gcc/c-typeck.c

   1 /* Build expressions with type checking for C compiler.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_assign,
  53   ic_init,
  54   ic_return
  55 };
  56
  57 /* The level of nesting inside "__alignof__".  */
  58 int in_alignof;
  59
  60 /* The level of nesting inside "sizeof".  */
  61 int in_sizeof;
  62
  63 /* The level of nesting inside "typeof".  */
  64 int in_typeof;
  65
  66 struct c_label_context_se *label_context_stack_se;
  67 struct c_label_context_vm *label_context_stack_vm;
  68
  69 /* Nonzero if we've already printed a "missing braces around initializer"
  70    message within this initializer.  */
  71 static int missing_braces_mentioned;
  72
  73 static int require_constant_value;
  74 static int require_constant_elements;
  75
  76 static bool null_pointer_constant_p (const_tree);
  77 static tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (const_tree, const_tree);
  81 static int type_lists_compatible_p (const_tree, const_tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static int spelling_length (void);
  92 static char *print_spelling (char *);
  93 static void warning_init (int, const char *);
  94 static tree digest_init (tree, tree, bool, int);
  95 static void output_init_element (tree, bool, tree, tree, int);
  96 static void output_pending_init_elements (int);
  97 static int set_designator (int);
  98 static void push_range_stack (tree);
  99 static void add_pending_init (tree, tree);
 100 static void set_nonincremental_init (void);
 101 static void set_nonincremental_init_from_string (tree);
 102 static tree find_init_member (tree);
 103 static void readonly_error (tree, enum lvalue_use);
 104 static int lvalue_or_else (const_tree, enum lvalue_use);
 105 static int lvalue_p (const_tree);
 106 static void record_maybe_used_decl (tree);
 107 static int comptypes_internal (const_tree, const_tree);
 108 \f
 109 /* Return true if EXP is a null pointer constant, false otherwise.  */
 110
 111 static bool
 112 null_pointer_constant_p (const_tree expr)
 113 {
 114   /* This should really operate on c_expr structures, but they aren't
 115      yet available everywhere required.  */
 116   tree type = TREE_TYPE (expr);
 117   return (TREE_CODE (expr) == INTEGER_CST
 118           && !TREE_OVERFLOW (expr)
 119           && integer_zerop (expr)
 120           && (INTEGRAL_TYPE_P (type)
 121               || (TREE_CODE (type) == POINTER_TYPE
 122                   && VOID_TYPE_P (TREE_TYPE (type))
 123                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 124 }
 125 \f/* This is a cache to hold if two types are compatible or not.  */
 126
 127 struct tagged_tu_seen_cache {
 128   const struct tagged_tu_seen_cache * next;
 129   const_tree t1;
 130   const_tree t2;
 131   /* The return value of tagged_types_tu_compatible_p if we had seen
 132      these two types already.  */
 133   int val;
 134 };
 135
 136 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 137 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 138
 139 /* Do `exp = require_complete_type (exp);' to make sure exp
 140    does not have an incomplete type.  (That includes void types.)  */
 141
 142 tree
 143 require_complete_type (tree value)
 144 {
 145   tree type = TREE_TYPE (value);
 146
 147   if (value == error_mark_node || type == error_mark_node)
 148     return error_mark_node;
 149
 150   /* First, detect a valid value with a complete type.  */
 151   if (COMPLETE_TYPE_P (type))
 152     return value;
 153
 154   c_incomplete_type_error (value, type);
 155   return error_mark_node;
 156 }
 157
 158 /* Print an error message for invalid use of an incomplete type.
 159    VALUE is the expression that was used (or 0 if that isn't known)
 160    and TYPE is the type that was invalid.  */
 161
 162 void
 163 c_incomplete_type_error (const_tree value, const_tree type)
 164 {
 165   const char *type_code_string;
 166
 167   /* Avoid duplicate error message.  */
 168   if (TREE_CODE (type) == ERROR_MARK)
 169     return;
 170
 171   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 172                      || TREE_CODE (value) == PARM_DECL))
 173     error ("%qD has an incomplete type", value);
 174   else
 175     {
 176     retry:
 177       /* We must print an error message.  Be clever about what it says.  */
 178
 179       switch (TREE_CODE (type))
 180         {
 181         case RECORD_TYPE:
 182           type_code_string = "struct";
 183           break;
 184
 185         case UNION_TYPE:
 186           type_code_string = "union";
 187           break;
 188
 189         case ENUMERAL_TYPE:
 190           type_code_string = "enum";
 191           break;
 192
 193         case VOID_TYPE:
 194           error ("invalid use of void expression");
 195           return;
 196
 197         case ARRAY_TYPE:
 198           if (TYPE_DOMAIN (type))
 199             {
 200               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 201                 {
 202                   error ("invalid use of flexible array member");
 203                   return;
 204                 }
 205               type = TREE_TYPE (type);
 206               goto retry;
 207             }
 208           error ("invalid use of array with unspecified bounds");
 209           return;
 210
 211         default:
 212           gcc_unreachable ();
 213         }
 214
 215       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 216         error ("invalid use of undefined type %<%s %E%>",
 217                type_code_string, TYPE_NAME (type));
 218       else
 219         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 220         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 221     }
 222 }
 223
 224 /* Given a type, apply default promotions wrt unnamed function
 225    arguments and return the new type.  */
 226
 227 tree
 228 c_type_promotes_to (tree type)
 229 {
 230   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 231     return double_type_node;
 232
 233   if (c_promoting_integer_type_p (type))
 234     {
 235       /* Preserve unsignedness if not really getting any wider.  */
 236       if (TYPE_UNSIGNED (type)
 237           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 238         return unsigned_type_node;
 239       return integer_type_node;
 240     }
 241
 242   return type;
 243 }
 244
 245 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 246    as well as those of TYPE.  */
 247
 248 static tree
 249 qualify_type (tree type, tree like)
 250 {
 251   return c_build_qualified_type (type,
 252                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 253 }
 254
 255 /* Return true iff the given tree T is a variable length array.  */
 256
 257 bool
 258 c_vla_type_p (const_tree t)
 259 {
 260   if (TREE_CODE (t) == ARRAY_TYPE
 261       && C_TYPE_VARIABLE_SIZE (t))
 262     return true;
 263   return false;
 264 }
 265 \f
 266 /* Return the composite type of two compatible types.
 267
 268    We assume that comptypes has already been done and returned
 269    nonzero; if that isn't so, this may crash.  In particular, we
 270    assume that qualifiers match.  */
 271
 272 tree
 273 composite_type (tree t1, tree t2)
 274 {
 275   enum tree_code code1;
 276   enum tree_code code2;
 277   tree attributes;
 278
 279   /* Save time if the two types are the same.  */
 280
 281   if (t1 == t2) return t1;
 282
 283   /* If one type is nonsense, use the other.  */
 284   if (t1 == error_mark_node)
 285     return t2;
 286   if (t2 == error_mark_node)
 287     return t1;
 288
 289   code1 = TREE_CODE (t1);
 290   code2 = TREE_CODE (t2);
 291
 292   /* Merge the attributes.  */
 293   attributes = targetm.merge_type_attributes (t1, t2);
 294
 295   /* If one is an enumerated type and the other is the compatible
 296      integer type, the composite type might be either of the two
 297      (DR#013 question 3).  For consistency, use the enumerated type as
 298      the composite type.  */
 299
 300   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 301     return t1;
 302   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 303     return t2;
 304
 305   gcc_assert (code1 == code2);
 306
 307   switch (code1)
 308     {
 309     case POINTER_TYPE:
 310       /* For two pointers, do this recursively on the target type.  */
 311       {
 312         tree pointed_to_1 = TREE_TYPE (t1);
 313         tree pointed_to_2 = TREE_TYPE (t2);
 314         tree target = composite_type (pointed_to_1, pointed_to_2);
 315         t1 = build_pointer_type (target);
 316         t1 = build_type_attribute_variant (t1, attributes);
 317         return qualify_type (t1, t2);
 318       }
 319
 320     case ARRAY_TYPE:
 321       {
 322         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 323         int quals;
 324         tree unqual_elt;
 325         tree d1 = TYPE_DOMAIN (t1);
 326         tree d2 = TYPE_DOMAIN (t2);
 327         bool d1_variable, d2_variable;
 328         bool d1_zero, d2_zero;
 329
 330         /* We should not have any type quals on arrays at all.  */
 331         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 332
 333         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 334         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 335
 336         d1_variable = (!d1_zero
 337                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 338                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 339         d2_variable = (!d2_zero
 340                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 341                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 342         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 343         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 344
 345         /* Save space: see if the result is identical to one of the args.  */
 346         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 347             && (d2_variable || d2_zero || !d1_variable))
 348           return build_type_attribute_variant (t1, attributes);
 349         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 350             && (d1_variable || d1_zero || !d2_variable))
 351           return build_type_attribute_variant (t2, attributes);
 352
 353         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 354           return build_type_attribute_variant (t1, attributes);
 355         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 356           return build_type_attribute_variant (t2, attributes);
 357
 358         /* Merge the element types, and have a size if either arg has
 359            one.  We may have qualifiers on the element types.  To set
 360            up TYPE_MAIN_VARIANT correctly, we need to form the
 361            composite of the unqualified types and add the qualifiers
 362            back at the end.  */
 363         quals = TYPE_QUALS (strip_array_types (elt));
 364         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 365         t1 = build_array_type (unqual_elt,
 366                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 367                                              && (d2_variable
 368                                                  || d2_zero
 369                                                  || !d1_variable))
 370                                             ? t1
 371                                             : t2));
 372         t1 = c_build_qualified_type (t1, quals);
 373         return build_type_attribute_variant (t1, attributes);
 374       }
 375
 376     case ENUMERAL_TYPE:
 377     case RECORD_TYPE:
 378     case UNION_TYPE:
 379       if (attributes != NULL)
 380         {
 381           /* Try harder not to create a new aggregate type.  */
 382           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 383             return t1;
 384           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 385             return t2;
 386         }
 387       return build_type_attribute_variant (t1, attributes);
 388
 389     case FUNCTION_TYPE:
 390       /* Function types: prefer the one that specified arg types.
 391          If both do, merge the arg types.  Also merge the return types.  */
 392       {
 393         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 394         tree p1 = TYPE_ARG_TYPES (t1);
 395         tree p2 = TYPE_ARG_TYPES (t2);
 396         int len;
 397         tree newargs, n;
 398         int i;
 399
 400         /* Save space: see if the result is identical to one of the args.  */
 401         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 402           return build_type_attribute_variant (t1, attributes);
 403         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 404           return build_type_attribute_variant (t2, attributes);
 405
 406         /* Simple way if one arg fails to specify argument types.  */
 407         if (TYPE_ARG_TYPES (t1) == 0)
 408          {
 409             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 410             t1 = build_type_attribute_variant (t1, attributes);
 411             return qualify_type (t1, t2);
 412          }
 413         if (TYPE_ARG_TYPES (t2) == 0)
 414          {
 415            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 416            t1 = build_type_attribute_variant (t1, attributes);
 417            return qualify_type (t1, t2);
 418          }
 419
 420         /* If both args specify argument types, we must merge the two
 421            lists, argument by argument.  */
 422         /* Tell global_bindings_p to return false so that variable_size
 423            doesn't die on VLAs in parameter types.  */
 424         c_override_global_bindings_to_false = true;
 425
 426         len = list_length (p1);
 427         newargs = 0;
 428
 429         for (i = 0; i < len; i++)
 430           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 431
 432         n = newargs;
 433
 434         for (; p1;
 435              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 436           {
 437             /* A null type means arg type is not specified.
 438                Take whatever the other function type has.  */
 439             if (TREE_VALUE (p1) == 0)
 440               {
 441                 TREE_VALUE (n) = TREE_VALUE (p2);
 442                 goto parm_done;
 443               }
 444             if (TREE_VALUE (p2) == 0)
 445               {
 446                 TREE_VALUE (n) = TREE_VALUE (p1);
 447                 goto parm_done;
 448               }
 449
 450             /* Given  wait (union {union wait *u; int *i} *)
 451                and  wait (union wait *),
 452                prefer  union wait *  as type of parm.  */
 453             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 454                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 455               {
 456                 tree memb;
 457                 tree mv2 = TREE_VALUE (p2);
 458                 if (mv2 && mv2 != error_mark_node
 459                     && TREE_CODE (mv2) != ARRAY_TYPE)
 460                   mv2 = TYPE_MAIN_VARIANT (mv2);
 461                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 462                      memb; memb = TREE_CHAIN (memb))
 463                   {
 464                     tree mv3 = TREE_TYPE (memb);
 465                     if (mv3 && mv3 != error_mark_node
 466                         && TREE_CODE (mv3) != ARRAY_TYPE)
 467                       mv3 = TYPE_MAIN_VARIANT (mv3);
 468                     if (comptypes (mv3, mv2))
 469                       {
 470                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 471                                                          TREE_VALUE (p2));
 472                         pedwarn (input_location, OPT_pedantic,
 473                                  "function types not truly compatible in ISO C");
 474                         goto parm_done;
 475                       }
 476                   }
 477               }
 478             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 479                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 480               {
 481                 tree memb;
 482                 tree mv1 = TREE_VALUE (p1);
 483                 if (mv1 && mv1 != error_mark_node
 484                     && TREE_CODE (mv1) != ARRAY_TYPE)
 485                   mv1 = TYPE_MAIN_VARIANT (mv1);
 486                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 487                      memb; memb = TREE_CHAIN (memb))
 488                   {
 489                     tree mv3 = TREE_TYPE (memb);
 490                     if (mv3 && mv3 != error_mark_node
 491                         && TREE_CODE (mv3) != ARRAY_TYPE)
 492                       mv3 = TYPE_MAIN_VARIANT (mv3);
 493                     if (comptypes (mv3, mv1))
 494                       {
 495                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 496                                                          TREE_VALUE (p1));
 497                         pedwarn (input_location, OPT_pedantic,
 498                                  "function types not truly compatible in ISO C");
 499                         goto parm_done;
 500                       }
 501                   }
 502               }
 503             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 504           parm_done: ;
 505           }
 506
 507         c_override_global_bindings_to_false = false;
 508         t1 = build_function_type (valtype, newargs);
 509         t1 = qualify_type (t1, t2);
 510         /* ... falls through ...  */
 511       }
 512
 513     default:
 514       return build_type_attribute_variant (t1, attributes);
 515     }
 516
 517 }
 518
 519 /* Return the type of a conditional expression between pointers to
 520    possibly differently qualified versions of compatible types.
 521
 522    We assume that comp_target_types has already been done and returned
 523    nonzero; if that isn't so, this may crash.  */
 524
 525 static tree
 526 common_pointer_type (tree t1, tree t2)
 527 {
 528   tree attributes;
 529   tree pointed_to_1, mv1;
 530   tree pointed_to_2, mv2;
 531   tree target;
 532   unsigned target_quals;
 533
 534   /* Save time if the two types are the same.  */
 535
 536   if (t1 == t2) return t1;
 537
 538   /* If one type is nonsense, use the other.  */
 539   if (t1 == error_mark_node)
 540     return t2;
 541   if (t2 == error_mark_node)
 542     return t1;
 543
 544   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 545               && TREE_CODE (t2) == POINTER_TYPE);
 546
 547   /* Merge the attributes.  */
 548   attributes = targetm.merge_type_attributes (t1, t2);
 549
 550   /* Find the composite type of the target types, and combine the
 551      qualifiers of the two types' targets.  Do not lose qualifiers on
 552      array element types by taking the TYPE_MAIN_VARIANT.  */
 553   mv1 = pointed_to_1 = TREE_TYPE (t1);
 554   mv2 = pointed_to_2 = TREE_TYPE (t2);
 555   if (TREE_CODE (mv1) != ARRAY_TYPE)
 556     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 557   if (TREE_CODE (mv2) != ARRAY_TYPE)
 558     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 559   target = composite_type (mv1, mv2);
 560
 561   /* For function types do not merge const qualifiers, but drop them
 562      if used inconsistently.  The middle-end uses these to mark const
 563      and noreturn functions.  */
 564   if (TREE_CODE (pointed_to_1) == FUNCTION_TYPE)
 565     target_quals = TYPE_QUALS (pointed_to_1) & TYPE_QUALS (pointed_to_2);
 566   else
 567     target_quals = TYPE_QUALS (pointed_to_1) | TYPE_QUALS (pointed_to_2);
 568   t1 = build_pointer_type (c_build_qualified_type (target, target_quals));
 569   return build_type_attribute_variant (t1, attributes);
 570 }
 571
 572 /* Return the common type for two arithmetic types under the usual
 573    arithmetic conversions.  The default conversions have already been
 574    applied, and enumerated types converted to their compatible integer
 575    types.  The resulting type is unqualified and has no attributes.
 576
 577    This is the type for the result of most arithmetic operations
 578    if the operands have the given two types.  */
 579
 580 static tree
 581 c_common_type (tree t1, tree t2)
 582 {
 583   enum tree_code code1;
 584   enum tree_code code2;
 585
 586   /* If one type is nonsense, use the other.  */
 587   if (t1 == error_mark_node)
 588     return t2;
 589   if (t2 == error_mark_node)
 590     return t1;
 591
 592   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 593     t1 = TYPE_MAIN_VARIANT (t1);
 594
 595   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 596     t2 = TYPE_MAIN_VARIANT (t2);
 597
 598   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 599     t1 = build_type_attribute_variant (t1, NULL_TREE);
 600
 601   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 602     t2 = build_type_attribute_variant (t2, NULL_TREE);
 603
 604   /* Save time if the two types are the same.  */
 605
 606   if (t1 == t2) return t1;
 607
 608   code1 = TREE_CODE (t1);
 609   code2 = TREE_CODE (t2);
 610
 611   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 612               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 613               || code1 == INTEGER_TYPE);
 614   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 615               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 616               || code2 == INTEGER_TYPE);
 617
 618   /* When one operand is a decimal float type, the other operand cannot be
 619      a generic float type or a complex type.  We also disallow vector types
 620      here.  */
 621   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 622       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 623     {
 624       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 625         {
 626           error ("can%'t mix operands of decimal float and vector types");
 627           return error_mark_node;
 628         }
 629       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 630         {
 631           error ("can%'t mix operands of decimal float and complex types");
 632           return error_mark_node;
 633         }
 634       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 635         {
 636           error ("can%'t mix operands of decimal float and other float types");
 637           return error_mark_node;
 638         }
 639     }
 640
 641   /* If one type is a vector type, return that type.  (How the usual
 642      arithmetic conversions apply to the vector types extension is not
 643      precisely specified.)  */
 644   if (code1 == VECTOR_TYPE)
 645     return t1;
 646
 647   if (code2 == VECTOR_TYPE)
 648     return t2;
 649
 650   /* If one type is complex, form the common type of the non-complex
 651      components, then make that complex.  Use T1 or T2 if it is the
 652      required type.  */
 653   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 654     {
 655       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 656       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 657       tree subtype = c_common_type (subtype1, subtype2);
 658
 659       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 660         return t1;
 661       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 662         return t2;
 663       else
 664         return build_complex_type (subtype);
 665     }
 666
 667   /* If only one is real, use it as the result.  */
 668
 669   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 670     return t1;
 671
 672   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 673     return t2;
 674
 675   /* If both are real and either are decimal floating point types, use
 676      the decimal floating point type with the greater precision. */
 677
 678   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 679     {
 680       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 681           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 682         return dfloat128_type_node;
 683       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 684                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 685         return dfloat64_type_node;
 686       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 687                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 688         return dfloat32_type_node;
 689     }
 690
 691   /* Deal with fixed-point types.  */
 692   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 693     {
 694       unsigned int unsignedp = 0, satp = 0;
 695       enum machine_mode m1, m2;
 696       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 697
 698       m1 = TYPE_MODE (t1);
 699       m2 = TYPE_MODE (t2);
 700
 701       /* If one input type is saturating, the result type is saturating.  */
 702       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 703         satp = 1;
 704
 705       /* If both fixed-point types are unsigned, the result type is unsigned.
 706          When mixing fixed-point and integer types, follow the sign of the
 707          fixed-point type.
 708          Otherwise, the result type is signed.  */
 709       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 710            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 711           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 712               && TYPE_UNSIGNED (t1))
 713           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 714               && TYPE_UNSIGNED (t2)))
 715         unsignedp = 1;
 716
 717       /* The result type is signed.  */
 718       if (unsignedp == 0)
 719         {
 720           /* If the input type is unsigned, we need to convert to the
 721              signed type.  */
 722           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 723             {
 724               enum mode_class mclass = (enum mode_class) 0;
 725               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 726                 mclass = MODE_FRACT;
 727               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 728                 mclass = MODE_ACCUM;
 729               else
 730                 gcc_unreachable ();
 731               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 732             }
 733           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 734             {
 735               enum mode_class mclass = (enum mode_class) 0;
 736               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 737                 mclass = MODE_FRACT;
 738               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 739                 mclass = MODE_ACCUM;
 740               else
 741                 gcc_unreachable ();
 742               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 743             }
 744         }
 745
 746       if (code1 == FIXED_POINT_TYPE)
 747         {
 748           fbit1 = GET_MODE_FBIT (m1);
 749           ibit1 = GET_MODE_IBIT (m1);
 750         }
 751       else
 752         {
 753           fbit1 = 0;
 754           /* Signed integers need to subtract one sign bit.  */
 755           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 756         }
 757
 758       if (code2 == FIXED_POINT_TYPE)
 759         {
 760           fbit2 = GET_MODE_FBIT (m2);
 761           ibit2 = GET_MODE_IBIT (m2);
 762         }
 763       else
 764         {
 765           fbit2 = 0;
 766           /* Signed integers need to subtract one sign bit.  */
 767           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 768         }
 769
 770       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 771       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 772       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 773                                                  satp);
 774     }
 775
 776   /* Both real or both integers; use the one with greater precision.  */
 777
 778   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 779     return t1;
 780   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 781     return t2;
 782
 783   /* Same precision.  Prefer long longs to longs to ints when the
 784      same precision, following the C99 rules on integer type rank
 785      (which are equivalent to the C90 rules for C90 types).  */
 786
 787   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 788       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 789     return long_long_unsigned_type_node;
 790
 791   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 792       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 793     {
 794       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 795         return long_long_unsigned_type_node;
 796       else
 797         return long_long_integer_type_node;
 798     }
 799
 800   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 801       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 802     return long_unsigned_type_node;
 803
 804   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 805       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 806     {
 807       /* But preserve unsignedness from the other type,
 808          since long cannot hold all the values of an unsigned int.  */
 809       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 810         return long_unsigned_type_node;
 811       else
 812         return long_integer_type_node;
 813     }
 814
 815   /* Likewise, prefer long double to double even if same size.  */
 816   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 817       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 818     return long_double_type_node;
 819
 820   /* Otherwise prefer the unsigned one.  */
 821
 822   if (TYPE_UNSIGNED (t1))
 823     return t1;
 824   else
 825     return t2;
 826 }
 827 \f
 828 /* Wrapper around c_common_type that is used by c-common.c and other
 829    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 830    are allowed here and are converted to their compatible integer types.
 831    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 832    preferably a non-Boolean type as the common type.  */
 833 tree
 834 common_type (tree t1, tree t2)
 835 {
 836   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 837     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 838   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 839     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 840
 841   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 842   if (TREE_CODE (t1) == BOOLEAN_TYPE
 843       && TREE_CODE (t2) == BOOLEAN_TYPE)
 844     return boolean_type_node;
 845
 846   /* If either type is BOOLEAN_TYPE, then return the other.  */
 847   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 848     return t2;
 849   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 850     return t1;
 851
 852   return c_common_type (t1, t2);
 853 }
 854
 855 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 856    or various other operations.  Return 2 if they are compatible
 857    but a warning may be needed if you use them together.  */
 858
 859 int
 860 comptypes (tree type1, tree type2)
 861 {
 862   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 863   int val;
 864
 865   val = comptypes_internal (type1, type2);
 866   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 867
 868   return val;
 869 }
 870 \f
 871 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 872    or various other operations.  Return 2 if they are compatible
 873    but a warning may be needed if you use them together.  This
 874    differs from comptypes, in that we don't free the seen types.  */
 875
 876 static int
 877 comptypes_internal (const_tree type1, const_tree type2)
 878 {
 879   const_tree t1 = type1;
 880   const_tree t2 = type2;
 881   int attrval, val;
 882
 883   /* Suppress errors caused by previously reported errors.  */
 884
 885   if (t1 == t2 || !t1 || !t2
 886       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 887     return 1;
 888
 889   /* If either type is the internal version of sizetype, return the
 890      language version.  */
 891   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 892       && TYPE_ORIG_SIZE_TYPE (t1))
 893     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 894
 895   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 896       && TYPE_ORIG_SIZE_TYPE (t2))
 897     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 898
 899
 900   /* Enumerated types are compatible with integer types, but this is
 901      not transitive: two enumerated types in the same translation unit
 902      are compatible with each other only if they are the same type.  */
 903
 904   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 905     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 906   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 907     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 908
 909   if (t1 == t2)
 910     return 1;
 911
 912   /* Different classes of types can't be compatible.  */
 913
 914   if (TREE_CODE (t1) != TREE_CODE (t2))
 915     return 0;
 916
 917   /* Qualifiers must match. C99 6.7.3p9 */
 918
 919   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 920     return 0;
 921
 922   /* Allow for two different type nodes which have essentially the same
 923      definition.  Note that we already checked for equality of the type
 924      qualifiers (just above).  */
 925
 926   if (TREE_CODE (t1) != ARRAY_TYPE
 927       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 928     return 1;
 929
 930   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 931   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 932      return 0;
 933
 934   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 935   val = 0;
 936
 937   switch (TREE_CODE (t1))
 938     {
 939     case POINTER_TYPE:
 940       /* Do not remove mode or aliasing information.  */
 941       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 942           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 943         break;
 944       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 945              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 946       break;
 947
 948     case FUNCTION_TYPE:
 949       val = function_types_compatible_p (t1, t2);
 950       break;
 951
 952     case ARRAY_TYPE:
 953       {
 954         tree d1 = TYPE_DOMAIN (t1);
 955         tree d2 = TYPE_DOMAIN (t2);
 956         bool d1_variable, d2_variable;
 957         bool d1_zero, d2_zero;
 958         val = 1;
 959
 960         /* Target types must match incl. qualifiers.  */
 961         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 962             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 963           return 0;
 964
 965         /* Sizes must match unless one is missing or variable.  */
 966         if (d1 == 0 || d2 == 0 || d1 == d2)
 967           break;
 968
 969         d1_zero = !TYPE_MAX_VALUE (d1);
 970         d2_zero = !TYPE_MAX_VALUE (d2);
 971
 972         d1_variable = (!d1_zero
 973                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 974                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 975         d2_variable = (!d2_zero
 976                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 977                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 978         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 979         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 980
 981         if (d1_variable || d2_variable)
 982           break;
 983         if (d1_zero && d2_zero)
 984           break;
 985         if (d1_zero || d2_zero
 986             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 987             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 988           val = 0;
 989
 990         break;
 991       }
 992
 993     case ENUMERAL_TYPE:
 994     case RECORD_TYPE:
 995     case UNION_TYPE:
 996       if (val != 1 && !same_translation_unit_p (t1, t2))
 997         {
 998           tree a1 = TYPE_ATTRIBUTES (t1);
 999           tree a2 = TYPE_ATTRIBUTES (t2);
1000
1001           if (! attribute_list_contained (a1, a2)
1002               && ! attribute_list_contained (a2, a1))
1003             break;
1004
1005           if (attrval != 2)
1006             return tagged_types_tu_compatible_p (t1, t2);
1007           val = tagged_types_tu_compatible_p (t1, t2);
1008         }
1009       break;
1010
1011     case VECTOR_TYPE:
1012       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1013             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1014       break;
1015
1016     default:
1017       break;
1018     }
1019   return attrval == 2 && val == 1 ? 2 : val;
1020 }
1021
1022 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1023    ignoring their qualifiers.  */
1024
1025 static int
1026 comp_target_types (tree ttl, tree ttr)
1027 {
1028   int val;
1029   tree mvl, mvr;
1030
1031   /* Do not lose qualifiers on element types of array types that are
1032      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1033   mvl = TREE_TYPE (ttl);
1034   mvr = TREE_TYPE (ttr);
1035   if (TREE_CODE (mvl) != ARRAY_TYPE)
1036     mvl = TYPE_MAIN_VARIANT (mvl);
1037   if (TREE_CODE (mvr) != ARRAY_TYPE)
1038     mvr = TYPE_MAIN_VARIANT (mvr);
1039   val = comptypes (mvl, mvr);
1040
1041   if (val == 2)
1042     pedwarn (input_location, OPT_pedantic, "types are not quite compatible");
1043   return val;
1044 }
1045 \f
1046 /* Subroutines of `comptypes'.  */
1047
1048 /* Determine whether two trees derive from the same translation unit.
1049    If the CONTEXT chain ends in a null, that tree's context is still
1050    being parsed, so if two trees have context chains ending in null,
1051    they're in the same translation unit.  */
1052 int
1053 same_translation_unit_p (const_tree t1, const_tree t2)
1054 {
1055   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1056     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1057       {
1058       case tcc_declaration:
1059         t1 = DECL_CONTEXT (t1); break;
1060       case tcc_type:
1061         t1 = TYPE_CONTEXT (t1); break;
1062       case tcc_exceptional:
1063         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1064       default: gcc_unreachable ();
1065       }
1066
1067   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1068     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1069       {
1070       case tcc_declaration:
1071         t2 = DECL_CONTEXT (t2); break;
1072       case tcc_type:
1073         t2 = TYPE_CONTEXT (t2); break;
1074       case tcc_exceptional:
1075         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1076       default: gcc_unreachable ();
1077       }
1078
1079   return t1 == t2;
1080 }
1081
1082 /* Allocate the seen two types, assuming that they are compatible. */
1083
1084 static struct tagged_tu_seen_cache *
1085 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1086 {
1087   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1088   tu->next = tagged_tu_seen_base;
1089   tu->t1 = t1;
1090   tu->t2 = t2;
1091
1092   tagged_tu_seen_base = tu;
1093
1094   /* The C standard says that two structures in different translation
1095      units are compatible with each other only if the types of their
1096      fields are compatible (among other things).  We assume that they
1097      are compatible until proven otherwise when building the cache.
1098      An example where this can occur is:
1099      struct a
1100      {
1101        struct a *next;
1102      };
1103      If we are comparing this against a similar struct in another TU,
1104      and did not assume they were compatible, we end up with an infinite
1105      loop.  */
1106   tu->val = 1;
1107   return tu;
1108 }
1109
1110 /* Free the seen types until we get to TU_TIL. */
1111
1112 static void
1113 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1114 {
1115   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1116   while (tu != tu_til)
1117     {
1118       const struct tagged_tu_seen_cache *const tu1
1119         = (const struct tagged_tu_seen_cache *) tu;
1120       tu = tu1->next;
1121       free (CONST_CAST (struct tagged_tu_seen_cache *, tu1));
1122     }
1123   tagged_tu_seen_base = tu_til;
1124 }
1125
1126 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1127    compatible.  If the two types are not the same (which has been
1128    checked earlier), this can only happen when multiple translation
1129    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1130    rules.  */
1131
1132 static int
1133 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1134 {
1135   tree s1, s2;
1136   bool needs_warning = false;
1137
1138   /* We have to verify that the tags of the types are the same.  This
1139      is harder than it looks because this may be a typedef, so we have
1140      to go look at the original type.  It may even be a typedef of a
1141      typedef...
1142      In the case of compiler-created builtin structs the TYPE_DECL
1143      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1144   while (TYPE_NAME (t1)
1145          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1146          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1147     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1148
1149   while (TYPE_NAME (t2)
1150          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1151          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1152     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1153
1154   /* C90 didn't have the requirement that the two tags be the same.  */
1155   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1156     return 0;
1157
1158   /* C90 didn't say what happened if one or both of the types were
1159      incomplete; we choose to follow C99 rules here, which is that they
1160      are compatible.  */
1161   if (TYPE_SIZE (t1) == NULL
1162       || TYPE_SIZE (t2) == NULL)
1163     return 1;
1164
1165   {
1166     const struct tagged_tu_seen_cache * tts_i;
1167     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1168       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1169         return tts_i->val;
1170   }
1171
1172   switch (TREE_CODE (t1))
1173     {
1174     case ENUMERAL_TYPE:
1175       {
1176         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1177         /* Speed up the case where the type values are in the same order.  */
1178         tree tv1 = TYPE_VALUES (t1);
1179         tree tv2 = TYPE_VALUES (t2);
1180
1181         if (tv1 == tv2)
1182           {
1183             return 1;
1184           }
1185
1186         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1187           {
1188             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1189               break;
1190             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1191               {
1192                 tu->val = 0;
1193                 return 0;
1194               }
1195           }
1196
1197         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1198           {
1199             return 1;
1200           }
1201         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1202           {
1203             tu->val = 0;
1204             return 0;
1205           }
1206
1207         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1208           {
1209             tu->val = 0;
1210             return 0;
1211           }
1212
1213         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1214           {
1215             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1216             if (s2 == NULL
1217                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1218               {
1219                 tu->val = 0;
1220                 return 0;
1221               }
1222           }
1223         return 1;
1224       }
1225
1226     case UNION_TYPE:
1227       {
1228         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1229         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1230           {
1231             tu->val = 0;
1232             return 0;
1233           }
1234
1235         /*  Speed up the common case where the fields are in the same order. */
1236         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1237              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1238           {
1239             int result;
1240
1241             if (DECL_NAME (s1) != DECL_NAME (s2))
1242               break;
1243             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1244
1245             if (result != 1 && !DECL_NAME (s1))
1246               break;
1247             if (result == 0)
1248               {
1249                 tu->val = 0;
1250                 return 0;
1251               }
1252             if (result == 2)
1253               needs_warning = true;
1254
1255             if (TREE_CODE (s1) == FIELD_DECL
1256                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1257                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1258               {
1259                 tu->val = 0;
1260                 return 0;
1261               }
1262           }
1263         if (!s1 && !s2)
1264           {
1265             tu->val = needs_warning ? 2 : 1;
1266             return tu->val;
1267           }
1268
1269         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1270           {
1271             bool ok = false;
1272
1273             for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1274               if (DECL_NAME (s1) == DECL_NAME (s2))
1275                 {
1276                   int result;
1277
1278                   result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1279
1280                   if (result != 1 && !DECL_NAME (s1))
1281                     continue;
1282                   if (result == 0)
1283                     {
1284                       tu->val = 0;
1285                       return 0;
1286                     }
1287                   if (result == 2)
1288                     needs_warning = true;
1289
1290                   if (TREE_CODE (s1) == FIELD_DECL
1291                       && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1292                                            DECL_FIELD_BIT_OFFSET (s2)) != 1)
1293                     break;
1294
1295                   ok = true;
1296                   break;
1297                 }
1298             if (!ok)
1299               {
1300                 tu->val = 0;
1301                 return 0;
1302               }
1303           }
1304         tu->val = needs_warning ? 2 : 10;
1305         return tu->val;
1306       }
1307
1308     case RECORD_TYPE:
1309       {
1310         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1311
1312         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1313              s1 && s2;
1314              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1315           {
1316             int result;
1317             if (TREE_CODE (s1) != TREE_CODE (s2)
1318                 || DECL_NAME (s1) != DECL_NAME (s2))
1319               break;
1320             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1321             if (result == 0)
1322               break;
1323             if (result == 2)
1324               needs_warning = true;
1325
1326             if (TREE_CODE (s1) == FIELD_DECL
1327                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1328                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1329               break;
1330           }
1331         if (s1 && s2)
1332           tu->val = 0;
1333         else
1334           tu->val = needs_warning ? 2 : 1;
1335         return tu->val;
1336       }
1337
1338     default:
1339       gcc_unreachable ();
1340     }
1341 }
1342
1343 /* Return 1 if two function types F1 and F2 are compatible.
1344    If either type specifies no argument types,
1345    the other must specify a fixed number of self-promoting arg types.
1346    Otherwise, if one type specifies only the number of arguments,
1347    the other must specify that number of self-promoting arg types.
1348    Otherwise, the argument types must match.  */
1349
1350 static int
1351 function_types_compatible_p (const_tree f1, const_tree f2)
1352 {
1353   tree args1, args2;
1354   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1355   int val = 1;
1356   int val1;
1357   tree ret1, ret2;
1358
1359   ret1 = TREE_TYPE (f1);
1360   ret2 = TREE_TYPE (f2);
1361
1362   /* 'volatile' qualifiers on a function's return type used to mean
1363      the function is noreturn.  */
1364   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1365     pedwarn (input_location, 0, "function return types not compatible due to %<volatile%>");
1366   if (TYPE_VOLATILE (ret1))
1367     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1368                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1369   if (TYPE_VOLATILE (ret2))
1370     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1371                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1372   val = comptypes_internal (ret1, ret2);
1373   if (val == 0)
1374     return 0;
1375
1376   args1 = TYPE_ARG_TYPES (f1);
1377   args2 = TYPE_ARG_TYPES (f2);
1378
1379   /* An unspecified parmlist matches any specified parmlist
1380      whose argument types don't need default promotions.  */
1381
1382   if (args1 == 0)
1383     {
1384       if (!self_promoting_args_p (args2))
1385         return 0;
1386       /* If one of these types comes from a non-prototype fn definition,
1387          compare that with the other type's arglist.
1388          If they don't match, ask for a warning (but no error).  */
1389       if (TYPE_ACTUAL_ARG_TYPES (f1)
1390           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1391         val = 2;
1392       return val;
1393     }
1394   if (args2 == 0)
1395     {
1396       if (!self_promoting_args_p (args1))
1397         return 0;
1398       if (TYPE_ACTUAL_ARG_TYPES (f2)
1399           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1400         val = 2;
1401       return val;
1402     }
1403
1404   /* Both types have argument lists: compare them and propagate results.  */
1405   val1 = type_lists_compatible_p (args1, args2);
1406   return val1 != 1 ? val1 : val;
1407 }
1408
1409 /* Check two lists of types for compatibility,
1410    returning 0 for incompatible, 1 for compatible,
1411    or 2 for compatible with warning.  */
1412
1413 static int
1414 type_lists_compatible_p (const_tree args1, const_tree args2)
1415 {
1416   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1417   int val = 1;
1418   int newval = 0;
1419
1420   while (1)
1421     {
1422       tree a1, mv1, a2, mv2;
1423       if (args1 == 0 && args2 == 0)
1424         return val;
1425       /* If one list is shorter than the other,
1426          they fail to match.  */
1427       if (args1 == 0 || args2 == 0)
1428         return 0;
1429       mv1 = a1 = TREE_VALUE (args1);
1430       mv2 = a2 = TREE_VALUE (args2);
1431       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1432         mv1 = TYPE_MAIN_VARIANT (mv1);
1433       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1434         mv2 = TYPE_MAIN_VARIANT (mv2);
1435       /* A null pointer instead of a type
1436          means there is supposed to be an argument
1437          but nothing is specified about what type it has.
1438          So match anything that self-promotes.  */
1439       if (a1 == 0)
1440         {
1441           if (c_type_promotes_to (a2) != a2)
1442             return 0;
1443         }
1444       else if (a2 == 0)
1445         {
1446           if (c_type_promotes_to (a1) != a1)
1447             return 0;
1448         }
1449       /* If one of the lists has an error marker, ignore this arg.  */
1450       else if (TREE_CODE (a1) == ERROR_MARK
1451                || TREE_CODE (a2) == ERROR_MARK)
1452         ;
1453       else if (!(newval = comptypes_internal (mv1, mv2)))
1454         {
1455           /* Allow  wait (union {union wait *u; int *i} *)
1456              and  wait (union wait *)  to be compatible.  */
1457           if (TREE_CODE (a1) == UNION_TYPE
1458               && (TYPE_NAME (a1) == 0
1459                   || TYPE_TRANSPARENT_UNION (a1))
1460               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1461               && tree_int_cst_equal (TYPE_SIZE (a1),
1462                                      TYPE_SIZE (a2)))
1463             {
1464               tree memb;
1465               for (memb = TYPE_FIELDS (a1);
1466                    memb; memb = TREE_CHAIN (memb))
1467                 {
1468                   tree mv3 = TREE_TYPE (memb);
1469                   if (mv3 && mv3 != error_mark_node
1470                       && TREE_CODE (mv3) != ARRAY_TYPE)
1471                     mv3 = TYPE_MAIN_VARIANT (mv3);
1472                   if (comptypes_internal (mv3, mv2))
1473                     break;
1474                 }
1475               if (memb == 0)
1476                 return 0;
1477             }
1478           else if (TREE_CODE (a2) == UNION_TYPE
1479                    && (TYPE_NAME (a2) == 0
1480                        || TYPE_TRANSPARENT_UNION (a2))
1481                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1482                    && tree_int_cst_equal (TYPE_SIZE (a2),
1483                                           TYPE_SIZE (a1)))
1484             {
1485               tree memb;
1486               for (memb = TYPE_FIELDS (a2);
1487                    memb; memb = TREE_CHAIN (memb))
1488                 {
1489                   tree mv3 = TREE_TYPE (memb);
1490                   if (mv3 && mv3 != error_mark_node
1491                       && TREE_CODE (mv3) != ARRAY_TYPE)
1492                     mv3 = TYPE_MAIN_VARIANT (mv3);
1493                   if (comptypes_internal (mv3, mv1))
1494                     break;
1495                 }
1496               if (memb == 0)
1497                 return 0;
1498             }
1499           else
1500             return 0;
1501         }
1502
1503       /* comptypes said ok, but record if it said to warn.  */
1504       if (newval > val)
1505         val = newval;
1506
1507       args1 = TREE_CHAIN (args1);
1508       args2 = TREE_CHAIN (args2);
1509     }
1510 }
1511 \f
1512 /* Compute the size to increment a pointer by.  */
1513
1514 static tree
1515 c_size_in_bytes (const_tree type)
1516 {
1517   enum tree_code code = TREE_CODE (type);
1518
1519   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1520     return size_one_node;
1521
1522   if (!COMPLETE_OR_VOID_TYPE_P (type))
1523     {
1524       error ("arithmetic on pointer to an incomplete type");
1525       return size_one_node;
1526     }
1527
1528   /* Convert in case a char is more than one unit.  */
1529   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1530                      size_int (TYPE_PRECISION (char_type_node)
1531                                / BITS_PER_UNIT));
1532 }
1533 \f
1534 /* Return either DECL or its known constant value (if it has one).  */
1535
1536 tree
1537 decl_constant_value (tree decl)
1538 {
1539   if (/* Don't change a variable array bound or initial value to a constant
1540          in a place where a variable is invalid.  Note that DECL_INITIAL
1541          isn't valid for a PARM_DECL.  */
1542       current_function_decl != 0
1543       && TREE_CODE (decl) != PARM_DECL
1544       && !TREE_THIS_VOLATILE (decl)
1545       && TREE_READONLY (decl)
1546       && DECL_INITIAL (decl) != 0
1547       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1548       /* This is invalid if initial value is not constant.
1549          If it has either a function call, a memory reference,
1550          or a variable, then re-evaluating it could give different results.  */
1551       && TREE_CONSTANT (DECL_INITIAL (decl))
1552       /* Check for cases where this is sub-optimal, even though valid.  */
1553       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1554     return DECL_INITIAL (decl);
1555   return decl;
1556 }
1557
1558 /* Return either DECL or its known constant value (if it has one), but
1559    return DECL if pedantic or DECL has mode BLKmode.  This is for
1560    bug-compatibility with the old behavior of decl_constant_value
1561    (before GCC 3.0); every use of this function is a bug and it should
1562    be removed before GCC 3.1.  It is not appropriate to use pedantic
1563    in a way that affects optimization, and BLKmode is probably not the
1564    right test for avoiding misoptimizations either.  */
1565
1566 static tree
1567 decl_constant_value_for_broken_optimization (tree decl)
1568 {
1569   tree ret;
1570
1571   if (pedantic || DECL_MODE (decl) == BLKmode)
1572     return decl;
1573
1574   ret = decl_constant_value (decl);
1575   /* Avoid unwanted tree sharing between the initializer and current
1576      function's body where the tree can be modified e.g. by the
1577      gimplifier.  */
1578   if (ret != decl && TREE_STATIC (decl))
1579     ret = unshare_expr (ret);
1580   return ret;
1581 }
1582
1583 /* Convert the array expression EXP to a pointer.  */
1584 static tree
1585 array_to_pointer_conversion (tree exp)
1586 {
1587   tree orig_exp = exp;
1588   tree type = TREE_TYPE (exp);
1589   tree adr;
1590   tree restype = TREE_TYPE (type);
1591   tree ptrtype;
1592
1593   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1594
1595   STRIP_TYPE_NOPS (exp);
1596
1597   if (TREE_NO_WARNING (orig_exp))
1598     TREE_NO_WARNING (exp) = 1;
1599
1600   ptrtype = build_pointer_type (restype);
1601
1602   if (TREE_CODE (exp) == INDIRECT_REF)
1603     return convert (ptrtype, TREE_OPERAND (exp, 0));
1604
1605   if (TREE_CODE (exp) == VAR_DECL)
1606     {
1607       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1608          ADDR_EXPR because it's the best way of representing what
1609          happens in C when we take the address of an array and place
1610          it in a pointer to the element type.  */
1611       adr = build1 (ADDR_EXPR, ptrtype, exp);
1612       if (!c_mark_addressable (exp))
1613         return error_mark_node;
1614       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1615       return adr;
1616     }
1617
1618   /* This way is better for a COMPONENT_REF since it can
1619      simplify the offset for a component.  */
1620   adr = build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 1);
1621   return convert (ptrtype, adr);
1622 }
1623
1624 /* Convert the function expression EXP to a pointer.  */
1625 static tree
1626 function_to_pointer_conversion (tree exp)
1627 {
1628   tree orig_exp = exp;
1629
1630   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1631
1632   STRIP_TYPE_NOPS (exp);
1633
1634   if (TREE_NO_WARNING (orig_exp))
1635     TREE_NO_WARNING (exp) = 1;
1636
1637   return build_unary_op (EXPR_LOCATION (exp), ADDR_EXPR, exp, 0);
1638 }
1639
1640 /* Perform the default conversion of arrays and functions to pointers.
1641    Return the result of converting EXP.  For any other expression, just
1642    return EXP after removing NOPs.  */
1643
1644 struct c_expr
1645 default_function_array_conversion (struct c_expr exp)
1646 {
1647   tree orig_exp = exp.value;
1648   tree type = TREE_TYPE (exp.value);
1649   enum tree_code code = TREE_CODE (type);
1650
1651   switch (code)
1652     {
1653     case ARRAY_TYPE:
1654       {
1655         bool not_lvalue = false;
1656         bool lvalue_array_p;
1657
1658         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1659                 || CONVERT_EXPR_P (exp.value))
1660                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1661           {
1662             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1663               not_lvalue = true;
1664             exp.value = TREE_OPERAND (exp.value, 0);
1665           }
1666
1667         if (TREE_NO_WARNING (orig_exp))
1668           TREE_NO_WARNING (exp.value) = 1;
1669
1670         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1671         if (!flag_isoc99 && !lvalue_array_p)
1672           {
1673             /* Before C99, non-lvalue arrays do not decay to pointers.
1674                Normally, using such an array would be invalid; but it can
1675                be used correctly inside sizeof or as a statement expression.
1676                Thus, do not give an error here; an error will result later.  */
1677             return exp;
1678           }
1679
1680         exp.value = array_to_pointer_conversion (exp.value);
1681       }
1682       break;
1683     case FUNCTION_TYPE:
1684       exp.value = function_to_pointer_conversion (exp.value);
1685       break;
1686     default:
1687       STRIP_TYPE_NOPS (exp.value);
1688       if (TREE_NO_WARNING (orig_exp))
1689         TREE_NO_WARNING (exp.value) = 1;
1690       break;
1691     }
1692
1693   return exp;
1694 }
1695
1696
1697 /* EXP is an expression of integer type.  Apply the integer promotions
1698    to it and return the promoted value.  */
1699
1700 tree
1701 perform_integral_promotions (tree exp)
1702 {
1703   tree type = TREE_TYPE (exp);
1704   enum tree_code code = TREE_CODE (type);
1705
1706   gcc_assert (INTEGRAL_TYPE_P (type));
1707
1708   /* Normally convert enums to int,
1709      but convert wide enums to something wider.  */
1710   if (code == ENUMERAL_TYPE)
1711     {
1712       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1713                                           TYPE_PRECISION (integer_type_node)),
1714                                      ((TYPE_PRECISION (type)
1715                                        >= TYPE_PRECISION (integer_type_node))
1716                                       && TYPE_UNSIGNED (type)));
1717
1718       return convert (type, exp);
1719     }
1720
1721   /* ??? This should no longer be needed now bit-fields have their
1722      proper types.  */
1723   if (TREE_CODE (exp) == COMPONENT_REF
1724       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1725       /* If it's thinner than an int, promote it like a
1726          c_promoting_integer_type_p, otherwise leave it alone.  */
1727       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1728                                TYPE_PRECISION (integer_type_node)))
1729     return convert (integer_type_node, exp);
1730
1731   if (c_promoting_integer_type_p (type))
1732     {
1733       /* Preserve unsignedness if not really getting any wider.  */
1734       if (TYPE_UNSIGNED (type)
1735           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1736         return convert (unsigned_type_node, exp);
1737
1738       return convert (integer_type_node, exp);
1739     }
1740
1741   return exp;
1742 }
1743
1744
1745 /* Perform default promotions for C data used in expressions.
1746    Enumeral types or short or char are converted to int.
1747    In addition, manifest constants symbols are replaced by their values.  */
1748
1749 tree
1750 default_conversion (tree exp)
1751 {
1752   tree orig_exp;
1753   tree type = TREE_TYPE (exp);
1754   enum tree_code code = TREE_CODE (type);
1755
1756   /* Functions and arrays have been converted during parsing.  */
1757   gcc_assert (code != FUNCTION_TYPE);
1758   if (code == ARRAY_TYPE)
1759     return exp;
1760
1761   /* Constants can be used directly unless they're not loadable.  */
1762   if (TREE_CODE (exp) == CONST_DECL)
1763     exp = DECL_INITIAL (exp);
1764
1765   /* Replace a nonvolatile const static variable with its value unless
1766      it is an array, in which case we must be sure that taking the
1767      address of the array produces consistent results.  */
1768   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1769     {
1770       exp = decl_constant_value_for_broken_optimization (exp);
1771       type = TREE_TYPE (exp);
1772     }
1773
1774   /* Strip no-op conversions.  */
1775   orig_exp = exp;
1776   STRIP_TYPE_NOPS (exp);
1777
1778   if (TREE_NO_WARNING (orig_exp))
1779     TREE_NO_WARNING (exp) = 1;
1780
1781   if (code == VOID_TYPE)
1782     {
1783       error ("void value not ignored as it ought to be");
1784       return error_mark_node;
1785     }
1786
1787   exp = require_complete_type (exp);
1788   if (exp == error_mark_node)
1789     return error_mark_node;
1790
1791   if (INTEGRAL_TYPE_P (type))
1792     return perform_integral_promotions (exp);
1793
1794   return exp;
1795 }
1796 \f
1797 /* Look up COMPONENT in a structure or union DECL.
1798
1799    If the component name is not found, returns NULL_TREE.  Otherwise,
1800    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1801    stepping down the chain to the component, which is in the last
1802    TREE_VALUE of the list.  Normally the list is of length one, but if
1803    the component is embedded within (nested) anonymous structures or
1804    unions, the list steps down the chain to the component.  */
1805
1806 static tree
1807 lookup_field (tree decl, tree component)
1808 {
1809   tree type = TREE_TYPE (decl);
1810   tree field;
1811
1812   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1813      to the field elements.  Use a binary search on this array to quickly
1814      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1815      will always be set for structures which have many elements.  */
1816
1817   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1818     {
1819       int bot, top, half;
1820       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1821
1822       field = TYPE_FIELDS (type);
1823       bot = 0;
1824       top = TYPE_LANG_SPECIFIC (type)->s->len;
1825       while (top - bot > 1)
1826         {
1827           half = (top - bot + 1) >> 1;
1828           field = field_array[bot+half];
1829
1830           if (DECL_NAME (field) == NULL_TREE)
1831             {
1832               /* Step through all anon unions in linear fashion.  */
1833               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1834                 {
1835                   field = field_array[bot++];
1836                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1837                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1838                     {
1839                       tree anon = lookup_field (field, component);
1840
1841                       if (anon)
1842                         return tree_cons (NULL_TREE, field, anon);
1843                     }
1844                 }
1845
1846               /* Entire record is only anon unions.  */
1847               if (bot > top)
1848                 return NULL_TREE;
1849
1850               /* Restart the binary search, with new lower bound.  */
1851               continue;
1852             }
1853
1854           if (DECL_NAME (field) == component)
1855             break;
1856           if (DECL_NAME (field) < component)
1857             bot += half;
1858           else
1859             top = bot + half;
1860         }
1861
1862       if (DECL_NAME (field_array[bot]) == component)
1863         field = field_array[bot];
1864       else if (DECL_NAME (field) != component)
1865         return NULL_TREE;
1866     }
1867   else
1868     {
1869       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1870         {
1871           if (DECL_NAME (field) == NULL_TREE
1872               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1873                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1874             {
1875               tree anon = lookup_field (field, component);
1876
1877               if (anon)
1878                 return tree_cons (NULL_TREE, field, anon);
1879             }
1880
1881           if (DECL_NAME (field) == component)
1882             break;
1883         }
1884
1885       if (field == NULL_TREE)
1886         return NULL_TREE;
1887     }
1888
1889   return tree_cons (NULL_TREE, field, NULL_TREE);
1890 }
1891
1892 /* Make an expression to refer to the COMPONENT field of
1893    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1894
1895 tree
1896 build_component_ref (tree datum, tree component)
1897 {
1898   tree type = TREE_TYPE (datum);
1899   enum tree_code code = TREE_CODE (type);
1900   tree field = NULL;
1901   tree ref;
1902
1903   if (!objc_is_public (datum, component))
1904     return error_mark_node;
1905
1906   /* See if there is a field or component with name COMPONENT.  */
1907
1908   if (code == RECORD_TYPE || code == UNION_TYPE)
1909     {
1910       if (!COMPLETE_TYPE_P (type))
1911         {
1912           c_incomplete_type_error (NULL_TREE, type);
1913           return error_mark_node;
1914         }
1915
1916       field = lookup_field (datum, component);
1917
1918       if (!field)
1919         {
1920           error ("%qT has no member named %qE", type, component);
1921           return error_mark_node;
1922         }
1923
1924       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1925          This might be better solved in future the way the C++ front
1926          end does it - by giving the anonymous entities each a
1927          separate name and type, and then have build_component_ref
1928          recursively call itself.  We can't do that here.  */
1929       do
1930         {
1931           tree subdatum = TREE_VALUE (field);
1932           int quals;
1933           tree subtype;
1934
1935           if (TREE_TYPE (subdatum) == error_mark_node)
1936             return error_mark_node;
1937
1938           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1939           quals |= TYPE_QUALS (TREE_TYPE (datum));
1940           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1941
1942           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1943                         NULL_TREE);
1944           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1945             TREE_READONLY (ref) = 1;
1946           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1947             TREE_THIS_VOLATILE (ref) = 1;
1948
1949           if (TREE_DEPRECATED (subdatum))
1950             warn_deprecated_use (subdatum);
1951
1952           datum = ref;
1953
1954           field = TREE_CHAIN (field);
1955         }
1956       while (field);
1957
1958       return ref;
1959     }
1960   else if (code != ERROR_MARK)
1961     error ("request for member %qE in something not a structure or union",
1962            component);
1963
1964   return error_mark_node;
1965 }
1966 \f
1967 /* Given an expression PTR for a pointer, return an expression
1968    for the value pointed to.
1969    ERRORSTRING is the name of the operator to appear in error messages.
1970
1971    LOC is the location to use for the generated tree.  */
1972
1973 tree
1974 build_indirect_ref (location_t loc, tree ptr, const char *errorstring)
1975 {
1976   tree pointer = default_conversion (ptr);
1977   tree type = TREE_TYPE (pointer);
1978   tree ref;
1979
1980   if (TREE_CODE (type) == POINTER_TYPE)
1981     {
1982       if (CONVERT_EXPR_P (pointer)
1983           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1984         {
1985           /* If a warning is issued, mark it to avoid duplicates from
1986              the backend.  This only needs to be done at
1987              warn_strict_aliasing > 2.  */
1988           if (warn_strict_aliasing > 2)
1989             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1990                                          type, TREE_OPERAND (pointer, 0)))
1991               TREE_NO_WARNING (pointer) = 1;
1992         }
1993
1994       if (TREE_CODE (pointer) == ADDR_EXPR
1995           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1996               == TREE_TYPE (type)))
1997         {
1998           ref = TREE_OPERAND (pointer, 0);
1999           protected_set_expr_location (ref, loc);
2000           return ref;
2001         }
2002       else
2003         {
2004           tree t = TREE_TYPE (type);
2005
2006           ref = build1 (INDIRECT_REF, t, pointer);
2007
2008           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
2009             {
2010               error_at (loc, "dereferencing pointer to incomplete type");
2011               return error_mark_node;
2012             }
2013           if (VOID_TYPE_P (t) && skip_evaluation == 0)
2014             warning_at (loc, 0, "dereferencing %<void *%> pointer");
2015
2016           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2017              so that we get the proper error message if the result is used
2018              to assign to.  Also, &* is supposed to be a no-op.
2019              And ANSI C seems to specify that the type of the result
2020              should be the const type.  */
2021           /* A de-reference of a pointer to const is not a const.  It is valid
2022              to change it via some other pointer.  */
2023           TREE_READONLY (ref) = TYPE_READONLY (t);
2024           TREE_SIDE_EFFECTS (ref)
2025             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2026           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2027           protected_set_expr_location (ref, loc);
2028           return ref;
2029         }
2030     }
2031   else if (TREE_CODE (pointer) != ERROR_MARK)
2032     error_at (loc,
2033               "invalid type argument of %qs (have %qT)", errorstring, type);
2034   return error_mark_node;
2035 }
2036
2037 /* This handles expressions of the form "a[i]", which denotes
2038    an array reference.
2039
2040    This is logically equivalent in C to *(a+i), but we may do it differently.
2041    If A is a variable or a member, we generate a primitive ARRAY_REF.
2042    This avoids forcing the array out of registers, and can work on
2043    arrays that are not lvalues (for example, members of structures returned
2044    by functions).
2045
2046    LOC is the location to use for the returned expression.  */
2047
2048 tree
2049 build_array_ref (tree array, tree index, location_t loc)
2050 {
2051   tree ret;
2052   bool swapped = false;
2053   if (TREE_TYPE (array) == error_mark_node
2054       || TREE_TYPE (index) == error_mark_node)
2055     return error_mark_node;
2056
2057   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2058       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2059     {
2060       tree temp;
2061       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2062           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2063         {
2064           error_at (loc, "subscripted value is neither array nor pointer");
2065           return error_mark_node;
2066         }
2067       temp = array;
2068       array = index;
2069       index = temp;
2070       swapped = true;
2071     }
2072
2073   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2074     {
2075       error_at (loc, "array subscript is not an integer");
2076       return error_mark_node;
2077     }
2078
2079   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2080     {
2081       error_at (loc, "subscripted value is pointer to function");
2082       return error_mark_node;
2083     }
2084
2085   /* ??? Existing practice has been to warn only when the char
2086      index is syntactically the index, not for char[array].  */
2087   if (!swapped)
2088      warn_array_subscript_with_type_char (index);
2089
2090   /* Apply default promotions *after* noticing character types.  */
2091   index = default_conversion (index);
2092
2093   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2094
2095   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2096     {
2097       tree rval, type;
2098
2099       /* An array that is indexed by a non-constant
2100          cannot be stored in a register; we must be able to do
2101          address arithmetic on its address.
2102          Likewise an array of elements of variable size.  */
2103       if (TREE_CODE (index) != INTEGER_CST
2104           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2105               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2106         {
2107           if (!c_mark_addressable (array))
2108             return error_mark_node;
2109         }
2110       /* An array that is indexed by a constant value which is not within
2111          the array bounds cannot be stored in a register either; because we
2112          would get a crash in store_bit_field/extract_bit_field when trying
2113          to access a non-existent part of the register.  */
2114       if (TREE_CODE (index) == INTEGER_CST
2115           && TYPE_DOMAIN (TREE_TYPE (array))
2116           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2117         {
2118           if (!c_mark_addressable (array))
2119             return error_mark_node;
2120         }
2121
2122       if (pedantic)
2123         {
2124           tree foo = array;
2125           while (TREE_CODE (foo) == COMPONENT_REF)
2126             foo = TREE_OPERAND (foo, 0);
2127           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2128             pedwarn (loc, OPT_pedantic,
2129                      "ISO C forbids subscripting %<register%> array");
2130           else if (!flag_isoc99 && !lvalue_p (foo))
2131             pedwarn (loc, OPT_pedantic,
2132                      "ISO C90 forbids subscripting non-lvalue array");
2133         }
2134
2135       type = TREE_TYPE (TREE_TYPE (array));
2136       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2137       /* Array ref is const/volatile if the array elements are
2138          or if the array is.  */
2139       TREE_READONLY (rval)
2140         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2141             | TREE_READONLY (array));
2142       TREE_SIDE_EFFECTS (rval)
2143         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2144             | TREE_SIDE_EFFECTS (array));
2145       TREE_THIS_VOLATILE (rval)
2146         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2147             /* This was added by rms on 16 Nov 91.
2148                It fixes  vol struct foo *a;  a->elts[1]
2149                in an inline function.
2150                Hope it doesn't break something else.  */
2151             | TREE_THIS_VOLATILE (array));
2152       ret = require_complete_type (fold (rval));
2153       protected_set_expr_location (ret, loc);
2154       return ret;
2155     }
2156   else
2157     {
2158       tree ar = default_conversion (array);
2159
2160       if (ar == error_mark_node)
2161         return ar;
2162
2163       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2164       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2165
2166       return build_indirect_ref
2167         (loc, build_binary_op (loc, PLUS_EXPR, ar, index, 0),
2168          "array indexing");
2169     }
2170 }
2171 \f
2172 /* Build an external reference to identifier ID.  FUN indicates
2173    whether this will be used for a function call.  LOC is the source
2174    location of the identifier.  */
2175 tree
2176 build_external_ref (tree id, int fun, location_t loc)
2177 {
2178   tree ref;
2179   tree decl = lookup_name (id);
2180
2181   /* In Objective-C, an instance variable (ivar) may be preferred to
2182      whatever lookup_name() found.  */
2183   decl = objc_lookup_ivar (decl, id);
2184
2185   if (decl && decl != error_mark_node)
2186     ref = decl;
2187   else if (fun)
2188     /* Implicit function declaration.  */
2189     ref = implicitly_declare (id);
2190   else if (decl == error_mark_node)
2191     /* Don't complain about something that's already been
2192        complained about.  */
2193     return error_mark_node;
2194   else
2195     {
2196       undeclared_variable (id, loc);
2197       return error_mark_node;
2198     }
2199
2200   if (TREE_TYPE (ref) == error_mark_node)
2201     return error_mark_node;
2202
2203   if (TREE_DEPRECATED (ref))
2204     warn_deprecated_use (ref);
2205
2206   /* Recursive call does not count as usage.  */
2207   if (ref != current_function_decl)
2208     {
2209       TREE_USED (ref) = 1;
2210     }
2211
2212   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2213     {
2214       if (!in_sizeof && !in_typeof)
2215         C_DECL_USED (ref) = 1;
2216       else if (DECL_INITIAL (ref) == 0
2217                && DECL_EXTERNAL (ref)
2218                && !TREE_PUBLIC (ref))
2219         record_maybe_used_decl (ref);
2220     }
2221
2222   if (TREE_CODE (ref) == CONST_DECL)
2223     {
2224       used_types_insert (TREE_TYPE (ref));
2225       ref = DECL_INITIAL (ref);
2226       TREE_CONSTANT (ref) = 1;
2227     }
2228   else if (current_function_decl != 0
2229            && !DECL_FILE_SCOPE_P (current_function_decl)
2230            && (TREE_CODE (ref) == VAR_DECL
2231                || TREE_CODE (ref) == PARM_DECL
2232                || TREE_CODE (ref) == FUNCTION_DECL))
2233     {
2234       tree context = decl_function_context (ref);
2235
2236       if (context != 0 && context != current_function_decl)
2237         DECL_NONLOCAL (ref) = 1;
2238     }
2239   /* C99 6.7.4p3: An inline definition of a function with external
2240      linkage ... shall not contain a reference to an identifier with
2241      internal linkage.  */
2242   else if (current_function_decl != 0
2243            && DECL_DECLARED_INLINE_P (current_function_decl)
2244            && DECL_EXTERNAL (current_function_decl)
2245            && VAR_OR_FUNCTION_DECL_P (ref)
2246            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2247            && ! TREE_PUBLIC (ref)
2248            && DECL_CONTEXT (ref) != current_function_decl)
2249     pedwarn (loc, 0, "%qD is static but used in inline function %qD "
2250              "which is not static", ref, current_function_decl);
2251
2252   return ref;
2253 }
2254
2255 /* Record details of decls possibly used inside sizeof or typeof.  */
2256 struct maybe_used_decl
2257 {
2258   /* The decl.  */
2259   tree decl;
2260   /* The level seen at (in_sizeof + in_typeof).  */
2261   int level;
2262   /* The next one at this level or above, or NULL.  */
2263   struct maybe_used_decl *next;
2264 };
2265
2266 static struct maybe_used_decl *maybe_used_decls;
2267
2268 /* Record that DECL, an undefined static function reference seen
2269    inside sizeof or typeof, might be used if the operand of sizeof is
2270    a VLA type or the operand of typeof is a variably modified
2271    type.  */
2272
2273 static void
2274 record_maybe_used_decl (tree decl)
2275 {
2276   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2277   t->decl = decl;
2278   t->level = in_sizeof + in_typeof;
2279   t->next = maybe_used_decls;
2280   maybe_used_decls = t;
2281 }
2282
2283 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2284    USED is false, just discard them.  If it is true, mark them used
2285    (if no longer inside sizeof or typeof) or move them to the next
2286    level up (if still inside sizeof or typeof).  */
2287
2288 void
2289 pop_maybe_used (bool used)
2290 {
2291   struct maybe_used_decl *p = maybe_used_decls;
2292   int cur_level = in_sizeof + in_typeof;
2293   while (p && p->level > cur_level)
2294     {
2295       if (used)
2296         {
2297           if (cur_level == 0)
2298             C_DECL_USED (p->decl) = 1;
2299           else
2300             p->level = cur_level;
2301         }
2302       p = p->next;
2303     }
2304   if (!used || cur_level == 0)
2305     maybe_used_decls = p;
2306 }
2307
2308 /* Return the result of sizeof applied to EXPR.  */
2309
2310 struct c_expr
2311 c_expr_sizeof_expr (struct c_expr expr)
2312 {
2313   struct c_expr ret;
2314   if (expr.value == error_mark_node)
2315     {
2316       ret.value = error_mark_node;
2317       ret.original_code = ERROR_MARK;
2318       pop_maybe_used (false);
2319     }
2320   else
2321     {
2322       ret.value = c_sizeof (TREE_TYPE (expr.value));
2323       ret.original_code = ERROR_MARK;
2324       if (c_vla_type_p (TREE_TYPE (expr.value)))
2325         {
2326           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2327           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2328         }
2329       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2330     }
2331   return ret;
2332 }
2333
2334 /* Return the result of sizeof applied to T, a structure for the type
2335    name passed to sizeof (rather than the type itself).  */
2336
2337 struct c_expr
2338 c_expr_sizeof_type (struct c_type_name *t)
2339 {
2340   tree type;
2341   struct c_expr ret;
2342   type = groktypename (t);
2343   ret.value = c_sizeof (type);
2344   ret.original_code = ERROR_MARK;
2345   pop_maybe_used (type != error_mark_node
2346                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2347   return ret;
2348 }
2349
2350 /* Build a function call to function FUNCTION with parameters PARAMS.
2351    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2352    TREE_VALUE of each node is a parameter-expression.
2353    FUNCTION's data type may be a function type or a pointer-to-function.  */
2354
2355 tree
2356 build_function_call (tree function, tree params)
2357 {
2358   tree fntype, fundecl = 0;
2359   tree name = NULL_TREE, result;
2360   tree tem;
2361   int nargs;
2362   tree *argarray;
2363
2364
2365   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2366   STRIP_TYPE_NOPS (function);
2367
2368   /* Convert anything with function type to a pointer-to-function.  */
2369   if (TREE_CODE (function) == FUNCTION_DECL)
2370     {
2371       /* Implement type-directed function overloading for builtins.
2372          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2373          handle all the type checking.  The result is a complete expression
2374          that implements this function call.  */
2375       tem = resolve_overloaded_builtin (function, params);
2376       if (tem)
2377         return tem;
2378
2379       name = DECL_NAME (function);
2380       fundecl = function;
2381     }
2382   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2383     function = function_to_pointer_conversion (function);
2384
2385   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2386      expressions, like those used for ObjC messenger dispatches.  */
2387   function = objc_rewrite_function_call (function, params);
2388
2389   fntype = TREE_TYPE (function);
2390
2391   if (TREE_CODE (fntype) == ERROR_MARK)
2392     return error_mark_node;
2393
2394   if (!(TREE_CODE (fntype) == POINTER_TYPE
2395         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2396     {
2397       error ("called object %qE is not a function", function);
2398       return error_mark_node;
2399     }
2400
2401   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2402     current_function_returns_abnormally = 1;
2403
2404   /* fntype now gets the type of function pointed to.  */
2405   fntype = TREE_TYPE (fntype);
2406
2407   /* Check that the function is called through a compatible prototype.
2408      If it is not, replace the call by a trap, wrapped up in a compound
2409      expression if necessary.  This has the nice side-effect to prevent
2410      the tree-inliner from generating invalid assignment trees which may
2411      blow up in the RTL expander later.  */
2412   if (CONVERT_EXPR_P (function)
2413       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2414       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2415       && !comptypes (fntype, TREE_TYPE (tem)))
2416     {
2417       tree return_type = TREE_TYPE (fntype);
2418       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2419                                        NULL_TREE);
2420
2421       /* This situation leads to run-time undefined behavior.  We can't,
2422          therefore, simply error unless we can prove that all possible
2423          executions of the program must execute the code.  */
2424       if (warning (0, "function called through a non-compatible type"))
2425         /* We can, however, treat "undefined" any way we please.
2426            Call abort to encourage the user to fix the program.  */
2427         inform (input_location, "if this code is reached, the program will abort");
2428
2429       if (VOID_TYPE_P (return_type))
2430         return trap;
2431       else
2432         {
2433           tree rhs;
2434
2435           if (AGGREGATE_TYPE_P (return_type))
2436             rhs = build_compound_literal (return_type,
2437                                           build_constructor (return_type, 0));
2438           else
2439             rhs = fold_convert (return_type, integer_zero_node);
2440
2441           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2442         }
2443     }
2444
2445   /* Convert the parameters to the types declared in the
2446      function prototype, or apply default promotions.  */
2447
2448   nargs = list_length (params);
2449   argarray = (tree *) alloca (nargs * sizeof (tree));
2450   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2451                              params, function, fundecl);
2452   if (nargs < 0)
2453     return error_mark_node;
2454
2455   /* Check that arguments to builtin functions match the expectations.  */
2456   if (fundecl
2457       && DECL_BUILT_IN (fundecl)
2458       && DECL_BUILT_IN_CLASS (fundecl) == BUILT_IN_NORMAL
2459       && !check_builtin_function_arguments (fundecl, nargs, argarray))
2460     return error_mark_node;
2461
2462   /* Check that the arguments to the function are valid.  */
2463   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2464                             TYPE_ARG_TYPES (fntype));
2465
2466   if (require_constant_value)
2467     {
2468       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2469                                                   function, nargs, argarray);
2470       if (TREE_CONSTANT (result)
2471           && (name == NULL_TREE
2472               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2473         pedwarn_init (input_location, 0, "initializer element is not constant");
2474     }
2475   else
2476     result = fold_build_call_array (TREE_TYPE (fntype),
2477                                     function, nargs, argarray);
2478
2479   if (VOID_TYPE_P (TREE_TYPE (result)))
2480     return result;
2481   return require_complete_type (result);
2482 }
2483 \f
2484 /* Convert the argument expressions in the list VALUES
2485    to the types in the list TYPELIST.  The resulting arguments are
2486    stored in the array ARGARRAY which has size NARGS.
2487
2488    If TYPELIST is exhausted, or when an element has NULL as its type,
2489    perform the default conversions.
2490
2491    PARMLIST is the chain of parm decls for the function being called.
2492    It may be 0, if that info is not available.
2493    It is used only for generating error messages.
2494
2495    FUNCTION is a tree for the called function.  It is used only for
2496    error messages, where it is formatted with %qE.
2497
2498    This is also where warnings about wrong number of args are generated.
2499
2500    VALUES is a chain of TREE_LIST nodes with the elements of the list
2501    in the TREE_VALUE slots of those nodes.
2502
2503    Returns the actual number of arguments processed (which may be less
2504    than NARGS in some error situations), or -1 on failure.  */
2505
2506 static int
2507 convert_arguments (int nargs, tree *argarray,
2508                    tree typelist, tree values, tree function, tree fundecl)
2509 {
2510   tree typetail, valtail;
2511   int parmnum;
2512   const bool type_generic = fundecl
2513     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2514   tree selector;
2515
2516   /* Change pointer to function to the function itself for
2517      diagnostics.  */
2518   if (TREE_CODE (function) == ADDR_EXPR
2519       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2520     function = TREE_OPERAND (function, 0);
2521
2522   /* Handle an ObjC selector specially for diagnostics.  */
2523   selector = objc_message_selector ();
2524
2525   /* Scan the given expressions and types, producing individual
2526      converted arguments and storing them in ARGARRAY.  */
2527
2528   for (valtail = values, typetail = typelist, parmnum = 0;
2529        valtail;
2530        valtail = TREE_CHAIN (valtail), parmnum++)
2531     {
2532       tree type = typetail ? TREE_VALUE (typetail) : 0;
2533       tree val = TREE_VALUE (valtail);
2534       tree rname = function;
2535       int argnum = parmnum + 1;
2536       const char *invalid_func_diag;
2537
2538       if (type == void_type_node)
2539         {
2540           error ("too many arguments to function %qE", function);
2541           return parmnum;
2542         }
2543
2544       if (selector && argnum > 2)
2545         {
2546           rname = selector;
2547           argnum -= 2;
2548         }
2549
2550       STRIP_TYPE_NOPS (val);
2551
2552       val = require_complete_type (val);
2553
2554       if (type != 0)
2555         {
2556           /* Formal parm type is specified by a function prototype.  */
2557           tree parmval;
2558
2559           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2560             {
2561               error ("type of formal parameter %d is incomplete", parmnum + 1);
2562               parmval = val;
2563             }
2564           else
2565             {
2566               /* Optionally warn about conversions that
2567                  differ from the default conversions.  */
2568               if (warn_traditional_conversion || warn_traditional)
2569                 {
2570                   unsigned int formal_prec = TYPE_PRECISION (type);
2571
2572                   if (INTEGRAL_TYPE_P (type)
2573                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2574                     warning (0, "passing argument %d of %qE as integer "
2575                              "rather than floating due to prototype",
2576                              argnum, rname);
2577                   if (INTEGRAL_TYPE_P (type)
2578                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2579                     warning (0, "passing argument %d of %qE as integer "
2580                              "rather than complex due to prototype",
2581                              argnum, rname);
2582                   else if (TREE_CODE (type) == COMPLEX_TYPE
2583                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2584                     warning (0, "passing argument %d of %qE as complex "
2585                              "rather than floating due to prototype",
2586                              argnum, rname);
2587                   else if (TREE_CODE (type) == REAL_TYPE
2588                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2589                     warning (0, "passing argument %d of %qE as floating "
2590                              "rather than integer due to prototype",
2591                              argnum, rname);
2592                   else if (TREE_CODE (type) == COMPLEX_TYPE
2593                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2594                     warning (0, "passing argument %d of %qE as complex "
2595                              "rather than integer due to prototype",
2596                              argnum, rname);
2597                   else if (TREE_CODE (type) == REAL_TYPE
2598                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2599                     warning (0, "passing argument %d of %qE as floating "
2600                              "rather than complex due to prototype",
2601                              argnum, rname);
2602                   /* ??? At some point, messages should be written about
2603                      conversions between complex types, but that's too messy
2604                      to do now.  */
2605                   else if (TREE_CODE (type) == REAL_TYPE
2606                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2607                     {
2608                       /* Warn if any argument is passed as `float',
2609                          since without a prototype it would be `double'.  */
2610                       if (formal_prec == TYPE_PRECISION (float_type_node)
2611                           && type != dfloat32_type_node)
2612                         warning (0, "passing argument %d of %qE as %<float%> "
2613                                  "rather than %<double%> due to prototype",
2614                                  argnum, rname);
2615
2616                       /* Warn if mismatch between argument and prototype
2617                          for decimal float types.  Warn of conversions with
2618                          binary float types and of precision narrowing due to
2619                          prototype. */
2620                       else if (type != TREE_TYPE (val)
2621                                && (type == dfloat32_type_node
2622                                    || type == dfloat64_type_node
2623                                    || type == dfloat128_type_node
2624                                    || TREE_TYPE (val) == dfloat32_type_node
2625                                    || TREE_TYPE (val) == dfloat64_type_node
2626                                    || TREE_TYPE (val) == dfloat128_type_node)
2627                                && (formal_prec
2628                                    <= TYPE_PRECISION (TREE_TYPE (val))
2629                                    || (type == dfloat128_type_node
2630                                        && (TREE_TYPE (val)
2631                                            != dfloat64_type_node
2632                                            && (TREE_TYPE (val)
2633                                                != dfloat32_type_node)))
2634                                    || (type == dfloat64_type_node
2635                                        && (TREE_TYPE (val)
2636                                            != dfloat32_type_node))))
2637                         warning (0, "passing argument %d of %qE as %qT "
2638                                  "rather than %qT due to prototype",
2639                                  argnum, rname, type, TREE_TYPE (val));
2640
2641                     }
2642                   /* Detect integer changing in width or signedness.
2643                      These warnings are only activated with
2644                      -Wtraditional-conversion, not with -Wtraditional.  */
2645                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2646                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2647                     {
2648                       tree would_have_been = default_conversion (val);
2649                       tree type1 = TREE_TYPE (would_have_been);
2650
2651                       if (TREE_CODE (type) == ENUMERAL_TYPE
2652                           && (TYPE_MAIN_VARIANT (type)
2653                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2654                         /* No warning if function asks for enum
2655                            and the actual arg is that enum type.  */
2656                         ;
2657                       else if (formal_prec != TYPE_PRECISION (type1))
2658                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2659                                  "with different width due to prototype",
2660                                  argnum, rname);
2661                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2662                         ;
2663                       /* Don't complain if the formal parameter type
2664                          is an enum, because we can't tell now whether
2665                          the value was an enum--even the same enum.  */
2666                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2667                         ;
2668                       else if (TREE_CODE (val) == INTEGER_CST
2669                                && int_fits_type_p (val, type))
2670                         /* Change in signedness doesn't matter
2671                            if a constant value is unaffected.  */
2672                         ;
2673                       /* If the value is extended from a narrower
2674                          unsigned type, it doesn't matter whether we
2675                          pass it as signed or unsigned; the value
2676                          certainly is the same either way.  */
2677                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2678                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2679                         ;
2680                       else if (TYPE_UNSIGNED (type))
2681                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2682                                  "as unsigned due to prototype",
2683                                  argnum, rname);
2684                       else
2685                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2686                                  "as signed due to prototype", argnum, rname);
2687                     }
2688                 }
2689
2690               parmval = convert_for_assignment (type, val, ic_argpass,
2691                                                 fundecl, function,
2692                                                 parmnum + 1);
2693
2694               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2695                   && INTEGRAL_TYPE_P (type)
2696                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2697                 parmval = default_conversion (parmval);
2698             }
2699           argarray[parmnum] = parmval;
2700         }
2701       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2702                && (TYPE_PRECISION (TREE_TYPE (val))
2703                    < TYPE_PRECISION (double_type_node))
2704                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2705         {
2706           if (type_generic)
2707             argarray[parmnum] = val;
2708           else
2709             /* Convert `float' to `double'.  */
2710             argarray[parmnum] = convert (double_type_node, val);
2711         }
2712       else if ((invalid_func_diag =
2713                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2714         {
2715           error (invalid_func_diag);
2716           return -1;
2717         }
2718       else
2719         /* Convert `short' and `char' to full-size `int'.  */
2720         argarray[parmnum] = default_conversion (val);
2721
2722       if (typetail)
2723         typetail = TREE_CHAIN (typetail);
2724     }
2725
2726   gcc_assert (parmnum == nargs);
2727
2728   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2729     {
2730       error ("too few arguments to function %qE", function);
2731       return -1;
2732     }
2733
2734   return parmnum;
2735 }
2736 \f
2737 /* This is the entry point used by the parser to build unary operators
2738    in the input.  CODE, a tree_code, specifies the unary operator, and
2739    ARG is the operand.  For unary plus, the C parser currently uses
2740    CONVERT_EXPR for code.
2741
2742    LOC is the location to use for the tree generated.
2743 */
2744
2745 struct c_expr
2746 parser_build_unary_op (enum tree_code code, struct c_expr arg, location_t loc)
2747 {
2748   struct c_expr result;
2749
2750   result.value = build_unary_op (loc, code, arg.value, 0);
2751   result.original_code = code;
2752
2753   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2754     overflow_warning (result.value);
2755
2756   return result;
2757 }
2758
2759 /* This is the entry point used by the parser to build binary operators
2760    in the input.  CODE, a tree_code, specifies the binary operator, and
2761    ARG1 and ARG2 are the operands.  In addition to constructing the
2762    expression, we check for operands that were written with other binary
2763    operators in a way that is likely to confuse the user.
2764
2765    LOCATION is the location of the binary operator.  */
2766
2767 struct c_expr
2768 parser_build_binary_op (location_t location, enum tree_code code,
2769                         struct c_expr arg1, struct c_expr arg2)
2770 {
2771   struct c_expr result;
2772
2773   enum tree_code code1 = arg1.original_code;
2774   enum tree_code code2 = arg2.original_code;
2775
2776   result.value = build_binary_op (location, code,
2777                                   arg1.value, arg2.value, 1);
2778   result.original_code = code;
2779
2780   if (TREE_CODE (result.value) == ERROR_MARK)
2781     return result;
2782
2783   if (location != UNKNOWN_LOCATION)
2784     protected_set_expr_location (result.value, location);
2785
2786   /* Check for cases such as x+y<<z which users are likely
2787      to misinterpret.  */
2788   if (warn_parentheses)
2789     warn_about_parentheses (code, code1, arg1.value, code2, arg2.value);
2790
2791   if (TREE_CODE_CLASS (code1) != tcc_comparison)
2792     warn_logical_operator (code, arg1.value, arg2.value);
2793
2794   /* Warn about comparisons against string literals, with the exception
2795      of testing for equality or inequality of a string literal with NULL.  */
2796   if (code == EQ_EXPR || code == NE_EXPR)
2797     {
2798       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2799           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2800         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2801     }
2802   else if (TREE_CODE_CLASS (code) == tcc_comparison
2803            && (code1 == STRING_CST || code2 == STRING_CST))
2804     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2805
2806   if (TREE_OVERFLOW_P (result.value)
2807       && !TREE_OVERFLOW_P (arg1.value)
2808       && !TREE_OVERFLOW_P (arg2.value))
2809     overflow_warning (result.value);
2810
2811   return result;
2812 }
2813 \f
2814 /* Return a tree for the difference of pointers OP0 and OP1.
2815    The resulting tree has type int.  */
2816
2817 static tree
2818 pointer_diff (tree op0, tree op1)
2819 {
2820   tree restype = ptrdiff_type_node;
2821
2822   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2823   tree con0, con1, lit0, lit1;
2824   tree orig_op1 = op1;
2825
2826   if (TREE_CODE (target_type) == VOID_TYPE)
2827     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2828              "pointer of type %<void *%> used in subtraction");
2829   if (TREE_CODE (target_type) == FUNCTION_TYPE)
2830     pedwarn (input_location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
2831              "pointer to a function used in subtraction");
2832
2833   /* If the conversion to ptrdiff_type does anything like widening or
2834      converting a partial to an integral mode, we get a convert_expression
2835      that is in the way to do any simplifications.
2836      (fold-const.c doesn't know that the extra bits won't be needed.
2837      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2838      different mode in place.)
2839      So first try to find a common term here 'by hand'; we want to cover
2840      at least the cases that occur in legal static initializers.  */
2841   if (CONVERT_EXPR_P (op0)
2842       && (TYPE_PRECISION (TREE_TYPE (op0))
2843           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2844     con0 = TREE_OPERAND (op0, 0);
2845   else
2846     con0 = op0;
2847   if (CONVERT_EXPR_P (op1)
2848       && (TYPE_PRECISION (TREE_TYPE (op1))
2849           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2850     con1 = TREE_OPERAND (op1, 0);
2851   else
2852     con1 = op1;
2853
2854   if (TREE_CODE (con0) == PLUS_EXPR)
2855     {
2856       lit0 = TREE_OPERAND (con0, 1);
2857       con0 = TREE_OPERAND (con0, 0);
2858     }
2859   else
2860     lit0 = integer_zero_node;
2861
2862   if (TREE_CODE (con1) == PLUS_EXPR)
2863     {
2864       lit1 = TREE_OPERAND (con1, 1);
2865       con1 = TREE_OPERAND (con1, 0);
2866     }
2867   else
2868     lit1 = integer_zero_node;
2869
2870   if (operand_equal_p (con0, con1, 0))
2871     {
2872       op0 = lit0;
2873       op1 = lit1;
2874     }
2875
2876
2877   /* First do the subtraction as integers;
2878      then drop through to build the divide operator.
2879      Do not do default conversions on the minus operator
2880      in case restype is a short type.  */
2881
2882   op0 = build_binary_op (input_location,
2883                          MINUS_EXPR, convert (restype, op0),
2884                          convert (restype, op1), 0);
2885   /* This generates an error if op1 is pointer to incomplete type.  */
2886   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2887     error ("arithmetic on pointer to an incomplete type");
2888
2889   /* This generates an error if op0 is pointer to incomplete type.  */
2890   op1 = c_size_in_bytes (target_type);
2891
2892   /* Divide by the size, in easiest possible way.  */
2893   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2894 }
2895 \f
2896 /* Construct and perhaps optimize a tree representation
2897    for a unary operation.  CODE, a tree_code, specifies the operation
2898    and XARG is the operand.
2899    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2900    the default promotions (such as from short to int).
2901    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2902    allows non-lvalues; this is only used to handle conversion of non-lvalue
2903    arrays to pointers in C99.
2904
2905    LOCATION is the location of the operator.  */
2906
2907 tree
2908 build_unary_op (location_t location,
2909                 enum tree_code code, tree xarg, int flag)
2910 {
2911   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2912   tree arg = xarg;
2913   tree argtype = 0;
2914   enum tree_code typecode;
2915   tree val;
2916   tree ret = error_mark_node;
2917   int noconvert = flag;
2918   const char *invalid_op_diag;
2919
2920   if (code != ADDR_EXPR)
2921     arg = require_complete_type (arg);
2922
2923   typecode = TREE_CODE (TREE_TYPE (arg));
2924   if (typecode == ERROR_MARK)
2925     return error_mark_node;
2926   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2927     typecode = INTEGER_TYPE;
2928
2929   if ((invalid_op_diag
2930        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2931     {
2932       error_at (location, invalid_op_diag);
2933       return error_mark_node;
2934     }
2935
2936   switch (code)
2937     {
2938     case CONVERT_EXPR:
2939       /* This is used for unary plus, because a CONVERT_EXPR
2940          is enough to prevent anybody from looking inside for
2941          associativity, but won't generate any code.  */
2942       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2943             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2944             || typecode == VECTOR_TYPE))
2945         {
2946           error_at (location, "wrong type argument to unary plus");
2947           return error_mark_node;
2948         }
2949       else if (!noconvert)
2950         arg = default_conversion (arg);
2951       arg = non_lvalue (arg);
2952       break;
2953
2954     case NEGATE_EXPR:
2955       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2956             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2957             || typecode == VECTOR_TYPE))
2958         {
2959           error_at (location, "wrong type argument to unary minus");
2960           return error_mark_node;
2961         }
2962       else if (!noconvert)
2963         arg = default_conversion (arg);
2964       break;
2965
2966     case BIT_NOT_EXPR:
2967       /* ~ works on integer types and non float vectors. */
2968       if (typecode == INTEGER_TYPE
2969           || (typecode == VECTOR_TYPE
2970               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2971         {
2972           if (!noconvert)
2973             arg = default_conversion (arg);
2974         }
2975       else if (typecode == COMPLEX_TYPE)
2976         {
2977           code = CONJ_EXPR;
2978           pedwarn (location, OPT_pedantic,
2979                    "ISO C does not support %<~%> for complex conjugation");
2980           if (!noconvert)
2981             arg = default_conversion (arg);
2982         }
2983       else
2984         {
2985           error_at (location, "wrong type argument to bit-complement");
2986           return error_mark_node;
2987         }
2988       break;
2989
2990     case ABS_EXPR:
2991       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2992         {
2993           error_at (location, "wrong type argument to abs");
2994           return error_mark_node;
2995         }
2996       else if (!noconvert)
2997         arg = default_conversion (arg);
2998       break;
2999
3000     case CONJ_EXPR:
3001       /* Conjugating a real value is a no-op, but allow it anyway.  */
3002       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
3003             || typecode == COMPLEX_TYPE))
3004         {
3005           error_at (location, "wrong type argument to conjugation");
3006           return error_mark_node;
3007         }
3008       else if (!noconvert)
3009         arg = default_conversion (arg);
3010       break;
3011
3012     case TRUTH_NOT_EXPR:
3013       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
3014           && typecode != REAL_TYPE && typecode != POINTER_TYPE
3015           && typecode != COMPLEX_TYPE)
3016         {
3017           error_at (location,
3018                     "wrong type argument to unary exclamation mark");
3019           return error_mark_node;
3020         }
3021       arg = c_objc_common_truthvalue_conversion (location, arg);
3022       ret = invert_truthvalue (arg);
3023       goto return_build_unary_op;
3024
3025     case REALPART_EXPR:
3026       if (TREE_CODE (arg) == COMPLEX_CST)
3027         ret = TREE_REALPART (arg);
3028       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3029         ret = fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3030       else
3031         ret = arg;
3032       goto return_build_unary_op;
3033
3034     case IMAGPART_EXPR:
3035       if (TREE_CODE (arg) == COMPLEX_CST)
3036         ret = TREE_IMAGPART (arg);
3037       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3038         ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
3039       else
3040         ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
3041       goto return_build_unary_op;
3042
3043     case PREINCREMENT_EXPR:
3044     case POSTINCREMENT_EXPR:
3045     case PREDECREMENT_EXPR:
3046     case POSTDECREMENT_EXPR:
3047
3048       /* Increment or decrement the real part of the value,
3049          and don't change the imaginary part.  */
3050       if (typecode == COMPLEX_TYPE)
3051         {
3052           tree real, imag;
3053
3054           pedwarn (location, OPT_pedantic,
3055                    "ISO C does not support %<++%> and %<--%> on complex types");
3056
3057           arg = stabilize_reference (arg);
3058           real = build_unary_op (EXPR_LOCATION (arg), REALPART_EXPR, arg, 1);
3059           imag = build_unary_op (EXPR_LOCATION (arg), IMAGPART_EXPR, arg, 1);
3060           real = build_unary_op (EXPR_LOCATION (arg), code, real, 1);
3061           if (real == error_mark_node || imag == error_mark_node)
3062             return error_mark_node;
3063           ret = build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3064                         real, imag);
3065           goto return_build_unary_op;
3066         }
3067
3068       /* Report invalid types.  */
3069
3070       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3071           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3072         {
3073           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3074             error_at (location, "wrong type argument to increment");
3075           else
3076             error_at (location, "wrong type argument to decrement");
3077
3078           return error_mark_node;
3079         }
3080
3081       {
3082         tree inc;
3083
3084         argtype = TREE_TYPE (arg);
3085
3086         /* Compute the increment.  */
3087
3088         if (typecode == POINTER_TYPE)
3089           {
3090             /* If pointer target is an undefined struct,
3091                we just cannot know how to do the arithmetic.  */
3092             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
3093               {
3094                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3095                   error_at (location,
3096                             "increment of pointer to unknown structure");
3097                 else
3098                   error_at (location,
3099                             "decrement of pointer to unknown structure");
3100               }
3101             else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
3102                      || TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)
3103               {
3104                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3105                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3106                            "wrong type argument to increment");
3107                 else
3108                   pedwarn (location, pedantic ? OPT_pedantic : OPT_Wpointer_arith,
3109                            "wrong type argument to decrement");
3110               }
3111
3112             inc = c_size_in_bytes (TREE_TYPE (argtype));
3113             inc = fold_convert (sizetype, inc);
3114           }
3115         else if (FRACT_MODE_P (TYPE_MODE (argtype)))
3116           {
3117             /* For signed fract types, we invert ++ to -- or
3118                -- to ++, and change inc from 1 to -1, because
3119                it is not possible to represent 1 in signed fract constants.
3120                For unsigned fract types, the result always overflows and
3121                we get an undefined (original) or the maximum value.  */
3122             if (code == PREINCREMENT_EXPR)
3123               code = PREDECREMENT_EXPR;
3124             else if (code == PREDECREMENT_EXPR)
3125               code = PREINCREMENT_EXPR;
3126             else if (code == POSTINCREMENT_EXPR)
3127               code = POSTDECREMENT_EXPR;
3128             else /* code == POSTDECREMENT_EXPR  */
3129               code = POSTINCREMENT_EXPR;
3130
3131             inc = integer_minus_one_node;
3132             inc = convert (argtype, inc);
3133           }
3134         else
3135           {
3136             inc = integer_one_node;
3137             inc = convert (argtype, inc);
3138           }
3139
3140         /* Complain about anything else that is not a true lvalue.  */
3141         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3142                                     || code == POSTINCREMENT_EXPR)
3143                                    ? lv_increment
3144                                    : lv_decrement)))
3145           return error_mark_node;
3146
3147         /* Report a read-only lvalue.  */
3148         if (TREE_READONLY (arg))
3149           {
3150             readonly_error (arg,
3151                             ((code == PREINCREMENT_EXPR
3152                               || code == POSTINCREMENT_EXPR)
3153                              ? lv_increment : lv_decrement));
3154             return error_mark_node;
3155           }
3156
3157         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3158           val = boolean_increment (code, arg);
3159         else
3160           val = build2 (code, TREE_TYPE (arg), arg, inc);
3161         TREE_SIDE_EFFECTS (val) = 1;
3162         if (TREE_CODE (val) != code)
3163           TREE_NO_WARNING (val) = 1;
3164         ret = val;
3165         goto return_build_unary_op;
3166       }
3167
3168     case ADDR_EXPR:
3169       /* Note that this operation never does default_conversion.  */
3170
3171       /* Let &* cancel out to simplify resulting code.  */
3172       if (TREE_CODE (arg) == INDIRECT_REF)
3173         {
3174           /* Don't let this be an lvalue.  */
3175           if (lvalue_p (TREE_OPERAND (arg, 0)))
3176             return non_lvalue (TREE_OPERAND (arg, 0));
3177           ret = TREE_OPERAND (arg, 0);
3178           goto return_build_unary_op;
3179         }
3180
3181       /* For &x[y], return x+y */
3182       if (TREE_CODE (arg) == ARRAY_REF)
3183         {
3184           tree op0 = TREE_OPERAND (arg, 0);
3185           if (!c_mark_addressable (op0))
3186             return error_mark_node;
3187           return build_binary_op (location, PLUS_EXPR,
3188                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3189                                    ? array_to_pointer_conversion (op0)
3190                                    : op0),
3191                                   TREE_OPERAND (arg, 1), 1);
3192         }
3193
3194       /* Anything not already handled and not a true memory reference
3195          or a non-lvalue array is an error.  */
3196       else if (typecode != FUNCTION_TYPE && !flag
3197                && !lvalue_or_else (arg, lv_addressof))
3198         return error_mark_node;
3199
3200       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3201       argtype = TREE_TYPE (arg);
3202
3203       /* If the lvalue is const or volatile, merge that into the type
3204          to which the address will point.  Note that you can't get a
3205          restricted pointer by taking the address of something, so we
3206          only have to deal with `const' and `volatile' here.  */
3207       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3208           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3209           argtype = c_build_type_variant (argtype,
3210                                           TREE_READONLY (arg),
3211                                           TREE_THIS_VOLATILE (arg));
3212
3213       if (!c_mark_addressable (arg))
3214         return error_mark_node;
3215
3216       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3217                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3218
3219       argtype = build_pointer_type (argtype);
3220
3221       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3222          when we have proper support for integer constant expressions.  */
3223       val = get_base_address (arg);
3224       if (val && TREE_CODE (val) == INDIRECT_REF
3225           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3226         {
3227           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3228
3229           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3230           ret = fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3231           goto return_build_unary_op;
3232         }
3233
3234       val = build1 (ADDR_EXPR, argtype, arg);
3235
3236       ret = val;
3237       goto return_build_unary_op;
3238
3239     default:
3240       gcc_unreachable ();
3241     }
3242
3243   if (argtype == 0)
3244     argtype = TREE_TYPE (arg);
3245   ret = require_constant_value ? fold_build1_initializer (code, argtype, arg)
3246                                : fold_build1 (code, argtype, arg);
3247  return_build_unary_op:
3248   gcc_assert (ret != error_mark_node);
3249   protected_set_expr_location (ret, location);
3250   return ret;
3251 }
3252
3253 /* Return nonzero if REF is an lvalue valid for this language.
3254    Lvalues can be assigned, unless their type has TYPE_READONLY.
3255    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3256
3257 static int
3258 lvalue_p (const_tree ref)
3259 {
3260   const enum tree_code code = TREE_CODE (ref);
3261
3262   switch (code)
3263     {
3264     case REALPART_EXPR:
3265     case IMAGPART_EXPR:
3266     case COMPONENT_REF:
3267       return lvalue_p (TREE_OPERAND (ref, 0));
3268
3269     case COMPOUND_LITERAL_EXPR:
3270     case STRING_CST:
3271       return 1;
3272
3273     case INDIRECT_REF:
3274     case ARRAY_REF:
3275     case VAR_DECL:
3276     case PARM_DECL:
3277     case RESULT_DECL:
3278     case ERROR_MARK:
3279       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3280               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3281
3282     case BIND_EXPR:
3283       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3284
3285     default:
3286       return 0;
3287     }
3288 }
3289 \f
3290 /* Give an error for storing in something that is 'const'.  */
3291
3292 static void
3293 readonly_error (tree arg, enum lvalue_use use)
3294 {
3295   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3296               || use == lv_asm);
3297   /* Using this macro rather than (for example) arrays of messages
3298      ensures that all the format strings are checked at compile
3299      time.  */
3300 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3301                                    : (use == lv_increment ? (I)         \
3302                                    : (use == lv_decrement ? (D) : (AS))))
3303   if (TREE_CODE (arg) == COMPONENT_REF)
3304     {
3305       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3306         readonly_error (TREE_OPERAND (arg, 0), use);
3307       else
3308         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3309                              G_("increment of read-only member %qD"),
3310                              G_("decrement of read-only member %qD"),
3311                              G_("read-only member %qD used as %<asm%> output")),
3312                TREE_OPERAND (arg, 1));
3313     }
3314   else if (TREE_CODE (arg) == VAR_DECL)
3315     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3316                          G_("increment of read-only variable %qD"),
3317                          G_("decrement of read-only variable %qD"),
3318                          G_("read-only variable %qD used as %<asm%> output")),
3319            arg);
3320   else
3321     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3322                          G_("increment of read-only location %qE"),
3323                          G_("decrement of read-only location %qE"),
3324                          G_("read-only location %qE used as %<asm%> output")),
3325            arg);
3326 }
3327
3328
3329 /* Return nonzero if REF is an lvalue valid for this language;
3330    otherwise, print an error message and return zero.  USE says
3331    how the lvalue is being used and so selects the error message.  */
3332
3333 static int
3334 lvalue_or_else (const_tree ref, enum lvalue_use use)
3335 {
3336   int win = lvalue_p (ref);
3337
3338   if (!win)
3339     lvalue_error (use);
3340
3341   return win;
3342 }
3343 \f
3344 /* Mark EXP saying that we need to be able to take the
3345    address of it; it should not be allocated in a register.
3346    Returns true if successful.  */
3347
3348 bool
3349 c_mark_addressable (tree exp)
3350 {
3351   tree x = exp;
3352
3353   while (1)
3354     switch (TREE_CODE (x))
3355       {
3356       case COMPONENT_REF:
3357         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3358           {
3359             error
3360               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3361             return false;
3362           }
3363
3364         /* ... fall through ...  */
3365
3366       case ADDR_EXPR:
3367       case ARRAY_REF:
3368       case REALPART_EXPR:
3369       case IMAGPART_EXPR:
3370         x = TREE_OPERAND (x, 0);
3371         break;
3372
3373       case COMPOUND_LITERAL_EXPR:
3374       case CONSTRUCTOR:
3375         TREE_ADDRESSABLE (x) = 1;
3376         return true;
3377
3378       case VAR_DECL:
3379       case CONST_DECL:
3380       case PARM_DECL:
3381       case RESULT_DECL:
3382         if (C_DECL_REGISTER (x)
3383             && DECL_NONLOCAL (x))
3384           {
3385             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3386               {
3387                 error
3388                   ("global register variable %qD used in nested function", x);
3389                 return false;
3390               }
3391             pedwarn (input_location, 0, "register variable %qD used in nested function", x);
3392           }
3393         else if (C_DECL_REGISTER (x))
3394           {
3395             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3396               error ("address of global register variable %qD requested", x);
3397             else
3398               error ("address of register variable %qD requested", x);
3399             return false;
3400           }
3401
3402         /* drops in */
3403       case FUNCTION_DECL:
3404         TREE_ADDRESSABLE (x) = 1;
3405         /* drops out */
3406       default:
3407         return true;
3408     }
3409 }
3410 \f
3411 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3412
3413 tree
3414 build_conditional_expr (tree ifexp, tree op1, tree op2)
3415 {
3416   tree type1;
3417   tree type2;
3418   enum tree_code code1;
3419   enum tree_code code2;
3420   tree result_type = NULL;
3421   tree orig_op1 = op1, orig_op2 = op2;
3422
3423   /* Promote both alternatives.  */
3424
3425   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3426     op1 = default_conversion (op1);
3427   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3428     op2 = default_conversion (op2);
3429
3430   if (TREE_CODE (ifexp) == ERROR_MARK
3431       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3432       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3433     return error_mark_node;
3434
3435   type1 = TREE_TYPE (op1);
3436   code1 = TREE_CODE (type1);
3437   type2 = TREE_TYPE (op2);
3438   code2 = TREE_CODE (type2);
3439
3440   /* C90 does not permit non-lvalue arrays in conditional expressions.
3441      In C99 they will be pointers by now.  */
3442   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3443     {
3444       error ("non-lvalue array in conditional expression");
3445       return error_mark_node;
3446     }
3447
3448   /* Quickly detect the usual case where op1 and op2 have the same type
3449      after promotion.  */
3450   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3451     {
3452       if (type1 == type2)
3453         result_type = type1;
3454       else
3455         result_type = TYPE_MAIN_VARIANT (type1);
3456     }
3457   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3458             || code1 == COMPLEX_TYPE)
3459            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3460                || code2 == COMPLEX_TYPE))
3461     {
3462       result_type = c_common_type (type1, type2);
3463
3464       /* If -Wsign-compare, warn here if type1 and type2 have
3465          different signedness.  We'll promote the signed to unsigned
3466          and later code won't know it used to be different.
3467          Do this check on the original types, so that explicit casts
3468          will be considered, but default promotions won't.  */
3469       if (warn_sign_compare && !skip_evaluation)
3470         {
3471           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3472           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3473
3474           if (unsigned_op1 ^ unsigned_op2)
3475             {
3476               bool ovf;
3477
3478               /* Do not warn if the result type is signed, since the
3479                  signed type will only be chosen if it can represent
3480                  all the values of the unsigned type.  */
3481               if (!TYPE_UNSIGNED (result_type))
3482                 /* OK */;
3483               /* Do not warn if the signed quantity is an unsuffixed
3484                  integer literal (or some static constant expression
3485                  involving such literals) and it is non-negative.  */
3486               else if ((unsigned_op2
3487                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3488                        || (unsigned_op1
3489                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3490                 /* OK */;
3491               else
3492                 warning (OPT_Wsign_compare, "signed and unsigned type in conditional expression");
3493             }
3494         }
3495     }
3496   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3497     {
3498       if (code1 != VOID_TYPE || code2 != VOID_TYPE)
3499         pedwarn (input_location, OPT_pedantic,
3500                  "ISO C forbids conditional expr with only one void side");
3501       result_type = void_type_node;
3502     }
3503   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3504     {
3505       if (comp_target_types (type1, type2))
3506         result_type = common_pointer_type (type1, type2);
3507       else if (null_pointer_constant_p (orig_op1))
3508         result_type = qualify_type (type2, type1);
3509       else if (null_pointer_constant_p (orig_op2))
3510         result_type = qualify_type (type1, type2);
3511       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3512         {
3513           if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3514             pedwarn (input_location, OPT_pedantic,
3515                      "ISO C forbids conditional expr between "
3516                      "%<void *%> and function pointer");
3517           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3518                                                           TREE_TYPE (type2)));
3519         }
3520       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3521         {
3522           if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3523             pedwarn (input_location, OPT_pedantic,
3524                      "ISO C forbids conditional expr between "
3525                      "%<void *%> and function pointer");
3526           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3527                                                           TREE_TYPE (type1)));
3528         }
3529       else
3530         {
3531           pedwarn (input_location, 0,
3532                    "pointer type mismatch in conditional expression");
3533           result_type = build_pointer_type (void_type_node);
3534         }
3535     }
3536   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3537     {
3538       if (!null_pointer_constant_p (orig_op2))
3539         pedwarn (input_location, 0,
3540                  "pointer/integer type mismatch in conditional expression");
3541       else
3542         {
3543           op2 = null_pointer_node;
3544         }
3545       result_type = type1;
3546     }
3547   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3548     {
3549       if (!null_pointer_constant_p (orig_op1))
3550         pedwarn (input_location, 0,
3551                  "pointer/integer type mismatch in conditional expression");
3552       else
3553         {
3554           op1 = null_pointer_node;
3555         }
3556       result_type = type2;
3557     }
3558
3559   if (!result_type)
3560     {
3561       if (flag_cond_mismatch)
3562         result_type = void_type_node;
3563       else
3564         {
3565           error ("type mismatch in conditional expression");
3566           return error_mark_node;
3567         }
3568     }
3569
3570   /* Merge const and volatile flags of the incoming types.  */
3571   result_type
3572     = build_type_variant (result_type,
3573                           TREE_READONLY (op1) || TREE_READONLY (op2),
3574                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3575
3576   if (result_type != TREE_TYPE (op1))
3577     op1 = convert_and_check (result_type, op1);
3578   if (result_type != TREE_TYPE (op2))
3579     op2 = convert_and_check (result_type, op2);
3580
3581   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3582 }
3583 \f
3584 /* Return a compound expression that performs two expressions and
3585    returns the value of the second of them.  */
3586
3587 tree
3588 build_compound_expr (tree expr1, tree expr2)
3589 {
3590   if (!TREE_SIDE_EFFECTS (expr1))
3591     {
3592       /* The left-hand operand of a comma expression is like an expression
3593          statement: with -Wunused, we should warn if it doesn't have
3594          any side-effects, unless it was explicitly cast to (void).  */
3595       if (warn_unused_value)
3596         {
3597           if (VOID_TYPE_P (TREE_TYPE (expr1))
3598               && CONVERT_EXPR_P (expr1))
3599             ; /* (void) a, b */
3600           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3601                    && TREE_CODE (expr1) == COMPOUND_EXPR
3602                    && CONVERT_EXPR_P (TREE_OPERAND (expr1, 1)))
3603             ; /* (void) a, (void) b, c */
3604           else
3605             warning (OPT_Wunused_value,
3606                      "left-hand operand of comma expression has no effect");
3607         }
3608     }
3609
3610   /* With -Wunused, we should also warn if the left-hand operand does have
3611      side-effects, but computes a value which is not used.  For example, in
3612      `foo() + bar(), baz()' the result of the `+' operator is not used,
3613      so we should issue a warning.  */
3614   else if (warn_unused_value)
3615     warn_if_unused_value (expr1, input_location);
3616
3617   if (expr2 == error_mark_node)
3618     return error_mark_node;
3619
3620   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3621 }
3622
3623 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3624
3625 tree
3626 build_c_cast (tree type, tree expr)
3627 {
3628   tree value = expr;
3629
3630   if (type == error_mark_node || expr == error_mark_node)
3631     return error_mark_node;
3632
3633   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3634      only in <protocol> qualifications.  But when constructing cast expressions,
3635      the protocols do matter and must be kept around.  */
3636   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3637     return build1 (NOP_EXPR, type, expr);
3638
3639   type = TYPE_MAIN_VARIANT (type);
3640
3641   if (TREE_CODE (type) == ARRAY_TYPE)
3642     {
3643       error ("cast specifies array type");
3644       return error_mark_node;
3645     }
3646
3647   if (TREE_CODE (type) == FUNCTION_TYPE)
3648     {
3649       error ("cast specifies function type");
3650       return error_mark_node;
3651     }
3652
3653   if (!VOID_TYPE_P (type))
3654     {
3655       value = require_complete_type (value);
3656       if (value == error_mark_node)
3657         return error_mark_node;
3658     }
3659
3660   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3661     {
3662       if (TREE_CODE (type) == RECORD_TYPE
3663           || TREE_CODE (type) == UNION_TYPE)
3664         pedwarn (input_location, OPT_pedantic,
3665                  "ISO C forbids casting nonscalar to the same type");
3666     }
3667   else if (TREE_CODE (type) == UNION_TYPE)
3668     {
3669       tree field;
3670
3671       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3672         if (TREE_TYPE (field) != error_mark_node
3673             && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3674                           TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3675           break;
3676
3677       if (field)
3678         {
3679           tree t;
3680
3681           pedwarn (input_location, OPT_pedantic,
3682                    "ISO C forbids casts to union type");
3683           t = digest_init (type,
3684                            build_constructor_single (type, field, value),
3685                            true, 0);
3686           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3687           return t;
3688         }
3689       error ("cast to union type from type not present in union");
3690       return error_mark_node;
3691     }
3692   else
3693     {
3694       tree otype, ovalue;
3695
3696       if (type == void_type_node)
3697         return build1 (CONVERT_EXPR, type, value);
3698
3699       otype = TREE_TYPE (value);
3700
3701       /* Optionally warn about potentially worrisome casts.  */
3702
3703       if (warn_cast_qual
3704           && TREE_CODE (type) == POINTER_TYPE
3705           && TREE_CODE (otype) == POINTER_TYPE)
3706         {
3707           tree in_type = type;
3708           tree in_otype = otype;
3709           int added = 0;
3710           int discarded = 0;
3711
3712           /* Check that the qualifiers on IN_TYPE are a superset of
3713              the qualifiers of IN_OTYPE.  The outermost level of
3714              POINTER_TYPE nodes is uninteresting and we stop as soon
3715              as we hit a non-POINTER_TYPE node on either type.  */
3716           do
3717             {
3718               in_otype = TREE_TYPE (in_otype);
3719               in_type = TREE_TYPE (in_type);
3720
3721               /* GNU C allows cv-qualified function types.  'const'
3722                  means the function is very pure, 'volatile' means it
3723                  can't return.  We need to warn when such qualifiers
3724                  are added, not when they're taken away.  */
3725               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3726                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3727                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3728               else
3729                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3730             }
3731           while (TREE_CODE (in_type) == POINTER_TYPE
3732                  && TREE_CODE (in_otype) == POINTER_TYPE);
3733
3734           if (added)
3735             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3736
3737           if (discarded)
3738             /* There are qualifiers present in IN_OTYPE that are not
3739                present in IN_TYPE.  */
3740             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3741         }
3742
3743       /* Warn about possible alignment problems.  */
3744       if (STRICT_ALIGNMENT
3745           && TREE_CODE (type) == POINTER_TYPE
3746           && TREE_CODE (otype) == POINTER_TYPE
3747           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3748           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3749           /* Don't warn about opaque types, where the actual alignment
3750              restriction is unknown.  */
3751           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3752                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3753                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3754           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3755         warning (OPT_Wcast_align,
3756                  "cast increases required alignment of target type");
3757
3758       if (TREE_CODE (type) == INTEGER_TYPE
3759           && TREE_CODE (otype) == POINTER_TYPE
3760           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3761       /* Unlike conversion of integers to pointers, where the
3762          warning is disabled for converting constants because
3763          of cases such as SIG_*, warn about converting constant
3764          pointers to integers. In some cases it may cause unwanted
3765          sign extension, and a warning is appropriate.  */
3766         warning (OPT_Wpointer_to_int_cast,
3767                  "cast from pointer to integer of different size");
3768
3769       if (TREE_CODE (value) == CALL_EXPR
3770           && TREE_CODE (type) != TREE_CODE (otype))
3771         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3772                  "to non-matching type %qT", otype, type);
3773
3774       if (TREE_CODE (type) == POINTER_TYPE
3775           && TREE_CODE (otype) == INTEGER_TYPE
3776           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3777           /* Don't warn about converting any constant.  */
3778           && !TREE_CONSTANT (value))
3779         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3780                  "of different size");
3781
3782       if (warn_strict_aliasing <= 2)
3783         strict_aliasing_warning (otype, type, expr);
3784
3785       /* If pedantic, warn for conversions between function and object
3786          pointer types, except for converting a null pointer constant
3787          to function pointer type.  */
3788       if (pedantic
3789           && TREE_CODE (type) == POINTER_TYPE
3790           && TREE_CODE (otype) == POINTER_TYPE
3791           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3792           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3793         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3794                  "conversion of function pointer to object pointer type");
3795
3796       if (pedantic
3797           && TREE_CODE (type) == POINTER_TYPE
3798           && TREE_CODE (otype) == POINTER_TYPE
3799           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3800           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3801           && !null_pointer_constant_p (value))
3802         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
3803                  "conversion of object pointer to function pointer type");
3804
3805       ovalue = value;
3806       value = convert (type, value);
3807
3808       /* Ignore any integer overflow caused by the cast.  */
3809       if (TREE_CODE (value) == INTEGER_CST)
3810         {
3811           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3812             {
3813               if (!TREE_OVERFLOW (value))
3814                 {
3815                   /* Avoid clobbering a shared constant.  */
3816                   value = copy_node (value);
3817                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3818                 }
3819             }
3820           else if (TREE_OVERFLOW (value))
3821             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3822             value = build_int_cst_wide (TREE_TYPE (value),
3823                                         TREE_INT_CST_LOW (value),
3824                                         TREE_INT_CST_HIGH (value));
3825         }
3826     }
3827
3828   /* Don't let a cast be an lvalue.  */
3829   if (value == expr)
3830     value = non_lvalue (value);
3831
3832   return value;
3833 }
3834
3835 /* Interpret a cast of expression EXPR to type TYPE.  */
3836 tree
3837 c_cast_expr (struct c_type_name *type_name, tree expr)
3838 {
3839   tree type;
3840   int saved_wsp = warn_strict_prototypes;
3841
3842   /* This avoids warnings about unprototyped casts on
3843      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3844   if (TREE_CODE (expr) == INTEGER_CST)
3845     warn_strict_prototypes = 0;
3846   type = groktypename (type_name);
3847   warn_strict_prototypes = saved_wsp;
3848
3849   return build_c_cast (type, expr);
3850 }
3851 \f
3852 /* Build an assignment expression of lvalue LHS from value RHS.
3853    MODIFYCODE is the code for a binary operator that we use
3854    to combine the old value of LHS with RHS to get the new value.
3855    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
3856
3857    LOCATION is the location of the MODIFYCODE operator.  */
3858
3859 tree
3860 build_modify_expr (location_t location,
3861                    tree lhs, enum tree_code modifycode, tree rhs)
3862 {
3863   tree result;
3864   tree newrhs;
3865   tree lhstype = TREE_TYPE (lhs);
3866   tree olhstype = lhstype;
3867
3868   /* Types that aren't fully specified cannot be used in assignments.  */
3869   lhs = require_complete_type (lhs);
3870
3871   /* Avoid duplicate error messages from operands that had errors.  */
3872   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3873     return error_mark_node;
3874
3875   if (!lvalue_or_else (lhs, lv_assign))
3876     return error_mark_node;
3877
3878   STRIP_TYPE_NOPS (rhs);
3879
3880   newrhs = rhs;
3881
3882   /* If a binary op has been requested, combine the old LHS value with the RHS
3883      producing the value we should actually store into the LHS.  */
3884
3885   if (modifycode != NOP_EXPR)
3886     {
3887       lhs = stabilize_reference (lhs);
3888       newrhs = build_binary_op (location,
3889                                 modifycode, lhs, rhs, 1);
3890     }
3891
3892   /* Give an error for storing in something that is 'const'.  */
3893
3894   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3895       || ((TREE_CODE (lhstype) == RECORD_TYPE
3896            || TREE_CODE (lhstype) == UNION_TYPE)
3897           && C_TYPE_FIELDS_READONLY (lhstype)))
3898     {
3899       readonly_error (lhs, lv_assign);
3900       return error_mark_node;
3901     }
3902
3903   /* If storing into a structure or union member,
3904      it has probably been given type `int'.
3905      Compute the type that would go with
3906      the actual amount of storage the member occupies.  */
3907
3908   if (TREE_CODE (lhs) == COMPONENT_REF
3909       && (TREE_CODE (lhstype) == INTEGER_TYPE
3910           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3911           || TREE_CODE (lhstype) == REAL_TYPE
3912           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3913     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3914
3915   /* If storing in a field that is in actuality a short or narrower than one,
3916      we must store in the field in its actual type.  */
3917
3918   if (lhstype != TREE_TYPE (lhs))
3919     {
3920       lhs = copy_node (lhs);
3921       TREE_TYPE (lhs) = lhstype;
3922     }
3923
3924   /* Convert new value to destination type.  */
3925
3926   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3927                                    NULL_TREE, NULL_TREE, 0);
3928   if (TREE_CODE (newrhs) == ERROR_MARK)
3929     return error_mark_node;
3930
3931   /* Emit ObjC write barrier, if necessary.  */
3932   if (c_dialect_objc () && flag_objc_gc)
3933     {
3934       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3935       if (result)
3936         {
3937           protected_set_expr_location (result, location);
3938           return result;
3939         }
3940     }
3941
3942   /* Scan operands.  */
3943
3944   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3945   TREE_SIDE_EFFECTS (result) = 1;
3946   protected_set_expr_location (result, location);
3947
3948   /* If we got the LHS in a different type for storing in,
3949      convert the result back to the nominal type of LHS
3950      so that the value we return always has the same type
3951      as the LHS argument.  */
3952
3953   if (olhstype == TREE_TYPE (result))
3954     return result;
3955
3956   result = convert_for_assignment (olhstype, result, ic_assign,
3957                                    NULL_TREE, NULL_TREE, 0);
3958   protected_set_expr_location (result, location);
3959   return result;
3960 }
3961 \f
3962 /* Convert value RHS to type TYPE as preparation for an assignment
3963    to an lvalue of type TYPE.
3964    The real work of conversion is done by `convert'.
3965    The purpose of this function is to generate error messages
3966    for assignments that are not allowed in C.
3967    ERRTYPE says whether it is argument passing, assignment,
3968    initialization or return.
3969
3970    FUNCTION is a tree for the function being called.
3971    PARMNUM is the number of the argument, for printing in error messages.  */
3972
3973 static tree
3974 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3975                         tree fundecl, tree function, int parmnum)
3976 {
3977   enum tree_code codel = TREE_CODE (type);
3978   tree rhstype;
3979   enum tree_code coder;
3980   tree rname = NULL_TREE;
3981   bool objc_ok = false;
3982
3983   if (errtype == ic_argpass)
3984     {
3985       tree selector;
3986       /* Change pointer to function to the function itself for
3987          diagnostics.  */
3988       if (TREE_CODE (function) == ADDR_EXPR
3989           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3990         function = TREE_OPERAND (function, 0);
3991
3992       /* Handle an ObjC selector specially for diagnostics.  */
3993       selector = objc_message_selector ();
3994       rname = function;
3995       if (selector && parmnum > 2)
3996         {
3997           rname = selector;
3998           parmnum -= 2;
3999         }
4000     }
4001
4002   /* This macro is used to emit diagnostics to ensure that all format
4003      strings are complete sentences, visible to gettext and checked at
4004      compile time.  */
4005 #define WARN_FOR_ASSIGNMENT(LOCATION, OPT, AR, AS, IN, RE)               \
4006   do {                                                                   \
4007     switch (errtype)                                                     \
4008       {                                                                  \
4009       case ic_argpass:                                                   \
4010         if (pedwarn (LOCATION, OPT, AR, parmnum, rname))                 \
4011           inform ((fundecl && !DECL_IS_BUILTIN (fundecl))                \
4012                   ? DECL_SOURCE_LOCATION (fundecl) : LOCATION,           \
4013                   "expected %qT but argument is of type %qT",            \
4014                   type, rhstype);                                        \
4015         break;                                                           \
4016       case ic_assign:                                                    \
4017         pedwarn (LOCATION, OPT, AS);                                     \
4018         break;                                                           \
4019       case ic_init:                                                      \
4020         pedwarn (LOCATION, OPT, IN);                                     \
4021         break;                                                           \
4022       case ic_return:                                                    \
4023         pedwarn (LOCATION, OPT, RE);                                     \
4024         break;                                                           \
4025       default:                                                           \
4026         gcc_unreachable ();                                              \
4027       }                                                                  \
4028   } while (0)
4029
4030   STRIP_TYPE_NOPS (rhs);
4031
4032   if (optimize && TREE_CODE (rhs) == VAR_DECL
4033            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
4034     rhs = decl_constant_value_for_broken_optimization (rhs);
4035
4036   rhstype = TREE_TYPE (rhs);
4037   coder = TREE_CODE (rhstype);
4038
4039   if (coder == ERROR_MARK)
4040     return error_mark_node;
4041
4042   if (c_dialect_objc ())
4043     {
4044       int parmno;
4045
4046       switch (errtype)
4047         {
4048         case ic_return:
4049           parmno = 0;
4050           break;
4051
4052         case ic_assign:
4053           parmno = -1;
4054           break;
4055
4056         case ic_init:
4057           parmno = -2;
4058           break;
4059
4060         default:
4061           parmno = parmnum;
4062           break;
4063         }
4064
4065       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
4066     }
4067
4068   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
4069     return rhs;
4070
4071   if (coder == VOID_TYPE)
4072     {
4073       /* Except for passing an argument to an unprototyped function,
4074          this is a constraint violation.  When passing an argument to
4075          an unprototyped function, it is compile-time undefined;
4076          making it a constraint in that case was rejected in
4077          DR#252.  */
4078       error ("void value not ignored as it ought to be");
4079       return error_mark_node;
4080     }
4081   rhs = require_complete_type (rhs);
4082   if (rhs == error_mark_node)
4083     return error_mark_node;
4084   /* A type converts to a reference to it.
4085      This code doesn't fully support references, it's just for the
4086      special case of va_start and va_copy.  */
4087   if (codel == REFERENCE_TYPE
4088       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4089     {
4090       if (!lvalue_p (rhs))
4091         {
4092           error ("cannot pass rvalue to reference parameter");
4093           return error_mark_node;
4094         }
4095       if (!c_mark_addressable (rhs))
4096         return error_mark_node;
4097       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4098
4099       /* We already know that these two types are compatible, but they
4100          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4101          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4102          likely to be va_list, a typedef to __builtin_va_list, which
4103          is different enough that it will cause problems later.  */
4104       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4105         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4106
4107       rhs = build1 (NOP_EXPR, type, rhs);
4108       return rhs;
4109     }
4110   /* Some types can interconvert without explicit casts.  */
4111   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4112            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4113     return convert (type, rhs);
4114   /* Arithmetic types all interconvert, and enum is treated like int.  */
4115   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4116             || codel == FIXED_POINT_TYPE
4117             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4118             || codel == BOOLEAN_TYPE)
4119            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4120                || coder == FIXED_POINT_TYPE
4121                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4122                || coder == BOOLEAN_TYPE))
4123     return convert_and_check (type, rhs);
4124
4125   /* Aggregates in different TUs might need conversion.  */
4126   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4127       && codel == coder
4128       && comptypes (type, rhstype))
4129     return convert_and_check (type, rhs);
4130
4131   /* Conversion to a transparent union from its member types.
4132      This applies only to function arguments.  */
4133   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4134       && errtype == ic_argpass)
4135     {
4136       tree memb, marginal_memb = NULL_TREE;
4137
4138       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4139         {
4140           tree memb_type = TREE_TYPE (memb);
4141
4142           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4143                          TYPE_MAIN_VARIANT (rhstype)))
4144             break;
4145
4146           if (TREE_CODE (memb_type) != POINTER_TYPE)
4147             continue;
4148
4149           if (coder == POINTER_TYPE)
4150             {
4151               tree ttl = TREE_TYPE (memb_type);
4152               tree ttr = TREE_TYPE (rhstype);
4153
4154               /* Any non-function converts to a [const][volatile] void *
4155                  and vice versa; otherwise, targets must be the same.
4156                  Meanwhile, the lhs target must have all the qualifiers of
4157                  the rhs.  */
4158               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4159                   || comp_target_types (memb_type, rhstype))
4160                 {
4161                   /* If this type won't generate any warnings, use it.  */
4162                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4163                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4164                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4165                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4166                              == TYPE_QUALS (ttr))
4167                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4168                              == TYPE_QUALS (ttl))))
4169                     break;
4170
4171                   /* Keep looking for a better type, but remember this one.  */
4172                   if (!marginal_memb)
4173                     marginal_memb = memb;
4174                 }
4175             }
4176
4177           /* Can convert integer zero to any pointer type.  */
4178           if (null_pointer_constant_p (rhs))
4179             {
4180               rhs = null_pointer_node;
4181               break;
4182             }
4183         }
4184
4185       if (memb || marginal_memb)
4186         {
4187           if (!memb)
4188             {
4189               /* We have only a marginally acceptable member type;
4190                  it needs a warning.  */
4191               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4192               tree ttr = TREE_TYPE (rhstype);
4193
4194               /* Const and volatile mean something different for function
4195                  types, so the usual warnings are not appropriate.  */
4196               if (TREE_CODE (ttr) == FUNCTION_TYPE
4197                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4198                 {
4199                   /* Because const and volatile on functions are
4200                      restrictions that say the function will not do
4201                      certain things, it is okay to use a const or volatile
4202                      function where an ordinary one is wanted, but not
4203                      vice-versa.  */
4204                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4205                     WARN_FOR_ASSIGNMENT (input_location, 0,
4206                                          G_("passing argument %d of %qE "
4207                                             "makes qualified function "
4208                                             "pointer from unqualified"),
4209                                          G_("assignment makes qualified "
4210                                             "function pointer from "
4211                                             "unqualified"),
4212                                          G_("initialization makes qualified "
4213                                             "function pointer from "
4214                                             "unqualified"),
4215                                          G_("return makes qualified function "
4216                                             "pointer from unqualified"));
4217                 }
4218               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4219                 WARN_FOR_ASSIGNMENT (input_location, 0,
4220                                      G_("passing argument %d of %qE discards "
4221                                         "qualifiers from pointer target type"),
4222                                      G_("assignment discards qualifiers "
4223                                         "from pointer target type"),
4224                                      G_("initialization discards qualifiers "
4225                                         "from pointer target type"),
4226                                      G_("return discards qualifiers from "
4227                                         "pointer target type"));
4228
4229               memb = marginal_memb;
4230             }
4231
4232           if (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl))
4233             pedwarn (input_location, OPT_pedantic,
4234                      "ISO C prohibits argument conversion to union type");
4235
4236           rhs = fold_convert (TREE_TYPE (memb), rhs);
4237           return build_constructor_single (type, memb, rhs);
4238         }
4239     }
4240
4241   /* Conversions among pointers */
4242   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4243            && (coder == codel))
4244     {
4245       tree ttl = TREE_TYPE (type);
4246       tree ttr = TREE_TYPE (rhstype);
4247       tree mvl = ttl;
4248       tree mvr = ttr;
4249       bool is_opaque_pointer;
4250       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4251
4252       if (TREE_CODE (mvl) != ARRAY_TYPE)
4253         mvl = TYPE_MAIN_VARIANT (mvl);
4254       if (TREE_CODE (mvr) != ARRAY_TYPE)
4255         mvr = TYPE_MAIN_VARIANT (mvr);
4256       /* Opaque pointers are treated like void pointers.  */
4257       is_opaque_pointer = vector_targets_convertible_p (ttl, ttr);
4258
4259       /* C++ does not allow the implicit conversion void* -> T*.  However,
4260          for the purpose of reducing the number of false positives, we
4261          tolerate the special case of
4262
4263                 int *p = NULL;
4264
4265          where NULL is typically defined in C to be '(void *) 0'.  */
4266       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4267         warning (OPT_Wc___compat, "request for implicit conversion from "
4268                  "%qT to %qT not permitted in C++", rhstype, type);
4269
4270       /* Check if the right-hand side has a format attribute but the
4271          left-hand side doesn't.  */
4272       if (warn_missing_format_attribute
4273           && check_missing_format_attribute (type, rhstype))
4274         {
4275           switch (errtype)
4276           {
4277           case ic_argpass:
4278             warning (OPT_Wmissing_format_attribute,
4279                      "argument %d of %qE might be "
4280                      "a candidate for a format attribute",
4281                      parmnum, rname);
4282             break;
4283           case ic_assign:
4284             warning (OPT_Wmissing_format_attribute,
4285                      "assignment left-hand side might be "
4286                      "a candidate for a format attribute");
4287             break;
4288           case ic_init:
4289             warning (OPT_Wmissing_format_attribute,
4290                      "initialization left-hand side might be "
4291                      "a candidate for a format attribute");
4292             break;
4293           case ic_return:
4294             warning (OPT_Wmissing_format_attribute,
4295                      "return type might be "
4296                      "a candidate for a format attribute");
4297             break;
4298           default:
4299             gcc_unreachable ();
4300           }
4301         }
4302
4303       /* Any non-function converts to a [const][volatile] void *
4304          and vice versa; otherwise, targets must be the same.
4305          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4306       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4307           || (target_cmp = comp_target_types (type, rhstype))
4308           || is_opaque_pointer
4309           || (c_common_unsigned_type (mvl)
4310               == c_common_unsigned_type (mvr)))
4311         {
4312           if (pedantic
4313               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4314                   ||
4315                   (VOID_TYPE_P (ttr)
4316                    && !null_pointer_constant_p (rhs)
4317                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4318             WARN_FOR_ASSIGNMENT (input_location, OPT_pedantic,
4319                                  G_("ISO C forbids passing argument %d of "
4320                                     "%qE between function pointer "
4321                                     "and %<void *%>"),
4322                                  G_("ISO C forbids assignment between "
4323                                     "function pointer and %<void *%>"),
4324                                  G_("ISO C forbids initialization between "
4325                                     "function pointer and %<void *%>"),
4326                                  G_("ISO C forbids return between function "
4327                                     "pointer and %<void *%>"));
4328           /* Const and volatile mean something different for function types,
4329              so the usual warnings are not appropriate.  */
4330           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4331                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4332             {
4333               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4334                 {
4335                   /* Types differing only by the presence of the 'volatile'
4336                      qualifier are acceptable if the 'volatile' has been added
4337                      in by the Objective-C EH machinery.  */
4338                   if (!objc_type_quals_match (ttl, ttr))
4339                     WARN_FOR_ASSIGNMENT (input_location, 0,
4340                                          G_("passing argument %d of %qE discards "
4341                                             "qualifiers from pointer target type"),
4342                                          G_("assignment discards qualifiers "
4343                                             "from pointer target type"),
4344                                          G_("initialization discards qualifiers "
4345                                             "from pointer target type"),
4346                                          G_("return discards qualifiers from "
4347                                             "pointer target type"));
4348                 }
4349               /* If this is not a case of ignoring a mismatch in signedness,
4350                  no warning.  */
4351               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4352                        || target_cmp)
4353                 ;
4354               /* If there is a mismatch, do warn.  */
4355               else if (warn_pointer_sign)
4356                 WARN_FOR_ASSIGNMENT (input_location, OPT_Wpointer_sign,
4357                                      G_("pointer targets in passing argument "
4358                                         "%d of %qE differ in signedness"),
4359                                      G_("pointer targets in assignment "
4360                                         "differ in signedness"),
4361                                      G_("pointer targets in initialization "
4362                                         "differ in signedness"),
4363                                      G_("pointer targets in return differ "
4364                                         "in signedness"));
4365             }
4366           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4367                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4368             {
4369               /* Because const and volatile on functions are restrictions
4370                  that say the function will not do certain things,
4371                  it is okay to use a const or volatile function
4372                  where an ordinary one is wanted, but not vice-versa.  */
4373               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4374                 WARN_FOR_ASSIGNMENT (input_location, 0,
4375                                      G_("passing argument %d of %qE makes "
4376                                         "qualified function pointer "
4377                                         "from unqualified"),
4378                                      G_("assignment makes qualified function "
4379                                         "pointer from unqualified"),
4380                                      G_("initialization makes qualified "
4381                                         "function pointer from unqualified"),
4382                                      G_("return makes qualified function "
4383                                         "pointer from unqualified"));
4384             }
4385         }
4386       else
4387         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4388         if (!objc_ok)
4389           WARN_FOR_ASSIGNMENT (input_location, 0,
4390                                G_("passing argument %d of %qE from "
4391                                   "incompatible pointer type"),
4392                                G_("assignment from incompatible pointer type"),
4393                                G_("initialization from incompatible "
4394                                   "pointer type"),
4395                                G_("return from incompatible pointer type"));
4396
4397       return convert (type, rhs);
4398     }
4399   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4400     {
4401       /* ??? This should not be an error when inlining calls to
4402          unprototyped functions.  */
4403       error ("invalid use of non-lvalue array");
4404       return error_mark_node;
4405     }
4406   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4407     {
4408       /* An explicit constant 0 can convert to a pointer,
4409          or one that results from arithmetic, even including
4410          a cast to integer type.  */
4411       if (!null_pointer_constant_p (rhs))
4412         WARN_FOR_ASSIGNMENT (input_location, 0,
4413                              G_("passing argument %d of %qE makes "
4414                                 "pointer from integer without a cast"),
4415                              G_("assignment makes pointer from integer "
4416                                 "without a cast"),
4417                              G_("initialization makes pointer from "
4418                                 "integer without a cast"),
4419                              G_("return makes pointer from integer "
4420                                 "without a cast"));
4421
4422       return convert (type, rhs);
4423     }
4424   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4425     {
4426       WARN_FOR_ASSIGNMENT (input_location, 0,
4427                            G_("passing argument %d of %qE makes integer "
4428                               "from pointer without a cast"),
4429                            G_("assignment makes integer from pointer "
4430                               "without a cast"),
4431                            G_("initialization makes integer from pointer "
4432                               "without a cast"),
4433                            G_("return makes integer from pointer "
4434                               "without a cast"));
4435       return convert (type, rhs);
4436     }
4437   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4438     return convert (type, rhs);
4439
4440   switch (errtype)
4441     {
4442     case ic_argpass:
4443       error ("incompatible type for argument %d of %qE", parmnum, rname);
4444       inform ((fundecl && !DECL_IS_BUILTIN (fundecl))
4445               ? DECL_SOURCE_LOCATION (fundecl) : input_location,
4446               "expected %qT but argument is of type %qT", type, rhstype);
4447       break;
4448     case ic_assign:
4449       error ("incompatible types when assigning to type %qT from type %qT",
4450              type, rhstype);
4451       break;
4452     case ic_init:
4453       error ("incompatible types when initializing type %qT using type %qT",
4454              type, rhstype);
4455       break;
4456     case ic_return:
4457       error ("incompatible types when returning type %qT but %qT was expected",
4458              rhstype, type);
4459       break;
4460     default:
4461       gcc_unreachable ();
4462     }
4463
4464   return error_mark_node;
4465 }
4466 \f
4467 /* If VALUE is a compound expr all of whose expressions are constant, then
4468    return its value.  Otherwise, return error_mark_node.
4469
4470    This is for handling COMPOUND_EXPRs as initializer elements
4471    which is allowed with a warning when -pedantic is specified.  */
4472
4473 static tree
4474 valid_compound_expr_initializer (tree value, tree endtype)
4475 {
4476   if (TREE_CODE (value) == COMPOUND_EXPR)
4477     {
4478       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4479           == error_mark_node)
4480         return error_mark_node;
4481       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4482                                               endtype);
4483     }
4484   else if (!initializer_constant_valid_p (value, endtype))
4485     return error_mark_node;
4486   else
4487     return value;
4488 }
4489 \f
4490 /* Perform appropriate conversions on the initial value of a variable,
4491    store it in the declaration DECL,
4492    and print any error messages that are appropriate.
4493    If the init is invalid, store an ERROR_MARK.  */
4494
4495 void
4496 store_init_value (tree decl, tree init)
4497 {
4498   tree value, type;
4499
4500   /* If variable's type was invalidly declared, just ignore it.  */
4501
4502   type = TREE_TYPE (decl);
4503   if (TREE_CODE (type) == ERROR_MARK)
4504     return;
4505
4506   /* Digest the specified initializer into an expression.  */
4507
4508   value = digest_init (type, init, true, TREE_STATIC (decl));
4509
4510   /* Store the expression if valid; else report error.  */
4511
4512   if (!in_system_header
4513       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4514     warning (OPT_Wtraditional, "traditional C rejects automatic "
4515              "aggregate initialization");
4516
4517   DECL_INITIAL (decl) = value;
4518
4519   /* ANSI wants warnings about out-of-range constant initializers.  */
4520   STRIP_TYPE_NOPS (value);
4521   if (TREE_STATIC (decl))
4522     constant_expression_warning (value);
4523
4524   /* Check if we need to set array size from compound literal size.  */
4525   if (TREE_CODE (type) == ARRAY_TYPE
4526       && TYPE_DOMAIN (type) == 0
4527       && value != error_mark_node)
4528     {
4529       tree inside_init = init;
4530
4531       STRIP_TYPE_NOPS (inside_init);
4532       inside_init = fold (inside_init);
4533
4534       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4535         {
4536           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4537
4538           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4539             {
4540               /* For int foo[] = (int [3]){1}; we need to set array size
4541                  now since later on array initializer will be just the
4542                  brace enclosed list of the compound literal.  */
4543               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4544               TREE_TYPE (decl) = type;
4545               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4546               layout_type (type);
4547               layout_decl (cldecl, 0);
4548             }
4549         }
4550     }
4551 }
4552 \f
4553 /* Methods for storing and printing names for error messages.  */
4554
4555 /* Implement a spelling stack that allows components of a name to be pushed
4556    and popped.  Each element on the stack is this structure.  */
4557
4558 struct spelling
4559 {
4560   int kind;
4561   union
4562     {
4563       unsigned HOST_WIDE_INT i;
4564       const char *s;
4565     } u;
4566 };
4567
4568 #define SPELLING_STRING 1
4569 #define SPELLING_MEMBER 2
4570 #define SPELLING_BOUNDS 3
4571
4572 static struct spelling *spelling;       /* Next stack element (unused).  */
4573 static struct spelling *spelling_base;  /* Spelling stack base.  */
4574 static int spelling_size;               /* Size of the spelling stack.  */
4575
4576 /* Macros to save and restore the spelling stack around push_... functions.
4577    Alternative to SAVE_SPELLING_STACK.  */
4578
4579 #define SPELLING_DEPTH() (spelling - spelling_base)
4580 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4581
4582 /* Push an element on the spelling stack with type KIND and assign VALUE
4583    to MEMBER.  */
4584
4585 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4586 {                                                                       \
4587   int depth = SPELLING_DEPTH ();                                        \
4588                                                                         \
4589   if (depth >= spelling_size)                                           \
4590     {                                                                   \
4591       spelling_size += 10;                                              \
4592       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4593                                   spelling_size);                       \
4594       RESTORE_SPELLING_DEPTH (depth);                                   \
4595     }                                                                   \
4596                                                                         \
4597   spelling->kind = (KIND);                                              \
4598   spelling->MEMBER = (VALUE);                                           \
4599   spelling++;                                                           \
4600 }
4601
4602 /* Push STRING on the stack.  Printed literally.  */
4603
4604 static void
4605 push_string (const char *string)
4606 {
4607   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4608 }
4609
4610 /* Push a member name on the stack.  Printed as '.' STRING.  */
4611
4612 static void
4613 push_member_name (tree decl)
4614 {
4615   const char *const string
4616     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4617   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4618 }
4619
4620 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4621
4622 static void
4623 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4624 {
4625   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4626 }
4627
4628 /* Compute the maximum size in bytes of the printed spelling.  */
4629
4630 static int
4631 spelling_length (void)
4632 {
4633   int size = 0;
4634   struct spelling *p;
4635
4636   for (p = spelling_base; p < spelling; p++)
4637     {
4638       if (p->kind == SPELLING_BOUNDS)
4639         size += 25;
4640       else
4641         size += strlen (p->u.s) + 1;
4642     }
4643
4644   return size;
4645 }
4646
4647 /* Print the spelling to BUFFER and return it.  */
4648
4649 static char *
4650 print_spelling (char *buffer)
4651 {
4652   char *d = buffer;
4653   struct spelling *p;
4654
4655   for (p = spelling_base; p < spelling; p++)
4656     if (p->kind == SPELLING_BOUNDS)
4657       {
4658         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4659         d += strlen (d);
4660       }
4661     else
4662       {
4663         const char *s;
4664         if (p->kind == SPELLING_MEMBER)
4665           *d++ = '.';
4666         for (s = p->u.s; (*d = *s++); d++)
4667           ;
4668       }
4669   *d++ = '\0';
4670   return buffer;
4671 }
4672
4673 /* Issue an error message for a bad initializer component.
4674    MSGID identifies the message.
4675    The component name is taken from the spelling stack.  */
4676
4677 void
4678 error_init (const char *msgid)
4679 {
4680   char *ofwhat;
4681
4682   error ("%s", _(msgid));
4683   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4684   if (*ofwhat)
4685     error ("(near initialization for %qs)", ofwhat);
4686 }
4687
4688 /* Issue a pedantic warning for a bad initializer component.  OPT is
4689    the option OPT_* (from options.h) controlling this warning or 0 if
4690    it is unconditionally given.  MSGID identifies the message.  The
4691    component name is taken from the spelling stack.  */
4692
4693 void
4694 pedwarn_init (location_t location, int opt, const char *msgid)
4695 {
4696   char *ofwhat;
4697
4698   pedwarn (location, opt, "%s", _(msgid));
4699   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4700   if (*ofwhat)
4701     pedwarn (location, opt, "(near initialization for %qs)", ofwhat);
4702 }
4703
4704 /* Issue a warning for a bad initializer component.
4705
4706    OPT is the OPT_W* value corresponding to the warning option that
4707    controls this warning.  MSGID identifies the message.  The
4708    component name is taken from the spelling stack.  */
4709
4710 static void
4711 warning_init (int opt, const char *msgid)
4712 {
4713   char *ofwhat;
4714
4715   warning (opt, "%s", _(msgid));
4716   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4717   if (*ofwhat)
4718     warning (opt, "(near initialization for %qs)", ofwhat);
4719 }
4720 \f
4721 /* If TYPE is an array type and EXPR is a parenthesized string
4722    constant, warn if pedantic that EXPR is being used to initialize an
4723    object of type TYPE.  */
4724
4725 void
4726 maybe_warn_string_init (tree type, struct c_expr expr)
4727 {
4728   if (pedantic
4729       && TREE_CODE (type) == ARRAY_TYPE
4730       && TREE_CODE (expr.value) == STRING_CST
4731       && expr.original_code != STRING_CST)
4732     pedwarn_init (input_location, OPT_pedantic,
4733                   "array initialized from parenthesized string constant");
4734 }
4735
4736 /* Digest the parser output INIT as an initializer for type TYPE.
4737    Return a C expression of type TYPE to represent the initial value.
4738
4739    If INIT is a string constant, STRICT_STRING is true if it is
4740    unparenthesized or we should not warn here for it being parenthesized.
4741    For other types of INIT, STRICT_STRING is not used.
4742
4743    REQUIRE_CONSTANT requests an error if non-constant initializers or
4744    elements are seen.  */
4745
4746 static tree
4747 digest_init (tree type, tree init, bool strict_string, int require_constant)
4748 {
4749   enum tree_code code = TREE_CODE (type);
4750   tree inside_init = init;
4751
4752   if (type == error_mark_node
4753       || !init
4754       || init == error_mark_node
4755       || TREE_TYPE (init) == error_mark_node)
4756     return error_mark_node;
4757
4758   STRIP_TYPE_NOPS (inside_init);
4759
4760   inside_init = fold (inside_init);
4761
4762   /* Initialization of an array of chars from a string constant
4763      optionally enclosed in braces.  */
4764
4765   if (code == ARRAY_TYPE && inside_init
4766       && TREE_CODE (inside_init) == STRING_CST)
4767     {
4768       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4769       /* Note that an array could be both an array of character type
4770          and an array of wchar_t if wchar_t is signed char or unsigned
4771          char.  */
4772       bool char_array = (typ1 == char_type_node
4773                          || typ1 == signed_char_type_node
4774                          || typ1 == unsigned_char_type_node);
4775       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4776       bool char16_array = !!comptypes (typ1, char16_type_node);
4777       bool char32_array = !!comptypes (typ1, char32_type_node);
4778
4779       if (char_array || wchar_array || char16_array || char32_array)
4780         {
4781           struct c_expr expr;
4782           tree typ2 = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)));
4783           expr.value = inside_init;
4784           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4785           maybe_warn_string_init (type, expr);
4786
4787           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4788                          TYPE_MAIN_VARIANT (type)))
4789             return inside_init;
4790
4791           if (char_array)
4792             {
4793               if (typ2 != char_type_node)
4794                 {
4795                   error_init ("char-array initialized from wide string");
4796                   return error_mark_node;
4797                 }
4798             }
4799           else
4800             {
4801               if (typ2 == char_type_node)
4802                 {
4803                   error_init ("wide character array initialized from non-wide "
4804                               "string");
4805                   return error_mark_node;
4806                 }
4807               else if (!comptypes(typ1, typ2))
4808                 {
4809                   error_init ("wide character array initialized from "
4810                               "incompatible wide string");
4811                   return error_mark_node;
4812                 }
4813             }
4814
4815           TREE_TYPE (inside_init) = type;
4816           if (TYPE_DOMAIN (type) != 0
4817               && TYPE_SIZE (type) != 0
4818               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4819               /* Subtract the size of a single (possibly wide) character
4820                  because it's ok to ignore the terminating null char
4821                  that is counted in the length of the constant.  */
4822               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4823                                        TREE_STRING_LENGTH (inside_init)
4824                                        - (TYPE_PRECISION (typ1)
4825                                           / BITS_PER_UNIT)))
4826             pedwarn_init (input_location, 0,
4827                           "initializer-string for array of chars is too long");
4828
4829           return inside_init;
4830         }
4831       else if (INTEGRAL_TYPE_P (typ1))
4832         {
4833           error_init ("array of inappropriate type initialized "
4834                       "from string constant");
4835           return error_mark_node;
4836         }
4837     }
4838
4839   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4840      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4841      below and handle as a constructor.  */
4842   if (code == VECTOR_TYPE
4843       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4844       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4845       && TREE_CONSTANT (inside_init))
4846     {
4847       if (TREE_CODE (inside_init) == VECTOR_CST
4848           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4849                         TYPE_MAIN_VARIANT (type)))
4850         return inside_init;
4851
4852       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4853         {
4854           unsigned HOST_WIDE_INT ix;
4855           tree value;
4856           bool constant_p = true;
4857
4858           /* Iterate through elements and check if all constructor
4859              elements are *_CSTs.  */
4860           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4861             if (!CONSTANT_CLASS_P (value))
4862               {
4863                 constant_p = false;
4864                 break;
4865               }
4866
4867           if (constant_p)
4868             return build_vector_from_ctor (type,
4869                                            CONSTRUCTOR_ELTS (inside_init));
4870         }
4871     }
4872
4873   if (warn_sequence_point)
4874     verify_sequence_points (inside_init);
4875
4876   /* Any type can be initialized
4877      from an expression of the same type, optionally with braces.  */
4878
4879   if (inside_init && TREE_TYPE (inside_init) != 0
4880       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4881                      TYPE_MAIN_VARIANT (type))
4882           || (code == ARRAY_TYPE
4883               && comptypes (TREE_TYPE (inside_init), type))
4884           || (code == VECTOR_TYPE
4885               && comptypes (TREE_TYPE (inside_init), type))
4886           || (code == POINTER_TYPE
4887               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4888               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4889                             TREE_TYPE (type)))))
4890     {
4891       if (code == POINTER_TYPE)
4892         {
4893           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4894             {
4895               if (TREE_CODE (inside_init) == STRING_CST
4896                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4897                 inside_init = array_to_pointer_conversion (inside_init);
4898               else
4899                 {
4900                   error_init ("invalid use of non-lvalue array");
4901                   return error_mark_node;
4902                 }
4903             }
4904         }
4905
4906       if (code == VECTOR_TYPE)
4907         /* Although the types are compatible, we may require a
4908            conversion.  */
4909         inside_init = convert (type, inside_init);
4910
4911       if (require_constant
4912           && (code == VECTOR_TYPE || !flag_isoc99)
4913           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4914         {
4915           /* As an extension, allow initializing objects with static storage
4916              duration with compound literals (which are then treated just as
4917              the brace enclosed list they contain).  Also allow this for
4918              vectors, as we can only assign them with compound literals.  */
4919           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4920           inside_init = DECL_INITIAL (decl);
4921         }
4922
4923       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4924           && TREE_CODE (inside_init) != CONSTRUCTOR)
4925         {
4926           error_init ("array initialized from non-constant array expression");
4927           return error_mark_node;
4928         }
4929
4930       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4931         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4932
4933       /* Compound expressions can only occur here if -pedantic or
4934          -pedantic-errors is specified.  In the later case, we always want
4935          an error.  In the former case, we simply want a warning.  */
4936       if (require_constant && pedantic
4937           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4938         {
4939           inside_init
4940             = valid_compound_expr_initializer (inside_init,
4941                                                TREE_TYPE (inside_init));
4942           if (inside_init == error_mark_node)
4943             error_init ("initializer element is not constant");
4944           else
4945             pedwarn_init (input_location, OPT_pedantic,
4946                           "initializer element is not constant");
4947           if (flag_pedantic_errors)
4948             inside_init = error_mark_node;
4949         }
4950       else if (require_constant
4951                && !initializer_constant_valid_p (inside_init,
4952                                                  TREE_TYPE (inside_init)))
4953         {
4954           error_init ("initializer element is not constant");
4955           inside_init = error_mark_node;
4956         }
4957
4958       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4959       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4960         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4961                                               NULL_TREE, 0);
4962       return inside_init;
4963     }
4964
4965   /* Handle scalar types, including conversions.  */
4966
4967   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4968       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4969       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4970     {
4971       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4972           && (TREE_CODE (init) == STRING_CST
4973               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4974         init = array_to_pointer_conversion (init);
4975       inside_init
4976         = convert_for_assignment (type, init, ic_init,
4977                                   NULL_TREE, NULL_TREE, 0);
4978
4979       /* Check to see if we have already given an error message.  */
4980       if (inside_init == error_mark_node)
4981         ;
4982       else if (require_constant && !TREE_CONSTANT (inside_init))
4983         {
4984           error_init ("initializer element is not constant");
4985           inside_init = error_mark_node;
4986         }
4987       else if (require_constant
4988                && !initializer_constant_valid_p (inside_init,
4989                                                  TREE_TYPE (inside_init)))
4990         {
4991           error_init ("initializer element is not computable at load time");
4992           inside_init = error_mark_node;
4993         }
4994
4995       return inside_init;
4996     }
4997
4998   /* Come here only for records and arrays.  */
4999
5000   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
5001     {
5002       error_init ("variable-sized object may not be initialized");
5003       return error_mark_node;
5004     }
5005
5006   error_init ("invalid initializer");
5007   return error_mark_node;
5008 }
5009 \f
5010 /* Handle initializers that use braces.  */
5011
5012 /* Type of object we are accumulating a constructor for.
5013    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
5014 static tree constructor_type;
5015
5016 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
5017    left to fill.  */
5018 static tree constructor_fields;
5019
5020 /* For an ARRAY_TYPE, this is the specified index
5021    at which to store the next element we get.  */
5022 static tree constructor_index;
5023
5024 /* For an ARRAY_TYPE, this is the maximum index.  */
5025 static tree constructor_max_index;
5026
5027 /* For a RECORD_TYPE, this is the first field not yet written out.  */
5028 static tree constructor_unfilled_fields;
5029
5030 /* For an ARRAY_TYPE, this is the index of the first element
5031    not yet written out.  */
5032 static tree constructor_unfilled_index;
5033
5034 /* In a RECORD_TYPE, the byte index of the next consecutive field.
5035    This is so we can generate gaps between fields, when appropriate.  */
5036 static tree constructor_bit_index;
5037
5038 /* If we are saving up the elements rather than allocating them,
5039    this is the list of elements so far (in reverse order,
5040    most recent first).  */
5041 static VEC(constructor_elt,gc) *constructor_elements;
5042
5043 /* 1 if constructor should be incrementally stored into a constructor chain,
5044    0 if all the elements should be kept in AVL tree.  */
5045 static int constructor_incremental;
5046
5047 /* 1 if so far this constructor's elements are all compile-time constants.  */
5048 static int constructor_constant;
5049
5050 /* 1 if so far this constructor's elements are all valid address constants.  */
5051 static int constructor_simple;
5052
5053 /* 1 if this constructor is erroneous so far.  */
5054 static int constructor_erroneous;
5055
5056 /* Structure for managing pending initializer elements, organized as an
5057    AVL tree.  */
5058
5059 struct init_node
5060 {
5061   struct init_node *left, *right;
5062   struct init_node *parent;
5063   int balance;
5064   tree purpose;
5065   tree value;
5066 };
5067
5068 /* Tree of pending elements at this constructor level.
5069    These are elements encountered out of order
5070    which belong at places we haven't reached yet in actually
5071    writing the output.
5072    Will never hold tree nodes across GC runs.  */
5073 static struct init_node *constructor_pending_elts;
5074
5075 /* The SPELLING_DEPTH of this constructor.  */
5076 static int constructor_depth;
5077
5078 /* DECL node for which an initializer is being read.
5079    0 means we are reading a constructor expression
5080    such as (struct foo) {...}.  */
5081 static tree constructor_decl;
5082
5083 /* Nonzero if this is an initializer for a top-level decl.  */
5084 static int constructor_top_level;
5085
5086 /* Nonzero if there were any member designators in this initializer.  */
5087 static int constructor_designated;
5088
5089 /* Nesting depth of designator list.  */
5090 static int designator_depth;
5091
5092 /* Nonzero if there were diagnosed errors in this designator list.  */
5093 static int designator_erroneous;
5094
5095 \f
5096 /* This stack has a level for each implicit or explicit level of
5097    structuring in the initializer, including the outermost one.  It
5098    saves the values of most of the variables above.  */
5099
5100 struct constructor_range_stack;
5101
5102 struct constructor_stack
5103 {
5104   struct constructor_stack *next;
5105   tree type;
5106   tree fields;
5107   tree index;
5108   tree max_index;
5109   tree unfilled_index;
5110   tree unfilled_fields;
5111   tree bit_index;
5112   VEC(constructor_elt,gc) *elements;
5113   struct init_node *pending_elts;
5114   int offset;
5115   int depth;
5116   /* If value nonzero, this value should replace the entire
5117      constructor at this level.  */
5118   struct c_expr replacement_value;
5119   struct constructor_range_stack *range_stack;
5120   char constant;
5121   char simple;
5122   char implicit;
5123   char erroneous;
5124   char outer;
5125   char incremental;
5126   char designated;
5127 };
5128
5129 static struct constructor_stack *constructor_stack;
5130
5131 /* This stack represents designators from some range designator up to
5132    the last designator in the list.  */
5133
5134 struct constructor_range_stack
5135 {
5136   struct constructor_range_stack *next, *prev;
5137   struct constructor_stack *stack;
5138   tree range_start;
5139   tree index;
5140   tree range_end;
5141   tree fields;
5142 };
5143
5144 static struct constructor_range_stack *constructor_range_stack;
5145
5146 /* This stack records separate initializers that are nested.
5147    Nested initializers can't happen in ANSI C, but GNU C allows them
5148    in cases like { ... (struct foo) { ... } ... }.  */
5149
5150 struct initializer_stack
5151 {
5152   struct initializer_stack *next;
5153   tree decl;
5154   struct constructor_stack *constructor_stack;
5155   struct constructor_range_stack *constructor_range_stack;
5156   VEC(constructor_elt,gc) *elements;
5157   struct spelling *spelling;
5158   struct spelling *spelling_base;
5159   int spelling_size;
5160   char top_level;
5161   char require_constant_value;
5162   char require_constant_elements;
5163 };
5164
5165 static struct initializer_stack *initializer_stack;
5166 \f
5167 /* Prepare to parse and output the initializer for variable DECL.  */
5168
5169 void
5170 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5171 {
5172   const char *locus;
5173   struct initializer_stack *p = XNEW (struct initializer_stack);
5174
5175   p->decl = constructor_decl;
5176   p->require_constant_value = require_constant_value;
5177   p->require_constant_elements = require_constant_elements;
5178   p->constructor_stack = constructor_stack;
5179   p->constructor_range_stack = constructor_range_stack;
5180   p->elements = constructor_elements;
5181   p->spelling = spelling;
5182   p->spelling_base = spelling_base;
5183   p->spelling_size = spelling_size;
5184   p->top_level = constructor_top_level;
5185   p->next = initializer_stack;
5186   initializer_stack = p;
5187
5188   constructor_decl = decl;
5189   constructor_designated = 0;
5190   constructor_top_level = top_level;
5191
5192   if (decl != 0 && decl != error_mark_node)
5193     {
5194       require_constant_value = TREE_STATIC (decl);
5195       require_constant_elements
5196         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5197            /* For a scalar, you can always use any value to initialize,
5198               even within braces.  */
5199            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5200                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5201                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5202                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5203       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5204     }
5205   else
5206     {
5207       require_constant_value = 0;
5208       require_constant_elements = 0;
5209       locus = "(anonymous)";
5210     }
5211
5212   constructor_stack = 0;
5213   constructor_range_stack = 0;
5214
5215   missing_braces_mentioned = 0;
5216
5217   spelling_base = 0;
5218   spelling_size = 0;
5219   RESTORE_SPELLING_DEPTH (0);
5220
5221   if (locus)
5222     push_string (locus);
5223 }
5224
5225 void
5226 finish_init (void)
5227 {
5228   struct initializer_stack *p = initializer_stack;
5229
5230   /* Free the whole constructor stack of this initializer.  */
5231   while (constructor_stack)
5232     {
5233       struct constructor_stack *q = constructor_stack;
5234       constructor_stack = q->next;
5235       free (q);
5236     }
5237
5238   gcc_assert (!constructor_range_stack);
5239
5240   /* Pop back to the data of the outer initializer (if any).  */
5241   free (spelling_base);
5242
5243   constructor_decl = p->decl;
5244   require_constant_value = p->require_constant_value;
5245   require_constant_elements = p->require_constant_elements;
5246   constructor_stack = p->constructor_stack;
5247   constructor_range_stack = p->constructor_range_stack;
5248   constructor_elements = p->elements;
5249   spelling = p->spelling;
5250   spelling_base = p->spelling_base;
5251   spelling_size = p->spelling_size;
5252   constructor_top_level = p->top_level;
5253   initializer_stack = p->next;
5254   free (p);
5255 }
5256 \f
5257 /* Call here when we see the initializer is surrounded by braces.
5258    This is instead of a call to push_init_level;
5259    it is matched by a call to pop_init_level.
5260
5261    TYPE is the type to initialize, for a constructor expression.
5262    For an initializer for a decl, TYPE is zero.  */
5263
5264 void
5265 really_start_incremental_init (tree type)
5266 {
5267   struct constructor_stack *p = XNEW (struct constructor_stack);
5268
5269   if (type == 0)
5270     type = TREE_TYPE (constructor_decl);
5271
5272   if (targetm.vector_opaque_p (type))
5273     error ("opaque vector types cannot be initialized");
5274
5275   p->type = constructor_type;
5276   p->fields = constructor_fields;
5277   p->index = constructor_index;
5278   p->max_index = constructor_max_index;
5279   p->unfilled_index = constructor_unfilled_index;
5280   p->unfilled_fields = constructor_unfilled_fields;
5281   p->bit_index = constructor_bit_index;
5282   p->elements = constructor_elements;
5283   p->constant = constructor_constant;
5284   p->simple = constructor_simple;
5285   p->erroneous = constructor_erroneous;
5286   p->pending_elts = constructor_pending_elts;
5287   p->depth = constructor_depth;
5288   p->replacement_value.value = 0;
5289   p->replacement_value.original_code = ERROR_MARK;
5290   p->implicit = 0;
5291   p->range_stack = 0;
5292   p->outer = 0;
5293   p->incremental = constructor_incremental;
5294   p->designated = constructor_designated;
5295   p->next = 0;
5296   constructor_stack = p;
5297
5298   constructor_constant = 1;
5299   constructor_simple = 1;
5300   constructor_depth = SPELLING_DEPTH ();
5301   constructor_elements = 0;
5302   constructor_pending_elts = 0;
5303   constructor_type = type;
5304   constructor_incremental = 1;
5305   constructor_designated = 0;
5306   designator_depth = 0;
5307   designator_erroneous = 0;
5308
5309   if (TREE_CODE (constructor_type) == RECORD_TYPE
5310       || TREE_CODE (constructor_type) == UNION_TYPE)
5311     {
5312       constructor_fields = TYPE_FIELDS (constructor_type);
5313       /* Skip any nameless bit fields at the beginning.  */
5314       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5315              && DECL_NAME (constructor_fields) == 0)
5316         constructor_fields = TREE_CHAIN (constructor_fields);
5317
5318       constructor_unfilled_fields = constructor_fields;
5319       constructor_bit_index = bitsize_zero_node;
5320     }
5321   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5322     {
5323       if (TYPE_DOMAIN (constructor_type))
5324         {
5325           constructor_max_index
5326             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5327
5328           /* Detect non-empty initializations of zero-length arrays.  */
5329           if (constructor_max_index == NULL_TREE
5330               && TYPE_SIZE (constructor_type))
5331             constructor_max_index = build_int_cst (NULL_TREE, -1);
5332
5333           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5334              to initialize VLAs will cause a proper error; avoid tree
5335              checking errors as well by setting a safe value.  */
5336           if (constructor_max_index
5337               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5338             constructor_max_index = build_int_cst (NULL_TREE, -1);
5339
5340           constructor_index
5341             = convert (bitsizetype,
5342                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5343         }
5344       else
5345         {
5346           constructor_index = bitsize_zero_node;
5347           constructor_max_index = NULL_TREE;
5348         }
5349
5350       constructor_unfilled_index = constructor_index;
5351     }
5352   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5353     {
5354       /* Vectors are like simple fixed-size arrays.  */
5355       constructor_max_index =
5356         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5357       constructor_index = bitsize_zero_node;
5358       constructor_unfilled_index = constructor_index;
5359     }
5360   else
5361     {
5362       /* Handle the case of int x = {5}; */
5363       constructor_fields = constructor_type;
5364       constructor_unfilled_fields = constructor_type;
5365     }
5366 }
5367 \f
5368 /* Push down into a subobject, for initialization.
5369    If this is for an explicit set of braces, IMPLICIT is 0.
5370    If it is because the next element belongs at a lower level,
5371    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5372
5373 void
5374 push_init_level (int implicit)
5375 {
5376   struct constructor_stack *p;
5377   tree value = NULL_TREE;
5378
5379   /* If we've exhausted any levels that didn't have braces,
5380      pop them now.  If implicit == 1, this will have been done in
5381      process_init_element; do not repeat it here because in the case
5382      of excess initializers for an empty aggregate this leads to an
5383      infinite cycle of popping a level and immediately recreating
5384      it.  */
5385   if (implicit != 1)
5386     {
5387       while (constructor_stack->implicit)
5388         {
5389           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5390                || TREE_CODE (constructor_type) == UNION_TYPE)
5391               && constructor_fields == 0)
5392             process_init_element (pop_init_level (1));
5393           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5394                    && constructor_max_index
5395                    && tree_int_cst_lt (constructor_max_index,
5396                                        constructor_index))
5397             process_init_element (pop_init_level (1));
5398           else
5399             break;
5400         }
5401     }
5402
5403   /* Unless this is an explicit brace, we need to preserve previous
5404      content if any.  */
5405   if (implicit)
5406     {
5407       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5408            || TREE_CODE (constructor_type) == UNION_TYPE)
5409           && constructor_fields)
5410         value = find_init_member (constructor_fields);
5411       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5412         value = find_init_member (constructor_index);
5413     }
5414
5415   p = XNEW (struct constructor_stack);
5416   p->type = constructor_type;
5417   p->fields = constructor_fields;
5418   p->index = constructor_index;
5419   p->max_index = constructor_max_index;
5420   p->unfilled_index = constructor_unfilled_index;
5421   p->unfilled_fields = constructor_unfilled_fields;
5422   p->bit_index = constructor_bit_index;
5423   p->elements = constructor_elements;
5424   p->constant = constructor_constant;
5425   p->simple = constructor_simple;
5426   p->erroneous = constructor_erroneous;
5427   p->pending_elts = constructor_pending_elts;
5428   p->depth = constructor_depth;
5429   p->replacement_value.value = 0;
5430   p->replacement_value.original_code = ERROR_MARK;
5431   p->implicit = implicit;
5432   p->outer = 0;
5433   p->incremental = constructor_incremental;
5434   p->designated = constructor_designated;
5435   p->next = constructor_stack;
5436   p->range_stack = 0;
5437   constructor_stack = p;
5438
5439   constructor_constant = 1;
5440   constructor_simple = 1;
5441   constructor_depth = SPELLING_DEPTH ();
5442   constructor_elements = 0;
5443   constructor_incremental = 1;
5444   constructor_designated = 0;
5445   constructor_pending_elts = 0;
5446   if (!implicit)
5447     {
5448       p->range_stack = constructor_range_stack;
5449       constructor_range_stack = 0;
5450       designator_depth = 0;
5451       designator_erroneous = 0;
5452     }
5453
5454   /* Don't die if an entire brace-pair level is superfluous
5455      in the containing level.  */
5456   if (constructor_type == 0)
5457     ;
5458   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5459            || TREE_CODE (constructor_type) == UNION_TYPE)
5460     {
5461       /* Don't die if there are extra init elts at the end.  */
5462       if (constructor_fields == 0)
5463         constructor_type = 0;
5464       else
5465         {
5466           constructor_type = TREE_TYPE (constructor_fields);
5467           push_member_name (constructor_fields);
5468           constructor_depth++;
5469         }
5470     }
5471   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5472     {
5473       constructor_type = TREE_TYPE (constructor_type);
5474       push_array_bounds (tree_low_cst (constructor_index, 1));
5475       constructor_depth++;
5476     }
5477
5478   if (constructor_type == 0)
5479     {
5480       error_init ("extra brace group at end of initializer");
5481       constructor_fields = 0;
5482       constructor_unfilled_fields = 0;
5483       return;
5484     }
5485
5486   if (value && TREE_CODE (value) == CONSTRUCTOR)
5487     {
5488       constructor_constant = TREE_CONSTANT (value);
5489       constructor_simple = TREE_STATIC (value);
5490       constructor_elements = CONSTRUCTOR_ELTS (value);
5491       if (!VEC_empty (constructor_elt, constructor_elements)
5492           && (TREE_CODE (constructor_type) == RECORD_TYPE
5493               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5494         set_nonincremental_init ();
5495     }
5496
5497   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5498     {
5499       missing_braces_mentioned = 1;
5500       warning_init (OPT_Wmissing_braces, "missing braces around initializer");
5501     }
5502
5503   if (TREE_CODE (constructor_type) == RECORD_TYPE
5504            || TREE_CODE (constructor_type) == UNION_TYPE)
5505     {
5506       constructor_fields = TYPE_FIELDS (constructor_type);
5507       /* Skip any nameless bit fields at the beginning.  */
5508       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5509              && DECL_NAME (constructor_fields) == 0)
5510         constructor_fields = TREE_CHAIN (constructor_fields);
5511
5512       constructor_unfilled_fields = constructor_fields;
5513       constructor_bit_index = bitsize_zero_node;
5514     }
5515   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5516     {
5517       /* Vectors are like simple fixed-size arrays.  */
5518       constructor_max_index =
5519         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5520       constructor_index = convert (bitsizetype, integer_zero_node);
5521       constructor_unfilled_index = constructor_index;
5522     }
5523   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5524     {
5525       if (TYPE_DOMAIN (constructor_type))
5526         {
5527           constructor_max_index
5528             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5529
5530           /* Detect non-empty initializations of zero-length arrays.  */
5531           if (constructor_max_index == NULL_TREE
5532               && TYPE_SIZE (constructor_type))
5533             constructor_max_index = build_int_cst (NULL_TREE, -1);
5534
5535           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5536              to initialize VLAs will cause a proper error; avoid tree
5537              checking errors as well by setting a safe value.  */
5538           if (constructor_max_index
5539               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5540             constructor_max_index = build_int_cst (NULL_TREE, -1);
5541
5542           constructor_index
5543             = convert (bitsizetype,
5544                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5545         }
5546       else
5547         constructor_index = bitsize_zero_node;
5548
5549       constructor_unfilled_index = constructor_index;
5550       if (value && TREE_CODE (value) == STRING_CST)
5551         {
5552           /* We need to split the char/wchar array into individual
5553              characters, so that we don't have to special case it
5554              everywhere.  */
5555           set_nonincremental_init_from_string (value);
5556         }
5557     }
5558   else
5559     {
5560       if (constructor_type != error_mark_node)
5561         warning_init (0, "braces around scalar initializer");
5562       constructor_fields = constructor_type;
5563       constructor_unfilled_fields = constructor_type;
5564     }
5565 }
5566
5567 /* At the end of an implicit or explicit brace level,
5568    finish up that level of constructor.  If a single expression
5569    with redundant braces initialized that level, return the
5570    c_expr structure for that expression.  Otherwise, the original_code
5571    element is set to ERROR_MARK.
5572    If we were outputting the elements as they are read, return 0 as the value
5573    from inner levels (process_init_element ignores that),
5574    but return error_mark_node as the value from the outermost level
5575    (that's what we want to put in DECL_INITIAL).
5576    Otherwise, return a CONSTRUCTOR expression as the value.  */
5577
5578 struct c_expr
5579 pop_init_level (int implicit)
5580 {
5581   struct constructor_stack *p;
5582   struct c_expr ret;
5583   ret.value = 0;
5584   ret.original_code = ERROR_MARK;
5585
5586   if (implicit == 0)
5587     {
5588       /* When we come to an explicit close brace,
5589          pop any inner levels that didn't have explicit braces.  */
5590       while (constructor_stack->implicit)
5591         process_init_element (pop_init_level (1));
5592
5593       gcc_assert (!constructor_range_stack);
5594     }
5595
5596   /* Now output all pending elements.  */
5597   constructor_incremental = 1;
5598   output_pending_init_elements (1);
5599
5600   p = constructor_stack;
5601
5602   /* Error for initializing a flexible array member, or a zero-length
5603      array member in an inappropriate context.  */
5604   if (constructor_type && constructor_fields
5605       && TREE_CODE (constructor_type) == ARRAY_TYPE
5606       && TYPE_DOMAIN (constructor_type)
5607       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5608     {
5609       /* Silently discard empty initializations.  The parser will
5610          already have pedwarned for empty brackets.  */
5611       if (integer_zerop (constructor_unfilled_index))
5612         constructor_type = NULL_TREE;
5613       else
5614         {
5615           gcc_assert (!TYPE_SIZE (constructor_type));
5616
5617           if (constructor_depth > 2)
5618             error_init ("initialization of flexible array member in a nested context");
5619           else
5620             pedwarn_init (input_location, OPT_pedantic,
5621                           "initialization of a flexible array member");
5622
5623           /* We have already issued an error message for the existence
5624              of a flexible array member not at the end of the structure.
5625              Discard the initializer so that we do not die later.  */
5626           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5627             constructor_type = NULL_TREE;
5628         }
5629     }
5630
5631   /* Warn when some struct elements are implicitly initialized to zero.  */
5632   if (warn_missing_field_initializers
5633       && constructor_type
5634       && TREE_CODE (constructor_type) == RECORD_TYPE
5635       && constructor_unfilled_fields)
5636     {
5637         /* Do not warn for flexible array members or zero-length arrays.  */
5638         while (constructor_unfilled_fields
5639                && (!DECL_SIZE (constructor_unfilled_fields)
5640                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5641           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5642
5643         /* Do not warn if this level of the initializer uses member
5644            designators; it is likely to be deliberate.  */
5645         if (constructor_unfilled_fields && !constructor_designated)
5646           {
5647             push_member_name (constructor_unfilled_fields);
5648             warning_init (OPT_Wmissing_field_initializers,
5649                           "missing initializer");
5650             RESTORE_SPELLING_DEPTH (constructor_depth);
5651           }
5652     }
5653
5654   /* Pad out the end of the structure.  */
5655   if (p->replacement_value.value)
5656     /* If this closes a superfluous brace pair,
5657        just pass out the element between them.  */
5658     ret = p->replacement_value;
5659   else if (constructor_type == 0)
5660     ;
5661   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5662            && TREE_CODE (constructor_type) != UNION_TYPE
5663            && TREE_CODE (constructor_type) != ARRAY_TYPE
5664            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5665     {
5666       /* A nonincremental scalar initializer--just return
5667          the element, after verifying there is just one.  */
5668       if (VEC_empty (constructor_elt,constructor_elements))
5669         {
5670           if (!constructor_erroneous)
5671             error_init ("empty scalar initializer");
5672           ret.value = error_mark_node;
5673         }
5674       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5675         {
5676           error_init ("extra elements in scalar initializer");
5677           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5678         }
5679       else
5680         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5681     }
5682   else
5683     {
5684       if (constructor_erroneous)
5685         ret.value = error_mark_node;
5686       else
5687         {
5688           ret.value = build_constructor (constructor_type,
5689                                          constructor_elements);
5690           if (constructor_constant)
5691             TREE_CONSTANT (ret.value) = 1;
5692           if (constructor_constant && constructor_simple)
5693             TREE_STATIC (ret.value) = 1;
5694         }
5695     }
5696
5697   constructor_type = p->type;
5698   constructor_fields = p->fields;
5699   constructor_index = p->index;
5700   constructor_max_index = p->max_index;
5701   constructor_unfilled_index = p->unfilled_index;
5702   constructor_unfilled_fields = p->unfilled_fields;
5703   constructor_bit_index = p->bit_index;
5704   constructor_elements = p->elements;
5705   constructor_constant = p->constant;
5706   constructor_simple = p->simple;
5707   constructor_erroneous = p->erroneous;
5708   constructor_incremental = p->incremental;
5709   constructor_designated = p->designated;
5710   constructor_pending_elts = p->pending_elts;
5711   constructor_depth = p->depth;
5712   if (!p->implicit)
5713     constructor_range_stack = p->range_stack;
5714   RESTORE_SPELLING_DEPTH (constructor_depth);
5715
5716   constructor_stack = p->next;
5717   free (p);
5718
5719   if (ret.value == 0 && constructor_stack == 0)
5720     ret.value = error_mark_node;
5721   return ret;
5722 }
5723
5724 /* Common handling for both array range and field name designators.
5725    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5726
5727 static int
5728 set_designator (int array)
5729 {
5730   tree subtype;
5731   enum tree_code subcode;
5732
5733   /* Don't die if an entire brace-pair level is superfluous
5734      in the containing level.  */
5735   if (constructor_type == 0)
5736     return 1;
5737
5738   /* If there were errors in this designator list already, bail out
5739      silently.  */
5740   if (designator_erroneous)
5741     return 1;
5742
5743   if (!designator_depth)
5744     {
5745       gcc_assert (!constructor_range_stack);
5746
5747       /* Designator list starts at the level of closest explicit
5748          braces.  */
5749       while (constructor_stack->implicit)
5750         process_init_element (pop_init_level (1));
5751       constructor_designated = 1;
5752       return 0;
5753     }
5754
5755   switch (TREE_CODE (constructor_type))
5756     {
5757     case  RECORD_TYPE:
5758     case  UNION_TYPE:
5759       subtype = TREE_TYPE (constructor_fields);
5760       if (subtype != error_mark_node)
5761         subtype = TYPE_MAIN_VARIANT (subtype);
5762       break;
5763     case ARRAY_TYPE:
5764       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5765       break;
5766     default:
5767       gcc_unreachable ();
5768     }
5769
5770   subcode = TREE_CODE (subtype);
5771   if (array && subcode != ARRAY_TYPE)
5772     {
5773       error_init ("array index in non-array initializer");
5774       return 1;
5775     }
5776   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5777     {
5778       error_init ("field name not in record or union initializer");
5779       return 1;
5780     }
5781
5782   constructor_designated = 1;
5783   push_init_level (2);
5784   return 0;
5785 }
5786
5787 /* If there are range designators in designator list, push a new designator
5788    to constructor_range_stack.  RANGE_END is end of such stack range or
5789    NULL_TREE if there is no range designator at this level.  */
5790
5791 static void
5792 push_range_stack (tree range_end)
5793 {
5794   struct constructor_range_stack *p;
5795
5796   p = GGC_NEW (struct constructor_range_stack);
5797   p->prev = constructor_range_stack;
5798   p->next = 0;
5799   p->fields = constructor_fields;
5800   p->range_start = constructor_index;
5801   p->index = constructor_index;
5802   p->stack = constructor_stack;
5803   p->range_end = range_end;
5804   if (constructor_range_stack)
5805     constructor_range_stack->next = p;
5806   constructor_range_stack = p;
5807 }
5808
5809 /* Within an array initializer, specify the next index to be initialized.
5810    FIRST is that index.  If LAST is nonzero, then initialize a range
5811    of indices, running from FIRST through LAST.  */
5812
5813 void
5814 set_init_index (tree first, tree last)
5815 {
5816   if (set_designator (1))
5817     return;
5818
5819   designator_erroneous = 1;
5820
5821   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5822       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5823     {
5824       error_init ("array index in initializer not of integer type");
5825       return;
5826     }
5827
5828   if (TREE_CODE (first) != INTEGER_CST)
5829     error_init ("nonconstant array index in initializer");
5830   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5831     error_init ("nonconstant array index in initializer");
5832   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5833     error_init ("array index in non-array initializer");
5834   else if (tree_int_cst_sgn (first) == -1)
5835     error_init ("array index in initializer exceeds array bounds");
5836   else if (constructor_max_index
5837            && tree_int_cst_lt (constructor_max_index, first))
5838     error_init ("array index in initializer exceeds array bounds");
5839   else
5840     {
5841       constructor_index = convert (bitsizetype, first);
5842
5843       if (last)
5844         {
5845           if (tree_int_cst_equal (first, last))
5846             last = 0;
5847           else if (tree_int_cst_lt (last, first))
5848             {
5849               error_init ("empty index range in initializer");
5850               last = 0;
5851             }
5852           else
5853             {
5854               last = convert (bitsizetype, last);
5855               if (constructor_max_index != 0
5856                   && tree_int_cst_lt (constructor_max_index, last))
5857                 {
5858                   error_init ("array index range in initializer exceeds array bounds");
5859                   last = 0;
5860                 }
5861             }
5862         }
5863
5864       designator_depth++;
5865       designator_erroneous = 0;
5866       if (constructor_range_stack || last)
5867         push_range_stack (last);
5868     }
5869 }
5870
5871 /* Within a struct initializer, specify the next field to be initialized.  */
5872
5873 void
5874 set_init_label (tree fieldname)
5875 {
5876   tree tail;
5877
5878   if (set_designator (0))
5879     return;
5880
5881   designator_erroneous = 1;
5882
5883   if (TREE_CODE (constructor_type) != RECORD_TYPE
5884       && TREE_CODE (constructor_type) != UNION_TYPE)
5885     {
5886       error_init ("field name not in record or union initializer");
5887       return;
5888     }
5889
5890   for (tail = TYPE_FIELDS (constructor_type); tail;
5891        tail = TREE_CHAIN (tail))
5892     {
5893       if (DECL_NAME (tail) == fieldname)
5894         break;
5895     }
5896
5897   if (tail == 0)
5898     error ("unknown field %qE specified in initializer", fieldname);
5899   else
5900     {
5901       constructor_fields = tail;
5902       designator_depth++;
5903       designator_erroneous = 0;
5904       if (constructor_range_stack)
5905         push_range_stack (NULL_TREE);
5906     }
5907 }
5908 \f
5909 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5910    identifies the initializer, either array index or field in a structure.
5911    VALUE is the value of that index or field.  */
5912
5913 static void
5914 add_pending_init (tree purpose, tree value)
5915 {
5916   struct init_node *p, **q, *r;
5917
5918   q = &constructor_pending_elts;
5919   p = 0;
5920
5921   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5922     {
5923       while (*q != 0)
5924         {
5925           p = *q;
5926           if (tree_int_cst_lt (purpose, p->purpose))
5927             q = &p->left;
5928           else if (tree_int_cst_lt (p->purpose, purpose))
5929             q = &p->right;
5930           else
5931             {
5932               if (TREE_SIDE_EFFECTS (p->value))
5933                 warning_init (0, "initialized field with side-effects overwritten");
5934               else if (warn_override_init)
5935                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5936               p->value = value;
5937               return;
5938             }
5939         }
5940     }
5941   else
5942     {
5943       tree bitpos;
5944
5945       bitpos = bit_position (purpose);
5946       while (*q != NULL)
5947         {
5948           p = *q;
5949           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5950             q = &p->left;
5951           else if (p->purpose != purpose)
5952             q = &p->right;
5953           else
5954             {
5955               if (TREE_SIDE_EFFECTS (p->value))
5956                 warning_init (0, "initialized field with side-effects overwritten");
5957               else if (warn_override_init)
5958                 warning_init (OPT_Woverride_init, "initialized field overwritten");
5959               p->value = value;
5960               return;
5961             }
5962         }
5963     }
5964
5965   r = GGC_NEW (struct init_node);
5966   r->purpose = purpose;
5967   r->value = value;
5968
5969   *q = r;
5970   r->parent = p;
5971   r->left = 0;
5972   r->right = 0;
5973   r->balance = 0;
5974
5975   while (p)
5976     {
5977       struct init_node *s;
5978
5979       if (r == p->left)
5980         {
5981           if (p->balance == 0)
5982             p->balance = -1;
5983           else if (p->balance < 0)
5984             {
5985               if (r->balance < 0)
5986                 {
5987                   /* L rotation.  */
5988                   p->left = r->right;
5989                   if (p->left)
5990                     p->left->parent = p;
5991                   r->right = p;
5992
5993                   p->balance = 0;
5994                   r->balance = 0;
5995
5996                   s = p->parent;
5997                   p->parent = r;
5998                   r->parent = s;
5999                   if (s)
6000                     {
6001                       if (s->left == p)
6002                         s->left = r;
6003                       else
6004                         s->right = r;
6005                     }
6006                   else
6007                     constructor_pending_elts = r;
6008                 }
6009               else
6010                 {
6011                   /* LR rotation.  */
6012                   struct init_node *t = r->right;
6013
6014                   r->right = t->left;
6015                   if (r->right)
6016                     r->right->parent = r;
6017                   t->left = r;
6018
6019                   p->left = t->right;
6020                   if (p->left)
6021                     p->left->parent = p;
6022                   t->right = p;
6023
6024                   p->balance = t->balance < 0;
6025                   r->balance = -(t->balance > 0);
6026                   t->balance = 0;
6027
6028                   s = p->parent;
6029                   p->parent = t;
6030                   r->parent = t;
6031                   t->parent = s;
6032                   if (s)
6033                     {
6034                       if (s->left == p)
6035                         s->left = t;
6036                       else
6037                         s->right = t;
6038                     }
6039                   else
6040                     constructor_pending_elts = t;
6041                 }
6042               break;
6043             }
6044           else
6045             {
6046               /* p->balance == +1; growth of left side balances the node.  */
6047               p->balance = 0;
6048               break;
6049             }
6050         }
6051       else /* r == p->right */
6052         {
6053           if (p->balance == 0)
6054             /* Growth propagation from right side.  */
6055             p->balance++;
6056           else if (p->balance > 0)
6057             {
6058               if (r->balance > 0)
6059                 {
6060                   /* R rotation.  */
6061                   p->right = r->left;
6062                   if (p->right)
6063                     p->right->parent = p;
6064                   r->left = p;
6065
6066                   p->balance = 0;
6067                   r->balance = 0;
6068
6069                   s = p->parent;
6070                   p->parent = r;
6071                   r->parent = s;
6072                   if (s)
6073                     {
6074                       if (s->left == p)
6075                         s->left = r;
6076                       else
6077                         s->right = r;
6078                     }
6079                   else
6080                     constructor_pending_elts = r;
6081                 }
6082               else /* r->balance == -1 */
6083                 {
6084                   /* RL rotation */
6085                   struct init_node *t = r->left;
6086
6087                   r->left = t->right;
6088                   if (r->left)
6089                     r->left->parent = r;
6090                   t->right = r;
6091
6092                   p->right = t->left;
6093                   if (p->right)
6094                     p->right->parent = p;
6095                   t->left = p;
6096
6097                   r->balance = (t->balance < 0);
6098                   p->balance = -(t->balance > 0);
6099                   t->balance = 0;
6100
6101                   s = p->parent;
6102                   p->parent = t;
6103                   r->parent = t;
6104                   t->parent = s;
6105                   if (s)
6106                     {
6107                       if (s->left == p)
6108                         s->left = t;
6109                       else
6110                         s->right = t;
6111                     }
6112                   else
6113                     constructor_pending_elts = t;
6114                 }
6115               break;
6116             }
6117           else
6118             {
6119               /* p->balance == -1; growth of right side balances the node.  */
6120               p->balance = 0;
6121               break;
6122             }
6123         }
6124
6125       r = p;
6126       p = p->parent;
6127     }
6128 }
6129
6130 /* Build AVL tree from a sorted chain.  */
6131
6132 static void
6133 set_nonincremental_init (void)
6134 {
6135   unsigned HOST_WIDE_INT ix;
6136   tree index, value;
6137
6138   if (TREE_CODE (constructor_type) != RECORD_TYPE
6139       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6140     return;
6141
6142   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6143     add_pending_init (index, value);
6144   constructor_elements = 0;
6145   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6146     {
6147       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6148       /* Skip any nameless bit fields at the beginning.  */
6149       while (constructor_unfilled_fields != 0
6150              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6151              && DECL_NAME (constructor_unfilled_fields) == 0)
6152         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6153
6154     }
6155   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6156     {
6157       if (TYPE_DOMAIN (constructor_type))
6158         constructor_unfilled_index
6159             = convert (bitsizetype,
6160                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6161       else
6162         constructor_unfilled_index = bitsize_zero_node;
6163     }
6164   constructor_incremental = 0;
6165 }
6166
6167 /* Build AVL tree from a string constant.  */
6168
6169 static void
6170 set_nonincremental_init_from_string (tree str)
6171 {
6172   tree value, purpose, type;
6173   HOST_WIDE_INT val[2];
6174   const char *p, *end;
6175   int byte, wchar_bytes, charwidth, bitpos;
6176
6177   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6178
6179   wchar_bytes = TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str))) / BITS_PER_UNIT;
6180   charwidth = TYPE_PRECISION (char_type_node);
6181   type = TREE_TYPE (constructor_type);
6182   p = TREE_STRING_POINTER (str);
6183   end = p + TREE_STRING_LENGTH (str);
6184
6185   for (purpose = bitsize_zero_node;
6186        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6187        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6188     {
6189       if (wchar_bytes == 1)
6190         {
6191           val[1] = (unsigned char) *p++;
6192           val[0] = 0;
6193         }
6194       else
6195         {
6196           val[0] = 0;
6197           val[1] = 0;
6198           for (byte = 0; byte < wchar_bytes; byte++)
6199             {
6200               if (BYTES_BIG_ENDIAN)
6201                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6202               else
6203                 bitpos = byte * charwidth;
6204               val[bitpos < HOST_BITS_PER_WIDE_INT]
6205                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6206                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6207             }
6208         }
6209
6210       if (!TYPE_UNSIGNED (type))
6211         {
6212           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6213           if (bitpos < HOST_BITS_PER_WIDE_INT)
6214             {
6215               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6216                 {
6217                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6218                   val[0] = -1;
6219                 }
6220             }
6221           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6222             {
6223               if (val[1] < 0)
6224                 val[0] = -1;
6225             }
6226           else if (val[0] & (((HOST_WIDE_INT) 1)
6227                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6228             val[0] |= ((HOST_WIDE_INT) -1)
6229                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6230         }
6231
6232       value = build_int_cst_wide (type, val[1], val[0]);
6233       add_pending_init (purpose, value);
6234     }
6235
6236   constructor_incremental = 0;
6237 }
6238
6239 /* Return value of FIELD in pending initializer or zero if the field was
6240    not initialized yet.  */
6241
6242 static tree
6243 find_init_member (tree field)
6244 {
6245   struct init_node *p;
6246
6247   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6248     {
6249       if (constructor_incremental
6250           && tree_int_cst_lt (field, constructor_unfilled_index))
6251         set_nonincremental_init ();
6252
6253       p = constructor_pending_elts;
6254       while (p)
6255         {
6256           if (tree_int_cst_lt (field, p->purpose))
6257             p = p->left;
6258           else if (tree_int_cst_lt (p->purpose, field))
6259             p = p->right;
6260           else
6261             return p->value;
6262         }
6263     }
6264   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6265     {
6266       tree bitpos = bit_position (field);
6267
6268       if (constructor_incremental
6269           && (!constructor_unfilled_fields
6270               || tree_int_cst_lt (bitpos,
6271                                   bit_position (constructor_unfilled_fields))))
6272         set_nonincremental_init ();
6273
6274       p = constructor_pending_elts;
6275       while (p)
6276         {
6277           if (field == p->purpose)
6278             return p->value;
6279           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6280             p = p->left;
6281           else
6282             p = p->right;
6283         }
6284     }
6285   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6286     {
6287       if (!VEC_empty (constructor_elt, constructor_elements)
6288           && (VEC_last (constructor_elt, constructor_elements)->index
6289               == field))
6290         return VEC_last (constructor_elt, constructor_elements)->value;
6291     }
6292   return 0;
6293 }
6294
6295 /* "Output" the next constructor element.
6296    At top level, really output it to assembler code now.
6297    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6298    TYPE is the data type that the containing data type wants here.
6299    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6300    If VALUE is a string constant, STRICT_STRING is true if it is
6301    unparenthesized or we should not warn here for it being parenthesized.
6302    For other types of VALUE, STRICT_STRING is not used.
6303
6304    PENDING if non-nil means output pending elements that belong
6305    right after this element.  (PENDING is normally 1;
6306    it is 0 while outputting pending elements, to avoid recursion.)  */
6307
6308 static void
6309 output_init_element (tree value, bool strict_string, tree type, tree field,
6310                      int pending)
6311 {
6312   constructor_elt *celt;
6313
6314   if (type == error_mark_node || value == error_mark_node)
6315     {
6316       constructor_erroneous = 1;
6317       return;
6318     }
6319   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6320       && (TREE_CODE (value) == STRING_CST
6321           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6322       && !(TREE_CODE (value) == STRING_CST
6323            && TREE_CODE (type) == ARRAY_TYPE
6324            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6325       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6326                      TYPE_MAIN_VARIANT (type)))
6327     value = array_to_pointer_conversion (value);
6328
6329   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6330       && require_constant_value && !flag_isoc99 && pending)
6331     {
6332       /* As an extension, allow initializing objects with static storage
6333          duration with compound literals (which are then treated just as
6334          the brace enclosed list they contain).  */
6335       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6336       value = DECL_INITIAL (decl);
6337     }
6338
6339   if (value == error_mark_node)
6340     constructor_erroneous = 1;
6341   else if (!TREE_CONSTANT (value))
6342     constructor_constant = 0;
6343   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6344            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6345                 || TREE_CODE (constructor_type) == UNION_TYPE)
6346                && DECL_C_BIT_FIELD (field)
6347                && TREE_CODE (value) != INTEGER_CST))
6348     constructor_simple = 0;
6349
6350   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6351     {
6352       if (require_constant_value)
6353         {
6354           error_init ("initializer element is not constant");
6355           value = error_mark_node;
6356         }
6357       else if (require_constant_elements)
6358         pedwarn (input_location, 0,
6359                  "initializer element is not computable at load time");
6360     }
6361
6362   /* If this field is empty (and not at the end of structure),
6363      don't do anything other than checking the initializer.  */
6364   if (field
6365       && (TREE_TYPE (field) == error_mark_node
6366           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6367               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6368               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6369                   || TREE_CHAIN (field)))))
6370     return;
6371
6372   value = digest_init (type, value, strict_string, require_constant_value);
6373   if (value == error_mark_node)
6374     {
6375       constructor_erroneous = 1;
6376       return;
6377     }
6378
6379   /* If this element doesn't come next in sequence,
6380      put it on constructor_pending_elts.  */
6381   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6382       && (!constructor_incremental
6383           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6384     {
6385       if (constructor_incremental
6386           && tree_int_cst_lt (field, constructor_unfilled_index))
6387         set_nonincremental_init ();
6388
6389       add_pending_init (field, value);
6390       return;
6391     }
6392   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6393            && (!constructor_incremental
6394                || field != constructor_unfilled_fields))
6395     {
6396       /* We do this for records but not for unions.  In a union,
6397          no matter which field is specified, it can be initialized
6398          right away since it starts at the beginning of the union.  */
6399       if (constructor_incremental)
6400         {
6401           if (!constructor_unfilled_fields)
6402             set_nonincremental_init ();
6403           else
6404             {
6405               tree bitpos, unfillpos;
6406
6407               bitpos = bit_position (field);
6408               unfillpos = bit_position (constructor_unfilled_fields);
6409
6410               if (tree_int_cst_lt (bitpos, unfillpos))
6411                 set_nonincremental_init ();
6412             }
6413         }
6414
6415       add_pending_init (field, value);
6416       return;
6417     }
6418   else if (TREE_CODE (constructor_type) == UNION_TYPE
6419            && !VEC_empty (constructor_elt, constructor_elements))
6420     {
6421       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6422                                        constructor_elements)->value))
6423         warning_init (0, "initialized field with side-effects overwritten");
6424       else if (warn_override_init)
6425         warning_init (OPT_Woverride_init, "initialized field overwritten");
6426
6427       /* We can have just one union field set.  */
6428       constructor_elements = 0;
6429     }
6430
6431   /* Otherwise, output this element either to
6432      constructor_elements or to the assembler file.  */
6433
6434   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6435   celt->index = field;
6436   celt->value = value;
6437
6438   /* Advance the variable that indicates sequential elements output.  */
6439   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6440     constructor_unfilled_index
6441       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6442                     bitsize_one_node);
6443   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6444     {
6445       constructor_unfilled_fields
6446         = TREE_CHAIN (constructor_unfilled_fields);
6447
6448       /* Skip any nameless bit fields.  */
6449       while (constructor_unfilled_fields != 0
6450              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6451              && DECL_NAME (constructor_unfilled_fields) == 0)
6452         constructor_unfilled_fields =
6453           TREE_CHAIN (constructor_unfilled_fields);
6454     }
6455   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6456     constructor_unfilled_fields = 0;
6457
6458   /* Now output any pending elements which have become next.  */
6459   if (pending)
6460     output_pending_init_elements (0);
6461 }
6462
6463 /* Output any pending elements which have become next.
6464    As we output elements, constructor_unfilled_{fields,index}
6465    advances, which may cause other elements to become next;
6466    if so, they too are output.
6467
6468    If ALL is 0, we return when there are
6469    no more pending elements to output now.
6470
6471    If ALL is 1, we output space as necessary so that
6472    we can output all the pending elements.  */
6473
6474 static void
6475 output_pending_init_elements (int all)
6476 {
6477   struct init_node *elt = constructor_pending_elts;
6478   tree next;
6479
6480  retry:
6481
6482   /* Look through the whole pending tree.
6483      If we find an element that should be output now,
6484      output it.  Otherwise, set NEXT to the element
6485      that comes first among those still pending.  */
6486
6487   next = 0;
6488   while (elt)
6489     {
6490       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6491         {
6492           if (tree_int_cst_equal (elt->purpose,
6493                                   constructor_unfilled_index))
6494             output_init_element (elt->value, true,
6495                                  TREE_TYPE (constructor_type),
6496                                  constructor_unfilled_index, 0);
6497           else if (tree_int_cst_lt (constructor_unfilled_index,
6498                                     elt->purpose))
6499             {
6500               /* Advance to the next smaller node.  */
6501               if (elt->left)
6502                 elt = elt->left;
6503               else
6504                 {
6505                   /* We have reached the smallest node bigger than the
6506                      current unfilled index.  Fill the space first.  */
6507                   next = elt->purpose;
6508                   break;
6509                 }
6510             }
6511           else
6512             {
6513               /* Advance to the next bigger node.  */
6514               if (elt->right)
6515                 elt = elt->right;
6516               else
6517                 {
6518                   /* We have reached the biggest node in a subtree.  Find
6519                      the parent of it, which is the next bigger node.  */
6520                   while (elt->parent && elt->parent->right == elt)
6521                     elt = elt->parent;
6522                   elt = elt->parent;
6523                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6524                                               elt->purpose))
6525                     {
6526                       next = elt->purpose;
6527                       break;
6528                     }
6529                 }
6530             }
6531         }
6532       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6533                || TREE_CODE (constructor_type) == UNION_TYPE)
6534         {
6535           tree ctor_unfilled_bitpos, elt_bitpos;
6536
6537           /* If the current record is complete we are done.  */
6538           if (constructor_unfilled_fields == 0)
6539             break;
6540
6541           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6542           elt_bitpos = bit_position (elt->purpose);
6543           /* We can't compare fields here because there might be empty
6544              fields in between.  */
6545           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6546             {
6547               constructor_unfilled_fields = elt->purpose;
6548               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6549                                    elt->purpose, 0);
6550             }
6551           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6552             {
6553               /* Advance to the next smaller node.  */
6554               if (elt->left)
6555                 elt = elt->left;
6556               else
6557                 {
6558                   /* We have reached the smallest node bigger than the
6559                      current unfilled field.  Fill the space first.  */
6560                   next = elt->purpose;
6561                   break;
6562                 }
6563             }
6564           else
6565             {
6566               /* Advance to the next bigger node.  */
6567               if (elt->right)
6568                 elt = elt->right;
6569               else
6570                 {
6571                   /* We have reached the biggest node in a subtree.  Find
6572                      the parent of it, which is the next bigger node.  */
6573                   while (elt->parent && elt->parent->right == elt)
6574                     elt = elt->parent;
6575                   elt = elt->parent;
6576                   if (elt
6577                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6578                                            bit_position (elt->purpose))))
6579                     {
6580                       next = elt->purpose;
6581                       break;
6582                     }
6583                 }
6584             }
6585         }
6586     }
6587
6588   /* Ordinarily return, but not if we want to output all
6589      and there are elements left.  */
6590   if (!(all && next != 0))
6591     return;
6592
6593   /* If it's not incremental, just skip over the gap, so that after
6594      jumping to retry we will output the next successive element.  */
6595   if (TREE_CODE (constructor_type) == RECORD_TYPE
6596       || TREE_CODE (constructor_type) == UNION_TYPE)
6597     constructor_unfilled_fields = next;
6598   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6599     constructor_unfilled_index = next;
6600
6601   /* ELT now points to the node in the pending tree with the next
6602      initializer to output.  */
6603   goto retry;
6604 }
6605 \f
6606 /* Add one non-braced element to the current constructor level.
6607    This adjusts the current position within the constructor's type.
6608    This may also start or terminate implicit levels
6609    to handle a partly-braced initializer.
6610
6611    Once this has found the correct level for the new element,
6612    it calls output_init_element.  */
6613
6614 void
6615 process_init_element (struct c_expr value)
6616 {
6617   tree orig_value = value.value;
6618   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6619   bool strict_string = value.original_code == STRING_CST;
6620
6621   designator_depth = 0;
6622   designator_erroneous = 0;
6623
6624   /* Handle superfluous braces around string cst as in
6625      char x[] = {"foo"}; */
6626   if (string_flag
6627       && constructor_type
6628       && TREE_CODE (constructor_type) == ARRAY_TYPE
6629       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6630       && integer_zerop (constructor_unfilled_index))
6631     {
6632       if (constructor_stack->replacement_value.value)
6633         error_init ("excess elements in char array initializer");
6634       constructor_stack->replacement_value = value;
6635       return;
6636     }
6637
6638   if (constructor_stack->replacement_value.value != 0)
6639     {
6640       error_init ("excess elements in struct initializer");
6641       return;
6642     }
6643
6644   /* Ignore elements of a brace group if it is entirely superfluous
6645      and has already been diagnosed.  */
6646   if (constructor_type == 0)
6647     return;
6648
6649   /* If we've exhausted any levels that didn't have braces,
6650      pop them now.  */
6651   while (constructor_stack->implicit)
6652     {
6653       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6654            || TREE_CODE (constructor_type) == UNION_TYPE)
6655           && constructor_fields == 0)
6656         process_init_element (pop_init_level (1));
6657       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6658                && (constructor_max_index == 0
6659                    || tree_int_cst_lt (constructor_max_index,
6660                                        constructor_index)))
6661         process_init_element (pop_init_level (1));
6662       else
6663         break;
6664     }
6665
6666   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6667   if (constructor_range_stack)
6668     {
6669       /* If value is a compound literal and we'll be just using its
6670          content, don't put it into a SAVE_EXPR.  */
6671       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6672           || !require_constant_value
6673           || flag_isoc99)
6674         value.value = save_expr (value.value);
6675     }
6676
6677   while (1)
6678     {
6679       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6680         {
6681           tree fieldtype;
6682           enum tree_code fieldcode;
6683
6684           if (constructor_fields == 0)
6685             {
6686               pedwarn_init (input_location, 0,
6687                             "excess elements in struct initializer");
6688               break;
6689             }
6690
6691           fieldtype = TREE_TYPE (constructor_fields);
6692           if (fieldtype != error_mark_node)
6693             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6694           fieldcode = TREE_CODE (fieldtype);
6695
6696           /* Error for non-static initialization of a flexible array member.  */
6697           if (fieldcode == ARRAY_TYPE
6698               && !require_constant_value
6699               && TYPE_SIZE (fieldtype) == NULL_TREE
6700               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6701             {
6702               error_init ("non-static initialization of a flexible array member");
6703               break;
6704             }
6705
6706           /* Accept a string constant to initialize a subarray.  */
6707           if (value.value != 0
6708               && fieldcode == ARRAY_TYPE
6709               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6710               && string_flag)
6711             value.value = orig_value;
6712           /* Otherwise, if we have come to a subaggregate,
6713              and we don't have an element of its type, push into it.  */
6714           else if (value.value != 0
6715                    && value.value != error_mark_node
6716                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6717                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6718                        || fieldcode == UNION_TYPE))
6719             {
6720               push_init_level (1);
6721               continue;
6722             }
6723
6724           if (value.value)
6725             {
6726               push_member_name (constructor_fields);
6727               output_init_element (value.value, strict_string,
6728                                    fieldtype, constructor_fields, 1);
6729               RESTORE_SPELLING_DEPTH (constructor_depth);
6730             }
6731           else
6732             /* Do the bookkeeping for an element that was
6733                directly output as a constructor.  */
6734             {
6735               /* For a record, keep track of end position of last field.  */
6736               if (DECL_SIZE (constructor_fields))
6737                 constructor_bit_index
6738                   = size_binop (PLUS_EXPR,
6739                                 bit_position (constructor_fields),
6740                                 DECL_SIZE (constructor_fields));
6741
6742               /* If the current field was the first one not yet written out,
6743                  it isn't now, so update.  */
6744               if (constructor_unfilled_fields == constructor_fields)
6745                 {
6746                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6747                   /* Skip any nameless bit fields.  */
6748                   while (constructor_unfilled_fields != 0
6749                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6750                          && DECL_NAME (constructor_unfilled_fields) == 0)
6751                     constructor_unfilled_fields =
6752                       TREE_CHAIN (constructor_unfilled_fields);
6753                 }
6754             }
6755
6756           constructor_fields = TREE_CHAIN (constructor_fields);
6757           /* Skip any nameless bit fields at the beginning.  */
6758           while (constructor_fields != 0
6759                  && DECL_C_BIT_FIELD (constructor_fields)
6760                  && DECL_NAME (constructor_fields) == 0)
6761             constructor_fields = TREE_CHAIN (constructor_fields);
6762         }
6763       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6764         {
6765           tree fieldtype;
6766           enum tree_code fieldcode;
6767
6768           if (constructor_fields == 0)
6769             {
6770               pedwarn_init (input_location, 0,
6771                             "excess elements in union initializer");
6772               break;
6773             }
6774
6775           fieldtype = TREE_TYPE (constructor_fields);
6776           if (fieldtype != error_mark_node)
6777             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6778           fieldcode = TREE_CODE (fieldtype);
6779
6780           /* Warn that traditional C rejects initialization of unions.
6781              We skip the warning if the value is zero.  This is done
6782              under the assumption that the zero initializer in user
6783              code appears conditioned on e.g. __STDC__ to avoid
6784              "missing initializer" warnings and relies on default
6785              initialization to zero in the traditional C case.
6786              We also skip the warning if the initializer is designated,
6787              again on the assumption that this must be conditional on
6788              __STDC__ anyway (and we've already complained about the
6789              member-designator already).  */
6790           if (!in_system_header && !constructor_designated
6791               && !(value.value && (integer_zerop (value.value)
6792                                    || real_zerop (value.value))))
6793             warning (OPT_Wtraditional, "traditional C rejects initialization "
6794                      "of unions");
6795
6796           /* Accept a string constant to initialize a subarray.  */
6797           if (value.value != 0
6798               && fieldcode == ARRAY_TYPE
6799               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6800               && string_flag)
6801             value.value = orig_value;
6802           /* Otherwise, if we have come to a subaggregate,
6803              and we don't have an element of its type, push into it.  */
6804           else if (value.value != 0
6805                    && value.value != error_mark_node
6806                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6807                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6808                        || fieldcode == UNION_TYPE))
6809             {
6810               push_init_level (1);
6811               continue;
6812             }
6813
6814           if (value.value)
6815             {
6816               push_member_name (constructor_fields);
6817               output_init_element (value.value, strict_string,
6818                                    fieldtype, constructor_fields, 1);
6819               RESTORE_SPELLING_DEPTH (constructor_depth);
6820             }
6821           else
6822             /* Do the bookkeeping for an element that was
6823                directly output as a constructor.  */
6824             {
6825               constructor_bit_index = DECL_SIZE (constructor_fields);
6826               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6827             }
6828
6829           constructor_fields = 0;
6830         }
6831       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6832         {
6833           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6834           enum tree_code eltcode = TREE_CODE (elttype);
6835
6836           /* Accept a string constant to initialize a subarray.  */
6837           if (value.value != 0
6838               && eltcode == ARRAY_TYPE
6839               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6840               && string_flag)
6841             value.value = orig_value;
6842           /* Otherwise, if we have come to a subaggregate,
6843              and we don't have an element of its type, push into it.  */
6844           else if (value.value != 0
6845                    && value.value != error_mark_node
6846                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6847                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6848                        || eltcode == UNION_TYPE))
6849             {
6850               push_init_level (1);
6851               continue;
6852             }
6853
6854           if (constructor_max_index != 0
6855               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6856                   || integer_all_onesp (constructor_max_index)))
6857             {
6858               pedwarn_init (input_location, 0,
6859                             "excess elements in array initializer");
6860               break;
6861             }
6862
6863           /* Now output the actual element.  */
6864           if (value.value)
6865             {
6866               push_array_bounds (tree_low_cst (constructor_index, 1));
6867               output_init_element (value.value, strict_string,
6868                                    elttype, constructor_index, 1);
6869               RESTORE_SPELLING_DEPTH (constructor_depth);
6870             }
6871
6872           constructor_index
6873             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6874
6875           if (!value.value)
6876             /* If we are doing the bookkeeping for an element that was
6877                directly output as a constructor, we must update
6878                constructor_unfilled_index.  */
6879             constructor_unfilled_index = constructor_index;
6880         }
6881       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6882         {
6883           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6884
6885          /* Do a basic check of initializer size.  Note that vectors
6886             always have a fixed size derived from their type.  */
6887           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6888             {
6889               pedwarn_init (input_location, 0,
6890                             "excess elements in vector initializer");
6891               break;
6892             }
6893
6894           /* Now output the actual element.  */
6895           if (value.value)
6896             output_init_element (value.value, strict_string,
6897                                  elttype, constructor_index, 1);
6898
6899           constructor_index
6900             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6901
6902           if (!value.value)
6903             /* If we are doing the bookkeeping for an element that was
6904                directly output as a constructor, we must update
6905                constructor_unfilled_index.  */
6906             constructor_unfilled_index = constructor_index;
6907         }
6908
6909       /* Handle the sole element allowed in a braced initializer
6910          for a scalar variable.  */
6911       else if (constructor_type != error_mark_node
6912                && constructor_fields == 0)
6913         {
6914           pedwarn_init (input_location, 0,
6915                         "excess elements in scalar initializer");
6916           break;
6917         }
6918       else
6919         {
6920           if (value.value)
6921             output_init_element (value.value, strict_string,
6922                                  constructor_type, NULL_TREE, 1);
6923           constructor_fields = 0;
6924         }
6925
6926       /* Handle range initializers either at this level or anywhere higher
6927          in the designator stack.  */
6928       if (constructor_range_stack)
6929         {
6930           struct constructor_range_stack *p, *range_stack;
6931           int finish = 0;
6932
6933           range_stack = constructor_range_stack;
6934           constructor_range_stack = 0;
6935           while (constructor_stack != range_stack->stack)
6936             {
6937               gcc_assert (constructor_stack->implicit);
6938               process_init_element (pop_init_level (1));
6939             }
6940           for (p = range_stack;
6941                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6942                p = p->prev)
6943             {
6944               gcc_assert (constructor_stack->implicit);
6945               process_init_element (pop_init_level (1));
6946             }
6947
6948           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6949           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6950             finish = 1;
6951
6952           while (1)
6953             {
6954               constructor_index = p->index;
6955               constructor_fields = p->fields;
6956               if (finish && p->range_end && p->index == p->range_start)
6957                 {
6958                   finish = 0;
6959                   p->prev = 0;
6960                 }
6961               p = p->next;
6962               if (!p)
6963                 break;
6964               push_init_level (2);
6965               p->stack = constructor_stack;
6966               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6967                 p->index = p->range_start;
6968             }
6969
6970           if (!finish)
6971             constructor_range_stack = range_stack;
6972           continue;
6973         }
6974
6975       break;
6976     }
6977
6978   constructor_range_stack = 0;
6979 }
6980 \f
6981 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6982    (guaranteed to be 'volatile' or null) and ARGS (represented using
6983    an ASM_EXPR node).  */
6984 tree
6985 build_asm_stmt (tree cv_qualifier, tree args)
6986 {
6987   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6988     ASM_VOLATILE_P (args) = 1;
6989   return add_stmt (args);
6990 }
6991
6992 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6993    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6994    SIMPLE indicates whether there was anything at all after the
6995    string in the asm expression -- asm("blah") and asm("blah" : )
6996    are subtly different.  We use a ASM_EXPR node to represent this.  */
6997 tree
6998 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6999                 bool simple)
7000 {
7001   tree tail;
7002   tree args;
7003   int i;
7004   const char *constraint;
7005   const char **oconstraints;
7006   bool allows_mem, allows_reg, is_inout;
7007   int ninputs, noutputs;
7008
7009   ninputs = list_length (inputs);
7010   noutputs = list_length (outputs);
7011   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
7012
7013   string = resolve_asm_operand_names (string, outputs, inputs);
7014
7015   /* Remove output conversions that change the type but not the mode.  */
7016   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
7017     {
7018       tree output = TREE_VALUE (tail);
7019
7020       /* ??? Really, this should not be here.  Users should be using a
7021          proper lvalue, dammit.  But there's a long history of using casts
7022          in the output operands.  In cases like longlong.h, this becomes a
7023          primitive form of typechecking -- if the cast can be removed, then
7024          the output operand had a type of the proper width; otherwise we'll
7025          get an error.  Gross, but ...  */
7026       STRIP_NOPS (output);
7027
7028       if (!lvalue_or_else (output, lv_asm))
7029         output = error_mark_node;
7030
7031       if (output != error_mark_node
7032           && (TREE_READONLY (output)
7033               || TYPE_READONLY (TREE_TYPE (output))
7034               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
7035                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
7036                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
7037         readonly_error (output, lv_asm);
7038
7039       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7040       oconstraints[i] = constraint;
7041
7042       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
7043                                    &allows_mem, &allows_reg, &is_inout))
7044         {
7045           /* If the operand is going to end up in memory,
7046              mark it addressable.  */
7047           if (!allows_reg && !c_mark_addressable (output))
7048             output = error_mark_node;
7049         }
7050       else
7051         output = error_mark_node;
7052
7053       TREE_VALUE (tail) = output;
7054     }
7055
7056   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
7057     {
7058       tree input;
7059
7060       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
7061       input = TREE_VALUE (tail);
7062
7063       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
7064                                   oconstraints, &allows_mem, &allows_reg))
7065         {
7066           /* If the operand is going to end up in memory,
7067              mark it addressable.  */
7068           if (!allows_reg && allows_mem)
7069             {
7070               /* Strip the nops as we allow this case.  FIXME, this really
7071                  should be rejected or made deprecated.  */
7072               STRIP_NOPS (input);
7073               if (!c_mark_addressable (input))
7074                 input = error_mark_node;
7075           }
7076         }
7077       else
7078         input = error_mark_node;
7079
7080       TREE_VALUE (tail) = input;
7081     }
7082
7083   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
7084
7085   /* asm statements without outputs, including simple ones, are treated
7086      as volatile.  */
7087   ASM_INPUT_P (args) = simple;
7088   ASM_VOLATILE_P (args) = (noutputs == 0);
7089
7090   return args;
7091 }
7092 \f
7093 /* Generate a goto statement to LABEL.  */
7094
7095 tree
7096 c_finish_goto_label (tree label)
7097 {
7098   tree decl = lookup_label (label);
7099   if (!decl)
7100     return NULL_TREE;
7101
7102   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
7103     {
7104       error ("jump into statement expression");
7105       return NULL_TREE;
7106     }
7107
7108   if (C_DECL_UNJUMPABLE_VM (decl))
7109     {
7110       error ("jump into scope of identifier with variably modified type");
7111       return NULL_TREE;
7112     }
7113
7114   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7115     {
7116       /* No jump from outside this statement expression context, so
7117          record that there is a jump from within this context.  */
7118       struct c_label_list *nlist;
7119       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7120       nlist->next = label_context_stack_se->labels_used;
7121       nlist->label = decl;
7122       label_context_stack_se->labels_used = nlist;
7123     }
7124
7125   if (!C_DECL_UNDEFINABLE_VM (decl))
7126     {
7127       /* No jump from outside this context context of identifiers with
7128          variably modified type, so record that there is a jump from
7129          within this context.  */
7130       struct c_label_list *nlist;
7131       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7132       nlist->next = label_context_stack_vm->labels_used;
7133       nlist->label = decl;
7134       label_context_stack_vm->labels_used = nlist;
7135     }
7136
7137   TREE_USED (decl) = 1;
7138   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7139 }
7140
7141 /* Generate a computed goto statement to EXPR.  */
7142
7143 tree
7144 c_finish_goto_ptr (tree expr)
7145 {
7146   pedwarn (input_location, OPT_pedantic, "ISO C forbids %<goto *expr;%>");
7147   expr = convert (ptr_type_node, expr);
7148   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7149 }
7150
7151 /* Generate a C `return' statement.  RETVAL is the expression for what
7152    to return, or a null pointer for `return;' with no value.  */
7153
7154 tree
7155 c_finish_return (tree retval)
7156 {
7157   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7158   bool no_warning = false;
7159
7160   if (TREE_THIS_VOLATILE (current_function_decl))
7161     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7162
7163   if (!retval)
7164     {
7165       current_function_returns_null = 1;
7166       if ((warn_return_type || flag_isoc99)
7167           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7168         {
7169           pedwarn_c99 (input_location, flag_isoc99 ? 0 : OPT_Wreturn_type,
7170                        "%<return%> with no value, in "
7171                        "function returning non-void");
7172           no_warning = true;
7173         }
7174     }
7175   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7176     {
7177       current_function_returns_null = 1;
7178       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7179         pedwarn (input_location, 0,
7180                  "%<return%> with a value, in function returning void");
7181       else
7182         pedwarn (input_location, OPT_pedantic, "ISO C forbids "
7183                  "%<return%> with expression, in function returning void");
7184     }
7185   else
7186     {
7187       tree t = convert_for_assignment (valtype, retval, ic_return,
7188                                        NULL_TREE, NULL_TREE, 0);
7189       tree res = DECL_RESULT (current_function_decl);
7190       tree inner;
7191
7192       current_function_returns_value = 1;
7193       if (t == error_mark_node)
7194         return NULL_TREE;
7195
7196       inner = t = convert (TREE_TYPE (res), t);
7197
7198       /* Strip any conversions, additions, and subtractions, and see if
7199          we are returning the address of a local variable.  Warn if so.  */
7200       while (1)
7201         {
7202           switch (TREE_CODE (inner))
7203             {
7204             CASE_CONVERT:   case NON_LVALUE_EXPR:
7205             case PLUS_EXPR:
7206               inner = TREE_OPERAND (inner, 0);
7207               continue;
7208
7209             case MINUS_EXPR:
7210               /* If the second operand of the MINUS_EXPR has a pointer
7211                  type (or is converted from it), this may be valid, so
7212                  don't give a warning.  */
7213               {
7214                 tree op1 = TREE_OPERAND (inner, 1);
7215
7216                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7217                        && (CONVERT_EXPR_P (op1)
7218                            || TREE_CODE (op1) == NON_LVALUE_EXPR))
7219                   op1 = TREE_OPERAND (op1, 0);
7220
7221                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7222                   break;
7223
7224                 inner = TREE_OPERAND (inner, 0);
7225                 continue;
7226               }
7227
7228             case ADDR_EXPR:
7229               inner = TREE_OPERAND (inner, 0);
7230
7231               while (REFERENCE_CLASS_P (inner)
7232                      && TREE_CODE (inner) != INDIRECT_REF)
7233                 inner = TREE_OPERAND (inner, 0);
7234
7235               if (DECL_P (inner)
7236                   && !DECL_EXTERNAL (inner)
7237                   && !TREE_STATIC (inner)
7238                   && DECL_CONTEXT (inner) == current_function_decl)
7239                 warning (0, "function returns address of local variable");
7240               break;
7241
7242             default:
7243               break;
7244             }
7245
7246           break;
7247         }
7248
7249       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7250
7251       if (warn_sequence_point)
7252         verify_sequence_points (retval);
7253     }
7254
7255   ret_stmt = build_stmt (RETURN_EXPR, retval);
7256   TREE_NO_WARNING (ret_stmt) |= no_warning;
7257   return add_stmt (ret_stmt);
7258 }
7259 \f
7260 struct c_switch {
7261   /* The SWITCH_EXPR being built.  */
7262   tree switch_expr;
7263
7264   /* The original type of the testing expression, i.e. before the
7265      default conversion is applied.  */
7266   tree orig_type;
7267
7268   /* A splay-tree mapping the low element of a case range to the high
7269      element, or NULL_TREE if there is no high element.  Used to
7270      determine whether or not a new case label duplicates an old case
7271      label.  We need a tree, rather than simply a hash table, because
7272      of the GNU case range extension.  */
7273   splay_tree cases;
7274
7275   /* Number of nested statement expressions within this switch
7276      statement; if nonzero, case and default labels may not
7277      appear.  */
7278   unsigned int blocked_stmt_expr;
7279
7280   /* Scope of outermost declarations of identifiers with variably
7281      modified type within this switch statement; if nonzero, case and
7282      default labels may not appear.  */
7283   unsigned int blocked_vm;
7284
7285   /* The next node on the stack.  */
7286   struct c_switch *next;
7287 };
7288
7289 /* A stack of the currently active switch statements.  The innermost
7290    switch statement is on the top of the stack.  There is no need to
7291    mark the stack for garbage collection because it is only active
7292    during the processing of the body of a function, and we never
7293    collect at that point.  */
7294
7295 struct c_switch *c_switch_stack;
7296
7297 /* Start a C switch statement, testing expression EXP.  Return the new
7298    SWITCH_EXPR.  */
7299
7300 tree
7301 c_start_case (tree exp)
7302 {
7303   tree orig_type = error_mark_node;
7304   struct c_switch *cs;
7305
7306   if (exp != error_mark_node)
7307     {
7308       orig_type = TREE_TYPE (exp);
7309
7310       if (!INTEGRAL_TYPE_P (orig_type))
7311         {
7312           if (orig_type != error_mark_node)
7313             {
7314               error ("switch quantity not an integer");
7315               orig_type = error_mark_node;
7316             }
7317           exp = integer_zero_node;
7318         }
7319       else
7320         {
7321           tree type = TYPE_MAIN_VARIANT (orig_type);
7322
7323           if (!in_system_header
7324               && (type == long_integer_type_node
7325                   || type == long_unsigned_type_node))
7326             warning (OPT_Wtraditional, "%<long%> switch expression not "
7327                      "converted to %<int%> in ISO C");
7328
7329           exp = default_conversion (exp);
7330
7331           if (warn_sequence_point)
7332             verify_sequence_points (exp);
7333         }
7334     }
7335
7336   /* Add this new SWITCH_EXPR to the stack.  */
7337   cs = XNEW (struct c_switch);
7338   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7339   cs->orig_type = orig_type;
7340   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7341   cs->blocked_stmt_expr = 0;
7342   cs->blocked_vm = 0;
7343   cs->next = c_switch_stack;
7344   c_switch_stack = cs;
7345
7346   return add_stmt (cs->switch_expr);
7347 }
7348
7349 /* Process a case label.  */
7350
7351 tree
7352 do_case (tree low_value, tree high_value)
7353 {
7354   tree label = NULL_TREE;
7355
7356   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7357       && !c_switch_stack->blocked_vm)
7358     {
7359       label = c_add_case_label (c_switch_stack->cases,
7360                                 SWITCH_COND (c_switch_stack->switch_expr),
7361                                 c_switch_stack->orig_type,
7362                                 low_value, high_value);
7363       if (label == error_mark_node)
7364         label = NULL_TREE;
7365     }
7366   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7367     {
7368       if (low_value)
7369         error ("case label in statement expression not containing "
7370                "enclosing switch statement");
7371       else
7372         error ("%<default%> label in statement expression not containing "
7373                "enclosing switch statement");
7374     }
7375   else if (c_switch_stack && c_switch_stack->blocked_vm)
7376     {
7377       if (low_value)
7378         error ("case label in scope of identifier with variably modified "
7379                "type not containing enclosing switch statement");
7380       else
7381         error ("%<default%> label in scope of identifier with variably "
7382                "modified type not containing enclosing switch statement");
7383     }
7384   else if (low_value)
7385     error ("case label not within a switch statement");
7386   else
7387     error ("%<default%> label not within a switch statement");
7388
7389   return label;
7390 }
7391
7392 /* Finish the switch statement.  */
7393
7394 void
7395 c_finish_case (tree body)
7396 {
7397   struct c_switch *cs = c_switch_stack;
7398   location_t switch_location;
7399
7400   SWITCH_BODY (cs->switch_expr) = body;
7401
7402   /* We must not be within a statement expression nested in the switch
7403      at this point; we might, however, be within the scope of an
7404      identifier with variably modified type nested in the switch.  */
7405   gcc_assert (!cs->blocked_stmt_expr);
7406
7407   /* Emit warnings as needed.  */
7408   if (EXPR_HAS_LOCATION (cs->switch_expr))
7409     switch_location = EXPR_LOCATION (cs->switch_expr);
7410   else
7411     switch_location = input_location;
7412   c_do_switch_warnings (cs->cases, switch_location,
7413                         TREE_TYPE (cs->switch_expr),
7414                         SWITCH_COND (cs->switch_expr));
7415
7416   /* Pop the stack.  */
7417   c_switch_stack = cs->next;
7418   splay_tree_delete (cs->cases);
7419   XDELETE (cs);
7420 }
7421 \f
7422 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7423    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7424    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7425    statement, and was not surrounded with parenthesis.  */
7426
7427 void
7428 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7429                   tree else_block, bool nested_if)
7430 {
7431   tree stmt;
7432
7433   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7434   if (warn_parentheses && nested_if && else_block == NULL)
7435     {
7436       tree inner_if = then_block;
7437
7438       /* We know from the grammar productions that there is an IF nested
7439          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7440          it might not be exactly THEN_BLOCK, but should be the last
7441          non-container statement within.  */
7442       while (1)
7443         switch (TREE_CODE (inner_if))
7444           {
7445           case COND_EXPR:
7446             goto found;
7447           case BIND_EXPR:
7448             inner_if = BIND_EXPR_BODY (inner_if);
7449             break;
7450           case STATEMENT_LIST:
7451             inner_if = expr_last (then_block);
7452             break;
7453           case TRY_FINALLY_EXPR:
7454           case TRY_CATCH_EXPR:
7455             inner_if = TREE_OPERAND (inner_if, 0);
7456             break;
7457           default:
7458             gcc_unreachable ();
7459           }
7460     found:
7461
7462       if (COND_EXPR_ELSE (inner_if))
7463          warning (OPT_Wparentheses,
7464                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7465                   &if_locus);
7466     }
7467
7468   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7469   SET_EXPR_LOCATION (stmt, if_locus);
7470   add_stmt (stmt);
7471 }
7472
7473 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7474    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7475    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7476    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7477    the continue label.  Everything is allowed to be NULL.  */
7478
7479 void
7480 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7481                tree blab, tree clab, bool cond_is_first)
7482 {
7483   tree entry = NULL, exit = NULL, t;
7484
7485   /* If the condition is zero don't generate a loop construct.  */
7486   if (cond && integer_zerop (cond))
7487     {
7488       if (cond_is_first)
7489         {
7490           t = build_and_jump (&blab);
7491           SET_EXPR_LOCATION (t, start_locus);
7492           add_stmt (t);
7493         }
7494     }
7495   else
7496     {
7497       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7498
7499       /* If we have an exit condition, then we build an IF with gotos either
7500          out of the loop, or to the top of it.  If there's no exit condition,
7501          then we just build a jump back to the top.  */
7502       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7503
7504       if (cond && !integer_nonzerop (cond))
7505         {
7506           /* Canonicalize the loop condition to the end.  This means
7507              generating a branch to the loop condition.  Reuse the
7508              continue label, if possible.  */
7509           if (cond_is_first)
7510             {
7511               if (incr || !clab)
7512                 {
7513                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7514                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7515                 }
7516               else
7517                 t = build1 (GOTO_EXPR, void_type_node, clab);
7518               SET_EXPR_LOCATION (t, start_locus);
7519               add_stmt (t);
7520             }
7521
7522           t = build_and_jump (&blab);
7523           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7524           if (cond_is_first)
7525             SET_EXPR_LOCATION (exit, start_locus);
7526           else
7527             SET_EXPR_LOCATION (exit, input_location);
7528         }
7529
7530       add_stmt (top);
7531     }
7532
7533   if (body)
7534     add_stmt (body);
7535   if (clab)
7536     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7537   if (incr)
7538     add_stmt (incr);
7539   if (entry)
7540     add_stmt (entry);
7541   if (exit)
7542     add_stmt (exit);
7543   if (blab)
7544     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7545 }
7546
7547 tree
7548 c_finish_bc_stmt (tree *label_p, bool is_break)
7549 {
7550   bool skip;
7551   tree label = *label_p;
7552
7553   /* In switch statements break is sometimes stylistically used after
7554      a return statement.  This can lead to spurious warnings about
7555      control reaching the end of a non-void function when it is
7556      inlined.  Note that we are calling block_may_fallthru with
7557      language specific tree nodes; this works because
7558      block_may_fallthru returns true when given something it does not
7559      understand.  */
7560   skip = !block_may_fallthru (cur_stmt_list);
7561
7562   if (!label)
7563     {
7564       if (!skip)
7565         *label_p = label = create_artificial_label ();
7566     }
7567   else if (TREE_CODE (label) == LABEL_DECL)
7568     ;
7569   else switch (TREE_INT_CST_LOW (label))
7570     {
7571     case 0:
7572       if (is_break)
7573         error ("break statement not within loop or switch");
7574       else
7575         error ("continue statement not within a loop");
7576       return NULL_TREE;
7577
7578     case 1:
7579       gcc_assert (is_break);
7580       error ("break statement used with OpenMP for loop");
7581       return NULL_TREE;
7582
7583     default:
7584       gcc_unreachable ();
7585     }
7586
7587   if (skip)
7588     return NULL_TREE;
7589
7590   if (!is_break)
7591     add_stmt (build_predict_expr (PRED_CONTINUE, NOT_TAKEN));
7592
7593   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7594 }
7595
7596 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7597
7598 static void
7599 emit_side_effect_warnings (tree expr)
7600 {
7601   if (expr == error_mark_node)
7602     ;
7603   else if (!TREE_SIDE_EFFECTS (expr))
7604     {
7605       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7606         warning (OPT_Wunused_value, "%Hstatement with no effect",
7607                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7608     }
7609   else
7610     warn_if_unused_value (expr, input_location);
7611 }
7612
7613 /* Process an expression as if it were a complete statement.  Emit
7614    diagnostics, but do not call ADD_STMT.  */
7615
7616 tree
7617 c_process_expr_stmt (tree expr)
7618 {
7619   if (!expr)
7620     return NULL_TREE;
7621
7622   if (warn_sequence_point)
7623     verify_sequence_points (expr);
7624
7625   if (TREE_TYPE (expr) != error_mark_node
7626       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7627       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7628     error ("expression statement has incomplete type");
7629
7630   /* If we're not processing a statement expression, warn about unused values.
7631      Warnings for statement expressions will be emitted later, once we figure
7632      out which is the result.  */
7633   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7634       && warn_unused_value)
7635     emit_side_effect_warnings (expr);
7636
7637   /* If the expression is not of a type to which we cannot assign a line
7638      number, wrap the thing in a no-op NOP_EXPR.  */
7639   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7640     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7641
7642   if (CAN_HAVE_LOCATION_P (expr))
7643     SET_EXPR_LOCATION (expr, input_location);
7644
7645   return expr;
7646 }
7647
7648 /* Emit an expression as a statement.  */
7649
7650 tree
7651 c_finish_expr_stmt (tree expr)
7652 {
7653   if (expr)
7654     return add_stmt (c_process_expr_stmt (expr));
7655   else
7656     return NULL;
7657 }
7658
7659 /* Do the opposite and emit a statement as an expression.  To begin,
7660    create a new binding level and return it.  */
7661
7662 tree
7663 c_begin_stmt_expr (void)
7664 {
7665   tree ret;
7666   struct c_label_context_se *nstack;
7667   struct c_label_list *glist;
7668
7669   /* We must force a BLOCK for this level so that, if it is not expanded
7670      later, there is a way to turn off the entire subtree of blocks that
7671      are contained in it.  */
7672   keep_next_level ();
7673   ret = c_begin_compound_stmt (true);
7674   if (c_switch_stack)
7675     {
7676       c_switch_stack->blocked_stmt_expr++;
7677       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7678     }
7679   for (glist = label_context_stack_se->labels_used;
7680        glist != NULL;
7681        glist = glist->next)
7682     {
7683       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7684     }
7685   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7686   nstack->labels_def = NULL;
7687   nstack->labels_used = NULL;
7688   nstack->next = label_context_stack_se;
7689   label_context_stack_se = nstack;
7690
7691   /* Mark the current statement list as belonging to a statement list.  */
7692   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7693
7694   return ret;
7695 }
7696
7697 tree
7698 c_finish_stmt_expr (tree body)
7699 {
7700   tree last, type, tmp, val;
7701   tree *last_p;
7702   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7703
7704   body = c_end_compound_stmt (body, true);
7705   if (c_switch_stack)
7706     {
7707       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7708       c_switch_stack->blocked_stmt_expr--;
7709     }
7710   /* It is no longer possible to jump to labels defined within this
7711      statement expression.  */
7712   for (dlist = label_context_stack_se->labels_def;
7713        dlist != NULL;
7714        dlist = dlist->next)
7715     {
7716       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7717     }
7718   /* It is again possible to define labels with a goto just outside
7719      this statement expression.  */
7720   for (glist = label_context_stack_se->next->labels_used;
7721        glist != NULL;
7722        glist = glist->next)
7723     {
7724       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7725       glist_prev = glist;
7726     }
7727   if (glist_prev != NULL)
7728     glist_prev->next = label_context_stack_se->labels_used;
7729   else
7730     label_context_stack_se->next->labels_used
7731       = label_context_stack_se->labels_used;
7732   label_context_stack_se = label_context_stack_se->next;
7733
7734   /* Locate the last statement in BODY.  See c_end_compound_stmt
7735      about always returning a BIND_EXPR.  */
7736   last_p = &BIND_EXPR_BODY (body);
7737   last = BIND_EXPR_BODY (body);
7738
7739  continue_searching:
7740   if (TREE_CODE (last) == STATEMENT_LIST)
7741     {
7742       tree_stmt_iterator i;
7743
7744       /* This can happen with degenerate cases like ({ }).  No value.  */
7745       if (!TREE_SIDE_EFFECTS (last))
7746         return body;
7747
7748       /* If we're supposed to generate side effects warnings, process
7749          all of the statements except the last.  */
7750       if (warn_unused_value)
7751         {
7752           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7753             emit_side_effect_warnings (tsi_stmt (i));
7754         }
7755       else
7756         i = tsi_last (last);
7757       last_p = tsi_stmt_ptr (i);
7758       last = *last_p;
7759     }
7760
7761   /* If the end of the list is exception related, then the list was split
7762      by a call to push_cleanup.  Continue searching.  */
7763   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7764       || TREE_CODE (last) == TRY_CATCH_EXPR)
7765     {
7766       last_p = &TREE_OPERAND (last, 0);
7767       last = *last_p;
7768       goto continue_searching;
7769     }
7770
7771   /* In the case that the BIND_EXPR is not necessary, return the
7772      expression out from inside it.  */
7773   if (last == error_mark_node
7774       || (last == BIND_EXPR_BODY (body)
7775           && BIND_EXPR_VARS (body) == NULL))
7776     {
7777       /* Do not warn if the return value of a statement expression is
7778          unused.  */
7779       if (CAN_HAVE_LOCATION_P (last))
7780         TREE_NO_WARNING (last) = 1;
7781       return last;
7782     }
7783
7784   /* Extract the type of said expression.  */
7785   type = TREE_TYPE (last);
7786
7787   /* If we're not returning a value at all, then the BIND_EXPR that
7788      we already have is a fine expression to return.  */
7789   if (!type || VOID_TYPE_P (type))
7790     return body;
7791
7792   /* Now that we've located the expression containing the value, it seems
7793      silly to make voidify_wrapper_expr repeat the process.  Create a
7794      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7795   tmp = create_tmp_var_raw (type, NULL);
7796
7797   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7798      tree_expr_nonnegative_p giving up immediately.  */
7799   val = last;
7800   if (TREE_CODE (val) == NOP_EXPR
7801       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7802     val = TREE_OPERAND (val, 0);
7803
7804   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7805   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7806
7807   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7808 }
7809
7810 /* Begin the scope of an identifier of variably modified type, scope
7811    number SCOPE.  Jumping from outside this scope to inside it is not
7812    permitted.  */
7813
7814 void
7815 c_begin_vm_scope (unsigned int scope)
7816 {
7817   struct c_label_context_vm *nstack;
7818   struct c_label_list *glist;
7819
7820   gcc_assert (scope > 0);
7821
7822   /* At file_scope, we don't have to do any processing.  */
7823   if (label_context_stack_vm == NULL)
7824     return;
7825
7826   if (c_switch_stack && !c_switch_stack->blocked_vm)
7827     c_switch_stack->blocked_vm = scope;
7828   for (glist = label_context_stack_vm->labels_used;
7829        glist != NULL;
7830        glist = glist->next)
7831     {
7832       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7833     }
7834   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7835   nstack->labels_def = NULL;
7836   nstack->labels_used = NULL;
7837   nstack->scope = scope;
7838   nstack->next = label_context_stack_vm;
7839   label_context_stack_vm = nstack;
7840 }
7841
7842 /* End a scope which may contain identifiers of variably modified
7843    type, scope number SCOPE.  */
7844
7845 void
7846 c_end_vm_scope (unsigned int scope)
7847 {
7848   if (label_context_stack_vm == NULL)
7849     return;
7850   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7851     c_switch_stack->blocked_vm = 0;
7852   /* We may have a number of nested scopes of identifiers with
7853      variably modified type, all at this depth.  Pop each in turn.  */
7854   while (label_context_stack_vm->scope == scope)
7855     {
7856       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7857
7858       /* It is no longer possible to jump to labels defined within this
7859          scope.  */
7860       for (dlist = label_context_stack_vm->labels_def;
7861            dlist != NULL;
7862            dlist = dlist->next)
7863         {
7864           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7865         }
7866       /* It is again possible to define labels with a goto just outside
7867          this scope.  */
7868       for (glist = label_context_stack_vm->next->labels_used;
7869            glist != NULL;
7870            glist = glist->next)
7871         {
7872           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7873           glist_prev = glist;
7874         }
7875       if (glist_prev != NULL)
7876         glist_prev->next = label_context_stack_vm->labels_used;
7877       else
7878         label_context_stack_vm->next->labels_used
7879           = label_context_stack_vm->labels_used;
7880       label_context_stack_vm = label_context_stack_vm->next;
7881     }
7882 }
7883 \f
7884 /* Begin and end compound statements.  This is as simple as pushing
7885    and popping new statement lists from the tree.  */
7886
7887 tree
7888 c_begin_compound_stmt (bool do_scope)
7889 {
7890   tree stmt = push_stmt_list ();
7891   if (do_scope)
7892     push_scope ();
7893   return stmt;
7894 }
7895
7896 tree
7897 c_end_compound_stmt (tree stmt, bool do_scope)
7898 {
7899   tree block = NULL;
7900
7901   if (do_scope)
7902     {
7903       if (c_dialect_objc ())
7904         objc_clear_super_receiver ();
7905       block = pop_scope ();
7906     }
7907
7908   stmt = pop_stmt_list (stmt);
7909   stmt = c_build_bind_expr (block, stmt);
7910
7911   /* If this compound statement is nested immediately inside a statement
7912      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7913      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7914      STATEMENT_LISTs merge, and thus we can lose track of what statement
7915      was really last.  */
7916   if (cur_stmt_list
7917       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7918       && TREE_CODE (stmt) != BIND_EXPR)
7919     {
7920       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7921       TREE_SIDE_EFFECTS (stmt) = 1;
7922     }
7923
7924   return stmt;
7925 }
7926
7927 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7928    when the current scope is exited.  EH_ONLY is true when this is not
7929    meant to apply to normal control flow transfer.  */
7930
7931 void
7932 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7933 {
7934   enum tree_code code;
7935   tree stmt, list;
7936   bool stmt_expr;
7937
7938   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7939   stmt = build_stmt (code, NULL, cleanup);
7940   add_stmt (stmt);
7941   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7942   list = push_stmt_list ();
7943   TREE_OPERAND (stmt, 0) = list;
7944   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7945 }
7946 \f
7947 /* Build a binary-operation expression without default conversions.
7948    CODE is the kind of expression to build.
7949    LOCATION is the operator's location.
7950    This function differs from `build' in several ways:
7951    the data type of the result is computed and recorded in it,
7952    warnings are generated if arg data types are invalid,
7953    special handling for addition and subtraction of pointers is known,
7954    and some optimization is done (operations on narrow ints
7955    are done in the narrower type when that gives the same result).
7956    Constant folding is also done before the result is returned.
7957
7958    Note that the operands will never have enumeral types, or function
7959    or array types, because either they will have the default conversions
7960    performed or they have both just been converted to some other type in which
7961    the arithmetic is to be done.  */
7962
7963 tree
7964 build_binary_op (location_t location, enum tree_code code,
7965                  tree orig_op0, tree orig_op1, int convert_p)
7966 {
7967   tree type0, type1;
7968   enum tree_code code0, code1;
7969   tree op0, op1;
7970   tree ret = error_mark_node;
7971   const char *invalid_op_diag;
7972
7973   /* Expression code to give to the expression when it is built.
7974      Normally this is CODE, which is what the caller asked for,
7975      but in some special cases we change it.  */
7976   enum tree_code resultcode = code;
7977
7978   /* Data type in which the computation is to be performed.
7979      In the simplest cases this is the common type of the arguments.  */
7980   tree result_type = NULL;
7981
7982   /* Nonzero means operands have already been type-converted
7983      in whatever way is necessary.
7984      Zero means they need to be converted to RESULT_TYPE.  */
7985   int converted = 0;
7986
7987   /* Nonzero means create the expression with this type, rather than
7988      RESULT_TYPE.  */
7989   tree build_type = 0;
7990
7991   /* Nonzero means after finally constructing the expression
7992      convert it to this type.  */
7993   tree final_type = 0;
7994
7995   /* Nonzero if this is an operation like MIN or MAX which can
7996      safely be computed in short if both args are promoted shorts.
7997      Also implies COMMON.
7998      -1 indicates a bitwise operation; this makes a difference
7999      in the exact conditions for when it is safe to do the operation
8000      in a narrower mode.  */
8001   int shorten = 0;
8002
8003   /* Nonzero if this is a comparison operation;
8004      if both args are promoted shorts, compare the original shorts.
8005      Also implies COMMON.  */
8006   int short_compare = 0;
8007
8008   /* Nonzero if this is a right-shift operation, which can be computed on the
8009      original short and then promoted if the operand is a promoted short.  */
8010   int short_shift = 0;
8011
8012   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
8013   int common = 0;
8014
8015   /* True means types are compatible as far as ObjC is concerned.  */
8016   bool objc_ok;
8017
8018   if (location == UNKNOWN_LOCATION)
8019     location = input_location;
8020
8021   if (convert_p)
8022     {
8023       op0 = default_conversion (orig_op0);
8024       op1 = default_conversion (orig_op1);
8025     }
8026   else
8027     {
8028       op0 = orig_op0;
8029       op1 = orig_op1;
8030     }
8031
8032   type0 = TREE_TYPE (op0);
8033   type1 = TREE_TYPE (op1);
8034
8035   /* The expression codes of the data types of the arguments tell us
8036      whether the arguments are integers, floating, pointers, etc.  */
8037   code0 = TREE_CODE (type0);
8038   code1 = TREE_CODE (type1);
8039
8040   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
8041   STRIP_TYPE_NOPS (op0);
8042   STRIP_TYPE_NOPS (op1);
8043
8044   /* If an error was already reported for one of the arguments,
8045      avoid reporting another error.  */
8046
8047   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8048     return error_mark_node;
8049
8050   if ((invalid_op_diag
8051        = targetm.invalid_binary_op (code, type0, type1)))
8052     {
8053       error_at (location, invalid_op_diag);
8054       return error_mark_node;
8055     }
8056
8057   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
8058
8059   switch (code)
8060     {
8061     case PLUS_EXPR:
8062       /* Handle the pointer + int case.  */
8063       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8064         {
8065           ret = pointer_int_sum (PLUS_EXPR, op0, op1);
8066           goto return_build_binary_op;
8067         }
8068       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
8069         {
8070           ret = pointer_int_sum (PLUS_EXPR, op1, op0);
8071           goto return_build_binary_op;
8072         }
8073       else
8074         common = 1;
8075       break;
8076
8077     case MINUS_EXPR:
8078       /* Subtraction of two similar pointers.
8079          We must subtract them as integers, then divide by object size.  */
8080       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
8081           && comp_target_types (type0, type1))
8082         {
8083           ret = pointer_diff (op0, op1);
8084           goto return_build_binary_op;
8085         }
8086       /* Handle pointer minus int.  Just like pointer plus int.  */
8087       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8088         {
8089           ret = pointer_int_sum (MINUS_EXPR, op0, op1);
8090           goto return_build_binary_op;
8091         }
8092       else
8093         common = 1;
8094       break;
8095
8096     case MULT_EXPR:
8097       common = 1;
8098       break;
8099
8100     case TRUNC_DIV_EXPR:
8101     case CEIL_DIV_EXPR:
8102     case FLOOR_DIV_EXPR:
8103     case ROUND_DIV_EXPR:
8104     case EXACT_DIV_EXPR:
8105       warn_for_div_by_zero (location, op1);
8106
8107       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8108            || code0 == FIXED_POINT_TYPE
8109            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8110           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8111               || code1 == FIXED_POINT_TYPE
8112               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
8113         {
8114           enum tree_code tcode0 = code0, tcode1 = code1;
8115
8116           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
8117             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
8118           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
8119             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
8120
8121           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
8122               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
8123             resultcode = RDIV_EXPR;
8124           else
8125             /* Although it would be tempting to shorten always here, that
8126                loses on some targets, since the modulo instruction is
8127                undefined if the quotient can't be represented in the
8128                computation mode.  We shorten only if unsigned or if
8129                dividing by something we know != -1.  */
8130             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8131                        || (TREE_CODE (op1) == INTEGER_CST
8132                            && !integer_all_onesp (op1)));
8133           common = 1;
8134         }
8135       break;
8136
8137     case BIT_AND_EXPR:
8138     case BIT_IOR_EXPR:
8139     case BIT_XOR_EXPR:
8140       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8141         shorten = -1;
8142       /* Allow vector types which are not floating point types.   */
8143       else if (code0 == VECTOR_TYPE
8144                && code1 == VECTOR_TYPE
8145                && !VECTOR_FLOAT_TYPE_P (type0)
8146                && !VECTOR_FLOAT_TYPE_P (type1))
8147         common = 1;
8148       break;
8149
8150     case TRUNC_MOD_EXPR:
8151     case FLOOR_MOD_EXPR:
8152       warn_for_div_by_zero (location, op1);
8153
8154       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8155         {
8156           /* Although it would be tempting to shorten always here, that loses
8157              on some targets, since the modulo instruction is undefined if the
8158              quotient can't be represented in the computation mode.  We shorten
8159              only if unsigned or if dividing by something we know != -1.  */
8160           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8161                      || (TREE_CODE (op1) == INTEGER_CST
8162                          && !integer_all_onesp (op1)));
8163           common = 1;
8164         }
8165       break;
8166
8167     case TRUTH_ANDIF_EXPR:
8168     case TRUTH_ORIF_EXPR:
8169     case TRUTH_AND_EXPR:
8170     case TRUTH_OR_EXPR:
8171     case TRUTH_XOR_EXPR:
8172       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8173            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8174            || code0 == FIXED_POINT_TYPE)
8175           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8176               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8177               || code1 == FIXED_POINT_TYPE))
8178         {
8179           /* Result of these operations is always an int,
8180              but that does not mean the operands should be
8181              converted to ints!  */
8182           result_type = integer_type_node;
8183           op0 = c_common_truthvalue_conversion (location, op0);
8184           op1 = c_common_truthvalue_conversion (location, op1);
8185           converted = 1;
8186         }
8187       break;
8188
8189       /* Shift operations: result has same type as first operand;
8190          always convert second operand to int.
8191          Also set SHORT_SHIFT if shifting rightward.  */
8192
8193     case RSHIFT_EXPR:
8194       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8195           && code1 == INTEGER_TYPE)
8196         {
8197           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8198             {
8199               if (tree_int_cst_sgn (op1) < 0)
8200                 warning (0, "right shift count is negative");
8201               else
8202                 {
8203                   if (!integer_zerop (op1))
8204                     short_shift = 1;
8205
8206                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8207                     warning (0, "right shift count >= width of type");
8208                 }
8209             }
8210
8211           /* Use the type of the value to be shifted.  */
8212           result_type = type0;
8213           /* Convert the shift-count to an integer, regardless of size
8214              of value being shifted.  */
8215           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8216             op1 = convert (integer_type_node, op1);
8217           /* Avoid converting op1 to result_type later.  */
8218           converted = 1;
8219         }
8220       break;
8221
8222     case LSHIFT_EXPR:
8223       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8224           && code1 == INTEGER_TYPE)
8225         {
8226           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8227             {
8228               if (tree_int_cst_sgn (op1) < 0)
8229                 warning (0, "left shift count is negative");
8230
8231               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8232                 warning (0, "left shift count >= width of type");
8233             }
8234
8235           /* Use the type of the value to be shifted.  */
8236           result_type = type0;
8237           /* Convert the shift-count to an integer, regardless of size
8238              of value being shifted.  */
8239           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8240             op1 = convert (integer_type_node, op1);
8241           /* Avoid converting op1 to result_type later.  */
8242           converted = 1;
8243         }
8244       break;
8245
8246     case EQ_EXPR:
8247     case NE_EXPR:
8248       if (FLOAT_TYPE_P (type0) || FLOAT_TYPE_P (type1))
8249         warning_at (location,
8250                     OPT_Wfloat_equal,
8251                     "comparing floating point with == or != is unsafe");
8252       /* Result of comparison is always int,
8253          but don't convert the args to int!  */
8254       build_type = integer_type_node;
8255       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8256            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8257           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8258               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8259         short_compare = 1;
8260       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8261         {
8262           tree tt0 = TREE_TYPE (type0);
8263           tree tt1 = TREE_TYPE (type1);
8264           /* Anything compares with void *.  void * compares with anything.
8265              Otherwise, the targets must be compatible
8266              and both must be object or both incomplete.  */
8267           if (comp_target_types (type0, type1))
8268             result_type = common_pointer_type (type0, type1);
8269           else if (VOID_TYPE_P (tt0))
8270             {
8271               /* op0 != orig_op0 detects the case of something
8272                  whose value is 0 but which isn't a valid null ptr const.  */
8273               if (pedantic && !null_pointer_constant_p (orig_op0)
8274                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8275                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8276                          "comparison of %<void *%> with function pointer");
8277             }
8278           else if (VOID_TYPE_P (tt1))
8279             {
8280               if (pedantic && !null_pointer_constant_p (orig_op1)
8281                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8282                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8283                          "comparison of %<void *%> with function pointer");
8284             }
8285           else
8286             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8287             if (!objc_ok)
8288               pedwarn (location, 0,
8289                        "comparison of distinct pointer types lacks a cast");
8290
8291           if (result_type == NULL_TREE)
8292             result_type = ptr_type_node;
8293         }
8294       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8295         {
8296           if (TREE_CODE (op0) == ADDR_EXPR
8297               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8298             warning_at (location,
8299                         OPT_Waddress, "the address of %qD will never be NULL",
8300                         TREE_OPERAND (op0, 0));
8301           result_type = type0;
8302         }
8303       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8304         {
8305           if (TREE_CODE (op1) == ADDR_EXPR
8306               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8307             warning_at (location,
8308                         OPT_Waddress, "the address of %qD will never be NULL",
8309                         TREE_OPERAND (op1, 0));
8310           result_type = type1;
8311         }
8312       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8313         {
8314           result_type = type0;
8315           pedwarn (location, 0, "comparison between pointer and integer");
8316         }
8317       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8318         {
8319           result_type = type1;
8320           pedwarn (location, 0, "comparison between pointer and integer");
8321         }
8322       break;
8323
8324     case LE_EXPR:
8325     case GE_EXPR:
8326     case LT_EXPR:
8327     case GT_EXPR:
8328       build_type = integer_type_node;
8329       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8330            || code0 == FIXED_POINT_TYPE)
8331           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8332               || code1 == FIXED_POINT_TYPE))
8333         short_compare = 1;
8334       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8335         {
8336           if (comp_target_types (type0, type1))
8337             {
8338               result_type = common_pointer_type (type0, type1);
8339               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8340                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8341                 pedwarn (location, 0,
8342                          "comparison of complete and incomplete pointers");
8343               else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8344                 pedwarn (location, OPT_pedantic, "ISO C forbids "
8345                          "ordered comparisons of pointers to functions");
8346             }
8347           else
8348             {
8349               result_type = ptr_type_node;
8350               pedwarn (location, 0,
8351                        "comparison of distinct pointer types lacks a cast");
8352             }
8353         }
8354       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8355         {
8356           result_type = type0;
8357           if (pedantic)
8358             pedwarn (location, OPT_pedantic,
8359                      "ordered comparison of pointer with integer zero");
8360           else if (extra_warnings)
8361             warning_at (location, OPT_Wextra,
8362                      "ordered comparison of pointer with integer zero");
8363         }
8364       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8365         {
8366           result_type = type1;
8367           pedwarn (location, OPT_pedantic,
8368                    "ordered comparison of pointer with integer zero");
8369         }
8370       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8371         {
8372           result_type = type0;
8373           pedwarn (location, 0, "comparison between pointer and integer");
8374         }
8375       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8376         {
8377           result_type = type1;
8378           pedwarn (location, 0, "comparison between pointer and integer");
8379         }
8380       break;
8381
8382     default:
8383       gcc_unreachable ();
8384     }
8385
8386   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8387     return error_mark_node;
8388
8389   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8390       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8391           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8392                                                     TREE_TYPE (type1))))
8393     {
8394       binary_op_error (location, code, type0, type1);
8395       return error_mark_node;
8396     }
8397
8398   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8399        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8400       &&
8401       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8402        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8403     {
8404       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8405
8406       if (shorten || common || short_compare)
8407         {
8408           result_type = c_common_type (type0, type1);
8409           if (result_type == error_mark_node)
8410             return error_mark_node;
8411         }
8412
8413       /* For certain operations (which identify themselves by shorten != 0)
8414          if both args were extended from the same smaller type,
8415          do the arithmetic in that type and then extend.
8416
8417          shorten !=0 and !=1 indicates a bitwise operation.
8418          For them, this optimization is safe only if
8419          both args are zero-extended or both are sign-extended.
8420          Otherwise, we might change the result.
8421          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8422          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8423
8424       if (shorten && none_complex)
8425         {
8426           final_type = result_type;
8427           result_type = shorten_binary_op (result_type, op0, op1,
8428                                            shorten == -1);
8429         }
8430
8431       /* Shifts can be shortened if shifting right.  */
8432
8433       if (short_shift)
8434         {
8435           int unsigned_arg;
8436           tree arg0 = get_narrower (op0, &unsigned_arg);
8437
8438           final_type = result_type;
8439
8440           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8441             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8442
8443           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8444               /* We can shorten only if the shift count is less than the
8445                  number of bits in the smaller type size.  */
8446               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8447               /* We cannot drop an unsigned shift after sign-extension.  */
8448               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8449             {
8450               /* Do an unsigned shift if the operand was zero-extended.  */
8451               result_type
8452                 = c_common_signed_or_unsigned_type (unsigned_arg,
8453                                                     TREE_TYPE (arg0));
8454               /* Convert value-to-be-shifted to that type.  */
8455               if (TREE_TYPE (op0) != result_type)
8456                 op0 = convert (result_type, op0);
8457               converted = 1;
8458             }
8459         }
8460
8461       /* Comparison operations are shortened too but differently.
8462          They identify themselves by setting short_compare = 1.  */
8463
8464       if (short_compare)
8465         {
8466           /* Don't write &op0, etc., because that would prevent op0
8467              from being kept in a register.
8468              Instead, make copies of the our local variables and
8469              pass the copies by reference, then copy them back afterward.  */
8470           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8471           enum tree_code xresultcode = resultcode;
8472           tree val
8473             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8474
8475           if (val != 0)
8476             {
8477               ret = val;
8478               goto return_build_binary_op;
8479             }
8480
8481           op0 = xop0, op1 = xop1;
8482           converted = 1;
8483           resultcode = xresultcode;
8484
8485           if (warn_sign_compare && !skip_evaluation)
8486             {
8487               warn_for_sign_compare (location, orig_op0, orig_op1, op0, op1,
8488                                      result_type, resultcode);
8489             }
8490         }
8491     }
8492
8493   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8494      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8495      Then the expression will be built.
8496      It will be given type FINAL_TYPE if that is nonzero;
8497      otherwise, it will be given type RESULT_TYPE.  */
8498
8499   if (!result_type)
8500     {
8501       binary_op_error (location, code, TREE_TYPE (op0), TREE_TYPE (op1));
8502       return error_mark_node;
8503     }
8504
8505   if (!converted)
8506     {
8507       if (TREE_TYPE (op0) != result_type)
8508         op0 = convert_and_check (result_type, op0);
8509       if (TREE_TYPE (op1) != result_type)
8510         op1 = convert_and_check (result_type, op1);
8511
8512       /* This can happen if one operand has a vector type, and the other
8513          has a different type.  */
8514       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8515         return error_mark_node;
8516     }
8517
8518   if (build_type == NULL_TREE)
8519     build_type = result_type;
8520
8521   /* Treat expressions in initializers specially as they can't trap.  */
8522   ret = require_constant_value ? fold_build2_initializer (resultcode,
8523                                                           build_type,
8524                                                           op0, op1)
8525                                : fold_build2 (resultcode, build_type,
8526                                               op0, op1);
8527   if (final_type != 0)
8528     ret = convert (final_type, ret);
8529
8530  return_build_binary_op:
8531   gcc_assert (ret != error_mark_node);
8532   protected_set_expr_location (ret, location);
8533   return ret;
8534 }
8535
8536
8537 /* Convert EXPR to be a truth-value, validating its type for this
8538    purpose.  LOCATION is the source location for the expression.  */
8539
8540 tree
8541 c_objc_common_truthvalue_conversion (location_t location, tree expr)
8542 {
8543   switch (TREE_CODE (TREE_TYPE (expr)))
8544     {
8545     case ARRAY_TYPE:
8546       error_at (location, "used array that cannot be converted to pointer where scalar is required");
8547       return error_mark_node;
8548
8549     case RECORD_TYPE:
8550       error_at (location, "used struct type value where scalar is required");
8551       return error_mark_node;
8552
8553     case UNION_TYPE:
8554       error_at (location, "used union type value where scalar is required");
8555       return error_mark_node;
8556
8557     case FUNCTION_TYPE:
8558       gcc_unreachable ();
8559
8560     default:
8561       break;
8562     }
8563
8564   /* ??? Should we also give an error for void and vectors rather than
8565      leaving those to give errors later?  */
8566   return c_common_truthvalue_conversion (location, expr);
8567 }
8568 \f
8569
8570 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8571    required.  */
8572
8573 tree
8574 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se)
8575 {
8576   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8577     {
8578       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8579       /* Executing a compound literal inside a function reinitializes
8580          it.  */
8581       if (!TREE_STATIC (decl))
8582         *se = true;
8583       return decl;
8584     }
8585   else
8586     return expr;
8587 }
8588 \f
8589 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8590
8591 tree
8592 c_begin_omp_parallel (void)
8593 {
8594   tree block;
8595
8596   keep_next_level ();
8597   block = c_begin_compound_stmt (true);
8598
8599   return block;
8600 }
8601
8602 /* Generate OMP_PARALLEL, with CLAUSES and BLOCK as its compound statement.  */
8603
8604 tree
8605 c_finish_omp_parallel (tree clauses, tree block)
8606 {
8607   tree stmt;
8608
8609   block = c_end_compound_stmt (block, true);
8610
8611   stmt = make_node (OMP_PARALLEL);
8612   TREE_TYPE (stmt) = void_type_node;
8613   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8614   OMP_PARALLEL_BODY (stmt) = block;
8615
8616   return add_stmt (stmt);
8617 }
8618
8619 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8620
8621 tree
8622 c_begin_omp_task (void)
8623 {
8624   tree block;
8625
8626   keep_next_level ();
8627   block = c_begin_compound_stmt (true);
8628
8629   return block;
8630 }
8631
8632 /* Generate OMP_TASK, with CLAUSES and BLOCK as its compound statement.  */
8633
8634 tree
8635 c_finish_omp_task (tree clauses, tree block)
8636 {
8637   tree stmt;
8638
8639   block = c_end_compound_stmt (block, true);
8640
8641   stmt = make_node (OMP_TASK);
8642   TREE_TYPE (stmt) = void_type_node;
8643   OMP_TASK_CLAUSES (stmt) = clauses;
8644   OMP_TASK_BODY (stmt) = block;
8645
8646   return add_stmt (stmt);
8647 }
8648
8649 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8650    Remove any elements from the list that are invalid.  */
8651
8652 tree
8653 c_finish_omp_clauses (tree clauses)
8654 {
8655   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8656   tree c, t, *pc = &clauses;
8657   const char *name;
8658
8659   bitmap_obstack_initialize (NULL);
8660   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8661   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8662   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8663
8664   for (pc = &clauses, c = clauses; c ; c = *pc)
8665     {
8666       bool remove = false;
8667       bool need_complete = false;
8668       bool need_implicitly_determined = false;
8669
8670       switch (OMP_CLAUSE_CODE (c))
8671         {
8672         case OMP_CLAUSE_SHARED:
8673           name = "shared";
8674           need_implicitly_determined = true;
8675           goto check_dup_generic;
8676
8677         case OMP_CLAUSE_PRIVATE:
8678           name = "private";
8679           need_complete = true;
8680           need_implicitly_determined = true;
8681           goto check_dup_generic;
8682
8683         case OMP_CLAUSE_REDUCTION:
8684           name = "reduction";
8685           need_implicitly_determined = true;
8686           t = OMP_CLAUSE_DECL (c);
8687           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8688               || POINTER_TYPE_P (TREE_TYPE (t)))
8689             {
8690               error ("%qE has invalid type for %<reduction%>", t);
8691               remove = true;
8692             }
8693           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8694             {
8695               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8696               const char *r_name = NULL;
8697
8698               switch (r_code)
8699                 {
8700                 case PLUS_EXPR:
8701                 case MULT_EXPR:
8702                 case MINUS_EXPR:
8703                   break;
8704                 case BIT_AND_EXPR:
8705                   r_name = "&";
8706                   break;
8707                 case BIT_XOR_EXPR:
8708                   r_name = "^";
8709                   break;
8710                 case BIT_IOR_EXPR:
8711                   r_name = "|";
8712                   break;
8713                 case TRUTH_ANDIF_EXPR:
8714                   r_name = "&&";
8715                   break;
8716                 case TRUTH_ORIF_EXPR:
8717                   r_name = "||";
8718                   break;
8719                 default:
8720                   gcc_unreachable ();
8721                 }
8722               if (r_name)
8723                 {
8724                   error ("%qE has invalid type for %<reduction(%s)%>",
8725                          t, r_name);
8726                   remove = true;
8727                 }
8728             }
8729           goto check_dup_generic;
8730
8731         case OMP_CLAUSE_COPYPRIVATE:
8732           name = "copyprivate";
8733           goto check_dup_generic;
8734
8735         case OMP_CLAUSE_COPYIN:
8736           name = "copyin";
8737           t = OMP_CLAUSE_DECL (c);
8738           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8739             {
8740               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8741               remove = true;
8742             }
8743           goto check_dup_generic;
8744
8745         check_dup_generic:
8746           t = OMP_CLAUSE_DECL (c);
8747           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8748             {
8749               error ("%qE is not a variable in clause %qs", t, name);
8750               remove = true;
8751             }
8752           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8753                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8754                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8755             {
8756               error ("%qE appears more than once in data clauses", t);
8757               remove = true;
8758             }
8759           else
8760             bitmap_set_bit (&generic_head, DECL_UID (t));
8761           break;
8762
8763         case OMP_CLAUSE_FIRSTPRIVATE:
8764           name = "firstprivate";
8765           t = OMP_CLAUSE_DECL (c);
8766           need_complete = true;
8767           need_implicitly_determined = true;
8768           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8769             {
8770               error ("%qE is not a variable in clause %<firstprivate%>", t);
8771               remove = true;
8772             }
8773           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8774                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8775             {
8776               error ("%qE appears more than once in data clauses", t);
8777               remove = true;
8778             }
8779           else
8780             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8781           break;
8782
8783         case OMP_CLAUSE_LASTPRIVATE:
8784           name = "lastprivate";
8785           t = OMP_CLAUSE_DECL (c);
8786           need_complete = true;
8787           need_implicitly_determined = true;
8788           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8789             {
8790               error ("%qE is not a variable in clause %<lastprivate%>", t);
8791               remove = true;
8792             }
8793           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8794                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8795             {
8796               error ("%qE appears more than once in data clauses", t);
8797               remove = true;
8798             }
8799           else
8800             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8801           break;
8802
8803         case OMP_CLAUSE_IF:
8804         case OMP_CLAUSE_NUM_THREADS:
8805         case OMP_CLAUSE_SCHEDULE:
8806         case OMP_CLAUSE_NOWAIT:
8807         case OMP_CLAUSE_ORDERED:
8808         case OMP_CLAUSE_DEFAULT:
8809         case OMP_CLAUSE_UNTIED:
8810         case OMP_CLAUSE_COLLAPSE:
8811           pc = &OMP_CLAUSE_CHAIN (c);
8812           continue;
8813
8814         default:
8815           gcc_unreachable ();
8816         }
8817
8818       if (!remove)
8819         {
8820           t = OMP_CLAUSE_DECL (c);
8821
8822           if (need_complete)
8823             {
8824               t = require_complete_type (t);
8825               if (t == error_mark_node)
8826                 remove = true;
8827             }
8828
8829           if (need_implicitly_determined)
8830             {
8831               const char *share_name = NULL;
8832
8833               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8834                 share_name = "threadprivate";
8835               else switch (c_omp_predetermined_sharing (t))
8836                 {
8837                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8838                   break;
8839                 case OMP_CLAUSE_DEFAULT_SHARED:
8840                   share_name = "shared";
8841                   break;
8842                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8843                   share_name = "private";
8844                   break;
8845                 default:
8846                   gcc_unreachable ();
8847                 }
8848               if (share_name)
8849                 {
8850                   error ("%qE is predetermined %qs for %qs",
8851                          t, share_name, name);
8852                   remove = true;
8853                 }
8854             }
8855         }
8856
8857       if (remove)
8858         *pc = OMP_CLAUSE_CHAIN (c);
8859       else
8860         pc = &OMP_CLAUSE_CHAIN (c);
8861     }
8862
8863   bitmap_obstack_release (NULL);
8864   return clauses;
8865 }
8866
8867 /* Make a variant type in the proper way for C/C++, propagating qualifiers
8868    down to the element type of an array.  */
8869
8870 tree
8871 c_build_qualified_type (tree type, int type_quals)
8872 {
8873   if (type == error_mark_node)
8874     return type;
8875
8876   if (TREE_CODE (type) == ARRAY_TYPE)
8877     {
8878       tree t;
8879       tree element_type = c_build_qualified_type (TREE_TYPE (type),
8880                                                   type_quals);
8881
8882       /* See if we already have an identically qualified type.  */
8883       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
8884         {
8885           if (TYPE_QUALS (strip_array_types (t)) == type_quals
8886               && TYPE_NAME (t) == TYPE_NAME (type)
8887               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
8888               && attribute_list_equal (TYPE_ATTRIBUTES (t),
8889                                        TYPE_ATTRIBUTES (type)))
8890             break;
8891         }
8892       if (!t)
8893         {
8894           tree domain = TYPE_DOMAIN (type);
8895
8896           t = build_variant_type_copy (type);
8897           TREE_TYPE (t) = element_type;
8898
8899           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
8900               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
8901             SET_TYPE_STRUCTURAL_EQUALITY (t);
8902           else if (TYPE_CANONICAL (element_type) != element_type
8903                    || (domain && TYPE_CANONICAL (domain) != domain))
8904             {
8905               tree unqualified_canon
8906                 = build_array_type (TYPE_CANONICAL (element_type),
8907                                     domain? TYPE_CANONICAL (domain)
8908                                           : NULL_TREE);
8909               TYPE_CANONICAL (t)
8910                 = c_build_qualified_type (unqualified_canon, type_quals);
8911             }
8912           else
8913             TYPE_CANONICAL (t) = t;
8914         }
8915       return t;
8916     }
8917
8918   /* A restrict-qualified pointer type must be a pointer to object or
8919      incomplete type.  Note that the use of POINTER_TYPE_P also allows
8920      REFERENCE_TYPEs, which is appropriate for C++.  */
8921   if ((type_quals & TYPE_QUAL_RESTRICT)
8922       && (!POINTER_TYPE_P (type)
8923           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
8924     {
8925       error ("invalid use of %<restrict%>");
8926       type_quals &= ~TYPE_QUAL_RESTRICT;
8927     }
8928
8929   return build_qualified_type (type, type_quals);
8930 }