args = build_stmt (loc, ASM_EXPR, string, outputs, inputs, clobbers, labels);
8208
8209   /* asm statements without outputs, including simple ones, are treated
8210      as volatile.  */
8211   ASM_INPUT_P (args) = simple;
8212   ASM_VOLATILE_P (args) = (noutputs == 0);
8213
8214   return args;
8215 }
8216 \f
8217 /* Generate a goto statement to LABEL.  LOC is the location of the
8218    GOTO.  */
8219
8220 tree
8221 c_finish_goto_label (location_t loc, tree label)
8222 {
8223   tree decl = lookup_label_for_goto (loc, label);
8224   if (!decl)
8225     return NULL_TREE;
8226   TREE_USED (decl) = 1;
8227   {
8228     tree t = build1 (GOTO_EXPR, void_type_node, decl);
8229     SET_EXPR_LOCATION (t, loc);
8230     return add_stmt (t);
8231   }
8232 }
8233
8234 /* Generate a computed goto statement to EXPR.  LOC is the location of
8235    the GOTO.  */
8236
8237 tree
8238 c_finish_goto_ptr (location_t loc, tree expr)
8239 {
8240   tree t;
8241   pedwarn (loc, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
8242   expr = c_fully_fold (expr, false, NULL);
8243   expr = convert (ptr_type_node, expr);
8244   t = build1 (GOTO_EXPR, void_type_node, expr);
8245   SET_EXPR_LOCATION (t, loc);
8246   return add_stmt (t);
8247 }
8248
8249 /* Generate a C `return' statement.  RETVAL is the expression for what
8250    to return, or a null pointer for `return;' with no value.  LOC is
8251    the location of the return statement.  If ORIGTYPE is not NULL_TREE, it
8252    is the original type of RETVAL.  */
8253
8254 tree
8255 c_finish_return (location_t loc, tree retval, tree origtype)
8256 {
8257   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
8258   bool no_warning = false;
8259   bool npc = false;
8260
8261   if (TREE_THIS_VOLATILE (current_function_decl))
8262     warning_at (loc, 0,
8263                 "function declared %<noreturn%> has a %<return%> statement");
8264
8265   if (retval)
8266     {
8267       tree semantic_type = NULL_TREE;
8268       npc = null_pointer_constant_p (retval);
8269       if (TREE_CODE (retval) == EXCESS_PRECISION_EXPR)
8270         {
8271           semantic_type = TREE_TYPE (retval);
8272           retval = TREE_OPERAND (retval, 0);
8273         }
8274       retval = c_fully_fold (retval, false, NULL);
8275       if (semantic_type)
8276         retval = build1 (EXCESS_PRECISION_EXPR, semantic_type, retval);
8277     }
8278
8279   if (!retval)
8280     {
8281       current_function_returns_null = 1;
8282       if ((warn_return_type || flag_isoc99)
8283           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
8284         {
8285           pedwarn_c99 (loc, flag_isoc99 ? 0 : OPT_Wreturn_type,
8286                        "%<return%> with no value, in "
8287                        "function returning non-void");
8288           no_warning = true;
8289         }
8290     }
8291   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
8292     {
8293       current_function_returns_null = 1;
8294       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
8295         pedwarn (loc, 0,
8296                  "%<return%> with a value, in function returning void");
8297       else
8298         pedwarn (loc, OPT_pedantic, "ISO C forbids "
8299                  "%<return%> with expression, in function returning void");
8300     }
8301   else
8302     {
8303       tree t = convert_for_assignment (loc, valtype, retval, origtype,
8304                                        ic_return,
8305                                        npc, NULL_TREE, NULL_TREE, 0);
8306       tree res = DECL_RESULT (current_function_decl);
8307       tree inner;
8308
8309       current_function_returns_value = 1;
8310       if (t == error_mark_node)
8311         return NULL_TREE;
8312
8313       inner = t = convert (TREE_TYPE (res), t);
8314
8315       /* Strip any conversions, additions, and subtractions, and see if
8316          we are returning the address of a local variable.  Warn if so.  */
8317       while (1)
8318         {
8319           switch (TREE_CODE (inner))
8320             {
8321             CASE_CONVERT:
8322             case NON_LVALUE_EXPR:
8323             case PLUS_EXPR:
8324             case POINTER_PLUS_EXPR:
8325               inner = TREE_OPERAND (inner, 0);
8326               continue;
8327
8328             case MINUS_EXPR:
8329               /* If the second operand of the MINUS_EXPR has a pointer
8330                  type (or is converted from it), this may be valid, so
8331                  don't give a warning.  */
8332               {
8333                 tree op1 = TREE_OPERAND (inner, 1);
8334
8335                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
8336                        && (CONVERT_EXPR_P (op1)
8337                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
8338                   op1 = TREE_OPERAND (op1, 0);
8339
8340                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
8341                   break;
8342
8343                 inner = TREE_OPERAND (inner, 0);
8344                 continue;
8345               }
8346
8347             case ADDR_EXPR:
8348               inner = TREE_OPERAND (inner, 0);
8349
8350               while (REFERENCE_CLASS_P (inner)
8351                      && TREE_CODE (inner) != INDIRECT_REF)
8352                 inner = TREE_OPERAND (inner, 0);
8353
8354               if (DECL_P (inner)
8355                   && !DECL_EXTERNAL (inner)
8356                   && !TREE_STATIC (inner)
8357                   && DECL_CONTEXT (inner) == current_function_decl)
8358                 warning_at (loc,
8359                             0, "function returns address of local variable");
8360               break;
8361
8362             default:
8363               break;
8364             }
8365
8366           break;
8367         }
8368
8369       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
8370       SET_EXPR_LOCATION (retval, loc);
8371
8372       if (warn_sequence_point)
8373         verify_sequence_points (retval);
8374     }
8375
8376   ret_stmt = build_stmt (loc, RETURN_EXPR, retval);
8377   TREE_NO_WARNING (ret_stmt) |= no_warning;
8378   return add_stmt (ret_stmt);
8379 }
8380 \f
8381 struct c_switch {
8382   /* The SWITCH_EXPR being built.  */
8383   tree switch_expr;
8384
8385   /* The original type of the testing expression, i.e. before the
8386      default conversion is applied.  */
8387   tree orig_type;
8388
8389   /* A splay-tree mapping the low element of a case range to the high
8390      element, or NULL_TREE if there is no high element.  Used to
8391      determine whether or not a new case label duplicates an old case
8392      label.  We need a tree, rather than simply a hash table, because
8393      of the GNU case range extension.  */
8394   splay_tree cases;
8395
8396   /* The bindings at the point of the switch.  This is used for
8397      warnings crossing decls when branching to a case label.  */
8398   struct c_spot_bindings *bindings;
8399
8400   /* The next node on the stack.  */
8401   struct c_switch *next;
8402 };
8403
8404 /* A stack of the currently active switch statements.  The innermost
8405    switch statement is on the top of the stack.  There is no need to
8406    mark the stack for garbage collection because it is only active
8407    during the processing of the body of a function, and we never
8408    collect at that point.  */
8409
8410 struct c_switch *c_switch_stack;
8411
8412 /* Start a C switch statement, testing expression EXP.  Return the new
8413    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
8414    SWITCH_COND_LOC is the location of the switch's condition.  */
8415
8416 tree
8417 c_start_case (location_t switch_loc,
8418               location_t switch_cond_loc,
8419               tree exp)
8420 {
8421   tree orig_type = error_mark_node;
8422   struct c_switch *cs;
8423
8424   if (exp != error_mark_node)
8425     {
8426       orig_type = TREE_TYPE (exp);
8427
8428       if (!INTEGRAL_TYPE_P (orig_type))
8429         {
8430           if (orig_type != error_mark_node)
8431             {
8432               error_at (switch_cond_loc, "switch quantity not an integer");
8433               orig_type = error_mark_node;
8434             }
8435           exp = integer_zero_node;
8436         }
8437       else
8438         {
8439           tree type = TYPE_MAIN_VARIANT (orig_type);
8440
8441           if (!in_system_header
8442               && (type == long_integer_type_node
8443                   || type == long_unsigned_type_node))
8444             warning_at (switch_cond_loc,
8445                         OPT_Wtraditional, "%<long%> switch expression not "
8446                         "converted to %<int%> in ISO C");
8447
8448           exp = c_fully_fold (exp, false, NULL);
8449           exp = default_conversion (exp);
8450
8451           if (warn_sequence_point)
8452             verify_sequence_points (exp);
8453         }
8454     }
8455
8456   /* Add this new SWITCH_EXPR to the stack.  */
8457   cs = XNEW (struct c_switch);
8458   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
8459   SET_EXPR_LOCATION (cs->switch_expr, switch_loc);
8460   cs->orig_type = orig_type;
8461   cs->cases = splay_tree_new (case_compare, NULL, NULL);
8462   cs->bindings = c_get_switch_bindings ();
8463   cs->next = c_switch_stack;
8464   c_switch_stack = cs;
8465
8466   return add_stmt (cs->switch_expr);
8467 }
8468
8469 /* Process a case label at location LOC.  */
8470
8471 tree
8472 do_case (location_t loc, tree low_value, tree high_value)
8473 {
8474   tree label = NULL_TREE;
8475
8476   if (low_value && TREE_CODE (low_value) != INTEGER_CST)
8477     {
8478       low_value = c_fully_fold (low_value, false, NULL);
8479       if (TREE_CODE (low_value) == INTEGER_CST)
8480         pedwarn (input_location, OPT_pedantic,
8481                  "case label is not an integer constant expression");
8482     }
8483
8484   if (high_value && TREE_CODE (high_value) != INTEGER_CST)
8485     {
8486       high_value = c_fully_fold (high_value, false, NULL);
8487       if (TREE_CODE (high_value) == INTEGER_CST)
8488         pedwarn (input_location, OPT_pedantic,
8489                  "case label is not an integer constant expression");
8490     }
8491
8492   if (c_switch_stack == NULL)
8493     {
8494       if (low_value)
8495         error_at (loc, "case label not within a switch statement");
8496       else
8497         error_at (loc, "%<default%> label not within a switch statement");
8498       return NULL_TREE;
8499     }
8500
8501   if (c_check_switch_jump_warnings (c_switch_stack->bindings,
8502                                     EXPR_LOCATION (c_switch_stack->switch_expr),
8503                                     loc))
8504     return NULL_TREE;
8505
8506   label = c_add_case_label (loc, c_switch_stack->cases,
8507                             SWITCH_COND (c_switch_stack->switch_expr),
8508                             c_switch_stack->orig_type,
8509                             low_value, high_value);
8510   if (label == error_mark_node)
8511     label = NULL_TREE;
8512   return label;
8513 }
8514
8515 /* Finish the switch statement.  */
8516
8517 void
8518 c_finish_case (tree body)
8519 {
8520   struct c_switch *cs = c_switch_stack;
8521   location_t switch_location;
8522
8523   SWITCH_BODY (cs->switch_expr) = body;
8524
8525   /* Emit warnings as needed.  */
8526   switch_location = EXPR_LOCATION (cs->switch_expr);
8527   c_do_switch_warnings (cs->cases, switch_location,
8528                         TREE_TYPE (cs->switch_expr),
8529                         SWITCH_COND (cs->switch_expr));
8530
8531   /* Pop the stack.  */
8532   c_switch_stack = cs->next;
8533   splay_tree_delete (cs->cases);
8534   c_release_switch_bindings (cs->bindings);
8535   XDELETE (cs);
8536 }
8537 \f
8538 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
8539    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
8540    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
8541    statement, and was not surrounded with parenthesis.  */
8542
8543 void
8544 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
8545                   tree else_block, bool nested_if)
8546 {
8547   tree stmt;
8548
8549   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
8550   if (warn_parentheses && nested_if && else_block == NULL)
8551     {
8552       tree inner_if = then_block;
8553
8554       /* We know from the grammar productions that there is an IF nested
8555          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
8556          it might not be exactly THEN_BLOCK, but should be the last
8557          non-container statement within.  */
8558       while (1)
8559         switch (TREE_CODE (inner_if))
8560           {
8561           case COND_EXPR:
8562             goto found;
8563           case BIND_EXPR:
8564             inner_if = BIND_EXPR_BODY (inner_if);
8565             break;
8566           case STATEMENT_LIST:
8567             inner_if = expr_last (then_block);
8568             break;
8569           case TRY_FINALLY_EXPR:
8570           case TRY_CATCH_EXPR:
8571             inner_if = TREE_OPERAND (inner_if, 0);
8572             break;
8573           default:
8574             gcc_unreachable ();
8575           }
8576     found:
8577
8578       if (COND_EXPR_ELSE (inner_if))
8579          warning_at (if_locus, OPT_Wparentheses,
8580                      "suggest explicit braces to avoid ambiguous %<else%>");
8581     }
8582
8583   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
8584   SET_EXPR_LOCATION (stmt, if_locus);
8585   add_stmt (stmt);
8586 }
8587
8588 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
8589    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
8590    is false for DO loops.  INCR is the FOR increment expression.  BODY is
8591    the statement controlled by the loop.  BLAB is the break label.  CLAB is
8592    the continue label.  Everything is allowed to be NULL.  */
8593
8594 void
8595 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
8596                tree blab, tree clab, bool cond_is_first)
8597 {
8598   tree entry = NULL, exit = NULL, t;
8599
8600   /* If the condition is zero don't generate a loop construct.  */
8601   if (cond && integer_zerop (cond))
8602     {
8603       if (cond_is_first)
8604         {
8605           t = build_and_jump (&blab);
8606           SET_EXPR_LOCATION (t, start_locus);
8607           add_stmt (t);
8608         }
8609     }
8610   else
8611     {
8612       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8613
8614       /* If we have an exit condition, then we build an IF with gotos either
8615          out of the loop, or to the top of it.  If there's no exit condition,
8616          then we just build a jump back to the top.  */
8617       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
8618
8619       if (cond && !integer_nonzerop (cond))
8620         {
8621           /* Canonicalize the loop condition to the end.  This means
8622              generating a branch to the loop condition.  Reuse the
8623              continue label, if possible.  */
8624           if (cond_is_first)
8625             {
8626               if (incr || !clab)
8627                 {
8628                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
8629                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
8630                 }
8631               else
8632                 t = build1 (GOTO_EXPR, void_type_node, clab);
8633               SET_EXPR_LOCATION (t, start_locus);
8634               add_stmt (t);
8635             }
8636
8637           t = build_and_jump (&blab);
8638           if (cond_is_first)
8639             exit = fold_build3_loc (start_locus,
8640                                 COND_EXPR, void_type_node, cond, exit, t);
8641           else
8642             exit = fold_build3_loc (input_location,
8643                                 COND_EXPR, void_type_node, cond, exit, t);
8644         }
8645
8646       add_stmt (top);
8647     }
8648
8649   if (body)
8650     add_stmt (body);
8651   if (clab)
8652     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
8653   if (incr)
8654     add_stmt (incr);
8655   if (entry)
8656     add_stmt (entry);
8657   if (exit)
8658     add_stmt (exit);
8659   if (blab)
8660     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
8661 }
8662
8663 tree
8664 c_finish_bc_stmt (location_t loc, tree *label_p, bool is_break)
8665 {
8666   bool skip;
8667   tree label = *label_p;
8668
8669   /* In switch statements break is sometimes stylistically used after
8670      a return statement.  This can lead to spurious warnings about
8671      control reaching the end of a non-void function when it is
8672      inlined.  Note that we are calling block_may_fallthru with
8673      language specific tree nodes; this works because
8674      block_may_fallthru returns true when given something it does not
8675      understand.  */
8676   skip = !block_may_fallthru (cur_stmt_list);
8677
8678   if (!label)
8679     {
8680       if (!skip)
8681         *label_p = label = create_artificial_label (loc);
8682     }
8683   else if (TREE_CODE (label) == LABEL_DECL)
8684     ;
8685   else switch (TREE_INT_CST_LOW (label))
8686     {
8687     case 0:
8688       if (is_break)
8689         error_at (loc, "break statement not within loop or switch");
8690       else
8691         error_at (loc, "continue statement not within a loop");
8692       return NULL_TREE;
8693
8694     case 1:
8695       gcc_assert (is_break);
8696       error_at (loc, "break statement used with OpenMP for loop");
8697       return NULL_TREE;
8698
8699     default:
8700       gcc_unreachable ();
8701     }
8702
8703   if (skip)
8704     return NULL_TREE;
8705
8706   if (!is_break)
8707     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
8708
8709   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
8710 }
8711
8712 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
8713
8714 static void
8715 emit_side_effect_warnings (location_t loc, tree expr)
8716 {
8717   if (expr == error_mark_node)
8718     ;
8719   else if (!TREE_SIDE_EFFECTS (expr))
8720     {
8721       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
8722         warning_at (loc, OPT_Wunused_value, "statement with no effect");
8723     }
8724   else
8725     warn_if_unused_value (expr, loc);
8726 }
8727
8728 /* Process an expression as if it were a complete statement.  Emit
8729    diagnostics, but do not call ADD_STMT.  LOC is the location of the
8730    statement.  */
8731
8732 tree
8733 c_process_expr_stmt (location_t loc, tree expr)
8734 {
8735   if (!expr)
8736     return NULL_TREE;
8737
8738   expr = c_fully_fold (expr, false, NULL);
8739
8740   if (warn_sequence_point)
8741     verify_sequence_points (expr);
8742
8743   if (TREE_TYPE (expr) != error_mark_node
8744       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
8745       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
8746     error_at (loc, "expression statement has incomplete type");
8747
8748   /* If we're not processing a statement expression, warn about unused values.
8749      Warnings for statement expressions will be emitted later, once we figure
8750      out which is the result.  */
8751   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8752       && warn_unused_value)
8753     emit_side_effect_warnings (loc, expr);
8754
8755   /* If the expression is not of a type to which we cannot assign a line
8756      number, wrap the thing in a no-op NOP_EXPR.  */
8757   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
8758     {
8759       expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
8760       SET_EXPR_LOCATION (expr, loc);
8761     }
8762
8763   return expr;
8764 }
8765
8766 /* Emit an expression as a statement.  LOC is the location of the
8767    expression.  */
8768
8769 tree
8770 c_finish_expr_stmt (location_t loc, tree expr)
8771 {
8772   if (expr)
8773     return add_stmt (c_process_expr_stmt (loc, expr));
8774   else
8775     return NULL;
8776 }
8777
8778 /* Do the opposite and emit a statement as an expression.  To begin,
8779    create a new binding level and return it.  */
8780
8781 tree
8782 c_begin_stmt_expr (void)
8783 {
8784   tree ret;
8785
8786   /* We must force a BLOCK for this level so that, if it is not expanded
8787      later, there is a way to turn off the entire subtree of blocks that
8788      are contained in it.  */
8789   keep_next_level ();
8790   ret = c_begin_compound_stmt (true);
8791
8792   c_bindings_start_stmt_expr (c_switch_stack == NULL
8793                               ? NULL
8794                               : c_switch_stack->bindings);
8795
8796   /* Mark the current statement list as belonging to a statement list.  */
8797   STATEMENT_LIST_STMT_EXPR (ret) = 1;
8798
8799   return ret;
8800 }
8801
8802 /* LOC is the location of the compound statement to which this body
8803    belongs.  */
8804
8805 tree
8806 c_finish_stmt_expr (location_t loc, tree body)
8807 {
8808   tree last, type, tmp, val;
8809   tree *last_p;
8810
8811   body = c_end_compound_stmt (loc, body, true);
8812
8813   c_bindings_end_stmt_expr (c_switch_stack == NULL
8814                             ? NULL
8815                             : c_switch_stack->bindings);
8816
8817   /* Locate the last statement in BODY.  See c_end_compound_stmt
8818      about always returning a BIND_EXPR.  */
8819   last_p = &BIND_EXPR_BODY (body);
8820   last = BIND_EXPR_BODY (body);
8821
8822  continue_searching:
8823   if (TREE_CODE (last) == STATEMENT_LIST)
8824     {
8825       tree_stmt_iterator i;
8826
8827       /* This can happen with degenerate cases like ({ }).  No value.  */
8828       if (!TREE_SIDE_EFFECTS (last))
8829         return body;
8830
8831       /* If we're supposed to generate side effects warnings, process
8832          all of the statements except the last.  */
8833       if (warn_unused_value)
8834         {
8835           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
8836             {
8837               location_t tloc;
8838               tree t = tsi_stmt (i);
8839
8840               tloc = EXPR_HAS_LOCATION (t) ? EXPR_LOCATION (t) : loc;
8841               emit_side_effect_warnings (tloc, t);
8842             }
8843         }
8844       else
8845         i = tsi_last (last);
8846       last_p = tsi_stmt_ptr (i);
8847       last = *last_p;
8848     }
8849
8850   /* If the end of the list is exception related, then the list was split
8851      by a call to push_cleanup.  Continue searching.  */
8852   if (TREE_CODE (last) == TRY_FINALLY_EXPR
8853       || TREE_CODE (last) == TRY_CATCH_EXPR)
8854     {
8855       last_p = &TREE_OPERAND (last, 0);
8856       last = *last_p;
8857       goto continue_searching;
8858     }
8859
8860   if (last == error_mark_node)
8861     return last;
8862
8863   /* In the case that the BIND_EXPR is not necessary, return the
8864      expression out from inside it.  */
8865   if (last == BIND_EXPR_BODY (body)
8866       && BIND_EXPR_VARS (body) == NULL)
8867     {
8868       /* Even if this looks constant, do not allow it in a constant
8869          expression.  */
8870       last = c_wrap_maybe_const (last, true);
8871       /* Do not warn if the return value of a statement expression is
8872          unused.  */
8873       TREE_NO_WARNING (last) = 1;
8874       return last;
8875     }
8876
8877   /* Extract the type of said expression.  */
8878   type = TREE_TYPE (last);
8879
8880   /* If we're not returning a value at all, then the BIND_EXPR that
8881      we already have is a fine expression to return.  */
8882   if (!type || VOID_TYPE_P (type))
8883     return body;
8884
8885   /* Now that we've located the expression containing the value, it seems
8886      silly to make voidify_wrapper_expr repeat the process.  Create a
8887      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
8888   tmp = create_tmp_var_raw (type, NULL);
8889
8890   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
8891      tree_expr_nonnegative_p giving up immediately.  */
8892   val = last;
8893   if (TREE_CODE (val) == NOP_EXPR
8894       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
8895     val = TREE_OPERAND (val, 0);
8896
8897   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
8898   SET_EXPR_LOCATION (*last_p, EXPR_LOCATION (last));
8899
8900   {
8901     tree t = build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
8902     SET_EXPR_LOCATION (t, loc);
8903     return t;
8904   }
8905 }
8906 \f
8907 /* Begin and end compound statements.  This is as simple as pushing
8908    and popping new statement lists from the tree.  */
8909
8910 tree
8911 c_begin_compound_stmt (bool do_scope)
8912 {
8913   tree stmt = push_stmt_list ();
8914   if (do_scope)
8915     push_scope ();
8916   return stmt;
8917 }
8918
8919 /* End a compound statement.  STMT is the statement.  LOC is the
8920    location of the compound statement-- this is usually the location
8921    of the opening brace.  */
8922
8923 tree
8924 c_end_compound_stmt (location_t loc, tree stmt, bool do_scope)
8925 {
8926   tree block = NULL;
8927
8928   if (do_scope)
8929     {
8930       if (c_dialect_objc ())
8931         objc_clear_super_receiver ();
8932       block = pop_scope ();
8933     }
8934
8935   stmt = pop_stmt_list (stmt);
8936   stmt = c_build_bind_expr (loc, block, stmt);
8937
8938   /* If this compound statement is nested immediately inside a statement
8939      expression, then force a BIND_EXPR to be created.  Otherwise we'll
8940      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
8941      STATEMENT_LISTs merge, and thus we can lose track of what statement
8942      was really last.  */
8943   if (cur_stmt_list
8944       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
8945       && TREE_CODE (stmt) != BIND_EXPR)
8946     {
8947       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
8948       TREE_SIDE_EFFECTS (stmt) = 1;
8949       SET_EXPR_LOCATION (stmt, loc);
8950     }
8951
8952   return stmt;
8953 }
8954
8955 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
8956    when the current scope is exited.  EH_ONLY is true when this is not
8957    meant to apply to normal control flow transfer.  */
8958
8959 void
8960 push_cleanup (tree decl, tree cleanup, bool eh_only)
8961 {
8962   enum tree_code code;
8963   tree stmt, list;
8964   bool stmt_expr;
8965
8966   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
8967   stmt = build_stmt (DECL_SOURCE_LOCATION (decl), code, NULL, cleanup);
8968   add_stmt (stmt);
8969   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
8970   list = push_stmt_list ();
8971   TREE_OPERAND (stmt, 0) = list;
8972   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
8973 }
8974 \f
8975 /* Build a binary-operation expression without default conversions.
8976    CODE is the kind of expression to build.
8977    LOCATION is the operator's location.
8978    This function differs from `build' in several ways:
8979    the data type of the result is computed and recorded in it,
8980    warnings are generated if arg data types are invalid,
8981    special handling for addition and subtraction of pointers is known,
8982    and some optimization is done (operations on narrow ints
8983    are done in the narrower type when that gives the same result).
8984    Constant folding is also done before the result is returned.
8985
8986    Note that the operands will never have enumeral types, or function
8987    or array types, because either they will have the default conversions
8988    performed or they have both just been converted to some other type in which
8989    the arithmetic is to be done.  */
8990
8991 tree
8992 build_binary_op (location_t location, enum tree_code code,
8993                  tree orig_op0, tree orig_op1, int convert_p)
8994 {
8995   tree type0, type1, orig_type0, orig_type1;
8996   tree eptype;
8997   enum tree_code code0, code1;
8998   tree op0, op1;
8999   tree ret = error_mark_node;
9000   const char *invalid_op_diag;
9001   bool op0_int_operands, op1_int_operands;
9002   bool int_const, int_const_or_overflow, int_operands;
9003
9004   /* Expression code to give to the expression when it is built.
9005      Normally this is CODE, which is what the caller asked for,
9006      but in some special cases we change it.  */
9007   enum tree_code resultcode = code;
9008
9009   /* Data type in which the computation is to be performed.
9010      In the simplest cases this is the common type of the arguments.  */
9011   tree result_type = NULL;
9012
9013   /* When the computation is in excess precision, the type of the
9014      final EXCESS_PRECISION_EXPR.  */
9015   tree real_result_type = NULL;
9016
9017   /* Nonzero means operands have already been type-converted
9018      in whatever way is necessary.
9019      Zero means they need to be converted to RESULT_TYPE.  */
9020   int converted = 0;
9021
9022   /* Nonzero means create the expression with this type, rather than
9023      RESULT_TYPE.  */
9024   tree build_type = 0;
9025
9026   /* Nonzero means after finally constructing the expression
9027      convert it to this type.  */
9028   tree final_type = 0;
9029
9030   /* Nonzero if this is an operation like MIN or MAX which can
9031      safely be computed in short if both args are promoted shorts.
9032      Also implies COMMON.
9033      -1 indicates a bitwise operation; this makes a difference
9034      in the exact conditions for when it is safe to do the operation
9035      in a narrower mode.  */
9036   int shorten = 0;
9037
9038   /* Nonzero if this is a comparison operation;
9039      if both args are promoted shorts, compare the original shorts.
9040      Also implies COMMON.  */
9041   int short_compare = 0;
9042
9043   /* Nonzero if this is a right-shift operation, which can be computed on the
9044      original short and then promoted if the operand is a promoted short.  */
9045   int short_shift = 0;
9046
9047   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
9048   int common = 0;
9049
9050   /* True means types are compatible as far as ObjC is concerned.  */
9051   bool objc_ok;
9052
9053   /* True means this is an arithmetic operation that may need excess
9054      precision.  */
9055   bool may_need_excess_precision;
9056
9057   if (location == UNKNOWN_LOCATION)
9058     location = input_location;
9059
9060   op0 = orig_op0;
9061   op1 = orig_op1;
9062
9063   op0_int_operands = EXPR_INT_CONST_OPERANDS (orig_op0);
9064   if (op0_int_operands)
9065     op0 = remove_c_maybe_const_expr (op0);
9066   op1_int_operands = EXPR_INT_CONST_OPERANDS (orig_op1);
9067   if (op1_int_operands)
9068     op1 = remove_c_maybe_const_expr (op1);
9069   int_operands = (op0_int_operands && op1_int_operands);
9070   if (int_operands)
9071     {
9072       int_const_or_overflow = (TREE_CODE (orig_op0) == INTEGER_CST
9073                                && TREE_CODE (orig_op1) == INTEGER_CST);
9074       int_const = (int_const_or_overflow
9075                    && !TREE_OVERFLOW (orig_op0)
9076                    && !TREE_OVERFLOW (orig_op1));
9077     }
9078   else
9079     int_const = int_const_or_overflow = false;
9080
9081   if (convert_p)
9082     {
9083       op0 = default_conversion (op0);
9084       op1 = default_conversion (op1);
9085     }
9086
9087   orig_type0 = type0 = TREE_TYPE (op0);
9088   orig_type1 = type1 = TREE_TYPE (op1);
9089
9090   /* The expression codes of the data types of the arguments tell us
9091      whether the arguments are integers, floating, pointers, etc.  */
9092   code0 = TREE_CODE (type0);
9093   code1 = TREE_CODE (type1);
9094
9095   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
9096   STRIP_TYPE_NOPS (op0);
9097   STRIP_TYPE_NOPS (op1);
9098
9099   /* If an error was already reported for one of the arguments,
9100      avoid reporting another error.  */
9101
9102   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9103     return error_mark_node;
9104
9105   if ((invalid_op_diag
9106        = targetm.invalid_binary_op (code, type0, type1)))
9107     {
9108       error_at (location, invalid_op_diag);
9109       return error_mark_node;
9110     }
9111
9112   switch (code)
9113     {
9114     case PLUS_EXPR:
9115     case MINUS_EXPR:
9116     case MULT_EXPR:
9117     case TRUNC_DIV_EXPR:
9118     case CEIL_DIV_EXPR:
9119     case FLOOR_DIV_EXPR:
9120     case ROUND_DIV_EXPR:
9121     case EXACT_DIV_EXPR:
9122       may_need_excess_precision = true;
9123       break;
9124     default:
9125       may_need_excess_precision = false;
9126       break;
9127     }
9128   if (TREE_CODE (op0) == EXCESS_PRECISION_EXPR)
9129     {
9130       op0 = TREE_OPERAND (op0, 0);
9131       type0 = TREE_TYPE (op0);
9132     }
9133   else if (may_need_excess_precision
9134            && (eptype = excess_precision_type (type0)) != NULL_TREE)
9135     {
9136       type0 = eptype;
9137       op0 = convert (eptype, op0);
9138     }
9139   if (TREE_CODE (op1) == EXCESS_PRECISION_EXPR)
9140     {
9141       op1 = TREE_OPERAND (op1, 0);
9142       type1 = TREE_TYPE (op1);
9143     }
9144   else if (may_need_excess_precision
9145            && (eptype = excess_precision_type (type1)) != NULL_TREE)
9146     {
9147       type1 = eptype;
9148       op1 = convert (eptype, op1);
9149     }
9150
9151   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
9152
9153   switch (code)
9154     {
9155     case PLUS_EXPR:
9156       /* Handle the pointer + int case.  */
9157       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9158         {
9159           ret = pointer_int_sum (location, PLUS_EXPR, op0, op1);
9160           goto return_build_binary_op;
9161         }
9162       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
9163         {
9164           ret = pointer_int_sum (location, PLUS_EXPR, op1, op0);
9165           goto return_build_binary_op;
9166         }
9167       else
9168         common = 1;
9169       break;
9170
9171     case MINUS_EXPR:
9172       /* Subtraction of two similar pointers.
9173          We must subtract them as integers, then divide by object size.  */
9174       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
9175           && comp_target_types (location, type0, type1))
9176         {
9177           ret = pointer_diff (location, op0, op1);
9178           goto return_build_binary_op;
9179         }
9180       /* Handle pointer minus int.  Just like pointer plus int.  */
9181       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9182         {
9183           ret = pointer_int_sum (location, MINUS_EXPR, op0, op1);
9184           goto return_build_binary_op;
9185         }
9186       else
9187         common = 1;
9188       break;
9189
9190     case MULT_EXPR:
9191       common = 1;
9192       break;
9193
9194     case TRUNC_DIV_EXPR:
9195     case CEIL_DIV_EXPR:
9196     case FLOOR_DIV_EXPR:
9197     case ROUND_DIV_EXPR:
9198     case EXACT_DIV_EXPR:
9199       warn_for_div_by_zero (location, op1);
9200
9201       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9202            || code0 == FIXED_POINT_TYPE
9203            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9204           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9205               || code1 == FIXED_POINT_TYPE
9206               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
9207         {
9208           enum tree_code tcode0 = code0, tcode1 = code1;
9209
9210           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
9211             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
9212           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
9213             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
9214
9215           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
9216               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
9217             resultcode = RDIV_EXPR;
9218           else
9219             /* Although it would be tempting to shorten always here, that
9220                loses on some targets, since the modulo instruction is
9221                undefined if the quotient can't be represented in the
9222                computation mode.  We shorten only if unsigned or if
9223                dividing by something we know != -1.  */
9224             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9225                        || (TREE_CODE (op1) == INTEGER_CST
9226                            && !integer_all_onesp (op1)));
9227           common = 1;
9228         }
9229       break;
9230
9231     case BIT_AND_EXPR:
9232     case BIT_IOR_EXPR:
9233     case BIT_XOR_EXPR:
9234       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9235         shorten = -1;
9236       /* Allow vector types which are not floating point types.   */
9237       else if (code0 == VECTOR_TYPE
9238                && code1 == VECTOR_TYPE
9239                && !VECTOR_FLOAT_TYPE_P (type0)
9240                && !VECTOR_FLOAT_TYPE_P (type1))
9241         common = 1;
9242       break;
9243
9244     case TRUNC_MOD_EXPR:
9245     case FLOOR_MOD_EXPR:
9246       warn_for_div_by_zero (location, op1);
9247
9248       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9249           && TREE_CODE (TREE_TYPE (type0)) == INTEGER_TYPE
9250           && TREE_CODE (TREE_TYPE (type1)) == INTEGER_TYPE)
9251         common = 1;
9252       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
9253         {
9254           /* Although it would be tempting to shorten always here, that loses
9255              on some targets, since the modulo instruction is undefined if the
9256              quotient can't be represented in the computation mode.  We shorten
9257              only if unsigned or if dividing by something we know != -1.  */
9258           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
9259                      || (TREE_CODE (op1) == INTEGER_CST
9260                          && !integer_all_onesp (op1)));
9261           common = 1;
9262         }
9263       break;
9264
9265     case TRUTH_ANDIF_EXPR:
9266     case TRUTH_ORIF_EXPR:
9267     case TRUTH_AND_EXPR:
9268     case TRUTH_OR_EXPR:
9269     case TRUTH_XOR_EXPR:
9270       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
9271            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9272            || code0 == FIXED_POINT_TYPE)
9273           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
9274               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9275               || code1 == FIXED_POINT_TYPE))
9276         {
9277           /* Result of these operations is always an int,
9278              but that does not mean the operands should be
9279              converted to ints!  */
9280           result_type = integer_type_node;
9281           op0 = c_common_truthvalue_conversion (location, op0);
9282           op1 = c_common_truthvalue_conversion (location, op1);
9283           converted = 1;
9284         }
9285       if (code == TRUTH_ANDIF_EXPR)
9286         {
9287           int_const_or_overflow = (int_operands
9288                                    && TREE_CODE (orig_op0) == INTEGER_CST
9289                                    && (op0 == truthvalue_false_node
9290                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9291           int_const = (int_const_or_overflow
9292                        && !TREE_OVERFLOW (orig_op0)
9293                        && (op0 == truthvalue_false_node
9294                            || !TREE_OVERFLOW (orig_op1)));
9295         }
9296       else if (code == TRUTH_ORIF_EXPR)
9297         {
9298           int_const_or_overflow = (int_operands
9299                                    && TREE_CODE (orig_op0) == INTEGER_CST
9300                                    && (op0 == truthvalue_true_node
9301                                        || TREE_CODE (orig_op1) == INTEGER_CST));
9302           int_const = (int_const_or_overflow
9303                        && !TREE_OVERFLOW (orig_op0)
9304                        && (op0 == truthvalue_true_node
9305                            || !TREE_OVERFLOW (orig_op1)));
9306         }
9307       break;
9308
9309       /* Shift operations: result has same type as first operand;
9310          always convert second operand to int.
9311          Also set SHORT_SHIFT if shifting rightward.  */
9312
9313     case RSHIFT_EXPR:
9314       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9315           && code1 == INTEGER_TYPE)
9316         {
9317           if (TREE_CODE (op1) == INTEGER_CST)
9318             {
9319               if (tree_int_cst_sgn (op1) < 0)
9320                 {
9321                   int_const = false;
9322                   if (c_inhibit_evaluation_warnings == 0)
9323                     warning (0, "right shift count is negative");
9324                 }
9325               else
9326                 {
9327                   if (!integer_zerop (op1))
9328                     short_shift = 1;
9329
9330                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9331                     {
9332                       int_const = false;
9333                       if (c_inhibit_evaluation_warnings == 0)
9334                         warning (0, "right shift count >= width of type");
9335                     }
9336                 }
9337             }
9338
9339           /* Use the type of the value to be shifted.  */
9340           result_type = type0;
9341           /* Convert the shift-count to an integer, regardless of size
9342              of value being shifted.  */
9343           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9344             op1 = convert (integer_type_node, op1);
9345           /* Avoid converting op1 to result_type later.  */
9346           converted = 1;
9347         }
9348       break;
9349
9350     case LSHIFT_EXPR:
9351       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
9352           && code1 == INTEGER_TYPE)
9353         {
9354           if (TREE_CODE (op1) == INTEGER_CST)
9355             {
9356               if (tree_int_cst_sgn (op1) < 0)
9357                 {
9358                   int_const = false;
9359                   if (c_inhibit_evaluation_warnings == 0)
9360                     warning (0, "left shift count is negative");
9361                 }
9362
9363               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
9364                 {
9365                   int_const = false;
9366                   if (c_inhibit_evaluation_warnings == 0)
9367                     warning (0, "left shift count >= width of type");
9368                 }
9369             }
9370
9371           /* Use the type of the value to be shifted.  */
9372           result_type = type0;
9373           /* Convert the shift-count to an integer, regardless of size
9374              of value being shifted.  */
9375           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
9376             op1 = convert (integer_type_node, op1);
9377           /* Avoid converting op1 to result_type later.  */
9378           converted = 1;
9379         }
9380       break;
9381
9382     case EQ_EXPR:
9383     case NE_EXPR:
9384       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
9385         warning_at (location,
9386                     OPT_Wfloat_equal,
9387                     "comparing floating point with == or != is unsafe");
9388       /* Result of comparison is always int,
9389          but don't convert the args to int!  */
9390       build_type = integer_type_node;
9391       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9392            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
9393           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9394               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
9395         short_compare = 1;
9396       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9397         {
9398           tree tt0 = TREE_TYPE (type0);
9399           tree tt1 = TREE_TYPE (type1);
9400           addr_space_t as0 = TYPE_ADDR_SPACE (tt0);
9401           addr_space_t as1 = TYPE_ADDR_SPACE (tt1);
9402           addr_space_t as_common = ADDR_SPACE_GENERIC;
9403
9404           /* Anything compares with void *.  void * compares with anything.
9405              Otherwise, the targets must be compatible
9406              and both must be object or both incomplete.  */
9407           if (comp_target_types (location, type0, type1))
9408             result_type = common_pointer_type (type0, type1);
9409           else if (null_pointer_constant_p (orig_op0))
9410             result_type = type1;
9411           else if (null_pointer_constant_p (orig_op1))
9412             result_type = type0;
9413           else if (!addr_space_superset (as0, as1, &as_common))
9414             {
9415               error_at (location, "comparison of pointers to "
9416                         "disjoint address spaces");
9417               return error_mark_node;
9418             }
9419           else if (VOID_TYPE_P (tt0))
9420             {
9421               if (pedantic && TREE_CODE (tt1) == FUNCTION_TYPE)
9422                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9423                          "comparison of %<void *%> with function pointer");
9424             }
9425           else if (VOID_TYPE_P (tt1))
9426             {
9427               if (pedantic && TREE_CODE (tt0) == FUNCTION_TYPE)
9428                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9429                          "comparison of %<void *%> with function pointer");
9430             }
9431           else
9432             /* Avoid warning about the volatile ObjC EH puts on decls.  */
9433             if (!objc_ok)
9434               pedwarn (location, 0,
9435                        "comparison of distinct pointer types lacks a cast");
9436
9437           if (result_type == NULL_TREE)
9438             {
9439               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9440               result_type = build_pointer_type
9441                               (build_qualified_type (void_type_node, qual));
9442             }
9443         }
9444       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9445         {
9446           if (TREE_CODE (op0) == ADDR_EXPR
9447               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
9448             warning_at (location,
9449                         OPT_Waddress, "the address of %qD will never be NULL",
9450                         TREE_OPERAND (op0, 0));
9451           result_type = type0;
9452         }
9453       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9454         {
9455           if (TREE_CODE (op1) == ADDR_EXPR
9456               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
9457             warning_at (location,
9458                         OPT_Waddress, "the address of %qD will never be NULL",
9459                         TREE_OPERAND (op1, 0));
9460           result_type = type1;
9461         }
9462       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9463         {
9464           result_type = type0;
9465           pedwarn (location, 0, "comparison between pointer and integer");
9466         }
9467       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9468         {
9469           result_type = type1;
9470           pedwarn (location, 0, "comparison between pointer and integer");
9471         }
9472       break;
9473
9474     case LE_EXPR:
9475     case GE_EXPR:
9476     case LT_EXPR:
9477     case GT_EXPR:
9478       build_type = integer_type_node;
9479       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
9480            || code0 == FIXED_POINT_TYPE)
9481           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
9482               || code1 == FIXED_POINT_TYPE))
9483         short_compare = 1;
9484       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
9485         {
9486           addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (type0));
9487           addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (type1));
9488           addr_space_t as_common;
9489
9490           if (comp_target_types (location, type0, type1))
9491             {
9492               result_type = common_pointer_type (type0, type1);
9493               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
9494                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
9495                 pedwarn (location, 0,
9496                          "comparison of complete and incomplete pointers");
9497               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
9498                 pedwarn (location, OPT_pedantic, "ISO C forbids "
9499                          "ordered comparisons of pointers to functions");
9500             }
9501           else if (!addr_space_superset (as0, as1, &as_common))
9502             {
9503               error_at (location, "comparison of pointers to "
9504                         "disjoint address spaces");
9505               return error_mark_node;
9506             }
9507           else
9508             {
9509               int qual = ENCODE_QUAL_ADDR_SPACE (as_common);
9510               result_type = build_pointer_type
9511                               (build_qualified_type (void_type_node, qual));
9512               pedwarn (location, 0,
9513                        "comparison of distinct pointer types lacks a cast");
9514             }
9515         }
9516       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
9517         {
9518           result_type = type0;
9519           if (pedantic)
9520             pedwarn (location, OPT_pedantic,
9521                      "ordered comparison of pointer with integer zero");
9522           else if (extra_warnings)
9523             warning_at (location, OPT_Wextra,
9524                      "ordered comparison of pointer with integer zero");
9525         }
9526       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
9527         {
9528           result_type = type1;
9529           pedwarn (location, OPT_pedantic,
9530                    "ordered comparison of pointer with integer zero");
9531         }
9532       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
9533         {
9534           result_type = type0;
9535           pedwarn (location, 0, "comparison between pointer and integer");
9536         }
9537       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
9538         {
9539           result_type = type1;
9540           pedwarn (location, 0, "comparison between pointer and integer");
9541         }
9542       break;
9543
9544     default:
9545       gcc_unreachable ();
9546     }
9547
9548   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
9549     return error_mark_node;
9550
9551   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
9552       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
9553           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
9554                                                     TREE_TYPE (type1))))
9555     {
9556       binary_op_error (location, code, type0, type1);
9557       return error_mark_node;
9558     }
9559
9560   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
9561        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
9562       &&
9563       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
9564        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
9565     {
9566       bool first_complex = (code0 == COMPLEX_TYPE);
9567       bool second_complex = (code1 == COMPLEX_TYPE);
9568       int none_complex = (!first_complex && !second_complex);
9569
9570       if (shorten || common || short_compare)
9571         {
9572           result_type = c_common_type (type0, type1);
9573           if (result_type == error_mark_node)
9574             return error_mark_node;
9575         }
9576
9577       if (first_complex != second_complex
9578           && (code == PLUS_EXPR
9579               || code == MINUS_EXPR
9580               || code == MULT_EXPR
9581               || (code == TRUNC_DIV_EXPR && first_complex))
9582           && TREE_CODE (TREE_TYPE (result_type)) == REAL_TYPE
9583           && flag_signed_zeros)
9584         {
9585           /* An operation on mixed real/complex operands must be
9586              handled specially, but the language-independent code can
9587              more easily optimize the plain complex arithmetic if
9588              -fno-signed-zeros.  */
9589           tree real_type = TREE_TYPE (result_type);
9590           tree real, imag;
9591           if (type0 != orig_type0 || type1 != orig_type1)
9592             {
9593               gcc_assert (may_need_excess_precision && common);
9594               real_result_type = c_common_type (orig_type0, orig_type1);
9595             }
9596           if (first_complex)
9597             {
9598               if (TREE_TYPE (op0) != result_type)
9599                 op0 = convert_and_check (result_type, op0);
9600               if (TREE_TYPE (op1) != real_type)
9601                 op1 = convert_and_check (real_type, op1);
9602             }
9603           else
9604             {
9605               if (TREE_TYPE (op0) != real_type)
9606                 op0 = convert_and_check (real_type, op0);
9607               if (TREE_TYPE (op1) != result_type)
9608                 op1 = convert_and_check (result_type, op1);
9609             }
9610           if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9611             return error_mark_node;
9612           if (first_complex)
9613             {
9614               op0 = c_save_expr (op0);
9615               real = build_unary_op (EXPR_LOCATION (orig_op0), REALPART_EXPR,
9616                                      op0, 1);
9617               imag = build_unary_op (EXPR_LOCATION (orig_op0), IMAGPART_EXPR,
9618                                      op0, 1);
9619               switch (code)
9620                 {
9621                 case MULT_EXPR:
9622                 case TRUNC_DIV_EXPR:
9623                   imag = build2 (resultcode, real_type, imag, op1);
9624                   /* Fall through.  */
9625                 case PLUS_EXPR:
9626                 case MINUS_EXPR:
9627                   real = build2 (resultcode, real_type, real, op1);
9628                   break;
9629                 default:
9630                   gcc_unreachable();
9631                 }
9632             }
9633           else
9634             {
9635               op1 = c_save_expr (op1);
9636               real = build_unary_op (EXPR_LOCATION (orig_op1), REALPART_EXPR,
9637                                      op1, 1);
9638               imag = build_unary_op (EXPR_LOCATION (orig_op1), IMAGPART_EXPR,
9639                                      op1, 1);
9640               switch (code)
9641                 {
9642                 case MULT_EXPR:
9643                   imag = build2 (resultcode, real_type, op0, imag);
9644                   /* Fall through.  */
9645                 case PLUS_EXPR:
9646                   real = build2 (resultcode, real_type, op0, real);
9647                   break;
9648                 case MINUS_EXPR:
9649                   real = build2 (resultcode, real_type, op0, real);
9650                   imag = build1 (NEGATE_EXPR, real_type, imag);
9651                   break;
9652                 default:
9653                   gcc_unreachable();
9654                 }
9655             }
9656           ret = build2 (COMPLEX_EXPR, result_type, real, imag);
9657           goto return_build_binary_op;
9658         }
9659
9660       /* For certain operations (which identify themselves by shorten != 0)
9661          if both args were extended from the same smaller type,
9662          do the arithmetic in that type and then extend.
9663
9664          shorten !=0 and !=1 indicates a bitwise operation.
9665          For them, this optimization is safe only if
9666          both args are zero-extended or both are sign-extended.
9667          Otherwise, we might change the result.
9668          Eg, (short)-1 | (unsigned short)-1 is (int)-1
9669          but calculated in (unsigned short) it would be (unsigned short)-1.  */
9670
9671       if (shorten && none_complex)
9672         {
9673           final_type = result_type;
9674           result_type = shorten_binary_op (result_type, op0, op1,
9675                                            shorten == -1);
9676         }
9677
9678       /* Shifts can be shortened if shifting right.  */
9679
9680       if (short_shift)
9681         {
9682           int unsigned_arg;
9683           tree arg0 = get_narrower (op0, &unsigned_arg);
9684
9685           final_type = result_type;
9686
9687           if (arg0 == op0 && final_type == TREE_TYPE (op0))
9688             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
9689
9690           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
9691               && tree_int_cst_sgn (op1) > 0
9692               /* We can shorten only if the shift count is less than the
9693                  number of bits in the smaller type size.  */
9694               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
9695               /* We cannot drop an unsigned shift after sign-extension.  */
9696               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
9697             {
9698               /* Do an unsigned shift if the operand was zero-extended.  */
9699               result_type
9700                 = c_common_signed_or_unsigned_type (unsigned_arg,
9701                                                     TREE_TYPE (arg0));
9702               /* Convert value-to-be-shifted to that type.  */
9703               if (TREE_TYPE (op0) != result_type)
9704                 op0 = convert (result_type, op0);
9705               converted = 1;
9706             }
9707         }
9708
9709       /* Comparison operations are shortened too but differently.
9710          They identify themselves by setting short_compare = 1.  */
9711
9712       if (short_compare)
9713         {
9714           /* Don't write &op0, etc., because that would prevent op0
9715              from being kept in a register.
9716              Instead, make copies of the our local variables and
9717              pass the copies by reference, then copy them back afterward.  */
9718           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
9719           enum tree_code xresultcode = resultcode;
9720           tree val
9721             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
9722
9723           if (val != 0)
9724             {
9725               ret = val;
9726               goto return_build_binary_op;
9727             }
9728
9729           op0 = xop0, op1 = xop1;
9730           converted = 1;
9731           resultcode = xresultcode;
9732
9733           if (c_inhibit_evaluation_warnings == 0)
9734             {
9735               bool op0_maybe_const = true;
9736               bool op1_maybe_const = true;
9737               tree orig_op0_folded, orig_op1_folded;
9738
9739               if (in_late_binary_op)
9740                 {
9741                   orig_op0_folded = orig_op0;
9742                   orig_op1_folded = orig_op1;
9743                 }
9744               else
9745                 {
9746                   /* Fold for the sake of possible warnings, as in
9747                      build_conditional_expr.  This requires the
9748                      "original" values to be folded, not just op0 and
9749                      op1.  */
9750                   c_inhibit_evaluation_warnings++;
9751                   op0 = c_fully_fold (op0, require_constant_value,
9752                                       &op0_maybe_const);
9753                   op1 = c_fully_fold (op1, require_constant_value,
9754                                       &op1_maybe_const);
9755                   c_inhibit_evaluation_warnings--;
9756                   orig_op0_folded = c_fully_fold (orig_op0,
9757                                                   require_constant_value,
9758                                                   NULL);
9759                   orig_op1_folded = c_fully_fold (orig_op1,
9760                                                   require_constant_value,
9761                                                   NULL);
9762                 }
9763
9764               if (warn_sign_compare)
9765                 warn_for_sign_compare (location, orig_op0_folded,
9766                                        orig_op1_folded, op0, op1,
9767                                        result_type, resultcode);
9768               if (!in_late_binary_op)
9769                 {
9770                   if (!op0_maybe_const || TREE_CODE (op0) != INTEGER_CST)
9771                     op0 = c_wrap_maybe_const (op0, !op0_maybe_const);
9772                   if (!op1_maybe_const || TREE_CODE (op1) != INTEGER_CST)
9773                     op1 = c_wrap_maybe_const (op1, !op1_maybe_const);
9774                 }
9775             }
9776         }
9777     }
9778
9779   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
9780      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
9781      Then the expression will be built.
9782      It will be given type FINAL_TYPE if that is nonzero;
9783      otherwise, it will be given type RESULT_TYPE.  */
9784
9785   if (!result_type)
9786     {
9787       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
9788       return error_mark_node;
9789     }
9790
9791   if (!converted)
9792     {
9793       if (TREE_TYPE (op0) != result_type)
9794         op0 = convert_and_check (result_type, op0);
9795       if (TREE_TYPE (op1) != result_type)
9796         op1 = convert_and_check (result_type, op1);
9797
9798       /* This can happen if one operand has a vector type, and the other
9799          has a different type.  */
9800       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
9801         return error_mark_node;
9802     }
9803
9804   if (build_type == NULL_TREE)
9805     {
9806       build_type = result_type;
9807       if (type0 != orig_type0 || type1 != orig_type1)
9808         {
9809           gcc_assert (may_need_excess_precision && common);
9810           real_result_type = c_common_type (orig_type0, orig_type1);
9811         }
9812     }
9813
9814   /* Treat expressions in initializers specially as they can't trap.  */
9815   if (int_const_or_overflow)
9816     ret = (require_constant_value
9817            ? fold_build2_initializer_loc (location, resultcode, build_type,
9818                                           op0, op1)
9819            : fold_build2_loc (location, resultcode, build_type, op0, op1));
9820   else
9821     ret = build2 (resultcode, build_type, op0, op1);
9822   if (final_type != 0)
9823     ret = convert (final_type, ret);
9824
9825  return_build_binary_op:
9826   gcc_assert (ret != error_mark_node);
9827   if (TREE_CODE (ret) == INTEGER_CST && !TREE_OVERFLOW (ret) && !int_const)
9828     ret = (int_operands
9829            ? note_integer_operands (ret)
9830            : build1 (NOP_EXPR, TREE_TYPE (ret), ret));
9831   else if (TREE_CODE (ret) != INTEGER_CST && int_operands
9832            && !in_late_binary_op)
9833     ret = note_integer_operands (ret);
9834   if (real_result_type)
9835     ret = build1 (EXCESS_PRECISION_EXPR, real_result_type, ret);
9836   protected_set_expr_location (ret, location);
9837   return ret;
9838 }
9839
9840
9841 /* Convert EXPR to be a truth-value, validating its type for this
9842    purpose.  LOCATION is the source location for the expression.  */
9843
9844 tree
9845 c_objc_common_truthvalue_conversion (location_t location, tree expr)
9846 {
9847   bool int_const, int_operands;
9848
9849   switch (TREE_CODE (TREE_TYPE (expr)))
9850     {
9851     case ARRAY_TYPE:
9852       error_at (location, "used array that cannot be converted to pointer where scalar is required");
9853       return error_mark_node;
9854
9855     case RECORD_TYPE:
9856       error_at (location, "used struct type value where scalar is required");
9857       return error_mark_node;
9858
9859     case UNION_TYPE:
9860       error_at (location, "used union type value where scalar is required");
9861       return error_mark_node;
9862
9863     case FUNCTION_TYPE:
9864       gcc_unreachable ();
9865
9866     default:
9867       break;
9868     }
9869
9870   int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr));
9871   int_operands = EXPR_INT_CONST_OPERANDS (expr);
9872   if (int_operands)
9873     expr = remove_c_maybe_const_expr (expr);
9874
9875   /* ??? Should we also give an error for void and vectors rather than
9876      leaving those to give errors later?  */
9877   expr = c_common_truthvalue_conversion (location, expr);
9878
9879   if (TREE_CODE (expr) == INTEGER_CST && int_operands && !int_const)
9880     {
9881       if (TREE_OVERFLOW (expr))
9882         return expr;
9883       else
9884         return note_integer_operands (expr);
9885     }
9886   if (TREE_CODE (expr) == INTEGER_CST && !int_const)
9887     return build1 (NOP_EXPR, TREE_TYPE (expr), expr);
9888   return expr;
9889 }
9890 \f
9891
9892 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
9893    required.  */
9894
9895 tree
9896 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
9897 {
9898   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
9899     {
9900       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
9901       /* Executing a compound literal inside a function reinitializes
9902          it.  */
9903       if (!TREE_STATIC (decl))
9904         *se = true;
9905       return decl;
9906     }
9907   else
9908     return expr;
9909 }
9910 \f
9911 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9912
9913 tree
9914 c_begin_omp_parallel (void)
9915 {
9916   tree block;
9917
9918   keep_next_level ();
9919   block = c_begin_compound_stmt (true);
9920
9921   return block;
9922 }
9923
9924 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound
9925    statement.  LOC is the location of the OMP_PARALLEL.  */
9926
9927 tree
9928 c_finish_omp_parallel (location_t loc, tree clauses, tree block)
9929 {
9930   tree stmt;
9931
9932   block = c_end_compound_stmt (loc, block, true);
9933
9934   stmt = make_node (OMP_PARALLEL);
9935   TREE_TYPE (stmt) = void_type_node;
9936   OMP_PARALLEL_CLAUSES (stmt) = clauses;
9937   OMP_PARALLEL_BODY (stmt) = block;
9938   SET_EXPR_LOCATION (stmt, loc);
9939
9940   return add_stmt (stmt);
9941 }
9942
9943 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
9944
9945 tree
9946 c_begin_omp_task (void)
9947 {
9948   tree block;
9949
9950   keep_next_level ();
9951   block = c_begin_compound_stmt (true);
9952
9953   return block;
9954 }
9955
9956 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound
9957    statement.  LOC is the location of the #pragma.  */
9958
9959 tree
9960 c_finish_omp_task (location_t loc, tree clauses, tree block)
9961 {
9962   tree stmt;
9963
9964   block = c_end_compound_stmt (loc, block, true);
9965
9966   stmt = make_node (OMP_TASK);
9967   TREE_TYPE (stmt) = void_type_node;
9968   OMP_TASK_CLAUSES (stmt) = clauses;
9969   OMP_TASK_BODY (stmt) = block;
9970   SET_EXPR_LOCATION (stmt, loc);
9971
9972   return add_stmt (stmt);
9973 }
9974
9975 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
9976    Remove any elements from the list that are invalid.  */
9977
9978 tree
9979 c_finish_omp_clauses (tree clauses)
9980 {
9981   bitmap_head generic_head, firstprivate_head, lastprivate_head;
9982   tree c, t, *pc = &clauses;
9983   const char *name;
9984
9985   bitmap_obstack_initialize (NULL);
9986   bitmap_initialize (&generic_head, &bitmap_default_obstack);
9987   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
9988   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
9989
9990   for (pc = &clauses, c = clauses; c ; c = *pc)
9991     {
9992       bool remove = false;
9993       bool need_complete = false;
9994       bool need_implicitly_determined = false;
9995
9996       switch (OMP_CLAUSE_CODE (c))
9997         {
9998         case OMP_CLAUSE_SHARED:
9999           name = "shared";
10000           need_implicitly_determined = true;
10001           goto check_dup_generic;
10002
10003         case OMP_CLAUSE_PRIVATE:
10004           name = "private";
10005           need_complete = true;
10006           need_implicitly_determined = true;
10007           goto check_dup_generic;
10008
10009         case OMP_CLAUSE_REDUCTION:
10010           name = "reduction";
10011           need_implicitly_determined = true;
10012           t = OMP_CLAUSE_DECL (c);
10013           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
10014               || POINTER_TYPE_P (TREE_TYPE (t)))
10015             {
10016               error_at (OMP_CLAUSE_LOCATION (c),
10017                         "%qE has invalid type for %<reduction%>", t);
10018               remove = true;
10019             }
10020           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
10021             {
10022               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
10023               const char *r_name = NULL;
10024
10025               switch (r_code)
10026                 {
10027                 case PLUS_EXPR:
10028                 case MULT_EXPR:
10029                 case MINUS_EXPR:
10030                   break;
10031                 case BIT_AND_EXPR:
10032                   r_name = "&";
10033                   break;
10034                 case BIT_XOR_EXPR:
10035                   r_name = "^";
10036                   break;
10037                 case BIT_IOR_EXPR:
10038                   r_name = "|";
10039                   break;
10040                 case TRUTH_ANDIF_EXPR:
10041                   r_name = "&&";
10042                   break;
10043                 case TRUTH_ORIF_EXPR:
10044                   r_name = "||";
10045                   break;
10046                 default:
10047                   gcc_unreachable ();
10048                 }
10049               if (r_name)
10050                 {
10051                   error_at (OMP_CLAUSE_LOCATION (c),
10052                             "%qE has invalid type for %<reduction(%s)%>",
10053                             t, r_name);
10054                   remove = true;
10055                 }
10056             }
10057           goto check_dup_generic;
10058
10059         case OMP_CLAUSE_COPYPRIVATE:
10060           name = "copyprivate";
10061           goto check_dup_generic;
10062
10063         case OMP_CLAUSE_COPYIN:
10064           name = "copyin";
10065           t = OMP_CLAUSE_DECL (c);
10066           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
10067             {
10068               error_at (OMP_CLAUSE_LOCATION (c),
10069                         "%qE must be %<threadprivate%> for %<copyin%>", t);
10070               remove = true;
10071             }
10072           goto check_dup_generic;
10073
10074         check_dup_generic:
10075           t = OMP_CLAUSE_DECL (c);
10076           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10077             {
10078               error_at (OMP_CLAUSE_LOCATION (c),
10079                         "%qE is not a variable in clause %qs", t, name);
10080               remove = true;
10081             }
10082           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10083                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
10084                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10085             {
10086               error_at (OMP_CLAUSE_LOCATION (c),
10087                         "%qE appears more than once in data clauses", t);
10088               remove = true;
10089             }
10090           else
10091             bitmap_set_bit (&generic_head, DECL_UID (t));
10092           break;
10093
10094         case OMP_CLAUSE_FIRSTPRIVATE:
10095           name = "firstprivate";
10096           t = OMP_CLAUSE_DECL (c);
10097           need_complete = true;
10098           need_implicitly_determined = true;
10099           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10100             {
10101               error_at (OMP_CLAUSE_LOCATION (c),
10102                         "%qE is not a variable in clause %<firstprivate%>", t);
10103               remove = true;
10104             }
10105           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10106                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
10107             {
10108               error_at (OMP_CLAUSE_LOCATION (c),
10109                         "%qE appears more than once in data clauses", t);
10110               remove = true;
10111             }
10112           else
10113             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
10114           break;
10115
10116         case OMP_CLAUSE_LASTPRIVATE:
10117           name = "lastprivate";
10118           t = OMP_CLAUSE_DECL (c);
10119           need_complete = true;
10120           need_implicitly_determined = true;
10121           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
10122             {
10123               error_at (OMP_CLAUSE_LOCATION (c),
10124                         "%qE is not a variable in clause %<lastprivate%>", t);
10125               remove = true;
10126             }
10127           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
10128                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
10129             {
10130               error_at (OMP_CLAUSE_LOCATION (c),
10131                      "%qE appears more than once in data clauses", t);
10132               remove = true;
10133             }
10134           else
10135             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
10136           break;
10137
10138         case OMP_CLAUSE_IF:
10139         case OMP_CLAUSE_NUM_THREADS:
10140         case OMP_CLAUSE_SCHEDULE:
10141         case OMP_CLAUSE_NOWAIT:
10142         case OMP_CLAUSE_ORDERED:
10143         case OMP_CLAUSE_DEFAULT:
10144         case OMP_CLAUSE_UNTIED:
10145         case OMP_CLAUSE_COLLAPSE:
10146           pc = &OMP_CLAUSE_CHAIN (c);
10147           continue;
10148
10149         default:
10150           gcc_unreachable ();
10151         }
10152
10153       if (!remove)
10154         {
10155           t = OMP_CLAUSE_DECL (c);
10156
10157           if (need_complete)
10158             {
10159               t = require_complete_type (t);
10160               if (t == error_mark_node)
10161                 remove = true;
10162             }
10163
10164           if (need_implicitly_determined)
10165             {
10166               const char *share_name = NULL;
10167
10168               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
10169                 share_name = "threadprivate";
10170               else switch (c_omp_predetermined_sharing (t))
10171                 {
10172                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
10173                   break;
10174                 case OMP_CLAUSE_DEFAULT_SHARED:
10175                   share_name = "shared";
10176                   break;
10177                 case OMP_CLAUSE_DEFAULT_PRIVATE:
10178                   share_name = "private";
10179                   break;
10180                 default:
10181                   gcc_unreachable ();
10182                 }
10183               if (share_name)
10184                 {
10185                   error_at (OMP_CLAUSE_LOCATION (c),
10186                             "%qE is predetermined %qs for %qs",
10187                             t, share_name, name);
10188                   remove = true;
10189                 }
10190             }
10191         }
10192
10193       if (remove)
10194         *pc = OMP_CLAUSE_CHAIN (c);
10195       else
10196         pc = &OMP_CLAUSE_CHAIN (c);
10197     }
10198
10199   bitmap_obstack_release (NULL);
10200   return clauses;
10201 }
10202
10203 /* Make a variant type in the proper way for C/C++, propagating qualifiers
10204    down to the element type of an array.  */
10205
10206 tree
10207 c_build_qualified_type (tree type, int type_quals)
10208 {
10209   if (type == error_mark_node)
10210     return type;
10211
10212   if (TREE_CODE (type) == ARRAY_TYPE)
10213     {
10214       tree t;
10215       tree element_type = c_build_qualified_type (TREE_TYPE (type),
10216                                                   type_quals);
10217
10218       /* See if we already have an identically qualified type.  */
10219       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
10220         {
10221           if (TYPE_QUALS (strip_array_types (t)) == type_quals
10222               && TYPE_NAME (t) == TYPE_NAME (type)
10223               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
10224               && attribute_list_equal (TYPE_ATTRIBUTES (t),
10225                                        TYPE_ATTRIBUTES (type)))
10226             break;
10227         }
10228       if (!t)
10229         {
10230           tree domain = TYPE_DOMAIN (type);
10231
10232           t = build_variant_type_copy (type);
10233           TREE_TYPE (t) = element_type;
10234
10235           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
10236               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
10237             SET_TYPE_STRUCTURAL_EQUALITY (t);
10238           else if (TYPE_CANONICAL (element_type) != element_type
10239                    || (domain && TYPE_CANONICAL (domain) != domain))
10240             {
10241               tree unqualified_canon
10242                 = build_array_type (TYPE_CANONICAL (element_type),
10243                                     domain? TYPE_CANONICAL (domain)
10244                                           : NULL_TREE);
10245               TYPE_CANONICAL (t)
10246                 = c_build_qualified_type (unqualified_canon, type_quals);
10247             }
10248           else
10249             TYPE_CANONICAL (t) = t;
10250         }
10251       return t;
10252     }
10253
10254   /* A restrict-qualified pointer type must be a pointer to object or
10255      incomplete type.  Note that the use of POINTER_TYPE_P also allows
10256      REFERENCE_TYPEs, which is appropriate for C++.  */
10257   if ((type_quals & TYPE_QUAL_RESTRICT)
10258       && (!POINTER_TYPE_P (type)
10259           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
10260     {
10261       error ("invalid use of %<restrict%>");
10262       type_quals &= ~TYPE_QUAL_RESTRICT;
10263     }
10264
10265   return build_qualified_type (type, type_quals);
10266 }
10267
10268 /* Build a VA_ARG_EXPR for the C parser.  */
10269
10270 tree
10271 c_build_va_arg (location_t loc, tree expr, tree type)
10272 {
10273   if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE)
10274     warning_at (loc, OPT_Wc___compat,
10275                 "C++ requires promoted type, not enum type, in %<va_arg%>");
10276   return build_va_arg (loc, expr, type);
10277 }