contrib/gcc-4.1/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 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  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 tree qualify_type (tree, tree);
  78 static int tagged_types_tu_compatible_p (tree, tree);
  79 static int comp_target_types (tree, tree);
  80 static int function_types_compatible_p (tree, tree);
  81 static int type_lists_compatible_p (tree, tree);
  82 static tree decl_constant_value_for_broken_optimization (tree);
  83 static tree lookup_field (tree, tree);
  84 static tree convert_arguments (tree, tree, tree, tree);
  85 static tree pointer_diff (tree, tree);
  86 static tree convert_for_assignment (tree, tree, enum impl_conv, tree, tree,
  87                                     int);
  88 static tree valid_compound_expr_initializer (tree, tree);
  89 static void push_string (const char *);
  90 static void push_member_name (tree);
  91 static int spelling_length (void);
  92 static char *print_spelling (char *);
  93 static void warning_init (const char *);
  94 static tree digest_init (tree, tree, bool, int);
  95 static void output_init_element (tree, bool, tree, tree, int);
  96 static void output_pending_init_elements (int);
  97 static int set_designator (int);
  98 static void push_range_stack (tree);
  99 static void add_pending_init (tree, tree);
 100 static void set_nonincremental_init (void);
 101 static void set_nonincremental_init_from_string (tree);
 102 static tree find_init_member (tree);
 103 static void readonly_error (tree, enum lvalue_use);
 104 static int lvalue_or_else (tree, enum lvalue_use);
 105 static int lvalue_p (tree);
 106 static void record_maybe_used_decl (tree);
 107 static int comptypes_internal (tree, tree);
 108 \f/* This is a cache to hold if two types are compatible or not.  */
 109
 110 struct tagged_tu_seen_cache {
 111   const struct tagged_tu_seen_cache * next;
 112   tree t1;
 113   tree t2;
 114   /* The return value of tagged_types_tu_compatible_p if we had seen
 115      these two types already.  */
 116   int val;
 117 };
 118
 119 static const struct tagged_tu_seen_cache * tagged_tu_seen_base;
 120 static void free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *);
 121
 122 /* Do `exp = require_complete_type (exp);' to make sure exp
 123    does not have an incomplete type.  (That includes void types.)  */
 124
 125 tree
 126 require_complete_type (tree value)
 127 {
 128   tree type = TREE_TYPE (value);
 129
 130   if (value == error_mark_node || type == error_mark_node)
 131     return error_mark_node;
 132
 133   /* First, detect a valid value with a complete type.  */
 134   if (COMPLETE_TYPE_P (type))
 135     return value;
 136
 137   c_incomplete_type_error (value, type);
 138   return error_mark_node;
 139 }
 140
 141 /* Print an error message for invalid use of an incomplete type.
 142    VALUE is the expression that was used (or 0 if that isn't known)
 143    and TYPE is the type that was invalid.  */
 144
 145 void
 146 c_incomplete_type_error (tree value, tree type)
 147 {
 148   const char *type_code_string;
 149
 150   /* Avoid duplicate error message.  */
 151   if (TREE_CODE (type) == ERROR_MARK)
 152     return;
 153
 154   if (value != 0 && (TREE_CODE (value) == VAR_DECL
 155                      || TREE_CODE (value) == PARM_DECL))
 156     error ("%qD has an incomplete type", value);
 157   else
 158     {
 159     retry:
 160       /* We must print an error message.  Be clever about what it says.  */
 161
 162       switch (TREE_CODE (type))
 163         {
 164         case RECORD_TYPE:
 165           type_code_string = "struct";
 166           break;
 167
 168         case UNION_TYPE:
 169           type_code_string = "union";
 170           break;
 171
 172         case ENUMERAL_TYPE:
 173           type_code_string = "enum";
 174           break;
 175
 176         case VOID_TYPE:
 177           error ("invalid use of void expression");
 178           return;
 179
 180         case ARRAY_TYPE:
 181           if (TYPE_DOMAIN (type))
 182             {
 183               if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL)
 184                 {
 185                   error ("invalid use of flexible array member");
 186                   return;
 187                 }
 188               type = TREE_TYPE (type);
 189               goto retry;
 190             }
 191           error ("invalid use of array with unspecified bounds");
 192           return;
 193
 194         default:
 195           gcc_unreachable ();
 196         }
 197
 198       if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
 199         error ("invalid use of undefined type %<%s %E%>",
 200                type_code_string, TYPE_NAME (type));
 201       else
 202         /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
 203         error ("invalid use of incomplete typedef %qD", TYPE_NAME (type));
 204     }
 205 }
 206
 207 /* Given a type, apply default promotions wrt unnamed function
 208    arguments and return the new type.  */
 209
 210 tree
 211 c_type_promotes_to (tree type)
 212 {
 213   if (TYPE_MAIN_VARIANT (type) == float_type_node)
 214     return double_type_node;
 215
 216   if (c_promoting_integer_type_p (type))
 217     {
 218       /* Preserve unsignedness if not really getting any wider.  */
 219       if (TYPE_UNSIGNED (type)
 220           && (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
 221         return unsigned_type_node;
 222       return integer_type_node;
 223     }
 224
 225   return type;
 226 }
 227
 228 /* Return a variant of TYPE which has all the type qualifiers of LIKE
 229    as well as those of TYPE.  */
 230
 231 static tree
 232 qualify_type (tree type, tree like)
 233 {
 234   return c_build_qualified_type (type,
 235                                  TYPE_QUALS (type) | TYPE_QUALS (like));
 236 }
 237 \f
 238 /* Return the composite type of two compatible types.
 239
 240    We assume that comptypes has already been done and returned
 241    nonzero; if that isn't so, this may crash.  In particular, we
 242    assume that qualifiers match.  */
 243
 244 tree
 245 composite_type (tree t1, tree t2)
 246 {
 247   enum tree_code code1;
 248   enum tree_code code2;
 249   tree attributes;
 250
 251   /* Save time if the two types are the same.  */
 252
 253   if (t1 == t2) return t1;
 254
 255   /* If one type is nonsense, use the other.  */
 256   if (t1 == error_mark_node)
 257     return t2;
 258   if (t2 == error_mark_node)
 259     return t1;
 260
 261   code1 = TREE_CODE (t1);
 262   code2 = TREE_CODE (t2);
 263
 264   /* Merge the attributes.  */
 265   attributes = targetm.merge_type_attributes (t1, t2);
 266
 267   /* If one is an enumerated type and the other is the compatible
 268      integer type, the composite type might be either of the two
 269      (DR#013 question 3).  For consistency, use the enumerated type as
 270      the composite type.  */
 271
 272   if (code1 == ENUMERAL_TYPE && code2 == INTEGER_TYPE)
 273     return t1;
 274   if (code2 == ENUMERAL_TYPE && code1 == INTEGER_TYPE)
 275     return t2;
 276
 277   gcc_assert (code1 == code2);
 278
 279   switch (code1)
 280     {
 281     case POINTER_TYPE:
 282       /* For two pointers, do this recursively on the target type.  */
 283       {
 284         tree pointed_to_1 = TREE_TYPE (t1);
 285         tree pointed_to_2 = TREE_TYPE (t2);
 286         tree target = composite_type (pointed_to_1, pointed_to_2);
 287         t1 = build_pointer_type (target);
 288         t1 = build_type_attribute_variant (t1, attributes);
 289         return qualify_type (t1, t2);
 290       }
 291
 292     case ARRAY_TYPE:
 293       {
 294         tree elt = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 295         int quals;
 296         tree unqual_elt;
 297         tree d1 = TYPE_DOMAIN (t1);
 298         tree d2 = TYPE_DOMAIN (t2);
 299         bool d1_variable, d2_variable;
 300         bool d1_zero, d2_zero;
 301
 302         /* We should not have any type quals on arrays at all.  */
 303         gcc_assert (!TYPE_QUALS (t1) && !TYPE_QUALS (t2));
 304
 305         d1_zero = d1 == 0 || !TYPE_MAX_VALUE (d1);
 306         d2_zero = d2 == 0 || !TYPE_MAX_VALUE (d2);
 307
 308         d1_variable = (!d1_zero
 309                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 310                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 311         d2_variable = (!d2_zero
 312                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 313                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 314
 315         /* Save space: see if the result is identical to one of the args.  */
 316         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)
 317             && (d2_variable || d2_zero || !d1_variable))
 318           return build_type_attribute_variant (t1, attributes);
 319         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)
 320             && (d1_variable || d1_zero || !d2_variable))
 321           return build_type_attribute_variant (t2, attributes);
 322
 323         if (elt == TREE_TYPE (t1) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 324           return build_type_attribute_variant (t1, attributes);
 325         if (elt == TREE_TYPE (t2) && !TYPE_DOMAIN (t2) && !TYPE_DOMAIN (t1))
 326           return build_type_attribute_variant (t2, attributes);
 327
 328         /* Merge the element types, and have a size if either arg has
 329            one.  We may have qualifiers on the element types.  To set
 330            up TYPE_MAIN_VARIANT correctly, we need to form the
 331            composite of the unqualified types and add the qualifiers
 332            back at the end.  */
 333         quals = TYPE_QUALS (strip_array_types (elt));
 334         unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
 335         t1 = build_array_type (unqual_elt,
 336                                TYPE_DOMAIN ((TYPE_DOMAIN (t1)
 337                                              && (d2_variable
 338                                                  || d2_zero
 339                                                  || !d1_variable))
 340                                             ? t1
 341                                             : t2));
 342         t1 = c_build_qualified_type (t1, quals);
 343         return build_type_attribute_variant (t1, attributes);
 344       }
 345
 346     case FUNCTION_TYPE:
 347       /* Function types: prefer the one that specified arg types.
 348          If both do, merge the arg types.  Also merge the return types.  */
 349       {
 350         tree valtype = composite_type (TREE_TYPE (t1), TREE_TYPE (t2));
 351         tree p1 = TYPE_ARG_TYPES (t1);
 352         tree p2 = TYPE_ARG_TYPES (t2);
 353         int len;
 354         tree newargs, n;
 355         int i;
 356
 357         /* Save space: see if the result is identical to one of the args.  */
 358         if (valtype == TREE_TYPE (t1) && !TYPE_ARG_TYPES (t2))
 359           return build_type_attribute_variant (t1, attributes);
 360         if (valtype == TREE_TYPE (t2) && !TYPE_ARG_TYPES (t1))
 361           return build_type_attribute_variant (t2, attributes);
 362
 363         /* Simple way if one arg fails to specify argument types.  */
 364         if (TYPE_ARG_TYPES (t1) == 0)
 365          {
 366             t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
 367             t1 = build_type_attribute_variant (t1, attributes);
 368             return qualify_type (t1, t2);
 369          }
 370         if (TYPE_ARG_TYPES (t2) == 0)
 371          {
 372            t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
 373            t1 = build_type_attribute_variant (t1, attributes);
 374            return qualify_type (t1, t2);
 375          }
 376
 377         /* If both args specify argument types, we must merge the two
 378            lists, argument by argument.  */
 379         /* Tell global_bindings_p to return false so that variable_size
 380            doesn't die on VLAs in parameter types.  */
 381         c_override_global_bindings_to_false = true;
 382
 383         len = list_length (p1);
 384         newargs = 0;
 385
 386         for (i = 0; i < len; i++)
 387           newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 388
 389         n = newargs;
 390
 391         for (; p1;
 392              p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 393           {
 394             /* A null type means arg type is not specified.
 395                Take whatever the other function type has.  */
 396             if (TREE_VALUE (p1) == 0)
 397               {
 398                 TREE_VALUE (n) = TREE_VALUE (p2);
 399                 goto parm_done;
 400               }
 401             if (TREE_VALUE (p2) == 0)
 402               {
 403                 TREE_VALUE (n) = TREE_VALUE (p1);
 404                 goto parm_done;
 405               }
 406
 407             /* Given  wait (union {union wait *u; int *i} *)
 408                and  wait (union wait *),
 409                prefer  union wait *  as type of parm.  */
 410             if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
 411                 && TREE_VALUE (p1) != TREE_VALUE (p2))
 412               {
 413                 tree memb;
 414                 tree mv2 = TREE_VALUE (p2);
 415                 if (mv2 && mv2 != error_mark_node
 416                     && TREE_CODE (mv2) != ARRAY_TYPE)
 417                   mv2 = TYPE_MAIN_VARIANT (mv2);
 418                 for (memb = TYPE_FIELDS (TREE_VALUE (p1));
 419                      memb; memb = TREE_CHAIN (memb))
 420                   {
 421                     tree mv3 = TREE_TYPE (memb);
 422                     if (mv3 && mv3 != error_mark_node
 423                         && TREE_CODE (mv3) != ARRAY_TYPE)
 424                       mv3 = TYPE_MAIN_VARIANT (mv3);
 425                     if (comptypes (mv3, mv2))
 426                       {
 427                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 428                                                          TREE_VALUE (p2));
 429                         if (pedantic)
 430                           pedwarn ("function types not truly compatible in ISO C");
 431                         goto parm_done;
 432                       }
 433                   }
 434               }
 435             if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
 436                 && TREE_VALUE (p2) != TREE_VALUE (p1))
 437               {
 438                 tree memb;
 439                 tree mv1 = TREE_VALUE (p1);
 440                 if (mv1 && mv1 != error_mark_node
 441                     && TREE_CODE (mv1) != ARRAY_TYPE)
 442                   mv1 = TYPE_MAIN_VARIANT (mv1);
 443                 for (memb = TYPE_FIELDS (TREE_VALUE (p2));
 444                      memb; memb = TREE_CHAIN (memb))
 445                   {
 446                     tree mv3 = TREE_TYPE (memb);
 447                     if (mv3 && mv3 != error_mark_node
 448                         && TREE_CODE (mv3) != ARRAY_TYPE)
 449                       mv3 = TYPE_MAIN_VARIANT (mv3);
 450                     if (comptypes (mv3, mv1))
 451                       {
 452                         TREE_VALUE (n) = composite_type (TREE_TYPE (memb),
 453                                                          TREE_VALUE (p1));
 454                         if (pedantic)
 455                           pedwarn ("function types not truly compatible in ISO C");
 456                         goto parm_done;
 457                       }
 458                   }
 459               }
 460             TREE_VALUE (n) = composite_type (TREE_VALUE (p1), TREE_VALUE (p2));
 461           parm_done: ;
 462           }
 463
 464         c_override_global_bindings_to_false = false;
 465         t1 = build_function_type (valtype, newargs);
 466         t1 = qualify_type (t1, t2);
 467         /* ... falls through ...  */
 468       }
 469
 470     default:
 471       return build_type_attribute_variant (t1, attributes);
 472     }
 473
 474 }
 475
 476 /* Return the type of a conditional expression between pointers to
 477    possibly differently qualified versions of compatible types.
 478
 479    We assume that comp_target_types has already been done and returned
 480    nonzero; if that isn't so, this may crash.  */
 481
 482 static tree
 483 common_pointer_type (tree t1, tree t2)
 484 {
 485   tree attributes;
 486   tree pointed_to_1, mv1;
 487   tree pointed_to_2, mv2;
 488   tree target;
 489
 490   /* Save time if the two types are the same.  */
 491
 492   if (t1 == t2) return t1;
 493
 494   /* If one type is nonsense, use the other.  */
 495   if (t1 == error_mark_node)
 496     return t2;
 497   if (t2 == error_mark_node)
 498     return t1;
 499
 500   gcc_assert (TREE_CODE (t1) == POINTER_TYPE
 501               && TREE_CODE (t2) == POINTER_TYPE);
 502
 503   /* Merge the attributes.  */
 504   attributes = targetm.merge_type_attributes (t1, t2);
 505
 506   /* Find the composite type of the target types, and combine the
 507      qualifiers of the two types' targets.  Do not lose qualifiers on
 508      array element types by taking the TYPE_MAIN_VARIANT.  */
 509   mv1 = pointed_to_1 = TREE_TYPE (t1);
 510   mv2 = pointed_to_2 = TREE_TYPE (t2);
 511   if (TREE_CODE (mv1) != ARRAY_TYPE)
 512     mv1 = TYPE_MAIN_VARIANT (pointed_to_1);
 513   if (TREE_CODE (mv2) != ARRAY_TYPE)
 514     mv2 = TYPE_MAIN_VARIANT (pointed_to_2);
 515   target = composite_type (mv1, mv2);
 516   t1 = build_pointer_type (c_build_qualified_type
 517                            (target,
 518                             TYPE_QUALS (pointed_to_1) |
 519                             TYPE_QUALS (pointed_to_2)));
 520   return build_type_attribute_variant (t1, attributes);
 521 }
 522
 523 /* Return the common type for two arithmetic types under the usual
 524    arithmetic conversions.  The default conversions have already been
 525    applied, and enumerated types converted to their compatible integer
 526    types.  The resulting type is unqualified and has no attributes.
 527
 528    This is the type for the result of most arithmetic operations
 529    if the operands have the given two types.  */
 530
 531 static tree
 532 c_common_type (tree t1, tree t2)
 533 {
 534   enum tree_code code1;
 535   enum tree_code code2;
 536
 537   /* If one type is nonsense, use the other.  */
 538   if (t1 == error_mark_node)
 539     return t2;
 540   if (t2 == error_mark_node)
 541     return t1;
 542
 543   if (TYPE_QUALS (t1) != TYPE_UNQUALIFIED)
 544     t1 = TYPE_MAIN_VARIANT (t1);
 545
 546   if (TYPE_QUALS (t2) != TYPE_UNQUALIFIED)
 547     t2 = TYPE_MAIN_VARIANT (t2);
 548
 549   if (TYPE_ATTRIBUTES (t1) != NULL_TREE)
 550     t1 = build_type_attribute_variant (t1, NULL_TREE);
 551
 552   if (TYPE_ATTRIBUTES (t2) != NULL_TREE)
 553     t2 = build_type_attribute_variant (t2, NULL_TREE);
 554
 555   /* Save time if the two types are the same.  */
 556
 557   if (t1 == t2) return t1;
 558
 559   code1 = TREE_CODE (t1);
 560   code2 = TREE_CODE (t2);
 561
 562   gcc_assert (code1 == VECTOR_TYPE || code1 == COMPLEX_TYPE
 563               || code1 == REAL_TYPE || code1 == INTEGER_TYPE);
 564   gcc_assert (code2 == VECTOR_TYPE || code2 == COMPLEX_TYPE
 565               || code2 == REAL_TYPE || code2 == INTEGER_TYPE);
 566
 567   /* If one type is a vector type, return that type.  (How the usual
 568      arithmetic conversions apply to the vector types extension is not
 569      precisely specified.)  */
 570   if (code1 == VECTOR_TYPE)
 571     return t1;
 572
 573   if (code2 == VECTOR_TYPE)
 574     return t2;
 575
 576   /* If one type is complex, form the common type of the non-complex
 577      components, then make that complex.  Use T1 or T2 if it is the
 578      required type.  */
 579   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 580     {
 581       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 582       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 583       tree subtype = c_common_type (subtype1, subtype2);
 584
 585       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 586         return t1;
 587       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 588         return t2;
 589       else
 590         return build_complex_type (subtype);
 591     }
 592
 593   /* If only one is real, use it as the result.  */
 594
 595   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 596     return t1;
 597
 598   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 599     return t2;
 600
 601   /* Both real or both integers; use the one with greater precision.  */
 602
 603   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 604     return t1;
 605   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 606     return t2;
 607
 608   /* Same precision.  Prefer long longs to longs to ints when the
 609      same precision, following the C99 rules on integer type rank
 610      (which are equivalent to the C90 rules for C90 types).  */
 611
 612   if (TYPE_MAIN_VARIANT (t1) == long_long_unsigned_type_node
 613       || TYPE_MAIN_VARIANT (t2) == long_long_unsigned_type_node)
 614     return long_long_unsigned_type_node;
 615
 616   if (TYPE_MAIN_VARIANT (t1) == long_long_integer_type_node
 617       || TYPE_MAIN_VARIANT (t2) == long_long_integer_type_node)
 618     {
 619       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 620         return long_long_unsigned_type_node;
 621       else
 622         return long_long_integer_type_node;
 623     }
 624
 625   if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
 626       || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
 627     return long_unsigned_type_node;
 628
 629   if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
 630       || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
 631     {
 632       /* But preserve unsignedness from the other type,
 633          since long cannot hold all the values of an unsigned int.  */
 634       if (TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2))
 635         return long_unsigned_type_node;
 636       else
 637         return long_integer_type_node;
 638     }
 639
 640   /* Likewise, prefer long double to double even if same size.  */
 641   if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
 642       || TYPE_MAIN_VARIANT (t2) == long_double_type_node)
 643     return long_double_type_node;
 644
 645   /* Otherwise prefer the unsigned one.  */
 646
 647   if (TYPE_UNSIGNED (t1))
 648     return t1;
 649   else
 650     return t2;
 651 }
 652 \f
 653 /* Wrapper around c_common_type that is used by c-common.c and other
 654    front end optimizations that remove promotions.  ENUMERAL_TYPEs
 655    are allowed here and are converted to their compatible integer types.
 656    BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
 657    preferably a non-Boolean type as the common type.  */
 658 tree
 659 common_type (tree t1, tree t2)
 660 {
 661   if (TREE_CODE (t1) == ENUMERAL_TYPE)
 662     t1 = c_common_type_for_size (TYPE_PRECISION (t1), 1);
 663   if (TREE_CODE (t2) == ENUMERAL_TYPE)
 664     t2 = c_common_type_for_size (TYPE_PRECISION (t2), 1);
 665
 666   /* If both types are BOOLEAN_TYPE, then return boolean_type_node.  */
 667   if (TREE_CODE (t1) == BOOLEAN_TYPE
 668       && TREE_CODE (t2) == BOOLEAN_TYPE)
 669     return boolean_type_node;
 670
 671   /* If either type is BOOLEAN_TYPE, then return the other.  */
 672   if (TREE_CODE (t1) == BOOLEAN_TYPE)
 673     return t2;
 674   if (TREE_CODE (t2) == BOOLEAN_TYPE)
 675     return t1;
 676
 677   return c_common_type (t1, t2);
 678 }
 679
 680 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 681    or various other operations.  Return 2 if they are compatible
 682    but a warning may be needed if you use them together.  */
 683
 684 int
 685 comptypes (tree type1, tree type2)
 686 {
 687   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
 688   int val;
 689
 690   val = comptypes_internal (type1, type2);
 691   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 692
 693   return val;
 694 }\f
 695 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
 696    or various other operations.  Return 2 if they are compatible
 697    but a warning may be needed if you use them together.  This
 698    differs from comptypes, in that we don't free the seen types.  */
 699
 700 static int
 701 comptypes_internal (tree type1, tree type2)
 702 {
 703   tree t1 = type1;
 704   tree t2 = type2;
 705   int attrval, val;
 706
 707   /* Suppress errors caused by previously reported errors.  */
 708
 709   if (t1 == t2 || !t1 || !t2
 710       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
 711     return 1;
 712
 713   /* If either type is the internal version of sizetype, return the
 714      language version.  */
 715   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 716       && TYPE_ORIG_SIZE_TYPE (t1))
 717     t1 = TYPE_ORIG_SIZE_TYPE (t1);
 718
 719   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 720       && TYPE_ORIG_SIZE_TYPE (t2))
 721     t2 = TYPE_ORIG_SIZE_TYPE (t2);
 722
 723
 724   /* Enumerated types are compatible with integer types, but this is
 725      not transitive: two enumerated types in the same translation unit
 726      are compatible with each other only if they are the same type.  */
 727
 728   if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
 729     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
 730   else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
 731     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
 732
 733   if (t1 == t2)
 734     return 1;
 735
 736   /* Different classes of types can't be compatible.  */
 737
 738   if (TREE_CODE (t1) != TREE_CODE (t2))
 739     return 0;
 740
 741   /* Qualifiers must match. C99 6.7.3p9 */
 742
 743   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
 744     return 0;
 745
 746   /* Allow for two different type nodes which have essentially the same
 747      definition.  Note that we already checked for equality of the type
 748      qualifiers (just above).  */
 749
 750   if (TREE_CODE (t1) != ARRAY_TYPE
 751       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 752     return 1;
 753
 754   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 755   if (!(attrval = targetm.comp_type_attributes (t1, t2)))
 756      return 0;
 757
 758   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
 759   val = 0;
 760
 761   switch (TREE_CODE (t1))
 762     {
 763     case POINTER_TYPE:
 764       /* Do not remove mode or aliasing information.  */
 765       if (TYPE_MODE (t1) != TYPE_MODE (t2)
 766           || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
 767         break;
 768       val = (TREE_TYPE (t1) == TREE_TYPE (t2)
 769              ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2)));
 770       break;
 771
 772     case FUNCTION_TYPE:
 773       val = function_types_compatible_p (t1, t2);
 774       break;
 775
 776     case ARRAY_TYPE:
 777       {
 778         tree d1 = TYPE_DOMAIN (t1);
 779         tree d2 = TYPE_DOMAIN (t2);
 780         bool d1_variable, d2_variable;
 781         bool d1_zero, d2_zero;
 782         val = 1;
 783
 784         /* Target types must match incl. qualifiers.  */
 785         if (TREE_TYPE (t1) != TREE_TYPE (t2)
 786             && 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2))))
 787           return 0;
 788
 789         /* Sizes must match unless one is missing or variable.  */
 790         if (d1 == 0 || d2 == 0 || d1 == d2)
 791           break;
 792
 793         d1_zero = !TYPE_MAX_VALUE (d1);
 794         d2_zero = !TYPE_MAX_VALUE (d2);
 795
 796         d1_variable = (!d1_zero
 797                        && (TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
 798                            || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST));
 799         d2_variable = (!d2_zero
 800                        && (TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
 801                            || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST));
 802
 803         if (d1_variable || d2_variable)
 804           break;
 805         if (d1_zero && d2_zero)
 806           break;
 807         if (d1_zero || d2_zero
 808             || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 809             || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
 810           val = 0;
 811
 812         break;
 813       }
 814
 815     case ENUMERAL_TYPE:
 816     case RECORD_TYPE:
 817     case UNION_TYPE:
 818       if (val != 1 && !same_translation_unit_p (t1, t2))
 819         {
 820           if (attrval != 2)
 821             return tagged_types_tu_compatible_p (t1, t2);
 822           val = tagged_types_tu_compatible_p (t1, t2);
 823         }
 824       break;
 825
 826     case VECTOR_TYPE:
 827       val = TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
 828             && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2));
 829       break;
 830
 831     default:
 832       break;
 833     }
 834   return attrval == 2 && val == 1 ? 2 : val;
 835 }
 836
 837 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
 838    ignoring their qualifiers.  */
 839
 840 static int
 841 comp_target_types (tree ttl, tree ttr)
 842 {
 843   int val;
 844   tree mvl, mvr;
 845
 846   /* Do not lose qualifiers on element types of array types that are
 847      pointer targets by taking their TYPE_MAIN_VARIANT.  */
 848   mvl = TREE_TYPE (ttl);
 849   mvr = TREE_TYPE (ttr);
 850   if (TREE_CODE (mvl) != ARRAY_TYPE)
 851     mvl = TYPE_MAIN_VARIANT (mvl);
 852   if (TREE_CODE (mvr) != ARRAY_TYPE)
 853     mvr = TYPE_MAIN_VARIANT (mvr);
 854   val = comptypes (mvl, mvr);
 855
 856   if (val == 2 && pedantic)
 857     pedwarn ("types are not quite compatible");
 858   return val;
 859 }
 860 \f
 861 /* Subroutines of `comptypes'.  */
 862
 863 /* Determine whether two trees derive from the same translation unit.
 864    If the CONTEXT chain ends in a null, that tree's context is still
 865    being parsed, so if two trees have context chains ending in null,
 866    they're in the same translation unit.  */
 867 int
 868 same_translation_unit_p (tree t1, tree t2)
 869 {
 870   while (t1 && TREE_CODE (t1) != TRANSLATION_UNIT_DECL)
 871     switch (TREE_CODE_CLASS (TREE_CODE (t1)))
 872       {
 873       case tcc_declaration:
 874         t1 = DECL_CONTEXT (t1); break;
 875       case tcc_type:
 876         t1 = TYPE_CONTEXT (t1); break;
 877       case tcc_exceptional:
 878         t1 = BLOCK_SUPERCONTEXT (t1); break;  /* assume block */
 879       default: gcc_unreachable ();
 880       }
 881
 882   while (t2 && TREE_CODE (t2) != TRANSLATION_UNIT_DECL)
 883     switch (TREE_CODE_CLASS (TREE_CODE (t2)))
 884       {
 885       case tcc_declaration:
 886         t2 = DECL_CONTEXT (t2); break;
 887       case tcc_type:
 888         t2 = TYPE_CONTEXT (t2); break;
 889       case tcc_exceptional:
 890         t2 = BLOCK_SUPERCONTEXT (t2); break;  /* assume block */
 891       default: gcc_unreachable ();
 892       }
 893
 894   return t1 == t2;
 895 }
 896
 897 /* Allocate the seen two types, assuming that they are compatible. */
 898
 899 static struct tagged_tu_seen_cache *
 900 alloc_tagged_tu_seen_cache (tree t1, tree t2)
 901 {
 902   struct tagged_tu_seen_cache *tu = xmalloc (sizeof (struct tagged_tu_seen_cache));
 903   tu->next = tagged_tu_seen_base;
 904   tu->t1 = t1;
 905   tu->t2 = t2;
 906
 907   tagged_tu_seen_base = tu;
 908
 909   /* The C standard says that two structures in different translation
 910      units are compatible with each other only if the types of their
 911      fields are compatible (among other things).  We assume that they
 912      are compatible until proven otherwise when building the cache.
 913      An example where this can occur is:
 914      struct a
 915      {
 916        struct a *next;
 917      };
 918      If we are comparing this against a similar struct in another TU,
 919      and did not assume they were compatible, we end up with an infinite
 920      loop.  */
 921   tu->val = 1;
 922   return tu;
 923 }
 924
 925 /* Free the seen types until we get to TU_TIL. */
 926
 927 static void
 928 free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
 929 {
 930   const struct tagged_tu_seen_cache *tu = tagged_tu_seen_base;
 931   while (tu != tu_til)
 932     {
 933       struct tagged_tu_seen_cache *tu1 = (struct tagged_tu_seen_cache*)tu;
 934       tu = tu1->next;
 935       free (tu1);
 936     }
 937   tagged_tu_seen_base = tu_til;
 938 }
 939
 940 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
 941    compatible.  If the two types are not the same (which has been
 942    checked earlier), this can only happen when multiple translation
 943    units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
 944    rules.  */
 945
 946 static int
 947 tagged_types_tu_compatible_p (tree t1, tree t2)
 948 {
 949   tree s1, s2;
 950   bool needs_warning = false;
 951
 952   /* We have to verify that the tags of the types are the same.  This
 953      is harder than it looks because this may be a typedef, so we have
 954      to go look at the original type.  It may even be a typedef of a
 955      typedef...
 956      In the case of compiler-created builtin structs the TYPE_DECL
 957      may be a dummy, with no DECL_ORIGINAL_TYPE.  Don't fault.  */
 958   while (TYPE_NAME (t1)
 959          && TREE_CODE (TYPE_NAME (t1)) == TYPE_DECL
 960          && DECL_ORIGINAL_TYPE (TYPE_NAME (t1)))
 961     t1 = DECL_ORIGINAL_TYPE (TYPE_NAME (t1));
 962
 963   while (TYPE_NAME (t2)
 964          && TREE_CODE (TYPE_NAME (t2)) == TYPE_DECL
 965          && DECL_ORIGINAL_TYPE (TYPE_NAME (t2)))
 966     t2 = DECL_ORIGINAL_TYPE (TYPE_NAME (t2));
 967
 968   /* C90 didn't have the requirement that the two tags be the same.  */
 969   if (flag_isoc99 && TYPE_NAME (t1) != TYPE_NAME (t2))
 970     return 0;
 971
 972   /* C90 didn't say what happened if one or both of the types were
 973      incomplete; we choose to follow C99 rules here, which is that they
 974      are compatible.  */
 975   if (TYPE_SIZE (t1) == NULL
 976       || TYPE_SIZE (t2) == NULL)
 977     return 1;
 978
 979   {
 980     const struct tagged_tu_seen_cache * tts_i;
 981     for (tts_i = tagged_tu_seen_base; tts_i != NULL; tts_i = tts_i->next)
 982       if (tts_i->t1 == t1 && tts_i->t2 == t2)
 983         return tts_i->val;
 984   }
 985
 986   switch (TREE_CODE (t1))
 987     {
 988     case ENUMERAL_TYPE:
 989       {
 990         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
 991         /* Speed up the case where the type values are in the same order.  */
 992         tree tv1 = TYPE_VALUES (t1);
 993         tree tv2 = TYPE_VALUES (t2);
 994
 995         if (tv1 == tv2)
 996           {
 997             return 1;
 998           }
 999
1000         for (;tv1 && tv2; tv1 = TREE_CHAIN (tv1), tv2 = TREE_CHAIN (tv2))
1001           {
1002             if (TREE_PURPOSE (tv1) != TREE_PURPOSE (tv2))
1003               break;
1004             if (simple_cst_equal (TREE_VALUE (tv1), TREE_VALUE (tv2)) != 1)
1005               {
1006                 tu->val = 0;
1007                 return 0;
1008               }
1009           }
1010
1011         if (tv1 == NULL_TREE && tv2 == NULL_TREE)
1012           {
1013             return 1;
1014           }
1015         if (tv1 == NULL_TREE || tv2 == NULL_TREE)
1016           {
1017             tu->val = 0;
1018             return 0;
1019           }
1020
1021         if (list_length (TYPE_VALUES (t1)) != list_length (TYPE_VALUES (t2)))
1022           {
1023             tu->val = 0;
1024             return 0;
1025           }
1026
1027         for (s1 = TYPE_VALUES (t1); s1; s1 = TREE_CHAIN (s1))
1028           {
1029             s2 = purpose_member (TREE_PURPOSE (s1), TYPE_VALUES (t2));
1030             if (s2 == NULL
1031                 || simple_cst_equal (TREE_VALUE (s1), TREE_VALUE (s2)) != 1)
1032               {
1033                 tu->val = 0;
1034                 return 0;
1035               }
1036           }
1037         return 1;
1038       }
1039
1040     case UNION_TYPE:
1041       {
1042         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1043         if (list_length (TYPE_FIELDS (t1)) != list_length (TYPE_FIELDS (t2)))
1044           {
1045             tu->val = 0;
1046             return 0;
1047           }
1048
1049         /*  Speed up the common case where the fields are in the same order. */
1050         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2); s1 && s2;
1051              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1052           {
1053             int result;
1054
1055
1056             if (DECL_NAME (s1) == NULL
1057                 || DECL_NAME (s1) != DECL_NAME (s2))
1058               break;
1059             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1060             if (result == 0)
1061               {
1062                 tu->val = 0;
1063                 return 0;
1064               }
1065             if (result == 2)
1066               needs_warning = true;
1067
1068             if (TREE_CODE (s1) == FIELD_DECL
1069                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1070                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1071               {
1072                 tu->val = 0;
1073                 return 0;
1074               }
1075           }
1076         if (!s1 && !s2)
1077           {
1078             tu->val = needs_warning ? 2 : 1;
1079             return tu->val;
1080           }
1081
1082         for (s1 = TYPE_FIELDS (t1); s1; s1 = TREE_CHAIN (s1))
1083           {
1084             bool ok = false;
1085
1086             if (DECL_NAME (s1) != NULL)
1087               for (s2 = TYPE_FIELDS (t2); s2; s2 = TREE_CHAIN (s2))
1088                 if (DECL_NAME (s1) == DECL_NAME (s2))
1089                   {
1090                     int result;
1091                     result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1092                     if (result == 0)
1093                       {
1094                         tu->val = 0;
1095                         return 0;
1096                       }
1097                     if (result == 2)
1098                       needs_warning = true;
1099
1100                     if (TREE_CODE (s1) == FIELD_DECL
1101                         && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1102                                              DECL_FIELD_BIT_OFFSET (s2)) != 1)
1103                       break;
1104
1105                     ok = true;
1106                     break;
1107                   }
1108             if (!ok)
1109               {
1110                 tu->val = 0;
1111                 return 0;
1112               }
1113           }
1114         tu->val = needs_warning ? 2 : 10;
1115         return tu->val;
1116       }
1117
1118     case RECORD_TYPE:
1119       {
1120         struct tagged_tu_seen_cache *tu = alloc_tagged_tu_seen_cache (t1, t2);
1121
1122         for (s1 = TYPE_FIELDS (t1), s2 = TYPE_FIELDS (t2);
1123              s1 && s2;
1124              s1 = TREE_CHAIN (s1), s2 = TREE_CHAIN (s2))
1125           {
1126             int result;
1127             if (TREE_CODE (s1) != TREE_CODE (s2)
1128                 || DECL_NAME (s1) != DECL_NAME (s2))
1129               break;
1130             result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2));
1131             if (result == 0)
1132               break;
1133             if (result == 2)
1134               needs_warning = true;
1135
1136             if (TREE_CODE (s1) == FIELD_DECL
1137                 && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
1138                                      DECL_FIELD_BIT_OFFSET (s2)) != 1)
1139               break;
1140           }
1141         if (s1 && s2)
1142           tu->val = 0;
1143         else
1144           tu->val = needs_warning ? 2 : 1;
1145         return tu->val;
1146       }
1147
1148     default:
1149       gcc_unreachable ();
1150     }
1151 }
1152
1153 /* Return 1 if two function types F1 and F2 are compatible.
1154    If either type specifies no argument types,
1155    the other must specify a fixed number of self-promoting arg types.
1156    Otherwise, if one type specifies only the number of arguments,
1157    the other must specify that number of self-promoting arg types.
1158    Otherwise, the argument types must match.  */
1159
1160 static int
1161 function_types_compatible_p (tree f1, tree f2)
1162 {
1163   tree args1, args2;
1164   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1165   int val = 1;
1166   int val1;
1167   tree ret1, ret2;
1168
1169   ret1 = TREE_TYPE (f1);
1170   ret2 = TREE_TYPE (f2);
1171
1172   /* 'volatile' qualifiers on a function's return type used to mean
1173      the function is noreturn.  */
1174   if (TYPE_VOLATILE (ret1) != TYPE_VOLATILE (ret2))
1175     pedwarn ("function return types not compatible due to %<volatile%>");
1176   if (TYPE_VOLATILE (ret1))
1177     ret1 = build_qualified_type (TYPE_MAIN_VARIANT (ret1),
1178                                  TYPE_QUALS (ret1) & ~TYPE_QUAL_VOLATILE);
1179   if (TYPE_VOLATILE (ret2))
1180     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
1181                                  TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
1182   val = comptypes_internal (ret1, ret2);
1183   if (val == 0)
1184     return 0;
1185
1186   args1 = TYPE_ARG_TYPES (f1);
1187   args2 = TYPE_ARG_TYPES (f2);
1188
1189   /* An unspecified parmlist matches any specified parmlist
1190      whose argument types don't need default promotions.  */
1191
1192   if (args1 == 0)
1193     {
1194       if (!self_promoting_args_p (args2))
1195         return 0;
1196       /* If one of these types comes from a non-prototype fn definition,
1197          compare that with the other type's arglist.
1198          If they don't match, ask for a warning (but no error).  */
1199       if (TYPE_ACTUAL_ARG_TYPES (f1)
1200           && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
1201         val = 2;
1202       return val;
1203     }
1204   if (args2 == 0)
1205     {
1206       if (!self_promoting_args_p (args1))
1207         return 0;
1208       if (TYPE_ACTUAL_ARG_TYPES (f2)
1209           && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
1210         val = 2;
1211       return val;
1212     }
1213
1214   /* Both types have argument lists: compare them and propagate results.  */
1215   val1 = type_lists_compatible_p (args1, args2);
1216   return val1 != 1 ? val1 : val;
1217 }
1218
1219 /* Check two lists of types for compatibility,
1220    returning 0 for incompatible, 1 for compatible,
1221    or 2 for compatible with warning.  */
1222
1223 static int
1224 type_lists_compatible_p (tree args1, tree args2)
1225 {
1226   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
1227   int val = 1;
1228   int newval = 0;
1229
1230   while (1)
1231     {
1232       tree a1, mv1, a2, mv2;
1233       if (args1 == 0 && args2 == 0)
1234         return val;
1235       /* If one list is shorter than the other,
1236          they fail to match.  */
1237       if (args1 == 0 || args2 == 0)
1238         return 0;
1239       mv1 = a1 = TREE_VALUE (args1);
1240       mv2 = a2 = TREE_VALUE (args2);
1241       if (mv1 && mv1 != error_mark_node && TREE_CODE (mv1) != ARRAY_TYPE)
1242         mv1 = TYPE_MAIN_VARIANT (mv1);
1243       if (mv2 && mv2 != error_mark_node && TREE_CODE (mv2) != ARRAY_TYPE)
1244         mv2 = TYPE_MAIN_VARIANT (mv2);
1245       /* A null pointer instead of a type
1246          means there is supposed to be an argument
1247          but nothing is specified about what type it has.
1248          So match anything that self-promotes.  */
1249       if (a1 == 0)
1250         {
1251           if (c_type_promotes_to (a2) != a2)
1252             return 0;
1253         }
1254       else if (a2 == 0)
1255         {
1256           if (c_type_promotes_to (a1) != a1)
1257             return 0;
1258         }
1259       /* If one of the lists has an error marker, ignore this arg.  */
1260       else if (TREE_CODE (a1) == ERROR_MARK
1261                || TREE_CODE (a2) == ERROR_MARK)
1262         ;
1263       else if (!(newval = comptypes_internal (mv1, mv2)))
1264         {
1265           /* Allow  wait (union {union wait *u; int *i} *)
1266              and  wait (union wait *)  to be compatible.  */
1267           if (TREE_CODE (a1) == UNION_TYPE
1268               && (TYPE_NAME (a1) == 0
1269                   || TYPE_TRANSPARENT_UNION (a1))
1270               && TREE_CODE (TYPE_SIZE (a1)) == INTEGER_CST
1271               && tree_int_cst_equal (TYPE_SIZE (a1),
1272                                      TYPE_SIZE (a2)))
1273             {
1274               tree memb;
1275               for (memb = TYPE_FIELDS (a1);
1276                    memb; memb = TREE_CHAIN (memb))
1277                 {
1278                   tree mv3 = TREE_TYPE (memb);
1279                   if (mv3 && mv3 != error_mark_node
1280                       && TREE_CODE (mv3) != ARRAY_TYPE)
1281                     mv3 = TYPE_MAIN_VARIANT (mv3);
1282                   if (comptypes_internal (mv3, mv2))
1283                     break;
1284                 }
1285               if (memb == 0)
1286                 return 0;
1287             }
1288           else if (TREE_CODE (a2) == UNION_TYPE
1289                    && (TYPE_NAME (a2) == 0
1290                        || TYPE_TRANSPARENT_UNION (a2))
1291                    && TREE_CODE (TYPE_SIZE (a2)) == INTEGER_CST
1292                    && tree_int_cst_equal (TYPE_SIZE (a2),
1293                                           TYPE_SIZE (a1)))
1294             {
1295               tree memb;
1296               for (memb = TYPE_FIELDS (a2);
1297                    memb; memb = TREE_CHAIN (memb))
1298                 {
1299                   tree mv3 = TREE_TYPE (memb);
1300                   if (mv3 && mv3 != error_mark_node
1301                       && TREE_CODE (mv3) != ARRAY_TYPE)
1302                     mv3 = TYPE_MAIN_VARIANT (mv3);
1303                   if (comptypes_internal (mv3, mv1))
1304                     break;
1305                 }
1306               if (memb == 0)
1307                 return 0;
1308             }
1309           else
1310             return 0;
1311         }
1312
1313       /* comptypes said ok, but record if it said to warn.  */
1314       if (newval > val)
1315         val = newval;
1316
1317       args1 = TREE_CHAIN (args1);
1318       args2 = TREE_CHAIN (args2);
1319     }
1320 }
1321 \f
1322 /* Compute the size to increment a pointer by.  */
1323
1324 static tree
1325 c_size_in_bytes (tree type)
1326 {
1327   enum tree_code code = TREE_CODE (type);
1328
1329   if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
1330     return size_one_node;
1331
1332   if (!COMPLETE_OR_VOID_TYPE_P (type))
1333     {
1334       error ("arithmetic on pointer to an incomplete type");
1335       return size_one_node;
1336     }
1337
1338   /* Convert in case a char is more than one unit.  */
1339   return size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
1340                      size_int (TYPE_PRECISION (char_type_node)
1341                                / BITS_PER_UNIT));
1342 }
1343 \f
1344 /* Return either DECL or its known constant value (if it has one).  */
1345
1346 tree
1347 decl_constant_value (tree decl)
1348 {
1349   if (/* Don't change a variable array bound or initial value to a constant
1350          in a place where a variable is invalid.  Note that DECL_INITIAL
1351          isn't valid for a PARM_DECL.  */
1352       current_function_decl != 0
1353       && TREE_CODE (decl) != PARM_DECL
1354       && !TREE_THIS_VOLATILE (decl)
1355       && TREE_READONLY (decl)
1356       && DECL_INITIAL (decl) != 0
1357       && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
1358       /* This is invalid if initial value is not constant.
1359          If it has either a function call, a memory reference,
1360          or a variable, then re-evaluating it could give different results.  */
1361       && TREE_CONSTANT (DECL_INITIAL (decl))
1362       /* Check for cases where this is sub-optimal, even though valid.  */
1363       && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR)
1364     return DECL_INITIAL (decl);
1365   return decl;
1366 }
1367
1368 /* Return either DECL or its known constant value (if it has one), but
1369    return DECL if pedantic or DECL has mode BLKmode.  This is for
1370    bug-compatibility with the old behavior of decl_constant_value
1371    (before GCC 3.0); every use of this function is a bug and it should
1372    be removed before GCC 3.1.  It is not appropriate to use pedantic
1373    in a way that affects optimization, and BLKmode is probably not the
1374    right test for avoiding misoptimizations either.  */
1375
1376 static tree
1377 decl_constant_value_for_broken_optimization (tree decl)
1378 {
1379   tree ret;
1380
1381   if (pedantic || DECL_MODE (decl) == BLKmode)
1382     return decl;
1383
1384   ret = decl_constant_value (decl);
1385   /* Avoid unwanted tree sharing between the initializer and current
1386      function's body where the tree can be modified e.g. by the
1387      gimplifier.  */
1388   if (ret != decl && TREE_STATIC (decl))
1389     ret = unshare_expr (ret);
1390   return ret;
1391 }
1392
1393 /* Convert the array expression EXP to a pointer.  */
1394 static tree
1395 array_to_pointer_conversion (tree exp)
1396 {
1397   tree orig_exp = exp;
1398   tree type = TREE_TYPE (exp);
1399   tree adr;
1400   tree restype = TREE_TYPE (type);
1401   tree ptrtype;
1402
1403   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1404
1405   STRIP_TYPE_NOPS (exp);
1406
1407   if (TREE_NO_WARNING (orig_exp))
1408     TREE_NO_WARNING (exp) = 1;
1409
1410   ptrtype = build_pointer_type (restype);
1411
1412   if (TREE_CODE (exp) == INDIRECT_REF)
1413     return convert (ptrtype, TREE_OPERAND (exp, 0));
1414
1415   if (TREE_CODE (exp) == VAR_DECL)
1416     {
1417       /* We are making an ADDR_EXPR of ptrtype.  This is a valid
1418          ADDR_EXPR because it's the best way of representing what
1419          happens in C when we take the address of an array and place
1420          it in a pointer to the element type.  */
1421       adr = build1 (ADDR_EXPR, ptrtype, exp);
1422       if (!c_mark_addressable (exp))
1423         return error_mark_node;
1424       TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1425       return adr;
1426     }
1427
1428   /* This way is better for a COMPONENT_REF since it can
1429      simplify the offset for a component.  */
1430   adr = build_unary_op (ADDR_EXPR, exp, 1);
1431   return convert (ptrtype, adr);
1432 }
1433
1434 /* Convert the function expression EXP to a pointer.  */
1435 static tree
1436 function_to_pointer_conversion (tree exp)
1437 {
1438   tree orig_exp = exp;
1439
1440   gcc_assert (TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE);
1441
1442   STRIP_TYPE_NOPS (exp);
1443
1444   if (TREE_NO_WARNING (orig_exp))
1445     TREE_NO_WARNING (exp) = 1;
1446
1447   return build_unary_op (ADDR_EXPR, exp, 0);
1448 }
1449
1450 /* Perform the default conversion of arrays and functions to pointers.
1451    Return the result of converting EXP.  For any other expression, just
1452    return EXP after removing NOPs.  */
1453
1454 struct c_expr
1455 default_function_array_conversion (struct c_expr exp)
1456 {
1457   tree orig_exp = exp.value;
1458   tree type = TREE_TYPE (exp.value);
1459   enum tree_code code = TREE_CODE (type);
1460
1461   switch (code)
1462     {
1463     case ARRAY_TYPE:
1464       {
1465         bool not_lvalue = false;
1466         bool lvalue_array_p;
1467
1468         while ((TREE_CODE (exp.value) == NON_LVALUE_EXPR
1469                 || TREE_CODE (exp.value) == NOP_EXPR)
1470                && TREE_TYPE (TREE_OPERAND (exp.value, 0)) == type)
1471           {
1472             if (TREE_CODE (exp.value) == NON_LVALUE_EXPR)
1473               not_lvalue = true;
1474             exp.value = TREE_OPERAND (exp.value, 0);
1475           }
1476
1477         if (TREE_NO_WARNING (orig_exp))
1478           TREE_NO_WARNING (exp.value) = 1;
1479
1480         lvalue_array_p = !not_lvalue && lvalue_p (exp.value);
1481         if (!flag_isoc99 && !lvalue_array_p)
1482           {
1483             /* Before C99, non-lvalue arrays do not decay to pointers.
1484                Normally, using such an array would be invalid; but it can
1485                be used correctly inside sizeof or as a statement expression.
1486                Thus, do not give an error here; an error will result later.  */
1487             return exp;
1488           }
1489
1490         exp.value = array_to_pointer_conversion (exp.value);
1491       }
1492       break;
1493     case FUNCTION_TYPE:
1494       exp.value = function_to_pointer_conversion (exp.value);
1495       break;
1496     default:
1497       STRIP_TYPE_NOPS (exp.value);
1498       if (TREE_NO_WARNING (orig_exp))
1499         TREE_NO_WARNING (exp.value) = 1;
1500       break;
1501     }
1502
1503   return exp;
1504 }
1505
1506
1507 /* EXP is an expression of integer type.  Apply the integer promotions
1508    to it and return the promoted value.  */
1509
1510 tree
1511 perform_integral_promotions (tree exp)
1512 {
1513   tree type = TREE_TYPE (exp);
1514   enum tree_code code = TREE_CODE (type);
1515
1516   gcc_assert (INTEGRAL_TYPE_P (type));
1517
1518   /* Normally convert enums to int,
1519      but convert wide enums to something wider.  */
1520   if (code == ENUMERAL_TYPE)
1521     {
1522       type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
1523                                           TYPE_PRECISION (integer_type_node)),
1524                                      ((TYPE_PRECISION (type)
1525                                        >= TYPE_PRECISION (integer_type_node))
1526                                       && TYPE_UNSIGNED (type)));
1527
1528       return convert (type, exp);
1529     }
1530
1531   /* ??? This should no longer be needed now bit-fields have their
1532      proper types.  */
1533   if (TREE_CODE (exp) == COMPONENT_REF
1534       && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
1535       /* If it's thinner than an int, promote it like a
1536          c_promoting_integer_type_p, otherwise leave it alone.  */
1537       && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
1538                                TYPE_PRECISION (integer_type_node)))
1539     return convert (integer_type_node, exp);
1540
1541   if (c_promoting_integer_type_p (type))
1542     {
1543       /* Preserve unsignedness if not really getting any wider.  */
1544       if (TYPE_UNSIGNED (type)
1545           && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1546         return convert (unsigned_type_node, exp);
1547
1548       return convert (integer_type_node, exp);
1549     }
1550
1551   return exp;
1552 }
1553
1554
1555 /* Perform default promotions for C data used in expressions.
1556    Enumeral types or short or char are converted to int.
1557    In addition, manifest constants symbols are replaced by their values.  */
1558
1559 tree
1560 default_conversion (tree exp)
1561 {
1562   tree orig_exp;
1563   tree type = TREE_TYPE (exp);
1564   enum tree_code code = TREE_CODE (type);
1565
1566   /* Functions and arrays have been converted during parsing.  */
1567   gcc_assert (code != FUNCTION_TYPE);
1568   if (code == ARRAY_TYPE)
1569     return exp;
1570
1571   /* Constants can be used directly unless they're not loadable.  */
1572   if (TREE_CODE (exp) == CONST_DECL)
1573     exp = DECL_INITIAL (exp);
1574
1575   /* Replace a nonvolatile const static variable with its value unless
1576      it is an array, in which case we must be sure that taking the
1577      address of the array produces consistent results.  */
1578   else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
1579     {
1580       exp = decl_constant_value_for_broken_optimization (exp);
1581       type = TREE_TYPE (exp);
1582     }
1583
1584   /* Strip no-op conversions.  */
1585   orig_exp = exp;
1586   STRIP_TYPE_NOPS (exp);
1587
1588   if (TREE_NO_WARNING (orig_exp))
1589     TREE_NO_WARNING (exp) = 1;
1590
1591   if (INTEGRAL_TYPE_P (type))
1592     return perform_integral_promotions (exp);
1593
1594   if (code == VOID_TYPE)
1595     {
1596       error ("void value not ignored as it ought to be");
1597       return error_mark_node;
1598     }
1599   return exp;
1600 }
1601 \f
1602 /* Look up COMPONENT in a structure or union DECL.
1603
1604    If the component name is not found, returns NULL_TREE.  Otherwise,
1605    the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1606    stepping down the chain to the component, which is in the last
1607    TREE_VALUE of the list.  Normally the list is of length one, but if
1608    the component is embedded within (nested) anonymous structures or
1609    unions, the list steps down the chain to the component.  */
1610
1611 static tree
1612 lookup_field (tree decl, tree component)
1613 {
1614   tree type = TREE_TYPE (decl);
1615   tree field;
1616
1617   /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1618      to the field elements.  Use a binary search on this array to quickly
1619      find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
1620      will always be set for structures which have many elements.  */
1621
1622   if (TYPE_LANG_SPECIFIC (type) && TYPE_LANG_SPECIFIC (type)->s)
1623     {
1624       int bot, top, half;
1625       tree *field_array = &TYPE_LANG_SPECIFIC (type)->s->elts[0];
1626
1627       field = TYPE_FIELDS (type);
1628       bot = 0;
1629       top = TYPE_LANG_SPECIFIC (type)->s->len;
1630       while (top - bot > 1)
1631         {
1632           half = (top - bot + 1) >> 1;
1633           field = field_array[bot+half];
1634
1635           if (DECL_NAME (field) == NULL_TREE)
1636             {
1637               /* Step through all anon unions in linear fashion.  */
1638               while (DECL_NAME (field_array[bot]) == NULL_TREE)
1639                 {
1640                   field = field_array[bot++];
1641                   if (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1642                       || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
1643                     {
1644                       tree anon = lookup_field (field, component);
1645
1646                       if (anon)
1647                         return tree_cons (NULL_TREE, field, anon);
1648                     }
1649                 }
1650
1651               /* Entire record is only anon unions.  */
1652               if (bot > top)
1653                 return NULL_TREE;
1654
1655               /* Restart the binary search, with new lower bound.  */
1656               continue;
1657             }
1658
1659           if (DECL_NAME (field) == component)
1660             break;
1661           if (DECL_NAME (field) < component)
1662             bot += half;
1663           else
1664             top = bot + half;
1665         }
1666
1667       if (DECL_NAME (field_array[bot]) == component)
1668         field = field_array[bot];
1669       else if (DECL_NAME (field) != component)
1670         return NULL_TREE;
1671     }
1672   else
1673     {
1674       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1675         {
1676           if (DECL_NAME (field) == NULL_TREE
1677               && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
1678                   || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
1679             {
1680               tree anon = lookup_field (field, component);
1681
1682               if (anon)
1683                 return tree_cons (NULL_TREE, field, anon);
1684             }
1685
1686           if (DECL_NAME (field) == component)
1687             break;
1688         }
1689
1690       if (field == NULL_TREE)
1691         return NULL_TREE;
1692     }
1693
1694   return tree_cons (NULL_TREE, field, NULL_TREE);
1695 }
1696
1697 /* Make an expression to refer to the COMPONENT field of
1698    structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
1699
1700 tree
1701 build_component_ref (tree datum, tree component)
1702 {
1703   tree type = TREE_TYPE (datum);
1704   enum tree_code code = TREE_CODE (type);
1705   tree field = NULL;
1706   tree ref;
1707
1708   if (!objc_is_public (datum, component))
1709     return error_mark_node;
1710
1711   /* See if there is a field or component with name COMPONENT.  */
1712
1713   if (code == RECORD_TYPE || code == UNION_TYPE)
1714     {
1715       if (!COMPLETE_TYPE_P (type))
1716         {
1717           c_incomplete_type_error (NULL_TREE, type);
1718           return error_mark_node;
1719         }
1720
1721       field = lookup_field (datum, component);
1722
1723       if (!field)
1724         {
1725           error ("%qT has no member named %qE", type, component);
1726           return error_mark_node;
1727         }
1728
1729       /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1730          This might be better solved in future the way the C++ front
1731          end does it - by giving the anonymous entities each a
1732          separate name and type, and then have build_component_ref
1733          recursively call itself.  We can't do that here.  */
1734       do
1735         {
1736           tree subdatum = TREE_VALUE (field);
1737           int quals;
1738           tree subtype;
1739
1740           if (TREE_TYPE (subdatum) == error_mark_node)
1741             return error_mark_node;
1742
1743           quals = TYPE_QUALS (strip_array_types (TREE_TYPE (subdatum)));
1744           quals |= TYPE_QUALS (TREE_TYPE (datum));
1745           subtype = c_build_qualified_type (TREE_TYPE (subdatum), quals);
1746
1747           ref = build3 (COMPONENT_REF, subtype, datum, subdatum,
1748                         NULL_TREE);
1749           if (TREE_READONLY (datum) || TREE_READONLY (subdatum))
1750             TREE_READONLY (ref) = 1;
1751           if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (subdatum))
1752             TREE_THIS_VOLATILE (ref) = 1;
1753
1754           if (TREE_DEPRECATED (subdatum))
1755             warn_deprecated_use (subdatum);
1756
1757           datum = ref;
1758
1759           field = TREE_CHAIN (field);
1760         }
1761       while (field);
1762
1763       return ref;
1764     }
1765   else if (code != ERROR_MARK)
1766     error ("request for member %qE in something not a structure or union",
1767            component);
1768
1769   return error_mark_node;
1770 }
1771 \f
1772 /* Given an expression PTR for a pointer, return an expression
1773    for the value pointed to.
1774    ERRORSTRING is the name of the operator to appear in error messages.  */
1775
1776 tree
1777 build_indirect_ref (tree ptr, const char *errorstring)
1778 {
1779   tree pointer = default_conversion (ptr);
1780   tree type = TREE_TYPE (pointer);
1781
1782   if (TREE_CODE (type) == POINTER_TYPE)
1783     {
1784       if (TREE_CODE (pointer) == ADDR_EXPR
1785           && (TREE_TYPE (TREE_OPERAND (pointer, 0))
1786               == TREE_TYPE (type)))
1787         return TREE_OPERAND (pointer, 0);
1788       else
1789         {
1790           tree t = TREE_TYPE (type);
1791           tree ref;
1792
1793           ref = build1 (INDIRECT_REF, t, pointer);
1794
1795           if (!COMPLETE_OR_VOID_TYPE_P (t) && TREE_CODE (t) != ARRAY_TYPE)
1796             {
1797               error ("dereferencing pointer to incomplete type");
1798               return error_mark_node;
1799             }
1800           if (VOID_TYPE_P (t) && skip_evaluation == 0)
1801             warning (0, "dereferencing %<void *%> pointer");
1802
1803           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1804              so that we get the proper error message if the result is used
1805              to assign to.  Also, &* is supposed to be a no-op.
1806              And ANSI C seems to specify that the type of the result
1807              should be the const type.  */
1808           /* A de-reference of a pointer to const is not a const.  It is valid
1809              to change it via some other pointer.  */
1810           TREE_READONLY (ref) = TYPE_READONLY (t);
1811           TREE_SIDE_EFFECTS (ref)
1812             = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
1813           TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
1814           return ref;
1815         }
1816     }
1817   else if (TREE_CODE (pointer) != ERROR_MARK)
1818     error ("invalid type argument of %qs", errorstring);
1819   return error_mark_node;
1820 }
1821
1822 /* This handles expressions of the form "a[i]", which denotes
1823    an array reference.
1824
1825    This is logically equivalent in C to *(a+i), but we may do it differently.
1826    If A is a variable or a member, we generate a primitive ARRAY_REF.
1827    This avoids forcing the array out of registers, and can work on
1828    arrays that are not lvalues (for example, members of structures returned
1829    by functions).  */
1830
1831 tree
1832 build_array_ref (tree array, tree index)
1833 {
1834   bool swapped = false;
1835   if (TREE_TYPE (array) == error_mark_node
1836       || TREE_TYPE (index) == error_mark_node)
1837     return error_mark_node;
1838
1839   if (TREE_CODE (TREE_TYPE (array)) != ARRAY_TYPE
1840       && TREE_CODE (TREE_TYPE (array)) != POINTER_TYPE)
1841     {
1842       tree temp;
1843       if (TREE_CODE (TREE_TYPE (index)) != ARRAY_TYPE
1844           && TREE_CODE (TREE_TYPE (index)) != POINTER_TYPE)
1845         {
1846           error ("subscripted value is neither array nor pointer");
1847           return error_mark_node;
1848         }
1849       temp = array;
1850       array = index;
1851       index = temp;
1852       swapped = true;
1853     }
1854
1855   if (!INTEGRAL_TYPE_P (TREE_TYPE (index)))
1856     {
1857       error ("array subscript is not an integer");
1858       return error_mark_node;
1859     }
1860
1861   if (TREE_CODE (TREE_TYPE (TREE_TYPE (array))) == FUNCTION_TYPE)
1862     {
1863       error ("subscripted value is pointer to function");
1864       return error_mark_node;
1865     }
1866
1867   /* Subscripting with type char is likely to lose on a machine where
1868      chars are signed.  So warn on any machine, but optionally.  Don't
1869      warn for unsigned char since that type is safe.  Don't warn for
1870      signed char because anyone who uses that must have done so
1871      deliberately.  ??? Existing practice has also been to warn only
1872      when the char index is syntactically the index, not for
1873      char[array].  */
1874   if (!swapped
1875       && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
1876     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
1877
1878   /* Apply default promotions *after* noticing character types.  */
1879   index = default_conversion (index);
1880
1881   gcc_assert (TREE_CODE (TREE_TYPE (index)) == INTEGER_TYPE);
1882
1883   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
1884     {
1885       tree rval, type;
1886
1887       /* An array that is indexed by a non-constant
1888          cannot be stored in a register; we must be able to do
1889          address arithmetic on its address.
1890          Likewise an array of elements of variable size.  */
1891       if (TREE_CODE (index) != INTEGER_CST
1892           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
1893               && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
1894         {
1895           if (!c_mark_addressable (array))
1896             return error_mark_node;
1897         }
1898       /* An array that is indexed by a constant value which is not within
1899          the array bounds cannot be stored in a register either; because we
1900          would get a crash in store_bit_field/extract_bit_field when trying
1901          to access a non-existent part of the register.  */
1902       if (TREE_CODE (index) == INTEGER_CST
1903           && TYPE_DOMAIN (TREE_TYPE (array))
1904           && !int_fits_type_p (index, TYPE_DOMAIN (TREE_TYPE (array))))
1905         {
1906           if (!c_mark_addressable (array))
1907             return error_mark_node;
1908         }
1909
1910       if (pedantic)
1911         {
1912           tree foo = array;
1913           while (TREE_CODE (foo) == COMPONENT_REF)
1914             foo = TREE_OPERAND (foo, 0);
1915           if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
1916             pedwarn ("ISO C forbids subscripting %<register%> array");
1917           else if (!flag_isoc99 && !lvalue_p (foo))
1918             pedwarn ("ISO C90 forbids subscripting non-lvalue array");
1919         }
1920
1921       type = TREE_TYPE (TREE_TYPE (array));
1922       if (TREE_CODE (type) != ARRAY_TYPE)
1923         type = TYPE_MAIN_VARIANT (type);
1924       rval = build4 (ARRAY_REF, type, array, index, NULL_TREE, NULL_TREE);
1925       /* Array ref is const/volatile if the array elements are
1926          or if the array is.  */
1927       TREE_READONLY (rval)
1928         |= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
1929             | TREE_READONLY (array));
1930       TREE_SIDE_EFFECTS (rval)
1931         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1932             | TREE_SIDE_EFFECTS (array));
1933       TREE_THIS_VOLATILE (rval)
1934         |= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
1935             /* This was added by rms on 16 Nov 91.
1936                It fixes  vol struct foo *a;  a->elts[1]
1937                in an inline function.
1938                Hope it doesn't break something else.  */
1939             | TREE_THIS_VOLATILE (array));
1940       return require_complete_type (fold (rval));
1941     }
1942   else
1943     {
1944       tree ar = default_conversion (array);
1945
1946       if (ar == error_mark_node)
1947         return ar;
1948
1949       gcc_assert (TREE_CODE (TREE_TYPE (ar)) == POINTER_TYPE);
1950       gcc_assert (TREE_CODE (TREE_TYPE (TREE_TYPE (ar))) != FUNCTION_TYPE);
1951
1952       return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, index, 0),
1953                                  "array indexing");
1954     }
1955 }
1956 \f
1957 /* Build an external reference to identifier ID.  FUN indicates
1958    whether this will be used for a function call.  LOC is the source
1959    location of the identifier.  */
1960 tree
1961 build_external_ref (tree id, int fun, location_t loc)
1962 {
1963   tree ref;
1964   tree decl = lookup_name (id);
1965
1966   /* In Objective-C, an instance variable (ivar) may be preferred to
1967      whatever lookup_name() found.  */
1968   decl = objc_lookup_ivar (decl, id);
1969
1970   if (decl && decl != error_mark_node)
1971     ref = decl;
1972   else if (fun)
1973     /* Implicit function declaration.  */
1974     ref = implicitly_declare (id);
1975   else if (decl == error_mark_node)
1976     /* Don't complain about something that's already been
1977        complained about.  */
1978     return error_mark_node;
1979   else
1980     {
1981       undeclared_variable (id, loc);
1982       return error_mark_node;
1983     }
1984
1985   if (TREE_TYPE (ref) == error_mark_node)
1986     return error_mark_node;
1987
1988   if (TREE_DEPRECATED (ref))
1989     warn_deprecated_use (ref);
1990
1991   if (!skip_evaluation)
1992     assemble_external (ref);
1993   TREE_USED (ref) = 1;
1994
1995   if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof)
1996     {
1997       if (!in_sizeof && !in_typeof)
1998         C_DECL_USED (ref) = 1;
1999       else if (DECL_INITIAL (ref) == 0
2000                && DECL_EXTERNAL (ref)
2001                && !TREE_PUBLIC (ref))
2002         record_maybe_used_decl (ref);
2003     }
2004
2005   if (TREE_CODE (ref) == CONST_DECL)
2006     {
2007       ref = DECL_INITIAL (ref);
2008       TREE_CONSTANT (ref) = 1;
2009       TREE_INVARIANT (ref) = 1;
2010     }
2011   else if (current_function_decl != 0
2012            && !DECL_FILE_SCOPE_P (current_function_decl)
2013            && (TREE_CODE (ref) == VAR_DECL
2014                || TREE_CODE (ref) == PARM_DECL
2015                || TREE_CODE (ref) == FUNCTION_DECL))
2016     {
2017       tree context = decl_function_context (ref);
2018
2019       if (context != 0 && context != current_function_decl)
2020         DECL_NONLOCAL (ref) = 1;
2021     }
2022
2023   return ref;
2024 }
2025
2026 /* Record details of decls possibly used inside sizeof or typeof.  */
2027 struct maybe_used_decl
2028 {
2029   /* The decl.  */
2030   tree decl;
2031   /* The level seen at (in_sizeof + in_typeof).  */
2032   int level;
2033   /* The next one at this level or above, or NULL.  */
2034   struct maybe_used_decl *next;
2035 };
2036
2037 static struct maybe_used_decl *maybe_used_decls;
2038
2039 /* Record that DECL, an undefined static function reference seen
2040    inside sizeof or typeof, might be used if the operand of sizeof is
2041    a VLA type or the operand of typeof is a variably modified
2042    type.  */
2043
2044 static void
2045 record_maybe_used_decl (tree decl)
2046 {
2047   struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl);
2048   t->decl = decl;
2049   t->level = in_sizeof + in_typeof;
2050   t->next = maybe_used_decls;
2051   maybe_used_decls = t;
2052 }
2053
2054 /* Pop the stack of decls possibly used inside sizeof or typeof.  If
2055    USED is false, just discard them.  If it is true, mark them used
2056    (if no longer inside sizeof or typeof) or move them to the next
2057    level up (if still inside sizeof or typeof).  */
2058
2059 void
2060 pop_maybe_used (bool used)
2061 {
2062   struct maybe_used_decl *p = maybe_used_decls;
2063   int cur_level = in_sizeof + in_typeof;
2064   while (p && p->level > cur_level)
2065     {
2066       if (used)
2067         {
2068           if (cur_level == 0)
2069             C_DECL_USED (p->decl) = 1;
2070           else
2071             p->level = cur_level;
2072         }
2073       p = p->next;
2074     }
2075   if (!used || cur_level == 0)
2076     maybe_used_decls = p;
2077 }
2078
2079 /* Return the result of sizeof applied to EXPR.  */
2080
2081 struct c_expr
2082 c_expr_sizeof_expr (struct c_expr expr)
2083 {
2084   struct c_expr ret;
2085   if (expr.value == error_mark_node)
2086     {
2087       ret.value = error_mark_node;
2088       ret.original_code = ERROR_MARK;
2089       pop_maybe_used (false);
2090     }
2091   else
2092     {
2093       ret.value = c_sizeof (TREE_TYPE (expr.value));
2094       ret.original_code = ERROR_MARK;
2095       pop_maybe_used (C_TYPE_VARIABLE_SIZE (TREE_TYPE (expr.value)));
2096     }
2097   return ret;
2098 }
2099
2100 /* Return the result of sizeof applied to T, a structure for the type
2101    name passed to sizeof (rather than the type itself).  */
2102
2103 struct c_expr
2104 c_expr_sizeof_type (struct c_type_name *t)
2105 {
2106   tree type;
2107   struct c_expr ret;
2108   type = groktypename (t);
2109   ret.value = c_sizeof (type);
2110   ret.original_code = ERROR_MARK;
2111   pop_maybe_used (type != error_mark_node
2112                   ? C_TYPE_VARIABLE_SIZE (type) : false);
2113   return ret;
2114 }
2115
2116 /* Build a function call to function FUNCTION with parameters PARAMS.
2117    PARAMS is a list--a chain of TREE_LIST nodes--in which the
2118    TREE_VALUE of each node is a parameter-expression.
2119    FUNCTION's data type may be a function type or a pointer-to-function.  */
2120
2121 tree
2122 build_function_call (tree function, tree params)
2123 {
2124   tree fntype, fundecl = 0;
2125   tree coerced_params;
2126   tree name = NULL_TREE, result;
2127   tree tem;
2128
2129   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2130   STRIP_TYPE_NOPS (function);
2131
2132   /* Convert anything with function type to a pointer-to-function.  */
2133   if (TREE_CODE (function) == FUNCTION_DECL)
2134     {
2135       /* Implement type-directed function overloading for builtins.
2136          resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2137          handle all the type checking.  The result is a complete expression
2138          that implements this function call.  */
2139       tem = resolve_overloaded_builtin (function, params);
2140       if (tem)
2141         return tem;
2142
2143       name = DECL_NAME (function);
2144       fundecl = function;
2145     }
2146   if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
2147     function = function_to_pointer_conversion (function);
2148
2149   /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2150      expressions, like those used for ObjC messenger dispatches.  */
2151   function = objc_rewrite_function_call (function, params);
2152
2153   fntype = TREE_TYPE (function);
2154
2155   if (TREE_CODE (fntype) == ERROR_MARK)
2156     return error_mark_node;
2157
2158   if (!(TREE_CODE (fntype) == POINTER_TYPE
2159         && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
2160     {
2161       error ("called object %qE is not a function", function);
2162       return error_mark_node;
2163     }
2164
2165   if (fundecl && TREE_THIS_VOLATILE (fundecl))
2166     current_function_returns_abnormally = 1;
2167
2168   /* fntype now gets the type of function pointed to.  */
2169   fntype = TREE_TYPE (fntype);
2170
2171   /* Check that the function is called through a compatible prototype.
2172      If it is not, replace the call by a trap, wrapped up in a compound
2173      expression if necessary.  This has the nice side-effect to prevent
2174      the tree-inliner from generating invalid assignment trees which may
2175      blow up in the RTL expander later.  */
2176   if (TREE_CODE (function) == NOP_EXPR
2177       && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
2178       && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
2179       && !comptypes (fntype, TREE_TYPE (tem)))
2180     {
2181       tree return_type = TREE_TYPE (fntype);
2182       tree trap = build_function_call (built_in_decls[BUILT_IN_TRAP],
2183                                        NULL_TREE);
2184
2185       /* This situation leads to run-time undefined behavior.  We can't,
2186          therefore, simply error unless we can prove that all possible
2187          executions of the program must execute the code.  */
2188       warning (0, "function called through a non-compatible type");
2189
2190       /* We can, however, treat "undefined" any way we please.
2191          Call abort to encourage the user to fix the program.  */
2192       inform ("if this code is reached, the program will abort");
2193
2194       if (VOID_TYPE_P (return_type))
2195         return trap;
2196       else
2197         {
2198           tree rhs;
2199
2200           if (AGGREGATE_TYPE_P (return_type))
2201             rhs = build_compound_literal (return_type,
2202                                           build_constructor (return_type, 0));
2203           else
2204             rhs = fold_build1 (NOP_EXPR, return_type, integer_zero_node);
2205
2206           return build2 (COMPOUND_EXPR, return_type, trap, rhs);
2207         }
2208     }
2209
2210   /* Convert the parameters to the types declared in the
2211      function prototype, or apply default promotions.  */
2212
2213   coerced_params
2214     = convert_arguments (TYPE_ARG_TYPES (fntype), params, function, fundecl);
2215
2216   if (coerced_params == error_mark_node)
2217     return error_mark_node;
2218
2219   /* Check that the arguments to the function are valid.  */
2220
2221   check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params,
2222                             TYPE_ARG_TYPES (fntype));
2223
2224   if (require_constant_value)
2225     {
2226       result = fold_build3_initializer (CALL_EXPR, TREE_TYPE (fntype),
2227                                         function, coerced_params, NULL_TREE);
2228
2229       if (TREE_CONSTANT (result)
2230           && (name == NULL_TREE
2231               || strncmp (IDENTIFIER_POINTER (name), "__builtin_", 10) != 0))
2232         pedwarn_init ("initializer element is not constant");
2233     }
2234   else
2235     result = fold_build3 (CALL_EXPR, TREE_TYPE (fntype),
2236                           function, coerced_params, NULL_TREE);
2237
2238   if (VOID_TYPE_P (TREE_TYPE (result)))
2239     return result;
2240   return require_complete_type (result);
2241 }
2242 \f
2243 /* Convert the argument expressions in the list VALUES
2244    to the types in the list TYPELIST.  The result is a list of converted
2245    argument expressions, unless there are too few arguments in which
2246    case it is error_mark_node.
2247
2248    If TYPELIST is exhausted, or when an element has NULL as its type,
2249    perform the default conversions.
2250
2251    PARMLIST is the chain of parm decls for the function being called.
2252    It may be 0, if that info is not available.
2253    It is used only for generating error messages.
2254
2255    FUNCTION is a tree for the called function.  It is used only for
2256    error messages, where it is formatted with %qE.
2257
2258    This is also where warnings about wrong number of args are generated.
2259
2260    Both VALUES and the returned value are chains of TREE_LIST nodes
2261    with the elements of the list in the TREE_VALUE slots of those nodes.  */
2262
2263 static tree
2264 convert_arguments (tree typelist, tree values, tree function, tree fundecl)
2265 {
2266   tree typetail, valtail;
2267   tree result = NULL;
2268   int parmnum;
2269   tree selector;
2270
2271   /* Change pointer to function to the function itself for
2272      diagnostics.  */
2273   if (TREE_CODE (function) == ADDR_EXPR
2274       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
2275     function = TREE_OPERAND (function, 0);
2276
2277   /* Handle an ObjC selector specially for diagnostics.  */
2278   selector = objc_message_selector ();
2279
2280   /* Scan the given expressions and types, producing individual
2281      converted arguments and pushing them on RESULT in reverse order.  */
2282
2283   for (valtail = values, typetail = typelist, parmnum = 0;
2284        valtail;
2285        valtail = TREE_CHAIN (valtail), parmnum++)
2286     {
2287       tree type = typetail ? TREE_VALUE (typetail) : 0;
2288       tree val = TREE_VALUE (valtail);
2289       tree rname = function;
2290       int argnum = parmnum + 1;
2291       const char *invalid_func_diag;
2292
2293       if (type == void_type_node)
2294         {
2295           error ("too many arguments to function %qE", function);
2296           break;
2297         }
2298
2299       if (selector && argnum > 2)
2300         {
2301           rname = selector;
2302           argnum -= 2;
2303         }
2304
2305       STRIP_TYPE_NOPS (val);
2306
2307       val = require_complete_type (val);
2308
2309       if (type != 0)
2310         {
2311           /* Formal parm type is specified by a function prototype.  */
2312           tree parmval;
2313
2314           if (type == error_mark_node || !COMPLETE_TYPE_P (type))
2315             {
2316               error ("type of formal parameter %d is incomplete", parmnum + 1);
2317               parmval = val;
2318             }
2319           else
2320             {
2321               /* Optionally warn about conversions that
2322                  differ from the default conversions.  */
2323               if (warn_conversion || warn_traditional)
2324                 {
2325                   unsigned int formal_prec = TYPE_PRECISION (type);
2326
2327                   if (INTEGRAL_TYPE_P (type)
2328                       && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2329                     warning (0, "passing argument %d of %qE as integer "
2330                              "rather than floating due to prototype",
2331                              argnum, rname);
2332                   if (INTEGRAL_TYPE_P (type)
2333                       && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2334                     warning (0, "passing argument %d of %qE as integer "
2335                              "rather than complex due to prototype",
2336                              argnum, rname);
2337                   else if (TREE_CODE (type) == COMPLEX_TYPE
2338                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2339                     warning (0, "passing argument %d of %qE as complex "
2340                              "rather than floating due to prototype",
2341                              argnum, rname);
2342                   else if (TREE_CODE (type) == REAL_TYPE
2343                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2344                     warning (0, "passing argument %d of %qE as floating "
2345                              "rather than integer due to prototype",
2346                              argnum, rname);
2347                   else if (TREE_CODE (type) == COMPLEX_TYPE
2348                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2349                     warning (0, "passing argument %d of %qE as complex "
2350                              "rather than integer due to prototype",
2351                              argnum, rname);
2352                   else if (TREE_CODE (type) == REAL_TYPE
2353                            && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
2354                     warning (0, "passing argument %d of %qE as floating "
2355                              "rather than complex due to prototype",
2356                              argnum, rname);
2357                   /* ??? At some point, messages should be written about
2358                      conversions between complex types, but that's too messy
2359                      to do now.  */
2360                   else if (TREE_CODE (type) == REAL_TYPE
2361                            && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
2362                     {
2363                       /* Warn if any argument is passed as `float',
2364                          since without a prototype it would be `double'.  */
2365                       if (formal_prec == TYPE_PRECISION (float_type_node))
2366                         warning (0, "passing argument %d of %qE as %<float%> "
2367                                  "rather than %<double%> due to prototype",
2368                                  argnum, rname);
2369                     }
2370                   /* Detect integer changing in width or signedness.
2371                      These warnings are only activated with
2372                      -Wconversion, not with -Wtraditional.  */
2373                   else if (warn_conversion && INTEGRAL_TYPE_P (type)
2374                            && INTEGRAL_TYPE_P (TREE_TYPE (val)))
2375                     {
2376                       tree would_have_been = default_conversion (val);
2377                       tree type1 = TREE_TYPE (would_have_been);
2378
2379                       if (TREE_CODE (type) == ENUMERAL_TYPE
2380                           && (TYPE_MAIN_VARIANT (type)
2381                               == TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2382                         /* No warning if function asks for enum
2383                            and the actual arg is that enum type.  */
2384                         ;
2385                       else if (formal_prec != TYPE_PRECISION (type1))
2386                         warning (OPT_Wconversion, "passing argument %d of %qE "
2387                                  "with different width due to prototype",
2388                                  argnum, rname);
2389                       else if (TYPE_UNSIGNED (type) == TYPE_UNSIGNED (type1))
2390                         ;
2391                       /* Don't complain if the formal parameter type
2392                          is an enum, because we can't tell now whether
2393                          the value was an enum--even the same enum.  */
2394                       else if (TREE_CODE (type) == ENUMERAL_TYPE)
2395                         ;
2396                       else if (TREE_CODE (val) == INTEGER_CST
2397                                && int_fits_type_p (val, type))
2398                         /* Change in signedness doesn't matter
2399                            if a constant value is unaffected.  */
2400                         ;
2401                       /* If the value is extended from a narrower
2402                          unsigned type, it doesn't matter whether we
2403                          pass it as signed or unsigned; the value
2404                          certainly is the same either way.  */
2405                       else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
2406                                && TYPE_UNSIGNED (TREE_TYPE (val)))
2407                         ;
2408                       else if (TYPE_UNSIGNED (type))
2409                         warning (OPT_Wconversion, "passing argument %d of %qE "
2410                                  "as unsigned due to prototype",
2411                                  argnum, rname);
2412                       else
2413                         warning (OPT_Wconversion, "passing argument %d of %qE "
2414                                  "as signed due to prototype", argnum, rname);
2415                     }
2416                 }
2417
2418               parmval = convert_for_assignment (type, val, ic_argpass,
2419                                                 fundecl, function,
2420                                                 parmnum + 1);
2421
2422               if (targetm.calls.promote_prototypes (fundecl ? TREE_TYPE (fundecl) : 0)
2423                   && INTEGRAL_TYPE_P (type)
2424                   && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
2425                 parmval = default_conversion (parmval);
2426             }
2427           result = tree_cons (NULL_TREE, parmval, result);
2428         }
2429       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
2430                && (TYPE_PRECISION (TREE_TYPE (val))
2431                    < TYPE_PRECISION (double_type_node)))
2432         /* Convert `float' to `double'.  */
2433         result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
2434       else if ((invalid_func_diag =
2435                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
2436         {
2437           error (invalid_func_diag);
2438           return error_mark_node;
2439         }
2440       else
2441         /* Convert `short' and `char' to full-size `int'.  */
2442         result = tree_cons (NULL_TREE, default_conversion (val), result);
2443
2444       if (typetail)
2445         typetail = TREE_CHAIN (typetail);
2446     }
2447
2448   if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
2449     {
2450       error ("too few arguments to function %qE", function);
2451       return error_mark_node;
2452     }
2453
2454   return nreverse (result);
2455 }
2456 \f
2457 /* This is the entry point used by the parser to build unary operators
2458    in the input.  CODE, a tree_code, specifies the unary operator, and
2459    ARG is the operand.  For unary plus, the C parser currently uses
2460    CONVERT_EXPR for code.  */
2461
2462 struct c_expr
2463 parser_build_unary_op (enum tree_code code, struct c_expr arg)
2464 {
2465   struct c_expr result;
2466
2467   result.original_code = ERROR_MARK;
2468   result.value = build_unary_op (code, arg.value, 0);
2469   overflow_warning (result.value);
2470   return result;
2471 }
2472
2473 /* This is the entry point used by the parser to build binary operators
2474    in the input.  CODE, a tree_code, specifies the binary operator, and
2475    ARG1 and ARG2 are the operands.  In addition to constructing the
2476    expression, we check for operands that were written with other binary
2477    operators in a way that is likely to confuse the user.  */
2478
2479 struct c_expr
2480 parser_build_binary_op (enum tree_code code, struct c_expr arg1,
2481                         struct c_expr arg2)
2482 {
2483   struct c_expr result;
2484
2485   enum tree_code code1 = arg1.original_code;
2486   enum tree_code code2 = arg2.original_code;
2487
2488   result.value = build_binary_op (code, arg1.value, arg2.value, 1);
2489   result.original_code = code;
2490
2491   if (TREE_CODE (result.value) == ERROR_MARK)
2492     return result;
2493
2494   /* Check for cases such as x+y<<z which users are likely
2495      to misinterpret.  */
2496   if (warn_parentheses)
2497     {
2498       if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
2499         {
2500           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2501               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2502             warning (OPT_Wparentheses,
2503                      "suggest parentheses around + or - inside shift");
2504         }
2505
2506       if (code == TRUTH_ORIF_EXPR)
2507         {
2508           if (code1 == TRUTH_ANDIF_EXPR
2509               || code2 == TRUTH_ANDIF_EXPR)
2510             warning (OPT_Wparentheses,
2511                      "suggest parentheses around && within ||");
2512         }
2513
2514       if (code == BIT_IOR_EXPR)
2515         {
2516           if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
2517               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2518               || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
2519               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2520             warning (OPT_Wparentheses,
2521                      "suggest parentheses around arithmetic in operand of |");
2522           /* Check cases like x|y==z */
2523           if (TREE_CODE_CLASS (code1) == tcc_comparison
2524               || TREE_CODE_CLASS (code2) == tcc_comparison)
2525             warning (OPT_Wparentheses,
2526                      "suggest parentheses around comparison in operand of |");
2527         }
2528
2529       if (code == BIT_XOR_EXPR)
2530         {
2531           if (code1 == BIT_AND_EXPR
2532               || code1 == PLUS_EXPR || code1 == MINUS_EXPR
2533               || code2 == BIT_AND_EXPR
2534               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2535             warning (OPT_Wparentheses,
2536                      "suggest parentheses around arithmetic in operand of ^");
2537           /* Check cases like x^y==z */
2538           if (TREE_CODE_CLASS (code1) == tcc_comparison
2539               || TREE_CODE_CLASS (code2) == tcc_comparison)
2540             warning (OPT_Wparentheses,
2541                      "suggest parentheses around comparison in operand of ^");
2542         }
2543
2544       if (code == BIT_AND_EXPR)
2545         {
2546           if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
2547               || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
2548             warning (OPT_Wparentheses,
2549                      "suggest parentheses around + or - in operand of &");
2550           /* Check cases like x&y==z */
2551           if (TREE_CODE_CLASS (code1) == tcc_comparison
2552               || TREE_CODE_CLASS (code2) == tcc_comparison)
2553             warning (OPT_Wparentheses,
2554                      "suggest parentheses around comparison in operand of &");
2555         }
2556       /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
2557       if (TREE_CODE_CLASS (code) == tcc_comparison
2558           && (TREE_CODE_CLASS (code1) == tcc_comparison
2559               || TREE_CODE_CLASS (code2) == tcc_comparison))
2560         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
2561                  "have their mathematical meaning");
2562
2563     }
2564
2565   unsigned_conversion_warning (result.value, arg1.value);
2566   unsigned_conversion_warning (result.value, arg2.value);
2567   overflow_warning (result.value);
2568
2569   return result;
2570 }
2571 \f
2572 /* Return a tree for the difference of pointers OP0 and OP1.
2573    The resulting tree has type int.  */
2574
2575 static tree
2576 pointer_diff (tree op0, tree op1)
2577 {
2578   tree restype = ptrdiff_type_node;
2579
2580   tree target_type = TREE_TYPE (TREE_TYPE (op0));
2581   tree con0, con1, lit0, lit1;
2582   tree orig_op1 = op1;
2583
2584   if (pedantic || warn_pointer_arith)
2585     {
2586       if (TREE_CODE (target_type) == VOID_TYPE)
2587         pedwarn ("pointer of type %<void *%> used in subtraction");
2588       if (TREE_CODE (target_type) == FUNCTION_TYPE)
2589         pedwarn ("pointer to a function used in subtraction");
2590     }
2591
2592   /* If the conversion to ptrdiff_type does anything like widening or
2593      converting a partial to an integral mode, we get a convert_expression
2594      that is in the way to do any simplifications.
2595      (fold-const.c doesn't know that the extra bits won't be needed.
2596      split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2597      different mode in place.)
2598      So first try to find a common term here 'by hand'; we want to cover
2599      at least the cases that occur in legal static initializers.  */
2600   con0 = TREE_CODE (op0) == NOP_EXPR ? TREE_OPERAND (op0, 0) : op0;
2601   con1 = TREE_CODE (op1) == NOP_EXPR ? TREE_OPERAND (op1, 0) : op1;
2602
2603   if (TREE_CODE (con0) == PLUS_EXPR)
2604     {
2605       lit0 = TREE_OPERAND (con0, 1);
2606       con0 = TREE_OPERAND (con0, 0);
2607     }
2608   else
2609     lit0 = integer_zero_node;
2610
2611   if (TREE_CODE (con1) == PLUS_EXPR)
2612     {
2613       lit1 = TREE_OPERAND (con1, 1);
2614       con1 = TREE_OPERAND (con1, 0);
2615     }
2616   else
2617     lit1 = integer_zero_node;
2618
2619   if (operand_equal_p (con0, con1, 0))
2620     {
2621       op0 = lit0;
2622       op1 = lit1;
2623     }
2624
2625
2626   /* First do the subtraction as integers;
2627      then drop through to build the divide operator.
2628      Do not do default conversions on the minus operator
2629      in case restype is a short type.  */
2630
2631   op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
2632                          convert (restype, op1), 0);
2633   /* This generates an error if op1 is pointer to incomplete type.  */
2634   if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
2635     error ("arithmetic on pointer to an incomplete type");
2636
2637   /* This generates an error if op0 is pointer to incomplete type.  */
2638   op1 = c_size_in_bytes (target_type);
2639
2640   /* Divide by the size, in easiest possible way.  */
2641   return fold_build2 (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
2642 }
2643 \f
2644 /* Construct and perhaps optimize a tree representation
2645    for a unary operation.  CODE, a tree_code, specifies the operation
2646    and XARG is the operand.
2647    For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2648    the default promotions (such as from short to int).
2649    For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2650    allows non-lvalues; this is only used to handle conversion of non-lvalue
2651    arrays to pointers in C99.  */
2652
2653 tree
2654 build_unary_op (enum tree_code code, tree xarg, int flag)
2655 {
2656   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
2657   tree arg = xarg;
2658   tree argtype = 0;
2659   enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
2660   tree val;
2661   int noconvert = flag;
2662   const char *invalid_op_diag;
2663
2664   if (typecode == ERROR_MARK)
2665     return error_mark_node;
2666   if (typecode == ENUMERAL_TYPE || typecode == BOOLEAN_TYPE)
2667     typecode = INTEGER_TYPE;
2668
2669   if ((invalid_op_diag
2670        = targetm.invalid_unary_op (code, TREE_TYPE (xarg))))
2671     {
2672       error (invalid_op_diag);
2673       return error_mark_node;
2674     }
2675
2676   switch (code)
2677     {
2678     case CONVERT_EXPR:
2679       /* This is used for unary plus, because a CONVERT_EXPR
2680          is enough to prevent anybody from looking inside for
2681          associativity, but won't generate any code.  */
2682       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2683             || typecode == COMPLEX_TYPE
2684             || typecode == VECTOR_TYPE))
2685         {
2686           error ("wrong type argument to unary plus");
2687           return error_mark_node;
2688         }
2689       else if (!noconvert)
2690         arg = default_conversion (arg);
2691       arg = non_lvalue (arg);
2692       break;
2693
2694     case NEGATE_EXPR:
2695       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2696             || typecode == COMPLEX_TYPE
2697             || typecode == VECTOR_TYPE))
2698         {
2699           error ("wrong type argument to unary minus");
2700           return error_mark_node;
2701         }
2702       else if (!noconvert)
2703         arg = default_conversion (arg);
2704       break;
2705
2706     case BIT_NOT_EXPR:
2707       if (typecode == INTEGER_TYPE || typecode == VECTOR_TYPE)
2708         {
2709           if (!noconvert)
2710             arg = default_conversion (arg);
2711         }
2712       else if (typecode == COMPLEX_TYPE)
2713         {
2714           code = CONJ_EXPR;
2715           if (pedantic)
2716             pedwarn ("ISO C does not support %<~%> for complex conjugation");
2717           if (!noconvert)
2718             arg = default_conversion (arg);
2719         }
2720       else
2721         {
2722           error ("wrong type argument to bit-complement");
2723           return error_mark_node;
2724         }
2725       break;
2726
2727     case ABS_EXPR:
2728       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
2729         {
2730           error ("wrong type argument to abs");
2731           return error_mark_node;
2732         }
2733       else if (!noconvert)
2734         arg = default_conversion (arg);
2735       break;
2736
2737     case CONJ_EXPR:
2738       /* Conjugating a real value is a no-op, but allow it anyway.  */
2739       if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
2740             || typecode == COMPLEX_TYPE))
2741         {
2742           error ("wrong type argument to conjugation");
2743           return error_mark_node;
2744         }
2745       else if (!noconvert)
2746         arg = default_conversion (arg);
2747       break;
2748
2749     case TRUTH_NOT_EXPR:
2750       if (typecode != INTEGER_TYPE
2751           && typecode != REAL_TYPE && typecode != POINTER_TYPE
2752           && typecode != COMPLEX_TYPE)
2753         {
2754           error ("wrong type argument to unary exclamation mark");
2755           return error_mark_node;
2756         }
2757       arg = c_objc_common_truthvalue_conversion (arg);
2758       return invert_truthvalue (arg);
2759
2760     case NOP_EXPR:
2761       break;
2762
2763     case REALPART_EXPR:
2764       if (TREE_CODE (arg) == COMPLEX_CST)
2765         return TREE_REALPART (arg);
2766       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2767         return fold_build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2768       else
2769         return arg;
2770
2771     case IMAGPART_EXPR:
2772       if (TREE_CODE (arg) == COMPLEX_CST)
2773         return TREE_IMAGPART (arg);
2774       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
2775         return fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
2776       else
2777         return convert (TREE_TYPE (arg), integer_zero_node);
2778
2779     case PREINCREMENT_EXPR:
2780     case POSTINCREMENT_EXPR:
2781     case PREDECREMENT_EXPR:
2782     case POSTDECREMENT_EXPR:
2783
2784       /* Increment or decrement the real part of the value,
2785          and don't change the imaginary part.  */
2786       if (typecode == COMPLEX_TYPE)
2787         {
2788           tree real, imag;
2789
2790           if (pedantic)
2791             pedwarn ("ISO C does not support %<++%> and %<--%>"
2792                      " on complex types");
2793
2794           arg = stabilize_reference (arg);
2795           real = build_unary_op (REALPART_EXPR, arg, 1);
2796           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
2797           return build2 (COMPLEX_EXPR, TREE_TYPE (arg),
2798                          build_unary_op (code, real, 1), imag);
2799         }
2800
2801       /* Report invalid types.  */
2802
2803       if (typecode != POINTER_TYPE
2804           && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
2805         {
2806           if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2807             error ("wrong type argument to increment");
2808           else
2809             error ("wrong type argument to decrement");
2810
2811           return error_mark_node;
2812         }
2813
2814       {
2815         tree inc;
2816         tree result_type = TREE_TYPE (arg);
2817
2818         arg = get_unwidened (arg, 0);
2819         argtype = TREE_TYPE (arg);
2820
2821         /* Compute the increment.  */
2822
2823         if (typecode == POINTER_TYPE)
2824           {
2825             /* If pointer target is an undefined struct,
2826                we just cannot know how to do the arithmetic.  */
2827             if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (result_type)))
2828               {
2829                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2830                   error ("increment of pointer to unknown structure");
2831                 else
2832                   error ("decrement of pointer to unknown structure");
2833               }
2834             else if ((pedantic || warn_pointer_arith)
2835                      && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
2836                          || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
2837               {
2838                 if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
2839                   pedwarn ("wrong type argument to increment");
2840                 else
2841                   pedwarn ("wrong type argument to decrement");
2842               }
2843
2844             inc = c_size_in_bytes (TREE_TYPE (result_type));
2845           }
2846         else
2847           inc = integer_one_node;
2848
2849         inc = convert (argtype, inc);
2850
2851         /* Complain about anything else that is not a true lvalue.  */
2852         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
2853                                     || code == POSTINCREMENT_EXPR)
2854                                    ? lv_increment
2855                                    : lv_decrement)))
2856           return error_mark_node;
2857
2858         /* Report a read-only lvalue.  */
2859         if (TREE_READONLY (arg))
2860           readonly_error (arg,
2861                           ((code == PREINCREMENT_EXPR
2862                             || code == POSTINCREMENT_EXPR)
2863                            ? lv_increment : lv_decrement));
2864
2865         if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
2866           val = boolean_increment (code, arg);
2867         else
2868           val = build2 (code, TREE_TYPE (arg), arg, inc);
2869         TREE_SIDE_EFFECTS (val) = 1;
2870         val = convert (result_type, val);
2871         if (TREE_CODE (val) != code)
2872           TREE_NO_WARNING (val) = 1;
2873         return val;
2874       }
2875
2876     case ADDR_EXPR:
2877       /* Note that this operation never does default_conversion.  */
2878
2879       /* Let &* cancel out to simplify resulting code.  */
2880       if (TREE_CODE (arg) == INDIRECT_REF)
2881         {
2882           /* Don't let this be an lvalue.  */
2883           if (lvalue_p (TREE_OPERAND (arg, 0)))
2884             return non_lvalue (TREE_OPERAND (arg, 0));
2885           return TREE_OPERAND (arg, 0);
2886         }
2887
2888       /* For &x[y], return x+y */
2889       if (TREE_CODE (arg) == ARRAY_REF)
2890         {
2891           tree op0 = TREE_OPERAND (arg, 0);
2892           if (!c_mark_addressable (op0))
2893             return error_mark_node;
2894           return build_binary_op (PLUS_EXPR,
2895                                   (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
2896                                    ? array_to_pointer_conversion (op0)
2897                                    : op0),
2898                                   TREE_OPERAND (arg, 1), 1);
2899         }
2900
2901       /* Anything not already handled and not a true memory reference
2902          or a non-lvalue array is an error.  */
2903       else if (typecode != FUNCTION_TYPE && !flag
2904                && !lvalue_or_else (arg, lv_addressof))
2905         return error_mark_node;
2906
2907       /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
2908       argtype = TREE_TYPE (arg);
2909
2910       /* If the lvalue is const or volatile, merge that into the type
2911          to which the address will point.  Note that you can't get a
2912          restricted pointer by taking the address of something, so we
2913          only have to deal with `const' and `volatile' here.  */
2914       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
2915           && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
2916           argtype = c_build_type_variant (argtype,
2917                                           TREE_READONLY (arg),
2918                                           TREE_THIS_VOLATILE (arg));
2919
2920       if (!c_mark_addressable (arg))
2921         return error_mark_node;
2922
2923       gcc_assert (TREE_CODE (arg) != COMPONENT_REF
2924                   || !DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)));
2925
2926       argtype = build_pointer_type (argtype);
2927
2928       /* ??? Cope with user tricks that amount to offsetof.  Delete this
2929          when we have proper support for integer constant expressions.  */
2930       val = get_base_address (arg);
2931       if (val && TREE_CODE (val) == INDIRECT_REF
2932           && TREE_CONSTANT (TREE_OPERAND (val, 0)))
2933         {
2934           tree op0 = fold_convert (argtype, fold_offsetof (arg)), op1;
2935
2936           op1 = fold_convert (argtype, TREE_OPERAND (val, 0));
2937           return fold_build2 (PLUS_EXPR, argtype, op0, op1);
2938         }
2939
2940       val = build1 (ADDR_EXPR, argtype, arg);
2941
2942       return val;
2943
2944     default:
2945       break;
2946     }
2947
2948   if (argtype == 0)
2949     argtype = TREE_TYPE (arg);
2950   return require_constant_value ? fold_build1_initializer (code, argtype, arg)
2951                                 : fold_build1 (code, argtype, arg);
2952 }
2953
2954 /* Return nonzero if REF is an lvalue valid for this language.
2955    Lvalues can be assigned, unless their type has TYPE_READONLY.
2956    Lvalues can have their address taken, unless they have C_DECL_REGISTER.  */
2957
2958 static int
2959 lvalue_p (tree ref)
2960 {
2961   enum tree_code code = TREE_CODE (ref);
2962
2963   switch (code)
2964     {
2965     case REALPART_EXPR:
2966     case IMAGPART_EXPR:
2967     case COMPONENT_REF:
2968       return lvalue_p (TREE_OPERAND (ref, 0));
2969
2970     case COMPOUND_LITERAL_EXPR:
2971     case STRING_CST:
2972       return 1;
2973
2974     case INDIRECT_REF:
2975     case ARRAY_REF:
2976     case VAR_DECL:
2977     case PARM_DECL:
2978     case RESULT_DECL:
2979     case ERROR_MARK:
2980       return (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
2981               && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE);
2982
2983     case BIND_EXPR:
2984       return TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE;
2985
2986     default:
2987       return 0;
2988     }
2989 }
2990 \f
2991 /* Give an error for storing in something that is 'const'.  */
2992
2993 static void
2994 readonly_error (tree arg, enum lvalue_use use)
2995 {
2996   gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement
2997               || use == lv_asm);
2998   /* Using this macro rather than (for example) arrays of messages
2999      ensures that all the format strings are checked at compile
3000      time.  */
3001 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A)               \
3002                                    : (use == lv_increment ? (I)         \
3003                                    : (use == lv_decrement ? (D) : (AS))))
3004   if (TREE_CODE (arg) == COMPONENT_REF)
3005     {
3006       if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
3007         readonly_error (TREE_OPERAND (arg, 0), use);
3008       else
3009         error (READONLY_MSG (G_("assignment of read-only member %qD"),
3010                              G_("increment of read-only member %qD"),
3011                              G_("decrement of read-only member %qD"),
3012                              G_("read-only member %qD used as %<asm%> output")),
3013                TREE_OPERAND (arg, 1));
3014     }
3015   else if (TREE_CODE (arg) == VAR_DECL)
3016     error (READONLY_MSG (G_("assignment of read-only variable %qD"),
3017                          G_("increment of read-only variable %qD"),
3018                          G_("decrement of read-only variable %qD"),
3019                          G_("read-only variable %qD used as %<asm%> output")),
3020            arg);
3021   else
3022     error (READONLY_MSG (G_("assignment of read-only location"),
3023                          G_("increment of read-only location"),
3024                          G_("decrement of read-only location"),
3025                          G_("read-only location used as %<asm%> output")));
3026 }
3027
3028
3029 /* Return nonzero if REF is an lvalue valid for this language;
3030    otherwise, print an error message and return zero.  USE says
3031    how the lvalue is being used and so selects the error message.  */
3032
3033 static int
3034 lvalue_or_else (tree ref, enum lvalue_use use)
3035 {
3036   int win = lvalue_p (ref);
3037
3038   if (!win)
3039     lvalue_error (use);
3040
3041   return win;
3042 }
3043 \f
3044 /* Mark EXP saying that we need to be able to take the
3045    address of it; it should not be allocated in a register.
3046    Returns true if successful.  */
3047
3048 bool
3049 c_mark_addressable (tree exp)
3050 {
3051   tree x = exp;
3052
3053   while (1)
3054     switch (TREE_CODE (x))
3055       {
3056       case COMPONENT_REF:
3057         if (DECL_C_BIT_FIELD (TREE_OPERAND (x, 1)))
3058           {
3059             error
3060               ("cannot take address of bit-field %qD", TREE_OPERAND (x, 1));
3061             return false;
3062           }
3063
3064         /* ... fall through ...  */
3065
3066       case ADDR_EXPR:
3067       case ARRAY_REF:
3068       case REALPART_EXPR:
3069       case IMAGPART_EXPR:
3070         x = TREE_OPERAND (x, 0);
3071         break;
3072
3073       case COMPOUND_LITERAL_EXPR:
3074       case CONSTRUCTOR:
3075         TREE_ADDRESSABLE (x) = 1;
3076         return true;
3077
3078       case VAR_DECL:
3079       case CONST_DECL:
3080       case PARM_DECL:
3081       case RESULT_DECL:
3082         if (C_DECL_REGISTER (x)
3083             && DECL_NONLOCAL (x))
3084           {
3085             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3086               {
3087                 error
3088                   ("global register variable %qD used in nested function", x);
3089                 return false;
3090               }
3091             pedwarn ("register variable %qD used in nested function", x);
3092           }
3093         else if (C_DECL_REGISTER (x))
3094           {
3095             if (TREE_PUBLIC (x) || TREE_STATIC (x) || DECL_EXTERNAL (x))
3096               error ("address of global register variable %qD requested", x);
3097             else
3098               error ("address of register variable %qD requested", x);
3099             return false;
3100           }
3101
3102         /* drops in */
3103       case FUNCTION_DECL:
3104         TREE_ADDRESSABLE (x) = 1;
3105         /* drops out */
3106       default:
3107         return true;
3108     }
3109 }
3110 \f
3111 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
3112
3113 tree
3114 build_conditional_expr (tree ifexp, tree op1, tree op2)
3115 {
3116   tree type1;
3117   tree type2;
3118   enum tree_code code1;
3119   enum tree_code code2;
3120   tree result_type = NULL;
3121   tree orig_op1 = op1, orig_op2 = op2;
3122
3123   /* Promote both alternatives.  */
3124
3125   if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
3126     op1 = default_conversion (op1);
3127   if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
3128     op2 = default_conversion (op2);
3129
3130   if (TREE_CODE (ifexp) == ERROR_MARK
3131       || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
3132       || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
3133     return error_mark_node;
3134
3135   type1 = TREE_TYPE (op1);
3136   code1 = TREE_CODE (type1);
3137   type2 = TREE_TYPE (op2);
3138   code2 = TREE_CODE (type2);
3139
3140   /* C90 does not permit non-lvalue arrays in conditional expressions.
3141      In C99 they will be pointers by now.  */
3142   if (code1 == ARRAY_TYPE || code2 == ARRAY_TYPE)
3143     {
3144       error ("non-lvalue array in conditional expression");
3145       return error_mark_node;
3146     }
3147
3148   /* Quickly detect the usual case where op1 and op2 have the same type
3149      after promotion.  */
3150   if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
3151     {
3152       if (type1 == type2)
3153         result_type = type1;
3154       else
3155         result_type = TYPE_MAIN_VARIANT (type1);
3156     }
3157   else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE
3158             || code1 == COMPLEX_TYPE)
3159            && (code2 == INTEGER_TYPE || code2 == REAL_TYPE
3160                || code2 == COMPLEX_TYPE))
3161     {
3162       result_type = c_common_type (type1, type2);
3163
3164       /* If -Wsign-compare, warn here if type1 and type2 have
3165          different signedness.  We'll promote the signed to unsigned
3166          and later code won't know it used to be different.
3167          Do this check on the original types, so that explicit casts
3168          will be considered, but default promotions won't.  */
3169       if (warn_sign_compare && !skip_evaluation)
3170         {
3171           int unsigned_op1 = TYPE_UNSIGNED (TREE_TYPE (orig_op1));
3172           int unsigned_op2 = TYPE_UNSIGNED (TREE_TYPE (orig_op2));
3173
3174           if (unsigned_op1 ^ unsigned_op2)
3175             {
3176               /* Do not warn if the result type is signed, since the
3177                  signed type will only be chosen if it can represent
3178                  all the values of the unsigned type.  */
3179               if (!TYPE_UNSIGNED (result_type))
3180                 /* OK */;
3181               /* Do not warn if the signed quantity is an unsuffixed
3182                  integer literal (or some static constant expression
3183                  involving such literals) and it is non-negative.  */
3184               else if ((unsigned_op2 && tree_expr_nonnegative_p (op1))
3185                        || (unsigned_op1 && tree_expr_nonnegative_p (op2)))
3186                 /* OK */;
3187               else
3188                 warning (0, "signed and unsigned type in conditional expression");
3189             }
3190         }
3191     }
3192   else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
3193     {
3194       if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
3195         pedwarn ("ISO C forbids conditional expr with only one void side");
3196       result_type = void_type_node;
3197     }
3198   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
3199     {
3200       if (comp_target_types (type1, type2))
3201         result_type = common_pointer_type (type1, type2);
3202       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
3203                && TREE_CODE (orig_op1) != NOP_EXPR)
3204         result_type = qualify_type (type2, type1);
3205       else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
3206                && TREE_CODE (orig_op2) != NOP_EXPR)
3207         result_type = qualify_type (type1, type2);
3208       else if (VOID_TYPE_P (TREE_TYPE (type1)))
3209         {
3210           if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
3211             pedwarn ("ISO C forbids conditional expr between "
3212                      "%<void *%> and function pointer");
3213           result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
3214                                                           TREE_TYPE (type2)));
3215         }
3216       else if (VOID_TYPE_P (TREE_TYPE (type2)))
3217         {
3218           if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
3219             pedwarn ("ISO C forbids conditional expr between "
3220                      "%<void *%> and function pointer");
3221           result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
3222                                                           TREE_TYPE (type1)));
3223         }
3224       else
3225         {
3226           pedwarn ("pointer type mismatch in conditional expression");
3227           result_type = build_pointer_type (void_type_node);
3228         }
3229     }
3230   else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
3231     {
3232       if (!integer_zerop (op2))
3233         pedwarn ("pointer/integer type mismatch in conditional expression");
3234       else
3235         {
3236           op2 = null_pointer_node;
3237         }
3238       result_type = type1;
3239     }
3240   else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
3241     {
3242       if (!integer_zerop (op1))
3243         pedwarn ("pointer/integer type mismatch in conditional expression");
3244       else
3245         {
3246           op1 = null_pointer_node;
3247         }
3248       result_type = type2;
3249     }
3250
3251   if (!result_type)
3252     {
3253       if (flag_cond_mismatch)
3254         result_type = void_type_node;
3255       else
3256         {
3257           error ("type mismatch in conditional expression");
3258           return error_mark_node;
3259         }
3260     }
3261
3262   /* Merge const and volatile flags of the incoming types.  */
3263   result_type
3264     = build_type_variant (result_type,
3265                           TREE_READONLY (op1) || TREE_READONLY (op2),
3266                           TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
3267
3268   if (result_type != TREE_TYPE (op1))
3269     op1 = convert_and_check (result_type, op1);
3270   if (result_type != TREE_TYPE (op2))
3271     op2 = convert_and_check (result_type, op2);
3272
3273   return fold_build3 (COND_EXPR, result_type, ifexp, op1, op2);
3274 }
3275 \f
3276 /* Return a compound expression that performs two expressions and
3277    returns the value of the second of them.  */
3278
3279 tree
3280 build_compound_expr (tree expr1, tree expr2)
3281 {
3282   if (!TREE_SIDE_EFFECTS (expr1))
3283     {
3284       /* The left-hand operand of a comma expression is like an expression
3285          statement: with -Wextra or -Wunused, we should warn if it doesn't have
3286          any side-effects, unless it was explicitly cast to (void).  */
3287       if (warn_unused_value)
3288         {
3289           if (VOID_TYPE_P (TREE_TYPE (expr1))
3290               && TREE_CODE (expr1) == CONVERT_EXPR)
3291             ; /* (void) a, b */
3292           else if (VOID_TYPE_P (TREE_TYPE (expr1))
3293                    && TREE_CODE (expr1) == COMPOUND_EXPR
3294                    && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
3295             ; /* (void) a, (void) b, c */
3296           else
3297             warning (0, "left-hand operand of comma expression has no effect");
3298         }
3299     }
3300
3301   /* With -Wunused, we should also warn if the left-hand operand does have
3302      side-effects, but computes a value which is not used.  For example, in
3303      `foo() + bar(), baz()' the result of the `+' operator is not used,
3304      so we should issue a warning.  */
3305   else if (warn_unused_value)
3306     warn_if_unused_value (expr1, input_location);
3307
3308   if (expr2 == error_mark_node)
3309     return error_mark_node;
3310
3311   return build2 (COMPOUND_EXPR, TREE_TYPE (expr2), expr1, expr2);
3312 }
3313
3314 /* Build an expression representing a cast to type TYPE of expression EXPR.  */
3315
3316 tree
3317 build_c_cast (tree type, tree expr)
3318 {
3319   tree value = expr;
3320
3321   if (type == error_mark_node || expr == error_mark_node)
3322     return error_mark_node;
3323
3324   /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3325      only in <protocol> qualifications.  But when constructing cast expressions,
3326      the protocols do matter and must be kept around.  */
3327   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
3328     return build1 (NOP_EXPR, type, expr);
3329
3330   type = TYPE_MAIN_VARIANT (type);
3331
3332   if (TREE_CODE (type) == ARRAY_TYPE)
3333     {
3334       error ("cast specifies array type");
3335       return error_mark_node;
3336     }
3337
3338   if (TREE_CODE (type) == FUNCTION_TYPE)
3339     {
3340       error ("cast specifies function type");
3341       return error_mark_node;
3342     }
3343
3344   if (type == TYPE_MAIN_VARIANT (TREE_TYPE (value)))
3345     {
3346       if (pedantic)
3347         {
3348           if (TREE_CODE (type) == RECORD_TYPE
3349               || TREE_CODE (type) == UNION_TYPE)
3350             pedwarn ("ISO C forbids casting nonscalar to the same type");
3351         }
3352     }
3353   else if (TREE_CODE (type) == UNION_TYPE)
3354     {
3355       tree field;
3356
3357       for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
3358         if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
3359                        TYPE_MAIN_VARIANT (TREE_TYPE (value))))
3360           break;
3361
3362       if (field)
3363         {
3364           tree t;
3365
3366           if (pedantic)
3367             pedwarn ("ISO C forbids casts to union type");
3368           t = digest_init (type,
3369                            build_constructor_single (type, field, value),
3370                            true, 0);
3371           TREE_CONSTANT (t) = TREE_CONSTANT (value);
3372           TREE_INVARIANT (t) = TREE_INVARIANT (value);
3373           return t;
3374         }
3375       error ("cast to union type from type not present in union");
3376       return error_mark_node;
3377     }
3378   else
3379     {
3380       tree otype, ovalue;
3381
3382       if (type == void_type_node)
3383         return build1 (CONVERT_EXPR, type, value);
3384
3385       otype = TREE_TYPE (value);
3386
3387       /* Optionally warn about potentially worrisome casts.  */
3388
3389       if (warn_cast_qual
3390           && TREE_CODE (type) == POINTER_TYPE
3391           && TREE_CODE (otype) == POINTER_TYPE)
3392         {
3393           tree in_type = type;
3394           tree in_otype = otype;
3395           int added = 0;
3396           int discarded = 0;
3397
3398           /* Check that the qualifiers on IN_TYPE are a superset of
3399              the qualifiers of IN_OTYPE.  The outermost level of
3400              POINTER_TYPE nodes is uninteresting and we stop as soon
3401              as we hit a non-POINTER_TYPE node on either type.  */
3402           do
3403             {
3404               in_otype = TREE_TYPE (in_otype);
3405               in_type = TREE_TYPE (in_type);
3406
3407               /* GNU C allows cv-qualified function types.  'const'
3408                  means the function is very pure, 'volatile' means it
3409                  can't return.  We need to warn when such qualifiers
3410                  are added, not when they're taken away.  */
3411               if (TREE_CODE (in_otype) == FUNCTION_TYPE
3412                   && TREE_CODE (in_type) == FUNCTION_TYPE)
3413                 added |= (TYPE_QUALS (in_type) & ~TYPE_QUALS (in_otype));
3414               else
3415                 discarded |= (TYPE_QUALS (in_otype) & ~TYPE_QUALS (in_type));
3416             }
3417           while (TREE_CODE (in_type) == POINTER_TYPE
3418                  && TREE_CODE (in_otype) == POINTER_TYPE);
3419
3420           if (added)
3421             warning (0, "cast adds new qualifiers to function type");
3422
3423           if (discarded)
3424             /* There are qualifiers present in IN_OTYPE that are not
3425                present in IN_TYPE.  */
3426             warning (0, "cast discards qualifiers from pointer target type");
3427         }
3428
3429       /* Warn about possible alignment problems.  */
3430       if (STRICT_ALIGNMENT
3431           && TREE_CODE (type) == POINTER_TYPE
3432           && TREE_CODE (otype) == POINTER_TYPE
3433           && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
3434           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3435           /* Don't warn about opaque types, where the actual alignment
3436              restriction is unknown.  */
3437           && !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
3438                 || TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
3439                && TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
3440           && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
3441         warning (OPT_Wcast_align,
3442                  "cast increases required alignment of target type");
3443
3444       if (TREE_CODE (type) == INTEGER_TYPE
3445           && TREE_CODE (otype) == POINTER_TYPE
3446           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3447           && !TREE_CONSTANT (value))
3448         warning (OPT_Wpointer_to_int_cast,
3449                  "cast from pointer to integer of different size");
3450
3451       if (TREE_CODE (value) == CALL_EXPR
3452           && TREE_CODE (type) != TREE_CODE (otype))
3453         warning (OPT_Wbad_function_cast, "cast from function call of type %qT "
3454                  "to non-matching type %qT", otype, type);
3455
3456       if (TREE_CODE (type) == POINTER_TYPE
3457           && TREE_CODE (otype) == INTEGER_TYPE
3458           && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
3459           /* Don't warn about converting any constant.  */
3460           && !TREE_CONSTANT (value))
3461         warning (OPT_Wint_to_pointer_cast, "cast to pointer from integer "
3462                  "of different size");
3463
3464       strict_aliasing_warning (otype, type, expr);
3465
3466       /* If pedantic, warn for conversions between function and object
3467          pointer types, except for converting a null pointer constant
3468          to function pointer type.  */
3469       if (pedantic
3470           && TREE_CODE (type) == POINTER_TYPE
3471           && TREE_CODE (otype) == POINTER_TYPE
3472           && TREE_CODE (TREE_TYPE (otype)) == FUNCTION_TYPE
3473           && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)
3474         pedwarn ("ISO C forbids conversion of function pointer to object pointer type");
3475
3476       if (pedantic
3477           && TREE_CODE (type) == POINTER_TYPE
3478           && TREE_CODE (otype) == POINTER_TYPE
3479           && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
3480           && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
3481           && !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node
3482                && TREE_CODE (expr) != NOP_EXPR))
3483         pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
3484
3485       ovalue = value;
3486       value = convert (type, value);
3487
3488       /* Ignore any integer overflow caused by the cast.  */
3489       if (TREE_CODE (value) == INTEGER_CST)
3490         {
3491           if (CONSTANT_CLASS_P (ovalue)
3492               && (TREE_OVERFLOW (ovalue) || TREE_CONSTANT_OVERFLOW (ovalue)))
3493             {
3494               /* Avoid clobbering a shared constant.  */
3495               value = copy_node (value);
3496               TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
3497               TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
3498             }
3499           else if (TREE_OVERFLOW (value) || TREE_CONSTANT_OVERFLOW (value))
3500             /* Reset VALUE's overflow flags, ensuring constant sharing.  */
3501             value = build_int_cst_wide (TREE_TYPE (value),
3502                                         TREE_INT_CST_LOW (value),
3503                                         TREE_INT_CST_HIGH (value));
3504         }
3505     }
3506
3507   /* Don't let a cast be an lvalue.  */
3508   if (value == expr)
3509     value = non_lvalue (value);
3510
3511   return value;
3512 }
3513
3514 /* Interpret a cast of expression EXPR to type TYPE.  */
3515 tree
3516 c_cast_expr (struct c_type_name *type_name, tree expr)
3517 {
3518   tree type;
3519   int saved_wsp = warn_strict_prototypes;
3520
3521   /* This avoids warnings about unprototyped casts on
3522      integers.  E.g. "#define SIG_DFL (void(*)())0".  */
3523   if (TREE_CODE (expr) == INTEGER_CST)
3524     warn_strict_prototypes = 0;
3525   type = groktypename (type_name);
3526   warn_strict_prototypes = saved_wsp;
3527
3528   return build_c_cast (type, expr);
3529 }
3530
3531 \f
3532 /* Build an assignment expression of lvalue LHS from value RHS.
3533    MODIFYCODE is the code for a binary operator that we use
3534    to combine the old value of LHS with RHS to get the new value.
3535    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
3536
3537 tree
3538 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
3539 {
3540   tree result;
3541   tree newrhs;
3542   tree lhstype = TREE_TYPE (lhs);
3543   tree olhstype = lhstype;
3544
3545   /* Types that aren't fully specified cannot be used in assignments.  */
3546   lhs = require_complete_type (lhs);
3547
3548   /* Avoid duplicate error messages from operands that had errors.  */
3549   if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
3550     return error_mark_node;
3551
3552   if (!lvalue_or_else (lhs, lv_assign))
3553     return error_mark_node;
3554
3555   STRIP_TYPE_NOPS (rhs);
3556
3557   newrhs = rhs;
3558
3559   /* If a binary op has been requested, combine the old LHS value with the RHS
3560      producing the value we should actually store into the LHS.  */
3561
3562   if (modifycode != NOP_EXPR)
3563     {
3564       lhs = stabilize_reference (lhs);
3565       newrhs = build_binary_op (modifycode, lhs, rhs, 1);
3566     }
3567
3568   /* Give an error for storing in something that is 'const'.  */
3569
3570   if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
3571       || ((TREE_CODE (lhstype) == RECORD_TYPE
3572            || TREE_CODE (lhstype) == UNION_TYPE)
3573           && C_TYPE_FIELDS_READONLY (lhstype)))
3574     readonly_error (lhs, lv_assign);
3575
3576   /* If storing into a structure or union member,
3577      it has probably been given type `int'.
3578      Compute the type that would go with
3579      the actual amount of storage the member occupies.  */
3580
3581   if (TREE_CODE (lhs) == COMPONENT_REF
3582       && (TREE_CODE (lhstype) == INTEGER_TYPE
3583           || TREE_CODE (lhstype) == BOOLEAN_TYPE
3584           || TREE_CODE (lhstype) == REAL_TYPE
3585           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
3586     lhstype = TREE_TYPE (get_unwidened (lhs, 0));
3587
3588   /* If storing in a field that is in actuality a short or narrower than one,
3589      we must store in the field in its actual type.  */
3590
3591   if (lhstype != TREE_TYPE (lhs))
3592     {
3593       lhs = copy_node (lhs);
3594       TREE_TYPE (lhs) = lhstype;
3595     }
3596
3597   /* Convert new value to destination type.  */
3598
3599   newrhs = convert_for_assignment (lhstype, newrhs, ic_assign,
3600                                    NULL_TREE, NULL_TREE, 0);
3601   if (TREE_CODE (newrhs) == ERROR_MARK)
3602     return error_mark_node;
3603
3604   /* Emit ObjC write barrier, if necessary.  */
3605   if (c_dialect_objc () && flag_objc_gc)
3606     {
3607       result = objc_generate_write_barrier (lhs, modifycode, newrhs);
3608       if (result)
3609         return result;
3610     }
3611
3612   /* Scan operands.  */
3613
3614   result = build2 (MODIFY_EXPR, lhstype, lhs, newrhs);
3615   TREE_SIDE_EFFECTS (result) = 1;
3616
3617   /* If we got the LHS in a different type for storing in,
3618      convert the result back to the nominal type of LHS
3619      so that the value we return always has the same type
3620      as the LHS argument.  */
3621
3622   if (olhstype == TREE_TYPE (result))
3623     return result;
3624   return convert_for_assignment (olhstype, result, ic_assign,
3625                                  NULL_TREE, NULL_TREE, 0);
3626 }
3627 \f
3628 /* Convert value RHS to type TYPE as preparation for an assignment
3629    to an lvalue of type TYPE.
3630    The real work of conversion is done by `convert'.
3631    The purpose of this function is to generate error messages
3632    for assignments that are not allowed in C.
3633    ERRTYPE says whether it is argument passing, assignment,
3634    initialization or return.
3635
3636    FUNCTION is a tree for the function being called.
3637    PARMNUM is the number of the argument, for printing in error messages.  */
3638
3639 static tree
3640 convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
3641                         tree fundecl, tree function, int parmnum)
3642 {
3643   enum tree_code codel = TREE_CODE (type);
3644   tree rhstype;
3645   enum tree_code coder;
3646   tree rname = NULL_TREE;
3647   bool objc_ok = false;
3648
3649   if (errtype == ic_argpass || errtype == ic_argpass_nonproto)
3650     {
3651       tree selector;
3652       /* Change pointer to function to the function itself for
3653          diagnostics.  */
3654       if (TREE_CODE (function) == ADDR_EXPR
3655           && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL)
3656         function = TREE_OPERAND (function, 0);
3657
3658       /* Handle an ObjC selector specially for diagnostics.  */
3659       selector = objc_message_selector ();
3660       rname = function;
3661       if (selector && parmnum > 2)
3662         {
3663           rname = selector;
3664           parmnum -= 2;
3665         }
3666     }
3667
3668   /* This macro is used to emit diagnostics to ensure that all format
3669      strings are complete sentences, visible to gettext and checked at
3670      compile time.  */
3671 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE)     \
3672   do {                                          \
3673     switch (errtype)                            \
3674       {                                         \
3675       case ic_argpass:                          \
3676         pedwarn (AR, parmnum, rname);           \
3677         break;                                  \
3678       case ic_argpass_nonproto:                 \
3679         warning (0, AR, parmnum, rname);                \
3680         break;                                  \
3681       case ic_assign:                           \
3682         pedwarn (AS);                           \
3683         break;                                  \
3684       case ic_init:                             \
3685         pedwarn (IN);                           \
3686         break;                                  \
3687       case ic_return:                           \
3688         pedwarn (RE);                           \
3689         break;                                  \
3690       default:                                  \
3691         gcc_unreachable ();                     \
3692       }                                         \
3693   } while (0)
3694
3695   STRIP_TYPE_NOPS (rhs);
3696
3697   if (optimize && TREE_CODE (rhs) == VAR_DECL
3698            && TREE_CODE (TREE_TYPE (rhs)) != ARRAY_TYPE)
3699     rhs = decl_constant_value_for_broken_optimization (rhs);
3700
3701   rhstype = TREE_TYPE (rhs);
3702   coder = TREE_CODE (rhstype);
3703
3704   if (coder == ERROR_MARK)
3705     return error_mark_node;
3706
3707   if (c_dialect_objc ())
3708     {
3709       int parmno;
3710
3711       switch (errtype)
3712         {
3713         case ic_return:
3714           parmno = 0;
3715           break;
3716
3717         case ic_assign:
3718           parmno = -1;
3719           break;
3720
3721         case ic_init:
3722           parmno = -2;
3723           break;
3724
3725         default:
3726           parmno = parmnum;
3727           break;
3728         }
3729
3730       objc_ok = objc_compare_types (type, rhstype, parmno, rname);
3731     }
3732
3733   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
3734     {
3735       overflow_warning (rhs);
3736       return rhs;
3737     }
3738
3739   if (coder == VOID_TYPE)
3740     {
3741       /* Except for passing an argument to an unprototyped function,
3742          this is a constraint violation.  When passing an argument to
3743          an unprototyped function, it is compile-time undefined;
3744          making it a constraint in that case was rejected in
3745          DR#252.  */
3746       error ("void value not ignored as it ought to be");
3747       return error_mark_node;
3748     }
3749   /* A type converts to a reference to it.
3750      This code doesn't fully support references, it's just for the
3751      special case of va_start and va_copy.  */
3752   if (codel == REFERENCE_TYPE
3753       && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
3754     {
3755       if (!lvalue_p (rhs))
3756         {
3757           error ("cannot pass rvalue to reference parameter");
3758           return error_mark_node;
3759         }
3760       if (!c_mark_addressable (rhs))
3761         return error_mark_node;
3762       rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
3763
3764       /* We already know that these two types are compatible, but they
3765          may not be exactly identical.  In fact, `TREE_TYPE (type)' is
3766          likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3767          likely to be va_list, a typedef to __builtin_va_list, which
3768          is different enough that it will cause problems later.  */
3769       if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
3770         rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
3771
3772       rhs = build1 (NOP_EXPR, type, rhs);
3773       return rhs;
3774     }
3775   /* Some types can interconvert without explicit casts.  */
3776   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
3777            && vector_types_convertible_p (type, TREE_TYPE (rhs)))
3778     return convert (type, rhs);
3779   /* Arithmetic types all interconvert, and enum is treated like int.  */
3780   else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
3781             || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
3782             || codel == BOOLEAN_TYPE)
3783            && (coder == INTEGER_TYPE || coder == REAL_TYPE
3784                || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE
3785                || coder == BOOLEAN_TYPE))
3786     return convert_and_check (type, rhs);
3787
3788   /* Conversion to a transparent union from its member types.
3789      This applies only to function arguments.  */
3790   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
3791            && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
3792     {
3793       tree memb, marginal_memb = NULL_TREE;
3794
3795       for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
3796         {
3797           tree memb_type = TREE_TYPE (memb);
3798
3799           if (comptypes (TYPE_MAIN_VARIANT (memb_type),
3800                          TYPE_MAIN_VARIANT (rhstype)))
3801             break;
3802
3803           if (TREE_CODE (memb_type) != POINTER_TYPE)
3804             continue;
3805
3806           if (coder == POINTER_TYPE)
3807             {
3808               tree ttl = TREE_TYPE (memb_type);
3809               tree ttr = TREE_TYPE (rhstype);
3810
3811               /* Any non-function converts to a [const][volatile] void *
3812                  and vice versa; otherwise, targets must be the same.
3813                  Meanwhile, the lhs target must have all the qualifiers of
3814                  the rhs.  */
3815               if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3816                   || comp_target_types (memb_type, rhstype))
3817                 {
3818                   /* If this type won't generate any warnings, use it.  */
3819                   if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
3820                       || ((TREE_CODE (ttr) == FUNCTION_TYPE
3821                            && TREE_CODE (ttl) == FUNCTION_TYPE)
3822                           ? ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3823                              == TYPE_QUALS (ttr))
3824                           : ((TYPE_QUALS (ttl) | TYPE_QUALS (ttr))
3825                              == TYPE_QUALS (ttl))))
3826                     break;
3827
3828                   /* Keep looking for a better type, but remember this one.  */
3829                   if (!marginal_memb)
3830                     marginal_memb = memb;
3831                 }
3832             }
3833
3834           /* Can convert integer zero to any pointer type.  */
3835           if (integer_zerop (rhs)
3836               || (TREE_CODE (rhs) == NOP_EXPR
3837                   && integer_zerop (TREE_OPERAND (rhs, 0))))
3838             {
3839               rhs = null_pointer_node;
3840               break;
3841             }
3842         }
3843
3844       if (memb || marginal_memb)
3845         {
3846           if (!memb)
3847             {
3848               /* We have only a marginally acceptable member type;
3849                  it needs a warning.  */
3850               tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
3851               tree ttr = TREE_TYPE (rhstype);
3852
3853               /* Const and volatile mean something different for function
3854                  types, so the usual warnings are not appropriate.  */
3855               if (TREE_CODE (ttr) == FUNCTION_TYPE
3856                   && TREE_CODE (ttl) == FUNCTION_TYPE)
3857                 {
3858                   /* Because const and volatile on functions are
3859                      restrictions that say the function will not do
3860                      certain things, it is okay to use a const or volatile
3861                      function where an ordinary one is wanted, but not
3862                      vice-versa.  */
3863                   if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
3864                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE "
3865                                             "makes qualified function "
3866                                             "pointer from unqualified"),
3867                                          G_("assignment makes qualified "
3868                                             "function pointer from "
3869                                             "unqualified"),
3870                                          G_("initialization makes qualified "
3871                                             "function pointer from "
3872                                             "unqualified"),
3873                                          G_("return makes qualified function "
3874                                             "pointer from unqualified"));
3875                 }
3876               else if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3877                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
3878                                         "qualifiers from pointer target type"),
3879                                      G_("assignment discards qualifiers "
3880                                         "from pointer target type"),
3881                                      G_("initialization discards qualifiers "
3882                                         "from pointer target type"),
3883                                      G_("return discards qualifiers from "
3884                                         "pointer target type"));
3885
3886               memb = marginal_memb;
3887             }
3888
3889           if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
3890             pedwarn ("ISO C prohibits argument conversion to union type");
3891
3892           return build_constructor_single (type, memb, rhs);
3893         }
3894     }
3895
3896   /* Conversions among pointers */
3897   else if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
3898            && (coder == codel))
3899     {
3900       tree ttl = TREE_TYPE (type);
3901       tree ttr = TREE_TYPE (rhstype);
3902       tree mvl = ttl;
3903       tree mvr = ttr;
3904       bool is_opaque_pointer;
3905       int target_cmp = 0;   /* Cache comp_target_types () result.  */
3906
3907       if (TREE_CODE (mvl) != ARRAY_TYPE)
3908         mvl = TYPE_MAIN_VARIANT (mvl);
3909       if (TREE_CODE (mvr) != ARRAY_TYPE)
3910         mvr = TYPE_MAIN_VARIANT (mvr);
3911       /* Opaque pointers are treated like void pointers.  */
3912       is_opaque_pointer = (targetm.vector_opaque_p (type)
3913                            || targetm.vector_opaque_p (rhstype))
3914         && TREE_CODE (ttl) == VECTOR_TYPE
3915         && TREE_CODE (ttr) == VECTOR_TYPE;
3916
3917       /* C++ does not allow the implicit conversion void* -> T*.  However,
3918          for the purpose of reducing the number of false positives, we
3919          tolerate the special case of
3920
3921                 int *p = NULL;
3922
3923          where NULL is typically defined in C to be '(void *) 0'.  */
3924       if (VOID_TYPE_P (ttr) && rhs != null_pointer_node && !VOID_TYPE_P (ttl))
3925         warning (OPT_Wc___compat, "request for implicit conversion from "
3926                  "%qT to %qT not permitted in C++", rhstype, type);
3927
3928       /* Check if the right-hand side has a format attribute but the
3929          left-hand side doesn't.  */
3930       if (warn_missing_format_attribute
3931           && check_missing_format_attribute (type, rhstype))
3932         {
3933           switch (errtype)
3934           {
3935           case ic_argpass:
3936           case ic_argpass_nonproto:
3937             warning (OPT_Wmissing_format_attribute,
3938                      "argument %d of %qE might be "
3939                      "a candidate for a format attribute",
3940                      parmnum, rname);
3941             break;
3942           case ic_assign:
3943             warning (OPT_Wmissing_format_attribute,
3944                      "assignment left-hand side might be "
3945                      "a candidate for a format attribute");
3946             break;
3947           case ic_init:
3948             warning (OPT_Wmissing_format_attribute,
3949                      "initialization left-hand side might be "
3950                      "a candidate for a format attribute");
3951             break;
3952           case ic_return:
3953             warning (OPT_Wmissing_format_attribute,
3954                      "return type might be "
3955                      "a candidate for a format attribute");
3956             break;
3957           default:
3958             gcc_unreachable ();
3959           }
3960         }
3961
3962       /* Any non-function converts to a [const][volatile] void *
3963          and vice versa; otherwise, targets must be the same.
3964          Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
3965       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
3966           || (target_cmp = comp_target_types (type, rhstype))
3967           || is_opaque_pointer
3968           || (c_common_unsigned_type (mvl)
3969               == c_common_unsigned_type (mvr)))
3970         {
3971           if (pedantic
3972               && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
3973                   ||
3974                   (VOID_TYPE_P (ttr)
3975                    /* Check TREE_CODE to catch cases like (void *) (char *) 0
3976                       which are not ANSI null ptr constants.  */
3977                    && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
3978                    && TREE_CODE (ttl) == FUNCTION_TYPE)))
3979             WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
3980                                     "%qE between function pointer "
3981                                     "and %<void *%>"),
3982                                  G_("ISO C forbids assignment between "
3983                                     "function pointer and %<void *%>"),
3984                                  G_("ISO C forbids initialization between "
3985                                     "function pointer and %<void *%>"),
3986                                  G_("ISO C forbids return between function "
3987                                     "pointer and %<void *%>"));
3988           /* Const and volatile mean something different for function types,
3989              so the usual warnings are not appropriate.  */
3990           else if (TREE_CODE (ttr) != FUNCTION_TYPE
3991                    && TREE_CODE (ttl) != FUNCTION_TYPE)
3992             {
3993               if (TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl))
3994                 {
3995                   /* Types differing only by the presence of the 'volatile'
3996                      qualifier are acceptable if the 'volatile' has been added
3997                      in by the Objective-C EH machinery.  */
3998                   if (!objc_type_quals_match (ttl, ttr))
3999                     WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE discards "
4000                                             "qualifiers from pointer target type"),
4001                                          G_("assignment discards qualifiers "
4002                                             "from pointer target type"),
4003                                          G_("initialization discards qualifiers "
4004                                             "from pointer target type"),
4005                                          G_("return discards qualifiers from "
4006                                             "pointer target type"));
4007                 }
4008               /* If this is not a case of ignoring a mismatch in signedness,
4009                  no warning.  */
4010               else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
4011                        || target_cmp)
4012                 ;
4013               /* If there is a mismatch, do warn.  */
4014               else if (warn_pointer_sign)
4015                 WARN_FOR_ASSIGNMENT (G_("pointer targets in passing argument "
4016                                         "%d of %qE differ in signedness"),
4017                                      G_("pointer targets in assignment "
4018                                         "differ in signedness"),
4019                                      G_("pointer targets in initialization "
4020                                         "differ in signedness"),
4021                                      G_("pointer targets in return differ "
4022                                         "in signedness"));
4023             }
4024           else if (TREE_CODE (ttl) == FUNCTION_TYPE
4025                    && TREE_CODE (ttr) == FUNCTION_TYPE)
4026             {
4027               /* Because const and volatile on functions are restrictions
4028                  that say the function will not do certain things,
4029                  it is okay to use a const or volatile function
4030                  where an ordinary one is wanted, but not vice-versa.  */
4031               if (TYPE_QUALS (ttl) & ~TYPE_QUALS (ttr))
4032                 WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4033                                         "qualified function pointer "
4034                                         "from unqualified"),
4035                                      G_("assignment makes qualified function "
4036                                         "pointer from unqualified"),
4037                                      G_("initialization makes qualified "
4038                                         "function pointer from unqualified"),
4039                                      G_("return makes qualified function "
4040                                         "pointer from unqualified"));
4041             }
4042         }
4043       else
4044         /* Avoid warning about the volatile ObjC EH puts on decls.  */
4045         if (!objc_ok)
4046           WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE from "
4047                                   "incompatible pointer type"),
4048                                G_("assignment from incompatible pointer type"),
4049                                G_("initialization from incompatible "
4050                                   "pointer type"),
4051                                G_("return from incompatible pointer type"));
4052
4053       return convert (type, rhs);
4054     }
4055   else if (codel == POINTER_TYPE && coder == ARRAY_TYPE)
4056     {
4057       /* ??? This should not be an error when inlining calls to
4058          unprototyped functions.  */
4059       error ("invalid use of non-lvalue array");
4060       return error_mark_node;
4061     }
4062   else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
4063     {
4064       /* An explicit constant 0 can convert to a pointer,
4065          or one that results from arithmetic, even including
4066          a cast to integer type.  */
4067       if (!(TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
4068           &&
4069           !(TREE_CODE (rhs) == NOP_EXPR
4070             && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
4071             && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
4072             && integer_zerop (TREE_OPERAND (rhs, 0))))
4073         WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
4074                                 "pointer from integer without a cast"),
4075                              G_("assignment makes pointer from integer "
4076                                 "without a cast"),
4077                              G_("initialization makes pointer from "
4078                                 "integer without a cast"),
4079                              G_("return makes pointer from integer "
4080                                 "without a cast"));
4081
4082       return convert (type, rhs);
4083     }
4084   else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
4085     {
4086       WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes integer "
4087                               "from pointer without a cast"),
4088                            G_("assignment makes integer from pointer "
4089                               "without a cast"),
4090                            G_("initialization makes integer from pointer "
4091                               "without a cast"),
4092                            G_("return makes integer from pointer "
4093                               "without a cast"));
4094       return convert (type, rhs);
4095     }
4096   else if (codel == BOOLEAN_TYPE && coder == POINTER_TYPE)
4097     return convert (type, rhs);
4098
4099   switch (errtype)
4100     {
4101     case ic_argpass:
4102     case ic_argpass_nonproto:
4103       /* ??? This should not be an error when inlining calls to
4104          unprototyped functions.  */
4105       error ("incompatible type for argument %d of %qE", parmnum, rname);
4106       break;
4107     case ic_assign:
4108       error ("incompatible types in assignment");
4109       break;
4110     case ic_init:
4111       error ("incompatible types in initialization");
4112       break;
4113     case ic_return:
4114       error ("incompatible types in return");
4115       break;
4116     default:
4117       gcc_unreachable ();
4118     }
4119
4120   return error_mark_node;
4121 }
4122
4123 /* Convert VALUE for assignment into inlined parameter PARM.  ARGNUM
4124    is used for error and waring reporting and indicates which argument
4125    is being processed.  */
4126
4127 tree
4128 c_convert_parm_for_inlining (tree parm, tree value, tree fn, int argnum)
4129 {
4130   tree ret, type;
4131
4132   /* If FN was prototyped, the value has been converted already
4133      in convert_arguments.  */
4134   if (!value || TYPE_ARG_TYPES (TREE_TYPE (fn)))
4135     return value;
4136
4137   type = TREE_TYPE (parm);
4138   ret = convert_for_assignment (type, value,
4139                                 ic_argpass_nonproto, fn,
4140                                 fn, argnum);
4141   if (targetm.calls.promote_prototypes (TREE_TYPE (fn))
4142       && INTEGRAL_TYPE_P (type)
4143       && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
4144     ret = default_conversion (ret);
4145   return ret;
4146 }
4147 \f
4148 /* If VALUE is a compound expr all of whose expressions are constant, then
4149    return its value.  Otherwise, return error_mark_node.
4150
4151    This is for handling COMPOUND_EXPRs as initializer elements
4152    which is allowed with a warning when -pedantic is specified.  */
4153
4154 static tree
4155 valid_compound_expr_initializer (tree value, tree endtype)
4156 {
4157   if (TREE_CODE (value) == COMPOUND_EXPR)
4158     {
4159       if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
4160           == error_mark_node)
4161         return error_mark_node;
4162       return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
4163                                               endtype);
4164     }
4165   else if (!initializer_constant_valid_p (value, endtype))
4166     return error_mark_node;
4167   else
4168     return value;
4169 }
4170 \f
4171 /* Perform appropriate conversions on the initial value of a variable,
4172    store it in the declaration DECL,
4173    and print any error messages that are appropriate.
4174    If the init is invalid, store an ERROR_MARK.  */
4175
4176 void
4177 store_init_value (tree decl, tree init)
4178 {
4179   tree value, type;
4180
4181   /* If variable's type was invalidly declared, just ignore it.  */
4182
4183   type = TREE_TYPE (decl);
4184   if (TREE_CODE (type) == ERROR_MARK)
4185     return;
4186
4187   /* Digest the specified initializer into an expression.  */
4188
4189   value = digest_init (type, init, true, TREE_STATIC (decl));
4190
4191   /* Store the expression if valid; else report error.  */
4192
4193   if (!in_system_header
4194       && AGGREGATE_TYPE_P (TREE_TYPE (decl)) && !TREE_STATIC (decl))
4195     warning (OPT_Wtraditional, "traditional C rejects automatic "
4196              "aggregate initialization");
4197
4198   DECL_INITIAL (decl) = value;
4199
4200   /* ANSI wants warnings about out-of-range constant initializers.  */
4201   STRIP_TYPE_NOPS (value);
4202   constant_expression_warning (value);
4203
4204   /* Check if we need to set array size from compound literal size.  */
4205   if (TREE_CODE (type) == ARRAY_TYPE
4206       && TYPE_DOMAIN (type) == 0
4207       && value != error_mark_node)
4208     {
4209       tree inside_init = init;
4210
4211       STRIP_TYPE_NOPS (inside_init);
4212       inside_init = fold (inside_init);
4213
4214       if (TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4215         {
4216           tree cldecl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4217
4218           if (TYPE_DOMAIN (TREE_TYPE (cldecl)))
4219             {
4220               /* For int foo[] = (int [3]){1}; we need to set array size
4221                  now since later on array initializer will be just the
4222                  brace enclosed list of the compound literal.  */
4223               type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
4224               TREE_TYPE (decl) = type;
4225               TYPE_DOMAIN (type) = TYPE_DOMAIN (TREE_TYPE (cldecl));
4226               layout_type (type);
4227               layout_decl (cldecl, 0);
4228             }
4229         }
4230     }
4231 }
4232 \f
4233 /* Methods for storing and printing names for error messages.  */
4234
4235 /* Implement a spelling stack that allows components of a name to be pushed
4236    and popped.  Each element on the stack is this structure.  */
4237
4238 struct spelling
4239 {
4240   int kind;
4241   union
4242     {
4243       unsigned HOST_WIDE_INT i;
4244       const char *s;
4245     } u;
4246 };
4247
4248 #define SPELLING_STRING 1
4249 #define SPELLING_MEMBER 2
4250 #define SPELLING_BOUNDS 3
4251
4252 static struct spelling *spelling;       /* Next stack element (unused).  */
4253 static struct spelling *spelling_base;  /* Spelling stack base.  */
4254 static int spelling_size;               /* Size of the spelling stack.  */
4255
4256 /* Macros to save and restore the spelling stack around push_... functions.
4257    Alternative to SAVE_SPELLING_STACK.  */
4258
4259 #define SPELLING_DEPTH() (spelling - spelling_base)
4260 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4261
4262 /* Push an element on the spelling stack with type KIND and assign VALUE
4263    to MEMBER.  */
4264
4265 #define PUSH_SPELLING(KIND, VALUE, MEMBER)                              \
4266 {                                                                       \
4267   int depth = SPELLING_DEPTH ();                                        \
4268                                                                         \
4269   if (depth >= spelling_size)                                           \
4270     {                                                                   \
4271       spelling_size += 10;                                              \
4272       spelling_base = XRESIZEVEC (struct spelling, spelling_base,       \
4273                                   spelling_size);                       \
4274       RESTORE_SPELLING_DEPTH (depth);                                   \
4275     }                                                                   \
4276                                                                         \
4277   spelling->kind = (KIND);                                              \
4278   spelling->MEMBER = (VALUE);                                           \
4279   spelling++;                                                           \
4280 }
4281
4282 /* Push STRING on the stack.  Printed literally.  */
4283
4284 static void
4285 push_string (const char *string)
4286 {
4287   PUSH_SPELLING (SPELLING_STRING, string, u.s);
4288 }
4289
4290 /* Push a member name on the stack.  Printed as '.' STRING.  */
4291
4292 static void
4293 push_member_name (tree decl)
4294 {
4295   const char *const string
4296     = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
4297   PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
4298 }
4299
4300 /* Push an array bounds on the stack.  Printed as [BOUNDS].  */
4301
4302 static void
4303 push_array_bounds (unsigned HOST_WIDE_INT bounds)
4304 {
4305   PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
4306 }
4307
4308 /* Compute the maximum size in bytes of the printed spelling.  */
4309
4310 static int
4311 spelling_length (void)
4312 {
4313   int size = 0;
4314   struct spelling *p;
4315
4316   for (p = spelling_base; p < spelling; p++)
4317     {
4318       if (p->kind == SPELLING_BOUNDS)
4319         size += 25;
4320       else
4321         size += strlen (p->u.s) + 1;
4322     }
4323
4324   return size;
4325 }
4326
4327 /* Print the spelling to BUFFER and return it.  */
4328
4329 static char *
4330 print_spelling (char *buffer)
4331 {
4332   char *d = buffer;
4333   struct spelling *p;
4334
4335   for (p = spelling_base; p < spelling; p++)
4336     if (p->kind == SPELLING_BOUNDS)
4337       {
4338         sprintf (d, "[" HOST_WIDE_INT_PRINT_UNSIGNED "]", p->u.i);
4339         d += strlen (d);
4340       }
4341     else
4342       {
4343         const char *s;
4344         if (p->kind == SPELLING_MEMBER)
4345           *d++ = '.';
4346         for (s = p->u.s; (*d = *s++); d++)
4347           ;
4348       }
4349   *d++ = '\0';
4350   return buffer;
4351 }
4352
4353 /* Issue an error message for a bad initializer component.
4354    MSGID identifies the message.
4355    The component name is taken from the spelling stack.  */
4356
4357 void
4358 error_init (const char *msgid)
4359 {
4360   char *ofwhat;
4361
4362   error ("%s", _(msgid));
4363   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4364   if (*ofwhat)
4365     error ("(near initialization for %qs)", ofwhat);
4366 }
4367
4368 /* Issue a pedantic warning for a bad initializer component.
4369    MSGID identifies the message.
4370    The component name is taken from the spelling stack.  */
4371
4372 void
4373 pedwarn_init (const char *msgid)
4374 {
4375   char *ofwhat;
4376
4377   pedwarn ("%s", _(msgid));
4378   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4379   if (*ofwhat)
4380     pedwarn ("(near initialization for %qs)", ofwhat);
4381 }
4382
4383 /* Issue a warning for a bad initializer component.
4384    MSGID identifies the message.
4385    The component name is taken from the spelling stack.  */
4386
4387 static void
4388 warning_init (const char *msgid)
4389 {
4390   char *ofwhat;
4391
4392   warning (0, "%s", _(msgid));
4393   ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
4394   if (*ofwhat)
4395     warning (0, "(near initialization for %qs)", ofwhat);
4396 }
4397 \f
4398 /* If TYPE is an array type and EXPR is a parenthesized string
4399    constant, warn if pedantic that EXPR is being used to initialize an
4400    object of type TYPE.  */
4401
4402 void
4403 maybe_warn_string_init (tree type, struct c_expr expr)
4404 {
4405   if (pedantic
4406       && TREE_CODE (type) == ARRAY_TYPE
4407       && TREE_CODE (expr.value) == STRING_CST
4408       && expr.original_code != STRING_CST)
4409     pedwarn_init ("array initialized from parenthesized string constant");
4410 }
4411
4412 /* Digest the parser output INIT as an initializer for type TYPE.
4413    Return a C expression of type TYPE to represent the initial value.
4414
4415    If INIT is a string constant, STRICT_STRING is true if it is
4416    unparenthesized or we should not warn here for it being parenthesized.
4417    For other types of INIT, STRICT_STRING is not used.
4418
4419    REQUIRE_CONSTANT requests an error if non-constant initializers or
4420    elements are seen.  */
4421
4422 static tree
4423 digest_init (tree type, tree init, bool strict_string, int require_constant)
4424 {
4425   enum tree_code code = TREE_CODE (type);
4426   tree inside_init = init;
4427
4428   if (type == error_mark_node
4429       || !init
4430       || init == error_mark_node
4431       || TREE_TYPE (init) == error_mark_node)
4432     return error_mark_node;
4433
4434   STRIP_TYPE_NOPS (inside_init);
4435
4436   inside_init = fold (inside_init);
4437
4438   /* Initialization of an array of chars from a string constant
4439      optionally enclosed in braces.  */
4440
4441   if (code == ARRAY_TYPE && inside_init
4442       && TREE_CODE (inside_init) == STRING_CST)
4443     {
4444       tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
4445       /* Note that an array could be both an array of character type
4446          and an array of wchar_t if wchar_t is signed char or unsigned
4447          char.  */
4448       bool char_array = (typ1 == char_type_node
4449                          || typ1 == signed_char_type_node
4450                          || typ1 == unsigned_char_type_node);
4451       bool wchar_array = !!comptypes (typ1, wchar_type_node);
4452       if (char_array || wchar_array)
4453         {
4454           struct c_expr expr;
4455           bool char_string;
4456           expr.value = inside_init;
4457           expr.original_code = (strict_string ? STRING_CST : ERROR_MARK);
4458           maybe_warn_string_init (type, expr);
4459
4460           char_string
4461             = (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
4462                == char_type_node);
4463
4464           if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4465                          TYPE_MAIN_VARIANT (type)))
4466             return inside_init;
4467
4468           if (!wchar_array && !char_string)
4469             {
4470               error_init ("char-array initialized from wide string");
4471               return error_mark_node;
4472             }
4473           if (char_string && !char_array)
4474             {
4475               error_init ("wchar_t-array initialized from non-wide string");
4476               return error_mark_node;
4477             }
4478
4479           TREE_TYPE (inside_init) = type;
4480           if (TYPE_DOMAIN (type) != 0
4481               && TYPE_SIZE (type) != 0
4482               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
4483               /* Subtract 1 (or sizeof (wchar_t))
4484                  because it's ok to ignore the terminating null char
4485                  that is counted in the length of the constant.  */
4486               && 0 > compare_tree_int (TYPE_SIZE_UNIT (type),
4487                                        TREE_STRING_LENGTH (inside_init)
4488                                        - ((TYPE_PRECISION (typ1)
4489                                            != TYPE_PRECISION (char_type_node))
4490                                           ? (TYPE_PRECISION (wchar_type_node)
4491                                              / BITS_PER_UNIT)
4492                                           : 1)))
4493             pedwarn_init ("initializer-string for array of chars is too long");
4494
4495           return inside_init;
4496         }
4497       else if (INTEGRAL_TYPE_P (typ1))
4498         {
4499           error_init ("array of inappropriate type initialized "
4500                       "from string constant");
4501           return error_mark_node;
4502         }
4503     }
4504
4505   /* Build a VECTOR_CST from a *constant* vector constructor.  If the
4506      vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4507      below and handle as a constructor.  */
4508   if (code == VECTOR_TYPE
4509       && TREE_CODE (TREE_TYPE (inside_init)) == VECTOR_TYPE
4510       && vector_types_convertible_p (TREE_TYPE (inside_init), type)
4511       && TREE_CONSTANT (inside_init))
4512     {
4513       if (TREE_CODE (inside_init) == VECTOR_CST
4514           && comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4515                         TYPE_MAIN_VARIANT (type)))
4516         return inside_init;
4517
4518       if (TREE_CODE (inside_init) == CONSTRUCTOR)
4519         {
4520           unsigned HOST_WIDE_INT ix;
4521           tree value;
4522           bool constant_p = true;
4523
4524           /* Iterate through elements and check if all constructor
4525              elements are *_CSTs.  */
4526           FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (inside_init), ix, value)
4527             if (!CONSTANT_CLASS_P (value))
4528               {
4529                 constant_p = false;
4530                 break;
4531               }
4532
4533           if (constant_p)
4534             return build_vector_from_ctor (type,
4535                                            CONSTRUCTOR_ELTS (inside_init));
4536         }
4537     }
4538
4539   /* Any type can be initialized
4540      from an expression of the same type, optionally with braces.  */
4541
4542   if (inside_init && TREE_TYPE (inside_init) != 0
4543       && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
4544                      TYPE_MAIN_VARIANT (type))
4545           || (code == ARRAY_TYPE
4546               && comptypes (TREE_TYPE (inside_init), type))
4547           || (code == VECTOR_TYPE
4548               && comptypes (TREE_TYPE (inside_init), type))
4549           || (code == POINTER_TYPE
4550               && TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
4551               && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
4552                             TREE_TYPE (type)))))
4553     {
4554       if (code == POINTER_TYPE)
4555         {
4556           if (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE)
4557             {
4558               if (TREE_CODE (inside_init) == STRING_CST
4559                   || TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4560                 inside_init = array_to_pointer_conversion (inside_init);
4561               else
4562                 {
4563                   error_init ("invalid use of non-lvalue array");
4564                   return error_mark_node;
4565                 }
4566             }
4567         }
4568
4569       if (code == VECTOR_TYPE)
4570         /* Although the types are compatible, we may require a
4571            conversion.  */
4572         inside_init = convert (type, inside_init);
4573
4574       if (require_constant
4575           && (code == VECTOR_TYPE || !flag_isoc99)
4576           && TREE_CODE (inside_init) == COMPOUND_LITERAL_EXPR)
4577         {
4578           /* As an extension, allow initializing objects with static storage
4579              duration with compound literals (which are then treated just as
4580              the brace enclosed list they contain).  Also allow this for
4581              vectors, as we can only assign them with compound literals.  */
4582           tree decl = COMPOUND_LITERAL_EXPR_DECL (inside_init);
4583           inside_init = DECL_INITIAL (decl);
4584         }
4585
4586       if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
4587           && TREE_CODE (inside_init) != CONSTRUCTOR)
4588         {
4589           error_init ("array initialized from non-constant array expression");
4590           return error_mark_node;
4591         }
4592
4593       if (optimize && TREE_CODE (inside_init) == VAR_DECL)
4594         inside_init = decl_constant_value_for_broken_optimization (inside_init);
4595
4596       /* Compound expressions can only occur here if -pedantic or
4597          -pedantic-errors is specified.  In the later case, we always want
4598          an error.  In the former case, we simply want a warning.  */
4599       if (require_constant && pedantic
4600           && TREE_CODE (inside_init) == COMPOUND_EXPR)
4601         {
4602           inside_init
4603             = valid_compound_expr_initializer (inside_init,
4604                                                TREE_TYPE (inside_init));
4605           if (inside_init == error_mark_node)
4606             error_init ("initializer element is not constant");
4607           else
4608             pedwarn_init ("initializer element is not constant");
4609           if (flag_pedantic_errors)
4610             inside_init = error_mark_node;
4611         }
4612       else if (require_constant
4613                && !initializer_constant_valid_p (inside_init,
4614                                                  TREE_TYPE (inside_init)))
4615         {
4616           error_init ("initializer element is not constant");
4617           inside_init = error_mark_node;
4618         }
4619
4620       /* Added to enable additional -Wmissing-format-attribute warnings.  */
4621       if (TREE_CODE (TREE_TYPE (inside_init)) == POINTER_TYPE)
4622         inside_init = convert_for_assignment (type, inside_init, ic_init, NULL_TREE,
4623                                               NULL_TREE, 0);
4624       return inside_init;
4625     }
4626
4627   /* Handle scalar types, including conversions.  */
4628
4629   if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
4630       || code == ENUMERAL_TYPE || code == BOOLEAN_TYPE || code == COMPLEX_TYPE
4631       || code == VECTOR_TYPE)
4632     {
4633       if (TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE
4634           && (TREE_CODE (init) == STRING_CST
4635               || TREE_CODE (init) == COMPOUND_LITERAL_EXPR))
4636         init = array_to_pointer_conversion (init);
4637       inside_init
4638         = convert_for_assignment (type, init, ic_init,
4639                                   NULL_TREE, NULL_TREE, 0);
4640
4641       /* Check to see if we have already given an error message.  */
4642       if (inside_init == error_mark_node)
4643         ;
4644       else if (require_constant && !TREE_CONSTANT (inside_init))
4645         {
4646           error_init ("initializer element is not constant");
4647           inside_init = error_mark_node;
4648         }
4649       else if (require_constant
4650                && !initializer_constant_valid_p (inside_init,
4651                                                  TREE_TYPE (inside_init)))
4652         {
4653           error_init ("initializer element is not computable at load time");
4654           inside_init = error_mark_node;
4655         }
4656
4657       return inside_init;
4658     }
4659
4660   /* Come here only for records and arrays.  */
4661
4662   if (COMPLETE_TYPE_P (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
4663     {
4664       error_init ("variable-sized object may not be initialized");
4665       return error_mark_node;
4666     }
4667
4668   error_init ("invalid initializer");
4669   return error_mark_node;
4670 }
4671 \f
4672 /* Handle initializers that use braces.  */
4673
4674 /* Type of object we are accumulating a constructor for.
4675    This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
4676 static tree constructor_type;
4677
4678 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4679    left to fill.  */
4680 static tree constructor_fields;
4681
4682 /* For an ARRAY_TYPE, this is the specified index
4683    at which to store the next element we get.  */
4684 static tree constructor_index;
4685
4686 /* For an ARRAY_TYPE, this is the maximum index.  */
4687 static tree constructor_max_index;
4688
4689 /* For a RECORD_TYPE, this is the first field not yet written out.  */
4690 static tree constructor_unfilled_fields;
4691
4692 /* For an ARRAY_TYPE, this is the index of the first element
4693    not yet written out.  */
4694 static tree constructor_unfilled_index;
4695
4696 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4697    This is so we can generate gaps between fields, when appropriate.  */
4698 static tree constructor_bit_index;
4699
4700 /* If we are saving up the elements rather than allocating them,
4701    this is the list of elements so far (in reverse order,
4702    most recent first).  */
4703 static VEC(constructor_elt,gc) *constructor_elements;
4704
4705 /* 1 if constructor should be incrementally stored into a constructor chain,
4706    0 if all the elements should be kept in AVL tree.  */
4707 static int constructor_incremental;
4708
4709 /* 1 if so far this constructor's elements are all compile-time constants.  */
4710 static int constructor_constant;
4711
4712 /* 1 if so far this constructor's elements are all valid address constants.  */
4713 static int constructor_simple;
4714
4715 /* 1 if this constructor is erroneous so far.  */
4716 static int constructor_erroneous;
4717
4718 /* Structure for managing pending initializer elements, organized as an
4719    AVL tree.  */
4720
4721 struct init_node
4722 {
4723   struct init_node *left, *right;
4724   struct init_node *parent;
4725   int balance;
4726   tree purpose;
4727   tree value;
4728 };
4729
4730 /* Tree of pending elements at this constructor level.
4731    These are elements encountered out of order
4732    which belong at places we haven't reached yet in actually
4733    writing the output.
4734    Will never hold tree nodes across GC runs.  */
4735 static struct init_node *constructor_pending_elts;
4736
4737 /* The SPELLING_DEPTH of this constructor.  */
4738 static int constructor_depth;
4739
4740 /* DECL node for which an initializer is being read.
4741    0 means we are reading a constructor expression
4742    such as (struct foo) {...}.  */
4743 static tree constructor_decl;
4744
4745 /* Nonzero if this is an initializer for a top-level decl.  */
4746 static int constructor_top_level;
4747
4748 /* Nonzero if there were any member designators in this initializer.  */
4749 static int constructor_designated;
4750
4751 /* Nesting depth of designator list.  */
4752 static int designator_depth;
4753
4754 /* Nonzero if there were diagnosed errors in this designator list.  */
4755 static int designator_erroneous;
4756
4757 \f
4758 /* This stack has a level for each implicit or explicit level of
4759    structuring in the initializer, including the outermost one.  It
4760    saves the values of most of the variables above.  */
4761
4762 struct constructor_range_stack;
4763
4764 struct constructor_stack
4765 {
4766   struct constructor_stack *next;
4767   tree type;
4768   tree fields;
4769   tree index;
4770   tree max_index;
4771   tree unfilled_index;
4772   tree unfilled_fields;
4773   tree bit_index;
4774   VEC(constructor_elt,gc) *elements;
4775   struct init_node *pending_elts;
4776   int offset;
4777   int depth;
4778   /* If value nonzero, this value should replace the entire
4779      constructor at this level.  */
4780   struct c_expr replacement_value;
4781   struct constructor_range_stack *range_stack;
4782   char constant;
4783   char simple;
4784   char implicit;
4785   char erroneous;
4786   char outer;
4787   char incremental;
4788   char designated;
4789 };
4790
4791 static struct constructor_stack *constructor_stack;
4792
4793 /* This stack represents designators from some range designator up to
4794    the last designator in the list.  */
4795
4796 struct constructor_range_stack
4797 {
4798   struct constructor_range_stack *next, *prev;
4799   struct constructor_stack *stack;
4800   tree range_start;
4801   tree index;
4802   tree range_end;
4803   tree fields;
4804 };
4805
4806 static struct constructor_range_stack *constructor_range_stack;
4807
4808 /* This stack records separate initializers that are nested.
4809    Nested initializers can't happen in ANSI C, but GNU C allows them
4810    in cases like { ... (struct foo) { ... } ... }.  */
4811
4812 struct initializer_stack
4813 {
4814   struct initializer_stack *next;
4815   tree decl;
4816   struct constructor_stack *constructor_stack;
4817   struct constructor_range_stack *constructor_range_stack;
4818   VEC(constructor_elt,gc) *elements;
4819   struct spelling *spelling;
4820   struct spelling *spelling_base;
4821   int spelling_size;
4822   char top_level;
4823   char require_constant_value;
4824   char require_constant_elements;
4825 };
4826
4827 static struct initializer_stack *initializer_stack;
4828 \f
4829 /* Prepare to parse and output the initializer for variable DECL.  */
4830
4831 void
4832 start_init (tree decl, tree asmspec_tree ATTRIBUTE_UNUSED, int top_level)
4833 {
4834   const char *locus;
4835   struct initializer_stack *p = xmalloc (sizeof (struct initializer_stack));
4836
4837   p->decl = constructor_decl;
4838   p->require_constant_value = require_constant_value;
4839   p->require_constant_elements = require_constant_elements;
4840   p->constructor_stack = constructor_stack;
4841   p->constructor_range_stack = constructor_range_stack;
4842   p->elements = constructor_elements;
4843   p->spelling = spelling;
4844   p->spelling_base = spelling_base;
4845   p->spelling_size = spelling_size;
4846   p->top_level = constructor_top_level;
4847   p->next = initializer_stack;
4848   initializer_stack = p;
4849
4850   constructor_decl = decl;
4851   constructor_designated = 0;
4852   constructor_top_level = top_level;
4853
4854   if (decl != 0 && decl != error_mark_node)
4855     {
4856       require_constant_value = TREE_STATIC (decl);
4857       require_constant_elements
4858         = ((TREE_STATIC (decl) || (pedantic && !flag_isoc99))
4859            /* For a scalar, you can always use any value to initialize,
4860               even within braces.  */
4861            && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
4862                || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
4863                || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
4864                || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
4865       locus = IDENTIFIER_POINTER (DECL_NAME (decl));
4866     }
4867   else
4868     {
4869       require_constant_value = 0;
4870       require_constant_elements = 0;
4871       locus = "(anonymous)";
4872     }
4873
4874   constructor_stack = 0;
4875   constructor_range_stack = 0;
4876
4877   missing_braces_mentioned = 0;
4878
4879   spelling_base = 0;
4880   spelling_size = 0;
4881   RESTORE_SPELLING_DEPTH (0);
4882
4883   if (locus)
4884     push_string (locus);
4885 }
4886
4887 void
4888 finish_init (void)
4889 {
4890   struct initializer_stack *p = initializer_stack;
4891
4892   /* Free the whole constructor stack of this initializer.  */
4893   while (constructor_stack)
4894     {
4895       struct constructor_stack *q = constructor_stack;
4896       constructor_stack = q->next;
4897       free (q);
4898     }
4899
4900   gcc_assert (!constructor_range_stack);
4901
4902   /* Pop back to the data of the outer initializer (if any).  */
4903   free (spelling_base);
4904
4905   constructor_decl = p->decl;
4906   require_constant_value = p->require_constant_value;
4907   require_constant_elements = p->require_constant_elements;
4908   constructor_stack = p->constructor_stack;
4909   constructor_range_stack = p->constructor_range_stack;
4910   constructor_elements = p->elements;
4911   spelling = p->spelling;
4912   spelling_base = p->spelling_base;
4913   spelling_size = p->spelling_size;
4914   constructor_top_level = p->top_level;
4915   initializer_stack = p->next;
4916   free (p);
4917 }
4918 \f
4919 /* Call here when we see the initializer is surrounded by braces.
4920    This is instead of a call to push_init_level;
4921    it is matched by a call to pop_init_level.
4922
4923    TYPE is the type to initialize, for a constructor expression.
4924    For an initializer for a decl, TYPE is zero.  */
4925
4926 void
4927 really_start_incremental_init (tree type)
4928 {
4929   struct constructor_stack *p = XNEW (struct constructor_stack);
4930
4931   if (type == 0)
4932     type = TREE_TYPE (constructor_decl);
4933
4934   if (targetm.vector_opaque_p (type))
4935     error ("opaque vector types cannot be initialized");
4936
4937   p->type = constructor_type;
4938   p->fields = constructor_fields;
4939   p->index = constructor_index;
4940   p->max_index = constructor_max_index;
4941   p->unfilled_index = constructor_unfilled_index;
4942   p->unfilled_fields = constructor_unfilled_fields;
4943   p->bit_index = constructor_bit_index;
4944   p->elements = constructor_elements;
4945   p->constant = constructor_constant;
4946   p->simple = constructor_simple;
4947   p->erroneous = constructor_erroneous;
4948   p->pending_elts = constructor_pending_elts;
4949   p->depth = constructor_depth;
4950   p->replacement_value.value = 0;
4951   p->replacement_value.original_code = ERROR_MARK;
4952   p->implicit = 0;
4953   p->range_stack = 0;
4954   p->outer = 0;
4955   p->incremental = constructor_incremental;
4956   p->designated = constructor_designated;
4957   p->next = 0;
4958   constructor_stack = p;
4959
4960   constructor_constant = 1;
4961   constructor_simple = 1;
4962   constructor_depth = SPELLING_DEPTH ();
4963   constructor_elements = 0;
4964   constructor_pending_elts = 0;
4965   constructor_type = type;
4966   constructor_incremental = 1;
4967   constructor_designated = 0;
4968   designator_depth = 0;
4969   designator_erroneous = 0;
4970
4971   if (TREE_CODE (constructor_type) == RECORD_TYPE
4972       || TREE_CODE (constructor_type) == UNION_TYPE)
4973     {
4974       constructor_fields = TYPE_FIELDS (constructor_type);
4975       /* Skip any nameless bit fields at the beginning.  */
4976       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
4977              && DECL_NAME (constructor_fields) == 0)
4978         constructor_fields = TREE_CHAIN (constructor_fields);
4979
4980       constructor_unfilled_fields = constructor_fields;
4981       constructor_bit_index = bitsize_zero_node;
4982     }
4983   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
4984     {
4985       if (TYPE_DOMAIN (constructor_type))
4986         {
4987           constructor_max_index
4988             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
4989
4990           /* Detect non-empty initializations of zero-length arrays.  */
4991           if (constructor_max_index == NULL_TREE
4992               && TYPE_SIZE (constructor_type))
4993             constructor_max_index = build_int_cst (NULL_TREE, -1);
4994
4995           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
4996              to initialize VLAs will cause a proper error; avoid tree
4997              checking errors as well by setting a safe value.  */
4998           if (constructor_max_index
4999               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5000             constructor_max_index = build_int_cst (NULL_TREE, -1);
5001
5002           constructor_index
5003             = convert (bitsizetype,
5004                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5005         }
5006       else
5007         {
5008           constructor_index = bitsize_zero_node;
5009           constructor_max_index = NULL_TREE;
5010         }
5011
5012       constructor_unfilled_index = constructor_index;
5013     }
5014   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5015     {
5016       /* Vectors are like simple fixed-size arrays.  */
5017       constructor_max_index =
5018         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5019       constructor_index = bitsize_zero_node;
5020       constructor_unfilled_index = constructor_index;
5021     }
5022   else
5023     {
5024       /* Handle the case of int x = {5}; */
5025       constructor_fields = constructor_type;
5026       constructor_unfilled_fields = constructor_type;
5027     }
5028 }
5029 \f
5030 /* Push down into a subobject, for initialization.
5031    If this is for an explicit set of braces, IMPLICIT is 0.
5032    If it is because the next element belongs at a lower level,
5033    IMPLICIT is 1 (or 2 if the push is because of designator list).  */
5034
5035 void
5036 push_init_level (int implicit)
5037 {
5038   struct constructor_stack *p;
5039   tree value = NULL_TREE;
5040
5041   /* If we've exhausted any levels that didn't have braces,
5042      pop them now.  If implicit == 1, this will have been done in
5043      process_init_element; do not repeat it here because in the case
5044      of excess initializers for an empty aggregate this leads to an
5045      infinite cycle of popping a level and immediately recreating
5046      it.  */
5047   if (implicit != 1)
5048     {
5049       while (constructor_stack->implicit)
5050         {
5051           if ((TREE_CODE (constructor_type) == RECORD_TYPE
5052                || TREE_CODE (constructor_type) == UNION_TYPE)
5053               && constructor_fields == 0)
5054             process_init_element (pop_init_level (1));
5055           else if (TREE_CODE (constructor_type) == ARRAY_TYPE
5056                    && constructor_max_index
5057                    && tree_int_cst_lt (constructor_max_index,
5058                                        constructor_index))
5059             process_init_element (pop_init_level (1));
5060           else
5061             break;
5062         }
5063     }
5064
5065   /* Unless this is an explicit brace, we need to preserve previous
5066      content if any.  */
5067   if (implicit)
5068     {
5069       if ((TREE_CODE (constructor_type) == RECORD_TYPE
5070            || TREE_CODE (constructor_type) == UNION_TYPE)
5071           && constructor_fields)
5072         value = find_init_member (constructor_fields);
5073       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5074         value = find_init_member (constructor_index);
5075     }
5076
5077   p = XNEW (struct constructor_stack);
5078   p->type = constructor_type;
5079   p->fields = constructor_fields;
5080   p->index = constructor_index;
5081   p->max_index = constructor_max_index;
5082   p->unfilled_index = constructor_unfilled_index;
5083   p->unfilled_fields = constructor_unfilled_fields;
5084   p->bit_index = constructor_bit_index;
5085   p->elements = constructor_elements;
5086   p->constant = constructor_constant;
5087   p->simple = constructor_simple;
5088   p->erroneous = constructor_erroneous;
5089   p->pending_elts = constructor_pending_elts;
5090   p->depth = constructor_depth;
5091   p->replacement_value.value = 0;
5092   p->replacement_value.original_code = ERROR_MARK;
5093   p->implicit = implicit;
5094   p->outer = 0;
5095   p->incremental = constructor_incremental;
5096   p->designated = constructor_designated;
5097   p->next = constructor_stack;
5098   p->range_stack = 0;
5099   constructor_stack = p;
5100
5101   constructor_constant = 1;
5102   constructor_simple = 1;
5103   constructor_depth = SPELLING_DEPTH ();
5104   constructor_elements = 0;
5105   constructor_incremental = 1;
5106   constructor_designated = 0;
5107   constructor_pending_elts = 0;
5108   if (!implicit)
5109     {
5110       p->range_stack = constructor_range_stack;
5111       constructor_range_stack = 0;
5112       designator_depth = 0;
5113       designator_erroneous = 0;
5114     }
5115
5116   /* Don't die if an entire brace-pair level is superfluous
5117      in the containing level.  */
5118   if (constructor_type == 0)
5119     ;
5120   else if (TREE_CODE (constructor_type) == RECORD_TYPE
5121            || TREE_CODE (constructor_type) == UNION_TYPE)
5122     {
5123       /* Don't die if there are extra init elts at the end.  */
5124       if (constructor_fields == 0)
5125         constructor_type = 0;
5126       else
5127         {
5128           constructor_type = TREE_TYPE (constructor_fields);
5129           push_member_name (constructor_fields);
5130           constructor_depth++;
5131         }
5132     }
5133   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5134     {
5135       constructor_type = TREE_TYPE (constructor_type);
5136       push_array_bounds (tree_low_cst (constructor_index, 1));
5137       constructor_depth++;
5138     }
5139
5140   if (constructor_type == 0)
5141     {
5142       error_init ("extra brace group at end of initializer");
5143       constructor_fields = 0;
5144       constructor_unfilled_fields = 0;
5145       return;
5146     }
5147
5148   if (value && TREE_CODE (value) == CONSTRUCTOR)
5149     {
5150       constructor_constant = TREE_CONSTANT (value);
5151       constructor_simple = TREE_STATIC (value);
5152       constructor_elements = CONSTRUCTOR_ELTS (value);
5153       if (!VEC_empty (constructor_elt, constructor_elements)
5154           && (TREE_CODE (constructor_type) == RECORD_TYPE
5155               || TREE_CODE (constructor_type) == ARRAY_TYPE))
5156         set_nonincremental_init ();
5157     }
5158
5159   if (implicit == 1 && warn_missing_braces && !missing_braces_mentioned)
5160     {
5161       missing_braces_mentioned = 1;
5162       warning_init ("missing braces around initializer");
5163     }
5164
5165   if (TREE_CODE (constructor_type) == RECORD_TYPE
5166            || TREE_CODE (constructor_type) == UNION_TYPE)
5167     {
5168       constructor_fields = TYPE_FIELDS (constructor_type);
5169       /* Skip any nameless bit fields at the beginning.  */
5170       while (constructor_fields != 0 && DECL_C_BIT_FIELD (constructor_fields)
5171              && DECL_NAME (constructor_fields) == 0)
5172         constructor_fields = TREE_CHAIN (constructor_fields);
5173
5174       constructor_unfilled_fields = constructor_fields;
5175       constructor_bit_index = bitsize_zero_node;
5176     }
5177   else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
5178     {
5179       /* Vectors are like simple fixed-size arrays.  */
5180       constructor_max_index =
5181         build_int_cst (NULL_TREE, TYPE_VECTOR_SUBPARTS (constructor_type) - 1);
5182       constructor_index = convert (bitsizetype, integer_zero_node);
5183       constructor_unfilled_index = constructor_index;
5184     }
5185   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5186     {
5187       if (TYPE_DOMAIN (constructor_type))
5188         {
5189           constructor_max_index
5190             = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
5191
5192           /* Detect non-empty initializations of zero-length arrays.  */
5193           if (constructor_max_index == NULL_TREE
5194               && TYPE_SIZE (constructor_type))
5195             constructor_max_index = build_int_cst (NULL_TREE, -1);
5196
5197           /* constructor_max_index needs to be an INTEGER_CST.  Attempts
5198              to initialize VLAs will cause a proper error; avoid tree
5199              checking errors as well by setting a safe value.  */
5200           if (constructor_max_index
5201               && TREE_CODE (constructor_max_index) != INTEGER_CST)
5202             constructor_max_index = build_int_cst (NULL_TREE, -1);
5203
5204           constructor_index
5205             = convert (bitsizetype,
5206                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5207         }
5208       else
5209         constructor_index = bitsize_zero_node;
5210
5211       constructor_unfilled_index = constructor_index;
5212       if (value && TREE_CODE (value) == STRING_CST)
5213         {
5214           /* We need to split the char/wchar array into individual
5215              characters, so that we don't have to special case it
5216              everywhere.  */
5217           set_nonincremental_init_from_string (value);
5218         }
5219     }
5220   else
5221     {
5222       if (constructor_type != error_mark_node)
5223         warning_init ("braces around scalar initializer");
5224       constructor_fields = constructor_type;
5225       constructor_unfilled_fields = constructor_type;
5226     }
5227 }
5228
5229 /* At the end of an implicit or explicit brace level,
5230    finish up that level of constructor.  If a single expression
5231    with redundant braces initialized that level, return the
5232    c_expr structure for that expression.  Otherwise, the original_code
5233    element is set to ERROR_MARK.
5234    If we were outputting the elements as they are read, return 0 as the value
5235    from inner levels (process_init_element ignores that),
5236    but return error_mark_node as the value from the outermost level
5237    (that's what we want to put in DECL_INITIAL).
5238    Otherwise, return a CONSTRUCTOR expression as the value.  */
5239
5240 struct c_expr
5241 pop_init_level (int implicit)
5242 {
5243   struct constructor_stack *p;
5244   struct c_expr ret;
5245   ret.value = 0;
5246   ret.original_code = ERROR_MARK;
5247
5248   if (implicit == 0)
5249     {
5250       /* When we come to an explicit close brace,
5251          pop any inner levels that didn't have explicit braces.  */
5252       while (constructor_stack->implicit)
5253         process_init_element (pop_init_level (1));
5254
5255       gcc_assert (!constructor_range_stack);
5256     }
5257
5258   /* Now output all pending elements.  */
5259   constructor_incremental = 1;
5260   output_pending_init_elements (1);
5261
5262   p = constructor_stack;
5263
5264   /* Error for initializing a flexible array member, or a zero-length
5265      array member in an inappropriate context.  */
5266   if (constructor_type && constructor_fields
5267       && TREE_CODE (constructor_type) == ARRAY_TYPE
5268       && TYPE_DOMAIN (constructor_type)
5269       && !TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
5270     {
5271       /* Silently discard empty initializations.  The parser will
5272          already have pedwarned for empty brackets.  */
5273       if (integer_zerop (constructor_unfilled_index))
5274         constructor_type = NULL_TREE;
5275       else
5276         {
5277           gcc_assert (!TYPE_SIZE (constructor_type));
5278
5279           if (constructor_depth > 2)
5280             error_init ("initialization of flexible array member in a nested context");
5281           else if (pedantic)
5282             pedwarn_init ("initialization of a flexible array member");
5283
5284           /* We have already issued an error message for the existence
5285              of a flexible array member not at the end of the structure.
5286              Discard the initializer so that we do not die later.  */
5287           if (TREE_CHAIN (constructor_fields) != NULL_TREE)
5288             constructor_type = NULL_TREE;
5289         }
5290     }
5291
5292   /* Warn when some struct elements are implicitly initialized to zero.  */
5293   if (warn_missing_field_initializers
5294       && constructor_type
5295       && TREE_CODE (constructor_type) == RECORD_TYPE
5296       && constructor_unfilled_fields)
5297     {
5298         /* Do not warn for flexible array members or zero-length arrays.  */
5299         while (constructor_unfilled_fields
5300                && (!DECL_SIZE (constructor_unfilled_fields)
5301                    || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
5302           constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5303
5304         /* Do not warn if this level of the initializer uses member
5305            designators; it is likely to be deliberate.  */
5306         if (constructor_unfilled_fields && !constructor_designated)
5307           {
5308             push_member_name (constructor_unfilled_fields);
5309             warning_init ("missing initializer");
5310             RESTORE_SPELLING_DEPTH (constructor_depth);
5311           }
5312     }
5313
5314   /* Pad out the end of the structure.  */
5315   if (p->replacement_value.value)
5316     /* If this closes a superfluous brace pair,
5317        just pass out the element between them.  */
5318     ret = p->replacement_value;
5319   else if (constructor_type == 0)
5320     ;
5321   else if (TREE_CODE (constructor_type) != RECORD_TYPE
5322            && TREE_CODE (constructor_type) != UNION_TYPE
5323            && TREE_CODE (constructor_type) != ARRAY_TYPE
5324            && TREE_CODE (constructor_type) != VECTOR_TYPE)
5325     {
5326       /* A nonincremental scalar initializer--just return
5327          the element, after verifying there is just one.  */
5328       if (VEC_empty (constructor_elt,constructor_elements))
5329         {
5330           if (!constructor_erroneous)
5331             error_init ("empty scalar initializer");
5332           ret.value = error_mark_node;
5333         }
5334       else if (VEC_length (constructor_elt,constructor_elements) != 1)
5335         {
5336           error_init ("extra elements in scalar initializer");
5337           ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5338         }
5339       else
5340         ret.value = VEC_index (constructor_elt,constructor_elements,0)->value;
5341     }
5342   else
5343     {
5344       if (constructor_erroneous)
5345         ret.value = error_mark_node;
5346       else
5347         {
5348           ret.value = build_constructor (constructor_type,
5349                                          constructor_elements);
5350           if (constructor_constant)
5351             TREE_CONSTANT (ret.value) = TREE_INVARIANT (ret.value) = 1;
5352           if (constructor_constant && constructor_simple)
5353             TREE_STATIC (ret.value) = 1;
5354         }
5355     }
5356
5357   constructor_type = p->type;
5358   constructor_fields = p->fields;
5359   constructor_index = p->index;
5360   constructor_max_index = p->max_index;
5361   constructor_unfilled_index = p->unfilled_index;
5362   constructor_unfilled_fields = p->unfilled_fields;
5363   constructor_bit_index = p->bit_index;
5364   constructor_elements = p->elements;
5365   constructor_constant = p->constant;
5366   constructor_simple = p->simple;
5367   constructor_erroneous = p->erroneous;
5368   constructor_incremental = p->incremental;
5369   constructor_designated = p->designated;
5370   constructor_pending_elts = p->pending_elts;
5371   constructor_depth = p->depth;
5372   if (!p->implicit)
5373     constructor_range_stack = p->range_stack;
5374   RESTORE_SPELLING_DEPTH (constructor_depth);
5375
5376   constructor_stack = p->next;
5377   free (p);
5378
5379   if (ret.value == 0)
5380     {
5381       if (constructor_stack == 0)
5382         {
5383           ret.value = error_mark_node;
5384           return ret;
5385         }
5386       return ret;
5387     }
5388   return ret;
5389 }
5390
5391 /* Common handling for both array range and field name designators.
5392    ARRAY argument is nonzero for array ranges.  Returns zero for success.  */
5393
5394 static int
5395 set_designator (int array)
5396 {
5397   tree subtype;
5398   enum tree_code subcode;
5399
5400   /* Don't die if an entire brace-pair level is superfluous
5401      in the containing level.  */
5402   if (constructor_type == 0)
5403     return 1;
5404
5405   /* If there were errors in this designator list already, bail out
5406      silently.  */
5407   if (designator_erroneous)
5408     return 1;
5409
5410   if (!designator_depth)
5411     {
5412       gcc_assert (!constructor_range_stack);
5413
5414       /* Designator list starts at the level of closest explicit
5415          braces.  */
5416       while (constructor_stack->implicit)
5417         process_init_element (pop_init_level (1));
5418       constructor_designated = 1;
5419       return 0;
5420     }
5421
5422   switch (TREE_CODE (constructor_type))
5423     {
5424     case  RECORD_TYPE:
5425     case  UNION_TYPE:
5426       subtype = TREE_TYPE (constructor_fields);
5427       if (subtype != error_mark_node)
5428         subtype = TYPE_MAIN_VARIANT (subtype);
5429       break;
5430     case ARRAY_TYPE:
5431       subtype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
5432       break;
5433     default:
5434       gcc_unreachable ();
5435     }
5436
5437   subcode = TREE_CODE (subtype);
5438   if (array && subcode != ARRAY_TYPE)
5439     {
5440       error_init ("array index in non-array initializer");
5441       return 1;
5442     }
5443   else if (!array && subcode != RECORD_TYPE && subcode != UNION_TYPE)
5444     {
5445       error_init ("field name not in record or union initializer");
5446       return 1;
5447     }
5448
5449   constructor_designated = 1;
5450   push_init_level (2);
5451   return 0;
5452 }
5453
5454 /* If there are range designators in designator list, push a new designator
5455    to constructor_range_stack.  RANGE_END is end of such stack range or
5456    NULL_TREE if there is no range designator at this level.  */
5457
5458 static void
5459 push_range_stack (tree range_end)
5460 {
5461   struct constructor_range_stack *p;
5462
5463   p = GGC_NEW (struct constructor_range_stack);
5464   p->prev = constructor_range_stack;
5465   p->next = 0;
5466   p->fields = constructor_fields;
5467   p->range_start = constructor_index;
5468   p->index = constructor_index;
5469   p->stack = constructor_stack;
5470   p->range_end = range_end;
5471   if (constructor_range_stack)
5472     constructor_range_stack->next = p;
5473   constructor_range_stack = p;
5474 }
5475
5476 /* Within an array initializer, specify the next index to be initialized.
5477    FIRST is that index.  If LAST is nonzero, then initialize a range
5478    of indices, running from FIRST through LAST.  */
5479
5480 void
5481 set_init_index (tree first, tree last)
5482 {
5483   if (set_designator (1))
5484     return;
5485
5486   designator_erroneous = 1;
5487
5488   if (!INTEGRAL_TYPE_P (TREE_TYPE (first))
5489       || (last && !INTEGRAL_TYPE_P (TREE_TYPE (last))))
5490     {
5491       error_init ("array index in initializer not of integer type");
5492       return;
5493     }
5494
5495   if (TREE_CODE (first) != INTEGER_CST)
5496     error_init ("nonconstant array index in initializer");
5497   else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
5498     error_init ("nonconstant array index in initializer");
5499   else if (TREE_CODE (constructor_type) != ARRAY_TYPE)
5500     error_init ("array index in non-array initializer");
5501   else if (tree_int_cst_sgn (first) == -1)
5502     error_init ("array index in initializer exceeds array bounds");
5503   else if (constructor_max_index
5504            && tree_int_cst_lt (constructor_max_index, first))
5505     error_init ("array index in initializer exceeds array bounds");
5506   else
5507     {
5508       constructor_index = convert (bitsizetype, first);
5509
5510       if (last)
5511         {
5512           if (tree_int_cst_equal (first, last))
5513             last = 0;
5514           else if (tree_int_cst_lt (last, first))
5515             {
5516               error_init ("empty index range in initializer");
5517               last = 0;
5518             }
5519           else
5520             {
5521               last = convert (bitsizetype, last);
5522               if (constructor_max_index != 0
5523                   && tree_int_cst_lt (constructor_max_index, last))
5524                 {
5525                   error_init ("array index range in initializer exceeds array bounds");
5526                   last = 0;
5527                 }
5528             }
5529         }
5530
5531       designator_depth++;
5532       designator_erroneous = 0;
5533       if (constructor_range_stack || last)
5534         push_range_stack (last);
5535     }
5536 }
5537
5538 /* Within a struct initializer, specify the next field to be initialized.  */
5539
5540 void
5541 set_init_label (tree fieldname)
5542 {
5543   tree tail;
5544
5545   if (set_designator (0))
5546     return;
5547
5548   designator_erroneous = 1;
5549
5550   if (TREE_CODE (constructor_type) != RECORD_TYPE
5551       && TREE_CODE (constructor_type) != UNION_TYPE)
5552     {
5553       error_init ("field name not in record or union initializer");
5554       return;
5555     }
5556
5557   for (tail = TYPE_FIELDS (constructor_type); tail;
5558        tail = TREE_CHAIN (tail))
5559     {
5560       if (DECL_NAME (tail) == fieldname)
5561         break;
5562     }
5563
5564   if (tail == 0)
5565     error ("unknown field %qE specified in initializer", fieldname);
5566   else
5567     {
5568       constructor_fields = tail;
5569       designator_depth++;
5570       designator_erroneous = 0;
5571       if (constructor_range_stack)
5572         push_range_stack (NULL_TREE);
5573     }
5574 }
5575 \f
5576 /* Add a new initializer to the tree of pending initializers.  PURPOSE
5577    identifies the initializer, either array index or field in a structure.
5578    VALUE is the value of that index or field.  */
5579
5580 static void
5581 add_pending_init (tree purpose, tree value)
5582 {
5583   struct init_node *p, **q, *r;
5584
5585   q = &constructor_pending_elts;
5586   p = 0;
5587
5588   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5589     {
5590       while (*q != 0)
5591         {
5592           p = *q;
5593           if (tree_int_cst_lt (purpose, p->purpose))
5594             q = &p->left;
5595           else if (tree_int_cst_lt (p->purpose, purpose))
5596             q = &p->right;
5597           else
5598             {
5599               if (TREE_SIDE_EFFECTS (p->value))
5600                 warning_init ("initialized field with side-effects overwritten");
5601               p->value = value;
5602               return;
5603             }
5604         }
5605     }
5606   else
5607     {
5608       tree bitpos;
5609
5610       bitpos = bit_position (purpose);
5611       while (*q != NULL)
5612         {
5613           p = *q;
5614           if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5615             q = &p->left;
5616           else if (p->purpose != purpose)
5617             q = &p->right;
5618           else
5619             {
5620               if (TREE_SIDE_EFFECTS (p->value))
5621                 warning_init ("initialized field with side-effects overwritten");
5622               p->value = value;
5623               return;
5624             }
5625         }
5626     }
5627
5628   r = GGC_NEW (struct init_node);
5629   r->purpose = purpose;
5630   r->value = value;
5631
5632   *q = r;
5633   r->parent = p;
5634   r->left = 0;
5635   r->right = 0;
5636   r->balance = 0;
5637
5638   while (p)
5639     {
5640       struct init_node *s;
5641
5642       if (r == p->left)
5643         {
5644           if (p->balance == 0)
5645             p->balance = -1;
5646           else if (p->balance < 0)
5647             {
5648               if (r->balance < 0)
5649                 {
5650                   /* L rotation.  */
5651                   p->left = r->right;
5652                   if (p->left)
5653                     p->left->parent = p;
5654                   r->right = p;
5655
5656                   p->balance = 0;
5657                   r->balance = 0;
5658
5659                   s = p->parent;
5660                   p->parent = r;
5661                   r->parent = s;
5662                   if (s)
5663                     {
5664                       if (s->left == p)
5665                         s->left = r;
5666                       else
5667                         s->right = r;
5668                     }
5669                   else
5670                     constructor_pending_elts = r;
5671                 }
5672               else
5673                 {
5674                   /* LR rotation.  */
5675                   struct init_node *t = r->right;
5676
5677                   r->right = t->left;
5678                   if (r->right)
5679                     r->right->parent = r;
5680                   t->left = r;
5681
5682                   p->left = t->right;
5683                   if (p->left)
5684                     p->left->parent = p;
5685                   t->right = p;
5686
5687                   p->balance = t->balance < 0;
5688                   r->balance = -(t->balance > 0);
5689                   t->balance = 0;
5690
5691                   s = p->parent;
5692                   p->parent = t;
5693                   r->parent = t;
5694                   t->parent = s;
5695                   if (s)
5696                     {
5697                       if (s->left == p)
5698                         s->left = t;
5699                       else
5700                         s->right = t;
5701                     }
5702                   else
5703                     constructor_pending_elts = t;
5704                 }
5705               break;
5706             }
5707           else
5708             {
5709               /* p->balance == +1; growth of left side balances the node.  */
5710               p->balance = 0;
5711               break;
5712             }
5713         }
5714       else /* r == p->right */
5715         {
5716           if (p->balance == 0)
5717             /* Growth propagation from right side.  */
5718             p->balance++;
5719           else if (p->balance > 0)
5720             {
5721               if (r->balance > 0)
5722                 {
5723                   /* R rotation.  */
5724                   p->right = r->left;
5725                   if (p->right)
5726                     p->right->parent = p;
5727                   r->left = p;
5728
5729                   p->balance = 0;
5730                   r->balance = 0;
5731
5732                   s = p->parent;
5733                   p->parent = r;
5734                   r->parent = s;
5735                   if (s)
5736                     {
5737                       if (s->left == p)
5738                         s->left = r;
5739                       else
5740                         s->right = r;
5741                     }
5742                   else
5743                     constructor_pending_elts = r;
5744                 }
5745               else /* r->balance == -1 */
5746                 {
5747                   /* RL rotation */
5748                   struct init_node *t = r->left;
5749
5750                   r->left = t->right;
5751                   if (r->left)
5752                     r->left->parent = r;
5753                   t->right = r;
5754
5755                   p->right = t->left;
5756                   if (p->right)
5757                     p->right->parent = p;
5758                   t->left = p;
5759
5760                   r->balance = (t->balance < 0);
5761                   p->balance = -(t->balance > 0);
5762                   t->balance = 0;
5763
5764                   s = p->parent;
5765                   p->parent = t;
5766                   r->parent = t;
5767                   t->parent = s;
5768                   if (s)
5769                     {
5770                       if (s->left == p)
5771                         s->left = t;
5772                       else
5773                         s->right = t;
5774                     }
5775                   else
5776                     constructor_pending_elts = t;
5777                 }
5778               break;
5779             }
5780           else
5781             {
5782               /* p->balance == -1; growth of right side balances the node.  */
5783               p->balance = 0;
5784               break;
5785             }
5786         }
5787
5788       r = p;
5789       p = p->parent;
5790     }
5791 }
5792
5793 /* Build AVL tree from a sorted chain.  */
5794
5795 static void
5796 set_nonincremental_init (void)
5797 {
5798   unsigned HOST_WIDE_INT ix;
5799   tree index, value;
5800
5801   if (TREE_CODE (constructor_type) != RECORD_TYPE
5802       && TREE_CODE (constructor_type) != ARRAY_TYPE)
5803     return;
5804
5805   FOR_EACH_CONSTRUCTOR_ELT (constructor_elements, ix, index, value)
5806     add_pending_init (index, value);
5807   constructor_elements = 0;
5808   if (TREE_CODE (constructor_type) == RECORD_TYPE)
5809     {
5810       constructor_unfilled_fields = TYPE_FIELDS (constructor_type);
5811       /* Skip any nameless bit fields at the beginning.  */
5812       while (constructor_unfilled_fields != 0
5813              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
5814              && DECL_NAME (constructor_unfilled_fields) == 0)
5815         constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
5816
5817     }
5818   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5819     {
5820       if (TYPE_DOMAIN (constructor_type))
5821         constructor_unfilled_index
5822             = convert (bitsizetype,
5823                        TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
5824       else
5825         constructor_unfilled_index = bitsize_zero_node;
5826     }
5827   constructor_incremental = 0;
5828 }
5829
5830 /* Build AVL tree from a string constant.  */
5831
5832 static void
5833 set_nonincremental_init_from_string (tree str)
5834 {
5835   tree value, purpose, type;
5836   HOST_WIDE_INT val[2];
5837   const char *p, *end;
5838   int byte, wchar_bytes, charwidth, bitpos;
5839
5840   gcc_assert (TREE_CODE (constructor_type) == ARRAY_TYPE);
5841
5842   if (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5843       == TYPE_PRECISION (char_type_node))
5844     wchar_bytes = 1;
5845   else
5846     {
5847       gcc_assert (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (str)))
5848                   == TYPE_PRECISION (wchar_type_node));
5849       wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
5850     }
5851   charwidth = TYPE_PRECISION (char_type_node);
5852   type = TREE_TYPE (constructor_type);
5853   p = TREE_STRING_POINTER (str);
5854   end = p + TREE_STRING_LENGTH (str);
5855
5856   for (purpose = bitsize_zero_node;
5857        p < end && !tree_int_cst_lt (constructor_max_index, purpose);
5858        purpose = size_binop (PLUS_EXPR, purpose, bitsize_one_node))
5859     {
5860       if (wchar_bytes == 1)
5861         {
5862           val[1] = (unsigned char) *p++;
5863           val[0] = 0;
5864         }
5865       else
5866         {
5867           val[0] = 0;
5868           val[1] = 0;
5869           for (byte = 0; byte < wchar_bytes; byte++)
5870             {
5871               if (BYTES_BIG_ENDIAN)
5872                 bitpos = (wchar_bytes - byte - 1) * charwidth;
5873               else
5874                 bitpos = byte * charwidth;
5875               val[bitpos < HOST_BITS_PER_WIDE_INT]
5876                 |= ((unsigned HOST_WIDE_INT) ((unsigned char) *p++))
5877                    << (bitpos % HOST_BITS_PER_WIDE_INT);
5878             }
5879         }
5880
5881       if (!TYPE_UNSIGNED (type))
5882         {
5883           bitpos = ((wchar_bytes - 1) * charwidth) + HOST_BITS_PER_CHAR;
5884           if (bitpos < HOST_BITS_PER_WIDE_INT)
5885             {
5886               if (val[1] & (((HOST_WIDE_INT) 1) << (bitpos - 1)))
5887                 {
5888                   val[1] |= ((HOST_WIDE_INT) -1) << bitpos;
5889                   val[0] = -1;
5890                 }
5891             }
5892           else if (bitpos == HOST_BITS_PER_WIDE_INT)
5893             {
5894               if (val[1] < 0)
5895                 val[0] = -1;
5896             }
5897           else if (val[0] & (((HOST_WIDE_INT) 1)
5898                              << (bitpos - 1 - HOST_BITS_PER_WIDE_INT)))
5899             val[0] |= ((HOST_WIDE_INT) -1)
5900                       << (bitpos - HOST_BITS_PER_WIDE_INT);
5901         }
5902
5903       value = build_int_cst_wide (type, val[1], val[0]);
5904       add_pending_init (purpose, value);
5905     }
5906
5907   constructor_incremental = 0;
5908 }
5909
5910 /* Return value of FIELD in pending initializer or zero if the field was
5911    not initialized yet.  */
5912
5913 static tree
5914 find_init_member (tree field)
5915 {
5916   struct init_node *p;
5917
5918   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
5919     {
5920       if (constructor_incremental
5921           && tree_int_cst_lt (field, constructor_unfilled_index))
5922         set_nonincremental_init ();
5923
5924       p = constructor_pending_elts;
5925       while (p)
5926         {
5927           if (tree_int_cst_lt (field, p->purpose))
5928             p = p->left;
5929           else if (tree_int_cst_lt (p->purpose, field))
5930             p = p->right;
5931           else
5932             return p->value;
5933         }
5934     }
5935   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
5936     {
5937       tree bitpos = bit_position (field);
5938
5939       if (constructor_incremental
5940           && (!constructor_unfilled_fields
5941               || tree_int_cst_lt (bitpos,
5942                                   bit_position (constructor_unfilled_fields))))
5943         set_nonincremental_init ();
5944
5945       p = constructor_pending_elts;
5946       while (p)
5947         {
5948           if (field == p->purpose)
5949             return p->value;
5950           else if (tree_int_cst_lt (bitpos, bit_position (p->purpose)))
5951             p = p->left;
5952           else
5953             p = p->right;
5954         }
5955     }
5956   else if (TREE_CODE (constructor_type) == UNION_TYPE)
5957     {
5958       if (!VEC_empty (constructor_elt, constructor_elements)
5959           && (VEC_last (constructor_elt, constructor_elements)->index
5960               == field))
5961         return VEC_last (constructor_elt, constructor_elements)->value;
5962     }
5963   return 0;
5964 }
5965
5966 /* "Output" the next constructor element.
5967    At top level, really output it to assembler code now.
5968    Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5969    TYPE is the data type that the containing data type wants here.
5970    FIELD is the field (a FIELD_DECL) or the index that this element fills.
5971    If VALUE is a string constant, STRICT_STRING is true if it is
5972    unparenthesized or we should not warn here for it being parenthesized.
5973    For other types of VALUE, STRICT_STRING is not used.
5974
5975    PENDING if non-nil means output pending elements that belong
5976    right after this element.  (PENDING is normally 1;
5977    it is 0 while outputting pending elements, to avoid recursion.)  */
5978
5979 static void
5980 output_init_element (tree value, bool strict_string, tree type, tree field,
5981                      int pending)
5982 {
5983   constructor_elt *celt;
5984
5985   if (type == error_mark_node || value == error_mark_node)
5986     {
5987       constructor_erroneous = 1;
5988       return;
5989     }
5990   if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
5991       && (TREE_CODE (value) == STRING_CST
5992           || TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
5993       && !(TREE_CODE (value) == STRING_CST
5994            && TREE_CODE (type) == ARRAY_TYPE
5995            && INTEGRAL_TYPE_P (TREE_TYPE (type)))
5996       && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
5997                      TYPE_MAIN_VARIANT (type)))
5998     value = array_to_pointer_conversion (value);
5999
6000   if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR
6001       && require_constant_value && !flag_isoc99 && pending)
6002     {
6003       /* As an extension, allow initializing objects with static storage
6004          duration with compound literals (which are then treated just as
6005          the brace enclosed list they contain).  */
6006       tree decl = COMPOUND_LITERAL_EXPR_DECL (value);
6007       value = DECL_INITIAL (decl);
6008     }
6009
6010   if (value == error_mark_node)
6011     constructor_erroneous = 1;
6012   else if (!TREE_CONSTANT (value))
6013     constructor_constant = 0;
6014   else if (!initializer_constant_valid_p (value, TREE_TYPE (value))
6015            || ((TREE_CODE (constructor_type) == RECORD_TYPE
6016                 || TREE_CODE (constructor_type) == UNION_TYPE)
6017                && DECL_C_BIT_FIELD (field)
6018                && TREE_CODE (value) != INTEGER_CST))
6019     constructor_simple = 0;
6020
6021   if (!initializer_constant_valid_p (value, TREE_TYPE (value)))
6022     {
6023       if (require_constant_value)
6024         {
6025           error_init ("initializer element is not constant");
6026           value = error_mark_node;
6027         }
6028       else if (require_constant_elements)
6029         pedwarn ("initializer element is not computable at load time");
6030     }
6031
6032   /* If this field is empty (and not at the end of structure),
6033      don't do anything other than checking the initializer.  */
6034   if (field
6035       && (TREE_TYPE (field) == error_mark_node
6036           || (COMPLETE_TYPE_P (TREE_TYPE (field))
6037               && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))
6038               && (TREE_CODE (constructor_type) == ARRAY_TYPE
6039                   || TREE_CHAIN (field)))))
6040     return;
6041
6042   value = digest_init (type, value, strict_string, require_constant_value);
6043   if (value == error_mark_node)
6044     {
6045       constructor_erroneous = 1;
6046       return;
6047     }
6048
6049   /* If this element doesn't come next in sequence,
6050      put it on constructor_pending_elts.  */
6051   if (TREE_CODE (constructor_type) == ARRAY_TYPE
6052       && (!constructor_incremental
6053           || !tree_int_cst_equal (field, constructor_unfilled_index)))
6054     {
6055       if (constructor_incremental
6056           && tree_int_cst_lt (field, constructor_unfilled_index))
6057         set_nonincremental_init ();
6058
6059       add_pending_init (field, value);
6060       return;
6061     }
6062   else if (TREE_CODE (constructor_type) == RECORD_TYPE
6063            && (!constructor_incremental
6064                || field != constructor_unfilled_fields))
6065     {
6066       /* We do this for records but not for unions.  In a union,
6067          no matter which field is specified, it can be initialized
6068          right away since it starts at the beginning of the union.  */
6069       if (constructor_incremental)
6070         {
6071           if (!constructor_unfilled_fields)
6072             set_nonincremental_init ();
6073           else
6074             {
6075               tree bitpos, unfillpos;
6076
6077               bitpos = bit_position (field);
6078               unfillpos = bit_position (constructor_unfilled_fields);
6079
6080               if (tree_int_cst_lt (bitpos, unfillpos))
6081                 set_nonincremental_init ();
6082             }
6083         }
6084
6085       add_pending_init (field, value);
6086       return;
6087     }
6088   else if (TREE_CODE (constructor_type) == UNION_TYPE
6089            && !VEC_empty (constructor_elt, constructor_elements))
6090     {
6091       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
6092                                        constructor_elements)->value))
6093         warning_init ("initialized field with side-effects overwritten");
6094
6095       /* We can have just one union field set.  */
6096       constructor_elements = 0;
6097     }
6098
6099   /* Otherwise, output this element either to
6100      constructor_elements or to the assembler file.  */
6101
6102   celt = VEC_safe_push (constructor_elt, gc, constructor_elements, NULL);
6103   celt->index = field;
6104   celt->value = value;
6105
6106   /* Advance the variable that indicates sequential elements output.  */
6107   if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6108     constructor_unfilled_index
6109       = size_binop (PLUS_EXPR, constructor_unfilled_index,
6110                     bitsize_one_node);
6111   else if (TREE_CODE (constructor_type) == RECORD_TYPE)
6112     {
6113       constructor_unfilled_fields
6114         = TREE_CHAIN (constructor_unfilled_fields);
6115
6116       /* Skip any nameless bit fields.  */
6117       while (constructor_unfilled_fields != 0
6118              && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6119              && DECL_NAME (constructor_unfilled_fields) == 0)
6120         constructor_unfilled_fields =
6121           TREE_CHAIN (constructor_unfilled_fields);
6122     }
6123   else if (TREE_CODE (constructor_type) == UNION_TYPE)
6124     constructor_unfilled_fields = 0;
6125
6126   /* Now output any pending elements which have become next.  */
6127   if (pending)
6128     output_pending_init_elements (0);
6129 }
6130
6131 /* Output any pending elements which have become next.
6132    As we output elements, constructor_unfilled_{fields,index}
6133    advances, which may cause other elements to become next;
6134    if so, they too are output.
6135
6136    If ALL is 0, we return when there are
6137    no more pending elements to output now.
6138
6139    If ALL is 1, we output space as necessary so that
6140    we can output all the pending elements.  */
6141
6142 static void
6143 output_pending_init_elements (int all)
6144 {
6145   struct init_node *elt = constructor_pending_elts;
6146   tree next;
6147
6148  retry:
6149
6150   /* Look through the whole pending tree.
6151      If we find an element that should be output now,
6152      output it.  Otherwise, set NEXT to the element
6153      that comes first among those still pending.  */
6154
6155   next = 0;
6156   while (elt)
6157     {
6158       if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6159         {
6160           if (tree_int_cst_equal (elt->purpose,
6161                                   constructor_unfilled_index))
6162             output_init_element (elt->value, true,
6163                                  TREE_TYPE (constructor_type),
6164                                  constructor_unfilled_index, 0);
6165           else if (tree_int_cst_lt (constructor_unfilled_index,
6166                                     elt->purpose))
6167             {
6168               /* Advance to the next smaller node.  */
6169               if (elt->left)
6170                 elt = elt->left;
6171               else
6172                 {
6173                   /* We have reached the smallest node bigger than the
6174                      current unfilled index.  Fill the space first.  */
6175                   next = elt->purpose;
6176                   break;
6177                 }
6178             }
6179           else
6180             {
6181               /* Advance to the next bigger node.  */
6182               if (elt->right)
6183                 elt = elt->right;
6184               else
6185                 {
6186                   /* We have reached the biggest node in a subtree.  Find
6187                      the parent of it, which is the next bigger node.  */
6188                   while (elt->parent && elt->parent->right == elt)
6189                     elt = elt->parent;
6190                   elt = elt->parent;
6191                   if (elt && tree_int_cst_lt (constructor_unfilled_index,
6192                                               elt->purpose))
6193                     {
6194                       next = elt->purpose;
6195                       break;
6196                     }
6197                 }
6198             }
6199         }
6200       else if (TREE_CODE (constructor_type) == RECORD_TYPE
6201                || TREE_CODE (constructor_type) == UNION_TYPE)
6202         {
6203           tree ctor_unfilled_bitpos, elt_bitpos;
6204
6205           /* If the current record is complete we are done.  */
6206           if (constructor_unfilled_fields == 0)
6207             break;
6208
6209           ctor_unfilled_bitpos = bit_position (constructor_unfilled_fields);
6210           elt_bitpos = bit_position (elt->purpose);
6211           /* We can't compare fields here because there might be empty
6212              fields in between.  */
6213           if (tree_int_cst_equal (elt_bitpos, ctor_unfilled_bitpos))
6214             {
6215               constructor_unfilled_fields = elt->purpose;
6216               output_init_element (elt->value, true, TREE_TYPE (elt->purpose),
6217                                    elt->purpose, 0);
6218             }
6219           else if (tree_int_cst_lt (ctor_unfilled_bitpos, elt_bitpos))
6220             {
6221               /* Advance to the next smaller node.  */
6222               if (elt->left)
6223                 elt = elt->left;
6224               else
6225                 {
6226                   /* We have reached the smallest node bigger than the
6227                      current unfilled field.  Fill the space first.  */
6228                   next = elt->purpose;
6229                   break;
6230                 }
6231             }
6232           else
6233             {
6234               /* Advance to the next bigger node.  */
6235               if (elt->right)
6236                 elt = elt->right;
6237               else
6238                 {
6239                   /* We have reached the biggest node in a subtree.  Find
6240                      the parent of it, which is the next bigger node.  */
6241                   while (elt->parent && elt->parent->right == elt)
6242                     elt = elt->parent;
6243                   elt = elt->parent;
6244                   if (elt
6245                       && (tree_int_cst_lt (ctor_unfilled_bitpos,
6246                                            bit_position (elt->purpose))))
6247                     {
6248                       next = elt->purpose;
6249                       break;
6250                     }
6251                 }
6252             }
6253         }
6254     }
6255
6256   /* Ordinarily return, but not if we want to output all
6257      and there are elements left.  */
6258   if (!(all && next != 0))
6259     return;
6260
6261   /* If it's not incremental, just skip over the gap, so that after
6262      jumping to retry we will output the next successive element.  */
6263   if (TREE_CODE (constructor_type) == RECORD_TYPE
6264       || TREE_CODE (constructor_type) == UNION_TYPE)
6265     constructor_unfilled_fields = next;
6266   else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6267     constructor_unfilled_index = next;
6268
6269   /* ELT now points to the node in the pending tree with the next
6270      initializer to output.  */
6271   goto retry;
6272 }
6273 \f
6274 /* Add one non-braced element to the current constructor level.
6275    This adjusts the current position within the constructor's type.
6276    This may also start or terminate implicit levels
6277    to handle a partly-braced initializer.
6278
6279    Once this has found the correct level for the new element,
6280    it calls output_init_element.  */
6281
6282 void
6283 process_init_element (struct c_expr value)
6284 {
6285   tree orig_value = value.value;
6286   int string_flag = orig_value != 0 && TREE_CODE (orig_value) == STRING_CST;
6287   bool strict_string = value.original_code == STRING_CST;
6288
6289   designator_depth = 0;
6290   designator_erroneous = 0;
6291
6292   /* Handle superfluous braces around string cst as in
6293      char x[] = {"foo"}; */
6294   if (string_flag
6295       && constructor_type
6296       && TREE_CODE (constructor_type) == ARRAY_TYPE
6297       && INTEGRAL_TYPE_P (TREE_TYPE (constructor_type))
6298       && integer_zerop (constructor_unfilled_index))
6299     {
6300       if (constructor_stack->replacement_value.value)
6301         error_init ("excess elements in char array initializer");
6302       constructor_stack->replacement_value = value;
6303       return;
6304     }
6305
6306   if (constructor_stack->replacement_value.value != 0)
6307     {
6308       error_init ("excess elements in struct initializer");
6309       return;
6310     }
6311
6312   /* Ignore elements of a brace group if it is entirely superfluous
6313      and has already been diagnosed.  */
6314   if (constructor_type == 0)
6315     return;
6316
6317   /* If we've exhausted any levels that didn't have braces,
6318      pop them now.  */
6319   while (constructor_stack->implicit)
6320     {
6321       if ((TREE_CODE (constructor_type) == RECORD_TYPE
6322            || TREE_CODE (constructor_type) == UNION_TYPE)
6323           && constructor_fields == 0)
6324         process_init_element (pop_init_level (1));
6325       else if (TREE_CODE (constructor_type) == ARRAY_TYPE
6326                && (constructor_max_index == 0
6327                    || tree_int_cst_lt (constructor_max_index,
6328                                        constructor_index)))
6329         process_init_element (pop_init_level (1));
6330       else
6331         break;
6332     }
6333
6334   /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once.  */
6335   if (constructor_range_stack)
6336     {
6337       /* If value is a compound literal and we'll be just using its
6338          content, don't put it into a SAVE_EXPR.  */
6339       if (TREE_CODE (value.value) != COMPOUND_LITERAL_EXPR
6340           || !require_constant_value
6341           || flag_isoc99)
6342         value.value = save_expr (value.value);
6343     }
6344
6345   while (1)
6346     {
6347       if (TREE_CODE (constructor_type) == RECORD_TYPE)
6348         {
6349           tree fieldtype;
6350           enum tree_code fieldcode;
6351
6352           if (constructor_fields == 0)
6353             {
6354               pedwarn_init ("excess elements in struct initializer");
6355               break;
6356             }
6357
6358           fieldtype = TREE_TYPE (constructor_fields);
6359           if (fieldtype != error_mark_node)
6360             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6361           fieldcode = TREE_CODE (fieldtype);
6362
6363           /* Error for non-static initialization of a flexible array member.  */
6364           if (fieldcode == ARRAY_TYPE
6365               && !require_constant_value
6366               && TYPE_SIZE (fieldtype) == NULL_TREE
6367               && TREE_CHAIN (constructor_fields) == NULL_TREE)
6368             {
6369               error_init ("non-static initialization of a flexible array member");
6370               break;
6371             }
6372
6373           /* Accept a string constant to initialize a subarray.  */
6374           if (value.value != 0
6375               && fieldcode == ARRAY_TYPE
6376               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6377               && string_flag)
6378             value.value = orig_value;
6379           /* Otherwise, if we have come to a subaggregate,
6380              and we don't have an element of its type, push into it.  */
6381           else if (value.value != 0
6382                    && value.value != error_mark_node
6383                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6384                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6385                        || fieldcode == UNION_TYPE))
6386             {
6387               push_init_level (1);
6388               continue;
6389             }
6390
6391           if (value.value)
6392             {
6393               push_member_name (constructor_fields);
6394               output_init_element (value.value, strict_string,
6395                                    fieldtype, constructor_fields, 1);
6396               RESTORE_SPELLING_DEPTH (constructor_depth);
6397             }
6398           else
6399             /* Do the bookkeeping for an element that was
6400                directly output as a constructor.  */
6401             {
6402               /* For a record, keep track of end position of last field.  */
6403               if (DECL_SIZE (constructor_fields))
6404                 constructor_bit_index
6405                   = size_binop (PLUS_EXPR,
6406                                 bit_position (constructor_fields),
6407                                 DECL_SIZE (constructor_fields));
6408
6409               /* If the current field was the first one not yet written out,
6410                  it isn't now, so update.  */
6411               if (constructor_unfilled_fields == constructor_fields)
6412                 {
6413                   constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6414                   /* Skip any nameless bit fields.  */
6415                   while (constructor_unfilled_fields != 0
6416                          && DECL_C_BIT_FIELD (constructor_unfilled_fields)
6417                          && DECL_NAME (constructor_unfilled_fields) == 0)
6418                     constructor_unfilled_fields =
6419                       TREE_CHAIN (constructor_unfilled_fields);
6420                 }
6421             }
6422
6423           constructor_fields = TREE_CHAIN (constructor_fields);
6424           /* Skip any nameless bit fields at the beginning.  */
6425           while (constructor_fields != 0
6426                  && DECL_C_BIT_FIELD (constructor_fields)
6427                  && DECL_NAME (constructor_fields) == 0)
6428             constructor_fields = TREE_CHAIN (constructor_fields);
6429         }
6430       else if (TREE_CODE (constructor_type) == UNION_TYPE)
6431         {
6432           tree fieldtype;
6433           enum tree_code fieldcode;
6434
6435           if (constructor_fields == 0)
6436             {
6437               pedwarn_init ("excess elements in union initializer");
6438               break;
6439             }
6440
6441           fieldtype = TREE_TYPE (constructor_fields);
6442           if (fieldtype != error_mark_node)
6443             fieldtype = TYPE_MAIN_VARIANT (fieldtype);
6444           fieldcode = TREE_CODE (fieldtype);
6445
6446           /* Warn that traditional C rejects initialization of unions.
6447              We skip the warning if the value is zero.  This is done
6448              under the assumption that the zero initializer in user
6449              code appears conditioned on e.g. __STDC__ to avoid
6450              "missing initializer" warnings and relies on default
6451              initialization to zero in the traditional C case.
6452              We also skip the warning if the initializer is designated,
6453              again on the assumption that this must be conditional on
6454              __STDC__ anyway (and we've already complained about the
6455              member-designator already).  */
6456           if (!in_system_header && !constructor_designated
6457               && !(value.value && (integer_zerop (value.value)
6458                                    || real_zerop (value.value))))
6459             warning (OPT_Wtraditional, "traditional C rejects initialization "
6460                      "of unions");
6461
6462           /* Accept a string constant to initialize a subarray.  */
6463           if (value.value != 0
6464               && fieldcode == ARRAY_TYPE
6465               && INTEGRAL_TYPE_P (TREE_TYPE (fieldtype))
6466               && string_flag)
6467             value.value = orig_value;
6468           /* Otherwise, if we have come to a subaggregate,
6469              and we don't have an element of its type, push into it.  */
6470           else if (value.value != 0
6471                    && value.value != error_mark_node
6472                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != fieldtype
6473                    && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
6474                        || fieldcode == UNION_TYPE))
6475             {
6476               push_init_level (1);
6477               continue;
6478             }
6479
6480           if (value.value)
6481             {
6482               push_member_name (constructor_fields);
6483               output_init_element (value.value, strict_string,
6484                                    fieldtype, constructor_fields, 1);
6485               RESTORE_SPELLING_DEPTH (constructor_depth);
6486             }
6487           else
6488             /* Do the bookkeeping for an element that was
6489                directly output as a constructor.  */
6490             {
6491               constructor_bit_index = DECL_SIZE (constructor_fields);
6492               constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
6493             }
6494
6495           constructor_fields = 0;
6496         }
6497       else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
6498         {
6499           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6500           enum tree_code eltcode = TREE_CODE (elttype);
6501
6502           /* Accept a string constant to initialize a subarray.  */
6503           if (value.value != 0
6504               && eltcode == ARRAY_TYPE
6505               && INTEGRAL_TYPE_P (TREE_TYPE (elttype))
6506               && string_flag)
6507             value.value = orig_value;
6508           /* Otherwise, if we have come to a subaggregate,
6509              and we don't have an element of its type, push into it.  */
6510           else if (value.value != 0
6511                    && value.value != error_mark_node
6512                    && TYPE_MAIN_VARIANT (TREE_TYPE (value.value)) != elttype
6513                    && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
6514                        || eltcode == UNION_TYPE))
6515             {
6516               push_init_level (1);
6517               continue;
6518             }
6519
6520           if (constructor_max_index != 0
6521               && (tree_int_cst_lt (constructor_max_index, constructor_index)
6522                   || integer_all_onesp (constructor_max_index)))
6523             {
6524               pedwarn_init ("excess elements in array initializer");
6525               break;
6526             }
6527
6528           /* Now output the actual element.  */
6529           if (value.value)
6530             {
6531               push_array_bounds (tree_low_cst (constructor_index, 1));
6532               output_init_element (value.value, strict_string,
6533                                    elttype, constructor_index, 1);
6534               RESTORE_SPELLING_DEPTH (constructor_depth);
6535             }
6536
6537           constructor_index
6538             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6539
6540           if (!value.value)
6541             /* If we are doing the bookkeeping for an element that was
6542                directly output as a constructor, we must update
6543                constructor_unfilled_index.  */
6544             constructor_unfilled_index = constructor_index;
6545         }
6546       else if (TREE_CODE (constructor_type) == VECTOR_TYPE)
6547         {
6548           tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
6549
6550          /* Do a basic check of initializer size.  Note that vectors
6551             always have a fixed size derived from their type.  */
6552           if (tree_int_cst_lt (constructor_max_index, constructor_index))
6553             {
6554               pedwarn_init ("excess elements in vector initializer");
6555               break;
6556             }
6557
6558           /* Now output the actual element.  */
6559           if (value.value)
6560             output_init_element (value.value, strict_string,
6561                                  elttype, constructor_index, 1);
6562
6563           constructor_index
6564             = size_binop (PLUS_EXPR, constructor_index, bitsize_one_node);
6565
6566           if (!value.value)
6567             /* If we are doing the bookkeeping for an element that was
6568                directly output as a constructor, we must update
6569                constructor_unfilled_index.  */
6570             constructor_unfilled_index = constructor_index;
6571         }
6572
6573       /* Handle the sole element allowed in a braced initializer
6574          for a scalar variable.  */
6575       else if (constructor_type != error_mark_node
6576                && constructor_fields == 0)
6577         {
6578           pedwarn_init ("excess elements in scalar initializer");
6579           break;
6580         }
6581       else
6582         {
6583           if (value.value)
6584             output_init_element (value.value, strict_string,
6585                                  constructor_type, NULL_TREE, 1);
6586           constructor_fields = 0;
6587         }
6588
6589       /* Handle range initializers either at this level or anywhere higher
6590          in the designator stack.  */
6591       if (constructor_range_stack)
6592         {
6593           struct constructor_range_stack *p, *range_stack;
6594           int finish = 0;
6595
6596           range_stack = constructor_range_stack;
6597           constructor_range_stack = 0;
6598           while (constructor_stack != range_stack->stack)
6599             {
6600               gcc_assert (constructor_stack->implicit);
6601               process_init_element (pop_init_level (1));
6602             }
6603           for (p = range_stack;
6604                !p->range_end || tree_int_cst_equal (p->index, p->range_end);
6605                p = p->prev)
6606             {
6607               gcc_assert (constructor_stack->implicit);
6608               process_init_element (pop_init_level (1));
6609             }
6610
6611           p->index = size_binop (PLUS_EXPR, p->index, bitsize_one_node);
6612           if (tree_int_cst_equal (p->index, p->range_end) && !p->prev)
6613             finish = 1;
6614
6615           while (1)
6616             {
6617               constructor_index = p->index;
6618               constructor_fields = p->fields;
6619               if (finish && p->range_end && p->index == p->range_start)
6620                 {
6621                   finish = 0;
6622                   p->prev = 0;
6623                 }
6624               p = p->next;
6625               if (!p)
6626                 break;
6627               push_init_level (2);
6628               p->stack = constructor_stack;
6629               if (p->range_end && tree_int_cst_equal (p->index, p->range_end))
6630                 p->index = p->range_start;
6631             }
6632
6633           if (!finish)
6634             constructor_range_stack = range_stack;
6635           continue;
6636         }
6637
6638       break;
6639     }
6640
6641   constructor_range_stack = 0;
6642 }
6643 \f
6644 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6645    (guaranteed to be 'volatile' or null) and ARGS (represented using
6646    an ASM_EXPR node).  */
6647 tree
6648 build_asm_stmt (tree cv_qualifier, tree args)
6649 {
6650   if (!ASM_VOLATILE_P (args) && cv_qualifier)
6651     ASM_VOLATILE_P (args) = 1;
6652   return add_stmt (args);
6653 }
6654
6655 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6656    some INPUTS, and some CLOBBERS.  The latter three may be NULL.
6657    SIMPLE indicates whether there was anything at all after the
6658    string in the asm expression -- asm("blah") and asm("blah" : )
6659    are subtly different.  We use a ASM_EXPR node to represent this.  */
6660 tree
6661 build_asm_expr (tree string, tree outputs, tree inputs, tree clobbers,
6662                 bool simple)
6663 {
6664   tree tail;
6665   tree args;
6666   int i;
6667   const char *constraint;
6668   const char **oconstraints;
6669   bool allows_mem, allows_reg, is_inout;
6670   int ninputs, noutputs;
6671
6672   ninputs = list_length (inputs);
6673   noutputs = list_length (outputs);
6674   oconstraints = (const char **) alloca (noutputs * sizeof (const char *));
6675
6676   string = resolve_asm_operand_names (string, outputs, inputs);
6677
6678   /* Remove output conversions that change the type but not the mode.  */
6679   for (i = 0, tail = outputs; tail; ++i, tail = TREE_CHAIN (tail))
6680     {
6681       tree output = TREE_VALUE (tail);
6682
6683       /* ??? Really, this should not be here.  Users should be using a
6684          proper lvalue, dammit.  But there's a long history of using casts
6685          in the output operands.  In cases like longlong.h, this becomes a
6686          primitive form of typechecking -- if the cast can be removed, then
6687          the output operand had a type of the proper width; otherwise we'll
6688          get an error.  Gross, but ...  */
6689       STRIP_NOPS (output);
6690
6691       if (!lvalue_or_else (output, lv_asm))
6692         output = error_mark_node;
6693
6694       if (output != error_mark_node
6695           && (TREE_READONLY (output)
6696               || TYPE_READONLY (TREE_TYPE (output))
6697               || ((TREE_CODE (TREE_TYPE (output)) == RECORD_TYPE
6698                    || TREE_CODE (TREE_TYPE (output)) == UNION_TYPE)
6699                   && C_TYPE_FIELDS_READONLY (TREE_TYPE (output)))))
6700         readonly_error (output, lv_asm);
6701
6702       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6703       oconstraints[i] = constraint;
6704
6705       if (parse_output_constraint (&constraint, i, ninputs, noutputs,
6706                                    &allows_mem, &allows_reg, &is_inout))
6707         {
6708           /* If the operand is going to end up in memory,
6709              mark it addressable.  */
6710           if (!allows_reg && !c_mark_addressable (output))
6711             output = error_mark_node;
6712         }
6713       else
6714         output = error_mark_node;
6715
6716       TREE_VALUE (tail) = output;
6717     }
6718
6719   for (i = 0, tail = inputs; tail; ++i, tail = TREE_CHAIN (tail))
6720     {
6721       tree input;
6722
6723       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tail)));
6724       input = TREE_VALUE (tail);
6725
6726       if (parse_input_constraint (&constraint, i, ninputs, noutputs, 0,
6727                                   oconstraints, &allows_mem, &allows_reg))
6728         {
6729           /* If the operand is going to end up in memory,
6730              mark it addressable.  */
6731           if (!allows_reg && allows_mem)
6732             {
6733               /* Strip the nops as we allow this case.  FIXME, this really
6734                  should be rejected or made deprecated.  */
6735               STRIP_NOPS (input);
6736               if (!c_mark_addressable (input))
6737                 input = error_mark_node;
6738           }
6739         }
6740       else
6741         input = error_mark_node;
6742
6743       TREE_VALUE (tail) = input;
6744     }
6745
6746   args = build_stmt (ASM_EXPR, string, outputs, inputs, clobbers);
6747
6748   /* asm statements without outputs, including simple ones, are treated
6749      as volatile.  */
6750   ASM_INPUT_P (args) = simple;
6751   ASM_VOLATILE_P (args) = (noutputs == 0);
6752
6753   return args;
6754 }
6755 \f
6756 /* Generate a goto statement to LABEL.  */
6757
6758 tree
6759 c_finish_goto_label (tree label)
6760 {
6761   tree decl = lookup_label (label);
6762   if (!decl)
6763     return NULL_TREE;
6764
6765   if (C_DECL_UNJUMPABLE_STMT_EXPR (decl))
6766     {
6767       error ("jump into statement expression");
6768       return NULL_TREE;
6769     }
6770
6771   if (C_DECL_UNJUMPABLE_VM (decl))
6772     {
6773       error ("jump into scope of identifier with variably modified type");
6774       return NULL_TREE;
6775     }
6776
6777   if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
6778     {
6779       /* No jump from outside this statement expression context, so
6780          record that there is a jump from within this context.  */
6781       struct c_label_list *nlist;
6782       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6783       nlist->next = label_context_stack_se->labels_used;
6784       nlist->label = decl;
6785       label_context_stack_se->labels_used = nlist;
6786     }
6787
6788   if (!C_DECL_UNDEFINABLE_VM (decl))
6789     {
6790       /* No jump from outside this context context of identifiers with
6791          variably modified type, so record that there is a jump from
6792          within this context.  */
6793       struct c_label_list *nlist;
6794       nlist = XOBNEW (&parser_obstack, struct c_label_list);
6795       nlist->next = label_context_stack_vm->labels_used;
6796       nlist->label = decl;
6797       label_context_stack_vm->labels_used = nlist;
6798     }
6799
6800   TREE_USED (decl) = 1;
6801   return add_stmt (build1 (GOTO_EXPR, void_type_node, decl));
6802 }
6803
6804 /* Generate a computed goto statement to EXPR.  */
6805
6806 tree
6807 c_finish_goto_ptr (tree expr)
6808 {
6809   if (pedantic)
6810     pedwarn ("ISO C forbids %<goto *expr;%>");
6811   expr = convert (ptr_type_node, expr);
6812   return add_stmt (build1 (GOTO_EXPR, void_type_node, expr));
6813 }
6814
6815 /* Generate a C `return' statement.  RETVAL is the expression for what
6816    to return, or a null pointer for `return;' with no value.  */
6817
6818 tree
6819 c_finish_return (tree retval)
6820 {
6821   tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt;
6822   bool no_warning = false;
6823
6824   if (TREE_THIS_VOLATILE (current_function_decl))
6825     warning (0, "function declared %<noreturn%> has a %<return%> statement");
6826
6827   if (!retval)
6828     {
6829       current_function_returns_null = 1;
6830       if ((warn_return_type || flag_isoc99)
6831           && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
6832         {
6833           pedwarn_c99 ("%<return%> with no value, in "
6834                        "function returning non-void");
6835           no_warning = true;
6836         }
6837     }
6838   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
6839     {
6840       current_function_returns_null = 1;
6841       if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
6842         pedwarn ("%<return%> with a value, in function returning void");
6843     }
6844   else
6845     {
6846       tree t = convert_for_assignment (valtype, retval, ic_return,
6847                                        NULL_TREE, NULL_TREE, 0);
6848       tree res = DECL_RESULT (current_function_decl);
6849       tree inner;
6850
6851       current_function_returns_value = 1;
6852       if (t == error_mark_node)
6853         return NULL_TREE;
6854
6855       inner = t = convert (TREE_TYPE (res), t);
6856
6857       /* Strip any conversions, additions, and subtractions, and see if
6858          we are returning the address of a local variable.  Warn if so.  */
6859       while (1)
6860         {
6861           switch (TREE_CODE (inner))
6862             {
6863             case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
6864             case PLUS_EXPR:
6865               inner = TREE_OPERAND (inner, 0);
6866               continue;
6867
6868             case MINUS_EXPR:
6869               /* If the second operand of the MINUS_EXPR has a pointer
6870                  type (or is converted from it), this may be valid, so
6871                  don't give a warning.  */
6872               {
6873                 tree op1 = TREE_OPERAND (inner, 1);
6874
6875                 while (!POINTER_TYPE_P (TREE_TYPE (op1))
6876                        && (TREE_CODE (op1) == NOP_EXPR
6877                            || TREE_CODE (op1) == NON_LVALUE_EXPR
6878                            || TREE_CODE (op1) == CONVERT_EXPR))
6879                   op1 = TREE_OPERAND (op1, 0);
6880
6881                 if (POINTER_TYPE_P (TREE_TYPE (op1)))
6882                   break;
6883
6884                 inner = TREE_OPERAND (inner, 0);
6885                 continue;
6886               }
6887
6888             case ADDR_EXPR:
6889               inner = TREE_OPERAND (inner, 0);
6890
6891               while (REFERENCE_CLASS_P (inner)
6892                      && TREE_CODE (inner) != INDIRECT_REF)
6893                 inner = TREE_OPERAND (inner, 0);
6894
6895               if (DECL_P (inner)
6896                   && !DECL_EXTERNAL (inner)
6897                   && !TREE_STATIC (inner)
6898                   && DECL_CONTEXT (inner) == current_function_decl)
6899                 warning (0, "function returns address of local variable");
6900               break;
6901
6902             default:
6903               break;
6904             }
6905
6906           break;
6907         }
6908
6909       retval = build2 (MODIFY_EXPR, TREE_TYPE (res), res, t);
6910     }
6911
6912   ret_stmt = build_stmt (RETURN_EXPR, retval);
6913   TREE_NO_WARNING (ret_stmt) |= no_warning;
6914   return add_stmt (ret_stmt);
6915 }
6916 \f
6917 struct c_switch {
6918   /* The SWITCH_EXPR being built.  */
6919   tree switch_expr;
6920
6921   /* The original type of the testing expression, i.e. before the
6922      default conversion is applied.  */
6923   tree orig_type;
6924
6925   /* A splay-tree mapping the low element of a case range to the high
6926      element, or NULL_TREE if there is no high element.  Used to
6927      determine whether or not a new case label duplicates an old case
6928      label.  We need a tree, rather than simply a hash table, because
6929      of the GNU case range extension.  */
6930   splay_tree cases;
6931
6932   /* Number of nested statement expressions within this switch
6933      statement; if nonzero, case and default labels may not
6934      appear.  */
6935   unsigned int blocked_stmt_expr;
6936
6937   /* Scope of outermost declarations of identifiers with variably
6938      modified type within this switch statement; if nonzero, case and
6939      default labels may not appear.  */
6940   unsigned int blocked_vm;
6941
6942   /* The next node on the stack.  */
6943   struct c_switch *next;
6944 };
6945
6946 /* A stack of the currently active switch statements.  The innermost
6947    switch statement is on the top of the stack.  There is no need to
6948    mark the stack for garbage collection because it is only active
6949    during the processing of the body of a function, and we never
6950    collect at that point.  */
6951
6952 struct c_switch *c_switch_stack;
6953
6954 /* Start a C switch statement, testing expression EXP.  Return the new
6955    SWITCH_EXPR.  */
6956
6957 tree
6958 c_start_case (tree exp)
6959 {
6960   enum tree_code code;
6961   tree type, orig_type = error_mark_node;
6962   struct c_switch *cs;
6963
6964   if (exp != error_mark_node)
6965     {
6966       code = TREE_CODE (TREE_TYPE (exp));
6967       orig_type = TREE_TYPE (exp);
6968
6969       if (!INTEGRAL_TYPE_P (orig_type)
6970           && code != ERROR_MARK)
6971         {
6972           error ("switch quantity not an integer");
6973           exp = integer_zero_node;
6974           orig_type = error_mark_node;
6975         }
6976       else
6977         {
6978           type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
6979
6980           if (!in_system_header
6981               && (type == long_integer_type_node
6982                   || type == long_unsigned_type_node))
6983             warning (OPT_Wtraditional, "%<long%> switch expression not "
6984                      "converted to %<int%> in ISO C");
6985
6986           exp = default_conversion (exp);
6987           type = TREE_TYPE (exp);
6988         }
6989     }
6990
6991   /* Add this new SWITCH_EXPR to the stack.  */
6992   cs = XNEW (struct c_switch);
6993   cs->switch_expr = build3 (SWITCH_EXPR, orig_type, exp, NULL_TREE, NULL_TREE);
6994   cs->orig_type = orig_type;
6995   cs->cases = splay_tree_new (case_compare, NULL, NULL);
6996   cs->blocked_stmt_expr = 0;
6997   cs->blocked_vm = 0;
6998   cs->next = c_switch_stack;
6999   c_switch_stack = cs;
7000
7001   return add_stmt (cs->switch_expr);
7002 }
7003
7004 /* Process a case label.  */
7005
7006 tree
7007 do_case (tree low_value, tree high_value)
7008 {
7009   tree label = NULL_TREE;
7010
7011   if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
7012       && !c_switch_stack->blocked_vm)
7013     {
7014       label = c_add_case_label (c_switch_stack->cases,
7015                                 SWITCH_COND (c_switch_stack->switch_expr),
7016                                 c_switch_stack->orig_type,
7017                                 low_value, high_value);
7018       if (label == error_mark_node)
7019         label = NULL_TREE;
7020     }
7021   else if (c_switch_stack && c_switch_stack->blocked_stmt_expr)
7022     {
7023       if (low_value)
7024         error ("case label in statement expression not containing "
7025                "enclosing switch statement");
7026       else
7027         error ("%<default%> label in statement expression not containing "
7028                "enclosing switch statement");
7029     }
7030   else if (c_switch_stack && c_switch_stack->blocked_vm)
7031     {
7032       if (low_value)
7033         error ("case label in scope of identifier with variably modified "
7034                "type not containing enclosing switch statement");
7035       else
7036         error ("%<default%> label in scope of identifier with variably "
7037                "modified type not containing enclosing switch statement");
7038     }
7039   else if (low_value)
7040     error ("case label not within a switch statement");
7041   else
7042     error ("%<default%> label not within a switch statement");
7043
7044   return label;
7045 }
7046
7047 /* Finish the switch statement.  */
7048
7049 void
7050 c_finish_case (tree body)
7051 {
7052   struct c_switch *cs = c_switch_stack;
7053   location_t switch_location;
7054
7055   SWITCH_BODY (cs->switch_expr) = body;
7056
7057   /* We must not be within a statement expression nested in the switch
7058      at this point; we might, however, be within the scope of an
7059      identifier with variably modified type nested in the switch.  */
7060   gcc_assert (!cs->blocked_stmt_expr);
7061
7062   /* Emit warnings as needed.  */
7063   if (EXPR_HAS_LOCATION (cs->switch_expr))
7064     switch_location = EXPR_LOCATION (cs->switch_expr);
7065   else
7066     switch_location = input_location;
7067   c_do_switch_warnings (cs->cases, switch_location,
7068                         TREE_TYPE (cs->switch_expr),
7069                         SWITCH_COND (cs->switch_expr));
7070
7071   /* Pop the stack.  */
7072   c_switch_stack = cs->next;
7073   splay_tree_delete (cs->cases);
7074   XDELETE (cs);
7075 }
7076 \f
7077 /* Emit an if statement.  IF_LOCUS is the location of the 'if'.  COND,
7078    THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7079    may be null.  NESTED_IF is true if THEN_BLOCK contains another IF
7080    statement, and was not surrounded with parenthesis.  */
7081
7082 void
7083 c_finish_if_stmt (location_t if_locus, tree cond, tree then_block,
7084                   tree else_block, bool nested_if)
7085 {
7086   tree stmt;
7087
7088   /* Diagnose an ambiguous else if if-then-else is nested inside if-then.  */
7089   if (warn_parentheses && nested_if && else_block == NULL)
7090     {
7091       tree inner_if = then_block;
7092
7093       /* We know from the grammar productions that there is an IF nested
7094          within THEN_BLOCK.  Due to labels and c99 conditional declarations,
7095          it might not be exactly THEN_BLOCK, but should be the last
7096          non-container statement within.  */
7097       while (1)
7098         switch (TREE_CODE (inner_if))
7099           {
7100           case COND_EXPR:
7101             goto found;
7102           case BIND_EXPR:
7103             inner_if = BIND_EXPR_BODY (inner_if);
7104             break;
7105           case STATEMENT_LIST:
7106             inner_if = expr_last (then_block);
7107             break;
7108           case TRY_FINALLY_EXPR:
7109           case TRY_CATCH_EXPR:
7110             inner_if = TREE_OPERAND (inner_if, 0);
7111             break;
7112           default:
7113             gcc_unreachable ();
7114           }
7115     found:
7116
7117       if (COND_EXPR_ELSE (inner_if))
7118          warning (OPT_Wparentheses,
7119                   "%Hsuggest explicit braces to avoid ambiguous %<else%>",
7120                   &if_locus);
7121     }
7122
7123   /* Diagnose ";" via the special empty statement node that we create.  */
7124   if (extra_warnings)
7125     {
7126       tree *inner_then = &then_block, *inner_else = &else_block;
7127
7128       if (TREE_CODE (*inner_then) == STATEMENT_LIST
7129           && STATEMENT_LIST_TAIL (*inner_then))
7130         inner_then = &STATEMENT_LIST_TAIL (*inner_then)->stmt;
7131       if (*inner_else && TREE_CODE (*inner_else) == STATEMENT_LIST
7132           && STATEMENT_LIST_TAIL (*inner_else))
7133         inner_else = &STATEMENT_LIST_TAIL (*inner_else)->stmt;
7134
7135       if (TREE_CODE (*inner_then) == NOP_EXPR && !TREE_TYPE (*inner_then))
7136         {
7137           if (!*inner_else)
7138             warning (0, "%Hempty body in an if-statement",
7139                      EXPR_LOCUS (*inner_then));
7140
7141           *inner_then = alloc_stmt_list ();
7142         }
7143       if (*inner_else
7144           && TREE_CODE (*inner_else) == NOP_EXPR
7145           && !TREE_TYPE (*inner_else))
7146         {
7147           warning (0, "%Hempty body in an else-statement",
7148                    EXPR_LOCUS (*inner_else));
7149
7150           *inner_else = alloc_stmt_list ();
7151         }
7152     }
7153
7154   stmt = build3 (COND_EXPR, void_type_node, cond, then_block, else_block);
7155   SET_EXPR_LOCATION (stmt, if_locus);
7156   add_stmt (stmt);
7157 }
7158
7159 /* Emit a general-purpose loop construct.  START_LOCUS is the location of
7160    the beginning of the loop.  COND is the loop condition.  COND_IS_FIRST
7161    is false for DO loops.  INCR is the FOR increment expression.  BODY is
7162    the statement controlled by the loop.  BLAB is the break label.  CLAB is
7163    the continue label.  Everything is allowed to be NULL.  */
7164
7165 void
7166 c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
7167                tree blab, tree clab, bool cond_is_first)
7168 {
7169   tree entry = NULL, exit = NULL, t;
7170
7171   /* If the condition is zero don't generate a loop construct.  */
7172   if (cond && integer_zerop (cond))
7173     {
7174       if (cond_is_first)
7175         {
7176           t = build_and_jump (&blab);
7177           SET_EXPR_LOCATION (t, start_locus);
7178           add_stmt (t);
7179         }
7180     }
7181   else
7182     {
7183       tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7184
7185       /* If we have an exit condition, then we build an IF with gotos either
7186          out of the loop, or to the top of it.  If there's no exit condition,
7187          then we just build a jump back to the top.  */
7188       exit = build_and_jump (&LABEL_EXPR_LABEL (top));
7189
7190       if (cond && !integer_nonzerop (cond))
7191         {
7192           /* Canonicalize the loop condition to the end.  This means
7193              generating a branch to the loop condition.  Reuse the
7194              continue label, if possible.  */
7195           if (cond_is_first)
7196             {
7197               if (incr || !clab)
7198                 {
7199                   entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
7200                   t = build_and_jump (&LABEL_EXPR_LABEL (entry));
7201                 }
7202               else
7203                 t = build1 (GOTO_EXPR, void_type_node, clab);
7204               SET_EXPR_LOCATION (t, start_locus);
7205               add_stmt (t);
7206             }
7207
7208           t = build_and_jump (&blab);
7209           exit = fold_build3 (COND_EXPR, void_type_node, cond, exit, t);
7210           if (cond_is_first)
7211             SET_EXPR_LOCATION (exit, start_locus);
7212           else
7213             SET_EXPR_LOCATION (exit, input_location);
7214         }
7215
7216       add_stmt (top);
7217     }
7218
7219   if (body)
7220     add_stmt (body);
7221   if (clab)
7222     add_stmt (build1 (LABEL_EXPR, void_type_node, clab));
7223   if (incr)
7224     add_stmt (incr);
7225   if (entry)
7226     add_stmt (entry);
7227   if (exit)
7228     add_stmt (exit);
7229   if (blab)
7230     add_stmt (build1 (LABEL_EXPR, void_type_node, blab));
7231 }
7232
7233 tree
7234 c_finish_bc_stmt (tree *label_p, bool is_break)
7235 {
7236   bool skip;
7237   tree label = *label_p;
7238
7239   /* In switch statements break is sometimes stylistically used after
7240      a return statement.  This can lead to spurious warnings about
7241      control reaching the end of a non-void function when it is
7242      inlined.  Note that we are calling block_may_fallthru with
7243      language specific tree nodes; this works because
7244      block_may_fallthru returns true when given something it does not
7245      understand.  */
7246   skip = !block_may_fallthru (cur_stmt_list);
7247
7248   if (!label)
7249     {
7250       if (!skip)
7251         *label_p = label = create_artificial_label ();
7252     }
7253   else if (TREE_CODE (label) != LABEL_DECL)
7254     {
7255       if (is_break)
7256         error ("break statement not within loop or switch");
7257       else
7258         error ("continue statement not within a loop");
7259       return NULL_TREE;
7260     }
7261
7262   if (skip)
7263     return NULL_TREE;
7264
7265   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
7266 }
7267
7268 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr.  */
7269
7270 static void
7271 emit_side_effect_warnings (tree expr)
7272 {
7273   if (expr == error_mark_node)
7274     ;
7275   else if (!TREE_SIDE_EFFECTS (expr))
7276     {
7277       if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
7278         warning (0, "%Hstatement with no effect",
7279                  EXPR_HAS_LOCATION (expr) ? EXPR_LOCUS (expr) : &input_location);
7280     }
7281   else if (warn_unused_value)
7282     warn_if_unused_value (expr, input_location);
7283 }
7284
7285 /* Process an expression as if it were a complete statement.  Emit
7286    diagnostics, but do not call ADD_STMT.  */
7287
7288 tree
7289 c_process_expr_stmt (tree expr)
7290 {
7291   if (!expr)
7292     return NULL_TREE;
7293
7294   if (warn_sequence_point)
7295     verify_sequence_points (expr);
7296
7297   if (TREE_TYPE (expr) != error_mark_node
7298       && !COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (expr))
7299       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
7300     error ("expression statement has incomplete type");
7301
7302   /* If we're not processing a statement expression, warn about unused values.
7303      Warnings for statement expressions will be emitted later, once we figure
7304      out which is the result.  */
7305   if (!STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7306       && (extra_warnings || warn_unused_value))
7307     emit_side_effect_warnings (expr);
7308
7309   /* If the expression is not of a type to which we cannot assign a line
7310      number, wrap the thing in a no-op NOP_EXPR.  */
7311   if (DECL_P (expr) || CONSTANT_CLASS_P (expr))
7312     expr = build1 (NOP_EXPR, TREE_TYPE (expr), expr);
7313
7314   if (EXPR_P (expr))
7315     SET_EXPR_LOCATION (expr, input_location);
7316
7317   return expr;
7318 }
7319
7320 /* Emit an expression as a statement.  */
7321
7322 tree
7323 c_finish_expr_stmt (tree expr)
7324 {
7325   if (expr)
7326     return add_stmt (c_process_expr_stmt (expr));
7327   else
7328     return NULL;
7329 }
7330
7331 /* Do the opposite and emit a statement as an expression.  To begin,
7332    create a new binding level and return it.  */
7333
7334 tree
7335 c_begin_stmt_expr (void)
7336 {
7337   tree ret;
7338   struct c_label_context_se *nstack;
7339   struct c_label_list *glist;
7340
7341   /* We must force a BLOCK for this level so that, if it is not expanded
7342      later, there is a way to turn off the entire subtree of blocks that
7343      are contained in it.  */
7344   keep_next_level ();
7345   ret = c_begin_compound_stmt (true);
7346   if (c_switch_stack)
7347     {
7348       c_switch_stack->blocked_stmt_expr++;
7349       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7350     }
7351   for (glist = label_context_stack_se->labels_used;
7352        glist != NULL;
7353        glist = glist->next)
7354     {
7355       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
7356     }
7357   nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
7358   nstack->labels_def = NULL;
7359   nstack->labels_used = NULL;
7360   nstack->next = label_context_stack_se;
7361   label_context_stack_se = nstack;
7362
7363   /* Mark the current statement list as belonging to a statement list.  */
7364   STATEMENT_LIST_STMT_EXPR (ret) = 1;
7365
7366   return ret;
7367 }
7368
7369 tree
7370 c_finish_stmt_expr (tree body)
7371 {
7372   tree last, type, tmp, val;
7373   tree *last_p;
7374   struct c_label_list *dlist, *glist, *glist_prev = NULL;
7375
7376   body = c_end_compound_stmt (body, true);
7377   if (c_switch_stack)
7378     {
7379       gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
7380       c_switch_stack->blocked_stmt_expr--;
7381     }
7382   /* It is no longer possible to jump to labels defined within this
7383      statement expression.  */
7384   for (dlist = label_context_stack_se->labels_def;
7385        dlist != NULL;
7386        dlist = dlist->next)
7387     {
7388       C_DECL_UNJUMPABLE_STMT_EXPR (dlist->label) = 1;
7389     }
7390   /* It is again possible to define labels with a goto just outside
7391      this statement expression.  */
7392   for (glist = label_context_stack_se->next->labels_used;
7393        glist != NULL;
7394        glist = glist->next)
7395     {
7396       C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 0;
7397       glist_prev = glist;
7398     }
7399   if (glist_prev != NULL)
7400     glist_prev->next = label_context_stack_se->labels_used;
7401   else
7402     label_context_stack_se->next->labels_used
7403       = label_context_stack_se->labels_used;
7404   label_context_stack_se = label_context_stack_se->next;
7405
7406   /* Locate the last statement in BODY.  See c_end_compound_stmt
7407      about always returning a BIND_EXPR.  */
7408   last_p = &BIND_EXPR_BODY (body);
7409   last = BIND_EXPR_BODY (body);
7410
7411  continue_searching:
7412   if (TREE_CODE (last) == STATEMENT_LIST)
7413     {
7414       tree_stmt_iterator i;
7415
7416       /* This can happen with degenerate cases like ({ }).  No value.  */
7417       if (!TREE_SIDE_EFFECTS (last))
7418         return body;
7419
7420       /* If we're supposed to generate side effects warnings, process
7421          all of the statements except the last.  */
7422       if (extra_warnings || warn_unused_value)
7423         {
7424           for (i = tsi_start (last); !tsi_one_before_end_p (i); tsi_next (&i))
7425             emit_side_effect_warnings (tsi_stmt (i));
7426         }
7427       else
7428         i = tsi_last (last);
7429       last_p = tsi_stmt_ptr (i);
7430       last = *last_p;
7431     }
7432
7433   /* If the end of the list is exception related, then the list was split
7434      by a call to push_cleanup.  Continue searching.  */
7435   if (TREE_CODE (last) == TRY_FINALLY_EXPR
7436       || TREE_CODE (last) == TRY_CATCH_EXPR)
7437     {
7438       last_p = &TREE_OPERAND (last, 0);
7439       last = *last_p;
7440       goto continue_searching;
7441     }
7442
7443   /* In the case that the BIND_EXPR is not necessary, return the
7444      expression out from inside it.  */
7445   if (last == error_mark_node
7446       || (last == BIND_EXPR_BODY (body)
7447           && BIND_EXPR_VARS (body) == NULL))
7448     {
7449       /* Do not warn if the return value of a statement expression is
7450          unused.  */
7451       if (EXPR_P (last))
7452         TREE_NO_WARNING (last) = 1;
7453       return last;
7454     }
7455
7456   /* Extract the type of said expression.  */
7457   type = TREE_TYPE (last);
7458
7459   /* If we're not returning a value at all, then the BIND_EXPR that
7460      we already have is a fine expression to return.  */
7461   if (!type || VOID_TYPE_P (type))
7462     return body;
7463
7464   /* Now that we've located the expression containing the value, it seems
7465      silly to make voidify_wrapper_expr repeat the process.  Create a
7466      temporary of the appropriate type and stick it in a TARGET_EXPR.  */
7467   tmp = create_tmp_var_raw (type, NULL);
7468
7469   /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt.  This avoids
7470      tree_expr_nonnegative_p giving up immediately.  */
7471   val = last;
7472   if (TREE_CODE (val) == NOP_EXPR
7473       && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)))
7474     val = TREE_OPERAND (val, 0);
7475
7476   *last_p = build2 (MODIFY_EXPR, void_type_node, tmp, val);
7477   SET_EXPR_LOCUS (*last_p, EXPR_LOCUS (last));
7478
7479   return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
7480 }
7481
7482 /* Begin the scope of an identifier of variably modified type, scope
7483    number SCOPE.  Jumping from outside this scope to inside it is not
7484    permitted.  */
7485
7486 void
7487 c_begin_vm_scope (unsigned int scope)
7488 {
7489   struct c_label_context_vm *nstack;
7490   struct c_label_list *glist;
7491
7492   gcc_assert (scope > 0);
7493   if (c_switch_stack && !c_switch_stack->blocked_vm)
7494     c_switch_stack->blocked_vm = scope;
7495   for (glist = label_context_stack_vm->labels_used;
7496        glist != NULL;
7497        glist = glist->next)
7498     {
7499       C_DECL_UNDEFINABLE_VM (glist->label) = 1;
7500     }
7501   nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
7502   nstack->labels_def = NULL;
7503   nstack->labels_used = NULL;
7504   nstack->scope = scope;
7505   nstack->next = label_context_stack_vm;
7506   label_context_stack_vm = nstack;
7507 }
7508
7509 /* End a scope which may contain identifiers of variably modified
7510    type, scope number SCOPE.  */
7511
7512 void
7513 c_end_vm_scope (unsigned int scope)
7514 {
7515   if (label_context_stack_vm == NULL)
7516     return;
7517   if (c_switch_stack && c_switch_stack->blocked_vm == scope)
7518     c_switch_stack->blocked_vm = 0;
7519   /* We may have a number of nested scopes of identifiers with
7520      variably modified type, all at this depth.  Pop each in turn.  */
7521   while (label_context_stack_vm->scope == scope)
7522     {
7523       struct c_label_list *dlist, *glist, *glist_prev = NULL;
7524
7525       /* It is no longer possible to jump to labels defined within this
7526          scope.  */
7527       for (dlist = label_context_stack_vm->labels_def;
7528            dlist != NULL;
7529            dlist = dlist->next)
7530         {
7531           C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
7532         }
7533       /* It is again possible to define labels with a goto just outside
7534          this scope.  */
7535       for (glist = label_context_stack_vm->next->labels_used;
7536            glist != NULL;
7537            glist = glist->next)
7538         {
7539           C_DECL_UNDEFINABLE_VM (glist->label) = 0;
7540           glist_prev = glist;
7541         }
7542       if (glist_prev != NULL)
7543         glist_prev->next = label_context_stack_vm->labels_used;
7544       else
7545         label_context_stack_vm->next->labels_used
7546           = label_context_stack_vm->labels_used;
7547       label_context_stack_vm = label_context_stack_vm->next;
7548     }
7549 }
7550 \f
7551 /* Begin and end compound statements.  This is as simple as pushing
7552    and popping new statement lists from the tree.  */
7553
7554 tree
7555 c_begin_compound_stmt (bool do_scope)
7556 {
7557   tree stmt = push_stmt_list ();
7558   if (do_scope)
7559     push_scope ();
7560   return stmt;
7561 }
7562
7563 tree
7564 c_end_compound_stmt (tree stmt, bool do_scope)
7565 {
7566   tree block = NULL;
7567
7568   if (do_scope)
7569     {
7570       if (c_dialect_objc ())
7571         objc_clear_super_receiver ();
7572       block = pop_scope ();
7573     }
7574
7575   stmt = pop_stmt_list (stmt);
7576   stmt = c_build_bind_expr (block, stmt);
7577
7578   /* If this compound statement is nested immediately inside a statement
7579      expression, then force a BIND_EXPR to be created.  Otherwise we'll
7580      do the wrong thing for ({ { 1; } }) or ({ 1; { } }).  In particular,
7581      STATEMENT_LISTs merge, and thus we can lose track of what statement
7582      was really last.  */
7583   if (cur_stmt_list
7584       && STATEMENT_LIST_STMT_EXPR (cur_stmt_list)
7585       && TREE_CODE (stmt) != BIND_EXPR)
7586     {
7587       stmt = build3 (BIND_EXPR, void_type_node, NULL, stmt, NULL);
7588       TREE_SIDE_EFFECTS (stmt) = 1;
7589     }
7590
7591   return stmt;
7592 }
7593
7594 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
7595    when the current scope is exited.  EH_ONLY is true when this is not
7596    meant to apply to normal control flow transfer.  */
7597
7598 void
7599 push_cleanup (tree ARG_UNUSED (decl), tree cleanup, bool eh_only)
7600 {
7601   enum tree_code code;
7602   tree stmt, list;
7603   bool stmt_expr;
7604
7605   code = eh_only ? TRY_CATCH_EXPR : TRY_FINALLY_EXPR;
7606   stmt = build_stmt (code, NULL, cleanup);
7607   add_stmt (stmt);
7608   stmt_expr = STATEMENT_LIST_STMT_EXPR (cur_stmt_list);
7609   list = push_stmt_list ();
7610   TREE_OPERAND (stmt, 0) = list;
7611   STATEMENT_LIST_STMT_EXPR (list) = stmt_expr;
7612 }
7613 \f
7614 /* Build a binary-operation expression without default conversions.
7615    CODE is the kind of expression to build.
7616    This function differs from `build' in several ways:
7617    the data type of the result is computed and recorded in it,
7618    warnings are generated if arg data types are invalid,
7619    special handling for addition and subtraction of pointers is known,
7620    and some optimization is done (operations on narrow ints
7621    are done in the narrower type when that gives the same result).
7622    Constant folding is also done before the result is returned.
7623
7624    Note that the operands will never have enumeral types, or function
7625    or array types, because either they will have the default conversions
7626    performed or they have both just been converted to some other type in which
7627    the arithmetic is to be done.  */
7628
7629 tree
7630 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
7631                  int convert_p)
7632 {
7633   tree type0, type1;
7634   enum tree_code code0, code1;
7635   tree op0, op1;
7636   const char *invalid_op_diag;
7637
7638   /* Expression code to give to the expression when it is built.
7639      Normally this is CODE, which is what the caller asked for,
7640      but in some special cases we change it.  */
7641   enum tree_code resultcode = code;
7642
7643   /* Data type in which the computation is to be performed.
7644      In the simplest cases this is the common type of the arguments.  */
7645   tree result_type = NULL;
7646
7647   /* Nonzero means operands have already been type-converted
7648      in whatever way is necessary.
7649      Zero means they need to be converted to RESULT_TYPE.  */
7650   int converted = 0;
7651
7652   /* Nonzero means create the expression with this type, rather than
7653      RESULT_TYPE.  */
7654   tree build_type = 0;
7655
7656   /* Nonzero means after finally constructing the expression
7657      convert it to this type.  */
7658   tree final_type = 0;
7659
7660   /* Nonzero if this is an operation like MIN or MAX which can
7661      safely be computed in short if both args are promoted shorts.
7662      Also implies COMMON.
7663      -1 indicates a bitwise operation; this makes a difference
7664      in the exact conditions for when it is safe to do the operation
7665      in a narrower mode.  */
7666   int shorten = 0;
7667
7668   /* Nonzero if this is a comparison operation;
7669      if both args are promoted shorts, compare the original shorts.
7670      Also implies COMMON.  */
7671   int short_compare = 0;
7672
7673   /* Nonzero if this is a right-shift operation, which can be computed on the
7674      original short and then promoted if the operand is a promoted short.  */
7675   int short_shift = 0;
7676
7677   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
7678   int common = 0;
7679
7680   /* True means types are compatible as far as ObjC is concerned.  */
7681   bool objc_ok;
7682
7683   if (convert_p)
7684     {
7685       op0 = default_conversion (orig_op0);
7686       op1 = default_conversion (orig_op1);
7687     }
7688   else
7689     {
7690       op0 = orig_op0;
7691       op1 = orig_op1;
7692     }
7693
7694   type0 = TREE_TYPE (op0);
7695   type1 = TREE_TYPE (op1);
7696
7697   /* The expression codes of the data types of the arguments tell us
7698      whether the arguments are integers, floating, pointers, etc.  */
7699   code0 = TREE_CODE (type0);
7700   code1 = TREE_CODE (type1);
7701
7702   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
7703   STRIP_TYPE_NOPS (op0);
7704   STRIP_TYPE_NOPS (op1);
7705
7706   /* If an error was already reported for one of the arguments,
7707      avoid reporting another error.  */
7708
7709   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
7710     return error_mark_node;
7711
7712   if ((invalid_op_diag
7713        = targetm.invalid_binary_op (code, type0, type1)))
7714     {
7715       error (invalid_op_diag);
7716       return error_mark_node;
7717     }
7718
7719   objc_ok = objc_compare_types (type0, type1, -3, NULL_TREE);
7720
7721   switch (code)
7722     {
7723     case PLUS_EXPR:
7724       /* Handle the pointer + int case.  */
7725       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7726         return pointer_int_sum (PLUS_EXPR, op0, op1);
7727       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
7728         return pointer_int_sum (PLUS_EXPR, op1, op0);
7729       else
7730         common = 1;
7731       break;
7732
7733     case MINUS_EXPR:
7734       /* Subtraction of two similar pointers.
7735          We must subtract them as integers, then divide by object size.  */
7736       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
7737           && comp_target_types (type0, type1))
7738         return pointer_diff (op0, op1);
7739       /* Handle pointer minus int.  Just like pointer plus int.  */
7740       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7741         return pointer_int_sum (MINUS_EXPR, op0, op1);
7742       else
7743         common = 1;
7744       break;
7745
7746     case MULT_EXPR:
7747       common = 1;
7748       break;
7749
7750     case TRUNC_DIV_EXPR:
7751     case CEIL_DIV_EXPR:
7752     case FLOOR_DIV_EXPR:
7753     case ROUND_DIV_EXPR:
7754     case EXACT_DIV_EXPR:
7755       /* Floating point division by zero is a legitimate way to obtain
7756          infinities and NaNs.  */
7757       if (skip_evaluation == 0 && integer_zerop (op1))
7758         warning (OPT_Wdiv_by_zero, "division by zero");
7759
7760       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7761            || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7762           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7763               || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
7764         {
7765           enum tree_code tcode0 = code0, tcode1 = code1;
7766
7767           if (code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
7768             tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
7769           if (code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)
7770             tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1)));
7771
7772           if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE))
7773             resultcode = RDIV_EXPR;
7774           else
7775             /* Although it would be tempting to shorten always here, that
7776                loses on some targets, since the modulo instruction is
7777                undefined if the quotient can't be represented in the
7778                computation mode.  We shorten only if unsigned or if
7779                dividing by something we know != -1.  */
7780             shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7781                        || (TREE_CODE (op1) == INTEGER_CST
7782                            && !integer_all_onesp (op1)));
7783           common = 1;
7784         }
7785       break;
7786
7787     case BIT_AND_EXPR:
7788     case BIT_IOR_EXPR:
7789     case BIT_XOR_EXPR:
7790       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7791         shorten = -1;
7792       else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
7793         common = 1;
7794       break;
7795
7796     case TRUNC_MOD_EXPR:
7797     case FLOOR_MOD_EXPR:
7798       if (skip_evaluation == 0 && integer_zerop (op1))
7799         warning (OPT_Wdiv_by_zero, "division by zero");
7800
7801       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7802         {
7803           /* Although it would be tempting to shorten always here, that loses
7804              on some targets, since the modulo instruction is undefined if the
7805              quotient can't be represented in the computation mode.  We shorten
7806              only if unsigned or if dividing by something we know != -1.  */
7807           shorten = (TYPE_UNSIGNED (TREE_TYPE (orig_op0))
7808                      || (TREE_CODE (op1) == INTEGER_CST
7809                          && !integer_all_onesp (op1)));
7810           common = 1;
7811         }
7812       break;
7813
7814     case TRUTH_ANDIF_EXPR:
7815     case TRUTH_ORIF_EXPR:
7816     case TRUTH_AND_EXPR:
7817     case TRUTH_OR_EXPR:
7818     case TRUTH_XOR_EXPR:
7819       if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
7820            || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
7821           && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
7822               || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
7823         {
7824           /* Result of these operations is always an int,
7825              but that does not mean the operands should be
7826              converted to ints!  */
7827           result_type = integer_type_node;
7828           op0 = c_common_truthvalue_conversion (op0);
7829           op1 = c_common_truthvalue_conversion (op1);
7830           converted = 1;
7831         }
7832       break;
7833
7834       /* Shift operations: result has same type as first operand;
7835          always convert second operand to int.
7836          Also set SHORT_SHIFT if shifting rightward.  */
7837
7838     case RSHIFT_EXPR:
7839       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7840         {
7841           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7842             {
7843               if (tree_int_cst_sgn (op1) < 0)
7844                 warning (0, "right shift count is negative");
7845               else
7846                 {
7847                   if (!integer_zerop (op1))
7848                     short_shift = 1;
7849
7850                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7851                     warning (0, "right shift count >= width of type");
7852                 }
7853             }
7854
7855           /* Use the type of the value to be shifted.  */
7856           result_type = type0;
7857           /* Convert the shift-count to an integer, regardless of size
7858              of value being shifted.  */
7859           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7860             op1 = convert (integer_type_node, op1);
7861           /* Avoid converting op1 to result_type later.  */
7862           converted = 1;
7863         }
7864       break;
7865
7866     case LSHIFT_EXPR:
7867       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
7868         {
7869           if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
7870             {
7871               if (tree_int_cst_sgn (op1) < 0)
7872                 warning (0, "left shift count is negative");
7873
7874               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
7875                 warning (0, "left shift count >= width of type");
7876             }
7877
7878           /* Use the type of the value to be shifted.  */
7879           result_type = type0;
7880           /* Convert the shift-count to an integer, regardless of size
7881              of value being shifted.  */
7882           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
7883             op1 = convert (integer_type_node, op1);
7884           /* Avoid converting op1 to result_type later.  */
7885           converted = 1;
7886         }
7887       break;
7888
7889     case EQ_EXPR:
7890     case NE_EXPR:
7891       if (code0 == REAL_TYPE || code1 == REAL_TYPE)
7892         warning (OPT_Wfloat_equal,
7893                  "comparing floating point with == or != is unsafe");
7894       /* Result of comparison is always int,
7895          but don't convert the args to int!  */
7896       build_type = integer_type_node;
7897       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
7898            || code0 == COMPLEX_TYPE)
7899           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
7900               || code1 == COMPLEX_TYPE))
7901         short_compare = 1;
7902       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7903         {
7904           tree tt0 = TREE_TYPE (type0);
7905           tree tt1 = TREE_TYPE (type1);
7906           /* Anything compares with void *.  void * compares with anything.
7907              Otherwise, the targets must be compatible
7908              and both must be object or both incomplete.  */
7909           if (comp_target_types (type0, type1))
7910             result_type = common_pointer_type (type0, type1);
7911           else if (VOID_TYPE_P (tt0))
7912             {
7913               /* op0 != orig_op0 detects the case of something
7914                  whose value is 0 but which isn't a valid null ptr const.  */
7915               if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
7916                   && TREE_CODE (tt1) == FUNCTION_TYPE)
7917                 pedwarn ("ISO C forbids comparison of %<void *%>"
7918                          " with function pointer");
7919             }
7920           else if (VOID_TYPE_P (tt1))
7921             {
7922               if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
7923                   && TREE_CODE (tt0) == FUNCTION_TYPE)
7924                 pedwarn ("ISO C forbids comparison of %<void *%>"
7925                          " with function pointer");
7926             }
7927           else
7928             /* Avoid warning about the volatile ObjC EH puts on decls.  */
7929             if (!objc_ok)
7930               pedwarn ("comparison of distinct pointer types lacks a cast");
7931
7932           if (result_type == NULL_TREE)
7933             result_type = ptr_type_node;
7934         }
7935       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7936                && integer_zerop (op1))
7937         result_type = type0;
7938       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7939                && integer_zerop (op0))
7940         result_type = type1;
7941       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7942         {
7943           result_type = type0;
7944           pedwarn ("comparison between pointer and integer");
7945         }
7946       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7947         {
7948           result_type = type1;
7949           pedwarn ("comparison between pointer and integer");
7950         }
7951       break;
7952
7953     case LE_EXPR:
7954     case GE_EXPR:
7955     case LT_EXPR:
7956     case GT_EXPR:
7957       build_type = integer_type_node;
7958       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
7959           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
7960         short_compare = 1;
7961       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
7962         {
7963           if (comp_target_types (type0, type1))
7964             {
7965               result_type = common_pointer_type (type0, type1);
7966               if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
7967                   != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
7968                 pedwarn ("comparison of complete and incomplete pointers");
7969               else if (pedantic
7970                        && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
7971                 pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
7972             }
7973           else
7974             {
7975               result_type = ptr_type_node;
7976               pedwarn ("comparison of distinct pointer types lacks a cast");
7977             }
7978         }
7979       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
7980                && integer_zerop (op1))
7981         {
7982           result_type = type0;
7983           if (pedantic || extra_warnings)
7984             pedwarn ("ordered comparison of pointer with integer zero");
7985         }
7986       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
7987                && integer_zerop (op0))
7988         {
7989           result_type = type1;
7990           if (pedantic)
7991             pedwarn ("ordered comparison of pointer with integer zero");
7992         }
7993       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
7994         {
7995           result_type = type0;
7996           pedwarn ("comparison between pointer and integer");
7997         }
7998       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
7999         {
8000           result_type = type1;
8001           pedwarn ("comparison between pointer and integer");
8002         }
8003       break;
8004
8005     default:
8006       gcc_unreachable ();
8007     }
8008
8009   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
8010     return error_mark_node;
8011
8012   if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
8013       && (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1))
8014           || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0),
8015                                                     TREE_TYPE (type1))))
8016     {
8017       binary_op_error (code);
8018       return error_mark_node;
8019     }
8020
8021   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
8022        || code0 == VECTOR_TYPE)
8023       &&
8024       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
8025        || code1 == VECTOR_TYPE))
8026     {
8027       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
8028
8029       if (shorten || common || short_compare)
8030         result_type = c_common_type (type0, type1);
8031
8032       /* For certain operations (which identify themselves by shorten != 0)
8033          if both args were extended from the same smaller type,
8034          do the arithmetic in that type and then extend.
8035
8036          shorten !=0 and !=1 indicates a bitwise operation.
8037          For them, this optimization is safe only if
8038          both args are zero-extended or both are sign-extended.
8039          Otherwise, we might change the result.
8040          Eg, (short)-1 | (unsigned short)-1 is (int)-1
8041          but calculated in (unsigned short) it would be (unsigned short)-1.  */
8042
8043       if (shorten && none_complex)
8044         {
8045           int unsigned0, unsigned1;
8046           tree arg0 = get_narrower (op0, &unsigned0);
8047           tree arg1 = get_narrower (op1, &unsigned1);
8048           /* UNS is 1 if the operation to be done is an unsigned one.  */
8049           int uns = TYPE_UNSIGNED (result_type);
8050           tree type;
8051
8052           final_type = result_type;
8053
8054           /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8055              but it *requires* conversion to FINAL_TYPE.  */
8056
8057           if ((TYPE_PRECISION (TREE_TYPE (op0))
8058                == TYPE_PRECISION (TREE_TYPE (arg0)))
8059               && TREE_TYPE (op0) != final_type)
8060             unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0));
8061           if ((TYPE_PRECISION (TREE_TYPE (op1))
8062                == TYPE_PRECISION (TREE_TYPE (arg1)))
8063               && TREE_TYPE (op1) != final_type)
8064             unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1));
8065
8066           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
8067
8068           /* For bitwise operations, signedness of nominal type
8069              does not matter.  Consider only how operands were extended.  */
8070           if (shorten == -1)
8071             uns = unsigned0;
8072
8073           /* Note that in all three cases below we refrain from optimizing
8074              an unsigned operation on sign-extended args.
8075              That would not be valid.  */
8076
8077           /* Both args variable: if both extended in same way
8078              from same width, do it in that width.
8079              Do it unsigned if args were zero-extended.  */
8080           if ((TYPE_PRECISION (TREE_TYPE (arg0))
8081                < TYPE_PRECISION (result_type))
8082               && (TYPE_PRECISION (TREE_TYPE (arg1))
8083                   == TYPE_PRECISION (TREE_TYPE (arg0)))
8084               && unsigned0 == unsigned1
8085               && (unsigned0 || !uns))
8086             result_type
8087               = c_common_signed_or_unsigned_type
8088               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
8089           else if (TREE_CODE (arg0) == INTEGER_CST
8090                    && (unsigned1 || !uns)
8091                    && (TYPE_PRECISION (TREE_TYPE (arg1))
8092                        < TYPE_PRECISION (result_type))
8093                    && (type
8094                        = c_common_signed_or_unsigned_type (unsigned1,
8095                                                            TREE_TYPE (arg1)),
8096                        int_fits_type_p (arg0, type)))
8097             result_type = type;
8098           else if (TREE_CODE (arg1) == INTEGER_CST
8099                    && (unsigned0 || !uns)
8100                    && (TYPE_PRECISION (TREE_TYPE (arg0))
8101                        < TYPE_PRECISION (result_type))
8102                    && (type
8103                        = c_common_signed_or_unsigned_type (unsigned0,
8104                                                            TREE_TYPE (arg0)),
8105                        int_fits_type_p (arg1, type)))
8106             result_type = type;
8107         }
8108
8109       /* Shifts can be shortened if shifting right.  */
8110
8111       if (short_shift)
8112         {
8113           int unsigned_arg;
8114           tree arg0 = get_narrower (op0, &unsigned_arg);
8115
8116           final_type = result_type;
8117
8118           if (arg0 == op0 && final_type == TREE_TYPE (op0))
8119             unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0));
8120
8121           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
8122               /* We can shorten only if the shift count is less than the
8123                  number of bits in the smaller type size.  */
8124               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
8125               /* We cannot drop an unsigned shift after sign-extension.  */
8126               && (!TYPE_UNSIGNED (final_type) || unsigned_arg))
8127             {
8128               /* Do an unsigned shift if the operand was zero-extended.  */
8129               result_type
8130                 = c_common_signed_or_unsigned_type (unsigned_arg,
8131                                                     TREE_TYPE (arg0));
8132               /* Convert value-to-be-shifted to that type.  */
8133               if (TREE_TYPE (op0) != result_type)
8134                 op0 = convert (result_type, op0);
8135               converted = 1;
8136             }
8137         }
8138
8139       /* Comparison operations are shortened too but differently.
8140          They identify themselves by setting short_compare = 1.  */
8141
8142       if (short_compare)
8143         {
8144           /* Don't write &op0, etc., because that would prevent op0
8145              from being kept in a register.
8146              Instead, make copies of the our local variables and
8147              pass the copies by reference, then copy them back afterward.  */
8148           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
8149           enum tree_code xresultcode = resultcode;
8150           tree val
8151             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
8152
8153           if (val != 0)
8154             return val;
8155
8156           op0 = xop0, op1 = xop1;
8157           converted = 1;
8158           resultcode = xresultcode;
8159
8160           if (warn_sign_compare && skip_evaluation == 0)
8161             {
8162               int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
8163               int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
8164               int unsignedp0, unsignedp1;
8165               tree primop0 = get_narrower (op0, &unsignedp0);
8166               tree primop1 = get_narrower (op1, &unsignedp1);
8167
8168               xop0 = orig_op0;
8169               xop1 = orig_op1;
8170               STRIP_TYPE_NOPS (xop0);
8171               STRIP_TYPE_NOPS (xop1);
8172
8173               /* Give warnings for comparisons between signed and unsigned
8174                  quantities that may fail.
8175
8176                  Do the checking based on the original operand trees, so that
8177                  casts will be considered, but default promotions won't be.
8178
8179                  Do not warn if the comparison is being done in a signed type,
8180                  since the signed type will only be chosen if it can represent
8181                  all the values of the unsigned type.  */
8182               if (!TYPE_UNSIGNED (result_type))
8183                 /* OK */;
8184               /* Do not warn if both operands are the same signedness.  */
8185               else if (op0_signed == op1_signed)
8186                 /* OK */;
8187               else
8188                 {
8189                   tree sop, uop;
8190
8191                   if (op0_signed)
8192                     sop = xop0, uop = xop1;
8193                   else
8194                     sop = xop1, uop = xop0;
8195
8196                   /* Do not warn if the signed quantity is an
8197                      unsuffixed integer literal (or some static
8198                      constant expression involving such literals or a
8199                      conditional expression involving such literals)
8200                      and it is non-negative.  */
8201                   if (tree_expr_nonnegative_p (sop))
8202                     /* OK */;
8203                   /* Do not warn if the comparison is an equality operation,
8204                      the unsigned quantity is an integral constant, and it
8205                      would fit in the result if the result were signed.  */
8206                   else if (TREE_CODE (uop) == INTEGER_CST
8207                            && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
8208                            && int_fits_type_p
8209                            (uop, c_common_signed_type (result_type)))
8210                     /* OK */;
8211                   /* Do not warn if the unsigned quantity is an enumeration
8212                      constant and its maximum value would fit in the result
8213                      if the result were signed.  */
8214                   else if (TREE_CODE (uop) == INTEGER_CST
8215                            && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
8216                            && int_fits_type_p
8217                            (TYPE_MAX_VALUE (TREE_TYPE (uop)),
8218                             c_common_signed_type (result_type)))
8219                     /* OK */;
8220                   else
8221                     warning (0, "comparison between signed and unsigned");
8222                 }
8223
8224               /* Warn if two unsigned values are being compared in a size
8225                  larger than their original size, and one (and only one) is the
8226                  result of a `~' operator.  This comparison will always fail.
8227
8228                  Also warn if one operand is a constant, and the constant
8229                  does not have all bits set that are set in the ~ operand
8230                  when it is extended.  */
8231
8232               if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
8233                   != (TREE_CODE (primop1) == BIT_NOT_EXPR))
8234                 {
8235                   if (TREE_CODE (primop0) == BIT_NOT_EXPR)
8236                     primop0 = get_narrower (TREE_OPERAND (primop0, 0),
8237                                             &unsignedp0);
8238                   else
8239                     primop1 = get_narrower (TREE_OPERAND (primop1, 0),
8240                                             &unsignedp1);
8241
8242                   if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
8243                     {
8244                       tree primop;
8245                       HOST_WIDE_INT constant, mask;
8246                       int unsignedp, bits;
8247
8248                       if (host_integerp (primop0, 0))
8249                         {
8250                           primop = primop1;
8251                           unsignedp = unsignedp1;
8252                           constant = tree_low_cst (primop0, 0);
8253                         }
8254                       else
8255                         {
8256                           primop = primop0;
8257                           unsignedp = unsignedp0;
8258                           constant = tree_low_cst (primop1, 0);
8259                         }
8260
8261                       bits = TYPE_PRECISION (TREE_TYPE (primop));
8262                       if (bits < TYPE_PRECISION (result_type)
8263                           && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
8264                         {
8265                           mask = (~(HOST_WIDE_INT) 0) << bits;
8266                           if ((mask & constant) != mask)
8267                             warning (0, "comparison of promoted ~unsigned with constant");
8268                         }
8269                     }
8270                   else if (unsignedp0 && unsignedp1
8271                            && (TYPE_PRECISION (TREE_TYPE (primop0))
8272                                < TYPE_PRECISION (result_type))
8273                            && (TYPE_PRECISION (TREE_TYPE (primop1))
8274                                < TYPE_PRECISION (result_type)))
8275                     warning (0, "comparison of promoted ~unsigned with unsigned");
8276                 }
8277             }
8278         }
8279     }
8280
8281   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8282      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8283      Then the expression will be built.
8284      It will be given type FINAL_TYPE if that is nonzero;
8285      otherwise, it will be given type RESULT_TYPE.  */
8286
8287   if (!result_type)
8288     {
8289       binary_op_error (code);
8290       return error_mark_node;
8291     }
8292
8293   if (!converted)
8294     {
8295       if (TREE_TYPE (op0) != result_type)
8296         op0 = convert (result_type, op0);
8297       if (TREE_TYPE (op1) != result_type)
8298         op1 = convert (result_type, op1);
8299
8300       /* This can happen if one operand has a vector type, and the other
8301          has a different type.  */
8302       if (TREE_CODE (op0) == ERROR_MARK || TREE_CODE (op1) == ERROR_MARK)
8303         return error_mark_node;
8304     }
8305
8306   if (build_type == NULL_TREE)
8307     build_type = result_type;
8308
8309   {
8310     /* Treat expressions in initializers specially as they can't trap.  */
8311     tree result = require_constant_value ? fold_build2_initializer (resultcode,
8312                                                                     build_type,
8313                                                                     op0, op1)
8314                                          : fold_build2 (resultcode, build_type,
8315                                                         op0, op1);
8316
8317     if (final_type != 0)
8318       result = convert (final_type, result);
8319     return result;
8320   }
8321 }
8322
8323
8324 /* Convert EXPR to be a truth-value, validating its type for this
8325    purpose.  */
8326
8327 tree
8328 c_objc_common_truthvalue_conversion (tree expr)
8329 {
8330   switch (TREE_CODE (TREE_TYPE (expr)))
8331     {
8332     case ARRAY_TYPE:
8333       error ("used array that cannot be converted to pointer where scalar is required");
8334       return error_mark_node;
8335
8336     case RECORD_TYPE:
8337       error ("used struct type value where scalar is required");
8338       return error_mark_node;
8339
8340     case UNION_TYPE:
8341       error ("used union type value where scalar is required");
8342       return error_mark_node;
8343
8344     case FUNCTION_TYPE:
8345       gcc_unreachable ();
8346
8347     default:
8348       break;
8349     }
8350
8351   /* ??? Should we also give an error for void and vectors rather than
8352      leaving those to give errors later?  */
8353   return c_common_truthvalue_conversion (expr);
8354 }
8355 \f
8356
8357 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8358    required.  */
8359
8360 tree
8361 c_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED,
8362                 bool *ti ATTRIBUTE_UNUSED, bool *se)
8363 {
8364   if (TREE_CODE (expr) == COMPOUND_LITERAL_EXPR)
8365     {
8366       tree decl = COMPOUND_LITERAL_EXPR_DECL (expr);
8367       /* Executing a compound literal inside a function reinitializes
8368          it.  */
8369       if (!TREE_STATIC (decl))
8370         *se = true;
8371       return decl;
8372     }
8373   else
8374     return expr;
8375 }