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
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file is part of the C front end.
  24    It contains routines to build C expressions given their operands,
  25    including computing the types of the result, C-specific error checks,
  26    and some optimization.  */
  27
  28 #include "config.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "tree.h"
  34 #include "langhooks.h"
  35 #include "c-tree.h"
  36 #include "tm_p.h"
  37 #include "flags.h"
  38 #include "output.h"
  39 #include "expr.h"
  40 #include "toplev.h"
  41 #include "intl.h"
  42 #include "ggc.h"
  43 #include "target.h"
  44 #include "tree-iterator.h"
  45 #include "tree-gimple.h"
  46 #include "tree-flow.h"
  47
  48 /* Possible cases of implicit bad conversions.  Used to select
  49    diagnostic messages in convert_for_assignment.  */
  50 enum impl_conv {
  51   ic_argpass,
  52   ic_argpass_nonproto,
  53   ic_assign,
  54   ic_init,
  55   ic_return
  56 };
  57
  58 /* The level of nesting inside "__alignof__".  */
  59 int in_alignof;
  60
  61 /* The level of nesting inside "sizeof".  */
  62 int in_sizeof;
  63
  64 /* The level of nesting inside "typeof".  */
  65 int in_typeof;
  66
  67 struct c_label_context_se *label_context_stack_se;
  68 struct c_label_context_vm *label_context_stack_vm;
  69
  70 /* Nonzero if we've already printed a "missing braces around initializer"
  71    message within this initializer.  */
  72 static int missing_braces_mentioned;
  73
  74 static int require_constant_value;
  75 static int require_constant_elements;
  76
  77 static bool null_pointer_constant_p (const_tree);
  78 static tree qualify_type (tree, tree);
  79 static int tagged_types_tu_compatible_p (const_tree, const_tree);
  80 static int comp_target_types (tree, tree);
  81 static int function_types_compatible_p (const_tree, const_tree);
  82 static int type_lists_compatible_p (const_tree, const_tree);
  83 static tree decl_constant_value_for_broken_optimization (tree);
  84 static tree lookup_field (tree, tree);
  85 static int convert_arguments (int, tree *, tree, tree, tree, tree);
  86 static tree pointer_diff (tree, tree);
  87 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  88                                     int);
  89 static tree valid_compound_expr_initializer (tree, tree);
  90 static void push_string (const char *);
  91 static void push_member_name (tree);
  92 static int spelling_length (void);
  93 static char *print_spelling (char *);
  94 static void warning_init (const char *);
  95 static tree digest_init (tree, tree, bool, int);
  96 static void output_init_element (tree, bool, tree, tree, int);
  97 static void output_pending_init_elements (int);
  98 static int set_designator (int);
  99 static void push_range_stack (tree);
 100 static void add_pending_init (tree, tree);
 101 static void set_nonincremental_init (void);
 102 static void set_nonincremental_init_from_string (tree);
 103 static tree find_init_member (tree);
 104 static void readonly_error (tree, enum lvalue_use);
 105 static int lvalue_or_else (const_tree, enum lvalue_use);
 106 static int lvalue_p (const_tree);
 107 static void record_maybe_used_decl (tree);
 108 static int comptypes_internal (const_tree, const_tree);
 109 \f
 110 /* Return true if EXP is a null pointer constant, false otherwise.  */
 111
 112 static bool
 113 null_pointer_constant_p (const_tree expr)
 114 {
 115   /* This should really operate on c_expr structures, but they aren't
 116      yet available everywhere required.  */
 117   tree type = TREE_TYPE (expr);
 118   return (TREE_CODE (expr) == INTEGER_CST
 119           && !TREE_OVERFLOW (expr)
 120           && integer_zerop (expr)
 121           && (INTEGRAL_TYPE_P (type)
 122               || (TREE_CODE (type) == POINTER_TYPE
 123                   && VOID_TYPE_P (TREE_TYPE (type))
 124                   && TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
 125 }
 126 \f/* This is a cache to hold if two types are compatible or not.  */
 127
 128 struct tagged_tu_seen_cache {
 129   const struct tagged_tu_seen_cache * next;
 130   const_tree t1;
 131   const_tree t2;
 132   /* The return value of tagged_types_tu_compatible_p if we had seen
 133      these two types already.  */
 134   int val;
 135 };
 136
 137 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 138 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 139
 140 /* Do `exp = require_complete_type (exp);' to make sure exp
 141    does not have an incomplete type.  (That includes void types.)  */
 142
 143 tree
 144 require_complete_type (tree value)
 145 {
 146   tree type = TREE_TYPE (value);
 147
 148   if (value == error_mark_node || type == error_mark_node)
 149     return error_mark_node;
 150
 151   /* First, detect a valid value with a complete type.  */
 152   if (COMPLETE_TYPE_P (type))
 153     return value;
 154
 155   c_incomplete_type_error (value, type);
 156   return error_mark_node;
 157 }
 158
 159 /* Print an error message for invalid use of an incomplete type.
 160    VALUE is the expression that was used (or 0 if that isn't known)
 161    and TYPE is the type that was invalid.  */
 162
 163 void
 164 c_incomplete_type_error (const_tree value, const_tree type)
 165 {
 166   const char *type_code_string;
 167
 168   /* Avoid duplicate error message.  */
 169   if (TREE_CODE (type) == ERROR_MARK)
 170     return;
 171
 172   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 173                      || TREE_CODE (value) == PARM_DECL))
 174     error ("%qD has an incomplete type", value);
 175   else
 176     {
 177     retry:
 178       /* We must print an error message.  Be clever about what it says.  */
 179
 180       switch (TREE_CODE (type))
 181         {
 182         case RECORD_TYPE:
 183           type_code_string = "struct";
 184           break;
 185
 186         case UNION_TYPE:
 187           type_code_string = "union";
 188           break;
 189
 190         case ENUMERAL_TYPE:
 191           type_code_string = "enum";
 192           break;
 193
 194         case VOID_TYPE:
 195           error ("invalid use of void expression");
 196           return;
 197
 198         case ARRAY_TYPE:
 199           if (TYPE_DOMAIN (type))
 200             {
 201               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 202                 {
 203                   error ("invalid use of flexible array member");
 204                   return;
 205                 }
 206               type = TREE_TYPE (type);
 207               goto retry;
 208             }
 209           error ("invalid use of array with unspecified bounds");
 210           return;
 211
 212         default:
 213           gcc_unreachable ();
 214         }
 215
 216       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 217         error ("invalid use of undefined type %<%s %E%>",
 218                type_code_string, TYPE_NAME (type));
 219       else
 220         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 221         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 222     }
 223 }
 224
 225 /* Given a type, apply default promotions wrt unnamed function
 226    arguments and return the new type.  */
 227
 228 tree
 229 c_type_promotes_to (tree type)
 230 {
 231   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 232     return double_type_node;
 233
 234   if (c_promoting_integer_type_p (type))
 235     {
 236       /* Preserve unsignedness if not really getting any wider.  */
 237       if (TYPE_UNSIGNED (type)
 238           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 239         return unsigned_type_node;
 240       return integer_type_node;
 241     }
 242
 243   return type;
 244 }
 245
 246 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 247    as well as those of TYPE.  */
 248
 249 static tree
 250 qualify_type (tree type, tree like)
 251 {
 252   return c_build_qualified_type (type,
 253                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 254 }
 255
 256 /* Return true iff the given tree T is a variable length array.  */
 257
 258 bool
 259 c_vla_type_p (const_tree t)
 260 {
 261   if (TREE_CODE (t) == ARRAY_TYPE
 262       && C_TYPE_VARIABLE_SIZE (t))
 263     return true;
 264   return false;
 265 }
 266 \f
 267 /* Return the composite type of two compatible types.
 268
 269    We assume that comptypes has already been done and returned
 270    nonzero; if that isn't so, this may crash.  In particular, we
 271    assume that qualifiers match.  */
 272
 273 tree
 274 composite_type (tree t1, tree t2)
 275 {
 276   enum tree_code code1;
 277   enum tree_code code2;
 278   tree attributes;
 279
 280   /* Save time if the two types are the same.  */
 281
 282   if (t1 == t2) return t1;
 283
 284   /* If one type is nonsense, use the other.  */
 285   if (t1 == error_mark_node)
 286     return t2;
 287   if (t2 == error_mark_node)
 288     return t1;
 289
 290   code1 = TREE_CODE (t1);
 291   code2 = TREE_CODE (t2);
 292
 293   /* Merge the attributes.  */
 294   attributes = targetm.merge_type_attributes (t1, t2);
 295
 296   /* If one is an enumerated type and the other is the compatible
 297      integer type, the composite type might be either of the two
 298      (DR#013 question 3).  For consistency, use the enumerated type as
 299      the composite type.  */
 300
 301   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 302     return t1;
 303   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 304     return t2;
 305
 306   gcc_assert (code1 == code2);
 307
 308   switch (code1)
 309     {
 310     case POINTER_TYPE:
 311       /* For two pointers, do this recursively on the target type.  */
 312       {
 313         tree pointed_to_1 = TREE_TYPE (t1);
 314         tree pointed_to_2 = TREE_TYPE (t2);
 315         tree target = composite_type (pointed_to_1, pointed_to_2);
 316         t1 = build_pointer_type (target);
 317         t1 = build_type_attribute_variant (t1, attributes);
 318         return qualify_type (t1, t2);
 319       }
 320
 321     case ARRAY_TYPE:
 322       {
 323         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 324         int quals;
 325         tree unqual_elt;
 326         tree d1 = TYPE_DOMAIN (t1);
 327         tree d2 = TYPE_DOMAIN (t2);
 328         bool d1_variable, d2_variable;
 329         bool d1_zero, d2_zero;
 330
 331         /* We should not have any type quals on arrays at all.  */
 332         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 333
 334         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 335         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 336
 337         d1_variable = (!d1_zero
 338                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 339                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 340         d2_variable = (!d2_zero
 341                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 342                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 343         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 344         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 345
 346         /* Save space: see if the result is identical to one of the args.  */
 347         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 348             && (d2_variable || d2_zero || !d1_variable))
 349           return build_type_attribute_variant (t1, attributes);
 350         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 351             && (d1_variable || d1_zero || !d2_variable))
 352           return build_type_attribute_variant (t2, attributes);
 353
 354         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 355           return build_type_attribute_variant (t1, attributes);
 356         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 357           return build_type_attribute_variant (t2, attributes);
 358
 359         /* Merge the element types, and have a size if either arg has
 360            one.  We may have qualifiers on the element types.  To set
 361            up TYPE_MAIN_VARIANT correctly, we need to form the
 362            composite of the unqualified types and add the qualifiers
 363            back at the end.  */
 364         quals = TYPE_QUALS (strip_array_types (elt));
 365         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 366         t1 = build_array_type (unqual_elt,
 367                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 368                                              && (d2_variable
 369                                                  || d2_zero
 370                                                  || !d1_variable))
 371                                             ? t1
 372                                             : t2));
 373         t1 = c_build_qualified_type (t1, quals);
 374         return build_type_attribute_variant (t1, attributes);
 375       }
 376
 377     case ENUMERAL_TYPE:
 378     case RECORD_TYPE:
 379     case UNION_TYPE:
 380       if (attributes != NULL)
 381         {
 382           /* Try harder not to create a new aggregate type.  */
 383           if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes))
 384             return t1;
 385           if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes))
 386             return t2;
 387         }
 388       return build_type_attribute_variant (t1, attributes);
 389
 390     case FUNCTION_TYPE:
 391       /* Function types: prefer the one that specified arg types.
 392          If both do, merge the arg types.  Also merge the return types.  */
 393       {
 394         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 395         tree p1 = TYPE_ARG_TYPES (t1);
 396         tree p2 = TYPE_ARG_TYPES (t2);
 397         int len;
 398         tree newargs, n;
 399         int i;
 400
 401         /* Save space: see if the result is identical to one of the args.  */
 402         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 403           return build_type_attribute_variant (t1, attributes);
 404         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 405           return build_type_attribute_variant (t2, attributes);
 406
 407         /* Simple way if one arg fails to specify argument types.  */
 408         if (TYPE_ARG_TYPES (t1) == 0)
 409          {
 410             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 411             t1 = build_type_attribute_variant (t1, attributes);
 412             return qualify_type (t1, t2);
 413          }
 414         if (TYPE_ARG_TYPES (t2) == 0)
 415          {
 416            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 417            t1 = build_type_attribute_variant (t1, attributes);
 418            return qualify_type (t1, t2);
 419          }
 420
 421         /* If both args specify argument types, we must merge the two
 422            lists, argument by argument.  */
 423         /* Tell global_bindings_p to return false so that variable_size
 424            doesn't die on VLAs in parameter types.  */
 425         c_override_global_bindings_to_false = true;
 426
 427         len = list_length (p1);
 428         newargs = 0;
 429
 430         for (i = 0; i < len; i++)
 431           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 432
 433         n = newargs;
 434
 435         for (; p1;
 436              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 437           {
 438             /* A null type means arg type is not specified.
 439                Take whatever the other function type has.  */
 440             if (TREE_VALUE (p1) == 0)
 441               {
 442                 TREE_VALUE (n) = TREE_VALUE (p2);
 443                 goto parm_done;
 444               }
 445             if (TREE_VALUE (p2) == 0)
 446               {
 447                 TREE_VALUE (n) = TREE_VALUE (p1);
 448                 goto parm_done;
 449               }
 450
 451             /* Given  wait (union {union wait *u; int *i} *)
 452                and  wait (union wait *),
 453                prefer  union wait *  as type of parm.  */
 454             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 455                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 456               {
 457                 tree memb;
 458                 tree mv2 = TREE_VALUE (p2);
 459                 if (mv2 && mv2 != error_mark_node
 460                     && TREE_CODE (mv2) != ARRAY_TYPE)
 461                   mv2 = TYPE_MAIN_VARIANT (mv2);
 462                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 463                      memb; memb = TREE_CHAIN (memb))
 464                   {
 465                     tree mv3 = TREE_TYPE (memb);
 466                     if (mv3 && mv3 != error_mark_node
 467                         && TREE_CODE (mv3) != ARRAY_TYPE)
 468                       mv3 = TYPE_MAIN_VARIANT (mv3);
 469                     if (comptypes (mv3, mv2))
 470                       {
 471                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 472                                                          TREE_VALUE (p2));
 473                         if (pedantic)
 474                           pedwarn ("function types not truly compatible in ISO C");
 475                         goto parm_done;
 476                       }
 477                   }
 478               }
 479             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 480                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 481               {
 482                 tree memb;
 483                 tree mv1 = TREE_VALUE (p1);
 484                 if (mv1 && mv1 != error_mark_node
 485                     && TREE_CODE (mv1) != ARRAY_TYPE)
 486                   mv1 = TYPE_MAIN_VARIANT (mv1);
 487                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 488                      memb; memb = TREE_CHAIN (memb))
 489                   {
 490                     tree mv3 = TREE_TYPE (memb);
 491                     if (mv3 && mv3 != error_mark_node
 492                         && TREE_CODE (mv3) != ARRAY_TYPE)
 493                       mv3 = TYPE_MAIN_VARIANT (mv3);
 494                     if (comptypes (mv3, mv1))
 495                       {
 496                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 497                                                          TREE_VALUE (p1));
 498                         if (pedantic)
 499                           pedwarn ("function types not truly compatible in ISO C");
 500                         goto parm_done;
 501                       }
 502                   }
 503               }
 504             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 505           parm_done: ;
 506           }
 507
 508         c_override_global_bindings_to_false = false;
 509         t1 = build_function_type (valtype, newargs);
 510         t1 = qualify_type (t1, t2);
 511         /* ... falls through ...  */
 512       }
 513
 514     default:
 515       return build_type_attribute_variant (t1, attributes);
 516     }
 517
 518 }
 519
 520 /* Return the type of a conditional expression between pointers to
 521    possibly differently qualified versions of compatible types.
 522
 523    We assume that comp_target_types has already been done and returned
 524    nonzero; if that isn't so, this may crash.  */
 525
 526 static tree
 527 common_pointer_type (tree t1, tree t2)
 528 {
 529   tree attributes;
 530   tree pointed_to_1, mv1;
 531   tree pointed_to_2, mv2;
 532   tree target;
 533
 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   t1 = build_pointer_type (c_build_qualified_type
 561                            (target,
 562                             TYPE_QUALS (pointed_to_1) |
 563                             TYPE_QUALS (pointed_to_2)));
 564   return build_type_attribute_variant (t1, attributes);
 565 }
 566
 567 /* Return the common type for two arithmetic types under the usual
 568    arithmetic conversions.  The default conversions have already been
 569    applied, and enumerated types converted to their compatible integer
 570    types.  The resulting type is unqualified and has no attributes.
 571
 572    This is the type for the result of most arithmetic operations
 573    if the operands have the given two types.  */
 574
 575 static tree
 576 c_common_type (tree t1, tree t2)
 577 {
 578   enum tree_code code1;
 579   enum tree_code code2;
 580
 581   /* If one type is nonsense, use the other.  */
 582   if (t1 == error_mark_node)
 583     return t2;
 584   if (t2 == error_mark_node)
 585     return t1;
 586
 587   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 588     t1 = TYPE_MAIN_VARIANT (t1);
 589
 590   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 591     t2 = TYPE_MAIN_VARIANT (t2);
 592
 593   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 594     t1 = build_type_attribute_variant (t1, NULL_TREE);
 595
 596   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 597     t2 = build_type_attribute_variant (t2, NULL_TREE);
 598
 599   /* Save time if the two types are the same.  */
 600
 601   if (t1 == t2) return t1;
 602
 603   code1 = TREE_CODE (t1);
 604   code2 = TREE_CODE (t2);
 605
 606   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 607               || code1 == FIXED_POINT_TYPE || code1 == REAL_TYPE
 608               || code1 == INTEGER_TYPE);
 609   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 610               || code2 == FIXED_POINT_TYPE || code2 == REAL_TYPE
 611               || code2 == INTEGER_TYPE);
 612
 613   /* When one operand is a decimal float type, the other operand cannot be
 614      a generic float type or a complex type.  We also disallow vector types
 615      here.  */
 616   if ((DECIMAL_FLOAT_TYPE_P (t1) || DECIMAL_FLOAT_TYPE_P (t2))
 617       && !(DECIMAL_FLOAT_TYPE_P (t1) && DECIMAL_FLOAT_TYPE_P (t2)))
 618     {
 619       if (code1 == VECTOR_TYPE || code2 == VECTOR_TYPE)
 620         {
 621           error ("can%'t mix operands of decimal float and vector types");
 622           return error_mark_node;
 623         }
 624       if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 625         {
 626           error ("can%'t mix operands of decimal float and complex types");
 627           return error_mark_node;
 628         }
 629       if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 630         {
 631           error ("can%'t mix operands of decimal float and other float types");
 632           return error_mark_node;
 633         }
 634     }
 635
 636   /* If one type is a vector type, return that type.  (How the usual
 637      arithmetic conversions apply to the vector types extension is not
 638      precisely specified.)  */
 639   if (code1 == VECTOR_TYPE)
 640     return t1;
 641
 642   if (code2 == VECTOR_TYPE)
 643     return t2;
 644
 645   /* If one type is complex, form the common type of the non-complex
 646      components, then make that complex.  Use T1 or T2 if it is the
 647      required type.  */
 648   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 649     {
 650       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 651       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 652       tree subtype = c_common_type (subtype1, subtype2);
 653
 654       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 655         return t1;
 656       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 657         return t2;
 658       else
 659         return build_complex_type (subtype);
 660     }
 661
 662   /* If only one is real, use it as the result.  */
 663
 664   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 665     return t1;
 666
 667   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 668     return t2;
 669
 670   /* If both are real and either are decimal floating point types, use
 671      the decimal floating point type with the greater precision. */
 672
 673   if (code1 == REAL_TYPE && code2 == REAL_TYPE)
 674     {
 675       if (TYPE_MAIN_VARIANT (t1) == dfloat128_type_node
 676           || TYPE_MAIN_VARIANT (t2) == dfloat128_type_node)
 677         return dfloat128_type_node;
 678       else if (TYPE_MAIN_VARIANT (t1) == dfloat64_type_node
 679                || TYPE_MAIN_VARIANT (t2) == dfloat64_type_node)
 680         return dfloat64_type_node;
 681       else if (TYPE_MAIN_VARIANT (t1) == dfloat32_type_node
 682                || TYPE_MAIN_VARIANT (t2) == dfloat32_type_node)
 683         return dfloat32_type_node;
 684     }
 685
 686   /* Deal with fixed-point types.  */
 687   if (code1 == FIXED_POINT_TYPE || code2 == FIXED_POINT_TYPE)
 688     {
 689       unsigned int unsignedp = 0, satp = 0;
 690       enum machine_mode m1, m2;
 691       unsigned int fbit1, ibit1, fbit2, ibit2, max_fbit, max_ibit;
 692
 693       m1 = TYPE_MODE (t1);
 694       m2 = TYPE_MODE (t2);
 695
 696       /* If one input type is saturating, the result type is saturating.  */
 697       if (TYPE_SATURATING (t1) || TYPE_SATURATING (t2))
 698         satp = 1;
 699
 700       /* If both fixed-point types are unsigned, the result type is unsigned.
 701          When mixing fixed-point and integer types, follow the sign of the
 702          fixed-point type.
 703          Otherwise, the result type is signed.  */
 704       if ((TYPE_UNSIGNED (t1) && TYPE_UNSIGNED (t2)
 705            && code1 == FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE)
 706           || (code1 == FIXED_POINT_TYPE && code2 != FIXED_POINT_TYPE
 707               && TYPE_UNSIGNED (t1))
 708           || (code1 != FIXED_POINT_TYPE && code2 == FIXED_POINT_TYPE
 709               && TYPE_UNSIGNED (t2)))
 710         unsignedp = 1;
 711
 712       /* The result type is signed.  */
 713       if (unsignedp == 0)
 714         {
 715           /* If the input type is unsigned, we need to convert to the
 716              signed type.  */
 717           if (code1 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t1))
 718             {
 719               unsigned char mclass = 0;
 720               if (GET_MODE_CLASS (m1) == MODE_UFRACT)
 721                 mclass = MODE_FRACT;
 722               else if (GET_MODE_CLASS (m1) == MODE_UACCUM)
 723                 mclass = MODE_ACCUM;
 724               else
 725                 gcc_unreachable ();
 726               m1 = mode_for_size (GET_MODE_PRECISION (m1), mclass, 0);
 727             }
 728           if (code2 == FIXED_POINT_TYPE && TYPE_UNSIGNED (t2))
 729             {
 730               unsigned char mclass = 0;
 731               if (GET_MODE_CLASS (m2) == MODE_UFRACT)
 732                 mclass = MODE_FRACT;
 733               else if (GET_MODE_CLASS (m2) == MODE_UACCUM)
 734                 mclass = MODE_ACCUM;
 735               else
 736                 gcc_unreachable ();
 737               m2 = mode_for_size (GET_MODE_PRECISION (m2), mclass, 0);
 738             }
 739         }
 740
 741       if (code1 == FIXED_POINT_TYPE)
 742         {
 743           fbit1 = GET_MODE_FBIT (m1);
 744           ibit1 = GET_MODE_IBIT (m1);
 745         }
 746       else
 747         {
 748           fbit1 = 0;
 749           /* Signed integers need to subtract one sign bit.  */
 750           ibit1 = TYPE_PRECISION (t1) - (!TYPE_UNSIGNED (t1));
 751         }
 752
 753       if (code2 == FIXED_POINT_TYPE)
 754         {
 755           fbit2 = GET_MODE_FBIT (m2);
 756           ibit2 = GET_MODE_IBIT (m2);
 757         }
 758       else
 759         {
 760           fbit2 = 0;
 761           /* Signed integers need to subtract one sign bit.  */
 762           ibit2 = TYPE_PRECISION (t2) - (!TYPE_UNSIGNED (t2));
 763         }
 764
 765       max_ibit = ibit1 >= ibit2 ?  ibit1 : ibit2;
 766       max_fbit = fbit1 >= fbit2 ?  fbit1 : fbit2;
 767       return c_common_fixed_point_type_for_size (max_ibit, max_fbit, unsignedp,
 768                                                  satp);
 769     }
 770
 771   /* Both real or both integers; use the one with greater precision.  */
 772
 773   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 774     return t1;
 775   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 776     return t2;
 777
 778   /* Same precision.  Prefer long longs to longs to ints when the
 779      same precision, following the C99 rules on integer type rank
 780      (which are equivalent to the C90 rules for C90 types).  */
 781
 782   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 783       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 784     return long_long_unsigned_type_node;
 785
 786   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 787       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 788     {
 789       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 790         return long_long_unsigned_type_node;
 791       else
 792         return long_long_integer_type_node;
 793     }
 794
 795   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 796       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 797     return long_unsigned_type_node;
 798
 799   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 800       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 801     {
 802       /* But preserve unsignedness from the other type,
 803          since long cannot hold all the values of an unsigned int.  */
 804       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 805         return long_unsigned_type_node;
 806       else
 807         return long_integer_type_node;
 808     }
 809
 810   /* Likewise, prefer long double to double even if same size.  */
 811   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 812       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 813     return long_double_type_node;
 814
 815   /* Otherwise prefer the unsigned one.  */
 816
 817   if (TYPE_UNSIGNED (t1))
 818     return t1;
 819   else
 820     return t2;
 821 }
 822 \f
 823 /* Wrapper around c_common_type that is used by c-common.c and other
 824    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 825    are allowed here and are converted to their compatible integer types.
 826    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 827    preferably a non-Boolean type as the common type.  */
 828 tree
 829 common_type (tree t1, tree t2)
 830 {
 831   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 832     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 833   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 834     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 835
 836   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 837   if (TREE_CODE (t1) == BOOLEAN_TYPE
 838       && TREE_CODE (t2) == BOOLEAN_TYPE)
 839     return boolean_type_node;
 840
 841   /* If either type is BOOLEAN_TYPE, then return the other.  */
 842   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 843     return t2;
 844   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 845     return t1;
 846
 847   return c_common_type (t1, t2);
 848 }
 849
 850 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 851    or various other operations.  Return 2 if they are compatible
 852    but a warning may be needed if you use them together.  */
 853
 854 int
 855 comptypes (tree type1, tree type2)
 856 {
 857   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 858   int val;
 859
 860   val = comptypes_internal (type1, type2);
 861   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 862
 863   return val;
 864 }
 865 \f
 866 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 867    or various other operations.  Return 2 if they are compatible
 868    but a warning may be needed if you use them together.  This
 869    differs from comptypes, in that we don't free the seen types.  */
 870
 871 static int
 872 comptypes_internal (const_tree type1, const_tree type2)
 873 {
 874   const_tree t1 = type1;
 875   const_tree t2 = type2;
 876   int attrval, val;
 877
 878   /* Suppress errors caused by previously reported errors.  */
 879
 880   if (t1 == t2 || !t1 || !t2
 881       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 882     return 1;
 883
 884   /* If either type is the internal version of sizetype, return the
 885      language version.  */
 886   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 887       && TYPE_ORIG_SIZE_TYPE (t1))
 888     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 889
 890   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 891       && TYPE_ORIG_SIZE_TYPE (t2))
 892     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 893
 894
 895   /* Enumerated types are compatible with integer types, but this is
 896      not transitive: two enumerated types in the same translation unit
 897      are compatible with each other only if they are the same type.  */
 898
 899   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 900     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 901   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 902     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 903
 904   if (t1 == t2)
 905     return 1;
 906
 907   /* Different classes of types can't be compatible.  */
 908
 909   if (TREE_CODE (t1) != TREE_CODE (t2))
 910     return 0;
 911
 912   /* Qualifiers must match. C99 6.7.3p9 */
 913
 914   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 915     return 0;
 916
 917   /* Allow for two different type nodes which have essentially the same
 918      definition.  Note that we already checked for equality of the type
 919      qualifiers (just above).  */
 920
 921   if (TREE_CODE (t1) != ARRAY_TYPE
 922       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 923     return 1;
 924
 925   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 926   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 927      return 0;
 928
 929   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 930   val = 0;
 931
 932   switch (TREE_CODE (t1))
 933     {
 934     case POINTER_TYPE:
 935       /* Do not remove mode or aliasing information.  */
 936       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 937           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 938         break;
 939       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 940              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 941       break;
 942
 943     case FUNCTION_TYPE:
 944       val = function_types_compatible_p (t1, t2);
 945       break;
 946
 947     case ARRAY_TYPE:
 948       {
 949         tree d1 = TYPE_DOMAIN (t1);
 950         tree d2 = TYPE_DOMAIN (t2);
 951         bool d1_variable, d2_variable;
 952         bool d1_zero, d2_zero;
 953         val = 1;
 954
 955         /* Target types must match incl. qualifiers.  */
 956         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 957             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 958           return 0;
 959
 960         /* Sizes must match unless one is missing or variable.  */
 961         if (d1 == 0 || d2 == 0 || d1 == d2)
 962           break;
 963
 964         d1_zero = !TYPE_MAX_VALUE (d1);
 965         d2_zero = !TYPE_MAX_VALUE (d2);
 966
 967         d1_variable = (!d1_zero
 968                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 969                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 970         d2_variable = (!d2_zero
 971                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 972                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 973         d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
 974         d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
 975
 976         if (d1_variable || d2_variable)
 977           break;
 978         if (d1_zero && d2_zero)
 979           break;
 980         if (d1_zero || d2_zero
 981             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 982             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 983           val = 0;
 984
 985         break;
 986       }
 987
 988     case ENUMERAL_TYPE:
 989     case RECORD_TYPE:
 990     case UNION_TYPE:
 991       if (val != 1 && !same_translation_unit_p (t1, t2))
 992         {
 993           tree a1 = TYPE_ATTRIBUTES (t1);
 994           tree a2 = TYPE_ATTRIBUTES (t2);
 995
 996           if (! attribute_list_contained (a1, a2)
 997               && ! attribute_list_contained (a2, a1))
 998             break;
 999
1000           if (attrval != 2)
1001             return tagged_types_tu_compatible_p (t1, t2);
1002           val = tagged_types_tu_compatible_p (t1, t2);
1003         }
1004       break;
1005
1006     case VECTOR_TYPE:
1007       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1008             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
1009       break;
1010
1011     default:
1012       break;
1013     }
1014   return attrval == 2 && val == 1 ? 2 : val;
1015 }
1016
1017 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
1018    ignoring their qualifiers.  */
1019
1020 static int
1021 comp_target_types (tree ttl, tree ttr)
1022 {
1023   int val;
1024   tree mvl, mvr;
1025
1026   /* Do not lose qualifiers on element types of array types that are
1027      pointer targets by taking their TYPE_MAIN_VARIANT.  */
1028   mvl = TREE_TYPE (ttl);
1029   mvr = TREE_TYPE (ttr);
1030   if (TREE_CODE (mvl) != ARRAY_TYPE)
1031     mvl = TYPE_MAIN_VARIANT (mvl);
1032   if (TREE_CODE (mvr) != ARRAY_TYPE)
1033     mvr = TYPE_MAIN_VARIANT (mvr);
1034   val = comptypes (mvl, mvr);
1035
1036   if (val == 2 && pedantic)
1037     pedwarn ("types are not quite compatible");
1038   return val;
1039 }
1040 \f
1041 /* Subroutines of `comptypes'.  */
1042
1043 /* Determine whether two trees derive from the same translation unit.
1044    If the CONTEXT chain ends in a null, that tree's context is still
1045    being parsed, so if two trees have context chains ending in null,
1046    they're in the same translation unit.  */
1047 int
1048 same_translation_unit_p (const_tree t1, const_tree t2)
1049 {
1050   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
1051     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
1052       {
1053       case tcc_declaration:
1054         t1 = DECL_CONTEXT (t1); break;
1055       case tcc_type:
1056         t1 = TYPE_CONTEXT (t1); break;
1057       case tcc_exceptional:
1058         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
1059       default: gcc_unreachable ();
1060       }
1061
1062   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
1063     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
1064       {
1065       case tcc_declaration:
1066         t2 = DECL_CONTEXT (t2); break;
1067       case tcc_type:
1068         t2 = TYPE_CONTEXT (t2); break;
1069       case tcc_exceptional:
1070         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
1071       default: gcc_unreachable ();
1072       }
1073
1074   return t1 == t2;
1075 }
1076
1077 /* Allocate the seen two types, assuming that they are compatible. */
1078
1079 static struct tagged_tu_seen_cache *
1080 alloc_tagged_tu_seen_cache (const_tree t1, const_tree t2)
1081 {
1082   struct tagged_tu_seen_cache *tu = XNEW (struct tagged_tu_seen_cache);
1083   tu->next = tagged_tu_seen_base;
1084   tu->t1 = t1;
1085   tu->t2 = t2;
1086
1087   tagged_tu_seen_base = tu;
1088
1089   /* The C standard says that two structures in different translation
1090      units are compatible with each other only if the types of their
1091      fields are compatible (among other things).  We assume that they
1092      are compatible until proven otherwise when building the cache.
1093      An example where this can occur is:
1094      struct a
1095      {
1096        struct a *next;
1097      };
1098      If we are comparing this against a similar struct in another TU,
1099      and did not assume they were compatible, we end up with an infinite
1100      loop.  */
1101   tu->val = 1;
1102   return tu;
1103 }
1104
1105 /* Free the seen types until we get to TU_TIL. */
1106
1107 static void
1108 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
1109 {
1110   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
1111   while (tu != tu_til)
1112     {
1113       const struct tagged_tu_seen_cache *const tu1
1114         = (const struct tagged_tu_seen_cache *) tu;
1115       tu = tu1->next;
1116       free (CONST_CAST (tu1));
1117     }
1118   tagged_tu_seen_base = tu_til;
1119 }
1120
1121 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1122    compatible.  If the two types are not the same (which has been
1123    checked earlier), this can only happen when multiple translation
1124    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
1125    rules.  */
1126
1127 static int
1128 tagged_types_tu_compatible_p (const_tree t1, const_tree t2)
1129 {
1130   tree s1, s2;
1131   bool needs_warning = false;
1132
1133   /* We have to verify that the tags of the types are the same.  This
1134      is harder than it looks because this may be a typedef, so we have
1135      to go look at the original type.  It may even be a typedef of a
1136      typedef...
1137      In the case of compiler-created builtin structs the TYPE_DECL
1138      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
1139   while (TYPE_NAME (t1)
1140          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
1141          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
1142     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
1143
1144   while (TYPE_NAME (t2)
1145          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
1146          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
1147     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
1148
1149   /* C90 didn't have the requirement that the two tags be the same.  */
1150   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
1151     return 0;
1152
1153   /* C90 didn't say what happened if one or both of the types were
1154      incomplete; we choose to follow C99 rules here, which is that they
1155      are compatible.  */
1156   if (TYPE_SIZE (t1) == NULL
1157       || TYPE_SIZE (t2) == NULL)
1158     return 1;
1159
1160   {
1161     const struct tagged_tu_seen_cache * tts_i;
1162     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
1163       if (tts_i->t1 == t1 && tts_i->t2 == t2)
1164         return tts_i->val;
1165   }
1166
1167   switch (TREE_CODE (t1))
1168     {
1169     case ENUMERAL_TYPE:
1170       {
1171         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1172         /* Speed up the case where the type values are in the same order.  */
1173         tree tv1 = TYPE_VALUES (t1);
1174         tree tv2 = TYPE_VALUES (t2);
1175
1176         if (tv1 == tv2)
1177           {
1178             return 1;
1179           }
1180
1181         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1182           {
1183             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1184               break;
1185             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1186               {
1187                 tu->val = 0;
1188                 return 0;
1189               }
1190           }
1191
1192         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1193           {
1194             return 1;
1195           }
1196         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1197           {
1198             tu->val = 0;
1199             return 0;
1200           }
1201
1202         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1203           {
1204             tu->val = 0;
1205             return 0;
1206           }
1207
1208         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1209           {
1210             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1211             if (s2 == NULL
1212                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1213               {
1214                 tu->val = 0;
1215                 return 0;
1216               }
1217           }
1218         return 1;
1219       }
1220
1221     case UNION_TYPE:
1222       {
1223         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1224         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1225           {
1226             tu->val = 0;
1227             return 0;
1228           }
1229
1230         /*  Speed up the common case where the fields are in the same order. */
1231         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1232              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1233           {
1234             int result;
1235
1236
1237             if (DECL_NAME (s1) == NULL
1238                 || DECL_NAME (s1) != DECL_NAME (s2))
1239               break;
1240             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1241             if (result == 0)
1242               {
1243                 tu->val = 0;
1244                 return 0;
1245               }
1246             if (result == 2)
1247               needs_warning = true;
1248
1249             if (TREE_CODE (s1) == FIELD_DECL
1250                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1251                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1252               {
1253                 tu->val = 0;
1254                 return 0;
1255               }
1256           }
1257         if (!s1 && !s2)
1258           {
1259             tu->val = needs_warning ? 2 : 1;
1260             return tu->val;
1261           }
1262
1263         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1264           {
1265             bool ok = false;
1266
1267             if (DECL_NAME (s1) != NULL)
1268               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1269                 if (DECL_NAME (s1) == DECL_NAME (s2))
1270                   {
1271                     int result;
1272                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1273                     if (result == 0)
1274                       {
1275                         tu->val = 0;
1276                         return 0;
1277                       }
1278                     if (result == 2)
1279                       needs_warning = true;
1280
1281                     if (TREE_CODE (s1) == FIELD_DECL
1282                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1283                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1284                       break;
1285
1286                     ok = true;
1287                     break;
1288                   }
1289             if (!ok)
1290               {
1291                 tu->val = 0;
1292                 return 0;
1293               }
1294           }
1295         tu->val = needs_warning ? 2 : 10;
1296         return tu->val;
1297       }
1298
1299     case RECORD_TYPE:
1300       {
1301         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1302
1303         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1304              s1 && s2;
1305              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1306           {
1307             int result;
1308             if (TREE_CODE (s1) != TREE_CODE (s2)
1309                 || DECL_NAME (s1) != DECL_NAME (s2))
1310               break;
1311             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1312             if (result == 0)
1313               break;
1314             if (result == 2)
1315               needs_warning = true;
1316
1317             if (TREE_CODE (s1) == FIELD_DECL
1318                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1319                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1320               break;
1321           }
1322         if (s1 && s2)
1323           tu->val = 0;
1324         else
1325           tu->val = needs_warning ? 2 : 1;
1326         return tu->val;
1327       }
1328
1329     default:
1330       gcc_unreachable ();
1331     }
1332 }
1333
1334 /* Return 1 if two function types F1 and F2 are compatible.
1335    If either type specifies no argument types,
1336    the other must specify a fixed number of self-promoting arg types.
1337    Otherwise, if one type specifies only the number of arguments,
1338    the other must specify that number of self-promoting arg types.
1339    Otherwise, the argument types must match.  */
1340
1341 static int
1342 function_types_compatible_p (const_tree f1, const_tree f2)
1343 {
1344   tree args1, args2;
1345   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1346   int val = 1;
1347   int val1;
1348   tree ret1, ret2;
1349
1350   ret1 = TREE_TYPE (f1);
1351   ret2 = TREE_TYPE (f2);
1352
1353   /* 'volatile' qualifiers on a function's return type used to mean
1354      the function is noreturn.  */
1355   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1356     pedwarn ("function return types not compatible due to %<volatile%>");
1357   if (TYPE_VOLATILE (ret1))
1358     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1359                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1360   if (TYPE_VOLATILE (ret2))
1361     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1362                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1363   val = comptypes_internal (ret1, ret2);
1364   if (val == 0)
1365     return 0;
1366
1367   args1 = TYPE_ARG_TYPES (f1);
1368   args2 = TYPE_ARG_TYPES (f2);
1369
1370   /* An unspecified parmlist matches any specified parmlist
1371      whose argument types don't need default promotions.  */
1372
1373   if (args1 == 0)
1374     {
1375       if (!self_promoting_args_p (args2))
1376         return 0;
1377       /* If one of these types comes from a non-prototype fn definition,
1378          compare that with the other type's arglist.
1379          If they don't match, ask for a warning (but no error).  */
1380       if (TYPE_ACTUAL_ARG_TYPES (f1)
1381           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1382         val = 2;
1383       return val;
1384     }
1385   if (args2 == 0)
1386     {
1387       if (!self_promoting_args_p (args1))
1388         return 0;
1389       if (TYPE_ACTUAL_ARG_TYPES (f2)
1390           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1391         val = 2;
1392       return val;
1393     }
1394
1395   /* Both types have argument lists: compare them and propagate results.  */
1396   val1 = type_lists_compatible_p (args1, args2);
1397   return val1 != 1 ? val1 : val;
1398 }
1399
1400 /* Check two lists of types for compatibility,
1401    returning 0 for incompatible, 1 for compatible,
1402    or 2 for compatible with warning.  */
1403
1404 static int
1405 type_lists_compatible_p (const_tree args1, const_tree args2)
1406 {
1407   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1408   int val = 1;
1409   int newval = 0;
1410
1411   while (1)
1412     {
1413       tree a1, mv1, a2, mv2;
1414       if (args1 == 0 && args2 == 0)
1415         return val;
1416       /* If one list is shorter than the other,
1417          they fail to match.  */
1418       if (args1 == 0 || args2 == 0)
1419         return 0;
1420       mv1 = a1 = TREE_VALUE (args1);
1421       mv2 = a2 = TREE_VALUE (args2);
1422       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1423         mv1 = TYPE_MAIN_VARIANT (mv1);
1424       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1425         mv2 = TYPE_MAIN_VARIANT (mv2);
1426       /* A null pointer instead of a type
1427          means there is supposed to be an argument
1428          but nothing is specified about what type it has.
1429          So match anything that self-promotes.  */
1430       if (a1 == 0)
1431         {
1432           if (c_type_promotes_to (a2) != a2)
1433             return 0;
1434         }
1435       else if (a2 == 0)
1436         {
1437           if (c_type_promotes_to (a1) != a1)
1438             return 0;
1439         }
1440       /* If one of the lists has an error marker, ignore this arg.  */
1441       else if (TREE_CODE (a1) == ERROR_MARK
1442                || TREE_CODE (a2) == ERROR_MARK)
1443         ;
1444       else if (!(newval = comptypes_internal (mv1, mv2)))
1445         {
1446           /* Allow  wait (union {union wait *u; int *i} *)
1447              and  wait (union wait *)  to be compatible.  */
1448           if (TREE_CODE (a1) == UNION_TYPE
1449               && (TYPE_NAME (a1) == 0
1450                   || TYPE_TRANSPARENT_UNION (a1))
1451               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1452               && tree_int_cst_equal (TYPE_SIZE (a1),
1453                                      TYPE_SIZE (a2)))
1454             {
1455               tree memb;
1456               for (memb = TYPE_FIELDS (a1);
1457                    memb; memb = TREE_CHAIN (memb))
1458                 {
1459                   tree mv3 = TREE_TYPE (memb);
1460                   if (mv3 && mv3 != error_mark_node
1461                       && TREE_CODE (mv3) != ARRAY_TYPE)
1462                     mv3 = TYPE_MAIN_VARIANT (mv3);
1463                   if (comptypes_internal (mv3, mv2))
1464                     break;
1465                 }
1466               if (memb == 0)
1467                 return 0;
1468             }
1469           else if (TREE_CODE (a2) == UNION_TYPE
1470                    && (TYPE_NAME (a2) == 0
1471                        || TYPE_TRANSPARENT_UNION (a2))
1472                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1473                    && tree_int_cst_equal (TYPE_SIZE (a2),
1474                                           TYPE_SIZE (a1)))
1475             {
1476               tree memb;
1477               for (memb = TYPE_FIELDS (a2);
1478                    memb; memb = TREE_CHAIN (memb))
1479                 {
1480                   tree mv3 = TREE_TYPE (memb);
1481                   if (mv3 && mv3 != error_mark_node
1482                       && TREE_CODE (mv3) != ARRAY_TYPE)
1483                     mv3 = TYPE_MAIN_VARIANT (mv3);
1484                   if (comptypes_internal (mv3, mv1))
1485                     break;
1486                 }
1487               if (memb == 0)
1488                 return 0;
1489             }
1490           else
1491             return 0;
1492         }
1493
1494       /* comptypes said ok, but record if it said to warn.  */
1495       if (newval > val)
1496         val = newval;
1497
1498       args1 = TREE_CHAIN (args1);
1499       args2 = TREE_CHAIN (args2);
1500     }
1501 }
1502 \f
1503 /* Compute the size to increment a pointer by.  */
1504
1505 static tree
1506 c_size_in_bytes (const_tree type)
1507 {
1508   enum tree_code code = TREE_CODE (type);
1509
1510   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1511     return size_one_node;
1512
1513   if (!COMPLETE_OR_VOID_TYPE_P (type))
1514     {
1515       error ("arithmetic on pointer to an incomplete type");
1516       return size_one_node;
1517     }
1518
1519   /* Convert in case a char is more than one unit.  */
1520   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1521                      size_int (TYPE_PRECISION (char_type_node)
1522                                / BITS_PER_UNIT));
1523 }
1524 \f
1525 /* Return either DECL or its known constant value (if it has one).  */
1526
1527 tree
1528 decl_constant_value (tree decl)
1529 {
1530   if (/* Don't change a variable array bound or initial value to a constant
1531          in a place where a variable is invalid.  Note that DECL_INITIAL
1532          isn't valid for a PARM_DECL.  */
1533       current_function_decl != 0
1534       && TREE_CODE (decl) != PARM_DECL
1535       && !TREE_THIS_VOLATILE (decl)
1536       && TREE_READONLY (decl)
1537       && DECL_INITIAL (decl) != 0
1538       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1539       /* This is invalid if initial value is not constant.
1540          If it has either a function call, a memory reference,
1541          or a variable, then re-evaluating it could give different results.  */
1542       && TREE_CONSTANT (DECL_INITIAL (decl))
1543       /* Check for cases where this is sub-optimal, even though valid.  */
1544       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1545     return DECL_INITIAL (decl);
1546   return decl;
1547 }
1548
1549 /* Return either DECL or its known constant value (if it has one), but
1550    return DECL if pedantic or DECL has mode BLKmode.  This is for
1551    bug-compatibility with the old behavior of decl_constant_value
1552    (before GCC 3.0); every use of this function is a bug and it should
1553    be removed before GCC 3.1.  It is not appropriate to use pedantic
1554    in a way that affects optimization, and BLKmode is probably not the
1555    right test for avoiding misoptimizations either.  */
1556
1557 static tree
1558 decl_constant_value_for_broken_optimization (tree decl)
1559 {
1560   tree ret;
1561
1562   if (pedantic || DECL_MODE (decl) == BLKmode)
1563     return decl;
1564
1565   ret = decl_constant_value (decl);
1566   /* Avoid unwanted tree sharing between the initializer and current
1567      function's body where the tree can be modified e.g. by the
1568      gimplifier.  */
1569   if (ret != decl && TREE_STATIC (decl))
1570     ret = unshare_expr (ret);
1571   return ret;
1572 }
1573
1574 /* Convert the array expression EXP to a pointer.  */
1575 static tree
1576 array_to_pointer_conversion (tree exp)
1577 {
1578   tree orig_exp = exp;
1579   tree type = TREE_TYPE (exp);
1580   tree adr;
1581   tree restype = TREE_TYPE (type);
1582   tree ptrtype;
1583
1584   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1585
1586   STRIP_TYPE_NOPS (exp);
1587
1588   if (TREE_NO_WARNING (orig_exp))
1589     TREE_NO_WARNING (exp) = 1;
1590
1591   ptrtype = build_pointer_type (restype);
1592
1593   if (TREE_CODE (exp) == INDIRECT_REF)
1594     return convert (ptrtype, TREE_OPERAND (exp, 0));
1595
1596   if (TREE_CODE (exp) == VAR_DECL)
1597     {
1598       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1599          ADDR_EXPR because it's the best way of representing what
1600          happens in C when we take the address of an array and place
1601          it in a pointer to the element type.  */
1602       adr = build1 (ADDR_EXPR, ptrtype, exp);
1603       if (!c_mark_addressable (exp))
1604         return error_mark_node;
1605       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1606       return adr;
1607     }
1608
1609   /* This way is better for a COMPONENT_REF since it can
1610      simplify the offset for a component.  */
1611   adr = build_unary_op (ADDR_EXPR, exp, 1);
1612   return convert (ptrtype, adr);
1613 }
1614
1615 /* Convert the function expression EXP to a pointer.  */
1616 static tree
1617 function_to_pointer_conversion (tree exp)
1618 {
1619   tree orig_exp = exp;
1620
1621   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1622
1623   STRIP_TYPE_NOPS (exp);
1624
1625   if (TREE_NO_WARNING (orig_exp))
1626     TREE_NO_WARNING (exp) = 1;
1627
1628   return build_unary_op (ADDR_EXPR, exp, 0);
1629 }
1630
1631 /* Perform the default conversion of arrays and functions to pointers.
1632    Return the result of converting EXP.  For any other expression, just
1633    return EXP after removing NOPs.  */
1634
1635 struct c_expr
1636 default_function_array_conversion (struct c_expr exp)
1637 {
1638   tree orig_exp = exp.value;
1639   tree type = TREE_TYPE (exp.value);
1640   enum tree_code code = TREE_CODE (type);
1641
1642   switch (code)
1643     {
1644     case ARRAY_TYPE:
1645       {
1646         bool not_lvalue = false;
1647         bool lvalue_array_p;
1648
1649         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1650                 || TREE_CODE (exp.value) == NOP_EXPR
1651                 || TREE_CODE (exp.value) == CONVERT_EXPR)
1652                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1653           {
1654             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1655               not_lvalue = true;
1656             exp.value = TREE_OPERAND (exp.value, 0);
1657           }
1658
1659         if (TREE_NO_WARNING (orig_exp))
1660           TREE_NO_WARNING (exp.value) = 1;
1661
1662         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1663         if (!flag_isoc99 && !lvalue_array_p)
1664           {
1665             /* Before C99, non-lvalue arrays do not decay to pointers.
1666                Normally, using such an array would be invalid; but it can
1667                be used correctly inside sizeof or as a statement expression.
1668                Thus, do not give an error here; an error will result later.  */
1669             return exp;
1670           }
1671
1672         exp.value = array_to_pointer_conversion (exp.value);
1673       }
1674       break;
1675     case FUNCTION_TYPE:
1676       exp.value = function_to_pointer_conversion (exp.value);
1677       break;
1678     default:
1679       STRIP_TYPE_NOPS (exp.value);
1680       if (TREE_NO_WARNING (orig_exp))
1681         TREE_NO_WARNING (exp.value) = 1;
1682       break;
1683     }
1684
1685   return exp;
1686 }
1687
1688
1689 /* EXP is an expression of integer type.  Apply the integer promotions
1690    to it and return the promoted value.  */
1691
1692 tree
1693 perform_integral_promotions (tree exp)
1694 {
1695   tree type = TREE_TYPE (exp);
1696   enum tree_code code = TREE_CODE (type);
1697
1698   gcc_assert (INTEGRAL_TYPE_P (type));
1699
1700   /* Normally convert enums to int,
1701      but convert wide enums to something wider.  */
1702   if (code == ENUMERAL_TYPE)
1703     {
1704       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1705                                           TYPE_PRECISION (integer_type_node)),
1706                                      ((TYPE_PRECISION (type)
1707                                        >= TYPE_PRECISION (integer_type_node))
1708                                       && TYPE_UNSIGNED (type)));
1709
1710       return convert (type, exp);
1711     }
1712
1713   /* ??? This should no longer be needed now bit-fields have their
1714      proper types.  */
1715   if (TREE_CODE (exp) == COMPONENT_REF
1716       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1717       /* If it's thinner than an int, promote it like a
1718          c_promoting_integer_type_p, otherwise leave it alone.  */
1719       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1720                                TYPE_PRECISION (integer_type_node)))
1721     return convert (integer_type_node, exp);
1722
1723   if (c_promoting_integer_type_p (type))
1724     {
1725       /* Preserve unsignedness if not really getting any wider.  */
1726       if (TYPE_UNSIGNED (type)
1727           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1728         return convert (unsigned_type_node, exp);
1729
1730       return convert (integer_type_node, exp);
1731     }
1732
1733   return exp;
1734 }
1735
1736
1737 /* Perform default promotions for C data used in expressions.
1738    Enumeral types or short or char are converted to int.
1739    In addition, manifest constants symbols are replaced by their values.  */
1740
1741 tree
1742 default_conversion (tree exp)
1743 {
1744   tree orig_exp;
1745   tree type = TREE_TYPE (exp);
1746   enum tree_code code = TREE_CODE (type);
1747
1748   /* Functions and arrays have been converted during parsing.  */
1749   gcc_assert (code != FUNCTION_TYPE);
1750   if (code == ARRAY_TYPE)
1751     return exp;
1752
1753   /* Constants can be used directly unless they're not loadable.  */
1754   if (TREE_CODE (exp) == CONST_DECL)
1755     exp = DECL_INITIAL (exp);
1756
1757   /* Replace a nonvolatile const static variable with its value unless
1758      it is an array, in which case we must be sure that taking the
1759      address of the array produces consistent results.  */
1760   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1761     {
1762       exp = decl_constant_value_for_broken_optimization (exp);
1763       type = TREE_TYPE (exp);
1764     }
1765
1766   /* Strip no-op conversions.  */
1767   orig_exp = exp;
1768   STRIP_TYPE_NOPS (exp);
1769
1770   if (TREE_NO_WARNING (orig_exp))
1771     TREE_NO_WARNING (exp) = 1;
1772
1773   if (INTEGRAL_TYPE_P (type))
1774     return perform_integral_promotions (exp);
1775
1776   if (code == VOID_TYPE)
1777     {
1778       error ("void value not ignored as it ought to be");
1779       return error_mark_node;
1780     }
1781   return exp;
1782 }
1783 \f
1784 /* Look up COMPONENT in a structure or union DECL.
1785
1786    If the component name is not found, returns NULL_TREE.  Otherwise,
1787    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1788    stepping down the chain to the component, which is in the last
1789    TREE_VALUE of the list.  Normally the list is of length one, but if
1790    the component is embedded within (nested) anonymous structures or
1791    unions, the list steps down the chain to the component.  */
1792
1793 static tree
1794 lookup_field (tree decl, tree component)
1795 {
1796   tree type = TREE_TYPE (decl);
1797   tree field;
1798
1799   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1800      to the field elements.  Use a binary search on this array to quickly
1801      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1802      will always be set for structures which have many elements.  */
1803
1804   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1805     {
1806       int bot, top, half;
1807       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1808
1809       field = TYPE_FIELDS (type);
1810       bot = 0;
1811       top = TYPE_LANG_SPECIFIC (type)->s->len;
1812       while (top - bot > 1)
1813         {
1814           half = (top - bot + 1) >> 1;
1815           field = field_array[bot+half];
1816
1817           if (DECL_NAME (field) == NULL_TREE)
1818             {
1819               /* Step through all anon unions in linear fashion.  */
1820               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1821                 {
1822                   field = field_array[bot++];
1823                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1824                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1825                     {
1826                       tree anon = lookup_field (field, component);
1827
1828                       if (anon)
1829                         return tree_cons (NULL_TREE, field, anon);
1830                     }
1831                 }
1832
1833               /* Entire record is only anon unions.  */
1834               if (bot > top)
1835                 return NULL_TREE;
1836
1837               /* Restart the binary search, with new lower bound.  */
1838               continue;
1839             }
1840
1841           if (DECL_NAME (field) == component)
1842             break;
1843           if (DECL_NAME (field) < component)
1844             bot += half;
1845           else
1846             top = bot + half;
1847         }
1848
1849       if (DECL_NAME (field_array[bot]) == component)
1850         field = field_array[bot];
1851       else if (DECL_NAME (field) != component)
1852         return NULL_TREE;
1853     }
1854   else
1855     {
1856       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1857         {
1858           if (DECL_NAME (field) == NULL_TREE
1859               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1860                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1861             {
1862               tree anon = lookup_field (field, component);
1863
1864               if (anon)
1865                 return tree_cons (NULL_TREE, field, anon);
1866             }
1867
1868           if (DECL_NAME (field) == component)
1869             break;
1870         }
1871
1872       if (field == NULL_TREE)
1873         return NULL_TREE;
1874     }
1875
1876   return tree_cons (NULL_TREE, field, NULL_TREE);
1877 }
1878
1879 /* Make an expression to refer to the COMPONENT field of
1880    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1881
1882 tree
1883 build_component_ref (tree datum, tree component)
1884 {
1885   tree type = TREE_TYPE (datum);
1886   enum tree_code code = TREE_CODE (type);
1887   tree field = NULL;
1888   tree ref;
1889
1890   if (!objc_is_public (datum, component))
1891     return error_mark_node;
1892
1893   /* See if there is a field or component with name COMPONENT.  */
1894
1895   if (code == RECORD_TYPE || code == UNION_TYPE)
1896     {
1897       if (!COMPLETE_TYPE_P (type))
1898         {
1899           c_incomplete_type_error (NULL_TREE, type);
1900           return error_mark_node;
1901         }
1902
1903       field = lookup_field (datum, component);
1904
1905       if (!field)
1906         {
1907           error ("%qT has no member named %qE", type, component);
1908           return error_mark_node;
1909         }
1910
1911       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1912          This might be better solved in future the way the C++ front
1913          end does it - by giving the anonymous entities each a
1914          separate name and type, and then have build_component_ref
1915          recursively call itself.  We can't do that here.  */
1916       do
1917         {
1918           tree subdatum = TREE_VALUE (field);
1919           int quals;
1920           tree subtype;
1921
1922           if (TREE_TYPE (subdatum) == error_mark_node)
1923             return error_mark_node;
1924
1925           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1926           quals |= TYPE_QUALS (TREE_TYPE (datum));
1927           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1928
1929           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1930                         NULL_TREE);
1931           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1932             TREE_READONLY (ref) = 1;
1933           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1934             TREE_THIS_VOLATILE (ref) = 1;
1935
1936           if (TREE_DEPRECATED (subdatum))
1937             warn_deprecated_use (subdatum);
1938
1939           datum = ref;
1940
1941           field = TREE_CHAIN (field);
1942         }
1943       while (field);
1944
1945       return ref;
1946     }
1947   else if (code != ERROR_MARK)
1948     error ("request for member %qE in something not a structure or union",
1949            component);
1950
1951   return error_mark_node;
1952 }
1953 \f
1954 /* Given an expression PTR for a pointer, return an expression
1955    for the value pointed to.
1956    ERRORSTRING is the name of the operator to appear in error messages.  */
1957
1958 tree
1959 build_indirect_ref (tree ptr, const char *errorstring)
1960 {
1961   tree pointer = default_conversion (ptr);
1962   tree type = TREE_TYPE (pointer);
1963
1964   if (TREE_CODE (type) == POINTER_TYPE)
1965     {
1966       if (TREE_CODE (pointer) == CONVERT_EXPR
1967           || TREE_CODE (pointer) == NOP_EXPR
1968           || TREE_CODE (pointer) == VIEW_CONVERT_EXPR)
1969         {
1970           /* If a warning is issued, mark it to avoid duplicates from
1971              the backend.  This only needs to be done at
1972              warn_strict_aliasing > 2.  */
1973           if (warn_strict_aliasing > 2)
1974             if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (pointer, 0)),
1975                                          type, TREE_OPERAND (pointer, 0)))
1976               TREE_NO_WARNING (pointer) = 1;
1977         }
1978
1979       if (TREE_CODE (pointer) == ADDR_EXPR
1980           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1981               == TREE_TYPE (type)))
1982         return TREE_OPERAND (pointer, 0);
1983       else
1984         {
1985           tree t = TREE_TYPE (type);
1986           tree ref;
1987
1988           ref = build1 (INDIRECT_REF, t, pointer);
1989
1990           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1991             {
1992               error ("dereferencing pointer to incomplete type");
1993               return error_mark_node;
1994             }
1995           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1996             warning (0, "dereferencing %<void *%> pointer");
1997
1998           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1999              so that we get the proper error message if the result is used
2000              to assign to.  Also, &* is supposed to be a no-op.
2001              And ANSI C seems to specify that the type of the result
2002              should be the const type.  */
2003           /* A de-reference of a pointer to const is not a const.  It is valid
2004              to change it via some other pointer.  */
2005           TREE_READONLY (ref) = TYPE_READONLY (t);
2006           TREE_SIDE_EFFECTS (ref)
2007             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
2008           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
2009           return ref;
2010         }
2011     }
2012   else if (TREE_CODE (pointer) != ERROR_MARK)
2013     error ("invalid type argument of %qs (have %qT)", errorstring, type);
2014   return error_mark_node;
2015 }
2016
2017 /* This handles expressions of the form "a[i]", which denotes
2018    an array reference.
2019
2020    This is logically equivalent in C to *(a+i), but we may do it differently.
2021    If A is a variable or a member, we generate a primitive ARRAY_REF.
2022    This avoids forcing the array out of registers, and can work on
2023    arrays that are not lvalues (for example, members of structures returned
2024    by functions).  */
2025
2026 tree
2027 build_array_ref (tree array, tree index)
2028 {
2029   bool swapped = false;
2030   if (TREE_TYPE (array) == error_mark_node
2031       || TREE_TYPE (index) == error_mark_node)
2032     return error_mark_node;
2033
2034   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
2035       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
2036     {
2037       tree temp;
2038       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
2039           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
2040         {
2041           error ("subscripted value is neither array nor pointer");
2042           return error_mark_node;
2043         }
2044       temp = array;
2045       array = index;
2046       index = temp;
2047       swapped = true;
2048     }
2049
2050   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
2051     {
2052       error ("array subscript is not an integer");
2053       return error_mark_node;
2054     }
2055
2056   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
2057     {
2058       error ("subscripted value is pointer to function");
2059       return error_mark_node;
2060     }
2061
2062   /* ??? Existing practice has been to warn only when the char
2063      index is syntactically the index, not for char[array].  */
2064   if (!swapped)
2065      warn_array_subscript_with_type_char (index);
2066
2067   /* Apply default promotions *after* noticing character types.  */
2068   index = default_conversion (index);
2069
2070   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
2071
2072   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
2073     {
2074       tree rval, type;
2075
2076       /* An array that is indexed by a non-constant
2077          cannot be stored in a register; we must be able to do
2078          address arithmetic on its address.
2079          Likewise an array of elements of variable size.  */
2080       if (TREE_CODE (index) != INTEGER_CST
2081           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2082               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
2083         {
2084           if (!c_mark_addressable (array))
2085             return error_mark_node;
2086         }
2087       /* An array that is indexed by a constant value which is not within
2088          the array bounds cannot be stored in a register either; because we
2089          would get a crash in store_bit_field/extract_bit_field when trying
2090          to access a non-existent part of the register.  */
2091       if (TREE_CODE (index) == INTEGER_CST
2092           && TYPE_DOMAIN (TREE_TYPE (array))
2093           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
2094         {
2095           if (!c_mark_addressable (array))
2096             return error_mark_node;
2097         }
2098
2099       if (pedantic)
2100         {
2101           tree foo = array;
2102           while (TREE_CODE (foo) == COMPONENT_REF)
2103             foo = TREE_OPERAND (foo, 0);
2104           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
2105             pedwarn ("ISO C forbids subscripting %<register%> array");
2106           else if (!flag_isoc99 && !lvalue_p (foo))
2107             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
2108         }
2109
2110       type = TREE_TYPE (TREE_TYPE (array));
2111       if (TREE_CODE (type) != ARRAY_TYPE)
2112         type = TYPE_MAIN_VARIANT (type);
2113       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
2114       /* Array ref is const/volatile if the array elements are
2115          or if the array is.  */
2116       TREE_READONLY (rval)
2117         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
2118             | TREE_READONLY (array));
2119       TREE_SIDE_EFFECTS (rval)
2120         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2121             | TREE_SIDE_EFFECTS (array));
2122       TREE_THIS_VOLATILE (rval)
2123         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
2124             /* This was added by rms on 16 Nov 91.
2125                It fixes  vol struct foo *a;  a->elts[1]
2126                in an inline function.
2127                Hope it doesn't break something else.  */
2128             | TREE_THIS_VOLATILE (array));
2129       return require_complete_type (fold (rval));
2130     }
2131   else
2132     {
2133       tree ar = default_conversion (array);
2134
2135       if (ar == error_mark_node)
2136         return ar;
2137
2138       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
2139       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
2140
2141       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
2142                                  "array indexing");
2143     }
2144 }
2145 \f
2146 /* Build an external reference to identifier ID.  FUN indicates
2147    whether this will be used for a function call.  LOC is the source
2148    location of the identifier.  */
2149 tree
2150 build_external_ref (tree id, int fun, location_t loc)
2151 {
2152   tree ref;
2153   tree decl = lookup_name (id);
2154
2155   /* In Objective-C, an instance variable (ivar) may be preferred to
2156      whatever lookup_name() found.  */
2157   decl = objc_lookup_ivar (decl, id);
2158
2159   if (decl && decl != error_mark_node)
2160     ref = decl;
2161   else if (fun)
2162     /* Implicit function declaration.  */
2163     ref = implicitly_declare (id);
2164   else if (decl == error_mark_node)
2165     /* Don't complain about something that's already been
2166        complained about.  */
2167     return error_mark_node;
2168   else
2169     {
2170       undeclared_variable (id, loc);
2171       return error_mark_node;
2172     }
2173
2174   if (TREE_TYPE (ref) == error_mark_node)
2175     return error_mark_node;
2176
2177   if (TREE_DEPRECATED (ref))
2178     warn_deprecated_use (ref);
2179
2180   /* Recursive call does not count as usage.  */
2181   if (ref != current_function_decl)
2182     {
2183       if (!skip_evaluation)
2184         assemble_external (ref);
2185       TREE_USED (ref) = 1;
2186     }
2187
2188   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
2189     {
2190       if (!in_sizeof && !in_typeof)
2191         C_DECL_USED (ref) = 1;
2192       else if (DECL_INITIAL (ref) == 0
2193                && DECL_EXTERNAL (ref)
2194                && !TREE_PUBLIC (ref))
2195         record_maybe_used_decl (ref);
2196     }
2197
2198   if (TREE_CODE (ref) == CONST_DECL)
2199     {
2200       used_types_insert (TREE_TYPE (ref));
2201       ref = DECL_INITIAL (ref);
2202       TREE_CONSTANT (ref) = 1;
2203       TREE_INVARIANT (ref) = 1;
2204     }
2205   else if (current_function_decl != 0
2206            && !DECL_FILE_SCOPE_P (current_function_decl)
2207            && (TREE_CODE (ref) == VAR_DECL
2208                || TREE_CODE (ref) == PARM_DECL
2209                || TREE_CODE (ref) == FUNCTION_DECL))
2210     {
2211       tree context = decl_function_context (ref);
2212
2213       if (context != 0 && context != current_function_decl)
2214         DECL_NONLOCAL (ref) = 1;
2215     }
2216   /* C99 6.7.4p3: An inline definition of a function with external
2217      linkage ... shall not contain a reference to an identifier with
2218      internal linkage.  */
2219   else if (current_function_decl != 0
2220            && DECL_DECLARED_INLINE_P (current_function_decl)
2221            && DECL_EXTERNAL (current_function_decl)
2222            && VAR_OR_FUNCTION_DECL_P (ref)
2223            && (TREE_CODE (ref) != VAR_DECL || TREE_STATIC (ref))
2224            && ! TREE_PUBLIC (ref))
2225     pedwarn ("%H%qD is static but used in inline function %qD "
2226              "which is not static", &loc, ref, current_function_decl);
2227
2228   return ref;
2229 }
2230
2231 /* Record details of decls possibly used inside sizeof or typeof.  */
2232 struct maybe_used_decl
2233 {
2234   /* The decl.  */
2235   tree decl;
2236   /* The level seen at (in_sizeof + in_typeof).  */
2237   int level;
2238   /* The next one at this level or above, or NULL.  */
2239   struct maybe_used_decl *next;
2240 };
2241
2242 static struct maybe_used_decl *maybe_used_decls;
2243
2244 /* Record that DECL, an undefined static function reference seen
2245    inside sizeof or typeof, might be used if the operand of sizeof is
2246    a VLA type or the operand of typeof is a variably modified
2247    type.  */
2248
2249 static void
2250 record_maybe_used_decl (tree decl)
2251 {
2252   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2253   t->decl = decl;
2254   t->level = in_sizeof + in_typeof;
2255   t->next = maybe_used_decls;
2256   maybe_used_decls = t;
2257 }
2258
2259 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2260    USED is false, just discard them.  If it is true, mark them used
2261    (if no longer inside sizeof or typeof) or move them to the next
2262    level up (if still inside sizeof or typeof).  */
2263
2264 void
2265 pop_maybe_used (bool used)
2266 {
2267   struct maybe_used_decl *p = maybe_used_decls;
2268   int cur_level = in_sizeof + in_typeof;
2269   while (p && p->level > cur_level)
2270     {
2271       if (used)
2272         {
2273           if (cur_level == 0)
2274             C_DECL_USED (p->decl) = 1;
2275           else
2276             p->level = cur_level;
2277         }
2278       p = p->next;
2279     }
2280   if (!used || cur_level == 0)
2281     maybe_used_decls = p;
2282 }
2283
2284 /* Return the result of sizeof applied to EXPR.  */
2285
2286 struct c_expr
2287 c_expr_sizeof_expr (struct c_expr expr)
2288 {
2289   struct c_expr ret;
2290   if (expr.value == error_mark_node)
2291     {
2292       ret.value = error_mark_node;
2293       ret.original_code = ERROR_MARK;
2294       pop_maybe_used (false);
2295     }
2296   else
2297     {
2298       ret.value = c_sizeof (TREE_TYPE (expr.value));
2299       ret.original_code = ERROR_MARK;
2300       if (c_vla_type_p (TREE_TYPE (expr.value)))
2301         {
2302           /* sizeof is evaluated when given a vla (C99 6.5.3.4p2).  */
2303           ret.value = build2 (COMPOUND_EXPR, TREE_TYPE (ret.value), expr.value, ret.value);
2304         }
2305       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2306     }
2307   return ret;
2308 }
2309
2310 /* Return the result of sizeof applied to T, a structure for the type
2311    name passed to sizeof (rather than the type itself).  */
2312
2313 struct c_expr
2314 c_expr_sizeof_type (struct c_type_name *t)
2315 {
2316   tree type;
2317   struct c_expr ret;
2318   type = groktypename (t);
2319   ret.value = c_sizeof (type);
2320   ret.original_code = ERROR_MARK;
2321   pop_maybe_used (type != error_mark_node
2322                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2323   return ret;
2324 }
2325
2326 /* Build a function call to function FUNCTION with parameters PARAMS.
2327    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2328    TREE_VALUE of each node is a parameter-expression.
2329    FUNCTION's data type may be a function type or a pointer-to-function.  */
2330
2331 tree
2332 build_function_call (tree function, tree params)
2333 {
2334   tree fntype, fundecl = 0;
2335   tree name = NULL_TREE, result;
2336   tree tem;
2337   int nargs;
2338   tree *argarray;
2339
2340
2341   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2342   STRIP_TYPE_NOPS (function);
2343
2344   /* Convert anything with function type to a pointer-to-function.  */
2345   if (TREE_CODE (function) == FUNCTION_DECL)
2346     {
2347       /* Implement type-directed function overloading for builtins.
2348          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2349          handle all the type checking.  The result is a complete expression
2350          that implements this function call.  */
2351       tem = resolve_overloaded_builtin (function, params);
2352       if (tem)
2353         return tem;
2354
2355       name = DECL_NAME (function);
2356       fundecl = function;
2357     }
2358   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2359     function = function_to_pointer_conversion (function);
2360
2361   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2362      expressions, like those used for ObjC messenger dispatches.  */
2363   function = objc_rewrite_function_call (function, params);
2364
2365   fntype = TREE_TYPE (function);
2366
2367   if (TREE_CODE (fntype) == ERROR_MARK)
2368     return error_mark_node;
2369
2370   if (!(TREE_CODE (fntype) == POINTER_TYPE
2371         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2372     {
2373       error ("called object %qE is not a function", function);
2374       return error_mark_node;
2375     }
2376
2377   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2378     current_function_returns_abnormally = 1;
2379
2380   /* fntype now gets the type of function pointed to.  */
2381   fntype = TREE_TYPE (fntype);
2382
2383   /* Check that the function is called through a compatible prototype.
2384      If it is not, replace the call by a trap, wrapped up in a compound
2385      expression if necessary.  This has the nice side-effect to prevent
2386      the tree-inliner from generating invalid assignment trees which may
2387      blow up in the RTL expander later.  */
2388   if ((TREE_CODE (function) == NOP_EXPR
2389        || TREE_CODE (function) == CONVERT_EXPR)
2390       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2391       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2392       && !comptypes (fntype, TREE_TYPE (tem)))
2393     {
2394       tree return_type = TREE_TYPE (fntype);
2395       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2396                                        NULL_TREE);
2397
2398       /* This situation leads to run-time undefined behavior.  We can't,
2399          therefore, simply error unless we can prove that all possible
2400          executions of the program must execute the code.  */
2401       warning (0, "function called through a non-compatible type");
2402
2403       /* We can, however, treat "undefined" any way we please.
2404          Call abort to encourage the user to fix the program.  */
2405       inform ("if this code is reached, the program will abort");
2406
2407       if (VOID_TYPE_P (return_type))
2408         return trap;
2409       else
2410         {
2411           tree rhs;
2412
2413           if (AGGREGATE_TYPE_P (return_type))
2414             rhs = build_compound_literal (return_type,
2415                                           build_constructor (return_type, 0));
2416           else
2417             rhs = fold_convert (return_type, integer_zero_node);
2418
2419           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2420         }
2421     }
2422
2423   /* Convert the parameters to the types declared in the
2424      function prototype, or apply default promotions.  */
2425
2426   nargs = list_length (params);
2427   argarray = (tree *) alloca (nargs * sizeof (tree));
2428   nargs = convert_arguments (nargs, argarray, TYPE_ARG_TYPES (fntype),
2429                              params, function, fundecl);
2430   if (nargs < 0)
2431     return error_mark_node;
2432
2433   /* Check that the arguments to the function are valid.  */
2434
2435   check_function_arguments (TYPE_ATTRIBUTES (fntype), nargs, argarray,
2436                             TYPE_ARG_TYPES (fntype));
2437
2438   if (require_constant_value)
2439     {
2440       result = fold_build_call_array_initializer (TREE_TYPE (fntype),
2441                                                   function, nargs, argarray);
2442       if (TREE_CONSTANT (result)
2443           && (name == NULL_TREE
2444               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2445         pedwarn_init ("initializer element is not constant");
2446     }
2447   else
2448     result = fold_build_call_array (TREE_TYPE (fntype),
2449                                     function, nargs, argarray);
2450
2451   if (VOID_TYPE_P (TREE_TYPE (result)))
2452     return result;
2453   return require_complete_type (result);
2454 }
2455 \f
2456 /* Convert the argument expressions in the list VALUES
2457    to the types in the list TYPELIST.  The resulting arguments are
2458    stored in the array ARGARRAY which has size NARGS.
2459
2460    If TYPELIST is exhausted, or when an element has NULL as its type,
2461    perform the default conversions.
2462
2463    PARMLIST is the chain of parm decls for the function being called.
2464    It may be 0, if that info is not available.
2465    It is used only for generating error messages.
2466
2467    FUNCTION is a tree for the called function.  It is used only for
2468    error messages, where it is formatted with %qE.
2469
2470    This is also where warnings about wrong number of args are generated.
2471
2472    VALUES is a chain of TREE_LIST nodes with the elements of the list
2473    in the TREE_VALUE slots of those nodes.
2474
2475    Returns the actual number of arguments processed (which may be less
2476    than NARGS in some error situations), or -1 on failure.  */
2477
2478 static int
2479 convert_arguments (int nargs, tree *argarray,
2480                    tree typelist, tree values, tree function, tree fundecl)
2481 {
2482   tree typetail, valtail;
2483   int parmnum;
2484   const bool type_generic = fundecl
2485     && lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
2486   tree selector;
2487
2488   /* Change pointer to function to the function itself for
2489      diagnostics.  */
2490   if (TREE_CODE (function) == ADDR_EXPR
2491       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2492     function = TREE_OPERAND (function, 0);
2493
2494   /* Handle an ObjC selector specially for diagnostics.  */
2495   selector = objc_message_selector ();
2496
2497   /* Scan the given expressions and types, producing individual
2498      converted arguments and storing them in ARGARRAY.  */
2499
2500   for (valtail = values, typetail = typelist, parmnum = 0;
2501        valtail;
2502        valtail = TREE_CHAIN (valtail), parmnum++)
2503     {
2504       tree type = typetail ? TREE_VALUE (typetail) : 0;
2505       tree val = TREE_VALUE (valtail);
2506       tree rname = function;
2507       int argnum = parmnum + 1;
2508       const char *invalid_func_diag;
2509
2510       if (type == void_type_node)
2511         {
2512           error ("too many arguments to function %qE", function);
2513           return parmnum;
2514         }
2515
2516       if (selector && argnum > 2)
2517         {
2518           rname = selector;
2519           argnum -= 2;
2520         }
2521
2522       STRIP_TYPE_NOPS (val);
2523
2524       val = require_complete_type (val);
2525
2526       if (type != 0)
2527         {
2528           /* Formal parm type is specified by a function prototype.  */
2529           tree parmval;
2530
2531           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2532             {
2533               error ("type of formal parameter %d is incomplete", parmnum + 1);
2534               parmval = val;
2535             }
2536           else
2537             {
2538               /* Optionally warn about conversions that
2539                  differ from the default conversions.  */
2540               if (warn_traditional_conversion || warn_traditional)
2541                 {
2542                   unsigned int formal_prec = TYPE_PRECISION (type);
2543
2544                   if (INTEGRAL_TYPE_P (type)
2545                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2546                     warning (0, "passing argument %d of %qE as integer "
2547                              "rather than floating due to prototype",
2548                              argnum, rname);
2549                   if (INTEGRAL_TYPE_P (type)
2550                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2551                     warning (0, "passing argument %d of %qE as integer "
2552                              "rather than complex due to prototype",
2553                              argnum, rname);
2554                   else if (TREE_CODE (type) == COMPLEX_TYPE
2555                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2556                     warning (0, "passing argument %d of %qE as complex "
2557                              "rather than floating due to prototype",
2558                              argnum, rname);
2559                   else if (TREE_CODE (type) == REAL_TYPE
2560                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2561                     warning (0, "passing argument %d of %qE as floating "
2562                              "rather than integer due to prototype",
2563                              argnum, rname);
2564                   else if (TREE_CODE (type) == COMPLEX_TYPE
2565                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2566                     warning (0, "passing argument %d of %qE as complex "
2567                              "rather than integer due to prototype",
2568                              argnum, rname);
2569                   else if (TREE_CODE (type) == REAL_TYPE
2570                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2571                     warning (0, "passing argument %d of %qE as floating "
2572                              "rather than complex due to prototype",
2573                              argnum, rname);
2574                   /* ??? At some point, messages should be written about
2575                      conversions between complex types, but that's too messy
2576                      to do now.  */
2577                   else if (TREE_CODE (type) == REAL_TYPE
2578                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2579                     {
2580                       /* Warn if any argument is passed as `float',
2581                          since without a prototype it would be `double'.  */
2582                       if (formal_prec == TYPE_PRECISION (float_type_node)
2583                           && type != dfloat32_type_node)
2584                         warning (0, "passing argument %d of %qE as %<float%> "
2585                                  "rather than %<double%> due to prototype",
2586                                  argnum, rname);
2587
2588                       /* Warn if mismatch between argument and prototype
2589                          for decimal float types.  Warn of conversions with
2590                          binary float types and of precision narrowing due to
2591                          prototype. */
2592                       else if (type != TREE_TYPE (val)
2593                                && (type == dfloat32_type_node
2594                                    || type == dfloat64_type_node
2595                                    || type == dfloat128_type_node
2596                                    || TREE_TYPE (val) == dfloat32_type_node
2597                                    || TREE_TYPE (val) == dfloat64_type_node
2598                                    || TREE_TYPE (val) == dfloat128_type_node)
2599                                && (formal_prec
2600                                    <= TYPE_PRECISION (TREE_TYPE (val))
2601                                    || (type == dfloat128_type_node
2602                                        && (TREE_TYPE (val)
2603                                            != dfloat64_type_node
2604                                            && (TREE_TYPE (val)
2605                                                != dfloat32_type_node)))
2606                                    || (type == dfloat64_type_node
2607                                        && (TREE_TYPE (val)
2608                                            != dfloat32_type_node))))
2609                         warning (0, "passing argument %d of %qE as %qT "
2610                                  "rather than %qT due to prototype",
2611                                  argnum, rname, type, TREE_TYPE (val));
2612
2613                     }
2614                   /* Detect integer changing in width or signedness.
2615                      These warnings are only activated with
2616                      -Wtraditional-conversion, not with -Wtraditional.  */
2617                   else if (warn_traditional_conversion && INTEGRAL_TYPE_P (type)
2618                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2619                     {
2620                       tree would_have_been = default_conversion (val);
2621                       tree type1 = TREE_TYPE (would_have_been);
2622
2623                       if (TREE_CODE (type) == ENUMERAL_TYPE
2624                           && (TYPE_MAIN_VARIANT (type)
2625                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2626                         /* No warning if function asks for enum
2627                            and the actual arg is that enum type.  */
2628                         ;
2629                       else if (formal_prec != TYPE_PRECISION (type1))
2630                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2631                                  "with different width due to prototype",
2632                                  argnum, rname);
2633                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2634                         ;
2635                       /* Don't complain if the formal parameter type
2636                          is an enum, because we can't tell now whether
2637                          the value was an enum--even the same enum.  */
2638                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2639                         ;
2640                       else if (TREE_CODE (val) == INTEGER_CST
2641                                && int_fits_type_p (val, type))
2642                         /* Change in signedness doesn't matter
2643                            if a constant value is unaffected.  */
2644                         ;
2645                       /* If the value is extended from a narrower
2646                          unsigned type, it doesn't matter whether we
2647                          pass it as signed or unsigned; the value
2648                          certainly is the same either way.  */
2649                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2650                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2651                         ;
2652                       else if (TYPE_UNSIGNED (type))
2653                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2654                                  "as unsigned due to prototype",
2655                                  argnum, rname);
2656                       else
2657                         warning (OPT_Wtraditional_conversion, "passing argument %d of %qE "
2658                                  "as signed due to prototype", argnum, rname);
2659                     }
2660                 }
2661
2662               parmval = convert_for_assignment (type, val, ic_argpass,
2663                                                 fundecl, function,
2664                                                 parmnum + 1);
2665
2666               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2667                   && INTEGRAL_TYPE_P (type)
2668                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2669                 parmval = default_conversion (parmval);
2670             }
2671           argarray[parmnum] = parmval;
2672         }
2673       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2674                && (TYPE_PRECISION (TREE_TYPE (val))
2675                    < TYPE_PRECISION (double_type_node))
2676                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
2677         {
2678           if (type_generic)
2679             argarray[parmnum] = val;
2680           else
2681             /* Convert `float' to `double'.  */
2682             argarray[parmnum] = convert (double_type_node, val);
2683         }
2684       else if ((invalid_func_diag =
2685                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2686         {
2687           error (invalid_func_diag);
2688           return -1;
2689         }
2690       else
2691         /* Convert `short' and `char' to full-size `int'.  */
2692         argarray[parmnum] = default_conversion (val);
2693
2694       if (typetail)
2695         typetail = TREE_CHAIN (typetail);
2696     }
2697
2698   gcc_assert (parmnum == nargs);
2699
2700   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2701     {
2702       error ("too few arguments to function %qE", function);
2703       return -1;
2704     }
2705
2706   return parmnum;
2707 }
2708 \f
2709 /* This is the entry point used by the parser to build unary operators
2710    in the input.  CODE, a tree_code, specifies the unary operator, and
2711    ARG is the operand.  For unary plus, the C parser currently uses
2712    CONVERT_EXPR for code.  */
2713
2714 struct c_expr
2715 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2716 {
2717   struct c_expr result;
2718
2719   result.original_code = ERROR_MARK;
2720   result.value = build_unary_op (code, arg.value, 0);
2721
2722   if (TREE_OVERFLOW_P (result.value) && !TREE_OVERFLOW_P (arg.value))
2723     overflow_warning (result.value);
2724
2725   return result;
2726 }
2727
2728 /* This is the entry point used by the parser to build binary operators
2729    in the input.  CODE, a tree_code, specifies the binary operator, and
2730    ARG1 and ARG2 are the operands.  In addition to constructing the
2731    expression, we check for operands that were written with other binary
2732    operators in a way that is likely to confuse the user.  */
2733
2734 struct c_expr
2735 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2736                         struct c_expr arg2)
2737 {
2738   struct c_expr result;
2739
2740   enum tree_code code1 = arg1.original_code;
2741   enum tree_code code2 = arg2.original_code;
2742
2743   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2744   result.original_code = code;
2745
2746   if (TREE_CODE (result.value) == ERROR_MARK)
2747     return result;
2748
2749   /* Check for cases such as x+y<<z which users are likely
2750      to misinterpret.  */
2751   if (warn_parentheses)
2752     warn_about_parentheses (code, code1, code2);
2753
2754   if (code1 != tcc_comparison)
2755     warn_logical_operator (code, arg1.value, arg2.value);
2756
2757   /* Warn about comparisons against string literals, with the exception
2758      of testing for equality or inequality of a string literal with NULL.  */
2759   if (code == EQ_EXPR || code == NE_EXPR)
2760     {
2761       if ((code1 == STRING_CST && !integer_zerop (arg2.value))
2762           || (code2 == STRING_CST && !integer_zerop (arg1.value)))
2763         warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2764     }
2765   else if (TREE_CODE_CLASS (code) == tcc_comparison
2766            && (code1 == STRING_CST || code2 == STRING_CST))
2767     warning (OPT_Waddress, "comparison with string literal results in unspecified behavior");
2768
2769   if (TREE_OVERFLOW_P (result.value)
2770       && !TREE_OVERFLOW_P (arg1.value)
2771       && !TREE_OVERFLOW_P (arg2.value))
2772     overflow_warning (result.value);
2773
2774   return result;
2775 }
2776 \f
2777 /* Return a tree for the difference of pointers OP0 and OP1.
2778    The resulting tree has type int.  */
2779
2780 static tree
2781 pointer_diff (tree op0, tree op1)
2782 {
2783   tree restype = ptrdiff_type_node;
2784
2785   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2786   tree con0, con1, lit0, lit1;
2787   tree orig_op1 = op1;
2788
2789   if (pedantic || warn_pointer_arith)
2790     {
2791       if (TREE_CODE (target_type) == VOID_TYPE)
2792         pedwarn ("pointer of type %<void *%> used in subtraction");
2793       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2794         pedwarn ("pointer to a function used in subtraction");
2795     }
2796
2797   /* If the conversion to ptrdiff_type does anything like widening or
2798      converting a partial to an integral mode, we get a convert_expression
2799      that is in the way to do any simplifications.
2800      (fold-const.c doesn't know that the extra bits won't be needed.
2801      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2802      different mode in place.)
2803      So first try to find a common term here 'by hand'; we want to cover
2804      at least the cases that occur in legal static initializers.  */
2805   if ((TREE_CODE (op0) == NOP_EXPR || TREE_CODE (op0) == CONVERT_EXPR)
2806       && (TYPE_PRECISION (TREE_TYPE (op0))
2807           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
2808     con0 = TREE_OPERAND (op0, 0);
2809   else
2810     con0 = op0;
2811   if ((TREE_CODE (op1) == NOP_EXPR || TREE_CODE (op1) == CONVERT_EXPR)
2812       && (TYPE_PRECISION (TREE_TYPE (op1))
2813           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
2814     con1 = TREE_OPERAND (op1, 0);
2815   else
2816     con1 = op1;
2817
2818   if (TREE_CODE (con0) == PLUS_EXPR)
2819     {
2820       lit0 = TREE_OPERAND (con0, 1);
2821       con0 = TREE_OPERAND (con0, 0);
2822     }
2823   else
2824     lit0 = integer_zero_node;
2825
2826   if (TREE_CODE (con1) == PLUS_EXPR)
2827     {
2828       lit1 = TREE_OPERAND (con1, 1);
2829       con1 = TREE_OPERAND (con1, 0);
2830     }
2831   else
2832     lit1 = integer_zero_node;
2833
2834   if (operand_equal_p (con0, con1, 0))
2835     {
2836       op0 = lit0;
2837       op1 = lit1;
2838     }
2839
2840
2841   /* First do the subtraction as integers;
2842      then drop through to build the divide operator.
2843      Do not do default conversions on the minus operator
2844      in case restype is a short type.  */
2845
2846   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2847                          convert (restype, op1), 0);
2848   /* This generates an error if op1 is pointer to incomplete type.  */
2849   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2850     error ("arithmetic on pointer to an incomplete type");
2851
2852   /* This generates an error if op0 is pointer to incomplete type.  */
2853   op1 = c_size_in_bytes (target_type);
2854
2855   /* Divide by the size, in easiest possible way.  */
2856   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2857 }
2858 \f
2859 /* Construct and perhaps optimize a tree representation
2860    for a unary operation.  CODE, a tree_code, specifies the operation
2861    and XARG is the operand.
2862    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2863    the default promotions (such as from short to int).
2864    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2865    allows non-lvalues; this is only used to handle conversion of non-lvalue
2866    arrays to pointers in C99.  */
2867
2868 tree
2869 build_unary_op (enum tree_code code, tree xarg, int flag)
2870 {
2871   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2872   tree arg = xarg;
2873   tree argtype = 0;
2874   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2875   tree val;
2876   int noconvert = flag;
2877   const char *invalid_op_diag;
2878
2879   if (typecode == ERROR_MARK)
2880     return error_mark_node;
2881   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2882     typecode = INTEGER_TYPE;
2883
2884   if ((invalid_op_diag
2885        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2886     {
2887       error (invalid_op_diag);
2888       return error_mark_node;
2889     }
2890
2891   switch (code)
2892     {
2893     case CONVERT_EXPR:
2894       /* This is used for unary plus, because a CONVERT_EXPR
2895          is enough to prevent anybody from looking inside for
2896          associativity, but won't generate any code.  */
2897       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2898             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2899             || typecode == VECTOR_TYPE))
2900         {
2901           error ("wrong type argument to unary plus");
2902           return error_mark_node;
2903         }
2904       else if (!noconvert)
2905         arg = default_conversion (arg);
2906       arg = non_lvalue (arg);
2907       break;
2908
2909     case NEGATE_EXPR:
2910       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2911             || typecode == FIXED_POINT_TYPE || typecode == COMPLEX_TYPE
2912             || typecode == VECTOR_TYPE))
2913         {
2914           error ("wrong type argument to unary minus");
2915           return error_mark_node;
2916         }
2917       else if (!noconvert)
2918         arg = default_conversion (arg);
2919       break;
2920
2921     case BIT_NOT_EXPR:
2922       /* ~ works on integer types and non float vectors. */
2923       if (typecode == INTEGER_TYPE
2924           || (typecode == VECTOR_TYPE
2925               && !VECTOR_FLOAT_TYPE_P (TREE_TYPE (arg))))
2926         {
2927           if (!noconvert)
2928             arg = default_conversion (arg);
2929         }
2930       else if (typecode == COMPLEX_TYPE)
2931         {
2932           code = CONJ_EXPR;
2933           if (pedantic)
2934             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2935           if (!noconvert)
2936             arg = default_conversion (arg);
2937         }
2938       else
2939         {
2940           error ("wrong type argument to bit-complement");
2941           return error_mark_node;
2942         }
2943       break;
2944
2945     case ABS_EXPR:
2946       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2947         {
2948           error ("wrong type argument to abs");
2949           return error_mark_node;
2950         }
2951       else if (!noconvert)
2952         arg = default_conversion (arg);
2953       break;
2954
2955     case CONJ_EXPR:
2956       /* Conjugating a real value is a no-op, but allow it anyway.  */
2957       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2958             || typecode == COMPLEX_TYPE))
2959         {
2960           error ("wrong type argument to conjugation");
2961           return error_mark_node;
2962         }
2963       else if (!noconvert)
2964         arg = default_conversion (arg);
2965       break;
2966
2967     case TRUTH_NOT_EXPR:
2968       if (typecode != INTEGER_TYPE && typecode != FIXED_POINT_TYPE
2969           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2970           && typecode != COMPLEX_TYPE)
2971         {
2972           error ("wrong type argument to unary exclamation mark");
2973           return error_mark_node;
2974         }
2975       arg = c_objc_common_truthvalue_conversion (arg);
2976       return invert_truthvalue (arg);
2977
2978     case REALPART_EXPR:
2979       if (TREE_CODE (arg) == COMPLEX_CST)
2980         return TREE_REALPART (arg);
2981       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2982         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2983       else
2984         return arg;
2985
2986     case IMAGPART_EXPR:
2987       if (TREE_CODE (arg) == COMPLEX_CST)
2988         return TREE_IMAGPART (arg);
2989       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2990         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2991       else
2992         return convert (TREE_TYPE (arg), integer_zero_node);
2993
2994     case PREINCREMENT_EXPR:
2995     case POSTINCREMENT_EXPR:
2996     case PREDECREMENT_EXPR:
2997     case POSTDECREMENT_EXPR:
2998
2999       /* Increment or decrement the real part of the value,
3000          and don't change the imaginary part.  */
3001       if (typecode == COMPLEX_TYPE)
3002         {
3003           tree real, imag;
3004
3005           if (pedantic)
3006             pedwarn ("ISO C does not support %<++%> and %<--%>"
3007                      " on complex types");
3008
3009           arg = stabilize_reference (arg);
3010           real = build_unary_op (REALPART_EXPR, arg, 1);
3011           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3012           real = build_unary_op (code, real, 1);
3013           if (real == error_mark_node || imag == error_mark_node)
3014             return error_mark_node;
3015           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
3016                          real, imag);
3017         }
3018
3019       /* Report invalid types.  */
3020
3021       if (typecode != POINTER_TYPE && typecode != FIXED_POINT_TYPE
3022           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
3023         {
3024           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3025             error ("wrong type argument to increment");
3026           else
3027             error ("wrong type argument to decrement");
3028
3029           return error_mark_node;
3030         }
3031
3032       {
3033         tree inc;
3034         tree result_type = TREE_TYPE (arg);
3035
3036         arg = get_unwidened (arg, 0);
3037         argtype = TREE_TYPE (arg);
3038
3039         /* Compute the increment.  */
3040
3041         if (typecode == POINTER_TYPE)
3042           {
3043             /* If pointer target is an undefined struct,
3044                we just cannot know how to do the arithmetic.  */
3045             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
3046               {
3047                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3048                   error ("increment of pointer to unknown structure");
3049                 else
3050                   error ("decrement of pointer to unknown structure");
3051               }
3052             else if ((pedantic || warn_pointer_arith)
3053                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
3054                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
3055               {
3056                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3057                   pedwarn ("wrong type argument to increment");
3058                 else
3059                   pedwarn ("wrong type argument to decrement");
3060               }
3061
3062             inc = c_size_in_bytes (TREE_TYPE (result_type));
3063             inc = fold_convert (sizetype, inc);
3064           }
3065         else if (FRACT_MODE_P (TYPE_MODE (result_type)))
3066           {
3067             /* For signed fract types, we invert ++ to -- or
3068                -- to ++, and change inc from 1 to -1, because
3069                it is not possible to represent 1 in signed fract constants.
3070                For unsigned fract types, the result always overflows and
3071                we get an undefined (original) or the maximum value.  */
3072             if (code == PREINCREMENT_EXPR)
3073               code = PREDECREMENT_EXPR;
3074             else if (code == PREDECREMENT_EXPR)
3075               code = PREINCREMENT_EXPR;
3076             else if (code == POSTINCREMENT_EXPR)
3077               code = POSTDECREMENT_EXPR;
3078             else /* code == POSTDECREMENT_EXPR  */
3079               code = POSTINCREMENT_EXPR;
3080
3081             inc = integer_minus_one_node;
3082             inc = convert (argtype, inc);
3083           }
3084         else
3085           {
3086             inc = integer_one_node;
3087             inc = convert (argtype, inc);
3088           }
3089
3090         /* Complain about anything else that is not a true lvalue.  */
3091         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3092                                     || code == POSTINCREMENT_EXPR)
3093                                    ? lv_increment
3094                                    : lv_decrement)))
3095           return error_mark_node;
3096
3097         /* Report a read-only lvalue.  */
3098         if (TREE_READONLY (arg))
3099           {
3100             readonly_error (arg,
3101                             ((code == PREINCREMENT_EXPR
3102                               || code == POSTINCREMENT_EXPR)
3103                              ? lv_increment : lv_decrement));
3104             return error_mark_node;
3105           }
3106
3107         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3108           val = boolean_increment (code, arg);
3109         else
3110           val = build2 (code, TREE_TYPE (arg), arg, inc);
3111         TREE_SIDE_EFFECTS (val) = 1;
3112         val = convert (result_type, val);
3113         if (TREE_CODE (val) != code)
3114           TREE_NO_WARNING (val) = 1;
3115         return val;
3116       }
3117
3118     case ADDR_EXPR:
3119       /* Note that this operation never does default_conversion.  */
3120
3121       /* Let &* cancel out to simplify resulting code.  */
3122       if (TREE_CODE (arg) == INDIRECT_REF)
3123         {
3124           /* Don't let this be an lvalue.  */
3125           if (lvalue_p (TREE_OPERAND (arg, 0)))
3126             return non_lvalue (TREE_OPERAND (arg, 0));
3127           return TREE_OPERAND (arg, 0);
3128         }
3129
3130       /* For &x[y], return x+y */
3131       if (TREE_CODE (arg) == ARRAY_REF)
3132         {
3133           tree op0 = TREE_OPERAND (arg, 0);
3134           if (!c_mark_addressable (op0))
3135             return error_mark_node;
3136           return build_binary_op (PLUS_EXPR,
3137                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
3138                                    ? array_to_pointer_conversion (op0)
3139                                    : op0),
3140                                   TREE_OPERAND (arg, 1), 1);
3141         }
3142
3143       /* Anything not already handled and not a true memory reference
3144          or a non-lvalue array is an error.  */
3145       else if (typecode != FUNCTION_TYPE && !flag
3146                && !lvalue_or_else (arg, lv_addressof))
3147         return error_mark_node;
3148
3149       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
3150       argtype = TREE_TYPE (arg);
3151
3152       /* If the lvalue is const or volatile, merge that into the type
3153          to which the address will point.  Note that you can't get a
3154          restricted pointer by taking the address of something, so we
3155          only have to deal with `const' and `volatile' here.  */
3156       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
3157           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
3158           argtype = c_build_type_variant (argtype,
3159                                           TREE_READONLY (arg),
3160                                           TREE_THIS_VOLATILE (arg));
3161
3162       if (!c_mark_addressable (arg))
3163         return error_mark_node;
3164
3165       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
3166                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
3167
3168       argtype = build_pointer_type (argtype);
3169
3170       /* ??? Cope with user tricks that amount to offsetof.  Delete this
3171          when we have proper support for integer constant expressions.  */
3172       val = get_base_address (arg);
3173       if (val && TREE_CODE (val) == INDIRECT_REF
3174           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
3175         {
3176           tree op0 = fold_convert (sizetype, fold_offsetof (arg, val)), op1;
3177
3178           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
3179           return fold_build2 (POINTER_PLUS_EXPR, argtype, op1, op0);
3180         }
3181
3182       val = build1 (ADDR_EXPR, argtype, arg);
3183
3184       return val;
3185
3186     default:
3187       gcc_unreachable ();
3188     }
3189
3190   if (argtype == 0)
3191     argtype = TREE_TYPE (arg);
3192   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
3193                                 : fold_build1 (code, argtype, arg);
3194 }
3195
3196 /* Return nonzero if REF is an lvalue valid for this language.
3197    Lvalues can be assigned, unless their type has TYPE_READONLY.
3198    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
3199
3200 static int
3201 lvalue_p (const_tree ref)
3202 {
3203   const enum tree_code code = TREE_CODE (ref);
3204
3205   switch (code)
3206     {
3207     case REALPART_EXPR:
3208     case IMAGPART_EXPR:
3209     case COMPONENT_REF:
3210       return lvalue_p (TREE_OPERAND (ref, 0));
3211
3212     case COMPOUND_LITERAL_EXPR:
3213     case STRING_CST:
3214       return 1;
3215
3216     case INDIRECT_REF:
3217     case ARRAY_REF:
3218     case VAR_DECL:
3219     case PARM_DECL:
3220     case RESULT_DECL:
3221     case ERROR_MARK:
3222       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
3223               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
3224
3225     case BIND_EXPR:
3226       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
3227
3228     default:
3229       return 0;
3230     }
3231 }
3232 \f
3233 /* Give an error for storing in something that is 'const'.  */
3234
3235 static void
3236 readonly_error (tree arg, enum lvalue_use use)
3237 {
3238   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
3239               || use == lv_asm);
3240   /* Using this macro rather than (for example) arrays of messages
3241      ensures that all the format strings are checked at compile
3242      time.  */
3243 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3244                                    : (use == lv_increment ? (I)         \
3245                                    : (use == lv_decrement ? (D) : (AS))))
3246   if (TREE_CODE (arg) == COMPONENT_REF)
3247     {
3248       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3249         readonly_error (TREE_OPERAND (arg, 0), use);
3250       else
3251         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3252                              G_("increment of read-only member %qD"),
3253                              G_("decrement of read-only member %qD"),
3254                              G_("read-only member %qD used as %<asm%> output")),
3255                TREE_OPERAND (arg, 1));
3256     }
3257   else if (TREE_CODE (arg) == VAR_DECL)
3258     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3259                          G_("increment of read-only variable %qD"),
3260                          G_("decrement of read-only variable %qD"),
3261                          G_("read-only variable %qD used as %<asm%> output")),
3262            arg);
3263   else
3264     error (READONLY_MSG (G_("assignment of read-only location %qE"),
3265                          G_("increment of read-only location %qE"),
3266                          G_("decrement of read-only location %qE"),
3267                          G_("read-only location %qE used as %<asm%> output")),
3268            arg);
3269 }
3270
3271
3272 /* Return nonzero if REF is an lvalue valid for this language;
3273    otherwise, print an error message and return zero.  USE says
3274    how the lvalue is being used and so selects the error message.  */
3275
3276 static int
3277 lvalue_or_else (const_tree ref, enum lvalue_use use)
3278 {
3279   int win = lvalue_p (ref);
3280
3281   if (!win)
3282     lvalue_error (use);
3283
3284   return win;
3285 }
3286 \f
3287 /* Mark EXP saying that we need to be able to take the
3288    address of it; it should not be allocated in a register.
3289    Returns true if successful.  */
3290
3291 bool
3292 c_mark_addressable (tree exp)
3293 {
3294   tree x = exp;
3295
3296   while (1)
3297     switch (TREE_CODE (x))
3298       {
3299       case COMPONENT_REF:
3300         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3301           {
3302             error
3303               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3304             return false;
3305           }
3306
3307         /* ... fall through ...  */
3308
3309       case ADDR_EXPR:
3310       case ARRAY_REF:
3311       case REALPART_EXPR:
3312       case IMAGPART_EXPR:
3313         x = TREE_OPERAND (x, 0);
3314         break;
3315
3316       case COMPOUND_LITERAL_EXPR:
3317       case CONSTRUCTOR:
3318         TREE_ADDRESSABLE (x) = 1;
3319         return true;
3320
3321       case VAR_DECL:
3322       case CONST_DECL:
3323       case PARM_DECL:
3324       case RESULT_DECL:
3325         if (C_DECL_REGISTER (x)
3326             && DECL_NONLOCAL (x))
3327           {
3328             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3329               {
3330                 error
3331                   ("global register variable %qD used in nested function", x);
3332                 return false;
3333               }
3334             pedwarn ("register variable %qD used in nested function", x);
3335           }
3336         else if (C_DECL_REGISTER (x))
3337           {
3338             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3339               error ("address of global register variable %qD requested", x);
3340             else
3341               error ("address of register variable %qD requested", x);
3342             return false;
3343           }
3344
3345         /* drops in */
3346       case FUNCTION_DECL:
3347         TREE_ADDRESSABLE (x) = 1;
3348         /* drops out */
3349       default:
3350         return true;
3351     }
3352 }
3353 \f
3354 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3355
3356 tree
3357 build_conditional_expr (tree ifexp, tree op1, tree op2)
3358 {
3359   tree type1;
3360   tree type2;
3361   enum tree_code code1;
3362   enum tree_code code2;
3363   tree result_type = NULL;
3364   tree orig_op1 = op1, orig_op2 = op2;
3365
3366   /* Promote both alternatives.  */
3367
3368   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3369     op1 = default_conversion (op1);
3370   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3371     op2 = default_conversion (op2);
3372
3373   if (TREE_CODE (ifexp) == ERROR_MARK
3374       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3375       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3376     return error_mark_node;
3377
3378   type1 = TREE_TYPE (op1);
3379   code1 = TREE_CODE (type1);
3380   type2 = TREE_TYPE (op2);
3381   code2 = TREE_CODE (type2);
3382
3383   /* C90 does not permit non-lvalue arrays in conditional expressions.
3384      In C99 they will be pointers by now.  */
3385   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3386     {
3387       error ("non-lvalue array in conditional expression");
3388       return error_mark_node;
3389     }
3390
3391   /* Quickly detect the usual case where op1 and op2 have the same type
3392      after promotion.  */
3393   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3394     {
3395       if (type1 == type2)
3396         result_type = type1;
3397       else
3398         result_type = TYPE_MAIN_VARIANT (type1);
3399     }
3400   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3401             || code1 == COMPLEX_TYPE)
3402            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3403                || code2 == COMPLEX_TYPE))
3404     {
3405       result_type = c_common_type (type1, type2);
3406
3407       /* If -Wsign-compare, warn here if type1 and type2 have
3408          different signedness.  We'll promote the signed to unsigned
3409          and later code won't know it used to be different.
3410          Do this check on the original types, so that explicit casts
3411          will be considered, but default promotions won't.  */
3412       if (warn_sign_compare && !skip_evaluation)
3413         {
3414           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3415           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3416
3417           if (unsigned_op1 ^ unsigned_op2)
3418             {
3419               bool ovf;
3420
3421               /* Do not warn if the result type is signed, since the
3422                  signed type will only be chosen if it can represent
3423                  all the values of the unsigned type.  */
3424               if (!TYPE_UNSIGNED (result_type))
3425                 /* OK */;
3426               /* Do not warn if the signed quantity is an unsuffixed
3427                  integer literal (or some static constant expression
3428                  involving such literals) and it is non-negative.  */
3429               else if ((unsigned_op2
3430                         && tree_expr_nonnegative_warnv_p (op1, &ovf))
3431                        || (unsigned_op1
3432                            && tree_expr_nonnegative_warnv_p (op2, &ovf)))
3433                 /* OK */;
3434               else
3435                 warning (0, "signed and unsigned type in conditional expression");
3436             }
3437         }
3438     }
3439   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3440     {
3441       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3442         pedwarn ("ISO C forbids conditional expr with only one void side");
3443       result_type = void_type_node;
3444     }
3445   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3446     {
3447       if (comp_target_types (type1, type2))
3448         result_type = common_pointer_type (type1, type2);
3449       else if (null_pointer_constant_p (orig_op1))
3450         result_type = qualify_type (type2, type1);
3451       else if (null_pointer_constant_p (orig_op2))
3452         result_type = qualify_type (type1, type2);
3453       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3454         {
3455           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3456             pedwarn ("ISO C forbids conditional expr between "
3457                      "%<void *%> and function pointer");
3458           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3459                                                           TREE_TYPE (type2)));
3460         }
3461       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3462         {
3463           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3464             pedwarn ("ISO C forbids conditional expr between "
3465                      "%<void *%> and function pointer");
3466           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3467                                                           TREE_TYPE (type1)));
3468         }
3469       else
3470         {
3471           pedwarn ("pointer type mismatch in conditional expression");
3472           result_type = build_pointer_type (void_type_node);
3473         }
3474     }
3475   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3476     {
3477       if (!null_pointer_constant_p (orig_op2))
3478         pedwarn ("pointer/integer type mismatch in conditional expression");
3479       else
3480         {
3481           op2 = null_pointer_node;
3482         }
3483       result_type = type1;
3484     }
3485   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3486     {
3487       if (!null_pointer_constant_p (orig_op1))
3488         pedwarn ("pointer/integer type mismatch in conditional expression");
3489       else
3490         {
3491           op1 = null_pointer_node;
3492         }
3493       result_type = type2;
3494     }
3495
3496   if (!result_type)
3497     {
3498       if (flag_cond_mismatch)
3499         result_type = void_type_node;
3500       else
3501         {
3502           error ("type mismatch in conditional expression");
3503           return error_mark_node;
3504         }
3505     }
3506
3507   /* Merge const and volatile flags of the incoming types.  */
3508   result_type
3509     = build_type_variant (result_type,
3510                           TREE_READONLY (op1) || TREE_READONLY (op2),
3511                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3512
3513   if (result_type != TREE_TYPE (op1))
3514     op1 = convert_and_check (result_type, op1);
3515   if (result_type != TREE_TYPE (op2))
3516     op2 = convert_and_check (result_type, op2);
3517
3518   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3519 }
3520 \f
3521 /* Return a compound expression that performs two expressions and
3522    returns the value of the second of them.  */
3523
3524 tree
3525 build_compound_expr (tree expr1, tree expr2)
3526 {
3527   if (!TREE_SIDE_EFFECTS (expr1))
3528     {
3529       /* The left-hand operand of a comma expression is like an expression
3530          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3531          any side-effects, unless it was explicitly cast to (void).  */
3532       if (warn_unused_value)
3533         {
3534           if (VOID_TYPE_P (TREE_TYPE (expr1))
3535               && (TREE_CODE (expr1) == NOP_EXPR
3536                   || TREE_CODE (expr1) == CONVERT_EXPR))
3537             ; /* (void) a, b */
3538           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3539                    && TREE_CODE (expr1) == COMPOUND_EXPR
3540                    && (TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR
3541                        || TREE_CODE (TREE_OPERAND (expr1, 1)) == NOP_EXPR))
3542             ; /* (void) a, (void) b, c */
3543           else
3544             warning (OPT_Wunused_value,
3545                      "left-hand operand of comma expression has no effect");
3546         }
3547     }
3548
3549   /* With -Wunused, we should also warn if the left-hand operand does have
3550      side-effects, but computes a value which is not used.  For example, in
3551      `foo() + bar(), baz()' the result of the `+' operator is not used,
3552      so we should issue a warning.  */
3553   else if (warn_unused_value)
3554     warn_if_unused_value (expr1, input_location);
3555
3556   if (expr2 == error_mark_node)
3557     return error_mark_node;
3558
3559   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3560 }
3561
3562 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3563
3564 tree
3565 build_c_cast (tree type, tree expr)
3566 {
3567   tree value = expr;
3568
3569   if (type == error_mark_node || expr == error_mark_node)
3570     return error_mark_node;
3571
3572   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3573      only in <protocol> qualifications.  But when constructing cast expressions,
3574      the protocols do matter and must be kept around.  */
3575   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3576     return build1 (NOP_EXPR, type, expr);
3577
3578   type = TYPE_MAIN_VARIANT (type);
3579
3580   if (TREE_CODE (type) == ARRAY_TYPE)
3581     {
3582       error ("cast specifies array type");
3583       return error_mark_node;
3584     }
3585
3586   if (TREE_CODE (type) == FUNCTION_TYPE)
3587     {
3588       error ("cast specifies function type");
3589       return error_mark_node;
3590     }
3591
3592   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3593     {
3594       if (pedantic)
3595         {
3596           if (TREE_CODE (type) == RECORD_TYPE
3597               || TREE_CODE (type) == UNION_TYPE)
3598             pedwarn ("ISO C forbids casting nonscalar to the same type");
3599         }
3600     }
3601   else if (TREE_CODE (type) == UNION_TYPE)
3602     {
3603       tree field;
3604
3605       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3606         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3607                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3608           break;
3609
3610       if (field)
3611         {
3612           tree t;
3613
3614           if (pedantic)
3615             pedwarn ("ISO C forbids casts to union type");
3616           t = digest_init (type,
3617                            build_constructor_single (type, field, value),
3618                            true, 0);
3619           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3620           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3621           return t;
3622         }
3623       error ("cast to union type from type not present in union");
3624       return error_mark_node;
3625     }
3626   else
3627     {
3628       tree otype, ovalue;
3629
3630       if (type == void_type_node)
3631         return build1 (CONVERT_EXPR, type, value);
3632
3633       otype = TREE_TYPE (value);
3634
3635       /* Optionally warn about potentially worrisome casts.  */
3636
3637       if (warn_cast_qual
3638           && TREE_CODE (type) == POINTER_TYPE
3639           && TREE_CODE (otype) == POINTER_TYPE)
3640         {
3641           tree in_type = type;
3642           tree in_otype = otype;
3643           int added = 0;
3644           int discarded = 0;
3645
3646           /* Check that the qualifiers on IN_TYPE are a superset of
3647              the qualifiers of IN_OTYPE.  The outermost level of
3648              POINTER_TYPE nodes is uninteresting and we stop as soon
3649              as we hit a non-POINTER_TYPE node on either type.  */
3650           do
3651             {
3652               in_otype = TREE_TYPE (in_otype);
3653               in_type = TREE_TYPE (in_type);
3654
3655               /* GNU C allows cv-qualified function types.  'const'
3656                  means the function is very pure, 'volatile' means it
3657                  can't return.  We need to warn when such qualifiers
3658                  are added, not when they're taken away.  */
3659               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3660                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3661                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3662               else
3663                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3664             }
3665           while (TREE_CODE (in_type) == POINTER_TYPE
3666                  && TREE_CODE (in_otype) == POINTER_TYPE);
3667
3668           if (added)
3669             warning (OPT_Wcast_qual, "cast adds new qualifiers to function type");
3670
3671           if (discarded)
3672             /* There are qualifiers present in IN_OTYPE that are not
3673                present in IN_TYPE.  */
3674             warning (OPT_Wcast_qual, "cast discards qualifiers from pointer target type");
3675         }
3676
3677       /* Warn about possible alignment problems.  */
3678       if (STRICT_ALIGNMENT
3679           && TREE_CODE (type) == POINTER_TYPE
3680           && TREE_CODE (otype) == POINTER_TYPE
3681           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3682           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3683           /* Don't warn about opaque types, where the actual alignment
3684              restriction is unknown.  */
3685           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3686                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3687                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3688           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3689         warning (OPT_Wcast_align,
3690                  "cast increases required alignment of target type");
3691
3692       if (TREE_CODE (type) == INTEGER_TYPE
3693           && TREE_CODE (otype) == POINTER_TYPE
3694           && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
3695       /* Unlike conversion of integers to pointers, where the
3696          warning is disabled for converting constants because
3697          of cases such as SIG_*, warn about converting constant
3698          pointers to integers. In some cases it may cause unwanted
3699          sign extension, and a warning is appropriate.  */
3700         warning (OPT_Wpointer_to_int_cast,
3701                  "cast from pointer to integer of different size");
3702
3703       if (TREE_CODE (value) == CALL_EXPR
3704           && TREE_CODE (type) != TREE_CODE (otype))
3705         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3706                  "to non-matching type %qT", otype, type);
3707
3708       if (TREE_CODE (type) == POINTER_TYPE
3709           && TREE_CODE (otype) == INTEGER_TYPE
3710           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3711           /* Don't warn about converting any constant.  */
3712           && !TREE_CONSTANT (value))
3713         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3714                  "of different size");
3715
3716       if (warn_strict_aliasing <= 2)
3717         strict_aliasing_warning (otype, type, expr);
3718
3719       /* If pedantic, warn for conversions between function and object
3720          pointer types, except for converting a null pointer constant
3721          to function pointer type.  */
3722       if (pedantic
3723           && TREE_CODE (type) == POINTER_TYPE
3724           && TREE_CODE (otype) == POINTER_TYPE
3725           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3726           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3727         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3728
3729       if (pedantic
3730           && TREE_CODE (type) == POINTER_TYPE
3731           && TREE_CODE (otype) == POINTER_TYPE
3732           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3733           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3734           && !null_pointer_constant_p (value))
3735         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3736
3737       ovalue = value;
3738       value = convert (type, value);
3739
3740       /* Ignore any integer overflow caused by the cast.  */
3741       if (TREE_CODE (value) == INTEGER_CST)
3742         {
3743           if (CONSTANT_CLASS_P (ovalue) && TREE_OVERFLOW (ovalue))
3744             {
3745               if (!TREE_OVERFLOW (value))
3746                 {
3747                   /* Avoid clobbering a shared constant.  */
3748                   value = copy_node (value);
3749                   TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3750                 }
3751             }
3752           else if (TREE_OVERFLOW (value))
3753             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3754             value = build_int_cst_wide (TREE_TYPE (value),
3755                                         TREE_INT_CST_LOW (value),
3756                                         TREE_INT_CST_HIGH (value));
3757         }
3758     }
3759
3760   /* Don't let a cast be an lvalue.  */
3761   if (value == expr)
3762     value = non_lvalue (value);
3763
3764   return value;
3765 }
3766
3767 /* Interpret a cast of expression EXPR to type TYPE.  */
3768 tree
3769 c_cast_expr (struct c_type_name *type_name, tree expr)
3770 {
3771   tree type;
3772   int saved_wsp = warn_strict_prototypes;
3773
3774   /* This avoids warnings about unprototyped casts on
3775      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3776   if (TREE_CODE (expr) == INTEGER_CST)
3777     warn_strict_prototypes = 0;
3778   type = groktypename (type_name);
3779   warn_strict_prototypes = saved_wsp;
3780
3781   return build_c_cast (type, expr);
3782 }
3783 \f
3784 /* Build an assignment expression of lvalue LHS from value RHS.
3785    MODIFYCODE is the code for a binary operator that we use
3786    to combine the old value of LHS with RHS to get the new value.
3787    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3788
3789 tree
3790 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3791 {
3792   tree result;
3793   tree newrhs;
3794   tree lhstype = TREE_TYPE (lhs);
3795   tree olhstype = lhstype;
3796
3797   /* Types that aren't fully specified cannot be used in assignments.  */
3798   lhs = require_complete_type (lhs);
3799
3800   /* Avoid duplicate error messages from operands that had errors.  */
3801   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3802     return error_mark_node;
3803
3804   if (!lvalue_or_else (lhs, lv_assign))
3805     return error_mark_node;
3806
3807   STRIP_TYPE_NOPS (rhs);
3808
3809   newrhs = rhs;
3810
3811   /* If a binary op has been requested, combine the old LHS value with the RHS
3812      producing the value we should actually store into the LHS.  */
3813
3814   if (modifycode != NOP_EXPR)
3815     {
3816       lhs = stabilize_reference (lhs);
3817       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3818     }
3819
3820   /* Give an error for storing in something that is 'const'.  */
3821
3822   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3823       || ((TREE_CODE (lhstype) == RECORD_TYPE
3824            || TREE_CODE (lhstype) == UNION_TYPE)
3825           && C_TYPE_FIELDS_READONLY (lhstype)))
3826     {
3827       readonly_error (lhs, lv_assign);
3828       return error_mark_node;
3829     }
3830
3831   /* If storing into a structure or union member,
3832      it has probably been given type `int'.
3833      Compute the type that would go with
3834      the actual amount of storage the member occupies.  */
3835
3836   if (TREE_CODE (lhs) == COMPONENT_REF
3837       && (TREE_CODE (lhstype) == INTEGER_TYPE
3838           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3839           || TREE_CODE (lhstype) == REAL_TYPE
3840           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3841     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3842
3843   /* If storing in a field that is in actuality a short or narrower than one,
3844      we must store in the field in its actual type.  */
3845
3846   if (lhstype != TREE_TYPE (lhs))
3847     {
3848       lhs = copy_node (lhs);
3849       TREE_TYPE (lhs) = lhstype;
3850     }
3851
3852   /* Convert new value to destination type.  */
3853
3854   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3855                                    NULL_TREE, NULL_TREE, 0);
3856   if (TREE_CODE (newrhs) == ERROR_MARK)
3857     return error_mark_node;
3858
3859   /* Emit ObjC write barrier, if necessary.  */
3860   if (c_dialect_objc () && flag_objc_gc)
3861     {
3862       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3863       if (result)
3864         return result;
3865     }
3866
3867   /* Scan operands.  */
3868
3869   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3870   TREE_SIDE_EFFECTS (result) = 1;
3871
3872   /* If we got the LHS in a different type for storing in,
3873      convert the result back to the nominal type of LHS
3874      so that the value we return always has the same type
3875      as the LHS argument.  */
3876
3877   if (olhstype == TREE_TYPE (result))
3878     return result;
3879   return convert_for_assignment (olhstype, result, ic_assign,
3880                                  NULL_TREE, NULL_TREE, 0);
3881 }
3882 \f
3883 /* Convert value RHS to type TYPE as preparation for an assignment
3884    to an lvalue of type TYPE.
3885    The real work of conversion is done by `convert'.
3886    The purpose of this function is to generate error messages
3887    for assignments that are not allowed in C.
3888    ERRTYPE says whether it is argument passing, assignment,
3889    initialization or return.
3890
3891    FUNCTION is a tree for the function being called.
3892    PARMNUM is the number of the argument, for printing in error messages.  */
3893
3894 static tree
3895 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3896                         tree fundecl, tree function, int parmnum)
3897 {
3898   enum tree_code codel = TREE_CODE (type);
3899   tree rhstype;
3900   enum tree_code coder;
3901   tree rname = NULL_TREE;
3902   bool objc_ok = false;
3903
3904   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3905     {
3906       tree selector;
3907       /* Change pointer to function to the function itself for
3908          diagnostics.  */
3909       if (TREE_CODE (function) == ADDR_EXPR
3910           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3911         function = TREE_OPERAND (function, 0);
3912
3913       /* Handle an ObjC selector specially for diagnostics.  */
3914       selector = objc_message_selector ();
3915       rname = function;
3916       if (selector && parmnum > 2)
3917         {
3918           rname = selector;
3919           parmnum -= 2;
3920         }
3921     }
3922
3923   /* This macro is used to emit diagnostics to ensure that all format
3924      strings are complete sentences, visible to gettext and checked at
3925      compile time.  */
3926 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3927   do {                                          \
3928     switch (errtype)                            \
3929       {                                         \
3930       case ic_argpass:                          \
3931         pedwarn (AR, parmnum, rname);           \
3932         break;                                  \
3933       case ic_argpass_nonproto:                 \
3934         warning (0, AR, parmnum, rname);                \
3935         break;                                  \
3936       case ic_assign:                           \
3937         pedwarn (AS);                           \
3938         break;                                  \
3939       case ic_init:                             \
3940         pedwarn (IN);                           \
3941         break;                                  \
3942       case ic_return:                           \
3943         pedwarn (RE);                           \
3944         break;                                  \
3945       default:                                  \
3946         gcc_unreachable ();                     \
3947       }                                         \
3948   } while (0)
3949
3950   STRIP_TYPE_NOPS (rhs);
3951
3952   if (optimize && TREE_CODE (rhs) == VAR_DECL
3953            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3954     rhs = decl_constant_value_for_broken_optimization (rhs);
3955
3956   rhstype = TREE_TYPE (rhs);
3957   coder = TREE_CODE (rhstype);
3958
3959   if (coder == ERROR_MARK)
3960     return error_mark_node;
3961
3962   if (c_dialect_objc ())
3963     {
3964       int parmno;
3965
3966       switch (errtype)
3967         {
3968         case ic_return:
3969           parmno = 0;
3970           break;
3971
3972         case ic_assign:
3973           parmno = -1;
3974           break;
3975
3976         case ic_init:
3977           parmno = -2;
3978           break;
3979
3980         default:
3981           parmno = parmnum;
3982           break;
3983         }
3984
3985       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3986     }
3987
3988   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3989     return rhs;
3990
3991   if (coder == VOID_TYPE)
3992     {
3993       /* Except for passing an argument to an unprototyped function,
3994          this is a constraint violation.  When passing an argument to
3995          an unprototyped function, it is compile-time undefined;
3996          making it a constraint in that case was rejected in
3997          DR#252.  */
3998       error ("void value not ignored as it ought to be");
3999       return error_mark_node;
4000     }
4001   /* A type converts to a reference to it.
4002      This code doesn't fully support references, it's just for the
4003      special case of va_start and va_copy.  */
4004   if (codel == REFERENCE_TYPE
4005       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
4006     {
4007       if (!lvalue_p (rhs))
4008         {
4009           error ("cannot pass rvalue to reference parameter");
4010           return error_mark_node;
4011         }
4012       if (!c_mark_addressable (rhs))
4013         return error_mark_node;
4014       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
4015
4016       /* We already know that these two types are compatible, but they
4017          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
4018          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
4019          likely to be va_list, a typedef to __builtin_va_list, which
4020          is different enough that it will cause problems later.  */
4021       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
4022         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
4023
4024       rhs = build1 (NOP_EXPR, type, rhs);
4025       return rhs;
4026     }
4027   /* Some types can interconvert without explicit casts.  */
4028   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
4029            && vector_types_convertible_p (type, TREE_TYPE (rhs), true))
4030     return convert (type, rhs);
4031   /* Arithmetic types all interconvert, and enum is treated like int.  */
4032   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
4033             || codel == FIXED_POINT_TYPE
4034             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
4035             || codel == BOOLEAN_TYPE)
4036            && (coder == INTEGER_TYPE || coder == REAL_TYPE
4037                || coder == FIXED_POINT_TYPE
4038                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
4039                || coder == BOOLEAN_TYPE))
4040     return convert_and_check (type, rhs);
4041
4042   /* Aggregates in different TUs might need conversion.  */
4043   if ((codel == RECORD_TYPE || codel == UNION_TYPE)
4044       && codel == coder
4045       && comptypes (type, rhstype))
4046     return convert_and_check (type, rhs);
4047
4048   /* Conversion to a transparent union from its member types.
4049      This applies only to function arguments.  */
4050   if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
4051       && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
4052     {
4053       tree memb, marginal_memb = NULL_TREE;
4054
4055       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
4056         {
4057           tree memb_type = TREE_TYPE (memb);
4058
4059           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
4060                          TYPE_MAIN_VARIANT (rhstype)))
4061             break;
4062
4063           if (TREE_CODE (memb_type) != POINTER_TYPE)
4064             continue;
4065
4066           if (coder == POINTER_TYPE)
4067             {
4068               tree ttl = TREE_TYPE (memb_type);
4069               tree ttr = TREE_TYPE (rhstype);
4070
4071               /* Any non-function converts to a [const][volatile] void *
4072                  and vice versa; otherwise, targets must be the same.
4073                  Meanwhile, the lhs target must have all the qualifiers of
4074                  the rhs.  */
4075               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4076                   || comp_target_types (memb_type, rhstype))
4077                 {
4078                   /* If this type won't generate any warnings, use it.  */
4079                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
4080                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
4081                            && TREE_CODE (ttl) == FUNCTION_TYPE)
4082                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4083                              == TYPE_QUALS (ttr))
4084                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
4085                              == TYPE_QUALS (ttl))))
4086                     break;
4087
4088                   /* Keep looking for a better type, but remember this one.  */
4089                   if (!marginal_memb)
4090                     marginal_memb = memb;
4091                 }
4092             }
4093
4094           /* Can convert integer zero to any pointer type.  */
4095           if (null_pointer_constant_p (rhs))
4096             {
4097               rhs = null_pointer_node;
4098               break;
4099             }
4100         }
4101
4102       if (memb || marginal_memb)
4103         {
4104           if (!memb)
4105             {
4106               /* We have only a marginally acceptable member type;
4107                  it needs a warning.  */
4108               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
4109               tree ttr = TREE_TYPE (rhstype);
4110
4111               /* Const and volatile mean something different for function
4112                  types, so the usual warnings are not appropriate.  */
4113               if (TREE_CODE (ttr) == FUNCTION_TYPE
4114                   && TREE_CODE (ttl) == FUNCTION_TYPE)
4115                 {
4116                   /* Because const and volatile on functions are
4117                      restrictions that say the function will not do
4118                      certain things, it is okay to use a const or volatile
4119                      function where an ordinary one is wanted, but not
4120                      vice-versa.  */
4121                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4122                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
4123                                             "makes qualified function "
4124                                             "pointer from unqualified"),
4125                                          G_("assignment makes qualified "
4126                                             "function pointer from "
4127                                             "unqualified"),
4128                                          G_("initialization makes qualified "
4129                                             "function pointer from "
4130                                             "unqualified"),
4131                                          G_("return makes qualified function "
4132                                             "pointer from unqualified"));
4133                 }
4134               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4135                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4136                                         "qualifiers from pointer target type"),
4137                                      G_("assignment discards qualifiers "
4138                                         "from pointer target type"),
4139                                      G_("initialization discards qualifiers "
4140                                         "from pointer target type"),
4141                                      G_("return discards qualifiers from "
4142                                         "pointer target type"));
4143
4144               memb = marginal_memb;
4145             }
4146
4147           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
4148             pedwarn ("ISO C prohibits argument conversion to union type");
4149
4150           rhs = fold_convert (TREE_TYPE (memb), rhs);
4151           return build_constructor_single (type, memb, rhs);
4152         }
4153     }
4154
4155   /* Conversions among pointers */
4156   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
4157            && (coder == codel))
4158     {
4159       tree ttl = TREE_TYPE (type);
4160       tree ttr = TREE_TYPE (rhstype);
4161       tree mvl = ttl;
4162       tree mvr = ttr;
4163       bool is_opaque_pointer;
4164       int target_cmp = 0;   /* Cache comp_target_types () result.  */
4165
4166       if (TREE_CODE (mvl) != ARRAY_TYPE)
4167         mvl = TYPE_MAIN_VARIANT (mvl);
4168       if (TREE_CODE (mvr) != ARRAY_TYPE)
4169         mvr = TYPE_MAIN_VARIANT (mvr);
4170       /* Opaque pointers are treated like void pointers.  */
4171       is_opaque_pointer = (targetm.vector_opaque_p (type)
4172                            || targetm.vector_opaque_p (rhstype))
4173         && TREE_CODE (ttl) == VECTOR_TYPE
4174         && TREE_CODE (ttr) == VECTOR_TYPE;
4175
4176       /* C++ does not allow the implicit conversion void* -> T*.  However,
4177          for the purpose of reducing the number of false positives, we
4178          tolerate the special case of
4179
4180                 int *p = NULL;
4181
4182          where NULL is typically defined in C to be '(void *) 0'.  */
4183       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
4184         warning (OPT_Wc___compat, "request for implicit conversion from "
4185                  "%qT to %qT not permitted in C++", rhstype, type);
4186
4187       /* Check if the right-hand side has a format attribute but the
4188          left-hand side doesn't.  */
4189       if (warn_missing_format_attribute
4190           && check_missing_format_attribute (type, rhstype))
4191         {
4192           switch (errtype)
4193           {
4194           case ic_argpass:
4195           case ic_argpass_nonproto:
4196             warning (OPT_Wmissing_format_attribute,
4197                      "argument %d of %qE might be "
4198                      "a candidate for a format attribute",
4199                      parmnum, rname);
4200             break;
4201           case ic_assign:
4202             warning (OPT_Wmissing_format_attribute,
4203                      "assignment left-hand side might be "
4204                      "a candidate for a format attribute");
4205             break;
4206           case ic_init:
4207             warning (OPT_Wmissing_format_attribute,
4208                      "initialization left-hand side might be "
4209                      "a candidate for a format attribute");
4210             break;
4211           case ic_return:
4212             warning (OPT_Wmissing_format_attribute,
4213                      "return type might be "
4214                      "a candidate for a format attribute");
4215             break;
4216           default:
4217             gcc_unreachable ();
4218           }
4219         }
4220
4221       /* Any non-function converts to a [const][volatile] void *
4222          and vice versa; otherwise, targets must be the same.
4223          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
4224       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4225           || (target_cmp = comp_target_types (type, rhstype))
4226           || is_opaque_pointer
4227           || (c_common_unsigned_type (mvl)
4228               == c_common_unsigned_type (mvr)))
4229         {
4230           if (pedantic
4231               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
4232                   ||
4233                   (VOID_TYPE_P (ttr)
4234                    && !null_pointer_constant_p (rhs)
4235                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
4236             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
4237                                     "%qE between function pointer "
4238                                     "and %<void *%>"),
4239                                  G_("ISO C forbids assignment between "
4240                                     "function pointer and %<void *%>"),
4241                                  G_("ISO C forbids initialization between "
4242                                     "function pointer and %<void *%>"),
4243                                  G_("ISO C forbids return between function "
4244                                     "pointer and %<void *%>"));
4245           /* Const and volatile mean something different for function types,
4246              so the usual warnings are not appropriate.  */
4247           else if (TREE_CODE (ttr) != FUNCTION_TYPE
4248                    && TREE_CODE (ttl) != FUNCTION_TYPE)
4249             {
4250               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
4251                 {
4252                   /* Types differing only by the presence of the 'volatile'
4253                      qualifier are acceptable if the 'volatile' has been added
4254                      in by the Objective-C EH machinery.  */
4255                   if (!objc_type_quals_match (ttl, ttr))
4256                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4257                                             "qualifiers from pointer target type"),
4258                                          G_("assignment discards qualifiers "
4259                                             "from pointer target type"),
4260                                          G_("initialization discards qualifiers "
4261                                             "from pointer target type"),
4262                                          G_("return discards qualifiers from "
4263                                             "pointer target type"));
4264                 }
4265               /* If this is not a case of ignoring a mismatch in signedness,
4266                  no warning.  */
4267               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4268                        || target_cmp)
4269                 ;
4270               /* If there is a mismatch, do warn.  */
4271               else if (warn_pointer_sign)
4272                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4273                                         "%d of %qE differ in signedness"),
4274                                      G_("pointer targets in assignment "
4275                                         "differ in signedness"),
4276                                      G_("pointer targets in initialization "
4277                                         "differ in signedness"),
4278                                      G_("pointer targets in return differ "
4279                                         "in signedness"));
4280             }
4281           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4282                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4283             {
4284               /* Because const and volatile on functions are restrictions
4285                  that say the function will not do certain things,
4286                  it is okay to use a const or volatile function
4287                  where an ordinary one is wanted, but not vice-versa.  */
4288               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4289                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4290                                         "qualified function pointer "
4291                                         "from unqualified"),
4292                                      G_("assignment makes qualified function "
4293                                         "pointer from unqualified"),
4294                                      G_("initialization makes qualified "
4295                                         "function pointer from unqualified"),
4296                                      G_("return makes qualified function "
4297                                         "pointer from unqualified"));
4298             }
4299         }
4300       else
4301         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4302         if (!objc_ok)
4303           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4304                                   "incompatible pointer type"),
4305                                G_("assignment from incompatible pointer type"),
4306                                G_("initialization from incompatible "
4307                                   "pointer type"),
4308                                G_("return from incompatible pointer type"));
4309
4310       return convert (type, rhs);
4311     }
4312   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4313     {
4314       /* ??? This should not be an error when inlining calls to
4315          unprototyped functions.  */
4316       error ("invalid use of non-lvalue array");
4317       return error_mark_node;
4318     }
4319   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4320     {
4321       /* An explicit constant 0 can convert to a pointer,
4322          or one that results from arithmetic, even including
4323          a cast to integer type.  */
4324       if (!null_pointer_constant_p (rhs))
4325         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4326                                 "pointer from integer without a cast"),
4327                              G_("assignment makes pointer from integer "
4328                                 "without a cast"),
4329                              G_("initialization makes pointer from "
4330                                 "integer without a cast"),
4331                              G_("return makes pointer from integer "
4332                                 "without a cast"));
4333
4334       return convert (type, rhs);
4335     }
4336   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4337     {
4338       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4339                               "from pointer without a cast"),
4340                            G_("assignment makes integer from pointer "
4341                               "without a cast"),
4342                            G_("initialization makes integer from pointer "
4343                               "without a cast"),
4344                            G_("return makes integer from pointer "
4345                               "without a cast"));
4346       return convert (type, rhs);
4347     }
4348   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4349     return convert (type, rhs);
4350
4351   switch (errtype)
4352     {
4353     case ic_argpass:
4354     case ic_argpass_nonproto:
4355       /* ??? This should not be an error when inlining calls to
4356          unprototyped functions.  */
4357       error ("incompatible type for argument %d of %qE", parmnum, rname);
4358       break;
4359     case ic_assign:
4360       error ("incompatible types in assignment");
4361       break;
4362     case ic_init:
4363       error ("incompatible types in initialization");
4364       break;
4365     case ic_return:
4366       error ("incompatible types in return");
4367       break;
4368     default:
4369       gcc_unreachable ();
4370     }
4371
4372   return error_mark_node;
4373 }
4374 \f
4375 /* If VALUE is a compound expr all of whose expressions are constant, then
4376    return its value.  Otherwise, return error_mark_node.
4377
4378    This is for handling COMPOUND_EXPRs as initializer elements
4379    which is allowed with a warning when -pedantic is specified.  */
4380
4381 static tree
4382 valid_compound_expr_initializer (tree value, tree endtype)
4383 {
4384   if (TREE_CODE (value) == COMPOUND_EXPR)
4385     {
4386       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4387           == error_mark_node)
4388         return error_mark_node;
4389       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4390                                               endtype);
4391     }
4392   else if (!initializer_constant_valid_p (value, endtype))
4393     return error_mark_node;
4394   else
4395     return value;
4396 }
4397 \f
4398 /* Perform appropriate conversions on the initial value of a variable,
4399    store it in the declaration DECL,
4400    and print any error messages that are appropriate.
4401    If the init is invalid, store an ERROR_MARK.  */
4402
4403 void
4404 store_init_value (tree decl, tree init)
4405 {
4406   tree value, type;
4407
4408   /* If variable's type was invalidly declared, just ignore it.  */
4409
4410   type = TREE_TYPE (decl);
4411   if (TREE_CODE (type) == ERROR_MARK)
4412     return;
4413
4414   /* Digest the specified initializer into an expression.  */
4415
4416   value = digest_init (type, init, true, TREE_STATIC (decl));
4417
4418   /* Store the expression if valid; else report error.  */
4419
4420   if (!in_system_header
4421       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4422     warning (OPT_Wtraditional, "traditional C rejects automatic "
4423              "aggregate initialization");
4424
4425   DECL_INITIAL (decl) = value;
4426
4427   /* ANSI wants warnings about out-of-range constant initializers.  */
4428   STRIP_TYPE_NOPS (value);
4429   if (TREE_STATIC (decl))
4430     constant_expression_warning (value);
4431
4432   /* Check if we need to set array size from compound literal size.  */
4433   if (TREE_CODE (type) == ARRAY_TYPE
4434       && TYPE_DOMAIN (type) == 0
4435       && value != error_mark_node)
4436     {
4437       tree inside_init = init;
4438
4439       STRIP_TYPE_NOPS (inside_init);
4440       inside_init = fold (inside_init);
4441
4442       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4443         {
4444           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4445
4446           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4447             {
4448               /* For int foo[] = (int [3]){1}; we need to set array size
4449                  now since later on array initializer will be just the
4450                  brace enclosed list of the compound literal.  */
4451               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4452               TREE_TYPE (decl) = type;
4453               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4454               layout_type (type);
4455               layout_decl (cldecl, 0);
4456             }
4457         }
4458     }
4459 }
4460 \f
4461 /* Methods for storing and printing names for error messages.  */
4462
4463 /* Implement a spelling stack that allows components of a name to be pushed
4464    and popped.  Each element on the stack is this structure.  */
4465
4466 struct spelling
4467 {
4468   int kind;
4469   union
4470     {
4471       unsigned HOST_WIDE_INT i;
4472       const char *s;
4473     } u;
4474 };
4475
4476 #define SPELLING_STRING 1
4477 #define SPELLING_MEMBER 2
4478 #define SPELLING_BOUNDS 3
4479
4480 static struct spelling *spelling;       /* Next stack element (unused).  */
4481 static struct spelling *spelling_base;  /* Spelling stack base.  */
4482 static int spelling_size;               /* Size of the spelling stack.  */
4483
4484 /* Macros to save and restore the spelling stack around push_... functions.
4485    Alternative to SAVE_SPELLING_STACK.  */
4486
4487 #define SPELLING_DEPTH() (spelling - spelling_base)
4488 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4489
4490 /* Push an element on the spelling stack with type KIND and assign VALUE
4491    to MEMBER.  */
4492
4493 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4494 {                                                                       \
4495   int depth = SPELLING_DEPTH ();                                        \
4496                                                                         \
4497   if (depth >= spelling_size)                                           \
4498     {                                                                   \
4499       spelling_size += 10;                                              \
4500       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4501                                   spelling_size);                       \
4502       RESTORE_SPELLING_DEPTH (depth);                                   \
4503     }                                                                   \
4504                                                                         \
4505   spelling->kind = (KIND);                                              \
4506   spelling->MEMBER = (VALUE);                                           \
4507   spelling++;                                                           \
4508 }
4509
4510 /* Push STRING on the stack.  Printed literally.  */
4511
4512 static void
4513 push_string (const char *string)
4514 {
4515   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4516 }
4517
4518 /* Push a member name on the stack.  Printed as '.' STRING.  */
4519
4520 static void
4521 push_member_name (tree decl)
4522 {
4523   const char *const string
4524     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4525   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4526 }
4527
4528 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4529
4530 static void
4531 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4532 {
4533   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4534 }
4535
4536 /* Compute the maximum size in bytes of the printed spelling.  */
4537
4538 static int
4539 spelling_length (void)
4540 {
4541   int size = 0;
4542   struct spelling *p;
4543
4544   for (p = spelling_base; p < spelling; p++)
4545     {
4546       if (p->kind == SPELLING_BOUNDS)
4547         size += 25;
4548       else
4549         size += strlen (p->u.s) + 1;
4550     }
4551
4552   return size;
4553 }
4554
4555 /* Print the spelling to BUFFER and return it.  */
4556
4557 static char *
4558 print_spelling (char *buffer)
4559 {
4560   char *d = buffer;
4561   struct spelling *p;
4562
4563   for (p = spelling_base; p < spelling; p++)
4564     if (p->kind == SPELLING_BOUNDS)
4565       {
4566         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4567         d += strlen (d);
4568       }
4569     else
4570       {
4571         const char *s;
4572         if (p->kind == SPELLING_MEMBER)
4573           *d++ = '.';
4574         for (s = p->u.s; (*d = *s++); d++)
4575           ;
4576       }
4577   *d++ = '\0';
4578   return buffer;
4579 }
4580
4581 /* Issue an error message for a bad initializer component.
4582    MSGID identifies the message.
4583    The component name is taken from the spelling stack.  */
4584
4585 void
4586 error_init (const char *msgid)
4587 {
4588   char *ofwhat;
4589
4590   error ("%s", _(msgid));
4591   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4592   if (*ofwhat)
4593     error ("(near initialization for %qs)", ofwhat);
4594 }
4595
4596 /* Issue a pedantic warning for a bad initializer component.
4597    MSGID identifies the message.
4598    The component name is taken from the spelling stack.  */
4599
4600 void
4601 pedwarn_init (const char *msgid)
4602 {
4603   char *ofwhat;
4604
4605   pedwarn ("%s", _(msgid));
4606   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4607   if (*ofwhat)
4608     pedwarn ("(near initialization for %qs)", ofwhat);
4609 }
4610
4611 /* Issue a warning for a bad initializer component.
4612    MSGID identifies the message.
4613    The component name is taken from the spelling stack.  */
4614
4615 static void
4616 warning_init (const char *msgid)
4617 {
4618   char *ofwhat;
4619
4620   warning (0, "%s", _(msgid));
4621   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4622   if (*ofwhat)
4623     warning (0, "(near initialization for %qs)", ofwhat);
4624 }
4625 \f
4626 /* If TYPE is an array type and EXPR is a parenthesized string
4627    constant, warn if pedantic that EXPR is being used to initialize an
4628    object of type TYPE.  */
4629
4630 void
4631 maybe_warn_string_init (tree type, struct c_expr expr)
4632 {
4633   if (pedantic
4634       && TREE_CODE (type) == ARRAY_TYPE
4635       && TREE_CODE (expr.value) == STRING_CST
4636       && expr.original_code != STRING_CST)
4637     pedwarn_init ("array initialized from parenthesized string constant");
4638 }
4639
4640 /* Digest the parser output INIT as an initializer for type TYPE.
4641    Return a C expression of type TYPE to represent the initial value.
4642
4643    If INIT is a string constant, STRICT_STRING is true if it is
4644    unparenthesized or we should not warn here for it being parenthesized.
4645    For other types of INIT, STRICT_STRING is not used.
4646
4647    REQUIRE_CONSTANT requests an error if non-constant initializers or
4648    elements are seen.  */
4649
4650 static tree
4651 digest_init (tree type, tree init, bool strict_string, int require_constant)
4652 {
4653   enum tree_code code = TREE_CODE (type);
4654   tree inside_init = init;
4655
4656   if (type == error_mark_node
4657       || !init
4658       || init == error_mark_node
4659       || TREE_TYPE (init) == error_mark_node)
4660     return error_mark_node;
4661
4662   STRIP_TYPE_NOPS (inside_init);
4663
4664   inside_init = fold (inside_init);
4665
4666   /* Initialization of an array of chars from a string constant
4667      optionally enclosed in braces.  */
4668
4669   if (code == ARRAY_TYPE && inside_init
4670       && TREE_CODE (inside_init) == STRING_CST)
4671     {
4672       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4673       /* Note that an array could be both an array of character type
4674          and an array of wchar_t if wchar_t is signed char or unsigned
4675          char.  */
4676       bool char_array = (typ1 == char_type_node
4677                          || typ1 == signed_char_type_node
4678                          || typ1 == unsigned_char_type_node);
4679       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4680       if (char_array || wchar_array)
4681         {
4682           struct c_expr expr;
4683           bool char_string;
4684           expr.value = inside_init;
4685           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4686           maybe_warn_string_init (type, expr);
4687
4688           char_string
4689             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4690                == char_type_node);
4691
4692           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4693                          TYPE_MAIN_VARIANT (type)))
4694             return inside_init;
4695
4696           if (!wchar_array && !char_string)
4697             {
4698               error_init ("char-array initialized from wide string");
4699               return error_mark_node;
4700             }
4701           if (char_string && !char_array)
4702             {
4703               error_init ("wchar_t-array initialized from non-wide string");
4704               return error_mark_node;
4705             }
4706
4707           TREE_TYPE (inside_init) = type;
4708           if (TYPE_DOMAIN (type) != 0
4709               && TYPE_SIZE (type) != 0
4710               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4711               /* Subtract 1 (or sizeof (wchar_t))
4712                  because it's ok to ignore the terminating null char
4713                  that is counted in the length of the constant.  */
4714               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4715                                        TREE_STRING_LENGTH (inside_init)
4716                                        - ((TYPE_PRECISION (typ1)
4717                                            != TYPE_PRECISION (char_type_node))
4718                                           ? (TYPE_PRECISION (wchar_type_node)
4719                                              / BITS_PER_UNIT)
4720                                           : 1)))
4721             pedwarn_init ("initializer-string for array of chars is too long");
4722
4723           return inside_init;
4724         }
4725       else if (INTEGRAL_TYPE_P (typ1))
4726         {
4727           error_init ("array of inappropriate type initialized "
4728                       "from string constant");
4729           return error_mark_node;
4730         }
4731     }
4732
4733   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4734      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4735      below and handle as a constructor.  */
4736   if (code == VECTOR_TYPE
4737       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4738       && vector_types_convertible_p (TREE_TYPE (inside_init), type, true)
4739       && TREE_CONSTANT (inside_init))
4740     {
4741       if (TREE_CODE (inside_init) == VECTOR_CST
4742           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4743                         TYPE_MAIN_VARIANT (type)))
4744         return inside_init;
4745
4746       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4747         {
4748           unsigned HOST_WIDE_INT ix;
4749           tree value;
4750           bool constant_p = true;
4751
4752           /* Iterate through elements and check if all constructor
4753              elements are *_CSTs.  */
4754           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4755             if (!CONSTANT_CLASS_P (value))
4756               {
4757                 constant_p = false;
4758                 break;
4759               }
4760
4761           if (constant_p)
4762             return build_vector_from_ctor (type,
4763                                            CONSTRUCTOR_ELTS (inside_init));
4764         }
4765     }
4766
4767   /* Any type can be initialized
4768      from an expression of the same type, optionally with braces.  */
4769
4770   if (inside_init && TREE_TYPE (inside_init) != 0
4771       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4772                      TYPE_MAIN_VARIANT (type))
4773           || (code == ARRAY_TYPE
4774               && comptypes (TREE_TYPE (inside_init), type))
4775           || (code == VECTOR_TYPE
4776               && comptypes (TREE_TYPE (inside_init), type))
4777           || (code == POINTER_TYPE
4778               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4779               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4780                             TREE_TYPE (type)))))
4781     {
4782       if (code == POINTER_TYPE)
4783         {
4784           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4785             {
4786               if (TREE_CODE (inside_init) == STRING_CST
4787                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4788                 inside_init = array_to_pointer_conversion (inside_init);
4789               else
4790                 {
4791                   error_init ("invalid use of non-lvalue array");
4792                   return error_mark_node;
4793                 }
4794             }
4795         }
4796
4797       if (code == VECTOR_TYPE)
4798         /* Although the types are compatible, we may require a
4799            conversion.  */
4800         inside_init = convert (type, inside_init);
4801
4802       if (require_constant
4803           && (code == VECTOR_TYPE || !flag_isoc99)
4804           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4805         {
4806           /* As an extension, allow initializing objects with static storage
4807              duration with compound literals (which are then treated just as
4808              the brace enclosed list they contain).  Also allow this for
4809              vectors, as we can only assign them with compound literals.  */
4810           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4811           inside_init = DECL_INITIAL (decl);
4812         }
4813
4814       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4815           && TREE_CODE (inside_init) != CONSTRUCTOR)
4816         {
4817           error_init ("array initialized from non-constant array expression");
4818           return error_mark_node;
4819         }
4820
4821       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4822         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4823
4824       /* Compound expressions can only occur here if -pedantic or
4825          -pedantic-errors is specified.  In the later case, we always want
4826          an error.  In the former case, we simply want a warning.  */
4827       if (require_constant && pedantic
4828           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4829         {
4830           inside_init
4831             = valid_compound_expr_initializer (inside_init,
4832                                                TREE_TYPE (inside_init));
4833           if (inside_init == error_mark_node)
4834             error_init ("initializer element is not constant");
4835           else
4836             pedwarn_init ("initializer element is not constant");
4837           if (flag_pedantic_errors)
4838             inside_init = error_mark_node;
4839         }
4840       else if (require_constant
4841                && !initializer_constant_valid_p (inside_init,
4842                                                  TREE_TYPE (inside_init)))
4843         {
4844           error_init ("initializer element is not constant");
4845           inside_init = error_mark_node;
4846         }
4847
4848       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4849       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4850         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4851                                               NULL_TREE, 0);
4852       return inside_init;
4853     }
4854
4855   /* Handle scalar types, including conversions.  */
4856
4857   if (code == INTEGER_TYPE || code == REAL_TYPE || code == FIXED_POINT_TYPE
4858       || code == POINTER_TYPE || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE
4859       || code == COMPLEX_TYPE || code == VECTOR_TYPE)
4860     {
4861       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4862           && (TREE_CODE (init) == STRING_CST
4863               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4864         init = array_to_pointer_conversion (init);
4865       inside_init
4866         = convert_for_assignment (type, init, ic_init,
4867                                   NULL_TREE, NULL_TREE, 0);
4868
4869       /* Check to see if we have already given an error message.  */
4870       if (inside_init == error_mark_node)
4871         ;
4872       else if (require_constant && !TREE_CONSTANT (inside_init))
4873         {
4874           error_init ("initializer element is not constant");
4875           inside_init = error_mark_node;
4876         }
4877       else if (require_constant
4878                && !initializer_constant_valid_p (inside_init,
4879                                                  TREE_TYPE (inside_init)))
4880         {
4881           error_init ("initializer element is not computable at load time");
4882           inside_init = error_mark_node;
4883         }
4884
4885       return inside_init;
4886     }
4887
4888   /* Come here only for records and arrays.  */
4889
4890   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4891     {
4892       error_init ("variable-sized object may not be initialized");
4893       return error_mark_node;
4894     }
4895
4896   error_init ("invalid initializer");
4897   return error_mark_node;
4898 }
4899 \f
4900 /* Handle initializers that use braces.  */
4901
4902 /* Type of object we are accumulating a constructor for.
4903    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4904 static tree constructor_type;
4905
4906 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4907    left to fill.  */
4908 static tree constructor_fields;
4909
4910 /* For an ARRAY_TYPE, this is the specified index
4911    at which to store the next element we get.  */
4912 static tree constructor_index;
4913
4914 /* For an ARRAY_TYPE, this is the maximum index.  */
4915 static tree constructor_max_index;
4916
4917 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4918 static tree constructor_unfilled_fields;
4919
4920 /* For an ARRAY_TYPE, this is the index of the first element
4921    not yet written out.  */
4922 static tree constructor_unfilled_index;
4923
4924 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4925    This is so we can generate gaps between fields, when appropriate.  */
4926 static tree constructor_bit_index;
4927
4928 /* If we are saving up the elements rather than allocating them,
4929    this is the list of elements so far (in reverse order,
4930    most recent first).  */
4931 static VEC(constructor_elt,gc) *constructor_elements;
4932
4933 /* 1 if constructor should be incrementally stored into a constructor chain,
4934    0 if all the elements should be kept in AVL tree.  */
4935 static int constructor_incremental;
4936
4937 /* 1 if so far this constructor's elements are all compile-time constants.  */
4938 static int constructor_constant;
4939
4940 /* 1 if so far this constructor's elements are all valid address constants.  */
4941 static int constructor_simple;
4942
4943 /* 1 if this constructor is erroneous so far.  */
4944 static int constructor_erroneous;
4945
4946 /* Structure for managing pending initializer elements, organized as an
4947    AVL tree.  */
4948
4949 struct init_node
4950 {
4951   struct init_node *left, *right;
4952   struct init_node *parent;
4953   int balance;
4954   tree purpose;
4955   tree value;
4956 };
4957
4958 /* Tree of pending elements at this constructor level.
4959    These are elements encountered out of order
4960    which belong at places we haven't reached yet in actually
4961    writing the output.
4962    Will never hold tree nodes across GC runs.  */
4963 static struct init_node *constructor_pending_elts;
4964
4965 /* The SPELLING_DEPTH of this constructor.  */
4966 static int constructor_depth;
4967
4968 /* DECL node for which an initializer is being read.
4969    0 means we are reading a constructor expression
4970    such as (struct foo) {...}.  */
4971 static tree constructor_decl;
4972
4973 /* Nonzero if this is an initializer for a top-level decl.  */
4974 static int constructor_top_level;
4975
4976 /* Nonzero if there were any member designators in this initializer.  */
4977 static int constructor_designated;
4978
4979 /* Nesting depth of designator list.  */
4980 static int designator_depth;
4981
4982 /* Nonzero if there were diagnosed errors in this designator list.  */
4983 static int designator_erroneous;
4984
4985 \f
4986 /* This stack has a level for each implicit or explicit level of
4987    structuring in the initializer, including the outermost one.  It
4988    saves the values of most of the variables above.  */
4989
4990 struct constructor_range_stack;
4991
4992 struct constructor_stack
4993 {
4994   struct constructor_stack *next;
4995   tree type;
4996   tree fields;
4997   tree index;
4998   tree max_index;
4999   tree unfilled_index;
5000   tree unfilled_fields;
5001   tree bit_index;
5002   VEC(constructor_elt,gc) *elements;
5003   struct init_node *pending_elts;
5004   int offset;
5005   int depth;
5006   /* If value nonzero, this value should replace the entire
5007      constructor at this level.  */
5008   struct c_expr replacement_value;
5009   struct constructor_range_stack *range_stack;
5010   char constant;
5011   char simple;
5012   char implicit;
5013   char erroneous;
5014   char outer;
5015   char incremental;
5016   char designated;
5017 };
5018
5019 static struct constructor_stack *constructor_stack;
5020
5021 /* This stack represents designators from some range designator up to
5022    the last designator in the list.  */
5023
5024 struct constructor_range_stack
5025 {
5026   struct constructor_range_stack *next, *prev;
5027   struct constructor_stack *stack;
5028   tree range_start;
5029   tree index;
5030   tree range_end;
5031   tree fields;
5032 };
5033
5034 static struct constructor_range_stack *constructor_range_stack;
5035
5036 /* This stack records separate initializers that are nested.
5037    Nested initializers can't happen in ANSI C, but GNU C allows them
5038    in cases like { ... (struct foo) { ... } ... }.  */
5039
5040 struct initializer_stack
5041 {
5042   struct initializer_stack *next;
5043   tree decl;
5044   struct constructor_stack *constructor_stack;
5045   struct constructor_range_stack *constructor_range_stack;
5046   VEC(constructor_elt,gc) *elements;
5047   struct spelling *spelling;
5048   struct spelling *spelling_base;
5049   int spelling_size;
5050   char top_level;
5051   char require_constant_value;
5052   char require_constant_elements;
5053 };
5054
5055 static struct initializer_stack *initializer_stack;
5056 \f
5057 /* Prepare to parse and output the initializer for variable DECL.  */
5058
5059 void
5060 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
5061 {
5062   const char *locus;
5063   struct initializer_stack *p = XNEW (struct initializer_stack);
5064
5065   p->decl = constructor_decl;
5066   p->require_constant_value = require_constant_value;
5067   p->require_constant_elements = require_constant_elements;
5068   p->constructor_stack = constructor_stack;
5069   p->constructor_range_stack = constructor_range_stack;
5070   p->elements = constructor_elements;
5071   p->spelling = spelling;
5072   p->spelling_base = spelling_base;
5073   p->spelling_size = spelling_size;
5074   p->top_level = constructor_top_level;
5075   p->next = initializer_stack;
5076   initializer_stack = p;
5077
5078   constructor_decl = decl;
5079   constructor_designated = 0;
5080   constructor_top_level = top_level;
5081
5082   if (decl != 0 && decl != error_mark_node)
5083     {
5084       require_constant_value = TREE_STATIC (decl);
5085       require_constant_elements
5086         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
5087            /* For a scalar, you can always use any value to initialize,
5088               even within braces.  */
5089            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
5090                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
5091                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
5092                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
5093       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
5094     }
5095   else
5096     {
5097       require_constant_value = 0;
5098       require_constant_elements = 0;
5099       locus = "(anonymous)";
5100     }
5101
5102   constructor_stack = 0;
5103   constructor_range_stack = 0;
5104
5105   missing_braces_mentioned = 0;
5106
5107   spelling_base = 0;
5108   spelling_size = 0;
5109   RESTORE_SPELLING_DEPTH (0);
5110
5111   if (locus)
5112     push_string (locus);
5113 }
5114
5115 void
5116 finish_init (void)
5117 {
5118   struct initializer_stack *p = initializer_stack;
5119
5120   /* Free the whole constructor stack of this initializer.  */
5121   while (constructor_stack)
5122     {
5123       struct constructor_stack *q = constructor_stack;
5124       constructor_stack = q->next;
5125       free (q);
5126     }
5127
5128   gcc_assert (!constructor_range_stack);
5129
5130   /* Pop back to the data of the outer initializer (if any).  */
5131   free (spelling_base);
5132
5133   constructor_decl = p->decl;
5134   require_constant_value = p->require_constant_value;
5135   require_constant_elements = p->require_constant_elements;
5136   constructor_stack = p->constructor_stack;
5137   constructor_range_stack = p->constructor_range_stack;
5138   constructor_elements = p->elements;
5139   spelling = p->spelling;
5140   spelling_base = p->spelling_base;
5141   spelling_size = p->spelling_size;
5142   constructor_top_level = p->top_level;
5143   initializer_stack = p->next;
5144   free (p);
5145 }
5146 \f
5147 /* Call here when we see the initializer is surrounded by braces.
5148    This is instead of a call to push_init_level;
5149    it is matched by a call to pop_init_level.
5150
5151    TYPE is the type to initialize, for a constructor expression.
5152    For an initializer for a decl, TYPE is zero.  */
5153
5154 void
5155 really_start_incremental_init (tree type)
5156 {
5157   struct constructor_stack *p = XNEW (struct constructor_stack);
5158
5159   if (type == 0)
5160     type = TREE_TYPE (constructor_decl);
5161
5162   if (targetm.vector_opaque_p (type))
5163     error ("opaque vector types cannot be initialized");
5164
5165   p->type = constructor_type;
5166   p->fields = constructor_fields;
5167   p->index = constructor_index;
5168   p->max_index = constructor_max_index;
5169   p->unfilled_index = constructor_unfilled_index;
5170   p->unfilled_fields = constructor_unfilled_fields;
5171   p->bit_index = constructor_bit_index;
5172   p->elements = constructor_elements;
5173   p->constant = constructor_constant;
5174   p->simple = constructor_simple;
5175   p->erroneous = constructor_erroneous;
5176   p->pending_elts = constructor_pending_elts;
5177   p->depth = constructor_depth;
5178   p->replacement_value.value = 0;
5179   p->replacement_value.original_code = ERROR_MARK;
5180   p->implicit = 0;
5181   p->range_stack = 0;
5182   p->outer = 0;
5183   p->incremental = constructor_incremental;
5184   p->designated = constructor_designated;
5185   p->next = 0;
5186   constructor_stack = p;
5187
5188   constructor_constant = 1;
5189   constructor_simple = 1;
5190   constructor_depth = SPELLING_DEPTH ();
5191   constructor_elements = 0;
5192   constructor_pending_elts = 0;
5193   constructor_type = type;
5194   constructor_incremental = 1;
5195   constructor_designated = 0;
5196   designator_depth = 0;
5197   designator_erroneous = 0;
5198
5199   if (TREE_CODE (constructor_type) == RECORD_TYPE
5200       || TREE_CODE (constructor_type) == UNION_TYPE)
5201     {
5202       constructor_fields = TYPE_FIELDS (constructor_type);
5203       /* Skip any nameless bit fields at the beginning.  */
5204       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5205              && DECL_NAME (constructor_fields) == 0)
5206         constructor_fields = TREE_CHAIN (constructor_fields);
5207
5208       constructor_unfilled_fields = constructor_fields;
5209       constructor_bit_index = bitsize_zero_node;
5210     }
5211   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5212     {
5213       if (TYPE_DOMAIN (constructor_type))
5214         {
5215           constructor_max_index
5216             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5217
5218           /* Detect non-empty initializations of zero-length arrays.  */
5219           if (constructor_max_index == NULL_TREE
5220               && TYPE_SIZE (constructor_type))
5221             constructor_max_index = build_int_cst (NULL_TREE, -1);
5222
5223           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5224              to initialize VLAs will cause a proper error; avoid tree
5225              checking errors as well by setting a safe value.  */
5226           if (constructor_max_index
5227               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5228             constructor_max_index = build_int_cst (NULL_TREE, -1);
5229
5230           constructor_index
5231             = convert (bitsizetype,
5232                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5233         }
5234       else
5235         {
5236           constructor_index = bitsize_zero_node;
5237           constructor_max_index = NULL_TREE;
5238         }
5239
5240       constructor_unfilled_index = constructor_index;
5241     }
5242   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5243     {
5244       /* Vectors are like simple fixed-size arrays.  */
5245       constructor_max_index =
5246         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5247       constructor_index = bitsize_zero_node;
5248       constructor_unfilled_index = constructor_index;
5249     }
5250   else
5251     {
5252       /* Handle the case of int x = {5}; */
5253       constructor_fields = constructor_type;
5254       constructor_unfilled_fields = constructor_type;
5255     }
5256 }
5257 \f
5258 /* Push down into a subobject, for initialization.
5259    If this is for an explicit set of braces, IMPLICIT is 0.
5260    If it is because the next element belongs at a lower level,
5261    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5262
5263 void
5264 push_init_level (int implicit)
5265 {
5266   struct constructor_stack *p;
5267   tree value = NULL_TREE;
5268
5269   /* If we've exhausted any levels that didn't have braces,
5270      pop them now.  If implicit == 1, this will have been done in
5271      process_init_element; do not repeat it here because in the case
5272      of excess initializers for an empty aggregate this leads to an
5273      infinite cycle of popping a level and immediately recreating
5274      it.  */
5275   if (implicit != 1)
5276     {
5277       while (constructor_stack->implicit)
5278         {
5279           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5280                || TREE_CODE (constructor_type) == UNION_TYPE)
5281               && constructor_fields == 0)
5282             process_init_element (pop_init_level (1));
5283           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5284                    && constructor_max_index
5285                    && tree_int_cst_lt (constructor_max_index,
5286                                        constructor_index))
5287             process_init_element (pop_init_level (1));
5288           else
5289             break;
5290         }
5291     }
5292
5293   /* Unless this is an explicit brace, we need to preserve previous
5294      content if any.  */
5295   if (implicit)
5296     {
5297       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5298            || TREE_CODE (constructor_type) == UNION_TYPE)
5299           && constructor_fields)
5300         value = find_init_member (constructor_fields);
5301       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5302         value = find_init_member (constructor_index);
5303     }
5304
5305   p = XNEW (struct constructor_stack);
5306   p->type = constructor_type;
5307   p->fields = constructor_fields;
5308   p->index = constructor_index;
5309   p->max_index = constructor_max_index;
5310   p->unfilled_index = constructor_unfilled_index;
5311   p->unfilled_fields = constructor_unfilled_fields;
5312   p->bit_index = constructor_bit_index;
5313   p->elements = constructor_elements;
5314   p->constant = constructor_constant;
5315   p->simple = constructor_simple;
5316   p->erroneous = constructor_erroneous;
5317   p->pending_elts = constructor_pending_elts;
5318   p->depth = constructor_depth;
5319   p->replacement_value.value = 0;
5320   p->replacement_value.original_code = ERROR_MARK;
5321   p->implicit = implicit;
5322   p->outer = 0;
5323   p->incremental = constructor_incremental;
5324   p->designated = constructor_designated;
5325   p->next = constructor_stack;
5326   p->range_stack = 0;
5327   constructor_stack = p;
5328
5329   constructor_constant = 1;
5330   constructor_simple = 1;
5331   constructor_depth = SPELLING_DEPTH ();
5332   constructor_elements = 0;
5333   constructor_incremental = 1;
5334   constructor_designated = 0;
5335   constructor_pending_elts = 0;
5336   if (!implicit)
5337     {
5338       p->range_stack = constructor_range_stack;
5339       constructor_range_stack = 0;
5340       designator_depth = 0;
5341       designator_erroneous = 0;
5342     }
5343
5344   /* Don't die if an entire brace-pair level is superfluous
5345      in the containing level.  */
5346   if (constructor_type == 0)
5347     ;
5348   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5349            || TREE_CODE (constructor_type) == UNION_TYPE)
5350     {
5351       /* Don't die if there are extra init elts at the end.  */
5352       if (constructor_fields == 0)
5353         constructor_type = 0;
5354       else
5355         {
5356           constructor_type = TREE_TYPE (constructor_fields);
5357           push_member_name (constructor_fields);
5358           constructor_depth++;
5359         }
5360     }
5361   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5362     {
5363       constructor_type = TREE_TYPE (constructor_type);
5364       push_array_bounds (tree_low_cst (constructor_index, 1));
5365       constructor_depth++;
5366     }
5367
5368   if (constructor_type == 0)
5369     {
5370       error_init ("extra brace group at end of initializer");
5371       constructor_fields = 0;
5372       constructor_unfilled_fields = 0;
5373       return;
5374     }
5375
5376   if (value && TREE_CODE (value) == CONSTRUCTOR)
5377     {
5378       constructor_constant = TREE_CONSTANT (value);
5379       constructor_simple = TREE_STATIC (value);
5380       constructor_elements = CONSTRUCTOR_ELTS (value);
5381       if (!VEC_empty (constructor_elt, constructor_elements)
5382           && (TREE_CODE (constructor_type) == RECORD_TYPE
5383               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5384         set_nonincremental_init ();
5385     }
5386
5387   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5388     {
5389       missing_braces_mentioned = 1;
5390       warning_init ("missing braces around initializer");
5391     }
5392
5393   if (TREE_CODE (constructor_type) == RECORD_TYPE
5394            || TREE_CODE (constructor_type) == UNION_TYPE)
5395     {
5396       constructor_fields = TYPE_FIELDS (constructor_type);
5397       /* Skip any nameless bit fields at the beginning.  */
5398       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5399              && DECL_NAME (constructor_fields) == 0)
5400         constructor_fields = TREE_CHAIN (constructor_fields);
5401
5402       constructor_unfilled_fields = constructor_fields;
5403       constructor_bit_index = bitsize_zero_node;
5404     }
5405   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5406     {
5407       /* Vectors are like simple fixed-size arrays.  */
5408       constructor_max_index =
5409         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5410       constructor_index = convert (bitsizetype, integer_zero_node);
5411       constructor_unfilled_index = constructor_index;
5412     }
5413   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5414     {
5415       if (TYPE_DOMAIN (constructor_type))
5416         {
5417           constructor_max_index
5418             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5419
5420           /* Detect non-empty initializations of zero-length arrays.  */
5421           if (constructor_max_index == NULL_TREE
5422               && TYPE_SIZE (constructor_type))
5423             constructor_max_index = build_int_cst (NULL_TREE, -1);
5424
5425           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5426              to initialize VLAs will cause a proper error; avoid tree
5427              checking errors as well by setting a safe value.  */
5428           if (constructor_max_index
5429               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5430             constructor_max_index = build_int_cst (NULL_TREE, -1);
5431
5432           constructor_index
5433             = convert (bitsizetype,
5434                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5435         }
5436       else
5437         constructor_index = bitsize_zero_node;
5438
5439       constructor_unfilled_index = constructor_index;
5440       if (value && TREE_CODE (value) == STRING_CST)
5441         {
5442           /* We need to split the char/wchar array into individual
5443              characters, so that we don't have to special case it
5444              everywhere.  */
5445           set_nonincremental_init_from_string (value);
5446         }
5447     }
5448   else
5449     {
5450       if (constructor_type != error_mark_node)
5451         warning_init ("braces around scalar initializer");
5452       constructor_fields = constructor_type;
5453       constructor_unfilled_fields = constructor_type;
5454     }
5455 }
5456
5457 /* At the end of an implicit or explicit brace level,
5458    finish up that level of constructor.  If a single expression
5459    with redundant braces initialized that level, return the
5460    c_expr structure for that expression.  Otherwise, the original_code
5461    element is set to ERROR_MARK.
5462    If we were outputting the elements as they are read, return 0 as the value
5463    from inner levels (process_init_element ignores that),
5464    but return error_mark_node as the value from the outermost level
5465    (that's what we want to put in DECL_INITIAL).
5466    Otherwise, return a CONSTRUCTOR expression as the value.  */
5467
5468 struct c_expr
5469 pop_init_level (int implicit)
5470 {
5471   struct constructor_stack *p;
5472   struct c_expr ret;
5473   ret.value = 0;
5474   ret.original_code = ERROR_MARK;
5475
5476   if (implicit == 0)
5477     {
5478       /* When we come to an explicit close brace,
5479          pop any inner levels that didn't have explicit braces.  */
5480       while (constructor_stack->implicit)
5481         process_init_element (pop_init_level (1));
5482
5483       gcc_assert (!constructor_range_stack);
5484     }
5485
5486   /* Now output all pending elements.  */
5487   constructor_incremental = 1;
5488   output_pending_init_elements (1);
5489
5490   p = constructor_stack;
5491
5492   /* Error for initializing a flexible array member, or a zero-length
5493      array member in an inappropriate context.  */
5494   if (constructor_type && constructor_fields
5495       && TREE_CODE (constructor_type) == ARRAY_TYPE
5496       && TYPE_DOMAIN (constructor_type)
5497       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5498     {
5499       /* Silently discard empty initializations.  The parser will
5500          already have pedwarned for empty brackets.  */
5501       if (integer_zerop (constructor_unfilled_index))
5502         constructor_type = NULL_TREE;
5503       else
5504         {
5505           gcc_assert (!TYPE_SIZE (constructor_type));
5506
5507           if (constructor_depth > 2)
5508             error_init ("initialization of flexible array member in a nested context");
5509           else if (pedantic)
5510             pedwarn_init ("initialization of a flexible array member");
5511
5512           /* We have already issued an error message for the existence
5513              of a flexible array member not at the end of the structure.
5514              Discard the initializer so that we do not die later.  */
5515           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5516             constructor_type = NULL_TREE;
5517         }
5518     }
5519
5520   /* Warn when some struct elements are implicitly initialized to zero.  */
5521   if (warn_missing_field_initializers
5522       && constructor_type
5523       && TREE_CODE (constructor_type) == RECORD_TYPE
5524       && constructor_unfilled_fields)
5525     {
5526         /* Do not warn for flexible array members or zero-length arrays.  */
5527         while (constructor_unfilled_fields
5528                && (!DECL_SIZE (constructor_unfilled_fields)
5529                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5530           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5531
5532         /* Do not warn if this level of the initializer uses member
5533            designators; it is likely to be deliberate.  */
5534         if (constructor_unfilled_fields && !constructor_designated)
5535           {
5536             push_member_name (constructor_unfilled_fields);
5537             warning_init ("missing initializer");
5538             RESTORE_SPELLING_DEPTH (constructor_depth);
5539           }
5540     }
5541
5542   /* Pad out the end of the structure.  */
5543   if (p->replacement_value.value)
5544     /* If this closes a superfluous brace pair,
5545        just pass out the element between them.  */
5546     ret = p->replacement_value;
5547   else if (constructor_type == 0)
5548     ;
5549   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5550            && TREE_CODE (constructor_type) != UNION_TYPE
5551            && TREE_CODE (constructor_type) != ARRAY_TYPE
5552            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5553     {
5554       /* A nonincremental scalar initializer--just return
5555          the element, after verifying there is just one.  */
5556       if (VEC_empty (constructor_elt,constructor_elements))
5557         {
5558           if (!constructor_erroneous)
5559             error_init ("empty scalar initializer");
5560           ret.value = error_mark_node;
5561         }
5562       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5563         {
5564           error_init ("extra elements in scalar initializer");
5565           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5566         }
5567       else
5568         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5569     }
5570   else
5571     {
5572       if (constructor_erroneous)
5573         ret.value = error_mark_node;
5574       else
5575         {
5576           ret.value = build_constructor (constructor_type,
5577                                          constructor_elements);
5578           if (constructor_constant)
5579             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5580           if (constructor_constant && constructor_simple)
5581             TREE_STATIC (ret.value) = 1;
5582         }
5583     }
5584
5585   constructor_type = p->type;
5586   constructor_fields = p->fields;
5587   constructor_index = p->index;
5588   constructor_max_index = p->max_index;
5589   constructor_unfilled_index = p->unfilled_index;
5590   constructor_unfilled_fields = p->unfilled_fields;
5591   constructor_bit_index = p->bit_index;
5592   constructor_elements = p->elements;
5593   constructor_constant = p->constant;
5594   constructor_simple = p->simple;
5595   constructor_erroneous = p->erroneous;
5596   constructor_incremental = p->incremental;
5597   constructor_designated = p->designated;
5598   constructor_pending_elts = p->pending_elts;
5599   constructor_depth = p->depth;
5600   if (!p->implicit)
5601     constructor_range_stack = p->range_stack;
5602   RESTORE_SPELLING_DEPTH (constructor_depth);
5603
5604   constructor_stack = p->next;
5605   free (p);
5606
5607   if (ret.value == 0 && constructor_stack == 0)
5608     ret.value = error_mark_node;
5609   return ret;
5610 }
5611
5612 /* Common handling for both array range and field name designators.
5613    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5614
5615 static int
5616 set_designator (int array)
5617 {
5618   tree subtype;
5619   enum tree_code subcode;
5620
5621   /* Don't die if an entire brace-pair level is superfluous
5622      in the containing level.  */
5623   if (constructor_type == 0)
5624     return 1;
5625
5626   /* If there were errors in this designator list already, bail out
5627      silently.  */
5628   if (designator_erroneous)
5629     return 1;
5630
5631   if (!designator_depth)
5632     {
5633       gcc_assert (!constructor_range_stack);
5634
5635       /* Designator list starts at the level of closest explicit
5636          braces.  */
5637       while (constructor_stack->implicit)
5638         process_init_element (pop_init_level (1));
5639       constructor_designated = 1;
5640       return 0;
5641     }
5642
5643   switch (TREE_CODE (constructor_type))
5644     {
5645     case  RECORD_TYPE:
5646     case  UNION_TYPE:
5647       subtype = TREE_TYPE (constructor_fields);
5648       if (subtype != error_mark_node)
5649         subtype = TYPE_MAIN_VARIANT (subtype);
5650       break;
5651     case ARRAY_TYPE:
5652       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5653       break;
5654     default:
5655       gcc_unreachable ();
5656     }
5657
5658   subcode = TREE_CODE (subtype);
5659   if (array && subcode != ARRAY_TYPE)
5660     {
5661       error_init ("array index in non-array initializer");
5662       return 1;
5663     }
5664   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5665     {
5666       error_init ("field name not in record or union initializer");
5667       return 1;
5668     }
5669
5670   constructor_designated = 1;
5671   push_init_level (2);
5672   return 0;
5673 }
5674
5675 /* If there are range designators in designator list, push a new designator
5676    to constructor_range_stack.  RANGE_END is end of such stack range or
5677    NULL_TREE if there is no range designator at this level.  */
5678
5679 static void
5680 push_range_stack (tree range_end)
5681 {
5682   struct constructor_range_stack *p;
5683
5684   p = GGC_NEW (struct constructor_range_stack);
5685   p->prev = constructor_range_stack;
5686   p->next = 0;
5687   p->fields = constructor_fields;
5688   p->range_start = constructor_index;
5689   p->index = constructor_index;
5690   p->stack = constructor_stack;
5691   p->range_end = range_end;
5692   if (constructor_range_stack)
5693     constructor_range_stack->next = p;
5694   constructor_range_stack = p;
5695 }
5696
5697 /* Within an array initializer, specify the next index to be initialized.
5698    FIRST is that index.  If LAST is nonzero, then initialize a range
5699    of indices, running from FIRST through LAST.  */
5700
5701 void
5702 set_init_index (tree first, tree last)
5703 {
5704   if (set_designator (1))
5705     return;
5706
5707   designator_erroneous = 1;
5708
5709   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5710       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5711     {
5712       error_init ("array index in initializer not of integer type");
5713       return;
5714     }
5715
5716   if (TREE_CODE (first) != INTEGER_CST)
5717     error_init ("nonconstant array index in initializer");
5718   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5719     error_init ("nonconstant array index in initializer");
5720   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5721     error_init ("array index in non-array initializer");
5722   else if (tree_int_cst_sgn (first) == -1)
5723     error_init ("array index in initializer exceeds array bounds");
5724   else if (constructor_max_index
5725            && tree_int_cst_lt (constructor_max_index, first))
5726     error_init ("array index in initializer exceeds array bounds");
5727   else
5728     {
5729       constructor_index = convert (bitsizetype, first);
5730
5731       if (last)
5732         {
5733           if (tree_int_cst_equal (first, last))
5734             last = 0;
5735           else if (tree_int_cst_lt (last, first))
5736             {
5737               error_init ("empty index range in initializer");
5738               last = 0;
5739             }
5740           else
5741             {
5742               last = convert (bitsizetype, last);
5743               if (constructor_max_index != 0
5744                   && tree_int_cst_lt (constructor_max_index, last))
5745                 {
5746                   error_init ("array index range in initializer exceeds array bounds");
5747                   last = 0;
5748                 }
5749             }
5750         }
5751
5752       designator_depth++;
5753       designator_erroneous = 0;
5754       if (constructor_range_stack || last)
5755         push_range_stack (last);
5756     }
5757 }
5758
5759 /* Within a struct initializer, specify the next field to be initialized.  */
5760
5761 void
5762 set_init_label (tree fieldname)
5763 {
5764   tree tail;
5765
5766   if (set_designator (0))
5767     return;
5768
5769   designator_erroneous = 1;
5770
5771   if (TREE_CODE (constructor_type) != RECORD_TYPE
5772       && TREE_CODE (constructor_type) != UNION_TYPE)
5773     {
5774       error_init ("field name not in record or union initializer");
5775       return;
5776     }
5777
5778   for (tail = TYPE_FIELDS (constructor_type); tail;
5779        tail = TREE_CHAIN (tail))
5780     {
5781       if (DECL_NAME (tail) == fieldname)
5782         break;
5783     }
5784
5785   if (tail == 0)
5786     error ("unknown field %qE specified in initializer", fieldname);
5787   else
5788     {
5789       constructor_fields = tail;
5790       designator_depth++;
5791       designator_erroneous = 0;
5792       if (constructor_range_stack)
5793         push_range_stack (NULL_TREE);
5794     }
5795 }
5796 \f
5797 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5798    identifies the initializer, either array index or field in a structure.
5799    VALUE is the value of that index or field.  */
5800
5801 static void
5802 add_pending_init (tree purpose, tree value)
5803 {
5804   struct init_node *p, **q, *r;
5805
5806   q = &constructor_pending_elts;
5807   p = 0;
5808
5809   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5810     {
5811       while (*q != 0)
5812         {
5813           p = *q;
5814           if (tree_int_cst_lt (purpose, p->purpose))
5815             q = &p->left;
5816           else if (tree_int_cst_lt (p->purpose, purpose))
5817             q = &p->right;
5818           else
5819             {
5820               if (TREE_SIDE_EFFECTS (p->value))
5821                 warning_init ("initialized field with side-effects overwritten");
5822               else if (warn_override_init)
5823                 warning_init ("initialized field overwritten");
5824               p->value = value;
5825               return;
5826             }
5827         }
5828     }
5829   else
5830     {
5831       tree bitpos;
5832
5833       bitpos = bit_position (purpose);
5834       while (*q != NULL)
5835         {
5836           p = *q;
5837           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5838             q = &p->left;
5839           else if (p->purpose != purpose)
5840             q = &p->right;
5841           else
5842             {
5843               if (TREE_SIDE_EFFECTS (p->value))
5844                 warning_init ("initialized field with side-effects overwritten");
5845               else if (warn_override_init)
5846                 warning_init ("initialized field overwritten");
5847               p->value = value;
5848               return;
5849             }
5850         }
5851     }
5852
5853   r = GGC_NEW (struct init_node);
5854   r->purpose = purpose;
5855   r->value = value;
5856
5857   *q = r;
5858   r->parent = p;
5859   r->left = 0;
5860   r->right = 0;
5861   r->balance = 0;
5862
5863   while (p)
5864     {
5865       struct init_node *s;
5866
5867       if (r == p->left)
5868         {
5869           if (p->balance == 0)
5870             p->balance = -1;
5871           else if (p->balance < 0)
5872             {
5873               if (r->balance < 0)
5874                 {
5875                   /* L rotation.  */
5876                   p->left = r->right;
5877                   if (p->left)
5878                     p->left->parent = p;
5879                   r->right = p;
5880
5881                   p->balance = 0;
5882                   r->balance = 0;
5883
5884                   s = p->parent;
5885                   p->parent = r;
5886                   r->parent = s;
5887                   if (s)
5888                     {
5889                       if (s->left == p)
5890                         s->left = r;
5891                       else
5892                         s->right = r;
5893                     }
5894                   else
5895                     constructor_pending_elts = r;
5896                 }
5897               else
5898                 {
5899                   /* LR rotation.  */
5900                   struct init_node *t = r->right;
5901
5902                   r->right = t->left;
5903                   if (r->right)
5904                     r->right->parent = r;
5905                   t->left = r;
5906
5907                   p->left = t->right;
5908                   if (p->left)
5909                     p->left->parent = p;
5910                   t->right = p;
5911
5912                   p->balance = t->balance < 0;
5913                   r->balance = -(t->balance > 0);
5914                   t->balance = 0;
5915
5916                   s = p->parent;
5917                   p->parent = t;
5918                   r->parent = t;
5919                   t->parent = s;
5920                   if (s)
5921                     {
5922                       if (s->left == p)
5923                         s->left = t;
5924                       else
5925                         s->right = t;
5926                     }
5927                   else
5928                     constructor_pending_elts = t;
5929                 }
5930               break;
5931             }
5932           else
5933             {
5934               /* p->balance == +1; growth of left side balances the node.  */
5935               p->balance = 0;
5936               break;
5937             }
5938         }
5939       else /* r == p->right */
5940         {
5941           if (p->balance == 0)
5942             /* Growth propagation from right side.  */
5943             p->balance++;
5944           else if (p->balance > 0)
5945             {
5946               if (r->balance > 0)
5947                 {
5948                   /* R rotation.  */
5949                   p->right = r->left;
5950                   if (p->right)
5951                     p->right->parent = p;
5952                   r->left = p;
5953
5954                   p->balance = 0;
5955                   r->balance = 0;
5956
5957                   s = p->parent;
5958                   p->parent = r;
5959                   r->parent = s;
5960                   if (s)
5961                     {
5962                       if (s->left == p)
5963                         s->left = r;
5964                       else
5965                         s->right = r;
5966                     }
5967                   else
5968                     constructor_pending_elts = r;
5969                 }
5970               else /* r->balance == -1 */
5971                 {
5972                   /* RL rotation */
5973                   struct init_node *t = r->left;
5974
5975                   r->left = t->right;
5976                   if (r->left)
5977                     r->left->parent = r;
5978                   t->right = r;
5979
5980                   p->right = t->left;
5981                   if (p->right)
5982                     p->right->parent = p;
5983                   t->left = p;
5984
5985                   r->balance = (t->balance < 0);
5986                   p->balance = -(t->balance > 0);
5987                   t->balance = 0;
5988
5989                   s = p->parent;
5990                   p->parent = t;
5991                   r->parent = t;
5992                   t->parent = s;
5993                   if (s)
5994                     {
5995                       if (s->left == p)
5996                         s->left = t;
5997                       else
5998                         s->right = t;
5999                     }
6000                   else
6001                     constructor_pending_elts = t;
6002                 }
6003               break;
6004             }
6005           else
6006             {
6007               /* p->balance == -1; growth of right side balances the node.  */
6008               p->balance = 0;
6009               break;
6010             }
6011         }
6012
6013       r = p;
6014       p = p->parent;
6015     }
6016 }
6017
6018 /* Build AVL tree from a sorted chain.  */
6019
6020 static void
6021 set_nonincremental_init (void)
6022 {
6023   unsigned HOST_WIDE_INT ix;
6024   tree index, value;
6025
6026   if (TREE_CODE (constructor_type) != RECORD_TYPE
6027       && TREE_CODE (constructor_type) != ARRAY_TYPE)
6028     return;
6029
6030   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
6031     add_pending_init (index, value);
6032   constructor_elements = 0;
6033   if (TREE_CODE (constructor_type) == RECORD_TYPE)
6034     {
6035       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
6036       /* Skip any nameless bit fields at the beginning.  */
6037       while (constructor_unfilled_fields != 0
6038              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6039              && DECL_NAME (constructor_unfilled_fields) == 0)
6040         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
6041
6042     }
6043   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6044     {
6045       if (TYPE_DOMAIN (constructor_type))
6046         constructor_unfilled_index
6047             = convert (bitsizetype,
6048                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
6049       else
6050         constructor_unfilled_index = bitsize_zero_node;
6051     }
6052   constructor_incremental = 0;
6053 }
6054
6055 /* Build AVL tree from a string constant.  */
6056
6057 static void
6058 set_nonincremental_init_from_string (tree str)
6059 {
6060   tree value, purpose, type;
6061   HOST_WIDE_INT val[2];
6062   const char *p, *end;
6063   int byte, wchar_bytes, charwidth, bitpos;
6064
6065   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
6066
6067   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6068       == TYPE_PRECISION (char_type_node))
6069     wchar_bytes = 1;
6070   else
6071     {
6072       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
6073                   == TYPE_PRECISION (wchar_type_node));
6074       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
6075     }
6076   charwidth = TYPE_PRECISION (char_type_node);
6077   type = TREE_TYPE (constructor_type);
6078   p = TREE_STRING_POINTER (str);
6079   end = p + TREE_STRING_LENGTH (str);
6080
6081   for (purpose = bitsize_zero_node;
6082        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
6083        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
6084     {
6085       if (wchar_bytes == 1)
6086         {
6087           val[1] = (unsigned char) *p++;
6088           val[0] = 0;
6089         }
6090       else
6091         {
6092           val[0] = 0;
6093           val[1] = 0;
6094           for (byte = 0; byte < wchar_bytes; byte++)
6095             {
6096               if (BYTES_BIG_ENDIAN)
6097                 bitpos = (wchar_bytes - byte - 1) * charwidth;
6098               else
6099                 bitpos = byte * charwidth;
6100               val[bitpos < HOST_BITS_PER_WIDE_INT]
6101                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
6102                    << (bitpos % HOST_BITS_PER_WIDE_INT);
6103             }
6104         }
6105
6106       if (!TYPE_UNSIGNED (type))
6107         {
6108           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
6109           if (bitpos < HOST_BITS_PER_WIDE_INT)
6110             {
6111               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
6112                 {
6113                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
6114                   val[0] = -1;
6115                 }
6116             }
6117           else if (bitpos == HOST_BITS_PER_WIDE_INT)
6118             {
6119               if (val[1] < 0)
6120                 val[0] = -1;
6121             }
6122           else if (val[0] & (((HOST_WIDE_INT) 1)
6123                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
6124             val[0] |= ((HOST_WIDE_INT) -1)
6125                       << (bitpos - HOST_BITS_PER_WIDE_INT);
6126         }
6127
6128       value = build_int_cst_wide (type, val[1], val[0]);
6129       add_pending_init (purpose, value);
6130     }
6131
6132   constructor_incremental = 0;
6133 }
6134
6135 /* Return value of FIELD in pending initializer or zero if the field was
6136    not initialized yet.  */
6137
6138 static tree
6139 find_init_member (tree field)
6140 {
6141   struct init_node *p;
6142
6143   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6144     {
6145       if (constructor_incremental
6146           && tree_int_cst_lt (field, constructor_unfilled_index))
6147         set_nonincremental_init ();
6148
6149       p = constructor_pending_elts;
6150       while (p)
6151         {
6152           if (tree_int_cst_lt (field, p->purpose))
6153             p = p->left;
6154           else if (tree_int_cst_lt (p->purpose, field))
6155             p = p->right;
6156           else
6157             return p->value;
6158         }
6159     }
6160   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6161     {
6162       tree bitpos = bit_position (field);
6163
6164       if (constructor_incremental
6165           && (!constructor_unfilled_fields
6166               || tree_int_cst_lt (bitpos,
6167                                   bit_position (constructor_unfilled_fields))))
6168         set_nonincremental_init ();
6169
6170       p = constructor_pending_elts;
6171       while (p)
6172         {
6173           if (field == p->purpose)
6174             return p->value;
6175           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
6176             p = p->left;
6177           else
6178             p = p->right;
6179         }
6180     }
6181   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6182     {
6183       if (!VEC_empty (constructor_elt, constructor_elements)
6184           && (VEC_last (constructor_elt, constructor_elements)->index
6185               == field))
6186         return VEC_last (constructor_elt, constructor_elements)->value;
6187     }
6188   return 0;
6189 }
6190
6191 /* "Output" the next constructor element.
6192    At top level, really output it to assembler code now.
6193    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6194    TYPE is the data type that the containing data type wants here.
6195    FIELD is the field (a FIELD_DECL) or the index that this element fills.
6196    If VALUE is a string constant, STRICT_STRING is true if it is
6197    unparenthesized or we should not warn here for it being parenthesized.
6198    For other types of VALUE, STRICT_STRING is not used.
6199
6200    PENDING if non-nil means output pending elements that belong
6201    right after this element.  (PENDING is normally 1;
6202    it is 0 while outputting pending elements, to avoid recursion.)  */
6203
6204 static void
6205 output_init_element (tree value, bool strict_string, tree type, tree field,
6206                      int pending)
6207 {
6208   constructor_elt *celt;
6209
6210   if (type == error_mark_node || value == error_mark_node)
6211     {
6212       constructor_erroneous = 1;
6213       return;
6214     }
6215   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
6216       && (TREE_CODE (value) == STRING_CST
6217           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
6218       && !(TREE_CODE (value) == STRING_CST
6219            && TREE_CODE (type) == ARRAY_TYPE
6220            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
6221       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
6222                      TYPE_MAIN_VARIANT (type)))
6223     value = array_to_pointer_conversion (value);
6224
6225   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6226       && require_constant_value && !flag_isoc99 && pending)
6227     {
6228       /* As an extension, allow initializing objects with static storage
6229          duration with compound literals (which are then treated just as
6230          the brace enclosed list they contain).  */
6231       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6232       value = DECL_INITIAL (decl);
6233     }
6234
6235   if (value == error_mark_node)
6236     constructor_erroneous = 1;
6237   else if (!TREE_CONSTANT (value))
6238     constructor_constant = 0;
6239   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6240            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6241                 || TREE_CODE (constructor_type) == UNION_TYPE)
6242                && DECL_C_BIT_FIELD (field)
6243                && TREE_CODE (value) != INTEGER_CST))
6244     constructor_simple = 0;
6245
6246   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6247     {
6248       if (require_constant_value)
6249         {
6250           error_init ("initializer element is not constant");
6251           value = error_mark_node;
6252         }
6253       else if (require_constant_elements)
6254         pedwarn ("initializer element is not computable at load time");
6255     }
6256
6257   /* If this field is empty (and not at the end of structure),
6258      don't do anything other than checking the initializer.  */
6259   if (field
6260       && (TREE_TYPE (field) == error_mark_node
6261           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6262               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6263               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6264                   || TREE_CHAIN (field)))))
6265     return;
6266
6267   value = digest_init (type, value, strict_string, require_constant_value);
6268   if (value == error_mark_node)
6269     {
6270       constructor_erroneous = 1;
6271       return;
6272     }
6273
6274   /* If this element doesn't come next in sequence,
6275      put it on constructor_pending_elts.  */
6276   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6277       && (!constructor_incremental
6278           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6279     {
6280       if (constructor_incremental
6281           && tree_int_cst_lt (field, constructor_unfilled_index))
6282         set_nonincremental_init ();
6283
6284       add_pending_init (field, value);
6285       return;
6286     }
6287   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6288            && (!constructor_incremental
6289                || field != constructor_unfilled_fields))
6290     {
6291       /* We do this for records but not for unions.  In a union,
6292          no matter which field is specified, it can be initialized
6293          right away since it starts at the beginning of the union.  */
6294       if (constructor_incremental)
6295         {
6296           if (!constructor_unfilled_fields)
6297             set_nonincremental_init ();
6298           else
6299             {
6300               tree bitpos, unfillpos;
6301
6302               bitpos = bit_position (field);
6303               unfillpos = bit_position (constructor_unfilled_fields);
6304
6305               if (tree_int_cst_lt (bitpos, unfillpos))
6306                 set_nonincremental_init ();
6307             }
6308         }
6309
6310       add_pending_init (field, value);
6311       return;
6312     }
6313   else if (TREE_CODE (constructor_type) == UNION_TYPE
6314            && !VEC_empty (constructor_elt, constructor_elements))
6315     {
6316       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6317                                        constructor_elements)->value))
6318         warning_init ("initialized field with side-effects overwritten");
6319       else if (warn_override_init)
6320         warning_init ("initialized field overwritten");
6321
6322       /* We can have just one union field set.  */
6323       constructor_elements = 0;
6324     }
6325
6326   /* Otherwise, output this element either to
6327      constructor_elements or to the assembler file.  */
6328
6329   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6330   celt->index = field;
6331   celt->value = value;
6332
6333   /* Advance the variable that indicates sequential elements output.  */
6334   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6335     constructor_unfilled_index
6336       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6337                     bitsize_one_node);
6338   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6339     {
6340       constructor_unfilled_fields
6341         = TREE_CHAIN (constructor_unfilled_fields);
6342
6343       /* Skip any nameless bit fields.  */
6344       while (constructor_unfilled_fields != 0
6345              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6346              && DECL_NAME (constructor_unfilled_fields) == 0)
6347         constructor_unfilled_fields =
6348           TREE_CHAIN (constructor_unfilled_fields);
6349     }
6350   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6351     constructor_unfilled_fields = 0;
6352
6353   /* Now output any pending elements which have become next.  */
6354   if (pending)
6355     output_pending_init_elements (0);
6356 }
6357
6358 /* Output any pending elements which have become next.
6359    As we output elements, constructor_unfilled_{fields,index}
6360    advances, which may cause other elements to become next;
6361    if so, they too are output.
6362
6363    If ALL is 0, we return when there are
6364    no more pending elements to output now.
6365
6366    If ALL is 1, we output space as necessary so that
6367    we can output all the pending elements.  */
6368
6369 static void
6370 output_pending_init_elements (int all)
6371 {
6372   struct init_node *elt = constructor_pending_elts;
6373   tree next;
6374
6375  retry:
6376
6377   /* Look through the whole pending tree.
6378      If we find an element that should be output now,
6379      output it.  Otherwise, set NEXT to the element
6380      that comes first among those still pending.  */
6381
6382   next = 0;
6383   while (elt)
6384     {
6385       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6386         {
6387           if (tree_int_cst_equal (elt->purpose,
6388                                   constructor_unfilled_index))
6389             output_init_element (elt->value, true,
6390                                  TREE_TYPE (constructor_type),
6391                                  constructor_unfilled_index, 0);
6392           else if (tree_int_cst_lt (constructor_unfilled_index,
6393                                     elt->purpose))
6394             {
6395               /* Advance to the next smaller node.  */
6396               if (elt->left)
6397                 elt = elt->left;
6398               else
6399                 {
6400                   /* We have reached the smallest node bigger than the
6401                      current unfilled index.  Fill the space first.  */
6402                   next = elt->purpose;
6403                   break;
6404                 }
6405             }
6406           else
6407             {
6408               /* Advance to the next bigger node.  */
6409               if (elt->right)
6410                 elt = elt->right;
6411               else
6412                 {
6413                   /* We have reached the biggest node in a subtree.  Find
6414                      the parent of it, which is the next bigger node.  */
6415                   while (elt->parent && elt->parent->right == elt)
6416                     elt = elt->parent;
6417                   elt = elt->parent;
6418                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6419                                               elt->purpose))
6420                     {
6421                       next = elt->purpose;
6422                       break;
6423                     }
6424                 }
6425             }
6426         }
6427       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6428                || TREE_CODE (constructor_type) == UNION_TYPE)
6429         {
6430           tree ctor_unfilled_bitpos, elt_bitpos;
6431
6432           /* If the current record is complete we are done.  */
6433           if (constructor_unfilled_fields == 0)
6434             break;
6435
6436           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6437           elt_bitpos = bit_position (elt->purpose);
6438           /* We can't compare fields here because there might be empty
6439              fields in between.  */
6440           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6441             {
6442               constructor_unfilled_fields = elt->purpose;
6443               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6444                                    elt->purpose, 0);
6445             }
6446           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6447             {
6448               /* Advance to the next smaller node.  */
6449               if (elt->left)
6450                 elt = elt->left;
6451               else
6452                 {
6453                   /* We have reached the smallest node bigger than the
6454                      current unfilled field.  Fill the space first.  */
6455                   next = elt->purpose;
6456                   break;
6457                 }
6458             }
6459           else
6460             {
6461               /* Advance to the next bigger node.  */
6462               if (elt->right)
6463                 elt = elt->right;
6464               else
6465                 {
6466                   /* We have reached the biggest node in a subtree.  Find
6467                      the parent of it, which is the next bigger node.  */
6468                   while (elt->parent && elt->parent->right == elt)
6469                     elt = elt->parent;
6470                   elt = elt->parent;
6471                   if (elt
6472                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6473                                            bit_position (elt->purpose))))
6474                     {
6475                       next = elt->purpose;
6476                       break;
6477                     }
6478                 }
6479             }
6480         }
6481     }
6482
6483   /* Ordinarily return, but not if we want to output all
6484      and there are elements left.  */
6485   if (!(all && next != 0))
6486     return;
6487
6488   /* If it's not incremental, just skip over the gap, so that after
6489      jumping to retry we will output the next successive element.  */
6490   if (TREE_CODE (constructor_type) == RECORD_TYPE
6491       || TREE_CODE (constructor_type) == UNION_TYPE)
6492     constructor_unfilled_fields = next;
6493   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6494     constructor_unfilled_index = next;
6495
6496   /* ELT now points to the node in the pending tree with the next
6497      initializer to output.  */
6498   goto retry;
6499 }
6500 \f
6501 /* Add one non-braced element to the current constructor level.
6502    This adjusts the current position within the constructor's type.
6503    This may also start or terminate implicit levels
6504    to handle a partly-braced initializer.
6505
6506    Once this has found the correct level for the new element,
6507    it calls output_init_element.  */
6508
6509 void
6510 process_init_element (struct c_expr value)
6511 {
6512   tree orig_value = value.value;
6513   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6514   bool strict_string = value.original_code == STRING_CST;
6515
6516   designator_depth = 0;
6517   designator_erroneous = 0;
6518
6519   /* Handle superfluous braces around string cst as in
6520      char x[] = {"foo"}; */
6521   if (string_flag
6522       && constructor_type
6523       && TREE_CODE (constructor_type) == ARRAY_TYPE
6524       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6525       && integer_zerop (constructor_unfilled_index))
6526     {
6527       if (constructor_stack->replacement_value.value)
6528         error_init ("excess elements in char array initializer");
6529       constructor_stack->replacement_value = value;
6530       return;
6531     }
6532
6533   if (constructor_stack->replacement_value.value != 0)
6534     {
6535       error_init ("excess elements in struct initializer");
6536       return;
6537     }
6538
6539   /* Ignore elements of a brace group if it is entirely superfluous
6540      and has already been diagnosed.  */
6541   if (constructor_type == 0)
6542     return;
6543
6544   /* If we've exhausted any levels that didn't have braces,
6545      pop them now.  */
6546   while (constructor_stack->implicit)
6547     {
6548       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6549            || TREE_CODE (constructor_type) == UNION_TYPE)
6550           && constructor_fields == 0)
6551         process_init_element (pop_init_level (1));
6552       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6553                && (constructor_max_index == 0
6554                    || tree_int_cst_lt (constructor_max_index,
6555                                        constructor_index)))
6556         process_init_element (pop_init_level (1));
6557       else
6558         break;
6559     }
6560
6561   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6562   if (constructor_range_stack)
6563     {
6564       /* If value is a compound literal and we'll be just using its
6565          content, don't put it into a SAVE_EXPR.  */
6566       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6567           || !require_constant_value
6568           || flag_isoc99)
6569         value.value = save_expr (value.value);
6570     }
6571
6572   while (1)
6573     {
6574       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6575         {
6576           tree fieldtype;
6577           enum tree_code fieldcode;
6578
6579           if (constructor_fields == 0)
6580             {
6581               pedwarn_init ("excess elements in struct initializer");
6582               break;
6583             }
6584
6585           fieldtype = TREE_TYPE (constructor_fields);
6586           if (fieldtype != error_mark_node)
6587             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6588           fieldcode = TREE_CODE (fieldtype);
6589
6590           /* Error for non-static initialization of a flexible array member.  */
6591           if (fieldcode == ARRAY_TYPE
6592               && !require_constant_value
6593               && TYPE_SIZE (fieldtype) == NULL_TREE
6594               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6595             {
6596               error_init ("non-static initialization of a flexible array member");
6597               break;
6598             }
6599
6600           /* Accept a string constant to initialize a subarray.  */
6601           if (value.value != 0
6602               && fieldcode == ARRAY_TYPE
6603               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6604               && string_flag)
6605             value.value = orig_value;
6606           /* Otherwise, if we have come to a subaggregate,
6607              and we don't have an element of its type, push into it.  */
6608           else if (value.value != 0
6609                    && value.value != error_mark_node
6610                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6611                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6612                        || fieldcode == UNION_TYPE))
6613             {
6614               push_init_level (1);
6615               continue;
6616             }
6617
6618           if (value.value)
6619             {
6620               push_member_name (constructor_fields);
6621               output_init_element (value.value, strict_string,
6622                                    fieldtype, constructor_fields, 1);
6623               RESTORE_SPELLING_DEPTH (constructor_depth);
6624             }
6625           else
6626             /* Do the bookkeeping for an element that was
6627                directly output as a constructor.  */
6628             {
6629               /* For a record, keep track of end position of last field.  */
6630               if (DECL_SIZE (constructor_fields))
6631                 constructor_bit_index
6632                   = size_binop (PLUS_EXPR,
6633                                 bit_position (constructor_fields),
6634                                 DECL_SIZE (constructor_fields));
6635
6636               /* If the current field was the first one not yet written out,
6637                  it isn't now, so update.  */
6638               if (constructor_unfilled_fields == constructor_fields)
6639                 {
6640                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6641                   /* Skip any nameless bit fields.  */
6642                   while (constructor_unfilled_fields != 0
6643                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6644                          && DECL_NAME (constructor_unfilled_fields) == 0)
6645                     constructor_unfilled_fields =
6646                       TREE_CHAIN (constructor_unfilled_fields);
6647                 }
6648             }
6649
6650           constructor_fields = TREE_CHAIN (constructor_fields);
6651           /* Skip any nameless bit fields at the beginning.  */
6652           while (constructor_fields != 0
6653                  && DECL_C_BIT_FIELD (constructor_fields)
6654                  && DECL_NAME (constructor_fields) == 0)
6655             constructor_fields = TREE_CHAIN (constructor_fields);
6656         }
6657       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6658         {
6659           tree fieldtype;
6660           enum tree_code fieldcode;
6661
6662           if (constructor_fields == 0)
6663             {
6664               pedwarn_init ("excess elements in union initializer");
6665               break;
6666             }
6667
6668           fieldtype = TREE_TYPE (constructor_fields);
6669           if (fieldtype != error_mark_node)
6670             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6671           fieldcode = TREE_CODE (fieldtype);
6672
6673           /* Warn that traditional C rejects initialization of unions.
6674              We skip the warning if the value is zero.  This is done
6675              under the assumption that the zero initializer in user
6676              code appears conditioned on e.g. __STDC__ to avoid
6677              "missing initializer" warnings and relies on default
6678              initialization to zero in the traditional C case.
6679              We also skip the warning if the initializer is designated,
6680              again on the assumption that this must be conditional on
6681              __STDC__ anyway (and we've already complained about the
6682              member-designator already).  */
6683           if (!in_system_header && !constructor_designated
6684               && !(value.value && (integer_zerop (value.value)
6685                                    || real_zerop (value.value))))
6686             warning (OPT_Wtraditional, "traditional C rejects initialization "
6687                      "of unions");
6688
6689           /* Accept a string constant to initialize a subarray.  */
6690           if (value.value != 0
6691               && fieldcode == ARRAY_TYPE
6692               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6693               && string_flag)
6694             value.value = orig_value;
6695           /* Otherwise, if we have come to a subaggregate,
6696              and we don't have an element of its type, push into it.  */
6697           else if (value.value != 0
6698                    && value.value != error_mark_node
6699                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6700                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6701                        || fieldcode == UNION_TYPE))
6702             {
6703               push_init_level (1);
6704               continue;
6705             }
6706
6707           if (value.value)
6708             {
6709               push_member_name (constructor_fields);
6710               output_init_element (value.value, strict_string,
6711                                    fieldtype, constructor_fields, 1);
6712               RESTORE_SPELLING_DEPTH (constructor_depth);
6713             }
6714           else
6715             /* Do the bookkeeping for an element that was
6716                directly output as a constructor.  */
6717             {
6718               constructor_bit_index = DECL_SIZE (constructor_fields);
6719               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6720             }
6721
6722           constructor_fields = 0;
6723         }
6724       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6725         {
6726           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6727           enum tree_code eltcode = TREE_CODE (elttype);
6728
6729           /* Accept a string constant to initialize a subarray.  */
6730           if (value.value != 0
6731               && eltcode == ARRAY_TYPE
6732               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6733               && string_flag)
6734             value.value = orig_value;
6735           /* Otherwise, if we have come to a subaggregate,
6736              and we don't have an element of its type, push into it.  */
6737           else if (value.value != 0
6738                    && value.value != error_mark_node
6739                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6740                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6741                        || eltcode == UNION_TYPE))
6742             {
6743               push_init_level (1);
6744               continue;
6745             }
6746
6747           if (constructor_max_index != 0
6748               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6749                   || integer_all_onesp (constructor_max_index)))
6750             {
6751               pedwarn_init ("excess elements in array initializer");
6752               break;
6753             }
6754
6755           /* Now output the actual element.  */
6756           if (value.value)
6757             {
6758               push_array_bounds (tree_low_cst (constructor_index, 1));
6759               output_init_element (value.value, strict_string,
6760                                    elttype, constructor_index, 1);
6761               RESTORE_SPELLING_DEPTH (constructor_depth);
6762             }
6763
6764           constructor_index
6765             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6766
6767           if (!value.value)
6768             /* If we are doing the bookkeeping for an element that was
6769                directly output as a constructor, we must update
6770                constructor_unfilled_index.  */
6771             constructor_unfilled_index = constructor_index;
6772         }
6773       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6774         {
6775           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6776
6777          /* Do a basic check of initializer size.  Note that vectors
6778             always have a fixed size derived from their type.  */
6779           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6780             {
6781               pedwarn_init ("excess elements in vector initializer");
6782               break;
6783             }
6784
6785           /* Now output the actual element.  */
6786           if (value.value)
6787             output_init_element (value.value, strict_string,
6788                                  elttype, constructor_index, 1);
6789
6790           constructor_index
6791             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6792
6793           if (!value.value)
6794             /* If we are doing the bookkeeping for an element that was
6795                directly output as a constructor, we must update
6796                constructor_unfilled_index.  */
6797             constructor_unfilled_index = constructor_index;
6798         }
6799
6800       /* Handle the sole element allowed in a braced initializer
6801          for a scalar variable.  */
6802       else if (constructor_type != error_mark_node
6803                && constructor_fields == 0)
6804         {
6805           pedwarn_init ("excess elements in scalar initializer");
6806           break;
6807         }
6808       else
6809         {
6810           if (value.value)
6811             output_init_element (value.value, strict_string,
6812                                  constructor_type, NULL_TREE, 1);
6813           constructor_fields = 0;
6814         }
6815
6816       /* Handle range initializers either at this level or anywhere higher
6817          in the designator stack.  */
6818       if (constructor_range_stack)
6819         {
6820           struct constructor_range_stack *p, *range_stack;
6821           int finish = 0;
6822
6823           range_stack = constructor_range_stack;
6824           constructor_range_stack = 0;
6825           while (constructor_stack != range_stack->stack)
6826             {
6827               gcc_assert (constructor_stack->implicit);
6828               process_init_element (pop_init_level (1));
6829             }
6830           for (p = range_stack;
6831                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6832                p = p->prev)
6833             {
6834               gcc_assert (constructor_stack->implicit);
6835               process_init_element (pop_init_level (1));
6836             }
6837
6838           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6839           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6840             finish = 1;
6841
6842           while (1)
6843             {
6844               constructor_index = p->index;
6845               constructor_fields = p->fields;
6846               if (finish && p->range_end && p->index == p->range_start)
6847                 {
6848                   finish = 0;
6849                   p->prev = 0;
6850                 }
6851               p = p->next;
6852               if (!p)
6853                 break;
6854               push_init_level (2);
6855               p->stack = constructor_stack;
6856               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6857                 p->index = p->range_start;
6858             }
6859
6860           if (!finish)
6861             constructor_range_stack = range_stack;
6862           continue;
6863         }
6864
6865       break;
6866     }
6867
6868   constructor_range_stack = 0;
6869 }
6870 \f
6871 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6872    (guaranteed to be 'volatile' or null) and ARGS (represented using
6873    an ASM_EXPR node).  */
6874 tree
6875 build_asm_stmt (tree cv_qualifier, tree args)
6876 {
6877   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6878     ASM_VOLATILE_P (args) = 1;
6879   return add_stmt (args);
6880 }
6881
6882 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6883    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6884    SIMPLE indicates whether there was anything at all after the
6885    string in the asm expression -- asm("blah") and asm("blah" : )
6886    are subtly different.  We use a ASM_EXPR node to represent this.  */
6887 tree
6888 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6889                 bool simple)
6890 {
6891   tree tail;
6892   tree args;
6893   int i;
6894   const char *constraint;
6895   const char **oconstraints;
6896   bool allows_mem, allows_reg, is_inout;
6897   int ninputs, noutputs;
6898
6899   ninputs = list_length (inputs);
6900   noutputs = list_length (outputs);
6901   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6902
6903   string = resolve_asm_operand_names (string, outputs, inputs);
6904
6905   /* Remove output conversions that change the type but not the mode.  */
6906   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6907     {
6908       tree output = TREE_VALUE (tail);
6909
6910       /* ??? Really, this should not be here.  Users should be using a
6911          proper lvalue, dammit.  But there's a long history of using casts
6912          in the output operands.  In cases like longlong.h, this becomes a
6913          primitive form of typechecking -- if the cast can be removed, then
6914          the output operand had a type of the proper width; otherwise we'll
6915          get an error.  Gross, but ...  */
6916       STRIP_NOPS (output);
6917
6918       if (!lvalue_or_else (output, lv_asm))
6919         output = error_mark_node;
6920
6921       if (output != error_mark_node
6922           && (TREE_READONLY (output)
6923               || TYPE_READONLY (TREE_TYPE (output))
6924               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6925                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6926                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6927         readonly_error (output, lv_asm);
6928
6929       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6930       oconstraints[i] = constraint;
6931
6932       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6933                                    &allows_mem, &allows_reg, &is_inout))
6934         {
6935           /* If the operand is going to end up in memory,
6936              mark it addressable.  */
6937           if (!allows_reg && !c_mark_addressable (output))
6938             output = error_mark_node;
6939         }
6940       else
6941         output = error_mark_node;
6942
6943       TREE_VALUE (tail) = output;
6944     }
6945
6946   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6947     {
6948       tree input;
6949
6950       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6951       input = TREE_VALUE (tail);
6952
6953       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6954                                   oconstraints, &allows_mem, &allows_reg))
6955         {
6956           /* If the operand is going to end up in memory,
6957              mark it addressable.  */
6958           if (!allows_reg && allows_mem)
6959             {
6960               /* Strip the nops as we allow this case.  FIXME, this really
6961                  should be rejected or made deprecated.  */
6962               STRIP_NOPS (input);
6963               if (!c_mark_addressable (input))
6964                 input = error_mark_node;
6965           }
6966         }
6967       else
6968         input = error_mark_node;
6969
6970       TREE_VALUE (tail) = input;
6971     }
6972
6973   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6974
6975   /* asm statements without outputs, including simple ones, are treated
6976      as volatile.  */
6977   ASM_INPUT_P (args) = simple;
6978   ASM_VOLATILE_P (args) = (noutputs == 0);
6979
6980   return args;
6981 }
6982 \f
6983 /* Generate a goto statement to LABEL.  */
6984
6985 tree
6986 c_finish_goto_label (tree label)
6987 {
6988   tree decl = lookup_label (label);
6989   if (!decl)
6990     return NULL_TREE;
6991
6992   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6993     {
6994       error ("jump into statement expression");
6995       return NULL_TREE;
6996     }
6997
6998   if (C_DECL_UNJUMPABLE_VM (decl))
6999     {
7000       error ("jump into scope of identifier with variably modified type");
7001       return NULL_TREE;
7002     }
7003
7004   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
7005     {
7006       /* No jump from outside this statement expression context, so
7007          record that there is a jump from within this context.  */
7008       struct c_label_list *nlist;
7009       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7010       nlist->next = label_context_stack_se->labels_used;
7011       nlist->label = decl;
7012       label_context_stack_se->labels_used = nlist;
7013     }
7014
7015   if (!C_DECL_UNDEFINABLE_VM (decl))
7016     {
7017       /* No jump from outside this context context of identifiers with
7018          variably modified type, so record that there is a jump from
7019          within this context.  */
7020       struct c_label_list *nlist;
7021       nlist = XOBNEW (&parser_obstack, struct c_label_list);
7022       nlist->next = label_context_stack_vm->labels_used;
7023       nlist->label = decl;
7024       label_context_stack_vm->labels_used = nlist;
7025     }
7026
7027   TREE_USED (decl) = 1;
7028   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
7029 }
7030
7031 /* Generate a computed goto statement to EXPR.  */
7032
7033 tree
7034 c_finish_goto_ptr (tree expr)
7035 {
7036   if (pedantic)
7037     pedwarn ("ISO C forbids %<goto *expr;%>");
7038   expr = convert (ptr_type_node, expr);
7039   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
7040 }
7041
7042 /* Generate a C `return' statement.  RETVAL is the expression for what
7043    to return, or a null pointer for `return;' with no value.  */
7044
7045 tree
7046 c_finish_return (tree retval)
7047 {
7048   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
7049   bool no_warning = false;
7050
7051   if (TREE_THIS_VOLATILE (current_function_decl))
7052     warning (0, "function declared %<noreturn%> has a %<return%> statement");
7053
7054   if (!retval)
7055     {
7056       current_function_returns_null = 1;
7057       if ((warn_return_type || flag_isoc99)
7058           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
7059         {
7060           pedwarn_c99 ("%<return%> with no value, in "
7061                        "function returning non-void");
7062           no_warning = true;
7063         }
7064     }
7065   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
7066     {
7067       current_function_returns_null = 1;
7068       if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
7069         pedwarn ("%<return%> with a value, in function returning void");
7070       else if (pedantic)
7071         pedwarn ("ISO C forbids %<return%> with expression, in function returning void");
7072     }
7073   else
7074     {
7075       tree t = convert_for_assignment (valtype, retval, ic_return,
7076                                        NULL_TREE, NULL_TREE, 0);
7077       tree res = DECL_RESULT (current_function_decl);
7078       tree inner;
7079
7080       current_function_returns_value = 1;
7081       if (t == error_mark_node)
7082         return NULL_TREE;
7083
7084       inner = t = convert (TREE_TYPE (res), t);
7085
7086       /* Strip any conversions, additions, and subtractions, and see if
7087          we are returning the address of a local variable.  Warn if so.  */
7088       while (1)
7089         {
7090           switch (TREE_CODE (inner))
7091             {
7092             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
7093             case PLUS_EXPR:
7094               inner = TREE_OPERAND (inner, 0);
7095               continue;
7096
7097             case MINUS_EXPR:
7098               /* If the second operand of the MINUS_EXPR has a pointer
7099                  type (or is converted from it), this may be valid, so
7100                  don't give a warning.  */
7101               {
7102                 tree op1 = TREE_OPERAND (inner, 1);
7103
7104                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
7105                        && (TREE_CODE (op1) == NOP_EXPR
7106                            || TREE_CODE (op1) == NON_LVALUE_EXPR
7107                            || TREE_CODE (op1) == CONVERT_EXPR))
7108                   op1 = TREE_OPERAND (op1, 0);
7109
7110                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
7111                   break;
7112
7113                 inner = TREE_OPERAND (inner, 0);
7114                 continue;
7115               }
7116
7117             case ADDR_EXPR:
7118               inner = TREE_OPERAND (inner, 0);
7119
7120               while (REFERENCE_CLASS_P (inner)
7121                      && TREE_CODE (inner) != INDIRECT_REF)
7122                 inner = TREE_OPERAND (inner, 0);
7123
7124               if (DECL_P (inner)
7125                   && !DECL_EXTERNAL (inner)
7126                   && !TREE_STATIC (inner)
7127                   && DECL_CONTEXT (inner) == current_function_decl)
7128                 warning (0, "function returns address of local variable");
7129               break;
7130
7131             default:
7132               break;
7133             }
7134
7135           break;
7136         }
7137
7138       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
7139     }
7140
7141   ret_stmt = build_stmt (RETURN_EXPR, retval);
7142   TREE_NO_WARNING (ret_stmt) |= no_warning;
7143   return add_stmt (ret_stmt);
7144 }
7145 \f
7146 struct c_switch {
7147   /* The SWITCH_EXPR being built.  */
7148   tree switch_expr;
7149
7150   /* The original type of the testing expression, i.e. before the
7151      default conversion is applied.  */
7152   tree orig_type;
7153
7154   /* A splay-tree mapping the low element of a case range to the high
7155      element, or NULL_TREE if there is no high element.  Used to
7156      determine whether or not a new case label duplicates an old case
7157      label.  We need a tree, rather than simply a hash table, because
7158      of the GNU case range extension.  */
7159   splay_tree cases;
7160
7161   /* Number of nested statement expressions within this switch
7162      statement; if nonzero, case and default labels may not
7163      appear.  */
7164   unsigned int blocked_stmt_expr;
7165
7166   /* Scope of outermost declarations of identifiers with variably
7167      modified type within this switch statement; if nonzero, case and
7168      default labels may not appear.  */
7169   unsigned int blocked_vm;
7170
7171   /* The next node on the stack.  */
7172   struct c_switch *next;
7173 };
7174
7175 /* A stack of the currently active switch statements.  The innermost
7176    switch statement is on the top of the stack.  There is no need to
7177    mark the stack for garbage collection because it is only active
7178    during the processing of the body of a function, and we never
7179    collect at that point.  */
7180
7181 struct c_switch *c_switch_stack;
7182
7183 /* Start a C switch statement, testing expression EXP.  Return the new
7184    SWITCH_EXPR.  */
7185
7186 tree
7187 c_start_case (tree exp)
7188 {
7189   tree orig_type = error_mark_node;
7190   struct c_switch *cs;
7191
7192   if (exp != error_mark_node)
7193     {
7194       orig_type = TREE_TYPE (exp);
7195
7196       if (!INTEGRAL_TYPE_P (orig_type))
7197         {
7198           if (orig_type != error_mark_node)
7199             {
7200               error ("switch quantity not an integer");
7201               orig_type = error_mark_node;
7202             }
7203           exp = integer_zero_node;
7204         }
7205       else
7206         {
7207           tree type = TYPE_MAIN_VARIANT (orig_type);
7208
7209           if (!in_system_header
7210               && (type == long_integer_type_node
7211                   || type == long_unsigned_type_node))
7212             warning (OPT_Wtraditional, "%<long%> switch expression not "
7213                      "converted to %<int%> in ISO C");
7214
7215           exp = default_conversion (exp);
7216         }
7217     }
7218
7219   /* Add this new SWITCH_EXPR to the stack.  */
7220   cs = XNEW (struct c_switch);
7221   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
7222   cs->orig_type = orig_type;
7223   cs->cases = splay_tree_new (case_compare, NULL, NULL);
7224   cs->blocked_stmt_expr = 0;
7225   cs->blocked_vm = 0;
7226   cs->next = c_switch_stack;
7227   c_switch_stack = cs;
7228
7229   return add_stmt (cs->switch_expr);
7230 }
7231
7232 /* Process a case label.  */
7233
7234 tree
7235 do_case (tree low_value, tree high_value)
7236 {
7237   tree label = NULL_TREE;
7238
7239   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7240       && !c_switch_stack->blocked_vm)
7241     {
7242       label = c_add_case_label (c_switch_stack->cases,
7243                                 SWITCH_COND (c_switch_stack->switch_expr),
7244                                 c_switch_stack->orig_type,
7245                                 low_value, high_value);
7246       if (label == error_mark_node)
7247         label = NULL_TREE;
7248     }
7249   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7250     {
7251       if (low_value)
7252         error ("case label in statement expression not containing "
7253                "enclosing switch statement");
7254       else
7255         error ("%<default%> label in statement expression not containing "
7256                "enclosing switch statement");
7257     }
7258   else if (c_switch_stack && c_switch_stack->blocked_vm)
7259     {
7260       if (low_value)
7261         error ("case label in scope of identifier with variably modified "
7262                "type not containing enclosing switch statement");
7263       else
7264         error ("%<default%> label in scope of identifier with variably "
7265                "modified type not containing enclosing switch statement");
7266     }
7267   else if (low_value)
7268     error ("case label not within a switch statement");
7269   else
7270     error ("%<default%> label not within a switch statement");
7271
7272   return label;
7273 }
7274
7275 /* Finish the switch statement.  */
7276
7277 void
7278 c_finish_case (tree body)
7279 {
7280   struct c_switch *cs = c_switch_stack;
7281   location_t switch_location;
7282
7283   SWITCH_BODY (cs->switch_expr) = body;
7284
7285   /* We must not be within a statement expression nested in the switch
7286      at this point; we might, however, be within the scope of an
7287      identifier with variably modified type nested in the switch.  */
7288   gcc_assert (!cs->blocked_stmt_expr);
7289
7290   /* Emit warnings as needed.  */
7291   if (EXPR_HAS_LOCATION (cs->switch_expr))
7292     switch_location = EXPR_LOCATION (cs->switch_expr);
7293   else
7294     switch_location = input_location;
7295   c_do_switch_warnings (cs->cases, switch_location,
7296                         TREE_TYPE (cs->switch_expr),
7297                         SWITCH_COND (cs->switch_expr));
7298
7299   /* Pop the stack.  */
7300   c_switch_stack = cs->next;
7301   splay_tree_delete (cs->cases);
7302   XDELETE (cs);
7303 }
7304 \f
7305 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7306    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7307    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7308    statement, and was not surrounded with parenthesis.  */
7309
7310 void
7311 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7312                   tree else_block, bool nested_if)
7313 {
7314   tree stmt;
7315
7316   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7317   if (warn_parentheses && nested_if && else_block == NULL)
7318     {
7319       tree inner_if = then_block;
7320
7321       /* We know from the grammar productions that there is an IF nested
7322          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7323          it might not be exactly THEN_BLOCK, but should be the last
7324          non-container statement within.  */
7325       while (1)
7326         switch (TREE_CODE (inner_if))
7327           {
7328           case COND_EXPR:
7329             goto found;
7330           case BIND_EXPR:
7331             inner_if = BIND_EXPR_BODY (inner_if);
7332             break;
7333           case STATEMENT_LIST:
7334             inner_if = expr_last (then_block);
7335             break;
7336           case TRY_FINALLY_EXPR:
7337           case TRY_CATCH_EXPR:
7338             inner_if = TREE_OPERAND (inner_if, 0);
7339             break;
7340           default:
7341             gcc_unreachable ();
7342           }
7343     found:
7344
7345       if (COND_EXPR_ELSE (inner_if))
7346          warning (OPT_Wparentheses,
7347                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7348                   &if_locus);
7349     }
7350
7351   empty_if_body_warning (then_block, else_block);
7352
7353   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7354   SET_EXPR_LOCATION (stmt, if_locus);
7355   add_stmt (stmt);
7356 }
7357
7358 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7359    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7360    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7361    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7362    the continue label.  Everything is allowed to be NULL.  */
7363
7364 void
7365 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7366                tree blab, tree clab, bool cond_is_first)
7367 {
7368   tree entry = NULL, exit = NULL, t;
7369
7370   /* If the condition is zero don't generate a loop construct.  */
7371   if (cond && integer_zerop (cond))
7372     {
7373       if (cond_is_first)
7374         {
7375           t = build_and_jump (&blab);
7376           SET_EXPR_LOCATION (t, start_locus);
7377           add_stmt (t);
7378         }
7379     }
7380   else
7381     {
7382       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7383
7384       /* If we have an exit condition, then we build an IF with gotos either
7385          out of the loop, or to the top of it.  If there's no exit condition,
7386          then we just build a jump back to the top.  */
7387       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7388
7389       if (cond && !integer_nonzerop (cond))
7390         {
7391           /* Canonicalize the loop condition to the end.  This means
7392              generating a branch to the loop condition.  Reuse the
7393              continue label, if possible.  */
7394           if (cond_is_first)
7395             {
7396               if (incr || !clab)
7397                 {
7398                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7399                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7400                 }
7401               else
7402                 t = build1 (GOTO_EXPR, void_type_node, clab);
7403               SET_EXPR_LOCATION (t, start_locus);
7404               add_stmt (t);
7405             }
7406
7407           t = build_and_jump (&blab);
7408           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7409           if (cond_is_first)
7410             SET_EXPR_LOCATION (exit, start_locus);
7411           else
7412             SET_EXPR_LOCATION (exit, input_location);
7413         }
7414
7415       add_stmt (top);
7416     }
7417
7418   if (body)
7419     add_stmt (body);
7420   if (clab)
7421     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7422   if (incr)
7423     add_stmt (incr);
7424   if (entry)
7425     add_stmt (entry);
7426   if (exit)
7427     add_stmt (exit);
7428   if (blab)
7429     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7430 }
7431
7432 tree
7433 c_finish_bc_stmt (tree *label_p, bool is_break)
7434 {
7435   bool skip;
7436   tree label = *label_p;
7437
7438   /* In switch statements break is sometimes stylistically used after
7439      a return statement.  This can lead to spurious warnings about
7440      control reaching the end of a non-void function when it is
7441      inlined.  Note that we are calling block_may_fallthru with
7442      language specific tree nodes; this works because
7443      block_may_fallthru returns true when given something it does not
7444      understand.  */
7445   skip = !block_may_fallthru (cur_stmt_list);
7446
7447   if (!label)
7448     {
7449       if (!skip)
7450         *label_p = label = create_artificial_label ();
7451     }
7452   else if (TREE_CODE (label) == LABEL_DECL)
7453     ;
7454   else switch (TREE_INT_CST_LOW (label))
7455     {
7456     case 0:
7457       if (is_break)
7458         error ("break statement not within loop or switch");
7459       else
7460         error ("continue statement not within a loop");
7461       return NULL_TREE;
7462
7463     case 1:
7464       gcc_assert (is_break);
7465       error ("break statement used with OpenMP for loop");
7466       return NULL_TREE;
7467
7468     default:
7469       gcc_unreachable ();
7470     }
7471
7472   if (skip)
7473     return NULL_TREE;
7474
7475   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7476 }
7477
7478 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7479
7480 static void
7481 emit_side_effect_warnings (tree expr)
7482 {
7483   if (expr == error_mark_node)
7484     ;
7485   else if (!TREE_SIDE_EFFECTS (expr))
7486     {
7487       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7488         warning (OPT_Wunused_value, "%Hstatement with no effect",
7489                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7490     }
7491   else
7492     warn_if_unused_value (expr, input_location);
7493 }
7494
7495 /* Process an expression as if it were a complete statement.  Emit
7496    diagnostics, but do not call ADD_STMT.  */
7497
7498 tree
7499 c_process_expr_stmt (tree expr)
7500 {
7501   if (!expr)
7502     return NULL_TREE;
7503
7504   if (warn_sequence_point)
7505     verify_sequence_points (expr);
7506
7507   if (TREE_TYPE (expr) != error_mark_node
7508       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7509       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7510     error ("expression statement has incomplete type");
7511
7512   /* If we're not processing a statement expression, warn about unused values.
7513      Warnings for statement expressions will be emitted later, once we figure
7514      out which is the result.  */
7515   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7516       && warn_unused_value)
7517     emit_side_effect_warnings (expr);
7518
7519   /* If the expression is not of a type to which we cannot assign a line
7520      number, wrap the thing in a no-op NOP_EXPR.  */
7521   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7522     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7523
7524   if (CAN_HAVE_LOCATION_P (expr))
7525     SET_EXPR_LOCATION (expr, input_location);
7526
7527   return expr;
7528 }
7529
7530 /* Emit an expression as a statement.  */
7531
7532 tree
7533 c_finish_expr_stmt (tree expr)
7534 {
7535   if (expr)
7536     return add_stmt (c_process_expr_stmt (expr));
7537   else
7538     return NULL;
7539 }
7540
7541 /* Do the opposite and emit a statement as an expression.  To begin,
7542    create a new binding level and return it.  */
7543
7544 tree
7545 c_begin_stmt_expr (void)
7546 {
7547   tree ret;
7548   struct c_label_context_se *nstack;
7549   struct c_label_list *glist;
7550
7551   /* We must force a BLOCK for this level so that, if it is not expanded
7552      later, there is a way to turn off the entire subtree of blocks that
7553      are contained in it.  */
7554   keep_next_level ();
7555   ret = c_begin_compound_stmt (true);
7556   if (c_switch_stack)
7557     {
7558       c_switch_stack->blocked_stmt_expr++;
7559       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7560     }
7561   for (glist = label_context_stack_se->labels_used;
7562        glist != NULL;
7563        glist = glist->next)
7564     {
7565       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7566     }
7567   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7568   nstack->labels_def = NULL;
7569   nstack->labels_used = NULL;
7570   nstack->next = label_context_stack_se;
7571   label_context_stack_se = nstack;
7572
7573   /* Mark the current statement list as belonging to a statement list.  */
7574   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7575
7576   return ret;
7577 }
7578
7579 tree
7580 c_finish_stmt_expr (tree body)
7581 {
7582   tree last, type, tmp, val;
7583   tree *last_p;
7584   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7585
7586   body = c_end_compound_stmt (body, true);
7587   if (c_switch_stack)
7588     {
7589       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7590       c_switch_stack->blocked_stmt_expr--;
7591     }
7592   /* It is no longer possible to jump to labels defined within this
7593      statement expression.  */
7594   for (dlist = label_context_stack_se->labels_def;
7595        dlist != NULL;
7596        dlist = dlist->next)
7597     {
7598       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7599     }
7600   /* It is again possible to define labels with a goto just outside
7601      this statement expression.  */
7602   for (glist = label_context_stack_se->next->labels_used;
7603        glist != NULL;
7604        glist = glist->next)
7605     {
7606       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7607       glist_prev = glist;
7608     }
7609   if (glist_prev != NULL)
7610     glist_prev->next = label_context_stack_se->labels_used;
7611   else
7612     label_context_stack_se->next->labels_used
7613       = label_context_stack_se->labels_used;
7614   label_context_stack_se = label_context_stack_se->next;
7615
7616   /* Locate the last statement in BODY.  See c_end_compound_stmt
7617      about always returning a BIND_EXPR.  */
7618   last_p = &BIND_EXPR_BODY (body);
7619   last = BIND_EXPR_BODY (body);
7620
7621  continue_searching:
7622   if (TREE_CODE (last) == STATEMENT_LIST)
7623     {
7624       tree_stmt_iterator i;
7625
7626       /* This can happen with degenerate cases like ({ }).  No value.  */
7627       if (!TREE_SIDE_EFFECTS (last))
7628         return body;
7629
7630       /* If we're supposed to generate side effects warnings, process
7631          all of the statements except the last.  */
7632       if (warn_unused_value)
7633         {
7634           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7635             emit_side_effect_warnings (tsi_stmt (i));
7636         }
7637       else
7638         i = tsi_last (last);
7639       last_p = tsi_stmt_ptr (i);
7640       last = *last_p;
7641     }
7642
7643   /* If the end of the list is exception related, then the list was split
7644      by a call to push_cleanup.  Continue searching.  */
7645   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7646       || TREE_CODE (last) == TRY_CATCH_EXPR)
7647     {
7648       last_p = &TREE_OPERAND (last, 0);
7649       last = *last_p;
7650       goto continue_searching;
7651     }
7652
7653   /* In the case that the BIND_EXPR is not necessary, return the
7654      expression out from inside it.  */
7655   if (last == error_mark_node
7656       || (last == BIND_EXPR_BODY (body)
7657           && BIND_EXPR_VARS (body) == NULL))
7658     {
7659       /* Do not warn if the return value of a statement expression is
7660          unused.  */
7661       if (CAN_HAVE_LOCATION_P (last))
7662         TREE_NO_WARNING (last) = 1;
7663       return last;
7664     }
7665
7666   /* Extract the type of said expression.  */
7667   type = TREE_TYPE (last);
7668
7669   /* If we're not returning a value at all, then the BIND_EXPR that
7670      we already have is a fine expression to return.  */
7671   if (!type || VOID_TYPE_P (type))
7672     return body;
7673
7674   /* Now that we've located the expression containing the value, it seems
7675      silly to make voidify_wrapper_expr repeat the process.  Create a
7676      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7677   tmp = create_tmp_var_raw (type, NULL);
7678
7679   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7680      tree_expr_nonnegative_p giving up immediately.  */
7681   val = last;
7682   if (TREE_CODE (val) == NOP_EXPR
7683       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7684     val = TREE_OPERAND (val, 0);
7685
7686   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7687   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7688
7689   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7690 }
7691
7692 /* Begin the scope of an identifier of variably modified type, scope
7693    number SCOPE.  Jumping from outside this scope to inside it is not
7694    permitted.  */
7695
7696 void
7697 c_begin_vm_scope (unsigned int scope)
7698 {
7699   struct c_label_context_vm *nstack;
7700   struct c_label_list *glist;
7701
7702   gcc_assert (scope > 0);
7703
7704   /* At file_scope, we don't have to do any processing.  */
7705   if (label_context_stack_vm == NULL)
7706     return;
7707
7708   if (c_switch_stack && !c_switch_stack->blocked_vm)
7709     c_switch_stack->blocked_vm = scope;
7710   for (glist = label_context_stack_vm->labels_used;
7711        glist != NULL;
7712        glist = glist->next)
7713     {
7714       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7715     }
7716   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7717   nstack->labels_def = NULL;
7718   nstack->labels_used = NULL;
7719   nstack->scope = scope;
7720   nstack->next = label_context_stack_vm;
7721   label_context_stack_vm = nstack;
7722 }
7723
7724 /* End a scope which may contain identifiers of variably modified
7725    type, scope number SCOPE.  */
7726
7727 void
7728 c_end_vm_scope (unsigned int scope)
7729 {
7730   if (label_context_stack_vm == NULL)
7731     return;
7732   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7733     c_switch_stack->blocked_vm = 0;
7734   /* We may have a number of nested scopes of identifiers with
7735      variably modified type, all at this depth.  Pop each in turn.  */
7736   while (label_context_stack_vm->scope == scope)
7737     {
7738       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7739
7740       /* It is no longer possible to jump to labels defined within this
7741          scope.  */
7742       for (dlist = label_context_stack_vm->labels_def;
7743            dlist != NULL;
7744            dlist = dlist->next)
7745         {
7746           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7747         }
7748       /* It is again possible to define labels with a goto just outside
7749          this scope.  */
7750       for (glist = label_context_stack_vm->next->labels_used;
7751            glist != NULL;
7752            glist = glist->next)
7753         {
7754           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7755           glist_prev = glist;
7756         }
7757       if (glist_prev != NULL)
7758         glist_prev->next = label_context_stack_vm->labels_used;
7759       else
7760         label_context_stack_vm->next->labels_used
7761           = label_context_stack_vm->labels_used;
7762       label_context_stack_vm = label_context_stack_vm->next;
7763     }
7764 }
7765 \f
7766 /* Begin and end compound statements.  This is as simple as pushing
7767    and popping new statement lists from the tree.  */
7768
7769 tree
7770 c_begin_compound_stmt (bool do_scope)
7771 {
7772   tree stmt = push_stmt_list ();
7773   if (do_scope)
7774     push_scope ();
7775   return stmt;
7776 }
7777
7778 tree
7779 c_end_compound_stmt (tree stmt, bool do_scope)
7780 {
7781   tree block = NULL;
7782
7783   if (do_scope)
7784     {
7785       if (c_dialect_objc ())
7786         objc_clear_super_receiver ();
7787       block = pop_scope ();
7788     }
7789
7790   stmt = pop_stmt_list (stmt);
7791   stmt = c_build_bind_expr (block, stmt);
7792
7793   /* If this compound statement is nested immediately inside a statement
7794      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7795      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7796      STATEMENT_LISTs merge, and thus we can lose track of what statement
7797      was really last.  */
7798   if (cur_stmt_list
7799       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7800       && TREE_CODE (stmt) != BIND_EXPR)
7801     {
7802       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7803       TREE_SIDE_EFFECTS (stmt) = 1;
7804     }
7805
7806   return stmt;
7807 }
7808
7809 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7810    when the current scope is exited.  EH_ONLY is true when this is not
7811    meant to apply to normal control flow transfer.  */
7812
7813 void
7814 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7815 {
7816   enum tree_code code;
7817   tree stmt, list;
7818   bool stmt_expr;
7819
7820   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7821   stmt = build_stmt (code, NULL, cleanup);
7822   add_stmt (stmt);
7823   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7824   list = push_stmt_list ();
7825   TREE_OPERAND (stmt, 0) = list;
7826   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7827 }
7828 \f
7829 /* Build a binary-operation expression without default conversions.
7830    CODE is the kind of expression to build.
7831    This function differs from `build' in several ways:
7832    the data type of the result is computed and recorded in it,
7833    warnings are generated if arg data types are invalid,
7834    special handling for addition and subtraction of pointers is known,
7835    and some optimization is done (operations on narrow ints
7836    are done in the narrower type when that gives the same result).
7837    Constant folding is also done before the result is returned.
7838
7839    Note that the operands will never have enumeral types, or function
7840    or array types, because either they will have the default conversions
7841    performed or they have both just been converted to some other type in which
7842    the arithmetic is to be done.  */
7843
7844 tree
7845 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7846                  int convert_p)
7847 {
7848   tree type0, type1;
7849   enum tree_code code0, code1;
7850   tree op0, op1;
7851   const char *invalid_op_diag;
7852
7853   /* Expression code to give to the expression when it is built.
7854      Normally this is CODE, which is what the caller asked for,
7855      but in some special cases we change it.  */
7856   enum tree_code resultcode = code;
7857
7858   /* Data type in which the computation is to be performed.
7859      In the simplest cases this is the common type of the arguments.  */
7860   tree result_type = NULL;
7861
7862   /* Nonzero means operands have already been type-converted
7863      in whatever way is necessary.
7864      Zero means they need to be converted to RESULT_TYPE.  */
7865   int converted = 0;
7866
7867   /* Nonzero means create the expression with this type, rather than
7868      RESULT_TYPE.  */
7869   tree build_type = 0;
7870
7871   /* Nonzero means after finally constructing the expression
7872      convert it to this type.  */
7873   tree final_type = 0;
7874
7875   /* Nonzero if this is an operation like MIN or MAX which can
7876      safely be computed in short if both args are promoted shorts.
7877      Also implies COMMON.
7878      -1 indicates a bitwise operation; this makes a difference
7879      in the exact conditions for when it is safe to do the operation
7880      in a narrower mode.  */
7881   int shorten = 0;
7882
7883   /* Nonzero if this is a comparison operation;
7884      if both args are promoted shorts, compare the original shorts.
7885      Also implies COMMON.  */
7886   int short_compare = 0;
7887
7888   /* Nonzero if this is a right-shift operation, which can be computed on the
7889      original short and then promoted if the operand is a promoted short.  */
7890   int short_shift = 0;
7891
7892   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7893   int common = 0;
7894
7895   /* True means types are compatible as far as ObjC is concerned.  */
7896   bool objc_ok;
7897
7898   if (convert_p)
7899     {
7900       op0 = default_conversion (orig_op0);
7901       op1 = default_conversion (orig_op1);
7902     }
7903   else
7904     {
7905       op0 = orig_op0;
7906       op1 = orig_op1;
7907     }
7908
7909   type0 = TREE_TYPE (op0);
7910   type1 = TREE_TYPE (op1);
7911
7912   /* The expression codes of the data types of the arguments tell us
7913      whether the arguments are integers, floating, pointers, etc.  */
7914   code0 = TREE_CODE (type0);
7915   code1 = TREE_CODE (type1);
7916
7917   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7918   STRIP_TYPE_NOPS (op0);
7919   STRIP_TYPE_NOPS (op1);
7920
7921   /* If an error was already reported for one of the arguments,
7922      avoid reporting another error.  */
7923
7924   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7925     return error_mark_node;
7926
7927   if ((invalid_op_diag
7928        = targetm.invalid_binary_op (code, type0, type1)))
7929     {
7930       error (invalid_op_diag);
7931       return error_mark_node;
7932     }
7933
7934   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7935
7936   switch (code)
7937     {
7938     case PLUS_EXPR:
7939       /* Handle the pointer + int case.  */
7940       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7941         return pointer_int_sum (PLUS_EXPR, op0, op1);
7942       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7943         return pointer_int_sum (PLUS_EXPR, op1, op0);
7944       else
7945         common = 1;
7946       break;
7947
7948     case MINUS_EXPR:
7949       /* Subtraction of two similar pointers.
7950          We must subtract them as integers, then divide by object size.  */
7951       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7952           && comp_target_types (type0, type1))
7953         return pointer_diff (op0, op1);
7954       /* Handle pointer minus int.  Just like pointer plus int.  */
7955       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7956         return pointer_int_sum (MINUS_EXPR, op0, op1);
7957       else
7958         common = 1;
7959       break;
7960
7961     case MULT_EXPR:
7962       common = 1;
7963       break;
7964
7965     case TRUNC_DIV_EXPR:
7966     case CEIL_DIV_EXPR:
7967     case FLOOR_DIV_EXPR:
7968     case ROUND_DIV_EXPR:
7969     case EXACT_DIV_EXPR:
7970       warn_for_div_by_zero (op1);
7971
7972       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7973            || code0 == FIXED_POINT_TYPE
7974            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7975           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7976               || code1 == FIXED_POINT_TYPE
7977               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7978         {
7979           enum tree_code tcode0 = code0, tcode1 = code1;
7980
7981           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7982             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7983           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7984             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7985
7986           if (!((tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)
7987               || (tcode0 == FIXED_POINT_TYPE && tcode1 == FIXED_POINT_TYPE)))
7988             resultcode = RDIV_EXPR;
7989           else
7990             /* Although it would be tempting to shorten always here, that
7991                loses on some targets, since the modulo instruction is
7992                undefined if the quotient can't be represented in the
7993                computation mode.  We shorten only if unsigned or if
7994                dividing by something we know != -1.  */
7995             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7996                        || (TREE_CODE (op1) == INTEGER_CST
7997                            && !integer_all_onesp (op1)));
7998           common = 1;
7999         }
8000       break;
8001
8002     case BIT_AND_EXPR:
8003     case BIT_IOR_EXPR:
8004     case BIT_XOR_EXPR:
8005       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8006         shorten = -1;
8007       /* Allow vector types which are not floating point types.   */
8008       else if (code0 == VECTOR_TYPE
8009                && code1 == VECTOR_TYPE
8010                && !VECTOR_FLOAT_TYPE_P (type0)
8011                && !VECTOR_FLOAT_TYPE_P (type1))
8012         common = 1;
8013       break;
8014
8015     case TRUNC_MOD_EXPR:
8016     case FLOOR_MOD_EXPR:
8017       warn_for_div_by_zero (op1);
8018
8019       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
8020         {
8021           /* Although it would be tempting to shorten always here, that loses
8022              on some targets, since the modulo instruction is undefined if the
8023              quotient can't be represented in the computation mode.  We shorten
8024              only if unsigned or if dividing by something we know != -1.  */
8025           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
8026                      || (TREE_CODE (op1) == INTEGER_CST
8027                          && !integer_all_onesp (op1)));
8028           common = 1;
8029         }
8030       break;
8031
8032     case TRUTH_ANDIF_EXPR:
8033     case TRUTH_ORIF_EXPR:
8034     case TRUTH_AND_EXPR:
8035     case TRUTH_OR_EXPR:
8036     case TRUTH_XOR_EXPR:
8037       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
8038            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8039            || code0 == FIXED_POINT_TYPE)
8040           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
8041               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8042               || code1 == FIXED_POINT_TYPE))
8043         {
8044           /* Result of these operations is always an int,
8045              but that does not mean the operands should be
8046              converted to ints!  */
8047           result_type = integer_type_node;
8048           op0 = c_common_truthvalue_conversion (op0);
8049           op1 = c_common_truthvalue_conversion (op1);
8050           converted = 1;
8051         }
8052       break;
8053
8054       /* Shift operations: result has same type as first operand;
8055          always convert second operand to int.
8056          Also set SHORT_SHIFT if shifting rightward.  */
8057
8058     case RSHIFT_EXPR:
8059       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8060           && code1 == INTEGER_TYPE)
8061         {
8062           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8063             {
8064               if (tree_int_cst_sgn (op1) < 0)
8065                 warning (0, "right shift count is negative");
8066               else
8067                 {
8068                   if (!integer_zerop (op1))
8069                     short_shift = 1;
8070
8071                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8072                     warning (0, "right shift count >= width of type");
8073                 }
8074             }
8075
8076           /* Use the type of the value to be shifted.  */
8077           result_type = type0;
8078           /* Convert the shift-count to an integer, regardless of size
8079              of value being shifted.  */
8080           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8081             op1 = convert (integer_type_node, op1);
8082           /* Avoid converting op1 to result_type later.  */
8083           converted = 1;
8084         }
8085       break;
8086
8087     case LSHIFT_EXPR:
8088       if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
8089           && code1 == INTEGER_TYPE)
8090         {
8091           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
8092             {
8093               if (tree_int_cst_sgn (op1) < 0)
8094                 warning (0, "left shift count is negative");
8095
8096               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
8097                 warning (0, "left shift count >= width of type");
8098             }
8099
8100           /* Use the type of the value to be shifted.  */
8101           result_type = type0;
8102           /* Convert the shift-count to an integer, regardless of size
8103              of value being shifted.  */
8104           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
8105             op1 = convert (integer_type_node, op1);
8106           /* Avoid converting op1 to result_type later.  */
8107           converted = 1;
8108         }
8109       break;
8110
8111     case EQ_EXPR:
8112     case NE_EXPR:
8113       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
8114         warning (OPT_Wfloat_equal,
8115                  "comparing floating point with == or != is unsafe");
8116       /* Result of comparison is always int,
8117          but don't convert the args to int!  */
8118       build_type = integer_type_node;
8119       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8120            || code0 == FIXED_POINT_TYPE || code0 == COMPLEX_TYPE)
8121           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8122               || code1 == FIXED_POINT_TYPE || code1 == COMPLEX_TYPE))
8123         short_compare = 1;
8124       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8125         {
8126           tree tt0 = TREE_TYPE (type0);
8127           tree tt1 = TREE_TYPE (type1);
8128           /* Anything compares with void *.  void * compares with anything.
8129              Otherwise, the targets must be compatible
8130              and both must be object or both incomplete.  */
8131           if (comp_target_types (type0, type1))
8132             result_type = common_pointer_type (type0, type1);
8133           else if (VOID_TYPE_P (tt0))
8134             {
8135               /* op0 != orig_op0 detects the case of something
8136                  whose value is 0 but which isn't a valid null ptr const.  */
8137               if (pedantic && !null_pointer_constant_p (orig_op0)
8138                   && TREE_CODE (tt1) == FUNCTION_TYPE)
8139                 pedwarn ("ISO C forbids comparison of %<void *%>"
8140                          " with function pointer");
8141             }
8142           else if (VOID_TYPE_P (tt1))
8143             {
8144               if (pedantic && !null_pointer_constant_p (orig_op1)
8145                   && TREE_CODE (tt0) == FUNCTION_TYPE)
8146                 pedwarn ("ISO C forbids comparison of %<void *%>"
8147                          " with function pointer");
8148             }
8149           else
8150             /* Avoid warning about the volatile ObjC EH puts on decls.  */
8151             if (!objc_ok)
8152               pedwarn ("comparison of distinct pointer types lacks a cast");
8153
8154           if (result_type == NULL_TREE)
8155             result_type = ptr_type_node;
8156         }
8157       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8158         {
8159           if (TREE_CODE (op0) == ADDR_EXPR
8160               && decl_with_nonnull_addr_p (TREE_OPERAND (op0, 0)))
8161             warning (OPT_Waddress, "the address of %qD will never be NULL",
8162                      TREE_OPERAND (op0, 0));
8163           result_type = type0;
8164         }
8165       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8166         {
8167           if (TREE_CODE (op1) == ADDR_EXPR
8168               && decl_with_nonnull_addr_p (TREE_OPERAND (op1, 0)))
8169             warning (OPT_Waddress, "the address of %qD will never be NULL",
8170                      TREE_OPERAND (op1, 0));
8171           result_type = type1;
8172         }
8173       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8174         {
8175           result_type = type0;
8176           pedwarn ("comparison between pointer and integer");
8177         }
8178       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8179         {
8180           result_type = type1;
8181           pedwarn ("comparison between pointer and integer");
8182         }
8183       break;
8184
8185     case LE_EXPR:
8186     case GE_EXPR:
8187     case LT_EXPR:
8188     case GT_EXPR:
8189       build_type = integer_type_node;
8190       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
8191            || code0 == FIXED_POINT_TYPE)
8192           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
8193               || code1 == FIXED_POINT_TYPE))
8194         short_compare = 1;
8195       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
8196         {
8197           if (comp_target_types (type0, type1))
8198             {
8199               result_type = common_pointer_type (type0, type1);
8200               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
8201                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
8202                 pedwarn ("comparison of complete and incomplete pointers");
8203               else if (pedantic
8204                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
8205                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
8206             }
8207           else
8208             {
8209               result_type = ptr_type_node;
8210               pedwarn ("comparison of distinct pointer types lacks a cast");
8211             }
8212         }
8213       else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
8214         {
8215           result_type = type0;
8216           if (pedantic || extra_warnings)
8217             pedwarn ("ordered comparison of pointer with integer zero");
8218         }
8219       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
8220         {
8221           result_type = type1;
8222           if (pedantic)
8223             pedwarn ("ordered comparison of pointer with integer zero");
8224         }
8225       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
8226         {
8227           result_type = type0;
8228           pedwarn ("comparison between pointer and integer");
8229         }
8230       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
8231         {
8232           result_type = type1;
8233           pedwarn ("comparison between pointer and integer");
8234         }
8235       break;
8236
8237     default:
8238       gcc_unreachable ();
8239     }
8240
8241   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8242     return error_mark_node;
8243
8244   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8245       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8246           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8247                                                     TREE_TYPE (type1))))
8248     {
8249       binary_op_error (code, type0, type1);
8250       return error_mark_node;
8251     }
8252
8253   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8254        || code0 == FIXED_POINT_TYPE || code0 == VECTOR_TYPE)
8255       &&
8256       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8257        || code1 == FIXED_POINT_TYPE || code1 == VECTOR_TYPE))
8258     {
8259       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8260
8261       if (shorten || common || short_compare)
8262         {
8263           result_type = c_common_type (type0, type1);
8264           if (result_type == error_mark_node)
8265             return error_mark_node;
8266         }
8267
8268       /* For certain operations (which identify themselves by shorten != 0)
8269          if both args were extended from the same smaller type,
8270          do the arithmetic in that type and then extend.
8271
8272          shorten !=0 and !=1 indicates a bitwise operation.
8273          For them, this optimization is safe only if
8274          both args are zero-extended or both are sign-extended.
8275          Otherwise, we might change the result.
8276          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8277          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8278
8279       if (shorten && none_complex)
8280         {
8281           int unsigned0, unsigned1;
8282           tree arg0, arg1;
8283           int uns;
8284           tree type;
8285
8286           /* Cast OP0 and OP1 to RESULT_TYPE.  Doing so prevents
8287              excessive narrowing when we call get_narrower below.  For
8288              example, suppose that OP0 is of unsigned int extended
8289              from signed char and that RESULT_TYPE is long long int.
8290              If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8291              like
8292
8293                (long long int) (unsigned int) signed_char
8294
8295              which get_narrower would narrow down to
8296
8297                (unsigned int) signed char
8298
8299              If we do not cast OP0 first, get_narrower would return
8300              signed_char, which is inconsistent with the case of the
8301              explicit cast.  */
8302           op0 = convert (result_type, op0);
8303           op1 = convert (result_type, op1);
8304
8305           arg0 = get_narrower (op0, &unsigned0);
8306           arg1 = get_narrower (op1, &unsigned1);
8307
8308           /* UNS is 1 if the operation to be done is an unsigned one.  */
8309           uns = TYPE_UNSIGNED (result_type);
8310
8311           final_type = result_type;
8312
8313           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8314              but it *requires* conversion to FINAL_TYPE.  */
8315
8316           if ((TYPE_PRECISION (TREE_TYPE (op0))
8317                == TYPE_PRECISION (TREE_TYPE (arg0)))
8318               && TREE_TYPE (op0) != final_type)
8319             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8320           if ((TYPE_PRECISION (TREE_TYPE (op1))
8321                == TYPE_PRECISION (TREE_TYPE (arg1)))
8322               && TREE_TYPE (op1) != final_type)
8323             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8324
8325           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8326
8327           /* For bitwise operations, signedness of nominal type
8328              does not matter.  Consider only how operands were extended.  */
8329           if (shorten == -1)
8330             uns = unsigned0;
8331
8332           /* Note that in all three cases below we refrain from optimizing
8333              an unsigned operation on sign-extended args.
8334              That would not be valid.  */
8335
8336           /* Both args variable: if both extended in same way
8337              from same width, do it in that width.
8338              Do it unsigned if args were zero-extended.  */
8339           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8340                < TYPE_PRECISION (result_type))
8341               && (TYPE_PRECISION (TREE_TYPE (arg1))
8342                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8343               && unsigned0 == unsigned1
8344               && (unsigned0 || !uns))
8345             result_type
8346               = c_common_signed_or_unsigned_type
8347               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8348           else if (TREE_CODE (arg0) == INTEGER_CST
8349                    && (unsigned1 || !uns)
8350                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8351                        < TYPE_PRECISION (result_type))
8352                    && (type
8353                        = c_common_signed_or_unsigned_type (unsigned1,
8354                                                            TREE_TYPE (arg1)))
8355                    && !POINTER_TYPE_P (type)
8356                    && int_fits_type_p (arg0, type))
8357             result_type = type;
8358           else if (TREE_CODE (arg1) == INTEGER_CST
8359                    && (unsigned0 || !uns)
8360                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8361                        < TYPE_PRECISION (result_type))
8362                    && (type
8363                        = c_common_signed_or_unsigned_type (unsigned0,
8364                                                            TREE_TYPE (arg0)))
8365                    && !POINTER_TYPE_P (type)
8366                    && int_fits_type_p (arg1, type))
8367             result_type = type;
8368         }
8369
8370       /* Shifts can be shortened if shifting right.  */
8371
8372       if (short_shift)
8373         {
8374           int unsigned_arg;
8375           tree arg0 = get_narrower (op0, &unsigned_arg);
8376
8377           final_type = result_type;
8378
8379           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8380             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8381
8382           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8383               /* We can shorten only if the shift count is less than the
8384                  number of bits in the smaller type size.  */
8385               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8386               /* We cannot drop an unsigned shift after sign-extension.  */
8387               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8388             {
8389               /* Do an unsigned shift if the operand was zero-extended.  */
8390               result_type
8391                 = c_common_signed_or_unsigned_type (unsigned_arg,
8392                                                     TREE_TYPE (arg0));
8393               /* Convert value-to-be-shifted to that type.  */
8394               if (TREE_TYPE (op0) != result_type)
8395                 op0 = convert (result_type, op0);
8396               converted = 1;
8397             }
8398         }
8399
8400       /* Comparison operations are shortened too but differently.
8401          They identify themselves by setting short_compare = 1.  */
8402
8403       if (short_compare)
8404         {
8405           /* Don't write &op0, etc., because that would prevent op0
8406              from being kept in a register.
8407              Instead, make copies of the our local variables and
8408              pass the copies by reference, then copy them back afterward.  */
8409           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8410           enum tree_code xresultcode = resultcode;
8411           tree val
8412             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8413
8414           if (val != 0)
8415             return val;
8416
8417           op0 = xop0, op1 = xop1;
8418           converted = 1;
8419           resultcode = xresultcode;
8420
8421           if (warn_sign_compare && skip_evaluation == 0)
8422             {
8423               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8424               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8425               int unsignedp0, unsignedp1;
8426               tree primop0 = get_narrower (op0, &unsignedp0);
8427               tree primop1 = get_narrower (op1, &unsignedp1);
8428
8429               xop0 = orig_op0;
8430               xop1 = orig_op1;
8431               STRIP_TYPE_NOPS (xop0);
8432               STRIP_TYPE_NOPS (xop1);
8433
8434               /* Give warnings for comparisons between signed and unsigned
8435                  quantities that may fail.
8436
8437                  Do the checking based on the original operand trees, so that
8438                  casts will be considered, but default promotions won't be.
8439
8440                  Do not warn if the comparison is being done in a signed type,
8441                  since the signed type will only be chosen if it can represent
8442                  all the values of the unsigned type.  */
8443               if (!TYPE_UNSIGNED (result_type))
8444                 /* OK */;
8445               /* Do not warn if both operands are the same signedness.  */
8446               else if (op0_signed == op1_signed)
8447                 /* OK */;
8448               else
8449                 {
8450                   tree sop, uop;
8451                   bool ovf;
8452
8453                   if (op0_signed)
8454                     sop = xop0, uop = xop1;
8455                   else
8456                     sop = xop1, uop = xop0;
8457
8458                   /* Do not warn if the signed quantity is an
8459                      unsuffixed integer literal (or some static
8460                      constant expression involving such literals or a
8461                      conditional expression involving such literals)
8462                      and it is non-negative.  */
8463                   if (tree_expr_nonnegative_warnv_p (sop, &ovf))
8464                     /* OK */;
8465                   /* Do not warn if the comparison is an equality operation,
8466                      the unsigned quantity is an integral constant, and it
8467                      would fit in the result if the result were signed.  */
8468                   else if (TREE_CODE (uop) == INTEGER_CST
8469                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8470                            && int_fits_type_p
8471                            (uop, c_common_signed_type (result_type)))
8472                     /* OK */;
8473                   /* Do not warn if the unsigned quantity is an enumeration
8474                      constant and its maximum value would fit in the result
8475                      if the result were signed.  */
8476                   else if (TREE_CODE (uop) == INTEGER_CST
8477                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8478                            && int_fits_type_p
8479                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8480                             c_common_signed_type (result_type)))
8481                     /* OK */;
8482                   else
8483                     warning (0, "comparison between signed and unsigned");
8484                 }
8485
8486               /* Warn if two unsigned values are being compared in a size
8487                  larger than their original size, and one (and only one) is the
8488                  result of a `~' operator.  This comparison will always fail.
8489
8490                  Also warn if one operand is a constant, and the constant
8491                  does not have all bits set that are set in the ~ operand
8492                  when it is extended.  */
8493
8494               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8495                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8496                 {
8497                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8498                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8499                                             &unsignedp0);
8500                   else
8501                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8502                                             &unsignedp1);
8503
8504                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8505                     {
8506                       tree primop;
8507                       HOST_WIDE_INT constant, mask;
8508                       int unsignedp, bits;
8509
8510                       if (host_integerp (primop0, 0))
8511                         {
8512                           primop = primop1;
8513                           unsignedp = unsignedp1;
8514                           constant = tree_low_cst (primop0, 0);
8515                         }
8516                       else
8517                         {
8518                           primop = primop0;
8519                           unsignedp = unsignedp0;
8520                           constant = tree_low_cst (primop1, 0);
8521                         }
8522
8523                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8524                       if (bits < TYPE_PRECISION (result_type)
8525                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8526                         {
8527                           mask = (~(HOST_WIDE_INT) 0) << bits;
8528                           if ((mask & constant) != mask)
8529                             warning (0, "comparison of promoted ~unsigned with constant");
8530                         }
8531                     }
8532                   else if (unsignedp0 && unsignedp1
8533                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8534                                < TYPE_PRECISION (result_type))
8535                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8536                                < TYPE_PRECISION (result_type)))
8537                     warning (0, "comparison of promoted ~unsigned with unsigned");
8538                 }
8539             }
8540         }
8541     }
8542
8543   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8544      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8545      Then the expression will be built.
8546      It will be given type FINAL_TYPE if that is nonzero;
8547      otherwise, it will be given type RESULT_TYPE.  */
8548
8549   if (!result_type)
8550     {
8551       binary_op_error (code, TREE_TYPE (op0), TREE_TYPE (op1));
8552       return error_mark_node;
8553     }
8554
8555   if (!converted)
8556     {
8557       if (TREE_TYPE (op0) != result_type)
8558         op0 = convert_and_check (result_type, op0);
8559       if (TREE_TYPE (op1) != result_type)
8560         op1 = convert_and_check (result_type, op1);
8561
8562       /* This can happen if one operand has a vector type, and the other
8563          has a different type.  */
8564       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8565         return error_mark_node;
8566     }
8567
8568   if (build_type == NULL_TREE)
8569     build_type = result_type;
8570
8571   {
8572     /* Treat expressions in initializers specially as they can't trap.  */
8573     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8574                                                                     build_type,
8575                                                                     op0, op1)
8576                                          : fold_build2 (resultcode, build_type,
8577                                                         op0, op1);
8578
8579     if (final_type != 0)
8580       result = convert (final_type, result);
8581     return result;
8582   }
8583 }
8584
8585
8586 /* Convert EXPR to be a truth-value, validating its type for this
8587    purpose.  */
8588
8589 tree
8590 c_objc_common_truthvalue_conversion (tree expr)
8591 {
8592   switch (TREE_CODE (TREE_TYPE (expr)))
8593     {
8594     case ARRAY_TYPE:
8595       error ("used array that cannot be converted to pointer where scalar is required");
8596       return error_mark_node;
8597
8598     case RECORD_TYPE:
8599       error ("used struct type value where scalar is required");
8600       return error_mark_node;
8601
8602     case UNION_TYPE:
8603       error ("used union type value where scalar is required");
8604       return error_mark_node;
8605
8606     case FUNCTION_TYPE:
8607       gcc_unreachable ();
8608
8609     default:
8610       break;
8611     }
8612
8613   /* ??? Should we also give an error for void and vectors rather than
8614      leaving those to give errors later?  */
8615   return c_common_truthvalue_conversion (expr);
8616 }
8617 \f
8618
8619 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8620    required.  */
8621
8622 tree
8623 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8624                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8625 {
8626   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8627     {
8628       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8629       /* Executing a compound literal inside a function reinitializes
8630          it.  */
8631       if (!TREE_STATIC (decl))
8632         *se = true;
8633       return decl;
8634     }
8635   else
8636     return expr;
8637 }
8638 \f
8639 /* Like c_begin_compound_stmt, except force the retention of the BLOCK.  */
8640
8641 tree
8642 c_begin_omp_parallel (void)
8643 {
8644   tree block;
8645
8646   keep_next_level ();
8647   block = c_begin_compound_stmt (true);
8648
8649   return block;
8650 }
8651
8652 tree
8653 c_finish_omp_parallel (tree clauses, tree block)
8654 {
8655   tree stmt;
8656
8657   block = c_end_compound_stmt (block, true);
8658
8659   stmt = make_node (OMP_PARALLEL);
8660   TREE_TYPE (stmt) = void_type_node;
8661   OMP_PARALLEL_CLAUSES (stmt) = clauses;
8662   OMP_PARALLEL_BODY (stmt) = block;
8663
8664   return add_stmt (stmt);
8665 }
8666
8667 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8668    Remove any elements from the list that are invalid.  */
8669
8670 tree
8671 c_finish_omp_clauses (tree clauses)
8672 {
8673   bitmap_head generic_head, firstprivate_head, lastprivate_head;
8674   tree c, t, *pc = &clauses;
8675   const char *name;
8676
8677   bitmap_obstack_initialize (NULL);
8678   bitmap_initialize (&generic_head, &bitmap_default_obstack);
8679   bitmap_initialize (&firstprivate_head, &bitmap_default_obstack);
8680   bitmap_initialize (&lastprivate_head, &bitmap_default_obstack);
8681
8682   for (pc = &clauses, c = clauses; c ; c = *pc)
8683     {
8684       bool remove = false;
8685       bool need_complete = false;
8686       bool need_implicitly_determined = false;
8687
8688       switch (OMP_CLAUSE_CODE (c))
8689         {
8690         case OMP_CLAUSE_SHARED:
8691           name = "shared";
8692           need_implicitly_determined = true;
8693           goto check_dup_generic;
8694
8695         case OMP_CLAUSE_PRIVATE:
8696           name = "private";
8697           need_complete = true;
8698           need_implicitly_determined = true;
8699           goto check_dup_generic;
8700
8701         case OMP_CLAUSE_REDUCTION:
8702           name = "reduction";
8703           need_implicitly_determined = true;
8704           t = OMP_CLAUSE_DECL (c);
8705           if (AGGREGATE_TYPE_P (TREE_TYPE (t))
8706               || POINTER_TYPE_P (TREE_TYPE (t)))
8707             {
8708               error ("%qE has invalid type for %<reduction%>", t);
8709               remove = true;
8710             }
8711           else if (FLOAT_TYPE_P (TREE_TYPE (t)))
8712             {
8713               enum tree_code r_code = OMP_CLAUSE_REDUCTION_CODE (c);
8714               const char *r_name = NULL;
8715
8716               switch (r_code)
8717                 {
8718                 case PLUS_EXPR:
8719                 case MULT_EXPR:
8720                 case MINUS_EXPR:
8721                   break;
8722                 case BIT_AND_EXPR:
8723                   r_name = "&";
8724                   break;
8725                 case BIT_XOR_EXPR:
8726                   r_name = "^";
8727                   break;
8728                 case BIT_IOR_EXPR:
8729                   r_name = "|";
8730                   break;
8731                 case TRUTH_ANDIF_EXPR:
8732                   r_name = "&&";
8733                   break;
8734                 case TRUTH_ORIF_EXPR:
8735                   r_name = "||";
8736                   break;
8737                 default:
8738                   gcc_unreachable ();
8739                 }
8740               if (r_name)
8741                 {
8742                   error ("%qE has invalid type for %<reduction(%s)%>",
8743                          t, r_name);
8744                   remove = true;
8745                 }
8746             }
8747           goto check_dup_generic;
8748
8749         case OMP_CLAUSE_COPYPRIVATE:
8750           name = "copyprivate";
8751           goto check_dup_generic;
8752
8753         case OMP_CLAUSE_COPYIN:
8754           name = "copyin";
8755           t = OMP_CLAUSE_DECL (c);
8756           if (TREE_CODE (t) != VAR_DECL || !DECL_THREAD_LOCAL_P (t))
8757             {
8758               error ("%qE must be %<threadprivate%> for %<copyin%>", t);
8759               remove = true;
8760             }
8761           goto check_dup_generic;
8762
8763         check_dup_generic:
8764           t = OMP_CLAUSE_DECL (c);
8765           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8766             {
8767               error ("%qE is not a variable in clause %qs", t, name);
8768               remove = true;
8769             }
8770           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8771                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t))
8772                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8773             {
8774               error ("%qE appears more than once in data clauses", t);
8775               remove = true;
8776             }
8777           else
8778             bitmap_set_bit (&generic_head, DECL_UID (t));
8779           break;
8780
8781         case OMP_CLAUSE_FIRSTPRIVATE:
8782           name = "firstprivate";
8783           t = OMP_CLAUSE_DECL (c);
8784           need_complete = true;
8785           need_implicitly_determined = true;
8786           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8787             {
8788               error ("%qE is not a variable in clause %<firstprivate%>", t);
8789               remove = true;
8790             }
8791           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8792                    || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
8793             {
8794               error ("%qE appears more than once in data clauses", t);
8795               remove = true;
8796             }
8797           else
8798             bitmap_set_bit (&firstprivate_head, DECL_UID (t));
8799           break;
8800
8801         case OMP_CLAUSE_LASTPRIVATE:
8802           name = "lastprivate";
8803           t = OMP_CLAUSE_DECL (c);
8804           need_complete = true;
8805           need_implicitly_determined = true;
8806           if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
8807             {
8808               error ("%qE is not a variable in clause %<lastprivate%>", t);
8809               remove = true;
8810             }
8811           else if (bitmap_bit_p (&generic_head, DECL_UID (t))
8812                    || bitmap_bit_p (&lastprivate_head, DECL_UID (t)))
8813             {
8814               error ("%qE appears more than once in data clauses", t);
8815               remove = true;
8816             }
8817           else
8818             bitmap_set_bit (&lastprivate_head, DECL_UID (t));
8819           break;
8820
8821         case OMP_CLAUSE_IF:
8822         case OMP_CLAUSE_NUM_THREADS:
8823         case OMP_CLAUSE_SCHEDULE:
8824         case OMP_CLAUSE_NOWAIT:
8825         case OMP_CLAUSE_ORDERED:
8826         case OMP_CLAUSE_DEFAULT:
8827           pc = &OMP_CLAUSE_CHAIN (c);
8828           continue;
8829
8830         default:
8831           gcc_unreachable ();
8832         }
8833
8834       if (!remove)
8835         {
8836           t = OMP_CLAUSE_DECL (c);
8837
8838           if (need_complete)
8839             {
8840               t = require_complete_type (t);
8841               if (t == error_mark_node)
8842                 remove = true;
8843             }
8844
8845           if (need_implicitly_determined)
8846             {
8847               const char *share_name = NULL;
8848
8849               if (TREE_CODE (t) == VAR_DECL && DECL_THREAD_LOCAL_P (t))
8850                 share_name = "threadprivate";
8851               else switch (c_omp_predetermined_sharing (t))
8852                 {
8853                 case OMP_CLAUSE_DEFAULT_UNSPECIFIED:
8854                   break;
8855                 case OMP_CLAUSE_DEFAULT_SHARED:
8856                   share_name = "shared";
8857                   break;
8858                 case OMP_CLAUSE_DEFAULT_PRIVATE:
8859                   share_name = "private";
8860                   break;
8861                 default:
8862                   gcc_unreachable ();
8863                 }
8864               if (share_name)
8865                 {
8866                   error ("%qE is predetermined %qs for %qs",
8867                          t, share_name, name);
8868                   remove = true;
8869                 }
8870             }
8871         }
8872
8873       if (remove)
8874         *pc = OMP_CLAUSE_CHAIN (c);
8875       else
8876         pc = &OMP_CLAUSE_CHAIN (c);
8877     }
8878
8879   bitmap_obstack_release (NULL);
8880   return clauses;
8881 }